Substrate Purge Structure for Dead Volume Defect Reduction
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Solution Overview
Problem
Substrate processing systems face defects due to dead volumes beneath the substrate, where particles accumulate and parasitic reactions occur, leading to non-uniformity and increased defects.
Innovation Solution
Incorporation of a purge structure with downwardly and radially outwardly directed holes to supply purge gas and a pumping structure with controlled flow paths to manage gas flow and reduce particle accumulation, along with heating elements to maintain temperature, effectively purging the dead volume beneath the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large chamber volume is used to isolate the reaction zone from grounded chamber walls, then parasitic coupling is reduced, but dead volumes accumulate particles and increase defects
Solution Approach 1:
The patent extracts the harmful dead volume beneath the substrate from the main chamber environment by introducing a dedicated purge structure that actively removes accumulated particles and reactive species from this isolated region, preventing their harmful effects while maintaining the large chamber volume benefits
Solution Approach 2:
The purge structure acts as an intermediary element between the reaction zone and the chamber bottom, using purge gas flow to mediate the removal of harmful particles and reactive species from the dead volume without requiring changes to the overall chamber design
2Object-generated harmful factors
If purge gas is supplied to the area beneath the substrate, then particle accumulation is reduced, but additional gas flow paths and structures are required
Solution Approach 1:
The substrate support structure is given multiple functions: it not only holds the substrate during processing but also incorporates integrated purge gas supply capabilities through holes in its bottom surface, eliminating the need for separate complex purge structures
Solution Approach 2:
The patent merges the purge gas distribution system with the substrate support structure by forming holes directly in the support, combining two previously separate functions into a single integrated component that reduces overall system complexity
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 reduces defects by managing conductance paths for reactive species, improving wafer uniformity and reducing parasitic oxide formation, thereby enhancing processing efficiency.
Implementation Method 1
The purge structure includes a first plurality of holes configured to supply purge gas to purge an area between the substrate support and the bottom surface of the processing chamber
Implementation Method 2
The pumping structure includes a second plurality of holes for controlling flow from the processing chamber through the pumping structure to the exhaust pumping ports
Implementation Method 3
a heater heats the purge structure to a predetermined temperature. A heater heats the pumping structure to a predetermined temperature
Data Source
AI summary
A substrate processing system includes a processing chamber including a top surface, a bottom surface and side walls. A substrate support is arranged in the processing chamber to support a substrate during processing. A purge structure is arranged in the processing chamber below a plane occupied by the substrate during processing. The purge structure includes a first plurality of holes configured to supply purge gas to purge an area between the substrate support and the bottom surface of the processing chamber.