JP5122386B2 - Case for semiconductor - Google Patents

Description

  The present invention relates to a semiconductor case that accommodates a reticle or wafer.

  2. Description of the Related Art Conventionally, a semiconductor case is used for transporting and storing reticles and semiconductor wafers used in a semiconductor manufacturing process. As this type of semiconductor case, for example, there is a bottom plate on which a reticle or wafer is placed, and an upper lid that covers the bottom plate, and the bottom plate is a conductive resin having an absolute charge amount of 100 V or less. And an upper lid formed of a non-conductive resin having an absolute charge amount of 1500 V or more (see, for example, Patent Document 1). In such a semiconductor case, generation of particles due to wear between the bottom plate and the upper lid can be suppressed, and the generated particles are electrostatically adsorbed to the upper lid, so that contamination due to adhesion of particles to the reticle or the like can be suppressed. In addition, since no charge is accumulated on the reticle or the like, electrostatic breakdown of the pattern can be prevented.

  Further, a semiconductor case (for example, see Patent Document 2) in which a diamond-like carbon film (hereinafter sometimes referred to as a “DLC film”) is provided on the inner surface by an ionized vapor deposition method has been studied. According to this semiconductor case, it is possible to chemically inactivate the inner surface, increase lubricity, and prevent the detached particles from adhering to the wafer.

In general, DLC films have excellent wear resistance, slidability, gas barrier properties, and the like, and thus have been developed for a wide range of applications. As a film forming method, a high-frequency plasma method and an ionized vapor deposition method (ion plating) are mainly used.
In the high frequency plasma method, methane gas is used as a raw material, and a capacitively coupled plasma electrode is used. It is known that the film quality of the DLC film produced by this method is excellent in smoothness and small friction coefficient because of the large amount of hydrogen in the film, but has a slightly low hardness. In the ionized vapor deposition method, hydrogen is removed from the generated DLC film by using benzene as a raw material and accelerating the ionized hydrocarbon with a direct current. For this reason, it is known that the film quality becomes hard and the surface roughness slightly deteriorates. Therefore, normally, the DLC film by the high frequency plasma method is used for sliding applications, and the DLC film by the ionized vapor deposition method is used for a mold, a blade or the like.

  It is also known that such a DLC film is provided on the inner surface of a plastic container for beverages or the like to improve oxygen gas permeability (see, for example, Patent Document 3). In this case, acetylene or the like is introduced into the container, and microwaves are irradiated to form a DLC film having a maximum thickness of 400 mm (0.04 μm) on the inner surface of the container.

  On the other hand, with the miniaturization of semiconductor device design rules, reticle haze in the exposure process has become a problem. A substance that becomes a seed of haze is formed on the reticle by a reaction between an acid and a base present on the surface or atmosphere of the reticle or a photochemical reaction of an organic impurity. It is known that substances that become seeds of haze aggregate by exposure energy and grow into haze that causes defects.

JP 2001-253491 A JP-A-6-92389 JP 2001-232714 A

  However, in the semiconductor case formed of the conventional resin as described in Patent Document 1, gas derived from the resin such as a stabilizer and an ultraviolet absorber contained in the resin is diffused from the resin and accommodated inside. There is a possibility that they adhere to the reticle or wafer and contaminate them.

  Stabilizers and UV absorbers adhering to reticles and the like cause haze by an organic chemical reaction as an organic impurity, which causes a defect in a pattern transferred to a wafer by exposure.

  Stabilizers contained in the resin include phenolic (2,6-di-t-butyl-4-methylphenol [BHT]), sulfide (dilaurylthiodipropionate [DLTP]), phosphite ( Tridecyl phosphite [TDP]). Examples of ultraviolet absorbers include benzophenone (2-hydroxy-4-methoxybenzophenone), benzotriazole (2 (2′-hydroxy-5-methylphenyl) benzotriazole), and acrylate (2-ethylhexyl-2-cyano-). 3,3-diphenyl acrylate), salicylate type (phenyl salicylate) and the like.

  Since the DLC film formed by ionization vapor deposition as described in Patent Document 2 has high hardness and poor adhesion and followability to the resin, when the inner surface of the semiconductor case is formed of resin However, it was difficult to suppress the diffusion of the gas derived from the resin into the semiconductor case because the DLC film was peeled off or cracked.

  Further, the DLC film described in Patent Document 3 has poor film quality, and there is a possibility that the film is broken due to mechanical impact or the like and becomes dust. For this reason, it cannot be applied to a semiconductor case used for transportation and storage of reticles and wafers to which dust adherence is strictly prohibited.

