KR101790494B1 - Solution for etching silicon oxide layer - Google Patents

Abstract

The silicon oxide film etching solution of the present invention includes a metal film corrosion inhibitor having at least one nitrogen-containing heterocyclic compound, so that the silicon oxide film containing at least one metal film can be selectively etched without the loss of the metal film when the silicon oxide film is etched . Therefore, it can be usefully used for manufacturing various semiconductor devices.

Description

[Solution for etching silicon oxide layer]

The present invention relates to a silicon oxide film etching solution, and more particularly, to a silicon oxide film etching solution capable of selectively etching a silicon oxide film without affecting a metal film.

In a manufacturing process of a thin film display device such as a TFT-LCD, a silicon oxide film or a nitride film is used for electrical isolation between metal wires in an electric circuit design. The silicon oxide film or the nitride film is etched in a predetermined form if necessary, wherein a buffered oxide etchant containing HF and NH ₄ F is used.

Gate and Source / Drain When forming a circuit board in a semiconductor or thin film display manufacturing process, a contact hole (contact) necessary for forming a contact metal in a silicon oxide film formed for the purpose of electrical isolation of a metal device the etchant may be used for etching a part of the silicon oxide film so that a hole can be formed.

In the conventional silicon oxide film etching, the metal layer is not directly exposed, or the metal layer is used in a state where there is a barrier film between the oxide layer and the metal layer, so that the metal layer is not directly affected. However, in general, there arises a problem of affecting the inner metal film due to a pin hole or direct damage of some barrier film using a silicon nitride film.

Some of the additives are applied to improve the problem, but the effect is not enough. In particular, when there is a metal film laminate structure or another metal adjacent to the metal film, galvanic corrosion occurs rapidly upon contact with the etching solution. This is a problem caused by the electrical characteristics between the metal films, so that it is difficult to solve the problem with the etchant alone, and yet there is no fundamental solution to the galvanic corrosion of the etchant.

There is a method of reducing the contact time of the etchant by controlling the process conditions other than the above-mentioned etching solution, but the problem of unetch failure of the silicon oxide film is reversed, so that it affects the post-process and is not a fundamental solution .

With the technology related to the silicon oxide film etching solution, Korean Patent Laid-Open Publication No. 2008-0082739, Patent Registration No. 10-1316054, Patent Registration No. 10-1094663, and Patent Application Publication No. 2010-0053175, etc., Lt; / RTI > However, these etchants do not solve the above problems.

Therefore, there is a need for an etching solution capable of controlling galvanic corrosion caused by integrated corrosion and potential difference between metals as well as surface protection of a metal film during silicon oxide film etching.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide an etching solution capable of selectively etching only a silicon oxide film without affecting a metal film, thereby protecting a surface of a metal film, and more effectively controlling corrosion and galvanic corrosion will be.

According to an aspect of the present invention,

0.1 to 50% by weight of an inorganic acid, an organic acid or a mixture thereof;

0.1 to 40% by weight of ammonium fluoride;

0.01 to 10% by weight of a metal film corrosion inhibitor comprising a nitrogen-containing heterocyclic compound; And

And a remaining amount of water.

The silicon oxide film etchant of the present invention can selectively etch the silicon oxide film without loss of the metal film when the silicon oxide film containing the metal film is etched by using the nitrogen-containing heterocyclic compound as a metal film corrosion inhibitor. Therefore, the silicon oxide film etchant can be usefully used in various semiconductor devices.

1 is an SEM image of a cross-section of a specimen etched using an etching solution according to Example 2 and Comparative Example 2. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It should be understood, however, that the present invention is not intended to be limited to any particular embodiment, but is to be understood as all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, the silicon oxide film etching solution of the present invention containing a nitrogen-containing heterocyclic compound-containing metal film corrosion inhibitor will be described in more detail.

According to one embodiment, 0.1 to 50% by weight of an inorganic acid, an organic acid or a mixture thereof; 0.1 to 40% by weight of ammonium fluoride; 0.01 to 10% by weight of a metal film corrosion inhibitor comprising a nitrogen-containing heterocyclic compound; And a remaining amount of water.

