Semiconductor wafer transport container and method for manufacturing same

Abstract

A semiconductor wafer transport container according to one embodiment comprises a plastic container for accommodating a semiconductor wafer. The vicinity of the surface of the plastic at least at an inner surface of the plastic container is impregnated with an aluminum oxide having a hydroxyl group. A structure in which 1 at% or more of the aluminum oxide is dispersed in the plastic, in terms of the concentration of elemental aluminum, is present at least at a depth within a range of 50 nm to 10 μm inclusive from the inner surface.

Description

Semiconductor wafer transport container and its manufacturing method

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a semiconductor wafer transport pod and a method for manufacturing the same.

[0002] In semiconductor manufacturing processes, semiconductor wafers are processed using a wide variety of chemicals and gases. After each processing step, semiconductor wafers are stored in a front-opening unified pod (FOUP), a semiconductor wafer transport container, and then moved to the next process. The chemicals and gases used in these processes remain in the FOUP as airborne molecular contaminants (AMCs) and permeate the resin that makes up the FOUP, creating a problem. These AMCs are gradually released from the FOUP over time, causing deterioration of semiconductor elements and wiring and equipment failure. For this reason, the polymers that make up FOUPs need to be made of materials that prevent gases from penetrating the interior, or that do not release gases even if they do penetrate.

[0003] US Patent No. 6976585 JP 7-254636 JP 4-180248

[0004] The problem to be solved by the present invention is to provide a semiconductor wafer transport container that does not allow AMC to penetrate inside, or that does not release AMC even if it penetrates, and a method for manufacturing the same.

[0005] The semiconductor wafer transport container of the embodiment is a semiconductor wafer transport container equipped with a resin container for storing semiconductor wafers, and aluminum oxide having hydroxyl groups is impregnated into at least the resin on the inner surface of the resin container near the surface, and a structure in which the aluminum oxide is dispersed in the resin at a concentration of 1 atomic % or more in terms of aluminum element concentration exists at least within a range of 50 nm to 10 μm in depth from the inner surface.

[0006] 1 is a diagram showing a semiconductor wafer transport container according to an embodiment of the present invention; ２ Oxidized to Al(OH) ３ This is a diagram showing the energy diagram of the process of Al(OH) of HF. ３Illustrates the adsorption process of HCl onto Al(OH). ３ Illustrates the adsorption process onto NH ３ Al(OH) ３1 is a diagram showing an adsorption process to TMA. FIG. 1 is a diagram showing an analysis result of the composition distribution of elements on the PC surface of the FOUP inner wall when the exposure temperature to TMA is 100°C in Example 1. FIG. 2 is a diagram showing an analysis result of the composition distribution of elements on the PC surface of the FOUP inner wall when the exposure temperature to TMA is 125°C in Example 1. FIG. 3 is a diagram showing an analysis result of the composition distribution of elements on the PC surface of the FOUP inner wall when the exposure temperature to TMA is 150°C in Example 1. FIG. 4 is a diagram showing an analysis result of the composition distribution of elements on the PC surface of the FOUP inner wall when the exposure temperature to TMA is 175°C in Example 1. FIG. 5 is a diagram showing an analysis result of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 125°C and the TMA pressure is 100 Pa in Example 2. FIG. 6 is a diagram showing an analysis result of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 125°C and the TMA pressure is 300 Pa in Example 2. 1 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 125° C. and the TMA pressure is 900 Pa in Example 2. FIG. 2 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 110° C. and the TMA pressure is 100 Pa in Example 2. FIG. 3 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 110° C. and the TMA pressure is 300 Pa in Example 2. FIG. 4 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 110° C. and the TMA pressure is 900 Pa in Example 2. FIG. 5 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature is 100° C. and the TMA pressure is 300 Pa in Example 2. FIG. 10 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall when the temperature was 100° C. and the TMA pressure was 900 Pa in Example 2. FIG. 11 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall before the HF exposure test in Example 4. FIG. 12 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall after the HF exposure test in Example 4. FIG. 13 is a diagram showing the analysis results of the composition distribution of elements on the PC surface of the FOUP inner wall in Examples 3A and 5 (before the HF exposure test in Example 5).10A and 10B are diagrams showing the analysis results of the composition distribution of elements on the PC surface of the inner wall of a FOUP after an HF exposure test in Example 5. FIG. 10B are diagrams showing the analysis results of the composition distribution of elements on the PC surface of the inner wall of a FOUP after an HF exposure test in Example 6.

[0007] The semiconductor wafer transport container of the embodiment will be described below with reference to the drawings. In each embodiment, substantially identical components are designated by the same reference numerals, and their description may be omitted. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each component, and the like may differ from the actual ones. Terms indicating directions such as up and down in the description refer to relative directions when the substrate surface of a semiconductor wafer stored in a semiconductor wafer transport container (described later) is considered to be up, unless otherwise specified, and may differ from actual directions based on the direction of gravitational acceleration.

[0008] FIG. 1 shows an example of a semiconductor wafer transport container (FOUP) according to an embodiment. The FOUP 1 shown in FIG. 1 includes a resin container body 2 for storing semiconductor wafers. The resin container body 2 has a front opening. The front opening 3 of the resin container body 2 can be closed by a resin door 4. The FOUP 1 includes a resin container 5 composed of the resin container body 2 and the resin door 4. A wafer support 6 for supporting semiconductor wafers is provided inside the resin container body 2. While only one wafer support 6 is shown in FIG. 1 , a pair of opposing wafer support parts 6 are actually provided, and this pair of spaced-apart wafer support parts 6 supports multiple semiconductor wafers (not shown) in parallel. Furthermore, the resin container body 2 includes a gas outlet / inlet port 7. As described below, the surface treatment according to the embodiment is applied to at least the inner wall (inner surface) 2a of the resin container body 2 and the inner wall (inner surface) 4a of the resin door 4.

[0009] Resins that are mainly composed of polycarbonate (PC) and mixed with various other materials are widely used as resin materials for FOUPs. PC, for example, is also used as the material for the resin container 5 of the embodiment. PC has a moderate hardness and a high glass transition temperature (Tg) of 175°C, so it exhibits excellent properties for use as a container. On the other hand, PC is known as a resin with high gas permeability. The oxygen gas permeability of PC is 4700 cm ３ / m ２ 24h atm, water vapor permeability is 170g / m ２ ・24 hours. 80 cm of polyethylene terephthalate (PET), which has a similar molecular structure, ３ / m ２ ・24h・atm, 20g / m ２ - It shows a considerably larger value than 24h. Due to these characteristics, the permeability of AMC, a molecular contaminant, is also high, and this is considered to be the main reason why PC is easily contaminated with AMC.

[0010] The use of resins with low AMC permeability instead of PC is also being considered. For example, in the case of polyetherimide (PEI), polar groups are placed and the polarity is fixed to achieve a high glass transition temperature (Tg), physically suppressing the diffusion rate of AMC. Furthermore, in the case of cyclic olefin polymer (COP), the solubility parameter (surface energy) of the resin is lowered to prevent energetic compatibility with AMC, which has high polarity and surface energy. FOUPs using these resins have also been put into practical use. However, these resins are more difficult to synthesize than the general-purpose resin PC, and as a result, the price of FOUPs tends to be higher.

