Method for preparing hard film on surface of boron nitride evaporation boat

Abstract

The invention relates to the technical field of evaporation boat coating, and particularly discloses a method for preparing a hard film on the surface of a boron nitride evaporation boat, a DLC coating is deposited on the surface of the evaporation boat, the problems of aluminum splashing and the like occurring after the evaporation boat is heated in the coating process are effectively solved, and the product quality is improved. The wear resistance, chemical stability, corrosion resistance and the like of the evaporation boat are improved, and the service life of the evaporation boat is prolonged, so that the production efficiency of vacuum aluminum plating enterprises is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of evaporation boat coating, in particular to a method for preparing a hard film on the surface of a boron nitride evaporation boat. Background Art

[0002] Vacuum evaporation technology is the most typical PVD vapor deposition technology. Vacuum evaporation aluminum plating is a method of melting and evaporating aluminum at high temperature under vacuum conditions, so that aluminum atoms are deposited on the surface of the plated material to form an aluminum film. It is widely used in packaging materials, capacitors, cathode ray tubes and other fields. The evaporation boat that holds the aluminum source is the most important consumable part in vacuum aluminum plating. The evaporation effect and life of the evaporation boat determine the quality of aluminum plating and affect the production efficiency and cost of the enterprise.

[0003] Regarding the use of the evaporation boat, during the coating process, after the evaporation boat is heated, the aluminum liquid cannot spread quickly, that is, the molten pool of the evaporation boat is very small, which will cause aluminum accumulation. The accumulated aluminum liquid will boil, causing aluminum liquid to splash and produce aluminum splashing, splashing holes, and even film burn-through and film breakage. The boron nitride evaporation boat we are currently using is a three-component composition (boron nitride, titanium diboride, aluminum nitride). After normal film formation, there will be deposited impurities on the surface of the evaporation boat. The aluminum liquid in the evaporation boat will react chemically with the components of the evaporation boat, and fine (three-component) particles will collapse, and produce larger aluminum splash points and concave and convex points on the film surface with the aluminum liquid. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a hard film on the surface of a boron nitride evaporation boat, so as to solve the problem of aluminum splashing after the evaporation boat is heated during the coating process and improve product quality.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0007] After the evaporation boat is pretreated, a mixed gas of butane, nitrogen and argon is introduced under vacuum, and a DLC coating is deposited on the evaporation boat substrate using plasma deposition technology, and then cooled to obtain a coated evaporation boat.

[0008] As a limitation of the present invention, the method for pretreatment of the evaporation boat is:

[0009] First use ultrasonic cleaning to remove dust and impurities on the surface of the evaporation boat, and then perform plasma cleaning.

[0010] As a limitation of the present invention, the plasma cleaning parameters are: argon gas is filled for 1 to 2 minutes before the RF power is turned on, the argon gas flow rate is 55 to 65 sccm, the RF power is 790 to 810 W, and the cleaning time is 3 to 10 minutes.

[0011] As a limitation of the present invention, before depositing the DLC coating, a mixture of butane, nitrogen and argon is first filled for 1 to 2 minutes, with a butane flow rate of 93 to 97 sccm, an argon flow rate of 63 to 67 sccm, and a nitrogen flow rate of 13 to 17 sccm.

[0012] As a limitation of the present invention, when depositing the DLC coating, the distance between the evaporation boat and the anode is 20 cm to 25 cm.

[0013] As a limitation of the present invention, when depositing the DLC coating, the RF power is 1490-1510 W, the coating time is 220-260 min, and the pressure during coating is 1-1000 Pa greater than the external environment pressure.

[0014] As a limitation of the present invention, the DLC coating is cooled after deposition, and the cooling time is 30 minutes to 60 minutes.

[0015] As a limitation of the present invention, when the DLC coating is deposited by plasma technology, 1 to 50 evaporation boats can be processed simultaneously, and the interval between the evaporation boats is 10 mm to 15 mm.

