A kind of semiconductor device and its preparation method

Abstract

The invention relates to a semiconductor device and a preparation method thereof. The semiconductor device comprises a first joint wafer and a second joint wafer, a bonding pad in the first joint wafer is of a projection shape, a bonding pad in the second joint wafer is of a groove shape, and the shape and size of the projection match those of the groove respectively. The new joint wafer is provided to solve the problems in the prior art, the size of the bonding pads is adjusted and the joint appearance of a Cu pad is adjusted to improve the bonding yield rate and reliability.

Description

technical field [0001] The present invention relates to the field of semiconductors, and in particular, the present invention relates to a semiconductor device and a preparation method thereof. Background technique [0002] In the field of electronic consumption, multi-functional devices are more and more popular among consumers. Compared with devices with simple functions, the production process of multi-functional devices will be more complicated. For example, multiple chips with different functions need to be integrated on the circuit board. With the introduction of 3D integrated circuit (IC) technology, 3D integrated circuit (IC) is defined as a system-level integrated structure that stacks multiple chips in a vertical plane direction to save space, and the edge parts of each chip Multiple pins can be drawn as needed, and these pins can be used as needed to interconnect the chips that need to be connected to each other through metal wires, but the above method still has ...

AI Technical Summary

Problems solved by technology

The characteristic of the method is that the bonding stress (bonding force) is very large during the bonding process. When Cu protrudes (protrusion), the copper pad (Cu PAD) will be squeezed and deformed under the huge bonding stress (bonding force). It is possible to cause metal bridge, which will lead to the diffusion of metal copper (Cu diffuse) due to the contact between Cu and oxide (Oxide). In severe cases, it may cause cracking (crack) due to high pressure, such as Figure 1b and 1c shown

[0006] Usually, the medium used to block the oxide diffuse of Cu in the Cu process is SiN, but adding a SiN protective layer on the wafer surface will result in poor bonding quality.

[0007] Therefore, although there is a method of Cu-Cu bonding at the wafer level (Wafer level Cu-Cubonding) in the prior art, there are various disadvantages in the prior art, such as bonding alignment (bonding alignment), bonding quality problems (Bonding quality issue), wafer stress causes wafer edge bonding failure (wafer stressinduce wafer edge bonding fail) and copper diffusion (Cu diffuse issue), the above drawbacks have become urgent problems to be solved to further improve device performance and yield

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