[0011] The semiconductor wafer transport container (FOUP) 1 of the embodiment addresses the above-mentioned issues by simply performing surface treatment on the resin that constitutes the FOUP 1, thereby realizing a FOUP 1 that is free from AMC contamination. The surface treatment according to the embodiment is cost-effective for general-purpose resins such as PC, but is not limited to this and can be applied to most resins, and can also be applied to FOUPs 1 that use PEI or COP as described above.

[0012] In the first embodiment, the AMC that has penetrated into the resin is fixed and prevented from being released from the resin again. In the second embodiment, the surface of the resin material that constitutes the FOUP is appropriately treated to form a protective film that prevents the AMC from penetrating into the resin. In the third embodiment, the resin surface is treated to prevent the AMC molecules from adsorbing, thereby preventing the AMC from penetrating into the resin. These first to third embodiments can also be combined. Each embodiment will be described in detail below.

[0013] 1, a semiconductor wafer transport container 1 of the first embodiment includes a resin container 5 made up of a resin container body 2 for storing semiconductor wafers and a resin door section 4 for closing a front opening 3 of the resin container body 2. In the first embodiment, an aluminum oxide (e.g., AlO) having a hydroxyl group is deposited near the resin surface of at least the inner wall (inner surface) 2a of the resin container body 2 and the inner wall (inner surface) 4a of the resin door section 4. ｘ + Al(OH) ３ Such aluminum oxide is impregnated with AMC (e.g., HF, HCl, NH ３ For example, when the AMC is HF, the Al(OH) impregnated in the resin traps the Al(OH) ３ By capturing F through Al--F bonds, AMC(HF) that has penetrated into the resin is prevented from being released.

[0014] The aluminum oxide having hydroxyl groups capable of capturing AMC is impregnated into the resin of the inner surface 2a of the resin container body 2 and the inner surface 4a of the resin door portion 4 at a concentration of 1 atomic % or more, calculated as an aluminum element concentration. The range (distribution range) impregnated with aluminum oxide at a concentration of 1 atomic % or more, calculated as an aluminum element concentration, exists at least within a range of 50 nm to 10 μm deep from the surface of the inner surfaces 2a and 4a. By impregnating such a range with aluminum oxide having hydroxyl groups at a concentration of 1 atomic % or more, calculated as an aluminum element concentration, it is possible to obtain the ability to capture AMC (HF, etc.) and the release prevention properties based thereon. The concentration of aluminum oxide having hydroxyl groups in the above-mentioned impregnation range (distribution range) is preferably in the range of 5 atomic % to 30 atomic % calculated as an aluminum element concentration. By impregnating the above-mentioned impregnation range (distribution range) with aluminum oxide at a concentration of 5 atomic % or more, calculated as an aluminum element concentration, it is possible to more effectively obtain the ability to capture AMC and the release prevention properties based thereon. However, if aluminum oxide is impregnated into the above-mentioned impregnation range (distribution range) at a concentration of more than 30 atomic % in terms of aluminum element concentration, the inherent properties of the resin may be deteriorated, which may result in deterioration of properties such as the handleability of the semiconductor wafer transport container (FOUP) 1.

[0015] In the first embodiment, as described above, a structure that chemically inactivates AMC is formed within the resin that constitutes the FOUP 1. The compound that inactivates AMC (hereinafter referred to as the trapping agent) exists in a state dispersed at the molecular level within the resin. Therefore, AMC that has penetrated into the resin diffuses within the resin, but when it encounters the trapping agent present within the resin, it chemically bonds and is inactivated. At this time, because the trapping agent is dispersed at the molecular level, it reacts and immobilizes AMC molecules as they approach. Since the inactivated AMC does not become a gas again, it is immobilized within the resin and is not released from the resin.

[0016] To form a structure in which a trapping agent is dispersed in a resin, a vacuum device employing the atomic layer deposition (ALD) method is used. Although a device similar to an ALD device is used, its purpose is to impregnate a resin with a trapping agent precursor, rather than depositing an atomic layer on a substrate, as will be described in the second embodiment below. Therefore, the precursor exposure time is longer and the number of cycles is fewer than in conventional ALD. The following experiment was performed in exposure mode, in which the valve is closed after gas introduction and the pressure is maintained at that state.

[0017] A sample is placed in a chamber and the pressure is reduced. In the case of FOUP1, the adsorption of AMC to the inner walls of FOUP1 becomes a problem. FOUP1 has a gas outlet port 7 that allows the introduction of an inert gas into the chamber or reduces the pressure inside. It is also possible to reduce the pressure through the gas outlet port 7 of such a FOUP1 to form a trap structure only on the inner walls of FOUP1. Bottles containing a trapping agent precursor and an oxidizer are attached, and the precursor is supplied to the depressurized chamber or FOUP1 and allowed to permeate the resin. Alkyl aluminum is used as the precursor. The precursor generally consists of a central metal and a ligand, which means it has low polarity and a low boiling point. Therefore, it diffuses and permeates into the resin. After permeation has progressed to a certain extent, the oxidizer is switched on. The precursor then reacts with the oxidizer to form a metal (hydr)oxide. Because the precursor is dispersed and diffused in the resin in a molecular state, even after oxidization, it remains dispersed at the molecular level within the resin.

[0018] With many resins, it is possible to form a dispersed structure of the trapping agent within the resin with just one of the above operations. Specifically, polymers containing carbonyl groups in their chemical structure, such as PC, PEI, PET, and polymethylmethacrylate (PMMA), can be impregnated with a certain amount of precursor in a single operation because the precursor is physically adsorbed near the unpaired electron pair of the oxygen atom of the carbonyl group. Oxidizing this allows for the formation of a sufficient amount of trapping agent. A similar phenomenon occurs with groups other than carbonyl groups that have unpaired electron pairs, such as cyano, amino, and nitro groups.

[0019] The precursor pressure should be between 10 Pa and 5 kPa. If the pressure is less than 10 Pa, a sufficient number of precursor molecules will not be supplied, and a trap layer will not be formed adequately. On the other hand, if the pressure is higher than 5 kPa, the molecules will not diffuse uniformly into the resin. In practice, a good trap layer will be formed at a pressure between 50 Pa and 1 kPa. When the resin is PC or PET, many gases are contained within the PC or PET, and these gases react with the precursor on the surface. For this reason, if the pressure is less than 10 Pa, precipitates are likely to form on the surface. Furthermore, the exposure time is preferably 30 seconds or more, and preferably 1 hour or less. More preferably, it is 5 minutes to 20 minutes, and within this range, a relatively uniform trap layer will be formed.

[0020] The depth distribution of the resulting trap layer follows a diffusion equation when the precursor pressure is low, but follows the molar content of unpaired electron pairs when the pressure is high, making it nearly constant in the depth direction. The thickness of the trap layer in the depth direction is preferably 50 nm or more and 10 μm or less from the inner surface. If it is less than 50 nm, a sufficient trapping amount cannot be ensured. A thicker layer does not pose a problem in terms of trapping ability, but the process takes too long, increasing manufacturing costs.

