CN114703465B - Method for improving adhesion of PECVD (plasma enhanced chemical vapor deposition) fluorocarbon coating on gold surface - Google Patents

Abstract

The invention relates to the technical field of vapor deposition, in particular to a method for improving the adhesion of a PECVD (plasma enhanced chemical vapor deposition) fluorocarbon coating on a gold surface. The adhesion of the coating to the gold surface can be significantly improved.

Description

Method for improving adhesion of PECVD (plasma enhanced chemical vapor deposition) fluorocarbon coating on gold surface

Technical Field

The invention relates to the technical field of vapor deposition, in particular to a method for improving the adhesion of a PECVD (plasma enhanced chemical vapor deposition) fluorocarbon coating on a gold surface.

Background

The plasma enhanced chemical vapor deposition (PECVD for short) introduces an excitation process of plasma on precursor gas molecules, so that the precursor molecules are in a higher energy level, deposition and film forming reactions are convenient to occur under a milder condition, the reaction is mild, and the method is environment-friendly and is one of the best choices for the surface coating protection of metal materials. Fluorocarbon coatings are always the best choice for PECVD (plasma enhanced chemical vapor deposition) protective coatings due to the advantages of excellent corrosion resistance, hydrophobicity, weather resistance and the like. But the fluorocarbon is a typical inert compound, and has poor interaction with other materials, so that the problem of poor adhesion between the coating and a substrate is caused, and the application of the fluorocarbon coating is limited.

Gold is a chemically stable metal with weak affinity to other elements and lower interaction with fluorocarbons, so that fluorocarbon coatings deposited directly on the gold surface have substantially no adhesion and can be easily peeled off.

At present, most of the vapor deposition of PECVD adopts fluorocarbon gas as a material source for deposition reaction, and the formed fluorocarbon deposition film layer can form an effective hydrophobic film coating on the surface of the material, so that the protective effect is good. However, in the case of an inert metal such as gold, since the interaction force between the coating and the metal is poor, the coating is easily separated from the metal at the interface, so that the integrity of the coating is affected, and the protection is lost, so that how to effectively improve the adhesion between the coating and the metal surface in the process is one of the important factors for providing protection.

Disclosure of Invention

The invention aims to provide a method for improving the adhesion of a PECVD (plasma enhanced chemical vapor deposition) fluorocarbon coating on a gold surface, and solves the technical problems that in the prior art, for inert metals such as gold, the coating and the metals have poor interaction force, so that the separation is easily generated at an interface to influence the integrity of the coating, cause protection failure and the like.

The invention discloses a method for improving the adhesion of a PECVD fluorocarbon coating on a gold surface, which comprises the following steps of firstly depositing a transition layer on the surface of a protected sample, and then depositing a protective layer outside the transition layer.

Further, the transition layer is a fluoropolymer with polarity.

Further, the fluorine-containing polymer with polarity is hexafluoroisopropanol or hexafluoropropylene oxide.

Further, the transition layer is injected into the vacuum plasma cavity by a liquid phase vaporization method.

Furthermore, the material of the transition layer is heated and then deposited.

Further, the deposition thickness of the transition layer is 10-100nm.

Further, the protective layer is a fluorocarbon coating.

Further, the fluorocarbon coating is formed by deposition polymerization of hexafluoropropane, hexafluoropropylene or tetrafluoroethylene.

Further, the deposition thickness of the protective layer is 1-10 μm.

Further, the protected sample is an inert metal.

Further, the inert metal is gold.

Further, the method comprises the following steps,

s1, placing a protected metal sample in a vacuum plasma chamber, and vacuumizing to 1.4 x 10 ¹ Pa；

S2, introducing argon gas of 100sccm, discharging, cleaning, and repeating the operation once;

s3, injecting a transition layer material, carrying out discharge reaction, and then stopping injecting the transition layer material;

the gold surface will generate oligomers of hexafluoroisopropanol, reacting as follows:

wherein n is an integer of 2 to 5

S4, injecting a protective layer material, and carrying out discharge reaction, wherein the protective layer material monomer is subjected to the following reaction:

on the gold surface, due to the presence of hexafluoroisopropanol oligomers, the following reactions will also take place:

wherein n is an integer of 2-5, and m is an integer greater than 1;

stopping injecting the protective layer material after the reaction reaches the specified time;

and S5, closing the vacuum, and taking out the sample after air bleeding to finish deposition.