  This invention is made | formed in view of the said subject, and it aims at providing the case for semiconductors which can suppress the dispersion | distribution of the gas derived from resin to an inside.

FEATURES structure of a semiconductor for the case according to the present invention for achieving the above object is constructed at least the inner surface of a resin, and a case body housing the reticle or wafer, as well as covering the inner surface, the inner surface A diamond-like carbon film that prevents the vaporized substance contained in the resin from being diffused , the hardness of the diamond-like carbon film is in the range of HK500 to 900, and the density is 1.6 to 2.6 g. / Cm ³ and the thickness is in the range of 0.2 to 1.0 μm .

The diamond-like carbon film has good gas permeation resistance. For this reason, by covering the inner surface of the case body with a diamond-like carbon film as in this configuration, the vaporized substance contained in the resin constituting the inner surface of the case body, that is, the resin-derived gas, Can be prevented from being diffused.
Therefore, according to this configuration, it is possible to prevent the gas derived from the resin from being diffused inside the case body and adhere to the reticle or wafer, and the reticle or wafer can be kept stable.

As in this configuration, by configuring the hardness of the diamond-like carbon film to be in the range of HK 5 00~ 9 00, it is possible to follow the volume change of the resin, it becomes difficult crack. For this reason, it is possible to prevent the resin-derived gas from entering the inside of the case body through the cracked gap of the diamond-like carbon film. Further, since the diamond-like carbon film itself is difficult to break, it is possible to prevent film fragments and the like from adhering to the reticle or wafer.

As the diamond-like carbon film has a low density, the gas permeation resistance decreases, and when the density increases, the diamond-like carbon film becomes hard and easily cracked.
Therefore, by setting the density in the range of 1.6 to 2.6 g / cm ³ as in this configuration, it is possible to obtain a diamond-like carbon film that is difficult to break while maintaining good gas permeability.

As in this configuration, the thickness is 0. By setting the thickness within the range of 2 to 1.0 μm, a diamond-like carbon film having excellent gas permeation resistance can be obtained.

The semiconductor case according to the present invention has at least an inner surface made of resin, covers a case main body that accommodates a reticle or wafer, and covers the inner surface, and a vaporized substance contained in the resin diffuses from the inner surface. And a DLC film that prevents this. The hardness of the DLC film is preferably in the range of HK400 to 1000. When the hardness of the DLC film is lowered, the gas permeability resistance is lowered, while when the hardness is increased, the DLC film is easily cracked. For this reason, in the case where the inner surface of the case body formed of resin is covered with the DLC film, the resin constituting the inner surface of the case body is configured by setting the hardness of the DLC film to be in the range of HK400 to 1000. It is possible to follow the elastic deformation of the film, volume changes such as expansion / contraction due to temperature changes during film formation, and the like. Such a DLC film, in addition to excellent gas permeation resistance, is difficult to break against changes in the volume of the resin, etc., so it is possible to suppress the diffusion of gas derived from the resin inside the case body, and the reticle and wafer It can be prevented from being contaminated. This also makes it possible to use a resin that could not be used for a semiconductor case.
The resin-derived gas (vaporizing substance contained in the resin) is not particularly limited. For example, a stabilizer, an antioxidant, an ultraviolet absorber, a plasticizer, a flame retardant, etc. Various additives to be added to the resin, unpolymerized raw material monomers and oligomers, low molecular weight decomposition products generated in the melting step and the like are included.

  The semiconductor case according to the present invention is provided with a case main body that accommodates a reticle or wafer, and a conventionally known shape is applicable and is not particularly limited. The case main body is not particularly limited as long as at least the inner surface is made of resin. As the case main body, for example, a case main body itself formed of a resin, a metal case or the like whose inner side surface is coated with a resin, or the like can be applied.

The resin forming the inner side surface of the case body is not particularly limited, but from the viewpoint of making the DLC film difficult to break, a smaller linear expansion coefficient is preferable because the thermal expansion of the case body can be reduced. Examples of the resin include urea resin, melamine resin, epoxy resin, furan resin, xylene resin, unsaturated polyester resin, silicone resin, diallyl phthalate, aramid resin, polyimide resin, polyvinyl chloride, polyvinyl butyrate, polyvinyl alcohol, polyvinyl formal , Chlorinated polyether, polystyrene, styrene / acrylonitrile copolymer resin, acrylonitrile / butadiene / styrene copolymer resin (ABS), polyethylene, polypropylene, polyacetal, polymethyl methacrylate, modified acrylic resin, antistatic acrylic resin, nylon 6, nylon 6,6, nylon 6,10, nylon 11, nylon 12, ethyl cellulose, cellulose acetate, propyl cellulose, cellulose acetate / butyrate, cellulose nitrate, polycarbonate , Phenoxy resin, polyester, fluororesin (trifluoroethylene chloride (PCTFE), trifluoroethylene chloride / ethylene copolymer resin (ECTEF), tetrafluoroethylene resin (PTFE), tetrafluoroethylene / ethylene Copolymer resin (ETFE), tetrafluoroethylene / hexafluoropropylene copolymer resin (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin (PFA), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) etc.), polyurethane and the like. The linear expansion coefficient of the resin is preferably 13 × 10 ⁻⁵ / ° C. or less, and more preferably 10 × 10 ⁻⁵ / ° C. or less.

