Polyimide Photoresist Copolymers for Semiconductor Pattern Resolution

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Solution Overview

Problem

Conventional polyimide photoresists suffer from film reduction and swelling during fine pattern formation, and have poor solubility in alkaline developers, which limits their resolution and mechanical properties in semiconductor device fabrication.

Innovation Solution

The use of polyimide-based polymers and copolymers containing dianhydride moieties, such as polyimide, polyamic acid, and polyamic ester, as binder resins in photoresist compositions, which are designed to provide high resolution, sensitivity, and improved mechanical properties while maintaining appropriate solubility in alkaline developers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional polyimide photoresists are used for fine pattern formation, then the process is simple, but film reduction and swelling occur leading to poor resolution

Engineering Contradiction:

Improvepattern resolutionVSAvoidfilm dimensional stability

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical structure of polyimide polymers by incorporating specific dianhydride moieties (such as 3,4-dicarboxy-1,2,3,4-tetrahydro-6-tert-butyl-1-naphthalene succinic dianhydride) and diamine components to alter solubility parameters and thermal properties, thereby reducing film reduction and swelling during pattern formation while maintaining manufacturing simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses copolymer compositions combining different polyimide segments with distinct functional properties - one segment providing thermal stability and another providing controlled solubility in alkaline developers - to achieve both dimensional stability and pattern resolution in the photoresist film

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional polyimide photoresists are used, then thermal stability is good, but solubility in alkaline developers is poor limiting sensitivity

Engineering Contradiction:

Improvethermal stabilityVSAvoidpattern sensitivity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces localized functional groups (such as carboxylic acid groups from dianhydride moieties and hydroxyl groups from diamine components) at specific positions in the polymer chain to create regions of enhanced alkaline solubility while maintaining the overall thermal stability provided by the polyimide backbone structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention adjusts the chemical composition parameters by controlling the molar ratios of different dianhydride and diamine components to optimize the balance between thermal stability (maintained by aromatic rings and imide groups) and alkaline developer solubility (enhanced by carboxylic acid and hydroxyl groups), thereby improving pattern sensitivity

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8669038B2Polyimide-based polymers, copolymers thereof and positive type photoresist compositions comprising the same

Publication Date: 2014.03.11 LG CHEM LTD

AI summary

Polyimide-based polymers and copolymers thereof are provided. Further provided is a positive type photoresist composition comprising at least one of the polyimide-based polymers and copolymers thereof as a binder resin. The photoresist composition exhibits high resolution, high sensitivity, excellent film characteristics and improved mechanical properties, which are required for the formation of semiconductor buffer coatings.