KR102161019B1 - Composition for etching titanium nitrate layer-tungsten layer containing laminate, method for etching using the same and semiconductor device manufactured by using the same - Google Patents

Abstract

In the present invention, the etch selectivity of the titanium nitride film and the tungsten film can be maintained at about 1, there is no decrease in the etch rate even when used for a long time in a high temperature process, and an etching composition for a laminate of a titanium nitride film and a tungsten film having an excellent life time, A method of etching a laminate of a titanium nitride film and a tungsten film using the same, and a semiconductor device including the same are provided.

Description

Etching composition for a laminate of a titanium nitride layer and a tungsten layer, an etching method using the same, and a semiconductor device manufactured therefrom BACKGROUND OF THE INVENTION 1.

The present invention relates to an etching composition for a laminate of a titanium nitride film and a tungsten film, an etching method using the same, and a semiconductor device manufactured therefrom. More specifically, the etching rate of the titanium nitride film and the tungsten film is the same in the semiconductor device manufacturing process. , An etching composition for a laminate of a titanium nitride film and a tungsten film, which maintains the etch selectivity 1 of the tungsten film with respect to the titanium nitride film and does not decrease the etch rate even when used for a long time in a high temperature process, and the laminate of the titanium nitride film and the tungsten film using the same. The present invention relates to an etching method and a semiconductor device including a laminate of a titanium nitride film and a tungsten film etched therefrom.

In order to etch the titanium nitride film (TiN) and the tungsten film (W) at the same rate in the wet process of a semiconductor integrated circuit, a conventional mixed solution of phosphoric acid, nitric acid, and acetic acid was used as the etching composition. During wet etching using the above etching composition, the room temperature process can maintain the selectivity of the tungsten layer compared to the titanium nitride layer, and there is no problem such as a decrease in the etching rate even when used for a long time. However, compared to the high-temperature process, the etching rate is significantly lower, which is not preferable in terms of time and economy. In addition, in order to wet-etch the titanium nitride film and the tungsten film at the same rate, a high-temperature process is preferable. However, in the conventional etching composition, when wet etching is performed at a high process temperature, acetic acid and nitric acid in the etching composition evaporate and tungsten compared to the titanium nitride film. There is a problem in that the selectivity of the film cannot be kept constant, and the etching rate is significantly reduced when used for a long time. In addition, due to such problems, there are many limitations in terms of time and economy because the conventional etching composition must be replaced with a new etching solution after one process.

Accordingly, the etching rate of the titanium nitride layer (TiN) and the tungsten layer (W) is the same in the manufacturing process of the semiconductor device, so that the etch selectivity of the tungsten layer to the titanium nitride layer is maintained, and the etching rate is reduced even when used for a long time in a high temperature process. Development of an etching composition without deterioration is required.

Japanese Publication No. 2008-536312 (released on September 4, 2008) Japanese Publication No. 2004-0315887 (published on November 11, 2004) Korea Publication No. 2013-0050829 (released on May 16, 2013)

Accordingly, an object of the present invention is to maintain the etching selectivity 1 of the tungsten layer to the titanium nitride layer by maintaining the same etching rate of the titanium nitride layer (TiN) and the tungsten layer (W) in the manufacturing process of a semiconductor device, and for a long time in a high temperature process. It is to provide an etching composition for a laminate of a titanium nitride film and a tungsten film, which does not decrease the etch rate even when used and has an improved life time.

Another object of the present invention is to provide a method of etching a laminate of a titanium nitride film and a tungsten film using the etching composition.

Another object of the present invention is to provide a semiconductor device including a laminate of a titanium nitride film and a tungsten film etched by the above etching method.

The etching composition for a laminate of a titanium nitride film and a tungsten film according to an embodiment of the present invention includes (a) 50 to 80% by weight of phosphoric acid, (b) 5 to 20% by weight of nitric acid, and (c) 0.01 to 10% by weight of an ammonium compound. % And (d) the balance of the solvent.

The (c) ammonium compounds include ammonium sulfate, ammonium persulfate, ammonium hydroxide, ammonium chloride, ammonium phosphate, ammonium nitrate, AN) and a mixture thereof may be selected from the group consisting of.

