KR101943704B1 - Cmp slurry composition for metal film and polishing method - Google Patents

Abstract

The CMP slurry composition for a metal film of the present invention comprises abrasive particles, a solvent, an oxidizing agent, a metal ion and a reducing agent.

Description

Technical Field [0001] The present invention relates to a CMP slurry composition for a metal film,

The present invention relates to a CMP slurry composition for a metal film and a polishing method.

BACKGROUND ART In manufacturing semiconductor devices, a CMP process is applied to planarize a wafer surface, an insulating layer on a wafer, or a metal film layer. The CMP process is a step of planarizing a film to be polished by using a polishing pad and a slurry composition. The polishing pad is brought into contact with a surface to be polished, and then a polishing slurry is flowed between the polishing pad and the polishing target, Orbital motion in which the pad is rotated and linear motion is mixed.

However, in the CMP process, defects or dishing occur due to excessive polishing or etching during the process of planarizing an object to be polished. In order to solve this problem, it has been attempted to adjust the characteristics of the abrasive grains or to improve the abrasive grains by surface treatment.

Therefore, development of a new CMP slurry composition capable of remarkably reducing occurrence of defects such as scratches or dishing is required.

Prior art related to this is disclosed in Korean Patent Publication No. 2006-0007028.

It is an object of the present invention to provide a CMP slurry composition and a polishing method for a metal film that can minimize scratches and dishing.

Another object of the present invention is to provide a CMP slurry composition and a polishing method for a metal film capable of self-repairing scratches and dishing.

The above and other objects of the present invention can be achieved by the present invention described below.

One aspect of the present invention relates to a CMP slurry composition for a metal film.

In one embodiment, the CMP slurry composition for a metal film includes abrasive particles, a solvent, an oxidizing agent, a metal ion, and a reducing agent.

The metal ion is monovalent copper ion (Cu ^+), divalent copper ion (Cu ^{2 +),} silver ions (Ag ^+), the family of cobalt ions (Co ^+), divalent cobalt ions (Co ^{2 +),} refrain from cobalt ion (Co ^{3 +} ), monovalent nickel ion (Ni ⁺ ), and bivalent nickel ion (Ni ^{2 +} ).

The reducing agent may include at least one of ascorbic acid, glycolic acid, formaldehyde, hypophosphite, hydrazine, and dimethylamine borane.

In another embodiment, the composition may further comprise an organic additive.

The organic additive is selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), ethylene glycol-propylene glycol copolymer (PEG-PPG), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), cetyltrimethylammonium pro 3-N, N-dimethylaminodithiocarbamoyl-1-propanesulfonic acid (DPS), bis (3-sulfopropyl) disulfide (SPS), dodecyltrimethylammonium bromide , 3-mercapto-1-propanesulfonic acid (MPSA), and 2-mercapto-5-benzimidazolesulfonic acid (MBIS).

In another embodiment, the composition may further comprise at least one of a corrosion inhibitor, a pH adjusting agent and a complexing agent.

The composition may include 1 mM to 300 mM of the metal ion.

The composition may include 1 mM to 200 mM of the reducing agent.

The composition may contain 0.01 to 10% by weight of the oxidizing agent.

The composition may have a molar ratio of the oxidizing agent to the reducing agent of from 1: 1 to 10: 1.

The composition may have a molar ratio of the reducing agent to the organic additive of 2: 1 to 50: 1.

The number of scratches may be less than 10 when polishing the metal film for 30 seconds at a pressure of 2.2 psi using the above composition.

When the metal film is polished for 30 seconds at a pressure of 2.2 psi using the above composition, the dishing may be 1200 Å or less.

Another aspect of the invention relates to a polishing method.

In one embodiment, the polishing method comprises polishing the metal film with a CMP slurry composition for a metal film and at the same time self-repairing, wherein the CMP slurry composition for a metal film comprises abrasive particles, a solvent, an oxidant, a metal ion and a reducing agent , And the self-repair may be such that the metal ions are precipitated on the metal film by the reducing agent to form a plating layer.

