Resist Composition for 248 nm Lithography Film Thickness
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Solution Overview
Problem
As the film thickness of resist films increases, maintaining sensitivity during exposure becomes more difficult, leading to reduced resolution and desired resist pattern shape, along with potential shape deterioration due to decreased light transmittance.
Innovation Solution
A resist composition comprising a resin with a molar absorption coefficient of 2,000 mol−1·L·cm−1 or less at 248 nm, an acid generator, and a crosslinking agent, such as melamine-based or epoxy-based crosslinking agents, which improves transmittance and solubility characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the film thickness of the resist film is increased, then the capacity of memory by stacking cells is improved, but the sensitivity during exposure deteriorates and resolution is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the resist material by incorporating specific base materials (polyhydroxystyrene derivatives, carboxylic acid polymers) and acid generators that work synergistically to maintain sensitivity in thick films. The molar ratio and concentration of each component are precisely controlled to optimize both thickness and resolution
Solution Approach 2:
The patent uses a composite resist system combining multiple polymer components (polyhydroxystyrene with poly carboxylic acid), crosslinking agents, and acid generators. This composite structure allows the thick film to maintain both mechanical integrity and chemical sensitivity to exposure light, resolving the contradiction between thickness and resolution
2Volume of moving object
If the film thickness of the resist film is increased, then the memory capacity by stacking cells is improved, but the light transmittance decreases causing shape deterioration
Solution Approach 1:
The patent optimizes the optical parameters of the resist by selecting base materials with appropriate absorption coefficients and incorporating transparent crosslinking agents. The film composition is engineered to balance thickness with light transmission, ensuring sufficient exposure reaches the substrate interface while maintaining pattern definition
Solution Approach 2:
The acid generator acts as an intermediary that amplifies the exposure effect. Upon absorbing light, it generates acid that catalyzes crosslinking reactions, allowing the resist to respond effectively to exposure even when light transmittance is reduced by increased film thickness
3Volume of moving object
If the film thickness of the resist film is increased, then the memory capacity by stacking cells is improved, but the solubility at substrate interface deteriorates
Solution Approach 1:
The patent modifies the solubility parameters of the resist system by incorporating poly carboxylic acid components that provide controlled solubility in the developing solution. The crosslinking density and polymer chain structure are optimized to ensure the substrate interface region maintains appropriate solubility for complete development while supporting increased film thickness
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 resist composition enables the formation of resist patterns with improved resolution, depth of focus (DOF), and pattern shape, even at increased film thicknesses.
Implementation Method 1
an acid generator component that generates acid upon exposure
Implementation Method 2
the resin (A) is an alkali-soluble resin having a molar absorption coefficient of 2,000 mol−1·L·cm−1 or less at a wavelength of 248 nm
Data Source
AI summary
A resist composition containing a resin, an acid generator, and a crosslinking agent, in which the resin is an alkali-soluble resin having a molar absorption coefficient of 2,000 mol−1·L·cm−1 or less at a wavelength of 248 nm, and the crosslinking agent is at least one of a melamine-based crosslinking agent, a urea-based crosslinking agent, an alkylene urea-based crosslinking agent, a glycoluril-based crosslinking agent, and an epoxy-based crosslinking agent.