Dual Clamping System for Lithography Substrate Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithographic apparatuses face challenges in achieving precise patterning due to substrate warping and thermal stress induced during clamping, leading to substrate distortion and overlay errors during the lithography process.
Innovation Solution
A dual clamping system is implemented, where the substrate table is first clamped to the support structure, and then the substrate is clamped to the table, allowing for independent vacuum or electrostatic clamping to minimize stress and contamination effects, and enabling thermal equilibrium before substrate loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the substrate is clamped directly to the substrate table support structure, then clamping force is sufficient, but substrate warping and thermal stress occur leading to distortion
Solution Approach 1:
The clamping system is segmented into two independent stages: first clamping the substrate table to the support structure, then clamping the substrate to the table. This segmentation allows each clamping action to be optimized independently, preventing direct transmission of excessive clamping force to the substrate while ensuring adequate holding force at each interface.
Solution Approach 2:
The substrate table is clamped to the support structure before the substrate is loaded and clamped to the table. This preliminary action allows the table to reach thermal equilibrium and establish a stable base, preventing thermal stress from being transmitted to the substrate during the clamping process.
2Productivity
If both substrate table and substrate are clamped simultaneously, then processing time is reduced, but thermal stress and contamination effects increase
Solution Approach 1:
The substrate table is clamped to the support structure before the substrate is loaded. This preliminary clamping action allows the table to reach thermal equilibrium and prepare the clamping interface, reducing thermal stress on the substrate when it is subsequently clamped. The sequence is: clamp table to support, then load and clamp substrate to table.
3Ease of operation
If the substrate table is not clamped before substrate loading, then substrate loading is faster, but overlay accuracy decreases due to thermal-induced stress
Solution Approach 1:
The substrate table is clamped to the support structure in advance before substrate loading occurs. This preliminary action allows the table to reach thermal equilibrium and establish a stable, stress-free base. When the substrate is subsequently loaded and clamped, the table is already thermally stabilized, preventing thermal-induced stress from affecting overlay accuracy during the loading process.
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 approach enhances precision in pattern transfer by reducing substrate distortion and thermal-induced stress, improving overlay accuracy and reducing contamination sensitivity.
Implementation Method 1
allowing for independent vacuum or electrostatic clamping
Implementation Method 2
allowing for independent vacuum or electrostatic clamping
Implementation Method 3
allowing for independent vacuum or electrostatic clamping
Implementation Method 4
allowing for independent vacuum or electrostatic clamping
Implementation Method 5
enabling thermal equilibrium before substrate loading
Data Source
AI summary
A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate is disclosed, the apparatus including a substrate table constructed to hold a substrate, a first clamping system configured to clamp the substrate table to a substrate table support structure, and a second clamping system configured to clamp a substrate to the substrate table after the substrate table has been clamped to the substrate table support structure.