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Center of MicroNanoTechnology CMi

Suss Microtec SB6 substrate bonder

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Precautions and Warnings

Processing is restricted only to 100mm wafer to wafer assembling.

Wafer cleaning: The surface of wafers processed in the SB6 tool should be cleaned as best as possible. Having a smooth, particle-free, defect-free surface is extremely important to achieve reliable and good bonding results. The risk of breaking wafers is high is the wafers are not cleaned properly.

Cross-Contamination: The SB6 pressure plates are consumables that are changed based on the type of bonding method to avoid cross-contamination. Make sure to correctly indicate your bonding type when booking the tool, and respect the configuration planning.

Table of content:

  1. Introduction
  2. Equipment Description
  3. User Manual
  4. Links

I. Introduction

The substrate bonder SB6 from Suss Microtec is a dedicated tool for voltage assisted (anodic) bonding of borofloat glass to silicon: A stack of two wafers (or more) is maintained aligned in a vaccum chamber during the following sequence: chamber purging with N2, chamber pumping (optional), heating of the bonding plates, application of pressure and electric field between the two substrates, cooling down.

In addition, the tool can also be configured for other bonding methods, which do not require an electric field such as eutectic bonding (metal interlayer) or adhesive/glue bonding (parylene, polymer interlayer).

II. Equipment Description

The tool consists in:

Original recipes were extended to many methods of wafer to wafer bonding but optimization of recipes other than the original anodic bonding is not trivial. Mainly, residual alignment shifts are observed depending on the intermediate layer thermo-mechanical properties.

The SB6 tool is not adapted for direct wafer to wafer bonding (fusion bonding). Tool pressure and temperature settings/uniformity are not in the correct range for this kind of process.

Fixture description

The fixture consists of 3 x 120 deg. clamp and spacer units, which are pneumatically activated during processing in the chamber.

Top view of the wafer fixture tool (without wafers) with spacers/clamps shown open near wafer support tabs (3 x 120 deg).

Bottom electrode will fit in the central hole just after loading.

N.B. An additional side electrode can be used for tripple stack bonding (on the left of image), e.g. Glass/Si/Glass or SOI to Glass. Ask the staff for guidance!

SB6 wafer Fixture

Top plate description

The top pressure plates comes in two different types: plate with center hole for optimized anodic bonding (central electrode), or full plate for other bonding methods.

The default top plate has a hole in the center to make room for the central electrode, initiating the anodic process in the center of the wafer stack. It can also be used with other bonding methods to reduce residual alignment shift during heating/pressure process steps.

The modified top plate is full and is used with methods other athan anodic to improve pressure and temperature uniformity in the center.

 

SB6 wafer Fiixature

Wafer material and cross-contamination

Authorized material are (d=100mm) silicon and/or borofloat 33 (pyrex) wafers. Other type of fused quartz or glass wafers will break during the process due to thermal mismatch with silicon.
Cross-contamination risks are reduced by changing both bottom and top heater/pressure plates for each type of configuration. This change of configuration need careful attention for correct distance and leveling of the bottom plate. This operation is performed daily only by the CMi lithography staff.

Available configurations are:

A_T350_480 Anodic bonding standard
G_T70 _175 Glue bonding low temperature (SU8 etc...)
G_T220 _340 Glue bonding high temperature (Polymères)
Eutectic T410_450 Eutectic bonding (Au-Si)
Parylene T350 Parylene

Make sure to use your CMi equipment booking interface to reserve the correct configuration (use the "Reservation and config. request" button)

III. User Manual

IV. Links