Clamshell Load Lock with Movable Bottom Wall for Fast Pumping
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Solution Overview
Problem
Conventional load locks have a significant volume, which prolongs the time required for pumping down to vacuum conditions, thereby reducing the throughput in semiconductor manufacturing and handling processes.
Innovation Solution
A load lock design featuring a movable bottom wall that reduces the internal volume, allowing faster pumping and venting, with a sealing mechanism and actuator-controlled movement to optimize the chamber's volume during operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the load lock chamber has a significant volume to accommodate robotic mechanisms for workpiece introduction and removal, then the workpiece transfer capability is improved, but the time required to pump down the chamber to vacuum conditions increases, reducing throughput
Solution Approach 1:
The load lock chamber volume is made dynamic through a movable bottom wall that can change position between a first position (creating small internal volume for pumping) and a second position (allowing workpiece contact with process chamber). This dynamic volume adjustment allows the system to optimize between throughput (small volume during pumping) and workpiece transfer capability (larger effective volume during transfer operations).
Solution Approach 2:
The load lock chamber is segmented into different operational states by the movable bottom wall, creating distinct volume configurations: a small sealed volume for rapid pumping and a larger effective volume for workpiece handling. This segmentation allows each operational phase to have optimized volume characteristics.
2Productivity
If the load lock chamber volume is reduced to increase throughput, then the pump-down time is decreased, but the capability to accommodate robotic mechanisms for workpiece introduction and removal is compromised
Solution Approach 1:
The movable bottom wall enables the chamber to dynamically adjust its volume based on operational requirements. During pumping operations, the wall is in the first position creating a small volume for fast pump-down. During workpiece transfer, the wall moves to the second position to provide adequate space for robotic mechanisms, thus resolving the contradiction between throughput and operational capability.
Solution Approach 2:
The movable bottom wall introduces a dimensional change in the chamber volume by moving along the vertical axis. This allows the system to transition between different volume states without compromising the horizontal workspace needed for robotic operations, effectively adding a temporal-dimential aspect to the chamber configuration.
3Ease of operation
If the bottom wall is moved to allow workpiece contact with the process chamber, then the workpiece transfer is enabled, but the sealed chamber volume is compromised
Solution Approach 1:
The bottom wall transitions from a static sealed barrier to a dynamic element that can move between sealing positions and transfer positions. When moved to the second position, it enables workpiece contact with the process chamber while the sealing mechanism maintains vacuum integrity, thus enabling transfer without permanently compromising the sealed chamber volume.
Solution Approach 2:
The bottom wall is positioned in the first sealed position during pumping operations, and only moved to the second position after pumping is complete and the vacuum seal is established. This preliminary sealing action ensures that the chamber volume is optimized for pumping before the transfer operation begins, minimizing the impact on sealed volume.
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 reduced volume load lock enables faster air removal and pressure equalization, enhancing processing throughput by minimizing the time required for pump-down and vent-up operations.
Implementation Method 1
The bottom wall may be sealed in the first position through the use of a sealing mechanism, such as a magnetic clamp.
Implementation Method 2
a valve in communication with the upper chamber and in communication with a pump to extract air from the upper chamber
Data Source
AI summary
A load lock having a reduced volume, thereby allowing faster pumping and venting, is disclosed. The load lock uses a movable bottom wall to modify the volume of the chamber to be pumped. In a first position, the movable wall is disposed so as to create a small internal volume. In a second position, the bottom wall is moved downward, allowing the workpiece to be in contact with a process chamber or an exit aperture. The bottom wall may be sealed in the first position through the use of a sealing mechanism, such as a magnetic clamp. The bottom wall may also include a workpiece holding mechanism. The top wall may be a removable cover, which is moved by an actuator. A robotic mechanism may supply workpieces to the load lock while the top wall is in the open position.