Polishing composition

Abstract

The present invention relates to a resin polishing composition for polishing a resin, comprising water, alumina abrasive grains, and an anionic surfactant having two or more benzene rings.

Description

Cross - reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2022 - 199399, and incorporates its content into the description of this application specification by reference. Technical field

[0002] The present invention relates to a polishing composition for polishing resins. Background art

[0003] Conventionally, in the manufacture of semiconductor devices, chemical mechanical polishing (hereinafter referred to as "CMP process") is carried out. For example, a semiconductor device having multilayer wirings such as an LSI has an interlayer insulating film made of resin. Moreover, in the manufacture of this semiconductor device, the CMP process is carried out to flatten the surfaces of the respective layers. Thereby, the performance of the semiconductor device is improved.

[0004] Generally, in the CMP process, a polishing slurry in which abrasive grains are dispersed in water is used. For example, in Patent Document 1, as a polishing slurry for resins, a polishing slurry containing alumina abrasive grains and alkylbenzene sulfonate as an anionic surfactant is described. According to this polishing slurry, the alkylbenzene sulfonate functions to suppress the sedimentation of the alumina abrasive grains. Thereby, the alumina abrasive grains are uniformly supplied to the polishing pad, and thus the polishing speed can be increased. Prior art documents Patent documents

[0005] Patent Document 1: WO 2019 / 176558 Technical problems to be solved by the invention

[0006] However, due to the development of highly integrated technologies in the future, the practical application of semiconductor devices with more advanced multilayer wirings is expected. Moreover, along with this, further improvement of the polishing speed in the CMP process will be sought. In addition, in this semiconductor device, resins having excellent insulation properties such as polyimide resin or epoxy resin can be used. However, since these resins are relatively hard, they may become an obstacle to the improvement of the polishing speed. Summary of the invention

[0007] In view of the above - mentioned circumstances, the problem of the present invention is to provide a polishing composition that is excellent in improving the polishing speed of resins. Technical solutions for solving the problems

[0008] A polishing composition according to an embodiment of the present invention is used for polishing resins, and contains water, alumina abrasive grains, and an anionic surfactant, wherein the anionic surfactant has two or more benzene rings.

[0009] In a polishing composition according to an embodiment of the present invention, the anionic surfactant has more than three benzene rings.

[0010] In a polishing composition according to an embodiment of the present invention, based on the total mass of the polishing composition, the content of the anionic surfactant is 0.2% by mass or more. Preferably, the ratio of the mass of the anionic surfactant to the mass of the alumina abrasive grains is 1:0.1 or more.

[0011] The pH of the polishing composition according to an embodiment of the present invention is 2 to 8. Detailed Embodiments

[0012] Hereinafter, the polishing composition according to the embodiment of the present invention will be described.

[0013] The polishing composition is a polishing composition for polishing a resin, and includes water, alumina abrasive grains, and an anionic surfactant. In addition, the polishing composition may further include a pH adjuster and an antifoaming agent. The polishing composition may also be a polishing slurry in which alumina abrasive grains are dispersed in water.

[0014] The alumina abrasive grains may also be particles composed of α-alumina. In addition, the alumina abrasive grains may also be particles composed of γ-alumina, δ-alumina, θ-alumina, η-alumina, κ-alumina, χ-alumina, etc. In addition, the alumina abrasive grains may be composed of only one of these alumina particles, or may be composed of two or more.

[0015] The median particle size of the alumina abrasive grains is 0.05 to 1 μm. The median particle size is preferably 0.1 to 0.5 μm. The median particle size can be measured as follows. That is, using a laser diffraction / scattering particle size distribution measuring device LA-920 (manufactured by Horiba, Ltd.), the volume particle size distribution is obtained by the laser diffraction / scattering method. Then, the particle size at which the cumulative volume frequency of the obtained volume particle size distribution is 50% is taken as the median particle size of the alumina abrasive grains.

[0016] Based on the total mass of the polishing composition, the content of the alumina abrasive grains is preferably 0.3% by mass or more, more preferably 0.5% by mass or more, and still more preferably 1.0% by mass or more. In addition, the content of the alumina abrasive grains is preferably 10% by mass or less, more preferably 5.0% by mass or less, and still more preferably 3.0% by mass or less.

[0017] The anionic surfactant has a hydrophobic group composed of two or more benzene rings and a sulfate ester as a hydrophilic group.

