KR100856543B1 - Oxidation and diffusion barrier film formation method of copper wiring for semiconductor device - Google Patents

Abstract

A method of forming an oxidation and diffusion barrier film of a copper wiring for a semiconductor device is disclosed. The method of the present invention comprises the steps of: substituting silver for the surface of a copper wiring for a semiconductor device by a chemical mechanical polishing process using a slurry for chemical mechanical polishing processes containing a silver compound; And forming an oxidation and diffusion barrier layer on the surface substituted with silver by a chemical mechanical polishing process using a slurry for chemical mechanical polishing process for forming CoWP. According to the present invention, the oxidation and diffusion prevention film is formed on the copper wirings only by a continuous CMP process without activation of a separate additional process, ie, copper wirings using palladium, thereby improving productivity and process efficiency.

Description

Method for forming oxidation barrier or diffusion barrier of metal line of semiconductor device

1A to 1E are schematic views for explaining a method of forming an oxidation and diffusion barrier film of a copper wiring for a semiconductor device according to an embodiment of the present invention; And

FIG. 2 is an X-ray diffraction analysis graph of a substrate surface for each step of a method of forming an oxidation and diffusion barrier layer of a copper wiring for a semiconductor device according to an exemplary embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an oxidation and diffusion barrier film of copper wiring for semiconductor devices, and more particularly, to a method of forming an oxidation and diffusion barrier film for copper wiring for semiconductor devices using a chemical mechanical polishing method.

In the current semiconductor process, as the line width of the wire gradually decreases, the cross-sectional area of the wire decreases, resulting in an increase in resistance and a gap between the wires, resulting in signal delay. In order to reduce the signal delay, the wiring material is copper having low resistivity, and the insulating layer is replaced with a material having a lower dielectric constant.

The copper wiring is formed through a damascene process using chemical mechanical polishing (hereinafter referred to as CMP). The process of forming copper interconnects using CMP is a two-step process due to oxide subsidence and copper subsidence due to removal selectivity between materials. The first CMP process removes excess deposited copper and stops the diffusion barrier at the top of the trench by the removal selectivity. A second CMP process is performed to completely remove the copper and the diffusion barrier remaining on the diffusion barrier.

In a basic damascene structure, the device is destroyed by the fast diffusion of copper in silicon, so copper must be surrounded by a diffusion barrier on all sides to prevent this. However, as the primary and secondary CMP processes proceed after the copper forms electroplating, the upper portion of the copper wiring is exposed to the atmosphere without a diffusion barrier. The exposed copper wiring tends to be easily oxidized compared to tungsten and aluminum, so that the sheet resistance increases due to the generation of oxides as the time to stand in air or water becomes longer. In addition, due to the diffusion of copper, there is a problem that the insulating layer cannot be formed immediately after the copper wiring is formed. Therefore, SiCN or SiN is deposited on the copper wiring surface formed of CMP to prevent oxidation and diffusion of copper. SiCN or SiN has a much higher dielectric constant than the surrounding low dielectric materials, resulting in an increase in the capacitance of the overall interconnect structure.

Recently, research on the formation of a capping layer capable of simultaneously acting as an anti-oxidation film and an anti-diffusion film on the copper wiring by selective deposition through electroless plating has been actively conducted. CoWP is a Co series. In addition to the original expected effect by forming the capping layer on the copper wiring, there is an effect of greatly improving the electromigration characteristics, which greatly influences the life of the copper wiring, and as the line width of the wiring is reduced, the necessity is further increased.

Electroless plating allows CoWP to be selectively formed over copper wiring, which requires a new subsequent process after the CMP process to form the capping layer. In addition, in the case of CoWP, hypophosphite, a reducing agent, does not have activity on copper, and thus surface activation process using palladium (Pd) is required.

Accordingly, the present invention has been made in an effort to provide a method for forming an oxidation and diffusion barrier layer of a copper wiring for a semiconductor device capable of forming an oxidation and diffusion barrier layer in a continuous chemical mechanical polishing process instead of a new subsequent process.

According to an aspect of the present invention, there is provided a method for forming an oxidation and diffusion barrier of a copper wiring for a semiconductor device according to the present invention: a surface of a copper wiring for a semiconductor device by a chemical mechanical polishing process using a slurry for chemical mechanical polishing processes containing a silver compound. Replacing with silver; A chemical mechanical polishing process using a slurry for chemical mechanical polishing processes including a cobalt compound, a tungsten compound, and a phosphorus-containing reducing agent includes forming an oxidation and diffusion barrier layer on the surface substituted with silver. .

