Ozone-Enhanced HF Substrate Cleaning for High Throughput
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Solution Overview
Problem
The existing substrate cleaning methods using SC1 solution have low etching capability due to weak oxidative power, resulting in inefficient removal of foreign matter, requiring longer processing times and reducing throughput.
Innovation Solution
A substrate processing method involving an ozone-containing hydrofluoric acid solution is used, where ozone is dissolved in hydrofluoric acid to form a silicon oxide film on the substrate, which is then peeled off, combined with a brush-cleaning step to efficiently remove foreign matter and flaws, while maintaining the surface hydrophilicity to prevent re-adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SC1 (ammonia/hydrogen peroxide mixture liquid) is used as the cleaning chemical liquid, then the substrate can be cleaned by oxidizing the major surface to form a silicon oxide film, but the oxidative power is relatively weak and the etching capability is not so high, resulting in low cleaning efficiency
Solution Approach 1:
The patent replaces the weak oxidant (hydrogen peroxide in SC1) with a strong oxidant (ozone). The ozone-containing cleaning liquid rapidly oxidizes the silicon substrate surface to form a thick silicon oxide film, significantly enhancing the etching capability and foreign matter removal efficiency, thereby resolving the contradiction between cleaning effectiveness and throughput
Solution Approach 2:
The patent changes the chemical composition parameters of the cleaning liquid by introducing ozone (at a concentration of 1-50 ppm) into the hydrofluoric acid-based cleaning liquid. This parameter change transforms the cleaning mechanism from weak oxidation to strong oxidation, enabling rapid oxide film formation and removal, thus improving both cleaning effectiveness and processing speed
2Manufacturing precision
If the major surface is scrubbed with the cleaning brush while SC1 is supplied, then foreign matter can be removed, but the cleaning efficiency remains low when a greater amount of foreign matter adheres to the surface, requiring longer processing periods
Solution Approach 1:
The use of ozone as a strong oxidant enables rapid formation of a thick silicon oxide film that encapsulates foreign matter particles. When combined with brush scrubbing, this accelerates the removal process significantly compared to conventional SC1 cleaning, reducing the time required to achieve high surface cleanliness even when heavy contamination is present
Solution Approach 2:
The ozone-containing cleaning liquid performs preliminary oxidation and oxide film formation before the brush scrubbing action. This preliminary action weakens the adhesion of foreign matter to the substrate surface, making the subsequent brush cleaning more effective and faster, thereby reducing total processing time while maintaining high cleanliness standards
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 method significantly enhances the cleaning efficiency by forming and removing a greater amount of oxide film, effectively removing foreign matter and flaws, and prevents re-adhesion, thereby improving throughput and cleaning effectiveness.
Implementation Method 1
An oxide film is formed in the one major surface of the substrate by the oxidizing action of ozone contained in the ozone-containing hydrofluoric acid solution
Implementation Method 2
the oxide film formed in the one major surface of the substrate is peeled off (lifted off) from the one major surface by the oxide film etching action of hydrofluoric acid contained in the ozone-containing hydrofluoric acid solution
Data Source
AI summary
A substrate processing method is provided, which includes: an ozone-containing hydrofluoric acid solution spouting step of spouting an ozone-containing hydrofluoric acid solution containing ozone dissolved therein from a nozzle toward one major surface of a substrate held by a substrate holding unit; and a brush-cleaning step of cleaning the one major surface of the substrate by bringing a cleaning brush into abutment against the one major surface of the substrate, the brush-cleaning step being performed after the ozone-containing hydrofluoric acid solution spouting step or in parallel with the ozone-containing hydrofluoric acid solution spouting step.