JP4060239B2 - Manufacturing method of polyolefin resin substrate storage container - Google Patents

Description

【００２３】
本発明の基板収納容器によれば、ポリオレフィン系樹脂に含まれるハロゲン成分に起因する成形機や金型等の腐食、収納基板の不具合、歩留りの低下を防止すると共に、金属成分による収納基板の汚染を防止して、各種基板を清浄な状態で搬送、保管することができる。
【図面の簡単な説明】
【図１】実施例・比較例で作製した基板収納容器の構成を示す概略断面図である。
【符号の説明】
１…蓋
２…クッション
３…キャリア
４…ガスケット
５…本体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate storage container made of a polyolefin resin composition and a method for producing the same. More specifically, the present invention relates to a polyolefin resin substrate storage container and a method for manufacturing the same, which can transport and store various substrates, particularly electronic device substrates such as semiconductor silicon wafers and liquid crystal devices, in a clean state.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, when various substrates such as silicon wafers are transported and stored, a substrate storage container for storing the substrate is used to prevent the substrate from being contaminated or damaged. As a constituent material of the substrate storage container, as a result of comprehensive consideration of various factors such as lightness, cleanliness, productivity, and cost, polyolefin-based resins, particularly polypropylene resins, are frequently used.
In recent years, with respect to the substrate storage container, regardless of whether the constituent material is an organic material or an inorganic material, with the progress of miniaturization and high integration of various semiconductor devices, it has become more sophisticated than ever. There is a growing demand to prevent substrate contamination at the level.
[0003]
Polyolefin resin, which is widely used as a material for substrate storage containers, is manufactured using a Ziegler catalyst containing TiCl ₃ or the like as a main component. Polyolefin resin manufactured using this catalyst has its manufacturing method. Although the content varies depending on the type of catalyst, the halogen component (mainly chlorine) of the Ziegler catalyst remains as a catalyst residue.
When the substrate storage container is molded using the polyolefin resin in which the halogen component remains as it is, hydrogen halide is generated by the heating performed at the time of molding, and the generated hydrogen halide corrodes the molding machine or the mold. There was a problem of causing it.
In addition, when a substrate storage container in which a halogen component remains is used, the substrate is contaminated by the halogen component, and as a result, there is a problem that the substrate malfunctions and the yield decreases.
[0004]
As a method for solving these problems, a method of suppressing the generation of hydrogen halide by adding a halogen scavenger to a polyolefin resin containing a halogen component is generally known. For example, as a method of suppressing the generation of hydrogen halide and preventing corrosion of molding machines and molds due to hydrogen halide, basic compounds such as alkaline earth metal oxides and hydroxides are added to polyolefin resins. A method of blending (Patent Document 1), a method of blending an oxide or hydroxide of aluminum (Patent Document 2), and a method of blending a compound containing magnesium, aluminum, calcium, zinc, etc. (Patent Document 3) are disclosed. Has been.
In addition, a polyolefin resin composition that effectively prevents generation of rust due to a halogen component and is suitable for uses such as a substrate storage container has been proposed. For example, a polyolefin resin composition (Patent Document 4) in which hexahydrophthalic acid ester and a hydrotalcite compound are blended in a polyolefin resin, and a wafer made of a resin material in which a stearate, a hydrotalcite agent, etc. are blended in a polypropylene resin. A storage container (Patent Document 5) is disclosed.
[0005]
Prior art document information relating to the invention of this application includes the following.
[Patent Document 1]
Japanese Patent Publication No.33-3541 [Patent Document 2]
Japanese Patent Publication No.49-3947 [Patent Document 3]
JP 52-49258 A [Patent Document 4]
Japanese Patent Laid-Open No. 6-1000073 [Patent Document 5]
Japanese Patent Laid-Open No. 8-250581
[Problems to be solved by the invention]
However, although the method for prescribing the halogen scavenger described above is effective for preventing corrosion of molding machines, molds, etc., and preventing contamination of the storage substrate by halogen components, any halogen scavenger can be used for various alkalis. Since it contains earth metals, aluminum, calcium, magnesium, zinc, etc., there is a problem that the storage substrate is contaminated by the metal component contained in the halogen scavenger when the substrate storage container and the storage substrate are rubbed or worn. It was.
