Semiconductor structure and manufacturing method thereof

Abstract

The invention discloses a semiconductor structure and a manufacturing method thereof. The semiconductor structure comprises a device layer, an isolation layer, a corrosion barrier layer, a self-limiting corrosion cavity, a first corrosion cavity and a substrate; the device layer is located on the first side of the substrate, the self-limiting corrosion cavity is located on the second side of the substrate, and the isolation layer and the corrosion barrier layer are located on the side, close to the device layer, of the self-limiting corrosion cavity. The self-limiting corrosion cavity is located in a space defined by the isolation layer and the corrosion barrier layer; the first corrosion cavity is located on the side, away from the device layer, of the self-limiting corrosion cavity; and the first corrosion cavity communicates with the self-limiting corrosion cavity. According to the semiconductor structure and the manufacturing method thereof provided by the invention, the self-limiting corrosion cavity on the second side of the substrate is limited by the corrosion barrier layer formed on the first side of the substrate, so that the patterns on the first side and the second side of the substrate can be positioned and aligned on the first side of the substrate, and the self-limiting corrosion cavity is not influenced by errors of double-sided photoetching; and the alignment precision of the self-limiting corrosion cavity and the device layer is improved.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of semiconductor manufacturing, and in particular, to a semiconductor structure and a manufacturing method thereof. Background technique [0002] In the semiconductor process, double-sided processing is required in some cases, for example, patterns need to be made on the front and back sides of the silicon wafer, especially for some MEMS devices, such as pressure sensors, thermopile temperature sensors and other MEMS devices. Do deep etching so that the final device is a thin film device. Among them, the double-sided processing process requires the use of special equipment double-sided lithography machine, and deep etching can use dry etching or wet etching. [0003] The double-sided lithography machine adopts proximity or contact exposure, that is, the optical system projects the pattern on the silicon wafer at a ratio of 1:1, so the mask used is the same size as the silicon wafer, an...

AI Technical Summary

Problems solved by technology

However, inaccurate alignment is common when placing masks manually, including center deviation, that is, the center of the exposure pattern will deviate from the center of the wafer, and the maximum deviation will reach more than ten millimeters; it also includes rotation deviation, that is, the exposure pattern is relative to the wafer. The flat side of the circle will rotate, up to tens of degrees

Although skilled engineers can overcome this problem to a large extent, alignment accuracy is still affected by operational proficiency

[0004] When the pattern on the front and back of the silicon wafer forms a certain deviation, the pattern after deep etching will continue to maintain this deviation, or even amplify this deviation, which will adversely affect the performance of the device

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