KR100970094B1 - CMP slurry composition for polishing copper line and polishing method using the same - Google Patents

Abstract

The present invention relates to a CMP slurry composition for copper wiring polishing and a polishing method using the same, and more particularly, to deionized water using a solvent, oxidizing agents, organic acids, corrosion inhibitors and metal oxides having a specific particle size and association degree for polishing purposes. The present invention relates to a CMP slurry composition which can be selectively used to control the polishing rate for copper wirings, barrier films, and insulating films, thereby minimizing erosion and dishing and improving storage stability of the slurry composition. .

According to the present invention, it is possible to provide a copper wiring polishing CMP slurry composition and a polishing method using the same, in which erosion and dishing are minimized and storage stability of the slurry composition is improved.

Copper, wiring, polishing, CMP, slurry, particle size, association degree, barrier film, insulating film, erosion, dishing, storage stability

Description

CMP slurry composition for polishing copper line and polishing method using the same}

The present invention relates to a CMP slurry composition for polishing a metal film of a semiconductor conductive layer, and more particularly, to a CMP slurry composition for polishing a metal film formed of copper (Cu) and a polishing method using the same.

In the CMP process, the surface of a wafer is planarized using a polishing pad and a slurry composition during semiconductor manufacturing. The polishing agent is brought into contact with the polishing pad and the wafer, and the polishing pad and the wafer are subjected to an orbital motion in which rotation and linear motions are mixed. It is a process of polishing using a slurry composition containing. The slurry composition used in the CMP process is composed of a compound such as an abrasive which has a large physical action and an etchant which has a chemical action. Therefore, the slurry composition selectively etches portions exposed to the wafer surface by physical and chemical action to perform a more optimized and extensive planarization process.

It is very important to control the polishing rate for dissimilar films in copper wiring polishing. When polishing the copper wiring, the polishing target includes not only the copper wiring but also a barrier film and an insulating layer. At this time, the polishing performance depends on the polishing rate for the copper wiring and the difference in polishing rates for the two other films.

Copper wire polishing is generally divided into three stages, with different requirements for each stage. The first copper copper step is to remove excess copper quickly. In the second soft landing step, copper must be removed while the barrier and insulating film must be able to resist. That is, the polishing selectivity for copper wiring and heterogeneous film quality should be high. In this case, if the polishing rate of the barrier layer and the insulating layer is high, erosion and dishing become large, resulting in a defect of the device and a low process margin, thereby making it difficult to realize uniform polishing performance. In the third polishing step, the polishing rate for copper wiring is lowered compared to the first and second polishing steps, and the polishing rate for the barrier film and the insulating film is increased. It should be polished equally and evenly. That is, the polishing selectivity for copper wiring and heterogeneous film quality should be low. This is to remove the erosion and dishing generated in the second polishing step and to completely remove copper residues. If the polishing rate for the barrier film and the insulating film is low, the erosion and dishing occurred in the second step are removed. You will not be able to improve.

In general, the first polishing step and the second polishing step use the same bulk copper slurry composition as the polishing step at the time of polishing, and the third step is different from the previous step. Polishing is carried out using a barrier slurry composition.

Previously used copper wiring slurry compositions mainly used a method of controlling the polishing rate for dissimilar films using additives such as polymer compounds (US6,616,717, US6,679,928, US6,699,299, JP2001-144046A). The technique using the polymer compound had the effect of controlling the polishing rate for the insulating film, but had the disadvantage of inhibiting the stability of the slurry composition. In addition, since the polymer compound increases the viscosity of the entire slurry composition, there is a problem in the uniform supply of the slurry composition, such as an air bubble (bubble) generated during the transfer of the slurry composition, and in addition, some polymer on the wafer surface after polishing Has the disadvantage of degrading the performance of the device by adsorption.

Accordingly, the present invention can easily control the polishing rate for the copper wiring, the barrier film and the insulating film, and can improve erosion and dishing without side effects caused by organic residues such as polymers, and improve the storage stability of the slurry composition. To provide a CMP slurry composition for.

