Method for forming optical fingerprint identification device

Abstract

The invention provides a method for forming an optical fingerprint identification device, comprising: providing a silicon substrate, forming a groove array on the silicon substrate; providing a light-transmitting substrate and an image sensor chip, bonding the light-transmitting substrate and the image sensor chip, The light amount photolithography method forms a lens array on the light-transmitting substrate, and the lens array corresponds to the photosensitive array of the image sensor chip; bonding the groove surface of the silicon substrate to the light-transmitting substrate, and the groove array corresponds to the lens The non-groove surface of the silicon substrate is etched to expose the lens array, and a silicon light barrier is formed between adjacent lenses. The forming method of the optical fingerprint identification device of the present invention forms a lens array through the gradual light flux lithography method, which can meet the requirements for more precise and complex lens production, accurately guarantee the optical characteristics required by the optical fingerprint identification device, and is suitable for portable electronic devices. equipment, and is compatible with existing chip fabrication and packaging processes to reduce costs.

Description

technical field [0001] The invention relates to the field of image processing, in particular to a method for forming an optical fingerprint identification device. Background technique [0002] The current fingerprint identification schemes include optical technology, silicon technology (capacitive / radio frequency type), ultrasonic technology, etc. [0003] Optical technology The use of optical imaging equipment is based on the principle of total reflection of light (FTIR). The light hits the surface of the glass with fingerprints, and the reflected light is obtained by the image sensor. The amount of reflected light depends on the depth of the fingerprint ridges and valleys pressed on the surface of the glass, as well as the oil and moisture between the skin and the glass. After the light is shot to the center of the valley through the glass, it is totally reflected at the interface between the glass and the air, and the light is reflected to the image sensor, while the lig...

AI Technical Summary

Problems solved by technology

[0004] However, the current optical fingerprint identification devices are large in size and have a long optical path, so they cannot be applied to portable electronic devices such as mobile phones

Under the premise of limited volume, the fingerprint recognition device suitable for portable electronic devices such as mobile phones needs to use a lens with a finer and more complex three-dimensional surface to ensure the required optical properties, such as resolution. However, using traditional micro-processing technology, For example, anisotropic or isotropic dry etching and wet etching can only process surfaces with limited topography, and newly developed three-dimensional micromachining technologies such as multi-layer mask technology, laser three-dimensional lithography, and electron beam direct writing technology , there are problems such as poor accuracy, high cost, and low output, which cannot meet the production requirements of such high-precision devices.

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