Fluorine ICP Etcher (PlasmaTherm/SLR Fluorine ICP)

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Fluorine ICP Etcher (PlasmaTherm/SLR Fluorine ICP)
Location Bay 2
Tool Type Dry Etch
Manufacturer Plasmatherm (Unaxis)
Description SiRIE Based Flourine Etcher for Bosch MEMS Processes

Primary Supervisor Tony Bosch
(805) 893-3486

Secondary Supervisor

Aidan Hopkins

Recipes Dry Etch RecipesN/A

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The system is a Plasma-Therm 770 SLR series system with a loadlock, dedicated to fluorine-based gases (system aka. "FL-ICP"). The system has an Inductively Coupled Plasma (ICP) coil and a capactively coupled substrate RF supply to independently control plasma density and ion energy in the system. Helium back-side cooling is available to keep the sample cool during the etch. The system is fully computer controlled in all aspects of the pumping cycles and process control, and can be programmed by the user.

The system is generally meant for any fluorine-containing etch, which is typically for etching materials like SiO2, Si3N4, Silicon, or other materials with volatile fluoride etch products.

The fixturing is configured for 4" diameter Si wafers and uses a ceramic clamp on the outer ~5mm of the 100mm wafer to hold the sample on the RF chuck.

Smaller samples can be mounted onto 100mm carrier wafers, either with no adhesive (sample temperature will be higher), or with Santovac oil for better thermal cooling. However, great care must be taken to ensure no oil, photoresist or small pieces are placed on the outer 5mm of the carrier wafer, as the ceramic clamp will physically press on this outer region, potentially causing stiction or wafer breakage if foreign or sticky substances are in those regions.

The in-situ laser monitor installed on the chamber allows for repeatable etches and endpoint detection via continuous optical monitoring of the wafer reflectivity in a user-determined location, through a porthole on the chamber.

Detailed Specifications

  • 1000 W ICP coil power at 2 MHz and 500 W substrate bias at 13.56 MHz plasma generators
  • C4F8, SF6, O2, Ar, N2, CHF3, CF4 gases available
  • He-back-side cooling
  • Single 100mm/4-inch wafer handling with physical topside clamp, contacting outer 5mm of wafer.
    • Small samples may be mounted with oil or no adhesive, but must be far away from this 5mm edge exclusion zone.
    • No photoresist or oil is allowed to contact the clamp, or wafers will get stuck and possibly break in the chamber.
  • Windows-based computer control of process and wafer handling
  • Laser endpoint monitoring with camera and simulation software, for repeatable etching - see: Intellemetrics LEP 500