The metal film corrosion inhibitor containing a nitrogen-containing heterocyclic compound contained in the etchant can protect the surface of the metal film by etching the metal film-containing silicon oxide film to more effectively control the direct corrosion of the metal film and the galvanic corrosion, So that etching processing can be selectively performed. Namely, the nitrogen-containing heterocyclic compound used as a corrosion inhibitor is a form containing a nitrogen atom in the ring and is easy to move to the metal surface and easily forms a protective film on the metal surface, thereby preventing the metal surface from contacting the etchant Thereby protecting the metal film from corrosion.

The nitrogen-containing heterocyclic compound may be a nitrogen-containing heterocyclic compound containing 1 to 3 nitrogen atoms in the ring, and examples thereof include a pyrazole compound, an imidazole compound, a pyridine compound, a quinoline compound, Based compounds, triazine-based compounds, piperazine-based compounds, triazine-based compounds, and triazole compounds.

The pyrazole compound, which is an example of the nitrogen-containing heterocyclic compound, may include at least one of pyrazole, tartrazine, phenylbutazone, and the like.

The imidazole compound, which is an example of the nitrogen-containing heterocyclic compound, may include at least one imidazole, methylimidazole, aminopropyl imidazole, benzimidazole, imidazoline, and the like.

The pyridine compound as an example of the nitrogen-containing heterocyclic compound may include at least one of pyridine, methylpyridine, dimethylpyridine, trimethylpyridine, methylethylpyridine, aminopyridine, benzopyridine, and the like.

The quinoline-based compound, which is an example of the nitrogen-containing heterocyclic compound, may include at least one of quinoline, isoquinoline, and the like.

The pyrimidine compound, which is an example of the nitrogen-containing heterocyclic compound, may include at least one of pyrimidine, purine, and the like.

The piperazine compound, which is an example of the nitrogen-containing heterocyclic compound, may include at least one of piperazine, methylpiperazine, hydroxyethylpiperazine, benzylpiperazine, and the like.

The triazine-based compound, which is an example of the nitrogen-containing heterocyclic compound, may include triazine and the like.

The triazole type compound, which is an example of the nitrogen-containing heterocyclic compound, may include one or more of triazole, benzotriazole, methylbenzotriazole, tolurriazole, and the like.

The piperidine-based compound, which is an example of the nitrogen-containing heterocyclic compound, may include piperidine and the like.

These various nitrogen-containing heterocyclic compounds may have the form of a 4-membered to 6-membered ring, or a fused ring, in which at least one of the carbon atoms constituting the ring is substituted with a nitrogen atom, , Or a form that is further substituted by a sulfur atom.

According to the studies of the present inventors, it has been found that it is particularly preferable that one to three or less carbon atoms constituting the ring are substituted with a nitrogen atom.

 At least one of the hydrogen atoms present in the nitrogen-containing heterocyclic compound may be substituted with at least one of a halogen atom, a carboxyl group, a thiol group, a hydroxyl group, an amino group, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, a heteroalkyl group having 1 to 20 carbon atoms, An alkenyl group having 2 to 20 carbon atoms, an alkenylcarbonyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a heteroalkenyl group having 2 to 20 carbon atoms, a heteroalkynyl group having 2 to 20 carbon atoms, An aryl group having 6 to 30 carbon atoms, a heteroaryl group having 4 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, and the like.

According to one embodiment, the nitrogen-containing heterocyclic compound includes at least one of 3-methylpyridine and 2-methylpiperazine.

The nitrogen-containing heterocyclic compound may be used in an amount of about 0.01 to about 10% by weight, preferably about 0.01 to about 5% by weight, in the etchant. In this range, sufficient complexing ability .

According to one embodiment, the silicon oxide film etchant may use an inorganic acid and / or an organic acid as an acid component. As the inorganic acid, one or more of hydrofluoric acid, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, Is more preferable in terms of etching efficiency. As the organic acid, at least one of formic acid, acetic acid, and methanesulfonic acid may be used, and any organic acid known in the art may be used without limitation. The inorganic acid and the organic acid may be used singly or in combination. In this case, the inorganic acid and the organic acid may be mixed in a weight ratio of 1: 9 to 9: 1, respectively.

The inorganic acid and / or organic acid may be used in an amount of about 0.1 to about 50 wt.%, Preferably about 0.1 to about 30 wt.% In the silicon oxide film etchant. In this range, .

According to one embodiment, the silicon oxide film etchant includes ammonium fluoride, which acts as an etching aid, and is used in the etchant in an amount of about 0.1 to about 40 wt%, preferably about 5 to about 30 wt% As a result, it becomes possible to sufficiently perform the role of the etching aid in such a range.

