Weighing Device Disturbance Element for Semiconductor Wafer Measurement
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Solution Overview
Problem
The existing methods for reducing variable errors in load cell output during semiconductor wafer weighing are time-consuming, requiring repeated loading and unloading of the wafer to stabilize the measurement, which affects wafer throughput.
Innovation Solution
A weighing device with a disturbance element that temporarily and controllably disturbs the measurement output while the wafer is loaded, allowing for multiple measurements to be averaged quickly without removing the wafer, thereby reducing variable errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measurements are performed by repeatedly loading and unloading the wafer to reduce variable errors, then measurement precision is improved, but wafer throughput deteriorates
Solution Approach 1:
The patent applies mechanical vibration by using a vibration element to disturb the load cell output while the wafer remains loaded. This vibration causes the output to fluctuate, allowing the system to capture multiple stable readings during the vibration period without removing the wafer. The vibration temporarily disrupts the locked output state, enabling multiple measurements to be taken in succession while maintaining wafer presence on the load cell.
Solution Approach 2:
The patent implements periodic action through the vibration element that oscillates at a frequency sufficient to disturb the load cell output multiple times within a measurement cycle. This periodic disturbance creates multiple opportunities for the output to settle at different stable values, allowing systematic averaging of multiple measurements while the wafer remains on the load cell throughout the entire measurement process.
2Measurement precision
If the wafer is removed and reloaded multiple times to obtain stable measurements, then variable errors are reduced, but time consumption increases
Solution Approach 1:
The vibration element provides a time-efficient method for obtaining multiple measurements by creating output fluctuations while the wafer remains loaded. This eliminates the need for repeated wafer removal and reloading, significantly reducing the time required to collect multiple stable readings for averaging while maintaining measurement precision.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the wafer on the load cell throughout the entire measurement process. The vibration element continuously disturbs the output to enable multiple readings to be captured in succession without interruption, eliminating idle time associated with wafer removal and reloading operations.
Data Source
AI summary
An apparatus comprising: a weighing device for generating measurement output indicative of the weight of an object loaded on the weighing device; and a disturbance element for temporarily disturbing the measurement output of the weighing device while the object is loaded on the weighing device.