Removable Aperture Structures for Clamping Distorted Lithography Substrates
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Solution Overview
Problem
Lithographic substrates with increased height structures face challenges in reliable clamping due to distortion, leading to difficulties in pattern formation and increased overlay errors, as existing substrate holders struggle to accommodate varying substrate deformations and maintain accurate clamping forces.
Innovation Solution
A substrate holder with adjustable free height between the base surface and the substrate, featuring removable structures with apertures and adhesive layers, allows for localized control of clamping fluid flow and pressure drops, enabling better support of substrates with deformations such as umbrella shapes and improving clamping reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If substrates with significant height structures (3D-NAND) are formed, then functional elements per device increase, but substrate distortion increases causing clamping difficulties and overlay errors
Solution Approach 1:
The patent applies local quality by providing different free heights at different locations on the substrate holder. Specifically, the substrate holder has a first free height in a first region and a second free height in a second region, allowing localized adjustment to compensate for substrate distortion in specific areas while maintaining overall substrate flatness for accurate patterning
2Manufacturing precision
If clamping force is increased to flatten distorted substrates, then substrate flatness improves, but substrate holder wear increases during loading and unloading
Solution Approach 1:
The patent applies parameter changes by varying the free height parameter of the substrate holder in different regions. This allows the system to achieve adequate substrate flatness with reduced clamping force by having taller support structures in regions where substrate distortion occurs, thereby reducing mechanical stress and wear on the substrate holder during repeated loading and unloading cycles
3Device complexity
If uniform free height is used across the substrate holder, then device complexity is reduced, but adaptability to substrates with varying distortion is limited
Solution Approach 1:
The patent applies segmentation by dividing the substrate holder into multiple regions with different free heights. The substrate holder is segmented into a first region with a first free height and a second region with a second free height, enabling the system to adapt to substrates with varying distortion patterns while maintaining a relatively simple overall structure that can be manufactured and maintained
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 adjustable substrate holder enhances clamping strength and reduces overlay errors, effectively supporting substrates with deformations while maintaining accurate pattern formation and throughput.
Implementation Method 1
the structure comprises an adhesive layer on the substrate holder facing surface for adhering the structure to the base surface of the substrate holder
Implementation Method 2
there being a free height between the base surface of the substrate holder and a bottom surface of the substrate; wherein: the free height varies in different regions of the substrate holder
Data Source
AI summary
A structure for use on a base surface of a substrate holder, wherein the structure is substantially planar with a substrate holder facing surface that is both securable to the base surface of the substrate holder and also removable from the base surface of the substrate holder, the structure having a plurality of apertures therethrough that are arranged such that a plurality of burls on the base surface may pass through the respective apertures, wherein the diameter of the apertures is in the range 50 μm to 1000 μm and the pitch between adjacent apertures is in the range 1 mm to 3 mm.