Page 1 Cryotronics, Inc. No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics, Inc. in these developments. Methods and apparatus disclosed herein may be subject to U.S. Patents existing or applied for.
Page 2 Specifically, except as provided herein, Lake mandatory statutory rights applicable to the sale of the product Shore undertakes no responsibility that the products will be fit for any to you. particular purpose for which you may be buying the Products. Model CRX-6.5K Probe Station...
Page 3 Teflon® and Kapton® are trademarks of DuPont De Nemours. Copyright 2017 Lake Shore Cryotronics, Inc. All rights reserved. No portion of this manual may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the express written permission of Lake Shore.
Page 4 Model CRX-6.5K Probe Station...
Page 5: Table Of Contents
Table of Contents Chapter 1 1.1 General ................1 1.2 Product Description .
Page 6 3.3.9 Unpacking the Options ............55 Model CRX-6.5K Probe Station...
Page 7 3.4 Utility Connections ..............56 3.4.1 Power Connections .
Page 8 5.2.2.3 HT Sample Stage Removal ......... 109 5.2.2.4 Reconfiguring the Model CRX-6.5K for Standard Operation ..109 5.2.2.5 Temperature Operation with the HT Sample Stage .
Page 9 Chapter 6 6.1 General ................127 6.2 Maintenance .
Page 10 6.5.5 Restocking Fee ............. . 151 Model CRX-6.5K Probe Station...
Page 11: General
This chapter serves as a brief introduction to the components that make up a com- plete testing environment with the Model CRX-6.5K station at the core of that sys- tem. Also covered is a brief description of the testing environment and the types of applications for the probe station.
Page 12: Specifications
<20 K with sample at base temperature Probe mount Thermally anchored to sample stage Probe arm Thermally anchored to radiation shield DC/RF probes Electrical isolation >100 for low leakage measurements TABLE 1-1 Model CRX-6.5K probe station specifications Model CRX-6.5K Probe Station...
Page 13 Available for electro-optical measurements Probe landing All probes can land at single point in 25.4 mm (1 in) diameter circle CRYOGEN CONSUMPTION Room to base temperature (total) Not required Helium at 5 K Not required TABLE 1-1 Model CRX-6.5K probe station specifications www.lakeshore.com...
Page 14: Station Details
3.0 kW, 15.5 A full load at 208 V, 60 Hz; 2.6 kW, 13 A full load at 200 V, 50 Hz Cooling water power dissipation (CCR) 3.2 kW 50/60 Hz APPROVAL All instruments CE marked TABLE 1-2 Model CRX-6.5K probe station details Model CRX-6.5K Probe Station...
Page 15: Safety Considerations
Lake Shore Cryotronics, Inc. assumes no liability for customer failure to comply with these requirements. The Model CRX-6.5K probe station protects the operator and surrounding area from electric shock or burn, mechanical hazards, excessive temperature, and spread of fire from the probe station when used as directed in the manual.
Page 16 Earth (ground) terminal yellow; symbol and outline: black Protective conductor terminal CAUTION or WARNING: See instrument documentation; background color: yellow; Frame or chassis terminal symbol and outline: black On (supply) Off (supply) 1-1 Safety symbols FIGURE Model CRX-6.5K Probe Station...
Page 17: General
2.2 Major This section is intended as a reference for identifying assemblies, operator interfaces and controls called out in later chapters. A Model CRX-6.5K probe station comprises Components the probe station itself and five major sub-systems. FIGURE 2-1 illustrates an overall view of the full system.
Page 18: Probe Station
Probe arm Probe arm assembly assembly Baseplate Sample cooling assembly Vacuum chamber CCR second stage Cryocooler vacuum shroud CCR first stage cold head CCR stand Ballast weights Vibration dampening feet FIGURE 2-2 Probe station Model CRX-6.5K Probe Station...
Page 19: Vacuum Chamber And Ccr Vacuum Shroud
2.2.1.1 Vacuum Chamber and CCR Vacuum Shroud Vacuum is important for two reasons. It provides thermal insulation for the cryogenic refrigeration used to cool the sample and radiation shield, and it also prevents particulates and air in the chamber from condensing on the sample, which may lead to sample contamination during measurements.
Page 20: Sample Cooling Assembly
CHAPTER 2: System Overview 2.2.1.2 Sample Cooling Assembly The Model CRX-6.5K sample cooling assembly contains several features to optimize performance and efficiency. Major components of the sample cooling assembly include the two-stage CCR cold head, sample stage, radiation shield stage, radiation shield, and radiation shield viewport.
Page 21: Closed Cycle Refrigerator (Ccr)
2.2.1.3 Closed Cycle Refrigerator (CCR) The cooling engine in the Model CRX-6.5K is a closed cycle refrigerator (CCR) that uses compressed helium gas as the refrigerant. The main components of the CCR are the cold head, compressor unit, flexible helium lines, and the cold head power cable. The cold head is a two-stage, Gifford-McMahon (GM) cycle cryocooler.
Page 22: Micro-Manipulated Stages
CHAPTER 2: System Overview 2.2.1.4 Micro-manipulated Stages Up to six micro-manipulated stages can be installed on the Model CRX-6.5K. The micro-manipulated stage includes x, y and z micro-manipulated translation stages with micrometer or hand dial controls, probe arm base (top feedthrough for user configurable signal connector), bellows, probe arm, arm shield braids, probe arm sensor (provided on one arm), and optional planarization adjustment.
Page 23: Temperature Controller
2.2.2 Temperature The Model CRX-6.5K probe station includes a Model 336 temperature controller. FIGURE 2-8 illustrates the temperature instrumentation and provides a summary of Controller the probe station component that is monitored or controlled by each controller input. FIGURE 2-8 Model 336 temperature controller...
Page 24: Pressurized Gas System
Pure, dry inert gas such as argon or nitrogen is System recommended to purge the vacuum chamber. FIGURE 2-9 illustrates the pressurized gas system. Output pressure gauge Tank pressure gauge Shut-off Gas output Output pressure regulator Pressurized gas tank FIGURE 2-9 Pressurized gas system (profile) Model CRX-6.5K Probe Station...
