CN-116133361-B - Semiconductor structure and forming method thereof

Abstract

The invention relates to a semiconductor structure and a forming method thereof. The method for forming the semiconductor structure comprises the steps of forming a capacitor substrate, forming a protective layer at least covering the top surface of the capacitor switching structure, forming an isolation layer which fills the gap and covers the surface of the protective layer, removing the isolation layer which covers the top surface of the protective layer to expose the protective layer, and removing the protective layer to expose the capacitor switching structure. The invention avoids the short circuit problem between adjacent capacitor switching structures, improves the yield of the semiconductor structure and improves the electrical property of the semiconductor structure.

Inventors

• WANG PEIMENG
• LU JINGWEN
• XI NING

Assignees

• 长鑫存储技术有限公司

Dates

Publication Date

20260508

Application Date

20210804

Claims (12)

1. 1. A method of forming a semiconductor structure, comprising the steps of: forming a capacitor substrate, wherein the capacitor substrate comprises a plurality of capacitor switching structures and gaps between adjacent capacitor switching structures; forming a protective layer at least covering the top surface of the capacitor switching structure; Forming an isolation layer which fills the gap and covers the surface of the protection layer; removing the isolation layer covered on the top surface of the protection layer to expose the protection layer; Removing the protective layer to expose the capacitor switching structure; the specific steps of forming the protective layer at least covering the top surface of the capacitor switching structure include: passivating the surface of the capacitor transfer structure to form the protective layer covering the surface of the capacitor transfer structure; the specific steps of passivating the surface of the capacitor transfer structure include: nitriding the surface of the capacitor switching structure; The capacitor transfer structure is made of metal material, and the specific steps of nitriding the surface of the capacitor transfer structure include: And treating the surface of the capacitor transfer structure by adopting nitrogen source gas to form metal nitride serving as the protective layer, wherein the nitrogen source gas comprises H 2 、O 2 and NH 3 .
2. 2. The method of forming a semiconductor structure of claim 1, wherein forming a protective layer at least covering a top surface of the capacitor transfer structure comprises: and forming a protective layer covering the top surface and the side wall of the capacitor switching structure.
3. 3. The method of claim 1, wherein removing the spacer layer overlying the top surface of the protective layer comprises: and removing the isolation layer covered on the top surface of the protection layer by adopting a dry etching process.
4. 4. The method of claim 1, wherein the spacer layer is made of nitride material, and the step of removing the spacer layer covering the top surface of the protective layer by dry etching comprises the following steps: and etching the isolation layer by using the mixed gas of CF 4 、CHF 3 and O 2 as etching gas.
5. 5. The method of forming a semiconductor structure of claim 1, wherein removing the protective layer comprises: And removing the protective layer by adopting a wet etching process.
6. 6. The method of claim 4, wherein the material of the protective layer is a metal nitride material, and the step of removing the protective layer by wet etching comprises: And removing the protective layer on the top surface of the capacitor transfer structure by adopting deionized water or an organic solvent.
7. 7. The method of claim 1, further comprising the steps of, after removing the protective layer and exposing the capacitor transfer structure: and cleaning the surface of the capacitor switching structure.
8. 8. The method of claim 7, wherein the cleaning the surface of the capacitor transfer structure comprises: removing particles and a natural oxide layer on the surface of the capacitor switching structure by adopting a wet cleaning process; And drying the capacitor switching structure.
9. 9. A semiconductor structure formed by the method of forming a semiconductor structure as claimed in any one of claims 1 to 8, the semiconductor structure comprising: The capacitive substrate comprises a plurality of capacitive switching structures; the isolation layer is positioned between the adjacent capacitance switching structures and is used for isolating the adjacent capacitance switching structures; and the protective layer covers part of the side wall of the capacitor switching structure.
10. 10. The semiconductor structure of claim 9, further comprising: and the diffusion barrier layer covers the bottom surface and part of the side wall of the capacitor switching structure.
11. 11. The semiconductor structure of claim 10, wherein the diffusion barrier layer and the protective layer collectively cover an entire sidewall of the capacitor transfer structure.
12. 12. The semiconductor structure of claim 9, wherein the protective layer has a thickness of 0.5nm to 5nm.

