JP2608137B2 - Evaporator for ion plating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to an ion plating apparatus, and more particularly, to performing ion plating by a so-called HCD (Hollow Cathode Discharge) method, the uniformity and adhesion of a deposited film are improved. Particularly, the present invention relates to an ion plating evaporator for enabling excellent film formation with high deposition efficiency.

(Prior art) The ion plating method using the HCD method has a very high ionization rate, so the quality of the deposited film is better than that of the normal ion plating using EB (electron beam), and the adhesion to the substrate is excellent. Furthermore, the HCD method has a great advantage in that even if the conditions such as the reaction gas flow rate, the degree of vacuum, the bias voltage, the substrate temperature, and the pretreatment of the substrate are slightly changed, an easy and smooth adaptation can be observed. And is known.

That is, ion plating by the HCD method is described in Metal Surface Technology 35 [1] P. 16 to 24 (1984) and Powder and Powder Metallurgy 32 (1985) P. 55 to 60.

(Problems to be Solved by the Invention) Currently used hollow cathodes for plasma generation,
The HCD gun is made of Ta and has a durable life of about 100 to 150 hours per piece. It cannot be used for coating beyond this and is very expensive (40,100,000 yen per piece)
Since this accounts for about 30 to 50% of the coating cost, the development of an inexpensive HCD gun that can be used stably for a long time is desired.

In the current ion plating method by the HCD method, an H-shaped HCD gun of an inverted L-shape is mainly used for facilitating dissolution of an evaporating substance such as Ti so as to facilitate the first HCD beam start. . This not only has the disadvantage that, for example, when a ceramic coating of TiN is performed on the substrate, the coating film becomes thinner just above the HCD gun. There was also a disadvantage that it became thinner.

Recently, the inventors have developed a graphite HCD gun to replace the conventional Ta HCD gun in order to reduce the cost of the HCD gun. However, although this graphite HCD gun has the advantage that the manufacturing cost is 1/20 to 1/100 as compared with that of the conventional Ta, the discharge characteristics required for the HCD gun, especially, it can be used stably for a long time. It turns out that it is not always optimal for the demands of obtaining.

Therefore, the outer layer is made of graphite, and the inner layer is made of Ta, W or La.
The filtrate that was studied concentric bilayer HCD gun using B _6, a despite the inexpensive discharge characteristics good, yet can be stably used for a long time, be innovative and it can be said as HCD gun understood. However, such a double-layer HCD gun has an excessively large outer diameter, which considerably promotes the tendency of a thin coating film on a substrate portion corresponding to directly above the HCD gun. With the use of, a non-uniform heat transfer to the substrate due to the red heat of the gun occurred immediately above the HCD gun, and the solution had to be solved.

In addition, the deposition rate in a conventional ion plating apparatus with a conventional HCD gun capacity of about 300 A or 500 A is, for example, about 0.05 to 0.5 μm / min with Ti coating,
At this time, the ionization rate was at most about 30 to 40%, but in recent years, in order to increase the deposition rate to about several μm / min, the development of an evaporation HCD gun with a large capacity of about 1000 A has been advanced. When the capacity of the HCD gun is increased, the ionization rate becomes 5
There is also an advantage that the film quality due to ion plating is significantly improved by being 0% or more.

However, when such a large-capacity HCD gun is used, not only the cost increase of the cathode gun mentioned above, but also the unevenness of the coating film due to the increase in the diameter of the HCD gun and the uneven heat of the substrate. The problem of delamination of the deposited film due to the above is very important. That is, it is required to increase the deposition efficiency and maintain a good plasma atmosphere when using a large-capacity HCD gun.

Therefore, the above-mentioned various disadvantages are eliminated, and a large amount of vapor deposition is performed using a large capacity HCD gun of about 1000 A or more. It is an object of the present invention to provide an evaporator for ion plating.

(Means for Solving the Problems) The above object is advantageously satisfied by a configuration having the following items as the gist.

That is, the present invention provides an HCD ion plating method in which a plurality of crucibles accommodating an evaporation source, a plurality of hollow cathodes for plasma generation corresponding to the crucibles, a substrate, and a reaction gas inlet are arranged in a vacuum chamber. in the device, surround the crucible and established the first focusing coil surrounding the vapor transfer pathway from the crucible to the nearest of the substrate, at least one hollow cathode, selected from among the group consisting of Ta, W and LaB ₆ An inner layer, a graphite outer layer covering the outer periphery of the inner layer, and a second focusing coil surrounding the outer periphery of the outer layer with a diameter of 1/2 or less of the diameter of the first focusing coil. None, Magnet that sets the direction of plasma beam emission laterally or obliquely downward with respect to the surface of the evaporation source in the crucible, and generates magnetic field lines parallel to the deposition surface of the substrate Alternatively, it is an ion plating evaporator in which a coil is provided at a position facing a crucible sandwiching a substrate.

Further, the present invention provides the above apparatus, wherein
a, the inner layer consisting of at least one selected from among the group consisting of W and LaB ₆ and covers the outer periphery of the inner layer, taken less than half of the diameter of the first focusing coil diameter surrounding the vapor transfer pathways This is an apparatus comprising a ceramic layer in which a surrounding second focusing coil is embedded.

