JP2001085374A - Abrasive liquid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having superior preventing effects of dishing or the like of a metal wiring layer by maintaining a polishing speed of the film on a surface to be polished, having an insulating layer and a metal layer and suppressing the etching rate, a method for polishing, and a method for manufacturing a semiconductor substrate. SOLUTION: This abrasive liquid composition polishes a surface to be polished having an insulating layer and a metal layer. The composition comprises a first abrasive liquid composition containing a compound having a structure, including a hydroxyl group in two or more adjacent carbon atoms in a molecule, a second abrasive liquid composition containing an organic acid and/or an oxidizer, and a third abrasive liquid composition containing an abrasive material further in the first or second composition. A method for polishing a semiconductor substrate comprises the steps of polishing a surface to be polished, having an insulating layer and a metal layer by using the first to the third compositions, and planarizing it. A method for manufacturing a semiconductor substrate comprises the steps of polishing a surface to be polished, having an insulating layer and a metal a layer by sing the first to the third composition, and planarizing it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing composition for polishing a surface to be polished having an insulating layer and a metal layer. More specifically, the present invention relates to a polishing composition, a polishing method, and a method for manufacturing a semiconductor substrate, which are applied to a technique for forming embedded metal wiring on a semiconductor substrate.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, a wiring-shaped groove is formed on the surface of an insulating film on a semiconductor substrate, and a metal film made of copper or the like is deposited on the insulating film having the groove. The polishing process of the method of forming a metal wiring layer by leaving a metal layer only in the groove by performing a polishing treatment with a polishing apparatus and a polishing liquid is a metal chemical mechanical polishing (Metal Chemical Mechanical Polishing).
ishing, hereinafter referred to as metal CMP).

However, in this metal CMP, a depression called “dishing” occurs in the metal wiring layer in the groove of the insulating film, and the cross-sectional area of the metal wiring layer is reduced.
There is a problem of causing an increase in electric resistance and the like. This dishing is said to occur when the surface of the metal wiring layer is polished or etched more excessively by the polishing composition than the surface of the insulating film. In particular, copper, which is one of the main wiring metals, has a defect that dishing is likely to occur due to excessive etching by the polishing composition.

Therefore, there is a demand for a polishing composition which does not cause dishing or other defects in the metal layer when forming wirings, while leaving an etching effect for polishing the metal film on the insulating film.

As a conventional polishing liquid, for example, Japanese Unexamined Patent Publication No.
JP-A-83780 and JP-A-11-21546 disclose a polishing solution containing benzotriazole or a derivative thereof as a protective film forming agent for a metal surface as a method for preventing dishing. Becomes strong, so that when the metal layer is polished in metal CMP, the polishing rate becomes insufficient. JP-A-11-116942 discloses a compound having 1 to 10 alcoholic hydroxyl groups or a compound having 1 to 10 alcoholic hydroxyl groups.
Although a polishing composition containing a nitrogen-containing basic compound having 10 is described, this polishing composition is intended to reduce particles attached to the wafer surface in mirror polishing of a semiconductor wafer, The problem to be solved is different.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to maintain a polishing rate of a metal film on a surface to be polished having an insulating layer and a metal layer, suppress an etching rate, and prevent dishing of a metal wiring layer. An object of the present invention is to provide a polishing composition, a polishing method, and a method for manufacturing a semiconductor substrate, which are excellent in effects.

[0007]

The gist of the present invention is [1].
A polishing composition for polishing a surface to be polished having an insulating layer and a metal layer, comprising a compound having a structure having a hydroxyl group at each of two or more adjacent carbon atoms in a molecule and water. (Hereinafter, also referred to as a first polishing composition), [2] a polishing composition according to [1] further containing an organic acid and / or an oxidizing agent (hereinafter, also referred to as a second polishing composition), [3] The polishing composition according to [1] or [2] (hereinafter also referred to as a third polishing composition) further containing an abrasive, [4] The polishing composition according to [1] to [3]. A polishing method for a semiconductor substrate, in which a polishing target surface having an insulating layer and a metal layer is polished and flattened using the composition, [5] the polishing liquid composition according to the above [1] to [3], Semiconductor substrate manufacturing method including a step of polishing and flattening a surface to be polished having an insulating layer and a metal layer About.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, 2
A compound having a structure having a hydroxyl group at each of at least two adjacent carbon atoms (hereinafter, also referred to as a hydroxyl group-containing compound)
There is one major feature in the use of, and by using a polishing composition containing such a hydroxyl group-containing compound, the polishing rate can be maintained, and excessive etching of the metal film can be prevented. An excellent effect that a polished surface without defects can be obtained is exhibited.

