Ion Coating Black Decorative Film Recipes

- Apr 22, 2019-

Ion coating black decorative film recipes


1. Material comparison


TiC is the most common and economical hard black film. Color can accomplish deeper, wear-resisting performance is very good also, but its are tonal not quite sterling, always in black take yellow slightly. Moreover, because the melting point of titanium is relatively low, it is easy to produce large particles when sputtering, making it difficult to improve the optical sensitivity. The ability of anti - fingerprint is also not good, rub yellow, become blurry.


The overall tone of the CrC is better than that of the TiC, which is less black but more pure and whiter. Since chromium changes directly from solid state to gaseous state during sputtering, although the sputtering coefficient of chromium is very large and the deposition rate of film layer is very fast, its optical brightness is better than TiC. Fingerprint protection is also better than TiC. Cr is a brittle material, and the residual stress of the film is particularly important to the wear resistance.


TiCrAlC was tested with a small plane target, and the results showed that light sensitivity and fingerprint resistance were very good, which may have two reasons: (1) the light sensitivity and fingerprint resistance of the material itself was good; (2) use plane target bombardment. It also has good wear resistance, which may be due to: 1. (2) TiCrAlC itself is relatively wear-resistant; (3) the power density of the small plane target is relatively high, and the sputter particles have high energy, so the film is dense.


TiCrAlC was tested with a small plane target, and the results showed that light sensitivity and fingerprint resistance were very good, which may have two reasons: (1) the light sensitivity and fingerprint resistance of the material itself was good; (2) use plane target bombardment. It also has good wear resistance, which may be due to: 1. (2) TiCrAlC itself is relatively wear-resistant; (3) the power density of the small plane target is relatively high, and the sputter particles have high energy, so the film is dense.


TiCN is a film with good hardness and wear resistance. Its color can even be blacker than TiC. It is not smooth to the touch and has a sticky feeling.

2. Configuration of experimental machine

(1)Power Source

1) AE medium frequency power supply

The accuracy of AE power source is very high, the requirement for target material is not high, the self-protection ability of power source is relatively strong, so the requirement for external conditions such as vacuum degree is more stringent, easy to extinguishing. The plated CrC film has good light and fingerprint resistance, but the color is black with blue. The abrasion resistance is also the best of the tested power supplies.

2)Xinda intermediate frequency power supply

The power of the new power supply is larger, can be used in parallel with its one of the advantages. The CrC film was black but white, and the wear resistance was worse than that of AE power.

3)Sp medium frequency power supply

The stability of shengpu power supply is worse than other power supply, and the actual power is not large. The plated CrC film is slightly yellow and does not wear well.

4)Power tech medium frequency power supply

Power tech power is the largest, but in low power use when the glow is unstable, high power when the noise is larger.

5)Sheng pu DC power supply

The glow of the dc power supply was blue, indicating that the sputter particles had higher energies. However, the hysteresis effect of dc power coating is serious, and the color control is difficult.

(2)Magnetron sputtering target

1)Direct water-cooled chromium target VS indirect water-cooled chromium target

The direct water cooling target can use higher power supply because of its better cooling effect.(generally, the power density of direct cooling is 25W/cm2, and that of intercooling is 15 ~ 20W/cm2). The sputter metal particles are finer. In the test of electricity, the direct water-cooled chromium target used xinda power supply and AE power supply, while the indirect water-cooled chromium target used shengpu power supply. As a result, the CrC plated from the direct water-cooled chromium target had better performance (the power supply also had an effect). In addition, the direct water-cooled chromium target poisoning is shallow and the target washing time is short. In addition, when the indirect water-cooled chromium target was connected to the AE power supply, the glow was blue, the sputter particles had high energy, and the Cr purity was higher than that of the direct water-cooled chromium target, so it was possible to obtain better coating. When the power is 3KW and the vacuum degree is 0.1pa, it can also be used for setting experiments of column target bombardment.


