Film coating method for surface of flexible circuit board

Abstract

The invention discloses a flexible circuit board surface coating method, which comprises the following steps: cleaning a flexible circuit board, and placing the cleaned flexible circuit board in a reaction chamber; depositing a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board; a DLC film is deposited on a surface of the fluoride layer. According to the technical scheme of the invention, the hydrophilic fluoride layer is firstly deposited on the surface of the flexible circuit board, and then the DLC film is deposited, so that the problem caused by directly plating the DLC film on the surface of the flexible circuit board can be solved.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and more particularly to a coating method for the surface of a flexible circuit board. Background Technology

[0002] In the electronics industry, it is necessary to coat the surface of flexible circuit boards. Currently, the common method is to directly coat the surface with DLC (Diamond-like Carbon) film. However, the problem is that directly coating the surface of flexible circuit boards with DLC film will cause the surface of the flexible circuit boards to curl, which will affect the subsequent processing and subsequent applications in daily life. Summary of the Invention

[0003] The purpose of this invention is to provide a coating method for the surface of a flexible circuit board. By first depositing a hydrophilic fluoride layer on the surface of the flexible circuit board, and then depositing a DLC film, the problem of directly depositing a DLC film on the surface of the flexible circuit board can be solved.

[0004] To achieve the above objectives, embodiments of the present invention provide a coating method for the surface of a flexible circuit board, comprising:

[0005] The flexible circuit board is cleaned and then placed in the reaction chamber.

[0006] A hydrophilic fluoride layer is deposited on the surface of the cleaned flexible circuit board;

[0007] A DLC film is deposited on the surface of the fluoride layer.

[0008] Furthermore, the deposition of a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board specifically involves:

[0009] Under the conditions of a first preset temperature and a first preset pressure, a hydrophilic fluoride is used to chemically react with the surface of the cleaned flexible circuit board to form a hydrophilic fluoride layer.

[0010] Furthermore, the first preset temperature is 600℃~750℃, and the first preset pressure is 3.0~4.5kPa.

[0011] Furthermore, the deposition time of the fluoride layer is 10–20 min.

[0012] Further, the deposition of a DLC film on the surface of the fluoride layer specifically involves:

[0013] A mixture of methyl methacrylate and hydrogen is added to the reaction chamber as a precursor gas;

[0014] Using a chemical vapor deposition method, under the conditions of a second preset temperature and a second preset pressure, the precursor gas undergoes a chemical reaction on the surface of the fluoride layer and is deposited to form a DLC film.

[0015] Furthermore, the second preset temperature is 400℃~450℃, and the second preset pressure is 1.5~2.0kPa.

[0016] Furthermore, the deposition time of the DLC film is 3 to 5 minutes.

[0017] Furthermore, the method also includes:

[0018] During the deposition of the DLC film, isooctyltrimethylsilane is added into the reaction chamber;

[0019] The second preset temperature is adjusted to the third preset temperature, and the second preset pressure is adjusted to the third preset pressure, and the deposition process of the DLC film continues.

[0020] Furthermore, the flow rate of the isooctyltrimethylsilane is 3.5% to 5.0% of the total gas flow rate.

[0021] Furthermore, the third preset temperature is 300℃~500℃, and the third preset pressure is 0.5~1.0kPa.

[0022] Compared with existing technologies, this invention provides a coating method for the surface of a flexible circuit board. First, the flexible circuit board is cleaned and placed in a reaction chamber. Then, a hydrophilic fluoride layer is deposited on the surface of the cleaned flexible circuit board. Finally, a DLC film is deposited on the surface of the fluoride layer. This invention solves the problems associated with directly depositing DLC ​​films on the surface of flexible circuit boards by first depositing a hydrophilic fluoride layer and then depositing the DLC film. Attached Figure Description

[0023] Figure 1 This is a flowchart of a preferred embodiment of a coating method for the surface of a flexible circuit board provided by the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention provides a coating method for the surface of a flexible circuit board, see [link to relevant documentation]. Figure 1 The diagram shown is a flowchart of a preferred embodiment of a coating method for the surface of a flexible circuit board provided by the present invention, the method comprising steps S11 to S13:

[0026] Step S11: Clean the flexible circuit board and place the cleaned flexible circuit board in the reaction chamber;

[0027] Step S12: Deposit a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board;

[0028] Step S13: Deposit a DLC film on the surface of the fluoride layer.

