Chemically Amplified Resist Composition for Polyimide Film Shrinkage

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Solution Overview

Problem

Polyimide resin films used in semiconductor devices face challenges with volume shrinkage during curing, leading to loss of film thickness and dimensional accuracy, and existing positive photosensitive resin compositions lack sufficient sensitivity and resolution for high heat resistance and environmental load reduction.

Innovation Solution

A chemically amplified positive resist composition comprising a polymer with specific recurring units and a siloxane compound as a thermal crosslinker, developed in an alkaline aqueous solution, followed by post-development heat treatment to achieve high heat resistance and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If polyimide precursor is cured at low temperature, then energy consumption is reduced and manufacturing cost is lowered, but the cured film becomes brittle and physical properties are degraded due to incomplete imidization

Engineering Contradiction:

Improvecuring energy consumptionVSAvoidfilm physical properties

Core Design Contradiction:

Use of energy by stationary objectVSReliability

Solution Approach 1:

The patent modifies the chemical structure parameters of the polyimide precursor by introducing specific side chains with imidizable groups that can undergo secondary imidization at low temperatures. This parameter change allows the system to achieve complete imidization and excellent physical properties at lower curing temperatures (80-150°C), resolving the contradiction between energy consumption and film quality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary structural design of the polyimide precursor molecule, pre-positioning imidizable groups in the side chains before the curing process. This preliminary action ensures that the secondary imidization can occur efficiently at low temperatures during curing, eliminating the need for high-temperature treatment while maintaining film performance.

Inventive Principle:

Principle #10Preliminary action

2Temperature

If polyimide resin undergoes cyclo-dehydration curing, then heat resistance is improved, but volume shrinkage occurs leading to loss of film thickness and dimensional accuracy

Engineering Contradiction:

Improveheat resistanceVSAvoidfilm thickness accuracy

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent creates a composite molecular structure combining polyimide backbone with side chains containing imidizable groups. This composite structure enables dual functionality: the polyimide provides heat resistance while the side chain imidizable groups undergo secondary imidization to compensate for volume shrinkage, maintaining film thickness accuracy during curing.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the polyimide resin by incorporating specific imidizable groups in side chains. This parameter modification allows the material to undergo secondary imidization reactions that counteract the volume shrinkage inherent in conventional cyclo-dehydration curing, preserving dimensional accuracy while achieving heat resistance.

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If positive photosensitive resin composition is developed in alkaline aqueous solution for environmental load reduction, then environmental friendliness is improved, but sensitivity and resolution are insufficient

Engineering Contradiction:

Improveenvironmental loadVSAvoidpattern resolution

Core Design Contradiction:

Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The patent modifies the chemical parameters of the resin composition by incorporating polyimide precursors with specific imidizable groups and controlling molecular weight and composition ratios. These parameter changes enhance the photoacidity and chemical reactivity of the system, enabling high sensitivity and resolution patterns to be formed through alkaline aqueous solution development, thus resolving the contradiction between environmental friendliness and pattern quality.

Inventive Principle:

Principle #35Parameter changes

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 composition enables the formation of a thick film with high sensitivity, resolution, and heat resistance, addressing the issues of volume shrinkage and sensitivity in polyimide resin films, while also reducing environmental load.

Implementation Method 1

chemically amplified positive resist composition comprising (A) a base resin, (B) a photoacid generator

Methodology Applied

Scientific EffectPhotoacid generator reaction: Photopolymerisation

Implementation Method 2

thermal crosslinker, and (D) an organic solvent... followed by post-development heat treatment to achieve high heat resistance

Methodology Applied

Scientific EffectThermal crosslinking: Chemical Bonding

Data Source

PatentUS9017905B2Chemically amplified positive resist composition and pattern forming process

Publication Date: 2015.04.28 SHIN ETSU CHEMICAL CO LTD

AI summary

In a chemically amplified positive resist composition comprising (A) a base resin, (B) a photoacid generator, (C) a thermal crosslinker, and (D) an organic solvent, the base resin is a specific polymer and the crosslinker is a siloxane compound. A coating of the composition is readily developable in aqueous alkaline solution. On heat treatment, it forms a cured resist pattern film of satisfactory profile.