JP5858597B2 - Cleaning agent for tungsten wiring semiconductor - Google Patents

Description

The present invention relates to a cleaning agent (hereinafter referred to as a post-CMP cleaning agent) used in a cleaning step after a chemical mechanical polishing (hereinafter, “chemical mechanical polishing” is abbreviated as CMP) step in a semiconductor manufacturing process. And, more particularly, a post-CMP cleaning agent for a semiconductor having a tungsten or tungsten alloy wiring on its surface.

  Semiconductor elements typified by silicon semiconductors have been miniaturized and highly integrated in response to market needs such as higher performance and smaller size. Along with this, an advanced planarization technique for creating a fine wiring pattern is essential, and a polishing slurry (hereinafter abbreviated as CMP slurry) containing fine particles of alumina or silica on the wafer surface in a semiconductor manufacturing process. A CMP process that uses and polishes is introduced.

However, in this CMP process, abrasive fine particles such as alumina and silica in the CMP slurry (hereinafter, “abrasive fine particles” are abbreviated as abrasive grains), an iron nitrate aqueous solution added to promote polishing, and metal corrosion suppression purposes. The anticorrosive added in (1), the polished tungsten wiring metal, the residue of zinc or magnesium metal used on the side of the tungsten wiring, etc. are likely to remain on the polished wafer. Since these residues adversely affect the electrical characteristics of the semiconductor such as a short circuit between wirings, it is necessary to remove these residues and clean the wafer surface.
Conventionally, as a cleaning method after this CMP process, a method using an ammonia / hydrogen peroxide aqueous solution or a hydrochloric acid / hydrogen peroxide aqueous solution in combination with a dilute hydrofluoric acid aqueous solution is known. However, these methods cannot be applied to the recent wiring forming process which has been miniaturized due to the great corrosion on the wiring metal.

In order to improve this corrosion, a cleaning process using a cleaning agent containing an organic acid such as citric acid and oxalic acid that is less corrosive to metals and a chelating agent such as aminopolycarboxylic acids has been proposed (patent) Reference 1).
According to this method, it is said that abrasive grains and metal residues can be removed without corroding the metal wiring, and in recent years, it has been applied to many CMP processes. The problem of not being enough is becoming apparent.

Japanese Patent Laid-Open No. 10-72594

In view of this, the present invention eliminates the components remaining on the wafer after the CMP process (abrasive grains such as alumina and silica in the CMP slurry, nitric acid added to promote polishing) without corroding metal wiring such as tungsten wiring. Tungsten and tungsten alloy wiring with excellent removability of iron aqueous solution, anticorrosive added for the purpose of inhibiting the corrosion of wiring metal, and zinc and magnesium metal residues used on the side of polished tungsten wiring metal and tungsten wiring It aims at providing the cleaning agent for semiconductors.

  The inventors of the present invention have reached the present invention as a result of studies to achieve the above object. That is, the present invention is a cleaning agent used in a process subsequent to a CMP process in a semiconductor manufacturing process for forming tungsten or tungsten alloy wiring, and includes an organic amine (A), a quaternary ammonium hydroxide (B), A cleaning agent (D) for a semiconductor process, characterized by having a chelating agent (C) and water (W) as essential components and having a pH of 7.0 to 14.0.

The cleaning agent for tungsten and tungsten alloy wiring semiconductor according to the present invention is excellent in the removal of abrasive grains derived from the abrasive, the removal of metal residues on the insulating film, and the corrosion resistance of tungsten wiring.
By using the cleaning agent of the present invention in the process after the CMP process in the semiconductor manufacturing process, a semiconductor substrate or a semiconductor element having excellent contact resistance and no wiring short-circuit can be easily obtained.

  The cleaning agent for tungsten wiring semiconductor of the present invention essentially comprises a total of four components consisting of organic amine (A), quaternary ammonium hydroxide (B), chelating agent (C), and water (W), and has a pH of It is 7.0-14.0.

Examples of the organic amine (A) in the present invention include chain amines and cyclic amines.
Examples of chain amines include chain monoamines and chain polyamines.
Examples of the chain monoamine include a chain alkyl monoamine having 1 to 6 carbon atoms and a chain alkanolamine (A1) having 2 to 6 carbon atoms.
Examples of the chain polyamine (A2) include alkylene diamines having 2 to 5 carbon atoms and polyalkylene polyamines having 2 to 6 carbon atoms.

