Tousimis 915B Critical Point Dryer

Tousimis 915B Critical Point Dryer
Equipment Details
Technology	Release
Materials Restriction	Metals
Sample Size	Pieces up to 150 mm (6")
Gases Used	CO2
Equipment Manual
Overview	System Overview
Operating Procedure	SOP
Maintenance	Maintenance

The Tousimis Automegasamdri 915B is a critical point dryer designed to remove liquids from devices while avoiding surface tension that can either hinder complete drying or rip apart delicate MEMs devices. The water and other liquids are displaced using methanol and then the methanol is washed away using liquid Carbon Dioxide at a high pressure. The CO₂ is then heated under pressure to above it’s critical point (31.1°C at 1072 psi) where it becomes a supercritical fluid and can be bled off as gas to avoid all the stresses from surface tension inherent in the transition from liquid to gas.

Announcements

• Needs detailed SOP - expect soon

Capabilities

• Critical Point Drier
  • Uses pressurized CO₂ to dry samples with no surface tension
  • Can run a variety of sample sizes

System Overview

Hardware details

• High-Pressure CO₂ chamber
  • Automatic sequence of controlled valve actuation to set pressure, purging, cooling and heating
  • Variable needle valves to control rates of CO₂ introduction
  • Chamber runs -6°C to 40°C through cool gas introduction and a lamp heater
  • Pressures 0-1400 psi with safety check valves

Substrate requirements

• 6" wafers or smaller pieces
• Thicker substrates discouraged

Material restrictions

The Tousimis 915B Critical Point Dryer is designated as a Metals class tool. Below is a list of approved materials for the tool. Approved means the material is allowed in the tool under normal circumstances. If a material is not listed, please create a helpdesk ticket or email info@lnf.umich.edu for any material requests or questions.

Approved materials

Supported processes

Critical Point Drying sequence set by process controller. Only needle valve settings and purge time are changeable. Recommended needle valve and purge time settings are outlined in the SOP and the 1-page summary.

Standard operating procedure

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Checkout procedure

• Read through this page and the Standard Operating Procedure above.
• Create a Helpdesk Ticket requesting training.
• A tool engineer will schedule a time for initial training.
• Practice with another authorized user or staff until you are comfortable with tool operation.
• 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.

Maintenance

CO₂ cylinders are replaced when they get below 20 lbs of gas. Tare weight and full tank weights can be taken from the tank replacement log on the service aisle door.

Power Bump Recovery

The tool is kept off when not in use so there is nothing to do during a power bump.