Adhesive Sheet for Semiconductor Wafer Thinning
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Solution Overview
Problem
Thin semiconductor wafers are prone to breaking and warping during processing due to increased fragility and stress, requiring temporary bonding materials that can withstand high temperatures and multiple usage cycles without leaving residual adhesive.
Innovation Solution
A semiconductor wafer support arrangement with a layer of adhesive having at least 100 gm/25 mm peel strength and 10 psi die shear at 20-50°C, capable of withstanding 200°C for 3 minutes, and releasing without residue, using a substrate that is dimensionally stable and flexible, allowing for repeatable use and easy peeling from the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thin semiconductor wafers are processed, then thermal resistance is reduced and thermal transfer is improved, but the wafers become more fragile and prone to breaking and warping
Solution Approach 1:
A temporary bonding adhesive sheet is introduced as an intermediary between the thin semiconductor wafer and the processing environment. This adhesive sheet provides mechanical support and stabilization to the fragile thin wafer during processing operations, preventing breaking and warping while allowing the wafer to maintain its thin profile for improved thermal performance
Solution Approach 2:
The adhesive sheet's adhesion properties are designed to change with temperature - maintaining strong adhesion at processing temperatures (withstanding 200°C for 3 minutes) to support the wafer, then enabling easy release at lower temperatures or through chemical treatment, thus adapting to different processing stages
2Reliability
If conventional temporary bonding materials are used, then wafer support is provided, but residual adhesive remains on the wafer requiring rinsing or cleaning
Solution Approach 1:
The adhesive sheet is designed with a specific composition and structure that allows the adhesive layer to be completely removed or decomposed after serving its support function. The adhesive can be decomposed through chemical treatment, heat, or mechanical means, extracting the adhesive material from the system and leaving no harmful residues on the wafer surface
Solution Approach 2:
The adhesive material undergoes phase transitions or chemical transformations that enable easy removal. The adhesive may decompose, melt, or change its physical/chemical properties under specific conditions (temperature, chemical exposure), allowing complete removal without leaving residues that would require extensive cleaning
3Temperature
If adhesive strength is increased to withstand high temperature, then wafer support is maintained, but adhesion to substrate becomes too strong for easy release
Solution Approach 1:
The adhesive sheet employs different adhesive layers or compositions with different properties - one layer provides strong adhesion to the substrate to maintain wafer support at high temperatures, while another layer or the same layer under different conditions provides controlled release capability, creating local quality variations in adhesion strength
Solution Approach 2:
The adhesive's bonding characteristics are made dynamic rather than static - the adhesive strength changes based on environmental conditions such as temperature, humidity, or chemical exposure. This allows the adhesive to maintain strong bonding during processing then become easily releasable under different conditions, enabling both strong support and easy release
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
The solution provides strong adhesion to the substrate while minimizing adhesion to the wafer, ensuring zero residual adhesive and maintaining wafer stability during high-temperature processes, enabling multiple usage cycles without the need for rinsing or cleaning.
Implementation Method 1
the wafer supporting adhesive withstands exposure to a temperature of about 200° C. or higher for at least 3 minutes without decomposition
Implementation Method 2
the wafer supporting adhesive outgasses less than about 0.5% by weight under a high vacuum
Implementation Method 3
the wafer supporting adhesive having at least 100 gm/25 mm peel strength and/or at least 10 psi die shear at a temperature of about 20-50° C.
Data Source
AI summary
A semiconductor wafer support arrangement and method for processing a semiconductor wafer including an adhesive sheet may comprise: a layer of wafer supporting adhesive that has certain characteristics that permit wafer processing, e.g., wafer thinning, and removal of the processed wafer in condition for use without cleaning. The carrier or substrate for the wafer processing may be reusable, and the adhesive sheet may have plural layers and may include a flexible substrate.