[0016] A DLC coating evaporation boat, with a coating thickness of 0.05 mm to 0.1 mm, is manufactured by the above method.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] A DLC coating is deposited on the surface of the evaporation boat. The coating has good electrical conductivity, reduces the resistance value of the evaporation boat, enhances the electrical conductivity of the evaporation boat, heats up the boat surface faster, and makes the evaporation current fluctuation more stable; reduces the friction coefficient of the aluminum liquid, so that the aluminum liquid can move more smoothly and cover the entire boat surface during the coating process, thereby improving the evaporation efficiency; enhances the wear resistance of the evaporation boat surface, and compared with the uncoated boat, it can maintain a good surface state after multiple runs, avoiding rough surface pits caused by aluminum wire wear, aluminum splashing, splashing holes and other problems; enhances the chemical stability of the evaporation boat surface, prevents the evaporation boat surface from deteriorating or contaminating the coating material due to chemical reactions, and ensures the purity and quality of the coating; increases the corrosion resistance of the evaporation boat, avoids the corrosion of the evaporation boat by corrosive gases or substances that may exist during evaporation, and prevents water vapor stored in the outside atmosphere from invading the boat surface and interior, reduces the risk of corrosion of the evaporation boat, and ensures that it can still work normally in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1The diagrams of the two evaporation boats are compared. The oval marked part is the molten pool. The left side is a schematic diagram of the uncoated evaporation boat after use, and the right side is a schematic diagram of the coated evaporation boat after use. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1: A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0022] Step 1: Evaporation Boat Pretreatment

[0023] First, use ultrasonic cleaning to remove impurities, dust and other pollutants on the surface of the evaporation boat, and then use CVD equipment to use plasma to clean the surface of the evaporation boat to improve the adhesion and quality of the film. The plasma cleaning process parameters are: argon flow rate 60sccm, cleaning time 5min, RF power 800W, and argon is filled for 2min before turning on the RF power to allow the gas to fill the entire reaction chamber and maintain stable constant vacuum for cleaning.

[0024] Step 2: Evaporation boat coating

[0025] Place the evaporation boat at the bottom of the copper base of the reaction chamber (cathode), place the evaporation boat substrate in the reaction chamber and keep a distance of 20 cm between the evaporation boat substrate and the anode plate (retractable and movable) to evacuate. Before film formation begins, close the high vacuum valve (the low vacuum valve of the previous chamber is opened at this time) to keep the chemical vapor deposition chamber in a constant vacuum and positive pressure state. The carbon-containing gas butane, nitrogen, and argon are introduced into the reaction nozzle together and inflated for 2 minutes to fill the entire reaction chamber with the mixed gas, wherein the butane flow rate is 95sccm, the argon flow rate is 65sccm, and the nitrogen flow rate is 15sccm. After 2 minutes, turn on the RF power supply for coating, the RF power supply power is 1500W, the coating time is 240min, and the pressure during coating is greater than the external environment pressure of 1000Pa. Deposit the DLC coating on the evaporation boat substrate. After the deposition is completed, cool for 45 minutes to obtain the coated evaporation boat.

[0026] Example 2: A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0027] Step 1: Evaporation Boat Pretreatment

[0028] First, use ultrasonic cleaning to remove impurities, dust and other pollutants on the surface of the evaporation boat, and then use CVD equipment to use plasma to clean the surface of the evaporation boat to improve the adhesion and quality of the film. The plasma cleaning process parameters are: argon flow rate 60sccm, cleaning time 5min, RF power 800W, and argon is filled for 2min before turning on the RF power to allow the gas to fill the entire reaction chamber and maintain stable constant vacuum for cleaning.

[0029] Step 2: Evaporation boat coating

[0030] Place the evaporation boat at the bottom of the copper base of the reaction chamber (cathode), place the evaporation boat substrate in the reaction chamber and keep a distance of 21 cm between the evaporation boat substrate and the anode plate (retractable and movable) to evacuate. Before film formation begins, close the high vacuum valve (the low vacuum valve of the previous chamber is opened at this time) to keep the chemical vapor deposition chamber in a constant vacuum and positive pressure state. The carbon-containing gases butane, nitrogen, and argon are introduced into the reaction nozzle together and inflated for 2 minutes to fill the entire reaction chamber with the mixed gas, wherein the butane flow rate is 95sccm, the argon flow rate is 65sccm, and the nitrogen flow rate is 15sccm. After 2 minutes, turn on the RF power supply for coating, the RF power supply power is 1500W, the coating time is 240min, and the pressure during coating is greater than the external environment pressure of 1000Pa. Deposit the DLC coating on the evaporation boat substrate. After the deposition is completed, cool for 45 minutes to obtain the coated evaporation boat.