The present invention provides a copper wiring polishing slurry composition comprising ultrapure water, an abrasive, an organic acid, an oxidizing agent, and a corrosion inhibitor, wherein the bulk copper polishing slurry composition has an average value of primary particle diameter of 1 to 30 nm and a particle association degree of 3 or less. The slurry composition for barrier polishing contains the abrasive | polishing agent, The average value of primary particle diameters is 30-100 nm, and provides the slurry for copper wiring polishing containing the abrasive | polishing agent whose particle | grain association degree is 3 or less.

The abrasive is characterized in that the silica.

The average value of the primary particle diameter of the abrasive of the slurry of the bulk copper polishing slurry composition is 10 to 30 nm, the average value of the primary particle diameter of the abrasive of the slurry composition for barrier polishing is characterized in that 30 to 80 nm.

 The particle association degree of the said abrasive is 2.5 or less, It is characterized by the above-mentioned.

 The content of the abrasive is characterized in that 0.05 to 30% by weight relative to the entire bulk copper slurry polishing composition or the barrier polishing slurry composition.

 The abrasive content in the bulk copper polishing slurry composition is 0.05 to 10 wt% based on the total slurry composition, and the abrasive content in the barrier polishing slurry composition is 1 to 20 wt%.

The organic acid is characterized in that at least one substance selected from the group consisting of carbonyl compounds and salts thereof, carboxylic acid compounds and salts, alcohols, amine-containing compounds.

The organic acid is characterized in that the dicarboxylic acid and salts thereof.

The content of the organic acid is characterized in that 0.01 to 10% by weight based on the total slurry composition.

The oxidizing agent is inorganic or organic per-compounds, bromic acid and salts thereof, nitric acid and salts thereof, chloric acid and salts thereof, chromic acid and salts thereof, iodic acid and salts thereof, iron and salts thereof, copper and salts thereof At least one material selected from the group consisting of rare earth metal oxides, transition metal oxides, red blood salts and potassium dichromate.

The content of the oxidizing agent is characterized in that 0.01 to 30% by weight based on the total slurry composition.

The corrosion inhibitor is characterized in that at least one material selected from the group consisting of ammonia (alkylamines), amino acids (amino acids), imines (azoles), and azoles (azoles).

The corrosion inhibitor is characterized in that the compound containing benzotriazole and its derivatives.

The corrosion inhibitor is 2,2 '-[[5-methyl-1H-benzotriazol-1-yl] methyl] imino] bis-ethanol (2,2'-[[(5-methyl-1H-benzotriazole- 1-yl) -methyl] imino] bis-ethanol) isomeric mixture (isomeric mixture).

The corrosion inhibitor is characterized in that 0.001 to 2% by weight based on the total slurry composition.

The slurry composition is characterized in that it further comprises a pH adjuster.

PH of the slurry composition is characterized in that 2 to 4.

Further, in the present invention, using the bulk copper polishing slurry composition, the first and second polishing step for the copper wiring, and the third polishing step for the copper wiring using the slurry composition for polishing the barrier. A copper wiring polishing method is provided.

The composition of the present invention provides a slurry composition which minimizes erosion and dishing during copper wire polishing and improves storage stability of the slurry composition.

The present invention provides a copper wiring polishing slurry composition comprising ultrapure water, an abrasive, an organic acid, an oxidizing agent, and a corrosion inhibitor, wherein the bulk copper polishing slurry composition has an average value of primary particle diameter of 1 to 30 nm and a particle association degree of 3 or less. The slurry composition for barrier polishing contains the abrasive | polishing agent, Comprising: The average value of primary particle diameters is 30-100 nm, It is related with the copper wiring polishing slurry composition characterized by including the abrasive | polishing agent whose particle | grain association degree is 3 or less.

As the abrasive, fine metal oxide powders such as silica (SiO 2), alumina (Al 2 O 3), zirconia (ZrO 2), ceria, and molybdenum oxide may be used. Among them, it is more preferable to use silica, and most preferably, it is effective to use colloidal silica.

