JP2002050607A - Substrate treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate treatment method which can prevent metal impurity ions from attaching, without corroding metallic wirings, etc., in a substrate surface, and can improve the cleanliness level of a substrate by surely removing particle and metal impurities which attach to a recess and a step part generated in a metal wiring. SOLUTION: A substrate 1 is treated in a first process A for cleaning with organic alkaline treatment liquid, a second process B for cleaning after the first process by means of organic acid treatment liquid and a third process C for cleaning, after the second process by means of ultrasound cleaning fluid oscillated by ultrasonic wave. An organic alkaline treatment liquid and organic acid treatment liquid are non-reactive to a metallic material of a metal wiring of the substrate 1 and can improve the cleanliness level of the substrate 1, by preventing metal impurity ions from attaching, without corroding the metal wrings, etc., of a substrate surface; since it contains complexing agent which forms a complex with particles in a metallic material and metals included in polishing solution, when the substrate 1 is chemomechanically polished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a substrate processing method.

[0002]

2. Description of the Related Art In recent years, as electronic devices have been downsized, the number of wiring layers has been increased with the increase in the density of semiconductor devices, and the formation of metal wiring on a semiconductor substrate and the flattening of the interlayer insulating film of the multilayer wiring have been advanced. Chemical mechanical polishing (hereinafter, referred to as CMP) has been used as a technique for forming the surface.

In CMP, a semiconductor wafer as a substrate is pressed against a cloth called a buff while supplying a mixture of a polishing agent and a chemical (hereinafter, also referred to as a polishing liquid) called a slurry. Alternatively, this is a technique in which an interlayer insulating film or a metal material on a semiconductor wafer is polished by rotating a buff to flatten the film.

[0004] Particles such as used abrasives (alumina particles and silica particles), metal impurities contained in chemicals, and metal wiring on the semiconductor wafer are formed on the surface of the semiconductor wafer as a substrate after being processed by CMP. Large amount of metal ions and fine particles used in the process are attached. For example, metal ions such as copper diffuse into a semiconductor wafer, lowering insulation resistance and adversely affecting semiconductor devices. Therefore, the surface of the semiconductor wafer is cleaned with high cleanliness, and ions and fine particles of particles and metal impurities. Must be completely removed.

[0005]

Conventionally, as a method of cleaning a substrate after being processed by CMP, a so-called RC is used.
A washing is being performed. The RCA cleaning includes a first step of removing particles with an alkaline solution (ammonia-hydrogen peroxide solution), and a treatment of the substrate treated in the first step with an acid solution (DHF (dilute hydrofluoric acid) or the like). And a second step of removing metal impurities.

However, the ammonia used in the first step of the RCA cleaning easily etches the metal,
It has a property that ions of metal impurities contained in the solution easily adhere to the substrate surface in reverse. For example, when copper wiring is exposed as metal wiring on the substrate surface, copper forms a complex with ammonia and elutes, and fine pits are generated on the copper metal wiring film, thereby lowering the planar accuracy of the surface. May be. Also, if metal impurity ions adhere to these pits,
Even if washing is performed with an acid solution in the second step, it is difficult to sufficiently remove it.

[0007] DHF (dilute hydrofluoric acid) used in the second step has a strong dissolving power for metals, and the metal wiring film exposed on the substrate surface is easily etched.

As shown in FIG. 8, when metal wirings and the like are formed on a semiconductor wafer as a substrate by CMP,
So-called dishing occurs. What is dishing?
FIG. 8 is a cross-sectional view schematically showing a state in which dishing has occurred on a semiconductor wafer as a substrate.

Metal wiring exposed on the surface of a semiconductor wafer as a substrate is formed by forming an interlayer insulating film 53 made of a silicon oxide (SiO ₂ ) film or the like on a semiconductor wafer 1 made of a silicon (Si) substrate or the like. A metal wiring 51 such as copper (Cu) is buried in a predetermined portion of the film 53 via a barrier film 52 made of titanium (Ti), titanium nitride (TiN) or the like. In this step, unnecessary portions of the metal wiring 51 and the barrier film 52 are polished and removed by CMP, but the metal wiring 51 (for example, copper (C
u)) is softer than the barrier film 52 and has a higher polishing rate. Therefore, the central portion of the surface of the metal wiring 51 is excessively polished, a dent is generated, and a dishing 55 is formed.

When the dishing 55 is formed, a step 56 is formed at the boundary between the metal wiring 51 and the barrier film 52.
Are generated, particles and metal impurities are adsorbed in the step portion 56 and the dishing 55, and a sufficient cleaning effect may not be obtained even when cleaning is performed in the first step and the second step. Note that the barrier film 52 is formed of the metal wiring 5.
This is to prevent the ions of the metal used in 1 from diffusing into the semiconductor wafer 54.

The present invention has been made in view of the above points, and does not corrode a metal wiring or the like formed in a state where a metal material is exposed on a substrate surface, and does not allow metal impurity ions to adhere to the substrate surface. It is an object of the present invention to provide a substrate processing method capable of preventing adhesion, and reliably removing particles and metal impurities adhering to dents and steps formed in metal wiring and improving the cleanliness of the substrate.

[0012]

The substrate processing method of the present invention performs a chemical mechanical polishing process by supplying a polishing liquid to a substrate having a metal wiring with a metal material exposed on the surface.
A substrate processing method for processing the substrate after the chemical mechanical polishing treatment, wherein an organic alkali that is non-reactive with the metal material, a complex with a metal contained in the metal material particles and the polishing liquid. A first step of washing the substrate with an organic alkaline treatment liquid containing a complexing agent that forms a metal material, an organic acid that is non-reactive with the metal material after the first step, Cleaning the substrate with an organic acid treatment liquid containing particles of the above and a complexing agent that forms a complex with a metal contained in the polishing liquid.

Further, after the second step, a third step of cleaning the substrate with an ultrasonic cleaning fluid excited by ultrasonic waves.
It has a process of.

Further, the ultrasonic cleaning fluid is pure water.

Further, the third step includes a step of drying the substrate by rotating at a high speed after cleaning the substrate with an ultrasonic cleaning fluid.

Further, the metal material is copper, tungsten or aluminum.

The organic alkali is a quaternary ammonium salt and / or an organic amine.

The quaternary ammonium salt is a group consisting of tetramethylammonium hydroxide (TMAH), trimethyl-2-hydroxyethylammonium hydroxide (TMAH), and trimethyl-2-hydroxyethylammonium hydroxide (choline). At least one compound selected from the group consisting of:

The organic amine is at least one compound selected from the group consisting of trimethylamine, triethanolamine, ethylenediamine, guanidine and toluidine.

The complexing agent contained in the organic alkaline treating solution is a fluoride ion, an OH group and / or an O ^- group having a cyclic skeleton in the molecular structure and bonded to a carbon atom constituting the ring. At least one substance selected from the group consisting of compounds having at least one.

Further, the organic alkaline processing solution contains a second complexing agent having a metal ligand, and the second complexing agent is a compound having a donor atom, sulfur or carbon, or a donor atom. At least one compound selected from the group consisting of a compound having a certain nitrogen, a compound having a carboxyl group as a metal coordinating group, and a compound having a carbonyl group as a metal coordinating group.

Further, the organic acid is a carboxylic acid which forms a complex with the oxide particles of the metal material, and the carboxylic acid is oxalic acid, citric acid, malic acid, maleic acid, succinic acid, tartaric acid, It is at least one compound selected from the group consisting of malonic acid and salts thereof.

The complexing agent contained in the organic acid treatment solution is a polyaminocarboxylic acid and / or ammonium fluoride.

The polyaminocarboxylic acids are ethylenediaminetetraacetic acid (EDTA), trans-1,2
-Cyclohexanediaminetetraacetic acid (CyDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), N- (2-hydroxyethyl) ethylenediamine-N, N ', N'-triacetic acid (EDTA-
OH) and at least one compound selected from the group consisting of salts thereof.

