Pixel structure of CIS chip, micro lens array, image sensor and manufacturing method

Abstract

The invention provides a pixel structure of a CIS chip, a micro lens array, an image sensor and a manufacturing method. The pixel structure comprises a semiconductor substrate which is provided with a photosensitive element, and a flat layer located above the semiconductor substrate. A first micro lens is a convex lens, the upper surface of the first micro lens is a convex surface, and the lower surface of the first micro lens is located right above the flat layer. A color filter layer is located on the upper surface of the first micro lens, and the upper surface and the lower surface of the color filter layer are convex surfaces. A second micro lens is a convex lens, the second micro lens is located on the upper surface of the color filter layer, and the upper surface and the lower surface of the second micro lens are convex surfaces. The upper surface of the first micro lens is set to be the convex surface, and the upper surfaces and the lower surfaces of the color filter layer and the second micro lens are set to be the convex surfaces, so that the light received by the pixel structure is totally refracted into the photosensitive element, and the imaging quality is improved.

Description

technical field [0001] The invention relates to the technical field of image sensors, in particular to a pixel structure of a CIS chip, a microlens array, an image sensor and a manufacturing method. Background technique [0002] With the improvement of semiconductor manufacturing technology, the field of application of complementary metal oxide semiconductor (complementary metal oxide semiconductor, CMOS) image sensor (CIS) chip is constantly enriched, and more and more requirements are put forward for the resolution of CIS chip. challenge. [0003] figure 1 It is a cross-sectional view of a traditional CIS chip pixel structure, which includes a single-layer micro-lens (micro-lens, ML) 104, a color filter layer 103, a flat layer 102 and a semiconductor substrate 100, visible through the single-layer micro-lens 104 When the light is refracted, only the middle part of the light passes through the color filter layer 103 and the flat layer 102 and is transmitted to the photose...

AI Technical Summary

Problems solved by technology

Wherein, the light on both sides of the single-layer microlens 104 cannot be refracted into the photosensitive element, resulting in the loss of the optical signal

[0004] In order to meet the requirements of high imaging resolution, the number of pixel structures in CIS chips is increasing continuously, resulting in the continuous reduction of the size of the pixel structure, so that the effective photosensitive area in the pixel structure is reduced, and the photodiode (photodiode, PD) receives The light becomes less, which reduces the optical efficiency of the CIS chip, which in turn causes a decrease in the sensitivity and imaging quality of the CIS chip.

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