In the hydroxyl group-containing compound, from the viewpoint of maintaining the polishing rate and suppressing dishing, the number of adjacent carbon atoms having a hydroxyl group in the molecule is 2 or more, preferably 2 to 10, Two to seven are more preferred, and two to four are particularly preferred.

The structure of the hydroxyl-containing compound is as follows:
It is particularly preferred that a structure having a hydroxyl group at each of two or more adjacent carbon atoms is present at a terminal portion of the molecule.

As an example of this, the formula (I): R ¹ -X- (CH ₂ ) _q- [CH (OH)] _n -CH ₂ OH (I) (wherein R ¹ has 1 to 24 carbon atoms) The hydrocarbon group, X is (C
H ₂ ) _m , oxygen atom, sulfur atom, COO group, OCO group, N
R ² group, O (R ² O) P (O) O group, R ² is a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, m and q are 0 or 1,
n shows the integer of 1-4. )).

In the formula (I), the hydrocarbon group for R ¹ may be either aliphatic or aromatic, but is preferably aliphatic. The aliphatic structure may be either saturated or unsaturated, and may be a linear or branched group. However, from the viewpoint of suppressing dishing, a saturated structure is preferable. Chain structures are preferred. The hydrocarbon group preferably has 1 to 18 carbon atoms,
2-12 are more preferable. The carbon number is 1 or more from the viewpoint of suppressing dishing, and is 24 or less from the viewpoint of solubility of the compound represented by the formula (I) in water. m and q are preferably 1. The carbon number of the hydrocarbon of R ² is preferably 12 or less, more preferably 8 or less, and still more preferably 4 or less from the viewpoint of suppressing dishing. Particularly, R ² is preferably a hydrogen atom or a methyl group. n is preferably 2 or less, and more preferably 1 from the viewpoint of suppressing dishing.

The hydroxyl group-containing compound may have various functional groups other than the hydroxyl group in the molecule. However, from the viewpoint of maintaining a polishing rate and suppressing dishing, a carboxyl group, a sulfone group, a primary amino group, and the like. And those containing no phenolic hydroxyl group are preferred.

The molecular weight of the hydroxyl group-containing compound is determined from the viewpoint of maintaining the polishing rate and suppressing dishing.
It is preferably 5,000 or less, more preferably 1,000 or less, and particularly preferably 500 or less.

The hydroxyl group-containing compound maintains the polishing rate,
From the viewpoint of suppressing dishing, the value of the acid dissociation constant pKa in the aqueous solution is preferably 8 or more, more preferably 9 or more, and still more preferably 10 or more. However, in the case of a hydroxyl group-containing compound having two or more dissociable functional groups in the molecule, the pKa here is the value of the first dissociation constant. In addition, the solubility of the hydroxyl group-containing compound is preferably 0.5% by weight or more in water at 25 ° C. at the pH used as the polishing composition, from the viewpoint of being incorporated into an aqueous medium, More preferably, the dissolution is 1.0% by weight or more.

Specific examples of these hydroxyl group-containing compounds include 1,2-butanediol, 1,2-heptanediol, 1,2-hexanediol (a in Table 1 described later),
Alkanediols such as 1,2-octanediol,
Alkantriols such as 1,2,3-hexanetriol, 1,2,6-hexanetriol, 1,2,3-heptanetriol, butyl glyceryl ether (b in Table 1 described later), pentyl glyceryl ether; Glyceryl ethers such as xyl glyceryl ether, octyl glyceryl ether, butanoic acid monoglyceride,
Monoglycerides such as pentanoic acid monoglyceride, hexanoic acid monoglyceride, heptanoic acid monoglyceride (c in Table 1 below), octanoic acid monoglyceride and the like; Partial esters of polyhydric alcohols, compounds obtained by reacting glycidol with monoalkylamines such as hexylamine or dialkylamines such as dipropylamine (d in Table 1 described below), diethyl tartrate, dibutyl tartrate, dipropyl tartrate (described later) E) in Table 1 above, diesters of tartaric acid such as dihexyl tartrate, and 1,2-cyclohexanediol. Of these, alkanediols and glyceryl ethers are preferred from the viewpoints of polishing rate and suppression of dishing. These hydroxyl group-containing compounds may be used alone or in combination of two or more.

