Electro-chemical Processor With Pivotable Housing And LED Illumination
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Solution Overview
Problem
Existing porous silicon processors face challenges in achieving uniform processing, reliability, and contamination prevention due to the use of corrosive hydrofluoric acid and the complexity of achieving uniform electrical current flow and lighting, especially in compact designs.
Innovation Solution
A novel processor design with a pivotable housing, sealed electrodes, and controlled electrolyte flow, allowing for compact and efficient processing with reduced contamination risks, featuring a lamp configuration for uniform lighting and precise current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If large high power tungsten halogen lamps are positioned relatively far from the wafer to illuminate the wafer, then the wafer receives sufficient light, but excessive electrical power is consumed and excessive heat is generated
Solution Approach 1:
The patent replaces traditional large high power tungsten halogen lamps with light emitting diodes (LEDs) as the illumination source. LEDs consume significantly less electrical power while providing sufficient illumination intensity for the wafer, directly resolving the contradiction between adequate lighting and excessive power consumption
Solution Approach 2:
The invention changes the illumination parameters by using multiple lower power LED sources positioned at optimized distances and angles from the wafer, rather than relying on a single distant high power lamp. This distribution of illumination sources maintains adequate lighting while dramatically reducing total power consumption and heat generation
2Illumination intensity
If large high power tungsten halogen lamps are used to illuminate the wafer, then sufficient light is provided, but excessive heat is generated which may affect the process liquid
Solution Approach 1:
The patent substitutes LED illumination sources for traditional high power tungsten halogen lamps. LEDs generate minimal heat compared to incandescent lamps, thereby illuminating the wafer adequately without generating excessive heat that would affect the process liquid temperature
Solution Approach 2:
The invention introduces optical elements such as lenses and reflectors as intermediaries to efficiently direct and distribute LED light to the wafer. These optical components maximize light delivery while minimizing heat transfer to the process liquid, maintaining temperature control
3Strength
If metals are used in areas of the processor that may come into contact with HF, then structural strength is provided, but the HF will react with the metals and contaminate the wafer
Solution Approach 1:
The patent introduces non-metallic sealing materials and coatings as intermediaries between metal structural components and the hydrofluoric acid electrolyte. These intermediary layers provide the necessary structural strength while preventing direct contact between HF and metals, thereby eliminating metal contamination of the wafer
Solution Approach 2:
The invention creates a chemically inert environment by using HF-resistant non-metallic materials (such as fluoropolymers and ceramic coatings) to line and seal all areas where the electrolyte contacts processor components. This inert barrier system maintains structural integrity while preventing harmful chemical reactions and contamination
4Manufacturing precision
If the processor is designed to provide uniform electrical current flow through the electrolyte, then high quality porous silicon is produced, but the design becomes more complex and challenging to achieve
Solution Approach 1:
The patent applies local quality by designing electrodes with spatially varying properties - specifically, non-uniform thickness or conductivity distribution across the electrode surface. This local variation compensates for edge effects and ensures uniform current density across the entire wafer surface, achieving high quality porous silicon without overly complex overall design
Solution Approach 2:
The invention segments the electrode into multiple zones or sections with different geometric or electrical characteristics. This segmentation allows independent optimization of current distribution in different areas, achieving uniform current flow through controlled variation rather than uniform design
5Volume of moving object
If the processor is designed for compact format, then space efficiency is improved, but achieving uniform lighting and uniform current flow becomes more difficult
Solution Approach 1:
The patent employs a nested arrangement where multiple functional components are integrated within each other - LEDs are positioned within or near the electrode structure, optical elements are integrated into the chamber walls, and sealing components are incorporated into the electrode mounting. This nesting achieves compact volume while maintaining proper spacing and alignment for uniform processing
Solution Approach 2:
The invention designs components to serve multiple functions simultaneously - for example, the electrode structure provides both electrical current distribution and mechanical support for lighting components, while chamber walls provide both containment and optical pathways. This multi-functionality reduces the number of separate components needed, achieving compact design without sacrificing processing uniformity
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 processor achieves highly uniform and reliable porous silicon production with reduced maintenance and contamination risks, enabling rapid and consistent processing in a compact format.
Implementation Method 1
a lamp configured to emit light onto the wafer
Implementation Method 2
Electrical current is passed through the electrolyte on each side, making one side the cathode and the other side the anode
Implementation Method 3
The process etches pores in the wafer. The pores are microscopic. A 150 mm diameter wafer may have more than 1 billion pores after electro-chemical processing
Data Source
AI summary
A processor for making porous silicon or processing other substrates has first and second chamber assemblies. The first and second chamber assemblies include first and second seals for sealing against a wafer, and first and second electrodes, respectively. The first and/or second seal is moveable towards and away from a wafer in the processor, to move between a wafer load/unload position, and a wafer process position. The first electrode may move along with the first seal, and the second electrode may move along with the second seal. A light source shines light onto the first side of the wafer. The processor may be pivotable from a substantially horizontal orientation, for loading and unloading a wafer, to a substantially vertical orientation, for processing a wafer.