Semiconductor structure and method for forming semiconductor structure

Patent metadata

Field	Value
Publication number	US-2023386892-A1
Application number	US-202318167024-A
Country	US
Kind code	A1
Filing date	Feb 9, 2023
Priority date	May 24, 2022
Publication date	Nov 30, 2023
Grant date	—

Abstract

A semiconductor structure is formed by: providing a substrate, wherein an insulation layer, an initial metal conductive layer, an initial sacrifice layer, and a mask layer stacking in sequence are formed on the substrate, wherein the initial sacrifice layer includes a metal oxide layer; forming a metal conductive layer and a sacrifice layer atop the metal conductive layer by etching the initial sacrifice layer and the initial metal conductive layer using an oxygen source gas as an etching gas based on a patterned mask layer; removing the patterned mask layer by performing an ashing process using the oxygen source gas as the etching gas; removing the sacrifice layer as well as a by-product formed during the etching and the ashing process and exposing the metal conductive layer by performing a corrosion process using an alkaline corrosion solution; and forming an isolation structure between adjacent metal conductive layers.

First claim

What is claimed is:

1 . A method for forming a semiconductor structure, comprising:
providing a substrate, wherein an insulation layer, an initial metal conductive layer, an initial sacrifice layer, and a mask layer stacking in sequence are formed on the substrate, wherein the initial sacrifice layer comprises a metal oxide layer; forming a metal conductive layer and a sacrifice layer atop the metal conductive layer by etching the initial sacrifice layer and the initial metal conductive layer using an oxygen source gas as an etching gas based on a patterned mask layer; removing the patterned mask layer by performing an ashing process using the oxygen source gas as the etching gas; removing the sacrifice layer as well as a by-product formed during the etching and the ashing process and exposing the metal conductive layer by performing a corrosion process using an alkaline corrosion solution; and forming an isolation structure between adjacent metal conductive layers.

2 . The method of claim 1 , wherein the initial sacrifice layer is formed by:
performing a planarization process on the initial metal conductive layer; and forming the initial sacrifice layer atop the initial metal conductive layer by oxidizing the initial metal conductive layer using oxygen plasma, wherein the initial metal conductive layer and the metal conductive layer are made of a material comprising tungsten, wherein the initial sacrifice layer is made of a material comprising tungsten oxide.

3 . The method of claim 1 , wherein the mask layer comprises an amorphous carbon layer, wherein forming the metal conductive layer and the sacrifice layer atop the metal conductive layer by etching the initial sacrifice layer and the initial metal conductive layer using the oxygen source gas as the etching gas based on the patterned mask layer comprises:
forming a patterned amorphous carbon layer atop the initial sacrifice layer; and forming the metal conductive layer and the sacrifice layer atop the metal conductive layer by etching the initial sacrifice layer and the initial metal conductive layer via in-situ oxygen plasma etching based on the patterned amorphous carbon layer.

4 . The method of claim 3 , wherein removing the patterned mask layer by performing the ashing process using the oxygen source gas as the etching gas comprises:
removing the patterned amorphous carbon layer by performing the ashing process using oxygen plasma.

5 . The method of claim 1 , wherein the by-product formed during the etching and the ashing process comprises an oxide of tungsten.

6 . The method of claim 1 , wherein removing the sacrifice layer as well as the by-product formed during the etching and the ashing process and exposing the metal conductive layer by performing the corrosion process using the alkaline corrosion solution comprises:
removing a natural oxide on the sacrifice layer and exposing the sacrifice layer as well as the by-product formed during the etching and the ashing process by pretreating a surface of the sacrifice layer; removing the sacrifice layer as well as the by-product formed during the etching and the ashing process using the alkaline corrosion solution, and exposing the metal conductive layer; removing the alkaline corrosion solution remaining atop the metal conductive layer; and drying the metal conductive layer.

7 . The method of claim 1 , wherein the alkaline corrosion solution comprises an Ammonia Diw Mixture (ADM), wherein a volume ratio of ammonia to deionized water in the ADM ranges from 5:1 to 1000:1.

8 . The method of claim 6 , wherein the metal conductive layer is dried using isopropyl alcohol and nitrogen.

9 . The method of claim 1 , wherein forming the isolation structure between the adjacent metal conductive layers comprises:
forming the isolation structure by sequentially forming a first dielectric layer and a second dielectric layer between the adjacent metal conductive layers.

10 . The method of claim 1 , wherein an initial barrier layer located between the insulation layer and the initial metal conductive layer is also formed on the substrate,
wherein forming the metal conductive layer and the sacrifice layer atop the metal conductive layer by etching the initial sacrifice layer and the initial metal conductive layer using the oxygen source gas as the etching gas based on the patterned mask layer comprises: forming a groove by etching the initial sacrifice layer, the initial metal conductive layer, and the initial barrier layer using the oxygen source gas as the etching gas based on the patterned mask layer, and forming, on both sides of the groove, a barrier layer, the metal conductive layer, and the sacrifice layer stacking in sequence, wherein forming the isolation structure between the adjacent metal conductive layers comprises: forming the isolation structure in the groove.

11 . The method of claim 2 , wherein the initial sacrifice layer is formed atop the initial metal conductive layer using a process gas comprising: oxygen, a hydrogen nitrogen mixture, nitrogen, and argon, wherein the process gas flows in at a flow rate ranging from 100 standard ml/min to 15000 standard ml/min, wherein a pressure of a region where the oxygen plasma are produced ranges from 10 mtorr to 10000 mtorr, wherein a radio frequency power ranges from 10 W to 10000 W.

12 . The method of claim 2 , wherein the by-product formed during the etching and the ashing process comprises an oxide of tungsten.

13 . The method of claim 2 , wherein removing the sacrifice layer as well as the by-product formed during the etching and the ashing process and exposing the metal conductive layer by performing the corrosion process using the alkaline corrosion solution comprises:
removing a natural oxide on the sacrifice layer and exposing the sacrifice layer as well as the by-product formed during the etching and the ashing process by pretreating a surface of the sacrifice layer; removing the sacrifice layer as well as the by-product formed during the etching and the ashing process using the alkaline corrosion solution, and exposing the metal conductive layer; removing the alkaline corrosion solution remaining atop the metal conductive layer; and drying the metal conductive layer.

14 . The method of claim 3 , wherein the by-product formed during the etching and the ashing process comprises an oxide of tungsten.

15 . The method of claim 3 , wherein removing the sacrifice layer as well as the by-product formed during the etching and the ashing process and exposing the metal conductive layer by performing the corrosion process using the alkaline corrosion solution comprises:
removing a natural oxide on the sacrifice layer and exposing the sacrifice layer as well as the by-product formed during the etching and the ashing process by pretreating a surface of the sacrifice layer; removing the sacrifice layer as well as the by-product formed during the etching and the ashing process using the alkaline corrosion solution, and exposing the metal conductive layer; removing the alkaline corrosion solution remaining atop the metal conductive layer; and drying the metal conductive layer.

16 . The method of claim 4 , wherein the by-product formed during the etching and the ashing process comprises an oxide of tungsten.

17 . A semiconductor structure, formed via the method of claim 1 , the semiconductor structure comprising:
the substrate, wherein the insulation layer is formed on the substrate; the metal conductive layer located atop the insulation layer; and the isolation st

Assignees

• Changxin Memory Tech Inc

Inventors

• Wang Peimeng
• Xi Ning
• Bai Shijie

Classifications

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• H10P76/405

  characterised by their composition, e.g. multilayer masks · CPC title

• H10P70/27

  during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers · CPC title

• H10P50/283

  by chemical means · CPC title

• H10P14/61

  using masks · CPC title