JP2003257922A - Cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low temperature cleaning method of semiconductor substrate which may be used for wiring at least tungsten or a tungsten alloy and wiring electrode and aluminum or an aluminum alloy, may assure an excel lent deposition cleaning property, and provide an excellent corrosion preventing effect for metal wiring in a semiconductor element and an LCD and for various members such as metal thin film or the like, and to provide a semiconductor substrate cleaning method which can reduce installation space of a cleaning apparatus and the storing space of cleaning liquid. <P>SOLUTION: In this semiconductor substrate cleaning method, a semiconductor substrate is provided with at least (A) wiring or an electrode of tungsten or tungsten alloy, and (B) the wiring of aluminum or an aluminum alloy under temperatures of 15 to 60°C using a composition of a cleaning agent. The cleaning agent contains (a) an acid an/or salt thereof where an acid dissociation index pKa<SB>n</SB>(25°C) of the n-th stage of the n-valent basic acid is 3 or more but 11 or less, (b) water and a (c) chelating agent with nitrogen atoms within the molecule. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a semiconductor substrate including at least a wiring or electrode made of tungsten or a tungsten alloy and a wiring made of aluminum or an aluminum alloy. More specifically, a step of forming a semiconductor element on a semiconductor substrate such as a silicon wafer, in particular, a wiring or electrode of tungsten or a tungsten alloy and a wiring of aluminum or an aluminum alloy were subjected to dry etching and ashing using a reaction gas. The present invention relates to a method for cleaning a semiconductor substrate after ashing used in a step of removing so-called depots such as a residual residue, that is, a resist residue and an etching residue. In particular, it should be used in the depot cleaning process after dry etching and ashing in the manufacturing process (front end process) of tungsten or tungsten alloy wiring or gate electrode, the bit line forming process, the aluminum or aluminum alloy wiring forming process, etc. And a method for cleaning a semiconductor substrate.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices and LCDs,
PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition)
After forming a conductive film or an insulating film by a method such as the above, a step of forming a predetermined resist pattern on the thin film by lithography and selectively etching and removing the lower layer thin film is performed using this as a mask. After that, the resist is removed by ashing (ashing), but the deposit mainly composed of the inorganic compound remains. However, in the conventionally known cleaning method, when removing the depot, the cleaning solution must be changed a plurality of times depending on the type of metal such as tungsten, aluminum, or alloys thereof, and the work efficiency is extremely high. It was bad. In addition, high-temperature cleaning was necessary in order to exert the cleaning performance of the chemicals.

Further, since the clean room used for the cleaning treatment needs to keep the temperature and humidity constant while removing dust and bacteria in the air for 0.5 to 0.1 micron. The larger the area (size), the higher the costs such as construction cost and capital investment cost. Therefore, in recent years, from the viewpoint of cost reduction,
Space saving of the clean room is indispensable, and the cleaning device installed in the clean room is also required to be compact.

[0004]

DISCLOSURE OF THE INVENTION The present invention is excellent in deposit cleaning ability and can be commonly used for at least tungsten or tungsten alloy wiring or electrodes and aluminum or aluminum alloy wiring.
An object of the present invention is to provide a low-temperature cleaning method for a semiconductor substrate, which is excellent in the corrosion prevention effect on various members such as metal wiring and metal thin film on D. Another object of the present invention is to provide a method for cleaning a semiconductor substrate that can reduce the installation space of the cleaning device and the storage space of the cleaning liquid.

[0005]

Means for Solving the Problems The present inventors have made detailed investigations on the deposit cleaning property of wirings and electrodes made of tungsten or a tungsten alloy (hereinafter also referred to as W or W alloy). It was found for the first time that, unlike the case of wiring of Al or Al alloy), the cleaning property of the depot improves as the pH increases. It has also been found that in the case of Al or Al alloy wiring, the depot (aluminum oxide) is dissolved although the amount is higher or lower than the neutral region. further,
In recent years, since the wiring width has become as thin as 0.13 to 0.18 μm, the etching area has become smaller and the deposit has become thinner, so that there is a tendency for it to be easier to clean.
Therefore, by taking these facts into consideration, the present invention showing common cleaning effect on the depot of W or W alloy wiring and electrode, and the depot of Al or Al alloy wiring is studied. It came to completion.