Further, according to the substrate processing method of the present invention, a polishing liquid is supplied to a substrate having a metal wiring in a state where a metal material is exposed on the surface to perform a chemical mechanical polishing process, and the chemical mechanical polishing process is performed. A substrate processing method for processing the substrate after, an organic acid non-reactive with the metal material, a complexing agent that forms a complex with the metal material particles and the metal contained in the polishing liquid, A first step of cleaning the substrate with an organic acid treatment liquid containing: and after the first step, an organic alkali non-reactive with the metal material, particles of the metal material and the polishing liquid. And a second step of washing the substrate with an organic alkaline treatment solution containing a metal and a complexing agent that forms a complex.

[0026]

Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a flowchart showing steps of a substrate processing method according to the present invention.
FIG. 3 is a view showing processing steps of the substrate processing method according to the present invention, FIG. 3 is a perspective view showing a substrate cleaning apparatus used in the substrate processing method according to the present invention, and FIG. It is sectional drawing which looked at the sonic cleaning apparatus from the front.

As shown in FIGS. 1 and 2, the substrate processing method according to the present invention comprises a first step A in which a substrate 1 is treated with an organic alkaline processing liquid, and a substrate treated in the first step A. The method includes a second step B in which the substrate 1 is treated with an organic acidic treatment liquid, and a third step C in which the substrate 1 treated in the second step B is subjected to ultrasonic cleaning and drying. As the substrate 1, various substrates such as a semiconductor wafer and a glass substrate can be applied. However, in the substrate processing method according to the present invention, a metal wiring or the like is formed on the substrate surface and a metal material (for example, copper (Cu)) , Tungsten (W), aluminum (Al), etc.) is suitable for the cleaning treatment after the chemical mechanical polishing (CMP) treatment of the semiconductor wafer.

First, the first step A of the substrate processing method according to the present invention will be described. The first step A is a step of washing while supplying the organic alkaline treatment liquid to both the front and back surfaces of the substrate 1 to remove particles attached to the surface of the substrate 1. As shown in FIG. 3, the substrate cleaning apparatus 2 used in the first step A includes a pair of rotating brushes 3 a and 3 b arranged on the front and back surfaces of the substrate 1, respectively. A cleaning fluid supply nozzle 9 for supplying a cleaning fluid (in this case, an organic alkaline processing liquid) to both front and back surfaces, a driving roller 7 and a holding roller 6a as driving means for holding and rotating the substrate 1
And a holding roller 6e.

The driving roller 6 and the holding rollers 6a to 6e as driving means for rotating the substrate 1 are
A roller member 8a fitted to the shaft member 8c,
A large-diameter stepped portion 8b located below the roller member 8a
And The driving roller 7 has a shaft member 8c connected to driving force applying means (not shown) such as a motor, and is rotatable forward and backward in a direction indicated by an arrow R (or a reverse direction thereof). The holding roller 6e is rotatable about the shaft member 8c in the direction of arrow R and in the opposite direction. The driving roller 7 and the holding roller 6a
At least one of the holding rollers 6e (for example, the holding roller 6a and the holding roller 6e) can be entirely moved in the directions of arrows P and Q by a moving mechanism (not shown), and the substrate 1 is loaded. Sometimes, it moves in the direction of arrow P and retreats, and when the substrate 1 is carried in by the substrate transfer device (only the claw portion 19 is shown in FIG. 4), it moves in the direction of arrow Q and holds the substrate 1 at a predetermined position. In this state, the peripheral portion of the substrate 1 is engaged and held by the driving roller 7 and the holding rollers 6a to 6e, respectively.

The rotating brushes 3a and 3b extend in correspondence with the front and back surfaces of the substrate 1, and the shaft 5a is covered with a brush 5b made of PVA (polyvinyl alcohol) or the like. Are formed with a large number of protrusions 5c. Further, the rotating brushes 3a and 3b are respectively movable in the direction of arrow Z, and the substrate 1 is transferred to the substrate transport device (FIG. 4).
(Only the claw portion 19 is shown), the rotating brush 3a and the rotating brush 3b retract upward and downward, respectively, and when the substrate 1 is held at a predetermined position, each of the rotating brushes 3a and 3b moves in the opposite direction. To contact both sides of the substrate 1. Also,
The rotating brush 3a and the rotating brush 3b are connected to a driving mechanism (not shown), and are configured to be rotationally driven in mutually opposite directions (arrow S and arrow T directions).

Therefore, the driving roller 7 is moved by the driving force applying means (not shown) in the direction of arrow R (or in the opposite direction).
When the substrate 1 is rotated, the substrate 1 is rotationally driven in the direction of the arrow W (or the opposite direction), and in this state, the cleaning fluid (in this case, the organic alkaline processing liquid) is supplied from the cleaning fluid supply nozzle 9
Is dripped, and the rotating brushes 3a and 3b are rotationally driven in opposite directions (the directions of the arrow S and the arrow T), so that the front and back surfaces of the substrate 1 are washed by contacting the protrusions 5c of the rotating brushes 3a and 3b. . When the cleaning with the cleaning fluid (in this case, the organic alkaline processing liquid) is completed, pure water is supplied to both the front and back surfaces of the substrate 1, and the cleaning fluid remaining on the substrate 1 and the substrate 1 are separated from the substrate 1. The removed particles and the like are washed.

When the process of the first step A is completed, the substrate 1
Is carried out by a substrate transfer device (only the claw portion 19 is shown in FIG. 4) and is transferred toward the second step B. The operation of the substrate cleaning apparatus 2 when unloading the substrate 1 is the reverse of the operation when loading the substrate 1, and the basic operation is the same.

Next, the organic alkaline treatment liquid used in the first step A will be described. This organic alkaline processing liquid is non-reactive with metal wiring (eg, copper (Cu), tungsten (W), aluminum (Al), etc.) formed in a state where the metal material is exposed on the surface of the substrate 1. It contains an organic alkali and a complexing agent such as a chelating agent capable of capturing metal impurities as a stable water-soluble complex.
The organic alkaline treatment liquid according to the present invention contains an organic alkali as a main component, preferably contains hydrogen peroxide and water, and has a pH value of more than 7. Since the particles of the metal material used for the metal wiring are generated on the substrate 1 by the CMP, the complexing agent to be added to the organic alkaline processing liquid is exposed to the metal material formed on the surface of the substrate 1. It is preferable to select a compound that easily forms a chelate complex with the particles of and the metal contained in the polishing liquid used.

As the organic alkali, quaternary ammonium salts such as quaternary ammonium hydroxide and organic amines can be used, and it is usually preferable to use 1 to 30% by weight aqueous solution. Representative examples of the quaternary ammonium hydroxide include, but are not limited to, tetramethylammonium hydroxide (TMAH) and trimethyl-2-hydroxyethylammonium hydroxide (choline). As organic amines, trimethylamine,
Tertiary amines such as triethanolamine, diamines such as ethylenediamine, guanidine, toluidine and the like can be used. Two or more of these organic alkalis may be added.

When hydrogen peroxide is mixed with the organic alkaline processing solution, it is usually used as an aqueous solution of 20 to 40% by weight, and the hydrogen peroxide concentration in the whole processing solution is usually 0.01 to 30% by weight. %.

Examples of complexing agents such as chelating agents to be added to the organic alkaline treating solution include fluoride ions, OH groups having a cyclic skeleton in the molecular structure and bonded to carbon atoms constituting the ring. At least one or more substances selected from the group consisting of compounds having one or more O ^- groups are preferred.

When the fluoride ion is added to the organic alkaline treatment liquid, it may be added in any form, but usually it is added as an organic alkali fluoride or ammonium fluoride. The fluoride ion concentration in all the processing solutions is 0.15 mol / l or more, preferably 0.1 mol / l.
At 20 mol / l or more, the upper limit is 2.0 mol / l.

