A polycycloolefinic material and its use in wafer boxes

Abstract

The application provides a polycycloolefin material and its application in wafer boxes, and a preparation method of the polycycloolefin material comprises the following steps: mixing a polycycloolefin resin, a monomer containing a polar functional group and an initiator to perform reactive extrusion grafting, so as to obtain a functionalized polycycloolefin base; melt blending the functionalized polycycloolefin base, two-dimensional sheet conductive fillers with an addition amount of 0.05% to 0.4% and one-dimensional tubular conductive fillers with an addition amount of 0.01% to 0.15%, so as to obtain composite material granules; and injection molding the composite material granules at an injection speed of greater than or equal to 120 mm / s, and controlling the mold temperature to be 75 DEG C to 80 DEG C and the near-wall cooling rate to be 50 DEG C / min to 200 DEG C / min. The polycycloolefin material and the wafer box prepared by the preparation method can realize the synergistic improvement of antistatic property, rapid charge decay and high gas barrier property under the condition of ultra-low filler amount.

Description

Technical Field

[0001] This application relates to the field of polymer composite materials technology, and in particular to a polycyclic olefin material and its application in wafer cassettes. Background Technology

[0002] In recent years, as semiconductor manufacturing processes have advanced to nodes of 3nm and below, the requirements for the cleanliness and stability of the container environment during the transport and storage of wafers and photomasks have become increasingly stringent. In advanced processes such as EUV lithography, even minute electrostatic discharges can cause circuit damage or particle adsorption, while the humidity level inside the wafer housing directly affects photomask fogging and wafer surface oxidation. Therefore, the main material of the wafer housing must simultaneously possess excellent antistatic properties, ultra-low water vapor transmission rate, and the ability to rapidly dissipate charge.

[0003] Existing technologies typically employ the addition of graphene materials to cyclic olefin copolymers or polymers to achieve antistatic properties. However, single-dimensional graphene sheets are prone to recombination in non-polar matrices, resulting in limited dispersion efficiency and a relatively high percolation threshold, making it difficult to further reduce the amount of carbon material used. Simultaneously, the weak interfacial bonding between the unmodified matrix and the filler limits the retention of dispersion quality and mechanical properties. Furthermore, pure two-dimensional sheets exhibit poor outward conductivity after orientation, leading to slow charge conduction from the surface to the grounding point, thus limiting antistatic effectiveness.

[0004] Therefore, it is necessary to provide a polycyclic olefin material and its application in wafer cassettes. Summary of the Invention

[0005] This application is made in view of the above-mentioned technical problems, and one of its objectives is to provide a method for preparing a polycyclic olefin material with low carbon material content and synergistic improvement in antistatic, barrier and charge decay properties, and correspondingly provide a polycyclic olefin material and its application in wafer cassettes.

[0006] To achieve the above objectives, a first aspect of this application provides a method for preparing a polycyclic olefin material, comprising: mixing a polycyclic olefin resin with a monomer containing polar functional groups and an initiator, and performing reactive extrusion grafting to obtain a functionalized polycyclic olefin matrix; melt-blending the functionalized polycyclic olefin matrix with a two-dimensional sheet conductive filler and a one-dimensional tubular conductive filler to obtain composite material granules, wherein the amount of the two-dimensional sheet conductive filler added is 0.05% to 0.4% of the total weight of the composite material, and the amount of the one-dimensional tubular conductive filler added is 0.01% to 0.15% of the total weight of the composite material; and injection molding the composite material granules, controlling the injection speed to be ≥120 mm / s, the mold temperature to be 75℃ to 80℃, and the near-wall cooling rate to be 50℃ / min to 200℃ / min.