Page 25: Vision System
2.2.4 Vision System Major components of the vision system include the microscope, color CCD camera, monitor, support and adjustment apparatus, optical fiber cable, and light source. FIGURE 2-10 illustrates the vision system. S-video Monitor cable Color CCD camera Horizontal boom (swing arm) Hand dial Microscope...
Page 26: Configurations, Options And Accessories
Accessories 2.3.1 Probing Each of the six probing positions in the Model CRX-6.5K can be configured with a user specified arm assembly and probe. Arm assemblies are made up of several Configurations components and can be optimized for different probes and measurement techniques.
Page 27: Zn50-Compatible Probe Cables And Connectors
1 GHz. ZN50 series and 40 GHz microwave probes can be interchanged without rewiring the probe arm. Some limitations apply: a ZN50-26U probe mount is required in the Model CRX-6.5K for the ZN50 blades. Semirigid microwave cables are limited to operation below 350 K and are more thermally conductive than ultra-miniature coaxial;...
Page 28: Zn50-Compatible Probe Mount
Microwave probe bodies must be kept below 350 K at all times, but due to the low FIGURE 2-13 Approximate thermal cross section of the probe points, the probe tips can safely probe substrates shape of microwave probe tip that are higher in temperature. FIGURE 2-14 Microwave probe Model CRX-6.5K Probe Station...
Page 29: Microwave-Compatible Cables And Connectors
2.3.3.2 Microwave-Compatible Cables and Connectors A microwave probe cable consists of a microwave semirigid coaxial cable with connectors permanently mounted on each end. There are two frequency configurations for the probe cables, determined by the connector used. The hermetic bulkhead feedthrough has matched connectors to the chosen frequency range. The outer conductor of the semirigid coaxial cable is grounded by the hermetic feedthrough.
Page 30: Optical Fiber Assembly
The sapphire is an excellent electrical insulator and retains good thermal conductivity at cryogenic temperatures. Moderate thermal gradients between the sample stage and sample mounting surface should be expected. The maximum operating temperature is 350 K. Model CRX-6.5K Probe Station...
Page 31: Coaxial Sample Holders
2.3.5.3 Coaxial Sample Holders Coaxial holders offer the ability to define the voltage potential on the conductive sample mounting surface in addition to isolating it from system ground. They are useful when it is desired to maintain the back side of a substrate at a potential other than chassis ground.
Page 32: Lighting Types
It would be difficult to properly land a probe using this image. FIGURE 2-18 Left: Highly reflective surface through a Zoom 70 with a coaxial light; Right: Highly reflective surface through a Zoom 70 with a ring light Model CRX-6.5K Probe Station...
Page 33: Turbo Pumping System (Tps-Frg) And Pumping Kit (Ps-Tp-Kit)
Model CRX-6.5K to operate within specifications. Lake Shore offers turbo pumping Pumping Kit (PS-TP-KIT) systems as the Model TPS FRG option for the Model CRX-6.5K. The components and specifications for the pumping station is listed in TABLE 2-2. The PS-TP-KIT option contains the necessary connections and adapters for connecting the Model TPS FRG to the probe station.
Page 34: High Temperature Option (Ps-Htstage)
(100 W total) that are arranged in parallel; the combined parallel heater resistance is 25 ). The HT stage has a platinum sensor embedded in the top sample plate for oper- ation between 20 K and 675 K in the Model CRX-6.5K. Refer to section 5.2.2 for high temperature stage operation.
Page 35: Considerations For Dc/Rf Electrical Measurements
2.4 Considerations Nearly every DC or RF measurement done in a Model CRX-6.5K has some unique configuration or requirement. Although it is impossible to predict every application, for DC/RF Electrical this section provides information on how to optimize the probe station for some of Measurements the most common measurement challenges.
Page 36: Avoiding Ground Loops
2. Attach cable shields at only one end of the cable if the shield conductor is not being used to establish a return path for the signal. 3. Add resistance in series with reference ground leads in cases where some common mode voltage is present. Model CRX-6.5K Probe Station...
Page 37: Shielding
2.4.1.4 Noise Isolation Every attempt was made in the design and construction of the Model CRX-6.5K to isolate potential noise sources so they do not interfere with measurements. It is important to recognize these features so they are not inadvertently defeated when the probe station is re-configured or set up for measurements.
Page 38: Basic Dc Electrical Measurements
ZN50 Grounded probe sample holder Probe Probe arm shield base CONDUCTOR Sample stage Thermal anchors Radiation shield stage Vacuum chamber base 19-pin Shield To temperature connector controller chassis FIGURE 2-21 Basic configuration for DC measurements Model CRX-6.5K Probe Station...
Page 39: Basic Rf Electrical Measurements
2.4.3 Basic RF Electrical RF measurements can be made with similar configurations described for DC measurements in section 2.4.2. RF measurements are typically configured with Measurements either a BNC signal connector with ultra-miniature cryogenic coaxial cable or a K-connector with a semirigid cable as described in section 2.3.2.2. The usable frequency range of a ZN50 configured with a BNC signal connector with ultra- miniature cryogenic coaxial cable is DC to 50 MHz.
Page 40: Back Side Voltage Biasing
As measured signal magnitude decreases, environmental noise becomes more of an issue. Proper setup of the experiment is crucial to extracting small signals from the Low Noise DC/RF background noise. The Model CRX-6.5K offers several standard features and optional Measurements configurations that can help.
Page 41: Sample Isolation For Low Noise Measurements
Resistance the signal voltage above the noise floor. However, in cryogenic systems like the Model CRX-6.5K, this can lead to unwanted heating of the sample. AC measurement techniques like those used in lock-in-amplifiers are preferred in cryogenic applications because they can separate the signal from noise without excessive current.
Page 42: High Impedance/Low Leakage Measurements
CHAPTER 2: System Overview 2.4.8 High Impedance/ The Model CRX-6.5K can accommodate resistance measurements greater than 100 G), but not without special consideration given to probe station configuration Low Leakage and external electronics. High impedance measurements are difficult for several Measurements reasons.