Further, an annular skeleton in the molecular structure an organic alkaline processing liquid, and OH groups and / or O bonded to the carbon atom of the ring ^- adding an organic complexing agent having one or more groups In this case, the total addition amount in the organic alkaline treatment liquid is usually 10 ^{−7 to} 5% by weight, preferably 10 ⁻⁶ % by weight.
It is preferable to add in the range of 0.1 to 0.1% by weight, and the following can be used, but it is not particularly limited thereto. Further, the cyclic skeleton in the molecular structure may be any of an alicyclic compound, an aromatic compound, and a cyclic skeleton corresponding to a heterocyclic compound, and it is sufficient that at least one of these cyclic skeletons is present in the molecular structure. . In addition, although a specific example is illustrated as a compound having an OH group, a corresponding salt such as an ammonium salt is also included. Common names or abbreviations are shown in [] after the compound name.

(1) Phenols having only one OH group and derivatives thereof Phenol, cresol, ethylphenol, t-butylphenol, methoxyphenol, salicyl alcohol, chlorophenol, aminophenol, aminocresol, amidole, p- (2 -Aminoethyl) phenol, salicylic acid, o-salicylanilide, naphthol, naphtholsulfonic acid, 7-amino-4-hydroxy-2-naphthalenedisulfonic acid and the like.

(2) Phenols having two or more OH groups and derivatives thereof Catechol, resorcinol, hydroquinone, 4-methylpyrocatechol, 2-methylhydroquinone, pyrogallol, 1,2,5-benzenetriol, 1,3,3 5-
Benzenetriol, 2-methylphloroglucinol,
2,4,6-trimethylphloroglucinol, 1,2,2
3,5-benzenetetraol, benzenehexaol, tyrone, aminoresorcinol, 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde, dihydroxyacetophenone, 3,4-dihydroxybenzoic acid, gallic acid, 2,3 4-trihydroxybenzoic acid, 2,4-dihydroxy-6-methylbenzoic acid, naphthalene diol, naphthalene triol,
Nitronaphthol, naphthalenetetraol, binaphthyldiol, 4,5-dihydroxy-2,7-naphthalenedisulfonic acid, 1,8-dihydroxy-3,6-naphthalenedisulfonic acid, 1,2,3-anthracentriol, 1,3 , 5-Tris ((2,3-dihydroxybenzoyl) aminomethyl) benzene [MECAM],
1,5,10-tris (2,3-dihydroxybenzoyl) -1,5,10-triazadecane [3,4-LIC
AM], 1,5,9-tris (2,3-dihydroxybenzoyl) -1,5,9-cyclotriazatridecane [3,3,4-CYCAM], 1,3,5-tris ((2 , 3-Dihydroxybenzoyl) carbamide) benzene [3,3,4-CYCAM], 1,3,5-tris ((2,3-dihydroxybenzoyl) carbamide)
Benzene [TRIMCAM], enterobactin, enancycloenterobactin and the like.

(3) Hydroxybenzophenones Dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,6-dihydroxy-4-methoxybenzophenone, 2,2 ′, 5,6′-tetrahydroxybenzophenone, 2,3 ', 4,4', 6-pentahydroxybenzophenone and the like.

(4) Hydroxybenzanilides, such as o-hydroxybenzanilide. (5) Hydroxyanil, such as glyoxalbis (2-hydroxyanil).

(7) Hydroxyquinones and derivatives thereof 2,3-hydroxy-1,4-naphthoquinone, 5-hydroxy-1,4-naphthoquinone, dihydroxyanthraquinone, 1,2-dihydroxy-3- (aminomethyl)
Anthraquinone-N, N'-2 acetic acid [alizarin complexan], trihydroxyanthraquinone and the like.

(8) Diphenyl or triphenylalkane derivatives diphenylmethane-2,2'-diol, 4,4 ',
4 "-triphenylmethanetriol, 4,4'-dihydroxyfuchsone, 4,4'-dihydroxyfuchsone,
4,4'-dihydroxy-3-methylfuchsone, pyrocatechol violet [PV] and the like.

(9) Phenol derivative of alkylamine Ethylenediaminediorthohydroxyphenylacetic acid [E
DDHA], N, N-bis (2-hydroxybenzyl)
Ethylenediamine-N, N-2acetic acid [HBED], ethylenediaminedihydroxymethylphenylacetic acid [EDD
HMA] etc. (10) Phenol derivative of alkyl ether 3,3′-ethylenedioxydiphenol and the like.

(11) Azo-containing phenols and derivatives thereof 4,4'bis (3,4-dihydroxyphenylazo)-
Diammonium 2,2'-stilbenedisulfonic acid [stilbazo], 2,8-dihydroxy-1- (8-hydroxy-3,6-disulfo-1-naphthylazo) -3,6
-Naphthalenedisulfonic acid, o, o'-dihydroxyazobenzene, 2-hydroxy-1- (2-hydroxy-
5-methylphenylazo) -4-naphthalenesulfonic acid [calmagite], chlorohydroxyphenylazonaphthol, 1 ′, 2-dihydroxy-6-nitro-1,
2'-azonaphthalene-4-sulfonic acid [Eriochrome Black T], 2-hydroxy-1- (2-hydroxy-4-sulfo-1-naphthylazo) -3,6-naphthalenedisulfonic acid, 5-chloro-2 -Hydroxy-3-
(2,4-dihydroxyphenylazo) benzenesulfonic acid [lumogallion], 2-hydroxy-1- (2-hydroxy-4-sulfo-1-naphthylazo) -3-naphthalene acid [NN], 1,8-dihydroxy- 2- (4-
Sulfophenylazo) -3,6-naphthalenedisulfonic acid, 1,8-dihydroxy-2,7-bis (2-sulfophenylazo) -3,6-naphthalenedisulfonic acid, 2
-[3- (2,4-dimethylphenylaminocarboxy) -2-hydroxy-1-naphthylazo] -3-hydroxybenzenesulfonic acid, 2- [3- (2,4-dimethylphenylaminocarboxy) -2-hydroxy -1
-Naphthylazo] phenol and the like.

(12) Heterocyclic compounds having an OH group and derivatives thereof 8-quinolinol, 2-methyl-8-quinolinol, quinolinediol, 1- (2-pyridineazo) -2-naphthol, 2-amino-4 , 6,7-pteridinetriol, 5,7,3 ', 4'-tetrahydroxyflavone [luteolin], 3,3'-bis [N, N-bis (carboxymethyl) aminomethyl] fluorescein [calcein], 2, , 3-hydroxypyridine and the like.

(13) Alicyclic compounds having an OH group and derivatives thereof Cyclopentanol, croconic acid, cyclohexanol, cyclohexanediol, dihydroxydiquinoyl, tropolone, 6-isopropyltropolone and the like.

The organic complexing agent selected from the group consisting of the above (1) to (13) is at least one or more in consideration of the cost of the complexing agent and the chemical stability in the added organic alkaline treatment solution. In terms of metal adhesion preventing effect, phenol derivatives of alkylamines such as ethylenediamine diorthohydroxyphenylacetic acid [EDDHA], phenols having two or more OH groups such as catechol and tyrone and derivatives thereof may be added. Are better.

Further, when a second complexing agent having a metal ligand is added in addition to the organic complexing agent selected from the group consisting of the above (1) to (13), the effect of preventing metal adhesion is improved. And
More preferred. Hereinafter, compounds added as the second complexing agent will be exemplified, but are not particularly limited thereto. In the following description, the donor atom is
An atom that can supply electrons required for coordination bond with a metal.

[0051] As [A] a complexing agent having sulfur or carbon as a donor atom (14) complexing agent coordinating groups having sulfur donor atoms, wherein _{^{HS -, S 2-, S 2}} O 3 2- , RS ^-, R-
COS ^- is selected from, or CS ₃ ^2-in has at least one of the groups represented, or RSH, R 'thiol represented by ₂ S or R ₂ C = S, sulfide or thiocarbonyl compounds ^-, R-CSS There is something. Here, R represents an alkyl group, R ′ represents an alkyl group or an alkenyl group, and may be further linked to each other to form a ring containing a sulfur atom. Specifically, the HS ^- group or S
Hydrogen sulfide or a salt thereof having a ^2- group or a sulfide such as ammonium sulfide; thiosulfuric acid or a salt thereof having an S ₂ O ₃ ^2- group; thiol or ethane having a RSH or RS ⁻ group Lower alkyl thiols such as thiol and 1-propanethiol or salts thereof;
Thioacetic acid, dithiooxalic acid or a salt thereof having a COS ^- group; ethanedibis (dithioic acid), dithioacetic acid or a salt thereof having an R-CSS ^- group; CS ₃
As having a group having a ^2-group, trithiocarbonate carbonate or a salt thereof; a sulfide represented by R _'2 S, methyl sulfide, methyl thio ethane, diethyl sulfide, vinyl sulfide,
Benzothiophene and the like; thiocarbonyl compounds represented by R ₂ C = S groups include propanethione, 2,4-pentanedithione and the like.