[0018] The hydrophobic group composed of two or more benzene rings can be a group having a structure in which two benzene rings are connected via one carbon atom, such as diphenylmethane, or can be composed of a group having a structure in which two benzene rings are directly bonded by a single bond, such as biphenyl, or can be composed of a group having a structure in which two benzene rings share a carbon-carbon bond, such as naphthalene or anthracene, or can be composed of a structure in which two benzene rings are connected via an ether bond (including a thioether), such as phenyl ether.

[0019] In addition to the sulfate ester, the hydrophilic group can also be a sulfonic acid group, a carboxyl group, or a phosphate ester. From the viewpoint of improving the polishing rate, the hydrophilic group is preferably a sulfate ester or a sulfonic acid group.

[0020] The anionic surfactant can also have a structure in which the hydrophobic group and the hydrophilic group are connected via a hydrocarbon group. The hydrocarbon group can have a structure composed of a saturated carbon chain, or can have a structure composed of a saturated carbon chain bonded with an aryl group such as a phenyl group, or can have a structure composed of an unsaturated carbon chain, or can have a structure composed of an unsaturated carbon chain bonded with an aryl group such as a phenyl group. For example, the anionic surfactant can also have the hydrophobic group and the hydrophilic group, wherein the hydrophobic group is bonded to the carbon at one end of the side of the alkylene group as the hydrocarbon group; the hydrophilic group is bonded to the carbon at the other end of the alkylene group.

[0021] More specifically, the anionic surfactant can also have a structure represented by the following chemical formula (1). In Chemical Formula (1), I is the substitution degree of the styrene group in the phenyl group. I is 1 or more, more preferably 2 or more. In other words, the hydrophobic group in Chemical Formula (1) has two or more benzene rings, preferably three or more benzene rings. The number of benzene rings in the hydrophobic group in Chemical Formula (1) is six or less, preferably four or less. m represents the polymerization degree of propylene oxide (PO) in the alkylene group. m is preferably 2 or more. In addition, m is preferably 10 or less. n represents the polymerization degree of ethylene oxide (EO) in the alkyl group. n is preferably 5 or more, more preferably 10 or more, and further preferably 20 or more. In addition, n is preferably 40 or less, and further preferably 30 or less. In addition, in the alkylene group, a chain composed only of PO and a chain composed only of EO can be connected, or PO and EO can be randomly connected. As the anionic surfactant having the structure of Chemical Formula (1), for example, polyoxyalkylene polystyryl phenyl ether sulfate salt, polyoxyalkylene polystyryl phenyl ether phosphate salt, etc. can be cited.

Chemical Formula 1

[0022] As the anionic surfactant, a surfactant having a hydrophobic group composed of diphenyl ether and a sulfonic acid group as a hydrophilic group is also applicable. As such an anionic surfactant, for example, alkyl diphenyl ether disulfonate can be cited.

[0023] In addition, as the anionic surfactant, a surfactant having a hydrophobic group composed of naphthalene and a sulfonic acid group as a hydrophilic group is also applicable. As such anionic surfactants, for example, naphthalene sulfonate, naphthalene disulfonate, naphthalene trisulfonate, and butyl naphthalene sulfonate can be cited. In addition, it can also be a salt of a naphthalene sulfonic acid formalin condensate such as poly naphthalene methyl sulfonate. Among these, alkyl naphthalene sulfonates such as butyl naphthalene sulfonate are preferred.

[0024] In addition, as the anionic surfactant, it may also have the hydrophobic group and the hydrophilic group, wherein the hydrophobic group is bonded to the vinyl carbon at the terminal side of the styryl group as the hydrocarbon group; the hydrophilic group is bonded to the benzene ring of the styryl group. As such anionic surfactant, for example, sodium 4,4'-bis(2-sulfonatostyryl)biphenyl can be cited.

[0025] The anionic surfactant can be an alkali metal salt such as sodium or potassium, and can also be an ammonium salt in which ammonia is ionically bonded to the hydrophilic group, and can also be an amine salt in which an organic amine is ionically bonded to the hydrophilic group. From the viewpoint of improving the polishing rate, an alkali metal salt is preferred.

[0026] Relative to the total mass of the polishing composition, the content of the anionic surfactant is preferably 0.1% by mass or more, more preferably 0.2% by mass or more. Thereby, the polishing rate can be sufficiently increased. In addition, the content of the anionic surfactant is preferably 1.0% by mass or less. Thereby, foaming during polishing can be suppressed.

[0027] In addition, the ratio of the mass of the anionic surfactant to the mass of the alumina abrasive grains (the mass of the alumina abrasive grains: the mass of the anionic surfactant) is preferably 1:0.1 or more, more preferably 1:0.2 or more, and further preferably 1:0.3 or more.