[0007] Through the above preparation method, reactive extrusion grafting introduces monomers containing polar functional groups into the matrix backbone. These polar sites form hydrogen bonds or dipole interactions with the oxygen-containing functional groups on the surface of the carbon-based filler, significantly improving the wettability and dispersibility of the filler in the melt. Based on this, a hybrid system is constructed by introducing one-dimensional tubular conductive fillers and two-dimensional sheet-like conductive fillers. The one-dimensional tubular fillers act as conductive bridges between adjacent two-dimensional sheets, connecting isolated two-dimensional conductive islands into a complete network, generating a synergistic percolation effect. This allows the conductive network to form at concentrations far below the percolation threshold of a single filler, thereby significantly reducing the total amount of carbon filler and mitigating the degradation of the matrix toughness. During the injection molding stage, a high injection speed of ≥120 mm / s generates a strong shear field near the mold cavity wall, driving the high aspect ratio two-dimensional sheets to align parallel to the flow direction. The low mold temperature of 75℃~80℃ combined with a high cooling rate of 50℃ / min~200℃ / min rapidly solidifies the melt near the wall, effectively freezing the parallel orientation configuration of the two-dimensional sheets. This orientation enhances the continuity of the in-plane conductive path, while forming a highly tortuous labyrinthine path in the out-of-plane direction of water vapor permeation, significantly reducing water vapor transmission rate. Meanwhile, the one-dimensional tubular packing, with its flexible structure, maintains a random or out-of-plane distribution, providing out-of-plane conductive bridges between the oriented two-dimensional sheets, compensating for the decrease in out-of-plane conductivity caused by the orientation, thereby achieving a simultaneous improvement and synergy in antistatic and gas barrier properties.

[0008] In any embodiment, the amount of the monomer containing polar functional groups is controlled such that the grafting rate of polar functional groups in the functionalized polycyclic olefin matrix is ​​0.3 mol% to 2.0 mol%. This provides sufficient polar anchors to improve filler dispersion while maintaining the non-polar bulk characteristics and low hygroscopicity of the matrix. Understandably, the grafting rate can be 0.3 mol%, 0.5 mol%, 1.0 mol%, 1.5 mol%, 2.0 mol%, or any value within the range formed by any two of the above values.

[0009] In any embodiment, the polar functional group is selected from at least one polar functional group selected from maleic anhydride, carboxyl, and hydroxyl groups. This allows for effective interfacial interaction with the carbon-based filler surface, improving dispersion uniformity.

[0010] In any embodiment, the polycyclic olefin resin is selected from at least one of cyclic olefin copolymers, cyclic olefin polymers, and cyclic block copolymers. Thus, this preparation method is applicable to the family of cyclic olefin polymers and has broad applicability.

[0011] In any embodiment, the two-dimensional sheet conductive filler includes at least one of graphene nanosheets and reduced graphene oxide; the one-dimensional tubular conductive filler includes multi-walled carbon nanotubes. Thus, by utilizing the large-area in-plane conductivity and barrier properties of graphene nanosheets, and the efficient interlayer bridging function of multi-walled carbon nanotubes, functional division and complementarity are achieved.

[0012] In any embodiment, the screw speed for the reactive extrusion grafting is 150 rpm to 250 rpm, and the residence time is 1 min to 3 min. This provides sufficient reaction shear and mixing time to ensure uniform grafting of polar functional groups.

[0013] In any embodiment, the melt blending temperature is 210℃~260℃, and the injection molding melt temperature is 270℃~280℃. This ensures sufficient melting of the matrix and dispersion of the filler while avoiding matrix degradation due to excessively high temperatures.

[0014] The second aspect of this application provides a polycyclic olefin material prepared by the method of the first aspect of this application. This polycyclic olefin material, with a total carbon filler content of less than 0.6 wt%, exhibits excellent antistatic properties, rapid charge decay capability, significant water vapor barrier properties, and good mechanical toughness.

[0015] A third aspect of this application provides a wafer cassette, including a housing comprising the polycyclic olefin material of the second aspect of this application. This wafer cassette effectively prevents electrostatic discharge damage and particle adsorption, and maintains a low-humidity environment inside the housing for extended periods.

[0016] In any embodiment, the wafer cassette is a front-opening wafer transfer cassette or a photomask transfer cassette. This is suitable for the storage and transfer needs of different precision substrates in advanced semiconductor processes.

