Imprint Patterning with Hard Mask Residual Removal
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Solution Overview
Problem
In semiconductor patterning processes, the imprinting method often leaves residual material between patterns, which are difficult to remove without also affecting the pattern accuracy, leading to non-uniform critical dimensions and compromised electrical properties of semiconductor devices.
Innovation Solution
A patterning process that involves forming a hardmask layer between adjacent pattern portions, using it as an etching mask to remove the pattern portions and residual material, and then removing the hardmask layer to ensure precise pattern formation and eliminate the need for additional etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an etching process is performed to remove residual material after imprinting, then the residual material between patterns is removed, but a part of the imprinted pattern is also removed, resulting in reduced pattern accuracy
Solution Approach 1:
The patent divides the etching process into two distinct stages: first, a soft mask layer is used to remove residual material with low etching selectivity to preserve the pattern; second, a hard mask layer is applied to perform precise etching of the substrate. This segmentation allows each etching step to have optimized selectivity for its specific purpose, preventing pattern damage while effectively removing residuals.
Solution Approach 2:
The patent introduces a soft mask layer as an intermediary between the imprint stamp and the substrate etching process. This soft mask layer serves as a protective mediator that allows residual material removal while protecting the imprinted pattern from damage. The soft mask can be selectively removed later, having fulfilled its protective and enabling function during the etching process.
2Quantity of substance
If additional etching processes are performed to remove residual material, then the residual material is eliminated, but the process complexity increases
Solution Approach 1:
The patent combines multiple functions into the hard mask layer: it serves as both the etching mask for precise pattern transfer and as the layer that protects the pattern during residual material removal. By merging these functions into a single integrated approach with sequential mask application, the process achieves comprehensive residual removal and precise patterning without requiring multiple separate etching steps with different masks.
3Productivity
If the imprinting method is used to form patterns, then the pattern transfer efficiency is improved, but residual material remains between patterns affecting critical dimension uniformity
Solution Approach 1:
The patent applies the soft mask layer immediately after imprinting, before any etching process begins. This preliminary action of depositing the soft mask ensures that the pattern is protected from the outset during subsequent residual material removal. The soft mask is applied in advance to prevent pattern damage, allowing aggressive residual removal without compromising critical dimension uniformity.
Solution Approach 2:
The patent changes the etching selectivity parameter by using different mask layers with different etching resistance properties. The soft mask layer has low etching selectivity allowing easy removal of residuals, while the hard mask layer has high etching selectivity for precise pattern transfer. By changing the mask material parameter, the process optimizes both residual removal effectiveness and pattern precision for each etching stage.
Data Source
AI summary
A patterning process is provided. The patterning process comprises the following steps. A material layer is formed on a substrate. An imprinting process is performed on the material layer using an imprint stamp to form a patterned material layer having a plurality of pattern portions. A hard mask layer is formed between adjacent pattern portions. An etching process is performed using the hard mask layer as an etching mask to remove the pattern portions and a part of the substrate. The hard mask layer is removed.