[0029] In practice, firstly, the flexible circuit board is cleaned to ensure it is clean, and then the cleaned flexible circuit board is placed in the reaction chamber. Next, a stable hydrophilic fluoride layer is deposited on the surface of the cleaned flexible circuit board. Finally, a DLC film is deposited on the surface of the hydrophilic fluoride layer.

[0030] It should be noted that there is a hydrophilic fluoride layer between the DLC film and the flexible circuit board, which makes the bonding strength between the DLC film and the flexible circuit board good, and the DLC film is not easy to peel off. Furthermore, by depositing a hydrophilic fluoride layer, the affinity between the DLC film and water can be enhanced, making the surface of the DLC film less likely to adsorb moisture.

[0031] In one optional embodiment, the deposition of a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board specifically involves:

[0032] Under the conditions of a first preset temperature and a first preset pressure, a hydrophilic fluoride is used to chemically react with the surface of the cleaned flexible circuit board to form a hydrophilic fluoride layer.

[0033] Specifically, in conjunction with the above embodiments, when depositing a hydrophilic fluoride layer on the surface of a cleaned flexible circuit board, a hydrophilic fluoride (such as fluoropropane) can be used to chemically react with the surface of the cleaned flexible circuit board under reaction conditions where the temperature in the reaction chamber is a first preset temperature and the pressure is a first preset pressure, forming a hydrophilic fluoride compound covering the surface of the cleaned flexible circuit board, thereby depositing and forming a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board.

[0034] In one optional embodiment, the first preset temperature is 600°C to 750°C, and the first preset pressure is 3.0 to 4.5 kPa.

[0035] Specifically, in conjunction with the above embodiments, when depositing a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board, the first preset temperature can be 600℃~750℃, and the first preset pressure can be 3.0kPa~4.5kPa. That is, under the reaction conditions of 600℃~750℃ and 3.0kPa~4.5kPa in the reaction chamber, a hydrophilic fluoride (such as fluoropropane) is used to chemically react with the surface of the cleaned flexible circuit board, thereby depositing and forming a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board.

[0036] For example, the first preset temperature can be 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃ or 750℃, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0037] For example, the value of the first preset pressure can be 3.0 kPa, 3.1 kPa, 3.2 kPa, 3.3 kPa, 3.4 kPa, 3.5 kPa, 3.6 kPa, 3.7 kPa, 3.8 kPa, 3.9 kPa, 4.0 kPa, 4.1 kPa, 4.2 kPa, 4.3 kPa, 4.4 kPa or 4.5 kPa, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0038] In one optional embodiment, the deposition time of the fluoride layer is 10 to 20 minutes.

[0039] Specifically, in conjunction with the above embodiments, when depositing a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board, the deposition time of the fluoride layer can be 10 min to 20 min. That is, under reaction conditions of 600℃ to 750℃ and 3.0 kPa to 4.5 kPa in the reaction chamber, a hydrophilic fluoride (such as fluoropropane) is used to chemically react with the surface of the cleaned flexible circuit board, and the reaction time is 10 min to 20 min, thereby depositing and forming a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board.

[0040] For example, the deposition time of the fluoride layer can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0041] In one optional embodiment, the deposition of the DLC film on the surface of the fluoride layer specifically involves:

[0042] A mixture of methyl methacrylate and hydrogen is added to the reaction chamber as a precursor gas;

[0043] Using a chemical vapor deposition method, under the conditions of a second preset temperature and a second preset pressure, the precursor gas undergoes a chemical reaction on the surface of the fluoride layer and is deposited to form a DLC film.

[0044] Specifically, in conjunction with the above embodiments, when depositing a DLC film on the surface of a hydrophilic fluoride layer, a mixture of methyl methacrylate and hydrogen can be added to the reaction chamber first to form a precursor gas for the DLC film. Then, the temperature in the reaction chamber is adjusted from a first preset temperature to a second preset temperature, and the pressure in the reaction chamber is adjusted from a first preset pressure to a second preset pressure. Using the chemical vapor deposition (CVD) method, under the reaction conditions of the second preset temperature and the second preset pressure in the reaction chamber, the precursor gas undergoes a chemical reaction on the surface of the hydrophilic fluoride layer, and a DLC film is deposited on the surface of the hydrophilic fluoride layer.

[0045] In one optional embodiment, the second preset temperature is 400°C to 450°C, and the second preset pressure is 1.5 to 2.0 kPa.