  Among chain monoamines, the chain alkylamines having 1 to 6 carbon atoms include alkylamines {methylamine, ethylamine, propylamine, isopropylamine, butylamine, hexylamine, etc.}, dialkylamines {dimethylamine, ethylmethylamine , Propylmethylamine, butylmethylamine, diethylamine, propylethylamine and diisopropylamine}, trialkylamine {trimethylamine, ethyldimethylamine, diethylmethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, etc.} .

  Among the chain monoamines, as the chain alkanolamine (A1) having 2 to 6 carbon atoms, monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, diethylaminoethanol, 2-amino-2-methyl-1-propanol N- (aminoethyl) ethanolamine, N, N-dimethyl-2-aminoethanol, 2- (2-aminoethoxy) ethanol and the like.

  Among the chain polyamines (A2), examples of the alkylene diamine having 2 to 5 carbon atoms include ethylene diamine, propylene diamine, trimethylene diamine, tetramethylene diamine and hexamethylene diamine, and an alkyl group substituted with a hydroxyl group. Examples of the diamine having 2-hydroxyethylaminopropylamine and diethanolaminopropylamine.

  Among the chain polyamines (A2), as polyalkylene polyamines having 2 to 6 carbon atoms, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethyleneheptamine, iminobispropylamine, bis (hexamethylene) triamine and penta Ethylenehexamine etc. are mentioned.

  Examples of cyclic amines include aromatic amines and alicyclic amines, specifically C6-20 aromatic amines [aniline, phenylenediamine, tolylenediamine, xylylenediamine, methylenedianiline, diphenyletherdiamine, naphthalene. Diamine, anthracene diamine, etc.]; C4-15 alicyclic amine [isophorone diamine, cyclohexylenediamine, etc.]; C4-15 heterocyclic amine [piperazine, N-aminoethylpiperazine, 1,4-diaminoethylpiperazine, etc. ] Etc. are mentioned.

  Among these organic amines (A), from the viewpoint of tungsten corrosion resistance and abrasive grain removability, the alkanolamine (A1) represented by the following general formula (1) or the following general formula (2) is preferred. The chain polyamine (A2) is more preferably a chain polyamine from the viewpoint of metal residue removability, and particularly preferably tetraethylenepentamine.

[In Formula (1), R ^{1 to} R ³ each independently represent a hydrogen atom or an alkyl group which may be partially substituted with a hydroxyl group. However, at least one of R ^{1 to} R ³ represents an alkyl group substituted with a hydroxyl group. ]

[In formula (2), R ^{4 to} R ⁸ each independently represents a hydrogen atom or an alkyl group which may be partially substituted with a hydroxyl group. Y ¹ and Y ² each independently represent an alkylene group. n shows 0 or the integer of 1-2. ]

  From the viewpoint of metal removability and tungsten corrosion resistance, the content of the organic amine (A) in use in the cleaning step after the CMP step in the semiconductor manufacturing step for forming the tungsten wiring is organic amine (A), fourth 0.01 to 0.3% by weight, preferably 0.03 to 0.25% by weight, more preferably based on the total weight of secondary ammonium hydroxide (B), chelating agent (C) and water (W) Is 0.05 to 0.2% by weight, particularly preferably 0.07 to 0.15% by weight.

The quaternary ammonium hydroxide (B) that is an essential component of the semiconductor process cleaning agent (D) of the present invention includes a tetraalkylammonium salt, a trialkylhydroxyalkylammonium salt, a dialkyl-bis (hydroxyalkyl) ammonium salt, and And tris (hydroxyalkyl) alkylammonium salt.

  Of these quaternary ammonium hydroxides (B), quaternary ammonium hydroxides (B1) represented by the following general formula (3) are preferred from the viewpoint of abrasive removal.

[In Formula (3), R < ⁹ > -R < ¹² > shows the C1-C3 alkyl group in which one part may be substituted by the hydroxyl group each independently. ]

  Specific examples include tetraalkylammonium hydroxide, (hydroxyalkyl) trialkylammonium hydroxide, bis (hydroxyalkyl) dialkylammonium hydroxide, and tris (hydroxyalkyl) alkylammonium hydroxide.

