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Etching solution for stably etching titanium nitride

A titanium nitride and etching solution technology, applied in the field of etching solution for titanium nitride films, can solve the problems of high fluoride ion activity and high difficulty in inhibiting corrosion of the underlying metal layer, achieve high etching selectivity ratio, ensure etching rate, low Effect of Etch Rate

Pending Publication Date: 2022-04-15
湖北兴福电子材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] As a wet etching method for TiN hard mask, the wet etching solution used contains fluorine source, which will cause irreversible etching on the silicon substrate while removing titanium nitride, and the activity of fluorine ions is high, so it is difficult to inhibit the corrosion of the underlying metal layer. high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Said Example 1 only contains hydrogen peroxide and sulfuric acid, and the volume ratio of sulfuric acid to hydrogen peroxide is 6:1.

[0029] Etch the titanium nitride on the silicon substrate with the etching solution configured according to the above ratio at 75°C (cut the titanium nitride sheet into regular squares with a size of 2*2cm), and use tetrafluorostirrer for etching. Stirring, the stirring rate is 200r / min. In order to avoid the inaccurate test of titanium nitride due to oxidation in the natural environment, the titanium nitride test piece was first cleaned in the etching solution for 10 seconds to remove the surface oxide layer, and the titanium nitride test piece was tested by ellipsometry to obtain the titanium nitride test piece. The initial thickness of the sheet is 565.45 Å. Finally, put the titanium nitride test piece into the etching solution to etch for 120s, clean it and dry it with nitrogen gas, and use an ellipsometer for in-situ detection, and...

Embodiment 2

[0033] Said Example 2 contains hydrogen peroxide, sulfuric acid and ammonium persulfate, the volume ratio of sulfuric acid and hydrogen peroxide is 6:1, and the mass content of 3-(2,2,2-trifluoroethoxy)pyridin-2-amine is 0.2%, 2,2 bipyridyl 0.2%, ammonium persulfate mass content 0.1%.

[0034] According to the method of Example 1, the titanium nitride on the silicon substrate is etched. The thickness of titanium nitride before etching is 567.18Å, and the thickness of titanium nitride is 428.72Å after etching at 75°C for 120s. The etching rate of titanium oxide is 69.23Å / min.

[0035] According to the above etching method, the etching solution configured in the above ratio was used to etch the metal tungsten on the silicon substrate at 75°C. The thickness of the metal tungsten before etching was 882.47 Å, and the thickness of the metal tungsten after etching was 852.41 Å. The etching of metal tungsten The rate is 15.03Å / min.

[0036] The etch selectivity ratio of titanium nit...

Embodiment 3

[0038] In Example 3, the volume ratio of sulfuric acid to hydrogen peroxide is 6: the mass content of 1,3-(2,2,2-trifluoroethoxy)pyridin-2-amine is 0.2%, 2,2 bipyridine is 0.2%, and the The mass content of ammonium sulfate is 0.2%.

[0039] According to the method of Example 1, the titanium nitride on the silicon substrate is etched. The thickness of titanium nitride before etching is 567.65 Å, and the thickness of titanium nitride is 407.87 Å after etching at 75°C for 120s. The etch rate of titanium oxide is 79.89 Å / min.

[0040] According to the above etching method, the etching solution configured in the above ratio was used to etch the metal tungsten on the silicon substrate at 75 ° C. The thickness of the metal tungsten before etching was 878.56 Å, and the thickness of the metal tungsten after etching was 847.22 Å. The etching of metal tungsten The rate is 15.67 Å / min.

[0041]The etching selectivity ratio of titanium nitride to metal tungsten is 5.09.

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Abstract

The invention discloses an etching solution for stably etching titanium nitride, which comprises an oxidizing agent, sulfuric acid, a chelating agent, a corrosion inhibitor and a surfactant, and is used for etching films such as titanium nitride and the like under a stirring condition. The etching solution can quickly remove titanium nitride, and has a relatively low etching rate on metals such as tungsten, copper, cobalt and the like and compounds thereof, and low-k dielectric materials, and the etching rate does not fluctuate along with the change of etching time. The pH regulator sorbic acid and the like in the etching solution stabilize the pH of the etching solution, so that the influence on the etching rate and stability of titanium nitride and metal tungsten due to the fluctuation of the pH of the etching solution caused by hydroxyl released by titanium nitride and tungsten in the etching process is avoided; the surface active agent polyacrylamide changes the viscosity, the surface tension and the like of the etching liquid, the corrosion inhibitor protects the metal tungsten, stirring is carried out during etching, substance exchange of reactants between the surface of a wafer and the solution can be increased, and the etching selection ratio of titanium nitride to thin films such as the metal tungsten is ensured.

Description

technical field [0001] The invention relates to the processing of semiconductor substrates formed with titanium nitride films, tungsten, copper, cobalt, etc. and their compounds, and low-k dielectric material films, and mainly relates to etching solutions for titanium nitride films. Background technique [0002] Photoresist masks are commonly used in the semiconductor industry to pattern materials such as semiconductors or dielectrics. In one application, photoresist masks are used in a dual damascene process to form interconnects in back-end metallization of microelectronic devices. The dual damascene process includes forming a photoresist mask on a low-k dielectric layer overlying a metal conductor layer, such as a copper layer. The low-k dielectric layer is then etched according to the photoresist mask to form vias and / or trenches exposing the metal conductor layer. [0003] As microelectronic device dimensions decrease, achieving critical dimensions for vias and trench...

Claims

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Application Information

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IPC IPC(8): C09K13/06
Inventor 王书萍冯凯贺兆波张庭尹印万杨阳钟昌东李鑫
Owner 湖北兴福电子材料股份有限公司
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