JP2016072582A - Chemical mechanical polishing aqueous dispersion and chemical mechanical polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a chemical mechanical polishing aqueous dispersion which enables the large reduction in polishing rate for a Group III-V or Group IV metal film while achieving a high polishing rate on SiN film in the step of polishing a face to be polished, which has a Group III-V material or Group IV material, and SiN; and a chemical mechanical polishing method using such a dispersion.SOLUTION: A chemical mechanical polishing aqueous dispersion according to the present invention is arranged for polishing a face to be polished, which has a Group III-V material or Group IV material and SiN. The chemical mechanical polishing aqueous dispersion comprises (A)abrasive grains, and (B)dioxirane expressed by the following general formula (1). (In the formula (1), Rand Rindependently represent an alkyl group, an alkenyl group or an aryl group, which may be substituted with a hydroxy group or carboxy group; further Rand Rmay be bonded to each other to form a cyclic structure with 3-8C.)SELECTED DRAWING: None

Description

  The present invention relates to an aqueous dispersion for chemical mechanical polishing and a chemical mechanical polishing method.

  In recent years, the chemical mechanical polishing (hereinafter also referred to as “CMP”) method is frequently used in planarization of an interlayer insulating film, formation of a metal plug, and formation of embedded wiring (damascene wiring) in an LSI manufacturing process, particularly a multilayer wiring forming process. Has been. Silicide has been used as a material for the source and drain of the gate, but in a logic device that requires higher speed performance, a III-V group material having higher carrier mobility can be used instead. The introduction of Group IV materials is considered promising.

The III-V group material and the IV group material are expected to be applied to, for example, the source and drain of the FIN-FET. As for the formation order, the source and drain are formed before the step of forming the gate dielectric layer on the channel and the step of forming the gate on the gate dielectric layer. As an example of the source and drain formation process, a photoresist is applied on a SiN film, exposed and developed to form a pattern, and then a trench is formed by etching SiN / SiO ₂ / Si in this order as a mask. Then, a group III-V material or a group IV material is deposited by CVD to form a group III-V or group IV metal film, and then a group III-V or group IV metal film or SiN film other than the trench is formed by CMP. (For example, refer to Patent Document 1).

  Conventionally, chemical mechanical polishing aqueous dispersions used in such polishing processes use zirconia particles, ceria particles, alumina particles, silica particles, etc. as abrasive grains, and sulfuric acid, nitric acid according to the chemical characteristics of the polishing film. In addition, compositions adjusted to a suitable pH with acetic acid, potassium hydroxide, ammonia and the like have been used. In CMP for removing the III-V or IV group metal film, mechanical removal of the oxide layer formed on the surface layer of the III-V or IV group metal film and the removal of the metal ions exposed after the removal of the oxide layer are performed. Removal by dissolution and competitive polishing proceed simultaneously, but by adjusting the composition of the aqueous dispersion for chemical mechanical polishing so that mechanical removal becomes dominant, it is preferential from the convex portion that becomes relatively high pressure. Polishing and planarization can be performed, and the thickness of the III-V or IV group metal film in the trench at the end of polishing can be controlled.

  In the formation of the source and drain described above, when the SiN film and the III-V group or IV group metal film are polished using the chemical mechanical polishing aqueous dispersion, not only the polishing rate above a certain level but also the source and drain surface Smoothness is particularly important.

JP 2011-61196 A

  However, in the formation of the source / drain as described above, in the process of removing the SiN film using the conventional chemical mechanical polishing aqueous dispersion, the group III-V or IV formed in the previous process is used. Since the group metal film is also polished at the same time, there is a problem that smoothness is impaired and impurities are mixed in, causing fluctuations in FET performance.

