Local UV Activation for Selective Silicon Etching
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Solution Overview
Problem
The challenge in semiconductor device manufacturing lies in achieving precise dimension control during the etching of silicon-based materials, particularly at the nanoscale, where existing dry etching processes face limitations in selectivity and defect generation.
Innovation Solution
A method involving a dry etching process in a chamber with a substrate covered by a patterned mask, where ultraviolet radiation with a power density greater than 6 mW/cm² is applied locally to specific portions of the substrate during etching, using techniques like RIE, IBAE, or RIBE, and alternating the radiation application to control etching selectivity and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etching processes are used for nanoscale semiconductor fabrication, then etching can be performed on silicon-based materials, but dimension control and selectivity deteriorate with scaling to single digit nanometers
Solution Approach 1:
The patent applies UV radiation locally to specific regions of the substrate during etching, creating different etching conditions in different areas. This local modification of the substrate surface through selective radiation exposure enables precise dimension control in specific regions while maintaining scalability across the entire wafer surface.
Solution Approach 2:
The patent changes the physical-chemical parameters of the substrate surface by applying UV radiation, which modifies surface properties such as reactivity and bonding characteristics. This parameter change enables better dimension control and selectivity during the etching process at nanoscale dimensions.
2Manufacturing precision
If radiation is applied to enhance etching selectivity, then etching precision improves, but process complexity increases
Solution Approach 1:
The UV radiation is applied before or during the etching process to pre-modify the substrate surface in the regions that will be etched. This preliminary action enhances etching selectivity by creating distinct surface properties in different regions, allowing for more precise pattern formation without requiring additional complex process steps.
3Productivity
If UV radiation with power density greater than 6 mW/cm² is applied locally during etching, then etching rate and selectivity improve, but surface damage may increase
Solution Approach 1:
The patent employs periodic or pulsed application of UV radiation during the etching process rather than continuous exposure. This periodic action allows for controlled modification of the substrate surface, enhancing etching rate and selectivity while providing intervals that prevent excessive surface damage and allow for thermal management.
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 enhances etching selectivity and rate, allowing for the formation of precise recesses in silicon-based substrates, which can be filled with conductive materials to create semiconductor features with improved stability and reduced surface damage.
Implementation Method 1
applying radiation locally on a portion of the substrate that is not covered by the patterned mask
Implementation Method 2
etching the portion of the substrate through a dry etching process
Data Source
AI summary
A method for manufacturing semiconductor devices is disclosed. The method includes providing, in a chamber, a substate covered by a patterned mask. The method includes applying, in the chamber, radiation locally on a portion of the substate that is not covered by the patterned mask. The method includes etching, in the chamber, the portion of the substate through a dry etching process.