According to one embodiment, the etching rate of the silicon oxide film can be controlled by adjusting the concentrations of the inorganic acid and / or organic acid and ammonium fluoride. In this case, the inorganic acid and / or organic acid may be 100 parts by weight or less based on 100 parts by weight of ammonium fluoride, and the concentration of ammonium fluoride is preferably 35% or less.

According to one embodiment, the silicon oxide film etchant may include water as a solvent, and the content thereof may be used in an amount such that the total etchant content is 100 wt%.

According to one embodiment, the silicon oxide etchant may further contain 0.01 to 10% by weight of a reducing agent based on the total weight. Examples of the reducing agent include cysteine, thioglycolic acid, cysteamine, glutathione and ascorbic acid, Or more.

According to one embodiment, the silicon oxide film etchant may further include a surfactant. The silicon oxide etchant may be further added for the purpose of improving the wettability of the silicon oxide etchant, improving the foam characteristics of the additive, and improving solubility in other organic additives. have. It may be added in an amount of 0.0005 to 5% by weight based on the total weight of one or more selected from a nonionic surfactant, an anionic surfactant, a cationic surfactant and an amphoteric surfactant, 0.001 to 2% by weight of a nonionic surfactant and / or an amphoteric surfactant may be added. When the content of the surfactant is 0.0005 wt% or less, no effect can be expected. When the surfactant is added in an amount of 5 wt% or more, problems of precipitation of the surfactant may occur due to the solubility problem. As such a surfactant, for example, acetylene diol, alkylamine, alkylcarboxylic acid, pluronic polymer (block copolymer of ethylene oxide and propylene oxide) and the like may be used.

Further, an organic solvent may be further added to the silicon oxide film etching solution according to one embodiment. It is possible to improve the wettability and solubility of the organic additive in the same manner as the above-described surfactants, and in some cases, to improve the storage stability of the product at low temperatures. Specifically, as the organic solvent, at least one kind selected from the group consisting of methanol, ethanol, propanol, ethyleneglycol, ethyltriglycol, butyldiglycol, polyethylene glycol, polypropylene glycol, 0.1 to 10% by weight based on the total weight of the oxide film etching solution. Preferably 0.2 to 5% by weight, and when the organic solvent is added in an amount of 10% by weight or more, erosion of the organic layer (photoresist pattern) patterning the silicon oxide film may occur.

According to one embodiment, the metal forming the complex with the nitrogen-containing heterocyclic compound as the corrosion inhibitor is at least one selected from the group consisting of tungsten (W), titanium (Ti), molybdenum (Mo), nickel (Ni) Aluminum, Ag (gold), Co (cobalt), and the like. However, the present invention is not limited thereto. In the case of the mixed metal, a mixed metal including two or more metals, an alloy, and a metal compound in the form of a metal silicide (Metal-Si _x ) may be included.

The nitrogen-containing heterocyclic compound-containing metal film corrosion inhibitor may be used in an amount of about 0.01 to about 10 wt% based on the total weight of the silicon oxide film etchant. .

The silicon oxide film etching solution according to one embodiment as described above can be manufactured by the following method.

A method of manufacturing a silicon oxide film etchant according to an embodiment of the present invention includes a step of dissolving an inorganic acid and / or an organic acid; And ammonium fluoride to prepare an aqueous solution; And adding a nitrogen-containing heterocyclic compound-containing metal film corrosion inhibitor to the aqueous solution.

Further, the pre-stage of the step of adding the metal film corrosion inhibitor; Post step; Or may include a degassing step in both the pre-stage and the post-stage. In the case where the degassing process is performed in both the previous stage and the latter stage, the first degassing and the second degassing can be distinguished.

In the preparation method, the water, inorganic acid and / or organic acid; A metal film corrosion inhibitor containing a nitrogen-containing heterocyclic compound; And ammonium fluoride are as described above, and examples thereof are also as described above.

The temperature and pressure at which the etchant can be produced are not particularly limited. However, the temperature and pressure at which the etchant can be produced are not particularly limited, A condition of 1 atm may be used.

