SiGe Etching Solution Using Periodic Acid and Fluoride
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Solution Overview
Problem
Conventional etching solutions for SiGe compounds are chemically unstable, leading to fluctuating etching rates over time, which complicates the manufacturing process of semiconductor elements.
Innovation Solution
An etching solution comprising periodic acid and fluoride is used to selectively etch SiGe compounds, providing improved stability and control over the etching rate by oxidizing the SiGe compound and maintaining a stable redox potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching solutions (containing diol compounds, peracetic acid, and fluoride) are used, then etching capability for SiGe compound is achieved, but chemical stability deteriorates and etching rate fluctuates over time
Solution Approach 1:
The patent changes the chemical parameters of the etching solution by replacing conventional oxidizing agents (peracetic acid) with periodic acid as the oxidizing species and using specific diol compounds (1,3-propanediol or 1,4-butanediol) as stabilizing agents. This parameter change results in a chemically stable solution that maintains consistent etching rate over time while preserving the etching capability for SiGe compounds.
2Reliability
If etching solution chemistry is changed to improve stability, then etching rate stability improves, but etching capability for SiGe compound may be reduced
Solution Approach 1:
The patent optimizes the concentration parameters of periodic acid (0.01-5 wt%) and fluoride (0.01-5 wt%) to achieve both high etching rate and stability. By carefully controlling these parameters, the solution maintains excellent etching capability for SiGe compounds while achieving chemical stability and consistent etching rate over time.
Solution Approach 2:
The patent creates a composite etching solution system combining periodic acid as oxidizing agent, fluoride as etching agent, and specific diol compounds as stabilizers. This composite formulation synergistically achieves both high etching rate and long-term stability, resolving the contradiction between productivity and reliability.
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 solution with periodic acid and fluoride ensures a stable etching rate over time, allowing for reliable control of the manufacturing process and consistent performance even after storage, thereby stabilizing the etching process for SiGe compounds.
Implementation Method 1
the etching solution according to a first aspect includes periodic acid and fluoride... by oxidizing the SiGe compound and maintaining a stable redox potential
Implementation Method 2
the etching solution according to a first aspect includes periodic acid and fluoride... selectively etching a compound represented by general formula Si1-xGex
Data Source
AI summary
A SiGe compound etching solution for selectively etching a compound represented by general formula Si1-xGex (provided that x is 0 or more and less than 1) relative to Si, Ge and an oxide thereof, the SiGe compound etching solution including periodic acid and fluoride.