[0017] This application provides a polycyclic olefin material and its application in wafer cassettes. The preparation method of the polycyclic olefin material includes: mixing a polycyclic olefin resin with a monomer containing polar functional groups and an initiator, and then performing reactive extrusion grafting to obtain a functionalized polycyclic olefin matrix; melt-blending the functionalized polycyclic olefin matrix with 0.05%–0.4% of a two-dimensional sheet-like conductive filler and 0.01%–0.15% of a one-dimensional tubular conductive filler to obtain composite material granules; and injection molding the composite material granules at an injection speed of ≥120 mm / s, controlling the mold temperature at 75℃–80℃ and the near-wall cooling rate at 50℃ / min–200℃ / min. The polycyclic olefin material and wafer cassette prepared by this method can achieve a synergistic improvement in antistatic properties, rapid charge decay, and high gas barrier properties with ultra-low filler content. Detailed Implementation

[0018] The present application will be further described in detail below with reference to the embodiments and examples. It should be understood that these embodiments and examples are for illustrative purposes only and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to enable a more thorough and comprehensive understanding of the disclosure of the present application. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0019] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0020] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings: The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical AND," and also undoubtedly includes technical solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0021] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0022] In any embodiment, the amount of the monomer containing polar functional groups is controlled such that the grafting rate of polar functional groups in the functionalized polycyclic olefin matrix is ​​0.3 mol% to 2.0 mol%. Controlling the grafting rate within this range allows for the provision of sufficient polar anchors to improve filler dispersion while maintaining the non-polar bulk characteristics and low hygroscopicity of the matrix. Understandably, the grafting rate can be 0.3 mol%, 0.5 mol%, 0.8 mol%, 1.0 mol%, 1.2 mol%, 1.5 mol%, 1.8 mol%, 2.0 mol%, or any value within the range formed by any two of the above values.

[0023] In any embodiment, the amount of the two-dimensional sheet conductive filler added is 0.05% to 0.4% of the total weight of the composite material. Controlling the amount of the two-dimensional sheet conductive filler within this range allows for the formation of in-plane conductive pathways and gas-barrier labyrinth paths while avoiding dispersion difficulties and reduced toughness due to excessive addition. Understandably, the addition amount can be 0.05%, 0.08%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, or any value within the range formed by any two of the above values.

[0024] In any embodiment, the amount of the one-dimensional tubular conductive filler added is 0.01% to 0.15% of the total weight of the composite material. In this way, the one-dimensional tubular filler can provide sufficient out-of-plane conductive bridges between the two-dimensional layers, achieving synergistic filtration. It is understood that the amount added can be 0.01%, 0.03%, 0.05%, 0.08%, 0.10%, 0.12%, 0.15%, or any value within the range formed by any two of the above values.

[0025] In any embodiment, the injection speed is controlled to be ≥120 mm / s. A higher injection speed can generate a strong shear field near the mold cavity wall, driving the two-dimensional sheets to align parallel to the flow direction. Understandably, the injection speed can be 120 mm / s, 130 mm / s, 150 mm / s, 180 mm / s, 200 mm / s, or any value within the range formed by any two of the above values.

[0026] In any embodiment, the mold temperature is 75°C to 80°C. A lower mold temperature facilitates rapid cooling and freezing of the orientation configuration of the two-dimensional sheets. Understandably, the mold temperature can be 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, or any value within the range formed by any two of the above values.

[0027] In any embodiment, the near-wall cooling rate is 50°C / min to 200°C / min. The high cooling rate allows the near-wall melt to solidify rapidly, ensuring the effective preservation of the orientation structure. Understandably, the near-wall cooling rate can be 50°C / min, 80°C / min, 100°C / min, 120°C / min, 150°C / min, 180°C / min, 200°C / min, or any value within the range formed by any two of the above values. The "near-wall cooling rate" as used in this application is defined as: the average rate of temperature decrease of the polymer melt within a depth of 0.5 mm from the mold cavity wall during injection molding, from the injection melt temperature (Tm) to the glass transition temperature (Tg) of the matrix resin.

[0028] The calculation formula is: Near-wall cooling rate V = (Tm - Tg) / t Where: V is the near-wall cooling rate, in °C / min; Tm is the set melt temperature of the injection molding machine barrel, in °C; Tg is the glass transition temperature of the pure matrix resin without fillers, in °C, determined by differential scanning calorimetry (DSC) according to GB / T 19466.2; t is the time required from the moment the melt fills the mold cavity until the near-wall melt temperature drops to Tg, in min.

[0029] The method for measuring t is as follows: a microhole with a depth of 0.5 mm is machined on the wall of the mold cavity, and a miniature thermocouple (K type or J type) with a diameter ≤ 0.5 mm is embedded. The time when the mold filling is completed is recorded as the starting point, and the time when the thermocouple temperature drops to Tg is recorded as the ending point. The time difference t is then calculated.