[0021] In contrast, resins composed only of carbon and hydrogen atoms, such as COP and polystyrene (PS), have no precursor adsorption sites and therefore impregnate a small amount of precursor. Furthermore, they also do not adsorb alcohol groups or phenolic hydroxyl groups. When using such resins, the above operation is carried out multiple times. In this case, trimethylaluminum (TMA / Al(CH ３ ) ３ ) and H ２ Oxidize with AlO ｘ or Al(OH) ３ When forming AlO, the number of times the precursor is exposed is first nucleated because there is no adsorption site in the molecular structure. ｘ or Al(OH) ３ is formed in the resin and then exposed to light several times to grow. In this case, AlO formed in the first time ｘ or Al(OH) ３ Since the amount of the trapping layer is small, it is preferable to repeat the exposure five or more times. The thickness of the trapping layer in the depth direction in this case is 50 nm or more and 10 μm or less. If it is less than 50 nm, a sufficient amount of trapping cannot be ensured. If it is thicker, there is no problem with the trapping ability, but the process takes too long.

[0022] Figure 2 shows the TMA ２ Oxidized to Al(OH) ３ This calculation was performed using the density functional theory (DFT) program Gaussian, with the general B3LYP / 6-31G* functional. ｘ TMA and H as precursors of ２ The reaction of TMA with H ２ It is also oxidized by O. Note that ozone or plasma oxygen may be used for oxidation. It is assumed that TMA is diffused and isolated in the resin.

[0023] TMA CH ３ Ligand is H ２Calculations have shown that there is a transition state (TS) barrier for each oxidation process. The barrier for the first oxidation reaction is 12.2 kcal / mol, the second is 15.4 kcal / mol, and the third is 17.5 kcal / mol. With barriers of this magnitude, the reaction proceeds easily with only a small amount of heat, and finally Al(OH) ３ It is also believed that the reaction will proceed due to the humidity in the air even when left at room temperature. Therefore, the aluminum (hydr)oxide formed in the resin by TMA exposure is Al(OH) ３ It is thought that the temperature will stabilize in the following manner.

[0024] The precursor diffuses into the resin at the molecular level, and when it is exposed to an oxidizing agent, the reaction proceeds spontaneously, forming a metal hydroxide as the reaction product. Because the reaction product has a high polarity and a high boiling point, it cannot move within the resin and is fixed in the resin in a molecularly dispersed state.

[0025] The precursor is selected, for example, as follows, taking into account that the trapping agent molecules chemically adsorb the AMC molecules. Since the trapping agent in the first embodiment is a metal oxide, if the bond energy between the trapping agent and the elements constituting the AMC is greater than the bond energy between the metal and oxygen, the AMC can be immobilized on the metal of the metal oxide. Halogen atoms are primarily considered as the AMC. The bond energies between various elements are described in, for example, the CRC Handbook of Chemistry and Physics 95th 2014-2015. The precursor ligand is closely related to the reactivity of the central metal. However, a small bulkiness that prevents inadvertent oxidation is advantageous for diffusion into the resin. Specific examples include alkyl groups with 6 or fewer carbon atoms, such as methyl, ethyl, propyl, and butyl groups, and alkoxy groups with 6 or fewer carbon atoms, such as methoxy, ethoxy, propoxy, and butoxy groups.

[0026] Figure 3 shows the trapping agent (Al(OH)) for hydrogen fluoride (HF), which is the main AMC. ３ ) is shown. Figure 4 shows the adsorption process of hydrogen chloride (HCl), a major AMC, onto a trapping agent (Al(OH) ３) adsorption process onto the main AMC, ammonia (NH ３ ) trapping agent (Al(OH) ３ Regarding the trapping ability of AMC, aluminum oxide and the like are used as adsorbents for fluoride in water treatment, but there is little information available on other AMCs. For this reason, AMCs are used to trap HF, HCl, NH ３ Assuming Al(OH) ３ The reaction pathway was calculated when the compound was adsorbed onto the surface of the catalyst.

[0027] In HF, as shown in Figure 3, HF is Al(OH) ３ There is no obstacle to the direct approach to Al of Al(OH) ３ The energy of the trapped state is -47.7 kcal / mol, which is very deep compared to the initial state, so it is thought that the reaction proceeds rapidly up to this point. After this, AlF(OH) ２ and H ２ To separate into O, energy must be gained. This state is more stable than the initial state, but F is Al(OH) ３ Since the state in which the atom is trapped is the most stable, it is thought that the reaction stops in the trapped state.

[0028] In the case of HCl, as shown in FIG. 4, HCl is converted into Al(OH) ３ There is a shallow metastable state near the transition point, but the barrier to the transition state is not so high, so the reaction proceeds as it is. ３ The energy of the trapped state is -35.0 kcal / mol deeper than the initial state. ２ and H ２ To separate into O, it is necessary to acquire energy. Cl is Al(OH) ３ It is thought that the most stable state is when the atom is trapped, and that the reaction stops when the atom is trapped.

[0029] NH ３ is a base, so the situation is different. ３ is Al(OH) ３There is a metastable state when the reaction approaches , but the barrier to the transition state is not so high, so the reaction is thought to proceed as it is. Up to this point, it is the same as HCl. After that, NH ３ is Al(OH) ３ The acid is trapped by the base NH ３ There are concerns about its effectiveness against Al(OH) ３ is adsorbed due to its special property as an amphoteric oxide.

[0030] From the above, H in the resin ２ TMA reacted with O is Al(OH) at the molecular level. ３ and forming HF, HCl, NH ３ It is expected that the compound has a trapping ability for . The first embodiment is based on the above-mentioned principle. Similarly, it is thought that a similar reaction will proceed with other acids and bases. Furthermore, since a similar reaction is thought to occur with Group 13 metal elements, Ga, In, Ti, etc. can also be used.

[0031] Second Embodiment As shown in FIG. 1 , a semiconductor wafer transport container 1 according to a second embodiment includes a resin container body 2 for storing semiconductor wafers and a resin door section 4 for closing a front opening 3 of the resin container body 2. In the second embodiment, a metal oxide film is formed on at least the inner surface 2a of the resin container body 2 and the inner surface 4a of the resin door section 4. The metal oxide film contains at least one selected from the group consisting of aluminum oxide, silicon oxide, and zirconium oxide. Such a metal oxide film is formed on the inner surface 2a of the resin container body 2 and the inner surface 4a of the resin door section 4 via a mixed layer of resin and metal oxide.

[0032] The metal oxide film preferably has a thickness of 20 nm or more and 1 μm or less. The mixed layer preferably has a thickness of 10 nm or more and 1 μm or less. By forming the metal oxide film on the inner surface 2 a of the resin container body 2 and the inner surface 4 a of the resin door portion 4 via a mixed layer of resin and metal oxide, the adhesion of the metal oxide film can be improved. Therefore, the metal oxide film, which functions as a protective film against the AMC, can prevent the AMC from penetrating into the resin.

