Optical collimator and manufacturing method thereof

Abstract

The invention relates to an optical collimator and a manufacturing method thereof. The optical collimator comprises 2N-1 sub-collimators, wherein N is an integer greater than 1. A collimation hole isarranged in a first metal layer to form a first sub-collimator. A collimation hole is arranged in a second metal layer, which is above the first metal layer, to form a third sub-collimator. Between an(i-1)th metal layer and an i-th metal layer, an (i-1)th via layer exists. An (i-1)th via is arranged in the (i-1)th via layer. Then the (i-1)th via is filled by a metal to connect the (i-1)th metal layer and the i-th metal layer. The (i-1)th via layer is a (2i-2)th sub-collimator, wherein i is 2, 3, ..., N; and a collimation hole is arranged in an i-th metal layer, which is above an (i-1)th metallayer, to form a (2i-1)th sub-collimator of (2N-1) sub-collimators. The provided optical collimator and the manufacturing method thereof can improve the optical space filtering performance of the optical collimator.

Description

technical field [0001] The present application relates to the field of optical devices, and in particular, to an optical collimator and a manufacturing method thereof. Background technique [0002] With the advent of the era of full-screen mobile phones, under-screen fingerprint recognition has gradually become a technology hotspot. According to the difference in implementation principle, under-screen fingerprint recognition can usually be divided into three types: optical type, ultrasonic type and capacitive type. Among them, for the optical fingerprint identification module, a collimator is usually provided, which is used to guide the reflected light reflected from the surface of the finger to the image sensor below for optical detection. [0003] The collimator can be a separate optical component (discrete) or integrated into the image sensor (integrated). The advantage of a discrete collimator is that a high aspect ratio can be obtained, such as a through silicon via (...

AI Technical Summary

Problems solved by technology

The advantage of a discrete collimator is that it can obtain a high aspect ratio, such as through-silicon vias made by the Through Silicon Via (TSV) process, but its disadvantage is that the cost is high

The integrated collimator is realized based on the metal layer in the complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor, CMOS) back-end process. The advantage is that there is no additional process cost. Limited by the process, it is difficult to further improve the aspect ratio

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