Positive Resist Composition Bridge Prevention
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Solution Overview
Problem
Conventional positive resist compositions face challenges in achieving high etching resistance and resolution, particularly when forming patterns with line widths of 50 nm or less, as they tend to form bridges between pattern lines due to insufficient mechanical strength and sensitivity issues related to the amount of basic and acid generator components.
Innovation Solution
A positive resist composition comprising a base resin with acidic functional groups protected by acid labile groups, a nitrogen-containing compound as a basic component, and an acid generator, where the base resin contains repeating units represented by specific general formulae, enabling enhanced etching resistance and resolution by adjusting solubility and reactivity, and incorporating acenaphthylene derivatives to increase rigidity and prevent bridge formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of basic component is increased to enhance contrast against acid, then etching resistance is improved, but sensitivity of the resist deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the basic component by using a specific nitrogen-containing compound with a molecular weight of 100 to 500 and a basicity value of 0.5 to 2.0. This parameter optimization allows achieving high etching resistance while maintaining sensitivity, resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite resist composition system combining the base resin with the specifically designed nitrogen-containing compound and acid generator. This composite approach allows synergistic effects where the basic component provides etching resistance while the acid generator maintains sensitivity, preventing the trade-off between these properties.
2Reliability
If the amount of acid generator is increased to compensate for sensitivity deterioration, then sensitivity is improved, but attenuation of exposure light within the film occurs
Solution Approach 1:
The patent optimizes the acid generator to have a maximum absorption wavelength of 150 to 220 nm and controls its addition amount to 1 to 20 parts by mass relative to 100 parts by mass of base resin. This parameter control ensures sufficient sensitivity while minimizing light attenuation, resolving the contradiction between sensitivity and energy loss.
3Ease of manufacture
If conventional polymer systems are used for fine processing, then ease of manufacture is maintained, but bridges are caused between pattern lines making it difficult to form fine patterns
Solution Approach 1:
The patent modifies the polymer structure by incorporating acenaphthylene units (70-90 mol%) with specific rigidity parameters and glass transition temperatures. This structural parameter change enhances mechanical strength and prevents bridge formation during development, achieving fine pattern formation while maintaining ease of manufacture through conventional processing methods.
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 improved etching resistance and resolution, preventing bridge formation and enhancing pattern profile quality, even at substrate-side boundary faces, suitable for photolithography using KrF laser, extreme ultraviolet rays, or electron beams.
Implementation Method 1
an acid generator to be decomposed by exposure light to produce an acid
Implementation Method 2
a basic compound for restricting diffusion of the acid produced by the typical exposure
Data Source
AI summary
There is disclosed a positive resist composition comprising at least: (A) a base resin, which has acidic functional groups protected by acid labile groups, respectively, and is insoluble or hardly soluble in alkali, and which is turned to be soluble in alkali upon elimination of the acid labile groups; (B) an acid generator; and (C) a nitrogen-containing compound as a basic component; wherein the base resin is: a polymer containing repeating units each represented by the following general formula (1); or a polymer containing repeating units each represented by the general formula (1), and containing at least one or more kinds of repeating units each represented by the following general formula (2) and repeating units each represented by the following general formula (3); and wherein the base resin contains the repeating units represented by the general formulae (1), (2), and (3), respectively, at a sum ratio of 70 mole % or more relative to a total amount of all repeating units constituting the base resin. There can be provided: a positive resist composition having an enhanced etching resistance and an excellent resolution and being capable of providing an excellent pattern profile even at a substrate-side boundary face of resist, in photolithography for fine processing, and particularly in lithography adopting, as an exposure source, KrF laser, extreme ultraviolet rays, electron beam, X-rays, or the like; and a pattern forming process utilizing the positive resist composition.