The amount of the hydroxyl group-containing compound in the polishing composition is preferably 0.01 to 30% by weight from the viewpoint of maintaining the polishing rate and suppressing dishing.
0.05 to 5% by weight is more preferable, and 0.1 to 3% by weight.
Is more preferred.

The water used in the present invention is used as a medium. The compounding amount is preferably 60 to 99.99% by weight, more preferably 70 to 9% by weight in the polishing composition from the viewpoint of efficiently polishing the object to be polished.
9.4% by weight, more preferably 80 to 99.0% by weight
It is.

The pH of the first polishing composition of the present invention having such a composition is preferably 2 to 11 from the viewpoints of keeping the polishing rate at a practical level, suppressing dishing and removing fine scratches on the surface. Preferably, 2-7 are more preferable, 2-6 are more preferable, and 3-5 are particularly preferable. In order to adjust the pH within the above range, if necessary, nitric acid, inorganic acids such as sulfuric acid, organic acids, potassium hydroxide,
Basic substances such as sodium hydroxide, ammonia, and organic amines can be appropriately blended.

The second polishing composition of the present invention is obtained by further adding an organic acid and / or an oxidizing agent to the first polishing composition. In the present invention, by using such an organic acid, a complex is formed or bonded with various metals constituting the metal layer, particularly copper, and the metal layer is made to be a fragile layer. The effect of facilitating this is exhibited.

In particular, by using a combination of an organic acid and a compound having a structure having a hydroxyl group at two or more adjacent carbon atoms in the molecule, the polishing rate can be maintained and dishing can be prevented. .

An organic acid is an organic compound exhibiting acidity.
Examples of these acidic organic compounds include a carboxyl group, a phosphon group, a phosphine group, a sulfone group, a sulfine group, a phenol group, an enol group, a thiophenol group,
Those having a functional group such as an imide group, an oxime group, an aromatic sulfamide group, and a primary and secondary nitro group are exemplified.

The molecular weight of the organic acid used in the present invention is 1
000 or less is preferable, and 500 or less is more preferable.

The organic acid having a carboxyl group includes
From the viewpoint of solubility in water, a monocarboxylic acid having 1 to 24 carbon atoms, a dicarboxylic acid, a hydroxycarboxylic acid and an aminocarboxylic acid are preferable, and the number of carbon atoms is more preferably 1 to 18, and still more preferably 1 to 12. And particularly preferably 1 to 8. Specifically, as the monocarboxylic acid,
Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, pyruvic acid and the like; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid and phthalic acid; Acids, tartaric acid, glycolic acid, lactic acid, citric acid, malic acid, etc .; Examples of aminocarboxylic acids include ethylenediaminetetraacetic acid, nitrilotriacetic acid and the like. Examples of the organic acid having a phosphon group include aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), hexamethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylene Examples of organic acids having a phosphine group such as phosphonic acid) include ethyl phosphite, and examples of organic acids having a sulfone group include methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. Examples of the organic acid having the formula include benzenesulfinic acid and p-toluenesulfinic acid. Among these, organic acids having a carboxyl group are preferred, and more specifically, monocarboxylic acids, dicarboxylic acids, hydroxycarboxylic acids, and aminocarboxylic acids are preferred, and acetic acid, oxalic acid, succinic acid, glycolic acid, lactic acid, and citric acid are preferred. Acids, malic acid, tartaric acid, gluconic acid, ethylenediaminetetraacetic acid and nitrilotriacetic acid are more preferred, and glycolic acid and gluconic acid are even more preferred. These organic acids may be used alone or in combination of two or more.

The organic acid is used in the second polishing composition with water as a medium. The compounding amount of the organic acid in the second polishing composition can be variously selected in order to secure a polishing rate at a practical level for removing the metal layer and to prevent excessive etching of the metal layer. , Preferably 0.1 to 10% by weight, more preferably 0.2 to 10% by weight.
It is 8% by weight, more preferably 0.3 to 5% by weight.

Among the organic acids, metals, especially copper, are dissolved and etched in the presence of an aqueous medium, and the etching rate a obtained by the following etching test A is 3Ａ / mi.
Compounds of n or more can be used as an etching agent. That is, the etching test A is firstly 100 m in length.
m copper ribbon (manufactured by Nilaco Co., Ltd .: thickness 0.10 mm, width 6 mm), and after dirt on the surface is wiped off with paper,
Ultrasonic cleaning is performed for 1 minute in a state of being immersed in normal hexane, sufficiently degreased, and dried. Thereafter, the metal test piece is spirally wound so that the polishing liquid is immersed in the whole surface of the ribbon, and the metal test piece before the test is used. The weight before immersion is measured by a precision balance.