[0033] In the second embodiment, as described above, the surface of the resin material constituting the FOUP 1 is appropriately treated to form a protective film that prevents AMC from penetrating into the resin. Examples of methods for forming the protective film include chemical methods such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). Unlike physical methods such as physical vapor deposition (PVD), these methods do not prevent the formation of the protective film in shadowed areas even if the inner wall of the FOUP 1 is uneven. As a result, a ceramic protective film can be conformally formed on the inner wall of the FOUP 1. In this case, a protective film with a thickness of 20 nm or more can block AMC.

[0034] However, the above-described formation method is almost the same as that in the first embodiment. Therefore, if the resin is exposed to the precursor as is, the precursor will penetrate into the resin, preventing it from being deposited as a film. The PC commonly used in FOUP 1 has high gas permeability and does not form a protective film. Therefore, when applying ALD, it is preferable to alternately expose the resin to the precursor and the oxidizer in a short period of time. This allows the precursor to penetrate the resin to some extent during the first few cycles, but oxide growth can be initiated from the oxide generated near the resin surface. The number of repeated cycles of alternate exposure to the precursor and the oxidizer is preferably 10 to 1,000. If the number of cycles is less than 10, it is difficult to sufficiently grow the oxide. If the number of cycles is more than 1,000, the metal oxide film becomes too thick and the process takes too long, increasing manufacturing costs.

[0035] The difference in process conditions from the first embodiment is the exposure time per exposure, which is preferably 1 second or more and 10 seconds or less. If the exposure time is longer than 10 seconds, the precursor will penetrate into the resin, making it difficult to obtain a strong protective film. If the exposure time is shorter than 1 second, the amount of precursor exposed per exposure is too small, making it difficult to sufficiently grow an oxide. Furthermore, after the precursor is exposed, it is preferable to expose it to an oxidizing agent for 10 seconds or less to oxidize and fix the precursor. This allows for sufficient oxide growth. By repeating this process multiple times, a thin film of metal oxide can be formed on the resin surface. Furthermore, the pressure during exposure to the precursor is preferably 1 Pa or more and 300 Pa or less. If the exposure pressure is less than 1 Pa, an insufficient precursor is supplied, reducing the formation of the metal oxide and making it difficult to grow the metal oxide. If the exposure pressure exceeds 300 Pa, the precursor will easily penetrate into the resin, making it difficult to sufficiently grow a strong metal oxide. In order to further increase the purity of the metal oxide and improve the film quality, the pressure during exposure to the precursor is preferably 100 Pa or less. After exposure to the precursor, the precursor is exhausted and an oxidizing agent is introduced. The oxidizing agent may be water, ozone, or plasma oxygen. The oxidizing agent is then exhausted. This cycle is repeated. After exhausting the precursor and oxidizing agent, argon gas or the like may be introduced. Unlike the first embodiment, this process does not depend on the resin composition.

[0036] The protective film formed by the surface treatment may be made of at least one material selected from aluminum oxide, silicon oxide, and zirconia oxide. Materials for forming such metal oxides include at least one selected from alkyl metals, alkoxy metals, and alkylamino metals. Aluminum oxide precursors include trialkylaluminums and trialkoxyaluminums, each having an alkyl group with 1 to 6 carbon atoms. Silicon oxide precursors include bis(alkylamino)silanes, aminoalkyltrialkoxysilanes, tetraalkoxysilanes, trialkoxysilanols, trialkylsilanes, and tris(dialkylamino)silanes, each having an alkyl group with 1 to 6 carbon atoms. Zirconium oxide precursors include tetrakis(dialkylamino)zirconiums and zirconium(IV) alkoxides, each having an alkyl group with 1 to 6 carbon atoms. Examples of alkyl groups with 1 to 6 carbon atoms include methyl, ethyl, propyl, and butyl groups. When multiple alkyl groups are attached, the alkyl groups may have different carbon atoms, or the alkyl groups may be branched.

[0037] In the second embodiment, the protective film formed by the resin surface treatment method is preferably a metal oxide film having a thickness of 20 nm to 1 μm. If the protective film is less than 20 nm thick, the AMC blocking properties are reduced. If the protective film is thicker than 1 μm, the AMC blocking properties are sufficient, but peeling and other problems are more likely to occur, and the process takes too long, increasing manufacturing costs. Furthermore, the metal oxide film is formed via a mixed layer of resin and metal oxide having a thickness of 10 nm to 1 μm. The formation of such a mixed layer spatially alleviates the difference in surface energy between the resin and the metal oxide, enabling strong adhesion. The thickness of the mixed layer can be determined by performing elemental analysis while etching.

[0038] When surface treating resins, it is preferable to use precursors with low reaction temperatures. For example, in the case of trialkylaluminum, an aluminum precursor, the bond energy between Al and C atoms is 267.7 kJ / mol, so the reaction occurs even at approximately 100°C. Therefore, the reaction can occur at relatively low temperatures within the heat resistance temperature range of most resins that make up the FOUP 1. In contrast, the bond energy between Si atoms or Zr atoms and C atoms is greater than the bond energy between Al and C atoms, so the reaction temperature may be as high as 200°C or higher. This may limit the applicable resins in some cases. For these reasons, it is more preferable to use aluminum oxide.

[0039] Furthermore, since the AMC contains HF, silicon oxide reacts with the HF, and some of the silicon oxide may volatilize and peel off from the surface of the protective film. For this reason, aluminum oxide is more preferable than silicon oxide as the protective film. Furthermore, if the trap structure of the first embodiment is formed on the resin surface and then the protective film of the second embodiment is formed, a synergistic effect can be obtained, further enhancing the contamination prevention effect of the AMC.

[0040] 1, a semiconductor wafer transport container 1 according to a third embodiment includes a resin container body 2 for storing semiconductor wafers and a resin door 4 for closing a front opening 3 of the resin container body 2. In the third embodiment, a self-assembled monolayer (SAM) having an alkyl group having 8 to 32 carbon atoms is provided on at least the inner surface 2a of the resin container body 2 and the inner surface 4a of the door 4. Such a SAM can suppress the adsorption of AMC molecules. Therefore, the penetration of AMC molecules into the resin can be prevented.

[0041] In the third embodiment, as described above, the resin surface is treated to prevent AMC molecules from adsorbing, and as a result, AMC does not penetrate into the resin. When considering the process by which AMC molecules penetrate into a resin, it is known that adsorption to the resin surface occurs as the first step. One solution would be to reduce the surface energy of the polymer material that makes up the resin, but changing the material itself is difficult and costly.

[0042] AMC molecules are HF, HCl, NH ３ These resins have high surface energy because they are ionic or polar molecules such as carboxyl groups, hydroxyl groups, and ester groups in the polymer chemical structure. These are fixed by Coulomb forces and hydrogen bonds, improving rigidity. For this reason, the presence of polar groups in these resins makes them more likely to attract AMC. In contrast, if the surface energy of the resin surface is reduced, AMC molecules will no longer adsorb to the resin surface. If AMC molecules are not present on the surface, they will not diffuse into the interior.