That is, the gist of the present invention is: (a) an acid and / or a salt thereof, in which the acid dissociation index pKa _n (25 ° C.) of the n-th stage basic acid is 3 or more and 11 or less; b) water,
(C) A detergent composition containing a chelating agent containing a nitrogen atom in the molecule and having a pH of 6 or more and 11 or less is used, and at least (A) a wiring or an electrode of tungsten or a tungsten alloy and (B) ) A method for cleaning a semiconductor substrate, which comprises cleaning a semiconductor substrate provided with aluminum or aluminum alloy wiring at 15 to 60 ° C.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the cleaning method of the present invention comprises: (a) the acid dissociation index pKa of the n-th basic acid in the nth stage.
an acid and / or salt thereof having an _n (25 ° C.) of 3 or more and 11 or less, (b) water, and (c) a chelating agent containing a nitrogen atom in the molecule, and having a pH of 6 or more and 11 or less. There is one major feature in using a certain cleaning composition.

By using such a cleaning method for cleaning a semiconductor substrate, at least (A) wiring or electrode of tungsten or a tungsten alloy (hereinafter also referred to as W or W alloy) and (B) aluminum or an aluminum alloy (hereinafter , Al or Al alloy) wiring is effectively removed while suppressing corrosion of various components such as semiconductor elements and metal wiring on the LCD and metal thin films.

The cleaning method of the present invention is to clean a semiconductor substrate having at least W or W alloy wiring or electrodes and Al or Al alloy wiring using the above cleaning composition. Specific examples of such a cleaning method include dipping, submerged shower, and air shower.

As the dipping method, one wafer to be processed is used.
Examples include a method of setting one by one or a plurality of sheets collectively in a jig, immersing the jig in the cleaning composition, and shaking the jig or applying a mechanical force such as ultrasonic waves to the cleaning liquid to perform a cleaning treatment. Examples of the in-liquid shower method include a method of performing a cleaning process while applying a jet flow to a wafer to be processed in the liquid of the cleaning composition. Also, as an air shower method,
A method of spraying (showing) the cleaning composition onto a wafer to be processed in air and performing cleaning processing can be mentioned. As a cleaning device used in these cleaning methods, a commonly known device can be used.

Further, the cleaning method of the present invention is also characterized in that the cleaning temperature is low, and the cleaning temperature is 15 to 60 ° C. from the viewpoint of preventing the corrosion of the metal wiring, which is a good cleaning. From the viewpoint of achieving both goodness and reduction of utility cost, 20 to 50 ° C is preferable, and 25 to 50 ° C is particularly preferable.
40 ° C. is preferred.

The washing time is preferably 1 to 30 minutes, more preferably 5 to 20 minutes, particularly preferably 5 to 15 minutes.

The cleaning method and conditions can be changed according to the type of the cleaning product.

After these cleaning steps, it is preferable to remove the cleaning composition remaining on the wafer by rinsing with water or a solvent such as isopropyl alcohol.

By using the cleaning method of the present invention as described above, it is possible to easily clean the deposit attached to the member such as a semiconductor element or an inorganic member such as LCD without damaging the member.

In the present invention, "(A) wiring or electrode of at least W or W alloy and (B) Al or Al"
The term “semiconductor substrate including alloy wiring” means that the semiconductor substrate to be cleaned includes at least (A) wiring or electrode having W or W alloy and (B) wiring having Al or Al alloy. Further, the semiconductor substrate may further include another metal member such as copper or a copper alloy.

Therefore, the cleaning method of the present invention comprises a step of forming a semiconductor element on a semiconductor substrate such as a silicon wafer,
Among them, a step of removing a so-called depot such as a residue after dry etching and ashing of a wiring or an electrode having W or a W alloy and Al or an Al alloy using a reaction gas, that is, a resist residue and an etching residue, in particular, W
Alternatively, it is preferably used for a gate electrode forming step (front end process) having a W alloy, a bit line forming step, a wiring forming step having an Al or Al alloy, and a depot cleaning step after dry etching and ashing.

In particular, in a semiconductor manufacturing process, a W or W alloy wiring, a W or W alloy electrode, and an Al or Al alloy wiring are manufactured by appropriately dividing the steps in a desired order. Therefore, the cleaning method of the present invention can be applied to semiconductor devices and LCDs.
Since depots adhered to members such as inorganic members can be easily washed without damaging those members, they can be suitably used for a plurality of depot washing steps in the manufacturing process of semiconductor devices, LCDs and the like.

Further, the cleaning method of the present invention as described above,
By using it in a plurality of depot cleaning steps in the semiconductor manufacturing process, an excellent effect that the installation space of the cleaning device and the storage space of the cleaning liquid can be significantly reduced is exhibited.

The cleaning composition used in the present invention is described below.
Will be described. The (a) acid used in the present invention is n
Acid dissociation index pKa of the nth stage of valent basic acid _n(25 ° C)
Is 3 or more and 11 or less. pKa_n(25 ° C)
Is a depot-cleaning and corrosion-resistant material for tungsten and aluminum.
From the viewpoint of compatibility of food quality, 5 or more and 11 or less are preferable. Na
Oh, pKa_n(25 ° C) is obtained by the following method
I mean something.