Further, in practice, the second focusing coil surrounding the outer periphery of the outer layer of the hollow cathode is coated with ceramics, and further the cylindrical ceramics embedded with the second focusing coil is
Advantageously, it is fixed integrally with the outer layer at a constant gap.

(Operation) FIG. 1 schematically shows a batch-type HCD method ion plating apparatus using the ion plating evaporator of the present invention, wherein 1 is a substrate and 2,2 'is a reaction gas introduction. Port, 3,3 'is a crucible, 4,4' is an evaporation source (for example, Ti), 5,5 'is an exhaust port for high vacuum evacuation, 6 is a vacuum tank,
7,7 'is the HCD gun, 8,8' is the first focusing coil surrounding the vapor transfer path from crucible 3,3 'to Substrate 1, 9,
9 'is a plasma beam.

The HCD gun 7,7 'is an outer layer of graphite 7-1,7'-1
And the inner layers 7-2 and 7'-2 of Ta in this example. Although illustration is omitted to prevent discharge, the inner layer 7
-2 or 7'-2 and the evaporation source 4 or 4 'in the crucible can be energized. As a result, abnormal discharge of the HCD gun is reduced, and the life of the gun is extended.

The HCD gun 7 can maintain a stable supply of the plasma beam for a long time by always keeping the distance to the crucible 3 or 3 'constant by the feed mechanism 7-3 or 7'-3.
In the figure, 7-4, 7'-4 is the power supply of the HCD gun, and 7-5, 7'-
Reference numeral 5 denotes an Ar gas supply port. Further, 10 or 10 'is a second focusing coil around the outer layer 7-1 or 7'-1. The second focusing coils 10, 10 'focus the generated plasma into narrow plasma beams 9, 9', wherein the diameter of the second focusing coils 10, 10 'is the first focusing coil of the vapor movement path. It is important to make the diameter less than 1/2 of 8,8 'and to make the influence of the oblique magnetic field smaller than the magnetic field on the steam transfer path. This is based on the following findings.

That is, according to the experiments by the inventors, if a large-capacity HCD gun is used and a coil for focusing the plasma beam is provided in the hollow cathode, a large amount of the evaporation source can be dissolved and the amount of evaporation can be increased. It was found that the appropriate amount of adhesion to the substrate could not be obtained, and that the cause was that the magnetic field due to the focusing coil around the hollow cathode disturbed the magnetic field due to the focusing coil surrounding the vapor flow toward the substrate did. Then, when the conditions for focusing the plasma beam without disturbing the steam flow were sought, it was found that the diameter of the focusing coil on the outer periphery of the hollow cathode should be limited to not more than 1/2 of the diameter of the focusing coil in the steam movement path.

Next, the plasma beams 9, 9 'focused into narrow beams are acted on by magnetic fields from top to bottom by first focusing coils 8, 8' around the crucibles 3, 3 ', as shown by the dotted lines in the figure. To be irradiated toward the melt. The plasma beam irradiated in this manner causes the evaporation source to evaporate right above, thereby enabling uniform deposition on the substrate.

Further, a coil (or magnet) 11 for generating magnetic lines of force parallel to the deposition surface is provided on the non-deposition surface side of the substrate 1 to uniformly adhere the evaporant.

The inner layer 7-2 (or 7'-2) of the HCD gun 7
The configuration shown in FIG. 2 may be used.

That is, the inner layer of the HCD gun 7 shown in FIG. 1 is formed by welding a head 14 made of a thin tube made of W to a base 13 made of a thick tube made of Ta and fixed to a chuck 12 by welding or the like. And a fin 15 made of Ta and extending coaxially with the head 14 with a ten-shaped cross section inside the head 14.
It is welded to the inner wall surface of 14. Reference numeral 16 denotes a welded portion, 17 denotes an opening, and 18 denotes a gas inlet such as Ar.

The HCD gun having the above-described configuration has a head 14 made of W in a region where plasma is mainly generated, that is, a high temperature region, and a base 13 made of Ta in a region where plasma is less generated, that is, a low temperature region.
It is characterized by having arranged.

Also, as shown in FIGS. 3 (a) and (b), a second focusing coil 10 around the outer layer 7-1 (or 7'-1).
(10 ') is covered with ceramics 19 to form an insulating coil,
It is preferable to prevent discharge between the outer layer 7-1 and the second focusing coil 10. In this case, the outer layer 7-1 is made of ceramics.
The outer layer 7-1 may be omitted because 19 protects the cathode 7-2 against attacks from the outer vapor stream.
At this time, if the second focusing coil 10 is embedded in the cylindrical ceramic 19 and the ceramic 19 is fixed integrally with the outer layer 7-1, the gap between the ceramic 19 and the outer layer 7-1 can be kept constant. It can be used for a long time.
FIG. 3C shows an example in which the hollow cathode is a rectangular parallelepiped.

