Perforated Lithography Gripper for Residual Liquid Extraction
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Solution Overview
Problem
Residual liquid on substrates in lithographic apparatuses is transferred to grippers, which then inadvertently transfer it to other substrates, leading to reduced yield due to unwanted liquid transfer during substrate handling.
Innovation Solution
A gripper design with a main body featuring openings perpendicular to the substrate surface and a suction module with a fluid extraction conduit to minimize liquid retention and prevent transfer, utilizing a ribbed structure and suction module to extract residual liquid from the gripper surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gripper design is used to transport substrates, then substrate handling is achieved, but residual liquid is transferred from one substrate to another through the gripper
Solution Approach 1:
The gripper body is segmented with a plurality of openings that divide the solid structure into multiple sections, allowing liquid to pass through rather than accumulate on the gripper surface
Solution Approach 2:
The gripper incorporates a porous or perforated structure with openings distributed across its surface, enabling it to function as a filter that allows liquid penetration while maintaining structural integrity for substrate handling
2Stability of the object's composition
If the gripper surface area in contact with substrate is increased for better gripping, then gripping stability is improved, but liquid retention on gripper surface increases
Solution Approach 1:
The gripper surface is segmented into multiple opening sections that maintain contact area for stable gripping while allowing liquid to pass through the openings rather than being retained on the surface
Solution Approach 2:
The gripper employs a porous structure with distributed openings that provides sufficient surface area for stable substrate contact while enabling liquid permeation to minimize retention
3Manufacturing precision
If immersion lithography is used to improve resolution of smaller features, then imaging precision is improved, but residual liquid remains on substrate surface after processing
Solution Approach 1:
The suction module extracts residual liquid from the substrate surface and removes it from the system through the extraction conduit connected to a vacuum source
Solution Approach 2:
The suction module utilizes pneumatic principles with a vacuum source created by a pump to generate negative pressure that draws liquid off the substrate surface through the suction head
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 gripper effectively reduces the amount of liquid retained on its surface, preventing liquid transfer to other substrates and maintaining substrate cleanliness, thereby enhancing yield by minimizing residual liquid impact on thermal properties.
Implementation Method 1
a suction module (1503) arranged to suction liquid from surfaces of the gripper (1301). The suction module (1503) comprises a fluid extraction conduit (1505) in fluid communication with a vacuum source (1506) created by a pump (1507)
Data Source
AI summary
A gripper configured to transport a substrate in a lithographic apparatus, the gripper including: a main body with one or more engagement portions for engaging with a surface of the substrate, wherein a part of the main body, that is overlapped by a region of a substrate when the one or more engagement portions are engaged with the substrate, has a plurality of openings that extend through the main body in a direction substantially perpendicular to the surface of the substrate.