[0031] Example 3: A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0032] Step 1: Evaporation Boat Pretreatment

[0033] First, use ultrasonic cleaning to remove impurities, dust and other pollutants on the surface of the evaporation boat, and then use CVD equipment to use plasma to clean the surface of the evaporation boat to improve the adhesion and quality of the film. The plasma cleaning process parameters are: argon flow rate 60sccm, cleaning time 5min, RF power 800W, and argon is filled for 2min before turning on the RF power to allow the gas to fill the entire reaction chamber and maintain stable constant vacuum for cleaning.

[0034] Step 2: Evaporation boat coating

[0035] Place the evaporation boat at the bottom of the copper base of the reaction chamber (cathode), place the evaporation boat substrate in the reaction chamber and keep a distance of 22 cm between the evaporation boat substrate and the anode plate (retractable and movable) to evacuate. Before film formation begins, close the high vacuum valve (the low vacuum valve of the previous chamber is opened at this time) to keep the chemical vapor deposition chamber in a constant vacuum and positive pressure state. The carbon-containing gases butane, nitrogen, and argon are introduced into the reaction nozzle together and inflated for 2 minutes to fill the entire reaction chamber with the mixed gas, wherein the butane flow rate is 95sccm, the argon flow rate is 65sccm, and the nitrogen flow rate is 15sccm. After 2 minutes, turn on the RF power supply for coating, the RF power supply power is 1500W, the coating time is 240min, and the pressure during coating is greater than the external environment pressure of 1000Pa. Deposit the DLC coating on the evaporation boat substrate. After the deposition is completed, cool for 45 minutes to obtain the coated evaporation boat.

[0036] Example 4: A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0037] Step 1: Evaporation Boat Pretreatment

[0038] First, use ultrasonic cleaning to remove impurities, dust and other pollutants on the surface of the evaporation boat, and then use CVD equipment to use plasma to clean the surface of the evaporation boat to improve the adhesion and quality of the film. The plasma cleaning process parameters are: argon flow rate 60sccm, cleaning time 5min, RF power 800W, and argon is filled for 2min before turning on the RF power to allow the gas to fill the entire reaction chamber and maintain stable constant vacuum for cleaning.

[0039] Step 2: Evaporation boat coating

[0040] Place the evaporation boat at the bottom of the copper base of the reaction chamber (cathode), place the evaporation boat substrate in the reaction chamber and keep a distance of 23 cm between the evaporation boat substrate and the anode plate (retractable and movable) to evacuate. Before film formation begins, close the high vacuum valve (the low vacuum valve of the previous chamber is opened at this time) to keep the chemical vapor deposition chamber in a constant vacuum and positive pressure state. The carbon-containing gases butane, nitrogen, and argon are introduced into the reaction nozzle together and inflated for 2 minutes to fill the entire reaction chamber with the mixed gas, wherein the butane flow rate is 95sccm, the argon flow rate is 65sccm, and the nitrogen flow rate is 15sccm. After 2 minutes, turn on the RF power supply for coating, the RF power supply power is 1500W, the coating time is 240min, and the pressure during coating is greater than the external environment pressure of 1000Pa. Deposit the DLC coating on the evaporation boat substrate. After the deposition is completed, cool for 45 minutes to obtain the coated evaporation boat.

[0041] Example 5: A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0042] Step 1: Evaporation Boat Pretreatment

[0043] First, use ultrasonic cleaning to remove impurities, dust and other pollutants on the surface of the evaporation boat, and then use CVD equipment to use plasma to clean the surface of the evaporation boat to improve the adhesion and quality of the film. The plasma cleaning process parameters are: argon flow rate 60sccm, cleaning time 5min, RF power 800W, and argon is filled for 2min before turning on the RF power to allow the gas to fill the entire reaction chamber and maintain stable constant vacuum for cleaning.

