Non-Axisymmetric Gas Diffuser Structure for PECVD Uniformity
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Solution Overview
Problem
Conventional symmetrical gas deflectors in plasma enhanced chemical vapor deposition (PECVD) systems suffer from limited uniformity and run-to-run consistency due to plate deformation, leading to inconsistent gas flow distribution and non-uniform film thickness deposition.
Innovation Solution
A non-symmetrical gas diffuser support structure with a backing plate and a gas deflector of unequal length and width, coupled by fasteners and spacers, which maintains a length-to-width ratio of 0.1:1 to 10:1, providing enhanced uniformity by compensating for asymmetries in the processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If symmetrical gas deflectors are used, then the structure is simple and easy to manufacture, but the gas flow distribution uniformity and run-to-run consistency are poor
Solution Approach 1:
The patent applies asymmetry by designing a gas deflector with non-equal dimensions in different directions. The deflector has a first dimension and a second dimension that are not equal, creating an asymmetric geometry that compensates for chamber asymmetries. This asymmetric design improves gas flow distribution uniformity and run-to-run consistency while maintaining manufacturing feasibility through standard fabrication processes.
2Device complexity
If conventional gas deflectors are used, then the device complexity is low, but plate deformation occurs leading to inconsistent gas flow distribution
Solution Approach 1:
The patent applies segmentation by dividing the gas deflector into multiple sections or zones with different geometric characteristics. The deflector is segmented such that different portions have different dimensions or orientations, allowing each segment to address specific flow distribution needs. This segmentation prevents plate deformation issues while maintaining reasonable device complexity.
Solution Approach 2:
The asymmetric geometry of the gas deflector, with unequal first and second dimensions, addresses plate deformation by distributing mechanical stresses more evenly across the structure. The asymmetric design prevents warping that would otherwise occur in symmetrical deflectors, thereby improving run-to-run consistency without significantly increasing device complexity.
3Device complexity
If symmetrical gas deflectors are used, then the structure is simple, but uniform film thickness deposition across the substrate is poor
Solution Approach 1:
The asymmetric gas deflector design, with unequal dimensions in different directions, is specifically configured to compensate for asymmetries in the processing chamber geometry. This asymmetric configuration ensures that gas flow is distributed more uniformly across the substrate surface, achieving better film thickness uniformity while maintaining relatively simple device structure.
Solution Approach 2:
The gas deflector incorporates local quality variations through its asymmetric geometry, where different regions of the deflector have different dimensions or orientations. This allows specific areas of the deflector to address local flow distribution needs, improving overall film thickness uniformity across the substrate while keeping the overall structure relatively simple.
Data Source
AI summary
The present disclosure generally provides an apparatus and method for gas diffuser support structure for a vacuum chamber. The gas diffuser support structure comprises a backing plate having a central bore, and a gas deflector having a length and a width unequal to the length coupled to the backing plate by a plurality of outward fasteners coupled to a plurality of outward threaded holes formed in the backing plate, in which a spacer is disposed between the backing plate and the gas deflector, and in which a length to width ratio of the gas deflector is about 0.1:1 to about 10:1.