  The DLC film that covers the inner surface of the case body is an amorphous carbon film having diamond-like carbon-carbon bonds. There is no restriction | limiting in particular as a DLC film, Other elements, such as hydrogen and a metal, can be contained. The hardness HK of the DLC film is preferably in the range of 400 to 1000. If the DLC film has a hardness exceeding 1000, the DLC film may not follow the volume change of the resin forming the case body, and may crack or peel off from the case body. When the hardness of the DLC film is lower than 400, the gas permeability resistance to a resin-derived gas such as a stabilizer or an ultraviolet absorber is lowered although the volume change of the resin can be followed. For this reason, as for the hardness of a DLC film, HK500-900 is more preferable. The hardness of the DLC film is adjusted by appropriately selecting the frequency / power of the high-frequency power, the degree of vacuum, the processing time, and the like during the DLC film formation. The hardness of the DLC film is, for example, the degree of vacuum: 0.1 Torr, DLC film forming gas: methane / flow rate 500 sccm, temperature: 50 ° C., high frequency power: frequency 13.56 MHz / 400 W / 39 min. The hardness of the DLC film is 900 (HK) under the film forming conditions. Degree of vacuum: 0.1 Torr, DLC film forming gas: methane / flow rate 500 sccm, temperature: 50 ° C., high frequency power: frequency 13.56 MHz / 480 W / 33 min. The hardness of the DLC film is 900 (HK) under the film forming conditions. Degree of vacuum: 0.1 Torr, DLC film forming gas: methane / flow rate 500 sccm, temperature: 50 ° C., high frequency power: frequency 13.56 MHz / 300 W / 135 min. A DLC film hardness of 500 (HK) can be obtained under the film forming conditions. It is said that the hardness of the DLC film decreases as the amount of hydrogen introduced increases, and the hardness of the DLC film tends to increase as the amount of hydrogen introduced decreases.

  Examples of the substance made of carbon include graphite and diamond. Graphite carbon has sp2 bonds, diamond has sp3 bonds, and graphite is more flexible than diamond. The carbon bonds constituting the DLC film include sp2 bonds and sp3 bonds, and the hardness of the DLC film varies depending on the composition ratio of the sp2 carbon and the sp3 carbon. It is said that the hardness tends to increase when the amount of sp3 carbon is larger than that of sp2 carbon.

If the density of the DLC film becomes too small, the gas permeation resistance tends to decrease, and if it becomes too large, it becomes hard and easily cracked. For this reason, it is preferable that the density of a DLC film is 1.6-3.3 g / cm < ³ >. By setting the density of the DLC film within this range, it is possible to obtain a DLC film that is hard to break while maintaining good gas permeability against a resin-derived gas. The density of the DLC film is adjusted by appropriately selecting the frequency / power of the high-frequency power, the degree of vacuum, the processing time, and the like during the DLC film formation. The density of the DLC film is, for example, the degree of vacuum: 0.1 Torr, DLC film forming gas: methane / flow rate 500 sccm, temperature: 50 ° C., high frequency power: frequency 13.56 MHz / 400 W / 39 min. The density of the DLC film under the following film formation conditions: 2.0 g / cm ³ . Degree of vacuum: 0.1 Torr, DLC film forming gas: methane / flow rate 500 sccm, temperature: 50 ° C., high frequency power: frequency 13.56 MHz / 480 W / 33 min. DLC film density: 2.4 g / cm ^{3 under the following} film formation conditions. Degree of vacuum: 0.1 Torr, DLC film forming gas: methane / flow rate 500 sccm, temperature: 50 ° C., high frequency power: frequency 13.56 MHz / 300 W / 135 min. The density of the DLC film: 1.8 g / cm ³ is obtained under the film forming conditions. In general, as the amount of hydrogen introduced into the DLC film increases, the density of the DLC film tends to decrease. Further, the DLC film is said to tend to have a low density regardless of the hardness when the crystallinity is low or amorphous depending on the composition ratio of sp2 carbon and sp3 carbon.

