Semiconductor Wafer Reclamation via Direct Ionic Vaporization
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Solution Overview
Problem
The semiconductor industry faces challenges in safely and cost-effectively reclaiming or recycling patterned wafers while protecting intellectual property, as conventional methods are labor-intensive, environmentally unfriendly, and risk intellectual property disclosure.
Innovation Solution
A method and system utilizing coherent light with specific wavelength, power, pulse width, and pulse rate for direct ionic vaporization of materials on semiconductor substrates, allowing for complete removal of patterns and materials without thermal damage or contamination, enabling the reuse of substrates as test wafers or carrier wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional reclamation methods are used to remove materials from semiconductor substrates, then complete removal of patterns is achieved, but the process is labor-intensive and time-consuming
Solution Approach 1:
The patent replaces mechanical reclamation methods with a light-based system. A laser or other coherent light source is used to irradiate the semiconductor substrate, causing photothermal decomposition of the resist and organic materials. This optical method eliminates manual labor and significantly increases processing speed while achieving complete pattern removal.
Solution Approach 2:
The patent changes the physical state and chemical composition of materials through controlled light irradiation. By adjusting light intensity, wavelength, and exposure time, the system selectively decomposes organic materials and removes metals through photochemical reactions, enabling automated high-speed reclamation without mechanical contact.
2Manufacturing precision
If conventional reclamation methods are used, then materials are removed from substrates, but hazardous chemicals and environmental pollution are generated
Solution Approach 1:
The patent replaces chemical etching and solvent-based cleaning with photothermal and photochemical decomposition. The laser light directly breaks down organic materials and volatilizes metals without requiring hazardous chemicals, eliminating toxic waste and environmental pollution while achieving complete material removal.
Solution Approach 2:
The patent converts the harmful effect of intense light (which could cause substrate damage) into a beneficial process by controlling the irradiation parameters. The photothermal effect that could overheat the substrate is instead used to selectively decompose and remove only the patterned materials, leaving the substrate intact and reusable.
3Manufacturing precision
If conventional reclamation methods are used, then patterns are removed from substrates, but intellectual property disclosure risk increases
Solution Approach 1:
The patent uses light irradiation to completely vaporize and decompose the patterned materials on the substrate. This thorough photothermal decomposition ensures that no trace of the original semiconductor patterns remains, effectively destroying intellectual property information and preventing any possibility of disclosure during the reclamation process.
4Productivity
If intensive light irradiation is used for rapid material removal, then processing speed increases, but substrate temperature rises causing damage
Solution Approach 1:
The patent applies light irradiation locally and selectively to only the areas containing patterns that need removal. The laser is focused on the resist and organic material layers, causing photothermal decomposition only in those regions. The substrate bulk remains relatively cool because the energy is concentrated on the surface materials, enabling fast processing without thermal damage.
Solution Approach 2:
The patent uses pulsed or intermittent light irradiation rather than continuous exposure. This periodic action allows brief intervals for heat dissipation between pulses, preventing cumulative thermal buildup in the substrate while maintaining high overall processing speed through rapid successive removal cycles.
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
Enables safe, non-hazardous, and green recycling of patterned wafers, ensuring complete removal of intellectual property and achieving a mirror-like finish, thus reducing costs and environmental impact while safeguarding proprietary information.
Implementation Method 1
focusing coherent light on a surface of a semiconductor substrate. The coherent light has a predetermined wavelength, power, pulse width, and pulse rate or number of pulses per unit area that causes direct ionic vaporization of material formed in or on the surface of the substrate
Data Source
AI summary
Reclamation or recycling of a semiconductor workpiece includes vaporizing the structures and materials deposited, implanted, or formed in or on the substrate with minimally acceptable damage to the crystalline substrate through direct ionic vaporization rather than thermal ablation. The purity of the substrate therefore remains substantially free from heavy metal surface contamination and has a surface roughness that may be polished back to a mirror-like finish using chemical mechanical polishing or lapping processes. The process includes focusing coherent light on a surface of the substrate with a predetermined wavelength, power, pulse width, and pulse rate or number of pulses per unit area that causes direct ionic vaporization of material formed in or on the surface of the substrate up to a predetermined penetration depth. Advantageously, patterned, previously used test, and out of specification wafers may be reclaimed for reuse or recycled without risk of the unintended disclosure of intellectual property.