Radiation-Sensitive Resist Composition for Acid Diffusion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radiation-sensitive compositions struggle to form fine resist patterns with uniform dimensions and suppress development failures, particularly when forming patterns with line widths of 40 nm or less, due to inadequate control of acid diffusion and insufficient developer contact.
Innovation Solution
A radiation-sensitive composition containing a polymer with a specific structural unit and a radiation-sensitive acid-generator, comprising an onium cation with fluoroalkyl or fluoro groups and an organic anion with an iodine atom, is used to form a resist film, which is exposed to radiation and developed to achieve high sensitivity and critical dimension uniformity (CDU) performance while minimizing development failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a radiation-sensitive composition is designed to achieve high sensitivity for fine pattern formation, then the required exposure dose can be reduced, but acid diffusion control becomes insufficient leading to poor critical dimension uniformity
Solution Approach 1:
The patent introduces a base polymer with specific local chemical groups (carboxylic acid groups with pKa 3-7) that create localized acid-base interactions. These local interactions control acid diffusion in the radiation-exposed regions while maintaining high sensitivity, resolving the contradiction between low exposure dose and CDU performance.
Solution Approach 2:
The patent uses a composite resist system combining a base polymer (with controlled acid diffusion properties) and a radiation-sensitive polymer (providing sensitivity). This composite approach allows simultaneous achievement of high sensitivity and acid diffusion control for fine pattern formation with excellent CDU.
2Length of moving object
If the resist pattern size is reduced to achieve further process shrinkage (e.g., 40 nm or less line width), then finer patterns can be formed, but development failures increase due to insufficient developer contact
Solution Approach 1:
The patent modifies the chemical parameters of the resist system by introducing base polymers with specific pKa ranges (3-7) for carboxylic acid groups. This parameter change enhances developer interaction and prevents development failures in fine patterns while maintaining the ability to form ultra-fine structures.
Solution Approach 2:
The base polymer acts as an intermediary between the radiation-sensitive polymer and the developer. It facilitates proper developer contact and dissolution control in fine patterns, preventing development failures while enabling continued pattern size reduction.
3Quantity of substance
If acid diffusion is increased to improve sensitivity, then fewer exposure conditions are needed, but uniformity in resist pattern dimension deteriorates
Solution Approach 1:
The patent creates local acid-base interaction zones using base polymers with specific pKa values. These localized interactions control acid diffusion pathways, allowing efficient acid generation where needed while preventing excessive diffusion that would compromise pattern dimension uniformity.
Solution Approach 2:
By adjusting the pKa parameters of the base polymer's carboxylic acid groups (specifically in the 3-7 range), the patent optimizes the balance between acid generation efficiency and acid diffusion control, achieving both high sensitivity and CDU performance.
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 enables the formation of resist patterns with excellent CDU performance and reduced development failures, even at small doses, by controlling acid diffusion and ensuring uniformity in pattern dimensions.
Implementation Method 1
a process target formed of a radiation-sensitive composition is irradiated with a far-UV ray (e.g., ArF excimer laser light), an extreme UV (EUV) ray, an electron beam, or the like, to thereby generate acid in a radiation-exposed part
Data Source
AI summary
A radiation-sensitive composition contains: (A) a polymer including a structural unit (U) represented by the following formula (1); and (B) a radiation-sensitive acid-generator formed of an onium cation having at least one group Rf1 selected from the group consisting of a fluoroalkyl group and a fluoro group (excepting a fluoro group in the fluoroalkyl group) and an organic anion having an iodine atom. In formula (1), R1 represents a hydrogen atom, a methyl group, or the like. X1 represents a single bond, an ether bond, an ester bond, or the like. Ar1 represents a cyclic group bound to X1 via an aromatic ring. A hydroxy group or group —ORY is bound to an atom adjacent to the atom bound to X1, among the atoms forming the aromatic group in Ar1. RY represents an acid-releasable group.