Vacuum Wafer Transfer Particle Detection by Pressure-Driven Gas Flow
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Solution Overview
Problem
Existing vacuum processing apparatuses face challenges in accurately identifying object generation sources due to the dispersion of particles during transfer, leading to reduced yield in semiconductor manufacturing.
Innovation Solution
An objects detecting method that increases the internal pressure of the transfer chamber to generate a gas flow, transfers the wafer through this flow to specific positions, and collects objects adhering to the wafer surface for precise detection of generation sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only exhaustion is performed by a dry pump at the time of sitting, then the vacuum is maintained, but the degree of dispersion increases and object generation sources cannot be specified
Solution Approach 1:
The patent applies dynamics by switching between different exhaust pump operations (dry pump only vs. combined turbo molecular pump and dry pump) depending on the process stage. During the sitting period, both pumps operate together to maintain laminar flow and reduce particle dispersion, enabling accurate object generation source detection. This dynamic adjustment resolves the contradiction between maintaining vacuum stability and achieving precise measurement.
Solution Approach 2:
The patent changes the operational parameters of the exhaust system by introducing a turbo molecular pump in addition to the dry pump during the sitting period. This parameter change transforms the flow regime from molecular flow (high dispersion) to laminar flow (low dispersion), thereby improving object generation source detection accuracy while maintaining vacuum conditions.
2Measurement precision
If particles are collected during transfer, then object generation can be detected, but the dispersed particles make it difficult to locate specific generation sources
Solution Approach 1:
The patent dynamically adjusts the exhaust pump operation during the sitting period to create laminar flow conditions. This reduces particle dispersion and preserves spatial information about particle origins, allowing accurate identification of object generation sources while still enabling particle collection and detection.
Solution Approach 2:
The patent introduces a sitting period as an intermediary step between transfer and processing. During this period, particles are allowed to settle and be collected under controlled laminar flow conditions, preserving spatial information. This intermediary process enables both particle detection and source location identification.
3Productivity
If maintenance operations are performed without accurate object detection, then processing can continue, but objects may adhere to processed wafers and yield is impaired
Solution Approach 1:
The patent performs preliminary particle collection and object generation source identification during the sitting period before wafer processing. By detecting and locating objects in advance, the system can perform targeted maintenance operations, ensuring processing reliability and yield improvement while maintaining productivity.
Solution Approach 2:
The patent implements a feedback mechanism where particle collection results from the sitting period inform maintenance decisions. The detected object generation sources provide feedback that guides targeted cleaning or replacement operations, ensuring that maintenance is performed only where necessary, thus maintaining both productivity and reliability.
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
Accurately detects object generation sources, preventing their formation and improving processing yield by enabling targeted maintenance and cleaning operations.
Implementation Method 1
increasing an internal pressure of the transfer chamber to be higher than an internal pressure of the processing chamber to generate a gas flow in the passage
Implementation Method 2
collecting the objects which fall to adhere to a surface of the wafer
Data Source
AI summary
An objects detecting method for a vacuum processing apparatus equipped with: a processing unit including a vacuum container having therein a processing chamber in which a wafer is processed, and an exhaust pump that exhausts gas in the processing chamber; a vacuum transfer unit including a transfer chamber in which the wafer is transferred; and a connection pipe including a passage through which the wafer can be transferred between the processing chamber and the transfer chamber, includes: an objects collecting process of increasing an internal pressure of the transfer chamber to be higher than an internal pressure of the processing chamber to generate a gas flow in the passage from the transfer chamber toward the processing chamber, transferring the wafer to a position straddling the transfer chamber, the passage, and the processing chamber, and holding the wafer for a predetermined time; and an objects detecting process of detecting objects adhering to a surface of the wafer.