  Furthermore, from the viewpoint of tungsten corrosion resistance, tetraalkylammonium hydroxide and (hydroxyalkyl) trialkylammonium hydroxide are preferable, and tetramethylammonium hydroxide, tetraethylammonium hydroxide, (hydroxyethyl) trimethylammonium hydroxide are more preferable. (Choline) is preferred, and tetramethylammonium hydroxide is particularly preferred.

  The content of the quaternary ammonium hydroxide (B) when used in the cleaning process after the CMP process in the semiconductor manufacturing process for forming the tungsten wiring is an organic amine (from the viewpoint of abrasive removability and tungsten corrosion resistance). Based on the total weight of A), quaternary ammonium hydroxide (B), chelating agent (C) and water (W), it is usually 0.005 to 10% by weight, preferably 0.01 to 2% by weight. More preferably, it is 0.02 to 1% by weight.

In addition, the molar ratio (B) / (A) of the organic amine (A) to the quaternary ammonium hydroxide (B) is 0.1 to 5.0 from the viewpoint of metal residue removability and abrasive grain removability. Preferably, it is 0.5-2.0.

  As the chelating agent (C), which is an essential component of the semiconductor process cleaning agent (D) of the present invention, a known chelating agent can be used, including a phosphorus chelating agent (C1), an amine chelating agent (C2), and an aminocarboxylic acid. Examples include acid chelating agents (C3), carboxylic acid chelating agents (C4), ketone chelating agents (C5), and polymer chelating agents (C6).

Examples of the phosphorus chelating agent (C1) include sodium pyrophosphate, sodium tripolyphosphate, potassium trimetaphosphate, sodium tetrametaphosphate, 1-hydroxyethylidene-1,1-diphosphonic acid and the like.
Examples of the amine chelating agent (C2) include ethylenediamine, triethylenetetramine, tetraethylenepentamine, dimethylglyoxime, 8-oxyquinoline, porphyrin and the like.
Examples of the aminocarboxylic acid chelating agent (C3) include ethylenediaminediacetic acid and its metal salts (metals such as sodium and potassium) neutralized, ethylenediaminetetraacetic acid and its metal salt neutralized, hexylenediaminediacetic acid and its Neutralized metal salt, hydroxyethyliminodiacetic acid and its metal salt neutralized, nitrilotriacetic acid trisodium, hydroxyethylethylenediaminetriacetic acid trisodium, diethylenetriaminepentaacetic acid pentasodium, triethylenetotolamine hexaacetic acid hexasodium, dihydroxyethyl Examples thereof include glycine, glycine, and tetrasodium L-glutamate diacetate.
Examples of the carboxylic acid chelating agent (C4) include oxalic acid, disodium maleate, ethylene dicarboxylic acid, adipic acid, sebacic acid, gluconic acid, sodium gluconate and the like.
Examples of the ketone chelating agent (C5) include acetylacetone, hexane-2,4-dione, and 3-ethylnonane-4,7-dione.
Examples of the polymer chelating agent (C6) include sodium polyacrylate and poly [sodium 2-hydroxyacrylate].

  Of these chelating agents (C), from the viewpoint of metal residue removability, an amine chelating agent (C2), an aminocarboxylic acid chelating agent (C3), and a carboxylic acid chelating agent (C4) are preferred. Preferred is an aminocarboxylic acid chelating agent (C3), and among the aminocarboxylic acid chelating agents (C3), ethylenediaminetetraacetic acid, hexylenediaminediacetic acid, and hydroxyethyliminodiacetic acid are particularly preferred. .

  The content of the chelating agent (C) at the time of use in the cleaning step after the CMP step in the semiconductor manufacturing process for forming the tungsten wiring is the organic amine (A), the second, from the viewpoint of tungsten corrosion resistance and metal residue removability. Based on the total weight of the quaternary ammonium hydroxide (B), chelating agent (C) and water (W), it is 0.0001 to 0.2% by weight, preferably 0.0005 to 0.1% by weight. Particularly preferred is 0.001 to 0.05% by weight.

The molar ratio (C) / (A) of the organic amine (A) and the chelating agent (C) is preferably 0.001 to 5 from the viewpoint of tungsten corrosion resistance and metal residue removability. Preferably it is 0.003-3, Most preferably, it is 0.005-1.