[0043] However, there are limited methods for changing the polarity of a resin surface from a high polarity state to a low polarity state. In the third embodiment, a method for lowering the surface energy of only the resin surface by surface treatment is used. Materials for forming SAMs include alkylamines, alkylphosphonic acids, and alkylalkoxysilanes. Resins containing ester groups, such as PET and PC, can be hydrophobized by reacting alkylamines with the esters. In this way, when alkylamines are used, alkyl groups can be bonded to the resin through amide bonds. Furthermore, when alkylalkoxysilanes or the like are used, alkyl groups can be positioned on the resin surface by including hydroxyl groups in the resin's chemical structure.

[0044] If the number of carbon atoms in the alkyl group of the alkylamine, alkylalkoxysilane, or alkylphosphonic acid is too small, the effect of suppressing the adsorption of AMC molecules will be reduced. For this reason, it is preferable to use a material with a high carbon number, such as an alkyl group with 8 to 32 carbon atoms, and a low vapor pressure as the material for forming the SAM. Examples of alkylalkoxysilanes include alkyltrialkoxysilanes, alkylmethyldialkoxysilanes, alkylethyldialkoxysilanes, alkyldimethylmonoalkoxysilanes, and alkyldiethylmonoalkoxysilanes, which contain an alkoxy group with 1 or 2 carbon atoms and an alkyl group with 8 to 32 carbon atoms. For example, if the resin contains hydroxyl groups in its chemical structure, an alkylalkoxysilane containing an alkyl group with 8 or more carbon atoms, such as octyltrimethoxysilane, can hydrophobize the resin surface.

[0045] The surface treatment using SAM of the third embodiment can be applied in combination with the first or second embodiment. When the third embodiment is applied in combination with the first embodiment, the SAM is adsorbed onto the resin or aluminum (hydr)oxide present on the resin surface, thereby hydrophobizing the resin surface and making it more difficult for AMC molecules to adsorb. When the third embodiment is applied in combination with the second embodiment, the SAM is adsorbed onto the metal oxide film surface, thereby making it more difficult for AMC molecules to adsorb. Therefore, diffusion of AMC molecules into the resin can be more effectively suppressed. For example, when alkylphosphonic acid is used as the SAM-forming material, the alkyl group is bonded to the metal oxide, such as aluminum oxide, via a phosphonate ester bond. In the case of alkylalkoxysilane, the alkyl group is bonded to the metal oxide via a siloxane bond. These factors can more effectively suppress diffusion of AMC molecules into the resin.

[0046] As described above, when a structure having aluminum oxide, silicon oxide, or the like is formed in the first or second embodiment, molecules corresponding to these can be chemically or physically adsorbed. That is, in the case of aluminum oxide, when alkylphosphonic acid is chemically adsorbed, an alkyl group can be bonded to the aluminum oxide through the above-mentioned phosphonate ester bond, thereby forming a stable hydrophobic surface. Also, in the case of silicon oxide, when alkylalkoxysilane such as alkyltrimethoxysilane or alkylmonomethoxysilane is chemically adsorbed, an alkyl group can be bonded to the silicon oxide through a siloxane bond, thereby forming a stable hydrophobic surface. The combination of aluminum oxide and phosphonic acid is 1×10 １４ pieces / cm ２ Since the molecules can be formed at a high density, it is particularly effective in preventing the penetration of AMC molecules.

[0047] The chain length of the alkyl group of the alkyl SAM may be 8 or more carbon atoms. An alkyl group with 8 carbon atoms has a chain length of approximately 1 nm. The interaction between molecules is determined by the overlap of electron clouds (wave functions), i.e., the distance between molecules, and the interaction decays approximately exponentially. If the alkyl group chain length is less than 1 nm, it is difficult to block the influence of the surface energy of the underlying resin. Therefore, by forming a SAM using an alkylamine, alkylalkoxysilane, or alkylphosphonic acid with an alkyl group having 8 or more carbon atoms, adsorption of AMC molecules to the resin surface can be effectively prevented. It is more preferable for the alkyl group to have 12 or more carbon atoms.

[0048] It is believed that the longer the chain length of the alkyl group, if it is a straight chain, the higher the shielding effect. However, since the alkyl chain bends, it becomes difficult to achieve close packing, and as the chain length increases, the packing rate of the SAM decreases. For this reason, the upper limit for the number of carbon atoms is about 40, and 32 or less is preferable. If it is more than this, the bending effect of the alkyl chain, known in polyethylene crystals, etc., occurs, resulting in a decrease in the packing rate. In general, from the viewpoint of synthesis, a carbon number of 24 or less is preferable.

[0049] In addition, to improve the packing density of the SAM, two or more types of SAMs with different alkyl chain lengths may be mixed. For example, adsorbing an alkyl SAM with 24 carbon atoms may result in defects where the SAM does not adsorb. Adsorbing an alkyl SAM with 12 carbon atoms in this case can also prevent the occurrence of defects.

[0050] Next, examples and their evaluation results will be described.

[0051] (Example 1) A FOUP mainly composed of PC was prepared and placed in a vacuum chamber. ｘ ), followed by exposure to trimethylaluminum (TMA), a precursor of ２ A process for generating aluminum oxide by exposing the PC to TMA was carried out to attempt the formation of aluminum oxide near the surface. The temperature of exposure to TMA was varied from 100°C, 125°C, 150°C, and 175°C to form an aluminum oxide layer on the inner wall of the FOUP. The exposure time to TMA was 600 seconds.

[0052] A portion of the FOUP was cut out, and the composition distribution of elements formed on the PC surface of the FOUP inner wall was measured by X-ray photoelectron spectroscopy (XPS) using argon sputtering. Hereinafter, this method will be referred to as Ar-XPS. Figures 6A to 6D show the results of Ar-XPS analysis based on the exposure temperature to TMA. At 100°C, AlO was observed in the surface layer. ｘ A single film of AlO is formed in the PC. ｘ At 150°C, a dispersion layer (mixed layer) of AlO ｘ At 125°C, the structure was basically the same as at 150°C, and it was confirmed that the diffusion length of Al was short. These results suggest that an AlO ｘ It is thought that there is a boundary between the mode in which AlO is formed on the surface and the mode in which it is dispersed inside. ｘA "diffusion front" of Al was clearly detected even at 125°C. At 175°C, which is higher than the glass transition temperature (Tg), Al was detected to a depth of several micrometers, suggesting that the diffusion rate had increased significantly. This is a reasonable result, as molecular motion of the main chain of the polymer chain of the resin occurs above Tg. Furthermore, since there was evidence of partial melting of the PC board and numerous cracks had occurred during the shrinkage process, Tg was the upper limit temperature.

[0053] To understand the thermal properties of the PC board used as a sample, differential scanning calorimetry (DSC) and thermogravimetry (TG) were performed. The literature value for Tg of PC is 174°C, but the Tg of the PC board obtained by DSC in this study was 150°C. The difference between the Tg in this study and the literature value is thought to be due to the molecular weight of the PC. Tg reaches a constant value (literature value) at molecular weights of 100,000 or more, but decreases below that value. In addition, the thermal decomposition temperature measured by TG was 460°C. Therefore, it is thought that this PC softens above 150°C, but does not decompose due to heat up to 460°C.