[0030] Example 1: This example provides a polycyclic olefin material and its application in wafer cassettes.

[0031] (1) Functional modification of COP (reactive extrusion grafting) Cyclic olefin polymer (COP, Tg=140℃, MFR=15 g / 10min) resin particles were vacuum dried at 80℃ for 4 h. 100 parts of the dried COP particles, 1.5 parts of maleic anhydride (MAH), and 0.3 parts of dicumyl peroxide (DCP) were premixed in a high-speed mixer for 3 min. The premixed material was added to a co-rotating twin-screw extruder (screw diameter φ35 mm, L / D ratio L / D=40) for reactive extrusion grafting: the temperature range was set as follows: feed section 200℃, reaction section 240℃, metering section 250℃, die head 245℃; screw speed 200 rpm; residence time approximately 2 min. The extruded strip was water-cooled and pelleted. The pelleted material was refluxed with acetone for 8 h to remove unreacted MAH and DCP residues. After vacuum drying, the grafting rate was determined to be 1.0 mol%, yielding a functionalized cyclic olefin polymer matrix (MAH-g-COP).

[0032] (2) Preparation of hybrid filler masterbatch (melt blending) The matrix consisted of 99.75 wt% MAH-g-COP and graphene nanosheets (GNP, with lateral dimensions of 10–25 μm, thickness of 3–8 nm, and specific surface area of ​​300–500 m²). 2 GNP (g) 0.20 wt% and multi-walled carbon nanotubes (MWCNT, outer diameter 8-15 nm, length 5-15 μm, purity ≥99.5%) 0.05 wt% were first pre-dispersed in a small amount of MAH-g-COP powder at a mass ratio of 20:1. The mixture was then dry-mixed in a high-speed mixer for 5 min. The mixture was then added together with the remaining MAH-g-COP matrix to a co-rotating twin-screw extruder. The temperature range was set as follows: feed section 210℃, mixing section 250℃, metering section 260℃, die head 255℃; screw speed 250 rpm; and a reverse screw element was set to enhance dispersion and mixing. The extruded strip was water-cooled and pelletized to obtain composite material granules.

[0033] (3) Injection-molded wafer boxes The composite material granules were vacuum dried at 80℃ for 4 hours. The open-faced wafer pod (FOUP) shell was formed using an injection molding machine: melt temperature 270℃; mold temperature 75℃; injection speed 150 mm / s; holding pressure 60 MPa; holding time 8 s; cooling time 25 s. Under this process, the near-wall cooling rate was 120℃ / min.

[0034] Example 2: This example is basically the same as Example 1, except that: In step (1), cyclic olefin copolymer (COC, Tg=170℃) is used to replace COP, and the amount of MAH and DCP is controlled so that the final grafting rate is 0.5 mol%; in step (2), the content of MAH-g-COC matrix is ​​99.77 wt%, the content of GNP is 0.15 wt% (transverse dimension 15~25 μm), and the content of MWCNT is 0.08 wt%; in step (3), the melting temperature is 280℃, the injection speed is 180 mm / s, the mold temperature is 80℃, and the near-wall cooling rate is 150℃ / min.

[0035] Example 3: This example is basically the same as Example 1, except that: In step (1), cyclic block copolymer (CBC) is used to replace COP, and the amount of MAH and DCP is controlled so that the final grafting rate is 1.5 mol%; in step (2), the content of MAH-g-CBC matrix is ​​99.67 wt%, and the content of reduced graphene oxide (rGO) obtained by thermal reduction of few-layer graphene oxide is 0.30 wt%, and the content of MWCNT is 0.03 wt%; in step (3), the injection speed is 120 mm / s, the mold temperature is 75℃, and the near-wall cooling rate is 100℃ / min; the molded part is the photomask transfer box shell.

[0036] Example 4: This example is basically the same as Example 1, except that: In step (1), the amount of MAH and DCP fed is controlled so that the final grafting rate of MAH-g-COP is 0.3 mol.

[0037] Example 5: This example is basically the same as Example 1, except that: In step (2), the content of MAH-g-COP matrix is ​​99.94 wt%, the content of GNP is 0.05 wt%, and the content of MWCNT is 0.01 wt%.

