KR102700158B1 - Etchant composition for titanium nitride layer - Google Patents

Abstract

The etchant composition of a metal nitride film according to the present invention is a metal nitride film etchant composition, characterized in that the composition comprises 0.3 to 10 wt% of a peroxide; 0.001 to 5 wt% of at least one selected from an organic acid and an organic acid salt; and a balance of water, based on the total weight% of the composition.
The etchant composition of the above metal nitride film has the effect of improving the TiN/W etching selectivity by including at least one selected from a peroxide, an organic acid, and an organic acid salt and water in a specific content.

Description

{ETCHANT COMPOSITION FOR TITANIUM NITRIDE LAYER}

The present invention relates to an etching composition for a metal nitride film.

Titanium nitride (TiN), a titanium-based metal, is used as a base layer or cap layer for precious metals, aluminum (Al), and copper (Cu) wiring in semiconductor devices, liquid crystal displays, micro electro mechanical systems (MEMS) devices, and printed wiring boards. It is also sometimes used as a barrier metal or gate metal in semiconductor devices.

Tungsten or tungsten-based metals together with the above titanium nitride or titanium nitride-based metals are used in liquid crystal displays, gate electrodes of thin film transistors of semiconductor devices, wiring, barrier layers, or filling of contact holes and via holes. In addition, it is also used as a tungsten heater in the field of microelectronic control technology.

In particular, a nitride metal film such as titanium nitride acts as a barrier layer to suppress etching from the etchant composition and prevent the underlying material from being etched. Therefore, it is difficult to etch a nitride metal film such as titanium nitride with a generally known etchant, so a method of removing it using a chemical mechanical polishing (CMP) method that combines the chemical properties of the etchant and the physical effect of polishing is generally used.

However, the chemical mechanical polishing method is inefficient because the process is complex, the application of the process is limited, there is a high possibility of other contamination occurring, and the cost is higher than that of a general wet process.

Korean Patent Publication No. 10-1587758 discloses a TiN film etchant composition comprising (A) 75 to 95 wt% of at least one selected from sulfuric acid and alkyl sulfonic acid, (B) 0.3 to 10 wt% of peroxide, (C) 1 to 30,000 ppm of inorganic ammonium salt, and (D) the remainder of water, and a method for forming a metal wiring using the etching composition.

However, the above prior literature contains inorganic ammonium salts and it can be seen that the TiN/W etching selectivity is significantly low.

Republic of Korea Patent No. 10-1587758 (January 15, 2016, Dongwoo Finechem Co., Ltd.)

The present invention is intended to solve the above problems, and the purpose of the present invention is to provide an etchant composition for a metal nitride film capable of improving the TiN/W etching selectivity by including a specific content of at least one selected from a peroxide, an organic acid, and an organic acid salt and water.

In order to achieve the above object, the etchant composition of a metal nitride film according to the present invention is a metal nitride film etchant composition, characterized in that the composition comprises 0.3 to 10 wt% of a peroxide; 0.001 to 5 wt% of at least one selected from an organic acid and an organic acid salt; and a balance of water, based on the total weight% of the composition.

As described above, the etchant composition for a metal nitride film according to the present invention has the effect of improving the TiN/W etching selectivity by including at least one selected from a peroxide, an organic acid, and an organic acid salt, and water, each in a specific content.

The metal nitride film etchant composition according to the present invention is characterized by comprising 0.3 to 10 wt% of a peroxide; 0.001 to 5 wt% of at least one selected from an organic acid and an organic acid salt; and a balance of water.

In addition, the metal nitride film etchant composition according to the present invention may further include 75 to 95 wt% of at least one selected from sulfuric acid and alkyl sulfonic acid.

The above metal nitride film etchant composition can be usefully used for selective etching of a metal nitride film in the presence of a metal film or metal wiring containing tungsten (W).

At this time, it is preferable that the etchant composition of the metal nitride film according to the present invention has a TiN/W etching selectivity of 11 or more. At this time, since the etching speed of W is 11 times or more faster than the etching speed of TiN, it has a characteristic suitable for a semiconductor wiring process that requires high-selectivity etching of TiN/W.

peroxide

The above peroxide increases the etching rate of the metal nitride film and oxidizes the tungsten film to control the etching rate of the tungsten film as required in the process.

The above peroxide _may be selected from hydrogen peroxide ( _H2O2 ), tert-butyl hydroperoxide, lauroyl peroxide, tert-butyl peracetate, tert-butyl peroxybenzoate, 2-butane peroxide, tert-butyl methyl ethyl ketone peroxide, benzoyl peroxide, dicumyl peroxide, and the like, and these may be used singly or in a combination of two or more.

It is preferable that the above peroxide be included in an amount of 0.3 to 10 wt%, and more preferably in an amount of 1 to 5 wt%, based on the total weight of the composition.

If the peroxide is included in an amount less than the above range, the etching speed of the metal nitride film may become too slow, which may cause problems in terms of process yield, and if the peroxide is included in an amount greater than the above range, selective etching of the metal nitride film may become difficult.

