Substrate Edge Protection Ring Assembly for Plasma Etching
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Solution Overview
Problem
During plasma processing in semiconductor manufacturing, the extreme edge of substrates is often etched undesirably, reducing the usable area for forming defect-free devices, as existing technologies fail to effectively protect this edge during etching processes.
Innovation Solution
A ring assembly comprising an edge ring and a shadow ring is used to protect the substrate edge, with the shadow ring being movable on pins to adjust its height and align concentrically with the edge ring, controlling the plasma sheath profile and preventing bevel attacks during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing is performed to etch patterns on substrate, then desired deposition or etch process is achieved, but extreme edge of substrate is etched undesirably resulting in less usable area
Solution Approach 1:
The protection system is divided into two separate rings: an edge ring that contacts the substrate edge and a shadow ring that shadows the plasma flow. This segmentation allows each component to perform its specific function - the edge ring provides direct mechanical protection while the shadow ring controls plasma flow direction, together preventing edge erosion without sacrificing substrate area
Solution Approach 2:
The ring assembly acts as an intermediary component between the plasma source and the substrate edge. By introducing this intermediate structure, the harmful plasma flow is redirected away from the substrate edge while maintaining the beneficial etching process on the main substrate area, thus resolving the contradiction between etching precision and usable area
2Productivity
If substrate layout utilizes area close to edge to maximize electronic devices, then substrate utilization is maximized, but plasma etches extreme edge undesirably during processing
Solution Approach 1:
The ring assembly is installed on the substrate support before the substrate is placed in the processing chamber. This preliminary action ensures that the protective structure is already in position to prevent edge erosion during the entire processing sequence, allowing maximum substrate utilization without risking edge damage during fabrication
3Manufacturing precision
If shadow ring is made movable on pins to adjust height, then plasma sheath profile control is improved, but device complexity increases
Solution Approach 1:
The shadow ring is designed with movable capability on pins, allowing it to adjust its height position dynamically. This dynamic feature enables precise control of the plasma sheath profile by adjusting the shadow ring's position relative to the substrate edge, optimizing protection effectiveness for different processing conditions while maintaining a relatively simple mechanical structure
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 solution maximizes the usable substrate area by precisely controlling the plasma sheath and etch profile at the extreme edge, reducing defects and enhancing processing efficiency.
Implementation Method 1
The electrostatic chuck has a support surface configured to support a substrate thereon
Implementation Method 2
supplying a process gas mixture to a vacuum chamber implying radiofrequency power to excite the process gas into a plasma state. The plasma decomposes the gas mixture into ion species that perform the desired deposition or etch process
Data Source
AI summary
Embodiments of the present disclosure provide a method and an apparatus for processing a substrate. The apparatus has a ring assembly. The ring assembly has an edge ring and a shadow ring. The edge ring has a ring shaped body. The edge ring body has a top surface and a bottom surface. Pin holes extend through the edge ring body from the top surface to the bottom surface. The shadow ring has a ring shaped body. The shadow ring body has an upper surface and a lower surface. Sockets are formed on the lower surface, wherein the sockets in the shadow ring body align with the pin holes in the edge ring body.