Positive Resist Polymer Molecular Weight Distribution Control
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Solution Overview
Problem
The existing α-methylstyrene-methyl α-chloroacrylate copolymer-based positive resist exhibits excessive film reduction under low irradiation, limiting its ability to form high-resolution patterns with minimal top-collapse.
Innovation Solution
A polymer with a specific molecular weight distribution, where the proportion of components less than 6,000 is no greater than 0.5%, and a weight average molecular weight of at least 55,000, is used to reduce film reduction rates under low irradiation, enhancing pattern resolution and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an α-methylstyrene-methyl α-chloroacrylate copolymer is used as a positive resist, then sensitivity is improved, but film reduction rate under low irradiation increases excessively
Solution Approach 1:
The patent applies parameter changes by strictly controlling the molecular weight distribution parameters of the copolymer. Specifically, it limits the proportion of components with molecular weight less than 6,000 to no more than 0.5% and sets the weight average molecular weight to at least 55,000. These parameter controls optimize the balance between sensitivity and film reduction rate, resolving the technical contradiction.
Solution Approach 2:
The patent uses a composite approach by combining α-methylstyrene units and methyl α-chloroacrylate units in specific proportions within the copolymer structure. This composite material design, with controlled molecular weight distribution, achieves both high sensitivity and low film reduction rate under low irradiation conditions.
2Ease of operation
If the proportion of low molecular weight components is increased, then processability is improved, but film reduction rate under low irradiation increases
Solution Approach 1:
The patent optimizes the parameter of molecular weight distribution by limiting low molecular weight components (less than 6,000) to no more than 0.5% while maintaining weight average molecular weight at least 55,000. This parameter optimization ensures adequate processability while minimizing film reduction rate under low irradiation.
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 polymer achieves a low film reduction rate and high-resolution pattern formation with reduced top-collapse, improving the sensitivity and characteristics of the positive resist.
Implementation Method 1
Polymers that display increased solubility in a developer after undergoing main chain scission through irradiation with ionizing radiation, such as an electron beam, or short-wavelength light, such as ultraviolet light
Implementation Method 2
irradiation with ionizing radiation or the like
Data Source
AI summary
Provided are a polymer that can be favorably used as a positive resist having a low film reduction rate in a state of low irradiation with ionizing radiation or the like and a positive resist composition that can favorably form a high-resolution pattern. The polymer includes an α-methylstyrene unit and a methyl α-chloroacrylate unit, and the proportion of components having a molecular weight of less than 6,000 in the polymer is no greater than 0.5%. The positive resist composition contains the aforementioned polymer and a solvent.