Next, 100 g of an etching solution prepared as a 2% by weight aqueous solution of an etching agent and adjusted to pH 8 ± 0.5 with aqueous ammonia was prepared in a 150 cc beaker (Teraoka 150 cc Descup).
The metal test piece is immersed therein at 25 ° C. for 12 hours.
During the immersion, the copper ribbon is stirred by a magnetic stirrer to such an extent that the copper ribbon is rotated by the flow of the etching solution. After the test, the surface of the copper ribbon is sufficiently wiped off, the weight is measured again with a precision balance, and the weight is taken as the weight after the test. The amount of decrease in the thickness of the copper is converted from the decrease in the weight of the copper ribbon before and after the test, and is divided by the etching time to obtain the etching rate a. From the viewpoint of obtaining a practical polishing rate, the etching rate a obtained from the etching test A is 3 ° / m.
An etching agent of in or more is preferable, an etching agent of 5 ° / min or more is more preferable, and an etching agent of 10 ° / min or more is further preferable. The etching rate a in this case may be an etching rate when two or more etching agents are used in combination.

The etching agent dissolves and etches a metal, particularly copper, in the presence of an aqueous medium, and the etching rate a obtained by the etching test A is 3 ° / mi.
More than n inorganic acids can also be used.

Preferred etching agents include one or more compounds selected from the following groups A to E from the viewpoint of having an appropriate etching rate. A: an aliphatic organic acid having 6 to 6 carbon atoms and having 1 to 3 carboxyl groups B: an aromatic organic acid having 7 to 10 carbon atoms and having 1 to 4 carboxyl groups C: 1 to 6 carbon atoms or less Organic acid having four phosphonic acid groups D: Formula (II) in the molecule:

[0030]

Embedded image

Polyaminocarboxylic acid having two or more structures represented by the following formula: E: inorganic acid

Specifically, as an aliphatic organic acid having a carbon number of 6 or less and A having 1 to 3 carboxyl groups, formic acid,
Monocarboxylic acids such as acetic acid and propionic acid; polycarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid and tricarballylic acid; glycolic acid, lactic acid,
-Hydroxycarboxylic acids such as hydroxypropionic acid, malic acid, tartaric acid, citric acid, gluconic acid; glycine;
Examples include amino acids such as alanine and aspartic acid. Examples of the aromatic organic acid having 1 to 4 carboxyl groups having 7 to 10 carbon atoms of B include benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid, mandelic acid, and salicylic acid. Examples of the organic acid having 1 to 4 phosphonic acid groups having 6 or less carbon atoms of C include phosphonic acids such as methylphosphonic acid and phenylphosphonic acid; methylphosphinic acid;
Phosphinic acids such as phenylphosphinic acid; phosphonic esters such as methyl phosphonate; aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1-
And aminophosphonic acids such as diphosphonic acid. D
As a polyaminocarboxylic acid having two or more structures represented by the formula (II) in the molecule of, ethylenediaminetetraacetic acid,
Examples include nitrilotriacetic acid, diethylenediaminepentaacetic acid, triethylenetetraminehexaacetic acid, and hydroxyethylethylenediaminetriacetic acid. Hydrochloric acid as an inorganic acid of E,
Examples include perchloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, and phosphinic acid. Among these, from the viewpoint of the polishing rate, a polycarboxylic acid or hydroxycarboxylic acid belonging to A or B, an aminophosphonic acid belonging to C, and two or more structures represented by the formula (II) in a molecule belonging to D are included. Polyaminocarboxylic acid, hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid belonging to E are preferred, and oxalic acid, succinic acid, glycolic acid, lactic acid, citric acid, malic acid, gluconic acid, phthalic acid, aminotri (methylenephosphonic acid), 1- Hydroxyethylidene-1-diphosphonic acid, ethylenediaminetetraacetic acid, hydrochloric acid and sulfuric acid are more preferred. These etchants may be used alone or in combination of two or more.