  Accordingly, some aspects of the present invention provide a high polishing rate for a SiN film in a step of polishing a surface to be polished having a Group III-V material or a Group IV material and SiN by solving the above problems. On the other hand, an aqueous dispersion for chemical mechanical polishing capable of significantly reducing the polishing rate for a III-V or IV group metal film and a chemical mechanical polishing method using the same are provided.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

（式（１）中、Ｒ^１およびＲ^２はそれぞれ独立に、ヒドロキシ基もしくはカルボキシ基で置換されていてもよい、アルキル基、アルケニル基またはアリール基を表す。また、Ｒ^１とＲ^２が結合して炭素数３〜８の環状構造を形成していてもよい。） [Application Example 1]
One aspect of the chemical mechanical polishing aqueous dispersion according to the present invention is:
An aqueous dispersion for chemical mechanical polishing for polishing a surface to be polished having a III-V material or a IV material and SiN,
(A) abrasive grains;
(B) dioxirane represented by the following general formula (1);
It is characterized by containing.

(In Formula (1), R ¹ and R ² each independently represents an alkyl group, an alkenyl group or an aryl group which may be substituted with a hydroxy group or a carboxy group. Also, R ¹ and R ² are bonded. And a cyclic structure having 3 to 8 carbon atoms may be formed.)

[Application Example 2]
In the chemical mechanical polishing aqueous dispersion of Application Example 1,
Said (A) abrasive grain can be colloidal silica.

[Application Example 3]
In the chemical mechanical polishing aqueous dispersion of Application Example 1 or Application Example 2,
(A) The average secondary particle diameter of the abrasive grains may be 10 nm or more and 150 nm or less.

（式（２）中、Ｚ^＋は、水素イオン、アンモニウムイオンまたは１価の金属イオンを表す。）

（式（３）中、Ｒ^１およびＲ^２はそれぞれ独立に、ヒドロキシ基もしくはカルボキシ基で置換されていてもよい、アルキル基、アルケニル基またはアリール基を表す。また、Ｒ^１とＲ^２が結合して炭素数３〜８の環状構造を形成していてもよい。） [Application Example 4]
In the chemical mechanical polishing aqueous dispersion according to any one of Application Examples 1 to 3,
The component (B) may be a compound produced by a combination of hydrogen peroxide or a compound represented by the following general formula (2) and a compound represented by the following general formula (3).

(In the formula (2), Z ⁺ represents a hydrogen ion, an ammonium ion or a monovalent metal ion.)

(In Formula (3), R ¹ and R ² each independently represents an alkyl group, an alkenyl group or an aryl group, which may be substituted with a hydroxy group or a carboxy group. In addition, R ¹ and R ² are bonded. And a cyclic structure having 3 to 8 carbon atoms may be formed.)

[Application Example 5]
In the chemical mechanical polishing aqueous dispersion of Application Example 4,
The compound represented by the general formula (2) may be ammonium persulfate.

[Application Example 6]
In the chemical mechanical polishing aqueous dispersion of Application Example 4 or Application Example 5,
The compound represented by the general formula (3) may be acetone or fructose.

[Application Example 7]
In the chemical mechanical polishing aqueous dispersion according to any one of Application Examples 1 to 6,
The pH can be 5 or higher.

[Application Example 8]
One aspect of the chemical mechanical polishing method according to the present invention is:
Using the chemical mechanical polishing aqueous dispersion according to any one of Application Example 1 to Application Example 7, a surface to be polished having a III-V group material or a Group IV material and SiN is polished.

  According to the chemical mechanical polishing aqueous dispersion, a high polishing rate for the SiN film can be obtained when polishing a polished surface having a Group III-V material or a Group IV material and SiN. The polishing rate for the group IV or group IV metal film can be greatly reduced. Thereby, in the process of removing the SiN film in the formation of the source / drain, the smoothness becomes extremely good, so that it is possible to prevent the fluctuation of the FET performance due to the mixing of impurities.

It is sectional drawing which shows typically a specific example of the chemical mechanical polishing method which concerns on this Embodiment. It is sectional drawing which shows typically a specific example of the chemical mechanical polishing method which concerns on this Embodiment. It is a perspective view which shows a chemical mechanical polishing apparatus typically.

  Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, Various modifications implemented in the range which does not change the summary of this invention are also included.

（式（１）中、Ｒ^１およびＲ^２はそれぞれ独立に、ヒドロキシ基もしくはカルボキシ基で置換されていてもよい、アルキル基またはアリール基を表す。また、Ｒ^１とＲ^２が結合して炭素数３〜８の環状構造を形成していてもよい。） 1. Chemical mechanical polishing aqueous dispersion The chemical mechanical polishing aqueous dispersion according to one embodiment of the present invention is a chemical mechanical polishing for polishing a surface to be polished having a Group III-V material or a Group IV material and SiN. An aqueous dispersion comprising (A) abrasive grains and (B) dioxirane represented by the following general formula (1).

