This paper sets out to propose a wafer prealigner based on multi‐sensor integration and an effective prealignment method implemented on it.
The wafer and notch eccentricities, on which wafer prealignment is based, are calculated with the peripheral data of the wafer detected by a laser displacement sensor and a transmission laser sensor by means of barycenter acquiring algorithm in a one‐particle system.
The center and notch prealignment precisions of the system are, respectively, ±1.5 μm and ±30 μrad. Experimentation has proved the validity and effectiveness of the system.
The wafer prealigner is a subsystem of the lithography in the semiconductor industry. The prealignment algorithm can be implemented in any object with random figures.
The periphery of the wafer is detected by a high‐precision laser displacement sensor and a low‐cost transmission laser sensor instead of a CCD linear sensor used by traditional wafer prealigners, which saves the space occupation of the structure and enhances the systematic prealignment precision. Using barycenter acquiring algorithm in a one‐particle system to calculate the wafer and notch eccentricities is effective and valid.
Huang, C., Cao, Q., Fu, Z. and Leng, C. (2008), "The development of a wafer prealigner based on the multi‐sensor integration", Assembly Automation, Vol. 28 No. 1, pp. 77-82. https://doi.org/10.1108/01445150810849046Download as .RIS
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