Compared with the prior art, the invention has the beneficial effects that:

1. the adhesion of the coating to the gold surface can be significantly improved.

2. Improve the corrosion resistance and oxidation resistance of the gold surface

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments.

Example 1

A method for improving the adhesion of PECVD fluorocarbon coating on gold surface includes such steps as putting the gold-plated PCB as substrate in vacuum plasma chamber, vacuumizing to 1.4X 10% ¹ Pa；

S2, discharging for 1min after argon is introduced for 100sccm, cleaning, and repeating the operation once, wherein the input voltage is 148V, and the input current is 0.5A;

and S3, heating the hexafluoroisopropanol to 60 ℃, injecting the hexafluoroisopropanol into the vacuum chamber, wherein the injection flow is 40sccm, the discharge reaction is performed for 5min, the input voltage is 148V, the input current is 0.5A, the gas injection is stopped, and the hexafluoroisopropanol oligomer is generated on the gold surface.

And S4, injecting hexafluoropropane with the flow rate of 15sccm, carrying out discharge reaction for 30min under the conditions that the input voltage is 148V and the input current is 0.5A, turning off the power supply after the specified time is reached, and stopping injecting the gas.

And S5, closing the vacuum, and taking out the sample after air bleeding to finish deposition.

Different adhesion results can be obtained by changing the flow rate of hexafluoropropane, and the results are shown in the table I by comparing with a single fluorocarbon coating.

Example 2

As a preferred embodiment of the present application, the difference of embodiment 1 is that the discharging time for injecting hexafluoroisopropanol is 10min.

Example 3

As a preferred embodiment of the present application, the only change of embodiment 1 is that the discharging time for injecting hexafluoroisopropanol is 20min.

Different adhesion results can be obtained by changing the discharge time of introducing hexafluoroisopropanol, and the results are shown in table 1 by comparing the results with the single fluorocarbon coating.

TABLE 1 Effect of the discharge time with hexafluoroisopropanol on adhesion

Example 4

S1, placing a protected gold-plated PCB as a base material in a vacuum plasma chamber, and vacuumizing to 1.4 x 101Pa;

s2, discharging for 1min after argon is introduced for 100sccm, cleaning, and repeating the operation once, wherein the input voltage is 148V, and the input current is 0.5A;

and S3, heating the hexafluoroisopropanol to 60 ℃, injecting into a vacuum chamber, discharging for 5min at the flow rate of 40sccm and the input voltage of 148V and the input current of 0.5A, and generating an oligomer of the hexafluoroisopropanol on the surface of gold.

And S4, injecting hexafluoropropane with the flow rate of 15sccm, carrying out discharge reaction for 10min, wherein the input voltage is 148V, the input current is 0.5A, turning off the power supply after the specified time, and stopping injecting the gas.

And S5, closing the vacuum, and taking out the sample after air bleeding to finish deposition.

Example 5

As a preferred embodiment of the present application, it is modified from embodiment 4 only that the discharge time (deposition time) for injecting hexafluoropropane is 30min.

Example 6

As a preferred embodiment of the present application, it is modified from embodiment 4 only that the discharge time (deposition time) for injecting hexafluoropropane is 60min.

Varying the time of deposition polymerization of the injected hexafluoropropane results in different adhesion and different deposition thickness, as shown in tables 3-5.

Comparative example 1

In one embodiment, the single fluorocarbon deposited coating is as follows:

a gold-plated PCB is selected as a base material and is placed in the reaction cavity. Starting a vacuum pump to vacuumize until the air pressure reaches 1.4 × 101Pa, introducing 100sccm argon, discharging for 1min, cleaning, and repeating the operation once; introducing 10sccm of hexafluoropropane gas; then switching on a power supply to discharge for 30min, turning off the discharge power supply after a specified time is reached, and recovering the air pressure to the atmospheric pressure; and opening the cavity and taking out the gold-plated PCB.