The etching composition includes periodic acid, iodic acid, ortho periodic acid, hypoiodous acid, chloric acid, percholic acid, and hypochlorous acid. Hypochlorous acid, chlorous acid, perbromic acid, bromic acid, bromous acid, methanesulfonic acid, para-toluenesulfonic acid ( Para-toluene sulfonic acid) Selected from the group consisting of ethanesulfonic acid, 1-Hexanesulfonic acid, 1-Octanesulfonic acid, Benzenesulfonic acid, and mixtures thereof It may further include a secondary oxidizing agent.

A method of etching a laminate of a titanium nitride film and a tungsten film according to another embodiment of the present invention includes etching the laminate of the titanium nitride film and the tungsten film using the above etching composition.

A semiconductor device according to another embodiment of the present invention includes a laminate of a titanium nitride film and a tungsten film, etched by the above etching method.

Other specific details of the embodiments of the present invention are included in the detailed description below.

The etching composition for a laminate of a titanium nitride film and a tungsten film according to the present invention has the same etch rate of the titanium nitride film (TiN) and the tungsten film (W) in the manufacturing process of the semiconductor device, so that the etching selectivity of the tungsten film to the titanium nitride film 1 is maintained and there is no decrease in etching rate even when used for a long time in a high temperature process, and has an improved life time.

1 is a graph showing the result of observing the change in the etching rate of a titanium nitride film (TiN) according to the exposure time of the etching composition at a high temperature of 70 ℃.
2 is a graph showing the result of observing the change in the etch rate of the tungsten film W according to the exposure time of the etching composition at a high temperature of 70°C.

Hereinafter, the present invention will be described in more detail.

In the present specification, when a portion such as a layer, a film, a region, or a substrate is said to be'on' another portion, this includes not only a case immediately above the other portion, but also a case where another portion is in the middle. On the other hand, when a part is said to be'right above' another part, it means that there is no other part in the middle. Conversely, when a part such as a layer, a film, a region, or a substrate is said to be'below' another part, this includes not only the case just below the other part, but also the case where another part is in the middle. On the other hand, when a part is said to be'right below' another part, it means that there is no other part in the middle.

The etching composition for a laminate of a titanium nitride (TiN) film and a tungsten (W) film according to an embodiment of the present invention includes (a) 50 to 80% by weight of phosphoric acid, (b) 5 to 20% by weight of nitric acid, (c) ammonium 0.01 to 10% by weight of the system compound and (d) the remainder of the solvent.

In the etching composition, (a) phosphoric acid serves to decompose titanium metal nitride and tungsten metal.

Such phosphoric acid may be included in an amount of 50 to 80% by weight based on the total weight of the etching composition. When the phosphoric acid content in the etching composition is less than 50% by weight, etching of the titanium nitride layer and the tungsten layer may be significantly reduced, and when the phosphoric acid content exceeds 80% by weight, there is a concern of overetching. The phosphoric acid may be preferably contained in an amount of 60 to 80% by weight based on the total weight of the etching composition in that a more excellent etching effect can be obtained without fear of overetching.

The (b) nitric acid reacts with the tungsten-based metal to form an oxide, and serves to increase the etching rate of the tungsten-based metal and the titanium-based metal. In addition, it plays a role of controlling the etch rate and stop ratio together with (a) phosphoric acid.

Such nitric acid may be included in an amount of 5 to 20% by weight based on the total weight of the etching composition. If the content of nitric acid in the etching composition is less than 5% by weight, the etching effect may be deteriorated, and if it exceeds 20% by weight, etching control may be difficult due to an excessive increase in the etching rate. In consideration of easy control of the etching rate and better etching effect, the nitric acid may preferably be included in an amount of 5 to 10% by weight based on the total weight of the etching composition.

In general, titanium (Ti) is well etched when it has high basicity. However, the conventional etching solution composition is difficult to apply to Ti because it is acidic, including nitric acid, phosphoric acid and acetic acid. On the other hand, by including the (c) ammonium-based compound in the etching composition, the oxidizing power of the oxidizing agent is maximized, thereby increasing the etching rate during the wet etching process and improving etching non-uniformity.

The (c) ammonium-based compound is a compound containing an ammonium cation, specifically, ammonium sulfate (APS), ammonium persulfate, ammonium hydroxide, and ammonium chloride (AC) , Ammonium phosphate (AP), ammonium nitrate (AN), and the like, and one of them alone or a mixture of two or more may be used.

