JP2000282096A - Corrosion inhibitor for metal, cleaning liquid composition containing the same and cleaning using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a corrosion inhibitor for a metal without corrosiveness when cleaning a metal, especially copper or a copper alloy, a cleaning liquid composition capable of removing impurities without corroding a copper wiring by adding the corrosion inhibitor to a cleaning liquid for a semiconductor device having a metal wiring, especially the copper wiring and to provide a method for cleaning using the cleaning liquid composition. SOLUTION: This corrosion inhibitor for a metal comprises one or more kinds of compounds selected from imidazoles, thiazoles and triazoles having at least one amino group or at least one thiol group in the molecule. The cleaning liquid composition is obtained by adding the corrosion inhibitor to a cleaning liquid suitable for cleaning a metal to be cleaned. The method for cleaning uses the cleaning agent composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal corrosion inhibitor, a cleaning liquid composition and a cleaning method. More specifically, a cleaning liquid composition that is not corrosive to copper or a copper alloy, and thus is optimal for cleaning semiconductor devices having copper wiring, and copper wiring of semiconductor devices using the cleaning liquid composition. It relates to a cleaning method.

[0002]

2. Description of the Related Art In recent years, various materials have been developed for higher integration and higher performance of semiconductor devices. Above all, as a wiring material in a device, a wiring material having a lower resistance is required to improve a transmission speed of an electric signal in the wiring. Conventionally, aluminum or its alloy has been used because of its easy workability.However, it is considered that these materials are insufficient in view of the performance of devices required for future high performance, high speed processing, Copper wiring has attracted attention as a material with lower resistance.

Conventionally, wiring of a semiconductor device is formed by forming a metal to be a wiring on a silicon wafer, forming a wiring through a lithography process and a dry etching process, and filling an insulating film between the wirings. Was common. However, since copper wiring is difficult to process by a dry etching process, it has hardly been used until now. However, in recent years, a chemical mechanical polishing method (Chemical Mechanical Polishing, hereinafter abbreviated as CMP) using a special abrasive and a polishing pad has been developed.
Attention has been paid to a wiring forming method by a damascene method using P.

In this method, an insulating film is first formed, a wiring groove is formed by a lithography step and a dry etching step, and then copper is buried in the groove by forming copper, and then the groove is formed by CMP. The other copper film is removed by polishing. However, this CM
In the formation of copper wiring by P, a large amount of abrasive dust generated by polishing and polishing after polishing of copper, metal impurities contained in polishing agent and polishing pad, etc. adhere to the front and back surfaces of the wafer, It is necessary to clean the polished surface.

In general, in order to remove particles on the wafer surface, the wafer surface and the zeta potential of the particles must have the same sign to have an electric repulsion, and particles that have once separated from the surface must not be reattached. It is said to be important. In particular, when the atmosphere to be cleaned is alkaline, most of the materials show a negative zeta potential, and therefore, it is preferable to perform the cleaning with an alkaline solution. In order to remove metal impurities, it is desirable to use an acidic solution having strong metal dissolving power.

[0006] However, it is known that copper is easily corroded by an alkaline solution or an acidic solution, and when such a solution is used to clean a wafer surface on which copper wiring is exposed, the copper surface after the cleaning is usually used. Are eroded by corrosion, causing problems such as an increase in wiring resistance and disconnection.

On the other hand, relatively many substances are known as corrosion inhibitors for preventing corrosion of copper, but there are restrictions on their use for semiconductor devices. That is, since the wiring pattern of a semiconductor device is extremely fine, even if the total amount of corrosion is suppressed by a corrosion inhibitor, pitting occurs or the surface condition becomes rough, which adversely affects the performance of the device. It is necessary to select a corrosion inhibitor that does not occur.

[0008] Further, a cleaning agent usually used for a semiconductor device sometimes has extremely low alkali and acid concentrations, and in such a case, the addition of a corrosion inhibitor becomes extremely low. It is difficult to predict from such corrosion inhibitors.