The size of the abrasive depends on the application purpose. In other words, in order to obtain a low polishing rate for the barrier film and the insulating film, the average value of the primary particle diameter should be 30 nm or less, whereas in order to obtain a high polishing rate for the barrier film and the insulating film, the average value of the primary particle diameter should be 30 nm or more. In the copper wire polishing slurry composition, when the average amount of primary particle size is more than 30 nm, the polishing rate of barrier and insulating film is too high, so the erosion is large and the process time must be shortened to overcome this. Residues are generated and the failure rate is high. In addition, the barrier composition used in the third polishing step (barrier polishing), when the average particle size of the abrasive is less than 30nm, the polishing selectivity between the copper and the dissimilar film increases, the excess polishing time will be longer The more erosion and dishing is intensified.

The average primary particle diameter of the abrasive in the bulk copper polishing slurry composition is preferably 1 to 30 nm in view of high polishing rate for copper wiring and high polishing selectivity for copper wiring and dissimilar film quality, and more preferably 5 It is effective that it is-30 nm, most preferably 10-30 nm. In addition, the average particle diameter of the abrasive in the barrier polishing slurry composition is preferably 30 to 120 nm from the viewpoint of low polishing selectivity, storage stability, and scratch resistance for copper wiring and heterogeneous film quality, and more preferably 30 It is effective that it is ˜100 nm, most preferably 30 to 80 nm.

As is widely known, the diameter of a metal oxide may be viewed by dividing it into a primary particle size or a secondary particle size. The primary particle size refers to the size of the metal oxide individual particles measured before the slurry composition is prepared, and the secondary particle size refers to the size of the particle group measured after the slurry composition is prepared. In this case, the ratio between the primary particle size (d1) and the secondary particle size (d2) is referred to as the degree of association (d2 / d1, aggregate ratio, d2 / d1≥1) .This value should not exceed 3 for uniform polishing performance. It is more preferable that the association degree is 2.5 or less.

This is common to both the bulk copper polishing slurry composition and the barrier polishing slurry composition. If the degree of association of the abrasive to be used exceeds 3, the stability of the slurry composition is lowered, resulting in poor polishing performance and poor polishing reproducibility. .

The amount of the abrasive is preferably 0.05 to 30% by weight relative to the entire bulk copper polishing slurry composition or the barrier polishing slurry composition in terms of appropriate polishing rate and dispersion stability, and the abrasive in the bulk copper polishing slurry composition. It is more preferable that the content of is 0.05 to 10% by weight, and the content of the abrasive in the barrier polishing slurry composition is 1 to 20% by weight.

The organic acid used in the present invention is a material that chelates the copper oxide oxidized by the oxidizing agent, and serves to increase the polishing rate and prevent resorption of the metal oxide to reduce defects. The organic acid is a carbonyl compound and salts thereof, carboxylic acid compounds and salts thereof (carboxylic acid compounds and salts thereof containing at least one hydroxyl group, dicarboxylic acids and salts thereof, tricarboxylic acids and salts thereof, polycarboxylic acids and salts thereof, one or more sulfonic acid groups And / or (a) carboxylic acid compounds containing phosphoric acid groups and salts thereof), alcohols (dialcohol, trialcohol, polyalcohol, etc.), amine-containing compounds, and the like, which may be used alone or in combination of two or more. Preferably, carboxylic acid compounds and salts thereof may be used, and more preferably dicarboxylic acids and salts thereof, such as malic acid, malonic acid, maleic acid, and salts thereof, and most preferably Preferably, dicarboxylic acids and salts thereof containing at least one hydroxyl group such as malic acid can be used.

The content of the organic acid is preferably 0.01 to 10% by weight based on the total slurry composition, in order to obtain an appropriate polishing rate and dispersion stability and to reduce corrosion or pitching during polishing. Preferably from 0.05 to 5% by weight can be used.

The oxidizing agent used in the present invention serves to oxidize and polish metal surfaces, and examples thereof include inorganic or organic per-compounds, bromic acid and salts thereof, nitric acid and salts thereof, chloric acid and salts thereof, and chromic acid. And salts thereof, iodic acid and salts thereof, iron and salts thereof, copper and salts thereof, rare earth metal oxides, transition metal oxides, red blood salts, potassium dichromate and the like. Most preferably hydrogen peroxide can be used.