The ammonium-based compound as described above may be included in an amount of 0.01 to 10% by weight based on the total weight of the etching composition. If the amount of the ammonium compound in the etching composition is less than 0.01% by weight, the effect of increasing the etching rate and improving the etching non-uniformity is insignificant. . In consideration of the easy control of the etch rate and the better effect of improving etch non-uniformity, the ammonium-based compound may preferably be contained in an amount of 0.1 to 1% by weight based on the total weight of the etching composition.

The etching composition may further include a solvent in an amount of the remainder in addition to the above components. The solvent may be water, but the present invention is not limited thereto.

In addition, the etching composition is a secondary oxidizing agent such as periodic acid, iodic acid, ortho periodic acid, hypoiodous acid, chloric acid, and perchloric acid. halogenated oxo acids such as percholic acid, hypochlorous acid, chlorous acid, perbromic acid, bromic acid, or bromous acid ; Methanesulfonic acid, Para-toluene sulfonic acid Ethanesulfonic acid, 1-Hexanesulfonic acid, 1-Octanesulfonic acid or benzene Sulfonic acid compounds such as benzenesulfonic acid; And it may further include those selected from the group consisting of a mixture thereof.

In addition, the etching composition may further add an alkaline compound or an acid other than the phosphoric acid and nitric acid as needed for pH adjustment.

The alkaline compound may be ammonia, an amine or tetraalkyl ammonium hydroxide, a nitrogen-containing heterocyclic compound, or the like. The acids other than the phosphoric acid and nitric acid include inorganic acids such as silicic acid, hydrofluoric acid, boric acid, hydrochloric acid, sulfuric acid, nitric acid, and perchloric acid, or organic acids such as carboxylic acid, organic phosphorous acid, and organic sulfonic acid.

In addition, the etching composition may further include a surfactant as necessary to remove the etched residue. As the surfactant, anionic surfactant, cationic surfactant, or nonionic surfactant may be used. Examples of the cationic surfactant include amines such as C ₈ H ₁₇ NH ₂ , and examples of the anionic surfactant include hydrocarbon-based carboxylic acids such as C ₈ H ₁₇ COOH, and C ₈ H ₁₇ SO ₃ H. Hydrocarbon-based sulfonic acids and fluorine-based carboxylic acids such as H(CF ₂ ) ₆ COOH, and the like. Examples of the nonionic surfactant include ethers such as polyoxyalkylene alkyl ethers.

The etching composition having the above-described configuration has the same etching rate for the titanium nitride (TiN) layer and the tungsten (W) layer when etching the stack of the titanium nitride (TiN) layer and the tungsten (W) layer in the manufacturing process of the semiconductor device. It maintains the etch selectivity 1 of the film, does not decrease the etch rate even when used for a long time in a high temperature process, and has an improved life time.

According to another embodiment of the present invention, a method of etching a laminate of a titanium nitride (TiN) layer and a tungsten (W) layer using the above etching composition is provided.

Specifically, the etching method includes forming a laminate by sequentially forming the titanium nitride film and a tungsten film on a substrate, and performing etching by adding the etching composition to the laminate, and after completion of the etching It may optionally further include removing the remaining etching composition.

The substrate may preferably be a semiconductor wafer, but the present invention is not limited thereto, and any substrate commonly used in the technical field of the present invention may be used.

The titanium nitride film and the tungsten film for the substrate may be formed according to a conventional method of forming a titanium nitride film and a tungsten metal film, and the order of forming the titanium nitride film and the tungsten film is not particularly limited.

In addition, the method of treating the etching composition for the laminate of the titanium nitride layer and the tungsten layer is not particularly limited, and may be, for example, coating, dipping, spraying or spraying, and in particular, there is little change in composition over time and etching A method of immersion (batch type device) or a method of spraying (sheet wafer type device), which has the advantage of small change in speed, can be preferably used.

The application temperature of the etching composition is not particularly limited, but may be specifically 60 to 80°C, and when the etching composition is applied within the temperature range, it may be more advantageous for simultaneous etching of the titanium nitride layer and the tungsten layer.

After completion of the etching process, a removal process using ultrapure water or the like for the remaining etching composition and a drying process on the etched laminate may be performed. The removal process and drying process may be performed according to a conventional method.