(In Formula (1), R ¹ and R ² each independently represents an alkyl group or an aryl group which may be substituted with a hydroxy group or a carboxy group. Also, R ¹ and R ² are bonded to form a carbon. (You may form the cyclic structure of several 3-8.)

  The chemical mechanical polishing aqueous dispersion according to the present embodiment is used for polishing a surface to be polished having a Group III-V material or a Group IV material and SiN. The III-V group material is a general term for compounds of Group III elements of the periodic table such as boron, aluminum, gallium, indium and thallium and Group V elements such as nitrogen, phosphorus, arsenic, antimony and bismuth. Examples of the III-V group material include boron nitride (BN), gallium phosphide (GaP), indium phosphide (InP), gallium arsenide (GaAs), indium antimonide (InSb), and indium gallium arsenide (InGaAs). ), Indium gallium antimonide (InGaSb), and the like. Examples of the group IV material include germanium (Ge) and silicon germanium (SiGe).

  III-V group materials and IV group materials are expected to be applied to the source and drain of FIN-FETs, for example, but using conventional chemical mechanical polishing aqueous dispersions, group III-V materials and group IV materials Even if chemical mechanical polishing was performed, the etching action worked strongly, and it was difficult to obtain a smooth polished surface. The chemical mechanical polishing aqueous dispersion according to the present embodiment can realize high-speed polishing of the SiN film, but can greatly reduce the polishing rate of the III-V group material and the IV group material. In the step of removing the SiN film, the smoothness is extremely good, and there is an effect that the fluctuation of the FET performance due to the mixing of impurities can be prevented.

  First, each component constituting the chemical mechanical polishing aqueous dispersion according to the present embodiment will be described.

1.1. (A) Abrasive Grain The chemical mechanical polishing aqueous dispersion according to this embodiment contains (A) abrasive grains. (A) Abrasive grains have the effect of mechanically polishing the surface to be polished. (A) As an abrasive grain, inorganic particles, such as a silica, a ceria, an alumina, a zirconia, and a titania; Organic particles, such as polymethyl methacrylate, are mentioned.

  Silica particles include: (a) fumed silica synthesized by the fumed method in which silicon chloride, aluminum chloride, titanium chloride or the like is reacted with oxygen and hydrogen in the gas phase; (b) synthesized by hydrolytic condensation from metal alkoxide. And silica synthesized by a sol-gel method; (c) colloidal silica synthesized by an inorganic colloid method in which impurities are removed by purification. Among these, colloidal silica is preferable from the viewpoint of suppressing generation of scratches on the surface to be polished.

  (A) The average secondary particle diameter of the abrasive grains is preferably 10 nm or more and 150 nm or less, more preferably 20 nm or more and 90 nm or less. When the average secondary particle diameter is within the above range, a stable chemical mechanical polishing aqueous dispersion is obtained in which the polishing rate for the SiN film is large, the generation of scratches is suppressed, and the precipitation and separation of particles are difficult to occur. Can do. This average secondary particle size is measured by measuring the intensity of scattered light using a particle size distribution measuring device based on the dynamic light scattering method, obtaining the autocorrelation function by the photon correlation method, and analyzing the cumulant method and the histogram method. Can be obtained by applying.

  (A) Content of abrasive grains is preferably 0.5% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less, with respect to the total mass of the chemical mechanical polishing aqueous dispersion. Especially preferably, it is 2 mass% or more and 8 mass% or less. (A) When the content of the abrasive grains is within the above range, a sufficient polishing rate for the SiN film can be obtained, and a stable chemical mechanical polishing aqueous dispersion in which particles are not easily settled and separated can be easily obtained.

1.2. (B) Dioxirane The chemical mechanical polishing aqueous dispersion according to this embodiment contains (B) dioxirane represented by the following general formula (1) (hereinafter also referred to as “(B) dioxirane”).

