Alignment method for improving the alignment accuracy between the substrate and the mask in the evaporation machine

Abstract

An alignment method for improving alignment precision between a substrate and a photemask at an evaporation machine comprises the steps that: a processing unit captures a plurality of boundary extraction ranges at one periphery of a mark image; the processing unit captures multiple columns of image columns at each boundary extraction range, and each image column has a plurality of pixels; the processing unit converts the pixels to a plurality of intensity values, wherein each intensity value is a function of a pixel position corresponding to one pixel; the processing unit obtains a curve equation of each intensity value according to the intensity values; the processing unit is subjected to quadratic differential of the curve equation to obtain a point of inflexion of the curve equation and define the point of inflexion of the curve equation as a boundary point of the corresponding image column; and the processing unit calculates one mark center of the mark according to the boundary point of each image column.

Description

technical field [0001] The invention relates to an alignment method, in particular to an alignment method for improving the alignment accuracy between a substrate and a photomask in an evaporation machine. Background technique [0002] In the evaporation process of organic light-emitting diodes, a photomask with openings is mainly placed in front of the substrate, so that the vaporized light-emitting molecules adhere to the substrate through the openings on the photomask. In order to allow the light-emitting molecules to accurately attach to the substrate On the surface, the alignment accuracy between the mask and the substrate needs to reach 1 micron (μm). When it is desired to use an image capture device to perform alignment between the mask and the substrate, since the minimum unit of the image captured by the image capture device is 1 pixel (pixel), the alignment accuracy between the mask and the substrate cannot meet the requirements. This in turn results in lower prod...

AI Technical Summary

Problems solved by technology

When it is desired to use an image capture device to perform alignment between the mask and the substrate, since the minimum unit of the image captured by the image capture device is 1 pixel (pixel), the alignment accuracy between the mask and the substrate cannot meet the requirements. As a result, the product yield rate is reduced and the manufacturing cost is increased.

Images