Description

Semiconductor structure and forming method thereof Technical Field The present disclosure relates to integrated circuit technology, and more particularly, to a semiconductor structure and a method for forming the same. Background Dynamic random access memory (Dynamic Random Access Memory, DRAM) is a semiconductor structure commonly used in electronic devices such as computers and is made up of a plurality of memory cells, each of which typically includes a capacitor for storing charge and a transistor for accessing the capacitor. The gate of the transistor is electrically connected with the word line, the source is electrically connected with the bit line, the drain is electrically connected with the capacitor, and the word line voltage on the word line can control the on and off of the transistor, so that the data information stored in the capacitor can be read through the bit line or written into the capacitor. The capacitor is connected with the drain electrode through a capacitor transfer structure in the capacitor substrate. However, due to the limitation of the current manufacturing process, defects are easily generated on the surface of the capacitor substrate, and short circuits are easily generated between adjacent capacitor switching structures. Therefore, how to reduce the defects on the surface of the capacitor substrate and avoid the short circuit between the adjacent capacitor switching structures so as to improve the electrical performance of the semiconductor structure is a technical problem to be solved currently. Disclosure of Invention The invention provides a semiconductor structure and a forming method thereof, which are used for solving the problems that the surface of a capacitor substrate is easy to generate defects and the adjacent capacitor switching structures are easy to generate short circuits so as to improve the electrical performance of the semiconductor structure. According to some embodiments of the present application, an aspect of the present application provides a method for forming a semiconductor structure, including: forming a capacitor substrate, wherein the capacitor substrate comprises a plurality of capacitor switching structures and gaps between adjacent capacitor switching structures; forming a protective layer at least covering the top surface of the capacitor switching structure; Forming an isolation layer which fills the gap and covers the surface of the protection layer; removing the isolation layer covered on the top surface of the protection layer to expose the protection layer; and removing the protective layer to expose the capacitor switching structure. In some embodiments, the specific step of forming a protective layer at least covering the top surface of the capacitor switching structure includes: and forming a protective layer covering the top surface and the side wall of the capacitor switching structure. In some embodiments, the specific step of forming a protective layer at least covering the top surface of the capacitor switching structure includes: And passivating the surface of the capacitor transfer structure to form the protective layer covering the surface of the capacitor transfer structure. In some embodiments, the specific step of passivating the surface of the capacitor transfer structure includes: and nitriding the surface of the capacitor switching structure. In some embodiments, the material of the capacitor transfer structure is a metal material, and the nitriding the surface of the capacitor transfer structure comprises the following specific steps: And treating the surface of the capacitor transfer structure by adopting nitrogen source gas to form metal nitride serving as the protective layer, wherein the nitrogen source gas comprises H 2、O2 and NH 3. In some embodiments, the specific step of removing the isolation layer covering the top surface of the protection layer includes: and removing the isolation layer covered on the top surface of the protection layer by adopting a dry etching process. In some embodiments, the material of the isolation layer is a nitride material, and the specific step of removing the isolation layer covering the top surface of the protection layer by using a dry etching process comprises the following steps: and etching the isolation layer by using the mixed gas of CF 4、CHF3 and O 2 as etching gas. In some embodiments, the specific step of removing the protective layer comprises: And removing the protective layer by adopting a wet etching process. In some embodiments, the material of the protective layer is a metal nitride material, and the specific step of removing the protective layer by adopting a wet etching process comprises the following steps: And removing the protective layer on the top surface of the capacitor transfer structure by adopting deionized water or an organic solvent. In some embodiments, the removing the protective layer, after exposing the capacitor switching structure, further inc