A space-grade parylene-c based film and method of making the same

Abstract

The application provides an aerospace-grade Parylene-C-based film and a preparation method thereof, and belongs to the technical field of aerospace materials. The aerospace-grade Parylene-C-based film comprises a coupling agent layer, a Parylene-C main film layer, an adhesive layer and a polyimide protective film layer which are sequentially formed on a device to be plated. By using the coupling agent, the Parylene-C can be more firmly deposited on the surface of the device to be plated; by using the adhesive, the polyimide can be firmly bonded on the surface of the Parylene-C film; by optimizing the Parylene-C deposition process parameters, the thickness of the Parylene-C main film layer is accurately controlled; by optimizing the polyimide deposition process parameters, the thickness of the polyimide protective film layer is accurately controlled; by coating the Parylene-C main film layer with the polyimide protective film layer, the anti-radiation performance of the Parylene-C-based film is greatly improved. The aerospace-grade Parylene-C-based film material prepared by the application solves the problems of the existing Parylene series film, such as large thickness error, poor adhesion and weak anti-radiation capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material preparation, and particularly relates to a space-grade Parylene-C-based film and a preparation method thereof. BACKGROUND

[0002] The power brush is the main component of the electric power transmission of the spacecraft charging and discharging mechanism, and together with the cable, the electrical connector and the like, forms a complete power transmission channel in the single machine product. In order to ensure that the power brush can work stably, a three-proofing protective coating is usually sprayed on the surface of the power brush to provide complete insulation protection, so as to prevent intermittent corona discharge phenomenon that may occur under high voltage during power transmission, ensure reliable transmission of electric power, and thereby prolong the service life.

[0003] At present, the commonly used protective coating in the power brush is mainly p-xylene dimer (Parylene), which has the advantages of stable chemical properties, good transparency and excellent electrical insulation, and has a very broad application prospect in the fields of aerospace, electronic products and MEMS. However, as the spacecraft has higher and higher requirements for long service life and high reliability, the space environment faced by the spacecraft is becoming more and more complex, and the traditional Parylene film layer will fall off in a large area after long-term high and low temperature impact, and will be severely blistered and cracked after high-dose space irradiation, which cannot meet the current requirements of the power brush for good film adhesion, high and low temperature resistance and strong space irradiation resistance. For long-life spacecraft, the above risks will directly threaten the normal operation of various charging and discharging devices of the spacecraft, and eventually cause major safety hazards to the spacecraft. SUMMARY

[0004] In order to overcome the deficiencies in the prior art, the present application provides a space-grade Parylene-C-based film and a preparation method thereof, which solves the problem of poor high and low temperature impact and space irradiation resistance of the traditional Parylene film layer. The space-grade Parylene-C-based film has the characteristics of high thickness precision, good adhesion, high and low temperature resistance and strong space irradiation resistance, avoids the problems of film blistering, cracking and falling off in extreme space environment, greatly reduces the risk of failure of the spacecraft power brush, and ensures the long-term normal operation of the charging and discharging device of the spacecraft in orbit.

[0005] The technical scheme provided by the present application is as follows:

[0006] In a first aspect, a space-grade Parylene-C-based film includes a coupling agent layer, a Parylene-C main film layer, an adhesive layer and a polyimide protective film layer successively formed on a device to be plated. The Parylene-C main film layer has a thickness of 10-30 μm, and the polyimide protective film layer has a thickness of 2-5 μm.

[0007] Further, the coupling agent layer has a thickness of 20-150 nm and is prepared by using a silane coupling agent; and the adhesive layer has a thickness of 1-2 μm and is prepared by using an organic silicon resin adhesive or a silicone rubber adhesive.

[0008] In a second aspect, a method for preparing a space-grade Parylene-C-based film includes the following steps:

[0009] Hanging the cleaned devices to be plated in a deposition chamber of a vacuum vapor deposition device;

[0010] Placing a coupling agent into a coupling agent evaporation device of the vacuum vapor deposition device and placing Parylene-C powder into a sample tank in an evaporation chamber of the vacuum vapor deposition device;

[0011] Starting the coupling agent evaporation device to coat the coupling agent on the devices to be plated to prepare a coupling agent layer;

[0012] After the evaporation of the coupling agent is completed, evaporating the Parylene-C powder to prepare a Parylene-C main film layer;

[0013] After the evaporation of the Parylene-C powder is completed, taking out the devices to be plated, brushing an adhesive on the Parylene-C main film layer to prepare an adhesive layer, and immediately hanging the devices to be plated in the deposition chamber again after the brushing is completed;

[0014] Placing the weighed polyimide monomer into the cleaned sample tank, evaporating the polyimide monomer, and performing an imidization reaction after the evaporation of the polyimide monomer is completed to prepare a polyimide protective film layer, thereby completing the preparation of the space-grade Parylene-C-based film.

