JP6068791B2 - Polishing composition - Google Patents

Description

  The present invention has a portion containing a III-V compound material (hereinafter also referred to as a III-V compound material portion) and a portion containing a silicon material such as silicon oxide (hereinafter also referred to as a silicon material portion). The present invention relates to a polishing composition for use in polishing a polishing object. The present invention also relates to a polishing method and a substrate manufacturing method using the polishing composition.

  Group III-V compound materials such as gallium arsenide (GaAs), which have better carrier transport properties than silicon, are expected as next-generation semiconductor channel materials. The III-V compound channel can be formed by polishing a polishing object having a III-V compound material portion and a silicon material portion. In this case, if a polishing composition that can polish the III-V group compound material portion more selectively than the silicon material portion is used, the III-V group compound material portion can be efficiently removed by polishing. is there. Further, since the oxide loss of silicon oxide or the like is reduced, a withstand voltage between the wiring layers is ensured. Further, when performing a photolithography process thereafter, exposure focus is easy because there is little oxide loss, and the process is stabilized (see Patent Document 1). However, for example, a polishing composition as described in Patent Document 2 or Patent Document 3 conventionally used for polishing a group III-V compound semiconductor substrate composed only of a group III-V compound is a group III-V. When used in an application for polishing an object to be polished having a compound material portion and a silicon material portion, a sufficiently high polishing selectivity for a III-V group compound material portion is not exhibited.

JP 11-204520 A Japanese Unexamined Patent Publication No. 63-150155 JP 2004-327614 A

  Accordingly, an object of the present invention is to exhibit a high polishing selectivity for a III-V group compound material portion when used in an application for polishing a polishing object having a III-V group compound material portion and a silicon material portion. An object of the present invention is to provide a polishing composition that can be used, and to provide a polishing method and a substrate manufacturing method using the polishing composition.

In order to achieve the above object, in the first aspect of the present invention, in a polishing object having a group III-V compound material part and a silicon material part separately, a part containing a group III-V compound material; A polishing composition used for simultaneously polishing a portion containing a silicon material, an abrasive having an average primary particle size of 40 nm or less, an oxidizing agent, and a surface OH group of the silicon material portion There is provided a polishing composition containing a suppressor compound that binds and suppresses hydrolysis of a silicon material portion .

In the second aspect of the present invention, in a polishing object having a group III-V compound material portion and a silicon material portion separately, a portion containing a group III-V compound material and a portion containing a silicon material are simultaneously used. A polishing composition used in a polishing application, comprising abrasive grains, an oxidizing agent, and a suppressor compound that binds to a surface OH group of the silicon material portion and functions to suppress hydrolysis of the silicon material portion. The polishing composition containing this is provided.

It is preferable that the polishing composition of the said 1st and 2nd aspect has neutral pH .
In the third aspect of the present invention, in the polishing object having the group III-V compound material part and the silicon material part separately using the polishing composition of the first or second aspect , III-V Provided is a method for simultaneously polishing a portion containing a group compound material and a portion containing a silicon material .

In the fourth aspect of the present invention, in the polishing object having the III-V group compound material part and the silicon material part separately using the polishing composition of the first or second aspect , III-V Provided is a method for manufacturing a substrate by simultaneously polishing a portion containing a group compound material and a portion containing a silicon material .

  ADVANTAGE OF THE INVENTION According to this invention, when using in the use which grind | polishes the grinding | polishing target object which has a III-V group compound material part and a silicon material part, the high grinding | polishing selectivity with respect to a III-V group compound material part can be exhibited. A polishing composition, a polishing method using the polishing composition, and a method for manufacturing a substrate are provided.

First Embodiment Hereinafter, a first embodiment of the present invention will be described.
The polishing composition of the present embodiment is prepared by mixing specific abrasive grains and an oxidizing agent in water. Accordingly, the polishing composition contains specific abrasive grains and an oxidizing agent.

  This polishing composition is used for polishing a polishing object having a III-V compound material portion and a silicon material portion, and more specifically, for polishing a polishing object to produce a substrate. Used for the purpose of selectively polishing the compound material portion. Examples of III-V group compound materials include gallium phosphide (GaP), indium phosphide (InP), gallium arsenide (GaAs), indium arsenide (InAs), indium antimonide (InSb), and the like. Examples of the silicon material include polysilicon, silicon oxide, silicon nitride, and the like.

