Lift Pin Assembly With Polymer Tip For Substrate Handling
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Solution Overview
Problem
Conventional metal lift pins in substrate handling systems generate particles on the substrate due to impact, which can contaminate processing chambers, and maintaining a hard surface is necessary for supporting heavier and hotter shutter disks.
Innovation Solution
A lift pin assembly with an elongate metal base and a tip made of an electrically conductive polymer, where the tip's opposing side has a feature to mate with the base, allowing for removability and reducing particle generation by preventing substrate contact with the metal base.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal lift pins are used to provide rigidity and support, then structural strength is improved, but particle generation on the substrate increases
Solution Approach 1:
The lift pin is divided into two distinct segments: a metal base portion that provides structural strength and rigidity, and a polymer tip portion that contacts the substrate. This segmentation allows each part to perform its optimal function - the metal base maintains structural integrity while the polymer tip prevents particle generation during substrate contact.
Solution Approach 2:
Different materials are applied to different parts of the lift pin structure. The base portion uses metal material for strength and rigidity, while the tip portion uses polymer material for low particle generation. This local quality differentiation resolves the contradiction by optimizing material properties at each specific location where they are most needed.
2Force
If a hard surface is used to support the shutter disk, then load-bearing capacity is improved, but particle generation risk increases
Solution Approach 1:
The support structure is segmented into a metal base for bearing the heavy shutter disk load and a polymer tip for actual contact with the substrate or disk. This segmentation enables the hard metal surface to provide load-bearing capacity while the softer polymer surface minimizes particle generation during contact operations.
Solution Approach 2:
The polymer tip acts as an intermediary between the metal base and the substrate/shutter disk. It transfers the load from the substrate to the metal base while providing a soft contact surface that prevents particle generation, thus mediating between the conflicting requirements of hard support and soft contact.
3Object-generated harmful factors
If a polymer tip is used to reduce particle generation, then substrate cleanliness is improved, but thermal conductivity decreases
Solution Approach 1:
The thermal management function is segmented from the contact function. The polymer tip handles substrate contact and cleanliness while the metal base handles thermal conduction and heat dissipation. This segmentation allows the polymer to provide low particle generation benefits while the metal ensures adequate thermal conductivity through the lift pin structure.
Solution Approach 2:
The polymer tip serves as a thermal intermediary, allowing heat transfer from the substrate to the metal base through conduction across the polymer-metal interface. While polymer has lower thermal conductivity than metal, the segmentation ensures that the metal base provides the primary thermal pathway, balancing contact quality with thermal management.
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 solution effectively decreases particle generation on the substrate's backside while enabling support for heavier and hotter shutter disks, and can be easily retrofitted into existing systems without costly modifications.
Implementation Method 1
The inventors have observed that impact between the substrate and metal surfaces results in particle generation on the substrate and in the processing chambers
Implementation Method 2
Lift pins extend through a substrate support to lift a substrate off the substrate support to facilitate placement and removal of the substrate onto the substrate support. Conventionally, lift pins are formed of a metal to improve rigidity
Implementation Method 3
a tip formed of a second material different than the first material and having a support surface on a first side of the tip and an opposing second side of the tip, wherein the opposing second side includes a second feature to mate with the first feature of the base to removably retain the tip on the distal end of the base
Data Source
AI summary
Embodiments of lift pin assemblies are provided herein. In some embodiments, a lift pin assembly includes an elongate base formed of a first material and having a first feature formed in a distal end of the base to interface with and removably support a tip; and a tip formed of a second material different than the first material and having a support surface on a first side of the tip and an opposing second side of the tip, wherein the opposing second side includes a second feature to mate with the first feature of the base to removably retain the tip on the distal end of the base.