Positive Resist Hole Pattern Formation via Alkaline Reversal
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Solution Overview
Problem
Current lithography techniques face challenges in forming ultra-dense hole patterns due to low resolution and reduced throughput, particularly with negative resist materials, and the complexity of double patterning processes, which require multiple exposures and etchings, leading to misregistration and deformation issues.
Innovation Solution
A process involving a chemically amplified positive resist composition exposed through a phase shift mask with a lattice-like array, followed by partial crosslinking and alkaline development to form a dense dot pattern, which is then reversed into a hole pattern using a reversal film-forming composition, allowing for single exposure and high-resolution hole pattern formation with improved alignment accuracy and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative resist materials are used for hole pattern formation, then the pattern can be formed, but the resolution and throughput are reduced
Solution Approach 1:
The patent inverts the conventional approach by using positive resist materials instead of negative resist materials for hole pattern formation. The positive resist forms a dot pattern that is then reversed into a hole pattern through alkaline wet etching, achieving both high resolution and high throughput without the limitations of negative resist materials
2Manufacturing precision
If double patterning processes are used for ultra-dense hole patterns, then the pattern density can be increased, but the process complexity and misregistration issues increase
Solution Approach 1:
The patent segments the hole pattern formation into two distinct stages: first forming a dot pattern using positive resist with a lattice-like mask, then reversing it to a hole pattern through alkaline wet etching. This segmentation allows each stage to be optimized independently, achieving ultra-dense patterns without the misregistration issues of conventional double patterning
Solution Approach 2:
The patent introduces a dot pattern as an intermediary form between the initial resist pattern and the final hole pattern. This intermediary dot pattern serves as a precise template that can be cleanly reversed into holes through wet etching, avoiding the direct complexity of double patterning while achieving the same density
3Manufacturing precision
If double patterning processes are used for ultra-dense hole patterns, then the pattern density can be increased, but deformation issues occur
Solution Approach 1:
The patent replaces the mechanical/physical processes of conventional double patterning (multiple exposures, dry etching, re-coating) with a chemical process - alkaline wet etching. This chemical approach provides more uniform material removal and better pattern fidelity, reducing deformation while achieving high density
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
This method achieves high-resolution, ultra-dense hole patterns with reduced proximity bias and increased throughput by using positive resist materials and alkaline wet etching, overcoming the limitations of negative resist materials and double patterning processes.
Implementation Method 1
a photoacid generator capable of generating an acid upon exposure to high-energy radiation
Implementation Method 2
a thermal acid generator capable of generating an acid upon heating
Implementation Method 3
the acid generated by the acid generator upon exposure may act on acid labile groups in the resin for thereby effecting elimination reaction of acid labile groups in the resin
Implementation Method 4
to induce crosslinks in the resin to such an extent that the resin may not lose a solubility in an alkaline wet etchant, for thereby endowing the positive pattern with resistance to an organic solvent
Data Source
AI summary
A pattern is formed by coating a chemically amplified positive resist composition comprising a resin comprising acid labile group-containing recurring units and a photoacid generator onto a substrate, drying to form a resist film, exposing the resist film to high-energy radiation through a phase shift mask having a lattice-like array of shifters, PEB, developing to form a positive pattern, illuminating or heating the positive pattern to eliminate acid labile groups for increasing alkaline solubility and to induce crosslinking for imparting solvent resistance, coating a reversal film, and dissolving away the positive pattern in an alkaline wet etchant to form a pattern by way of positive/negative reversal.