Organic acids and Organic acid salt

The above organic acids and organic acid salts play a role in preventing oxidation and etching of tungsten by sulfuric acid and peroxide, thereby lowering the etching rate of tungsten. Therefore, the etching selectivity of TiN/W can be increased.

It is preferable to contain at least one organic acid and organic acid salt selected from citric acid, malic acid, oxalic acid, ammonium acetate, and ammonium formate in an amount of 0.001 to 5 wt%, more preferably 0.005 to 3 wt%.

If the organic acid or organic acid ammonium salt is included in amounts below the above range, the etching rate of tungsten cannot be reduced, and if the organic acid or organic acid ammonium salt exceeds the above range, it may cause particle defects by recrystallization during single tool processing or may cause a dangerous process due to a rapid reaction with sulfuric acid and alkyl sulfonic acid.

water

The above water preferably has a weight ratio of at least one component selected from sulfuric acid and alkyl sulfonic acid and a peroxide component of 100:0.32 to 100:6.0, more preferably 100:2 to 100:4. If the water is out of the above range, the TiN/W etching selectivity cannot be implemented as 11 or more, or the etching speed of TiN becomes too slow, which increases the process time and may adversely affect the process throughput.

Sulfuric acid and Alkyl sulfonic acid

At least one selected from sulfuric acid and alkyl sulfonic acid can etch a metal oxidized by a peroxide, and can perform the function of controlling the etching amount and selectivity of a TiN film and a tungsten film.

The above alkyl sulfonic acid can be selected from methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, and the like, and these can be used singly or in a combination of two or more.

It is preferable that at least one selected from the above sulfuric acid and alkylsulfonic acid is included in an amount of 75 to 95 wt% with respect to 100 wt% of the etchant composition for the metal nitride film.

If at least one selected from the above sulfuric acid and alkyl sulfonic acid is included in an amount of less than 75 wt%, the content of peroxide and water relatively increases, which causes a problem in that the etching rate of tungsten becomes faster while the etching selectivity of TiN/W becomes lower. In addition, if at least one selected from the above sulfuric acid and alkyl sulfonic acid exceeds 95 wt%, the etching rate of TiN becomes too slow, which may cause a problem in terms of process yield.

The etchant composition for a metal nitride film according to the present invention comprises 75 to 95 wt% of at least one selected from sulfuric acid and alkylsulfonic acid; 0.3 to 10 wt% of a peroxide; 0.001 to 5 wt% of at least one selected from organic acids and organic acid salts; and a water balance, thereby having the effect of improving the TiN/W etching selectivity to 11 or more.

A method for producing a metal nitride film etchant composition according to the present invention may include a step of forming a first mixture by mixing a peroxide; at least one selected from an organic acid and an organic acid salt; and water; and a step of obtaining a second mixture by mixing at least one selected from sulfuric acid and an alkyl sulfonic acid with the first mixture.

The metal nitride film etchant composition manufactured above can be obtained by mixing, based on the total weight % of the composition, 0.3 to 10 wt% of the first mixture, 0.001 to 5 wt% of at least one selected from organic acids and organic acid salts, and the remainder of water, and the second mixing step can be obtained by mixing 75 to 95 wt% of at least one selected from sulfuric acid and alkyl sulfonic acid.

At this time, it is preferable that the weight ratio of at least one component selected from the sulfuric acid and alkylsulfonic acid and the peroxide component is 100:0.3 to 100:10.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended to explain the present invention more specifically, and the scope of the present invention is not limited by the following examples. The following examples can be appropriately modified and changed by those skilled in the art within the scope of the present invention. In addition, "%" and "part" indicating the content below are based on weight unless specifically stated.

Example 1 to 10 and Comparative example 1 to 7

An etchant composition for a metal nitride film containing the components and composition (weight %) of Table 1 below was prepared. At this time, in the examples and comparative examples below, 31% sulfuric acid and 96% sulfuric acid were used as sulfuric acid and peroxide.

(weight%) Sulfuric acid/alkyl sulfonic acid Fruit/Peroxide Organic acid/organic acid salt DIW type Content type Content type Content Content Example 1 Sulfuric acid 88.13 fruit tree 2.01 Citric acid 0.52 Remaining amount Example 2 Sulfuric acid 88.13 fruit tree 2.01 Malsan 0.52 Remaining amount Example 3 Sulfuric acid 88.13 fruit tree 2.01 Oxalic acid 0.52 Remaining amount Example 4 Sulfuric acid 87.97 fruit tree 2.60 Ammonium acetate 0.1 Remaining amount Example 5 Sulfuric acid 87.97 fruit tree 2.60 Ammonium formate 0.1 Remaining amount Example 6 Sulfuric acid 82 fruit tree 5 Ammonium acetate 0.1 Remaining amount Example 7 Sulfuric acid 79.53 fruit tree 2.60 Ammonium acetate 5 Remaining amount Example 8 Sulfuric acid 95 fruit tree 0.3 Ammonium acetate 0.01 Remaining amount Example 9 MSA 87.97 TBHP 2.60 Ammonium acetate 0.1 Remaining amount Example 10 MSA 87.97 MEKP 2.60 Ammonium acetate 0.1 Remaining amount Comparative Example 1 Sulfuric acid 88.13 fruit tree 2.01 - - Remaining amount Comparative Example 2 MSA 88.13 TBHP 2.01 - - Remaining amount Comparative Example 3 Sulfuric acid 82.13 fruit tree 2.01 Citric acid 6 Remaining amount Comparative Example 4 Sulfuric acid 78.53 fruit tree 2.60 Ammonium acetate 6 Remaining amount Comparative Example 5 Sulfuric acid 96 fruit tree - Citric acid 0.01 Remaining amount Comparative Example 6 Sulfuric acid 87.5 fruit tree 2.5 Ammonium sulfate 0.01 Remaining amount Comparative Example 7 MSA 87.5 TBHP 2.5 Ammonium sulfate 0.01 Remaining amount MSA: Methanesulfonic acid
TBHP: tert-butyl hydroperoxide
MEKP: Methyl ethyl ketone peroxide