The etching rate a of these etching agents is, for example, glycolic acid: 60 ° / min, citric acid: 25 ° / min, phthalic acid: 50 ° / min, aminotri (methylenephosphonic acid): 10 ° / min, ethylenediamine Acetic acid: 30Å / min, acetic acid: 70Å
/ Min, glycine: 40Å / min, hydrochloric acid: 400Å
/ Min, sulfuric acid: 100 ° / min.

When the etching agent used in the present invention is prepared into a polishing composition (composition not containing the above-mentioned hydroxyl group-containing compound) further comprising an oxidizing agent and abrasive grains, the following etching test B It is preferable to adjust the type, content, etc. of the resulting polishing composition so that the etching rate b of the polishing composition is 20 ° / min or more. That is, in the etching test B, a polishing liquid composition containing water, an abrasive, an etching agent, and, if necessary, an oxidizing agent is used as an etching liquid in the etching test A, and the substrate is immersed at room temperature (25 ° C.) for 2 hours to adjust the pH. Except for adjusting to 4.0 ± 0.5, the same operation as in the etching test A is performed. The etching rate obtained by the etching test B is defined as an etching rate b. From the viewpoint of obtaining a practical polishing rate, the etching rate b obtained from the etching test B is 20 °.
/ Min or more, more preferably 30 ° / min or more, and even more preferably 50 ° / min or more. The etching rate b in this case may be the etching rate of the polishing composition using two or more etching agents in combination.

In the present invention, by using such an etching agent, a complex is formed or bonded with various metals constituting the metal layer, particularly copper, and is easily removed from the surface as a water-soluble salt and / or chelate compound. In polishing, the effect of improving the polishing rate of the metal layer is exhibited.

The amount of the etching agent in the second polishing composition can be selected variously in order to secure a polishing rate at a practical level for removing the metal layer and to prevent excessive etching of the metal layer. And preferably 0.1 to 10
%, More preferably 0.2 to 8% by weight, even more preferably 0.3 to 5% by weight.

The oxidizing agent used in the present invention oxidizes a metal. In the present invention, it is considered that the effect of oxidizing the metal layer and promoting the mechanical polishing effect of the metal layer is exhibited by using such an oxidizing agent.

As the oxidizing agent, peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, nitric acid or a salt thereof, peroxoic acid or a salt thereof, oxyacid or a salt thereof, metal salts,
And sulfuric acids.

Specific examples of the peroxide include hydrogen peroxide, sodium peroxide, barium peroxide and the like; permanganic acid and salts thereof include potassium permanganate; and chromic acid and salts thereof include: Metal chromate salts, metal dichromate salts, etc .; as nitrates, iron (III) nitrate, ammonium nitrate, etc .;
Peroxodisulfuric acid, ammonium peroxodisulfate, metal peroxodisulfate, peroxophosphoric acid, peroxosulfuric acid, sodium peroxoborate, performic acid, peracetic acid,
Perbenzoic acid, perphthalic acid, etc .; oxygen acids or salts thereof include hypochlorous acid, hypobromous acid, hypoiodic acid, chloric acid,
Bromic acid, iodic acid, perchloric acid, sodium hypochlorite,
Calcium hypochlorite, etc .; metal salts include iron chloride
(III), iron (III) sulfate, iron (III) citrate, iron (III) ammonium sulfate and the like. Preferred oxidizing agents include hydrogen peroxide, iron (III) nitrate, peracetic acid, ammonium peroxodisulfate, iron (III) sulfate and iron (III) ammonium sulfate, with hydrogen peroxide being particularly preferred. These oxides may be used alone or in combination of two or more.

The oxidizing agent is used in the second polishing composition with water as a medium. The amount of the oxidizing agent in the second polishing composition is preferably 0.1 to 60% by weight, and more preferably 0.2 to 60% by weight, from the viewpoint of obtaining a practical level of polishing rate by rapid oxidation of the metal layer. To 50% by weight, more preferably 0.3 to 30% by weight. The amount of the hydroxyl group-containing compound in the second polishing composition is preferably 0.01 to 30% by weight, more preferably 0.05 to 5% by weight, and still more preferably 0.1 to 3% by weight. . The amount of water is preferably 40 to 99.8.
It is 9% by weight, more preferably 70 to 99.4% by weight, even more preferably 80 to 99% by weight. It is preferable that the pH of the second polishing composition having such a composition is appropriately adjusted similarly to the first polishing composition.

The first and second polishing compositions of the present invention are effective in a polishing system using a fixed whetstone, a polishing pad having abrasive grains fixed in the pad, and the like. For example, by using the first and second polishing liquid compositions of the present invention during polishing by a polishing method using a fixed grindstone, the polishing rate can be maintained and dishing of the metal layer can be suppressed.