The self-repair may be electroless plating.

The present invention has the effect of providing a CMP slurry composition and a polishing method for a metal film that can minimize scratches and dishing, and can self-repair scratches and dishing.

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

In the following description of the present invention, detailed description of known related arts will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured by the present invention.

In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

Also, in interpreting the constituent elements, even if there is no separate description, it is interpreted as including the error range.

In the present specification, 'X to Y' representing the range means 'X or more and Y or less'.

In the present specification, 'scratch' can be measured by polishing the entire 300 mm wafer using LS6800 manufactured by HITACHI after polishing using the CMP slurry composition for a metal film under the following measurement conditions.

In the present specification, 'dishing' can be performed by polishing the CMP slurry composition for a metal film under the following measurement conditions, and then calculating the dishing by measuring the profile of the pattern using XE-300 manufactured by Park Systems.

[Measuring conditions]

- Polishing rate measurement wafer: 300mm Cu Blanket wafer

- Polishing equipment: Reflexion LK 300 mm (AMAT)

- Polishing pad: WVP6000 (Nextplanar)

- Polishing time: 30s

- Pressure: 2.2 psi

- Platen rpm: 98 rpm

- Head rpm: 87 rpm

- Flow rate: 250 ml / min

The CMP slurry composition for a metal film of the present invention comprises abrasive particles, a solvent, an oxidizing agent, a metal ion and a reducing agent.

Abrasive particle

The abrasive grains are for generating a physical abrasive action, and abrasive grains generally used in the art can be used, and are not particularly limited.

For example, as the abrasive particles such as silica (SiO _2), alumina (Al ₂ O _3), ceria (CeO _2), zirconia (ZrO _2), titania (TiO _2), and molybdenum oxide (MoO ₃₎ A fine metal oxide may be used. Of these, silica can be used in that the dispersion stability of the slurry composition is excellent and scratches are less generated during polishing. The abrasive grains may be used alone or in combination of two or more.

The abrasive grains may be contained in the slurry composition in an amount of 0.001 to 20 wt%, specifically 0.001 to 10 wt%, more specifically 0.01 to 5 wt%. Within this range, the polishing rate for the metal film and the dispersion stability of the slurry composition are excellent.

menstruum

The solvent is for preparing the CMP slurry composition in a slurry state, for example, water, and preferably it may be deionized water.

Oxidant

The oxidizing agent serves to chemically etch the surface of a metal film, for example, a copper film to be polished. In the present invention, the oxidizing agent may be at least one selected from the group consisting of inorganic or organic per-compounds, bromic acid or its salt, nitric acid or its salt, chloric acid or its salt, chromic acid or its salt, iodic acid or its salt, Oxides, transition metal oxides, red blood salts, potassium bichromate and the like can be used. For example, hydrogen peroxide may be used as the oxidizing agent.

The oxidizing agent may be added in an amount of 0.01 to 10% by weight based on the total slurry composition, specifically 0.01 to 5% by weight. Alternatively, in an embodiment, the oxidizing agent may be included in the slurry composition at 1 mM to 100 mM, specifically 2 mM to 50 mM. It is possible to obtain an appropriate polishing rate for the metal film within the above range and to reduce the corrosion and pitting phenomenon at the time of polishing.

Metal ion

Metal ions are plated in defects or dishing caused by excessive polishing or etching during the CMP process, and play a role of self-repairing the defects or dishing. Specifically, the metal ions combine with the electrons generated by the reducing agent to deposit on the metal film, so that the metal film can be repaired and recovered by itself.

However, the CMP slurry composition of the present invention contains a metal ion and a reducing agent, so that a defect or dishing that has already occurred can be repaired and restored by self-repair, Can be minimized.

The plating may be electroless plating with a metal ion and a reducing agent. In the case of applying electroless plating, there is no need to apply a voltage and no additional equipment is required, and the plating is uniform.

