A Handling Solution for Easy Processing of Thin Glass with TGV

A Handling Solution for Easy Processing of Thin Glass with TGV

Citation

Authors: Shelby F. Nelson, David H. Levy, and Aric B. Shorey
Conference: 2020 IEEE 69th Electronic Components and Technology Conference (ECTC)
Year: 2020 

Keywords

  • No Via Contamination 
  • High-Temperature Compatibility
  • Easy Debonding
  • Thinning and Polishing
  • TGV Metallization

 

Brief

This article describes a new temporary bonding technology, using a thin inorganic adhesive layer, that enables easier integration of thin glass into existing semiconductor fabrication processes.

Summary

This article presents a novel temporary bonding method for processing thin glass substrates, particularly those with through-glass vias (TGVs), in high-volume manufacturing settings. The method addresses the limitations of existing temporary bonding techniques, such as polymeric adhesives, which can contaminate the vias and complicate subsequent processing steps.

The new method utilizes a thin, inorganic adhesive layer to bond the thin glass substrate to a silicon handle wafer. This bond is strong enough to withstand various processing steps, including grinding, polishing, via fill, and CMP, while also allowing for easy debonding after processing without leaving residue. The article emphasizes that the bond strength can be tuned to suit specific processing requirements.

The use of a silicon handle wafer ensures compatibility with existing semiconductor processing equipment. The article highlights several advantages of this method, including:

  • No Via Contamination: The inorganic adhesive does not wick into the TGVs, ensuring clean and reliable via fill processes.
  • High-Temperature Compatibility: The bond can withstand temperatures up to 400°C and above without outgassing, making it suitable for high-temperature processing steps.
  • Easy Debonding: The glass substrate can be easily debonded from the silicon handle using mechanical methods, eliminating the need for costly back-grinding.

The article presents successful demonstrations of the technology, including:

  • Thinning and Polishing: Thinning and polishing of high-purity fused silica wafers from 0.35 mm to 0.18 mm, demonstrating the bond's ability to withstand the stresses of grinding and polishing.
  • TGV Metallization: Metallization of TGV glass wafers with both fully-filled and conformally-plated vias, showcasing the compatibility of the bonding method with various metallization techniques.

The article concludes that this temporary bonding technology presents a viable solution for the high-volume manufacturing of thin glass substrates for various applications, particularly in RF and packaging.

Origin: https://www.mosaicmicro.com/wp-content/uploads/Mosaic_Microsystems_ECTC-2020_Paper.pdf

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