RF Return Grounding Structure for Uniform PECVD Thin Films
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Solution Overview
Problem
In plasma enhanced chemical vapor deposition (PECVD) processes, non-uniform plasma density and particle generation due to inadequate RF return schemes lead to decreased yield and equipment durability issues in manufacturing OLED devices.
Innovation Solution
A radio frequency (RF) return device with a bracket, cover, and contact plate is mounted on the chamber body, providing a grounding path between the substrate support and the chamber, while shielding components from high temperatures and aggressive chemicals, thus enhancing durability and reducing particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the susceptor is connected to the chamber body providing a RF current return path, then the PECVD process can be performed, but non-uniform plasma density and particle generation occur leading to decreased yield
Solution Approach 1:
The RF return path is segmented into multiple separate return paths instead of a single path through the susceptor. This includes a first RF return path and a second RF return path that are electrically connected to the chamber body, distributing the RF current more uniformly across the chamber to improve plasma density uniformity and reduce particle generation.
Solution Approach 2:
A grounding device with a contact plate is introduced as an intermediary component to establish a new RF current return path between the chamber body and ground. This intermediary structure provides an alternative path for RF current that bypasses the susceptor, reducing its role as the sole return path and improving overall current distribution uniformity.
2Manufacturing precision
If equipment is added to process chambers to improve RF return, then RF current distribution may improve, but particle generation inside process chambers increases
Solution Approach 1:
The RF return function is extracted from the susceptor and transferred to separate grounding devices with contact plates. By removing the RF return responsibility from the susceptor, the invention eliminates the source of particle generation associated with susceptor-based RF returns while maintaining the necessary RF current distribution for plasma uniformity.
Solution Approach 2:
The contact plates are designed as replaceable, simple components that can be easily replaced if particles are generated. This approach uses simple, low-cost components that prioritize process improvement over long-term durability, allowing quick replacement rather than complex maintenance of particle-free components.
3Reliability
If the contact plate is exposed to high temperatures and aggressive chemicals in the processing volume, then it can provide RF return, but equipment durability decreases
Solution Approach 1:
The contact plate is extracted from the processing volume environment and positioned outside it to provide RF return. By removing the contact plate from direct exposure to high temperatures and aggressive chemicals inside the processing volume, the invention maintains RF return functionality while significantly improving component durability and reducing maintenance requirements.
Solution Approach 2:
The contact plate serves as an intermediary that establishes electrical connection between the chamber body and ground without needing to withstand harsh processing conditions. It mediates the RF return function while remaining in a more favorable environmental position, protecting the overall system durability.
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 RF return device improves RF current distribution, increases equipment durability, and reduces particle contamination, leading to more uniform thin film deposition and increased process yield.
Implementation Method 1
a spring, where the cover is configured to shelter the spring from a processing volume of the chamber body, and where the spring is configured to move the contact plate and the bottom cover upwards to a first position when an upward pressure on the contact plate is applied
Implementation Method 2
The RF return device generally includes a bracket for coupling to a chamber body, a cover coupled to the bracket, and a contact plate coupled to the cover and configured to contact a substrate support
Data Source
AI summary
Embodiments of the present disclosure provide a radio frequency (RF) return device. One example RF return device generally includes a bracket for coupling to a chamber body, a cover coupled to the bracket, and a contact plate coupled to the cover and configured contact a substrate support. Using the RF return device described herein generally enables a reduction in temperature that the RF return device and its various components are exposed to, increasing the durability and lifetime of the RF return device. In addition, the RF return device disclosed herein may block chemicals (e.g., fluorine (F)) used in the process chamber from attacking components included in the RF return device, thereby providing enhanced protection to the RF return device.