Noble Metal Catalyst Etching for Semiconductor Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching methods for semiconductor substrates often result in the formation of porous residual portions and uneven etching patterns, particularly when using metal-assisted chemical etching (MacEtch), which can hinder the production of high-quality semiconductor chips.
Innovation Solution
The method involves forming an uneven structure with a projection on the semiconductor substrate, depositing a noble metal catalyst layer on the projection, and using an etchant to etch the substrate, preventing the catalyst from diffusing under the mask layer and thus avoiding the formation of porous residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metal-assisted chemical etching (MacEtch) is used to etch semiconductor substrates, then etching efficiency is improved, but porous residual portions are formed and etching uniformity deteriorates
Solution Approach 1:
The patent applies local quality by forming projections with specific geometric features (rounded corners, specific aspect ratios) in strategic locations on the substrate. These localized structural modifications create controlled etching behavior at specific regions while maintaining overall etching uniformity, resolving the contradiction between efficient etching and uniformity by making the substrate surface non-uniform in a controlled manner.
2Productivity
If catalyst layer is deposited on flat substrate surface, then catalytic etching is achieved, but catalyst diffuses under mask layer causing unwanted etching
Solution Approach 1:
The patent applies preliminary action by pre-forming projections on the substrate surface before depositing the catalyst layer. These projections serve as predetermined sites that confine the catalyst to specific locations, preventing lateral diffusion under the mask layer. The projections are formed in advance with geometric features that actively prevent catalyst migration, ensuring precise etching pattern control while maintaining catalytic etching efficiency.
3Ease of manufacture
If conventional etching methods are used, then process simplicity is maintained, but porous residues are generated reducing chip quality
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the substrate surface - specifically creating projections with controlled dimensions, aspect ratios, and corner radii. These parameter modifications to the substrate topology enable the etching process to proceed without generating porous residues, while adding only a single projection formation step to the conventional process flow.
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
This approach prevents the generation of porous residual portions, allowing for controlled and directional etching that enhances the quality and yield of semiconductor chips by ensuring uniform etching without cross-directional etching issues.
Implementation Method 1
forming a catalyst layer including a noble metal on the projection; and supplying an etchant to the catalyst layer to etch the semiconductor substrate with an assist from the noble metal as a catalyst
Data Source
AI summary
An etching method according to an embodiment includes forming an uneven structure including a projection on a surface of a semiconductor substrate; forming a catalyst layer including a noble metal on the surface selectively at a top surface of the projection; and supplying an etchant to the catalyst layer to cause an etching of the semiconductor substrate with an assist from the noble metal as a catalyst.