KR20020078618A - Inductively Coupled Plasma Assisted Sputtering System with Multiple Coils And Method Thereby - Google Patents

Abstract

PURPOSE: A multi-coil type ICP(Inductive Coupling Plasma) magnetron sputtering system and a method for the same are provided to improve durability of a coating body by forming a membrane of high hardness. CONSTITUTION: A rotary jig(12) is installed in a center of a chamber(10). A substrate is loaded on the rotary jig(12). A plurality of DC magnetrons(20a,20b) is loaded on both sides of the substrate in order to sputter a plurality of targets(14a,14b). A plurality of RFI(Radio Frequency Inductively coupled) coils(30a,30b) is installed on the DC magnetrons(20a,20b). The RFI coils(30a,30b) are used as ICP generators. The substrate is loaded on the rotary jig(12). Plasma is activated by installing the RFI coils(30a,30b) between the sputtering targets(14a,14b) and the substrate. A plurality of DC power supply portions(27a,27b) is used for supplying DC power to the targets(14a,14b). An ICP is generated between the sputtering targets(14a,14b) and the substrate.

Description

Inductively Coupled Plasma Assisted Sputtering System with Multiple Coils And Method Thereby

The present invention relates to a multi-coil inductively coupled plasma magnetron sputtering system and a method thereof, and to a multi-coiled inductively coupled plasma magnetron sputtering system and method for the production of ultra-hard wear and decorative coating.

In general, an internally inductively coupled plasma (ICP) sputtering method is a method in which a copper plasma, a new plasma assist device, is wound in a circular or spiral manner and mounted directly in the reactor to activate the plasma inside the reactor. Technology.

Applying RF power to a water-cooled copper coil mounted inside the reactor causes a sudden change in the electric field and creates a magnetic field in the axial direction of the coil. The secondary electric field is induced around the coil under the influence of the magnetic field that changes with time, and the induced electric field causes the electrons to accelerate in a circular motion along the coil around the coil. Secondary ionization.

Therefore, the plasma in the reactor is further activated, and the ionization rate of the particles is drastically increased than the conventional magnetron sputtering. Magnetron sputtering, which is currently commercially available and widely used in the deposition process, can increase the particle ionization rate by less than 10%, while increasing ICP-sputtering by about 80%.

In addition, in the general magnetron sputtering method, all the electrons participating in the ionization are bound to the leakage magnetic field installed at the cathode and thus cannot fly to the substrate. Therefore, the number of ions that have an acceleration effect even when a negative bias is applied to the substrate is obtained. Since there is very little near the substrate, the filling effect by the ions was hardly obtained.

Therefore, a technique developed as a method for extending the plasma in the vicinity of the cathode to the periphery of the substrate is internally inserted inductively coupled plasma sputtering. The principle of the device using inductively coupled plasma was developed in 1920. The existing ICP device uses an ICP antenna installed outside the dielectric window (quartz, alumina) to indirectly transmit high frequency power. However, a fatal drawback of such external ICP devices is that if a conductive material (metal, TiN, etc.) is coated on the inside of the window, no power can be delivered to maintain plasma.

Therefore, some of the developed equipment is currently only applied to the dielectric thin film. In addition, there is a lot of difficulties in the application to the enlargement because the maintenance of the need to continuously clean the internal dielectric material and the mechanical strength in the production and maintenance of large area dielectric window becomes a problem.

On the other hand, the deposition process using the internal insertion type ICP inserts the coil into the inside, so that a dielectric window is not required, and it can be mounted directly inside the stainless chamber, which is advantageous in size. In addition, it has the great advantage that higher ionization rate and ion density can be obtained than any existing processes.

Meanwhile, the existing internally inserted inductively coupled plasma sputtering apparatus as disclosed in US Patent 6,077,402 (Central Coil design for ionized metal plasma deposition) has been developed mainly for semiconductor production. Such a semiconductor manufacturing apparatus has a circular target placed at the top of the chamber, a wafer substrate placed at the bottom thereof, and an RFI coil inserted therebetween. Such a structure is easy for thin film deposition on semiconductor wafers having circular and flat plate shapes, but has a disadvantage in that it is difficult to apply to base materials requiring vacuum thin film deposition such as tools or decorative articles having a three-dimensional shape. In addition, it has a structure that is produced one sheet at a time has a difficulty in coating a large amount at a time.

