Stepped Holding Stage for Uniform Wafer Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma processing apparatuses struggle to effectively deposit thin films on the peripheral portions of semiconductor wafers, particularly the rear surfaces, due to inadequate exposure to processing gases, and face challenges in etching or ashing these areas.
Innovation Solution
A holding stage structure with a stepped portion and guide pin mechanism is introduced, allowing the peripheral portion of the rear surface of the wafer to be exposed to processing gases, and incorporating an electrostatic chuck and elevation pins to secure and position the wafer, ensuring even film deposition and preventing lateral sliding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional holding stage structure is used, then the wafer can be held and processed, but the peripheral portions of the rear surface cannot be effectively exposed to processing gases for thin film deposition
Solution Approach 1:
The patent introduces a stepped portion that creates a height difference (first height and second height) on the holding stage, enabling the peripheral portions of the rear surface to be exposed to processing gases. This dimensional change allows plasma to reach areas that were previously inaccessible, achieving uniform thin film deposition on the entire wafer surface including edge and rear surface peripheral portions.
Solution Approach 2:
The holding stage is divided into multiple levels with different heights. The first holding area is positioned at a first height while the second holding area is positioned at a second height, creating segmented zones that facilitate differential exposure to processing gases. This segmentation enables the peripheral portions of the rear surface to receive plasma treatment independently from the central areas.
2Reliability
If the wafer is placed on a flat holding stage, then the structure is simple, but the wafer may laterally slide or be displaced during processing
Solution Approach 1:
The patent incorporates guide pins positioned at specific locations on the holding stage to prevent lateral sliding of the wafer. These guide pins are strategically placed to provide mechanical guidance without interfering with the stepped portion's function of exposing peripheral portions to processing gases. The local addition of guide pins enhances position stability while maintaining the overall simplicity of the holding stage design.
3Productivity
If the peripheral portions of the rear surface are exposed to processing gases, then thin film deposition can be achieved, but the holding stage structure becomes more complex
Solution Approach 1:
By creating a stepped structure with different heights, the patent enables the peripheral portions of the rear surface to be exposed to processing gases in a controlled manner. This dimensional modification allows plasma to reach previously inaccessible areas, achieving uniform thin film deposition across the entire wafer surface including edge and rear surface peripheral portions, thereby improving processing efficiency.
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 configuration enables uniform thin film deposition on both the edge and rear surface peripheral portions of the wafer, improving processing efficiency and preventing wafer displacement during plasma processing.
Implementation Method 1
an electrostatic chuck 14 for holding the wafer W using an electrostatic force is formed near the top surface of the holding stage body 10
Implementation Method 2
Plasma is generated in a processing space S of the process chamber 4 due to the microwaves
Implementation Method 3
microwaves of, for example, 2.45 GHz generated by a microwave generator 28 are converted into a vibration mode by a mode converter 30
Data Source
AI summary
Provided is a holding stage structure which holds a substrate and disposed in a process chamber that is vacuum-evacuatable and allows a predetermined process to be performed on the substrate therein. The holding stage structure includes: a holding stage body on which the substrate is placed; an elevation pin mechanism lowering the substrate on the holding stage body or raising the substrate from the holding stage body; and a stepped portion formed on the holding stage body so that a peripheral portion of a rear surface of the substrate placed on the holding stage body is exposed to a processing gas supplied into the process chamber.