Page 43: Guarded Probe Station Configurations
The SH-1.25-C or SH-2.00-C coaxial sample holder is recommended for guarding samples in the Model CRX-6.5K. The FT-BNC coaxial feedthrough is used to bring the guard voltage into the chamber and to the sample holder. When the experiment requires guarding and back side voltage biasing or additional ground isolation, the SH-1.25-T or SH-2.00-T triaxial sample holder is required in the...
Page 44: Measurement Voltage Limits
FIGURE 2-28 Guarding with back side voltage bias using a triaxial sample holder 2.4.8.4 Measurement Voltage Limits The Model CRX-6.5K probe station is specified for signal voltages below 60 VDC and 30 V , referred to as non-hazardous live voltage. The sensor, heater and power supply voltages entering the probe station are all below this voltage.
Page 45: Considerations For Microwave Measurements
Model CRX-6.5K. The geometry of the Model CRX-6.5K requires that the cables extend 229 mm (9 in) into the vacuum chamber with a single 90 degree bend. The total length of the microwave cable is approximately 279 mm (11 in).
Page 46: Ground Return Path
Keep in mind that this electrical connection may be broken if desired by removing the anchors from the sample stage; however, please note that this will also remove the thermal connection. Model CRX-6.5K Probe Station...
Page 47: Pad Construction And Impedance Matching
2.5.3 Pad Construction The three points of a GSG microwave probe tip extend the 50 impedance of the semirigid transmission line down to the test substrate. The landing pads on the and Impedance measurement substrate should be 50 impedance coplanar waveguide structured. Matching If the substrate being tested has an impedance of something other than 50 , the...
Page 48: Calibration With The Cs-5 Calibration Standard
VNA measurement reference plane at the end of the probe tips, and thus, removes the losses of the associated cabling and probes from the measurement response of an unknown substrate. FIGURE 2-34 Calibrated S-parameter response of 67 GHz GSG microwave probes Model CRX-6.5K Probe Station...
Page 49: Temperature Effects Of Calibration
2.5.5 Temperature There are temperature dependent losses in microwave feedthroughs, semirigid cables, and probe bodies and tips. As the sample stage cools to 4.2 K, for example, Effects of Calibration there is approximately a 294 K temperature gradient set up over the length of the semirigid coaxial cable.
Page 50: Planarization
Probes also cold weld pad metal to themselves after repeated landings. Nonconductive materials are frequently attached to the pad material, causing contamination. Probe tips should be cleaned regularly to remove contamination. Cleaning instructions are given in section 6.2.7 and section 6.2.8. Model CRX-6.5K Probe Station...
Page 51: Oxidation
2.6.3 Oxidation Oxidation is probably the biggest source of poor contact resistance in a well maintained probe station. Oxidation builds up on the probe and pad metals over time to form an electrically insulating layer that prevents metal to metal contact. The light oxidation that forms between routine uses can normally be wiped clean when the probe is landed.
Page 52 CHAPTER 2: System Overview Model CRX-6.5K Probe Station...
Page 53: General
Much of the equipment described in section 3.2.3 to section 3.2.6 is not included with a standard Model CRX-6.5K probe station or as part of the installation and training service. Some of that equipment can be purchased from Lake Shore as options or accessories;...
Page 54: Space Requirements And Suggested Layout
3.2.1 Space Some consideration should be given to the floor plan before placing the probe station. The Model CRX-6.5K probe station and equipment are relatively compact. The CCR Requirements and compressor comes with flexible helium lines that allow it to be placed as far away as Suggested Layout 3.3 m (10.8 ft).
Page 55: Environmental Requirements And Concerns
The Model CRX-6.5K design incorporates standard features to isolate the sample stage from the vibration of the reciprocating CCR. There are also standard features to help reduce the impact of environmental vibration.
Page 56: Power Requirements
CCR compressor. The Model Requirements CRX-6.5K requires 1-phase power only. Most equipment is designed to operate over a range of line voltages. Some equipment must be configured to operate at a specific voltage within the range listed. This equipment is configured at Lake Shore to the voltage specified when the equipment is ordered.
Page 57: Water Requirements
3.2.4 Water The CCR compressor needs cooling water even for short periods of operation. Cooling water is typically available in several ways: from the municipal (tap) water system, Requirements from a large recirculating cooling system sized for the building or lab, or from a small, dedicated, recirculating chiller sized for the power dissipation of the CCR compressor.
Page 58: Water Routing And Connections
High quality vacuum equipment is necessary for good cooling performance and for keeping the sample clean. You must provide a vacuum pumping system including appropriate gauges and vacuum lines for the Model CRX-6.5K. It must have the ability to attain at least <10 Torr in the probe station while at room temperature.
Page 59: Unpacking The Probe Station
Clear enough space to complete all steps safely. 3.3.1 Shipping The standard components of the Model CRX-6.5K will be shipped in a crate and a palletized box. The crate contains the probe station, and the palletized box contains Containers the CCR.
Page 60: Moving And Lifting The Probe Station
If the Model CRX-6.5K must be moved after the initial installation, use section 3.6.1 and as a guide to reinstall the red spacing washers to lock the inner CCR stand to the outer stand.
Page 61 FIGURE 3-5 Remove the bolts attaching the red, horizontal cross braces to the crate base The Model CRX-6.5K has four lifting eyelets attached to the probe station table for lifting the probe station off the crate base (FIGURE 3-3). To prevent damage to the probe station, do not allow the lifting equipment to contact the bellows or the micromanipulation stages.
Page 62 (FIGURE 3-7). d. Move the long red cross braces out of the work area. Save these in the event that you need to return the probe station. FIGURE 3-7 Removing the cross braces Model CRX-6.5K Probe Station...
Page 63: Unpacking The Probe Station
3.3.7.1 Unpacking the Model 336 Temperature Controller The Model 336 temperature controller provides the temperature monitoring and control for the Model CRX-6.5K. To unpack the controller, remove the packaging and prepare the cables for routing. Refer to the Model 336 user’s manual if you need further information.
Page 64: Unpacking The Probe Starter Kit
Place the compressor in a well ventilated area to avoid asphyxiation in the event of a helium gas leak. Do not enclose the compressor in a confined space that limits the free convection of heat from the unit. Failure to do say may result in malfunction or damage. Model CRX-6.5K Probe Station...