[0015] Further, in the step of hanging the cleaned devices to be plated in the deposition chamber of the vacuum vapor deposition device, there are also glass slides hung in the deposition chamber of the vacuum vapor deposition device, preferably, 1-2 glass slides should be hung in the area where the devices to be plated are hung, and the space between all the devices to be plated, between all the glass slides, and between the devices to be plated and the glass slides should be greater than one device-to-be-plated space; and / or

[0016] Protecting the areas of all the devices to be plated without a film.

[0017] Further, in the step of starting the coupling agent evaporation device to coat the coupling agent on the devices to be plated, the temperature of the coupling agent evaporation device is 160-180 °C, the evaporation time is 5-10 min, and the thickness of the coupling agent layer is 20-150 nm.

[0018] Furthermore, in the step of implementing Parylene-C powder evaporation, the evaporation temperature is 190–210°C, the pyrolysis furnace temperature is 680–700°C, the cold trap temperature is -50–-80°C, the chamber temperature is 20–30°C, and the chamber pressure is 1×10⁻⁶. -2 ~4×10 -2 Pa.

[0019] Furthermore, in the step of implementing Parylene-C powder evaporation, after the Parylene-C powder has evaporated by more than half, the glass slide is removed, and the film on the glass slide is removed for thickness monitoring; the mass of the remaining Parylene-C powder is weighed, and the evaporation process is adjusted according to the film thickness, the mass of the evaporated Parylene-C powder, and the target film thickness.

[0020] Furthermore, in the step of performing polyimide monomer evaporation, the evaporation temperature is 110–150°C, the chamber temperature is 30–50°C, and the chamber pressure is 10. -4 ~10 -3 Pa.

[0021] Furthermore, in the step of imidization reaction after the polyimide monomer has evaporated, the imidization reaction temperature is 250-350°C and the holding time is 1-2 hours.

[0022] The present invention provides an aerospace-grade Parylene-C-based thin film and its preparation method, which has the following characteristics:

[0023] Beneficial effects:

[0024] (1) The Parylene-C based film of the present invention enhances the interfacial bonding performance between the device to be coated and the Parylene-based film through the action of a specific coupling agent, improves the adhesion of the Parylene-C based film, and ensures that the film layer does not peel or fall off after hundreds of high and low temperature cycles, thus meeting the requirements of spacecraft on-orbit operation.

[0025] (2) The outermost layer of the Parylene-C based film of the present invention is a polyimide protective film layer. The polyimide film has strong resistance to space radiation and can greatly improve the tolerance of Parylene-C based film to space electrons, protons, ultraviolet and other space particles, thus meeting the requirements of long life of spacecraft.

[0026] (3) The present invention uses high coating evaporation rate powder as raw material and adopts vacuum vapor deposition process to prepare Parylene-C based thin film, which can more accurately control the overall thickness of the film and the thickness accuracy of the obtained Parylene-C based thin film is ≤5%. Attached Figure Description

[0027] Figure 1 Figure 1 is a schematic diagram of the aerospace grade Parylene-C based film of the present invention;

[0028] Figure 2 Figure 2 is a photograph of the aerospace grade Parylene-C based film (copper sheet) of the present invention;

[0029] Figure 3 Figure 3 is a photograph of the aerospace grade Parylene-C based film (copper sheet) of the present invention after adhesion testing;

[0030] Figure 4 Figure 4 is a photograph of the aerospace grade Parylene-C based film (copper sheet) of the present invention after 200 thermal cycles (-60°C to 140°C);

[0031] Figure 5 Figure 5 is a photograph of the aerospace grade Parylene-C based film (copper sheet) of the present invention after 1 x 10 15 e / cm 2 protons after electron irradiation;

[0032] Figure 6 Figure 6 is a photograph of the aerospace grade Parylene-C based film (copper sheet) of the present invention after 3 x 10 15 p / cm 2 protons after electron irradiation;

[0033] Figure 7 Figure 7 is a thermal decomposition curve of the aerospace grade Parylene-C based film of the present invention;

[0034] Figure 8 Figure 8 is a photograph of the Parylene-C based film (copper sheet) of the comparative example of the present invention after 200 thermal cycles (-60°C to 140°C). DETAILED DESCRIPTION

[0035] The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings.

[0036] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Although the drawings represent various aspects of implementations, the drawings are not necessarily drawn to scale and the drawings can be used to illustrate various aspects of implementations.

[0037] The application provides a space-grade Parylene-C-based film, which comprises a coupling agent layer, a Parylene-C main film layer, an adhesive layer and a polyimide protective film layer which are sequentially formed on a device to be plated, the thickness of the coupling agent layer is 20-150 nm, the thickness of the Parylene-C main film layer is 10-30 microns, the thickness of the adhesive layer is 1-2 microns, and the thickness of the polyimide protective film layer is 2-5 microns.

[0038] The coupling agent layer is prepared from a silane coupling agent, including but not limited to KH550, KH560, KH570, A-150 or A-151, etc.