[0044] Step 2: Evaporation boat coating

[0045] Place the evaporation boat at the bottom of the copper base of the reaction chamber (cathode), place the evaporation boat substrate in the reaction chamber and keep a distance of 24 cm between the evaporation boat substrate and the anode plate (retractable and movable) to evacuate. Before film formation begins, close the high vacuum valve (the low vacuum valve of the previous chamber is opened at this time) to keep the chemical vapor deposition chamber in a constant vacuum and positive pressure state. The carbon-containing gases butane, nitrogen, and argon are introduced into the reaction nozzle together and inflated for 2 minutes to fill the entire reaction chamber with the mixed gas, wherein the butane flow rate is 95sccm, the argon flow rate is 65sccm, and the nitrogen flow rate is 15sccm. After 2 minutes, turn on the RF power supply for coating, the RF power supply power is 1500W, the coating time is 240min, and the pressure during coating is greater than the external environment pressure of 1000Pa. Deposit the DLC coating on the evaporation boat substrate. After the deposition is completed, cool for 45 minutes to obtain the coated evaporation boat.

[0046] Example 6: A method for preparing a hard film on the surface of a boron nitride evaporation boat, specifically comprising:

[0047] Step 1: Evaporation Boat Pretreatment

[0048] First, use ultrasonic cleaning to remove impurities, dust and other pollutants on the surface of the evaporation boat, and then use CVD equipment to use plasma to clean the surface of the evaporation boat to improve the adhesion and quality of the film. The plasma cleaning process parameters are: argon flow rate 60sccm±5, cleaning time 5min, RF power supply power 800W±10, and argon is filled for 2min before turning on the RF power to allow the gas to fill the entire reaction chamber and maintain stable constant vacuum for cleaning.

[0049] Step 2: Evaporation boat coating

[0050] Place the evaporation boat at the bottom of the copper base of the reaction chamber (cathode), place the evaporation boat substrate in the reaction chamber and keep a distance of 25 cm between the evaporation boat substrate and the anode plate (retractable and movable) to evacuate. Before film formation begins, close the high vacuum valve (the low vacuum valve of the previous chamber is opened at this time) to keep the chemical vapor deposition chamber in a constant vacuum and positive pressure state. The carbon-containing gases butane, nitrogen, and argon are introduced into the reaction nozzle together and inflated for 2 minutes to fill the entire reaction chamber with the mixed gas, wherein the butane flow rate is 95sccm, the argon flow rate is 65sccm, and the nitrogen flow rate is 15sccm. After 2 minutes, turn on the RF power supply for coating, the RF power supply power is 1500W, the coating time is 240min, and the pressure during coating is greater than the external environment pressure of 1000Pa. Deposit the DLC coating on the evaporation boat substrate. After the deposition is completed, cool for 45 minutes to obtain the coated evaporation boat.

[0051] Detection experiment:

[0052] Coated evaporation boats were prepared using the methods for preparing a hard thin film on the surface of a boron nitride evaporation boat described in Example 1, Example 2, Example 3, Example 4, Example 5, and Example 6, respectively, and an uncoated evaporation boat was used as a control example. Evaporation experiments were carried out on each of the substrates using 6um PET material, and the substrate was passed into a vacuum evaporation device for evaporation.

[0053] The evaporation process is as follows:

[0054] 1. Set the equipment to vacuum, observe the vacuum value and record it until the background vacuum value (5.0e - pa);

[0055] 2. Set the cold drum temperature to -10° and the deep cooling temperature to -140°;

[0056] 3. Set the process parameters: winding tension 240N, unwinding tension 200N, wire feeding speed 370mm / min, coating speed 10m / min, bias voltage 500V, ion source 1000w, etc.;

[0057] 4. Observe the wire feeding amount and the operation of the evaporation boat (i.e. the state of the molten pool) in the equipment, adjust the wire feeding speed and the evaporation boat current in time, start winding after the evaporation and wire feeding in the coating chamber are stable, start coating when the winding speed reaches the process setting speed, and record the evaporation current and other parameters during coating;

[0058] 5. The equipment will automatically stop when the set coil diameter and length parameters are reached. When the winding stops automatically, the baffle will be automatically closed, the evaporation boat will be automatically shut down, the wire feeding will be automatically shut down, the vacuum pumping will be stopped, and the air will be automatically released. After the vacuum chamber is completely exhausted, the vacuum chamber will be opened and the parameters such as the coil length and the time of exiting the warehouse will be recorded.