Page 65: Inspecting The Ccr Components
For the standard water-cooled CCR compressor configured with the Model CRX-6.5K probe station, the static pressure reading should be as listed in TABLE 3-6 when the compressor is at room temperature. If any damage is suspected or the gauge reads less than the specified value, contact your Lake Shore representative prior to the scheduled installation.
Page 66: Utility Connections
3.4 Utility Use the following procedures to complete the utility connections required for the Model CRX-6.5K probe station. The items in this section must be completed prior to Connections the arrival of a Lake Shore representative for installation and training. You may also need to refer to the CCR compressor and cold head manual for further information.
Page 67: Pre-Assembly Testing
3.5 Pre-Assembly The following tests are to be performed prior to assembling the probe system configuration to ensure the important subsystems are in proper working condition. Testing 3.5.1 Testing the Turbo A properly functioning turbo vacuum pump and gauge are critical components for probe station operation.
Page 68: Assembling A Basic Probe System Configuration
2. Locate the ¾ in or adjustable wrench provided in the Model CRX-6.5K tool kit. Use it to lower the CCR stand feet until they just touch the red pads. Do not add tension to the feet at this step.
Page 69: Connecting The Ccr Compressor To The Probe Station
(FIGURE 3-11). The CCR stand must be properly positioned and leveled for the Model CRX-6.5K to meet the published vibration specification. FIGURE 3-11 Proper alignment as shown: bellows straight, screws aligned and spacer in place 10.
Page 70: Flexible Helium Line Connection
7. Connect the supply line to the cold head. FIGURE 3-13 Left: On the compressor, connect the return line first, and then connect the supply line; Right: On the cold head, connect the return line first (shown) and then connect the supply line Model CRX-6.5K Probe Station...
Page 71: Cold Head Electrical Cable Connection
3.6.2.2 Cold Head Electrical Cable Connection The cold head electrical cable is shipped in the box with the flexible helium lines. Ensure that the black circuit breaker power switch to the compressor is off before connecting or disconnecting the cold head electrical cable. 1.
Page 72: Connecting The Probe Station
3.6.3 Connecting the There are three cables with varying numbers of inputs and outputs to connect the Model CRX-6.5K probe station. It is helpful to attach the cables in the order presented Probe Station in section 3.6.3.1. The cables are already attached to the back of the instruments, and each one is clearly labeled, but you will need to complete the connections to the probe station.
Page 73: Assembling The Vision System
The vertical post, horizontal boom, microscope and CCD camera are Vision System connected to the Model CRX-6.5K baseplate. The position of the shaft collar determines the height of the microscope above the sample, and may require adjustment after assembly of the vision system.
Page 74: Assembling The Microscope And Horizontal Boom
If the microscope physically touches the vacuum chamber lid, adjust the shaft collar before moving on; section 6.3.4.5 describes how to adjust the shaft collar. FIGURE 3-19 Installing the horizontal boom onto the vertical post Model CRX-6.5K Probe Station...
Page 75: Connecting The Vision System
3.6.4.3 Connecting the Vision System 1. Connect the microscope electronics. These consist of two parts: a. The 12 V DC power supply connects to the plug on top of the microscope. b. S-video cable: connect one end to the top of the microscope as well. It will align in only one direction for the connection (FIGURE 3-20).
Page 76 Connect the power cord to the light source (refer to TABLE 3-1 for power requirements). FIGURE 3-22 Left: Loosen the set screw on the fiber optic cable fitting; Middle: Remove protective fitting; Right: Insert the fiber optic cable Model CRX-6.5K Probe Station...
Page 77: Assembling The Turbo Pumping System
3.6.5 Assembling the Before assembling the turbo vacuum pump with the probe station, it is a good idea to test the turbo vacuum pump alone (section 6.3.1.1). FIGURE 3-23 shows the Turbo Pumping System assembled turbo pumping system. NW 40 0.21 m (8.3 in) 0.5 m (17.6 in)
Page 78 FIGURE 3-25 Install the vacuum line to the pump 4. Remove the blank off plate from the NW 40 vacuum isolation valve on the probe station. The clamp and centering ring are used when the vacuum hose is attached in the next step. Model CRX-6.5K Probe Station...
Page 79: Assembling Probe Station Options
(FIGURE 3-26). FIGURE 3-26 Use the clamp provided to attach the vacuum line to the Model CRX-6.5K probe station To minimize the transfer of vibration to the probe station, position the turbo pumping system so that the vacuum line has at least one 90° bend in it.
Page 80: Installing And Removing Probes
If the probe mount is not installed, please be connector aware that some probe station users find it easier to first install the blade to the probe mount outside the station (section 3.7.2.2), and then install the probe to the probe arm. blade mount Model CRX-6.5K Probe Station...
Page 81: Installing The Zn50 Probe Mount
FIGURE 3-28 CRX-6.5K with probe mount installed 3.7.2.1 Installing the ZN50 Probe Mount 1. Follow the procedure in section 3.7.1. 2. Flex the probe mount braids so that the copper braid block will be in approximately the correct position for attachment (FIGURE 3-29).
Page 82: Installing The Zn50 Probe Blade
Rotate the probe mount and tighten the opposing set screw, keeping the blade all the way back in its slot and flush to the probe mount (FIGURE 3-32). Tighten the screw until the blade does not move with finger pressure. Be Model CRX-6.5K Probe Station...
Page 83: Removing A Zn50 Probe
careful not to over-tighten, as the alumina is delicate and will crack. Rotate the probe back to the upright position. FIGURE 3-32 Left: Slide the blade into its slot; Right: Carefully tighten the probe mount set screws 4. Using the 1.5 mm hex driver, secure the probe to the probe arm by tightening the probe arm set screws.
Page 84 7. Remove the blade from the system and place it back into its storage case, making sure not to contact the delicate probe tip. FIGURE 3-35 Loosening the probe mount set screws Model CRX-6.5K Probe Station...
Page 85: Removing The Zn50 Probe Mount
3.7.3.2 Removing the ZN50 Probe Mount 1. If you have not yet removed the blade, you will need to disconnect the SMA connector. The strain relief to the SMA connector (on the cryogenic coaxial cable) must be held in place with tweezers or your fingers while removing the SMA plug. 2.
