Batch Porous Silicon Reactor Design for High-Throughput Manufacturing
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Solution Overview
Problem
Current porous silicon manufacturing equipment lacks high-throughput and cost-effectiveness, leading to high capital costs, excessive electrical power consumption, and yield losses due to single-wafer processing and serial processing times.
Innovation Solution
The development of batch processing architecture for porous silicon manufacturing, allowing multiple wafers to be processed simultaneously in a single reactor with shared electrolyte bath and optimized electrode design for uniform electric field distribution, reducing capital costs and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If single-wafer processing is used, then equipment simplicity is maintained, but productivity is low and capital costs are high
Solution Approach 1:
The processing system is segmented into multiple independent wafer processing zones arranged in series, with each zone handling one wafer. This allows parallel processing of multiple wafers while maintaining relatively simple individual zone designs, thereby increasing throughput without proportionally increasing overall system complexity
Solution Approach 2:
Multiple wafer processing operations are merged into a single integrated reactor system with shared electrolyte circulation and power supply components. This combining approach enables simultaneous processing of multiple wafers while avoiding the need for separate complete processing systems for each wafer, thus improving productivity without linearly increasing capital costs
2Use of energy by moving object
If single-wafer processing is used, then process control is simple, but electrical power consumption is excessive
Solution Approach 1:
The electrolyte circulation system and power supply are merged and shared across multiple wafer processing zones. A single electrolyte pump circulates electrolyte through all zones, and a shared power supply unit provides current to multiple wafers simultaneously. This reduces total power consumption compared to operating separate processing systems for each wafer, while enabling higher manufacturing throughput through parallel processing
Solution Approach 2:
The electrolyte circulation system is designed with multi-functionality to serve multiple wafer processing zones simultaneously. The same electrolyte reservoir, pump, and filtration system handle electrolyte supply, circulation, and waste removal for all processing zones, reducing the total energy required for electrolyte management across the entire system
3Productivity
If batch processing with multiple wafers is implemented, then productivity increases, but uniform electric field distribution becomes difficult to achieve
Solution Approach 1:
The electrode design incorporates local quality variations to compensate for non-uniform electric field distribution in batch processing. The electrode geometry, spacing, or conductivity is locally adjusted in different zones of the reactor to ensure that each wafer receives a uniform effective electric field, thereby maintaining consistent porous silicon layer quality across all wafers processed in batch while enabling high throughput
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 approach significantly reduces capital costs, minimizes electrical power consumption, and enhances productivity by enabling efficient handling and processing of multiple wafers, thereby making porous silicon production more viable for large-scale industrial applications.
Implementation Method 1
The electrolyte for porous silicon is, for example: HF (49% in H2O typically), isopropyl alcohol (IPA) (and/or acetic acid), and deionized water (DI H2O). Additional additives such as certain salts may be used to enhance the electrical conductivity of the electrolyte
Implementation Method 2
Porous silicon is created by the electrochemical etching of silicon wafers with appropriate doping in an electrolyte bath
Implementation Method 3
IPA (and/or acetic acid) serves as a surfactant and assists in the uniform creation of PS
Implementation Method 4
optimized electrode design for uniform electric field distribution
Data Source
AI summary
This disclosure enables high-productivity fabrication of porous semiconductor layers (made of single layer or multi-layer porous semiconductors such as porous silicon, comprising single porosity or multi-porosity layers). Some applications include fabrication of MEMS separation and sacrificial layers for die detachment and MEMS device fabrication, membrane formation and shallow trench isolation (STI) porous silicon (using porous silicon formation with an optimal porosity and its subsequent oxidation). Further, this disclosure is applicable to the general fields of photovoltaics, MEMS, including sensors and actuators, stand-alone, or integrated with integrated semiconductor microelectronics, semiconductor microelectronics chips and optoelectronics.