Multilayer Adhesive Sheet UV Separation for Semiconductor Pick-Up
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Die attach films with acrylic ester copolymers exhibit strong bonding strength to the adhesive layer, making it difficult to separate the die attach film from the adhesive layer during the pick-up of semiconductor chips, leading to reduced pick-up efficiency and increased chip flying during the dicing process.
Innovation Solution
A multilayer adhesive sheet comprising a base film, an adhesive layer with a specific composition including a (meth)acrylic ester copolymer, ultraviolet polymerizable compounds, a multifunctional isocyanate curing agent, a photopolymerization initiator, and a silicone polymer, which allows for easy separation of the die attach film from the adhesive layer upon irradiation, enhancing chip pick-up efficiency and reducing chip flying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an acrylic ester copolymer is used as the die attach film material to improve storage stability and film-forming property, then the bonding strength to the adhesive layer becomes excessively strong, but this makes the die attach film difficult to separate from the adhesive layer during chip pick-up, leading to reduced pick-up efficiency
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive layer by incorporating specific components (silicone polymer, photopolymerization initiator, and reactive diluent) to modify the bonding characteristics. This allows the adhesive layer to have controlled separation properties upon UV irradiation while maintaining strong initial bonding, thus resolving the contradiction between storage stability and pick-up efficiency
Solution Approach 2:
The invention replaces the purely mechanical separation process with a photochemical mechanism. By incorporating photopolymerization initiators and reactive diluents, the adhesive layer undergoes controlled chemical changes upon UV irradiation, enabling easy separation of the die attach film without mechanical force, thus solving the pick-up efficiency problem while maintaining bonding strength
2Strength
If the bonding strength between die attach film and adhesive layer is increased to improve chip holding during dicing, then chip flying is reduced, but the separation difficulty during pick-up increases
Solution Approach 1:
The invention makes the bonding characteristics dynamic by introducing UV-responsive components. The adhesive layer transitions from a strong bonding state (before UV irradiation) to an easy separation state (after UV irradiation), allowing the system to adapt its bonding strength according to the process stage, thus resolving the contradiction between holding strength and separation ease
Solution Approach 2:
The invention utilizes a chemical phase transition through photopolymerization. The adhesive layer undergoes a chemical state change upon UV irradiation, transforming from a cohesive bonding state to a separable state, enabling strong initial bonding followed by easy separation, thus resolving the contradiction between strength and separation ease
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 multilayer adhesive sheet improves chip pick-up efficiency, reduces chip flying during dicing, and provides stain resistance to the die attach film, ensuring reliable bonding to the lead frame and other components.
Implementation Method 1
the adhesive that constitutes the adhesive layer contains (A) a (meth)acrylic ester copolymer, (B) an ultraviolet polymerizable compound, (C) a multifunctional isocyanate curing agent, (D) a photopolymerization initiator
Implementation Method 2
the adhesive that constitutes the adhesive layer contains (A) a (meth)acrylic ester copolymer, (B) an ultraviolet polymerizable compound, (C) a multifunctional isocyanate curing agent
Data Source
AI summary
Provided is a multilayer adhesive sheet which enables easy separation between an adhesive layer and a die attach film during the pick-up even in cases where an acrylate ester copolymer is used in the die attach film, thereby making the pick-up work of semiconductor chips after the dicing easy. The multilayer adhesive sheet comprises a base film, an adhesive layer that is disposed on one surface of the base film, and a die attach film that is disposed on an exposed surface of the adhesive layer. The adhesive that constitutes the adhesive layer contains: (A) a (meth)acrylate ester copolymer; (B) an ultraviolet polymerizable compound; (C) a multifunctional isocyanate curing agent; (D) a photopolymerization initiator; and (E) a silicone polymer.