[0039] The adhesive layer is prepared from a silicone resin adhesive and a silicone rubber adhesive, the silicone resin adhesive includes but is not limited to SH9501, H2081, H2082, etc., and the silicone rubber adhesive includes but is not limited to GD414, K704, etc.

[0040] The device surface is modified by plating the coupling agent layer on the device to be plated, and then the Parylene-C main film layer is bonded, so that the adhesion of the Parylene-C main film layer to the device to be plated and the high and low temperature impact resistance are improved; the adhesive layer is coated between the Parylene-C main film layer and the polyimide protective film layer, so that the adhesion between the polyimide protective film layer and the main film layer is improved; and the outermost layer is the polyimide protective film layer, so that the space radiation resistance of the film layer is improved.

[0041] In the application, the thickness precision of the Parylene-C-based film is less than or equal to 5%, the volume resistivity is (5*10 14 ~5*10 15 ) ohm*cm, the breakdown strength is greater than or equal to 150 kV / mm, the thermal decomposition temperature is greater than or equal to 400 DEG C, the adhesion is not less than level 1, the high and low temperature cycle resistance is not less than 100 times, the space electron radiation dose resistance is not less than 1*10 15 e / cm 2 , and the space proton radiation dose resistance is not less than 3*10 15 p / cm 2 .

[0042] The application further provides a preparation method of the space-grade Parylene-C-based film.

[0043] (I) pretreatment of the device to be plated

[0044] (1) the device to be plated and a glass slide are cleaned, inspected and baked for standby.

[0045] The device shell to be plated or the area to be plated in this step is an inorganic material, such as copper, beryllium bronze, gold, aluminum, and magnesium, or other inorganic materials such as silicon carbide SiC, aluminum nitride AlN, silicon nitride Si3N4, silicon dioxide SiO2, and silicate inorganic non-metallic materials.

[0046] The slide material includes silicon carbide SiC, aluminum nitride AlN, silicon nitride Si3N4, silicon dioxide SiO2, and silicate inorganic non-metallic materials.

[0047] The cleaning method is chemical solvent cleaning or ultrasonic cleaning, the cleaning time is 5-8 min, the baking temperature is 60-80°C, and the baking time is 1-2 h.

[0048] (II) Equipment preparation and determination of raw material quantity

[0049] (2) Clean the deposition chamber cavity of the vacuum vapor deposition equipment, ensure that there is no dust and other impurities in the deposition chamber, and then hang the cleaned device to be plated and the slide in the deposition chamber of the vacuum vapor deposition equipment, close the deposition chamber cavity, and ensure that it is sealed well.

[0050] In this step, all areas where the device to be plated is suspended should ensure that there are 1-2 slides, all devices to be plated, all slides, and all devices to be plated and slides should maintain a space greater than one device to be plated; all areas of the device to be plated that do not need to be coated with a film should be protected, and the protection materials include silicone rubber tape or epoxy resin tape, etc.

[0051] All slides should be uniformly coated with a weak alkaline release agent such as C200 release agent, and the intermediate part quality inspection is performed by measuring the thickness of the film taken from the slide during Parylene-C main film layer plating.

[0052] (3) According to the target thickness of the Parylene-C main film layer and the polyimide protective film layer, the number of film layers (the number of devices to be plated + the number of slides), and the plating film evaporation rate, the amount of Parylene-C powder and polyimide film monomer is determined.

[0053] In this step, the purity of Parylene-C powder is ≥99.5%, the plating film evaporation rate is ≥99.0%, and the melting point is >160°C.

[0054] In the step, the polyimide film monomer is p-phenyleneterephthalamic acid and 4,4'-diaminodiphenyl ether, the purity of p-phenyleneterephthalamic acid is greater than or equal to 99.0%, the evaporation rate of film plating is greater than or equal to 99.0%; the purity of 4,4'-diaminodiphenyl ether is greater than or equal to 99.0%, and the evaporation rate of film plating is greater than or equal to 99.0%. The evaporation rate of film plating is an important parameter affecting the thickness of the Parylene-C main film layer and the polyimide protective film layer, and the feeding amount of Parylene-C powder, p-phenyleneterephthalamic acid and 4,4'-diaminodiphenyl ether needs to be determined according to the target thickness of each film layer and the corresponding evaporation rate of film plating, and the size of the evaporation rate of film plating directly affects the thickness accuracy of the Parylene-C main film layer, and the higher the evaporation rate of film plating, the easier the thickness of the obtained film layer is controlled.

[0055] (Three), film layer preparation

[0056] (4), the required amount of Parylene-C powder and polyimide film monomer is weighed, and the Parylene-C powder is placed in the sample tank in the evaporation chamber; the corresponding coupling agent is weighed according to the amount of Parylene-C, and is placed in the coupling agent evaporation device.

[0057] In the step, the sample tank containing Parylene-C powder is paved with an aluminum foil or other mat layer which does not affect the film plating, and the mass of the mat layer is known, so that the amount of Parylene-C powder in the intermediate stage can be calculated and the Parylene-C powder can be cleaned subsequently.