Plane target VS cylinder target

A planar target cools better than a cylindrical one, so a better film is usually produced. Because the etching place of planar target is invariable, it is not easy to be poisoned, and thicker film can be obtained. The current test is the dc power supply bombardment, substrate, and then the use of power source medium frequency power coating film, the result is a few hours of film peeling, no comparison of the advantages and disadvantages of the plane target and cylindrical target. It is necessary to use arc target to bombard the substrate, and to use plane target to plating the film, to see whether the performance of the plated film is improved?


Magnetic field (non-equilibrium VS equilibrium)

The purpose of using non-equilibrium magnetic field is to expand the area of plasma, improve the energy of particles deposited on the workpiece, and thus improve the wear resistance.However, the experimental results show that the wear resistance of the film after non-equilibrium magnetic field is not significantly changed, but the light sensitivity and fingerprint resistance are decreased. According to the situation of the target surface after changing the magnetic field, the light near the target surface is weakened, and the light at the place farther away from the target is enhanced, which indicates that the area of the plasma after changing to the non-equilibrium magnetic field is indeed expanded. In addition, the bias current also increased, indicating that the ionization rate also increased.As for the voltage rise of the power supply, it may be due to the weakening of the magnetic field in general, and is not caused by non-equilibrium. Why did the experiment turn out differently than expected? I think there are several reasons as follows: a has a high degree of non-equilibrium, making the plasma region too large and the energy of the deposited particles too large.In addition, the deposition rate increases after the plasma region expands. Therefore, the optical comfort decreases, while the wear resistance does not increase significantly. When the power of b power source rises, the sputtering amount increases, the deposition rate increases, and the light order is affected. C did not get the best coating process during the electricity test, and the experimental results have some errors.


Pairs targets VS twin targets

The effect of glow discharge on the pairs target was much better than that of twin targets. According to different requirements, closed placement and mirror placement can be adopted for the target.


(3) auxiliary source (filament)

For the single-column target coating process, if there is no filament, the color of the film is not uniform, easy to colorful, light order and fingerprint effect is particularly poor; For intermediate frequency, the effect of adding filament is not obvious. In the process of coating, the flow of C2H2 increased slightly after adding the filament, indicating that the filament played a certain role in ionization, but not much. Another function of the filament is to heat the workpiece. Compared with the heating tube, the heating electron collision heating not only increases the temperature of the workpiece, but also gives the deposited atoms an initial kinetic energy, improves its diffusion ability and increases the activity of the film layer.


(3)gas pipe positions

At present, three feasible ventilation methods were proposed: 1) the trachea was placed between intermediate frequency targets to improve the ionization rate of reaction gas; 2) trachea next to a target, the purpose is to the trachea next to the target as an ionization source, the other target as a sputtering source; 3) the working gas near the sputtering target, reaction gas near the workpiece, to slow down the target poisoning.


3. Comparison of coating methods (medium frequency vs. central target +filament)

Theoretically, the ionization rate of medium frequency is much higher than that of single column target. But according to the experimental results, intermediate frequency coating does have certain advantages in color, lightness and fingerprint resistance, but in terms of wear resistance is worse.The reasons may be as follows: a from the perspective of glow, most of the glow using the medium frequency power supply is white (white light is a combination of red, orange, yellow, green, blue, lake and purple), and its energy is lower than that of the blue light generated by the dc power supply. When b USES the medium frequency power supply, it is generally oriented magnetic field, and the sputtering particles are concentrated in one direction, so its glow can be strong. The plasma is discontinuous on the track of the workpiece, and thus the film is discontinuous. Target is 360 ° and single column magnetic field, sputtering of particles were distributed evenly around the target, the particle density is not high also, is evenly distributed in the workpiece's orbit, the film growth is the continuous uniform slow growing; C medium frequency coating has a higher ionization rate and is also affected by bias pressure. The hardness of the obtained film is improved, which is conducive to the anti-fingerprint effect, while the residual stress is increased, which has an impact on the wear resistance. The two targets of d medium frequency are the Yin and Yang poles of each other. When sputtering as the cathode, the target as the anode is cooled to reduce large particles and improve light order.