The third polishing composition of the present invention is obtained by further adding an abrasive to the first or second polishing composition, and is used in a polishing method using a free abrasive.

As the abrasive, an abrasive generally used for polishing can be used, for example, metal, metal or metalloid carbide, metal or metalloid nitride, metal or metalloid oxide. , Metal or metalloid borides, diamonds and the like. Examples of the metal or metalloid element include those belonging to Groups 3A, 4A, 5A, 3B, 4B, 5B, 6B, 7B or 8B of the periodic table. Examples include silicon dioxide, aluminum oxide, cerium oxide, titanium oxide, zirconium oxide, silicon nitride, manganese dioxide, silicon carbide, zinc oxide, diamond and magnesium oxide. Among them, silicon dioxide, aluminum oxide, and cerium oxide are preferred. Specific examples of the silicon dioxide include colloidal silica particles, fumed silica particles, and surface-modified silica particles; and aluminum oxide includes α-alumina. particle,
γ-alumina particles, δ-alumina particles, θ-alumina particles, η-alumina particles, amorphous alumina particles, fumed alumina, colloidal alumina, etc. with different production methods; cerium oxide has an oxidation number of 3 or Tetravalent ones and those having a hexagonal, equiaxed, or face-centered cubic crystal system are exemplified. These abrasives may be used alone or in combination of two or more.

The average particle size of the primary particles of such an abrasive is preferably 5 to 1000 nm, more preferably 10 to 500 nm.
nm, more preferably 20 to 300 nm, particularly preferably 50 to 200 nm, most preferably 50 to 100 nm. The lower limit of the average particle size is preferably 5 nm or more from the viewpoint of maintaining a constant polishing rate, and the upper limit is preferably 1000 nm or less from the viewpoint of not generating scratches on the surface of the object to be polished. .

In particular, when silicon dioxide is used as the abrasive, the average particle size of the primary particles is 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, from the viewpoint of improving the polishing rate.

The average particle size of the primary particles of the abrasive is
0.1% polystyrene sodium sulfonate aqueous solution 100
0.1 g of the abrasive is added to g, then ultrasonic waves are applied, and the dispersion of the abrasive is observed with a transmission electron microscope, and determined by image analysis.

In the case where the third polishing composition is used for forming wiring of a semiconductor device, the polishing material which is particularly preferably used has a purity of preferably 98% by weight from the viewpoint of improving the synergistic effect of addition with the hydroxyl group-containing compound. %, More preferably 99% by weight or more, particularly preferably 99.9% by weight or more. As such an abrasive, fumed silica produced by high-temperature hydrolysis of a volatile silicon compound such as silicon tetrachloride in an oxyhydrogen flame, or a production method using an alkali silicate or ethyl silicate as a starting material can be obtained. Colloidal silica is mentioned.

The purity of the abrasive is determined as follows. That is, it can be measured by dissolving 1 to 3 g of an abrasive in an aqueous acid or alkali solution and quantifying silicon ions by ICP (plasma emission analysis).

Such an abrasive is used in a so-called slurry state using water as a medium in the third polishing composition. The amount of the abrasive in the third polishing composition can be variously selected depending on the viscosity of the polishing composition of the present invention, the required quality of the object to be polished, and the like. Preferably, it is 0.02 to 20% by weight, more preferably 0.02% by weight.
More preferably, the amount is from 0.05 to 10% by weight.

The amount of the hydroxyl group-containing compound in the third polishing composition is preferably 0.01 to 30% by weight, and more preferably 0.05 to 5% by weight, from the viewpoint of maintaining the polishing rate and suppressing dishing. Is more preferable, and 0.1 to 3% by weight is further preferable.

The amount of the organic acid in the third polishing composition can be selected variously in order to secure a practical level of polishing rate for removing the metal layer and to prevent excessive etching of the metal layer. For example, it is preferably 0.1 to 10% by weight, more preferably 0.2 to 8% by weight, and still more preferably 0.3 to 5% by weight.

The amount of the oxidizing agent in the third polishing composition is preferably 0.1 to 60% by weight, more preferably 0 to 60% by weight, from the viewpoint of obtaining a practical level of polishing rate by rapid oxidation of the metal layer. 0.2 to 50% by weight, more preferably 0.3 to 30% by weight.