[0046] Specifically, in conjunction with the above embodiments, when depositing a DLC film on the surface of a hydrophilic fluoride layer, the second preset temperature can be 400℃~450℃, and the second preset pressure can be 1.5kPa~2.0kPa. That is, a mixture of methyl methacrylate and hydrogen can be added to the reaction chamber first to form a precursor gas for the DLC film. Then, the temperature in the reaction chamber is adjusted from 600℃~750℃ to 400℃~450℃, and the pressure in the reaction chamber is adjusted from 3.0kPa~4.5kPa to 1.5kPa~2.0kPa. Using a chemical vapor deposition method, under the reaction conditions of a temperature of 400℃~450℃ and a pressure of 1.5kPa~2.0kPa in the reaction chamber, the precursor gas undergoes a chemical reaction on the surface of the hydrophilic fluoride layer, and a DLC film is deposited on the surface of the hydrophilic fluoride layer.

[0047] For example, the second preset temperature can be 400℃, 405℃, 410℃, 415℃, 420℃, 425℃, 430℃, 435℃, 440℃, 445℃ or 450℃, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0048] For example, the value of the second preset pressure can be 1.5 kPa, 1.6 kPa, 1.7 kPa, 1.8 kPa, 1.9 kPa or 2.0 kPa, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0049] In one optional embodiment, the deposition time of the DLC film is 3 to 5 minutes.

[0050] Specifically, in conjunction with the above embodiments, when depositing a DLC film on the surface of a hydrophilic fluoride layer, the deposition time of the DLC film can be 3 min to 5 min. That is, a mixture of methyl methacrylate and hydrogen can be added to the reaction chamber first to form a precursor gas for the DLC film. Then, the temperature in the reaction chamber is adjusted from 600℃ to 750℃ to 400℃ to 450℃, and the pressure in the reaction chamber is adjusted from 3.0 kPa to 4.5 kPa to 1.5 kPa to 2.0 kPa. Using the chemical vapor deposition method, under the reaction conditions of a temperature of 400℃ to 450℃ and a pressure of 1.5 kPa to 2.0 kPa in the reaction chamber, the precursor gas undergoes a chemical reaction on the surface of the hydrophilic fluoride layer, and a DLC film is deposited on the surface of the hydrophilic fluoride layer, with a deposition time of 3 min to 5 min.

[0051] For example, the deposition time of the DLC film can be 3 minutes, 3 minutes 10 seconds, 3 minutes 20 seconds, 3 minutes 30 seconds, 3 minutes 40 seconds, 3 minutes 50 seconds, 4 minutes, 4 minutes 10 seconds, 4 minutes 20 seconds, 4 minutes 30 seconds, 4 minutes 40 seconds, 4 minutes 50 seconds, or 5 minutes. It can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0052] In one alternative embodiment, the method further includes:

[0053] During the deposition of the DLC film, isooctyltrimethylsilane is added into the reaction chamber;

[0054] The second preset temperature is adjusted to the third preset temperature, and the second preset pressure is adjusted to the third preset pressure, and the deposition process of the DLC film continues.

[0055] Specifically, in conjunction with the above embodiments, during the deposition of DLC films using chemical vapor deposition, isooctyltrimethylsilane (TMAI) can be added to the reaction chamber after the DLC film has been deposited for a period of time. The temperature in the reaction chamber is adjusted from the second preset temperature to the third preset temperature, and the pressure in the reaction chamber is adjusted from the second preset pressure to the third preset pressure. Under the reaction conditions of the third preset temperature and the third preset pressure in the reaction chamber, the deposition process of the DLC film continues until the deposition process of the DLC film is completed.

[0056] It should be noted that during the deposition of the DLC film, by adding a small amount of TMAI into the reaction chamber, it is cleaved by the carbon-hydrogen bonds in the DLC film to generate free aromatic rings, which allows the excess carbon atoms to form stronger bonds with the flexible circuit board. This can significantly reduce the residual stress of the DLC film and improve its stability.

[0057] In one optional embodiment, the flow rate of the isooctyltrimethylsilane is 3.5% to 5.0% of the total gas flow rate.

[0058] Specifically, in conjunction with the above embodiments, when TMAI is added to the reaction chamber, the flow rate of TMAI can be 3.5% to 5.0% of the total gas flow rate, wherein the total gas flow rate is the total flow rate of the precursor gas in the DLC film deposition process and the various inert gases required for DLC film deposition.

[0059] For example, the flow rate of TMAI as a percentage of the total gas flow rate can be 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, or 5.0%, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0060] In one optional embodiment, the third preset temperature is 300℃~500℃, and the third preset pressure is 0.5~1.0kPa.