In addition, regarding the amount of halogen scavenger added, the amount to be added to prevent contamination with halogen components largely depends on empirical prescriptions. There is also a problem that the storage substrate is contaminated by the metal component.
Therefore, the present invention prevents corrosion of a molding machine or a mold due to a halogen component contained in a polyolefin resin, a malfunction of a storage substrate, a decrease in yield, and prevents contamination of the storage substrate with a metal component. It is an object of the present invention to provide a substrate storage container that can transport and store various substrates in a clean state and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventor selects an epoxy compound that does not substantially contain a metal component as the halogen scavenger, and adds a predetermined amount of this epoxy compound to the polyolefin resin. Thus, the present inventors have found that the above problems can be solved, and have completed the present invention based on such knowledge.
That is, the substrate storage container of the present invention is a substrate storage container made of a polyolefin resin composition, wherein the polyolefin resin composition contains an epoxy compound that does not substantially contain a metal component, and The amount of chlorine ions collected when the polyolefin resin composition is heated in a helium stream at 220 ° C. for 60 minutes is 30 ppb or less per weight of the polyolefin resin composition.
The substrate storage container manufacturing method of the present invention is a method for manufacturing a substrate storage container made of a polyolefin resin composition, wherein the polyolefin resin is compounded with an epoxy compound that does not substantially contain a metal component. After preparing the composition, this polyolefin resin composition was heated in a helium stream at 220 ° C. for 60 minutes to measure the amount of chlorine ions collected, and the chlorine ion amount was 30 ppb per weight of the polyolefin resin composition. In the case of exceeding, the compounding ratio of the epoxy compound in the polyolefin resin composition is adjusted to have the step of adjusting the chlorine ion amount to 30 ppb or less.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As described above, the substrate storage container of the present invention is composed of a polyolefin resin composition containing a polyolefin resin and an epoxy compound as essential components.
The type of the polyolefin resin is not particularly limited, but considering the purpose of the present invention, polyolefin resins containing a halogen component (mainly chlorine) are targeted, and usually they use a Ziegler catalyst. It was obtained by polymerization. The polyolefin resin includes both a homopolymer that is a single olefin polymer, a copolymer that is two or more olefin polymers, a mixture thereof, and the like. Representative examples of the polyolefin resin include polypropylene resin, polyethylene resin, propylene-ethylene block copolymer, propylene-ethylene random copolymer, and the like.
The polyolefin-based resin may be produced by any method. For example, the type of polymerization method such as bulk polymerization, solvent polymerization, gas phase polymerization, and a cleaning process for removing catalyst residues. It doesn't matter whether it exists or not.
[0009]
The epoxy-type compound which comprises a polyolefin-type resin composition should just contain a metal component substantially and has one or more epoxy groups. Examples of the epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexylcarboxylate. 2,3-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, 4- (3,4-epoxy-5-methylcyclohexyl) butyl ester of 3,4-epoxycyclohexanecarboxylic acid, 3,4-epoxycyclohexyl Alicyclic epoxy compounds such as ethylene oxide and 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxyhexene carboxylate; aromatic epoxy compounds such as bisphenol A diglycidyl ether and diglycidyl ester of phthalic acid Aliphatic compounds such as butadiene diepoxide; butanediol (bis - glycidyl ether) aliphatic bis (epoxy ether), such as, epoxidized soybean oil, epoxidized castor oil, may be mentioned epoxidized linseed oil.
Of these epoxy compounds, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxyhexene carboxylate and epoxidized soybean oil are particularly preferred in consideration of halogen scavenging ability and cost.
[0010]
Since the epoxy compound used as a halogen scavenger does not substantially contain a metal component in its constituent molecule, the storage substrate and the substrate storage container are rubbed and worn during storage and transport of the storage substrate. Thus, it is possible to completely prevent the conventional problem that the metal component in the halogen scavenger contaminates the storage substrate.
