Utah-94-721002-System-Manual.pdf - 第125页

System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~ =qÉÅÜåçäçÖó== mä~ëã~ä~Ä póëíÉãNMM WARNING BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY . SKQKP= qÜêÉÉJjçåíÜäó= 1) Heater/chiller unit (on closed …

mä~ëã~ä~ÄpóëíÉãNMM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual

WARNING

BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY.

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Examine the exterior of the machine for damage or signs of overheating and for failed

indicator lamps.

Closed loop (recirculating) cooling systems:

Top up with Hexid A40 coolant (Oxford Plasma Technology Part No. G/WTR/SUN/007

for 15 litres). This product is propylene glycol based and is pre-diluted ready for use.

Refer to Appendix S (Services Specifications for Plasmalab and Ionfab systems) sub-

section 2.1 for the warranty impact of not using this product.

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1) Monitor the vacuum integrity of the system by pumping thoroughly, isolating the

process chamber and noting the rate of pressure rise. An abnormally high value (i.e.

> 2mTorr/minute) may indicate a leak or heavy contamination of the process

chamber. (The chamber can be isolated by clicking the Stop button on the

corresponding Pump Control page.)

2) Monitor the backing pump(s)' condition by timing how long it takes to pump from

atmosphere to 0.1 Torr (without a turbomolecular pump turned on). An increase in

time may indicate deteriorating pump performance.

3) Check the zero setting of the Capacitance Manometer (CM gauge). Note that the

CM gauge output does not stabilise until it has been switched on and under vacuum

for 15 minutes. A turbo pumped system will have a base pressure well below

0.1 mTorr, so the zero point can be adjusted readily in this case (see manufacturer's

data). A Roots / rotary combination should give a base pressure below 1 mTorr, and

can be used to set the zero point of a 10 Torr gauge. A rotary pump should give a

base pressure below 10 mTorr, so a true zero pressure cannot be set in this case.

Either the gauge should be set to the same arbitrary reference level (e.g. 10 mTorr),

or it should be set to zero on another vacuum system with a known base pressure,

and carefully re-installed in the System 100.

4) Monitor the performance of each mass flow controller, by noting the system

pressure with 10%, 50% and 100% flow setpoints and the throttle fully open. A

change may indicate a deterioration in MFC performance, or a change in pumping

speed.

Maintenance

UC Davis 94-721001 Issue 1: March 06 Page 6-6 of 22 Printed: 22-Mar-06, 7:41

System Manual lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== mä~ëã~ä~ÄpóëíÉãNMM

WARNING

BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY.

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1) Heater/chiller unit (on closed loop cooling systems).

If the condenser on the refrigeration circuit is air-cooled, it should be kept clean

enough to allow the free flow of air through it. Dirt can be removed by brushing or

vacuum cleaning.

Radio frequency radiation leakage:

Carry out the Radio Frequency radiation leakage tests as detailed in Appendix A

‘Measurement of RF and microwave emissions’.

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1) Replace or clean the filters used in the compressed air supply system.

2) Replace the filters in the cooling water system.

3) Where closed loop (recirculating) water cooling systems are used, drain the system

and replace the coolant with Hexid A40 coolant (Oxford Plasma Technology Part No.

G/WTR/SUN/007 for 15 litres). This product is propylene glycol based and is pre-

diluted ready for use. Refer to Appendix S (Services Specifications for Plasmalab and

Ionfab systems) sub-section 2.1 for the warranty impact of not using this product.

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The operator should be aware that certain process parameters may change as the process gas

bottles pressure drops. For example, inert gas bottles which are normally filled to about 3000

psi, should be changed when the pressure drops below 400 psi. The inlet pressure should be

25 - 35 psia. Before disconnecting the empty bottle it is advisable to thoroughly evacuate the

gas line (by closing the gas bottle tap and pumping the line via the MFC). The line should

then be filled with dry N

if available.

Once the new bottle has been connected, monitor the vacuum integrity of the gas line before

opening the bottle by setting a high flow on the MFC, pumping the line thoroughly (via the

MFC), isolating the process chamber and noting the rate of pressure rise. An abnormally high

value (>2mTorr/minute) may indicate a leak in the gas line or the regulator to bottle

connection.

During normal operation the bottle pressure and line pressure on the cylinder regulator

should be regularly checked for loss of pressure during periods when the gas bottle tap is

turned off (during shut-down periods, overnight or over a weekend). This will indicate a leak

from the gas line or the regulator.

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Where the system is used for Plasma Enhanced Chemical Vapour Deposition (PECVD), the

manual processing runs should be interspersed with etching processes as an efficient method

of cleaning the electrodes and chamber walls.

The etching processes may be optimised to suit particular processing requirements; however,

the following recommendations may be used as a starting point.

Maintenance

Printed: 22-Mar-06, 7:41 Page 6-7 of 22 UC Davis 94-721001 Issue 1: March 06

mä~ëã~ä~ÄpóëíÉãNMM lñÑçêÇ=fåëíêìãÉåíë=mä~ëã~=qÉÅÜåçäçÖó== System Manual

WARNING

BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY.

The etch cleaning should be performed each time the aggregate of the deposition layers

reaches ~10 microns.

The recommended clean process is:

8% or 20%, 700mTorr, 200W, ≥30 minutes

This process is optimised for rapid electrode cleaning. If it is found that the cleaning rate of

the chamber walls is too slow with the above process, then a low pressure process can also be

used:

8% or 20%, 350mTorr, 200W, ≥ 30minutes

The two processes can be alternated until the chamber and electrodes are etched clean.

A chamber conditioning step (using the normal deposition conditions in the empty chamber

to deposit 0.2-0.5µm) is recommended before processing wafers.

Maintenance

UC Davis 94-721001 Issue 1: March 06 Page 6-8 of 22 Printed: 22-Mar-06, 7:41