Air Bearing Substrate Registration via Pneumatic Positioning
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Solution Overview
Problem
Current integrated circuit fabrication methods rely on assumptions about chuck flatness and substrate geometry, leading to inaccuracies in tool alignment and limited response times for auto-focus mechanisms, which are costly and insufficient for high-throughput demands.
Innovation Solution
A tool with an air bearing system that uses a pressure source and vacuum source to maintain a consistent distance between the substrate and the tool head, eliminating the need for costly auto-focus mechanisms by allowing precise registration of the substrate's upper surface without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an active focusing mechanism is used to compensate for height changes, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces the mechanical auto-focus mechanism with a pneumatic system consisting of an air bearing, pressure source, and vacuum source. This substitution eliminates complex mechanical moving parts while achieving the same function of maintaining precise substrate-to-head distance, thereby reducing device complexity and cost while preserving measurement precision.
Solution Approach 2:
The patent employs pneumatic principles by using an air bearing with pressure and vacuum sources to control the distance between the substrate and tool head. The pressure source pushes the substrate away from the air bearing while the vacuum source draws it toward, creating a balanced pneumatic system that maintains precise positioning without mechanical contact or complex focusing mechanisms.
2Measurement precision
If a mechanical auto-focus mechanism is used, then measurement precision is improved, but response time is limited and productivity decreases
Solution Approach 1:
The patent replaces the slow mechanical auto-focus system with a pneumatic system that responds much faster to height variations. The pneumatic actuation through pressure and vacuum sources can rapidly adjust substrate positioning, enabling the system to meet high throughput demands while maintaining precise alignment.
3Ease of operation
If the substrate is placed on the chuck with assumptions about flatness and geometry, then ease of operation is improved, but manufacturing precision deteriorates due to inconsistencies
Solution Approach 1:
The patent introduces an air bearing as an intermediary between the substrate and the measurement system. This air bearing provides a stable, controllable reference plane that is not affected by chuck flatness variations or substrate geometry inconsistencies. The pneumatic system mediates the interaction, allowing simple substrate placement on the chuck while achieving high registration accuracy through the air bearing's stable reference surface.
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 provides accurate and non-contact registration of the substrate, enhancing precision and reducing the need for expensive auto-focus systems, enabling faster and more reliable substrate inspection and measurement processes.
Implementation Method 1
The air bearing has a pressure source and a vacuum source, where the vacuum source draws the substrate toward the air bearing
Implementation Method 2
the pressure source prevents the substrate from physically contacting the air bearing
Implementation Method 3
an air bearing disposed on the tool head adjacent the substrate. The air bearing has a pressure source and a vacuum source, where the vacuum source draws the substrate toward the air bearing and the pressure source prevents the substrate from physically contacting the air bearing
Data Source
AI summary
A tool for investigating a substrate, where the tool has a tool head for investigating the substrate, a chuck for disposing an upper surface of the substrate in proximity to the tool head, and an air bearing disposed on the tool head adjacent the substrate. The air bearing has a pressure source and a vacuum source, where the vacuum source draws the substrate toward the air bearing and the pressure source prevents the substrate from physically contacting the air bearing. The pressure source and the vacuum source work in cooperation to dispose the upper surface of the substrate at a known distance from the tool head. By using the air bearing as part of the tool in this manner, registration of the substrate to the tool head is accomplished relative to the upper surface of the substrate, not the back side of the substrate.