(Abrasive grains)
The abrasive grains contained in the polishing composition have an average primary particle size of 40 nm or less. When abrasive grains having a small average primary particle diameter of 40 nm or less are used, the polishing rate of the silicon material portion by the polishing composition is higher than that when abrasive grains having an average primary particle diameter exceeding 40 nm are used. There is an advantage that the polishing rate of the III-V group compound material portion is greatly reduced. In addition, the value of the average primary particle diameter of an abrasive grain can be calculated based on the specific surface area of the abrasive grain measured by BET method, for example.

  The abrasive grains in the polishing composition may be either inorganic particles or organic particles. Specific examples of the inorganic particles include particles made of a metal oxide such as silica, alumina, ceria, titania and the like. Specific examples of the organic particles include polymethyl methacrylate (PMMA) particles. Among these, silica particles are preferable, and colloidal silica is particularly preferable.

  The content of abrasive grains in the polishing composition is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. As the content of the abrasive grains decreases, the material cost of the polishing composition can be suppressed, and the aggregation of the abrasive grains is less likely to occur.

  The average secondary particle diameter of the abrasive grains is preferably 170 nm or less, more preferably 150 nm or less, and still more preferably 120 nm or less. As the average secondary particle diameter of the abrasive grains decreases, it becomes easier to obtain a polished surface with less scratches by polishing the object to be polished using the polishing composition. The value of the average secondary particle diameter of the abrasive grains can be measured by, for example, a laser light scattering method.

(Oxidant)
Although the kind of oxidizing agent contained in polishing composition is not specifically limited, It is preferable to have a standard electrode potential of 0.3V or more. When an oxidizing agent having a standard electrode potential of 0.3 V or higher is used, the III-V group compound material by the polishing composition is used compared to the case of using an oxidizing agent having a standard electrode potential of less than 0.3 V. There is an advantage that the polishing rate of the portion is improved. Specific examples of the oxidizing agent having a standard electrode potential of 0.3 V or more include hydrogen peroxide, sodium peroxide, barium peroxide, organic oxidizing agent, ozone water, silver (I I) salt, iron (I I I) Permanganate, chromic acid, dichromic acid, peroxodisulfuric acid, peroxophosphoric acid, peroxosulfuric acid, peroxoboric acid, performic acid, peracetic acid, perbenzoic acid, perphthalic acid, hypochlorous acid, hypochlorous acid Examples include bromic acid, hypoiodous acid, chloric acid, chlorous acid, perchloric acid, bromic acid, iodic acid, periodic acid, sulfuric acid, persulfuric acid, citric acid, dichloroisocyanuric acid, and salts thereof. Among these, hydrogen peroxide, ammonium persulfate, and sodium dichloroisocyanurate are preferable because the polishing rate of the group III-V compound material portion by the polishing composition is greatly improved.

The standard electrode potential is expressed by the following formula when all chemical species involved in the oxidation reaction are in the standard state.
E0 = −ΔG0 / nF = (RT / nF) lnK
Here, E0 is the standard electrode potential, ΔG0 is the standard Gibbs energy change of the oxidation reaction, K is its parallel constant, F is the Faraday constant, T is the absolute temperature, and n is the number of electrons involved in the oxidation reaction. Accordingly, since the standard electrode potential varies depending on the temperature, the standard electrode potential at 25 ° C. is adopted in this specification. The standard electrode potential of the aqueous solution system is described in, for example, the revised 4th edition, Chemical Handbook (Basic Edition) II, pp 464-468 (Edited by Chemical Society of Japan).

  The content of the oxidizing agent in the polishing composition is preferably 0.01 mol / L or more, more preferably 0.1 mol / L or more. As the content of the oxidizing agent increases, the polishing rate of the III-V group compound material portion by the polishing composition is improved.

  The content of the oxidizing agent in the polishing composition is also preferably 100 mol / L or less, more preferably 50 mol / L or less. As the content of the oxidizing agent decreases, the material cost of the polishing composition can be reduced, and the load on the processing of the polishing composition after polishing, that is, the waste liquid treatment can be reduced.

(PH adjuster)
The pH of the polishing composition is preferably neutral, more specifically in the range of 6-8. When the pH is neutral, there is an advantage that the polishing rate of the silicon material portion by the polishing composition is decreased.

  A pH adjusting agent may be used to adjust the pH of the polishing composition to a desired value. The pH adjuster to be used may be either acid or alkali, and may be any of inorganic and organic compounds.

