Fluid-Based Indentation Detection for Substrate Polishing
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Solution Overview
Problem
Existing methods for detecting the position of indentations on substrates, such as photoelectric sensors and cameras, face challenges in accuracy due to processing liquids and corrosion issues, especially when dealing with substrates like Cu that corrode under light exposure.
Innovation Solution
A substrate processing apparatus equipped with a fluid injection nozzle, a fluid measuring device, and a position detector that measures physical quantities like pressure or flow rate to accurately detect indentation positions on the substrate's circumferential edge, regardless of the detection environment, using a fluid like pure water, clean air, or N2 gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photoelectric sensors or cameras are used to detect indentation positions, then the detection can be performed visually, but the detection accuracy deteriorates due to processing liquids and corrosion issues especially with Cu substrates under light exposure
Solution Approach 1:
The patent replaces optical detection systems (photoelectric sensors and cameras) with a fluid-based detection system. Instead of using light to detect indentation positions, the invention uses a fluid jet that interacts with the substrate surface, and detects position changes through pressure or flow rate measurements. This mechanical/fluid-based approach eliminates the harmful effects of light exposure on Cu substrates and interference from processing liquids.
Solution Approach 2:
The invention employs a fluid jet (pneumatic or hydraulic system) to detect indentation positions. A nozzle directs a fluid stream at the substrate's circumferential edge, and when an indentation is detected, it causes a measurable change in fluid pressure or flow rate. This pneumatic/hydraulic detection method provides accurate position detection without the corrosion and interference problems associated with optical methods in wet processing environments.
2Device complexity
If optical methods are used for detection, then the setup is simple, but the reliability deteriorates in environments with processing liquids and corrosive materials
Solution Approach 1:
The invention uses a fluid jet system that is inherently more reliable in wet and corrosive environments compared to optical systems. The fluid-based detection method is not affected by processing liquids or corrosive materials that would interfere with or damage optical components, providing consistent and reliable detection throughout the substrate processing workflow.
3Ease of operation
If light-based detection is used on Cu substrates, then the detection process is straightforward, but the substrate suffers from corrosion under light exposure
Solution Approach 1:
The patent replaces the light-based detection process with a fluid-based mechanical detection system. Instead of exposing the Cu substrate to light that causes corrosion, a fluid jet is directed at the substrate surface and detects indentation positions through pressure or flow rate changes. This eliminates the harmful light-substrate interaction while maintaining detection functionality.
Solution Approach 2:
The fluid jet acts as an intermediary between the detection system and the substrate. Rather than light directly interacting with the Cu substrate and causing corrosion, the fluid serves as a mediator that transfers detection information through measurable pressure or flow rate changes, protecting the substrate from harmful effects while enabling accurate detection.
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 solution allows for precise detection of indentation positions on substrates, unaffected by environmental factors or liquid interference, ensuring accurate processing and polishing operations.
Implementation Method 1
a fluid injection nozzle configured to inject a fluid to a circumferential edge portion of the substrate when the substrate is held on the substrate stage
Implementation Method 2
a fluid measuring device configured to measure a physical quantity which is pressure or a flow rate of the fluid
Data Source
AI summary
A polishing device has a substrate stage which holds a substrate Wf, a processing head which processes a surface of the substrate Wf, an indentation detecting system which detects a position of an indentation in the substrate Wf, a movement mechanism which moves the processing head in a radial direction of the substrate stage, and a rotation mechanism which rotates the substrate stage, and the indentation detecting system has a fluid injection nozzle configured to inject a fluid to a circumferential edge portion of the substrate Wf when the substrate Wf is held on the substrate stage, a fluid measuring device which measures a physical quantity which is pressure or a flow rate of the fluid, and a position detector which detects the position of the indentation formed in the circumferential edge portion of the substrate Wf based on a change in physical quantity.