Image sensor and formation method thereof

Abstract

The invention provides an image sensor and a formation method thereof. The method comprises the following steps: providing a first wafer, wherein the front surface of the first wafer has first liners; providing a second wafer, wherein the front surface of the second wafer has second liners, the second liners being in one-to-one correspondence with the first liners; and aligning the front surface of the first wafer to the front surface of the second wafer and carrying out bonding to make each first liner be electrically connected with the corresponding second liner, wherein the area of the surface of each first liner is smaller than the area of the surface of the corresponding second liner. The scheme can reduce the contact area of the first liners and the second liners, so that when there is a small degree of alignment deviation between the first wafer and the second wafer, the contact area is not affected, and alignment tolerance is broadened favorably.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to an image sensor and a forming method thereof. Background technique [0002] The image sensor is the core component of the camera equipment, which realizes the image capture function by converting the optical signal into an electrical signal. Taking Complementary Metal Oxide Semiconductor Image Sensors (CMOS Image Sensors, CIS) devices as an example, due to their advantages of low power consumption and high signal-to-noise ratio, they have been widely used in various fields. [0003] 3D-Stack CIS was developed to support the demand for higher quality images. Specifically, 3D-Stack CIS can separately manufacture the logic wafer and the pixel wafer, and then bond the front side of the logic wafer and the front side of the pixel wafer, because the pixel part and the logic circuit part are independent of each other , so the pixel part can be optimized for high-qu...

AI Technical Summary

Problems solved by technology

[0005] However, in the existing Cu-Cu wafer bonding technology, the problem of large alignment deviation between corresponding pads is prone to occur, resulting in increased resistance and reduced device performance.

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