At this time, the slurry for chemical mechanical polishing process containing the silver-based compound is characterized in that the silver-based compound comprises an oxidizing agent, an abrasive, a corrosion inhibitor, a complex forming agent and a pH adjusting agent.

In addition, the slurry for the chemical mechanical polishing process for forming the oxidation and diffusion barrier layer is characterized in that the complexing agent, slurry stabilizer and pH adjuster is included in the reducing agent containing the cobalt compound, tungsten compound and phosphorus.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

The method for forming an oxidation and diffusion barrier layer of a copper wiring for a semiconductor device according to the present invention is a method of forming an oxidation and diffusion barrier, ie, a capping layer, on a copper wiring for a semiconductor device. The CMP process forms an oxidation and diffusion barrier on the copper wiring. Here, the continuous CMP process means that the continuation means that only the CMP process is performed without inserting another process other than temporal continuity.

Referring to FIG. 1, first, a surface of a copper wiring for a semiconductor device is replaced with silver by a CMP process using a CMP process slurry containing a silver compound (hereinafter, referred to as a CMP slurry for copper surface substitution). That is, in order to form CoWP without activation using palladium or the like on the copper wiring, the surface of the copper wiring is replaced with silver by a second CMP process. Subsequently, silver is substituted by CMP process using a CMP process slurry (hereinafter referred to as CMP slurry for CoWP formation) containing a cobalt (Co) compound, a tungsten (W) compound, and a reducing agent containing phosphorus (P). An oxidation and diffusion barrier film made of CoWP is formed on the surface.

As described above, the present invention is characterized in that the oxidation and diffusion prevention film, that is, the capping layer, is formed on the copper wiring for the semiconductor device by replacing only the slurry by the continuous CMP process, but the composition of the slurry is as follows. Same as

First, the CMP slurry for copper surface substitution is demonstrated.

The CMP slurry for copper surface substitution includes an oxidizing agent, an abrasive, a corrosion inhibitor, a complex forming agent, and a pH adjusting agent in a silver compound.

The oxidizing agent is characterized in that the peroxide-based oxidizing agent, in particular, hydrogen peroxide (hydrogen peroxide) is most preferred for the stability of the slurry. At this time, the hydrogen peroxide (hydrogen peroxide) is included in the range of 0.001 wt% to 30 wt%, especially for better results, the hydrogen peroxide (hydrogen peroxide) is preferably included in the range of 0.001 wt% to 10 wt%.

The abrasive may be at least one selected from the group consisting of metal oxides such as alumina, silica, zirconia, ceria, titania, and germania. Used. At this time, the abrasive is characterized in that the size is 5nm ~ 1000nm, it is preferable that the size is 10nm ~ 500nm for particularly effective results. On the other hand, when silica abrasive is used, it is characterized in that it is included in the range of 0.01 wt% ~ 15 wt%.

Corrosion inhibitors, characterized in that at least any one selected from among tetrazole (tetrazole) compound, derivatives substituted with an amine series and derivatives substituted with an alkyl (alkyl) series. At this time, the corrosion inhibitor is characterized in that it comprises 5-aminotetrazole (5-aminotetrazole) of 0.005M ~ 0.5M.

The complex forming agent may be used by mixing at least one selected from carboxylic acid compounds and at least one selected from amino acid compounds. Carboxylic acid compounds include acetic acid, formic acid, maleic acid, maleic acid, malic acid, tartaric acid, glutaric acid, citric acid and At least one selected from the group consisting of oxalic acid, the amino acid compound is arginine (arginine), phenylalanine (phenyl alanine), glutamine (glutamine), glycine (glycine), glutamic acid (glutamic acid) and serine (serine) At least one selected from the group consisting of. At this time, the complexing agent is characterized in that it is included in the range of 0.001M ~ 1M, it is preferable to include in the range of 0.005M ~ 0.5M in order to obtain particularly effective results.

As the pH adjusting agent, any one selected from the group consisting of sulfuric acid, potassium hydroxide and ammonia water is used.

Silver compounds include silver nitrate, silver (I) permanganate, silver chloride, silver iodide, silver phosphate, silver sulfate, silver carbonate, silver acetate, silver perchlorate, silver lactate, silver cyanide, silver (I) selenide, silver (I) telluride , silver benzoate, silver thiocyanate and potassium silver (I) is characterized in that at least one selected from the group consisting of cyanide. At this time, the silver compound is characterized in that it is included in the range of 0.001 wt% to 20 wt%, in particular, in order to effectively inhibit the oxidation of the exposed copper, the silver compound is included in the range of 0.005 wt% to 10 wt%. Preferably, in order to improve the oxidation resistance of copper, it is preferable to mix and use 2 or more types of silver type compounds.