The metal film may be copper, silver, cobalt, nickel, or the like, and the metal ion may be the same metal as the metal to be polished, but is not limited thereto. For example, the metal ion is monovalent copper ion (Cu ^+), divalent copper ion (Cu ^{2 +),} silver ions (Ag ^+), the family of cobalt ions (Co ^+), divalent cobalt ions (Co ^{2 +),} refrain cobalt ions (Co ^{+ 3),} monovalent nickel ions (Ni ⁺⁾ and teeth but may include one or more of nickel ions (Ni ^{+ 2),} but is not limited thereto.

Particularly, the present invention has advantages of simple CMP process and self-repairing simultaneously by including metal ions in the CMP slurry composition without performing any self-repair.

In embodiments, the metal ion may be included in the slurry composition in salt form. For example, the metal ion may be included in the slurry composition in the form of a metal chloride, a metal nitrate or a metal sulfide, but is not limited thereto.

The metal ion may be added to the slurry composition at 1 mM to 300 mM, specifically 20 mM to 100 mM. Within this range, there is an advantage that the self-repairing property can be exhibited optimally without affecting the CMP process.

reducing agent

The reducing agent serves to provide electrons so that metal ions can be plated on the metal film.

Specifically, the reducing agent includes at least one of ascorbic acid, glycolic acid, formaldehyde, hypophosphite, hydrazine, and dimethylamine borane. can do. In view of the ease of controlling the plating rate, at least one of ascorbic acid and glycolic acid may be used as the reducing agent.

The reducing agent may be contained in the slurry composition in an amount of 1 mM to 200 mM, specifically 1 mM to 100 mM. The reducing agent may be contained in the slurry composition in an amount of 0.1 to 10% by weight, specifically 0.01 to 5% by weight, more particularly 0.01 to 1% by weight. Within the above range, there is an advantage that the precipitation of metal ions is optimized without affecting the CMP process.

In embodiments, the composition may have a molar ratio of oxidizing agent to reducing agent of from 1: 1 to 10: 1, specifically from 1: 1 to 5: 1. Within the above-mentioned range, the balance between the polishing of the metal film and the self-repair is excellent.

Organic additive

In another embodiment, the slurry composition of the present invention may further comprise an organic additive. The organic additive can slow down or accelerate the plating rate, and controls the dishing by adjusting the plating amount in the concave portion of the metal.

The organic additive may include at least one of a non-ionic additive, an ionic additive, and a sulfur-containing additive.

Specifically, the organic additive may be selected from the group consisting of polyethyleneglycol (PEG), polypropylene glycol (PPG), ethylene glycol-propylene glycol copolymer (PEG-PPG), polyvinylpyrrolidone (PVP) Warming additives; Ionic additives such as cetyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB); 1-propanesulfonic acid (DPS), 3-mercapto-1-propanesulfonic acid (MPSA), and 3-mercapto- And sulfur-containing additives such as 2-mercapto-5-benzimidazole disulfonic acid (MBIS).

For example, the organic additive may include one or more of polyethylene glycol (PEG) and bis (3-sulfopropyl) disulfide (SPS) in terms of plating rate and uniformity.

When the organic additive is included, the content of the organic additive may be in the range of 0.001 to 10 mM, specifically 0.01 to 5 mM, by weight in the slurry composition. In the above range, there is an advantage that the self-repairing property by plating is maximized.

In embodiments, the molar ratio of the reducing agent to the organic additive may be 2: 1 to 50: 1, specifically 5: 1 to 40: 1, more specifically 10: 1 to 30: 1. Within the above range, the balance between the CMP polishing process and self-repairing is excellent.

Corrosion inhibitor

In yet another embodiment, the slurry composition may further comprise a corrosion inhibitor. The corrosion inhibitor is a polishing agent capable of retarding a chemical reaction of an oxidizing agent to inhibit corrosion in a low step region in which physical polishing does not occur and being removed by a physical action of the abrasive particles in a high step region where polishing occurs, .

