Thin-Film Substrate Holder for EUV Clamping and Temperature Control
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Solution Overview
Problem
In high-throughput lithographic apparatuses, conventional substrate holders face challenges in securely clamping substrates due to high accelerations, especially in extreme ultraviolet (EUV) radiation lithography where vacuum clamping is not feasible, and temperature control is critical to prevent thermal stress and overlay errors.
Innovation Solution
A substrate holder with a thin-film stack forming electronic or electric components, including electrostatic clamps and temperature sensors/heaters, is integrated into the lithographic apparatus, featuring a main body with burls that project from the surface to support the substrate and provide secure clamping and precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum clamping is used to secure substrates, then clamping reliability is improved, but it cannot be applied in EUV lithography where vacuum conditions are not feasible
Solution Approach 1:
The patent replaces the vacuum-based clamping mechanism with an electrostatic clamping system. The substrate holder includes a clamping element that generates electrostatic forces to secure the substrate, eliminating the need for vacuum conditions. This substitution allows the same clamping function to be achieved through electromagnetic fields rather than mechanical vacuum pressure, enabling use in EUV lithography environments where vacuum is not feasible.
2Manufacturing precision
If conventional substrate holders are used, then device simplicity is maintained, but temperature control precision is insufficient to prevent thermal stress and overlay errors
Solution Approach 1:
The patent merges multiple functions into the substrate holder structure. The holder integrates support functions (holding the substrate), clamping functions (securing the substrate through electrostatic forces), and temperature control functions (heating and cooling elements). This consolidation of multiple subsystems into a single integrated component achieves precise temperature control while managing the complexity through functional integration rather than separate independent systems.
Solution Approach 2:
The patent implements active temperature control by changing the thermal parameters of the substrate holder. Heating elements and cooling elements are integrated into the holder structure, allowing dynamic adjustment of temperature to maintain optimal conditions during lithography processes. This active parameter control prevents thermal stress and overlay errors by compensating for temperature variations in real-time.
3Productivity
If high-throughput lithographic apparatuses operate with high accelerations, then productivity is improved, but substrate clamping security deteriorates
Solution Approach 1:
The patent replaces mechanical clamping systems with electrostatic clamping to overcome the limitations imposed by high acceleration forces. Electrostatic forces can be dynamically adjusted and maintained without the mechanical wear and structural limitations that would prevent secure clamping during high-speed operations. This enables the substrate to remain securely held even during the high acceleration phases of high-throughput lithography.
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
The substrate holder effectively secures the substrate with electrostatic clamping and maintains accurate temperature control, reducing thermal stress and overlay errors, even in environments where vacuum clamping is not possible.
Implementation Method 1
electrostatic clamps... provide secure clamping
Implementation Method 2
temperature sensors/heaters... precise temperature control
Implementation Method 3
heaters... maintain accurate temperature control
Data Source
AI summary
A substrate holder for a lithographic apparatus has a main body having a thin-film stack provided on a surface thereof. The thin-film stack forms an electronic or electric component such as an electrode, a sensor, a heater, a transistor or a logic device, and has a top isolation layer. A plurality of burls to support a substrate are formed on the thin-film stack or in apertures of the thin-film stack.