Wafer-Bonded Semiconductor Etching Without Light-Field Bias
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Solution Overview
Problem
Existing semiconductor substrate processing methods require strong light illumination and transverse electric fields or complex methods like the Hall effect to facilitate electrochemical etching, which affects reliability due to environmental variables.
Innovation Solution
A semiconductor substrate processing method involving wafer bonding to create a temporary PN junction structure, allowing for rapid electrochemical etching without the need for light sources or biased electromagnetic fields, using a P-type semiconductor substrate as a hole supply to facilitate anodizing reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong light illumination and transverse electric fields are applied to facilitate electrochemical etching, then the electrochemical reaction can proceed, but the reliability is affected due to environmental variables such as distances and intensities
Solution Approach 1:
The invention extracts and eliminates the light source and electromagnetic field system from the electrochemical etching process. By using a direct contact method where the semiconductor substrate is placed in electrolyte without requiring external light illumination or transverse electric fields, the patent removes the environmental variables (distances, intensities) that affect reliability, thereby achieving consistent etching results through pure chemical dissolution.
Solution Approach 2:
The invention introduces an intermediary substance (electrolyte) that mediates the etching process. Instead of using light or electromagnetic fields to drive the reaction, the electrolyte directly contacts the semiconductor substrate and facilitates electrochemical dissolution through ionic conduction, eliminating the need for complex external field application systems.
2Productivity
If conventional electrochemical etching methods are used without wafer bonding, then the process is simpler, but the etching speed is slow and productivity is low
Solution Approach 1:
The invention merges two substrates (semiconductor substrate and sacrificial substrate) through wafer bonding to create a combined structure that enables rapid electrochemical etching. The sacrificial substrate acts as a counter electrode, establishing an electrochemical cell that dramatically accelerates the etching speed compared to conventional methods, while the bonded structure allows for systematic process control.
Solution Approach 2:
The invention changes the electrochemical parameters by creating a direct electrochemical cell through wafer bonding. The sacrificial substrate serves as a counter electrode, enabling high current density and rapid material removal. This parameter change (from low-speed conventional etching to high-speed electrochemical etching) is achieved through the bonded structure that facilitates efficient ionic and electronic conduction.
3Productivity
If impurities are introduced during the electrochemical etching process, then the etching can proceed, but chemical pollution increases
Solution Approach 1:
The invention creates a controlled chemical environment using specific electrolyte compositions that minimize harmful byproducts. The electrochemical etching process is conducted in an electrolyte solution that promotes clean dissolution of the semiconductor material while minimizing the generation of toxic or harmful chemical substances, thereby reducing chemical pollution while maintaining high etching efficiency.
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
This method enables efficient and reliable rapid electrochemical etching with reduced chemical pollution, allowing for easy separation and recycling of substrates, and is applicable to various semiconductor substrates including high-impedance silicon crystals.
Implementation Method 1
the hole supply substrate provides holes for the solid-liquid contact surface so as to complete an anodizing reaction
Implementation Method 2
the hole supply substrate provides holes for the solid-liquid contact surface so as to complete an anodizing reaction, thereby forming a reaction layer on the side to be processed
Implementation Method 3
bonding the hole supply substrate to the bonding side of the substrate to be processed by means of a wafer bonding process
Data Source
AI summary
A semiconductor substrate processing method includes: providing a substrate to be processed, where the substrate to be processed has a side to be processed and a bonding side which are opposite to each other; providing a hole supply substrate; and bonding the hole supply substrate to the bonding side of the substrate to be processed by a wafer bonding process so as to obtain a substrate pair, and performing a material process. By the semiconductor substrate processing method, the purpose of rapid electrochemical etching can be achieved.