Although a batch type ion plating apparatus is shown as an application example of the apparatus of the present invention, it is also effective in a large continuous type ion plating apparatus, and in this case, a substrate, that is, a steel plate to be ion-plated,
On the entry side to the ion plating area, the air passes through the differential pressure chamber row with the degree of vacuum increased sequentially, and on the exit side, passes through the differential pressure chamber row with the reduced vacuum degree sequentially. to
-Air) method, that is, a differential pressure sealing method that induces continuous passage of a long material while maintaining the pressure difference between the differential pressure chambers.

(Example) C0.041wt% (hereinafter simply referred to as%), Si 3.31%, Mn0.07
3%, Mo 0.011%, Se 0.021%, Sb 0.025%, the balance being virtually Fe-composed silicon steel slab is hot-rolled to a thickness of 2.0mm and then subjected to intermediate annealing at 950 ° C. The resultant was subjected to cold rolling twice to obtain a final cold-rolled sheet having a thickness of 0.20 mm.

After performing decarburization and primary recrystallization annealing in wet hydrogen at 820 ° C, MgO (35%) and Al ₂ O ₃ (60%)
After applying an annealing separating agent containing TiO ₂ (3%) and MgSO ₄ (2%) as main components, applying a secondary crystal annealing at 850 ° C. for 50 hours, then purifying at 1200 ° C. in dry H ₂ for 5 hours. Was done.

Next, the oxide on the steel sheet surface was removed by pickling, and then a mirror surface state with a center line average roughness of 0.05 μm was obtained by electrolytic polishing.

Thereafter, a TiN film was formed to a thickness of 1 μm using the ion plating apparatus of the present invention shown in FIG.

The plasma generation conditions at this time were as follows: acceleration voltage 70 V, current 100
Assuming that 0A, the excitation conditions of the second focusing coils 10, 10 'around the HCD gun, the first focusing coils 8, 8' around the crucible, and the coil 11 on the substrate non-deposition surface side are as shown in Table 1. And The bias voltage at this time is
50V, substrate temperature is 400 ° C. Table 1 shows the magnetic properties and adhesion of the products thus obtained.

As is evident from Table 1, under the conditions according to the present invention, both the uniformity and the adhesion of the coating film are remarkably excellent.

(Effects of the Invention) According to the present invention, it is possible to form a large amount of vapor-deposited film having good uniformity and excellent adhesion by HCD ion plating under high efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic view of an ion plating apparatus of the present invention, FIG. 2 is a cross-sectional view of a hollow cathode, FIG. 3 (a) is a cross-sectional view of a hollow cathode, and FIGS. FIG. 1 Substrate, 3 Crucible 4 Evaporation source, 6 Vacuum tank 7,7 'HCD gun 7-1,7'-1 Outside layer 7-2,7'-2 ... Inner layer 7-3,7'-3 ... Feed mechanism 7-4,7'-4 ... HCD gun power supply 7-5,7'-5 ... Ar gas supply port 8,8 '... First focusing coil 9,9 '... plasma beam 10,10' ... second focusing coil, 11 ... coil 12 ... chuck, 13 ... base 14 ... head, 15 ... fin 16 ... ... Welds, 17 ... Openings 18 ... Gas inlets, 19 ... Ceramics

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuhiro Suzuki 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Corporation Research and Development Headquarters (56) References JP-A-64-65260 (JP, A) 1-168860 (JP, A)

Claims (4)

(57) [Claims] An HCD ion plating method in which a plurality of crucibles accommodating an evaporation source, a plurality of hollow cathodes for generating plasma corresponding to the crucibles, a substrate, and a reaction gas inlet are arranged in a vacuum chamber. in the device, surround the crucible and established the first focusing coil surrounding the vapor transfer pathway from the crucible to the nearest of the substrate, at least one hollow cathode, selected from among the group consisting of Ta, W and LaB ₆ The inner layer consisting of, the outer layer of graphite covering the outer layer of the inner layer and the outer layer of the outer layer,
A second encircling with a diameter of 1/2 or less of the diameter of the first focusing coil;
And a magnet or a coil that generates a magnetic field line parallel to the deposition surface of the substrate, and sets the direction in which the plasma beam is emitted horizontally or obliquely downward with respect to the surface of the evaporation source in the crucible. An ion plating evaporator provided at a position facing a crucible sandwiching a straight. 2. The ion plating evaporator according to claim 1, wherein the second focusing coil surrounding the outer periphery of the outer layer of the hollow cathode is coated with ceramics. 3. The evaporator for ion plating according to claim 2, wherein the cylindrical ceramic in which the second focusing coil is embedded is fixed integrally with the outer layer at a predetermined gap. 4. The vapor deposition apparatus for ion plating according to claim 1, wherein the hollow cathode covers an inner layer made of at least one selected from the group consisting of Ta, W and LaB ₆ and an outer periphery of the inner layer. And an evaporator for ion plating, comprising a ceramic layer in which a second focusing coil surrounding the vapor transfer path and having a diameter of 1/2 or less of the diameter of the first focusing coil is embedded.