[0061] Specifically, in conjunction with the above embodiments, after adding TMAI to the reaction chamber, the third preset temperature can be 300℃~500℃, and the third preset pressure can be 0.5kPa~1.0kPa. That is, the temperature in the reaction chamber can be adjusted from 400℃~450℃ to 300℃~500℃, and the pressure in the reaction chamber can be adjusted from 1.5kPa~2.0kPa to 0.5kPa~1.0kPa. Under the reaction conditions of a temperature of 300℃~500℃ and a pressure of 0.5kPa~1.0kPa in the reaction chamber, the DLC film deposition process continues until the DLC film deposition process is completed.

[0062] For example, the value of the third preset temperature can be 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃ or 500℃, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0063] For example, the value of the third preset pressure can be 0.5 kPa, 0.6 kPa, 0.7 kPa, 0.8 kPa, 0.9 kPa or 1.0 kPa, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0064] It should be noted that, in the specific implementation of the embodiments of the present invention, other additives, such as lecithin, phosphatidylcholine, glass powder, etc., may be added as needed to further enhance the performance of the DLC film.

[0065] Based on all the above embodiments, the implementation process of this solution is described below through the first specific embodiment, including: (1) cleaning the flexible circuit board to clean it thoroughly, and placing the cleaned flexible circuit board in the reaction chamber; (2) under the reaction conditions of 600°C and 3.0 kPa in the reaction chamber, using a hydrophilic fluoride (e.g., fluoropropane) to chemically react with the surface of the cleaned flexible circuit board, and the reaction time is 20 min, so as to deposit a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board; (3) first adding a mixture of methyl methacrylate and hydrogen in the reaction chamber to form the precursor gas of the DLC film, and then adjusting the temperature in the reaction chamber from 600°C to 400°C and the pressure in the reaction chamber from 3 kPa to 400°C. The pressure was adjusted from 0 kPa to 1.5 kPa, and a chemical vapor deposition (CVD) method was used. Under reaction conditions of 400°C and 1.5 kPa in the reaction chamber, the precursor gas underwent a chemical reaction on the surface of a hydrophilic fluoride layer, and a DLC film was deposited on the surface of the hydrophilic fluoride layer for 5 minutes. After the DLC film had been deposited for a period of time, a small amount of TMAI was added to the reaction chamber, with the flow rate of TMAI being 3.5% of the total gas flow rate. The temperature in the reaction chamber was adjusted from 400°C to 300°C, and the pressure in the reaction chamber was adjusted from 1.5 kPa to 0.5 kPa. Under reaction conditions of 300°C and 0.5 kPa in the reaction chamber, the DLC film deposition process continued until the DLC film deposition process was completed.

[0066] Based on all the above embodiments, the implementation process of this solution is described below through a second specific embodiment, including: (1) cleaning the flexible circuit board to clean it thoroughly, and placing the cleaned flexible circuit board in a reaction chamber; (2) under reaction conditions of 700°C and 4.0 kPa in the reaction chamber, using a hydrophilic fluoride (e.g., fluoropropane) to chemically react with the surface of the cleaned flexible circuit board, and the reaction time is 15 min, so as to deposit a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board; (3) first adding a mixture of methyl methacrylate and hydrogen in the reaction chamber to form the precursor gas of the DLC film, and then adjusting the temperature in the reaction chamber from 700°C to 425°C and the pressure in the reaction chamber from 4 kPa to 4 kPa. The pressure was adjusted from 0 kPa to 1.8 kPa, and a chemical vapor deposition (CVD) method was used. Under reaction conditions of 425°C and 1.8 kPa in the reaction chamber, the precursor gas underwent a chemical reaction on the surface of a hydrophilic fluoride layer, and a DLC film was deposited on the surface of the hydrophilic fluoride layer for 4 minutes. After the DLC film had been deposited for a period of time, a small amount of TMAI was added to the reaction chamber, with the flow rate of TMAI being 4.5% of the total gas flow rate. The temperature in the reaction chamber was adjusted from 425°C to 400°C, and the pressure in the reaction chamber was adjusted from 1.8 kPa to 0.8 kPa. The DLC film deposition process continued under reaction conditions of 400°C and 0.8 kPa until the DLC film deposition process was completed.

