Ulvac EGL-206M Instruction Manual page 53

Trouble symptom
9. Evaporant adheres to the
hearth. Or the hearth is
gouged on the filament side.
10. Water leak The vacuum
gauge needle deflects in the
-4
pressure 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.
Possible cause
A. Insufficient cooling of the hearth
B. The beam spot is deflected.
A. Defective seal for the hearth shaft.
B. Defective cooling pipe seal for the
coils
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.
SECTION 7
a. Check the water flow rate, which must be 10 /min or more.
b. Check the water temperature, which must be 25 C or lower.
c. Check the water flowing direction in the hearth.
See Fig. 3.3.
d. Check water for purity.
Water resistivity of 5 -cm or more is recommended.
a. Position the beam spot at the center of the crucible so that heat
is dissipated uniformly in the radial direction.
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 feed-through
terminal to see if it is contaminated with eva-porant.
a. See item 2.
a. Check the vacuum level, which must be 5 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.
43
Corrective action
-2
Pa or lower.