The Plasmatherm 790 is a dual chamber parallel plate tool. The left chamber is configured for reactive ion etching (RIE) while the right chamber is configured for plasma enhanced chemical vapor deposition (PECVD). The RIE chamber is significantly slower than other etchers available in the lab, allowing greater depth control on thin films. The PECVD chamber is also designed to deposit at a lower rate than the GSI PECVD and P5000 PECVD - the smaller building blocks help improve film quality. This tool has almost no material restrictions, allowing a wide variety of processing.
|Material Processed||Si, SiO2|
|Mask Materials||PR, SiO2|
|Gases Used||He, O2, SF6|
|Supported Processes||Supported Processes|
|User Processes||User Processes|
- [2014-09-25] - Added 500 sccm Helium MFC to PECVD chamber.
- Wide variety of materials processed
- Wide variety of gases available
- Generally slower etch rates <1000 Å/min
- RIE Gases
- PECVD Gases
- RIE: 5 - 10 mTorr to 1 Torr
- PECVD: 50 - 500 mTorr to 2 Torr
- PECVD: Heated Platen: 200°C - 350°C
- 400 W 13.56 MHz RF Source
- Up to 3 100 mm (4") wafers
- Pieces don't require mounting
- 1 150 mm (6") wafer
- 2 100 mm (4") wafers
- Several pieces
The Plasmatherm 790 is designated as a metals class tool. Below is a list of approved and restricted materials for the Plasmatherm 790. "Approved" means the material is allowed in the tool under normal circumstances. "Not Allowed" means the material may never be used in the tool. If a material is not listed, it may be possible to use the material under certain conditions. Please contact a tool engineer via the helpdesk ticket system for any material requests or questions.
The right chamber has the same restrictions as the left except polymers (such as photoresist) are not allowed unless their melting temperature is significantly higher then the process temperature (please create a helpdesk ticket for this).
There are several processes for this tool supported by the LNF, which are described in more detail on the Processes page.
In addition to these, this tool has a number of user-created recipes for etching a wide variety of materials. Some of these recipes are documented on LNF User:Plasmatherm 790 User Processes. If you are curious if your material can be processed in this tool, please contact the tool engineers via the helpdesk ticket system.
Standard Operating Procedure
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- Read through the Standard Operating Procedure above.
- Complete the training request form here.
- Create a helpdesk ticket requesting training.
- A tool engineer will schedule a time for initial training.
- Practice with your mentor or another authorized user until you are comfortable with tool operation.
- Complete the SOP quiz here.
- Schedule a checkout session with a tool engineer via the helpdesk ticket system. If this checkout is successful, the engineer will authorize you on the tool.
Every other week a light cleaning is performed on the tool. A 5 min etch with m_si_o_1 is performed on a 4" oxide wafer as a qualification run. The results can be seen below.