Such a DLC film can be produced by, for example, a plasma CVD method, a PVD method such as a sputtering method or an ion plating method, and is not particularly limited. Further, before the DLC film is formed, the inner surface of the case body can be exposed to plasma of one or more kinds of pretreatment gases such as fluorine-containing gas, hydrogen gas, oxygen gas, etc. as pretreatment. The inner surface of the case body can be cleaned by such pretreatment. In addition, when exposed to plasma of a pretreatment gas containing fluorine-containing gas or hydrogen gas, the inner surface of the case body is covered with fluorine or hydrogen, so that the adhesion with the DLC film is improved. When exposed to the plasma of the pretreatment gas containing oxygen gas, the organic matter adhering to the inner surface of the case body can be removed. In the pretreatment, a plurality of plasma treatments using the same kind or different kinds of pretreatment gases can be performed. Examples of the fluorine-containing gas include fluorine (F ₂ ) gas, nitrogen trifluoride (NF ₃ ) gas, sulfur hexafluoride (SF ₆ ) gas, carbon tetrafluoride (CF ₄ ) gas, and silicon tetrafluoride (SiF _4). ), Silicon hexafluoride (Si ₂ F ₆ ) gas, chlorine trifluoride (ClF ₃ ) gas, hydrogen fluoride (HF) gas, and the like.

It is particularly preferable to use the plasma CVD method as a method of manufacturing the DLC film because the pretreatment and the formation of the DLC film can be performed with the same apparatus. As a gas for forming a DLC film in the plasma CVD method, a gas usually used for forming a DLC film can be applied, and methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ ). Examples thereof include hydrocarbon compound gases such as H ₁₀ ), acetylene (C ₂ H ₂ ), and benzene (C ₆ H ₆ ). Moreover, hydrogen gas, inert gas, etc. can also be mixed with these hydrocarbon compound gas as carrier gas as needed.

  In the plasma CVD method, for example, a plasma CVD apparatus 1 shown in FIG. 1 can be used. The plasma CVD apparatus 1 includes a chamber 2, an exhaust pump 3 for evacuating the chamber 2, and a gas cylinder 4 that supplies a gas serving as a plasma raw material to the chamber 2. A pressure regulating valve 3a is provided between the chamber 2 and the exhaust pump 3 so that the inside of the chamber 3 can be adjusted to a predetermined pressure. The gas cylinder 4 includes a pretreatment gas cylinder 41 for supplying a pretreatment gas and a DLC film formation gas cylinder 42 for supplying a DLC film formation gas. Between each gas cylinder 4 and the chamber 2, a flow rate controller is provided. (MFC) 5 and a pressure regulating valve 4a are provided so that the flow rate of the gas supplied to the chamber 2 can be controlled. Inside the chamber 2, a power application electrode 6 for applying power and a ground electrode 7 facing the power application electrode 6 are provided. The power application electrode 6 is provided so that the case body can be disposed thereon, and includes a heater 61 that adjusts the temperature of the case body. The power application electrode 6 is provided with a high frequency power generation device 9 including a high frequency amplifier 91 and a high frequency arbitrary waveform generation device 92 via a matching box 8 so that high frequency power can be applied. Since the plasma raw material gas introduced into the chamber 2 can be converted into plasma by the plasma CVD apparatus 1 as described above, the case main body is disposed on the power application electrode 6 so that a predetermined surface of the case main body is formed. A DLC film can be formed. In addition, as another structure of the plasma CVD apparatus 1, the structure of a conventionally well-known plasma CVD apparatus, such as providing the power application electrode 6 with cooling means such as water cooling for suppressing a temperature rise, can be added. As the operation method of the plasma CVD apparatus 1, a conventionally known method such as a pulse modulation operation can be adopted. For example, the apparatus and method described in Japanese Patent No. 3119172 can be used.

  As an example of a method for manufacturing a semiconductor case using the plasma CVD apparatus 1, first, as a pretreatment, the case body is placed on the power application electrode 6 of the chamber 2 at room temperature to 60 ° C. and evacuated. The pretreatment gas is introduced until a predetermined pressure is reached, and plasma cleaning is performed. Next, the pretreatment gas is exhausted at a room temperature to 50 ° C., a DLC film forming gas is introduced, and a DLC film is formed.

