Automatic wafer centering method

Abstract

The invention discloses an automatic wafer centering method, which comprises the following steps of: acquiring a wafer edge signal by a sensor in the process of taking back a wafer by a manipulator, obtaining the current center position of the wafer through an algorithm, comparing the current center position of the wafer with the teaching center position of the wafer, and compensating in the process of sending out the wafer next time by the manipulator if a deviation exists; and when the wafer gap just falls in one sensor detection area, rejecting the measurement result of the sensor in the gap area through an algorithm. According to the method, a machine table does not need to additionally increase stations, a mechanical arm can measure and compensate the wafer offset in the wafer conveying process, the equipment productivity is not affected at all, and the cost is far lower than that of a traditional mechanical centering unit and an optical centering unit.

Description

technical field [0001] The invention belongs to the field of electronic semiconductors, in particular to an automatic wafer centering method. Background technique [0002] In electronic semiconductor production and processing equipment, the wafer handling manipulator is responsible for the transfer of wafers between various stations. It is the core moving part of the machine. Its positioning accuracy directly determines the accuracy of wafer placement. The accuracy of the placement position determines the yield rate of chip processing. Therefore, it is particularly important to improve the accuracy of manipulator wafer pick-and-place. In order to improve the accuracy of the wafer placement by the manipulator, before the wafer is sent into the key process unit, such as before entering the glue uniform unit, the wafer is first put into the mechanical or optical centering unit, which can ensure that each time the wafer is sent into the process The chips of the unit are all lo...

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Problems solved by technology

[0003] 1) The mechanical centering unit is centered by mechanical clamping, and its disadvantage is that the accuracy is low (±0.2mm)

[0004] 2) The optical centering unit mainly processes the wafer through optical measurement, and its disadvantage is that the centering speed is relatively slow

[0005] 3) Regardless of whether mechanical alignment or optical alignment is used, several stations will be added, which will not only increase the equipment cost, but also reduce the equipment production capacity and equipment space utilization rate, and it is impossible to accurately control the position of each transfer of the wafer. real time monitoring

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