The amount of water in the third polishing composition is preferably 40 to 99.88% by weight, more preferably 60 to 99.4% by weight, and further preferably 75 to 9% by weight.
9% by weight. It is preferable that the pH of the third polishing composition having such a composition is appropriately adjusted similarly to the first polishing composition.

The polishing composition of the present invention is used for metal CMP for polishing a surface having an insulating layer and a metal layer. As a metal forming the metal layer, copper or copper alloy,
Aluminum or an aluminum alloy, tungsten, or the like can be given. Among these, copper or a copper alloy is preferable particularly when used in the step of forming a buried metal wiring on a semiconductor substrate. When the polishing composition of the present invention is used to form such a copper or copper alloy metal wiring layer, the effects of maintaining the polishing rate and suppressing dishing of the buried metal wiring layer are particularly remarkably exhibited. As the material for forming the insulating layer, any of organic and inorganic materials may be used, such as silicon dioxide, fluorine-added silicon dioxide, hydrogen-containing SOG (spin-on-glass), and nitride (for example, tantalum nitride, titanium nitride, etc.). ), Inorganic SOG, polyimide,
Organic materials such as fluorinated polyimide, aromatic polyether, and fluorocarbon are exemplified.

The shape of the object to be polished is preferably such that a wiring-shaped groove is formed on the surface of the insulating film on the semiconductor substrate, and a metal is deposited on the insulating film including the groove. Further, a barrier film made of tantalum, titanium, or a nitride thereof may be provided between the insulating film and the metal layer. In particular, when the metal layer is copper or a copper alloy, it is preferable to provide the barrier film because diffusion of copper to the insulating layer can be prevented.

The method for polishing a surface to be polished having an insulating layer and a metal layer according to the present invention includes a step of polishing and flattening a semiconductor substrate using the polishing composition of the present invention.

Further, the method for manufacturing a semiconductor substrate according to the present invention comprises:
Polishing a semiconductor surface having an insulating layer and a metal layer using the polishing composition of the present invention can maintain the polishing rate of the metal layer and suppress dishing of the buried metal wiring layer. Can be suitably used.

[0058]

EXAMPLES Examples 1 to 14 and Comparative Examples 1 to 4 Table 1 shows compounds used in Examples 1 to 14 each having a structure having a hydroxyl group at two or more adjacent carbon atoms in the molecule (a hydroxyl group-containing compound). )showed that. The hydroxyl group-containing compound shown in Table 1 was mixed with the organic acid and hydrogen peroxide shown in Table 2 so as to have the compositions shown in Table 2, respectively.
After mixing and stirring 5% by weight of the abrasive shown in the above and the remaining water, the pH of the mixture was adjusted to 4.0 to obtain a polishing composition. In addition, each abrasive used was fumed silica (1
Secondary particle size: 50 nm), colloidal silica (primary particle size: 3)
0 nm). In addition, all of the hydroxyl group-containing compounds a to e in Table 1 dissolve in water in an amount of 1.0% by weight or more.
The object to be polished was polished by a single-side polishing machine under the following conditions.

<Setting conditions for single-side processing machine> Single-side processing machine used: Single-side processing machine manufactured by Engis Co., Ltd. (platen size: 30 cm) Processing pressure: 29.4 × 10 ³ Pa Polishing pad: Upper layer: “IC1000” (Rodel Nitta) Lower layer: "SUBA400" (manufactured by Rodel Nitta) Surface plate rotation speed: 60 rpm Work rotation speed: 50 rpm (surface plate and work rotate in the same direction) Polishing liquid composition supply flow rate: 100 ml / min Polishing time: 10 minutes

The properties of the polishing composition such as relative polishing rate, relative etching rate, dishing of the surface to be polished and the like were evaluated according to the following methods.

(Relative Polishing Speed) The object to be polished used for obtaining the relative polishing speed is a rolled copper plate having a thickness of 1 mm. The polishing rate was determined by measuring a change in thickness before and after polishing and dividing the result by the polishing time to obtain a relative value based on Comparative Example 1, 2, or 3. Table 2 shows the results. The thickness of the copper plate was measured using a high-precision digital length measuring device “MINIAX” manufactured by Tokyo Seimitsu Co., Ltd.