(Explanation of pKa _n ) When an n-valent acid (represented by H _n A as a general formula) is dissolved in water, it dissociates as follows.

[0022]

[Equation 1]

At this time, the dissociation constants Ka ₁ , Ka ₂ , and Ka _n of the _first , _second , and nth stages are defined as follows. _{Ka 1 = [H n-1} A -] [H +] / [H n A] Ka 2 = [H n-2 A 2-] [H +] / [H n-1 A -] Ka n = [ A ^n- ] [H ⁺ ] / [HA ^(n-1)- ]

Therefore, the logarithm of the reciprocal of Ka _n , that is, the dissociation index of the nth stage is expressed as pKa _n . pKa _n = log (1 / Ka _n ) = − logKa _n

In the present invention, pKa _n is the Chemical Dissertation Revised 4th Edition, Basic Edition II (Edited by The Chemical Society of Japan), page II-317, Tables 10 and 18 Acid dissociation constants of inorganic compounds in aqueous solution (25
), II-317 to 321 pages, Tables 10 and 19 acid dissociation constants of organic compounds (25 ° C), given from the 4th edition of the Physical and Chemical Dictionary (Iwanami Shoten), and those not listed above are ion equilibrium. (Kagaku Dojin), page 53, 66-68.

Examples of the component (a) include oxo acid,
Inorganic acids such as hydrogen acid and peroxo acid; carboxylic acid, thiocarboxylic acid, peracid, mercaptan, sulfonic acid, phosphatidic acid, dithiocarboxylic acid, sulfinic acid, sulfenic acid, phosphonic acid, phosphinic acid, carbonic acid ester, sulfuric acid ester, phosphorus Organic acids such as acid esters and borate esters can be mentioned.

Specific examples of the inorganic acid include carbonic acid, bicarbonate,
Boric acid, iodic acid, nitric acid, sulfuric acid, hypobromic acid, hypochlorous acid, chlorous acid, perchloric acid, oxo acid such as nitrous acid, sulfurous acid; hydrobromic acid, hydrochloric acid, hydrofluoric acid, iodine Hydrous acid,
Examples thereof include hydrogen acids such as hydrosulfuric acid; peroxo acids such as peroxo nitric acid, peroxosulfuric acid, and peroxodisulfuric acid.

Among the organic acids, carboxylic acids are preferable from the viewpoints of depot cleanability and corrosion prevention of metal materials. As the carboxylic acid, a linear saturated monocarboxylic acid,
Linear unsaturated monocarboxylic acid, branched saturated monocarboxylic acid, branched unsaturated monocarboxylic acid, saturated polycarboxylic acid, unsaturated polycarboxylic acid, hydroxycarboxylic acid, alkoxycarboxylic acid, carboxylic acid having an aromatic ring And carboxylic acids having an alicyclic ring.

The carboxylic acid is represented by the formula (II): B-[(R ³ ) _p- (COOH) _q ] _r (II) (wherein R ³ is a hydrogen atom, a straight chain having 1 to 40 carbon atoms). , A saturated or unsaturated hydrocarbon group having a branched or cyclic skeleton, the hydrocarbon group of R ³ may have 1 to 5 oxygen atoms or sulfur atoms, and the carbon atom of R ³ The hydrogen atom bonded to R may be substituted with an -OH group or a -SH group, and q -COOH groups may be bonded to the same carbon atom of R ³ by one or more, p Is 0 or 1, q is an integer of 1 to 40, r is an integer of 1 to 3, B is absent or represents an -O- group, a -CO- group or a -S- group. Acids are preferred.

In the formula (II), the depot cleaning property and the metal material
R from the viewpoint of corrosion prevention for materials ³Is a hydrogen atom, carbon
Linear saturated hydrocarbon group having 1 to 18 carbon atoms, 3 to 18 carbon atoms
Branched-chain saturated hydrocarbon group, straight-chain having 2 to 18 carbon atoms
Unsaturated hydrocarbon group of 3 to 18 carbon atoms in a branched chain
Japanese hydrocarbon group, saturated with alicyclic ring having 3 to 18 carbon atoms or
Saturated unsaturated hydrocarbon group and aromatic ring having 6 to 18 carbon atoms
Sum or unsaturated hydrocarbon groups are preferred. Furthermore, R³Is
Straight-chain saturated hydrocarbon group having 1 to 12 carbon atoms, 3 to 3 carbon atoms
12 branched chain saturated hydrocarbon groups, directly having 2 to 12 carbon atoms
Chain unsaturated hydrocarbon group, branched chain having 3 to 12 carbon atoms
Unsaturated hydrocarbon group, saturated with alicyclic ring having 3 to 12 carbon atoms
Or having an unsaturated hydrocarbon group or an aromatic ring having 6 to 12 carbon atoms
More preferred are saturated or unsaturated hydrocarbon groups. In particular, R
³Is a linear saturated hydrocarbon group having 1 to 6 carbon atoms, and 3 carbon atoms
~ 6 branched saturated hydrocarbon group, straight chain having 2 to 6 carbon atoms
Unsaturated hydrocarbon group, branched chain unsaturated carbon atoms having 3 to 6 carbon atoms
Japanese hydrocarbon group, saturated or unsaturated having an alicyclic ring having 3 to 6 carbon atoms
Saturated hydrocarbon group, saturated or saturated aromatic ring having 6 to 8 carbon atoms
Is most preferably an unsaturated hydrocarbon group. Also, R³Carbonization of
When the hydrogen group has an oxygen atom or a sulfur atom,
1-2 is more preferable.

