Antistatic Layer for Surface Protective Sheet
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Solution Overview
Problem
Existing surface protective sheets for semiconductor wafers face challenges in achieving high antistatic performance while preventing crack generation in the antistatic layer, which affects the wafer's warpage and appearance.
Innovation Solution
A substrate for surface protective sheets is developed, incorporating a urethane acrylate oligomer as a curing component in the antistatic layer-forming composition with a high content of metal filler, specifically phosphorus-doped tin oxide, to enhance stress relaxation and antistatic performance, thereby preventing crack generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the addition amount of metal salt antistatic agent is increased to improve antistatic performance, then antistatic performance is improved, but film rigidity is worsened and metal ions move into the pressure sensitive adhesive and front face circuit
Solution Approach 1:
The patent extracts the harmful metal salt antistatic agent from the pressure sensitive adhesive layer and relocates it to a separate antistatic layer. This separation allows the metal salt antistatic agent to provide antistatic performance without compromising the rigidity and purity of the pressure sensitive adhesive layer, preventing metal ion migration into the adhesive and circuit.
Solution Approach 2:
The patent segments the functional layers by providing a distinct antistatic layer separate from the pressure sensitive adhesive layer. This segmentation enables each layer to perform its specific function independently - the antistatic layer handles electrostatic dissipation while the pressure sensitive adhesive layer maintains its bonding properties without contamination.
2Stability of the object's composition
If a substrate with high stress relaxation characteristics is used to prevent wafer warpage, then stress relaxation is improved, but crack generation in the antistatic layer occurs
Solution Approach 1:
The patent employs composite materials in the antistatic layer by combining metal salt antistatic agent particles with a binder resin matrix. This composite structure allows the antistatic layer to achieve both high stress relaxation characteristics and crack resistance, as the binder resin provides flexibility and adhesion while the metal salt particles provide electrostatic dissipation.
Solution Approach 2:
The patent changes the material parameters of the antistatic layer by carefully selecting the binder resin type and controlling the composition ratio between the metal salt antistatic agent and binder resin. These parameter adjustments enable the antistatic layer to maintain integrity under stress relaxation conditions without cracking.
3Adaptability or versatility
If conductive polymer or quaternary amine salt monomer is used as antistatic agent, then antistatic function is provided, but high antistatic performance is hardly achieved
Solution Approach 1:
The patent uses metal salt antistatic agents (such as lithium salts, alkaline earth metal salts, or aluminum salts) which provide superior and more stable antistatic performance compared to conductive polymers or quaternary amine salts. These metal salt-based antistatic layers offer higher reliability and more consistent electrostatic dissipation properties.
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 effectively inhibits crack formation in the antistatic layer, ensuring high antistatic performance and preventing warpage of the wafer, even with high stress relaxation characteristics.
Implementation Method 1
a conductive tin oxide powder having excellent conductivity can be utilized as an antistatic agent
Implementation Method 2
by using a urethane acrylate oligomer as a curing component of an antistatic layer-forming composition
Implementation Method 3
a stress relaxation rate of the substrate for surface protective sheet is 60% or more
Data Source
AI summary
The substrate for surface protective sheet of the present invention is a substrate for surface protective sheet including a support film and an antistatic layer provided on one face of the support film, wherein a stress relaxation rate of the substrate for surface protective sheet is 60% or more; the antistatic layer is one formed by curing an antistatic layer-forming composition containing a curing component and a metal filler; and the content of a metal filler is 55 mass % or more relative to the total mass of the curing component and the metal filler, and the curing component includes a urethane acrylate oligomer.