Micro-lens array integrated in image sensor and preparation method thereof

Abstract

The invention discloses a preparation method of a micro-lens array integrated in an image sensor. The preparation method comprises the following steps: S01, forming a light barrier on the upper surface of a substrate; S02, covering the upper surfaces of the light barrier and the substrate with M flat layers, and controlling the number of the flat layers so that the included angle between the uppermost flat layer located on the edge of the light barrier and the substrate is made to be (0 degree, 30 degrees), wherein M is a positive integer greater than 0; S03, depositing an etching layer on theflat layer; S04, photoetching a micro-lens array in the etching layer, wherein the micro-lens array is located between the light barriers. According to the micro-lens array integrated in the image sensor and the preparation method of the micro-lens array, the micro-lens fusion phenomenon can be effectively avoided, and the sensitivity of the image sensor is improved.

Description

technical field [0001] The invention relates to the field of microlenses, in particular to a microlens array integrated in an image sensor and a preparation method thereof. Background technique [0002] The microlens array is an array composed of a series of tiny lenses with diameters ranging from a few micrometers to hundreds of millimeters in a certain arrangement. It is widely used in optical information processing, beam shaping, optical device interconnection, three-dimensional imaging and other fields. [0003] High-sensitivity and high-resolution imaging detection systems usually require image sensors with high responsivity and detection rate, low noise, large number of pixels, small pixel size and large fill factor. Due to the difficulties in material preparation and process manufacturing, these requirements are generally difficult to achieve at the same time. For example, the improvement of spatial resolution can be achieved by reducing the size of the pixel and incr...

AI Technical Summary

Problems solved by technology

It is worth noting that, as attached figure 1 As shown in the above steps, the flat layer 3 is globally covered, that is, it is covered on the light blocking plate 2 and the substrate 1 at the same time. Since the light blocking plate 2 has a certain height, the flat layer 3 around the light blocking plate 2 is not flat. Instead, it has a certain included angle with the substrate, which is generally 70-80°; the included angle on the flat layer makes the etching layer deposited on the flat layer also have a corresponding included angle, and at the same time, due to the The etch layer needs to be etched into microlenses, especially for uneven areas, the difference in the lithography angle of the microlenses is caused during the etching process, thus forming the phenomenon of microlens fusion, such as attached figure 1 As shown; that is, the microlenses located in the uneven area are connected together, making the microlenses abnormal in shape and affecting the sensitivity of the image sensor

Images