[0052] (15) as a complexing agent coordinating groups having carbon as a donor ^atom, NC - those having a ^-, RNC, RCC. For example, cyanides such as hydrogen cyanide and ammonium cyanide, isocyanides such as ethyl isocyanide, allylene, metal acetylide and the like.

[B] Complexing agents having nitrogen as a donor atom include the following (16) to (29). (16) Monoamines Ethylamine, isopropylamine, vinylamine, diethylamine, dipropylamine, N-methylethylamine, triethylamine, benzylamine, aniline,
Toluidine, ethylaniline, xylidine, thymilamine, 2,4,6-trimethylaniline, diphenylamine, N-methyldiphenylamine, biphenylylamine, benzidine, chloroaniline, nitrosoaniline,
Aminobenzenesulfonic acid, aminobenzoic acid and the like.

(17) Diamines and polyamines Ethylenediamine, propylenediamine, trimethylenediamine, hexamethylenediamine, diethylenetriamine, diaminobenzene, toluenediamine, N-methylphenylenediamine, triaminobenzene, aminodiphenylamine, diaminophenylamine and the like.

(18) Amino alcohols Ethanolamine, 2-amino-1-butanol, 2-
Amino-2-methyl-1-propanol, 2-amino-
2-ethyl-1,3-propanediol, 2- (ethylamino) ethanol, 2,2′-iminodiethanol,
Dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, 3-diethylamino-
1,2-propanediol, triethanolamine and the like.

(19) Aminophenols Aminophenol, p-aminophenol sulfate, (methylamino) phenol, aminoresorcinol and the like.

(20) Amino acids glycine, glycine ethyl ester, sarcosine, alanine, aminobutyric acid, norvaline, valine, isovaline, norleucine, leucine, isoleucine, serine, L-threonine, cysteine, cystine, methionine, ornithine, lysine, arginine , Citrulline, aspartic acid, asparagine,
Glutamic acid, glutamine, β-hydroxyglutamic acid, N-acetylglycine, glycylglycine, diglycylglycine, phenylalanine, tyrosine, L-thyroxine, N-phenylglycine, N-benzoylglycine and the like.

(21) Iminocarboxylic acids Imino diacetic acid, nitrilo triacetic acid, nitrilo 3 propionic acid, ethylenediamine diacetic acid [EDDA], ethylenediamine tetraacetic acid [EDTA], hydroxyethylethylenediamine tetraacetic acid [EDTA-OH], trans-1 , 2
-Diaminocyclohexanetetraacetic acid [CyDTA], dihydroxyethylglycine [DHGE], diaminopropanoltetraacetic acid [DPTA-OH], diethylenetriaminepentaacetic acid [DTPA], ethylenediamine2propiondiacetic acid [EDDP], glycol etherdiaminetetraacetic acid [GEDTA] 1,6-hexamethylenediamine 4
Acetic acid [HDTA], hydroxyethyl imino diacetic acid [H
IDA], methyl EDTA (diaminopropane tetraacetic acid), triethylenetetramine hexaacetic acid [TTHA],
3,3'-dimethoxybenzidine-N, N, N ', N'
-4 acetic acid and the like.

(22) Iminophosphonic acids Ethylenediamine-N, N'-bis (methylenephosphonic acid) [EDDPO], ethylenediaminetetrakis (methylenephosphonic acid) [EDTPO], nitrilotris (methylenephosphonic acid) [NTPO], diethylenetriaminepenta ( Methylene phosphonic acid) [ETTPO],
Propylenediaminetetra (methylenephosphonic acid) [P
DTMP].

(23) Heterocyclic amines pyridine, coniline, lutidine, picoline, 3-pyridinol, isonicotinic acid, picolinic acid, acetylpyridine, nitropyridine, 4-pyridone, bipyridyl, 2,
4,6-tris (2-pyridyl) -1,3,5-triazine [TPTZ], 3- (2-pyridyl) -5,6-bis (4-sulfonyl) -1,2,4-triazine [P
Pyridines such as DTS], syn-phenyl-2-pyridylketoxime [PPKS], quinoline, quinaldine, lepidine, dimethylquinoline, 8-quinolinol,
Quinolines such as 2-methyl-8-quinolinol, methoxyquinoline, chloroquinoline, quinoline diol, quinaldic acid, quinic acid, nitroquinoline, quinulin, kynurenic acid, 8-acetoxyquinoline and bicinchoninic acid;
Isoquinolines, acridine, 9-acridone, phenanthridine, benzoquinoline, benzoquinolines such as benzoisoquinoline, naphthoquinolines such as naphthoquinoline, o-phenanthroline, 2,9-dimethyl-
1,10-phenanthroline, bathocuproine, bathocuproine sulfonic acid, bathophenanthroline, bathophenanthroline sulfonic acid, 2,9-dimethyl-4,7-
Phenanthrolines such as diphenyl-1,10-phenanthroline, pyrazoles such as pyrazole and 5-pyrrolozone, imidazoles such as imidazole and methylimidazole, 2-imidazolines, imidazolines and imidazolidines such as ethyleneurea, benzimidazole Benzimidazoles, such as
Diazines such as diazine, pyrimidine and pyrazine, hydropyrimidines such as uracil and thymine, piperazines such as piperazine, benzodiazines and dibenzodiazines such as cinnoline and phenazine, triazines, purines, oxazole, 4-oxazolone, iso Oxazoles and isoxazoles such as oxazole and azoxime, oxazines such as 4H-1,4-oxazine and morpholine, thiazoles and benzothiazoles, isothiazoles, thiazines, pyrroles, pyrrolines and pyrrolidines, indoles, Indolines, isoindoles, carbazoles, indigo, porphyrins and the like.

(24) Amides and imides Carbamic acid, ammonium carbamate, oxamic acid, ethyl oxamate, ethyl N-nitrocarbamate, carbanilic acid, carbanilonitrile, oxanilic acid, formamide, diacetamide, hexaneamide,
Acrylamide, lactamide, cyanoacetamide, oxamide, succinamide, salicylamide, nitrobenzamide, succinimide, maleimide, phthalimide, and the like.

(25) Anilides Formanilide, acetanilide, hydroxyanilide, chloroanilide, methoxyacetanilide, oxanilide and the like.

(26) Urea, thiourea and derivatives thereof urea, N-methylurea, N, N'-ethylideneurea, allophanoic acid, glycolic acid, oxalic acid, biuret, N-nitrourea, azodicarbonamide, thiourea , Methylthiourea, dimethylthiourea and the like. (27) Oximes Formaldoxime, p-benzoquinonedioxime, benzaldoxime, benzyldioxime and the like.

(28) Those having a coordination group in which nitrogen atoms are bonded to each other: hydrazine such as azobenzene, azotoluene, methyl red, azobenzenedicarboxylic acid, hydroxyazobenzene, azoxybenzene, and hydrazides; phenylhydrazine, p-bromophenylhydrazine , P
Azo and azoxy compounds such as -nitrophenylhydrazine and N ',-phenylacetohydrazide; hydrazo compounds such as hydrazobenzene and hydrazodibenzoic acid; oxalic bis (salicylidenehydrazide); (Carboxyphenyl) hydrazone, benzaldehyde hydrazone, hydrazones such as acetaldehyde phenylhydrazone, azines such as benzylideneazine, azides such as benzoyl azide, diazonium salts such as benzenediazonium chloride, diazo compounds such as benzenediazohydroxide, semicarbazide and the like And thiosemicarbazides such as thiosemicarbazide.

