Specific Process Knowledge/Etch/DRIE-Pegasus/System-description: Difference between revisions
No edit summary |
|||
| (7 intermediate revisions by the same user not shown) | |||
| Line 2: | Line 2: | ||
<!--Checked for updates on 14/5-2018 - ok/jmli --> | <!--Checked for updates on 14/5-2018 - ok/jmli --> | ||
<!-- Page reviewed 9/8-2022 jmli --> | <!-- Page reviewed 9/8-2022 jmli --> | ||
<!--Checked for updates on 4/9-2025 - ok/jmli --> | |||
== Description of the Bosch process at the DRIE-Pegasus == | == Description of the Bosch process at the DRIE-Pegasus == | ||
| Line 16: | Line 16: | ||
**the ion bombardment driven by the platen power ''first'' removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces) | **the ion bombardment driven by the platen power ''first'' removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces) | ||
**''then'' as the bottom of the structures are opened the etch of silicon itself starts. | **''then'' as the bottom of the structures are opened the etch of silicon itself starts. | ||
[[Image:boostdelay4b.jpg |400x400px|thumb|The etch cycle may be split into three parts, Boost, Delay and Main, where process parameters such as pressure, gas flows or RF powers have different values. The red curve shows the possible characteristics of the platen power. {{ | [[Image:boostdelay4b.jpg |400x400px|thumb|The etch cycle may be split into three parts, Boost, Delay and Main, where process parameters such as pressure, gas flows or RF powers have different values. The red curve shows the possible characteristics of the platen power. {{image1}}]] | ||
Here, it is clear that one can distinguish two phases of the etch cycle; one where the ion bombardment removes the polymer and one where the actual etching of silicon takes place. Considering what process conditions are favorable we realize that | Here, it is clear that one can distinguish two phases of the etch cycle; one where the ion bombardment removes the polymer and one where the actual etching of silicon takes place. Considering what process conditions are favorable we realize that | ||
#the ion bombardment requires a low pressure in order for the ions to have a long mean free path and hence good directionality. Also, a high platen power is required to drive the ion bombardment. | #the ion bombardment requires a low pressure in order for the ions to have a long mean free path and hence good directionality. Also, a high platen power is required to drive the ion bombardment. | ||
| Line 28: | Line 28: | ||
== Processing options on the Pegasus == | == Processing options on the Pegasus == | ||
This section applies to all Pegasus tools. | |||
The Pegasus has a lot of advanced processing options. | The Pegasus has a lot of advanced processing options. | ||
| Line 41: | Line 40: | ||
== Modification of the showerhead== | == Modification of the showerhead== | ||
This section applies to all Pegasus tools. | |||
It is clear that optimizing the Bosch processes on the Pegasus can be done in countless ways. Reducing the cycle time is a very convenient way of getting rid of, or at least reducing, scallops. The faster the process switches the smaller the scallops will be. However, at some point the hardware (MFS's, RF generators, APC valve) cannot keep up with the demand and the process will essentially be continuous causing the Bosch process to break down. In its original setup, the Pegasus had standard processes with cycle durations down to 2 seconds. The hardware on the Pegasus is indeed very fast and allows faster switching. The limiting factor in the Bosch process was identified by Henri Jansen - and we have taken steps to improve this as described below. | It is clear that optimizing the Bosch processes on the Pegasus can be done in countless ways. Reducing the cycle time is a very convenient way of getting rid of, or at least reducing, scallops. The faster the process switches the smaller the scallops will be. However, at some point the hardware (MFS's, RF generators, APC valve) cannot keep up with the demand and the process will essentially be continuous causing the Bosch process to break down. In its original setup, the Pegasus had standard processes with cycle durations down to 2 seconds. The hardware on the Pegasus is indeed very fast and allows faster switching. The limiting factor in the Bosch process was identified by Henri Jansen - and we have taken steps to improve this as described below. | ||
| Line 55: | Line 52: | ||
== RF Matching == | == RF Matching == | ||
=== RF matching in general === | === RF matching in general === | ||
| Line 99: | Line 93: | ||
== The Picoscope == | == The Picoscope == | ||
The process monitoring on Pegasus 1, 2 and 3 has been dramatically improved with the installation of the Picoscope. Click [[Specific Process Knowledge/Etch/DRIE-Pegasus/picoscope|'''HERE''']] to access a page on the Picoscope only. | The process monitoring on Pegasus 1, 2 and 3 has been dramatically improved with the installation of the Picoscope. Click [[Specific Process Knowledge/Etch/DRIE-Pegasus/picoscope|'''HERE''']] to access a page on the Picoscope only. | ||
| Line 106: | Line 98: | ||
== The Claritas endpoint system == | == The Claritas endpoint system == | ||
This section applies to Pegasus 1. Too bad that it is empty so far... | |||