On the other hand, the pH of the CMP slurry for copper surface substitution is characterized in that 7 to 14, particularly preferably 9 to 13.

Next, the CMP slurry for CoWP formation is demonstrated.

The CMP slurry for forming CoWP comprises a cobalt compound, a tungsten compound and a phosphorus containing reducing agent, a complex forming agent, a slurry stabilizer, and a pH adjusting agent.

The cobalt compound is characterized in that CoSO ₄ . At this time, CoSO ₄ is characterized in that it is included in the range of 0.05 wt% ~ 20 wt%, in particular CoSO ₄ is preferably included in the range of 0.1 wt% ~ 15 wt%.

The tungsten compound is characterized in that the sodium tungstate (sodium tungstate). At this time, sodium tungstate is characterized in that it is included in the range of 0.01 wt% to 20 wt%, in particular sodium tungstate is preferably included in the range of 0.1 wt% to 15 wt%.

The complex former is characterized in that the citrate (cirate) series, in particular sodium citrate (sodium citrate) is preferred. At this time, sodium citrate is characterized in that it is included in the range of 0.5 wt% to 50 wt%, in particular sodium citrate is preferably included in the range of 1 wt% to 30 wt%.

The slurry stabilizer may be a derivative of a tetrazole compound substituted with an amine or a derivative of a tetrazole compound substituted with an alkyl series. It is preferred to include 5-aminotetrazole. At this time, 5-aminotetrazole (5-aminotetrazole) is characterized in that it is included in the range of 0.001 wt% ~ 5 wt%, in particular 5-aminotetrazole (0.005-wt% ~ 3 wt%) It is preferable to be included in the range of.

Phosphorus-containing reducing agent is characterized in that the hypophosphite-based, in particular phosphorus-containing reducing agent is characterized in that sodium hypophosphite (sodium hypophosphite). At this time, sodium hypophosphite is characterized in that it is included in the range of 0.1 wt% ~ 30 wt%, sodium hypophosphite is preferably included in the range of 0.5wt% ~ 20 wt%.

pH adjuster is characterized in that the mixture of boric acid (boric acid) and sodium hydroxide (NaOH).

On the other hand, the pH of the CMP slurry for CoWP formation is characterized in that from 7 to 14, particularly preferably from 8 to 12 pH.

And it is characterized in that to maintain the temperature of the slurry at 80 ℃ to increase the formation rate of CoWP.

In the following, more specific embodiments based on the above embodiments will be described. However, the following embodiments are provided to facilitate the practice of the present invention, it is obvious that the scope of the present invention is not necessarily limited thereto.

1A to 1E are schematic views for explaining a method of forming an oxidation and diffusion barrier of a copper wiring for a semiconductor device according to an exemplary embodiment of the present invention.

First, referring to FIGS. 1A and 1B, a Si substrate 10 is prepared as a wafer, and 10000 nm silicon oxide film 20 is grown on the Si substrate through wet oxidation. As much as the silicon oxide film is removed through the photolithography and etching process, the portion C on which the copper wiring is to be formed is formed. Then, the Ta film 30 and the TaN film 40 serving as the diffusion barrier film were deposited to have a thickness of 500 kW and 300 kW, respectively, using PVD (Physical Vapor Deposition), and the copper film 60 was again deposited thereon through PVD. Deposit at a thickness of 9000 mm3.

Next, referring to FIG. 1C, an excess of 4500 kW of copper deposited using a slurry having an alumina abrasive is removed by a CMP process to form a copper interconnect 50. The composition and process conditions of the slurry for CMP used herein are shown in Table 1 below. At this time, de-ionized water is used as the main solvent. The same applies to the following.

Slurry composition abrasive Oxidant Corrosion inhibitor Complex former Kinds Alumina fruit tree 5-aminotetrazole citric acid Concentration 2.5 wt% 2 wt% 0.01M 0.02M CMP process conditions pressure Platen speed Head speed Slurry feed flow rate Condition 2.5 psi 80 rpm 75 rpm 150 mL / min

Next, referring to FIG. 1D, the copper surface is replaced with silver by using a CMP slurry for replacing the copper surface containing silver nitrate to form the silver thin film 70, which is an active layer required for CoWP deposition on the copper wiring 60. Replace. The composition and process conditions of the CMP slurry for copper surface substitution used here are shown in Table 2 below.