The order of introduction of the raw materials in the preparation of the aqueous solution is not particularly limited, but inorganic acids and / or organic acids and ammonium fluoride, ammonium fluoride and inorganic acids and / or organic acids may be added to the water sequentially. As a mixing method, a mixing method known in the art may be used without limitation. For example, a line mixer or a stirrer may be used. In such a mixing process, the order of introduction of the raw materials or the mixing method may be changed.

The degassing process, for example, the first degassing process and the second degassing process may be the same or different, and the degassing process removes oxygen to prevent the raw materials from being oxidized.

Such a degassing step may include, for example, a step of purging the aqueous solution while bubbling it with an inert gas. The primary and secondary degassing processes may be performed independently for 0.1 to 10 hours, or for 0.5 to 5 hours.

Examples of the inert gas used in the deaeration process include nitrogen, helium, neon, and argon, and the gas is bubbled into the aqueous solution. The flow rate of the inert gas used for such bubbling is not limited and can be used to such an extent that sufficient bubbling can be obtained.

In the degassing process, purging is performed together with the bubbling, which means blowing the upper portion of the container containing the aqueous solution to the inert gas. At this time, the flow rate of the inert gas is not limited, and it can be used to such an extent that sufficient purging can be obtained. For example, it can be used at a flow rate of about 1 to 10 liters / minute, or about 3 to 5 liters / minute, for purifying an aqueous solution of 1,000 kg.

The above-described silicon oxide film etching solution according to the present invention can be usefully used for manufacturing a device having a semiconductor structure, for example, etching a silicon oxide film containing a metal film in a gate electrode forming process in a semiconductor film having a high degree of integration.

That is, in the step of fabricating the semiconductor structure element using the silicon oxide film etching solution according to the present invention, the step of selectively etching the silicon oxide film among the silicon oxide film including the metal film can be performed to manufacture the semiconductor device.

Hereinafter, embodiments of the present invention will be described in more detail so that those skilled in the art can readily implement the present invention. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Examples 2 to 6 and Comparative Examples 1 to 4

Preparation of silicon oxide film etching solution

The respective components were mixed with the component contents shown in Table 1 below to prepare the etching solutions of Examples 2 to 6 and the etching solutions of Comparative Examples 1 to 4. The water content was such that the total weight of the composition was 100 wt%.

division HF / NH ₄ F composition
(weight %) Corrosion inhibitor
(weight %) reducing agent
(weight %) Surfactants
(weight %) HF NH ₄ F Kinds content Kinds content Kinds content Comparative Example 4 0.1 17 Pico 1.0 x - x - Example 2 2.5 17 Pico 0.01 x - x - Example 3 2.5 17 Pico 1.0 x - x - Example 4 2.5 17 Pico 0.5 Cysteine 0.1 AD 0.01 Example 5 2.5 17 MP 1.0 x - x - Example 6 2.5 17 Pico 0.5 x - x - DMI 0.5 Comparative Example 1 2.5 17 x x - x - Comparative Example 2 2.5 17 x TGA 0.1 AD 0.01 Comparative Example 3 2.5 17 IDA 1.0 x - X -

- Abbreviation explanation

PICO: 3-methylpyridine,

MP: 2-methylpiperazine,
DMI: 1,2-dimethylimidazole

delete

delete

IDA: Iminodiacetic acid,

TGA: Thioglycolic acid,

AD: nonionic surfactant (acetylene diol)

Experimental Example 1: Evaluation of corrosion characteristics

In order to evaluate the corrosion characteristics of the etchant prepared in Examples 2 to 6 and Comparative Examples 1 to 4, the etch rate of the silicon oxide film, the corrosion resistance of the metal single film and the laminate film were compared as follows.

a) Evaluation of etch rate of silicon oxide film

The specimens used in the evaluation were formed into a single layer of silicon oxide on a silicon wafer and cut into a size of 20 mm x 30 mm.

In the evaluation method, 100 g of the evaluation chemical solution was filled in a transparent plastic container, and the test specimens prepared in advance in accordance with the etching rate were etched at a temperature of 25 캜 by using a constant temperature water bath.

The film thickness was measured using a non-contact type thin film thickness measuring apparatus (ST-2000DLXn, K-MAC).

b) Metal film corrosion evaluation

The specimens used for corrosion evaluation were prepared as a single membrane and a laminated membrane. The single film formed a single film of cobalt silicide (CoSi _x ) on a silicon wafer, and the laminate film was formed of a tungsten (W) / titanium nitride (TiNx) / cobalt silicide (CoSi _x ) / polysilicon ) Were sequentially laminated and cut into a size of 20 mm x 30 mm.