[0058] In the step, the addition ratio of the polyimide film monomers p-phenyleneterephthalamic acid and 4,4'-diaminodiphenyl ether is between 1 and 1.3.

[0059] In the step, the amount of the coupling agent is 0.5-1 mL.

[0060] The inventors have determined that the coupling agent layer is a silane coupling agent, and the thickness of the coupling agent layer is 20-150 nm. If the thickness of the coupling agent layer is greater than the maximum value in the above range, the adhesion between the coupling agent layer and the substrate layer is poor due to incomplete release of internal stress, and if the thickness of the coupling agent layer is less than the minimum value in the above range, the coupling agent cannot completely cover the substrate material and the Parylene-C main film layer due to unstable brushing process.

[0061] The type of coupling agent is an important parameter affecting the adhesion grade of the Parylene-C main film layer. The better the interface bonding between the coupling agent and the Parylene-C main film layer and the device to be plated, the stronger the adhesion performance of the Parylene-C-based film obtained, and the higher the adhesion grade. The silane coupling agent has stronger adhesion performance on metal and inorganic materials than Parylene-C. In addition, it can copolymerize with the Parylene-C-based film under the action of high temperature, thereby enhancing the bonding between the Parylene-C main film layer and the substrate material.

[0062] (5) Start the coupling agent evaporation device to coat the coupling agent on the device to be plated. The temperature of the coupling agent evaporation device is 160-180°C, and the evaporation time is 5-10 min, so that the thickness of the coupling agent layer is 20-150 nm.

[0063] The use of a specific coupling agent enhances the interface bonding performance between the device to be plated and the Parylene-C main film layer, improves the adhesion of the Parylene-C main film layer, and ensures that the film layer does not peel off after hundreds of high-low temperature cycles, meeting the requirements of spacecraft in-orbit operation. The formation of the coupling agent layer has high requirements on the plating process. The temperature of the evaporation device affects the uniformity and stability of the plated layer. If the temperature is higher than the maximum value of the above range, the film layer is formed too quickly, local protrusions are easily formed on the surface of the film layer, which is not conducive to the formation of the upper film layer, and the overall bonding force between the device to be plated and the Parylene-C main film layer is reduced. If the temperature is lower than the minimum value of the above range, the coupling agent cannot evaporate completely in time, resulting in incomplete adhesion of the coupling agent on the substrate material within the set time, and the optimal bonding effect between the substrate material and the Parylene-C main film layer cannot be achieved.

[0064] (6) After the evaporation of the coupling agent is completed, the Parylene-C powder is evaporated. The evaporation temperature is 190-210°C, the cracking furnace temperature is 680-700°C, the cold trap temperature is -50 to -80°C, the chamber temperature is 20-30°C, and the chamber pressure is 1x10 -2 ~4x10 -2 Pa. The above evaporation temperature range can ensure that the Parylene-C powder completely changes from a powder state to a gas state within a specified time without destroying its structure; and the above cracking furnace temperature range can ensure that the Parylene-C gas undergoes a polymerization reaction within a set time and forms in the cold trap chamber.

[0065] (7) After half of the Parylene-C powder is evaporated, the glass slide is taken out, the film on the glass slide is removed, and the thickness is monitored; the mass of the remaining Parylene-C powder is weighed, and whether to adjust the evaporation process is selected according to the film thickness, the mass of the evaporated Parylene-C powder, and the target film thickness.

[0066] If the film thickness is lower than the theoretical film thickness range corresponding to the mass of the evaporated Parylene-C powder, the evaporation temperature and the cracking furnace temperature are reduced; if the film thickness is higher than the theoretical film thickness range corresponding to the mass of the evaporated Parylene-C powder, the evaporation temperature and the cracking furnace temperature are increased.

[0067] The Parylene-C main film layer has a thickness of 10-30 μm, which can achieve good adhesion and anti-electric breakdown performance under the premise of ensuring the lightness of the film layer.

[0068] (8) After the Parylene-C powder is evaporated, the device to be plated and the glass slide are taken out, an adhesive is brushed on the Parylene-C main film layer, and the device to be plated is immediately hung in the deposition chamber again after brushing. The adhesive brushing range needs to cover the surface of the Parylene-C main film layer and all the sides.

[0069] (9) The residual Parylene-C powder in the sample tank is cleaned, a new pad is replaced, the weighed polyimide monomer is put into the sample tank, and polyimide monomer evaporation is performed, with an evaporation temperature of 110-150 °C, a chamber temperature of 30-50 °C, a chamber pressure of 10 -4 ~10 -3 Pa;

[0070] (10) After the polyimide monomer is evaporated, an imidization reaction is performed, with a chamber temperature (imidization reaction temperature) of 250-350 °C and a holding time of 1-2 h.