Experimental example : Etching Characteristic Evaluation

The substrates on which TiN, W, SiNx, SiOx, poly Si, and HfOx films were formed were immersed in the compositions for etching metal nitride films of Examples 1 to 10 and Comparative Examples 1 to 7 at 75°C for 5 minutes.

The etching rate for the film quality of each substrate was determined by measuring the change in film thickness using an ellipsometer (SE-MG-1000), and the results are shown in Table 2 below. Also, the unit of the numerical values described below is Å/min.

Etching amount of TiN Etching amount of W TiN/W etching selectivity Example 1 46.24 3.8 12.2 Example 2 49.48 3.9 12.7 Example 3 39.25 3.5 11.2 Example 4 42.25 3.2 13.2 Example 5 41.58 3.5 11.9 Example 6 24.54 2.2 11.2 Example 7 31.21 2.8 11.1 Example 8 16.58 1.5 11.1 Example 9 17.9 1.4 12.8 Example 10 18.2 1.5 12.1 Comparative Example 1 44.2 8.3 5.4 Comparative Example 2 15.8 2.5 6.3 Comparative Example 3 - - - Comparative Example 4 - - - Comparative Example 5 2.1 0.8 2.6 Comparative Example 6 44.5 5.2 8.6 Comparative Example 7 13.2 1.6 8.3

Referring to Table 2 above, it can be seen that in the cases of Examples 1 to 10, while maintaining excellent etching performance for a titanium nitride film, the etching amount of a tungsten film is suppressed, and as a result, the etching selectivity of TiN/W is 11 or higher. On the other hand, in the cases of Comparative Examples 1 to 7 that do not satisfy the above range, it can be seen that the desired etching selectivity of TiN/W is not achieved.

Claims (10)

As a metal nitride film etchant composition, the composition comprises:
0.3 to 10 wt% peroxide;
0.001 to 5 wt% of at least one selected from malic acid, oxalic acid, ammonium acetate and ammonium formate; and
Includes water remaining,
A metal nitride film etchant composition characterized in that the TiN/W etching selectivity is 11 or more. In the first paragraph,
For 100 wt% of the above metal nitride film etching solution composition,
A metal nitride film etching composition characterized by further comprising 75 to 95 wt% of at least one selected from sulfuric acid and alkyl sulfonic acid. In the second paragraph,
A metal nitride film etching composition characterized in that the weight ratio of at least one component selected from the above sulfuric acid and alkyl sulfonic acid and the above peroxide component is 100:0.3 to 100:10. In the second paragraph,
The above alkyl sulfonic acid is
A metal nitride film etchant composition characterized by comprising at least one selected from the group consisting of methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and butanesulfonic acid. In the first paragraph,
A metal _nitride film etchant composition characterized in that the peroxide is at least one selected from the group consisting of hydrogen peroxide ( _H2O2 ), tert-butyl hydroperoxide, lauroyl peroxide, tert-butyl peracetate, tert-butyl peroxybenzoate, 2-butane peroxide, tert-butyl methyl ethyl ketone peroxide, benzoyl peroxide, and dicomyl peroxide. delete delete A step of forming a first mixture by mixing at least one selected from peroxide; malic acid, oxalic acid, ammonium acetate and ammonium formate; and water; and
A step of obtaining a second mixture by mixing at least one selected from sulfuric acid and alkylsulfonic acid into the first mixture;
A method for producing a metal nitride film etchant composition, characterized in that the TiN/W etching selectivity of the second mixture is 11 or more. In Article 8,
The metal nitride film etching composition manufactured above is, based on the total weight % of the composition,
The first mixture comprises 0.3 to 10 wt% of the peroxide; 0.001 to 5 wt% of at least one selected from the organic acid and organic acid salt; and the remainder of water.
A method for producing a metal nitride film etching composition, characterized in that the second mixture contains 75 to 95 wt% of at least one selected from the group consisting of sulfuric acid and alkyl sulfonic acid. In Article 8,
A method for producing a metal nitride film etching composition, characterized in that the weight ratio of at least one component selected from the above sulfuric acid and alkyl sulfonic acid and the above peroxide component is 100:0.3 to 100:10.