Radiation-Curable Adhesive for Semiconductor Wafer Dicing
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Solution Overview
Problem
The challenge in semiconductor wafer dicing is to achieve a balance between strong adhesive properties for retention and easy peeling without causing damage during the pick-up process, especially with the increasing risk of deformation due to reduced thickness and weight of semiconductor products.
Innovation Solution
A radiation-curable adhesive composition with a base polymer comprising structural units from monomers A, B, and C, where monomer B is a methacrylate with an alkyl group of 10-17 carbon atoms, and monomer C introduces polymerizable carbon-carbon double bonds, allowing for controlled glass transition temperature and adhesive properties, enabling a gentle peeling operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the adhesive sheet is used to protect and fix the semiconductor wafer during dicing, then strong adhesive performance is achieved, but peeling becomes difficult and may cause damage to the wafer
Solution Approach 1:
The adhesive composition changes its properties through radiation curing. Before curing, the adhesive has strong adhesive characteristics for secure attachment. After radiation exposure, the adhesive characteristics are reduced, enabling easy peeling. This parameter change allows the same adhesive to provide both strong bonding and easy removal at different stages.
Solution Approach 2:
The adhesive sheet is pre-cured with radiation before the pick-up operation. This preliminary curing action reduces the adhesive characteristics in advance, preparing the adhesive layer for easy peeling during the subsequent pick-up operation without causing damage to the semiconductor wafer.
2Ease of operation
If the adhesive sheet is stretched and lifted during expanding step, then peeling of semiconductor chip is facilitated, but deformation and damage risk increases due to reduced thickness and weight
Solution Approach 1:
Radiation curing changes the adhesive's mechanical properties, making it more compliant and less prone to causing deformation. The cured adhesive layer has modified viscoelastic properties that reduce stress concentration on the thin semiconductor wafer during the expanding and pick-up operations.
Solution Approach 2:
The adhesive composition uses a base polymer with specific monomers (including methacrylate monomers with 10-17 carbon atoms) that create a composite adhesive structure. This composite structure provides both adequate adhesion strength and improved mechanical compliance to protect the fragile semiconductor wafer during handling.
3Ease of operation
If radiation is applied to reduce adhesive characteristics for peeling, then ease of peeling is improved, but adhesive strength is reduced
Solution Approach 1:
The adhesive layer is pre-cured with radiation before the pick-up operation. This preliminary action reduces the adhesive characteristics in advance, preparing the adhesive layer for easy peeling during the subsequent pick-up operation without causing damage to the semiconductor wafer.
Solution Approach 2:
The adhesive composition exhibits dynamic properties that change with radiation exposure. Before radiation, it provides strong adhesive force. After radiation exposure, the adhesive characteristics are reduced, enabling easy peeling. This dynamic transformation allows the adhesive to adapt its properties to different operational requirements.
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 adhesive composition ensures enhanced pick-up of semiconductor chips with minimal raising, reducing the risk of damage and maintaining strong adhesive properties before irradiation, while facilitating easy peeling post-irradiation, thus preventing unintended peeling and improving dicing efficiency.
Implementation Method 1
a base polymer as a principal base material, the base polymer includes structural units derived from at least a monomer A that has a functional group a; a monomer B that is formed from a methacrylate monomer that has an alkyl group that includes at least 10 and no more than 17 carbon atoms; and a monomer C that has both a functional group c that reacts with the functional group a and a polymerizable carbon-carbon double bond group
Data Source
AI summary
The present invention provides a radiation-curable adhesive composition having a base polymer as a principal base material, the base polymer includes structural units derived from at least a monomer A that has a functional group a; a monomer B that is formed from a methacrylate monomer that has an alkyl group that includes at least 10 and no more than 17 carbon atoms; and a monomer C that has both a functional group c that reacts with the functional group a and a polymerizable carbon-carbon double bond group, and a main chain of the base polymer is configured from the monomer B and the monomer A, the proportion of the monomer B being at least 50 wt% of the total monomers configuring the main chain; and the base polymer includes a polymerizable carbon-carbon double bond group in a side chain as a result of a portion of the functional group a in the monomer A reacting and bonding with the functional group c in the monomer C.