[0011]
The amount of the epoxy compound should correspond to the amount of the halogen component (mainly chlorine) that is essentially the residue of the Ziegler catalyst contained in the polyolefin resin used, and stoichiometrically, If there is 1 molar equivalent of an epoxy group that captures 1 mole equivalent of the halogen component contained, the capture reaction of the halogen component with the epoxy compound is completed.
However, in practice, the halogen component in the polyolefin resin and the epoxy group in the epoxy compound react one-on-one and the halogen component is captured in terms of reaction efficiency. It is hard to happen. Therefore, the conventional halogen scavenger is generally compounded in an amount that allows for an empirical safety factor, for example, stoichiometrically, several times to several hundred times the theoretical amount.
By the way, the halogen component contained in the polyolefin resin is the type of catalyst or deactivator used in the production of the polyolefin resin, the type of deashing / washing method, the type of polymerization, and the solvent used in the polymerization. Depending on the presence / absence / type, etc., the form of the halogen component that finally remains and the degree of its activity, that is, the amount of the halogen component that is generated at the time of molding and after becoming a storage container, vary as a result.
On the other hand, epoxy compounds that capture halogen components also have different compatibility and mobility in polyolefin resins due to differences in properties such as molecular weight, melting point, and vapor pressure depending on the type, resulting in halogen components. It is thought that the capture ability of is different.
[0012]
Thus, the residual halogen component in the polyolefin-based resin and the properties of the epoxy-based compound differ depending on the type and the like. Therefore, the addition amount of the epoxy compound should originally be added in an optimum amount depending on the combination with the residual halogen component in the polyolefin resin. In particular, when an excessive amount of an epoxy compound is added to the substrate storage container of the present invention, the epoxy compound may cause secondary contamination of the storage substrate. Therefore, it is important to formulate the necessary minimum amount of the epoxy compound.
As a result of intensive investigations in consideration of such points, the present inventor has found that contamination by halogen components, regardless of the amount and characteristics of the halogen components contained in the polyolefin resin to be used and the combination of epoxy compounds to be added. The addition amount of the epoxy-type compound which can be prevented was discovered.
That is, the amount of the epoxy compound added is such that the amount of chlorine ions collected when the polyolefin resin composition is heated at 220 ° C. for 60 minutes in a helium stream is 30 ppb or less per weight of the polyolefin resin composition. Accordingly, it is possible to prevent corrosion of a molding machine or a mold due to a halogen component contained in the polyolefin-based resin, a malfunction of the storage substrate, a decrease in yield, and the like.
In addition, in order to prevent secondary contamination of the storage substrate by excessive addition of the epoxy compound, the addition amount of the epoxy compound is collected when the polyolefin resin composition is heated at 220 ° C. for 60 minutes in a helium stream. The total amount of volatile organic substances is preferably 20 ppm or less.
In addition, the above-mentioned chlorine ion amount can be measured by fluorescent X-rays.
[0013]
The polyolefin-based resin composition used in the present invention includes an antioxidant, an ultraviolet ray inhibitor, a light stabilizer, a nucleating agent, a flame retardant, a lubricant, an antistatic agent, a heat stabilizer, and a colorant as necessary. Additives such as fillers can be added without departing from the object of the present invention.
[0014]
In the method for producing a substrate storage container of the present invention, a polyolefin resin composition is prepared by blending an epoxy compound containing substantially no metal component with a polyolefin resin, and then the polyolefin resin composition is placed in a helium stream. Measure the amount of chlorine ions collected by heating at 220 ° C for 60 minutes, and if the amount of chlorine ions exceeds 30 ppb per weight of the polyolefin resin composition, mix the epoxy compound in the polyolefin resin composition The method is not particularly limited as long as it has a step of adjusting the ratio so that the chlorine ion amount is 30 ppb or less. For example, the polyolefin resin composition that has undergone the above steps is premixed with a Henschel mixer or the like, and the resulting mixture is pelletized with an extruder to prepare pellets, and then the pellets are injection molded under general conditions. The substrate storage container of the present invention is produced.
