Ulvac EGO-40M Instruction Manual page 47

MULTI-HEARTH ELECTRON BEAM SOURCE ～EGO-４０M～
Trouble symptom
10. Water leak The vacuum gauge
needle deflects in the pressure
-4
range of 10 when the hearth is
rotated.
11. Frequent abnormal discharge.
Frequency of abnormal discharge
increases when power is applied
above a certain level.
12. The high voltage meter
indication does not increase
when high voltage is turned ON.
13. Evaporant splashes.
14. The evaporation rate decreases.
No change in the input power
and beam spot size. The vacuum
level is normal.
Possible cause
A. Defective seal for the hearth shaft.
B. Defective cooling pipe seal
C. The hearth is perforated.
A. The gun shield is not provided.
B. Abnormal discharge due to gas emitted
from evaporant.
C. Insulation film is formed on the filament
cable and causes charge up.
A. See Item 2.
B. Glow discharge due to high pressure in
the vacuum chamber.
C. Failure of EB power supply.
A. Excessive input power
B. Evaporant is powder.
C. Excessively high beam power density.
D. Poor contact of the filament cable or
filament lead.
E. The hearth is contaminated. Or
evaporant is not sufficiently degassed.
A. Incorrect dimensions of the emitter
assembly.
B. Deformation of the filament (filament life
expiring )
Corrective action
a. Replace the O-ring.
b. Check the surface of the shaft seal for scar. If it is severely scarred,
replace the part.
a. Replace the O-ring.
b. Check the surface of the shaft seal for scar. If it is severely scarred,
replace the parts.
a. Replace the hearth.
a. Provide a gun shield referring to Figure 3.2.
a. Use a high purity evaporant that emits less gas.
b. Decrease power and carry out degassing sufficiently.
a. Remove the filament cable and scrape off the film from the cable or
replace the cable. Check the high voltage feedthrough terminal to see if it
is contaminated with evaporant.
a. See item 2.
a. Check the vacuum level, which must be 10
a. See the power supply instruction manual.
a. Decrease the power to a level at which evaporation can be performed
smoothly.
a. Use a hot-pressed evaporant.
a. Decrease the power.
a. Check terminals to see if they are tight. If loose, retighten them.
a. Clean the hearth.
b. Degass evaporant sufficiently.
c. Change evaporant with a high purity evaporant.
a. Check the dimensions against Figure 5.1.
a. Change the filament.
40
7．TROUBLESHOOTING
-3
Pa or lower.