（式（１）中、Ｒ^１およびＲ^２はそれぞれ独立に、ヒドロキシ基もしくはカルボキシ基で置換されていてもよい、アルキル基、アルケニル基またはアリール基を表す。また、Ｒ^１とＲ^２が結合して炭素数３〜８の環状構造を形成していてもよい。）

(In Formula (1), R ¹ and R ² each independently represents an alkyl group, an alkenyl group or an aryl group which may be substituted with a hydroxy group or a carboxy group. Also, R ¹ and R ² are bonded. And a cyclic structure having 3 to 8 carbon atoms may be formed.)

Here, when R ¹ and R ² in the formula (1) is an alkyl group is preferably an alkyl group having 1 to 24 carbon atoms. When R ¹ and R ² are alkenyl groups, they are preferably alkenyl groups having 2 to 24 carbon atoms. R ¹ and R ² may also be constituent parts of the same ring system. Particularly preferred in this case is a cyclic structure in which R ¹ and R ² total 3 to 8 carbon atoms.

  Examples of such component (B) include dimethyldioxirane, diethyldioxirane, methylethyldioxirane, diphenyldioxirane, and the like.

  In the chemical mechanical polishing aqueous dispersion according to the present embodiment, (B) dioxirane can be added as it is, but since it is a slightly unstable compound, (B1) an oxidizing agent and (B2) a ketone are combined. By adding, it is preferable to react these in an aqueous dispersion so that (B) dioxirane is produced.

The (B) dioxirane thus produced transfers one oxygen atom to the surface of the SiN film. As a result, the SiN film surface is oxidized and a fragile modified layer is created. Next, (B) dioxirane is reduced to (B2) ketone and used in the next cycle. By repeating this cycle, it is considered that high-speed polishing of the SiN film surface is realized. In addition, it is considered that a part of the (B2) ketone has a carbonyl group in the molecule bonded to a group III-V material or a group IV material to form an insoluble complex, thereby forming an insoluble brittle film. As a result, it is considered that excessive etching on the III-V group or IV group metal film is suppressed, and the polishing rate for these films can be reduced.

  On the other hand, when (B2) only the oxidizing agent is added without adding (B2) ketone, (B1) the oxidizing agent is directly applied to the III-V or IV group metal film without passing through (B2) ketone. Therefore, the surface of the III-V or IV group metal film is oxidized to create a fragile modified layer. In addition, since (B2) no ketone is added, the insoluble brittle film as described above is not formed on the surface of the III-V or IV group metal film. Therefore, it is considered that the polishing rate for the III-V group or IV group metal film cannot be reduced.

  In addition, the said mechanism is based on estimation and the chemical mechanical polishing aqueous dispersion according to the present embodiment is not limited to the above mechanism.

（式（２）中、Ｚ^＋は、水素イオン、アンモニウムイオンまたは１価の金属イオンを表す。） Examples of (B1) oxidizing agent include hydrogen peroxide or a compound represented by the following general formula (2).

(In the formula (2), Z ⁺ represents a hydrogen ion, an ammonium ion or a monovalent metal ion.)

  Specific examples of the compound represented by the general formula (2) include peroxodisulfuric acid, sodium persulfate, potassium persulfate, and ammonium persulfate. These (B1) oxidizing agents may be used individually by 1 type, and may be used in combination of 2 or more type. Of these (B1) oxidizing agents, ammonium persulfate is particularly preferable in view of oxidizing power, compatibility with the film to be polished, ease of handling, and the like.

  (B1) The content of the oxidizing agent is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 8% by mass or less, with respect to the total mass of the chemical mechanical polishing aqueous dispersion. Especially preferably, it is 0.5 mass% or more and 5 mass% or less. When the content of (B1) oxidizing agent is less than the above range, (B2) the ketone cannot be sufficiently oxidized, and a high polishing rate for the SiN film may not be obtained. On the other hand, if it exceeds the above range, the etching action on the III-V or IV group metal film becomes too strong, and the polishing rate of the III-V or IV group metal film tends to increase.

（式（３）中、Ｒ^１およびＲ^２はそれぞれ独立に、ヒドロキシ基もしくはカルボキシ基で置換されていてもよい、アルキル基、アルケニル基またはアリール基を表す。また、Ｒ^１とＲ^２が結合して炭素数３〜８の環状構造を形成していてもよい。） (B2) As ketone, the compound shown by following General formula (3) is mentioned, for example.