In the cleaning agent for tungsten wiring semiconductor of the present invention, water (W) is an essential component, and specific examples include those having a low electrical conductivity (μS / cm; 25 ° C.). Specifically, the electrical conductivity is usually 0.055 to 0.05 from the viewpoint of metal residue removability, availability, and prevention of recontamination of tungsten wiring (reattachment of metal ions in water to tungsten wiring). It is 0.2, preferably 0.056 to 0.1, and more preferably 0.057 to 0.08. As such water with low electrical conductivity, ultrapure water is preferable.
In addition, electrical conductivity is measured based on JIS K0400-13-10: 1999.

  The pH of the cleaning agent for semiconductor process (D) in the present invention at 25 ° C. is 7.0 to 14.0, and 10.0 to 13.5 is from the viewpoint of abrasive removability and tungsten corrosion resistance. Preferably, it is 12.0-13.0.

  In the present invention, the pH of the semiconductor process cleaning agent (D) is measured at 25 ° C. using a commercially available pH meter in accordance with JIS Z8802-1984 without dilution.

  In addition to the organic amine (A), quaternary ammonium hydroxide (B), chelating agent (C), and water (W), which are essential components, the cleaning agent for tungsten wiring semiconductor of the present invention includes other components as necessary. As the component (E), a surfactant (E1), a reducing agent (E2) and the like may be added.

Surfactant (E1) can be added from the viewpoint of improving metal residue removability and abrasive grain removability.
Examples of such surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.
In the case of adding a surfactant, the content of the surfactant may be an amount necessary to reduce the surface tension of the cleaning agent, and is usually 0.00 on the basis of the weight of the cleaning agent for tungsten wiring semiconductor of the present invention. It is 0001 to 1% by weight, preferably 0.001 to 0.1% by weight, particularly preferably 0.001 to 0.01% by weight.

Examples of the reducing agent (E2) include organic reducing agents and inorganic reducing agents. Examples of organic reducing agents include catechol, hydroquinone, polyphenolic reducing agents such as gallic acid, oxalic acid or salts thereof, C6-9 aldehydes, etc., and inorganic reducing agents include sulfurous acid or salts thereof, thiosulfuric acid or salts thereof. Examples include salts.

Among these reducing agents, an organic reducing agent is preferable from the viewpoint of tungsten corrosion resistance, more preferably a polyphenol-based reducing agent, and particularly preferably gallic acid.

When these reducing agents are added, the content of the reducing agent is usually 0.0001 to 1.0 weight based on the weight of the cleaning agent for tungsten wiring semiconductor of the present invention from the viewpoint of improving the corrosion resistance of tungsten. %, More preferably 0.001 to 0.5% by weight, particularly preferably 0.01 to 0.1% by weight. If the content of the reducing agent is more than 1.0% by weight, the corrosion resistance of tungsten is lowered.

The tungsten wiring semiconductor cleaning agent of the present invention is prepared by mixing an organic amine (A), a quaternary ammonium hydroxide (B), a chelating agent (C), and, if necessary, other components (E) with water (W). Can be manufactured by.
The mixing method is not particularly limited, but from the viewpoint of easy and uniform mixing in a short time, water (W), organic amine (A), quaternary ammonium hydroxide (B) are mixed, Subsequently, a method of mixing the chelating agent (C) and, if necessary, other components (E) is preferable.
As the mixing device, a stirrer or a disperser can be used. Examples of the stirrer include a mechanical stirrer and a magnetic stirrer. Examples of the disperser include a homogenizer, an ultrasonic disperser, a ball mill, and a bead mill.

  The cleaning agent for tungsten wiring semiconductor according to the present invention is not limited to a semiconductor substrate or semiconductor element having tungsten or tungsten alloy wiring, but also a metal different from tungsten, for example, a semiconductor substrate or semiconductor element having copper wiring, or a recording medium magnetic disk. It can be used for cleaning methods for cleaning aluminum substrates, glassy carbon substrates, glass substrates, ceramic substrates, etc., glass substrates for liquid crystals, glass substrates for solar cells, and the like.

  As a cleaning method for cleaning a semiconductor substrate or a semiconductor element having a tungsten wiring, there are a single wafer method and a batch method. The single wafer method is a method in which a semiconductor substrate or a semiconductor element is rotated one by one and cleaned using a brush while injecting a tungsten wiring semiconductor cleaning agent. The batch method is a plurality of semiconductor substrates or semiconductor elements. Is soaked in a tungsten wiring semiconductor cleaning agent.