[0009]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to provide a semiconductor device which is not corrosive when cleaning metals, especially copper or copper alloys, and thus has copper wiring. An object of the present invention is to provide a cleaning agent which is most suitable for cleaning, a cleaning liquid composition containing the same and a cleaning method.

[0010]

That is, a first aspect of the present invention is to provide at least one compound selected from imidazoles, thiazoles and triazoles containing at least one amino group or thiol group in the molecule. The present invention relates to a metal corrosion inhibitor comprising:

As a result of the research, the present inventors obtained the above compound as a substance having a high corrosion inhibiting effect by being added to a metal, especially copper or a copper alloy, and further to a cleaning solution usually used for copper wiring in a semiconductor device, The present invention has been completed.

The metal corrosion inhibitor according to the invention consists of the above-mentioned compounds which, although not elucidated in detail, are thought to act on metals, especially copper surfaces, whereby corrosion of the metal surfaces is reduced. Is prevented.

Particularly preferred imidazoles constituting the compound are 2-mercaptoimidazoline and 2
-Mercapto-1-methylimidazole, thiazoles such as 2-mercaptothiazoline and 2-aminothiazole, and triazoles such as 3
-Aminotriazole, 4-aminotriazole, 2,
5-Diaminotriazole, 3-mercaptotriazole and 3-amino-5-mercaptotriazole can be mentioned. These can be used alone or as a mixture thereof.

A second aspect of the present invention relates to a cleaning liquid composition containing the corrosion inhibitor.
In the present invention, a cleaning liquid containing no corrosion inhibitor is simply referred to as “cleaning liquid”, and a cleaning liquid containing a corrosion inhibitor is referred to as “cleaning liquid composition” to distinguish between them.

When the corrosion inhibitor is contained in a commonly used metal cleaning liquid, a cleaning liquid composition having no corrosiveness can be provided. In particular, the characteristics of the present invention can be sufficiently exerted by using the composition as a cleaning liquid composition for a semiconductor device having copper or a copper alloy, and further, copper wiring. As the cleaning solution, either an alkaline solution or an acidic solution can be used.

The concentration of the corrosion inhibitor in the cleaning liquid composition is preferably from 0.0001 to 10% by weight, more preferably from 0.001 to 1% by weight. If the concentration is too low, it may not be possible to obtain a sufficient corrosion-inhibiting effect, while if the concentration is too high, further improvement in the corrosion-inhibiting effect cannot be exhibited, but rather other adverse effects, such as cleaning of semiconductor devices. When used, the control of the semiconductor cleaning step becomes difficult, such as an increase in the amount of the corrosion inhibitor adsorbed on the semiconductor surface, and this is not preferable because a negative surface occurs. In order to obtain the cleaning liquid composition, the corrosion inhibitor of the present invention may be added to the cleaning liquid and stirred to dissolve the corrosion inhibitor.

The alkaline solution is not particularly limited as long as it is generally used as a washing solution. An aqueous solution of an inorganic compound such as sodium hydroxide, potassium hydroxide or ammonium hydroxide, or an organic compound such as tetramethylammonium hydroxide or choline is used. Can be used. Among them, for semiconductor devices, it is preferable to use an aqueous solution of a compound such as purified ammonium hydroxide, tetramethylammonium hydroxide, and choline to remove metal impurities and fine particles, and an aqueous ammonium hydroxide solution is particularly preferable. .

The acidic solution is not particularly limited as long as it is generally used for a washing solution, and hydrochloric acid, hydrofluoric acid, sulfuric acid,
Inorganic acidic solutions such as nitric acid, oxalic acid, citric acid,
Organic acidic solutions such as malonic acid, malic acid, fumaric acid, and maleic acid can be used. Among them, for semiconductor devices, to remove metal impurities and fine particles, purified hydrochloric acid, hydrofluoric acid, sulfuric acid, nitric acid, oxalic acid,
It is preferable to use an acidic aqueous solution such as citric acid.

The alkaline solution or acidic solution to which the corrosion inhibitor is added may be used as it is, or may be used by mixing with another agent which does not hinder the performance of the corrosion inhibitor. Above all, it may be used as a mixture with a hydrogen peroxide solution, ammonium fluoride or the like purified for use in semiconductor devices.

