Dual Resist Lithography for Isolated Pattern Formation
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Solution Overview
Problem
Current double patterning processes face challenges in forming high-resolution isolated space patterns or hole patterns, particularly due to increased production steps, reagent usage, and costs, and are unsuitable for forming isolated space patterns or hole patterns effectively.
Innovation Solution
A method involving a two-step resist pattern formation process using a positive chemically amplified resist composition followed by a negative chemically amplified resist composition, where a first resist pattern is formed and then a second resist pattern is created with specific post-exposure bake treatments to enhance solubility changes in an alkali developing solution, allowing for the formation of high-resolution isolated space or hole patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional double patterning process is used to form isolated space patterns or hole patterns, then production steps and reagent usage increase, but manufacturing precision deteriorates
Solution Approach 1:
The patent divides the patterning process into two distinct steps using different resist compositions: a first positive-type chemically amplified resist for initial patterning, and a second negative-type chemically amplified resist for subsequent patterning. This segmentation allows each resist to be optimized for its specific function, enabling formation of isolated space patterns and hole patterns with high resolution while managing process complexity
Solution Approach 2:
The patent changes the chemical parameters of the resist system by switching between positive-type and negative-type chemically amplified resists with different solubility characteristics. The first resist increases solubility in alkali solution upon exposure, while the second resist decreases solubility, creating complementary effects that enable precise formation of isolated space and hole patterns
2Reliability
If a positive chemically amplified resist is used for first patterning, then solubility increases in alkali solution upon exposure, but isolated space patterns cannot be formed effectively
Solution Approach 1:
The patent applies the inversion principle by using a negative-type chemically amplified resist for the second patterning step, which does the opposite of the first resist: instead of increasing solubility upon exposure, it decreases solubility in alkali solution. This inverted approach allows the exposed portions to remain as the pattern, enabling effective formation of isolated space patterns and hole patterns that cannot be achieved with positive-type resist alone
3Reliability
If a negative chemically amplified resist is used for second patterning, then solubility decreases in alkali solution upon exposure, but high-resolution isolated space patterns are difficult to achieve
Solution Approach 1:
The patent applies local quality by having different regions of the resist film exhibit different solubility characteristics after exposure. The first positive-type resist creates regions of high solubility where exposure occurred, while the second negative-type resist creates regions of low solubility. This local differentiation in solubility quality enables precise control over pattern formation, achieving high-resolution isolated space patterns through the interaction of these complementary regions
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
This method enables the formation of high-resolution isolated space or hole patterns with improved lithography margins and reduced production costs by optimizing the solubility changes in the resist films during the patterning process.
Implementation Method 1
a chemically amplified resist composition that includes an acid generator that generates acid upon exposure
Implementation Method 2
performing a post exposure bake treatment at a bake temperature that increases the solubility of the first resist film in an alkali developing solution
Data Source
AI summary
A method of forming a resist pattern that includes: applying a positive chemically amplified resist composition to a support to form a first resist film, exposing a region on a portion of the first resist film, performing a post exposure bake treatment and then performing developing to form a first resist pattern, and applying a negative chemically amplified resist composition to the support having the first resist pattern formed thereon, thereby forming a second resist film, exposing a region of the second resist film that includes the positions in which the first resist pattern has been formed, performing a post exposure bake treatment at a bake temperature that increases the solubility of the first resist film in an alkali developing solution and decreases the solubility of the second resist film in an alkali developing solution, and then performing developing to form a resist pattern.