Substrate Support Pumping in Stacked Process Chambers
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Solution Overview
Problem
Semiconductor manufacturing processes with vertically stacked load lock chambers face challenges in providing uniform pumping due to limited physical space, particularly affecting the upper chamber where access is restricted by pump ports and other components.
Innovation Solution
A substrate support system is designed for chambers with limited space, featuring a ledge that separates the chamber into processing and pumping volumes, a pump port, utilities feed, and a cover plate that allows for efficient installation and alignment, ensuring uniform gas flow around the substrate by creating a gap between the substrate support and the ledge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If vertically stacked load lock chambers are used to save space, then chamber density is improved, but uniform pumping around the substrate is worsened due to limited vertical space for configuring pump ports and chamber components
Solution Approach 1:
The patent transitions from vertical stacking to horizontal arrangement of pump ports around the substrate support. Instead of pumping from above/below in a vertical configuration, multiple pump ports are positioned circumferentially at the same horizontal level, creating uniform pumping paths in the radial dimension while maintaining compact vertical footprint.
Solution Approach 2:
The pumping function is segmented into multiple independent pump ports distributed around the substrate support. This segmentation allows each port to contribute equally to substrate pumping, ensuring uniform gas flow removal from all areas of the substrate surface, which resolves the non-uniform pumping issue in stacked configurations.
2Manufacturing precision
If pump ports are reconfigured for uniform pumping in stacked chambers, then pumping uniformity is improved, but chamber design complexity increases due to additional components like ledges and notches
Solution Approach 1:
The ledge structure serves multiple functions: it provides mechanical support for the substrate support, creates the necessary spacing for uniform gas flow, and forms the central opening for pump port access. This multi-functionality reduces the need for additional separate components, managing design complexity while achieving pumping uniformity.
Solution Approach 2:
The pump port structure is merged with the chamber floor and ledge assembly. The pump port passes through the floor and is integrated with the ledge's central opening, combining multiple structural elements into a unified design that simplifies manufacturing while maintaining the required geometric precision for uniform pumping.
3Manufacturing precision
If substrate support is positioned away from the ledge to create pumping gaps, then gas flow uniformity is improved, but vertical space utilization is worsened in already constrained stacked chambers
Solution Approach 1:
The patent compensates for reduced vertical spacing by utilizing horizontal/radial spacing between the substrate support and ledge. The substrate support is positioned radially inward from the ledge, creating annular pumping gaps in the horizontal plane rather than relying on vertical clearance, thus maintaining gas flow uniformity without requiring additional vertical space.
Solution Approach 2:
The gap between the substrate support and ledge is optimized locally to ensure sufficient spacing for uniform gas flow in the radial direction. This localized quality control at the substrate-ledge interface achieves the required pumping uniformity while adapting to the constrained overall chamber volume in stacked configurations.
Data Source
AI summary
Substrate supports for use in process chambers having limited physical space for configuring chamber components are disclosed. In some embodiments, a substrate support may include a body having a support surface; a utilities feed coupled to the body and comprising a second portion coupled to and extending laterally away from the body beyond a diameter of the body, and first portion coupled to the second portion and extending perpendicularly away from the body; and a cover plate movably disposable beneath and with respect to the body between a first position disposed completely beneath the body, and a second position wherein the cover plate is disposed over the first portion of the utilities feed and includes a first portion disposed beneath the body, and wherein the first portion has a curved edge having a radius equal to the distance from a central axis of the support surface to the curved edge.