  The cleaning agent for tungsten wiring semiconductor of the present invention is a process for producing a semiconductor substrate or semiconductor element having tungsten or tungsten alloy wiring, after resist development, after dry etching, after wet etching, after dry ashing, after resist stripping, and CMP. It can be used for cleaning processes before and after processing and before and after CVD processing. In particular, from the viewpoint of metal residue removability and abrasive grain removability, it is preferably used for the cleaning step after the CMP step.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

Below, preparation of the cleaning agent for tungsten wiring semiconductor of Examples 1-5 and Comparative Examples 1-4 is demonstrated.

Example 1
In a polyethylene 300 ml container, 0.14 part of tetraethylenepentamine (A-1) (trade name: AFR-AN6, purity 99.2%, manufactured by Tosoh Corporation), 25% tetramethylammonium hydroxide aqueous solution (B- 1) (trade name: 25% tetramethylammonium hydroxide solution, 25% purity aqueous solution, manufactured by Tama Chemical Co., Ltd.) 0.240 parts, ethylenediaminetetraacetic acid (C-1) (trade name: Kirest 3A, purity 98.0% After the addition of 0.002 parts (made by Kyrest Co., Ltd.), 99.8 parts of water (W) was added so that the total weight would be 100 parts. The mixture was stirred with a magnetic stirrer to obtain a tungsten wiring semiconductor cleaning agent (D-1) of the present invention. The pH of the obtained cleaning agent was 13.2.

Example 2
In Example 1, in place of (A-1), 0.14 part of monoethanolamine (A-2) (purity 99%, manufactured by Wako Pure Chemical Industries, Ltd.) was used, and the blending amount of (B-1) was set to 0. The procedure was the same as in Example 1 except that the amount was changed to 200 parts, the amount of (C-1) was changed to 0.004 parts, and water was added so that the total weight was 100 parts. The tungsten wiring semiconductor cleaning agent (D-2) was obtained. The pH of the obtained cleaning agent was 12.5.

Example 3
In Example 1, instead of (B-1), a 25% tetraethylammonium hydroxide aqueous solution (B-2) (trade name: 25% tetraethylammonium hydroxide solution, 25% purity aqueous solution, manufactured by Wako Pure Chemical Industries, Ltd.) is used. Except for the above, the same operation as in Example 1 was performed to obtain a tungsten wiring semiconductor cleaning agent (D-3) of the present invention. The pH of the obtained cleaning agent was 12.4.

Example 4
Example 1 Example 1 except that hydroxyethylethylenediaminetriacetic acid (C-2) (purity 98.0%, manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of (C-1) and the amount was 0.004 part. The cleaning operation for tungsten wiring semiconductors (D-4) of the present invention was obtained by performing the same operation as above. The pH of the obtained cleaning agent was 12.9.

Example 5
In Example 4, the blending amount of (A-1) was changed to 0.07 parts, the blending amount of (B-1) was changed to 0.08 parts, and the blending amount of (C-1) was changed to 0.006 parts. Except that water was added so that the total weight became 100 parts, the same operation as in Example 1 was performed to obtain a tungsten wiring semiconductor cleaning agent (D-5) of the present invention. The pH of the obtained cleaning agent was 9.2.

Comparative Example 1
In Example 1, except that (A-1) was not blended, the same operation as in Example 1 was performed to obtain a tungsten wiring semiconductor cleaning agent (D′-1) for comparison. The pH of the obtained cleaning agent was 10.4.

Comparative Example 2
In Example 1, except for not blending (B-1), the same operation as in Example 1 was performed to obtain a tungsten wiring semiconductor cleaning agent (D′-2) for comparison. The pH of the obtained cleaning agent was 9.1.

Comparative Example 3
In Example 1, except having not mixed (C-1), operation similar to Example 1 was performed and the cleaning agent for tungsten wiring semiconductors (D'-3) for a comparison was obtained. The pH of the obtained cleaning agent was 13.4.

Comparative Example 4
After adding 0.100 part of ethylenediaminetetraacetic acid (C-1) and 5.00 parts of oxalic acid (purity 99%, Wako Pure Chemical Industries), water was added so that the total weight would be 100 parts. The same operation as in Example 1 was performed to obtain a tungsten wiring semiconductor cleaning agent (D′-4) for comparison. The pH of the obtained cleaning agent was 4.5.

