Tungsten Etching Rate via Tungsten-Ion Catalysis
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Solution Overview
Problem
Current chemical solutions for etching tungsten on semiconductor substrates are inefficient, leading to contamination and unstable processes due to residual tungsten at the bevel portion, necessitating the development of a faster etching method to improve semiconductor device productivity.
Innovation Solution
A chemical solution with hydrogen peroxide as the main component, containing 12 ppm or more and 100,000 ppm or less of tungsten, is used in an etching apparatus that adjusts tungsten concentration and pH to enhance the etching rate, utilizing a concentration adjustment unit and controller to optimize the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional chemical solution is used to etch tungsten, then the etching process can be performed, but the etching rate is slow leading to residual tungsten contamination
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by adding tungsten ions (1-100 ppm) to the hydrogen peroxide-based solution. This parameter modification creates a self-accelerating etching mechanism where dissolved tungsten acts as a catalyst, significantly increasing the etching rate while maintaining complete removal capability.
Solution Approach 2:
The patent introduces tungsten ions as an intermediary substance that mediates the etching reaction. These ions act as a catalyst that accelerates the dissolution of tungsten from the substrate without being consumed in the process, enabling faster etching while maintaining process stability.
2Productivity
If the etching rate is increased to improve productivity, then residual tungsten is removed more effectively, but the process complexity increases due to concentration control requirements
Solution Approach 1:
The etching solution has the self-service capability of automatically maintaining its etching effectiveness. As tungsten dissolves during the etching process, the released tungsten ions automatically replenish the catalyst concentration in the solution, eliminating the need for external concentration adjustment mechanisms and simplifying the overall process.
Solution Approach 2:
The system incorporates a feedback mechanism where the concentration of tungsten ions in the solution is monitored and controlled. The controller adjusts the solution composition based on measured tungsten concentration, ensuring optimal etching performance while managing process complexity through automated control.
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 rate of tungsten is significantly improved, with a sharp increase in etching rate observed at tungsten concentrations between 12 ppm and 100,000 ppm, enhancing productivity and throughput in semiconductor device production.
Implementation Method 1
A chemical solution having hydrogen peroxide (H2O2) as a main component is used for etching
Implementation Method 2
the chemical solution containing 12 ppm or more and 100,000 ppm or less of W... the etching rate of tungsten is significantly improved
Data Source
AI summary
An etching method according to an embodiment, includes performing etching on a material having tungsten (W) as a main component by using as an etchant a chemical solution having hydrogen peroxide as a main component. The chemical solution contains 12 ppm or more and 100,000 ppm or less of W.