Further, in the formula (II), q is preferably an integer of 1 to 18, more preferably an integer of 1 to 12, from the viewpoint of depot cleanability and corrosion prevention of metal materials.
An integer of 6 is more preferable, and an integer of 1 to 2 is particularly preferable.

Specific examples of preferred carboxylic acids include straight chain saturated monocarboxylic acids having 1 to 18 carbon atoms such as formic acid, acetic acid and propionic acid; acrylic acid, crotonic acid, vinyl acetic acid, 4-pentenoic acid and 6- Linear unsaturated monocarboxylic acids such as heptenoic acid, 2-octenoic acid, undecylenic acid, oleic acid; isobutyric acid, isovaleric acid, pivalic acid, 2
-Methylbutyric acid, 2-methylvaleric acid, 2,2-dimethylbutyric acid, 2-ethylbutyric acid, tert-butylbutyric acid, 2,2-
Dimethylpentanoic acid, 2-ethylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, 2,4-dimethylhexanoic acid, 2-methylheptanoic acid, 2-propylpentanoic acid, 3,5,5-trimethylhexane Acid, 2-methyloctanoic acid, 2-ethylheptanoic acid, 2-ethyl-
Branched chain saturated monocarboxylic acids such as 2,3,3-trimethylbutyric acid, 2,2,4,4-tetramethylpentanoic acid, 2,2-diisopropylpropionic acid; methacrylic acid, tiglic acid, 3,3-dimethylacryl Branched chain unsaturated monocarboxylic acid such as acid, 2,2-dimethyl-4-pentenoic acid, 2-ethyl-2-hexenoic acid, citronellic acid; oxalic acid, malonic acid, methylmalonic acid, ethylmalonic acid, dimethylmalon Acid, succinic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, glutaric acid, adipic acid, 3-methyladipic acid, sebacic acid, hexadecanedioic acid, 1,
Saturated polycarboxylic acids such as 2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, polyacrylic acid, and polymaleic acid; maleic acid, fumaric acid, citraconic acid, mesaconic acid, cis-aconit Unsaturated polycarboxylic acids such as acids and trans-aconitic acids; hydroxycarboxylic acids such as lactic acid, gluconic acid, tartaric acid, malic acid and citric acid; alkoxycarboxylic acids such as methoxyacetic acid and ethoxyacetic acid; benzoic acid, terephthalic acid, Carboxylic acids having an aromatic ring such as trimellitic acid and naphthoic acid; alicyclic carboxylic acids such as cyclohexanecarboxylic acid, cyclohexanepropionic acid, cyclohexanebutyric acid and cyclopentanecarboxylic acid.

Of these, straight chain saturated monocarboxylic acids having 1 to 6 carbon atoms such as formic acid, acetic acid and propionic acid; saturated polycarboxylic acids such as oxalic acid, malonic acid and succinic acid; lactic acid and gluconic acid. More preferred are hydroxycarboxylic acids such as tartaric acid, malic acid and citric acid; and alkoxycarboxylic acids such as methoxyacetic acid and ethoxyacetic acid. Particularly, formic acid, acetic acid, oxalic acid, malonic acid, succinic acid, lactic acid, gluconic acid, tartaric acid, malic acid and citric acid are preferable.

The molecular weight of the carboxylic acid is not particularly limited, but is preferably 46 to 400, and more preferably 46 from the viewpoint of depot cleanability and corrosion prevention of metal materials.
~ 200.