(Relative etching rate) The relative etching rate is determined by determining the etching rate of the polishing composition containing the hydroxyl group-containing compound by the type and amount of the abrasive, the oxidizing agent, and the etching agent, not containing the hydroxyl group-containing compound. Is the value obtained by dividing by the etching rate b of the polishing liquid composition with the same value. Examples 1 to 5 and 9 to 10 are Comparative Example 1 and Example 6
8 are based on Comparative Example 2, and Examples 13 and 14 are based on Comparative Example 3. Note that, different from the above-mentioned rules, the relative etching rate was calculated based on Comparative Example 1 in Example 11, Comparative Example 2 in Example 12, and Comparative Example 1 in Comparative Example 4. The etching rates of the polishing compositions of Examples 1 to 14 and Comparative Example 4 were measured under the same conditions as in the above-mentioned etching test B except that these polishing compositions were used.

(Dishing) For evaluation of dishing, a wafer with a copper damascene wiring pattern (manufactured by SKW,
"SKW6-2", size: 200mm) Cut out 20mm square wafer chip, fix 5 wafer chips on ceramic bonding board, and confirm the condition under the above conditions, around the copper wiring area of 150μm wiring width Was polished until the copper film was removed and the barrier film appeared, and further polished for 20% of the polishing time required up to this point to obtain a dishing evaluation sample. The dishing was evaluated by measuring a cross-sectional profile of a copper wiring portion having a wiring width of 150 μm on a wafer chip using a surface roughness measuring device (“SV-600” manufactured by Mitutoyo Corporation). In addition, when there is no dent of 0.15 μm or more in the measured cross-sectional shape profile of the copper wiring, dishing is not performed. When there is a dent of 0.15 μm or more, dishing is performed. Indicated by

The etching rate b of the polishing composition used in Comparative Examples 1 to 3 is as follows. Comparative Example 1 (80 ° / min), Comparative Example 2 (80 ° / mi)
n), Comparative Example 3 (200 ° / min)

[0065]

[Table 1]

[0066]

[Table 2]

From the results of Tables 1 and 2, all of the polishing compositions of Examples 1 to 14 in which the hydroxyl group-containing compound was blended into the polishing composition were compared with the polishing compositions of Comparative Examples 1 to 3 not blended. It can be seen that the etching rate was suppressed without substantially lowering the polishing rate, and no dishing occurred.

Further, it can be seen that the polishing rates of the polishing compositions of Examples 1 to 5 are remarkably higher than those of the polishing composition of Comparative Example 4 using benzotriazole instead of the hydroxyl group-containing compound.

Further, by using a hydroxyl group-containing compound, an organic acid and an oxidizing agent together, a higher polishing rate can be realized.
It can be seen that dishing can be prevented.

[0070]

By using the polishing composition of the present invention for polishing a surface to be polished having an insulating layer and a metal layer, the polishing rate of the metal film is maintained, the etching rate is suppressed, and the wiring metal layer is dished. And the like are not generated.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/306 H01L 21/306 M (72) Inventor Toshiya Hagiwara 1334 Minato, Wakayama-shi Kao Corporation Laboratory F term (reference) 3C058 AA07 BC02 CA01 CB01 CB03 DA02 DA12 5F043 AA26 BB18 BB30 DD16 EE08 FF07 GG10

Claims (6)

[Claims] 1. A polishing composition for polishing a surface to be polished having an insulating layer and a metal layer, comprising a compound having a structure having a hydroxyl group at two or more adjacent carbon atoms in a molecule and water. Polishing liquid composition. 2. The polishing composition according to claim 1, wherein the compound having a structure having a hydroxyl group at two or more adjacent carbon atoms in the molecule is a compound represented by the following formula (I). R ¹ -X- (CH ₂ ) _q- [CH (OH)] _n -CH ₂ OH (I) (wherein, R ¹ is a hydrocarbon group having 1 to 24 carbon atoms, and X is (C
H ₂ ) _m , oxygen atom, sulfur atom, COO group, OCO group, N
R ² group, O (R ² O) P (O) O group, R ² is a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, m and q are 0 or 1,
n shows the integer of 1-4. ) 3. The polishing composition according to claim 1, further comprising an organic acid and / or an oxidizing agent. 4. The method according to claim 1, further comprising an abrasive.
The polishing composition according to any one of the above. 5. A method for polishing a semiconductor substrate, comprising polishing a surface to be polished having an insulating layer and a metal layer by using the polishing composition according to claim 1. 6. A method for manufacturing a semiconductor substrate, comprising the step of polishing and flattening a surface to be polished having an insulating layer and a metal layer using the polishing composition according to claim 1.