Back-Grinding Adhesive Sheet With Opening for Convex Wafer Protection
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Solution Overview
Problem
Adhesive sheets for semiconductor wafers face issues with peeling from the base material layer, leading to difficulties in back grinding, especially when corona discharge treatment is applied only to the area where the adhesive layer is formed, reducing productivity and causing adhesion problems.
Innovation Solution
An adhesive sheet with a base material layer comprising a cushion layer and a surface treatment layer, where the surface treatment layer is formed of an acrylic resin composition cross-linked by light irradiation or heating, and the adhesive layer is also made of an acrylic resin composition, ensuring strong adhesion without the need for corona discharge treatment, and is designed with an opening part to accommodate convex parts on the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If corona discharge treatment is applied to the base material layer to improve adhesion between the adhesive layer and base material layer, then peeling resistance is improved, but the wafer becomes strongly adhered to the base material layer causing difficulty in peeling
Solution Approach 1:
The base material layer is divided into two functional layers: a cushion layer (first layer) that provides strong adhesion through corona discharge treatment to prevent adhesive layer peeling, and a surface treatment layer (second layer) that provides controlled adhesion to the wafer. This segmentation allows different regions of the base material layer to have different adhesion characteristics, resolving the contradiction between preventing adhesive layer peeling and enabling easy wafer removal.
Solution Approach 2:
Different layers of the base material layer are given different local qualities: the cushion layer has high adhesion quality (corona discharge treated) to bond with the adhesive layer, while the surface treatment layer has controlled adhesion quality to allow easy wafer peeling. This local differentiation of properties enables the base material layer to simultaneously satisfy conflicting adhesion requirements.
2Reliability
If the adhesive layer is made thick to improve followability of uneven pattern surface, then bump followability is improved, but adhesive residue risk increases
Solution Approach 1:
The adhesive system is segmented into an adhesive layer and a surface treatment layer with distinct functions. The adhesive layer provides followability for uneven surfaces, while the surface treatment layer controls adhesion strength to prevent residue. This functional segmentation allows optimization of each layer for its specific purpose without compromising the other.
Solution Approach 2:
The adhesive sheet uses a composite structure with an adhesive layer (providing followability) and a surface treatment layer (providing controlled adhesion). This composite material approach combines the benefits of thick adhesive for followability with a separate layer that prevents adhesive residue, resolving the contradiction between these two requirements.
3Reliability
If corona discharge treatment is applied only to the area where adhesive layer is formed, then adhesion is improved, but productivity is significantly reduced
Solution Approach 1:
The cushion layer is pre-treated with corona discharge across its entire surface before the adhesive layer is applied. This preliminary action ensures uniform adhesion enhancement across the entire base material layer, eliminating the need for subsequent selective treatment and maintaining high manufacturing productivity while ensuring reliable adhesion.
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 provides improved adhesion between the adhesive layer and the base material layer, reducing peeling issues and allowing easy separation of the wafer from the adhesive sheet, while maintaining followability and protecting the wafer surface.
Implementation Method 1
the surface treatment layer is formed of an acrylic resin composition containing an acrylic resin; the acrylic resin is cross-linked by light irradiation or heating
Implementation Method 2
the adhesive layer is adhered to an outer peripheral part of the semiconductor wafer
Data Source
AI summary
The present invention aims to provide an adhesive sheet for back grinding capable of suppressing peeling of an adhesive layer and capable of peeling a wafer easily from an adhesive sheet.According to the present invention, provided is an adhesive sheet for back grinding of a semiconductor wafer having a convex part, comprising: a base material layer; and an adhesive layer provided on the base material layer, wherein: the adhesive layer comprises an opening part having a diameter smaller than a diameter of the semiconductor wafer; the adhesive layer is adhered to an outer peripheral part of the semiconductor wafer so shat the convex part of the semiconductor wafer is placed in the opening part; the adhesive layer is configured so that the convex part is protected by the base material layer with the semiconductor wafer adhered to the adhesive layer; the base material layer comprises a cushion layer and a surface treatment layer provided thereon; the adhesive layer is provided on the surface treatment layer; the surface treatment layer is formed of an acrylic resin composition containing an acrylic resin; the acrylic resin is cross-linked by light irradiation or heating; and the adhesive layer is formed of an acrylic resin composition containing an acrylic resin.