(29) Others Azides such as ammonium azide and sodium azide, nitriles such as acetonitrile, amide sulfate, imide disulfate, nitride trisulfate, thiocyanic acid, ammonium thiocyanate and the like.

[C] Complexing agents having a carboxyl group as a metal coordinating group include the following (30) to (33). (30) Monocarboxylic acids Formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid,
Decanoic acid, undecanoic acid, dodecanoic acid, stearic acid,
Acrylic acid, crotonic acid, oleic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, fluoroacetic acid, benzoic acid, methylbenzoic acid, chlorobenzoic acid, nitrobenzoic acid, sulfocarboxylic acid, phenylacetic acid and the like.

(31) Polycarboxylic acids: oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, 1,2,3-propanetricarboxylic acid, chlorosuccinic acid, phthalic acid, 1,3,5-benzenetricarboxylic acid, Dichlorophthalic acid, nitrophthalic acid, phenylsuccinic acid and the like.

(32) Hydroxymonocarboxylic acids having 4 or less hydroxyl groups As those having one hydroxyl group, glycolic acid, lactic acid,
As those having two hydroxyl groups such as 2-hydroxybutyric acid, hydroacrylic acid, hydroxybenzoic acid, salicylic acid, and sulfosalicylic acid, glyceric acid, 8,9-dihydroxystearic acid, 2,4-dihydroxybenzoic acid,
As having three hydroxyl groups, such as protocatechuic acid,
Gallic acid and the like.

(33) Hydroxy dicarboxylic acids having 4 or less hydroxyl groups As those having one hydroxyl group, two hydroxyl groups such as tartronic acid, malic acid, 2-hydroxybutane diacetic acid, 2-hydroxy dodecane diacetic acid, and hydroxyphthalic acid are used. Those having four hydroxyl groups, such as tartaric acid and 3,4-dihydroxyphthalic acid, and tetrahydroxysuccinic acid.

[D] Complexing agents having a carbonyl group as a metal coordinating group include the following (34) to (41). (34) aliphatic aldehydes formaldehyde, acetaldehyde, propionaldehyde, isobutyraldehyde, acrylaldehyde,
Crotonaldehyde, chloroacetaldehyde, dichloroacetaldehyde, butylchloral, hydroxyacetaldehyde, lactaldehyde, D-glyceraldehyde, formal, acetal, dichloroacetal and the like.

(35) Aliphatic ketones Acetone, ethyl methyl ketone, 2-methylpentanone, 3-pentanone, 3-methyl-2-butanone, 4-
Methyl-2-pentanone, pinacolin, 2-heptanone, 3-heptanone, 4-heptanone, 6-methyl-heptanone, diisobutyl ketone, di-tert-butyl ketone, dihexyl ketone, methyl vinyl ketone, allyl acetone, 1-chloro- 2-propanone, 1,1-dichloro-2-propanone, hydroxyacetone, dihydroxyacetone and the like.

(36) Polyoxo compounds Di- and polyaldehydes such as glyoxal, malonaldehyde and succinaldehyde, di- and polyketones such as diacetyl, acetylacetone and acetonylacetone, and keto such as pyruvaldehyde and 4-oxopentanal. Aldehydes and the like.

(37) Ketene Ketene, dimethylketene and the like. (38) Ketocarboxylic acids and aldehyde carboxylic acids 4,4,4-trifluoro-1-phenyl-1,3-butanedione, 2,2,6,6-tetramethyl-3,5-
Heptanedione, pyruvic acid, malonaldehyde acid, acetoacetic acid, glyoxylic acid, mesooxalic acid, oxaloacetic acid, oxalogultaric acid and the like.

(39) Aromatic aldehydes and aromatic ketones Benzaldehyde, tolualdehyde, phenylacetaldehyde, cinnamaldehyde, terephthalaldehyde, protocatechualdehyde, acetophenone, methylacetophenone, benzophenone, chloroacetophenone, dihydroxybenzophenone, phenylglyoxal and the like.

(40) Quinones o-benzoquinone, p-benzoquinone, naphthoquinone,
Quinhydrone, 2,6-dichloro-p-benzoquinone,
2,5-dihydroxy-p-benzoquinone, tetrahydroxy-p-benzoquinone, 2,3-hydroxy-1,
4-naphthoquinone and the like. (41) Tropolones Tropolone, 6-isopropyltropolone and the like.

The organic alkaline processing liquid used in the first step A has no corrosiveness to metals (for example, copper (Cu), tungsten (W), aluminum (Al), etc.), and is a stable aqueous solution of metal impurities. Since it contains a complexing agent such as a chelating agent that can be trapped as an acidic complex, it is formed in a state where a metal material (for example, copper (Cu), tungsten (W), aluminum (Al), etc.) is exposed on the surface of the substrate 1. The surface of the metal wiring thus formed is not roughened, and the metal impurity ions are prevented from adhering to the surface of the substrate 1, thereby achieving a high cleaning effect on particles adhering to the substrate surface. The complexing agent and the second complexing agent contained in the organic alkaline treating solution according to the present invention effectively act on metal particles and ions to form a complex, but the substrate is strongly bonded to the metal. 1 does not easily form a complex with the metal wiring itself, and has no corrosiveness.

Next, the second step B of the substrate processing method according to the present invention will be described. As shown in FIGS. 1 and 2,
The second step B is a step of cleaning while supplying the organic acid treatment liquid to both the front and back surfaces of the substrate 1 to remove metal impurities attached to the surface of the substrate 1. Note that the second step B includes:
Only the cleaning fluid (in this case, the organic acid treatment liquid) used in the first step A is different, and the configuration and operation of the substrate cleaning apparatus 2 used in the second step B are the same. The detailed description of is omitted.

The substrate 1 processed in the first step A is carried into the substrate cleaning apparatus 2 in the second step B by a substrate transfer device (only the claws 19 are shown in FIG. 4). When the substrate 1 is held at a predetermined position of the substrate cleaning apparatus 2, a cleaning fluid (in this case, an organic acid treatment liquid) is dropped from the cleaning fluid supply nozzle 9, and the rotating brush 3 a Cleaning is performed by contact of the protrusion 5c of 3b. When the cleaning with the cleaning fluid (in this case, the organic acid treatment liquid) is completed, pure water is supplied to both the front and back surfaces of the substrate 1 and separated from the cleaning fluid remaining on the substrate 1 and the substrate 1. The removed metal impurities and the like are washed. When the processing in the second step B is completed, the substrate 1 is unloaded by the substrate transfer device (only the claw portions 19 are shown in FIG. 4) and is transferred toward the third step C.

The organic acid processing solution used in the second step B is formed in a state where a metal material (for example, copper (Cu), tungsten (W), aluminum (Al), etc.) is exposed on the surface of the substrate 1. And a complexing agent such as a chelating agent capable of capturing metal impurities as a stable water-soluble complex. The organic acid treatment liquid according to the present invention contains an organic acid as a main component and has a pH value of less than 7.

As the organic acid, carboxylic acids can be used, and at least one selected from the group consisting of oxalic acid, citric acid, malic acid, maleic acid, succinic acid, tartaric acid, malonic acid and salts thereof. Preferably, it is a compound. On the substrate 1, particles of the metal material used for the metal wiring may be oxidized by CMP to generate metal oxide particles, and the organic acid may be exposed on the surface of the substrate 1. It is preferable to select a compound that easily forms a chelate complex with the oxide particles of, for example, when copper metal wiring is exposed on the surface of the substrate 1, the copper oxide particles (CuO _x ) and the chelate complex Oxalic acid, which has a high effect of forming phenol, is preferred. Note that the carboxylic acids hardly form a complex with the metal wiring itself that is strongly bonded to the metal, and have no corrosiveness. Further, the barrier film 52 (titanium (Ti), titanium nitride (TiN), etc.) formed on the substrate 1 does not form a complex with these carboxylic acids and is not corroded. In addition, the carboxylic acids are contained in 0.1.
It is preferably used as an aqueous solution of 01 to 5% by weight.

