Ring-Opened Protective Film Composition for Wet Etching Masks
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Solution Overview
Problem
Existing protective films for semiconductors during wet etching lack effective mask functionality, high etching rates, and uniformity on stepped substrates, limiting their ability to protect substrates and facilitate efficient processing.
Innovation Solution
A protective film-forming composition comprising a ring-opening polymerization product from a diepoxy compound and a bi- or higher functional proton-generating compound, which forms a film with excellent mask functionality, high dry etching rate, and uniformity on substrates with stepped features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low molecule compound (e.g., gallic acid) is used as an additive to develop resistance to SC-1 wet etching chemical liquid, then the protective film has good mask function to wet etching liquid, but the film has poor covering property on stepped substrates and large difference in film thickness after embedding
Solution Approach 1:
The patent changes the molecular weight parameter of the protective film material from low molecule compound (e.g., gallic acid) to polymer compound (number average molecular weight 1,000-100,000). This parameter change enables the film to simultaneously achieve good mask function and improved covering property on stepped substrates with smaller film thickness differences.
Solution Approach 2:
The patent uses composite material system consisting of polymer compound and crosslinking agent. The polymer compound provides the base film structure with good covering property, while the crosslinking agent enhances the mask function through crosslinking reactions, achieving both requirements simultaneously.
2Reliability
If a protective film is used to protect substrate during wet etching, then the substrate is protected from etching liquid, but the protective film requires high etching rate for quick removal by dry etching to avoid substrate damage
Solution Approach 1:
The patent applies local quality principle by creating a protective film with spatially differentiated properties: the film exhibits high resistance to wet etching liquid where protection is needed, while maintaining high etching rate by oxygen plasma for quick removal. The crosslinking density and composition are optimized to achieve this local differentiation of chemical resistance and etchability.
Solution Approach 2:
The patent changes the chemical composition parameters of the protective film by using specific polymer compounds with particular functional groups and crosslinking agents. These parameter changes enable the film to have selective chemical resistance - high resistance to wet etching chemicals but high reactivity to oxygen plasma for rapid removal.
3Manufacturing precision
If a protective film-forming composition is applied to achieve good covering property on stepped substrates, then the film thickness difference is reduced, but the mask function to wet etching liquid may be compromised
Solution Approach 1:
The patent applies preliminary action by forming a uniform polymer-based protective film on stepped substrates before the actual wet etching process. This preliminary film formation ensures good covering property and uniform thickness, and subsequent crosslinking enhances the mask function, preparing the film to fulfill both requirements before processing begins.
Solution Approach 2:
The patent uses composite material system where polymer compound provides the base film with good covering property and uniform thickness distribution on stepped substrates, while crosslinking agent enhances the mask function. The synergistic combination ensures both film thickness uniformity and effective mask function are achieved.
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 provides a protective film that effectively masks substrates during wet etching, enables rapid dry etching, and ensures flatness on substrates with stepped features, facilitating precise and efficient semiconductor processing.
Implementation Method 1
a ring-opening polymerization product (C) from a reaction of a diepoxy compound (A) and a bi- or higher functional proton-generating compound (B)
Data Source
AI summary
A protective film forming composition forms a flat film having good mask function against a wet etching liquid during a semiconductor substrate processing, high dry etching rate and good coverage of a substrate with level difference, while having small film thickness difference after embedding. A protective film is produced using this composition. A substrate has a resist pattern. A method produces a semiconductor device. A composition forms a protective film against a wet etching liquid for semiconductors, containing a solvent and a ring-opened polymer (C) obtained by reaction between a diepoxy compound (A) and a bi- or higher functional proton-generating compound (B). The ring-opened polymer (C) is preferably represented by a unit structure of formula (A-1). (In formula (A-1), Q represents a divalent organic group generated by the diepoxy compound (A) ring-opening polymerization; and T represents a divalent organic group derived from the bi- or higher functional proton-generating compound (B)).