Fixed Focus Ring Wafer Transfer via Pins and Slit Valve
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Solution Overview
Problem
Traditional focus rings in semiconductor wafer processing chambers require complex and expensive mechanisms for movement, which are inefficient and prone to damage from plasma or gas exposure during processes like PVD, CVD, and etching.
Innovation Solution
Implementing a fixed focus ring system where the focus ring is immobile and the wafer is moved vertically using pins and horizontally using a robotic arm through a slit valve, allowing for uniform plasma or gas distribution without exposing moving parts to processing media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a movable focus ring with lift mechanism is used, then the wafer can be transferred under the focus ring, but the mechanism requires large overhead and expensive hardware while exposing moving parts to plasma or gas damage
Solution Approach 1:
Instead of moving the focus ring to enable wafer transfer, the patent inverts the approach by keeping the focus ring fixed and moving the wafer vertically using pins that extend through the base. This eliminates the complex lift mechanism while achieving the same operational goal of wafer transfer under the focus ring.
Solution Approach 2:
The patent extracts the movement function from the focus ring itself and transfers it to separate pin elements that extend vertically from the base. This separates the focus ring's primary function (focusing plasma/gas) from the wafer transfer function, eliminating the need for a complex lift mechanism.
2Ease of operation
If a movable focus ring is used, then wafer access is enabled, but the moving parts are exposed to plasma or gas during processing which causes damage
Solution Approach 1:
Instead of moving the focus ring for wafer access, the patent keeps the focus ring stationary and moves the wafer vertically using pins. This inversion protects the focus ring from exposure to plasma or gas while maintaining full wafer accessibility for processing.
Solution Approach 2:
The patent introduces pins as an intermediary element between the base and the wafer. These pins enable vertical wafer movement and access without requiring the focus ring to move, thereby protecting the focus ring from harmful plasma or gas exposure during processing operations.
3Device complexity
If a fixed focus ring is used, then hardware is simplified and damage is reduced, but wafer transfer requires alternative mechanisms
Solution Approach 1:
The patent segments the wafer transfer function into two independent movements: vertical movement achieved by pins extending through the base, and horizontal movement achieved by a robotic arm through a slit valve. This segmentation simplifies the overall system by eliminating the need for a complex integrated lift mechanism while maintaining full wafer transfer capability.
Solution Approach 2:
The robotic arm serves multiple functions: it performs horizontal wafer transfer through the slit valve and can also position wafers for processing. This multi-functional approach reduces the need for specialized mechanisms, simplifying the overall hardware while maintaining operational effectiveness.
Data Source
AI summary
In an embodiment, a system includes: a base with a bore hole, wherein the base is configured to secure a wafer at a first position on the base; a pin extending through the bore hole; a focus ring horizontally surrounding the wafer at the first position and extending upwardly from the base, wherein the wafer is configured to be moved vertically between the first position and a second position above the focus ring via the pin; and a slit valve above the focus ring, wherein the wafer is configured to be moved horizontally between the second position and the slit valve via a robotic arm.