According to this embodiment, the following effects can be obtained.
In the polishing composition of this embodiment, abrasive grains having a small average primary particle diameter of 40 nm or less are used in order to reduce the polishing rate of the silicon material portion by the polishing composition. Therefore, this polishing composition has high polishing selectivity for the III-V group compound material portion.

  When the pH of the polishing composition is neutral, the polishing rate of the silicon material portion by the polishing composition is further reduced, so that the polishing selectivity of the polishing composition with respect to the III-V compound material portion Is further improved.

Second Embodiment Hereinafter, a second embodiment of the present invention will be described.
The polishing composition of the second embodiment is prepared by mixing abrasive grains, an oxidizing agent, and a suppressor compound with water. Therefore, polishing composition contains an abrasive grain, an oxidizing agent, and a suppressor compound.

  The polishing composition of the second embodiment also has a III-V group compound material portion such as gallium arsenide and a silicon material portion such as silicon oxide, as in the polishing composition of the first embodiment. It is used for the purpose of selectively polishing a group III-V compound material in an application for polishing an object, more specifically in an application for polishing a polishing object and manufacturing a substrate.

(Abrasive grains)
The abrasive grains contained in the polishing composition of the second embodiment do not need to have an average primary particle size of 40 nm or less. Except for this point, the abrasive grains in the polishing composition of the first embodiment It is the same as the abrasive grains contained in.

(Oxidant)
The oxidizing agent contained in the polishing composition of the second embodiment is the same as the oxidizing agent contained in the polishing composition of the first embodiment.

(Suppressor compound)
The suppressor compound contained in the polishing composition of the second embodiment functions to bind to the surface OH group of the silicon material portion and suppress hydrolysis of the silicon material portion. Specifically, it is considered that a hydrogen bond is formed between the surface OH group of the silicon material portion and the oxygen atom of the suppressor compound. Further, it is considered that a hydrogen bond is formed between the surface OH group of the silicon material portion and the nitrogen atom of the suppressor compound. Therefore, when a suppressor compound is used, there is an advantage that the polishing rate of the silicon material portion by the polishing composition is reduced. Considering this mechanism, the suppressor compound is preferably a compound having an oxygen atom and a nitrogen-containing compound having a nitrogen atom. Specific examples of suppressor compounds having an oxygen atom include 1-propanol, 2-propanol, 2-propyn-1-ol, allyl alcohol, ethylene cyanohydrin, 1-butanol, 2-butanol, (S)-(+)- 2-butanol, 2-methyl-1-propanol, t-butyl alcohol, perfluoro-t-butyl alcohol, crotyl alcohol, 1-pentanol, 2,2-dimethyl-1-propanol, 2-methyl-2- Butanol, 3-methyl-1-butanol, S-amyl alcohol, 1-hexanol, 4-hydroxy-4-methyl-2-pentanone, 4-methyl-2-pentanol, cyclohexanol, DL-3-hexyl alcohol, 1-heptanol, 2-ethylhexyl alcohol, (S)-(+)-2 Octanol, 1-octanol, DL-3-octyl alcohol, 2-hydroxybenzyl alcohol, 2-nitrobenzyl alcohol, 3,5-dihydroxybenzyl alcohol, 3,5-dinitrobenzyl alcohol, 3-fluorobenzyl alcohol, 3-hydroxy Benzyl alcohol, 4-fluorobenzyl alcohol, 4-hydroxybenzyl alcohol, benzyl alcohol, m- (trifluoromethyl) benzyl alcohol, m-aminobenzyl alcohol, m-nitrobenzyl alcohol, o-aminobenzyl alcohol, o-hydroxybenzyl Alcohol, p-hydroxybenzyl alcohol, p-nitrobenzyl alcohol, 2- (p-fluorophenyl) ethanol, 2-aminophenethyl alcohol, 2- Toxibenzyl alcohol, 2-methyl-3-nitrobenzyl alcohol, 2-methylbenzyl alcohol, 2-nitrophenethyl alcohol, 2-phenylethanol, 3,4-dimethylbenzyl alcohol, 3-methyl-2-nitrobenzyl alcohol, 3 -Methyl-4-nitrobenzyl alcohol, 3-methylbenzyl alcohol, 4-fluorophenethyl alcohol, 4-hydroxy-3-methoxybenzyl alcohol, 4-methoxybenzyl alcohol, 4-methyl-3-nitrobenzyl alcohol, 5-methyl 2-nitrobenzyl alcohol, DL-α-hydroxyethylbenzene, o- (trifluoromethyl) benzyl alcohol, p- (trifluoromethyl) benzyl alcohol, p-aminophenethyl alcohol, p- Hydroxyphenyl ethanol, p- methylbenzyl alcohol and S- pheneticillin alcohols such as chill alcohol,
Phenols such as 4-methylphenol, 4-ethylphenol and 4-propylphenol,
Glycerin ester, sorbitan ester, methoxyacetic acid, ethoxyacetic acid, 3-ethoxypropionic acid, polyoxyethylene (hereinafter referred to as POE) sorbitan fatty acid ester, POE glycol fatty acid ester, POE hexitan fatty acid ester and alanine ethyl ester,
Polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyethylene glycol alkyl ether, polyethylene glycol alkenyl ether, alkyl polyethylene glycol, alkyl polyethylene glycol alkyl ether, alkyl polyethylene glycol alkenyl ether, alkenyl polyethylene glycol, alkenyl polyethylene glycol alkyl ether, alkenyl polyethylene glycol Alkenyl ether, polypropylene glycol alkyl ether, polypropylene glycol alkenyl ether, alkyl polypropylene glycol, alkyl polypropylene glycol alkyl ether, alkyl polypropylene glycol alkenyl ether, alkenyl poly Ethers such as pyrene glycol, alkenyl polypropylene glycol alkyl ether and alkenyl polypropylene glycol alkenyl ether, POE alkylene diglyceryl ether, POE alkyl ether, POE alkyl phenyl ether, POE polypropylene alkyl ether, and polyoxypropylene / polyoxyethylene block / random A copolymer etc. are mentioned.