Page 86 If the probe body was rotated in order to ease the alignment of the microwave connectors when threading, hold the microwave probe body with your thumb and forefinger as you tighten the set screws to vertically align the probe. Model CRX-6.5K Probe Station...
Page 87: Removing A Microwave Probe
10. Attach the braid block using these steps: a. Use the x, y and z-axis micrometer controls to position the probe so that the braid block can be attached without disturbing the probe tips. b. Using tweezers or your fingers, position the braid block over the mounting holes (FIGURE 3-30).
Page 88: System Verification And Testing
You can find more information on the controller in its manual. 3.8.2 Temperature Each of the four stages in the Model CRX-6.5K (sample stage, radiation shield stage and cryocooler first and second stages) has a temperature sensor and heater. Prior to...
Page 89: Ccr Operation Test
If the CCR is not operational, the temperature will settle to a temperature above the actual setpoint. 6. Turn the sample stage heater off. 7. Set the temperature setpoint to zero. 8. Repeat steps 4 to 7 for the remaining stages, one at a time. If any of the stages do not raise 5 K and stabilize, the most likely reason for the failure is the cabling;...
Page 90: Microscope Light And Focus Test
1. Land each probe tip on the top surface of the grounded sample holder (section 4.6.2). 2. Using a multimeter, measure continuity (resistance) between each adjacent pair of probes. Model CRX-6.5K Probe Station...
Page 91: Vacuum Chamber Leak Test
3. A bad probe assembly can be identified if it does not show continuity (low resistance) with the probes on either side. 4. If a probe assembly appears bad, first re-land the probe to make sure it is touching the sample stage, then refer to section 6.3.5. 3.8.7 Vacuum Chamber Follow this procedure to verify vacuum chamber integrity.
Page 92 CHAPTER 3: Installation and Setup Model CRX-6.5K Probe Station...
Page 93: General
Chapter 4: Basic Operation 4.1 General This chapter describes the majority of daily operation. Chapter 5 covers more advanced probe station operation. It is assumed that the station has been installed and set up as described in Chapter 3. 4.1.1 Common The following are some common mistakes that can be made while operating the probe station.
Page 94: Operating The Probe Arm Translation Stages
25 mm (1 in) diameter probe area in the center of the sample holder Translation Stages (FIGURE 4-1). The Model CRX-6.5K can accommodate 32 mm (1.25) and 51 mm (2 in) sample holders, but the probe area is the same for both sizes. Individual probes can land outside the probe area in line with the probe arm.
Page 95 The z-axis micrometer is used to move the probe up and down (vertically) with a total travel of 17 mm (0.71 in). Turning the micrometer clockwise moves the probe down. One complete revolution of the micrometer moves the probe 0.5 mm. The graduated scale on the outside of the micrometer shows 0.01 mm divisions.
Page 96: Sample Exchange
The screws are captive and stay with the radiation shield lid. 9. Place the radiation shield lid with the vacuum chamber lid. Bumpers are built into the radiation shield lid for it to rest on. Model CRX-6.5K Probe Station...
Page 97: Removing The Sample Holder
4.3.2 Removing The Follow this procedure to remove the sample holder. Sample Holder 1. If you are removing an optional triaxial or coaxial sample holder, disconnect the signal cable before removing the sample holder from the sample stage (FIGURE 4-4). Using tweezers or your fingers, pull the cable plug out of the sam- ple holder socket.
Page 98: Mounting Samples On The Sample Holder
Apiezon N® grease is available from Lake Shore. 2. Clamping: a small amount of pressure applied with clamps can significantly improve thermal contact between the sample and sample holder. Clamping can Model CRX-6.5K Probe Station...
Page 99: Semi-Permanent Mounting
also be used to improve the effectiveness of grease as a thermal contact. Users often make simple clamping fingers to fit their sample and hold them down with M3 screws in the tapped holes intended for the lifter tool. 3. Adhesive tape: tape over the corners or edges of a sample with vacuum compatible tape that has a silicon adhesive.
Page 100: Permanent Mounting
Be very careful that the tweezers do not slip off the cable plug and onto the wire, where they can accidentally pull the wire out of the connector. 9. If you are using microwave probes, make sure translation and planarization are within range (section 4.6.3). Model CRX-6.5K Probe Station...
Page 101: Closing The Vacuum Chamber And Radiation Shield
4.3.5 Closing the Follow this procedure to close the vacuum chamber and radiation shield. Vacuum Chamber and Radiation Shield Lake Shore recommends that you practice imaging the sample and landing the probes (section 4.6) before closing the vacuum chamber and radiation shield for cool down. 1.
Page 102: Vacuum Operation
However, if the pump vents while the sample cooling assembly is cold, water vapor will condense on the it and freeze into damaging ice. It can take approximately a week to return the probe station to proper working order (if this Model CRX-6.5K Probe Station...
Page 103: Vacuum Gauge Location
does happen, please refer to section 6.2.12). It is possible that the sample cooling assembly may suffer irreparable damage. Never operate the probe station above room temperature without the CCR on and the probe station under vacuum. When operating the sample stage above room temperature, it is best to leave the vacuum isolation valve open and the pump running during operation.
Page 104: Evacuating The Vacuum Chamber
4. You will hear hissing as the manual vent valve is opened and air rushes into the turbo pump. Once the hissing ceases, completely close the manual vent valve. Remember you will always need to purge the vacuum chamber and open the vacuum isolation valve before restarting the pump. Model CRX-6.5K Probe Station...
Page 105: Purging The Vacuum Chamber
2. Attach the gas line to the p in NPT purge valve fitting. A p in NPT to p in OD tube adapter is included in the Model CRX-6.5K spares kit. 3. Regulate the gas pressure from 6.89 kPa to 13.79 kPa (1 psi to 2 psi).
Page 106: Temperature Operation
The cooling engine in the CRX-6.5K is a two-stage closed cycle refrigerator (CCR). The sample stage and probes are thermally connected to the CCR 2nd stage through vibration isolation: the radiation shield stage and probe arms are thermally connected to the CCR 1st stage through similar vibration isolation.