Cleaning agents for semiconductors for tungsten wirings (D-1) to (D-5) of the present invention prepared in Examples 1 to 5 and cleaning agents for tungsten wiring semiconductors for comparison prepared in Comparative Examples 1 to 4 ( With respect to D′-1) to (D′-4), tungsten corrosion resistance, metal residue removability, and abrasive grain removability were measured and evaluated by the following methods. The evaluation results are shown in Table 1.

<Tungsten corrosion resistance evaluation method>
Evaluation of tungsten corrosion resistance was performed by immersing a wafer having a tungsten single layer film in a cleaning agent for tungsten wiring semiconductor, and then quantifying the concentration of tungsten eluted from the wafer in the cleaning agent. It was determined that the tungsten corrosion resistance was better as the amount of tungsten eluted per unit area was smaller.
The procedure of the evaluation method is shown below.

(1) Pretreatment of wafer having a tungsten single layer film A wafer having a tungsten single layer film (manufactured by ADVAS Materials Technology, made by depositing tungsten metal with a film thickness of 2 μm on a silicon substrate) is 1.0 cm long × 2 width wide. A section of 0.0 cm was cut, immersed in a 10% aqueous acetic acid solution for 1 minute, and then washed with water.

(2) Elution of tungsten A section of a wafer having a pre-processed tungsten monolayer film was immersed in 10 g of each of the tungsten wiring semiconductor cleaning agent, allowed to stand at 25 ° C. for 3 minutes, and then taken out from the cleaning agent.

(3) Measurement of elution amount of tungsten
5 g of the tungsten wiring semiconductor cleaning agent after the slice of the wafer having the tungsten single layer film was immersed was taken out, and the pH was adjusted to 3.0 with an aqueous nitric acid solution. Thereafter, water was added until the total amount became 10 g to prepare a measurement solution.
The concentration of tungsten in the measurement liquid was measured using an ICP-MS analyzer (inductively coupled plasma mass spectrometer) (Agilent Technology, Agilent 7500cs type).

(4) Evaluation and judgment of tungsten corrosion resistance Tungsten elution amount (ng / cm ² ) was calculated by substituting the tungsten concentration into the following formula (1).

W _con : Tungsten concentration in the measurement solution quantified by ICP-MS analysis (ppb (ng / g))
F1: Liquid amount (g) of a cleaning agent for tungsten wiring semiconductor in which a test piece is immersed
F2: Liquid amount (g) of cleaning agent for tungsten wiring semiconductor taken out before pH adjustment
F3: Amount of measurement liquid (g)
S _W : Area of the tungsten single layer film (cm ² ) in the wafer having the single layer film of tungsten

From the calculated tungsten elution amount, tungsten corrosion resistance was determined according to the following criteria. ○: Less than 15 ng / cm ² Δ: 15 ng / cm ^{2 to} 20 ng / cm ²
×: 20 ng / cm ² or more

<Evaluation method of metal residue removability>
Evaluation of metal residue removability is performed by immersing a wafer having a silicon oxide monolayer film in an aqueous solution containing zinc, iron, and magnesium metal ions and then immersing the wafer in a cleaning agent for tungsten wiring semiconductors. The concentration of zinc, iron, and magnesium metal ions eluted from the wafer surface into the cleaning agent is quantified with an ICP-MS analyzer (inductively coupled plasma mass spectrometer; Agilent Technologies, Inc., Agilent 7500cs type). Went by.
It was determined that the metal residue elution amount was superior as the amount of metal ion elution per wafer unit area increased.

(1) Pretreatment of wafer having a silicon oxide single layer film A silicon wafer having a silicon oxide single layer film (manufactured by Advantech, “P-TEOS 1.5 μ”, film thickness of silicon oxide = 1.5 μm) is vertically The sample was cut into sections of 1.0 cm × 2.0 cm wide, immersed in a 10% aqueous acetic acid solution for 1 minute, and then washed with water.

(2) Preparation of aqueous solution containing metal ions To 0.1 part of zinc nitrate, 0.1 part of iron nitrate and 0.1 part of magnesium nitrate, water is added so that the total amount becomes 100 g. An aqueous solution containing 0.1% of each metal ion was prepared.