[0054] DSC measurement and AlO by TMA ｘ From the results of the impregnation experiment, it was found that AlO ｘ It was confirmed that AlO can be dispersed on the PC surface. ｘ The conditions under which the film can be formed and the presence of Al(OH) ３ Regarding the conditions under which a dispersion structure of AlO can be formed on the PC surface, ｘ The process temperature when exposing the precursor is preferably 100° C. or higher and 125° C. or lower.

[0055] That is, in order to maintain the actual shape of the FOUP, it is preferable to set the process temperature to a temperature sufficiently lower than the softening temperature of the resin, and preferably to a temperature even lower than Tg at which no dimensional error of the FOUP occurs. In Example 1, dimensional fluctuations were observed at 150°C, but no dimensional fluctuations were observed at 125°C. Below Tg, it is thought that the diffusion of precursors in the resin is slow, but as mentioned above, the AlO ｘ According to the results of the impregnation experiment, AlO ｘThe upper limit of the process temperature is preferably set to 125°C, since this allows the element to be sufficiently dispersed. As a result of measuring the composition distribution of elements formed on the PC surface by Ar-XPS, it was found that at low temperatures, AlO ｘ At high temperatures, a single film of AlO ｘ At even lower temperatures, needle-like crystals were generated on the surface of the PC. These crystals could scatter inside the FOUP and become a source of contamination as dust. Therefore, it was necessary to form an AlO ｘ The conditions for forming the film and the presence of Al(OH) inside the PC ３ Regarding the conditions under which a dispersion structure of AlO can be formed on the PC surface, ｘ The lower limit of the process temperature when exposing the precursor is preferably 100°C.

[0056] (Example 2) The TMA exposure temperature was narrowed to 100 to 125°C, and the TMA pressure was changed to 100 Pa, 300 Pa, and 900 Pa, and the surface treatment of PC was carried out in the same manner as in Example 1. The exposure time to TMA was 600 seconds. For such a sample, the elemental composition in the depth direction was measured by Ar-XPS while etching with Ar.

[0057] At 125°C, the element distribution shows that C and Al coexist on the surface, and Al is dispersed in the PC. TMA diffuses into the PC in the TMA state, and then H ２ O etc., and Al(OH) ３ It is thought that TMA is converted into Al, dispersed, and fixed. The amount of Al increases as the pressure increases. At low pressure, the distribution follows a diffusion function, but at high pressure it becomes flat. This is thought to be because TMA diffuses by hopping through the carbonyl groups of PC, and is therefore determined by the density of the carbonyl groups.

[0058] 7A to 7C, 8A to 8C, and 9A to 9B show the results of Ar-XPS analysis based on the TMA exposure temperature and TMA pressure. At 110°C, AlO ｘ Based on the Ar etching time of 350 seconds, a film consisting only of AlO of about 70 nm was formed. ｘIt is presumed that a film was formed. Under this film, Al(OH) ３ A structure in which AlO was dispersed was also observed. Furthermore, a layer with a high Al concentration due to the diffusion front was observed in the deeper part. At 100°C, a TMA pressure of 300 Pa resulted in AlO on the outermost surface. ｘ A film of about 140 nm was formed equivalent to a sputtering time of 700 seconds. ｘ The layer becomes thinner and Al(OH) ３ When the pressure reached 900 Pa, the surface AlO ｘ The layer becomes thinner and Al(OH) ３ A decentralized structure was formed.

[0059] To summarize the above, aluminum (hydroxide) is composed of AlO as a protective film in order from the surface. ｘ Al(OH) as a layer, mixed layer ３ Low concentration dispersion layer of Al(OH) ３ A high concentration dispersion layer of AlO is formed as a protective film. ｘ The formation of the layer is evident in low-temperature and low-pressure TMA, but is not observed at high temperatures. Conversely, the Al(OH) ３ The Al(OH) dispersion layer tends to thicken at high temperatures. Furthermore, at a deep location, the Al concentration exceeds 20 atomic %. ３ The high concentration layer occurs under high pressure TMA conditions.

[0060] (Example 3A) As in Example 1, a FOUP containing PC as the main component was prepared. This was mixed with TMA, an aluminum precursor, and H, an oxidizing agent in an ALD chamber. ２ Film formation was carried out in ALD mode, a chemical method in which the film is exposed to O alternately (every 3 seconds) 300 times. The temperature of the FOUP during this process was set to 100°C. Since TMA easily penetrates PC, in ALD mode (sample 1), short-term exposure and oxidation were repeated, resulting in the formation of dense AlO ｘ On the other hand, in the impregnation mode (TMA impregnation mode) (Sample 2), the TMA penetrates into the PC by long-term exposure, and then AlO is formed in the PC by oxidation. ｘThese samples were subjected to Ar sputtering using Ar-XPS to observe the element distribution in the depth direction. In the ALD mode (sample 1), an AlO protective film was formed on the surface. ｘ 11A is a diagram showing the analysis results of the composition distribution of elements on the PC surface side of the FOUP inner wall of sample 1. As shown in FIG. 11A, an AlO film was formed on the PC surface side. ｘ A protective film is formed, and AlO ｘ Between the protective film and PC, AlO ｘ A mixed layer of AlO and PC was formed. ｘ The thickness of the Al film formed on the Si substrate under the same conditions was 70 nm. ２ O ３ The etching time was 180 seconds, and the thickness was 25.6 nm as measured by an ellipsometer, so the thickness on the PC was slightly thicker. ｘ It is thought that a dense structure was formed.

[0061] Example 3B: A PC-based FOUP was prepared and placed in a vacuum chamber. It was exposed to bis(ethyl-methyl-amino)silane (BEMAS), a precursor to silicon, and then to an oxidizing agent, O ３ The formation of Si oxide near the surface of PC was attempted using ALD mode, a chemical method in which exposure to BEMAS was alternately repeated 100 times (every 3 seconds). A layer of Si oxide was formed on the inner wall of the FOUP at a BEMAS exposure temperature of 140°C. A portion of the FOUP was cut out and the composition distribution of elements formed on the PC surface of the FOUP inner wall was measured using Ar-XPS. The results showed that SiO ２ A single film of SiO2 is formed in the PC. ２ A dispersed layer of

[0062] (Example 4) The catalyst obtained in Example 2 was coated with Al(OH) ３ An HF exposure test was carried out on a FOUP having an impregnated structure formed thereon. The test was carried out using the same equipment as in Example 1. The inner wall of the FOUP obtained in Example 2 was coated with Al(OH) ３A FOUP with a trap layer formed was set in the chamber and exposed to HF at a pressure of 1000 Pa for 10 minutes. These conditions represent an acceleration experiment several orders of magnitude greater than the ppb-order AMC concentration. The FOUP was removed, a portion of the FOUP was cut out, and the compositional distribution of elements formed on the PC surface of the FOUP's inner wall was measured using Ar-XPS. Figure 10A shows the analysis results of the compositional distribution of elements on the PC surface of the FOUP's inner wall before the HF exposure test, and Figure 10B shows the analysis results of the compositional distribution of elements on the PC surface of the FOUP's inner wall after the HF exposure test. Signals of Al and F were detected near the surface. In Ar-XPS, elements O, N, and F bonded or dissolved in the resin are expelled by Ar sputtering and therefore, in principle, cannot be detected. Therefore, it can be concluded that the F atoms detected in this measurement are F atoms bonded to Al. As described above, the Al(OH) formed in the resin ３ It was confirmed that HF ​​was trapped.

