CN-122028718-A - Semiconductor device and method for manufacturing the same

Abstract

The invention provides a semiconductor device and a manufacturing method thereof, the method comprises the steps of providing a substrate, forming an oxide layer and a nitride layer on the substrate, etching the nitride layer, the oxide layer and the substrate with partial thickness to form a shallow trench, and forming an isolation material layer which fills the shallow trench and covers the nitride layer; the isolation material layer is planarized to the thickness of the isolation material layer on the rest part of the nitride layer, the rest isolation material layer on the nitride layer and the nitride layer are removed to enable the upper surface of the oxide layer to be flush with the upper surface of the isolation material layer in the shallow groove, and the oxide layer and the isolation material layer flush with the oxide layer in the shallow groove are removed to form the shallow groove isolation structure. The invention has a flat surface after removing the nitride layer, and the flat surface can avoid transitional etching to the edge of the isolation material layer in the shallow trench and avoid forming an edge groove at the top edge of the shallow trench isolation structure when removing the oxide layer, thereby improving the performance of the device.

Inventors

• LI FEI
• Dong Zongtou

Assignees

• 合肥晶合集成电路股份有限公司

Dates

Publication Date

20260512

Application Date

20260416

Claims (10)

1. 1. A method of fabricating a semiconductor device, comprising the steps of: providing a substrate, forming an oxide layer and a nitride layer on the substrate, etching the nitride layer, the oxide layer and the substrate with partial thickness to form a shallow trench, and forming an isolation material layer which fills the shallow trench and covers the nitride layer; planarizing the isolation material layer to a remaining portion of the thickness of the isolation material layer over the nitride layer; removing the remaining isolation material layer on the nitride layer and the nitride layer such that an upper surface of the oxide layer is flush with an upper surface of the isolation material layer in the shallow trench, and And removing the oxide layer and the isolation material layer which is flush with the oxide layer in the shallow trench to form a shallow trench isolation structure.
2. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the isolation material layer is planarized by a chemical mechanical polishing process or a wet etching process.
3. 3. The method of manufacturing a semiconductor device according to claim 1, wherein a thickness of the isolation material layer remaining on the nitride layer after planarization is 200 a to 500 a.
4. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the isolation material layer and the nitride layer remaining on the nitride layer are removed by a dry etching process.
5. 5. The method of manufacturing a semiconductor device according to claim 4, wherein in the dry etching process, an etching selectivity ratio of the isolation material layer to the nitride layer is 1:1.
6. 6. The method of manufacturing a semiconductor device according to claim 1, wherein the oxide layer and the isolation material layer in the shallow trench, which is flush with the oxide layer, are removed by a wet etching process.
7. 7. The method of manufacturing a semiconductor device according to claim 6, wherein the etching solution used in the wet etching process comprises dilute hydrofluoric acid.
8. 8. The method for manufacturing a semiconductor device according to any one of claims 1 to 7, further comprising, before forming an oxide layer over the substrate, forming a barrier layer over the substrate, the oxide layer being formed over the barrier layer; and removing the barrier layer after removing the oxide layer.
9. 9. The method of manufacturing a semiconductor device according to claim 8, wherein the material of the barrier layer comprises spin-on carbon, and wherein the barrier layer is removed by oxygen plasma.
10. 10. A semiconductor device manufactured by the method of any one of claims 1 to 9.

Description

Semiconductor device and method for manufacturing the same Technical Field The present invention relates to the field of integrated circuits, and more particularly, to a semiconductor device and a method for fabricating the same. Background In the integrated circuit manufacturing process, the shallow trench isolation (Shallow Trench Isolation, STI) structure gradually replaces the local field oxidation process due to the advantages of having a planarized surface, being able to provide a smaller isolation dimension, and the like, and becomes the mainstream isolation process. In the manufacturing process of the shallow trench isolation structure, firstly, an oxide layer and a nitride layer are formed on a substrate, the nitride layer, the oxide layer and the substrate are etched to form a shallow trench, then an isolation material is formed, the isolation material fills the shallow trench and covers the nitride layer, then the isolation material is planarized until the nitride layer is exposed, and then the nitride layer and the oxide layer are removed. However, during the removal of the oxide layer, a side trench (divot) is typically formed at the top edge of the shallow trench isolation structure, resulting in uneven deposition of the subsequent thin film, which affects device performance. And as advanced process nodes advance, the edge grooves are more sensitive. Disclosure of Invention The invention aims to provide a semiconductor device and a manufacturing method thereof, which can avoid generating side grooves and improve the performance of the device. In order to solve the above technical problem, according to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising the steps of: providing a substrate, forming an oxide layer and a nitride layer on the substrate, etching the nitride layer, the oxide layer and the substrate with partial thickness to form a shallow trench, and forming an isolation material layer which fills the shallow trench and covers the nitride layer; planarizing the isolation material layer to a remaining portion of the thickness of the isolation material layer over the nitride layer; removing the remaining isolation material layer on the nitride layer and the nitride layer such that an upper surface of the oxide layer is flush with an upper surface of the isolation material layer in the shallow trench, and And removing the oxide layer and the isolation material layer which is flush with the oxide layer in the shallow trench to form a shallow trench isolation structure. Optionally, a chemical mechanical polishing process or a wet etching process is used to planarize the isolation material layer. Optionally, after planarization, the thickness of the isolation material layer remaining on the nitride layer is 200 a to 500 a. Optionally, a dry etching process is used to remove the isolation material layer and the nitride layer remaining on the nitride layer. Optionally, in the dry etching process, an etching selection ratio of the isolation material layer to the nitride layer is 1:1. Optionally, a wet etching process is used to remove the oxide layer and the isolation material layer in the shallow trench and flush with the oxide layer. Optionally, the etching solution adopted by the wet etching process comprises diluted hydrofluoric acid. Optionally, before forming the oxide layer on the substrate, forming a barrier layer on the substrate, wherein the oxide layer is formed on the barrier layer; and removing the barrier layer after removing the oxide layer. Optionally, the material of the barrier layer comprises spin-on carbon, and oxygen plasma is used to remove the barrier layer. In order to solve the above technical problem, according to a second aspect of the present invention, there is provided a semiconductor device manufactured by the manufacturing method of the semiconductor device as described above. In summary, in the semiconductor device and the method for manufacturing the same provided by the invention, a substrate is provided, an oxide layer and a nitride layer are formed on the substrate, a shallow trench is formed by etching the nitride layer, the oxide layer and a part of the substrate, an isolation material layer is formed to fill the shallow trench and cover the nitride layer, then the isolation material layer is planarized to the isolation material layer with the remaining thickness on the nitride layer, then the remaining isolation material layer and the nitride layer on the nitride layer are removed so that the upper surface of the oxide layer is flush with the upper surface of the isolation material layer in the shallow trench, and then the isolation material layer flush with the oxide layer in the shallow trench and the oxide layer are removed to form a shallow trench isolation structure. The unexpected effect of the present invention is that planarizing the isolation material layer to the thickness of