pH and Redox Potential Water Production for Semiconductor Etching
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Solution Overview
Problem
Conventional ultra-fine etching techniques for semiconductors, such as digital etch, face challenges in achieving consistent metal loss and surface roughness, leading to deteriorated electrical characteristics and performance issues due to varying wiring widths and treatment times.
Innovation Solution
A pH/redox potential-adjusted water production apparatus that controls pH and redox potential by adding specific adjusters to ultrapure water, allowing for precise control of metal dissolution rates, using mechanisms like hydrogen peroxide removal, branched flow paths, and monitoring systems to produce tailored cleaning solutions for semiconductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional digital etch process is used with extremely dilute APM and carbonated water, then ultra-fine etching can be performed, but treatment time becomes excessively long (about 20 minutes) and pattern loading occurs
Solution Approach 1:
The invention changes the chemical parameters of the etching solution by adjusting pH to 9-13 and redox potential to 0-1.7V, replacing the conventional dilute APM formulation. This parameter adjustment enables significantly faster etching rates while maintaining precise metal loss control and eliminating pattern loading effects
Solution Approach 2:
The invention introduces dynamic control of multiple parameters (pH, redox potential, temperature, concentration) that can be adjusted in real-time during the etching process. This allows the system to adapt to different wiring widths and achieve consistent etching results regardless of pattern size
2Manufacturing precision
If conventional digital etch process is used, then ultra-fine etching can be performed, but metal loss varies depending on wiring width (pattern loading)
Solution Approach 1:
By adjusting pH to 9-13 and redox potential to 0-1.7V, the invention creates an etching environment where the dissolution rate becomes independent of pattern size. This chemical parameter optimization eliminates pattern loading and achieves constant metal loss across different wiring widths
Solution Approach 2:
The invention implements monitoring mechanisms that measure water quality parameters (pH, redox potential, temperature, concentration) and provide feedback to the control system. This allows real-time adjustments to maintain consistent etching performance across varying wiring widths
3Manufacturing precision
If conventional digital etch process is used, then ultra-fine etching can be performed, but surface roughness increases and electrical characteristics deteriorate
Solution Approach 1:
The invention optimizes chemical parameters (pH 9-13, redox potential 0-1.7V) to achieve controlled metal dissolution that maintains surface smoothness. This parameter control prevents excessive roughness formation while achieving the required metal loss, thereby preserving electrical characteristics
Solution Approach 2:
The invention replaces the mechanical/physical etching mechanism with a chemically-controlled process. By using pH and redox potential control, the etching becomes a controlled chemical reaction rather than a mechanical removal process, resulting in smoother surfaces and better electrical properties
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
Enables consistent metal loss of 10 nm in a short treatment time regardless of wiring width, reducing surface roughness and improving semiconductor performance by suppressing cobalt dissolution through tailored pH and redox potential adjustments.
Implementation Method 1
a hydrogen peroxide removal mechanism provided in an ultrapure water supply line
Implementation Method 2
a pH adjusting mechanism that adds the pH adjuster
Implementation Method 3
a redox potential adjusting mechanism that adds the redox potential adjuster
Implementation Method 4
oxidization and dissolution of the metal surface is repeated to gradually remove the wiring metal
Data Source
AI summary
The pH/redox potential-adjusted water production apparatus includes a supply line for ultrapure water, which is provided with a platinum group metal-supporting resin column. The ultrapure water supply line is branched downstream into a first adjusted water production line and a second adjusted water production line. The first adjusted water production line communicates with a pH adjuster tank and a redox potential adjuster tank, and a first reservoir is provided downstream from them. The second adjusted water production line communicates with a pH adjuster tank and a redox potential adjuster tank, and a second reservoir is provided downstream from them. With such a pH/redox potential-adjusted water production apparatus, it is possible to dissolve a predetermined amount of wiring metal in a wiring production step for semiconductors in which a transition metal such as cobalt is used as the wiring metal.