Sputtering equipment used for abrasion resistant and decorative coatings has been developed to meet the industrial and economic needs to handle relatively small substrates and large quantities at once. The structure of the industrial sputtering apparatus mainly has a structure in which a plurality of sputter targets are positioned on the side, a substrate system rotated by a gear in the center, and a plurality of coating materials are suspended and deposited on the substrate.

On the other hand, the research for improving the cutting ability and life of the cutting tool by applying a hard film on the surface of the base material has been performed for a long time, and various manufacturing techniques have been developed with various kinds of hard film materials.

The application of such surface coating technology is very broad and expanding from electronics and optics to mechanical and chemical fields. Among them, the most researched field in the field of mechanical applications, and the field of commercialization is active in the field of wear-resistant hard coating for improving the life and wear resistance of cutting tools, molds, dies and the like.

In particular, the technology of coating ceramic materials to extend the life and function of various tools has been actively studied in the world as a strategy to increase the added value through advanced tools. Methods for producing a wear resistant hard coating include chemical vapor deposition such as thermal chemical vapor deposition, plasma chemical vapor deposition, and organic chemical vapor deposition, and physical vapor deposition such as sputtering, arc evaporation, and electron beam evaporation.

In addition, the wear-resistant hard coating material is a combination of Ti (combination of TiN, TiC, ZrN, HfN, CrN, etc. of nitrides, carbides and borides of transition metals (Ti, Zr, Hf) Tertiary nitrides such as C, N), (Ti, Al) N, (Ti, V) N, (Ti, Zr) N, borides, carbides, and (Ti, Al, Zr) N, Ti (C, B, N), etc., quaternary wear resistant hard coatings are also being studied. Among them, TiN is widely used as a wear-resistant hard coating because of its high hardness, excellent adhesion, chemical stability, and good electrical conductivity. It is also widely applied as a decorative coating because of its beautiful golden color.

Meanwhile, TiN, which is most used among wear-resistant hard coatings, has a hardness of about 2000 HK (kgfmm ⁻² ). In the case of TiN manufactured by a general magnetron sputtering method or another deposition method, the hardness is almost 2000-4000kgfmm ⁻² . Various studies have been attempted to further increase the hardness of TiN, but there have been no reports of single TiN thin films with hardness values of more than 4000HK (kgfmm ^-2 ).

Accordingly, the present invention has been made in view of the problems of the prior art, the object of which is to form a film having a high hardness thin film properties to improve the durability of the coating and the ionization rate for plasma formation to increase the productivity according to the coating To provide a multi-coil inductively coupled plasma magnetron sputtering system and a method thereof.

1 is a configuration diagram for explaining the configuration of a first embodiment of an inductively coupled plasma magnetron sputtering apparatus according to the present invention;

Figure 2 is a block diagram for explaining the configuration of a second embodiment of the inductively coupled plasma magnetron sputtering apparatus according to the present invention.

3 is a graph showing the hardness change of the TiN thin film prepared according to the present invention.

Figure 4 is a graph showing the adhesion evaluation results of the TiN thin film prepared according to the present invention.

5 is a graph showing a comparison result of the wear resistance characteristics of TiN thin films prepared by the present invention and other conventional methods.

Explanation of symbols on the main parts of the drawings

10 chamber 12 jig

14a to 14f: target 16a: gas supply valve

16b: vacuum valves 20a to 20f: DC magnetron

25a to 25d: RF power supply 27a to 27f: DC power supply

30a, 30b: RFI coil 35: substrate and substrate holder

40: plasma

In order to achieve the above object, the present invention includes a chamber for providing a plasma generating region; A jig, on which a substrate on which ions and neutral atoms of the deposition material generated by the plasma are deposited is mounted, and which is installed in the center of the chamber; A plurality of targets installed around the jig in the chamber and serving as a source of the plasma; A plurality of sputtering apparatuses for sputtering the target into a plasma state; A plurality of coils provided between the jig and the plurality of targets to convert the plasma generated by the sputtering apparatus into multiple and secondary plasmas; An RF power supply unit supplying RF power to the plurality of coils; It provides a multiple coil type inductively coupled plasma magnetron sputtering system, characterized in that it comprises a plurality of DC power supply for supplying DC power to the plurality of targets, respectively.