Page 107: Electronic Temperature Controls
CRX-6.5K stage temperatures. The Model 336 has four sensor inputs and two independent control outputs. Only the two PID (proportional, integral, derivative) control outputs of the Model 336 are used in the standard Model CRX-6.5K configuration (refer to Chapter 2 of the instrument manuals for details).
Page 108: Allowing The Sample And Radiation Shield Stages To Cool
4.5.3 Operating the Follow this procedure to operate the sample stage from base temperature to 350 K. Base temperature of the Model CRX-6.5K depends on configuration; refer to Sample Stage from section 1.3 for temperature specifications. The sample stage is the only stage actively Base Temperature to controlled to a temperature setpoint during normal operation.
Page 109: Returning To Room Temperature
The temperature controller configuration table (TABLE 4-2) and the CCR and electronic control settings table (TABLE 4-4 and TABLE 4-5) summarize the typical Control Summary settings needed to maintain the Model CRX-6.5K temperature control. TABLE 4-5 provides the sample stage electronic control settings. Temperature...
Page 110 Proportional (P) Integral (I) Derivative (D) Heater power values are based on a 4-arm configuration with probe mounts tied to the sample stage. TABLE 4-5 Base temperature and up electronic control settings for the sample stage Model CRX-6.5K Probe Station...
Page 111: Imaging And Probing The Sample
4.6 Imaging and A clear image of the sample is necessary for properly landing the probe tip. Landing the tip with a poor image can result in intermittent contact, scratches on the sample Probing the or probe damage. If you cannot obtain a proper image, please refer to section 6.3.4. Sample Lake Shore recommends that you practice imaging the sample and landing probes before cooling the probe station.
Page 112: Landing The Probe
9. The desired position of the probes with respect to the edge of the pads and the desired amount of skating should be determined and used as a lab standard to ensure consistent results. Raise all probes 3 mm to 4 mm above the sample before changing temperature or vacuum. Model CRX-6.5K Probe Station...
Page 113: Using The Planarization Assembly
Planarization hardware is included on all Model CRX-6.5K probe assemblies that were initially configured with microwave cables or probes. Probe assemblies can be upgraded in the field if microwave probes are purchased later.
Page 114 Tighten the bottom two screws first, and then tighten the top two screws. 9. Check the planarization once more to be sure tightening the bellows’ screws did not change the angle. 10. See section 2.5 for more information on making microwave measurements. Model CRX-6.5K Probe Station...
Page 115: General
On some vacuum systems, vacuum base pressure can be improved through a “bake out” process to increase the energy in contaminant molecules so they move away from the surfaces and can be pumped out more quickly. The Model CRX-6.5K cannot be baked out, because its components will not tolerate the high temperatures required;...
Page 116: While Cooling The Probe Station
6. Operate the probe station normally. 5.2.2 High Temperature The Model CRX-6.5K probe station can be operated from 20 K to 675 K using the high temperature (HT) sample stage option. The HT sample stage is a coaxially isolated Sample Stage stage that is designed for 51 mm (2 in) diameter wafers.
Page 117 c. Leave the banana style connector loose, ensuring that it is not contacting any other connectors. 3. Connect the HT sample stage temperature control and sensing cable (labeled DC2048) to the rear panel of the Model 336 temperature controller as follows: a.
Page 118: Ht Sample Stage Installation
TABLE 5-2 Model 336 temperature controller output settings for the HT sample stage connected to Output 1 5.2.2.2 HT Sample Stage Installation The HT sample stage installation in the Model CRX-6.5K probe station is similar to the sample holder installation. These instructions assume that you are familiar with section 4.3 in this manual.
Page 119: Ht Sample Stage Removal
Follow the procedures in Chapter 4 to install the radiation and vacuum chamber lids and evacuate the probe station. 5.2.2.3 HT Sample Stage Removal The HT sample stage removal from the Model CRX-6.5K is similar to the sample holder removal. Follow this procedure to remove the HT sample stage from the Model CRX-6.5K.
Page 120: Temperature Operation With The Ht Sample Stage
CCR second stage must not be operated above 350 K. The steps to cool the Model CRX-6.5K probe station with the HT sample stage are the same for normal operation; however, because of the increased thermal isolation between the HT sam- ple stage and the CCR second stage, longer settling times should be expected when controlling to a temperature setpoint.
Page 121: Probe Arm Assembly Reconfiguration
Operating HT sample Probe station cool Maintaining sample Returning probe station stage at temperature down stage at base temp to room temperature above base Main power CCR control settings On/Off HT sample stage Heater range High (100 W) High (100 W) Electronic Nominal power —...
Page 122 Slide the spade lug under the hex screw head and washer (FIGURE 5-8). c. Using a 7 mm wrench, tighten the hex screw (FIGURE 5-8). d. Use the same procedure to attach the other braid to the other side of the awning. Model CRX-6.5K Probe Station...
Page 123: Removing A Micro-Manipulated Translation Stage (Mms-07)
12. Remove anything temporarily fastening the cable to the end of the probe arm. Take care not to remove the tape that electrically insulates the SMA connector (FIGURE 5-15). FIGURE 5-8 Left: Slide the spade lug under the hex screw head and washer; Right: Tighten the hex screw 5.3.2 Removing a This section provides directions for removing a micro-manipulated translation stage.
Page 124: Removing A Probe Arm And Base
3. Compress the bellows to make room to slide it carefully off the probe arm. When you reach the end of the probe arm, you will need to tilt it up to remove it from the probe arm (FIGURE 5-12). Place the bellows on a clean, lint-free cloth or wipe. Model CRX-6.5K Probe Station...
Page 125 FIGURE 5-12 Left: Remove the four horizontal screws that attach the bellows to the z-axis stage; Right: Compress the bellows to remove it from the probe arm 4. If you do not have a planarization assembly, loosen the M4 screw that holds the stabilization bracket to the probe arm base.
Page 126: Installing A Probe Arm And Base
Place the tape near the end of the cable so it can be removed after the assembly is installed (FIGURE 5-15). FIGURE 5-15 Left: Securing the planarization assembly to the probe arm base; Right: Taping the cable to the probe arm Model CRX-6.5K Probe Station...
