Photoresist Patterning With a Planar Trim Layer for Acid Uniformity
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Solution Overview
Problem
Existing photolithographic techniques face challenges in achieving uniformity and precision in patterning nanoscale features due to non-uniform acid concentration caused by non-planar overcoat layers during the trim process, leading to defects in photoresist mandrels.
Innovation Solution
A method involving the formation of a planar trim layer over a photoresist layer, followed by a bake process to diffuse acids uniformly, reducing non-uniformity in acid concentration, and subsequent developing to remove modified regions, thereby improving patterning efficiency and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a non-planar overcoat layer is used during the trim process, then the trim layer can be formed, but non-uniform acid concentration is caused leading to defects in photoresist mandrels
Solution Approach 1:
The patent applies preliminary action by forming a planar trim layer before the bake process. This planar trim layer serves as a prepared surface that ensures uniform acid concentration during the subsequent bake process, preventing defects in the photoresist mandrels before they occur.
Solution Approach 2:
The patent changes the physical state and properties of the trim layer by making it planar instead of non-planar. This parameter change in the geometry and surface uniformity of the trim layer directly leads to uniform acid concentration distribution during the bake process, eliminating the defects caused by non-uniform acid concentration.
2Manufacturing precision
If a planar trim layer is formed, then uniform acid concentration is achieved, but the process complexity increases
Solution Approach 1:
The patent applies local quality by making only the trim layer planar while leaving the rest of the photoresist structure unchanged. This localized application of planarity to the trim layer specifically addresses the acid concentration uniformity issue without requiring complex changes to the entire photoresist patterning process.
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 method enhances the precision and uniformity of photoresist patterning by minimizing defects in narrow features, ensuring consistent acid concentration and efficient removal of modified regions, thus improving the quality of semiconductor fabrication.
Implementation Method 1
diffusing the second acid from the trim layer into unmodified regions of the photoresist layer
Implementation Method 2
reacting the first acid with a material of the exposed regions to form first modified regions
Implementation Method 3
reacting the second acid with a material of the unmodified regions to form second modified regions
Data Source
AI summary
A method includes forming a photoresist layer over a substrate. The method further includes exposing the photoresist layer to a radiation to generate a first acid in exposed regions of the photoresist layer. The method further includes forming a trim layer over the photoresist layer. The trim layer includes a second acid. The method further includes performing a bake process on the substrate having the photoresist layer and the trim layer disposed thereon. Performing the bake process includes reacting the first acid with a material of the exposed regions to form first modified regions, diffusing the second acid from the trim layer into unmodified regions of the photoresist layer, and reacting the second acid with a material of the unmodified regions to form second modified regions. The method further includes and removing the trim layer, the first modified regions, and the second modified regions.