Chemically Amplified Positive Resist for Stable Fine Patterning
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Solution Overview
Problem
Existing chemically amplified resist compositions face challenges in achieving high resolution, small line edge roughness (LER), pattern profile stability, and etching resistance, particularly in photomask processing, due to acid diffusion and sensitivity issues, which affect throughput and pattern uniformity.
Innovation Solution
A chemically amplified positive resist composition using a polymer containing a repeat unit derived from an onium salt with an aromatic sulfonate anion and a triarylsulfonium cation, along with specific repeat units, to enhance solvent solubility and lithographic performance, including resistance to pattern collapse and etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the volume of acid generated from an acid generator is increased to prevent acid diffusion, then resolution is improved, but line edge roughness increases and pattern profile stability deteriorates
Solution Approach 1:
The patent introduces a base polymer containing multiple different repeat units (repeat units (1) to (4)) with distinct functions: repeat unit (1) provides acid generation, repeat unit (2) controls acid diffusion, repeat unit (3) enhances solubility, and repeat unit (4) improves etching resistance. This segmentation of functions within the polymer structure allows optimization of each parameter independently, resolving the contradiction between resolution and pattern profile stability.
Solution Approach 2:
The patent creates a composite polymer structure by copolymerizing multiple monomers with different functionalities. The base polymer combines acid-generating groups, acid diffusion control groups, solubility-enhancing groups, and etching-resistant groups into a single integrated material, achieving synergistic effects that resolve the technical contradiction between high resolution and stable pattern profiles.
2Manufacturing precision
If a repeat unit that generates acid by exposure is introduced into the base polymer to control acid diffusion, then line edge roughness is reduced, but solubility in organic solvent deteriorates
Solution Approach 1:
The patent assigns specific local functions to different repeat units within the polymer. Repeat unit (3) is specifically designed with solubility-enhancing groups (such as alkoxy or hydroxyl groups) that are localized to provide good organic solvent solubility, while repeat units (1) and (2) handle acid generation and diffusion control. This local differentiation of properties resolves the contradiction between reducing line edge roughness and maintaining solubility.
3Manufacturing precision
If high-energy radiation exposure is used for ultrafine processing, then pattern resolution is improved, but throughput decreases due to sequential writing time
Solution Approach 1:
The patent changes the sensitivity parameter of the resist composition by incorporating the base polymer with acid-generating repeat units and acid diffusion control units. This formulation achieves high sensitivity to high-energy radiation, allowing faster exposure times and improved throughput while maintaining ultrafine pattern resolution. The polymer's molecular weight and composition are optimized to enhance radiation response.
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 achieves high resolution, reduced LER, stable pattern profiles, and excellent etching resistance, suitable for small-size pattern formation in photolithography using high-energy radiation.
Implementation Method 1
a base polymer (A) containing a polymer adapted to increase its solubility in an alkaline aqueous solution under the action of acid
Implementation Method 2
a sulfonium cation having the formula (A1-2)
Data Source
AI summary
A chemically amplified positive resist composition containing a base polymer (A) which is a polymer whose solubility in an aqueous alkaline solution is increased by the action of an acid, contains a repeat unit containing an aromatic sulfonate anion having the formula (A1-1) and a sulfonium cation having the formula (A1-2) and a repeat unit having the formula (A2), and contains a polymer whose solubility in an aqueous alkaline solution is increased by the action of an acid.