Page 127: Reconfiguring Ultra-Miniature Cryogenic Coaxial Cables
6. Clean the o-ring groove in the probe arm base (FIGURE 5-14). Clean, inspect and lightly grease the o-ring with vacuum grease and place it in the groove. 7. Place the bellows over the arm; grasp the square end and carefully twist it down until the flange meets the probe arm base (FIGURE 5-16).
Page 128 Remove the ZN50 probe to prevent damage to the probe tip. 8. Install the probe arm and base using the steps in section 5.3.4. 9. Install the micro-manipulated stage using the steps in section 5.3.1. 10. Install a ZN50 probe using section 3.7.2. Model CRX-6.5K Probe Station...
Page 129: Reconfiguring Microwave Cables
5.3.6 Reconfiguring If you will be changing cables frequently, it is recommended to have a probe arm available with the appropriate cable already installed, then switch probe arms using Microwave Cables the instructions in section 5.3.3 and section 5.3.4. However, if a cable change is nec- essary, you can follow this procedure to do so.
Page 130: Adjusting The Fit Of Microwave Cables
FIGURE 5-21 Left: Rotate the feedthrough assembly into position and re-tighten the connection; Right: The off-centered position on the cable feedthrough assembly 6. Start but do not tighten all four feedthrough assembly screws. Model CRX-6.5K Probe Station...
Page 131 7. Gently push or pull both of the probe ends of the semirigid cable in the desired direction required for adjustment. With gentle wiggling of the probe end, the cable should slide through the unwaxed dental floss that is holding it to the ther- mal anchor on the probe arm.
Page 132: Reconfiguring An Optical Fiber Assembly
5. Using a 2.5 mm hex driver, attach the feedthrough extension to the probe arm base with four M3 screws (FIGURE 5-23). 6. Lightly grease the extension o-ring, and place it in the groove. Do not loosen the nut between the cable and the flange (FIGURE 5-23). Model CRX-6.5K Probe Station...
Page 133 FIGURE 5-23 Left: Attaching the feedthrough extension to the probe arm base; Right: The nut between the cable and the flange—SMA style shown 7. If there is any cellophane tape on the optical fiber, remove it. 8. Insert the optical fiber tip into the feedthrough extension (FIGURE 5-24). Handle the fragile optical fiber carefully;...
Page 134 16. Attach the braid block following step 5, a to c in section 3.7.2.1. 17. Before initiating a cryogen transfer, test probe arm reach. It is very costly and time consuming to initiate cool down only to find the probe mount braids pre- vent full probe travel. Model CRX-6.5K Probe Station...
Page 135: Installing The Planarization Assembly
5.3.8 Installing the You will need to install the planarization assembly if the micro-manipulated stage was not configured with one, and you intend to use microwave probes. The planariza- Planarization Assembly tion assembly allows the microwave probe to be rotated so that all three points on the microwave probe tip touch the sample at the same z-axis position.
Page 136 If these screws are over-torqued, the z-axis stage and bel- lows may be damaged. FIGURE 5-29 Left: Thread the nut onto the bottom of the shaft; Right: Tighten the four long horizontal M4 screws Model CRX-6.5K Probe Station...
Page 137: General
Chapter 6: Maintenance and Troubleshooting 6.1 General This chapter covers maintenance, troubleshooting and field service instructions. Instructions for contacting Lake Shore and arranging product service are in section 6.5. 6.2 Maintenance This section includes both a preventive maintenance schedule and maintenance instructions, unless those instructions are included elsewhere in this manual.
Page 138: Cleaning The Vacuum Chamber Exterior
Interior higher base temperatures. If the Model CRX-6.5K chamber is not properly maintained, it will be increasingly difficult to operate the sample stage at the specified base temperature.
Page 139: Viewport Window Maintenance
6.2.4 Viewport Window Viewport windows require extra consideration. It is important to protect the optics as they are your only way to view and photograph the activity on the sample holder. Maintenance 6.2.4.1 Cleaning the Viewport Windows The viewport windows on the radiation shield lid and vacuum chamber lid will need cleaning, as they collect debris and smudges during normal operation.
Page 140: Accessing Other O-Rings
It can be accessed using instructions in section 5.3.6.3 (third method) as a guide. Vacuum chamber ports: the NW 25 gauge port on the Model CRX-6.5K chamber has an o-ring sealing the blank-off flange to the chamber.
Page 141: Cleaning Becu Probe Tips
VGE-7031 varnish can be removed using equal parts ethanol and toluene After removing the mounting material, wipe with a lint-free cloth to remove any solvent residue. Finish with an isopropyl alcohol rinse. 6.2.7 Cleaning BeCu Probe tips made of beryllium copper have a normal shelf-life of about one month before they develop an oxide layer which may impede good electrical contact.
Page 142: Cleaning Microwave Probe Points
4. Install the probe arm and base using the instructions in section 5.3.4. 5. Install the micro-manipulated stage using the instructions in section 5.3.1. Model CRX-6.5K Probe Station...
Page 143: Ccr Maintenance
6.2.11 Vacuum Pump It is difficult to give specific instructions for all possible combinations of pumps that may be used with the Model CRX-6.5K. Refer to the information included with your Maintenance selected vacuum pump for specific maintenance instructions, and add them to the preventive maintenance schedule in section 6.2.1 of this manual.
Page 144: Diaphragm Pumps
Torr, then go on to step 9; if not, contact the Lake Shore service department because the system may have a vacuum leak or other damage. 9. Use the procedures in section 3.8 to ensure basic functionality of the probe sta- tion and vacuum pump. Model CRX-6.5K Probe Station...
Page 145: Troubleshooting Procedures
Lake Shore service or your local representative before beginning these procedures. Contact information is in section 6.5. 6.3.1 Vacuum The Model CRX-6.5K should be able to achieve a vacuum of <10 Torr at room temperature with an appropriate vacuum system and the gauge located on the Troubleshooting chamber.
Page 146: Testing The Turbo Vacuum Pump Alone
7. Do not continue to the next steps if this pressure is not achieved; see section 6.3.1 or contact Lake Shore for technical assistance (see section 6.5). 8. If 10 Torr is achieved, turn off the turbo pump, and vent the turbo. Model CRX-6.5K Probe Station...
