Lithographic Substrate Table Adapter for Non-Standard Wafer Alignment
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Solution Overview
Problem
Lithographic apparatuses face challenges in handling non-standard substrates of varying sizes and shapes, leading to alignment issues and contamination due to the limitations of standard substrate holders and etched recesses.
Innovation Solution
A substrate table with a polished surface supports a second substrate of a non-standard type, using a recess and holder configuration that ensures accurate alignment and minimizes contamination, allowing for the projection of a patterned radiation beam onto the non-standard substrate without requiring major modifications to the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a standard substrate holder is used to hold non-standard substrates, then the apparatus can maintain its original design, but alignment accuracy deteriorates due to size and shape mismatches
Solution Approach 1:
The substrate holder is segmented into a standard base portion and a removable adapter portion. The adapter is specifically designed to match non-standard substrate sizes and shapes, allowing the standard apparatus to accommodate varied substrates while maintaining alignment accuracy through the customized adapter interface.
Solution Approach 2:
An adapter serves as an intermediary component between the standard substrate holder and non-standard substrates. This adapter translates the standard holder's interface to match the unique geometry of non-standard substrates, enabling accurate alignment without modifying the original apparatus design.
2Adaptability or versatility
If an etched recess is used to hold non-standard substrates, then substrate support is provided, but manufacturing precision deteriorates due to etching process tolerances
Solution Approach 1:
Instead of creating precise, permanent etched recesses in expensive substrate tables, the invention uses disposable or replaceable adapter components that can be manufactured with standard tolerances. These adapters are simpler to manufacture and can be replaced if damaged, avoiding the need for high-precision etching processes.
Solution Approach 2:
The support function is extracted from the substrate table itself and transferred to removable adapter components. This allows the substrate table to remain simple and unmodified, while the adapters provide the necessary support geometry without requiring high-precision etching into the table.
3Ease of operation
If non-standard substrates are placed in etched recesses, then substrate handling is enabled, but contamination increases due to chip formation from repeated placement
Solution Approach 1:
The adapter components are designed to be replaceable and can be discarded or renewed when damaged. This prevents chip formation from accumulating in permanent recesses, as damaged adapters are simply replaced rather than reused, significantly reducing contamination risks.
Solution Approach 2:
The substrate holding function is extracted from the permanent substrate table structure and placed in removable adapters. This allows damaged adapters to be easily removed and replaced, preventing chip accumulation and contamination that would occur with permanent etched recesses.
4Measurement precision
If custom substrate tables are designed for non-standard substrates, then handling precision improves, but device complexity and cost increase
Solution Approach 1:
The substrate handling system is segmented into a standard base table and interchangeable adapters. Each adapter is designed for specific non-standard substrate types, providing precision alignment for those substrates without requiring custom modification of the main table. This modular approach maintains simplicity while enabling precision.
Solution Approach 2:
The standard substrate table is designed with universal compatibility through the adapter interface. A single table design can handle multiple substrate types by simply changing the adapter, avoiding the need for multiple custom tables while maintaining alignment precision for each substrate type.
Data Source
AI summary
A lithographic apparatus includes a substrate table constructed to hold a first substrate of a first type, the first substrate having a polished surface; and a projection system configured to project a patterned radiation beam onto a target portion of a substrate. The polished surface supports a second substrate of a second type and the projection system is configured to project the patterned radiation beam onto the second substrate.