The amount of the oxidizing agent is preferably 0.01 to 30% by weight, more preferably 0.05 to 20% by weight, based on the total slurry composition in terms of obtaining an appropriate polishing rate and reducing corrosion or pitching during polishing. It may be used, most preferably from 0.1 to 10% by weight.

Corrosion inhibitor used in the present invention is a material that delays the chemical reaction of the oxidizing agent to inhibit the corrosion in the low step area where physical polishing does not occur, and in the high step area where polishing takes place so that polishing can be performed by removing the physical action of the abrasive. Acts as a polishing regulator. As corrosion inhibitors, nitrogen-containing compounds are mainly used. Examples include ammonia, alkylamines, amino acids, imines, and azoles. These may be used alone or in combination of two or more. Preferably, a compound containing a cyclic nitrogen compound and a derivative thereof may be used, and more preferably, a compound containing benzotriazole and a derivative thereof may be used, and most preferably 2,2 ' -[[5-methyl-1H-benzotriazol-1-yl] methyl] imino] bis-ethanol (2,2 '-[[(5-methyl-1H-benzotriazole-1-yl) -methyl] imino ] isomeric mixtures of bis-ethanol) can be used.

The content of the corrosion inhibitor is preferably 0.001 to 2% by weight based on the total slurry composition in terms of achieving a corrosion inhibitory effect, obtaining an appropriate polishing rate, and preventing slurry stability deterioration, and more preferably 0.01 to 1% by weight. have.

In addition, in order to secure the polishing performance of the CMP slurry composition, the pH of the CMP slurry composition may be adjusted to 2 to 4 using an acidic substance such as nitric acid, sulfuric acid, phosphoric acid, hydrochloric acid, or a basic substance such as KOH or TMAH.

The bulk copper polishing slurry composition of the present invention is used to quickly remove excess copper in the first polishing step, and in the second polishing step, using the same bulk copper polishing slurry composition as the first polishing step, but by lowering the polishing pressure. While the copper is removed, the barrier and insulating film are not removed, and in the third polishing step, the barrier polishing slurry composition of the present invention is used to remove erosion and dishing generated in the barrier and insulating film in the second polishing step, and the copper residue The water can be removed completely.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are only for the purpose of description and should not be construed as limiting the scope of the present invention.

Example 1

The bulk copper polishing slurry composition was prepared to contain 10 g of abrasive, 5 g of malic acid of Table 2, 5 g of corrosion inhibitor of Table 2, and 950 g of deionized water using ST-O of Table 1, and the pH was adjusted to 2.1 using nitric acid. It was. 30 g of hydrogen peroxide was mixed into the composition just before polishing, followed by stirring for 1 minute, and then the first polishing and the second polishing were performed in the following conditions. Thereafter, the slurry composition for barrier polishing was used to include 100 g of abrasive, 4 g of malic acid of Table 2, 1 g of corrosion inhibitor of Table 2, and 877 g of deionized water using PL-3 of Table 1, and pH to be 2.1 using nitric acid. Fit. 18 g of hydrogen peroxide was mixed into the composition just before polishing, followed by stirring for 1 minute, followed by tertiary polishing under the conditions shown in Table 3. The polishing results for each step are shown in Table 4.

[Examples 2 to 3 and Comparative Examples 1 to 3]

After the slurry composition was prepared in the same manner as in Example 1 using the abrasive particles as shown in Table 1 and the composition having the composition as shown in Table 2, primary, secondary, and tertiary polishing were performed under the same polishing conditions as in Example 1. It progressed, and the result is shown in Table 4.