Comparative example 2

In one embodiment, the single fluorocarbon deposited coating is as follows:

a gold-plated PCB is selected as a base material and is placed in the reaction cavity. Starting a vacuum pump to vacuumize until the air pressure reaches 1.4 × 101Pa, introducing 100sccm argon, discharging for 1min, cleaning, and repeating the operation once; introducing 15sccm of hexafluoropropane gas; then switching on a power supply to discharge for 30min, turning off the discharge power supply after the specified time is reached, and recovering the air pressure to the atmospheric pressure; and opening the cavity and taking out the gold-plated PCB.

TABLE 2 Effect of different deposition times on adhesion

TABLE 3 Effect of different deposition times on coating thickness

TABLE 4 influence of different gas flows on adhesion

Tables 1-4 adhesion was tested according to the method specified in GB/T9286-2020.

Tables 1-4 reflect the comparison of the adhesion capability between the PECVD fluorocarbon coating and the gold matrix under different conditions, and the longer the hexafluoroisopropanol vapor of the transition layer is introduced, the larger the thickness of the transition layer is, so that the relationship between the thickness and the adhesion of the transition layer is actually reflected in table 1, and according to the results, the transition layer can provide good adhesion to the fluorocarbon protective layer; table 2 also reflects the relationship between the deposition time of the protective layer and the adhesion, which indicates that the deposition time does not adversely affect the adhesion in the presence of the adhesion coating; table 3 shows the relationship between deposition time and coating thickness, and the longer the deposition time, the greater the thickness, and the general reaction rule is satisfied. It can be seen from table 4 that, in the absence of the transition layer, the fluorocarbon coating has substantially no adhesion to the gold substrate regardless of the process conditions, and after the transition layer is introduced, the adhesion of the coating to the substrate is 0 grade in a wide process range.

The above embodiments are just exemplified in the present embodiment, but the present embodiment is not limited to the above alternative embodiments, and those skilled in the art can obtain other various embodiments by arbitrarily combining with each other according to the above embodiments, and any other various embodiments can be obtained by anyone in light of the present embodiment. The above detailed description should not be construed as limiting the scope of the present embodiments, which should be defined in the appended claims, and the description should be used for interpreting the claims.

Claims (7)

1. A method for improving the adhesion of a PECVD fluorocarbon coating on a gold surface is characterized in that: firstly depositing a transition layer on the surface of a protected sample, and then depositing a protective layer outside the transition layer, wherein the transition layer is a fluorine-containing polymer with polarity, and the fluorine-containing polymer with polarity is hexafluoroisopropanol or hexafluoropropylene oxide.

2. The method of claim 1, wherein the method comprises the steps of: the transition layer is injected into the vacuum plasma cavity by a liquid phase vaporization method.

3. A method of improving the adhesion of PECVD fluorocarbon coatings to gold surfaces as claimed in claim 2, wherein: the material of the transition layer is heated and vaporized and then injected for deposition and polymerization.

4. The method of claim 1, wherein the method comprises the steps of: the deposition thickness of the transition layer is 10-100nm.

5. The method of claim 1, wherein the method comprises the steps of: the fluorocarbon coating is formed by deposition polymerization of hexafluoropropane, hexafluoropropylene or tetrafluoroethylene.

6. The method of claim 1, wherein the method comprises the steps of: the deposition thickness of the protective layer is 1-10 μm.

7. The method of claim 1, wherein the method comprises the steps of: the method further comprises the step of providing a display,

s1, placing a protected metal sample in a vacuum plasma chamber, and vacuumizing;

s2, discharging and cleaning after inert gas is introduced, and repeating the operation once;

s3, injecting a transition layer material, carrying out discharge reaction, and then stopping injecting the transition layer material;

s4, injecting a protective layer material, carrying out discharge reaction, and then stopping injecting the protective layer material;

and S5, closing the vacuum, and taking out the sample after air bleeding to finish deposition.