Examples of such acid salts include salts of acids with basic organic compounds or basic inorganic compounds. Examples of the basic organic compound include primary amines, secondary amines, tertiary amines, imines, alkanolamines, amides, basic heterocyclic compounds and quaternary ammonium hydroxide. Examples of the basic inorganic compound include ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide and the like. Among these, ammonium salts of acids and salts of acids with basic organic compounds are preferable from the viewpoint of avoiding contamination with metal ions. In particular, the ammonium salt is particularly preferable because the deposit formed in the W or W alloy wiring or electrode is tungsten oxide, so that the ammonium salt becomes water-soluble by forming the ammonium salt of tungsten and easily peels off. These acid salts can be used alone or
You may use it in mixture of 2 or more types.

The acids and / or salts thereof may be used alone or in admixture of two or more.

The content of the (a) acid and / or its salt in the detergent composition is preferably 0.01 to 65% by weight from the viewpoint of obtaining excellent depot cleaning properties. From the viewpoint of preventing corrosion against
55 wt% is more preferable, 0.1 to 35 wt% is more preferable, and 0.5 to 20 wt% is particularly preferable.

The water (b) used in the present invention is ionic such as ion-exchanged water, pure water or ultrapure water in view of the fact that the detergent composition is used in the field of manufacturing semiconductor devices and LCDs. It is preferable to reduce substances and particles as much as possible.

(B) The content of water in the detergent composition is from 30 to 99% by weight from the viewpoint of improving the depot detergency.
Is preferred. In the present invention, by adjusting the content of water in such a range, it is possible to obtain a detergent composition having excellent depot cleaning properties and an effect of preventing corrosion of metal materials. Further, the content of water is more preferably 40 to 40 from the viewpoints of depot cleanability and prevention of corrosion of metal materials.
It is 97% by weight, more preferably 60 to 95% by weight.

The chelating agent (c) containing a nitrogen atom in the molecule refers to a compound having a primary to tertiary amino group and / or quaternary ammonium salt in the molecule and a molecular weight of 40 to 3000. The chelating agent refers to a sequestering agent that produces a water-soluble metal chelate, and specifically refers to a multidentate ligand that coordinates with a metal ion and wraps the metal ion.
An electron donor having the ability to coordinate with a metal ion is called a ligand, and one molecule of the ligand has two electron donor groups,
Those having three or four are called bidentate, tridentate, and tetradentate ligands, respectively, and bidentate or higher ligands are collectively called a multidentate ligand.
(C) An example of a chelating agent containing a nitrogen atom in the molecule is “Stability constant table of“ Metal chelate (III) ”(edited by Keihei Ueno, Takeichi Sakaguchi, published by Nankodo, 1st edition of 1942). One or more selected from the group consisting of amines and their derivatives, aminopolycarboxylic acids and amino acids described on pages 15-55.

The amine and its derivative have the formula: R^FourR^FiveR⁶N (In the formula, R^Four, R^FiveAnd R⁶Is a hydrogen atom and has 1 to 2 carbon atoms
Saturation consisting of 0 straight chain, branched chain or cyclic skeleton
Or an unsaturated hydrocarbon group, R^Four, R^FiveAnd R ⁶Charcoal
Hydrogen fluoride group is 1 to 5 oxygen atoms, nitrogen atoms or sulfur atoms
May have R^Four, R^FiveAnd R⁶On the carbon atom of
The bonded hydrogen atom is -OH group, -NH ₂Group or -S
H₂It may be substituted with a group. In addition, R^Four, R^Fiveas well as
R⁶May be the same or different. )
The compound represented by

Specific examples thereof include ethylenediamine,
N-methylethylenediamine, N-ethylethylenediamine, N- (2-hydroxyethyl) ethylenediamine, trimethylenediamine, tetramethylenediamine,
Examples include pentamethylenediamine, triethylenediamine, imidazole, histamine and the like.

The aminopolycarboxylic acid has the formula: R^FourNY₂, NY₃, R^FourYN-CH₂CH₂-NYR
^Five, R^FourYN-CH₂CH₂-NY₂, Y₂N- (CH
₂)_u-NY₂ (In the formula, R^FourAnd R^FiveIs the same as above, Y is -CH₂CO
OH or -CH₂-CH ₂Indicates COOH. u is 1 to 1
Indicates an integer of 0. ).

Specific examples thereof include R ⁴ NY ₂ type iminodiacetic acid and hydroxyethyliminodiacetic acid; NY ₃
A type nitrilotriacetic _{^{acid; R 4 YN-CH 2 CH}} 2 -
NYR ⁵ type N, N′-ethylenediamine diacetic acid;
R ⁴ is a YN-CH ₂ CH ₂ -NY ₂ type N'- hydroxyethyl -N, N, N'- triacetic acid; Y ₂ N- (CH
₂ ) _u- NY ₂ type ethylenediaminetetraacetic acid and the like can be mentioned. Among them, N, N'-ethylenediaminediacetic acid, N'-hydroxyethyl-N, N, N'-, from the viewpoint of depot cleanability of wiring or electrodes having W or W alloy.
Triacetic acid and ethylenediaminetetraacetic acid are preferred.

