Resin Sheet with Surface Irregularities for Wafer Fixation
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Solution Overview
Problem
The existing methods for processing wafers often result in adhesive residue remaining on the wafer surface after removing the resin sheet, particularly when using strong adhesives for wafers with bumps or those to be divided into small device chips, which complicates the processing and cleaning procedures.
Innovation Solution
A method involving a resin sheet with a layered structure, including an adhesive layer and a base material layer, where surface irregularities are formed on the base material layer opposite the adhesive layer, allowing the wafer to be fixed to the resin sheet without using adhesive, thereby preventing residue from remaining on the wafer during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin sheet with strong adhesive is used to firmly secure the wafer, then the fixation reliability is improved, but adhesive residue remains on the wafer surface after removing the resin sheet
Solution Approach 1:
The adhesive layer is extracted from the resin sheet structure that contacts the wafer. The resin sheet comprises a base material layer and an adhesive layer, where only the base material layer contacts the wafer surface, while the adhesive layer is positioned between the base material layer and support base. This extraction eliminates adhesive residue on the wafer while maintaining fixation through suction holes in the base material layer.
Solution Approach 2:
The base material layer of the resin sheet is made porous by forming suction holes that extend from one surface to the other. These suction holes enable the resin sheet to be held on a chuck table through vacuum suction, providing reliable fixation without requiring adhesive on the wafer-contacting surface.
2Strength
If adhesive is used to secure the resin sheet to the wafer, then the fixation strength is improved, but the processing complexity increases due to cleaning requirements
Solution Approach 1:
The adhesive is extracted from the wafer-contacting interface and relocated to the internal structure of the resin sheet. The adhesive layer is positioned between the base material layer and support base, eliminating the need for wafer cleaning operations while maintaining strong fixation through the suction mechanism.
Solution Approach 2:
The chemical bonding mechanism (adhesive) is replaced with a mechanical fixation mechanism (suction through porous holes). The resin sheet is held on the chuck table through vacuum pressure applied to the suction holes, providing secure fixation without chemical residues that would complicate processing.
3Reliability
If a resin sheet with adhesive layer is used to protect the wafer face side, then the protection function is improved, but the cost increases due to additional adhesive materials
Solution Approach 1:
The adhesive layer is extracted from the necessary functional components and repositioned to the internal structure of the resin sheet. The base material layer alone contacts the wafer to provide protection, while the adhesive layer serves only to bond the base material layer to the support base, eliminating unnecessary adhesive consumption.
Solution Approach 2:
The base material layer serves multiple functions: it protects the wafer face side during processing and simultaneously provides structural support with integrated suction holes for fixation. This multi-functionality eliminates the need for separate adhesive materials on the wafer surface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures that no adhesive remains on the wafer when peeled off, simplifies the processing and cleaning steps, and allows for effective fixation and handling of wafers with bumps or small device chips, while also enabling the use of the resin sheet as a protective tape without additional adhesive costs.
Implementation Method 1
forming surface irregularities on a face side of the base material layer that is opposite the adhesive layer
Implementation Method 2
holding a surface of the support base that is opposite the resin sheet, with the workpiece being fixed to the support base through the resin sheet, on a holding surface of a rotatable chuck table
Implementation Method 3
grinding the reverse side of the workpiece with a grinding stone mounted on a grinding wheel disposed in facing relation to the holding surface
Implementation Method 4
polishing the reverse side of the workpiece with a polishing pad disposed in facing relation to the holding surface
Data Source
AI summary
A method of processing a workpiece includes sticking an adhesive layer side of a resin sheet having a layered structure that includes the adhesive layer and a base material layer, to a support base, forming surface irregularities on a face side of the base material layer that is opposite the adhesive layer; placing a face side of the workpiece and the face side of the base material layer in facing relation to each other and pressing the workpiece against the resin sheet or pressing the resin sheet against the workpiece, thereby bringing the workpiece into intimate contact with the resin sheet to fix the workpiece to the resin sheet; holding a surface of the support base that is opposite the resin sheet on a holding surface of a chuck table, and grinding a reverse side of the workpiece with a grinding stone disposed in facing relation to the holding surface.