In the production method of the present invention, when the chlorine ion amount is 30 ppb or less per weight of the polyolefin resin composition, it is not particularly necessary to change the mixing ratio of the epoxy compound in the polyolefin resin composition. As long as the chlorine ion amount is maintained at 30 ppb or less, the blending ratio of the epoxy compound can be changed.
In addition, in order to reduce the possibility that the storage substrate is contaminated by volatile organic components generated from the polyolefin resin, for example, in the manufacturing process of pellets of the polyolefin resin composition, in the hopper part or cylinder part of the extruder Vacuum deaeration, heat drying of pellets after pellet granulation, drying treatment of molded products formed using pellets, and the like may be performed as necessary.
[0015]
【Example】
EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.
[0016]
Example 1
For 100 parts by weight of the homopolypropylene resin polymerized by the melting method, as a halogen-trapping agent, celcycloside 2021 (3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxyhexene carboxy, which is an alicyclic epoxy compound, is used. Rate / trade name / manufactured by Daicel Chemical) 500 ppm and Irganox ^{10 10} (trade name / manufactured by Ciba Geigy) 100 ppm as an antioxidant, dry blended with a Henschel mixer, heated and kneaded with a single screw extruder, polypropylene A pellet of the resin composition was obtained.
The amount of chlorine contained in this polypropylene resin composition was 5 ppm as a result of analysis by fluorescent X-ray, and thus ((5 × 10 ⁻⁶ ) /35.5) = 1.4 × 10 ⁻⁷ equivalent / g. .
On the other hand, the added ceroxide 2021 has two epoxy groups in one molecule, and its molecular weight is 252. Therefore, {(500 × 10 ⁻⁶ ) / 252} × 2 = 4.0 × 10 ⁻⁶ equivalent / g. Therefore, Celoxide 2021 is added in an amount of (4.0 × 10 ⁻⁶ ) / (1.4 × 10 ⁻⁷ ) = 29 times the amount of chlorine contained in the polypropylene resin composition.
Next, 20 g of the above pellets are placed in an Erlenmeyer flask, heated in a helium stream at 220 ° C. for 60 minutes, the generated chlorine ions are collected with pure water, and the amount of chlorine ions (hereinafter referred to as the amount of chlorine generated by heating) is measured by ion chromatography. ) Was determined to be 8 ppb per weight of the polypropylene resin composition.
Next, using the above pellets, as shown in FIG. 1, among the substrate storage container composed of the lid 1, the cushion 2, the carrier 3, the gasket 4, and the main body 5, each component excluding the gasket 4 is formed by injection molding. Produced. This substrate storage container can store 25 silicon wafers having a diameter of 200 mm. As for the gasket 4, in the following evaluation, in order to remove the influence of the chlorine component contained other than the polypropylene resin, a gasket 4 obtained by separately molding with a polyester elastomer material not containing the chlorine component was used.
After inserting one cleaned silicon wafer into the center slot of the carrier, the substrate storage container was sealed and left in a clean room for 10 days. Thereafter, the wafer was taken out, washed with pure water, and the chlorine ion concentration in the cleaning solution was measured by ion chromatography, whereby the amount of chlorine ions generated on the wafer was quantified. As a result, the amount of chlorine ions generated by heating was 8 ppb.
Then, by calculating the difference between the amount of chlorine ions generated by heating and the amount of chlorine ions adhering to the wafer before storage measured in advance, the amount of increase in chlorine ions after being left in the substrate storage container was calculated. The obtained increase amount of chlorine ions was 25 ng, which is well below 200 ng which is a standard for chlorine ion contamination.
Next, after 25 silicone wafers are fully filled in the above-mentioned substrate storage container, it is installed in a vibration tester and 1 cycle: amplitude 0.75 mm (vertical direction), excitation frequency 10 Hz → 55 Hz → 10 Hz in 60 seconds After applying 10 cycles of vibration under the condition of sweeping, the wafer was taken out, focusing on the periphery of the wafer outer periphery in contact with the carrier, with SEM (scanning electron microscope) and EPMA (electron probe microanalysis), The presence or absence of particles was examined, and the component analysis of the particles was performed. As a result, no generation of particles due to the polypropylene resin composition was observed, and no metal component was detected.
