Vacuum Holding Element for One-Sided Semiconductor Etching
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Solution Overview
Problem
Existing one-sided etching methods for semiconductor layers, particularly in large-area semiconductor component manufacturing, face challenges in achieving high-quality and homogeneous etching due to leakage currents and inhomogeneities caused by wet-chemical contacts and conveyor belt support systems.
Innovation Solution
A device utilizing a vacuum holding element to securely hold the workpiece opposite the etching side, with a dry contact between the second electrode and the workpiece, and a safety transport system to prevent inhomogeneities and contamination, ensuring exclusive vacuum contact and reducing the risk of electrolyte penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet-chemical contacting is used on the side of the workpiece facing away from the electrolyte, then homogeneous contact with low contact resistance is achieved, but integration into continuous flow system becomes difficult and leakage currents occur
Solution Approach 1:
The patent replaces wet-chemical contacting with a vacuum-based mechanical holding system. The vacuum holding element secures the workpiece on its holding side without requiring chemical contact, eliminating leakage currents while maintaining positioning accuracy. This substitution enables integration into continuous flow systems while preserving etching homogeneity.
Solution Approach 2:
The patent extracts the contacting function from the electrolyte environment and places it in a vacuum environment on the holding side. By separating the holding function from the etching environment, the system eliminates the source of leakage currents while maintaining workpiece stability during the etching process.
2Productivity
If conveyor belt support system is used to transport workpiece, then continuous flow processing is enabled, but inhomogeneities and contamination from contact points occur
Solution Approach 1:
The patent extracts the workpiece from contact with conveyor belt support points by using a vacuum holding element that suspends the workpiece. This eliminates contact-point inhomogeneities and contamination while maintaining continuous flow capability through the vacuum-based securing mechanism.
Solution Approach 2:
The vacuum holding element acts as an intermediary between the conveyor system and the workpiece. It provides secure holding and positioning without direct mechanical contact between the conveyor belt and workpiece surface, thereby preventing contamination and inhomogeneities while enabling continuous processing.
3Reliability
If second electrode makes wet-chemical contact with workpiece, then electrical contact is achieved, but leakage currents occur at workpiece edge leading to inhomogeneous etching
Solution Approach 1:
The patent uses a vacuum environment as an inert medium between the second electrode and the workpiece. This vacuum barrier prevents electrolyte contamination and leakage currents at the contact interface while maintaining reliable electrical contact through the vacuum holding element, thereby ensuring etching homogeneity.
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 enables high-quality, homogeneous one-sided electrochemical etching of semiconductor layers with improved process homogeneity and reduced contamination, enhancing the inline etching process for semiconductor wafer production.
Implementation Method 1
the transport device has a vacuum holding element for the workpiece, and that the vacuum holding element is designed to position the workpiece on a holding side of the workpiece opposite the etching side by means of a vacuum
Implementation Method 2
A method is known from DE 10 2013 219 886 A1 in which the workpiece is electrically contacted at the non-etched surface via a contact unit using an anode. The present invention is therefore based on the objective of improving the quality of previously known single-sided etching processes by means of electrochemical etching.
Data Source
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AI summary
The invention relates to an apparatus for etching one side of a semiconductor layer of a workpiece, comprising at least one etching basin for receiving an electrolyte, - a first electrode which is provided for electrically contacting the electrolyte that is located in the etching basin when in use, - at least one second electrode which is provided for indirectly or directly electrically contacting the semiconductor layer, - at least one electrical power source which is electrically conductively connected to the first and the second electrodes for generating an etching current, and - at least one transport apparatus for transporting the workpiece relative to the etching basin such that a semiconductor layer etching face to be etched can be wetted by the electrolyte that is located in the etching basin when in use. The invention is characterised in that the transport apparatus has a negative pressure retaining element for the workpiece, said negative pressure retaining element being designed to position the workpiece on a retaining face of the workpiece opposite to the etching face by means of negative pressure, and in that the second electrode is positioned on the negative pressure retaining element such that, when the workpiece is positioned on the negative pressure retaining element, the retaining face of the workpiece is contacted by means of the second electrode. The invention also relates to a method for etching one side of a semiconductor layer of a workpiece.