m220_383_02_process_manual工艺手册.pdf.pdf - 第21页
PROCESS SETUP AND ACCEPTANCE P ROCESS M ANU AL 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 p rocess - due to the low pressure r efresh in…
PROCESS SETUP AND ACCEPTANCE
P
ROCESS MANUAL
3.2-1
3.2 Process recipe startup and fine-tuning
3.2.1 Introduction
Process fine-tuning is required to reach the guaranteed process specifications and improve a current
process. Many different methods lead to the same process result and any approach is valid as long
as it satisfies the specifications. A few tips are described here that can be used as a guideline for
process fine-tuning.
3.2.2
Prerequisites
The following items are required before process fine-tuning can be started.
- a fully functional system (leaktested, profiled)
- a process recipe
- appropriate temperature recipes
3.2.3
Initial settings
The initial settings can be copied from an existing recipe if that is available. Alternatively, the
example recipes given later in this manual can be used. These recipes are based on a default system,
therefore the example recipes need to be adapted to fit the customer specific machine.
Two different process conditions occur. The atmospheric processes and the LPCVD processes.
3.2.3.1 Atmospheric process
- calculate the required gasflow to obtain a refresh interval of 3 minutes for process conditions
and 5 minutes for standby conditions. Take into account the tube volume and the gas
expansion at high temperatures. For example flows see
Table 3-1, and keep in mind that at
1000
o
C a gas expands 4.7x (and 3.6x at 700
o
C)
- use a flat temperature
The flat temperature is sufficient for most atmospheric processes anyway (especially (dry and wet)
oxidations). A ramped temperature can be used later to counter the expected depletion effects that
will occur in the POCl
3
deposition and diffusion process.
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).
Table 3-1: Initial gas flows for atmospheric processes
Tube
length
[dm]
Tube ID
[dm]
Tube
volume
[liter]
MFC setting
[slm] for
700
o
C 5 min
MFC setting
[slm] for
1000
o
C 3 min
TS430x 13 1.6 26 1.5 1.9
TS460x 18 1.6 36 2.0 2.6
TS480x 20 1.6 40 2.3 2.9
TS4100x 25 1.6 50 2.8 3.6
TS630x 13 2.12 46 2.6 3.3
TS660x 18 2.12 64 3.6 4.5
TS680x 20 2.12 71 4.0 5.0
TS6100x 25 2.12 88 5.0 6.3
TS840x 13 2.7 74 4.2 5.3
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