As a complexing agent such as a chelating agent to be added to the organic acid treatment solution, metal impurities remaining as particles or ions on the substrate 1 after the CMP treatment (for example, the polishing solution used or the substrate (K), calcium (Ca), titanium (Ti), copper (C)
u), zinc (Zn), etc.), and polyaminocarboxylic acids and ammonium fluoride, which easily form a complex with zinc (Zn). Examples of polyaminocarboxylic acids include ethylenediaminetetraacetic acid (EDTA), trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA), nitrilotriacetic acid (NTA), and diethylenetriaminepentaacetic acid (DTP).
A), compounds such as N- (2-hydroxyethyl) ethylenediamine-N, N ', N'-triacetic acid (EDTA-OH) and salts thereof are preferable, and ammonium salts which do not adversely affect the properties of semiconductors are particularly preferable. Metal-free salts of are preferred. The concentration of the complexing agent is preferably 1 to 10000 ppm, more preferably 10 to 1000 ppm, based on the organic acid treatment solution.

The organic acid treatment solution used in the second step B includes a metal (for example, copper (Cu), tungsten (W),
(Aluminum (Al), etc.) is not corrosive, and contains a complexing agent such as a chelating agent capable of capturing metal impurities as a stable water-soluble complex. It does not corrode the surface of the metal wiring and has a high cleaning effect on metal impurities attached to the surface of the substrate 1. The complexing agent contained in the organic acid treatment solution according to the present invention effectively acts on metal particles and ions to form a complex. On the other hand, it does not easily form a complex and has no corrosiveness.

In the present embodiment, first, the treatment with the organic alkaline treatment liquid in the first step A is performed, and then,
Although the treatment with the organic acid treatment liquid in the second step B is performed, the treatment is not necessarily limited to this order. That is, the first step A and the second step B are reversible, and the substrate 1 may be first treated with an organic acidic treatment liquid and then treated with an organic alkaline treatment liquid. This is because the organic alkaline processing liquid according to the present invention has no corrosiveness to metals (eg, copper (Cu), tungsten (W), aluminum (Al), etc.) and can capture metal impurities as a stable water-soluble complex. Since it contains a complexing agent such as a chelating agent, pits are not generated in the metal wiring formed on the surface of the substrate 1 and the substrate 1
Based on the absence of metal impurity ions attached to the surface. Therefore, the substrate processing method according to the present invention has a high degree of freedom in setting a substrate processing step.

Next, the third step C of the substrate processing method according to the present invention will be described. The third step C is a step in which the front and back surfaces of the substrate 1 treated in the second step B are finish-cleaned by ultrasonic waves and then dried, and the substrate 1 treated in the second step B is As shown in FIG. 4, each of the substrates is gripped one by one by the claws 19 of the substrate transfer device, and is carried into the ultrasonic cleaning device 12 in the third step C. Ultrasonic cleaning apparatus 12 used in the third step C of the substrate processing method according to the present invention
A holding table 13 fixedly holding the substrate 1, and a plurality of needle-like holding pins 1 provided on the holding table 13 to support the substrate 1.
3b, a hook-shaped chuck member 14 that engages with the peripheral edge of the substrate 1, and a cleaning fluid jet that supplies an ultrasonic cleaning fluid (in this case, pure water) to the substrate 1 by exciting the ultrasonic cleaning fluid. And a nozzle (ultrasonic nozzle) 17. The holding means 13, the holding pins 13 b and the chuck member 14 constitute a fixing means for the substrate 1.

The holding table 13 is formed in a disk shape.
The peripheral portion is formed at least higher than the surface of the substrate 1, and serves as a convex portion 13a for preventing scattering of the ultrasonic cleaning fluid (in this case, pure water). A discharge duct 23 for discharging the ultrasonic cleaning fluid during or after cleaning is provided on the inner peripheral side of the convex portion 13a. In the present embodiment,
Although the discharge duct 23 is provided at two places, the discharge duct 23 may be provided at at least one place.

The holding pin 13b is made of a needle-like member.
The back surface of the substrate 1 is supported at one point to prevent contamination on the back surface side of the substrate 1, and is disposed at, for example, four locations (only two locations are shown in FIG. 4) at equal intervals. In addition, the chuck members 14 are provided at four locations (only two locations are shown in FIG. 4) at equal intervals along the circumference of the substrate 1. The chuck member 14 can be opened and closed by an opening / closing mechanism (not shown) from a position indicated by a two-dot line to a position indicated by a solid line, and receives the substrate 1 from above in an open state (the position indicated by the two-dot line). Is closed on the holding pin 13b (at the position indicated by the solid line), the peripheral edge of the substrate 1 is engaged and held and fixed. Therefore, in this state, the substrate 1 processed in the second processing step B in the preceding stage is fixed by the holding table 13, the holding pins 13 b and the chuck member 14. The holding pin 13
b and the chuck member 14 may be provided in at least three places.

A shaft member 15 is connected at one end to the center of the back side of the holding table 13. The other end of the shaft member 15 is connected to rotation driving means (not shown),
Numeral 5 is rotatable forward and backward (for example, rotated in the direction of arrow V) by a rotation drive unit. A cleaning fluid supply path 24a for supplying an ultrasonic cleaning fluid (pure water in this case) toward the back surface of the substrate 1 is formed at the center of rotation of the shaft member 15, and the center of the holding table 13 is formed. A cleaning fluid ejection port 24b for the back surface is provided therethrough. The rotation speed of the shaft member 15 is, for example, 1800 to 2000 r. p. m (revolution per minute), and the holding table 13 can rotate at a high speed in the direction of the arrow V (or the opposite direction).

Cleaning Fluid Injection Nozzle (Ultrasonic Nozzle) 1
Reference numeral 7 includes an ultrasonic oscillator (not shown) connected to an oscillator, and when an ultrasonic cleaning fluid (in this case, pure water) is supplied, the oscillator and the ultrasonic oscillator are connected. Driving at a predetermined frequency, ultrasonic cleaning fluid (in this case, pure water)
And is ejected toward the substrate 1. Further, the cleaning fluid jet nozzle (ultrasonic nozzle) 17 can be moved in directions of arrows F and G by a moving mechanism (not shown),
If the cleaning fluid jet nozzle (ultrasonic nozzle) 17 is moved, the ultrasonic cleaning fluid excited by the ultrasonic vibration can be jetted evenly toward the entire surface of the substrate 1. The driving frequency of the ultrasonic transducer (not shown) is as follows.
A frequency of 500 kHz or more can be used, and in this embodiment, the driving frequency is 950 kHz, which is a high-megasonic-compatible device.

Therefore, the holding table 1 to which the substrate 1 is fixed
3 is rotated in the direction of arrow V (or the opposite direction) by a rotary drive means (not shown), and the cleaning fluid jet nozzle (ultrasonic nozzle) 17 is supplied with an ultrasonic cleaning fluid (pure water in this case).
When the oscillator and the ultrasonic transducer (not shown) are driven, the surface of the substrate 1 can be precisely cleaned with the ultrasonic cleaning fluid excited by the ultrasonic wave. At this time, the cleaning fluid injection nozzle (ultrasonic nozzle)
By spraying the ultrasonic cleaning fluid while moving 17 in the direction of arrow F, the entire surface of the substrate 1 can be cleaned evenly. In addition, since the powerful ultrasonic wave applied to the front surface of the substrate 1 propagates also to the back surface of the substrate 1, the ultrasonic cleaning is performed through the cleaning fluid supply path 24a and the back surface cleaning fluid jet port 24b. If the working fluid (in this case, pure water) is supplied to the back surface of the substrate 1, the front and back surfaces of the substrate 1 can be simultaneously ultrasonically cleaned.

The dishing 55 generated on the metal wiring 51 on the substrate 1 such as a semiconductor wafer by the ultrasonic cleaning.
Particles, metal impurities, and the like adsorbed in the step portion 56 (see FIG. 8) can be reliably cleaned, and the front and back surfaces of the substrate 1 can be precisely cleaned to improve cleanliness. When the cleaning with the ultrasonic cleaning fluid (pure water in this case) excited by the ultrasonic wave is completed, pure water is supplied to both the front and back surfaces of the substrate 1 while the rotation of the holding table 13 is maintained, The ultrasonic cleaning fluid remaining on the substrate 1 and particles and metal impurities separated from the substrate 1 are cleaned. In the present embodiment, a high cleaning effect is obtained by injecting the ultrasonic cleaning fluid (in this case, pure water) by exciting with ultrasonic waves. And a cleaning fluid such as pure water may be pressurized and ejected.