The etching method as described above can also be applied to a method of manufacturing a semiconductor device including a laminate of a titanium nitride layer and a tungsten layer.

Specifically, forming a tungsten film on the substrate; Forming a titanium nitride film on the tungsten film to form a titanium nitride film-tungsten film laminate; Forming an antireflection film on the titanium nitride film of the laminate; Forming a photoresist film on the antireflection film; Exposing and developing the photoresist layer to form a photoresist pattern exposing the antireflection layer; And etching the laminate of the antireflection layer and the titanium nitride layer-tungsten layer exposed by using the photoresist pattern as an etching mask using the above etching composition.

The etching composition described above is the same as described above, and the method of manufacturing the semiconductor device may be carried out according to a conventional method except for using the etching composition.

Accordingly, according to another embodiment of the present invention, a semiconductor device manufactured using the above-described etching method is provided.

At this time, the type of the semiconductor device is not particularly limited as long as it includes a laminate of a titanium nitride film and a tungsten film.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms, and is not limited to the embodiments described herein.

[Production Example: Preparation of etching composition]

As described in Table 1 below, the etching compositions of Example Preparation Example and Comparative Preparation Example were prepared while varying the formulation.

Composition of etching composition (% by weight) Phosphoric acid nitric acid Ammonium compound
APS Acetic acid water Preparation Example 1 65 15 One - Balance Preparation Example 2 65 14.7 0.1 - Balance Comparative Production Example 1 72 1.9 - 13.6 Balance

In Table 1, APS is ammonium persulfate.

[Test Example: Etching Characteristics Evaluation]

Etching was performed on the substrate on which the laminate of the titanium nitride film and the tungsten film was formed by using the etching composition prepared in the Example Preparation Example and Comparative Preparation Example under the conditions as described in Tables 2 and 3 below, and the etching rate and etching selectivity Was evaluated.

Specifically, the etching compositions prepared in Example Preparation Example and Comparative Preparation Example were placed in a beaker, respectively, and the etching composition was exposed at a temperature of 70°C. The substrate on which the titanium nitride layer and the tungsten layer were formed was immersed in the etching composition for 3 to 24 hours after exposure, and the etching rate and selectivity were measured according to the exposure time at 70° C. of the etching composition. The results are shown in Tables 2 and 3 below.

At this time, the etch rate was determined by measuring the thickness of the titanium nitride film and the tungsten film using an ellipsometric tree (Nano-View, SE-MG-1000; Ellipsometery), and the selectivity (TiN/W) was determined by Equation 1 below. Was calculated:

In Equation 1, A is the etching rate of the tungsten layer, B is the etching rate of the titanium nitride layer, and C is the selectivity ratio.

Etching composition evaluation Exposure time of etching composition
(time) Etching speed (Å/min) Selection ratio
(TiN/W) Titanium nitride film
(TiN) Tungsten film
(W) Example 1 Preparation Example 1 - 7.67 8.87 0.86 Example 2 " 3 7.04 8.50 0.83 Example 3 " 6 7.25 7.75 0.93 Example 4 " 9 6.80 7.21 0.94 Example 5 " 12 6.24 6.81 0.92 Example 6 " 15 6.34 6.64 0.95 Example 7 " 18 6.12 6.27 0.98 Example 8 " 21 6.02 5.84 1.03 Example 9 " 24 5.71 5.23 1.09 Example 10 Preparation Example 2 - 6.87 7.53 0.91 Example 11 " 3 6.85 7.48 0.92 Example 12 " 6 6.80 7.52 0.90 Example 13 " 9 6.81 7.55 0.90 Example 14 " 12 6.85 7.40 0.93 Example 15 " 15 6.48 6.92 0.94 Example 16 " 18 6.34 6.51 0.97 Example 17 " 21 6.02 5.74 1.05 Example 18 " 24 5.98 5.69 1.05

Etching composition evaluation Exposure time of etching composition
(time) Etching speed (Å/min) Selection ratio
(TiN/W) Titanium nitride film
(TiN) Tungsten film
(W) Comparative Example 1 Comparative Production Example 1 - 6.58 6.47 1.02 Comparative Example 2 " 3 6.67 6.36 1.05 Comparative Example 3 " 6 6.49 6.21 1.04 Comparative Example 4 " 9 5.32 4.59 1.16 Comparative Example 5 " 12 4.19 2.47 1.70 Comparative Example 6 " 15 4.13 2.34 1.76 Comparative Example 7 " 18 3.98 2.02 1.97 Comparative Example 8 " 21 4.01 1.92 2.09 Comparative Example 9 " 24 3.83 1.86 2.06

