Vacuum Chuck Pressure Switching to Limit Substrate Distortion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate holding methods using vacuum suction cause stress and distortion in substrates, and existing solutions to improve throughput are disadvantageous.
Innovation Solution
A substrate holding apparatus with a chuck that performs a first exhaust operation at a high pressure to prevent substrate sideslipping, followed by a second exhaust operation at a lower pressure to reduce distortion, ensuring precise contact and improved throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum suction is applied to hold the substrate, then the substrate can be securely held, but stress acts on the substrate causing distortion
Solution Approach 1:
The exhaust pressure is changed in two stages: first at a high pressure to prevent sideslipping, then at a lower pressure to reduce distortion. This parameter change resolves the contradiction by adjusting the holding force to balance security and precision.
Solution Approach 2:
The exhaust operation is divided into two periodic stages: a first exhaust operation at high pressure followed by a second exhaust operation at low pressure. This periodic action allows the system to first secure the substrate, then reduce distortion while maintaining holding reliability.
2Manufacturing precision
If the clamp force is reduced after a given time, then substrate distortion is reduced, but throughput is disadvantaged
Solution Approach 1:
Instead of temporarily reducing clamp force after a given time, the patent implements periodic exhaust operations with two distinct pressure stages. The first high-pressure stage ensures secure holding for quick substrate acquisition, while the second low-pressure stage reduces distortion, achieving both productivity and precision without time-based delays.
Solution Approach 2:
The exhaust pressure parameter is dynamically changed from high to low during the holding process. This parameter change allows the system to maintain high throughput by avoiding temporary force reduction delays, while still achieving low distortion through the second low-pressure exhaust stage.
3Reliability
If high exhaust pressure is used, then substrate sideslipping is prevented, but substrate distortion increases
Solution Approach 1:
The exhaust process is divided into two periodic stages: first using high pressure to prevent sideslipping and ensure positioning accuracy, then switching to low pressure to reduce distortion. This periodic action sequence resolves the contradiction by applying high pressure only when needed for positioning, then reducing it for flatness.
Solution Approach 2:
The exhaust pressure parameter is changed from high to low in sequence. The high pressure stage ensures substrate positioning accuracy by preventing sideslipping, while the subsequent low pressure stage reduces distortion. This parameter change strategy achieves both positioning accuracy and flatness without compromise.
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
Simultaneously reduces substrate distortion and improves throughput by controlling exhaust pressure transitions during the holding process.
Implementation Method 1
A manufacturing process for semiconductor devices, liquid crystal display devices, and the like uses a chuck that holds a substrate by vacuum suction
Data Source
AI summary
The present invention provides a substrate holding apparatus that holds a substrate, comprising: a chuck configured to support the substrate; pins configured to protrude from the chuck; a controller configured to control exhaust of a space between the substrate and the chuck, wherein the controller is configured to control the exhaust to perform a first exhaust operation of exhausting gas from the space with a first exhaust pressure, and after the first exhaust operation, perform a second exhaust operation of exhausting gas from the space with a second exhaust pressure lower than the first exhaust pressure, and wherein the second exhaust operation is performed in a period from when a protrusion amount of the pins start to decrease until when the chuck and the substrate come into contact with each other.