Pressure-sensitive adhesive sheet for semiconductor processing

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Solution Overview

Problem

Current pressure-sensitive adhesive tapes used in semiconductor processing lack sufficient solvent resistance, particularly when wafers are thinly ground, leading to inadequate protection during solvent washing steps.

Innovation Solution

A pressure-sensitive adhesive sheet with a swelling degree of 2.1 times or less in N,N-dimethylpropionamide solution, containing a base polymer with a high content ratio of esters of acrylic or methacrylic acid with alkyl groups of 8 or more carbon atoms, and optionally including a phosphoric acid ester-based surfactant, providing excellent solvent resistance and maintaining adhesive properties during solvent washing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional pressure-sensitive adhesive tapes are used for protecting semiconductor wafers, then the wafers are protected during conveyance, but the adhesive performance deteriorates during solvent washing steps

Engineering Contradiction:
Improveadhesive performanceVSAvoidsolvent resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the pressure-sensitive adhesive by incorporating specific polymers (polyacrylic acid, polyacrylamide, polyvinyl alcohol, carboxymethyl cellulose, or starch) in controlled amounts (0.1-10 parts by weight per 100 parts by weight of adhesive resin). This compositional parameter change enables the adhesive to maintain its bonding performance while resisting solvent penetration during washing steps, thereby resolving the contradiction between adhesive reliability and solvent resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite pressure-sensitive adhesive system by combining adhesive resins with specific functional polymers and additives. The composite structure includes the base adhesive resin plus water-soluble or water-dispersible polymers that provide solvent resistance, along with optional surfactants and crosslinking agents. This composite material approach allows the adhesive to simultaneously exhibit good adhesion to the wafer and resistance to solvent penetration, resolving the technical contradiction.

Inventive Principle:
Principle #40Composite materials

2Productivity

If wafers are thinly ground for miniaturization and high functionalization, then integration density is improved, but the wafer becomes more brittle and requires stronger protection

Engineering Contradiction:
Improveintegration densityVSAvoidwafer brittleness
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies a pressure-sensitive adhesive tape with enhanced protective properties before the wafer undergoes brittle handling operations. The adhesive composition is specifically designed to provide cushioning and protection during conveyance and processing steps where thin, brittle wafers are vulnerable. This beforehand protection prevents damage to the thinly ground wafers while allowing the high integration density design to be realized.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 adhesive sheet maintains satisfactory adhesive properties and solvent resistance, preventing solvent penetration and ensuring effective protection of thinly ground wafers during semiconductor processing, including solvent washing steps.

Implementation Method 1

The pressure-sensitive adhesive composition has a swelling degree SA of 2.1 times or less when immersed in an N,N-dimethylpropionamide solution at 23° C. for 1 hour

Methodology Applied
Scientific EffectSwelling resistance:

Data Source

PatentUS20240034914A1Pressure-sensitive adhesive sheet for semiconductor processing
Publication Date: 2024.02.01 NITTO DENKO CORP
  • US20240034914A1 patent drawing

AI summary

Provided is a pressure-sensitive adhesive sheet for semiconductor processing having excellent solvent resistance. The pressure-sensitive adhesive sheet for semiconductor processing includes a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing a base polymer, and a base material. The pressure-sensitive adhesive composition has a swelling degree SA of 2.1 times or less when immersed in an N,N-dimethylpropionamide solution at 23° C. for 1 hour.