The plurality of coils, the plurality of sputtering devices, and the plurality of targets are installed at positions opposite to each other with respect to the jig, and the plurality of coils, the plurality of sputtering devices, and the plurality of targets at regular angle intervals around the jig. Three or more are installed.

The apparatus further includes a plurality of impedance matching units for matching impedances between the plurality of coils and the plurality of RF power supplies, respectively, wherein the chamber is provided with at least one valve for gas supply and vacuum control required for plasma formation. . The plurality of coils are made of a tubular structure with a conductive material, and further include a cooling system for supplying and cooling a cooling medium inside the coil to prevent the plurality of coils from being overheated during the plasma formation process.

The jig is a rotary jig rotatable, and the RF power supplied to the plurality of coils is sequentially supplied with the same phase difference. The target consists of at least one selected from oxides, carbides, and nitrides of transitional metal materials.

In addition, the present invention provides a coating method using plasma, comprising the steps of: electrically grounding a chamber forming a plasma generating region; And a substrate installed in the chamber and coated with the plasma is processed by any one of a method of electrically grounding and applying a negative bias voltage. Generating multiple plasmas by sputtering a plurality of targets that are plasma generation sources installed around the substrate; And converting plasma generated at the target into multiple and secondary plasmas using a plurality of RF inductive coupling coils installed at positions between the substrate and the target, and coating the substrate on the substrate. A coating method using a coil-type inductively coupled plasma magnetron sputtering system is also provided.

The method further includes a pretreatment process for improving adhesion of the coating layer by removing impurities and residual gas present in the substrate using the plasma before the coating, wherein the pretreatment process is performed by generating an inductively coupled plasma using argon gas. The target consists of at least one selected from oxides, carbides, and nitrides of transitional metal materials.

The present invention is to install a plurality of inductively coupled plasma generating device (coil) in the existing large-capacity sputtering apparatus to deposit a high hardness wear-resistant coating and decorative coating, the present invention is manufactured by a variety of conventional wear-resistant coating deposition method The high hardness wear resistant coating having a very high hardness compared to the prepared thin film could be prepared by inductively coupled plasma sputtering. In addition, it succeeded in synthesizing the TiN thin film having excellent characteristics at low temperature, and it is possible to coat on a plastic substrate and the temperature-restricted substrate.

(Example)

Hereinafter, with reference to the accompanying drawings showing a preferred embodiment of the present invention described above in more detail.

1 is a block diagram for explaining the configuration of the first embodiment of the inductively coupled plasma magnetron sputtering apparatus according to the present invention, Figure 2 is a configuration of a second embodiment of the inductively coupled plasma magnetron sputtering apparatus according to the present invention 3 is a graph showing the change in hardness of the TiN thin film prepared according to the present invention, Figure 4 is a graph showing the results of evaluation of the adhesion of the TiN thin film prepared according to the present invention, Figure 5 is the present invention and the existing A graph showing a comparison result of wear resistance of TiN thin films prepared by other methods.

The apparatus used in the present invention is a DC magnetron mounted on both sides of the substrate 20 mounted on the rotary jig 12 installed in the center of the chamber 10 to sputter the targets 14a and 14b as shown in FIG. 1. 20a and 20b, two inductively coupled plasma generators, that is, radio frequency inductively coupled (RFI) coils 30a and 30b are mounted on the DC magnetrons 20a and 20b.

The sputtering method is a method of sputtering targets 14a and 14b located on the side surface. The substrate 35 is positioned in the rotary jig 12 in the middle, and the RFI coil is positioned between the target 14a and the substrate 35. 30a and 30b are provided to further activate the plasma.