As the corrosion inhibitor, a nitrogen-containing compound can be used, and examples thereof include ammonia, alkyl amines, amino acids, imines, azoles, and the like. These may be used alone or in combination of two or more.

The corrosion inhibitor is more effective than the compound containing a cyclic nitrogen compound and a derivative thereof, and includes benzoquinone, benzyl butyl phthalate, and benzyl-dioxolane. Can be used.

Among them, triazole compounds such as 1,2,3-triazole, 1,2,4-triazole, benzotriazole and the like, tetrazole compounds such as aminotetrazole and the like or mixtures thereof can be used.

The corrosion inhibitor may be included in the slurry composition in an amount of 1 to 50 mM, specifically 1 to 30 mM, more specifically 3 to 20 mM. Within this range, excellent corrosion inhibiting effect and appropriate polishing rate can be obtained.

pH adjusting agent

In yet another embodiment, the slurry composition may further comprise a pH adjusting agent. The pH adjusting agent controls the dispersion degree of the abrasive grains by controlling the pH of the slurry composition.

The pH adjusting agent may be an acid or a base without limitation, for example, ammonia, ammonium methyl propanol (AMP), tetramethyl ammonium hydroxide (TMAH), potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, Sodium carbonate, sodium carbonate, sodium carbonate, triethanolamine, tromethamine, niacinamide, nitric acid, sulfuric acid, phosphoric acid, hydrochloric acid, acetic acid, citric acid, glutaric acid, gluconic acid, formic acid, lactic acid, malic acid, malonic acid, , Succinic acid, and tartaric acid.

The pH adjusting agent may be contained in the slurry composition in an amount of 0.01 to 1% by weight, specifically 0.05 to 0.5% by weight. In the above range, the degree of dispersion of abrasive grains is excellent, and occurrence of scratches can be prevented.

Complexing agent

In another embodiment, the slurry composition may further comprise a complexing agent. The complexing agent serves to chelate the metal oxide oxidized by the oxidizing agent. That is, it is intended to suppress the re-adsorption of the oxidized metal oxide by the chelate reaction with the metal oxide to the metal film layer to be polished, to increase the polishing rate for the metal film and to reduce surface defects.

In the present invention, as the complexing agent, organic acids or salts thereof, amino acids or salts thereof, alcohols such as dialcohols, trihydrates and polyalcohols, amine-containing compounds, etc. may be used alone or in combination. For example, there can be mentioned ammonium acetate, ammonia oxalate, ammonium formate, ammonium tartrate, ammonium lactate, glycine, alanine, serine, aspartic acid, glutamic acid, proline Aminobutyric acid, aminobutyric acid, aminobutyric acid, aminobutyric acid, aminobutyric acid, aminobutyric acid, aminobutyric acid, aminobutyric acid, aminobutyric acid, ), Aminoethylaminoethanol, aminopyridine; A carboxylic acid compound or a salt thereof, a carboxylic acid compound or a salt thereof, a carboxylic acid compound or a salt thereof, a carboxylic acid compound or a salt thereof containing at least one hydroxyl group, a dicarboxylic acid or a salt thereof, a tricarboxylic acid or a salt thereof, a polycarboxylic acid (e.g. ethylenediaminetetraacetic acid, EDTA ) Or a salt thereof, a carboxylic acid compound containing at least one sulfonic acid group or (a) phosphoric acid group, or a salt thereof, and the like, but is not limited thereto. These may be used alone or in combination of two or more.

The complexing agent may be contained in the slurry composition in an amount of 10 to 500 mM, specifically 50 to 200 mM. Within the above range, the polishing rate, the dispersion stability of the slurry, and the surface characteristics of the object to be polished are excellent, and the effect of wafer outer profile improvement and wide-area planarization is obtained.