[0067] Based on all the above embodiments, the implementation process of this solution is described below through a third specific embodiment, including: (1) cleaning the flexible circuit board to clean it thoroughly, and placing the cleaned flexible circuit board in a reaction chamber; (2) under reaction conditions of 750°C and 4.5 kPa in the reaction chamber, using a hydrophilic fluoride (e.g., fluoropropane) to chemically react with the surface of the cleaned flexible circuit board, and the reaction time is 10 min, so as to deposit a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board; (3) first adding a mixture of methyl methacrylate and hydrogen in the reaction chamber to form the precursor gas of the DLC film, and then adjusting the temperature in the reaction chamber from 750°C to 450°C and the pressure in the reaction chamber from 4 kPa to 4 kPa. The pressure was adjusted from 0.5 kPa to 2.0 kPa, and a chemical vapor deposition (CVD) method was used. Under reaction conditions of 450°C and 2.0 kPa in the reaction chamber, the precursor gas underwent a chemical reaction on the surface of a hydrophilic fluoride layer, and a DLC film was deposited on the surface of the hydrophilic fluoride layer for 3 minutes. After the DLC film had been deposited for a period of time, a small amount of TMAI was added to the reaction chamber, with the flow rate of TMAI being 5.0% of the total gas flow rate. The temperature in the reaction chamber was adjusted from 450°C to 500°C, and the pressure in the reaction chamber was adjusted from 2.0 kPa to 1.0 kPa. Under reaction conditions of 500°C and 1.0 kPa in the reaction chamber, the DLC film deposition process continued until the DLC film deposition process was completed.

[0068] In summary, the coating method for the surface of a flexible circuit board provided by this invention involves first cleaning the flexible circuit board and then placing it in a reaction chamber; then, depositing a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board; and finally, depositing a DLC film on the surface of the fluoride layer. This invention solves the problems associated with directly depositing DLC ​​films on the surface of flexible circuit boards by first depositing a hydrophilic fluoride layer and then depositing the DLC film. Furthermore, the DLC film prepared by this invention exhibits good bonding strength, and its stress state effectively reduces the risk of microcracks on the DLC film surface caused by mechanical deformation. In addition, the method of this invention is simple, low-cost, and can produce DLC films with excellent performance, showing broad application prospects.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A coating method for the surface of a flexible circuit board, characterized in that, include: The flexible circuit board is cleaned and then placed in the reaction chamber. A hydrophilic fluoride layer is deposited on the surface of the cleaned flexible circuit board; A DLC film is deposited on the surface of the fluoride layer.

2. The coating method for the surface of a flexible circuit board as described in claim 1, characterized in that, The deposition of a hydrophilic fluoride layer on the surface of the cleaned flexible circuit board specifically involves: Under the conditions of a first preset temperature and a first preset pressure, a hydrophilic fluoride is used to chemically react with the surface of the cleaned flexible circuit board to form a hydrophilic fluoride layer.

3. The coating method for the surface of a flexible circuit board as described in claim 2, characterized in that, The first preset temperature is 600℃~750℃, and the first preset pressure is 3.0~4.5kPa.

4. The coating method for the surface of a flexible circuit board as described in claim 2, characterized in that, The deposition time of the fluoride layer is 10 to 20 minutes.

5. The coating method for the surface of a flexible circuit board as described in claim 1, characterized in that, The deposition of a DLC film on the surface of the fluoride layer specifically involves: A mixture of methyl methacrylate and hydrogen is added to the reaction chamber as a precursor gas; Using a chemical vapor deposition method, under the conditions of a second preset temperature and a second preset pressure, the precursor gas undergoes a chemical reaction on the surface of the fluoride layer and is deposited to form a DLC film.

6. The coating method for the surface of a flexible circuit board as described in claim 5, characterized in that, The second preset temperature is 400℃~450℃, and the second preset pressure is 1.5~2.0kPa.

7. The coating method for the surface of a flexible circuit board as described in claim 5, characterized in that, The deposition time of the DLC film is 3 to 5 minutes.

8. The coating method for the surface of a flexible circuit board as described in claim 5, characterized in that, The method further includes: During the deposition of the DLC film, isooctyltrimethylsilane is added into the reaction chamber; The second preset temperature is adjusted to the third preset temperature, and the second preset pressure is adjusted to the third preset pressure, and the deposition process of the DLC film continues.

9. The coating method for the surface of a flexible circuit board as described in claim 8, characterized in that, The flow rate of the isooctyltrimethylsilane is 3.5% to 5.0% of the total gas flow rate.

10. The coating method for the surface of a flexible circuit board as described in claim 8, characterized in that, The third preset temperature is 300℃~500℃, and the third preset pressure is 0.5~1.0kPa.

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