(In Formula (3), R ¹ and R ² each independently represents an alkyl group, an alkenyl group or an aryl group, which may be substituted with a hydroxy group or a carboxy group. In addition, R ¹ and R ² are bonded. And a cyclic structure having 3 to 8 carbon atoms may be formed.)

Here, when R ¹ and R ² in the formula (3) is an alkyl group is preferably an alkyl group having 1 to 24 carbon atoms. When R ¹ and R ² are alkenyl groups, they are preferably alkenyl groups having 2 to 24 carbon atoms. R ¹ and R ² may also be constituent parts of the same ring system. Particularly preferred in this case is a cyclic structure in which R ¹ and R ² total 3 to 8 carbon atoms.

  Specific examples of the compound represented by the general formula (3) include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, alkyl phenyl ketone, cyclopentanone, cyclohexanone, cycloheptanone, and cyclooctanone. Other examples include ketoses such as dihydroxyacetone, fructose, erythrulose, xylulose, ribulose, psicose, sorbose, tagatose, sedoheptulose, coliose and the like. Among these, acetone and fructose are particularly preferable. The (B2) ketones exemplified above may be used alone or in combination of two or more.

  The content ratio of (B2) ketone is preferably 0.001% by mass or more and 1% by mass or less, more preferably 0.01% by mass or more and 0.5% by mass with respect to the total mass of the chemical mechanical polishing aqueous dispersion. Hereinafter, it is particularly preferably 0.05% by mass or more and 0.2% by mass or less. If the content ratio of (B2) ketone is within the above range, the above-described catalytic cycle of (B2) ketone can be advanced, so that high-speed polishing of the SiN film can be realized. Moreover, since the brittle film of (B2) ketone described above is formed, the polishing rate for the III-V group or IV group metal film can be reduced.

1.3. pH
The pH of the chemical mechanical polishing aqueous dispersion according to the present embodiment is not particularly limited, but under acidic conditions where the pH is less than 5, (B) dioxirane is fragile due to Baeyer-Villiger oxidation, so the pH is 5 or more. Preferably, it is 6 or more and 11 or less, more preferably 7 or more and 10 or less. Examples of the pH adjuster include basic compounds such as potassium hydroxide, ethylenediamine and TMAH (tetramethylammonium hydroxide); organic acids such as phthalic acid, maleic acid and citric acid and salts thereof; nitric acid, hydrochloric acid and sulfuric acid And inorganic acids such as these and salts thereof.

1.4. Other Additives To the chemical mechanical polishing aqueous dispersion according to the present embodiment, a surfactant, a water-soluble polymer, an anticorrosive, and the like can be added as necessary.

  Surfactants include cationic surfactants such as aliphatic amine salts and aliphatic ammonium salts; anionic surfactants such as carboxylate salts, sulfonate salts, sulfate ester salts, and phosphate ester salts; ether type interfaces Nonionic surfactants such as an activator, an ether ester type surfactant, an ester type surfactant, and an acetylene type surfactant may be mentioned. The content of the surfactant is 1% by mass or less, preferably 0.001% by mass or more and 0.1% by mass or less, with respect to the total mass of the chemical mechanical polishing aqueous dispersion.

  Examples of the water-soluble polymer include polyacrylamide, polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, and hydroxyethyl cellulose. The content of the water-soluble polymer may be adjusted in such a range that the viscosity of the chemical mechanical polishing aqueous dispersion is less than 2 mPa · s.

  Anticorrosives include benzotriazole and its derivatives. The content of the anticorrosive is 1% by mass or less, preferably 0.001% by mass or more and 0.1% by mass or less, based on the total mass of the chemical mechanical polishing aqueous dispersion.

1.5. Method for Preparing Chemical Mechanical Polishing Aqueous Dispersion The chemical mechanical polishing aqueous dispersion according to the present embodiment can be prepared by dissolving or dispersing each component in a solvent such as water. The method of dissolving or dispersing is not particularly limited, and any method may be applied as long as it can be uniformly dissolved or dispersed. Also, the mixing order and mixing method of each component are not particularly limited. In addition, the chemical mechanical polishing aqueous dispersion according to the present embodiment can be prepared as a concentrated stock solution and diluted with a solvent such as water when used.

