Silicon Substrate Rear-Surface Polishing for Chuck Mark Removal
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Solution Overview
Problem
Conventional substrate processing methods are ineffective in removing a significant proportion of chuck marks on substrates due to poor substrate flatness, particularly caused by chuck marks formed during suction, leading to issues like defocus in extreme ultraviolet exposure devices.
Innovation Solution
A method involving a chemical liquid mixture of hydrofluoric acid and ozonated water is applied to etch and oxidize the substrate surface, followed by a polishing process using a resin-based abrasive tool to remove chuck marks and scratches, with additional chemical liquid application to further refine the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods (chemical liquid mixture with brush) are used, then the substrate surface can be cleaned, but chuck marks cannot be effectively removed
Solution Approach 1:
The invention changes the chemical composition parameters of the cleaning liquid by adding hydrofluoric acid to the conventional chemical liquid mixture (FOM), creating a new chemical formulation that can effectively dissolve silicon oxide and remove chuck marks while maintaining substrate integrity
Solution Approach 2:
The invention replaces the mechanical brush cleaning method with a chemical-based removal approach using hydrofluoric acid, which can dissolve and remove chuck marks without the mechanical contact that causes scratching and cannot effectively remove firmly attached particles
2Reliability
If strong chemical etching is applied to remove chuck marks, then particle removal improves, but substrate damage and roughness increase
Solution Approach 1:
The invention carefully controls the concentration and composition parameters of the chemical liquid mixture, using a specific formulation containing hydrofluoric acid that provides effective etching power while minimizing substrate damage through controlled chemical reactions
Solution Approach 2:
The invention uses the chemical liquid mixture as an intermediary substance that mediates between the need to remove firmly attached particles and the need to protect the substrate, enabling selective removal of chuck marks while preserving the underlying substrate structure
3Manufacturing precision
If polishing is applied after chemical cleaning, then surface smoothness improves, but processing time increases
Solution Approach 1:
The invention performs preliminary chemical cleaning and oxidation treatment before polishing, which pre-softens and prepares the substrate surface and removes loosely attached contaminants, thereby reducing the time and effort required for subsequent polishing operations
Solution Approach 2:
The invention merges multiple functions into the chemical liquid mixture treatment step, combining cleaning, oxidation, and preliminary etching operations into a single integrated process that reduces the number of separate processing steps and overall processing time
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 method effectively removes a larger proportion of chuck marks and scratches, improving substrate flatness and reducing surface roughness, thereby reducing the load on subsequent polishing processes and preventing localized etching.
Implementation Method 1
the silicon oxidizes with the ozonated water
Implementation Method 2
the oxide film (SiO) is etched with hydrofluoric acid
Data Source
AI summary
The present invention relates to a substrate processing method and a substrate processing apparatus. A substrate processing method includes:a substrate rotating step of rotating a substrate made of silicon in a horizontal orientation;a chemical liquid mixture discharging step of causing a chemical liquid nozzle to discharge a chemical liquid mixture including hydrofluoric acid and ozonated water onto a rear surface of the substrate being rotated;a polishing tool pressing step of pressing a polishing tool that has a resin body including dispersed abrasive grains, against the rear surface of the substrate being rotated, while causing a fixed nozzle to discharge a rinsing liquid onto the rear surface of the substrate being rotated, after the chemical liquid mixture discharging step; anda polishing tool moving step of moving the polishing tool between a center of the substrate and a perimeter of the substrate while the polishing tool pressing step is being performed.