[0063] (Example 5) The inner wall obtained in Example 3 was coated with AlO ｘ An HF exposure test was carried out on the FOUP on which the film was formed. The test was carried out using the same equipment as in Example 1. ｘ The FOUP on which the film was formed was set and exposed to HF at a pressure of 2500 Pa for 10 minutes. The FOUP was removed, a portion of the FOUP was cut out, and the composition distribution of elements formed on the PC surface of the FOUP inner wall was measured by Ar-XPS. Figure 11A shows the analysis results of the composition distribution of elements on the PC surface side of the FOUP inner wall before the HF exposure test. As shown in Figure 11A, AlO ｘ A protective film is formed, and AlO ｘ Between the protective film and PC, AlO ｘ A mixed layer of AlO and PC was formed. Figure 11B shows the analysis results of the elemental composition distribution on the PC surface side of the FOUP inner wall after the HF exposure test. F signals were detected only within a few nanometers of the surface. Most of the AlO Ｘ (Al ２ O ３ No F was detected in the AlO Ｘ Since a dense film of Al is formed, O is replaced by F only on the top surface of Al, but AlOｘ This indicates that HF ​​did not penetrate into the interior of the membrane.

[0064] As described above, AlO formed on the resin surface Ｘ It was confirmed that the film functions as a protective film that blocks HF. In addition, F atoms were detected only near the surface and did not penetrate into the interior, which indicates that 100 exposures in Example 3 is sufficient.

[0065] (Example 6) A FOUP mainly composed of PC was prepared and placed in a vacuum chamber. ｘ ), followed by exposure to trimethylaluminum (TMA), a precursor of ２ In this process (impregnation mode), a process of generating aluminum oxide by exposing the PC to TMA was carried out to attempt the formation of aluminum oxide near the surface. The temperature of exposure to TMA was set to 100°C, and an aluminum oxide layer was formed on the inner wall of the FOUP. The exposure time to TMA was set to 600 seconds. In this process (impregnation mode), the PC was penetrated into the interior by long-term exposure to TMA alone, and then oxidized to form AlO ｘ Furthermore, without removing it from the chamber, TMA, an aluminum precursor, and H, an oxidizing agent were added. ２ The film was formed in ALD mode, a chemical method that alternately exposes the substrate to O (every 3 seconds) 150 times. In ALD mode, the repeated short-term exposure and oxidation create a dense AlO ｘ It forms a film easily.

[0066] Figure 12 shows the results of observing the depth distribution of elements in the obtained sample using Ar-XPS while Ar sputtering. As shown in Figure 12, AlO ｘ A strong protective film consisting of Al(OH) was formed. The protective film is expected to prevent the penetration of AMC. Furthermore, a mixed layer in which the concentration of Al decreases in a gradient was formed. This layer differs from ceramic films formed on resin by physical film formation such as ordinary vapor deposition or sputtering, in that the resin and protective film materials are mixed together and act as an adhesive layer, preventing the protective film from peeling off. Furthermore, underneath it, Al(OH) ３There is a layer of resin with a dispersion structure of AMC. Even if AMC passes through the protective film, it will be trapped and fixed here in the dispersion structure layer. Although it is not shown in the figure, there is a layer of resin only below the dispersion structure.

[0067] Such a structure having both a protective film and a dispersion structure has the blocking ability of the protective film and the trapping ability of the dispersion structure intact, and therefore has a very high AMC penetration prevention effect and diffusion prevention property.

[0068] Example 7 In Example 7, a surface treatment using SAM was performed. A FOUP containing PC as the main component was prepared. 1 mL of octadecyltrimethoxysilane was placed in a petri dish, which was then placed inside the FOUP and sealed. After 24 hours, the octadecyltrimethoxysilane was removed. The sample in which octadecyltrimethoxysilane was reacted with the inner wall of the FOUP was designated Sample A.

[0069] A 5% by mass solution of dodecylamine in ethanol was prepared. This solution was poured into a FOUP, which was then sealed. The entire FOUP was then heated to 60°C and left for 30 minutes. After the dodecylamine ethanol solution was drained, the FOUP was rinsed twice with ethanol and then washed with water. This was designated Sample B.

[0070] A 1% by mass ethanol solution of octadecylamine was prepared. This solution was poured into a FOUP, which was then sealed. The entire FOUP was then heated to 70°C and left for 30 minutes. After the ethanol solution of octadecylamine was drained, the FOUP was rinsed twice with ethanol and then washed with water. This was designated Sample C.

[0071] The water contact angles of the inner walls of these FOUPs were measured. The water droplet contact angle of the untreated sample was 90°, while the water droplet contact angle of Sample A was 98.5°, the water droplet contact angle of Sample B was 125.8°, and the water droplet contact angle of Sample C was 99.5°. It can be seen that the hydrophobicity of the surface of each sample increased after treatment.

[0072] Next, an HF exposure test was conducted on the FOUP with the treated inner wall. The test was conducted using the same equipment as in Example 4. A portion of the PC was cut out after the exposure test, and the elemental composition of the outermost surface was observed using XPS. As a result, the F atom content on the resin surface of the untreated sample was 21 atomic %. In contrast, the F element content of Sample A was 5.2 atomic %, Sample B was 1.2 atomic %, and Sample C was 3.2 atomic %. It was confirmed that surface treatment using SAM on the resin surface made the surface hydrophobic and reduced the amount of adsorption of the highly polar F element.

[0073] (Example 8) The resin prepared in Example 2 was coated with Al(OH) ３ This was designated as Sample D. In addition, a FOUP having a surface layer of AlO ｘ A FOUP on which a film was formed was prepared. This was designated Sample E. The water contact angles of the inner walls of these FOUPs were measured. The water droplet contact angle of Sample D was 87.2°, and the water droplet contact angle of Sample E was 87.9°.

[0074] Next, a solution of octadecylphosphonic acid dissolved in ethanol at a concentration of 10 mmol / L was prepared. This solution was poured into the FOUPs of Samples D and E, which were then sealed, and the entire FOUP was left at room temperature for 60 minutes. After draining the ethanol solution of octadecylphosphonic acid, the FOUPs were rinsed twice with ethanol and then washed with water. These were designated Samples F and G.

[0075] The water contact angles of the inner walls of these FOUPs were measured. The water droplet contact angle for Sample F was 103.8°, and the water droplet contact angle for Sample G was 107.7°. It can be seen that the hydrophobicity of the surface of both samples increased after treatment. This is because octadecylphosphonic acid forms a strong chemical bond with the outermost surface of the aluminum oxide. Even in the case of aluminum oxide impregnated near the resin surface, if the hydroxyl groups bonded to the aluminum are exposed on the surface, the phosphonic acid will chemically bond.