Further, a third aspect of the present invention relates to a method for cleaning a semiconductor device using the cleaning solution composition.

Since the corrosion inhibitor of the present invention does not limit the metal to be cleaned, it is generally used by adding it to a cleaning solution for metals. Particularly, the corrosion inhibitor has a remarkable effect when used for cleaning copper and copper alloys.

The corrosion inhibitor of the present invention is suitable for being added to a cleaning solution for cleaning a semiconductor device having metal wiring, particularly copper wiring. Since the wiring pattern on the wafer constituting the semiconductor device is extremely fine, it is required to suppress the amount of corrosion as a whole and not to cause pitting or roughen the surface state. When the wafer is cleaned with the cleaning liquid composition of the present invention, attached metal impurities and fine particles are removed, but pitting and surface roughness do not occur.

For cleaning a wafer with a cleaning liquid composition,
The immersion cleaning method by directly immersing the wafer in the cleaning liquid composition, the method using ultrasonic irradiation in combination with the immersion cleaning method, the brush cleaning method in which the cleaning liquid composition is washed with a brush while spraying the cleaning liquid composition on the wafer surface, and the brush cleaning and super cleaning A method in which sound wave irradiation is used in combination can be used. When washing, the cleaning liquid composition can be heated.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Examples 1 to 3 and Comparative Examples 1 to 30 1% by weight of aqueous ammonia was used as a cleaning liquid, and 0.01% (by weight) of the corrosion inhibitor of the present invention described in Table 1 was added to obtain a cleaning liquid composition of the present invention. As a comparative example, a cleaning solution to which the corrosion inhibitor of the present invention was not added (including a cleaning solution to which no corrosion inhibitor was added) was used. A silicon wafer having a Cu film formed thereon by sputtering was immersed in the cleaning liquid composition and the cleaning liquid for 30 minutes as a test piece, and the thickness of the Cu film before and after immersion was measured. It was calculated and the corrosion prevention effect was determined. The surface before and after the immersion was observed with an electron microscope, and the state of the Cu film surface was observed. The film thickness was measured using a sheet resistance measuring device manufactured by Napson Corporation, and a method of converting the film resistance from the sheet resistance value was used. Table 1 shows the results. Table 1 confirms that the corrosion inhibitor of the present invention is extremely effective in preventing copper corrosion by an alkaline solution.

[0026]

[Table 1]

Examples 4 to 5 and Comparative Examples 4 to 5 A 0.1% by weight aqueous solution of hydrofluoric acid or a 1% by weight aqueous solution of hydrochloric acid was used as a washing solution, and the corrosion inhibitor of the present invention shown in Table 2 was used in an amount of 0.01%. % By weight to obtain a cleaning liquid composition of the present invention. As a comparative example, a cleaning solution to which no corrosion inhibitor was added was prepared. A silicon wafer on which a Cu film 10000Å was formed by a sputtering method was immersed in the cleaning liquid composition and the cleaning liquid as a test piece for 30 minutes.
Measure the thickness of the film, calculate the dissolution rate from the change in film thickness,
The corrosion prevention effect was determined. The surface before and after the immersion was observed with an electron microscope, and the state of the Cu film surface was observed. The method of measuring the film thickness is the same as above. Table 2 shows the results. From Table 2, it is confirmed that the corrosion inhibitor of the present invention is extremely effective in preventing copper corrosion by an acidic solution.

[0028]

[Table 2]

In Tables 1 and 2, * 1 to * 7 and symbols are as follows. - corrosion inhibitor * 1: 2-mercapto thiazoline _{C 3 H 5 NS 2 * 2} : 3- aminotriazole _{C 2 H 4 N 4 * 3} : 2- main mercapto imidazoline _{C 3 H 6 N 2 S *} 4: Mechirupenchi NOL CH ₃ CH ₂ C
(CH ₃ ) (OH) CCH * 5: β, β′-thiodipropionic acid S (CH ₂ C
H ₂ COOH) ₂ · Cleaning solution * 6: 0.1% by weight hydrofluoric acid * 7: 1% by weight hydrochloric acid · Surface condition ○: No change ×: Rough surface The above embodiment describes the cleaning of copper wiring in a semiconductor device. However, similar results were obtained for copper and copper alloys. If a cleaning liquid is appropriately selected, an excellent anticorrosion effect can be exhibited also for cleaning metals other than copper.

