m220_383_02_process_manual工艺手册.pdf.pdf - 第22页
PROCESS SETUP AND ACCEPTANCE P ROCESS M ANU AL 3.3 Alarm handling with Branch and Abort commands 3.3.1 Introduction The Tempress Systems, Inc. process controller, DP C, has som e special features t hat allow alarm condit…
PROCESS SETUP AND ACCEPTANCE
P
ROCESS MANUAL
3.2-2
TS860x 18 2.7 103 5.8 7.4
TS880x 20 2.7 115 6.4 8.2
TS8110x 25 2.7 143 8.0 10.2
TS1280x 20 4 251 14.1 18.0
3.2.3.2 LPCVD process
- due to the low pressure refresh intervals are not an issue. Use the initial gasflows and pressure
settings recommended in the appropriate process description.
- use a flat temperature
Most LPCVD processes exhibit the depletion effect. This shows as a reduction in the deposition rate at the
pump side due to consumption of process gases.
The reason to start of with a flat temperature is to make sure the machine is performing as
expected (and therefore should give a depletion effect). A ramped temperature can be used after that
to counter the expected depletion effects.
3.2.4 Further fine-tuning
Use the trouble shooting tables at each process desciption to fine-tune the process result, meet the
specifications and/or improve the process.
PROCESS SETUP AND ACCEPTANCE
P
ROCESS MANUAL
3.3 Alarm handling with Branch and Abort commands
3.3.1 Introduction
The Tempress Systems, Inc. process controller, DPC, has some special features that allow alarm
conditions to be handled automatically.
A process recipe is made of steps, and within one step several commands can be programmed.
Alarm conditions can be set, and when these conditions are compromised a very specific alarm message is
generated. It is up to the process engineer to decide whether or not action is required on the specific alarm
message.
Three options are available to the process engineer:
1) do nothing, the process recipe continues as programmed
2) branch to another step within the process recipe
3) abort the process recipe, which brings the tube back to step 0 of that process recipe.
The Branch on Alarm command is issued after 3 seconds of consecutive alarm condition and jumps to the
designated step within the same process recipe.
The Abort on Alarm command is issued after 30 seconds of consecutive alarm condition and aborts the
process recipe, either directly into step 0 of that process recipe, or via an assigned Abort Recipe.
3.3.2
Do nothing with an alarms
Some types of alarm conditions are not important enough to stop a running process. These alarms still
need to be fixed, though, and can be traced in long term history using the Tempress Systems, Inc. host
computer system TSC-2 and short term history using the touchscreen alarm status screen.
An example of this type of alarm is a temperature limit alarm during ramping, or a bubbler level alarm
while the bubbler is not used in this particular process recipe.
3.3.3
Handling alarms with the Branch command
Any kind of alarm can be handled by the Branch command. It is often used to finish a process recipe
trying to save valuable process wafers.
Figure 3-1: Branch command jumps to a specified step number
3.3-1
PROCESS SETUP AND ACCEPTANCE
P
ROCESS MANUAL
As the DPC has been designed to remember the last settings until they are changed, it is vital to verify the
settings in the step one branches to.
For example, in step 3 of the schematic above a Branch on Alarm y has been programmed. If this Alarm y
occurs for more than 3 consecutive seconds then the DPC will branch to step 5. While branching it
bypasses any changes programmed in step 4.
3.3.4
Handling alarms with the Abort command
An Abort command can be issued in two ways:
1) programmed in a process recipe in a specific step
2) manually by an operator at any time
If any Abort command is issued the DPC will stop the running process recipe. The DPC will return to
step 0 of the process recipe, either directly or via an Abort Recipe. An Abort recipe also contains steps
and is used to bring the tube in a safe condition.
Note: An Abort recipe must be programmed such that a tube is automatically brought to a SAFE
situation.
As step 0 of the process recipe is the target of an Abort command it should be programmed to contain a
safe condition. In some applications however, such as in a 24hr production environment, this is likely not
the case.
Therefore, the use of an Abort recipe must be applied as soon as in the process recipe potentially
dangerous situations occur when that process recipe is aborted and brought back to step 0.
3.3.4.1 Abort command in a specific step
The programmed Abort command can be used similarly to the Branch on Alarm command. In fact, an
Abort command could be interpreted as a Branch on Alarm to Step 0 command.
Figure 3-2: Abort command initiated from a specific alarm condition without (left) and with (rightt) the use of an
Abort recipe
3.3-2