In the embodiment of the present invention, the jig 35 is described as a rotary jig rotating with respect to the RFI coils 30a and 30b as an example. However, in some cases, the jig is fixed and the plurality of RFI coils 30a and 30b are fixed. By sequentially supplying the RF power supplied to have the same phase difference, the plasma may be rotated about the substrate 35 so as to have the same effect as the rotary jig.

This is because the plasma is applied to the substrate 35 in a manner such that a rotary jig is used to contact the plasma in an even distribution on the surface of the substrate 35 in the plasma region 40 formed by the RFI coils 30a and 30b. This means that by rotating around the same effect can be achieved.

Further, if the structure of the present invention is further extended, it may have a structure as shown in FIG. DC magnetrons 20c to 20f, which are sputtering apparatuses, and four targets 14c to 14f, respectively, are mounted on both sides of the chamber 10, and the RF power supply units 25c to 25f and the DC power supply units 27c to 27f are thus mounted. When connected, the deposition rate and the uniformity of the deposition film can be improved, and in some cases, as shown in FIGS. 1 and 2, not only two or four installations can be installed, but more than that, plasma can be generated to generate deposition. have.

In the present invention, two sputtering targets 14a and 14b and two RFI coils 30a and 30b were used to deposit TiN thin films widely used as wear-resistant coatings and decorative coatings.

Ti targets (purity = 99.9%, diameter = 2 inches) were deposited in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ) having a purity of 99.999%, and the jig 12, the substrate 35, and the chamber 10. Is electrically grounded.

The distance between the targets 14a and 14b and the substrate 35 is approximately 10 cm, and the distance between the targets 14a and 14b and the RFI coils 30a and 30b is about 3 cm, and the left and right lengths of the RFI coils 30a and 30b are About 4 cm, the distance between the RFI coils 30a and 30b and the substrate 35 has an arrangement of about 3 cm.

On the other hand, DC power was supplied to the targets 14a and 14b through the DC power supply units 27a and 27b. The inductively coupled plasma 40 is formed between the sputtering targets 14a and 14b and the substrate 35. The high frequency voltage of 13.56 MHz is applied to the RFI coil 30a through the impedance control box using the RF power supply units 25a and 25b. , 30b).

The RFI coils 30a and 30b are wound into a copper tube twice and inserted into the chamber 10. The RFI coils 30a and 30b are supplied with cooling water to cool the inside of the RFI coils 30a and 30b during deposition and have a diameter of about 15 cm. In order to minimize the influence of the residual gas, the pressure in the chamber 10 was set to 1 × 10 ⁻⁶ Torr or less, and then argon and a reactant gas were supplied.

Table 1 shows the color distribution of the sample on which the decorative TiN thin film was deposited on the plastic substrate 35. All TiN thin films were deposited at 70 ° C or lower. The deposition conditions of the decorative TiN thin film using the present invention are as follows.

At a process pressure of 20 mTorr, 10 sccm of argon gas and 2 sccm of nitrogen gas were flowed. 200W DC power was applied to the Ti target, and 2 inch Ti targets 14a and 14b were used, so the power density applied to the targets 14a and 14b was 9.86W / cm ² . 300W RF power was applied to the RFI coils 30a and 30b, respectively.

To compare the properties of the deposited TiN thin film, the color distribution of the TiN thin film deposited by the asymmetric magnetron sputtering method on the same plastic sample is also shown.

In this case, a 10 cm diameter Ti target was used, and the applied power was 2.5 kW, so the power density applied to the target was 31.83 W / cm ² . As shown in Table 1, the TiN thin film manufactured in the present invention and the asymmetric magnetron sputtering apparatus shows almost similar characteristics. But the most important difference is the power applied to the Ti target. Asymmetric magnetron sputtering successfully deposited TiN thin films only above 30 W / cm ² , but decorative TiN thin films were not deposited at lower power densities.

However, in the present invention, even at 10 W / cm ² decorative TiN thin film was easily formed. Also, the wear resistance of the deposited TiN thin film was also superior to that of the TiN thin film prepared by the asymmetric magnetron sputtering method.