  Specific examples of suppressor compounds having nitrogen atoms include bishexamethylenetriamine (BHMT), tetramethylammonium hydroxide (TMAH), tetramethylamine (TMA), tetraethylamine (TEA), hydroxylamine (HA), Examples include amine compounds such as polyethyleneamine (PEA), choline hydroxide (CH), dimethylamine, trimethylamine, triethylamine, propylenediamine, ethylenediaminetetraacetic acid (EDTA), sodium diethyldithiocarbamate, and chitosan.

  The content of the suppressor compound in the polishing composition is preferably 10 ppm by mass or more, more preferably 50 ppm by mass or more. As the suppressor compound content increases, the polishing rate of the silicon material portion by the polishing composition decreases.

  The content of the suppressor compound in the polishing composition is also preferably 100000 mass ppm or less, more preferably 50000 mass ppm or less. As the content of the suppressor compound decreases, the material cost of the polishing composition can be reduced, and in addition, the treatment of the polishing composition after polishing, that is, the load of waste liquid treatment can be reduced.

(PH adjuster)
Similarly to the polishing composition of the first embodiment, the polishing composition of the second embodiment is preferably neutral, more specifically within the range of 6-8. When the pH is neutral, there is an advantage that the polishing rate of the silicon material portion by the polishing composition is decreased.

  A pH adjusting agent may be used to adjust the pH of the polishing composition of the second embodiment to a desired value. The pH adjuster to be used may be either acid or alkali, and may be any of inorganic and organic compounds.

According to the second embodiment, the following effects can be obtained.
In the polishing composition of the second embodiment, a suppressor compound is used to reduce the polishing rate of the silicon material portion by the polishing composition. Therefore, this polishing composition has high polishing selectivity for the III-V group compound material portion.

  When the pH of the polishing composition is neutral, the polishing rate of the silicon material portion by the polishing composition is further reduced, so that the polishing selectivity of the polishing composition with respect to the III-V compound material portion Is further improved.

The embodiment may be modified as follows.
-The polishing composition of 1st and 2nd embodiment may contain a 2 or more types of abrasive grain. When the polishing composition of the first embodiment contains two or more kinds of abrasive grains, some abrasive grains do not necessarily have an average primary particle diameter of 40 nm or less.

-The polishing composition of 1st and 2nd embodiment may contain a 2 or more types of oxidizing agent.
-The polishing composition of 2nd Embodiment may contain a 2 or more types of suppressor compound.