  The thickness of the DLC film thus formed is not particularly limited, but is preferably 0.05 to 1.0 μm. When the thickness of the DLC film decreases, the gas permeation resistance tends to decrease, and when the thickness increases, the film itself tends to harden. The thickness of the DLC film can be controlled by, for example, the plasma processing time. The film thickness increases as the processing time increases, and the film thickness decreases as the processing time decreases. In addition, the DLC film can be formed as a single-layer film, or can be formed as a multi-layer film using the same or different plasma source gas.

  The hardness of the DLC film can be controlled by, for example, the applied high frequency power. When the high frequency power is increased, the effect of ion irradiation is increased and the amount of hydrogen in the film is reduced, so that the hardness of the DLC film is increased.

  In the semiconductor case according to the present invention, the amount of gas generated inside can be reduced as compared with the conventional semiconductor case, so that it is possible to prevent the gas from adhering to the reticle or wafer to be accommodated.

  Hereinafter, examples using the present invention will be shown to describe the present invention in more detail. However, the present invention is not limited to these examples.

  Using a Bayon base material (7 cm × 21 cm × 3.5 mm) manufactured by Kureha Co., Ltd., which is an acrylic antistatic resin, the plasma CVD apparatus 1 shown in FIG. After the DLC film was formed, the amount of gas generated from the substrate was examined.

  The gas generated from the substrate was sampled by the apparatus shown in FIG. That is, the tester 11 was set on the substrate 10, the standard gas supplied from the gas cylinder 12 was passed through the zero gas filter 15, and then passed through the tester 11 and collected by the GC filler 16. 13 is a pressure regulating valve, 14 is a flow meter, and 17 is an exhaust pump. The standard gas was high purity nitrogen gas and the flow rate was 60 sccm. The gas collection time was 100 minutes. The gas collected by the GC filler 16 was measured as a total organic matter TOC (toluene conversion) by a GC-MS analyzer.

The pretreatment was performed under the following conditions at a temperature of 60 ° C. or lower.
Pretreatment gas: hydrogen (H ₂ ) gas, 500 sccm
High frequency power: frequency 13.56MHz, 300W
Degree of vacuum: 0.1 Torr
Processing time: 1 min

After performing the pretreatment, the degree of vacuum is 0.1 Torr, methane (CH ₄ ) gas is supplied as a DLC film forming gas at a flow rate of 500 sccm, the temperature is 50 ° C. or less, the frequency is 13.56 MHz, and the conditions shown in Table 1 A high frequency power was applied to form DLC films having different thicknesses, hardnesses, and densities (Examples 1 to 35). The modulation frequency was 1 kHz and the duty ratio was 50%.
The amount of gas generated for each base material on which each DLC film was formed was examined and is shown in Table 2 and FIG. The amount of gas was calculated by subtracting the amount of gas when the substrate was not set (tester blank) from the amount of gas when the substrate was set in the sampling device. Further, for the base material on which no DLC film was formed, the amount of gas generated as a comparative example was examined and shown in Table 2.

As a result, as shown in Table 2, it was confirmed that the amount of gas generated could be suppressed by providing a DLC film of HK400 to 1000 on the substrate. As shown in FIG. 3, it was found that the amount of gas generated increases when the hardness of the DLC film is low. It was also found that cracking occurred and the amount of gas increased as the hardness of the DLC film increased. For this reason, the hardness of the DLC film is preferably HK 500 to 900, and more preferably HK 500 to 700.
As for the thickness of the DLC film, it was found that the larger the amount of the generated gas tends to decrease, but in the DLC film having a hardness of HK900 and 1000, cracking occurs when the film thickness increases, and the amount of gas is increased. It was a lot. For this reason, the thickness of the DLC film is preferably 0.05 to 1 μm, more preferably 0.2 to 1 μm, and still more preferably 0.5 to 1 μm.

  The present invention can be applied to a semiconductor case for carrying and storing a reticle or wafer, such as a reticle case or a wafer storage case.

Schematic diagram of plasma CVD equipment Schematic diagram of sampling device Graph showing the amount of gas generated for each hardness and thickness of DLC film

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma CVD apparatus 2 Chamber 6 Power application electrode 7 Ground electrode 9 High frequency electric power generator

Claims (1)

A case main body having at least an inner surface made of resin and containing a reticle or wafer;
A diamond-like carbon film that covers the inner side surface and prevents the vaporized substance contained in the resin from being diffused from the inner side surface ,
Hardness of the diamond-like carbon film is in the range of HK500～900, density is in the range of 1.6~2.6g / cm ^3, area by near the thickness 0.2~1.0μm semiconductor For case.

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