Variable Current Source for Single-Sided Semiconductor Wafer Etching
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Solution Overview
Problem
Existing methods for one-sided etching of semiconductor layers are prone to errors and limited in application, particularly due to inhomogeneities at the edges of the semiconductor layer during the etching process, and are not suitable for high-throughput industrial processes.
Innovation Solution
A device and method that utilize a variable current source and a control unit to automatically adjust the etching current based on sensor data, ensuring a constant etching current density and modulating the current profile to prevent edge inhomogeneities, allowing for the formation of targeted inhomogeneous layers and expanding the application range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant current source is used for etching, then the etching process is simple to operate, but edge inhomogeneities occur due to varying wetted surface area
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a constant current source to a variable current source that dynamically adjusts the etching current based on the wetted surface area of the semiconductor layer. The control unit continuously monitors and modifies the current to maintain constant current density, thereby eliminating edge inhomogeneities while preserving operational simplicity.
Solution Approach 2:
The patent implements feedback control by using a control unit that receives information about the wetted surface area and adjusts the etching current accordingly. This closed-loop feedback system ensures that the current density remains constant throughout the etching process, preventing edge effects and maintaining manufacturing precision.
2Productivity
If the semiconductor layer is moved in and out of the etching chamber, then high-throughput production is enabled, but edge inhomogeneities and process errors increase
Solution Approach 1:
The patent applies preliminary action by pre-programming the variable current source with specific current profiles that anticipate the entry and exit of the semiconductor layer into the etching chamber. The control unit is configured to automatically adjust the current during these transition phases, preventing edge inhomogeneities before they occur and ensuring reliable high-throughput processing.
Solution Approach 2:
The patent uses dynamics by implementing time-dependent current profiles that adapt to the positional state of the semiconductor layer. The etching current is dynamically modulated based on whether the layer is entering, fully immersed, or exiting the chamber, thereby maintaining process reliability during high-speed cyclic operations.
3Adaptability or versatility
If only one side of the semiconductor layer is wetted with electrolyte, then one-sided etching is achieved, but application range is limited
Solution Approach 1:
The patent applies parameter changes by systematically varying the etching current as a function of time and wetted surface area. The variable current source enables different current profiles to be applied for different processing requirements, expanding the application range while maintaining etching uniformity through the fundamental principle of constant current density 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 solution reduces susceptibility to errors and increases the application range by ensuring homogeneous etching across the semiconductor layer, enabling the production of layers with varying porosity and properties, suitable for high-throughput industrial processes.
Implementation Method 1
the electrolyte is designed in such a way that, in cooperation with the etching current which flows between the two electrodes and thus also between the electrolyte and the semiconductor layer, the semiconductor layer is etched in the region which is wetted with the electrolyte
Data Source
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AI summary
The invention relates to an apparatus for etching one side of a semiconductor layer, comprising at least one etching tank for receiving an electrolyte, a first electrode, which is arranged to make electrical contact with the electrolyte located in the etching tank during use, at least a second electrode, which is arranged to make indirect or direct electrical contact with the semiconductor layer, at least one electric current source, which is electrically conductively connected to the first and the second electrode to produce an etching current, and at least one transport apparatus for transporting the semiconductor layer relative to the etching tank in such a way that substantially only an etching side of the semiconductor layer that is to be etched can be wetted by the electrolyte located in the etching tank during use. The invention is characterized in that the current source is formed as a variable current source, and that the apparatus has a control unit for controlling the variable current source, wherein the apparatus is designed such that the etching current can be changed automatically by means of the control unit during the etching operation. The invention further relates to a method for etching one side of a semiconductor layer.