INFICON SQM-242 Thin Film Deposition Controller Card Operating Manual User Manual

Page 62

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N 07

SQM-242 Operating Manual

6. Poor thickness
reproducibility.

a. Variable source flux
distribution.

a. Move sensor to a more
central location to reliably
sample evaporant, ensure
constant relative pool height
of melt, avoid tunneling into
the melt.

b. Sweep, dither, or position
where the electron beam
strikes the melt has been
changed since the last
deposition.

b. Maintain consistent source
distribution by maintaining
consistent sweep
frequencies, sweep
amplitude and electron beam
position settings.

c. Material does not adhere
to the crystal.

c. Make certain the crystal
surface is clean; avoid
touching crystal with fingers,
make use of an intermediate
adhesion layer.

d. Cyclic change in rate.

d. Make certain source's
sweep frequency is not
"beating" with the SQM-242
measurement frequency.

7. Large drift in thickness
(greater than 200 Å for a
density of 5.00 g/cc) after
termination of sputtering.

a. Crystal heating due to poor
thermal contact.

a. Clean or polish the crystal
seating surface on the crystal
holder.

b.External magnetic field
interfering with the sensor's
magnetic field (sputtering
sensor.)

b.Rotate sensor magnet to
proper orientation with
external magnetic field, refer
to the sputtering sensor
manual IPN 074-157.

c. Sensor magnet cracked or
demagnetized (sputtering
sensor.)

c. Check sensor magnetic
field strength, the maximum
field at the center of the
aperture should be 700
gauss or greater.

Table 7-2 Troubleshooting Sensors

SYMPTOM

CAUSE

REMEDY