The slurry composition according to the present invention may further contain a surfactant, a modifier, a polymer compound, a dispersing agent and the like in addition to the above-mentioned components.

In embodiments, the number of scratches may be less than 10 when polishing the metal film for 30 seconds at a pressure of 2.2 psi using the composition.

In another embodiment, the dishing may be less than or equal to 1200 angstroms, for example, from 800 angstroms to 1200 angstroms, specifically from 800 angstroms to 1,000 angstroms, when polishing the metal film for 30 seconds at a pressure of 2.2 psi using the composition.

Another aspect of the invention relates to a polishing method.

In one embodiment, the polishing method comprises polishing the metal film with a CMP slurry composition for a metal film and at the same time self-repairing, wherein the CMP slurry composition for a metal film comprises abrasive particles, a solvent, an oxidant, a metal ion and a reducing agent , And the self-repair may be such that the metal ions are precipitated on the metal film by the reducing agent to form a plating layer.

Specifically, there is a limitation in preventing defects such as scratches from occurring during polishing of the metal film. Therefore, the polishing method of the present invention can minimize scratches and the like by performing simultaneous polishing and self-repairing of defects or dishing which have already occurred in polishing, and the process is simple .

The metal film polishing may use a CMP slurry composition for a metal film, and the CMP slurry composition for a metal film may include abrasive particles, a solvent, an oxidizing agent, a metal ion, and a reducing agent. Specifically, the slurry composition includes metal ions and a reducing agent, thereby performing self-repair by depositing metal ions on the metal film by plating using ions generated by the reducing agent. The metal ion may be the same metal as the metal to be polished, but is not limited thereto.

The self-repair may be electroless plating. Electroless plating is advantageous in that it is unnecessary to apply a voltage and the plating becomes uniform.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example

Specific specifications of the components used in the following examples and comparative examples are as follows.

(A) Oxidizing agent: hydrogen peroxide (H ₂ O ₂ ) of Dongwoo Fine-Chem Co., Ltd. was used.

(B) a metal ion

CuSO ₄ 5H ₂ O of Daejeong Co. was used to add (B-1) divalent copper ion (Cu ^{2 +} ).

(C) Reducing agent

(C-1) Ascorbic acid from Sigma-Aldrich Co., Ltd. was used.

(C-2) Glycolic acid from Sigma-Aldrich Co., Ltd. was used.

(D) Organic additives

(D-1) polyethylene glycol (PEG-3400 from Sigma-Aldrich) was used.

(D-2) bis (3-sulfopropyl) disulfide (SPS, Shanghai Jian Chao Chemical Technology Co. Ltd.) was used.

(E) Complexing agent

(E-1) glycine (manufactured by JE Chem. Co., Ltd.) was used.

(E-2) Ethylenediaminetetraacetic acid (EDTA, Sigma Aldrich) was used.

Example  1 to 4 and Comparative Example  1 to 5

In an amount shown in Table 1, components shown in Table 1, deionized water, abrasive particles (silica (SiO ₂₎ 0.1 wt.%), PH control agent (adjusted to pH 7), preservatives (1,2,3-triazol-3 mM To prepare a CMP slurry composition. Thereafter, the polishing evaluation was carried out by the following method, and the results are shown in Table 1. < tb >< TABLE >

<Polishing Condition>

- Polishing rate measurement wafer: 300mm Cu Blanket wafer

- Polishing equipment: Reflexion LK 300 mm (AMAT)

- Polishing pad: WVP6000 (NextPlanar)

- Polishing time: 30s

- Pressure: 2.2 psi

- Platen rpm: 98 rpm

- Head rpm: 87 rpm

- Flow rate: 250 ml / min

Property evaluation method

(1) Number of scratches (unit: pieces): Scratch counts were calculated by scanning the whole 300 mm wafer using a LS6800 manufactured by HITACHI Co., and the results are shown in Table 1 below.

