Loadlock Chamber Venting for Throughput and Particle Control

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Solution Overview

Problem

Existing semiconductor processing systems face limitations in tool productivity and throughput due to sequential events such as workpiece transfer and environmental changes, leading to increased particle contamination and inefficiencies.

Innovation Solution

A system and method for optimizing the conditioning of a loadlock chamber by dynamically controlling vent gas pressure and flow based on the presence of a workpiece, using a controller to maximize throughput and minimize particle contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the loadlock chamber is evacuated and vented sequentially for each workpiece transfer, then the workpiece can be transferred between atmospheric and vacuum environments, but tool productivity and throughput are severely limited

Engineering Contradiction:

Improvetool productivityVSAvoidtime for sequential operations

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The system performs preliminary conditioning of the loadlock chamber by introducing vent gas to create a controlled atmosphere before workpiece transfer. This preliminary action prepares the chamber environment in advance, allowing faster subsequent operations and enabling parallel processing activities to occur simultaneously, thereby improving overall productivity without compromising workpiece integrity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The vent gas flow is maintained continuously or in near-continuous fashion during loadlock chamber operations, rather than being interrupted for each sequential step. This continuous action maintains a stable environment that supports uninterrupted workpiece transfers and enables overlapping of multiple processing activities, reducing total cycle time while maintaining product quality

Inventive Principle:

Principle #20Continuity of useful action

2Manufacturing precision

If workpiece transfer and environmental changes are performed sequentially, then proper orientation and positioning can be achieved, but particle contamination increases and throughput decreases

Engineering Contradiction:

Improveworkpiece orientationVSAvoidparticle contamination

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Vent gas is introduced into the loadlock chamber to create an inert or controlled atmosphere during workpiece transfer and environmental transitions. This controlled atmosphere prevents particle contamination by excluding contaminants while maintaining conditions suitable for precise workpiece orientation and positioning, thus eliminating the trade-off between precision and contamination

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The vent gas acts as an intermediary medium between the atmospheric and vacuum environments during workpiece transfer. It provides a controlled transitional environment that protects the workpiece from particle contamination while allowing necessary environmental changes and positioning operations to occur, thereby maintaining manufacturing precision without increasing contamination

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If conventional venting procedures are used, then the loadlock chamber can be evacuated and vented, but particle contamination concerns limit throughput optimization

Engineering Contradiction:

Improveworkpiece throughputVSAvoidparticle contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts vent gas flow rate and pressure parameters based on real-time detection of workpiece presence and processing stage. By optimizing these parameters continuously, the system achieves fast venting and evacuation cycles that maximize throughput while maintaining particle-free conditions through precise control of the vent gas atmosphere

Inventive Principle:

Principle #35Parameter changes

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

Enhances throughput by allowing parallel processing and reduces particle contamination through targeted venting strategies, thereby extending the time between preventive maintenance and lowering costs.

Implementation Method 1

A vent gas control device is provided and configured to selectively control one or more of a pressure and a flow rate of a vent gas from a vent gas source to the loadlock volume

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS20250279297A1Variable vent pressure and flow for flushing loadlock chamber

Publication Date: 2025.09.04 AXCELIS TECHNOLOGIES INC

AI summary

A workpiece processing system has a process chamber for processing a workpiece. A loadlock chamber has a workpiece support to support the workpiece. A vacuum isolation valve permits the workpiece to transfer between the workpiece support and the process environment. An atmospheric isolation valve permits the workpiece to transfer between the workpiece support and an atmospheric environment. A vent gas control device controls a pressure or a flow rate of a vent gas to the loadlock volume. A workpiece location system determines a presence of the workpiece on the workpiece support. The vent gas control device is controlled based on the workpiece being present on the workpiece support, the process time, and the vent time, maximizing the pressure or flow rate of the vent gas when the workpiece is not on the workpiece support, and maximizing conditioning of the loadlock chamber.