Wafer Processing Changeover for Continuous Multi-Cassette Grinding
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Solution Overview
Problem
Current grinding apparatuses face productivity issues and non-uniform wafer thickness due to stand-by times of processing units when switching between different processing conditions for wafers on multiple cassette stages.
Innovation Solution
A processing apparatus with multiple cassette stages, a chuck table, and a conveyance control system that allows continuous processing by automatically changing over processing conditions and conveying wafers between stages, reducing stand-by time and ensuring consistent wafer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the processing conditions are changed after completing processing of wafers in the first cassette, then different processing conditions can be applied to the second cassette, but the grindstone must stand by during the transition period, reducing productivity
Solution Approach 1:
The system prepares the next processing conditions in advance while the current batch is being processed. The conveyance control section is configured to change processing conditions proactively before the current cassette is fully processed, eliminating stand-by time and ensuring continuous operation.
Solution Approach 2:
The system maintains continuous processing by overlapping the processing of different cassettes with different conditions. While the first cassette is being processed under condition set A, the system prepares condition set B for the second cassette, ensuring the grindstone never stands by idle.
2Manufacturing precision
If the grindstone stands by during processing condition changes, then processing accuracy can be maintained, but the temperature in the processing chamber lowers, causing non-uniform wafer thickness
Solution Approach 1:
Processing conditions are changed in advance before the current batch completes, preventing temperature drops that would occur during stand-by periods. This ensures the processing chamber maintains stable temperature throughout continuous operation.
Solution Approach 2:
The system eliminates idle stand-by periods by continuously processing different cassettes under different conditions. The conveyance control section ensures seamless transitions between cassettes, maintaining constant temperature and preventing wafer thickness non-uniformity.
3Adaptability or versatility
If multiple cassettes are processed under different processing conditions, then diverse wafer types can be produced, but the system requires complex control to manage condition changes and wafer conveyance
Solution Approach 1:
The conveyance control section serves multiple functions: it manages wafer conveyance between cassettes, controls processing condition changes, and coordinates the grindstone operation. This multi-functionality reduces the need for separate control systems for each function.
Solution Approach 2:
The system automatically manages the complexity of condition changes and wafer conveyance through the conveyance control section. Once configured with multiple processing conditions, the system self-regulates the transitions between cassettes and conditions without requiring complex external control or manual intervention.
Data Source
AI summary
When processing of all the wafers accommodated in a first cassette mounted on a first cassette stage is ended, the last wafer is conveyed out from a holding surface of a chuck table, and the holding surface becomes vacant, the wafer accommodated in a second cassette mounted on a second cassette stage is immediately conveyed onto the holding surface, by control by a conveyance control section. When the wafer to be held by the holding surface is changed from the wafer conveyed out from the first cassette to the wafer conveyed out from the second cassette, processing conditions are changed over to the processing conditions corresponding to the second cassette stage, by changeover control by a changeover section.