Semiconductor structure and manufacturing method thereof

Abstract

The invention discloses a semiconductor structure and a manufacturing method thereof. The semiconductor structure comprises a semiconductor substrate; a sacrificial layer on the semiconductor substrate; a functional layer located on the sacrificial layer; a pad on the functional layer; a protection layer which covers the functional layer and includes an opening through which the pad is exposed; and at least one through hole penetrating through the protection layer and the functional layer, and at least part of the sacrificial layer is exposed through the at least one through hole. In the semiconductor structure, the bonding pad is formed on the functional layer and exposed through the opening of the protection layer, so that after a part of the sacrificial layer is removed through the through hole, the protection layer does not need to be removed, the subsequent lead process can be directly carried out on the exposed bonding pad, the purpose of simplifying the manufacturing process steps is achieved, the production efficiency is improved, and the manufacturing cost is reduced.

Description

technical field [0001] The present disclosure relates to the field of semiconductor device manufacturing, and more particularly, to a semiconductor structure and a manufacturing method thereof. Background technique [0002] With the development of Micro-Electro-Mechanical System (MEMS) technology, high-precision devices such as acceleration sensors, gyroscopes, and angular velocity sensors manufactured using MEMS technology have been widely used in the automotive and consumer electronics fields. middle. Among them, inertial sensors such as accelerometers and angular velocity meters all have movable structures, and MEMS often need to remove the sacrificial layer through a "release" process to make movable structures. [0003] The common release process is divided into dry method and wet method. The dry process has high cost and low efficiency, but the etching effect is well controllable, and it is often used to make complex MEMS structures. The wet process has high efficie...

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Problems solved by technology

[0005] However, when the wet etching process is adopted, the solution therein often has undercutting phenomenon based on the capillary effect based on the surface force. Since there is a gap between the protective layer 130 and the side of the step, the wet solvent often appears along the figure 1 The gap shown in the middle dotted frame drills into the etching sacrificial layer 110, resulting in the release of the protection area, and may even lead to hollowing out under the pad 140, and the pad 140 is broken during subsequent wiring, and finally the product fails

[0006] In addition, after releasing the structure, the subsequent deglue step increases the complexity of production, reduces production and efficiency and yield

If you use a wet method to remove glue, it is difficult to remove it at one time, because the structure after release is very fragile. In the microscopic world, the surface force (such as friction) is far greater than the physical force (such as gravity), so the impact of liquid can easily cause release. Fragmentation of the structure after failure

If a dry method is used to remove the glue, usually by plasma, its side effect will cause the released functional layer 120 to be bombarded, thus affecting the reliability of the functional layer 120

At the same time, if the temperature of the dry process is too high (for example, exceeding 300 degrees Celsius), the material of the pad 140 will be denatured or an undesired alloy will be formed, thereby affecting the subsequent wiring step of the pad 140

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