(3) Contamination treatment of wafer with aqueous metal ion solution
A slice of the wafer having the pretreated silicon oxide single layer film was immersed in 10 g of an aqueous solution containing metal ions for 1 minute, and then dried by nitrogen blowing, thereby attaching metal ions to the surface of the wafer.

(4) Cleaning of wafer A section of a wafer having a silicon oxide single layer film subjected to contamination treatment was immersed in 10 g of a cleaning agent for tungsten wiring semiconductor. After leaving still at 25 degreeC for 3 minutes, it took out from the washing | cleaning agent.

(5) Measurement of the concentration of metal ions eluted from the wafer surface into the cleaning agent
5 g of the tungsten wiring semiconductor cleaning agent after the immersion was taken out, and the pH was adjusted to 3.0 with an aqueous nitric acid solution. Thereafter, water was added until the total amount became 10 g to prepare a measurement solution. The concentrations of zinc, iron, and magnesium metal ions contained in the measurement liquid were measured using an ICP-MS analyzer.

(6) Evaluation judgment of metal residue removability The elution amount of each metal ion was calculated using the following formula.

Metal _con : each metal ion concentration (ppb (ng / g)) in the measurement solution quantified by ICP-MS analysis
G1: Liquid amount (g) of cleaning agent for tungsten wiring semiconductor in which the test piece is immersed
G2: Liquid amount (g) of cleaning agent for tungsten wiring semiconductor taken out before pH adjustment
G3: Amount of measurement liquid (g)
S _SiO2 : Area of the silicon oxide film (cm ² ) in the wafer having a single layer film of silicon oxide

The metal residue removability was determined from the calculated total amount of each metal ion elution amount according to the following criteria.
○: 15ng / cm ² or more ^{△: 10ng / cm 2 ~15ng /} cm 2
X: Less than 10 ng / cm ²

<Measuring method of abrasive removability>
The evaluation of the abrasive grain removability was performed by immersing a wafer having a silicon nitride single layer film in a CMP slurry used in a CMP process for tungsten wiring and then immersing it in a cleaning agent for tungsten alloy wiring semiconductor. .
After the washed wafer was dried, the remaining degree of abrasive grains per field of view was observed using an SEM (scanning electron microscope). It was determined that the smaller the number of remaining abrasive grains per field of view, the better the abrasive grain removability.

(1) Cleaning a wafer having a silicon nitride single layer film A wafer having a silicon nitride single layer film (manufactured by Adbas Materials Technology, “PE-CVDSiN 1.5 μ”, film thickness of silicon nitride = 1.0 μm) is 10 After being immersed in a 1% aqueous acetic acid solution for 1 minute, it was washed with water.

(2) Contamination treatment with CMP slurry A wafer having a silicon nitride single layer film is immersed in CMP slurry (Cabot, W7000, main component SiO _{2 of} abrasive grains, average particle diameter 0.2 μm) for 1 minute, and then blown with nitrogen And dried. The obtained post-contamination wafer was cut into a length of 1.0 cm × width of 1.5 cm.

(3) Cleaning with a cleaning agent for tungsten wiring semiconductor A wafer having a silicon nitride single layer film is immersed in 10 g of each cleaning agent for tungsten wiring semiconductor for comparison with the present invention, and left at 25 ° C. for 3 minutes, and then nitrided. The wafer having the silicon single layer film was taken out from the cleaning agent and dried by nitrogen blowing.

(4) SEM observation of wafer surface having silicon nitride single layer film after cleaning
The surface of the wafer having the silicon nitride single-layer film after cleaning was observed at a magnification of 10,000 times using SEM (manufactured by Hitachi High-Technology Corporation, model name S-4800).

(5) Evaluation of abrasive grain removability From the SEM image of the wafer surface, the number of remaining abrasive grains per field of view was confirmed, and the abrasive grain removability was determined according to the following criteria.
○: Less than 10 Δ: 10 to 20 ×: 20 or more

As shown in Table 1, the cleaning agents for tungsten wiring semiconductors of Examples 1 to 5 of the present invention gave good results in all three evaluated items.
On the other hand, Comparative Example 1 containing no organic amine (A) had poor metal residue removability and insufficient abrasive removal. Moreover, the comparative example 2 which does not contain a quaternary ammonium hydroxide (B) has poor abrasive removal property, and the comparative example 3 which does not contain a chelating agent (C) has poor metal residue removability. Furthermore, Comparative Example 4 containing only the chelating agent (C) and oxalic acid had insufficient tungsten corrosion resistance and poor abrasive removal performance.

