Detachable Chuck Surface Handling for Stable Plasma Etching
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Solution Overview
Problem
The thermal expansion mismatch between the electrostatic chuck and wafer, as well as the change in shape of the focus ring during plasma etching, leads to inconsistent etching characteristics, making precise management and replacement of these components challenging, thereby affecting the productivity of plasma etching apparatus.
Innovation Solution
A substrate processing apparatus with a transportation chamber in an atmospheric environment, a vacuum processing chamber connected via a load lock chamber, and a detachable surface part for the substrate placing table, allowing for precise management and replacement of the electrostatic chuck and focus ring without opening the vacuum processing chamber to the atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrostatic chuck and focus ring are used continuously in plasma etching, then productivity is improved, but the etching characteristic deteriorates due to thermal expansion mismatch and shape change
Solution Approach 1:
The placing table is divided into a body part (maintained in vacuum chamber) and a surface part (detachable component containing electrostatic chuck and focus ring). This segmentation allows the surface part to be replaced independently without opening the vacuum chamber, enabling continuous productivity while maintaining etching characteristic consistency through periodic replacement of worn components.
Solution Approach 2:
The surface part is designed to be detachable and replaceable, transforming from a static permanent component to a dynamic interchangeable component. This allows the system to adapt by replacing worn surface parts with new ones, maintaining consistent etching characteristics over time while preserving overall system productivity.
2Reliability
If the vacuum processing chamber is opened to atmosphere to replace electrostatic chuck and focus ring, then etching characteristic consistency is improved, but productivity deteriorates due to chamber opening time
Solution Approach 1:
By segmenting the placing table into body part and surface part, the replacement operation is isolated to only the surface part. This allows replacement to be performed through a smaller opening or even through existing access points, significantly reducing the time the vacuum chamber must be opened and thus minimizing productivity loss while ensuring etching characteristic consistency.
Solution Approach 2:
The surface part containing the wear-prone components (electrostatic chuck and focus ring) is extracted as a separate replaceable unit. This extraction allows these components to be replaced independently without affecting the main vacuum chamber environment, enabling quick replacements that maintain etching consistency while preserving productivity.
3Productivity
If cleaning is performed without dummy wafer to save time, then productivity is improved, but etching characteristic deteriorates due to chamfering of electrostatic chuck surface
Solution Approach 1:
A protective film is applied to the surface part before plasma etching processes. This preliminary protective action prevents chamfering during cleaning operations, eliminating the need for dummy wafers. The protective film can be easily removed or replaced without opening the vacuum chamber, thus maintaining both productivity and heat transfer rate consistency.
Solution Approach 2:
The protective film serves as a cushioning layer that absorbs the harmful effect of plasma cleaning on the electrostatic chuck surface. By providing this beforehand protection, the actual electrostatic chuck surface is shielded from chamfering, ensuring consistent heat transfer rates while allowing aggressive cleaning without dummy wafers, thus maintaining productivity.
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
Enables precise management of the surface state of the electrostatic chuck and focus ring, preventing deterioration of etching characteristics and maintaining stable etching performance, thus improving the throughput of the plasma etching process.
Implementation Method 1
The electrostatic chuck serves to control the temperature of the wafer by adsorbing the wafer and transferring heat to the wafer
Implementation Method 2
plasma is generated and ions are injected into the placing table by applying a high-frequency power at a predetermined frequency to the upper electrode and the placing table
Implementation Method 3
by applying a high-frequency power at a predetermined frequency to the upper electrode and the placing table through a matching unit
Implementation Method 4
The focus ring is installed to distribute plasma on the surface of the wafer with high uniformity and etched together with the wafer by the ions
Implementation Method 5
the electrostatic chuck and the wafer have different thermal expansion coefficients, such that when the wafer is placed on the electrostatic chuck, the electrostatic chuck and the wafer rub against each other due to the difference between the thermal expansion coefficients
Data Source
AI summary
Provided is a substrate processing apparatus, including: transportation chamber maintained in an atmospheric environment where a substrate is transported; a vacuum processing chamber connected with the transportation chamber through a load lock chamber; a substrate placing table installed in the vacuum processing chamber and having a body part and a surface part that is attachable to/detachable from the body part; a storage unit installed in the load lock chamber or the transportation chamber and configured to receive the surface part; and a transportation mechanism configured to transport the substrate from the transportation chamber to the vacuum processing chamber through the load lock chamber and transport the surface part between the storage unit and the body part of the vacuum processing chamber.