2. Chemical mechanical polishing method The chemical mechanical polishing method according to the present embodiment uses the above-described chemical mechanical polishing aqueous dispersion to polish a surface to be polished having a Group III-V material or a Group IV material and SiN. It is characterized by doing. As described above, the III-V group material and the IV group material are expected to be applied to the source / drain of, for example, a FIN-FET. Hereinafter, a specific example of the chemical mechanical polishing method according to the present embodiment will be described in detail with reference to the drawings.

  FIG. 1A to FIG. 2G are cross-sectional views schematically showing a process of forming a source / drain using the chemical mechanical polishing method according to the present embodiment.

First, as shown in FIG. 1A, a silicon oxide film 12 (SiO ₂ ) as a stopper is formed on a silicon substrate 10 (Si) using a CVD method or a thermal oxidation method. Further, a silicon nitride film 14 (SiN) is formed on the silicon oxide film 12 using a CVD method. Next, as shown in FIG. 1B, a photoresist 16 is applied, exposed and developed on the silicon nitride film 14 to form a pattern. Then, as shown in FIG. 1C, a trench 18 is formed by etching in the order of SiN / SiO ₂ / Si using the photoresist 16 as a mask. Next, as shown in FIG. 1D, a group III-V material is deposited so as to fill the trench 18 by a CVD method to form a group III-V metal film 20. In this way, the workpiece 100 is obtained.

  In order to remove the III-V group metal film 20 other than the trench deposited on the silicon nitride film 14 of the workpiece 100, a chemical mechanical polishing aqueous dispersion for the group III-V metal film is used. Perform chemical mechanical polishing. Then, the silicon nitride film 14 becomes a stopper, and polishing can be stopped on the surface of the silicon nitride film 14. In this way, as shown in FIG. 2E, the III-V group metal film 20 in portions other than the trench can be removed.

  Subsequently, in order to remove the silicon nitride film 14, chemical mechanical polishing is performed using the chemical mechanical polishing aqueous dispersion according to the present embodiment. Then, the silicon nitride film 14 is preferentially removed, and the silicon oxide film 12 becomes a stopper, and polishing can be stopped on the surface of the silicon oxide film 12. In this way, as shown in FIG. 2F, the silicon nitride film 14 is removed, and the III-V group metal film 20 in the trench remains as a convex portion.

  Finally, by using a chemical mechanical polishing aqueous dispersion whose composition is adjusted so that mechanical removal is dominant, it is possible to preferentially polish and planarize from a relatively high-pressure convex portion. The portion of the III-V group metal film 20 is polished and removed while controlling the thickness. Thus, a source / drain as shown in FIG. 2G is obtained.

In the chemical mechanical polishing described above, for example, a chemical mechanical polishing apparatus 200 as shown in FIG. 3 can be used. FIG. 3 is a perspective view schematically showing the chemical mechanical polishing apparatus 200. The slurry 44 is supplied from the slurry supply nozzle 42 and the carrier head 52 holding the semiconductor substrate 50 is brought into contact with the turntable 48 to which the polishing cloth 46 is attached while rotating. In FIG. 3, the water supply nozzle 54 and the dresser 56 are also shown.

The polishing load of the carrier head 52 can be selected within the range of 10 to 1000 hPa, and preferably 30 to 500 hPa. Moreover, the rotation speed of the turntable 48 and the carrier head 52 can be suitably selected within the range of 10 to 400 rpm, and preferably 30 to 150 rpm. Flow rate of the slurry 44 supplied from the slurry supply nozzle 42 may be selected within the range of 10~1,000cm ³ / min, preferably 50~400cm ³ / min.

  In this polishing step, a commercially available chemical mechanical polishing apparatus can be used. As a commercially available chemical mechanical polishing apparatus, for example, “EPO-112”, “EPO-222” manufactured by Ebara Manufacturing Co., Ltd .; “LGP-510”, “LGP-552” manufactured by LAPMASTER SFT, Inc .; A model “Mirra”, etc., is available.