An amino acid has a carboxyl group (C
It should have OOH) and an amino group (NH ₂ ). Specific examples thereof include glycine, alanine, β-alanine, sarcosine, aspartic acid, asparagine, lysine, serine, and dihydroxyethylglycine (N, N-
Bis (2-hydroxyethyl) glycine), glycine N, N'-1,2-ethanedylbis [N- (carboxymethyl), glycine N- [2- [bis (carboxymethyl) amino] ethyl] -N- (2 -Hydroxyethyl)
Glycine derivatives and the like. From the viewpoint of depot cleaning of W or W alloy wiring or electrodes, glycine, alanine, aspartic acid, N, N-bis (2-hydroxyethyl) glycine, glycine N, N′-1,2-ethanedylbis [N- (Carboxymethyl) and glycine N-
[2- [bis (carboxymethyl) amino] ethyl]-
N- (2-hydroxyethyl) is preferred.

The content of the compound having a nitrogen atom in the molecule (c) in the detergent composition is 0.01 to 2
0% by weight is preferable, 0.05 to 10% by weight is more preferable, and 0.1 to 5% by weight is further preferable. The content is
From the viewpoint of depot cleaning of W or W alloy wiring or electrodes,
It is preferably 0.01% by weight or more, and from the viewpoint of compatibility, it is preferably 20% by weight or less.

The detergent composition may contain (d) an organic solvent. (D) The organic solvent may be represented by the formula (I): R ¹ [(X) (AO) _k R ² ] _m (I) (wherein R ¹ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, X is an -O- group, a -COO- group, a -NH- group, or-
N ((AO) _n H) -group, k and n are 1 to 20, A is an alkylene group having 2 or 3 carbon atoms, R ² is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and m is 1 8 is shown. ), Alkylene oxide compounds, alcohols, ethers, carbonyls, esters, phenols, nitrogen-containing compounds, sulfur-containing compounds and the like. (D) Specific examples of the organic solvent are the data edition 331 to 76 of New Edition Solvent Pocket Book (Ohm Co., Ltd., issued June 10, 1994).
The compounds described on page 1 can be mentioned.

In the formula (I), R ¹ is preferably a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, R ² is preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and a hydrogen atom or a carbon atom. The hydrocarbon group of the number 1 or 2 is more preferable, and m is 1
3 are preferable, and 1 or 2 is more preferable.

Specific examples of the alkylene oxide compound represented by the formula (I) include methyl ether, ethyl ether, propyl ether, butyl ether, hexyl ether, phenyl ether, benzyl ether, dimethyl ether and diethyl ether of ethylene glycol.
Butyl methyl ether, ethyl propyl ether, butyl ethyl ether, dipropyl ether, dibutyl ether, etc .; diethylene glycol alkyl ether, triethylene glycol alkyl ether, etc. corresponding to them; tetraethylene glycol methyl ether, ethyl ether, propyl ether, butyl ether, Hexyl ether, phenyl ether, benzyl ether,
Dimethyl ether, diethyl ether and the like; and corresponding pentaethylene glycol alkyl ether, hexaethylene glycol alkyl ether, propylene glycol alkyl ether, dipropylene glycol alkyl ether, tripropylene glycol alkyl ether and the like.

Alcohols used in the present invention are represented by the formula (III): R ^3- (OH) _m (III) (wherein R ³ and m are defined in the formula (II) and the formula (I). And the same as) respectively.

Examples of the ethers include compounds represented by the formula (IV): R ³ —O—R ³ (IV) (wherein R ³ is the same as the definition of the formula (II)).

The carbonyls are represented by the formula (V):

[0053]

[Chemical 1]

(Wherein R ³ is the same as the definition of the above formula (II)).

Examples of the esters include compounds represented by the formula (VI): R ³ —COOR ³ (VI) (wherein R ³ is the same as the definition of the formula (II)).

The phenols have the formula (VII):

[0057]

[Chemical 2]

(In the formula, R ⁷ is a saturated or unsaturated hydrocarbon group having a linear, branched or cyclic skeleton having 1 to 9 carbon atoms, and the hydrocarbon group of R ⁷ is 1 to 5 May have an oxygen atom, a nitrogen atom or a sulfur atom, and the hydrogen atom bonded to the carbon atom of R ⁷ is —OH group, —NH ₂
It may be substituted with a group, —SH group or —NO ₂ group.
s shows 0-5, t shows 1-3. ) Refers to a compound represented by.

