High-temperature, spin-on, bonding compositions for temporary wafer bonding using sliding approach

Abstract

New compositions and methods of using those compositions as bonding compositions are provided. The compositions comprise a polymer dispersed or dissolved in a solvent system, and can be used to bond an active wafer to a carrier wafer or substrate to assist in protecting the active wafer and its active sites during subsequent processing and handling. The compositions form bonding layers that are chemically and thermally resistant, but that can also be softened to allow the wafers to slide apart at the appropriate stage in the fabrication process.

Description

RELATED APPLICATIONS[0001]This application also claims the priority benefit of U.S. Provisional Patent Application No. 60 / 828,572, entitled HIGH-TEMPERATURE SPIN-ON ADHESIVES FOR TEMPORARY WAFER BONDING USING SLIDING APPROACH, filed Oct. 6, 2006, the entire disclosure of which is incorporated by reference herein.GOVERNMENT FUNDING[0002]This invention was made with government support under contract number W911 SR-05-C-0019 awarded by the United States Army Research, Development, and Engineering Command. The United States Government has certain rights in the invention.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The present invention is broadly concerned with novel compositions and methods of using those compositions to form bonding compositions that can support active wafers on a carrier wafer or substrate during wafer thinning and other processing.[0005]2. Description of the Prior Art[0006]Wafer (substrate) thinning has been used to dissipate heat and aid in the e...

AI Technical Summary

Problems solved by technology

Thick substrates cause an increase in capacitance, requiring thicker transmission lines, and, in turn, a larger IC footprint.

This requires longer dry-etch times and produces larger quantities of post-etch residue, thus significantly reducing throughput.

Larger vias also require larger quantities of metallization, which is more costly.

When wafer thickness is reduced to less than 300 μm, it becomes difficult or impossible to maintain control with regard to attachment and handling of the wafer during further thinning and processing.

In some cases, mechanical devices may be made to attach and hold onto thinned wafers, however, they are subject to many problems, especially when processes may vary.

The major drawback with this approach is that the composition must be chemically removed, typically by dissolving in a solvent.

This is very time-consuming, thus reducing throughput.

Furthermore, the use of the solvent adds to the cost and complexity of the process, and it can be hazardous, depending upon the solvent required to dissolve the bonding composition.

First, the tapes have limited thickness uniformity across the active wafer / carrier substrate interface, and this limited uniformity is often inadequate for ultra-thin wafer handling.

Second, the thermal release adhesive softens at such low temperatures that the bonded wafer / carrier substrate stack cannot withstand many typical wafer processing steps that are carried out at higher temperatures.

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