[0028] The polishing composition may further contain the pH adjuster so that the pH value is 2 to 8. As the pH adjuster, inorganic acids such as nitric acid, sulfuric acid, boric acid, carbonic acid, and phosphoric acid, and inorganic base compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate are preferred. In addition, in terms of adjusting the pH to 2 to 8, as the pH adjuster, carboxylic acids such as formic acid, acetic acid, oxalic acid, citric acid, malonic acid, tartaric acid, maleic acid, and malic acid; amino acids such as glycine and arginine; and amine compounds such as ammonia, primary amines, secondary amines, tertiary amines, quaternary ammonium salts and their hydroxides, and heterocyclic amines are also preferred.

[0029] The abrasive composition can be suitably used for abrasion of an object to be abraded made of a polyimide resin, a polybenzoxazole resin, an epoxy resin, or a benzocyclobutene resin. More specifically, the abrasive composition can be suitably used for abrasion of a resin layer such as an interlayer insulating film of a semiconductor device and made of any of the above resins. The polyimide resin is preferably an aromatic polyimide resin having a benzene ring. In addition, the epoxy resin preferably has a benzene ring such as a copolymer of a bisphenol compound and epichlorohydrin. Thus, the interaction with the hydrophobic group of the anionic surfactant is enhanced, and further, the affinity between the object to be abraded and the alumina abrasive grains can be improved. In addition, the resin constituting the object to be abraded is not limited to the above resins. For example, compared with a conventional abrasive composition, the abrasive composition is excellent in increasing the abrasion rate, and thus can also be used for abrasion of an object to be abraded made of a resin having a higher hardness than the above resin. In addition, the resin can be a resin having the same hardness as the above resin, or can be a resin having a relatively low hardness.

[0030] According to the abrasive composition, it is considered that the hydrophilic group of the anionic surfactant acts in a manner of adsorbing to the alumina abrasive grains, and the hydrophobic group of the anionic surfactant interacts with the resin constituting the object to be abraded in a mutually attracting manner. Moreover, it is considered that the affinity between the alumina abrasive grains and the resin constituting the object to be abraded is improved thereby, and the abrasion rate is increased. In terms of enhancing the interaction between the hydrophobic group and the resin of the object to be abraded, it is preferable that the hydrophobic group has three or more benzene rings and the resin has an aromatic ring such as a benzene ring.

[0031] In addition, since the pH of the abrasive composition is 2 to 8, the anionic surfactant (especially the surfactant represented by the chemical formula (1)) is easily adsorbed to the alumina abrasive grains showing a positive ζ potential. It is considered that the abrasion rate is increased thereby. From this viewpoint, the pH of the abrasive composition is preferably 3 to 7.

[0032] As described above, although the embodiments are shown as examples, the abrasive composition according to the present invention is not limited to the constitution of the embodiments. In addition, the abrasive composition according to the present invention is not limited by the above effects. The abrasive composition of the present invention can be variously modified without departing from the gist of the present invention.

[0033] For example, the abrasive composition of the present invention may further contain an oxidizing agent such as a hydrogen peroxide solution, a complexing agent such as glycine, and an antifoaming agent such as a silicone emulsion as other additives. In addition, a preservative, a mildew-proof agent, etc. may also be contained.

[0034] In addition, although the polishing composition having a pH of 2 to 8 is illustrated as a preferred embodiment above, in addition to this, a pH of 5 or more and 11 or less or a pH of 8 or more and 11 or less can also sufficiently increase the polishing rate.

[0035] In addition, as the object to be polished, it is not limited to the material constituting the semiconductor device, and can also be suitably used for polishing printed circuit boards, module substrates, packaging substrates, etc. containing resin.

[0036] The matters disclosed in this specification include the following. (1) A polishing composition for polishing resin, comprising water, alumina abrasive grains, and an anionic surfactant, wherein the anionic surfactant has two or more benzene rings. (2) The polishing composition as described in (1) above, wherein the anionic surfactant has three or more benzene rings. (3) The polishing composition as described in (1) or (2) above, wherein the content of the anionic surfactant is 0.2% by mass or more based on the total mass of the polishing composition. (4) The polishing composition as described in any one of (1) to (3) above, wherein the ratio of the mass of the anionic surfactant to the mass of the alumina abrasive grains is 1:0.1 or more. (5) The polishing composition as described in any one of (1) to (4) above, having a pH of 2 to 8.