3. Examples Hereinafter, the present invention will be described by way of examples. However, the present invention is not limited to these examples. “Part” and “%” in Examples and Comparative Examples are based on mass unless otherwise specified.

3.1. Preparation of aqueous dispersion containing colloidal silica particles 3 volumes of tetraethoxysilane and 1 volume of ethanol were mixed to obtain a raw material solution. A reaction solvent in which ethanol, ion-exchanged water, and ammonia were mixed in advance was charged into the reaction vessel. While cooling so as to maintain the temperature of the reaction solvent at 20 ° C., 1 volume of the raw material solution per 9 volumes of the reaction solvent was dropped into the reaction tank to obtain an alcohol dispersion of colloidal silica.

  Next, using a rotary evaporator, the operation of removing the alcohol while adding ion-exchanged water was repeated several times while maintaining the temperature of the obtained alcohol dispersion at 80 ° C. By this operation, an aqueous dispersion containing colloidal silica particles was prepared. A sample obtained by taking out a part of this aqueous dispersion and diluting with ion-exchanged water was measured using a dynamic light scattering particle size distribution analyzer (manufactured by Horiba, Ltd., model “LB550”), and the arithmetic average diameter was determined as the average secondary particle. It was 70 nm when measured as a diameter.

3.2. Preparation of Chemical Mechanical Polishing Aqueous Dispersion 50 parts by mass of ion-exchanged water, 1.5 parts by mass of the aqueous dispersion containing the colloidal silica particles obtained above in terms of silica, 4 parts by mass of ammonium persulfate, 0. 1 part by weight was added and these were stirred for 15 minutes. Finally, after adding potassium hydroxide and ion-exchanged water so that the total amount of all components becomes 100 parts by mass and the predetermined pH shown in Table 1, chemical mechanical polishing is performed by filtering with a filter having a pore size of 1 μm. An aqueous dispersion A was obtained.

  The chemical mechanical polishing was carried out in the same manner as the preparation method of the chemical mechanical polishing aqueous dispersion A except that the components shown in Table 1 were added instead of ammonium persulfate or fructose and the pH was adjusted to that shown in Table 1. Aqueous dispersions B to M were prepared.

3.3. Evaluation method 3.3.1. Blanket Wafer Evaluation A chemical mechanical polishing apparatus (Lap Master SFT, model “Lap Master LGP-510”) is equipped with a porous polyurethane polishing pad (Nita Haas, product number “IC1000”), and chemical mechanical polishing is performed. While supplying any one of the aqueous dispersions A to M, a chemical mechanical polishing treatment was performed for 2 minutes under the following polishing conditions using a single crystal InP substrate or SiN substrate having a diameter of 3 inches as an object to be polished. The polishing rate was evaluated by the method. The results are shown in Table 1.
<Polishing conditions>
Polishing apparatus: manufactured by Lapmaster SFT, model “Lapmaster LGP-510”
Polishing pad: Rodel Nitta Co., Ltd. “IC1000 / K-Groove”
・ Chemical mechanical polishing aqueous dispersion supply speed: 100 mL / min ・ Surface plate rotation speed: 90 rpm
・ Rotation speed of polishing head: 90 rpm
Polishing head pressing pressure: 100 hPa

<Evaluation of polishing rate of InP substrate>
The weight of the single crystal InP substrate after polishing treatment was measured using a precision balance, the film thickness was calculated from the weight and specific gravity decreased by chemical mechanical polishing, and the polishing rate was calculated from the polishing time. The evaluation criteria are as follows, and the polishing rate and evaluation results are also shown in Table 1.
・ If the polishing rate of the InP substrate is less than 10 Å / min, “Good”
・ If the polishing rate of the InP substrate is 10 Å / min or more, it is determined that the defect is “x”

<Evaluation of polishing rate of SiN substrate>
The weight of the single crystal SiN substrate after the polishing treatment was measured using a precision balance, the film thickness was calculated from the weight and specific gravity reduced by chemical mechanical polishing, and the polishing rate was calculated from the polishing time. The evaluation criteria are as follows, and the polishing rate and evaluation results are also shown in Table 1.
・ If the polishing rate of the SiN substrate is 200 Å / min or more, “Good”
・ If the polishing rate of the SiN substrate is less than 200 Å / min, it is determined that it is defective.