Page 147: Testing The Vacuum Pumping System, The Connection To The Probe Station And The Probe Station Vacuum Chamber
6.3.1.3 Testing the Vacuum Pumping System, the Connection to the Probe Station and the Probe Station Vacuum Chamber 1. Leave the vacuum pumping system connected to the probe station as in the pre- vious section. 2. Make sure that the vacuum pumping system is vented to atmosphere (use the manual vent valve on the side of the turbo pump), and the probe station vacuum chamber is vented to atmosphere (use the purge valve and procedure in section 3.6.5.1).
Page 148: Will Not Achieve
CHAPTER 6: Maintenance and Troubleshooting FIGURE 6-4 Vacuum gauge on the Model CRX-6.5K vacuum chamber 1. Install a vacuum gauge to the available NW 25 gauge port on the vacuum cham- ber or on the chamber side of the vacuum isolation valve. The NW 40 T from the PS-V81DPC may be placed between the vacuum isolation valve and the chamber as shown in section FIGURE 6-4.
Page 149: Will Not Achieve Less Than
Remove, clean, inspect for damage, grease, and reinstall the vacuum chamber lid o-ring. Make sure the o-ring is not twisted. Check the torque on fasteners between the bellows and arm base; see section 5.3.4. Do not over-tighten these fasteners or new leaks can be created. As an aid in identifying the source of the leak, place a few drops of isopropyl alcohol on the suspected area and look for an observable change in the vacuum gauge reading.
Page 150: Ccr Troubleshooting
6.3.3.1 Probe Station Does Not Begin to Cool Use this section if the Model CRX-6.5K stages do not begin to cool. The first step is to make sure that all temperature controller heater loops are turned off or have a 0 K setpoint.
Page 151: Takes Too Long To Cool
(FIGURE 6-5), investigate the possible causes listed in section 6.3.3.2 to section 6.3.3.4. FIGURE 6-5 Typical Model CRX-6.5K sample cooling assembly cooling curve with 4 arms 6.3.3.6 Erratic Temperature Readings The Model CRX-6.5K sample stage is a stable temperature control platform and reasonable temperature control can be achieved over the entire temperature range.
Page 152: Image System Troubleshooting
6.2.4. In severe cases, persistent fogging can indicate poor chamber vacuum; see section 6.3.1. When checking for fog, also check for smudges on the microscope lens or on any of the viewports and clean as needed (section 6.2.4). Model CRX-6.5K Probe Station...
Page 153: Height Adjustment
6.3.4.5 Height Adjustment The range of focus of the microscope is quite short, as small as 34 µm on some systems. It is common for a microscope that is set up for thick samples to be incapable of focusing on the sample holder or thin samples. Follow this procedure if the microscope does not focus on the sample surface: 1.
Page 154: Poor Contrast Images
This section addresses images that are poor in contrast, show little or no sample definition and have little response to small changes in light intensity. This problem is difficult to troubleshoot primarily because of the geometry of the Model CRX-6.5K itself. The relatively long distance between microscope and sample and two optic viewports in between offer significant challenges to conventional image systems.
Page 155: Probe Troubleshooting
FIGURE 6-7 Loosening the camera rotating joint to adjust the camera image orientation 6.3.5 Probe The three most common issues that arise with probes fall in three categories: bent or broken probe tips, poor or non-ohmic electrical contact, or a loss of continuity. Troubleshooting 6.3.5.1 Bent or Broken Probe Tips Probe tips by nature are delicate and must be handled with care both inside and...
Page 156: Poor Or Non-Ohmic Electrical Contact
SMA connector. If the resistance is not approximately zero, the cable must be replaced. Refer to section 5.3.5 for the procedure to replace the cable. Model CRX-6.5K Probe Station...
Page 157: Service Reference
6.4.1 Power Electrical power is required for the operation of the Model 336 temperature controller, vision system, turbo pumping system, and CCR compressor. The CRX-6.5K Requirements requires 1-phase power only. Most equipment is designed to operate over a range of line voltages.
Page 158: Pin Outs
Drain wire connected to single banana, which plugs into chassis next to heater output of controller. The other end of the drain wire is connected to the body of the 19-pin mating connector. TABLE 6-4 Pin outs for the control and readout cables of the system Model CRX-6.5K Probe Station...
Page 159: Instrumentation Wiring Diagram
6.4.3 Instrumentation FIGURE 6-8 shows the system wiring diagram. It details the electrical interconnec- tions for the probe station and Model 336 temperature controller. Lake Shore part Wiring Diagram numbers of individual cables are also shown. Contact Lake Shore if you need replace- ment cables.
Page 160 CHAPTER 6: Maintenance and Troubleshooting FIGURE 6-8 Instrumentation wiring diagram Model CRX-6.5K Probe Station...
Page 161: Technical Inquiries
You will receive a response within 24 hours, or the next business day in the event of weekends or holidays. If you wish to contact Systems Service by mail or telephone, use the following: Lake Shore Cryotronics, Inc. 575 McCorkle Blvd. Westerville, Ohio 43082 USA...
Page 162 CHAPTER 6: Maintenance and Troubleshooting Model CRX-6.5K Probe Station...
Page 163 Index settings 98 leakage current 18 light source 16 assembly 55 image quality 145 microscope 61 DC measurements 28 power requirements 44 pump line vibration isolator DC/RF (ZN50) probe configura- tions 17 troubleshooting 143 turbo pumping system 65 DC/RF measurements 25 low resistance samples 31 small signal low noise 30 vision system 61...
Page 164 10 moving and lifting the probe planarization assembly 19 cooling curve 142 station 48 installation 123 cryopump 137 options 53 use 100 electronic controls 98 tools required 48 power requirements 44 image 10 Model CRX-6.5K Probe Station...
Page 165 vacuum chamber 9 cleaning 128 closing the shields 88 evacuating 91 ground reference 26 purging 92 removing condensation 134 shielding 27 vacuum levels 91 vacuum gauge 16 image of 66 installing 65 location 90 vacuum requirements 46 vacuum troubleshooting 135 Vector Network Analyzer 20 vibration 43 vibration isolation 67...
Page 166 INDEX Model CRX-6.5K Probe Station...

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