Redesign of the Centring Unit in the Wafer Handler

Redesign of the Centring Unit in the Wafer Handler

de Sonnaville, Rudolf (TU Delft Mechanical, Maritime and Materials Engineering)

Herder, J.L. (mentor)

Delft University of Technology

2022-12-14

Background
One of VDL most complex products is the Wafer Handler a machine with the function of thermal conditioning, centering and aligning wafers for the subsequent photolithography processes. The function of centering a wafer is performed by a submodule of the WH, the Centring Unit (cu) Currently the CU has two main limitations which make it unfit for the next generation WH, it is dependent on the subfunction of an otherwise redundant module, and its performance it not optimal. The goal of the research is to develop a future-proof solution for the CU, which is compatible with the next generation WH. The specific objectives of the research are threefold: 1) to develop and identify innovative concept directions for the CU which address its current issues and provide better overall performance, 2) to select the most promising concept for detailed development and 3) to prove the feasibility of the most promising concept.
Method
First the origin of the problem of the CU was analysed to identify the functional requirements and design criteria for concept development. Subsequently, a long list of concept directions was developed and a selection was made to identify the best concept to perform the function of the CU. This concept was experimentally validated to demonstrate the feasibility of the selected concept.
Results
The concept design and selection phases resulted in the development of 6 acceptable concepts of which two concepts were selected for further development. Of these two concepts, the Photo Measurement System was selected as the best concept to perform the function of the CU. The PMS is a measurement system that measures the position error of a wafer when it enters the WH, this enables the subsequent modules to correct the position error. The feasibility of the PMS has been proven via experimental validation, as the measurement uncertainty (38.1 µm) falls within the defined requirement for uncertainty (functional requirement of the position measurement is 55µm).
Conclusion
In this study an innovative concept has been developed to perform the function of CU in next generation WH. The PMS allows the subsequent module to the CU to correct the position error of an incoming wafer, making the current CU redundant. This research allows for future-proof centering in the next generation WH.

VDL ETG
Centring Unit
Position module
Measurement system
Computer Vision
Concept Development
Design

http://resolver.tudelft.nl/uuid:abf7b54e-f4bb-4e16-9fea-14fb368624f5

Student theses

master thesis

© 2022 Rudolf de Sonnaville