Faceplate hole density modulation for plasma uniformity
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Solution Overview
Problem
Semiconductor processing techniques face challenges in reducing particle generation while maintaining film thickness uniformity, as edge rings used to mitigate particle defects often lead to non-uniform film deposition due to altered plasma fields.
Innovation Solution
A faceplate with distinct regions of varying hole densities is employed in a semiconductor processing apparatus, where the inner region has a higher density of holes than the outer region, to modulate the plasma field and reduce the negative effects of edge rings on film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an edge ring is used to protect the substrate edge during deposition/etching processes, then particle generation due to bevel edge defects is reduced, but film thickness uniformity deteriorates due to altered plasma field near the substrate edge
Solution Approach 1:
The faceplate is divided into two regions with different hole densities: a first region (center) with higher hole density and a second region (perimeter) with lower hole density. This local differentiation allows the center region to maintain strong plasma generation for uniform film deposition, while the perimeter region reduces plasma modulation effects near the substrate edge, thereby maintaining film thickness uniformity without compromising particle protection from the edge ring.
Solution Approach 2:
The faceplate structure is segmented into distinct functional zones with varying hole densities. The first region (central area) has a higher density of holes to ensure adequate plasma generation, while the second region (outer perimeter area) has a lower density of holes to reduce plasma modulation effects. This segmentation enables each region to perform its specific function optimally, resolving the contradiction between particle protection and film uniformity.
2Device complexity
If the faceplate has uniform hole density across the entire surface, then plasma distribution is simplified, but film thickness uniformity deteriorates due to edge ring-induced plasma modulation
Solution Approach 1:
Instead of using a uniform hole density across the entire faceplate, the invention applies local quality by creating two distinct regions with different hole densities. The first region (center) has higher hole density while the second region (perimeter) has lower hole density. This local differentiation compensates for the edge ring-induced plasma modulation, ensuring uniform film thickness without requiring complex additional components.
3Manufacturing precision
If the hole density in the outer region is reduced to compensate for edge ring effects, then film thickness uniformity improves, but plasma generation in the outer region decreases
Solution Approach 1:
The faceplate is segmented into two regions with differentiated hole densities. The first region (center) maintains higher hole density to ensure adequate plasma generation, while the second region (outer perimeter) has reduced hole density to compensate for edge ring-induced plasma modulation. This segmentation allows each region to have optimized plasma generation characteristics appropriate to its location, achieving both uniform film thickness and sufficient overall plasma quantity.
Solution Approach 2:
The invention changes the physical parameter of hole density across different regions of the faceplate. By reducing the hole density in the outer perimeter region compared to the central region, the plasma generation is modulated to compensate for edge ring effects, achieving uniform film thickness while maintaining adequate overall plasma quantity through the higher-density central region.
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 faceplate design significantly improves film thickness uniformity by reducing plasma modulation effects at the substrate edge, resulting in a variation of 1.54% compared to 7.59% with constant hole density faceplates, effectively addressing the issue of edge ring-induced non-uniformities.
Implementation Method 1
The faceplate is configured with a first region having a first density of holes formed therethrough and a second region having a second density of holes formed therethrough. The second region may surround the first region and the second density of holes may be less than the first density of holes.
Data Source
AI summary
Embodiments described herein relate to a faceplate for improving film uniformity. A semiconductor processing apparatus includes a pedestal, an edge ring and a faceplate having distinct regions with differing hole densities. The faceplate has an inner region and an outer region which surrounds the inner region. The inner region has a greater density of holes formed therethrough when compared to the outer region. The inner region is sized to correspond with a substrate being processed while the outer region is sized to correspond with the edge ring.