Plasmatherm 790

Plasmatherm 790
Equipment Details
Technology	RIE
Materials Restriction	Broad
Material Processed	Si, SiO2
Mask Materials	PR, SiO2
Gases Used	Ar, CH4, CHF3, CF4, H2, O2, SF6
Equipment Manual
Overview	System Overview
Operating Procedure	SOP
Supported Processes	Supported Processes
User Processes	User Processes

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.

Capabilities

• Wide variety of materials processed
• Wide variety of gases available
• Generally slower etch rates <1000 Å/min
• Generally slow PECVD deposition rates <10 Å/sec

System Overview

Hardware Details

• RIE Gases
  • Ar - 139 sccm
  • CH₄ - 14 sccm
  • CHF₃ - 50 sccm
  • CF₄ - 42 sccm
  • H₂ - 101 sccm
  • O₂ - 100 sccm
  • SF₆ - 52 sccm
• PECVD Gases
  • CH₄ - 72 sccm
  • CF₄ - 4% O₂ - 420 sccm
  • He - 500 sccm
  • N₂ - 2000 sccm
  • N₂O - 497 sccm
  • NH₃ - 3 sccm
  • SiH₄ - 6 sccm

• Pressure
  • RIE: 1 Torr Guage
  • PECVD: 2 Torr Gauge

• Chuck
  • PECVD: Heated Platen: 200°C - 350°C

• RF
  • 400 W 13.56 MHz RF Source

Substrate Requirements

• RIE
  • Up to 3 100 mm (4") wafers
  • Pieces don't require mounting
• PECVD
  • 1 150 mm (6") wafer
  • 2 100 mm (4") wafers
  • Several pieces

Material Restrictions

A full list of approved materials is included at the end of this section. The materials can be classified into four categories, detailed below. Use of any material outside of these conditions requires approval by the LNF staff via a helpdesk ticket.

• Materials etchedː These materials can be etched in the system, and a recipe is available for them. However, this doesn't mean it is the best-known or recommended method.

• Mask materialsː This includes any material that will be exposed to the plasma for the majority of the process. The most common mask materials are photoresist and silicon dioxide.

• Etch stop materialsː This includes any material that will be exposed briefly to the plasma.

• Buried materialsː These materials may be present on the sample, but may not be exposed to the plasma. They may be covered by the mask or on the back of the sample, provided that the sample is mounted to a carrier wafer.

Below is a list of approved materials for the tool. Approved means the material is allowed in the tool under the classification described above. If a material is not listed, please create a helpdesk ticket or email info@lnf.umich.edu for any material requests or questions.

Right Chamber

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 than the process temperature (please create a helpdesk ticket for this).

Supported Processes

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.

The latest PECVD qualification data is shown below.

Standard Operating Procedure

• System Overview
• RIE SOP
• PECVD SOP
• Troubleshooting

Checkout Procedure

1. Read through the User Manual above.
2. Accurately complete the SOP quiz. You may retake as necessary until all answers are correct.
3. For RIE, complete the process request form.
4. Create a helpdesk ticket requesting a training session.
   1. Find an available time for training here.
5. Schedule a time for a checkout:
   1. Verify that the tool is available in the LNF Online Services at the time you are requesting.
   2. After confirmation that the event is scheduled in the Calendly link provided by the assigned staff member, invite them to a Staff Support reservation at that time.
6. Create a helpdesk ticket for final confirmation of your checkout appointment.
7. Authorization will be provided pending successful completion of the quiz and demonstration of proper tool use in the presence of a tool engineer.