In addition, the polypropylene resin composition is scraped from a part of the carrier, and the generated volatile organic components are collected with liquid nitrogen and TENAX scavenger in a helium stream at 80 ° C for 60 minutes. Thus, the total amount of volatile organic substances generated was measured using n-decane as a standard, and it was 7 ppm in terms of the weight of the polypropylene resin composition. These results are summarized in Table 1.
[0017]
(Example 2)
As an epoxy compound, 100 ppm by weight of a homopolypropylene resin polymerized by a gas phase method was used as an epoxidized soybean oil, Adeka Sizer O-130P (trade name / Asahi Denka Kogyo Co., Ltd.) 1000 ppm, and Example 1 0.01 parts by weight of an antioxidant was added, and a pellet of the polypropylene resin composition was obtained in the same manner as in Example 1 to prepare a substrate storage container.
The amount of chlorine contained in this polypropylene resin composition was 10 ppm as a result of analysis by fluorescent X-ray, and therefore, ((10 × 10 ⁻⁶ ) /35.5) = 2.8 × 10 ⁻⁷ equivalent / g. .
On the other hand, the added epoxidized soybean oil has 4 epoxy groups per mole from the number of epoxy groups contained in oleic acid and linoleic acid, and their constituent ratio, and its molecular weight is 1000. {(1000 × 10 ⁻⁶ ) / 1000} × 4 = 4.0 × 10 ⁻⁶ equivalent / g Therefore, the epoxy compound is added in an amount of (4.0 × 10 ⁻⁶ ) / (2.8 × 10 ⁻⁷ ) = 14 times the amount of chlorine contained in the polypropylene resin composition.
And as a result of performing the same measurement as Example 1, the amount of chlorine ions generated by heating was 18 ppb, and the increase amount of chlorine ions adhering to the silicon wafer was 45 ng.
Further, no generation of particles was observed on the wafer after the vibration test, and no metal component was detected. Furthermore, the total amount of volatile organic substances in terms of weight of the polypropylene resin composition was 14 ppm. These results are summarized in Table 1.
[0018]
(Example 3)
Except for adding 10,000 ppm of Celoxide 2021 to 100 parts by weight of the polypropylene resin used in Example 1, pellets of the polypropylene resin composition were obtained in the same manner as in Example 1 to prepare a substrate storage container. In this case, the added ceroxide 2021 is {(10000 × 10 ⁻⁶ ) / 252} × 2 = 80 × 10 ⁻⁶ equivalent / g. Therefore, the ceroxide 2021 is based on the chlorine content in the polypropylene resin composition. Thus, (80 × 10 ⁻⁶ ) / (1.4 × 10 ⁻⁷ ) = 570 times the amount was added.
As a result of performing the same measurement as in Example 1, the amount of chlorine ions generated by heating was 5 ppb, and the amount of increase in chlorine ions adhering to the silicon wafer was 18 ng, which was much less than 200 ng, which is a standard for chlorine ion contamination.
Further, no generation of particles was observed on the wafer after the vibration test, and no metal component was detected. However, the total amount of volatile organic substances in terms of the weight of the polypropylene resin composition was as high as 45 ppm. It was not preferable compared to. Therefore, it is desirable that the halogen scavenger is added as little as possible within the range where the amount of chlorine generated by heating is 30 ppb or less. These results are summarized in Table 1.
[0019]
Example 4
Except that 1000 ppm of Celoxide 2021 was added to 100 parts by weight of the polypropylene resin used in Example 1, pellets of the polypropylene resin composition were obtained in the same manner as in Example 1 to prepare a substrate storage container. In this case, the added ceroxide 2021 is {(1000 × 10 ⁻⁶ ) / 252} × 2 = 8 × 10 ⁻⁶ eq / g. Therefore, the ceroxide 2021 is based on the chlorine content in the polypropylene resin composition. Thus, (8 × 10 ⁻⁶ ) / (1.4 × 10 ⁻⁷ ) = 57 times the amount was added.
