	US 12,174,398 B2
	Method for forming micro-lens array and photomask therefor
Jyun-You Lu, Tianzhong Township, Changhua County (TW); Hsin-Yen Tsai, Zhudong Township, Hsinchu County (TW); and Hao-Min Chen, Chiayi (TW)
Assigned to VISERA TECHNOLOGIES COMPANY LIMITED, Hsin-Chu (TW)
Filed by VisEra Technologies Company Limited, Hsin-Chu (TW)
Filed on Apr. 12, 2021, as Appl. No. 17/228,031.
Application 17/228,031 is a continuation of application No. 15/970,054, filed on May 3, 2018, abandoned.
Prior Publication US 2021/0231840 A1, Jul. 29, 2021
Int. Cl. G03B 3/00 (2021.01); G02B 3/00 (2006.01); G03F 1/50 (2012.01); G03F 7/00 (2006.01); H01L 27/142 (2014.01); H01L 27/146 (2006.01)

CPC G02B 3/0012 (2013.01) [G03F 7/0007 (2013.01); H01L 27/14627 (2013.01)]

6 Claims

1. A method for forming a micro-lens array comprising:

providing a substrate;

forming a plurality of photo-sensors in the substrate and arranging the photo-sensors to form a photo-sensor array;

forming a filter layer on the substrate;

forming an under layer directly on the filter layer;

forming a hard-mask layer on the under layer;

performing a lithography process on the hard-mask layer by a photomask to form a first pattern and a plurality of second patterns;

reflowing the first pattern and the plurality of second patterns to form a first lens structure and a plurality of second lens structures respectively; and

etching the under layer by using the first lens structure and the plurality of second lens structures as an etching mask to form a first micro-lens and a plurality of second micro-lenses respectively,

wherein the photomask comprises:

a first transparent region;

a first pattern segment corresponding to the first pattern; and

a plurality of second pattern segments corresponding to the plurality of second patterns respectively,

wherein the first pattern segment is opaque,

wherein the first pattern segment and the plurality of second pattern segments are separated by a plurality of portions of the first transparent region, the plurality of second pattern segments surround the first pattern segment, and a shape of the first pattern segment is different from a shape of each of the plurality of second pattern segments,

wherein the shape of the first pattern segment is rectangular, and each of the plurality of second pattern segments is a square,

wherein each of the plurality of second pattern segments comprises an opaque square region with nine openings disposed on a center area of the opaque square region, and a space between the nine openings is transparent,

wherein an area of the second transparent region of the second pattern segment is larger than 18% and smaller than 50% of an area of the second pattern segment, and

wherein the first pattern segment and each of the plurality of second pattern segments correspond to a single micro-lens.