[0059] After the aluminum film is evaporated, the evaporated aluminum film is scanned and detected using a CCD scanning device in the atmosphere to compare the performance of the aluminum films evaporated using different evaporation boats.

[0060] The CCD scanning operation steps are as follows:

[0061] 1. Roll up;

[0062] 2. According to the tape threading diagram, thread the membrane;

[0063] 3. Set the rewinding and unwinding tension to 120N for 1650mm wide base film and the detection speed to 70m / min;

[0064] 4. Turn on the CCD scanning instrument, turn on the strong light, start the scanning software, and set the scanning detection width to 1550mm;

[0065] 5. Start winding, the film roll begins to rewind and scan;

[0066] 6. Analyze the data of aluminum splash, pinhole distribution location, size and quantity.

[0067] When analyzing the size and quantity of the two defects, aluminum splash and pinhole, the aluminum splash is classified into aluminum splash G1, aluminum splash G2, aluminum splash G3, and aluminum splash G4, where aluminum splash G1 represents aluminum splash with an area of ​​less than 200μm, aluminum splash G2 represents aluminum splash with an area of ​​200-500μm, aluminum splash G3 represents aluminum splash with an area of ​​500-2000μm, and aluminum splash G4 represents aluminum splash with an area of ​​more than 2000μm; similarly, the pinholes are classified into pinholes G1, pinholes G2, pinholes G3, and pinholes G4, where pinhole G1 represents pinholes with an area of ​​less than 200μm, pinholes G2 represent pinholes with an area of ​​200-500μm, pinholes G3 represent pinholes with an area of ​​500-2000μm, and pinholes G4 represent pinholes with an area of ​​more than 2000μm.

[0068]

[0069]

[0070] Conclusion: According to the test data, it can be seen that the defects such as aluminum splashing and pinholes generated by the boron nitride evaporation boat prepared by the method of Example 1 during use are better in quantity and size than those of the comparative example. Depositing a hard DLC coating on a boron nitride evaporation boat can effectively improve the problems such as aluminum splashing and pinholes that occur when the evaporation boat is in use.

[0071] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a hard film on the surface of a boron nitride evaporation boat, characterized in that: Specifically: After the evaporation boat is pretreated, a mixed gas of butane, nitrogen and argon is introduced under vacuum, and a DLC coating is deposited on the evaporation boat substrate using plasma deposition technology, and then cooled to obtain a coated evaporation boat.

2. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 1, characterized in that: The method for pretreatment of the evaporation boat is: First use ultrasonic cleaning to remove dust and impurities on the surface of the evaporation boat, and then perform plasma cleaning.

3. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 2, characterized in that: The plasma cleaning parameters are as follows: argon gas is filled for 1 to 2 minutes before the RF power is turned on, the argon gas flow rate is 55 to 65 sccm, the RF power is 790 to 810 W, and the cleaning time is 3 to 10 minutes.

4. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 1, characterized in that: Before depositing the DLC coating, a mixture of butane, nitrogen and argon is first filled in for 1 to 2 minutes, with a butane flow rate of 93 to 97 sccm, an argon flow rate of 63 to 67 sccm, and an argon flow rate of 13 to 17 sccm.

5. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 1, characterized in that: When depositing the DLC coating, the distance between the evaporation boat and the anode is 20 cm to 25 cm.

6. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 1, characterized in that: When depositing the DLC coating, the RF power is 1490-1510W, the coating time is 220-260min, and the pressure during coating is 1-1000Pa greater than the external environment pressure.

7. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 1, characterized in that: After depositing the DLC coating, cool down, and the cooling time is 30min to 60min.

8. The method for preparing a hard film on the surface of a boron nitride evaporation boat according to claim 1, characterized in that: When plasma technology is used to deposit DLC coatings, 1 to 50 evaporation boats can be processed simultaneously, with the intervals between the evaporation boats being 10 mm to 15 mm.

9. A coating evaporation boat, wherein the coating thickness is 0.05 mm to 0.1 mm, made according to the method of claims 1 to 8.

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