The nitrogen-containing compound is not particularly limited as long as it is a compound containing a nitrogen atom having a molecular weight of 200 or less. The sulfur-containing compound is not particularly limited as long as it is a compound containing a sulfur atom having a molecular weight of 200 or less.

The organic solvent (d) is, from the viewpoint of permeability, diethylene glycol monobutyl ether and diethylene glycol monohexyl ether which are alkylene oxide compounds represented by the formula (I); propanols, butanol and pentanol which are alcohols; ethers. Trioxane and methylal which are carbonyls; acrolein and methyl ethyl ketone which are carbonyls; acetoacetic nitrile and ethyl formate which are esters; benzylphenol which is a phenol; dimethylformamide, dimethylacetamide and N-methyl-2- which are nitrogen-containing compounds Pyrrolidone and dimethylimidazolidinone; sulfur-containing compounds dimethyl sulfoxide and sulfolane are preferred. These (d) organic solvents may be used alone or in 2
You may use it in mixture of 2 or more types.

Further, the melting point of the organic solvent (d) is preferably 60 ° C. or lower from the viewpoints of ensuring depot cleaning properties and workability.
30 ° C. or lower is more preferable, and 10 ° C. or lower is further preferable.

The organic solvent (d) is used in an amount of 0.5% by weight or more in water at 25 ° C. from the viewpoint of accelerating the permeation of the acid and / or its salt or water into the depot and consequently improving the depot cleaning property. It is preferably soluble, more preferably 4% by weight or more, even more preferably 7% by weight or more.

The content of the organic solvent (d) in the detergent composition is preferably 0.1 to 90% by weight, and preferably 0.5 to 80% by weight, from the viewpoint of obtaining excellent depot cleaning properties and high penetrating power. Is more preferable, and 1 to 50% by weight is further preferable.

In the cleaning composition (a) to
The content of the component (d) may be either the content at the time of producing the composition or the content at the time of use. Usually, the composition is produced as a concentrated solution, and it is often used by diluting the composition.

PH of detergent composition containing the above components
Is required to be 6 or more and 11 or less. In the present invention, there is one great feature that the pH of the detergent composition is 6 or more and 11 or less.
By adjusting the amount as described below, it is possible to obtain an excellent effect that the deposit cleaning property is sufficient and the corrosion of the metal material can be suppressed, and as a result, the productivity and quality of the semiconductor element can be improved. Therefore, even if the cleaning composition contains the components (a) to (c) or further the component (d), if the pH is less than 6, excellent depot cleaning of W or W alloy wiring or electrodes is achieved. And corrosion resistance to metal materials cannot be obtained. The lower limit of the pH is preferably 6.5 or higher, more preferably 7.0 or higher, even more preferably 7.5 or higher, and particularly preferably 8.0 or higher. The upper limit of pH is preferably 10 or less, more preferably 9.5 or less,
9.2 or less is more preferable, and 8.7 or less is particularly preferable. The pH is preferably 6.5 to 10, more preferably 7.0 to 9.5, and further preferably 7.5 to 9.
2, particularly preferably 8.0 to 9.2, and most preferably 8.0 to 8.7.

Further, as an optional component, a surfactant such as a nonionic surfactant or an anionic surfactant can be appropriately blended.

[0067]

EXAMPLES Examples 1 to 15 and Comparative Examples 1 to 5 (Evaluation of cleaning characteristics) Tungsten (W) wiring pattern 700 μm thick Si / SiO ₂ / poly Si / WN / W /
Si ₃ N ₄ [Substrate / 3/100/10/50/50 (n
m)] was patterned using a positive photoresist made of a novolac resin material and plasma-etched. Fluorine-based gas and chlorine-based gas were sequentially used as the etching gas. After etching, the photoresist was removed by oxygen plasma ashing.

An aluminum (Al) wiring pattern 700 μm thick Si / Ti / TiN / Al / TiN [substrate / 100/100/400/100 (nm)] laminated substrate is coated with a positive photoresist of a novolac resin material. It was patterned and used for plasma etching treatment. A chlorine-based gas and a fluorine-based gas were sequentially used as the etching gas. After etching, the photoresist was removed by oxygen plasma ashing.

Hole pattern on copper (Cu) wiring 700 μm thick Si / Cu / Si ₃ N ₄ / SiO ₂ [substrate / 400/50/300 (nm)] laminated substrate positive type of novolac resin material Patterning was performed using a photoresist and plasma etching treatment was performed. A chlorine-based gas and a fluorine-based gas were sequentially used as the etching gas. After etching, the photoresist was removed by oxygen plasma ashing.