The plasma pretreatment of the substrate 35 is a pretreatment process performed to improve adhesion between the substrate 35 and the thin film to be deposited by generating plasma to remove impurities or residual gas present in the substrate 35.

In the conventional general sputtering deposition method, a high negative voltage is applied to the substrate (about -1000V) to perform plasma pretreatment of the substrate, whereas the present invention has developed a new plasma pretreatment process using an inductively coupled plasma.

Only the argon gas was flowed in the chamber 10 to maintain the pressure at 20 mTorr, and then plasma pretreatment of the substrate 35 was performed while generating an inductively coupled plasma by applying RF power to the RFI coils 30 and 30b. . At this time, the applied RF power was 200W, the pretreatment time was performed for about 5 minutes.

It was confirmed that the adhesion between the thin film and the substrate 35 was greatly increased by the plasma pretreatment of the substrate 35. In particular, when the substrate 35 is ABS plastic, it is difficult to raise the temperature of the substrate 35 to about 100 ° C or more. The wear-resistant and decorative coating on the substrate 35 may be referred to as a low temperature deposition process. In this low temperature deposition process, plasma pretreatment of the substrate 35 using the RFI coils 30a and 30b showed a great effect.

In the case of the specimen without pretreatment, the TiN thin film was peeled off after deposition. In the case of the pretreatment using inductively coupled plasma, the thin film was deposited very cleanly.

Accordingly, the plasma pretreatment of the substrate 35 by generating the inductively coupled plasma using the RFI coils 30a and 30b is more effective in the low temperature deposition process such as plastic, in which the substrate 35 is limited by temperature. It can be said to be large.

When the plasma is generated by inserting two or more RFI coils 30a and 30b, the biggest problem is that the plasma is not generated due to the interference between RF or becomes unstable during the process. However, in the present invention, the interference phenomenon between the two RF plasmas is controlled by the impedance matching method, so that RF matching is well maintained even at high power without major problems.

Each characteristic of the substrate deposited according to the present invention is as follows.

1. Hardness of thin film

3 illustrates the hardness change of the TiN film according to the high frequency power (ICP power) applied to the RFI coils 30a and 30b. The hardness of TiN increases with increasing ICP power, and the hardness rapidly increases from 2500HK _0.01 to 6000HK _0.01 between 200W and 300W. In addition, at higher ICP power, the hardness was above 6500HK _0.01 .

The modulus of elasticity also increased with increasing ICP power, and increased rapidly at 200W and 400W. Hardness above 6500HK _0.01 is very high compared to the hardness of TiN reported in the literature. In general, TiN deposited by magnetron sputtering or another method has a hardness of 2000 to 4000 kgfmm ⁻² .

2. Adhesive force of thin film

The adhesion evaluation of the thin film was made by the indentation test method and the scratch test method using Rockwell-C indenter. 4 shows the sound waves in the scratch test method with respect to the load. The critical load of the TiN film observed by the acoustic wave in the scratch test method was 30N or more, which is known to be industrially applicable, and this was confirmed by observing the scratch channel. As a result of observing the indentation, crack propagation around the indentation or film dropping could not be observed.

3. Wear resistance of thin film

5 shows the wear resistance characteristics of the TiN thin film manufactured by the present invention and the TiN thin film manufactured by other methods. TiN irradiated was TiN (ICP TiN, 6500HK _0.01 ) manufactured with ICP power at 400W, TiN (DC TiN, 4400HK _0.01 ) manufactured using general DC magnetron sputtering, and TiN (PECVD manufactured by PECVD method, respectively). TiN, 3500HK _0.01 ). As a wear test, a ball-disk (ball on disk type) device of CSEM Corporation was used.

S440C balls (hardness 590HK) having a diameter of 6 mm were used as counterparts, and wear was caused while rotating the specimen on which the thin film was deposited. The specimen was rotated 8000 times with a rotational speed of 0.14 m / s and an applied load of 5N.

