Two-Level Wafer Transfer Between Processing and Cleaning Stages
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Solution Overview
Problem
Current semiconductor wafer processing systems face inefficiencies in substrate processing, particularly in the sequential transfer and cleaning of wafers between grinding, polishing, and cleaning stages, leading to contamination risks and increased footprint, which affects processing yield and efficiency.
Innovation Solution
A substrate processing system is designed with a carry-in/out unit, processing unit, cleaning unit, first transfer unit stacked on top of the cleaning unit, and a second transfer unit, facilitating sequential processing and cleaning stages while minimizing contamination and footprint through a shuttle transfer device and wafer transfer devices, enabling efficient grinding, polishing, and cleaning operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple multi-joint substrate transfer robots are arranged sequentially for transferring wafers between grinding, polishing, and cleaning stages, then substrate processing can be completed, but the system occupies a large footprint area and increases complexity of substrate transfer paths
Solution Approach 1:
The patent introduces a vertical stacking arrangement where transfer units are positioned at different heights (first transfer unit at first height, second transfer unit at second height). This three-dimensional configuration allows substrate transfer paths to overlap vertically, significantly reducing the horizontal footprint area while maintaining the necessary transfer functionality between grinding, polishing, and cleaning stages.
Solution Approach 2:
The patent implements nested transfer paths where the second substrate transfer path is positioned within the spatial envelope of the first substrate transfer path. The second transfer unit operates at a different height level, allowing its transfer trajectory to be nested within the volume occupied by the first transfer unit's path, thereby reducing overall system complexity and footprint.
2Reliability
If cleaning unit is placed after processing unit in sequential arrangement, then cleaning function is provided, but contamination risk increases during transfer between units
Solution Approach 1:
The patent introduces a clean chamber as an intermediary environment between the processing unit and cleaning unit. The second transfer unit transfers substrates through this clean chamber, which provides a controlled low-contamination environment. This intermediary space acts as a buffer that protects substrates from contamination during transfer, while the stacked configuration minimizes the additional footprint required.
3Productivity
If multiple transfer robots are used for sequential substrate transfer, then complete processing workflow is achieved, but processing time increases due to sequential operations
Solution Approach 1:
The patent enables continuous substrate processing by allowing multiple substrates to be transferred simultaneously through overlapping transfer paths at different heights. While one substrate is being processed in the grinding stage, another can be transferred through the polishing stage, and a third through the cleaning stage. This parallel operation eliminates idle time between sequential steps, maintaining continuous useful action throughout the system.
Solution Approach 2:
The patent implements dynamic coordination between multiple transfer units operating at different height levels. The transfer operations are synchronized such that substrates move through different processing stages at optimally timed intervals, allowing the system to adapt its transfer rhythm to maintain maximum throughput without bottlenecks.
Data Source
AI summary
A substrate processing system configured to process a substrate includes a carry-in/out unit configured to carry the substrate from/to an outside thereof; a processing unit configured to process a processing surface of the substrate; a cleaning unit provided between the carry-in/out unit and the processing unit when viewed from a top, and configured to clean the processing surface after being processed in the processing unit; a first transfer unit stacked on top of the cleaning unit, and configured to transfer the substrate; and a second transfer unit provided between the processing unit and the first transfer unit when viewed from the top, and configured to transfer the substrate. The first transfer unit transfers the substrate between the carry-in/out unit and the second transfer unit. The second transfer unit transfers the substrate between the first transfer unit and the processing unit and between the processing unit and the cleaning unit.