[0071] Examples

[0072] Example 1

[0073] The following one kind of aerospace-grade Parylene-C-based film preparation method is adopted to prepare three batches of aerospace-grade Parylene-C-based films, and the specific steps are as follows:

[0074] (1) Take 40 cm x 40 cm copper sheet and 40 cm x 40 cm glass slide, clean with acetone, then ultrasonic clean for 5 min, and after no visible contaminants, bake in an 80 °C oven for 1 h;

[0075] (2) After cleaning the deposition chamber of the vacuum vapor deposition equipment to ensure that there is no dust or other impurities in the deposition chamber, 20 pieces of clean 40cm x 40cm copper sheet and 5 pieces of 40cm x 40cm glass slides are hung in the equipment, the glass slides are evenly coated with weak alkaline release agent C200 release agent, the deposition chamber is closed to ensure that it is sealed well; all the areas where the copper sheets are hung should ensure that there is 1-2 glass slides, and the space between all the copper sheets, all the glass slides and all the copper sheets and glass slides should be kept greater than one copper sheet space; the side of all the copper sheets without film coating is protected with silicone rubber tape;

[0076] (3) The target thickness of the film is determined to be 27μm for the Parylene-C main film layer and 3μm for the polyimide protective film layer;

[0077] (4) 100 grams of Parylene-C powder is weighed and placed in an aluminum foil of known mass, and then both are placed in the evaporation chamber sample tank; 0.5mL of KH550 coupling agent is added to the coupling agent evaporation device;

[0078] (5) The coupling agent evaporation device is started to coat the coupling agent on the substrate, and the temperature of the coupling agent evaporation device is 160℃, and the evaporation time is 10 minutes;

[0079] (6) After the evaporation of the coupling agent is completed, two glass slides are taken out for five-point thickness monitoring and recording (between 20-150nm); continue to evaporate the Parylene-C powder, with an evaporation temperature of 200℃, a cracking furnace temperature of 680℃, a cold trap temperature of -60℃, a chamber temperature of 27℃, and a chamber pressure of 2.5x10 -2 Pa.

[0080] (7) After about 50 grams of Parylene-C powder is evaporated, two glass slides are taken out, the film on the glass slides is removed for thickness monitoring and recording (average thickness about 14.3μm); the mass of the remaining Parylene-C powder in the aluminum foil is weighed and recorded (about 50g), and it is determined that the Parylene-C powder evaporation process will not be adjusted.

[0081] (8) After the recording is completed, the Parylene-C powder is placed again in the evaporation chamber for continuous evaporation, and after the evaporation is completed, all the copper sheets and glass slides are taken out, two glass slides are taken out, the film on the glass slides is removed for five-point thickness monitoring and recording, and the average thickness of the Parylene-C main film layer is obtained (three batches of data are 26μm, 26.1μm, and 25.5μm respectively); after 10 minutes, GD414 adhesive (1-2μm) is brushed on the Parylene-C base film, and immediately after the brushing is completed, the sample and the remaining glass slides are hung again in the deposition chamber;

[0082] (9)Clean the residual Parylene-C powder in the sample tank, replace the new aluminum foil, and put 2.5 g of pyromellitic dianhydride and 4,4'-oxydianiline into the sample tank for polyimide monomer evaporation. The evaporation temperature is 120℃, the chamber temperature is 35℃, and the chamber pressure is 5x10 -4 Pa;

[0083] (10)After the polyimide monomer evaporation is completed, the imidization reaction is carried out at a chamber temperature of 280℃ for 1.5h.

[0084] (12)After the temperature returns to room temperature, remove all the copper sheets and glass slides, remove the films on the two slides, and perform five-point thickness monitoring and record the results. The average total thickness of the Parylene-C-based film, the average thickness of the polyimide protective film layer (three batches of data are 2.6μm, 3.0μm, and 3.5μm respectively), and the average thickness of the Parylene-C main film layer are obtained. The average thickness of the polyimide protective film layer is equal to the average total thickness of the Parylene-C-based film minus the average thickness of the Parylene-C main film layer, and the thicknesses of the coupling agent layer and the adhesive layer are ignored.

[0085] To verify the reliability of the aerospace-grade Parylene-C-based film, the thickness accuracy, volume resistivity, breakdown strength, thermal decomposition temperature, and adhesion of the film were tested, and the film was subjected to 200 times of high-low temperature cycling (-60℃-140℃), 1x10 15 e / cm 2 space electron irradiation test, and 3x10 15 p / cm 2 space proton irradiation test. The thickness test results are shown in Table 1, the volume resistivity and breakdown strength test results are shown in Table 2, the adhesion test results are shown in Table 3 and Figure 3 A, the appearance of the film after temperature cycling is shown in Figure 4 A, the appearance after electron irradiation is shown in Figure 5 A, the appearance after proton irradiation is shown in Figure 6 A, and the thermal decomposition curve is shown in Figure 7 .