5 shows the wear amount of the TiN thin film and the wear amount of the steel ball as a counterpart after the abrasion resistance test, respectively. In the case of ICP TiN, the thin film was hardly worn and the wear amount of the ball was the largest. The amount of wear depends on the hardness and adhesion. The PECVD TiN thin film with the relatively low hardness has the largest wear and the smallest wear on the counterpart. ICP TiN thin films showed better wear resistance even on TiN thin film beams produced by other methods due to their high hardness and excellent adhesion.

According to the present invention made as described above, TiN, which is widely used as a wear-resistant hard coating, was manufactured by using a sputtering apparatus equipped with an inductively coupled plasma, and TiN wear resistance of a new tissue having a hardness about 3 times higher than that of conventional TiN was obtained. Hard coatings can be prepared. Deposition of such ultra-hard wear coatings on tools, molds, dies, etc., significantly extends the life of the product.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments and the general knowledge in the technical field to which the present invention pertains without departing from the spirit of the present invention. Various changes and modifications will be made by those who possess.

Claims (14)

A chamber providing a plasma generating region; A jig, on which a substrate on which ions and neutral atoms of the deposition material generated by the plasma are deposited is mounted, and which is installed in the center of the chamber; A plurality of targets installed around the jig in the chamber and serving as a source of the plasma; A plurality of sputtering apparatuses for sputtering the target into a plasma state; A plurality of coils provided between the jig and the plurality of targets to convert the plasma generated by the sputtering apparatus into multiple and secondary plasmas; An RF power supply unit supplying RF power to the plurality of coils; And a plurality of DC power supply units supplying DC power to the plurality of targets, respectively. The multiple coil type inductively coupled plasma magnetron sputtering system according to claim 1, wherein the plurality of coils, the plurality of sputtering apparatuses, and the plurality of targets are installed at opposite positions with respect to the jig. The multiple coil type inductively coupled plasma magnetron sputtering system according to claim 1, wherein the plurality of coils, the plurality of sputtering devices, and the plurality of targets are installed at regular intervals about the jig. The multi-coil inductively coupled plasma magnetron sputtering system of claim 1, further comprising a plurality of impedance matching units respectively matching impedances between the plurality of coils and the plurality of RF power supplies. The multi-coil inductively coupled plasma magnetron sputtering system of claim 1, wherein the chamber comprises at least one valve for gas supply and vacuum degree control required for plasma formation. The multi-coil inductively coupled plasma magnetron sputtering system according to claim 1, wherein the plurality of coils are coils having a tube structure as a conductive material. The multi-coil inductively coupled plasma magnetron of claim 6, further comprising a cooling system for supplying and cooling a cooling medium in the coil to prevent the plurality of coils from overheating during the plasma formation process. Sputtering system. The multi-coil inductively coupled plasma magnetron sputtering system of claim 1, wherein the jig is a rotatable jig. The multiple coil type inductively coupled plasma magnetron sputtering system according to claim 1, wherein the RF power supplied to the plurality of coils is sequentially supplied with the same phase difference. The multi-coil inductively coupled plasma magnetron sputtering system of claim 1, wherein the target is at least one selected from an oxide, a carbide, and a nitride of a transition metal material. In the coating method using a plasma, Electrically grounding the chamber forming the plasma generating region; And processing the substrate installed in the chamber and coated with the plasma by any one of a method of electrically grounding and a method of applying a negative bias voltage; Generating multiple plasmas by sputtering a plurality of targets that are plasma generation sources installed around the substrate; And Using multiple RF inductive coupling coils installed at a location between the substrate and the target to plasma multiple times and secondarily to coat the substrate on the substrate. Coating method using inductively coupled plasma magnetron sputtering system. 12. The multi-coil inductively coupled plasma magnetron sputtering of claim 11, further comprising a pretreatment process for improving adhesion of the coating layer by removing impurities and residual gas present in the substrate before the coating. Coating method using the system. The method of claim 12, wherein the pretreatment process is performed by generating an inductively coupled plasma using argon gas to process the inductively coupled plasma magnetron sputtering system. 12. The method of claim 11, wherein the target is at least one selected from oxides, carbides, and nitrides of a transitional metal material.