Pressure Sensitive Adhesive Tape for Semiconductor Back Side Grinding
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Solution Overview
Problem
Pressure sensitive adhesive tapes used in semiconductor processing, such as those for DBG and LDBG, often cause chipping or breakage of chips when they are thinned to 30 μm or less due to compressive and shear stresses during back side grinding, leading to increased chip crack occurrences.
Innovation Solution
A pressure sensitive adhesive tape with a base having a Young's modulus of 1000 MPa or more and a pressure sensitive adhesive layer with specific elastic modulus and creep properties, designed to resist deformation and ensure adequate contact with uneven wafer surfaces, thereby reducing chip vibration and collision during grinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensitive adhesive tape is used for back side grinding of semiconductor wafers, then the wafer surface is protected and the wafer is retained, but chip chipping or breakage occurs when chips are thinned to 30 μm or less due to compressive and shear stresses
Solution Approach 1:
The patent changes the physical parameters of the adhesive tape by specifying a Young's modulus of 1000 MPa or more for the base and controlling the pressure sensitive adhesive layer thickness to 50 μm or less. These parameter changes enable the tape to resist compressive and shear stresses during back side grinding, preventing chip chipping and breakage while maintaining reliability.
Solution Approach 2:
The patent employs a composite structure consisting of a base with specific mechanical properties (Young's modulus ≥1000 MPa) and a pressure sensitive adhesive layer with controlled thickness (≤50 μm). This composite material design provides both the structural support needed to resist stresses and the adhesiveness required to retain the wafer, resolving the contradiction between protection and stress-induced damage.
2Stability of the object's composition
If the pressure sensitive adhesive layer is made thinner to reduce deformation, then stress resistance improves, but contact with uneven wafer surfaces becomes inadequate
Solution Approach 1:
The patent optimizes the thickness parameter of the pressure sensitive adhesive layer to 50 μm or less, which strikes a balance between reducing deformation under stress and maintaining adequate contact with uneven wafer surfaces. This parameter change enables the adhesive layer to conform to surface irregularities while resisting deformation during grinding.
Solution Approach 2:
The patent applies local quality by having the pressure sensitive adhesive layer adapt to local surface variations on the wafer. The controlled thickness allows the material to deform locally to contact uneven surfaces while maintaining overall structural stability and stress resistance.
3Strength
If a rigid base is used to resist stress, then strength increases, but the tape becomes less adaptable to uneven surfaces
Solution Approach 1:
The patent creates a composite structure where a rigid base (Young's modulus ≥1000 MPa) provides strength and stress resistance, while a separate pressure sensitive adhesive layer (thickness ≤50 μm) provides adaptability to uneven surfaces. The combination of these two materials with different properties resolves the contradiction between rigidity and conformability.
Solution Approach 2:
The patent segments the adhesive tape into distinct functional layers: a rigid base for stress resistance and a compliant pressure sensitive adhesive layer for surface conformity. This segmentation allows each layer to perform its specialized function, with the base providing strength and the adhesive layer providing adaptability to uneven surfaces.
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 tape effectively suppresses chip cracks by maintaining adhesiveness and resisting stress, allowing for the production of thinner semiconductor chips without breakage during back side grinding and subsequent release.
Implementation Method 1
a pressure sensitive adhesive layer with specific elastic modulus and creep properties, designed to resist deformation and ensure adequate contact with uneven wafer surfaces
Implementation Method 2
a base having a Young's modulus of 1000 MPa or more
Data Source
AI summary
A pressure sensitive adhesive tape for semiconductor processing includes a base having a Young's modulus of 1000 MPa or more at 23° C., and a pressure sensitive adhesive layer provided on at least one surface of the base, and the product (N)×(C) of (N) and (C) is 500 or more at 30° C., and 9000 or less at 60° C., where (N) [μm] is a thickness of the pressure sensitive adhesive layer and (C) [μm] is a creep amount.