As shown in Tables 2 and 3, in the case of the etching composition of Comparative Preparation Example 1 used in Comparative Examples 1 to 9, the etching rate of the tungsten film was significantly lowered compared to the titanium nitride film from 6 hours after exposure, and the selectivity was side It also caused adverse effects. However, in the case of the etching compositions of Examples 1 and 2 used in Examples 1 to 9 and Examples 10 to 18, the etching rate of the titanium nitride film and the tungsten film hardly decreased until 24 hours after exposure. , The etch selectivity of the tungsten film compared to the titanium nitride film was also maintained around 1. From these results, it can be confirmed that the etching compositions of Examples 1 and 2 have an improved life time compared to the etching compositions of Comparative Preparation Examples.

The results of observing the change of the etching rate according to the exposure time of the etching composition are shown in FIGS. 1 and 2.

1 is a graph showing the etching rate of a titanium nitride (TiN) film according to the exposure time of the etching composition at a high temperature of 70°C, and FIG. 2 is a graph showing the etching rate of the tungsten (W) film according to the exposure time of the etching composition at a high temperature of 70°C. It is a graph showing the speed.

As shown in FIG. 1, the etching rate of the titanium nitride film rapidly decreased from 6 hours after the exposure time of the etching composition at a process temperature of 70°C in the etching composition of Comparative Preparation Example 1. However, in the case of the etching compositions of Preparation Examples 1 and 2, it can be seen that there is little change in the etching rate for the titanium nitride film until 24 hours after the etching composition is exposed.

On the other hand, in the case of the tungsten film, as shown in FIG. 2, the etching rate of the tungsten film rapidly decreased from 6 hours after the exposure of the etching composition at a process temperature of 70° C. as shown in FIG. 2. However, in the case of the etching compositions of Preparation Examples 1 and 2, it can be seen that there is little change in the etching rate for the tungsten layer until 24 hours after the etching composition is exposed.

These results show that in the case of the etching composition of Comparative Preparation Example 1, when exposed to the process temperature of 70°C, the etching rates of the titanium nitride layer and the tungsten layer rapidly increased from 6 hours after exposure to the etching composition due to evaporation of acetic acid and nitric acid in the etching composition. Deteriorated. However, the etching compositions of Examples 1 and 2 have improved etching rates for the titanium nitride layer and the tungsten layer compared to the etching composition of Comparative Preparation Example 1, and there is no decrease in the etching rate until 24 hours of exposure to the etching composition. It can be confirmed that it has a life time

In addition, after preparing the etching compositions of Examples 3 to 14 and Comparative Preparation Example 2 as described in Table 4 below, the etching compositions were exposed at 70°C, and nitriding in 3 hour increments until 3 to 24 hours after exposure The substrates on which the laminate of the titanium film and the tungsten film were formed were respectively immersed in the etching composition to perform etching, and the etching rate, selectivity, and uniformity of the tungsten film were measured.

At this time, the etching method, the etching rate and the method of measuring the selectivity were performed in the same manner as above. However, the uniformity of the tungsten film was measured by measuring the thickness at an arbitrary location, and the resulting thickness deviation was evaluated according to the following criteria.

<Criteria for evaluating uniformity of tungsten film>

○: Thickness uniformity is good as the thickness deviation (etch rate) deviation is less than 0.05Å/min.

△: Thickness deviation (etching rate) deviation is 0.05Å/min to 1Å/min, and thickness uniformity is generally good

Ⅹ: Thickness uniformity is poor due to thickness deviation (etching speed) exceeding 1Å/min

The results are shown in Table 4 below.