[0030]

As described above, the metal corrosion inhibitor according to the first aspect of the present invention comprises at least one selected from imidazoles, thiazoles and triazoles containing at least one amino group or thiol group in the molecule. And prevents corrosion of metals, especially copper or copper alloys.

According to a second aspect of the present invention, the metal corrosion inhibitor is added to a cleaning liquid suitable for the metal to be cleaned.
As the metal is cleaned, it removes impurities and prevents corrosion of the underlying metal.

Further, according to the third aspect of the present invention, the cleaning liquid composition cleans a metal, particularly a copper wiring in a semiconductor device, so that impurities are removed and the surface of the copper wiring is roughened or pitched. do not do.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Takashima 2-1 Kita-sode, Sodegaura-shi, Chiba F-term (reference) 4H003 BA12 DA09 DA15 EA03 EA05 EA23 EB20 EB21 ED02 FA15 FA28 4K053 PA06 PA14 RA15 RA16 RA17 RA19 RA21 RA22 RA23 RA45 RA46 RA47 RA52 RA59 RA63 4K062 AA03 BA08 BA11 BB12 BB18 BB22 EA02 EA09 FA09 FA13

Claims (16)

[Claims] 1. A metal corrosion inhibitor comprising at least one compound selected from imidazoles, thiazoles and triazoles containing at least one amino group or thiol group in the molecule. 2. The metal corrosion inhibitor according to claim 1, wherein the imidazoles are 2-mercaptoimidazoline and 2-mercapto-1-methylimidazole. 3. The metal corrosion inhibitor according to claim 1, wherein the thiazoles are 2-mercaptothiazoline and 2-aminothiazole. 4. The method according to claim 1, wherein the triazoles are 3-aminotriazole, 4-aminotriazole, 2,5-diaminotriazole, 3-mercaptotriazole and 3-amino-5-mercaptotriazole. Metal corrosion inhibitor. 5. A copper or copper alloy corrosion inhibitor comprising at least one compound selected from imidazoles, thiazoles and triazoles containing at least one amino group or thiol group in the molecule. 6. A method for preventing corrosion of metal wiring in a semiconductor device, comprising at least one compound selected from imidazoles, thiazoles and triazoles containing at least one amino group or thiol group in the molecule. Agent. 7. A cleaning liquid composition comprising the metal corrosion inhibitor according to claim 1 added to the cleaning liquid. 8. A cleaning solution composition for a semiconductor device having metal wiring, wherein the metal corrosion inhibitor according to claim 1 is added to the cleaning solution. 9. A cleaning liquid composition for a semiconductor device having copper wiring, wherein the metal corrosion inhibitor according to claim 1 is added to the cleaning liquid. 10. The cleaning liquid composition according to claim 7, wherein the cleaning liquid is an alkaline solution. 11. The cleaning liquid composition according to claim 10, wherein the alkaline solution is an aqueous ammonia solution. 12. The cleaning liquid composition according to claim 7, wherein the cleaning liquid is an acidic solution. 13. A cleaning method, comprising cleaning a metal with the cleaning liquid composition according to claim 7. Description: 14. A cleaning method, comprising cleaning a semiconductor device having a metal wiring with the cleaning liquid composition according to claim 7. 15. The cleaning method according to claim 14, wherein the metal wiring is a copper wiring. 16. A semiconductor device having copper wiring,
The metal corrosion inhibitor according to any one of claims 1 to 4, which is contained in an aqueous solution containing 0.001 to 10% by weight of ammonia.
A cleaning method characterized by cleaning with a cleaning liquid composition added with 0001 to 10% by weight.