Substrates were cleaned using the cleaning compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 5 shown in Tables 1 and 2. In Examples 1 to 9 and 11 and Comparative Examples 1 to 5, cleaning was performed by immersing the substrate in the cleaning composition at 30 ° C for 10 minutes. In Example 10, the cleaning composition was sprayed on the substrate to be treated at 30 ° C. for 5 minutes in the air for cleaning. In Examples 12 and 13, cleaning was performed by immersing the substrate in the cleaning composition at 60 ° C. and 50 ° C. for 10 minutes, respectively.
In Examples 14 and 15, cleaning was performed by immersing the substrate in the cleaning composition at 30 ° C. for 10 minutes. After washing, the substrate was rinsed with water. After drying, the surface of the substrate was magnified 50,000 times with a field emission scanning electron microscope, and 100 formed wirings or hole patterns were observed, and the deposit cleaning property and the wiring corrosiveness were evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[Depot Cleaning Property] Depot cleaning ratio = (number of patterns from which deposits have been completely removed) / 100 Evaluation criteria A: 95% or more and 100% or less, B: 90% or more and less than 95%, C: 80% or more and less than 90%, D: 0% or more and less than 80%

[Corrosion of wiring] Corrosion rate = (number of resist patterns in which stains or pitting corrosion is recognized) / 100) × 100 Evaluation criteria A: 0% or more and less than 2.5%, B: 2.5% Or more and less than 5%, C: 5% or more and less than 10%, D: 10% or more and 100%
Hereinafter, in the above evaluation, all the evaluations of A or B are regarded as acceptable products.

[0073]

[Table 1]

[0074]

[Table 2]

From the results of Tables 1 and 2, the detergent compositions obtained in Examples 1 to 15 are present in various wirings as compared with the detergent compositions obtained in Comparative Examples 1 to 5. It can be seen that the depot has excellent cleaning properties and is less likely to corrode.

Example 16 An element isolation oxide film, a polycrystalline Si film, an n-type silicon substrate,
A WN film and a W film are sequentially deposited to form a WN / W composite film. Etching and ashing are performed on the WN / W composite film by a normal photoetching process using a resist pattern as a mask, and then the substrate is air showered with the cleaning composition of any of Examples 1 to 15. (3
After that, the etching residue and the ashing residue (hereinafter referred to as a depot) are washed. Then, the wiring is observed using the method described above.

Next, p-type and n-type LDDs are formed by ion implantation.
Regions, after providing p-type and n-type source and drain regions,
An interlayer insulating film and SiO ₂ are laminated on the entire surface, and the surface is flattened by the chemical mechanical polishing (CMP) method. Then
Contact holes are formed to reach the p-type source and domain regions and the n-type source and drain regions, and W is buried to form a W plug.

Next, a TiN film and an Al film are sequentially deposited on the entire surface, and ordinary photoetching is performed using the resist pattern as a mask. After that, the substrate is subjected to an air shower (30 ° C., 5 minutes) using the cleaning composition of any of Examples 1 to 15 to clean etching residues and ashing residues (hereinafter referred to as depots). Then, the wiring is observed using the method described above. At the above two points,
It is observed that the Al wiring and the W electrode on the substrate have very little deposit and no corrosion occurs.

[0079]

EFFECTS OF THE INVENTION By using the cleaning method of the present invention, it is possible to easily and quickly clean a depot that has been deteriorated by high energy treatment, and moreover, for wiring materials such as aluminum, tungsten and alloys thereof. Corrosion can be suppressed. As a result, it can greatly contribute to the improvement of the productivity of semiconductor elements, LCDs and the like. In addition, by using the cleaning method of the present invention in a plurality of depot cleaning steps in the semiconductor manufacturing process, it is possible to significantly reduce the installation space of the cleaning device and the storage space of the cleaning liquid. To be done.

Claims (4)

[Claims] 1. An acid and / or a salt thereof, which comprises (a) an acid dissociation index pKa _n (25 ° C.) at an nth stage of an n-valent basic acid of 3 or more and 11 or less, and (b) water. c) Contains a chelating agent containing a nitrogen atom in the molecule and has a pH of 6 or more 11
A semiconductor substrate having at least (A) a wiring or an electrode of tungsten or a tungsten alloy and (B) a wiring of an aluminum or an aluminum alloy is washed at 15 to 60 ° C. by using the following cleaning composition. Cleaning method. 2. The cleaning method according to claim 1, wherein the cleaning is performed under a temperature condition of 25 to 40 ° C. 3. The cleaning method according to claim 1, wherein the content of the component (a) in the cleaning composition is 0.01 to 65% by weight. 4. The cleaning method according to claim 1, wherein the cleaning of the semiconductor substrate is performed by at least one selected from the group consisting of immersion, a submerged shower and an air shower.