Photoresist Corner Sharpening for Precise Semiconductor Patterning
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Solution Overview
Problem
Pattern corner rounding during photolithography and etching processes in semiconductor manufacturing leads to issues with process window control and critical dimension variation, as right angles in target patterns become rounded, affecting the precision of semiconductor devices.
Innovation Solution
A directional treatment using directional ion bombardment with suitable ion species, energy, and angle is applied to the photoresist pattern after lithography, hardening the photoresist and sharpening its edges to reduce corner rounding without degrading the lithography window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photolithography and etching processes are used to manufacture semiconductor devices, then production efficiency increases and costs decrease, but pattern corner rounding occurs leading to critical dimension variation and reduced manufacturing precision
Solution Approach 1:
The patent applies preliminary action by performing a directional treatment process on the photoresist pattern before the etching step. This treatment hardens the photoresist and sharpens its edges in advance, preventing corner rounding during subsequent etching. The photoresist is treated with a beam (such as electron beam or ion beam) to modify its physical properties before it is used as the etch mask, thereby proactively solving the precision problem while maintaining high productivity
Solution Approach 2:
The patent employs parameter changes by altering the physical and chemical parameters of the photoresist material through directional treatment. The treatment process changes the photoresist's hardness, edge sharpness, and structural properties at the nanoscale level. By modifying these parameters of the photoresist before etching, the process achieves both high production efficiency and improved manufacturing precision without requiring slower traditional methods
2Manufacturing precision
If the lithography window is optimized for pattern formation, then pattern quality improves, but corner rounding still occurs during etching affecting critical dimension control
Solution Approach 1:
The directional treatment is applied as a preliminary action between lithography and etching. It prepares the photoresist pattern by hardening and sharpening edges before the etching process begins. This preliminary modification ensures that even when using optimized lithography windows, the photoresist maintains its structural integrity and sharp corners during etching, thereby improving critical dimension control while preserving pattern quality
Solution Approach 2:
The treatment process induces parameter changes in the photoresist's physical properties, specifically increasing its hardness and edge definition. These parameter changes make the photoresist more resistant to corner rounding during etching, allowing the process to simultaneously achieve high pattern quality from optimized lithography and reliable critical dimension control during etching
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 effectively reduces pattern corner rounding in both the photoresist and underlying layers, improving etch selectivity and maintaining the lithography window integrity, resulting in sharper corners and enhanced manufacturing precision.
Implementation Method 1
a directional treatment is performed to harden a portion of the photoresist layer adjacent to the opening after the lithography process
Data Source
AI summary
A method includes coating a photoresist film over a target layer; performing a lithography process to pattern the photoresist film into a photoresist layer, wherein the photoresist layer has an opening, and the opening of the photoresist layer at least has a first sidewall, a second sidewall non-parallel with the first sidewall, and a first corner connecting the first and second sidewalls; performing a first directional ion bombardment process to the first corner of the photoresist layer along a first direction, wherein the first direction is non-perpendicular to both the first and second sidewalls of the photoresist when viewed from top; and after the first directional ion bombardment process is complete, patterning the target layer using the photoresist layer as a patterning mask.