Slurry composition abrasive Oxidant Corrosion inhibitor Complex former A silver compound Kinds Silica fruit tree 5-aminotetrazole glycine Silver nitrate Concentration 0.5 wt% 1 wt% 0.01M 0.02M 0.1 wt% CMP process conditions pressure Platen speed Head speed Slurry feed flow rate Condition 1.5 psi 93 rpm 87 rpm 150 mL / min

Subsequently, referring to FIG. 1E, a CMP for forming CoWP, that is, a buffering step process after the CMP process for silver substitution, is supplied for 8 minutes while maintaining the CMP slurry for CoWP formation according to the present invention at 80 ° C. As it proceeds, a CoWP thin film 80 is formed on the silver thin film 70. Composition and process conditions based on 100ml CMP slurry for CoWP formation used herein are shown in Table 3 below.

Usage Kinds density Co source CoSO ₄ 2.0 g W source Sodium tungstate 2.5g Solution stabilizer 5-Aminotetrazole 0.01 g reducing agent Sodium hypophosphite 2.5g pH regulator Boric acid 6.18g NaOH 2.65 g Process conditions Slurry temperature 80 ℃ Slurry feed rate 150 mL / min Supply time 8 minutes

FIG. 2 is an X-ray diffraction analysis graph of a substrate surface for each step of a method of forming an oxidation and diffusion barrier layer of a copper wiring for a semiconductor device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, it can be seen that the copper wiring is replaced with silver to form a silver thin film, and a CoWP thin film is formed on the resultant. Therefore, it can be seen that the oxidation and diffusion barrier film is formed on the copper wiring only by a continuous CMP process without additional additional processes, ie, activation of the copper wiring using palladium.

As described above, according to the present invention, the oxidation and diffusion prevention film is formed on the copper wiring only by a continuous CMP process without additional additional processes, ie, activation of the copper wiring using palladium, thereby improving productivity and process efficiency.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

Claims (44)

