Substrate Support Vacuum and Edge Purge Conduit Design
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Solution Overview
Problem
Current substrate supports for semiconductor processing face challenges in maintaining predictable and contaminant-free edge purge gas and vacuum flow due to inconsistent channel flow characteristics and fluid leaks, requiring complex and time-consuming manufacturing processes to establish reliable fluid-tight seals.
Innovation Solution
The substrate support design features a first plate with vertically and horizontally arranged passages, a coupled second plate, and an elongate shaft with internal vacuum and edge purge lines, forming fluid connections that enhance predictable vacuum and edge purge gas distribution, while a discontinuous coating on the rim minimizes contamination and facilitates easier manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If channels are formed within the substrate support plate to supply edge purge gas and vacuum, then fluid distribution to desired regions is achieved, but the channels are prone to inconsistent flow characteristics and fluid leaks
Solution Approach 1:
The substrate support plate is divided into multiple separate components (first plate, second plate, shaft) with channels formed in each. This segmentation allows for better control of fluid flow paths and reduces the likelihood of leaks by distributing the sealing requirements across multiple interfaces rather than relying on a single complex channel structure.
Solution Approach 2:
Channels are pre-formed in the plates and shaft before assembly. The first plate has vacuum passages and vertical passages formed in advance, and the shaft has internal vacuum and edge purge lines pre-configured. This preliminary formation ensures consistent flow characteristics are built into the structure before operation, reducing variability during actual use.
2Reliability
If complex manufacturing operations are used to create channels in support plates, then adequate and predictable edge purge gas and vacuum supply is achieved, but manufacturing time and complexity increase
Solution Approach 1:
The manufacturing process is segmented into forming channels in separate components (first plate, second plate, shaft) that can be independently fabricated using simpler operations. This avoids the need for complex through-channel machining in a single monolithic plate, reducing manufacturing time while maintaining reliable fluid supply through the distributed channel network.
Solution Approach 2:
The shaft is positioned within the plate assembly, with its internal lines nested alongside the plates. This nesting allows the shaft's pre-formed lines to integrate with the plates' channels, achieving adequate purge gas and vacuum supply without requiring complex interconnected channel carving in a single component.
3Reliability
If fluid-tight seals are established between the plate and shaft, then repeatable processes are maintained, but the seals are difficult to establish and maintain integrity
Solution Approach 1:
The seal interface is segmented into multiple locations: between the first plate and second plate, and between the shaft and the plates. This segmentation distributes the sealing requirements, making each individual seal easier to establish and maintain than a single complex seal would require. The discontinuous coating on the rim further divides the sealing surface into discrete contact points.
Solution Approach 2:
A discontinuous coating is applied to the rim of the plate, creating a flexible sealing interface. This thin film coating can accommodate minor surface irregularities and thermal expansion differences between components, maintaining seal integrity more easily than rigid metal-to-metal contacts while ensuring fluid-tight connections for process repeatability.
4Object-affected harmful factors
If edge purge gas is supplied through channels in the substrate support, then backside deposition is prevented, but contamination from channel materials may occur
Solution Approach 1:
The edge purge gas supply function is extracted from the plate material itself and implemented through separate shaft components with internal lines. This separation removes the potential contamination source (plate materials) from the edge purge gas path, allowing the gas to flow through the shaft's internal lines without contact with plate materials that could outgas or contaminate the process.
Solution Approach 2:
The shaft acts as an intermediary component between the gas source and the substrate edge. The shaft's internal lines serve as a mediator that delivers edge purge gas without direct contact between the gas and plate materials, preventing contamination while still achieving the desired prevention of backside deposition through proper gas distribution at the substrate edge.
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
This design improves the ease of manufacturing, maintains fluid-tight conditions, and ensures consistent and contaminant-free edge purge gas and vacuum supply, enhancing the reliability and repeatability of semiconductor processing operations.
Implementation Method 1
A vacuum is often used to hold the substrate down to the substrate support
Implementation Method 2
with the vacuum sometimes assisting in sealing the substrate against the raised portion of the support plate
Data Source
AI summary
Substrate supports are provided herein, In some embodiments, a substrate support includes a first plate; a plurality of vacuum passages disposed through the first plate; a plurality of vertical passages formed partially into the first plate; a plurality of horizontal passages disposed in the first plate, each of the plurality of horizontal passages beginning proximate a perimeter of the first plate and terminating proximate one of the plurality of vertical passages such that the horizontal passages and the vertical passages are in fluid communication; a second plate coupled to the first plate at an interface; an elongate shaft having a vacuum line and an edge purge line internal to the shaft; a vacuum channel formed at the interface fluidly coupling the vacuum line to the plurality of vacuum passages; and an edge purge channel formed at the interface fluidly coupling the edge purge line to the plurality of vertical passages.