3.4. Evaluation results The composition of the chemical mechanical polishing aqueous dispersions used in Examples 1 to 7 and Comparative Examples 1 to 6 and the evaluation results are shown in Table 1 below.

As can be seen from Table 1 above, when the chemical mechanical polishing aqueous dispersions of Examples 1 to 7 were used, a low polishing rate was achieved in polishing the InP film, and the InP film was dissolved by etching. It was found that it was reduced.

  In the chemical mechanical polishing aqueous dispersions of Comparative Examples 1 to 6, although there was a sufficient SiN polishing rate, the polishing rate was high in polishing the InP film.

  The chemical mechanical polishing aqueous dispersion according to the present invention includes GaAs, GaN, InP, InGaAs, GaN, GaSb, InAs, InSb, AlN, AlGaN, InGaAs, InGaSb, and other III-V group materials, Ge, SiGe, etc. The group IV material is mainly polished, but Cu, Al, W, Ti, TiN, Ta, TaN, V, Mo, Ru, Zr, Mn, Ni, Fe, Ag, Mg, Mn, Hf or Si It is expected to be effective for a layer composed of the above compound and a laminated structure including a layer composed of these elements or compounds.

  The present invention is not limited to the above embodiment, and various modifications can be made. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). The present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration. Furthermore, the present invention includes a configuration that achieves the same effects as the configuration described in the above embodiment or a configuration that can achieve the same object. Furthermore, the present invention includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

DESCRIPTION OF SYMBOLS 10 ... Silicon substrate, 12 ... Silicon oxide film, 14 ... Silicon nitride film, 16 ... Photoresist, 18 ... Trench, 20 ... III-V group metal film, 42 ... Slurry supply nozzle, 44 ... Slurry, 46 ... Polishing cloth, DESCRIPTION OF SYMBOLS 48 ... Turntable, 50 ... Semiconductor substrate, 52 ... Carrier head, 54 ... Water supply nozzle, 56 ... Dresser, 100 ... To-be-processed object, 200 ... Chemical mechanical polishing apparatus

Claims (8)

An aqueous dispersion for chemical mechanical polishing for polishing a surface to be polished having a III-V material or a IV material and SiN,
(A) abrasive grains;
(B) dioxirane represented by the following general formula (1);
An aqueous dispersion for chemical mechanical polishing, comprising:

(In Formula (1), R ¹ and R ² each independently represents an alkyl group, an alkenyl group or an aryl group which may be substituted with a hydroxy group or a carboxy group. Also, R ¹ and R ² are bonded. And a cyclic structure having 3 to 8 carbon atoms may be formed.)   2. The chemical mechanical polishing aqueous dispersion according to claim 1, wherein the abrasive grains (A) are colloidal silica. 3.   The chemical mechanical polishing aqueous dispersion according to claim 1 or 2, wherein the average secondary particle size of the abrasive grains (A) is 10 nm or more and 150 nm or less. The component (B) is a compound formed by a combination of hydrogen peroxide or a compound represented by the following general formula (2) and a compound represented by the following general formula (3): 4. The chemical mechanical polishing aqueous dispersion according to any one of 3 above.

(In the formula (2), Z ⁺ represents a hydrogen ion, an ammonium ion or a monovalent metal ion.)

(In Formula (3), R ¹ and R ² each independently represents an alkyl group, an alkenyl group or an aryl group, which may be substituted with a hydroxy group or a carboxy group. In addition, R ¹ and R ² are bonded. And a cyclic structure having 3 to 8 carbon atoms may be formed.)   The chemical mechanical polishing aqueous dispersion according to claim 4, wherein the compound represented by the general formula (2) is ammonium persulfate.   The chemical mechanical polishing aqueous dispersion according to claim 4 or 5, wherein the compound represented by the general formula (3) is acetone or fructose.   The aqueous dispersion for chemical mechanical polishing according to any one of claims 1 to 6, wherein the pH is 5 or more.   A polishing surface having a group III-V material or a group IV material and SiN is polished using the chemical mechanical polishing aqueous dispersion according to any one of claims 1 to 7. A chemical mechanical polishing method.

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