When the cleaning of the front and back surfaces of the substrate 1 is completed, the supply of pure water is stopped, and the holding table 13 is continuously rotated for a predetermined time, and the pure water remaining on the front and back surfaces of the substrate 1 is centrifuged by high-speed rotation. Disperse by force and dry. At this time, as shown in FIG. 2, if dry nitrogen (N ₂ ) gas or the like is sprayed on both the front and back surfaces of the substrate 1, metal wiring (eg, copper (Cu), tungsten (W)) formed on the surface of the substrate 1 is formed. (W), aluminum (Al) and the like can be prevented from being oxidized and the drying time can be shortened, which is preferable.

When the processing in the third step C is completed, the substrate 1
Is carried out by the claw portion 19 of the substrate transfer device and transferred to a subsequent process. Note that the operation of the ultrasonic cleaning device 12 when unloading the substrate 1 is the reverse of the operation when the substrate 1 is unloaded, and the basic operation is the same.

Next, the processing effects of the substrate processing method according to the present invention will be described with reference to FIGS. 5 (a) and 5 (b). FIG. 5A is a diagram showing the processing effect on particles by the substrate processing method according to the present invention, in which the horizontal axis indicates the cleaning time and the vertical axis indicates the number of particles. FIG.
(B) is a diagram showing a processing effect on metal impurities by the substrate processing method according to the present invention, in which the horizontal axis represents cleaning time and the vertical axis represents metal impurity concentration (atoms / cm ² ).

First, the effects of the substrate processing method according to the present invention on particles will be described with reference to FIG. The particles were measured by using at least 10,000 particles adhered to an 8-inch substrate (semiconductor wafer) as a sample, and the cleaning time in each of the first process A to the third process was measured. The treatment was carried out at 20 seconds and 60 seconds, and the number of particles of 0.2 μm or more in each cleaning time was measured using a laser reflection type surface foreign matter inspection device (SP1). FIG. 5A shows a first step A (treatment with an organic alkaline treatment liquid), a second step B (treatment with an organic acid treatment liquid), and a third step C (ultrasonic cleaning with pure water). (Drying) is sequentially processed in this order.

As shown in FIG. 5A, the initial value is 100
If the substrate on which 00 or more particles are adhered is washed at least for 20 seconds in each of the first step A to the third step C, the number of particles is reduced to almost 0, and a high cleaning effect is obtained in a short time. Is obtained.

Next, the effect of the substrate processing method according to the present invention on metal impurities will be described with reference to FIG. The measurement of the metal impurity concentration is performed on an 8-inch substrate (a semiconductor wafer in which copper (Cu) metal wiring is formed on the substrate surface by CMP, also referred to as Cu-CMP).
And copper (Cu) or iron (Fe) adhered thereto are used as test specimens, and the cleaning time in the first to third processing steps is set to 20 seconds and 60 seconds, respectively. And the metal impurity concentration (at
oms / cm ² ) using a total reflection X-ray fluorescence spectrometer (TXR
It measured using F). FIG. 5B shows a first step A (treatment with an organic alkaline treatment liquid), a second step B (treatment with an organic acid treatment liquid), and a third step C (ultrasonic cleaning and treatment with pure water). (Drying) is sequentially processed in this order.

As shown in FIG. 5B, the initial value is 1.0
Copper (Cu) contamination having a concentration of not less than × 10 ¹¹ (atoms / cm ² ) and 1.0 × 10 ¹² (atoms / cm ² )
The iron (Fe) contamination having a concentration of not less than m ² ) can be detected by washing at least for 20 seconds in each of the first step A to the third step C, and the detection limit value (1.0 × 10 ¹⁰ ( ato
ms / cm ² )), which indicates that a high cleaning effect can be obtained in a short time.

Comparative Example 1 Next, the cleaning effect on metal impurities when only the organic alkaline treatment liquid according to the present invention is used alone will be described with reference to FIGS. 6 (a) and 6 (b). FIG. 6 (a) is a view showing a treatment effect on copper (Cu) contamination when the organic alkaline treatment liquid according to the present invention is used alone, and FIG. It is a figure which shows the processing effect with respect to the iron (Fe) contamination in the case, and a horizontal axis | shaft shows a cleaning time, and a vertical axis | shaft shows metal impurity concentration (atoms / cm < ² >), respectively.

The measurement of the metal impurity concentration was performed when the substrate body (silicon (Si)) was exposed (B in FIG. 6).
are described below) and two types of 8-inch substrates (semiconductor wafers) each having an oxide film (SiO ₂ ) formed on the substrate body (denoted as SiO _{2 in} FIG. 6).
u) (FIG. 6 (a)) or iron (Fe) (FIG. 6 (b)) is used as a sample, and the cleaning time is reduced to 20 seconds and 60 seconds using only an organic alkaline treatment solution. The processing is performed by setting, and the metal impurity concentration (a
toms / cm ² ) using a total reflection X-ray fluorescence spectrometer (TXR
It measured using F).

First, the treatment effect on copper (Cu) contamination when the organic alkaline treatment solution according to the present invention is used alone will be described with reference to FIG. FIG.
As shown in (a), the initial value is 1.0 × 10 ¹² (ato
ms / cm ² ) or more,
Although the cleaning time tends to decrease as the cleaning time becomes longer, a sufficient cleaning effect is obtained particularly in the sample in which the substrate body (silicon (Si)) is exposed (denoted by Bare in FIG. 6). It turns out that it has not been obtained. In FIGS. 6A and 6B, D.E. L indicates that the value was below the detection level (Detection Level).

On the other hand, the treatment effect on iron (Fe) contamination when the organic alkaline treatment liquid according to the present invention is used alone will be described with reference to FIG. FIG.
As shown in (b), the initial value is 1.0 × 10 ¹¹ (ato
ms / cm ² ) or more,
Although the cleaning time tends to decrease as the cleaning time becomes longer, it is particularly sufficient for a sample in which an oxide film (SiO ₂ ) is formed on the substrate body (denoted as SiO _{2 in} FIG. 6). It can be seen that the cleaning effect was not obtained.

Therefore, it can be seen that the use of the organic alkaline treatment liquid according to the present invention alone alone does not provide a sufficient cleaning effect particularly on metal impurities.

(Comparative Example 2) Next, regarding the treatment effect on particles when each of the organic acid treatment solution, organic alkaline treatment solution and pure water according to the present invention was used alone,
This will be described with reference to FIG. FIG. 7 is a diagram showing the processing effect on particles when the organic acidic processing liquid, organic alkaline processing liquid and pure water according to the present invention are used alone. The particles were measured by using an organic acid treatment solution, an organic alkali treatment solution, and pure water according to the present invention on a sample in which at least 10,000 particles were adhered to an 8-inch substrate (semiconductor wafer). After treating with the cleaning time set to 20 seconds, the number of particles of 0.2 μm or more was measured using a laser reflection type surface foreign matter inspection device (SP1).

As shown in FIG. 7, it can be seen that the organic alkaline processing liquid according to the present invention has a predetermined effect on particles even when used alone. It can be seen that the use of only A alone does not provide a sufficient cleaning effect particularly on particles.

That is, (Comparative Example 1) and (Comparative Example 2)
As is evident from the above, the substrate 1 cannot be washed with a high degree of cleanliness by using only one of the organic alkaline treatment liquid and the organic acid treatment liquid according to the present invention alone,
First, in a first step A, the substrate 1 is treated using an organic alkaline treatment liquid (or an organic acid treatment liquid), and then, in a second step B, the substrate 1 is treated with an organic acid treatment liquid (or an organic alkaline treatment liquid). It can be seen that the substrate processing method of the present invention in which processing is performed on the substrate 1 that has been processed in the first step A is effective in improving the cleaning effect of the substrate 1.