(2) Dishing (unit: Å): After polishing with XE 300p from Park systems, the pattern profile was measured to calculate the dishing and is shown in Table 1 below.

Example Comparative Example One 2 3 4 One 2 3 4 5 (A) (% by weight) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 (B) (mM) (B-1) 30 30 30 30 - - - 30 - (C) (mM) (C-1) 20 20 - 20 - - - - 20 (C-2) - - 20 - - - - - - (D) (mM) (D-1) - One One One - One One One One (D-2) - 0.05 0.05 0.05 - 0.05 0.05 0.05 0.05 (E) (mM) (E-1) 16 16 16 - 16 16 - 16 16 (E-2) - - - 16 - - 16 - - Number of scratches 10 5 4 7 37 39 35 36 23 Dishing (Å) 1200 1120 1150 1140 1700 1720 1750 1630 1400

As shown in Table 1, the embodiment using the CMP slurry composition containing the metal ion and the reducing agent can reduce the number of scratches and the depth of dishing by self-repair of scratch and dishing, It can be seen that the comparative example using the CMP slurry composition that does not contain the high-scission and scratching agent has a high occurrence of scratch and dishing.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

Claims (15)

1. A CMP slurry composition for a metal film comprising abrasive particles, a solvent, an oxidizing agent, a metal ion, a reducing agent and an organic additive,
The metal ion is monovalent copper ion (Cu ^+), divalent copper ion (Cu ^2+), silver ions (Ag ^+), the family of cobalt ions (Co ^+), divalent cobalt ions (Co ^2+), refrain from cobalt ion (Co ³⁺ ), monovalent nickel ion (Ni ⁺ ), and bivalent nickel ion (Ni ²⁺ )
Wherein the reducing agent comprises at least one of ascorbic acid, glycolic acid, formaldehyde, hypophosphite, hydrazine, and dimethylamine borane,
The organic additive is selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), ethylene glycol-propylene glycol copolymer (PEG-PPG), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), cetyltrimethylammonium pro 3-N, N-dimethylaminodithiocarbamoyl-1-propanesulfonic acid (DPS), bis (3-sulfopropyl) disulfide (SPS), dodecyltrimethylammonium bromide , 3-mercapto-1-propanesulfonic acid (MPSA), and 2-mercapto-5-benzimidazolesulfonic acid (MBIS).
delete delete delete delete The CMP slurry composition for a metal film according to claim 1, wherein the composition further comprises at least one of a corrosion inhibitor, a pH adjuster and a complexing agent.
The CMP slurry composition for a metal film according to claim 1, wherein the composition comprises 1 mM to 300 mM of the metal ion.
The CMP slurry composition for a metal film according to claim 1, wherein the composition comprises 1 to 200 mM of the reducing agent.
The CMP slurry composition for a metal film according to claim 1, wherein the composition comprises 0.01 to 10% by weight of the oxidizing agent.
The CMP slurry composition for a metal film according to claim 1, wherein the composition has a molar ratio of the oxidizing agent to the reducing agent of 1: 1 to 10: 1.
The CMP slurry composition for a metal film according to claim 1, wherein the composition has a molar ratio of the reducing agent to the organic additive of 2: 1 to 50: 1.
2. The CMP slurry composition for a metal film according to claim 1, wherein the composition has a scratch number of 10 or less when the metal film is polished for 30 seconds at a pressure of 2.2 psi.
The CMP slurry composition for a metal film according to claim 1, wherein the composition has a dishing of 1200 ANGSTROM or less when polishing a metal film for 30 seconds at a pressure of 2.2 psi.
Polishing the metal film with a CMP slurry composition for a metal film and self-repairing the metal film,
Wherein the CMP slurry composition for a metal film comprises the CMP slurry composition for a metal film according to any one of claims 1 to 6,
Wherein the self-repairing step comprises depositing the metal ions on the metal film by the reducing agent to form a plating layer.
15. The polishing method according to claim 14, wherein the self-repair is electroless plating.