The tungsten and tungsten alloy wiring semiconductor cleaning agent of the present invention is excellent in the removal of abrasive grains derived from abrasives and the removal of metal residues on the insulating film, and the corrosion resistance of tungsten wiring. Or it can use suitably as a washing | cleaning agent used in the process following the CMP process in the semiconductor manufacturing process which forms a tungsten alloy wiring.

Claims (9)

A cleaning agent used in a process subsequent to chemical mechanical polishing in a semiconductor manufacturing process for forming tungsten or tungsten alloy wiring, wherein the chain polyamine (A2), quaternary ammonium hydroxide ( B), a chelating agent (C), and water (W) , having a pH of 7.0 to 14.0,
The chain polyamine (A2) is propylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, 2-hydroxyethylaminopropylamine, diethanolaminopropylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylene. Heptamine, iminobispropylamine, bis (hexamethylene) triamine, pentaethylenehexamine, aniline, phenylenediamine, tolylenediamine, xylylenediamine, methylenedianiline, diphenyletherdiamine, naphthalenediamine, anthracenediamine, isophoronediamine, cyclohexylene From diamine, piperazine, N-aminoethylpiperazine, and 1,4-diaminoethylpiperazine. Ru is selected from the group,
Cleaning agent for semiconductor process (D). The chain polyamines (A2) is tetraethylenepentamine a is claim 1, wherein the semiconductor process for cleaning agent (D). It said quaternary ammonium hydroxide (B) is a semiconductor process for cleaning agent according to 請 Motomeko 1 or 2 you express the following general formula (3) (D).

R ^{9 to} R ¹² each independently represent an alkyl group having 1 to 3 carbon atoms which may be partially substituted with a hydroxyl group . The molar ratio of said quaternary ammonium hydroxide (B) and the chain polyamines (A2) (B) / ( A 2) is a semiconductor according to any one of claims 1 to 3, 0.1 to 5.0 Process cleaning agent (D). The molar ratio of the chelating agent (C) with the chain polyamines (A2) is (C) / (A 2) , according to claim 1 to 4 or according to a semiconductor process for detergents is 0.001 to 5.0 (D).   The quaternary ammonium hydroxide (B) comprises tetraalkylammonium hydroxide, (hydroxyalkyl) trialkylammonium hydroxide, bis (hydroxyalkyl) dialkylammonium hydroxide, and tris (hydroxyalkyl) alkylammonium hydroxide. The cleaning agent for semiconductor processes (D) according to claim 3, which is selected from the group.   4. The semiconductor process cleaning according to claim 3, wherein the quaternary ammonium hydroxide (B) is selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, and (hydroxyethyl) trimethylammonium hydroxide. Agent (D). The chelating agent (C) is sodium pyrophosphate, sodium tripolyphosphate, potassium trimetaphosphate, sodium tetrametaphosphate, dimethylglyoxime, 8-oxyquinoline, porphyrin, ethylenediaminediacetic acid and its metal salt neutralized product, ethylenediaminetetraacetic acid And its metal salt neutralized product, hexylenediamine diacetic acid and its metal salt neutralized product, hydroxyethyliminodiacetic acid and its metal salt neutralized product, nitrilotriacetic acid trisodium, hydroxyethylethylenediaminetriacetic acid trisodium, diethylenetriamine-5 Acetic acid pentasodium, triethylenetotolamine hexaacetic acid hexasodium, dihydroxyethylglycine, glycine, L-glutamic acid diacetic acid tetrasodium salt, oxalic acid, disodium maleate, adipic acid, sebacic acid, 2. One selected from the group consisting of tylacetone, hexane-2,4-dione, 3-ethylnonane-4,7-dione, sodium polyacrylate, and poly [sodium 2-hydroxyacrylate]. -Cleaning agent (D) for semiconductor processes in any one of 4 .   A method of cleaning a semiconductor following chemical mechanical polishing, the method comprising removing abrasive grains derived from an abrasive and metal residues on an insulating film. Contacting the surface of the semiconductor with a cleaning agent, wherein the surface of the semiconductor comprises tungsten or tungsten alloy wiring.