Here is the abstract you requested from the nano_2012 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Glass Wafers as Support Carriers for 3D-IC Wafer Thinning Processes|
|Keywords: Glass, Wafers, Carrier|
|As the industry strives to reduce the thickness of silicon device wafers to enable 3D-IC, carrier wafers are required for mechanical support during thinning operations. Non-uniformities in the carrier directly impact the accuracy of the silicon wafer’s total thickness variation (TTV). Other important requirements include excellent flatness and thickness uniformity, and low warp. Not only is it important that the carrier wafer have these characteristics, but suitable metrology must be available for accurate characterization. We will demonstrate that glass has many attributes that make it a good candidate for use as a carrier substrate. Even though the mechanics of failure differ greatly between crystalline materials (Si) and amorphous materials (glass), data shows that the strength of a glass wafer compares favorably to that of a silicon wafer. Also, glass manufacturing processes allow for opportunities to adjust properties such as the coefficient of thermal expansion (CTE) to better manage wafer stack deformation during processing. Optical transparency allows easy inspection of the bond layer and the use of advanced low temperature de-bonding techniques. In order to provide wafers with very low TTV and warp, there must be a method available to characterize wafers in an accurate and repeatable manner. The Tropel® Flatmaster® MSP 300 is a next generation metrology tool able to accurately characterize flatness and TTV to very high precision. Measurement results for precision glass carriers and how quality impacts total stack TTV will be presented.|
|Aric Shorey, Sr. Technical Manager