[0076] Next, an HF exposure test was conducted on the FOUP with the treated inner wall. The test was conducted using the same equipment as in Example 4. A portion of the PC was cut out after the exposure test, and the elemental composition of the outermost surface was observed using XPS. As a result, the F atoms on the surface of untreated Sample D were 25.5 atomic %, and the F atoms on the surface of Sample E were 48.3 atomic %. In contrast, the F atoms on the surface of Sample F were 4.2 atomic %, and the F atoms on the surface of Sample G were 1.2 atomic %. It was confirmed that the SAM made the inner wall surface of the FOUP hydrophobic, making it less susceptible to adsorption of the highly polar HF element.

[0077] The hydrophobic layer formed on an aluminum oxide film using a phosphonic acid SAM can be regenerated using the following method. For accelerated experiments, the surface on which the hydrophobic layer was formed was irradiated with UV light, and the hydrophobic layer was then removed. In this state, the water droplet contact angle on the surface of Sample F was 89.2°, and the water droplet contact angle on the surface of Sample G was 88.8°. The inner walls of the samples were hydrophobized using the same method as the first time. The water droplet contact angle for Sample F was 105.6°, and the water droplet contact angle for Sample G was 107.8°. This demonstrates that even if the hydrophobic layer deteriorates, it can be regenerated any number of times.

[0078] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0079] 1...semiconductor wafer transport container (FOUP), 2...resin container body, 3...front opening, 4...resin door portion, 5...resin container, 6...wafer support portion, 7...gas outlet port.

Claims

1. A semiconductor wafer transport container having a resin container for storing semiconductor wafers, A semiconductor wafer transport container, in which an aluminum oxide having a hydroxyl group is impregnated near the surface of the resin on at least the inner surface of the resin container, and a structure in which the aluminum oxide is dispersed in the resin at a concentration of 1 atomic % or more in terms of an aluminum element concentration exists at least within a range of a depth from the inner surface of 50 nm to 10 μm.

2. 2. The semiconductor wafer transport pod according to claim 1, wherein a structure is present in which the aluminum oxide is dispersed in the resin at a concentration of 5 atomic % to 30 atomic %, calculated as an aluminum element concentration, within a range of 50 nm to 10 μm deep from the inner surface.

3. 2. The semiconductor wafer transport pod according to claim 1, wherein a metal oxide film having a thickness of 20 nm to 1 μm is formed on the inner surface of the resin container impregnated with the aluminum oxide.

4. 4. The semiconductor wafer transport pod according to claim 3, wherein the metal oxide includes at least one selected from the group consisting of aluminum oxide, silicon oxide, and zirconium oxide.

5. 2. The semiconductor wafer transport container according to claim 1, wherein a self-assembled monolayer containing an alkyl group having 8 to 32 carbon atoms is provided on the inner surface of the resin container impregnated with the aluminum oxide.

6. A semiconductor wafer transport container having a resin container for storing semiconductor wafers, a metal oxide film containing a metal oxide is formed on at least an inner surface of the resin container containing a resin, and a mixed layer of the resin and the metal oxide is formed between the resin and the metal oxide, The metal oxide comprises at least one selected from the group consisting of aluminum oxide, silicon oxide, and zirconium oxide.

7. 7. The semiconductor wafer transport pod according to claim 6, wherein the metal oxide film has a thickness of 20 nm to 1 μm, and the mixed layer has a thickness of 10 nm to 1 μm.

8. 7. The semiconductor wafer transport container according to claim 6, wherein a self-assembled monolayer containing an alkyl group having 8 to 32 carbon atoms is provided on the inner surface of the resin container on which the metal oxide film is formed.

9. 9. The semiconductor wafer transport container according to claim 8, wherein the metal oxide comprises aluminum oxide, and the self-assembled monolayer has the alkyl group bonded to the aluminum oxide by a phosphonate ester.

10. 9. The semiconductor wafer transport pod according to claim 8, wherein the metal oxide includes silicon oxide, and the self-assembled monolayer has the alkyl group bonded to the silicon oxide through a siloxane bond.

11. A semiconductor wafer transport container having a resin container for storing semiconductor wafers, A semiconductor wafer transport vessel, wherein at least the inner surface of the resin vessel is provided with a self-assembled monolayer containing an alkyl group having 8 to 32 carbon atoms.

12. 2. A method for manufacturing the semiconductor wafer transport pod according to claim 1, comprising the steps of: exposing at least the inner surface of the resin container to an alkyl aluminum under reduced pressure to impregnate the resin with the alkyl aluminum; exposing at least the inner surface of the resin container to an oxidizing agent selected from water, ozone, and plasma oxygen to oxidize the alkyl aluminum impregnated in the resin; A method for manufacturing a semiconductor wafer transport pod comprising the steps of:

13. 13. The method of claim 12, wherein the step of exposing to alkyl aluminum is carried out under a reduced pressure of 10 Pa to 5 kPa inclusive of partial pressure of alkyl aluminum for 30 seconds to 1 hour inclusive.

14. 14. The method for manufacturing a semiconductor wafer transport pod according to claim 13, further comprising the step of forming a metal oxide film on at least the inner surface of the resin container which has been subjected to the step of exposing to the alkyl aluminum and the step of exposing to the oxidizing agent.

15. 13. The method for manufacturing a semiconductor wafer transport container according to claim 12, further comprising a step of providing a self-assembled monolayer containing an alkyl group by using at least one selected from an alkylamine, an alkylphosphonic acid, and an alkylalkoxysilane, each having an alkyl group having 8 to 32 carbon atoms, on at least an inner surface of the resin container which has been subjected to the alkylaluminum exposure step and the oxidizing agent exposure step.

16. 7. A method for manufacturing a semiconductor wafer transport pod according to claim 6, comprising the steps of: exposing at least the inner surface of the resin container to at least one selected from an alkyl metal, an alkoxy metal, and an alkylamino metal under a pressure of 1 Pa to 300 Pa for 1 second to 10 seconds; and exposing at least the inner surface of the resin container to at least one oxidizing agent selected from water, ozone, and plasma oxygen. A method for manufacturing a semiconductor wafer transport container, comprising repeating the step of exposing to at least one selected from alkyl metals, alkoxy metals, and alkylamino metals and the step of exposing to an oxidizing agent 10 to 1,000 times to form the metal oxide film.

17. 17. The method of manufacturing a semiconductor wafer transport pod according to claim 16, wherein the alkyl metal, alkoxy metal, or alkylamino metal contains at least one metal selected from the group consisting of aluminum, silicon, and zirconium.

18. 17. The method for manufacturing a semiconductor wafer transport container according to claim 16, further comprising a step of providing a self-assembled monolayer containing an alkyl group on the metal oxide film formed on at least the inner surface of the resin container by repeatedly performing the step of exposing to the alkyl metal, alkoxy metal, or alkylamino metal and the step of exposing to the oxidizing agent, using at least one selected from an alkylphosphonic acid and an alkylalkoxysilane having an alkyl group having 8 to 32 carbon atoms.

19. A method for manufacturing the semiconductor wafer transport pod according to claim 11, comprising the steps of: A method for manufacturing a semiconductor wafer transport container, comprising a step of forming a self-assembled monolayer containing an alkyl group on at least the inner surface of the resin container using at least one selected from alkylamines, alkylphosphonic acids, and alkylalkoxysilanes, each having an alkyl group having 8 to 32 carbon atoms.