Replacing the surface of the copper wiring for semiconductor device with silver by a chemical mechanical polishing process using a slurry for chemical mechanical polishing processes containing a silver compound; A chemical mechanical polishing process using a slurry for a chemical mechanical polishing process including a cobalt compound, a tungsten compound, and a phosphorus-containing reducing agent includes forming an oxidation and diffusion barrier layer on the surface substituted with silver. A method for forming an oxidation and diffusion barrier of copper wiring for semiconductor devices. The method of claim 1, wherein the slurry for the chemical mechanical polishing process containing the silver compound comprises an oxidizing agent, an abrasive, a corrosion inhibitor, a complex forming agent and a pH adjusting agent in the silver compound. Oxidation and diffusion barrier film formation method. The method of claim 2, wherein the oxidant is a peroxide-based oxidant. 4. The method of claim 3, wherein the peroxide oxidant is hydrogen peroxide. The method of claim 4, wherein the hydrogen peroxide is included in a range of 0.001 wt% to 30 wt%. The method of claim 5, wherein the hydrogen peroxide is included in a range of 0.001 wt% to 10 wt%. The method of claim 2, wherein the abrasive is at least one selected from the group consisting of alumina, silica, zirconia, ceria, titania, and germania. A method of forming an oxidation and diffusion barrier of a copper wiring for a semiconductor device. 8. The method of claim 7, wherein the abrasive has a size of 5 nm to 1000 nm. 8. The method for forming an oxide and diffusion barrier of a copper wiring for a semiconductor device according to claim 7, wherein the abrasive has a size of 10 nm to 500 nm. The method of claim 7, wherein the silica abrasive is included in a range of 0.01 wt% to 15 wt%. The semiconductor device according to claim 2, wherein the corrosion inhibitor is at least one selected from a tetrazole compound, a derivative substituted with an amine series, and a derivative substituted with an alkyl series. A method of forming an oxidation and diffusion barrier for copper wiring. 12. The method of claim 11, wherein the corrosion inhibitor includes 5-aminotetrazole (0.005 M to 0.5 M). The semiconductor device according to claim 2, wherein the complex forming agent is used by mixing at least one selected from carboxylic acid compounds and at least one selected from amino acid compounds. A method of forming an oxidation and diffusion barrier for copper wiring. The method of claim 13, wherein the carboxylic acid compound is acetic acid, formic acid, maleic acid, malic acid, tartaric acid, glutaric acid ), Citric acid (citric acid) and at least one selected from the group consisting of oxalic acid (oxalic acid), the amino acid compound is arginine (arginine), phenylalanine (phenyl alanine), glutamine (glutamine), glycine (glycine), glutamic acid (Glutamic acid) and serine (serine) at least any one selected from the group consisting of a copper wiring for a semiconductor device, the oxidation and diffusion prevention film forming method. The method of claim 13, wherein the complex forming agent is included in a range of 0.001M to 1M. 16. The method of claim 15, wherein the complex forming agent is included in a range of 0.005M to 0.5M. The method of claim 2, wherein the pH adjusting agent is any one selected from the group consisting of sulfuric acid, potassium hydroxide and ammonia water. The method of claim 2, wherein the silver compound is silver nitrate, silver (I) permanganate, silver chloride, silver iodide, silver phosphate, silver sulfate, silver carbonate, silver acetate, silver perchlorate, silver lactate, silver cyanide, silver (I) A method of forming an oxide and diffusion barrier film of a copper wiring for a semiconductor device, characterized in that at least one selected from the group consisting of selenide, silver (I) telluride, silver benzoate, silver thiocyanate, and potassium silver (I) cyanide. 19. The method of claim 18, wherein the silver compound is included in a range of 0.001 wt% to 20 wt%. 20. The method of claim 19, wherein the silver compound is included in a range of 0.005 wt% to 10 wt%. The method of claim 1, wherein the pH of the slurry for the chemical mechanical polishing process containing the silver compound is 7 to 14. 9. The method of claim 1, wherein the pH of the slurry for the chemical mechanical polishing process containing the silver compound is 9 to 13. According to claim 1, wherein the slurry for the chemical mechanical polishing process for forming the oxidation and diffusion barrier layer is characterized in that the complexing agent, slurry stabilizer and pH regulator are included in the reducing agent containing the cobalt compound, tungsten compound and phosphorus. A method of forming an oxidation and diffusion prevention film of a copper wiring for a semiconductor device. The method of claim 1, wherein the cobalt compound is CoSO ₄ . 25. The method of claim 24, wherein the CoSO ₄ is included in a range of 0.05 wt% to 20 wt%. The method of claim 25, wherein the CoSO ₄ is included in a range of 0.1 wt% to 15 wt%. The method of claim 1, wherein the tungsten compound is sodium tungstate. 28. The method of claim 27, wherein the sodium tungstate is included in a range of 0.01 wt% to 20 wt%. 29. The method of claim 28, wherein the sodium tungstate is included in the range of 0.1 wt% to 15 wt%. 24. The method of claim 23, wherein the complex forming agent is a citrate series. 31. The method of claim 30, wherein the citrate is sodium citrate. 32. The method of claim 31, wherein the sodium citrate is included in a range of 0.5 wt% to 50 wt%. 33. The method of claim 32, wherein the sodium citrate is included in the range of 1 wt% to 30 wt%. The semiconductor as claimed in claim 23, wherein the slurry stabilizer is a derivative of a tetrazole compound substituted with an amine or a derivative of a tetrazole compound substituted with an alkyl. A method for forming an oxidation and diffusion barrier of copper wiring for a device. 35. The method of claim 34, wherein the slurry stabilizer comprises 5-aminotetrazole. 36. The method of claim 35, wherein the 5-aminotetrazole is included in the range of 0.001 wt% to 5 wt%. The method of claim 36, wherein the 5-aminotetrazole is included in a range of 0.005 wt% to 3 wt%. The method of claim 1, wherein the phosphorus-containing reducing agent is a hypophosphite series. 39. The method of claim 38, wherein the phosphorus-containing reducing agent is sodium hypophosphite. 40. The method of claim 39, wherein the sodium hypophosphite is included in a range of 0.1 wt% to 30 wt%. 41. The method of claim 40, wherein the sodium hypophosphite is included in a range of 0.5 wt% to 20 wt%. 24. The method of claim 23, wherein the pH adjusting agent is a mixture of boric acid and sodium hydroxide (NaOH). The method of claim 1, wherein the pH of the slurry for the chemical mechanical polishing process for forming the oxidation and diffusion barrier layer is 7-14. 44. The method of claim 43, wherein the pH of the slurry for the chemical mechanical polishing process for forming the oxidation and diffusion barrier layer is 8 to 12.

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