Semiconductor Structure Mask Removal for Flat Region-Specific Etching
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Solution Overview
Problem
The existing semiconductor structure formation process results in unevenness due to damage to the insulating layer in one region and residue issues with the mask layer in another, leading to reduced performance and flatness.
Innovation Solution
A method is introduced where a first protection layer is formed on the upper surface and sidewall of the mask layer in the first region, allowing for separate removal of the mask layers in different regions, thereby preventing damage to the insulating layer and ensuring complete removal without residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mask layer is removed in a single step after trench formation, then the process is simple and fast, but mask layer residues remain in the second region and the insulating layer is damaged in the first region
Solution Approach 1:
The mask layer removal process is divided into two separate steps: first removing the mask layer in the second region, then removing the mask layer in the first region. This segmentation allows each region to be processed according to its specific requirements, eliminating residues while preventing insulating layer damage.
Solution Approach 2:
Before removing the mask layer in the first region, a protection layer is formed on the insulating layer. This preliminary protective action prevents the insulating layer from being damaged during the subsequent mask layer removal process, ensuring the flatness of the semiconductor structure.
2Ease of manufacture
If the mask layer thickness varies between regions, then the patterned etching can be achieved, but uneven mask layer thickness causes incomplete removal and residues
Solution Approach 1:
The mask layer removal is segmented into region-specific steps. The second region (with thicker mask layer) is processed first to remove the majority of the mask material, followed by the first region (with thinner mask layer). This segmented approach ensures complete removal without residues in either region.
Solution Approach 2:
Different removal strategies are applied to different regions based on their local characteristics. The second region receives a removal process optimized for thicker mask layers, while the first region receives a removal process optimized for thinner mask layers, with additional protection to prevent insulating layer damage.
3Ease of manufacture
If the mask layer in the first region is etched during trench formation, then the trench can be formed, but the mask layer thickness becomes non-uniform across regions
Solution Approach 1:
A protection layer is preliminarily formed on the insulating layer in the first region before the final mask layer removal step. This preliminary protection ensures that when the mask layer is removed, the insulating layer is not damaged, maintaining the structural integrity and uniformity of the semiconductor device.
Solution Approach 2:
The protection layer acts as an intermediary between the mask layer removal process and the insulating layer. It absorbs the harmful effects of the removal process, allowing complete mask layer removal without damaging the underlying insulating layer, thus maintaining composition stability.
Data Source
AI summary
An embodiment of the application provides a method for forming a semiconductor structure. The semiconductor structure includes a first region and a second region. The method includes the following steps: providing a base, an insulating layer, and a mask layer that are stacked in sequence, where the first region has at least one trench penetrating the mask layer and the insulating layer, and the mask layer has an upper surface in the second region higher than that in the first region; forming a first protection layer, where an upper surface and a sidewall of the mask layer in the first region are covered with the first protection layer; after the first protection layer is formed, removing the mask layer in the second region; subsequent to removal of the mask layer in the second region, removing the first protection layer; and removing the mask layer in the first region.