[0086] Table 1 Thickness test results of aerospace-grade Parylene-C-based film

[0087]

[0088] Table 2 Electrical performance test results of aerospace-grade Parylene-C-based film

[0089]

[0090] Table 3 Adhesion grade test results of aerospace-grade Parylene-C-based film

[0091]

[0092] Experiments show that the space-grade Parylene-C-based film prepared by the application has small thickness deviation, good bonding performance with a metal base, high thermal stability, good insulation performance, strong temperature impact resistance and space radiation resistance, and solves the problems of blistering and cracking of traditional Parylene films in space application.

[0093] The space-grade Parylene-C-based film prepared by the application improves the adhesion performance and space environment adaptability of the film under the premise of ensuring the thickness precision, insulation performance and thermal stability performance of the film to meet the application.

[0094] Example 2

[0095] The following one of the preparation methods of the space-grade Parylene-C-based film is used to prepare three batches of space-grade Parylene-C-based films, and the specific steps are as follows:

[0096] (1) Take 40cm*40cm gold-plated sheets and 40cm*40cm glass slides, clean them with acetone, then ultrasonic clean for 5min, and then bake them in an 80℃ oven for 1h after no visible contaminants are found;

[0097] (2) Clean the deposition chamber cavity of the vacuum vapor deposition equipment, ensure that there is no dust and other impurities in the deposition chamber, then hang 20 pieces of clean 40cm*40cm gold-plated materials and 5 pieces of 40cm*40cm glass slides in the equipment, evenly coat weak alkaline release agent C200 release agent on the glass slides, close the deposition chamber to ensure that it is sealed well; all the areas where the gold-plated sheets are hung should ensure that there is 1-2 glass slides, and the space between all the gold-plated sheets, all the glass slides and all the gold-plated sheets and glass slides should be greater than one gold-plated sheet space; the side of all the gold-plated sheets without coating film is protected by silicone rubber tape;

[0098] (3) Determine that the target thickness of the film is 17μm for the Parylene-C main film layer and 3μm for the polyimide protective film layer;

[0099] (4) Weigh 70g of Parylene-C powder and put it into an aluminum foil with a known mass, then put them together into the evaporation chamber sample tank; add 0.5mL of KH550 coupling agent into the coupling agent evaporation device;

[0100] (5) Start the coupling agent evaporation device to coat the coupling agent on the substrate, the coupling agent evaporation device temperature is 170℃, the evaporation time is 7 minutes;

[0101] (6) After the completion of the coupling agent evaporation, take out two glass slides to monitor the five-point thickness and record (between 20-150 nm); continue to evaporate the Parylene-C powder, the evaporation temperature is 205℃, the cracking furnace temperature is 690℃, the cold trap temperature is -60℃, the chamber temperature is 27℃, the chamber pressure is 3.0x10 -2 Pa.

[0102] (7) After the Parylene-C powder is evaporated about 34 grams, take out the glass slide, remove the film on the glass slide to monitor the thickness and record (the average thickness is about 8.8μm); weigh the remaining Parylene-C powder in the aluminum foil and record (about 36g), and determine not to adjust the Parylene-C powder evaporation process.

[0103] (8) After the record is completed, put the Parylene-C powder into the evaporation chamber again to continue evaporation, and after the complete evaporation, take out all the gold-plated sheets and glass slides, take two glass slides, remove the film on the glass slides to monitor the five-point thickness and record, and obtain the average thickness of the Parylene-C main film layer (three batches of data are 16.7μm, 16.4μm, and 17.8μm respectively); after 10 minutes, brush the GD414 adhesive (1-2μm) on the Parylene-C base film, and immediately hang the sample and the remaining glass slides into the deposition chamber again after the brushing is completed;

[0104] (9) Clean the remaining Parylene-C powder in the sample tank, replace the new aluminum foil, and each weigh 2.5g of pyromellitic dianhydride and 4,4'-oxydianiline into the sample tank to evaporate the polyimide monomer, the evaporation temperature is 120℃, the chamber temperature is 35℃, and the chamber pressure is 5x10 -4 Pa;

[0105] (10) After the polyimide monomer evaporation is completed, the imidization reaction is carried out, the chamber temperature is 280℃, and the holding time is 1.5h.

[0106] (12) Turn off the vapor deposition equipment, take out all the gold-plated sheets and glass slides after the temperature returns to room temperature, remove the film on two glass slides to monitor the five-point thickness and record, and obtain the average value of the total thickness of the Parylene-C base film and the average thickness of the polyimide protective film layer (three batches of data are 2.6μm, 2.8μm, and 2.8μm respectively), wherein the average thickness of the polyimide protective film layer = the average value of the total thickness of the Parylene-C base film - the average thickness of the Parylene-C main film layer, and the thicknesses of the coupling agent layer and the adhesive layer are ignored.