Composition of etching composition (%) Etching speed (Å/min) Selection ratio
(TiN/W) Tungsten film uniformity Phosphoric acid nitric acid Ammonium additive water nitrification
Titanium film
(TiN) Tungsten film
(W) Kinds content Comparative Production Example 2 65 15 - - Balance 6.77 7.42 0.91 Ⅹ Preparation Example 3 ammonia 0.05 6.80 7.43 0.92 △ Preparation Example 4 0.1 6.74 7.40 0.91 ○ Preparation Example 5 One 6.81 7.51 0.91 ○ Preparation Example 6 AC 0.05 6.81 7.48 0.91 △ Preparation Example 7 0.1 6.82 7.52 0.91 ○ Preparation Example 8 One 6.77 7.45 0.91 ○ Preparation Example 9 AP 0.05 6.74 7.52 0.90 △ Preparation Example 10 0.1 6.82 7.41 0.92 ○ Preparation Example 11 One 6.75 7.45 0.91 ○ Preparation Example 12 AN 0.05 6.74 7.41 0.91 △ Preparation Example 13 0.1 6.80 7.46 0.91 ○ Preparation Example 14 One 6.82 7.50 0.91 ○

In Table 4, AC stands for ammonium chloride, AP stands for ammonium phosphate, and AN stands for ammonium nitrate.

As shown in Table 4, the etching compositions of Examples 3 to 14 using various ammonium compounds have the same level of etching rate and selectivity as compared to the etching composition of Comparative Preparation Example 2 that does not contain an ammonium compound. Although the results of were shown, the characteristics of the tungsten film were significantly improved in terms of uniformity. This result is due to the effect of improving the uniformity of the ammonium compound contained in the etching compositions of Preparation Examples 3 to 14.

In addition, after each of the etching compositions of Examples 15 and 16 were prepared as described in Table 5 below, the substrate on which the laminate of the titanium nitride layer and the tungsten layer was formed was exposed to the etching composition for 30 minutes and etched using the same. The speed, selectivity and uniformity of the tungsten film were measured.

At this time, the etching method, the etching rate and the method of measuring the selectivity were performed in the same manner as above. The results are shown in Table 5 below together with the results of Comparative Preparation Example 1.

Composition of etching composition (% by weight) evaluation Etching speed (Å/min) Selection ratio
(TiN/W) Phosphoric acid nitric acid Ammonium
compound Acetic acid Secondary oxidizing agent water nitrification
Titanium film
(TiN) Tungsten film
(W) Comparative Production Example 1 72 1.9 - 13.6 - Balance 6.58 6.47 1.02 Preparation Example 15 72 1.9 APS 0.1 - PTSA
13.6 Balance 7.90 7.46 1.05 Preparation Example 16 72 1.9 APS 0.1 - PIA
One Balance 6.93 8.26 0.84

In Table 5, PTSA (Para-toluene sulfonic acid), PIA (Periodic acid), and APS (Ammonium persulfate).

As shown in Table 5, Examples 15 and 16 exhibited an increased etching rate with an excellent selectivity compared to the etching composition of Comparative Preparation Example 1.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It belongs to the scope of rights of

Claims (5)

Lamination of a titanium nitride film and a tungsten film containing (a) 50 to 80% by weight of phosphoric acid, (b) 5 to 20% by weight of nitric acid, (c) 0.01 to 1% by weight of an ammonium compound, and (d) the remainder of the solvent Body etching composition. The method of claim 1,
The (c) ammonium compound is ammonium sulfate, ammonium persulfate, ammonium hydroxide, ammonium chloride, ammonium phosphate, ammonium nitrate And that is selected from the group consisting of a mixture thereof, the etching composition for a laminate of a titanium nitride film and a tungsten film. The method of claim 1,
The etching composition includes periodic acid, iodic acid, ortho periodic acid, hypoiodous acid, chloric acid, percholic acid, hypochlorous acid. Hypochlorous acid, chlorous acid, perbromic acid, bromic acid, bromous acid, methanesulfonic acid, para-toluenesulfonic acid ( Para-toluene sulfonic acid) Selected from the group consisting of ethanesulfonic acid, 1-Hexanesulfonic acid, 1-Octanesulfonic acid, Benzenesulfonic acid, and mixtures thereof The etching composition for a laminate of a titanium nitride film and a tungsten film further comprising a secondary oxidizing agent. (a) 50 to 80% by weight of phosphoric acid, (b) 5 to 20% by weight of nitric acid, (c) 0.01 to 1% by weight of an ammonium-based compound, and (d) a titanium nitride film using an etching composition containing a residual amount of a solvent And etching the stacked body of the tungsten film. A semiconductor device comprising a laminate of a titanium nitride layer and a tungsten layer etched by the etching method according to claim 4.

Images