In particular, the organic alkaline treatment liquid and the organic acid treatment liquid according to the present invention have no corrosiveness to metals (for example, copper (Cu), tungsten (W), aluminum (Al), etc.) and stabilize metal impurities. Since a complexing agent such as a chelating agent that can be trapped as a water-soluble complex is contained, the metal wiring formed by being exposed on the surface of the substrate 1 is not corroded. Accordingly, particles and metal impurities attached to the surface of the substrate 1 can be removed with high efficiency.

Further, in the substrate processing method according to the present invention, in the third step C, the substrate 1 processed in the second step B is subjected to finish cleaning by ultrasonic waves.
Dishing 55 and step 56 generated in the metal wiring 51
(See FIG. 8) A high cleaning effect can be obtained even for particles and metal impurities adsorbed in the substrate 1, and the first step A to the third step C can be performed consistently to clean the substrate 1. It is possible to further improve the degree.

[Brief description of the drawings]

FIG. 1 is a flowchart showing steps of a substrate processing method according to the present invention.

FIG. 2 is a diagram showing processing steps of a substrate processing method according to the present invention.

FIG. 3 is a perspective view showing a substrate cleaning apparatus used in the substrate processing method according to the present invention.

FIG. 4 is a cross-sectional view of the ultrasonic cleaning apparatus used in the substrate processing method according to the present invention as viewed from the front.

FIG. 5A is a diagram showing a processing effect on particles by the substrate processing method according to the present invention, in which the horizontal axis represents cleaning time and the vertical axis represents the number of particles. (B) is a diagram showing a processing effect on metal impurities by the substrate processing method according to the present invention, in which the horizontal axis represents cleaning time and the vertical axis represents metal impurity concentration (atoms / cm ² ).

FIG. 6 (a) is a view showing a treatment effect on copper (Cu) contamination when the organic alkaline treatment liquid according to the present invention is used alone, and FIG. 6 (b) is a graph showing the organic alkaline treatment liquid according to the present invention alone. It is a figure which shows the processing effect with respect to iron (Fe) contamination when it is used, and a horizontal axis | shaft shows a cleaning time and a vertical axis | shaft respectively shows a metal impurity concentration (atoms / cm < ² >).

FIG. 7 is a diagram showing a treatment effect on particles when the organic acid treatment solution, organic alkaline treatment solution and pure water according to the present invention are used alone.

FIG. 8 is a cross-sectional view schematically showing a state in which dishing has occurred on a semiconductor wafer as a substrate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate (semiconductor wafer) 2 Substrate cleaning device 3a, 3b Rotary brush 5a Shaft 5b Brush 5c Projection 6a-6e Holding roller 7 Drive roller 8a Roller member 8b Stepped portion 8c Shaft member 9 Cleaning fluid supply nozzle 12 Super Sonic cleaning device 13 Holder (fixing means) 13a Convex part (fixing means) 13b Holding pin (fixing means) 14 Chuck member (fixing means) 15 Shaft member 17 Cleaning fluid ejection nozzle (ultrasonic nozzle) 19 (substrate transfer device) ) Claw portion 23 discharge duct 24a cleaning fluid supply path 24b back surface cleaning fluid ejection port 51 metal wiring 52 barrier film 53 interlayer insulating film 55 dishing 56 step

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C23G 1/02 C23G 1/02 1/14 1/14 H01L 21/306 H01L 21 / 306F (72) Inventor Tadayasu Osawa 3-1-5 Sakae-cho, Hamura-shi, Tokyo F-term in Kaijo Corporation (Reference) 4K053 PA06 PA09 PA10 QA06 QA07 RA07 RA13 RA42 RA44 RA45 RA46 RA47 RA49 RA51 RA52 RA54 RA62 SA02 SA04 SA17 SA18 TA16 TA18 TA19 XA01 XA08 XA09 XA22 XA38 5F043 BB27 DD12 DD16 DD19 EE07 EE08 FF07 GG02

Claims (14)

[Claims] A substrate for performing a chemical mechanical polishing process by supplying a polishing liquid to a substrate having a metal wiring with a metal material exposed on the surface, and processing the substrate after the chemical mechanical polishing process A processing method, wherein an organic alkali that is non-reactive with respect to the metal material and a complexing agent that forms a complex with a metal contained in the polishing liquid and particles of the metal material are treated with an organic alkaline processing liquid. A first step of cleaning the substrate; and after the first step, a complex is formed with an organic acid that is non-reactive with the metal material and a metal contained in the metal material particles and the polishing liquid. A second step of cleaning the substrate with an organic acidic processing solution containing a complexing agent. 2. The substrate processing method according to claim 1, further comprising a third step of cleaning the substrate with an ultrasonic cleaning fluid excited by ultrasonic waves after the second step. 3. The substrate processing method according to claim 2, wherein the ultrasonic cleaning fluid is pure water. 4. The substrate processing method according to claim 2, wherein the third step includes a step of cleaning the substrate with an ultrasonic cleaning fluid and then rotating the substrate at a high speed to dry the substrate. . 5. The substrate processing method according to claim 1, wherein said metal material is copper, tungsten, or aluminum. 6. The substrate processing method according to claim 1, wherein the organic alkali is a quaternary ammonium salt and / or an organic amine. 7. The quaternary ammonium salt is a group consisting of tetramethylammonium hydroxide (TMAH), trimethyl-2-hydroxyethylammonium hydroxide (TMAH), and trimethyl-2-hydroxyethylammonium hydroxide (choline). 7. The method according to claim 6, wherein the compound is at least one compound selected from the group consisting of: 8. The method according to claim 6, wherein the organic amine is at least one compound selected from the group consisting of trimethylamine, triethanolamine, ethylenediamine, guanidine, and toluidine. 9. The complexing agent contained in the organic alkaline treatment liquid is a fluoride ion, an OH group and / or an O ⁻ group having a cyclic skeleton in the molecular structure and bonded to a carbon atom constituting the ring. And at least one substance selected from the group consisting of compounds having at least one.
The substrate processing method according to claim 8. 10. The organic alkaline processing solution contains a second complexing agent having a metal ligand, wherein the second complexing agent is a compound having a donor atom, sulfur or carbon, and a donor atom. The compound having at least one selected from the group consisting of a compound having a nitrogen, a compound having a carboxyl group as a metal coordinating group, and a compound having a carbonyl group as a metal coordinating group. Item 10. The substrate processing method according to any one of items 9 to 10. 11. The organic acid is a carboxylic acid that forms a complex with the oxide particles of the metal material, wherein the carboxylic acid is oxalic acid, citric acid, malic acid, maleic acid, succinic acid, tartaric acid, 11. The compound according to claim 1, wherein the compound is at least one compound selected from the group consisting of malonic acid and salts thereof.
The substrate processing method according to the above. 12. The complexing agent contained in the organic acid treatment solution,
The substrate processing method according to any one of claims 1 to 11, wherein the method is a polyaminocarboxylic acid and / or ammonium fluoride. 13. The polyaminocarboxylic acids are ethylenediaminetetraacetic acid (EDTA), trans-1,2-
Cyclohexanediaminetetraacetic acid (CyDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), N- (2-hydroxyethyl) ethylenediamine-N, N ', N'-triacetic acid (EDTA-O
13. The substrate processing method according to claim 12, wherein the compound is at least one compound selected from the group consisting of H) and salts thereof. 14. A substrate for supplying a polishing liquid to a substrate having a metal wiring in a state where a metal material is exposed on the surface to perform a chemical mechanical polishing process, and processing the substrate after the chemical mechanical polishing process. A processing method, wherein an organic acid non-reactive with the metal material, and an organic acid processing solution containing a complexing agent that forms a complex with a metal contained in the polishing liquid and particles of the metal material. A first step of cleaning the substrate; and after the first step, a complex is formed with the organic alkali that is non-reactive with the metal material and the metal contained in the particles of the metal material and the polishing liquid. A second step of washing the substrate with an organic alkaline processing solution containing a complexing agent.