The evaluation method was the same as that for the silicon oxide film etching rate evaluation.

The corrosion characteristics of the specimens were observed using a scanning electron microscope (S-4800, Hitachi) and converted in units of Å / min based on the treatment time.

The etching rates and evaluation results for Examples 2 to 6 and Comparative Examples 1 to 4 are shown in Table 2 below.

division Silicon oxide film etching rate (Å / min) Single membrane surface state
(Surface SEM) Lamination Membrane Corrosion Rate
(Å / min) Comparative Example 4 30 ◎ below 10 Example 2 500 ◎ 0 Example 3 500 ◎ 0 Example 4 500 ◎ 0 Example 5 500 ◎ 0 Example 6 500 ◎ 0 Comparative Example 1 500 △ 2242 Comparative Example 2 500 X 3651 Comparative Example 3 500 ○ 723

- Evaluation criteria for single membrane surface condition

X: very bad

?: Poor

○: Good

◎: Very good

As shown in Table 2, in Examples 2 to 6 including the metal film corrosion inhibitor according to the present invention, corrosion to the laminated film hardly occurred while maintaining the etching rate for the silicon oxide film. Thus, it can be seen that the surface state of the single film is very good. 1 is a cross-sectional SEM image of a specimen etched using an etchant according to Example 2 and Comparative Example 2. Fig. In the case of Comparative Example 2, it can be confirmed that corrosion to the laminated film is severe.

Therefore, it can be seen that the silicon oxide film etching solution according to the present invention shows excellent etching ability selectively for the silicon oxide film while protecting the metal film.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (12)

0.1 to 50% by weight of hydrofluoric acid;
0.1 to 40% by weight of ammonium fluoride;
0.01 to 10% by weight of a metal film corrosion inhibitor comprising a nitrogen-containing heterocyclic ring compound; And
Water,
Wherein the nitrogen-containing heterocyclic ring compound contains at least 6.5 moles of hydrofluoric acid per 1 mole of nitrogen atoms of the nitrogen-containing heterocyclic ring compound. The method according to claim 1,
Wherein the nitrogen-containing heterocyclic compound-containing metal film corrosion inhibitor is a nitrogen-containing heterocyclic compound containing 1 to 3 nitrogen atoms in the ring. The method according to claim 1,
Wherein the nitrogen-containing heterocyclic ring compound is a pyridine-based compound, a pyrimidine-based compound, a piperazine-based compound, a triazine-based compound, or a mixture of two or more thereof. The method according to claim 1,
Wherein the nitrogen-containing heterocyclic ring compound is at least one selected from the group consisting of pyridine, methylpyridine, dimethylpyridine, trimethylpyridine, methylethylpyridine, aminopyridine, piperidine, benzopyridine, pyrimidine, piperazine, methylpiperazine, hydroxyethylpiperazine, Benzylpiperazine, triazine, or a derivative thereof, or a mixture of two or more thereof. The method according to claim 1,
Wherein the nitrogen-containing heterocyclic ring compound comprises at least one of 3-methylpyridine and 2-methylpiperazine. delete delete The method according to claim 1,
Wherein the hydrofluoric acid is 100 parts by weight or less based on 100 parts by weight of ammonium fluoride. The method according to claim 1,
Wherein the etchant further comprises a surfactant,
Wherein the surfactant is an acetylenic diol. The method according to claim 1,
Wherein the etching solution further comprises an organic solvent,
Wherein the organic solvent is methanol, ethanol, propanol, ethylene glycol, ethyl diglycol, ethyltriglycol, butyldiglycol, polyethylene glycol, polypropylene glycol. Hydrofluoric acid and ammonium fluoride to prepare an aqueous solution; And
Adding a nitrogen-containing heterocyclic ring compound-containing metal film corrosion inhibitor to the aqueous solution so that the amount of hydrofluoric acid per mol of the nitrogen atom of the nitrogen-containing hetero-six-membered ring compound is 6.5 mol or more;
The method of manufacturing a silicon oxide film according to claim 1, A method of manufacturing a semiconductor device having a semiconductor structure using the silicon oxide film etching solution according to any one of claims 1 to 5 and 8 to 10, comprising the steps of: selectively etching a silicon oxide film in a silicon oxide film including a metal film ≪ / RTI >

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