Photoresist Composition Segmentation for Lithographic Uniformity
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Solution Overview
Problem
Current photoresist compositions face challenges in achieving uniform critical dimensions, increased contact hole exposure latitude, improved line-space exposure latitude, and reduced line width roughness due to photoacid generator non-uniformity and acid diffusion issues, which limit photolithographic performance.
Innovation Solution
A photoresist composition comprising a first polymer with 50 to 100 mole percent photoacid-generating repeat units, each containing an anion, a photoacid-generating cation, and base-solubility-enhancing functionality, along with a second polymer that exhibits a change in solubility in an alkali developer under acid action, enhancing photolithographic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If increased concentration of PAG in the matrix is used, then lithographic performance is enhanced, but PAG non-uniformity and acid diffusion worsen
Solution Approach 1:
The photoacid generator is segmented into two distinct components: a polymer-bound photoacid generator (PBP) providing uniform distribution and a free photoacid generator providing high acid concentration. This segmentation allows each component to fulfill different functional requirements - the PBP ensures PAG uniformity and controlled acid diffusion, while the free PAG enhances lithographic performance through increased acid concentration.
Solution Approach 2:
The photoresist composition uses a composite system combining polymer-bound photoacid generator and free photoacid generator in specific weight ratios (0.1-10:0.9-0.1). This composite approach leverages the advantages of both components: the PBP's uniform distribution and controlled diffusion characteristics, and the free PAG's high concentration effect, achieving superior lithographic performance without the drawbacks of using either component alone.
2Manufacturing precision
If polymer-bound-PAG system is implemented, then PAG uniformity increases, but acid diffusion control is limited
Solution Approach 1:
The system segments the photoacid generator functionality between polymer-bound and free forms, where the PBP component provides uniform distribution and the free PAG component provides sufficient acid concentration for high productivity lithographic processes.
Solution Approach 2:
The composite photoresist system combines PBP and free PAG in optimized ratios, where the PBP ensures uniform PAG distribution while the free PAG maintains adequate acid diffusion for productive lithographic performance.
3Productivity
If feature sizes are reduced, then device density increases, but photoresist resolution deteriorates
Solution Approach 1:
The composite photoresist system with PBP and free PAG in specific ratios provides both the uniformity needed for high resolution and the acid concentration needed for productive lithographic processes, enabling successful patterning at reduced feature sizes.
Solution Approach 2:
The invention changes the PAG distribution parameters by using a combination of polymer-bound and free PAG forms, optimizing both uniformity and concentration to achieve the required photoresist resolution for reduced feature sizes.
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 decreased critical dimension uniformity, increased exposure latitude, and improved line width roughness, manifesting as improved photolithographic performance with increased contrast slope and reduced dose to clear energy.
Implementation Method 1
a photoacid-generating cation, and base-solubility-enhancing functionality; wherein either the anion or the photoacid-generating cation is polymer-bound
Implementation Method 2
a second polymer that exhibits a change in solubility in an alkali developer under the action of acid
Data Source
AI summary
A photoresist composition includes a first polymer in which at least half of the repeat units are photoacid-generating repeat units, and a second polymer that exhibits a change in solubility in an alkali developer under the action of acid. In the first polymer, each of the photoacid-generating repeat units comprises photoacid-generating functionality and base-solubility-enhancing functionality.