Semiconductor Sidewall Spacer Layer for Over-Etching Prevention
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Solution Overview
Problem
Conventional semiconductor patterning processes often result in poor quality target patterns due to over-etching of the base substrate, leading to performance degradation and yield issues in semiconductor structures.
Innovation Solution
A method involving the formation of a sidewall spacer layer with distinct thickness portions on a semiconductor structure, where the first portion serves as a hard mask layer and the second portion is selectively removed using a plasma treatment and wet etching process to prevent over-etching and ensure a planar surface, thereby improving pattern quality and reducing micro-loading effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching process is used to form target pattern, then etching can be completed, but over-etching occurs causing poor pattern quality and height differences
Solution Approach 1:
The sidewall spacer layer is divided into two portions with different thicknesses: a first portion (thinner) on the sidewalls that serves as hard mask, and a second portion (thicker) on the base substrate that prevents over-etching. This segmentation allows the etching process to stop at the correct depth while maintaining pattern quality.
Solution Approach 2:
The sidewall spacer layer is formed in advance before the etching process, with the thicker second portion pre-positioned on the base substrate. This preliminary action ensures that the etching process has a built-in depth limit, preventing over-etching and micro-loading effects before they can occur.
2Adaptability or versatility
If existing DP process is used for substrate etching, then double-patterning can be achieved, but target pattern quality remains undesirable
Solution Approach 1:
The sidewall spacer layer exhibits local quality variations with different thicknesses at different locations. The first portion on sidewalls provides mask functionality, while the second portion on the base substrate provides etching depth control. This local differentiation enables both double-patterning and high pattern quality.
Solution Approach 2:
The sidewall spacer layer acts as an intermediary structure between the hard mask layer and the base substrate. It transfers the patterning function while simultaneously controlling the etching depth, thereby enabling double-patterning with improved target pattern quality.
3Ease of manufacture
If uniform thickness sidewall spacer layer is used, then fabrication is simpler, but over-etching cannot be prevented and micro-loading effects occur
Solution Approach 1:
The sidewall spacer layer is segmented into two functional portions with different thicknesses. This segmentation, while adding a step in fabrication, provides reliable etching control by preventing over-etching and eliminating micro-loading effects, thereby improving overall process reliability.
Solution Approach 2:
The thickness parameter of the sidewall spacer layer is changed spatially to create two distinct portions. This parameter variation enables precise control of the etching process, preventing over-etching and micro-loading effects while maintaining acceptable fabrication complexity.
Data Source
AI summary
A semiconductor structure a base substrate and a sidewall spacer layer formed on the base substrate. The sidewall spacer layer includes a plurality of first sidewall spacer layers and a plurality of second sidewall spacer layers spaced apart from each other. At least one sidewall of a second sidewall spacer layer of the plurality of second sidewall spacer layers is formed on a first sidewall spacer layer of the plurality of first sidewall spacer layers. The plurality of first sidewall spacer layers has a thickness greater than the plurality of second sidewall spacer layers, based on a surface of the base substrate. The plurality of first sidewall spacer layers has a material structure different than the plurality of second sidewall spacer layers.