Examples

[0037] Hereinafter, the present invention will be further described by way of examples, but the present invention is not limited to these examples.

[0038]

Evaluation 1 of the number of benzene rings of the anionic surfactant

[0039] (Polishing conditions) Polishing apparatus: SH24 (SpeedFam) Polishing pad: IC1000 (manufactured by NITTA DuPont), a polishing pad having a polishing surface made of a resin foam (polyurethane resin foam) Polishing load: 3 psi Table speed: 90 rpm Head speed: 89rpm Grinding time: 1min Slurry flow rate: 150mL / min Object to be polished: Wafer with polyimide resin film (PI2727 manufactured by Hitachi Chemical Co., Ltd.)

[0040]

Table 1

[0041] From the evaluation results in Table 1, it can be seen that as the number of benzene rings of the anionic surfactant increases, the polishing rate tends to increase. 1 H-NMR, 13 C-NMR analysis of the polyoxyalkylene polystyrene phenyl ether sodium sulfate in Table 1 When analyzed by Tetrasulfate (Estrusulfate), in the chemical formula (1), I=2.7, m=2.4, and n=26. (LC / MS analysis conditions) LC device: manufactured by Waters, ACQUITY UPLC MS device: Waters, SYNAPT G2-S Column: Unison UK-C8 manufactured by Imtakt (2 mm inner diameter, 50 mm length) Column temperature: 40°C Mobile phase A: 10 mM ammonium formate in water Mobile phase B: acetonitrile %B: 25(0min)→100(10~15min) Flow rate: 0.4mL / min Detector: PDA, MS Detection wavelength: 254nm Ionization method, polarity: ESI method, negative Determination mass range: m / z 50~2000 Sample injection volume: 0.2μL (MS) or 0.5μL (MS / MS) Sample preparation: Sample 20 mg / methanol 10 mL (NMR analysis conditions) Device: AVANCE NEO 600 manufactured by Bruker Japan Determination solvent: deuterated methanol, sample about 100 mg / mL Internal reference substance: TMS (0ppm)

[0042]

Evaluation 1 of the content of anionic surfactant

[0043]

Table 2

[0044] As shown in Table 2, it can be seen that the larger the content of sodium polyoxyalkylene polystyrylphenyl ether sulfate, the more the polishing rate tends to increase.

[0045]

Evaluation 2 of the content of anionic surfactant

[0046]

Table 3

[0047] From the evaluation results in Table 3, it can be known that the mass ratio of sodium polyoxyalkylene polystyrylphenyl ether sulfate to alumina abrasive grains is preferably 1:0.1 or more.

[0048]

Evaluation of the effects of complexing agent and defoaming agent

[0049]

Table 4

[0050] As shown in Table 4, no inhibitory effects due to the complexing agent and the defoaming agent were observed.

[0051]

Evaluation of pH

[0052]

Table 5

[0053] As shown in Table 5, it can be understood that the abrasive slurry with a pH of 2 to 8 is more excellent in improving the polishing rate.

[0054]

Evaluation of the degree of polymerization of anionic surfactants

[0055]

Table 6

[0056] As shown in Table 6, it can be seen that the degree of polymerization in the alkylene group of the anionic surfactant affects the polishing rate.

[0057]

Evaluation of abrasive grains

[0058]

Table 7

[0059] From the evaluation results in Tables 1 to 7, the synergistic effect brought about by alumina abrasive grains and polyoxyalkylene polystyryl phenyl ether sulfate sodium can be seen. On the other hand, as shown in Table 7, for abrasive grains other than alumina abrasive grains, no synergistic effect with polyoxyalkylene polystyryl phenyl ether sulfate sodium was seen.

[0060]

Evaluation of the number of benzene rings of anionic surfactants 2

[0061]

Table 8

[0062] From the evaluation results in Table 8, it can also be seen that as the number of benzene rings of the anionic surfactant increases, the polishing rate shows an increasing tendency.

Claims

1. A polishing composition for polishing a resin, comprising water, alumina abrasive grains, and an anionic surfactant, wherein the anionic surfactant has two or more benzene rings.

2. The abrasive composition according to claim 1, wherein, The anionic surfactant has three or more benzene rings.

3. The abrasive composition according to claim 1 or 2, wherein, Based on the total mass of the polishing composition, the content of the anionic surfactant is 0.2% by mass or more.

4. The abrasive composition according to claim 3, wherein, The mass ratio of the anionic surfactant to the mass of the alumina abrasive grains is 1:0.1 or more.

5. The polishing composition according to claim 1 or 2, having a pH of 2 to 8.

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