  -The polishing composition of 1st Embodiment may further contain a suppressor compound. In this case, since the polishing rate of the silicon material portion by the polishing composition is further reduced, the polishing selectivity of the polishing composition with respect to the III-V group compound material portion is further improved.

-Polishing composition of the said embodiment may further contain well-known additives like a preservative as needed.
The polishing composition of the above embodiment may be a one-component type or a multi-component type including a two-component type.

-The polishing composition of the said embodiment may be prepared by diluting the undiluted | stock solution of polishing composition with water.
Next, examples and comparative examples of the present invention will be described.

Polishing compositions of Examples 7 to 16 , Reference Examples 1 to 6, and Comparative Example 1 were prepared by mixing colloidal silica and an oxidizing agent with water together with a suppressor compound and a pH adjuster as necessary. The details of the components in each polishing composition and the results of measuring the pH of each polishing composition are shown in Table 1.

In Table 1, “H ₂ O ₂ ” represents hydrogen peroxide, “APS” represents ammonium persulfate, and “KOH” represents potassium hydroxide.

Using the polishing compositions of Examples 7 to 16 , Reference Examples 1 to 6 and Comparative Example 1, the surfaces of the gallium arsenide blanket wafer and the tetraethyl orthosilicate (TEOS) blanket wafer were subjected to the conditions described in Table 2. The values of the polishing rate required when polishing are shown in the “GaAs polishing rate” column and the “TEOS polishing rate” column in Table 3. The value of the polishing rate is obtained by dividing the difference in thickness of the wafer before and after polishing measured by using an optical interference film thickness measuring device for the TEOS blanket wafer by the polishing time, and for the gallium arsenide blanket wafer, The difference in weight of the wafer before and after polishing was determined by dividing by the density and polishing time. Further, it is obtained by dividing the polishing rate of gallium arsenide by each of the polishing compositions of Examples 7 to 16 , Reference Examples 1 to 6 and Comparative Example 1 by the polishing rate of TEOS by the same polishing composition. The value is shown in the column “Polishing rate of GaAs / Polishing rate of TEOS” in Table 3. The TEOS polishing rate is acceptable when it is 300 Å / min or less, more preferably 200 Å / min or less, and even more preferably 100 Å / min or less. The value obtained by dividing the polishing rate of gallium arsenide by the polishing rate of TEOS is a pass level when it is 5 or more, more preferably 10 or more, and still more preferably 15 or more.

As shown in Table 3, in the case of the polishing compositions of Examples 7 to 16, the TEOS polishing rate was 100 Å / min or less, or the gallium arsenide polishing rate was divided by the TEOS polishing rate. The value was 15 or more, and a result of a level that can be satisfactorily used for the purpose of selectively polishing the group III-V compound material was obtained.

  On the other hand, in the case of the polishing composition of Comparative Example 1, the value obtained by dividing the polishing rate of gallium arsenide by the polishing rate of TEOS did not reach the acceptable level, and the III-V group compound material portion was selected. Results that could be used satisfactorily for the purpose of mechanical polishing.

Claims (5)

Use of simultaneously polishing a portion containing a group III-V compound material and a portion containing a silicon material in a polishing object having a portion containing a group III-V compound material and a portion containing a silicon material separately A portion containing a silicon material in combination with abrasive grains having an average primary particle size of 40 nm or less, an oxidizer, and a surface OH group of the portion containing the silicon material A polishing composition comprising: a suppressor compound that functions to inhibit hydrolysis of water . Use of simultaneously polishing a portion containing a group III-V compound material and a portion containing a silicon material in a polishing object having a portion containing a group III-V compound material and a portion containing a silicon material separately It is a polishing composition used in the above, and functions to inhibit hydrolysis of the part containing the silicon material by combining with the abrasive grains, the oxidizing agent, and the surface OH group of the part containing the silicon material. A polishing composition comprising a suppressor compound. The polishing composition according to claim 1 or 2 , wherein the polishing composition has a neutral pH. Using the polishing composition according to any one of claims 1 to 3, in polishing an object having a portion to separate containing moiety and silicon material containing a group III-V compound material, III- A polishing method comprising polishing a portion containing a group V compound material and a portion containing a silicon material simultaneously . Using the polishing composition according to any one of claims 1 to 3, in polishing an object having a portion to separate containing moiety and silicon material containing a group III-V compound material, III- A substrate manufacturing method comprising manufacturing a substrate by simultaneously polishing a portion containing a group V compound material and a portion containing a silicon material .