[0107] To verify the reliability of the aerospace-grade Parylene-C-based film of the present application, the thickness accuracy, volume resistivity, breakdown strength and adhesion of the film were tested, and 200 times of high-low temperature cycles (-60℃-140℃), 1×10 15 e / cm 2 space electron irradiation test and 3×10 15 p / cm 2 space proton irradiation test were carried out. The thickness test results are shown in Table 4, the volume resistivity and breakdown strength test results are shown in Table 5, the adhesion test results are shown in Table 6 and Figure 3 B, the appearance of the film after temperature cycle is shown in Figure 4 B, the appearance after electron irradiation is shown in Figure 5 B, and the appearance after proton irradiation is shown in Figure 6 B.

[0108] Table 4 Thickness test results of the aerospace-grade Parylene-C-based film

[0109]

[0110] Table 5 Electrical property test results of the aerospace-grade Parylene-C-based film

[0111]

[0112] Table 6 Adhesion grade test results of the aerospace-grade Parylene-C-based film

[0113]

[0114] Comparative Example 1

[0115] Three batches of aerospace-grade Parylene-C-based films were prepared by using one of the following preparation methods of aerospace-grade Parylene-C-based film, and the specific steps are as follows:

[0116] (1) Take 40cm×40cm copper sheet and 40cm×40cm glass slide, clean them with acetone and then ultrasonic cleaning for 5min, and then bake them in an 80℃ oven for 1h after no visible contaminants are found;

[0117] (2) After cleaning the deposition chamber of the vacuum vapor deposition equipment to ensure that there is no dust or other impurities in the deposition chamber, 20 pieces of clean 40 cm x 40 cm copper sheet and 5 pieces of 40 cm x 40 cm glass slides are hung in the equipment, the glass slides are evenly coated with weak alkaline release agent C200 release agent, the deposition chamber is closed to ensure that it is sealed well; all areas where the copper sheet is hung should ensure that there is 1-2 pieces of glass slide, and the space between all copper sheets, all glass slides and all copper sheets and glass slides should be kept greater than one copper sheet space; the side of all copper sheets without film coating is protected with silicone rubber tape;

[0118] (3) The target thickness of the film is determined to be 27 μm for the Parylene-C main film layer and 3 μm for the polyimide protective film layer;

[0119] (4) 100 grams of Parylene-C powder is weighed and placed in an aluminum foil of known mass, and then both are placed in the evaporation chamber sample tank; 0.5 mL of KH550 coupling agent is added to the coupling agent evaporation device;

[0120] (5) The coupling agent evaporation device is started to coat the coupling agent on the substrate, and the temperature of the coupling agent evaporation device is 200°C, and the evaporation time is 5 minutes;

[0121] (6) After the evaporation of the coupling agent is completed, two glass slides are taken out for five-point thickness monitoring and recording (between 20-150 nm); continue to evaporate the Parylene-C powder, the evaporation temperature is 200°C, the cracking furnace temperature is 680°C, the cold trap temperature is -60°C, the chamber temperature is 27°C, and the chamber pressure is 2.5 x 10 -2 Pa.

[0122] (7) After about 50 grams of Parylene-C powder is evaporated, the glass slides are taken out, the film on the glass slides is removed for thickness monitoring and recording (average thickness is about 13.9 μm); the mass of the remaining Parylene-C powder in the aluminum foil is weighed and recorded (about 53 g), and it is determined that the Parylene-C powder evaporation process is not adjusted.

[0123] (8) After the recording is completed, the Parylene-C powder is placed again in the evaporation chamber for continuous evaporation, and after the evaporation is completed, all copper sheets and glass slides are taken out, two glass slides are taken out, the film on the glass slides is removed for five-point thickness monitoring and recording, and the average thickness of the Parylene-C main film layer is obtained (three batches of data are 25.9 μm, 28.6 μm, and 28.6 μm, respectively); after 10 minutes, GD414 adhesive (1-2 μm) is brushed on the Parylene-C base film, and immediately after the brushing is completed, the sample and the remaining glass slides are hung again in the deposition chamber;

[0124] (9) Clean up the residual Parylene-C powder in the sample tank, replace the new aluminum foil, and each take 2.5 g of pyromellitic dianhydride and 4,4'-oxydianiline into the sample tank for polyimide monomer evaporation. The evaporation temperature is 120℃, the chamber temperature is 35℃, and the chamber pressure is 5x10 -4 Pa;

[0125] (10) After the polyimide monomer evaporation is completed, the imidization reaction is carried out, the chamber temperature is 280℃, and the holding time is 1.5h.

[0126] (12) Turn off the vapor deposition equipment, take out all the copper sheets and glass slides after the temperature returns to room temperature, remove the films on the two slides for five-point thickness monitoring and record, obtain the average total thickness of the Parylene-C based film, the average thickness of the polyimide protective film layer (three batches of data are 2.9μm, 2.7μm, and 3.0μm respectively), wherein the average thickness of the polyimide protective film layer = the average total thickness of the Parylene-C based film - the average thickness of the Parylene-C main film layer, and the thicknesses of the coupling agent layer and the adhesive layer are ignored.