 ※ Abrasive Information

    ㆍ ST-O: Nissan, average 15nm of primary particle size

    ㆍ PL-3: Fuso, average 35nm of primary particle size

    ㆍ PL-7: Fuso, average 70nm of primary particle size

    ㆍ Ludox HAS: Grace, average 12nm of primary particle size

※ Malic acid: Samjeon Chemical, 99%, DL-Malic acid

   Corrosion inhibitor: Ciba Chemical, product name Irgamet42, 70%

                isomeric mixture of 2,2 '-[[(5-methyl-1H-benzotriazole-1-yl)-

                methyl] imino] bis-ethanol

Polishing condition

o Grinder Model: Mirra (AMAT)

o Process conditions:

    -Pad type: IC1000 / SubaIV Stacked (Rodel)

    -Temperature: 25 ℃

  o Polishing target: 8-inch copper, PE-TEOS blanket wafer

               8 inch copper pattern wafer (854CMP200, ATDF)

   ＊: Phenomenon that the insulating film is exposed due to the grinding of the barrier film after the second polishing

   ※ Location of erosion measurement: 0.18㎛, 50% density,

      Dishing position: 100㎛ Line

  In the case of using abrasive particles suitable for each polishing step, the dishing and erosion values after the final polishing were low, but the dishing and erosion values were high when the particles were not suitable even in one step.

[Examples 4 to 6 and Comparative Examples 4 to 6]

Using the particles of Table 5 and the composition of Table 2, except that no hydrogen peroxide was added to prepare a slurry composition in the same manner as in Example 1, storage stability at room temperature was measured and the results are shown in Table 6. Indicated.

 ※ Abrasive Information

    ㆍ ST-O: Nissan, average 15nm of primary particle size

    ㆍ PL-3: Fuso, average 35nm of primary particle size

    ㆍ Ludox HAS: Grace, average 12nm of primary particle size

    ㆍ Levasil 100s / 30: H.C. Starck, average 30nm of primary particle size

    ㆍ Levasil 200s / 30: H.C. Starck, average 15nm of primary particle size

    ㆍ Ludox CL-P: Grace, average 20nm of primary particle size

   ※ Association degree = average of secondary particle size / average of primary particle size after slurry production

      N.S. : Not Settled

      S.: Settled

When the degree of association of the abrasive grains exceeds 3, it was confirmed that the storage stability at room temperature is very weak.

Claims (18)

In the polishing method of copper wiring, 0.05 to 10% by weight abrasive, 0.01 to 10% by weight of organic acid, 0.01 to 30% by weight of oxidizing agent, 0.001 to 2% by weight of corrosion inhibitor and extra ultrapure water having an average particle diameter of 1 to 30 nm and particle association of 3 or less Polishing the copper film using the bulk copper polishing slurry composition; And 1 to 20% by weight abrasive, 0.01 to 10% by weight of organic acid, 0.01 to 30% by weight of oxidant, 0.001 to 2% by weight of corrosion inhibitor and extra ultrapure water having an average value of primary particle diameter of 35 to 100 nm and particle association of 3 or less Polishing the barrier film and the insulating film using the barrier polishing slurry composition To include, wherein the bulk copper polishing slurry composition and the barrier polishing slurry composition does not contain a polymer compound. delete According to claim 1, wherein the average value of the primary particle diameter of the abrasive of the slurry slurry composition for bulk copper polishing is 10 to 30nm, the average value of the primary particle diameter of the abrasive of the slurry composition for barrier polishing is 35 to 80nm. Polishing method. The polishing method according to claim 1, wherein the degree of particle association of the abrasive in the bulk copper polishing slurry composition and the barrier polishing slurry composition is independently 2.5 or less. delete delete The method of claim 1, wherein the organic acid in the bulk copper polishing slurry composition and barrier polishing slurry composition are each independently selected from the group consisting of a carbonyl compound and its salt, a carboxylic acid compound and its salt, alcohols, and an amine-containing compound Polishing method, characterized in that at least one material. delete delete The method of claim 1, wherein the oxidizing agent in the bulk copper polishing slurry composition and barrier polishing slurry composition are each independently inorganic or organic per-compounds, bromic acid and salts thereof, nitric acid and salts thereof, chloric acid and At least one substance selected from the group consisting of salts, chromic acid and salts thereof, iodic acid and salts thereof, iron and salts thereof, copper and salts, rare earth metal oxides, transition metal oxides, red blood salts, and potassium dichromate. Polishing method. delete The method of claim 1, wherein the corrosion inhibitor in the bulk copper polishing slurry composition and the barrier polishing slurry composition are each independently ammonia, alkylamines, amino acids, imines And at least one substance selected from the group consisting of azoles. delete delete delete delete delete delete