SiC Substrate Anodization With Pulsed Current for Faster Polishing
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Solution Overview
Problem
Conventional ECMP methods for processing SiC substrates face limitations in processing speed due to saturation of the oxidation rate during anodization, primarily because of insufficient supply of reactive species (OH-) in the near-surface region, leading to inefficient processing characteristics.
Innovation Solution
A surface processing apparatus and method that employs a pulsed current with a period greater than 0.01 seconds and up to 20 seconds for anodization, combined with a grinding wheel layer to selectively remove the oxide film, enhancing the processing characteristics by improving oxidation rate, polishing speed, and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ECMP methods are used for processing SiC substrates, then the oxidation rate saturates due to insufficient supply of reactive species (OH-) in the near-surface region, but the processing speed remains limited
Solution Approach 1:
The patent applies pulsed current with a period greater than 0.01 seconds and up to 20 seconds for anodization. This periodic action allows the reactive species (OH-) to be supplied intermittently, preventing saturation and maintaining efficient oxidation rates throughout the processing cycle, thereby resolving the contradiction between processing speed and reactive species supply
2Productivity
If the oxidation rate is increased to improve processing speed, then the supply of reactive species becomes insufficient, leading to saturation
Solution Approach 1:
By using pulsed current with periods greater than 0.01 seconds, the system creates periodic intervals where reactive species can be supplied to the near-surface region. This prevents continuous consumption and saturation, allowing the oxidation rate to remain high without depleting the reactive species supply
3Productivity
If conventional continuous current is used for anodization, then the processing efficiency is reduced, but the apparatus complexity remains low
Solution Approach 1:
The patent implements pulsed current control with periods greater than 0.01 seconds, which significantly improves processing efficiency by preventing oxidation rate saturation. The relatively long period requirement simplifies the control system design compared to high-frequency pulsing, as it allows for easier timing control and reduces the need for complex high-speed switching circuits
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 pulsed current approach significantly increases processing speed, reduces manufacturing costs, and improves the flatness and uniformity of the SiC substrate surface, offering superior processing characteristics compared to conventional methods.
Implementation Method 1
anodizing a workpiece surface of a SiC substrate by passing a pulsed current through the SiC substrate as an anode in the presence of an electrolyte
Implementation Method 2
The anodizing process is a process for forming an oxide film is on the surface of a workpiece by applying a voltage to the workpiece as an anode in the presence of an electrolyte to produce a current flow
Implementation Method 3
The polishing process is a process for selectively polishing and removing the oxide film by using a polishing material having a Mohs hardness that is an intermediate hardness between that of the workpiece and that of the oxide film
Data Source
AI summary
Provided is a surface processing apparatus and a surface processing method for a SiC substrate using anodization. The surface processing apparatus for the SiC substrate includes a surface processing pad and a power supply device. The surface processing pad includes a grinding wheel layer. The grinding wheel layer is disposed facing a workpiece surface of the SiC substrate. The power supply device passes a pulsed current having a period greater than 0.01 seconds and less than or equal to 20 seconds for anodizing the workpiece surface to be processed by the grinding wheel layer through the SiC substrate as an anode in the presence of an electrolyte.