[0127] To verify the reliability of the aerospace-grade Parylene-C based film, the thickness accuracy and adhesion of the film are tested, and 200 times of high-low temperature cycles (-60℃-140℃) are carried out. The thickness test results are shown in Table 7, the adhesion test results are shown in Table 8, and the appearance after temperature impact is shown in Figure 8 Due to the deviation of the coupling agent evaporation device temperature from the required range of the application, the overall adhesion of the plated device and the Parylene-C main film layer is reduced, and finally the overall adhesion of the aerospace-grade Parylene-C based film is reduced.

[0128] Table 7 Thickness test results of aerospace-grade Parylene-C based film

[0129]

[0130] Table 8 Test results of adhesion grade of aerospace-grade Parylene-C based film

[0131]

[0132] The application is described in detail above in combination with specific embodiments and exemplary examples, but these descriptions cannot be understood as limitations of the application. Those skilled in the art understand that various equivalent substitutions, modifications or improvements can be made to the technical solutions and embodiments of the application without deviating from the spirit and scope of the application, and these all fall within the scope of the application. The protection scope of the application is subject to the appended claims.

[0133] Those aspects of the application which are not specifically described in the specification are well known to those skilled in the art.

Claims

1. A space qualified Parylene-C based film, characterized in that, The coupling agent layer is prepared by using silane coupling agent.

2. The space qualified Parylene-C based film of claim 1, wherein, The thickness of the coupling agent layer is 20-150 nm.

3. The space qualified Parylene-C based film of claim 1, wherein, The thickness of the adhesive layer is 1-2 microns.

4. A method of producing a space qualified Parylene-C based film as claimed in any one of claims 1 to 3, characterised in that, The method comprises the following steps: The cleaned plating devices are hung in the deposition chamber of the vacuum vapor deposition equipment; The coupling agent is put into the coupling agent evaporation device of the vacuum vapor deposition equipment, and the Parylene-C powder is put into the sample tank in the evaporation chamber of the vacuum vapor deposition equipment; The coupling agent evaporation device is started to coat the coupling agent on the plating devices to prepare the coupling agent layer; After the evaporation of the coupling agent is completed, the Parylene-C powder is evaporated to prepare the Parylene-C main film layer; After the evaporation of the Parylene-C powder is completed, the plating devices are taken out, the adhesive is brushed on the Parylene-C main film layer to prepare the adhesive layer, and the plating devices are hung in the deposition chamber again immediately after the brushing is completed; The weighed polyimide monomer is put into the cleaned sample tank, and the polyimide monomer is evaporated; after the evaporation of the polyimide monomer is completed, the imidization reaction is carried out to prepare the polyimide protective film layer, and the preparation of the aerospace-grade Parylene-C-based film is completed.

5. The method of claim 4, wherein the Parylene-C based film is a space qualified film. In the step of hanging the cleaned plating devices in the deposition chamber of the vacuum vapor deposition equipment, there are also glass slides hung in the deposition chamber of the vacuum vapor deposition equipment, and 1-2 glass slides should be ensured in the area where the plating devices are hung, and the space between all the plating devices, between all the glass slides, and between the plating devices and the glass slides should be greater than one plating device space. The areas of all the plating devices without thin film coating are protected.

6. The method of claim 4, wherein the Parylene-C based film is a space qualified film. In the step of starting the coupling agent evaporation device to coat the coupling agent on the plating devices, the temperature of the coupling agent evaporation device is 160-180 DEG C, and the evaporation time is 5-10 min, so that the thickness of the coupling agent layer is 20-150 nm.

7. The method of claim 4, wherein the Parylene-C based film is a space qualified film. In the step of evaporating Parylene-C powder, the evaporation temperature is 190-210℃, the cracking furnace temperature is 680-700℃, the cold trap temperature is -50--80℃, the chamber temperature is 20-30℃, and the chamber pressure is 1x10 -2 -4x10 -2 Pa.

8. The method of claim 5, wherein the Parylene-C based film is a space qualified film. In the step of evaporating the Parylene-C powder, the glass slides are taken out after more than half of the Parylene-C powder is evaporated, the thin film on the glass slides is removed for thickness monitoring; the mass of the remaining Parylene-C powder is weighed, and whether the evaporation process is adjusted is selected according to the film thickness, the mass of the evaporated Parylene-C powder, and the target film thickness.

9. The method of claim 4, wherein the Parylene-C based film is a space qualified film. The evaporation temperature in the step of evaporating the polyimide monomer is 110-150°C, the chamber temperature is 30-50°C, and the chamber pressure is 10 -4 -10 -3 Pa.

10. The method of claim 4, wherein the space between the first and second substrates is less than 1 mm. In the step of carrying out the imidization reaction after the evaporation of the polyimide monomer is completed, the imidization reaction temperature is 250-350 DEG C, and the holding time is 1-2 h.

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