[0038] Example 6: This example is basically the same as Example 2, except that: In step (1), acrylic acid is used to replace maleic anhydride to provide carboxyl groups as monomers containing polar functional groups. The amount of acrylic acid and initiator is controlled so that the carboxyl grafting rate of the final functionalized COC is 0.8 mol.

[0039] Example 7: This example is basically the same as Example 1, except that: In step (1), the screw speed for reactive extrusion grafting is 150 rpm and the residence time is 3 min.

[0040] Example 8: This example is basically the same as Example 1, except that: In step (3), the injection speed is 200 mm / s, and the cooling system is controlled to make the near-wall cooling rate 200℃ / min.

[0041] Comparative Example 1: This comparative example is basically the same as Example 1, except that in step (2), the content of MAH-g-COP matrix is ​​99.80 wt%, only 0.20 wt% GNP is used as conductive filler, and multi-walled carbon nanotubes (MWCNTs) are not added.

[0042] Comparative Example 2: This comparative example is basically the same as Example 1, except that: in step (1), ordinary COP resin without grafting is used for direct granulation; in step (2), the content of ordinary COP matrix is ​​99.75 wt%, the content of GNP is 0.20 wt%, and the content of MWCNT is 0.05 wt%.

[0043] Comparative Example 3: This comparative example directly uses 99.00 wt% of ungrafted ordinary COP resin and 1.00 wt% of GNP for melt blending (excluding MWCNT), and is molded under standard injection molding conditions (injection speed 100 mm / s, mold temperature 90℃, near-wall cooling rate of about 40℃ / min).

[0044] The materials prepared above were tested.

[0045] Surface resistance testing method: Refer to ASTM D257 standard and use a high-resistivity meter (such as Keithley 6517B) with concentric ring electrodes. Cut a 100mm×100mm sample from the planar area of ​​the injection-molded shell. After adjusting to a temperature of 23±2℃ and a relative humidity of 50±5%RH, test at least 5 different locations for each sample and take the average value as the surface resistance value.

[0046] Water vapor transmission rate (WVTR) test method: Refer to ASTM F1249 (infrared sensor method). Cut a circular sample (diameter ≥70 mm) with the same thickness as the actual wall thickness from the injection-molded shell. Test conditions are: temperature 38±1℃, relative humidity 90±2%RH on one side of the sample, and 0%RH on the other side. Record the WVTR value and calculate the percentage reduction in WVTR relative to the pure matrix material (same molding process).

[0047] Electrostatic charge decay time test method: Refer to IEC 61340-2-1 standard and use an electrostatic charge decay tester. Cut a sample from the planar area of ​​the injection molded shell. Under the conditions of temperature 23±2℃ and relative humidity 12±3%RH, apply an initial voltage of ±1000 V to the sample surface and record the time required for the voltage to decay to 100 V. Take the average value of 5 measurements.

[0048] Impact strength test method: Refer to ISO 180:2023 (cantilever beam impact strength, Izod method, with notch), cut standard test strips from the injection molded part according to the standard or inject them separately, test at a temperature of 23±2℃, and record the impact strength value.

[0049] Table 1 Test results of the examples and comparative examples

[0050]

[0051] Table 2 Performance test results of each embodiment and comparative example

[0052]

[0053] As shown in Tables 1 and 2, the polycyclic olefin materials prepared in each embodiment of this application can achieve a surface resistivity of 10 Ω·cm under the condition that the total carbon filler content is less than 0.6 wt%. 9 ~10 11 The material exhibits an antistatic rating of Ω / sq, significantly reduced water vapor permeability, and extremely short charge decay time, while maintaining good impact resistance. This indicates that the preparation method described in this application achieves a comprehensive balance of antistatic properties, barrier properties, and mechanical properties at ultra-low filler content through the synergistic effect of matrix functionalization, hybrid filler system, and injection molding orientation control.

[0054] Comparing Example 1 and Comparative Example 1, it can be seen that after removing the one-dimensional tubular conductive filler MWCNT (Comparative Example 1), 0.20 wt% of two-dimensional GNP alone cannot form a continuous conductive network, and the surface resistivity rises sharply to 10 Ω·cm. 13 When the charge decay time exceeds 60 s, the antistatic function is completely lost. Simultaneously, due to the lack of auxiliary dispersion and bridging by MWCNTs, the continuity of the barrier labyrinth path of GNP deteriorates, and the WVTR reduction rate decreases from 40% to 28%. This demonstrates that one-dimensional tubular packings have an irreplaceable synergistic effect in hybrid systems for reducing the percolation threshold, constructing a three-dimensional conductive network, and ensuring the continuity of the barrier path.

