Photosensitive Resist Underlayer Film Composition for Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor device production, the use of short-wavelength exposure lights in lithography processes leads to dimensional accuracy issues due to standing waves caused by substrate reflection and unevenness, and existing bottom anti-reflective coatings that can be removed with an alkaline developer are not effective in maintaining photoresist film thickness and pattern fidelity.
Innovation Solution
A resist underlayer film forming composition containing a polymer with hydroxy or carboxy groups, a crosslinkable compound with vinyl ether groups, a photoacid generator, and a fluoroalkylcarboxylic acid or its salt, which forms a crosslinked film that absorbs short-wavelength light, prevents intermixing with the photoresist, and can be simultaneously developed with it, maintaining pattern integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thermal crosslinkable composition is used to form a bottom anti-reflective coating, then the coating becomes insoluble in alkaline developer and prevents intermixing with photoresist, but the coating cannot be removed together with the photoresist and requires separate dry etching processing
Solution Approach 1:
The patent changes the chemical composition parameters of the bottom anti-reflective coating by incorporating specific polymers with hydroxy or carboxy groups, crosslinkable compounds with vinyl ether groups, and photoacid generators. This composition modification enables the coating to be soluble in alkaline developer after exposure, allowing simultaneous removal with photoresist while maintaining stability during coating formation through crosslinking
Solution Approach 2:
The patent creates a composite material system combining polymer (A) with hydroxy or carboxy groups, crosslinkable compound (B) with vinyl ether groups, and photoacid generator (C) in specific ratios. This composite structure provides both the stability needed for coating formation and the solubility required for simultaneous removal with photoresist in alkaline developer
2Ease of manufacture
If dry etching is used to remove the bottom anti-reflective coating, then the coating can be removed, but the photoresist film thickness is reduced and pattern fidelity deteriorates
Solution Approach 1:
The patent changes the chemical solubility parameters of the bottom anti-reflective coating by selecting specific polymer and crosslinkable compound combinations that are soluble in alkaline developer. This allows the coating to be removed via wet development rather than dry etching, preserving photoresist film thickness and pattern accuracy while achieving complete coating removal
Solution Approach 2:
The patent replaces the mechanical/physical removal method (dry etching) with a chemical dissolution method (alkaline developer washing). The bottom anti-reflective coating is designed to dissolve chemically in alkaline developer after exposure, eliminating the need for dry etching and its associated damage to photoresist patterns
3Measurement precision
If the photoresist film thickness is reduced to enhance resolution, then finer patterns can be formed, but the photoresist becomes more susceptible to damage during dry etching and film thickness maintenance becomes difficult
Solution Approach 1:
The patent replaces dry etching with alkaline developer washing for bottom anti-reflective coating removal. This substitution eliminates the mechanical/physical damage that thin photoresist films would suffer during dry etching, allowing thin films to be used for high-resolution patterning while maintaining film integrity through gentle chemical dissolution
Solution Approach 2:
The patent changes the removal mechanism parameters from physical sputtering (dry etching) to chemical dissolution (alkaline developer washing). This parameter change makes the removal process gentler and more selective, enabling the use of thinner photoresist films without compromising their structural integrity during the removal process
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 a resist underlayer film that effectively absorbs short-wavelength light, prevents intermixing with the photoresist, and allows for simultaneous development, enhancing the focus depth margin and pattern fidelity in semiconductor device production.
Implementation Method 1
a photoacid generator (C); a C4-20 fluoroalkylcarboxylic acid or a salt of the fluoroalkylcarboxylic acid (D)
Implementation Method 2
a crosslinkable compound (B) having at least two vinyl ether groups
Implementation Method 3
provides a resist underlayer film that effectively absorbs short-wavelength light
Data Source
AI summary
A resist underlayer film forming composition used in a lithography process includes: a polymer (A) containing a unit structure having a hydroxy group, a unit structure having a carboxy group, or combination thereof; a crosslinkable compound (B) having at least two vinyl ether groups; a photoacid generator (C); a C4-20 fluoroalkylcarboxylic acid or a salt of the fluoroalkylcarboxylic acid (D); and a solvent (E). The polymer (A) includes a unit structure selected from unit structures of Formula (1), Formula (2), and Formula (3);