Etching Agent Composition for Smooth Semiconductor Recess Bottoms
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Solution Overview
Problem
Existing metal-assisted chemical etching methods fail to adequately enhance the smoothness of the bottom surface of recesses formed in semiconductor substrates.
Innovation Solution
An etching agent comprising hydrogen fluoride, ammonium fluoride, and an oxidizing agent, with a molar concentration ratio of 0.5≤n/m≤5.0, is used to perform metal-assisted chemical etching on semiconductor substrates with noble metal regions, forming recesses with a smooth bottom surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional metal-assisted chemical etching is used, then etching can be performed on semiconductor substrates, but the bottom surface of the recess cannot be sufficiently smoothed
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration ratio of hydrogen fluoride to ammonium fluoride in the etching agent, specifically setting the ratio within 0.5≤n/m≤5.0. This chemical parameter adjustment enables the etching process to simultaneously achieve high etching rates and smooth bottom surfaces, resolving the contradiction between productivity and manufacturing precision
Solution Approach 2:
The patent uses a composite etching agent system combining hydrogen fluoride, ammonium fluoride, and oxidizing agents in specific proportions. This composite chemical formulation creates a synergistic effect that maintains high etching efficiency while producing smooth recess bottom surfaces, addressing both productivity and precision requirements
2Productivity
If conventional etching agents are used, then etching process can be completed, but environmental impact is increased
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching agent by incorporating ammonium fluoride and controlling the hydrogen fluoride to ammonium fluoride ratio. This parameter optimization reduces the environmental impact of the etching process while maintaining high etching rates, thus resolving the contradiction between productivity and environmental harm reduction
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 etching method achieves recesses with a smooth bottom surface, enhancing etching accuracy and reducing environmental impact while maintaining a high etching rate.
Implementation Method 1
an etching method in which an etching agent containing hydrogen fluoride acid, an oxidizing agent, and a buffering agent is supplied to a semiconductor substrate
Implementation Method 2
etching of the semiconductor substrate is caused at a position of the catalyst layer
Data Source
AI summary
According to the disclosure, provided is an etching agent for etching a semiconductor substrate having a surface partially covered with a noble metal, the etching agent including: an oxidizing agent; hydrogen fluoride; and ammonium fluoride. 0.5≤n/m≤5.0 is satisfied, where m is a molar concentration [mol/L] of the hydrogen fluoride, and n is a molar concentration [mol/L] of the ammonium fluoride.