Radiation-Curable Adhesive Tape for Wafer Dicing
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Solution Overview
Problem
Conventional adhesive tapes used in semiconductor wafer dicing and die bonding face challenges with adhesion reliability and peeling performance, leading to increased pickup failure ratios and poor yield due to low adhesion strength and viscosity of the adhesive layer, as well as difficulties in controlling peeling ability between the dicing tape and die-bonding adhesive layer.
Innovation Solution
A radiation-curable removable adhesive tape with an acrylic-series copolymer containing carbon-carbon double bonds, hydroxyl groups, and carboxyl groups, having a gel fraction of 60% or greater, is used, which can be combined with a die-bonding adhesive layer to provide enhanced adhesion reliability and controlled peeling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional pressure-sensitive adhesive tape is used for wafer dicing, then the tape can adhere to the wafer, but the adhesive force is insufficient and the tape peels off during dicing
Solution Approach 1:
The patent changes the adhesive parameters by using a radiation-curable adhesive composition that transforms from a low-viscosity coating state to a high-strength cured state. The adhesive contains specific functional groups (carboxyl, hydroxyl, amine) that enable strong bonding to both the wafer and the tape base, while the radiation curing process (UV or electron beam) provides instantaneous crosslinking to achieve sufficient adhesive strength and peeling resistance during dicing operations.
2Reliability
If the adhesive force is increased to prevent peeling during dicing, then adhesion reliability improves, but the peeling capability during chip pickup deteriorates
Solution Approach 1:
The patent implements dynamic adhesive properties through radiation curing. Before curing, the adhesive remains in a low-viscosity state with controlled adhesion for wafer bonding. After radiation exposure, the adhesive undergoes crosslinking transformation, dynamically changing its mechanical properties to achieve strong permanent adhesion. This dynamic state change allows the adhesive to provide sufficient holding force during dicing while enabling clean chip release during pickup through controlled peeling.
Solution Approach 2:
The adhesive undergoes a phase transition from a liquid coating state to a crosslinked solid state through radiation curing. This phase change enables the adhesive to transform its bonding characteristics: in the liquid state, it wets the wafer surface effectively; after curing, it forms a robust crosslinked network that provides strong adhesion reliability while maintaining controlled peeling properties for chip release.
3Reliability
If a laminate of die bonding adhesive layer and dicing tape is used, then adhesion reliability improves, but the peeling ability between dicing tape and die-bonding adhesive layer increases due to heat adhesion
Solution Approach 1:
The patent introduces a radiation-curable adhesive layer as an intermediary between the dicing tape base and the wafer surface. This intermediary layer contains specific functional groups that provide strong bonding to both substrates while remaining sensitive to radiation curing. The radiation-curable nature allows the adhesive to be activated only when needed, avoiding premature bonding issues and controlling the peeling characteristics between the tape and adhesive layer during the dicing process.
4Ease of operation
If heat treatment is applied to peel surface protective tape, then the protective tape can be removed, but the peeling force between die bonding adhesive layer and dicing tape increases
Solution Approach 1:
The patent replaces the thermal activation mechanism with a radiation-based curing system. Instead of using heat treatment to control adhesive activation and peeling, the invention uses radiation (UV or electron beam) to cure the adhesive layer. This substitution eliminates the thermal effects that cause unwanted peeling between layers, as radiation curing occurs instantaneously and locally without generating the sustained heat that would increase peeling forces in laminate structures.
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 ensures reliable adhesion during dicing and easy removal of the adhesive layer after radiation curing, maintaining sufficient adhesion strength between the chip and substrate, while reducing peeling forces and improving storage stability, thus enabling direct die bonding and efficient semiconductor wafer processing.
Implementation Method 1
a radiation-curable removable adhesive layer on a surface of a base, wherein the radiation-curable removable adhesive layer is mainly composed of an acrylic-series copolymer having, in a principal chain, at least a radiation-curable carbon-carbon double bond containing group
Data Source
AI summary
A wafer-adhering adhesive tape, which has, on a surface of a base, a radiation-curable removable adhesive layer, and if necessary a die-bonding adhesive layer in order, wherein the radiation-curable removable adhesive layer is mainly composed of an acrylic-series copolymer having, in a principal chain, at least a radiation-curable carbon-carbon double bond containing group, a hydroxyl group, and a group containing a carboxyl group, respectively, and the radiation-curable removable adhesive layer has a gel fraction of 60% or greater.