As a result of performing the same measurement as in Example 1, the amount of chlorine ions generated by heating was 3 ppb, and the amount of increase in chlorine ions adhering to the silicon wafer was 12 ng, which was much less than 200 ng, which is a standard for chlorine ion contamination.
The total amount of volatile organic substances was 18 ppm, which was below 20 ppm, which is a standard for organic contamination. These results are summarized in Table 1.
[0020]
(Comparative Example 1)
Except that 50 ppm of Celoxide 2021 was added to 100 parts by weight of the polypropylene resin used in Example 1, pellets of the polypropylene resin composition were obtained in the same manner as in Example 1 to prepare a substrate storage container. In this case, the added ceroxide 2021 is {(50 × 10 ⁻⁶ ) / 252} × 2 = 4.0 × 10 ⁻⁷ equivalent / g. Therefore, the ceroxide 2021 is based on the amount of chlorine contained in the polypropylene resin composition. Thus, (4.0 × 10 ⁻⁷ ) / (1.4 × 10 ⁻⁷ ) ≈3 times the amount was added.
As a result of performing the same measurement as in Example 1, the amount of chlorine ions generated by heating was 48 ppb, and the amount of increase in chlorine ions adhering to the silicon wafer was 320 ng, which greatly exceeded 200 ng, which is a standard for chlorine ion contamination. .
This result seems to be because the addition amount of ceroxide 2021, which is an epoxy compound, is about three times as small as the amount of chlorine contained in the polypropylene resin composition, and the ratio of the epoxy compound was extremely insufficient.
Further, no generation of particles was observed on the wafer after the vibration test, and no metal component was detected. Furthermore, the total amount of volatile organic substances in terms of weight of the polypropylene resin composition was 3 ppm. These results are summarized in Table 1.
[0021]
(Comparative Example 2)
Except that 500 ppm of calcium stearate was added to 100 parts by weight of the polypropylene resin used in Example 1, pellets of the polypropylene resin composition were obtained in the same manner as in Example 1 to prepare a substrate storage container. In the reaction formula, calcium stearate is substituted by calcium and chlorine to capture 2 molar equivalents of chlorine per mole, so that the added calcium stearate is {(500 × 10 ⁻⁶ ) / 606} / (1.4 × 10 ⁻⁷ ) = 6 times the amount.
As a result of performing the same measurement as in Example 1, the amount of chlorine ions generated by heating was 10 ppb, and the amount of increase in chlorine ions adhering to the silicon wafer was 52 ng.
However, as a result of performing a vibration test similar to that of Example 1, particles were observed on a part of the outer periphery of the wafer in contact with the carrier, and as a result of elemental analysis, contamination with calcium, which is a component of calcium stearate, was observed. It was. Further, the total amount of volatile organic substances in terms of weight of the polypropylene resin composition was 8 ppm. These results are summarized in Table 1.
[0022]
[Table 1]

[0023]
According to the substrate storage container of the present invention, the corrosion of the molding machine or the mold due to the halogen component contained in the polyolefin-based resin, the failure of the storage substrate, the decrease in yield, and the contamination of the storage substrate by the metal component are prevented. In this way, various substrates can be transported and stored in a clean state.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a configuration of a substrate storage container produced in Examples and Comparative Examples.
[Explanation of symbols]
1 ... Lid 2 ... Cushion 3 ... Carrier 4 ... Gasket 5 ... Body

Claims (1)

In a method for manufacturing a substrate storage container made of a polyolefin resin composition, a polyolefin resin composition is prepared by blending an epoxy compound that does not contain a metal component with a polyolefin resin, and then the polyolefin resin composition is mixed with a helium gas stream. When the amount of chlorine ions collected by heating at 220 ° C. for 60 minutes is measured and the amount of chlorine ions exceeds 30 ppb per weight of the polyolefin resin composition, the epoxy compound in the polyolefin resin composition A method for manufacturing a substrate storage container, comprising a step of adjusting a mixing ratio to make the amount of chlorine ions 30 ppb or less .

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