Influence of process parameters

1After bias pressure is to give ions an additional energy, so that the film deposition of more dense, but the corresponding stress also increased.The ionization rate of magnetron sputtering is between 10% and 20%, compared with 20% to 40% of hot cathode and 60% to 90% of multi-arc, the ionization rate is very low.Carbon in the film comes from C2H2, while C2H2 can only be deposited in the film after being ionized into C+ and CH+ (few C2H2 are mixed with the film), so element C in the film is affected by bias before being deposited on the workpiece.When the bias is high, the backsplash of C+ than the metal ions to make the overall color of the film lighter.In addition, with the increase of bias, the hardness of the film increases, which is conducive to the anti-fingerprint effect of the film, but is not conducive to the lightness.


(2)The duty ratio can be understood as the coating to the workpiece bias time, the larger the duty ratio, the overall applied to the ion energy is greater, improve the hardness of the film, is conducive to the ability to prevent fingerprint, but too high duty ratio is easy to spark.

(3)As mentioned above, the ionization rate of magnetron sputtering is low, resulting in less additional energy applied by bias voltage. Therefore, the initial energy of sputtering particles and the energy loss of particles before they are deposited on the workpiece become more important. The larger the power source is, the larger the initial energy of sputtering particles will be. So high power is conducive to the wear resistance of the film.

(4)The higher the vacuum of the coating, the less the collision times of the particles, the less the energy loss of the particles, and the better the abrasion resistance of the coating. At present, the relatively popular low-pressure film forming method has a vacuum degree less than or equal to 0.1pa, and the target material is etched more evenly when the vacuum degree is high.

(5)Target base distance with a single column target filament process, the use of 12 rod of the large turning frame electric TiC, the result is that the light degree and anti fingerprint effect has been significantly improved, and the color is also to 8 rod than the small turning frame to black some, not so yellow, but a lot of poor wear resistance.

(6)The flow control of C2H2 has a great influence on the performance of the film. Generally speaking, the first fast and then slow way is adopted. C2H2 flow into the beginning is too large, the film is easy to colorful, and the stress is large, not wear-resistant; At the beginning, the flow of C2H2 is too small, and the hardness of the film decreases. It is not wear-resistant, and the time is long. The light condition is not good. Generally at the beginning of C2H2 flow at the end of coating C2H2 flow of about one-third of the good.

The parameters mentioned above plus the magnetic field of the sputtering target are the most important factors affecting the deposition ion energy and residual stress of the film. Only they match reasonably, can obtain the best coating technology, get the best film quality.

(7)TiN transition layer the purpose of adding TiN transition layer is to add a hard lower layer and obtain a more wear-resistant film layer. However, the experimental results show that the wear resistance of single-post target filament process with TiN transition layer is improved, but there is no significant change for the intermediate frequency coating process. It may be because the film hardness of single column target filament process is not as high as that of the intermediate frequency process. In addition, the time of TiN transition layer is relatively short, which does not play the role of adding hard bottom layer.

(8)Background vacuum the higher the background vacuum, the less impurities introduced when coating, so that the color of the film more pure.

(9)Time coating time is too long, will make the film of light order and anti-fingerprint effect is reduced, and, the increase in time, film thickness, stress will increase, may make wear resistance decreased.

(10)The metal transition layer is required to bombard the workpiece before coating to remove the oxide layer on the surface. The bombarding particle backsplash (energy at 100eV) is required. High bias voltage is required to apply additional energy to the ions. However, magnetron sputtering (generally, the initial energy of particles is 2 ~ 20eV) has low ionization rate, less ions generated, less additional energy applied by bias voltage and difficulty in removing the oxide layer. The deposited metal transition layer (soft layer) ACTS as a shear band, allowing a certain "relative slip" between the matrix and the TiC at a low stress level. But too thick metal transition layer will soften the matrix and reduce the wear resistance.

(11)In addition, Ar can replace the adsorbed gas of the workpiece and improve the background vacuum. Due to the small effect, the test did not see obvious effect.

(12)After the completion of the coating cleaning cleaning may remove the free C film, improve the film fingerprint effect. But whether it has such effect remains to be tested.

IKS PVDion sourcemedium frequency sputtering coating