[0055] Comparing Example 1 and Comparative Example 2, it can be seen that when the matrix functionalization is removed (Comparative Example 2), the interfacial bonding force between the nonpolar COP matrix and GNP and MWCNT is weak. The fillers are unevenly dispersed and agglomerate during melt blending, resulting in an increased percolation threshold and a deterioration of the surface resistivity to 8×10⁻⁶. 12 The charge decay time was extended to 8.0 s, the WVTR reduction rate was only 18%, and interfacial agglomeration led to a decrease in impact strength to 36 J / m. This proves that matrix functionalization is an enabling prerequisite for hybrid fillers to exert a synergistic effect, and the improvement of interfacial wetting and dispersion quality by polar anchor points directly determines the final electrical and barrier properties.

[0056] Comparing Example 1 and Comparative Example 3, it can be seen that Comparative Example 3 adopted the existing technical solution and used 4 times the amount of carbon filler (1.0 wt% GNP), although it achieved the antistatic grade (5×10). 10While its WVTR reduction rate was only 12%, the charge decay time was as long as 12.0 s, and the impact strength dropped to 34 J / m. This is because the high filler content led to increased agglomeration, and without orientation optimization and three-dimensional bridging, the random distribution of two-dimensional sheets could not construct an efficient out-of-plane barrier labyrinth and out-of-plane conductive channels. This application achieves significant performance improvements in all aspects with only 1 / 4 of the filler content.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a polycyclic olefin material, comprising: A polycyclic olefin resin is mixed with a monomer containing polar functional groups and an initiator, and then subjected to reactive extrusion grafting to obtain a functionalized polycyclic olefin matrix. The functionalized polycyclic olefin matrix is ​​melt-blended with two-dimensional sheet-like conductive fillers and one-dimensional tubular conductive fillers to obtain composite material granules, wherein the amount of the two-dimensional sheet-like conductive filler added is 0.05% to 0.4% of the total weight of the composite material, and the amount of the one-dimensional tubular conductive filler added is 0.01% to 0.15% of the total weight of the composite material. The composite material granules are injection molded with an injection speed of ≥120 mm / s, a mold temperature of 75℃~80℃, and a near-wall cooling rate of 50℃ / min~200℃ / min.

2. The method for preparing the polycyclic olefin material according to claim 1, characterized in that, The amount of the monomer containing polar functional groups is controlled such that the grafting rate of polar functional groups in the functionalized polycyclic olefin matrix is ​​0.3 mol% to 2.0 mol%.

3. The method for preparing polycyclic olefin materials according to claim 1, characterized in that, The polar functional group is selected from at least one polar functional group selected from maleic anhydride, carboxyl and hydroxyl groups.

4. The method for preparing polycyclic olefin materials according to claim 1, characterized in that, The polycyclic olefin resin is selected from at least one of cyclic olefin copolymers, cyclic olefin polymers, and cyclic block copolymers.

5. The method for preparing polycyclic olefin materials according to claim 1, characterized in that, The two-dimensional sheet conductive filler includes at least one of graphene nanosheets and reduced graphene oxide; the one-dimensional tubular conductive filler includes multi-walled carbon nanotubes.

6. The method for preparing the polycyclic olefin material according to claim 1, characterized in that, The screw speed for the reactive extrusion grafting is 150 rpm to 250 rpm, and the residence time is 1 min to 3 min.

7. The method for preparing polycyclic olefin materials according to claim 1, characterized in that, The melt blending temperature is 210℃~260℃, and the injection molding melt temperature is 270℃~280℃.

8. A polycyclic olefin material, characterized in that, It is prepared by any one of claims 1 to 7.

9. A wafer cassette, characterized in that, Includes a housing, said housing comprising the polycyclic olefin material of claim 8.

10. The wafer cassette according to claim 9, characterized in that, The wafer cassette is a front-opening wafer transport cassette or a photomask transport cassette.

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