PECVD Diffuser Plate Edge Rounding
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Solution Overview
Problem
The increasing size of diffuser plates in PECVD systems for large area substrates leads to more gas distribution holes and a contoured downstream side, resulting in flaking of deposited materials and increased particle formation, which reduces yield and uniformity in the deposition process.
Innovation Solution
A method involving the use of a compliant abrasive member to round the sharp edges of holes and contoured corners on the downstream surface of the diffuser plate, forming a radius at the edges to reduce material flaking and particle formation, utilizing CNC machines for precise and uniform coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the diffuser plate size is increased to accommodate large area substrates, then the deposition area is improved, but the number of gas distribution holes and contoured features increases leading to more sharp corners that cause flaking and particle formation
Solution Approach 1:
The patent applies preliminary action by rounding the sharp corners of gas distribution holes and contoured features on the diffuser plate before the deposition process begins. This pre-treatment eliminates the root cause of flaking and particle formation, allowing the large diffuser plate to operate without generating harmful particles during the deposition process.
Solution Approach 2:
The patent applies spheroidality by replacing sharp corners with rounded edges having a specified radius of curvature. This curvature modification eliminates stress concentration points that cause flaking, thereby reducing particle formation while maintaining the large diffuser plate area needed for processing large substrates.
2Manufacturing precision
If more gas distribution holes and contoured features are added to enhance plasma uniformity, then the deposition uniformity is improved, but the complexity of manufacturing and the number of sharp corners increase leading to more flaking
Solution Approach 1:
The patent applies local quality by selectively rounding only the corners of gas distribution holes and contoured features while leaving the rest of the diffuser plate features intact. This localized modification addresses the flaking problem at specific critical locations without requiring a complete redesign or simplification of the overall complex diffuser plate structure needed for uniform deposition.
3Object-generated harmful factors
If sharp corners are removed from the diffuser plate, then particle formation is reduced, but additional manufacturing steps are required increasing process complexity
Solution Approach 1:
The patent applies mechanics substitution by replacing traditional mechanical corner removal methods (such as machining or grinding) with a chemical etching process. This substitution simplifies the manufacturing process by using chemical reactions to selectively remove material at sharp corners, achieving the desired rounding effect with fewer and simpler manufacturing steps compared to mechanical alternatives.
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 method effectively reduces the flaking of deposited materials and undesirable particles during the PECVD process, enhancing the uniformity and yield of the substrate deposition by minimizing film stress on the diffuser plate.
Implementation Method 1
removing material with an abrasive member from a non-planar downstream surface of a diffuser plate to form a surface with a radius at an edge of each of a plurality of holes
Data Source
AI summary
Methods for manufacturing a diffuser plate for a PECVD chamber are provided. The methods provide for applying a compliant abrasive medium to round the sharp edges at corners of the output holes on a contoured downstream side of a gas diffuser plate. By rounding the edges of the output holes reduces the flaking of deposited materials on the downstream side of the gas diffuser plate and reduces the amount of undesirable particles generated during the PECVD deposition process.