JPH0730446B2 - Membrane coating method for fine objects - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for coating a film on a fine article such as a microdrill, a punch, a microcutter, a pin and a needle.

[Conventional technology]

For general tools other than the above-mentioned small items, improved machinability,
PVD method (physical vapor deposition method) such as vacuum deposition, sputtering, ion plating, combined use of vacuum deposition and ion irradiation to improve wear resistance and corrosion resistance, for example, TiN, TiC, AlN, ZrN Conventionally, a method of coating a high hardness film such as the above has been adopted.

In that case, the heating to be coated, i.e. the tools in this example, is usually used together. This is to clean the tools before coating by heating to improve the adhesion of the film to be coated, or to control the temperature of the tools to improve the adhesion and quality of the film. is there.

In order to enable efficient heating in a vacuum, heating of such tools is usually performed by radiant heaters arranged around the tools and mainly by radiant heat from the heaters.

For measuring the temperature of tools during heating, a pyrometer for measuring infrared radiation from an object or a thermocouple for measuring temperature by attaching to the object is usually used.

[Problems to be solved by the invention]

However, conventionally, the coating of a film on a fine material such as a microdrill (here, a diameter of the drill is about several mmφ or less) has not been performed on an industrial scale as much as for other tools. . It is considered that the reason is that the conventional method cannot obtain the effect of coating on the fine article as remarkably as that on other tools.

There are roughly two possible causes for this.

One is that when the radiant heating method as described above is used for heating a fine object, a particularly thin tip portion such as a cutting edge portion is concentrated and excessively heated.

This is because, in the conventional method, radiant heat is supplied to the entire small object, so that the heat input to the tip having a large surface area relative to the volume becomes excessive.

Another reason is that it is difficult to control the temperature because it is extremely difficult to measure the temperature of the tip of a small object.

This is because a pyrometer requires a certain amount of field of view, but a small object cannot obtain it, and a thermocouple has a size restriction that cannot be attached to a small object. .

Taking a microdrill as an example, for example, it is required to coat a thin blade edge portion with a film uniformly, and for that purpose, heating temperature is uniform and precise temperature control is required. The material of the microdrill is, for example, tungsten carbide (WC). If the heating temperature is too low, the adhesion of the film will be poor, and if it is too high, decarburization will occur and it will become brittle. Also, in the case of a circuit board for drilling holes, the work material is a composite material with high hardness and high adhesiveness such as FRP, so it is necessary to precisely adjust the film quality for such things. Temperature control is required.

Therefore, the present invention provides a film coating method which prevents excessive heating of the tip of the fine object when coating the film and facilitates temperature measurement of the tip. The purpose is to

[Means for solving problems]

The film coating method of the present invention, when coating a film on a fine product by the PVD method, attaches the fine product to a jig with its handle and heats the jig to heat the fine product by heat conduction from the jig. In addition, the temperature of the jig is measured.

[Action]

When the small object is attached to the jig with the handle and the jig is heated, the handle of the fine object is heated by heat conduction from the jig and the tip is heated by heat conduction from the handle. Therefore, the heat input to the tip of the small object does not become excessive, and excessive heating of the tip is prevented.

Further, the temperature of the jig can be easily measured with a pyrometer, a thermocouple, or the like, and the temperature of the jig and the temperature of the tip of the small object are almost uniquely determined. By measuring the temperature, it is possible to easily measure the temperature of the tip of the fine article without causing a large error.

〔Example〕

FIG. 1 is a schematic sectional view showing an example of an apparatus for carrying out the method according to the present invention.

A cylindrical jig 10a is housed in a vacuum container 2 that is evacuated by a vacuum evacuation device 4. This jig 10a
Is attached in the middle of a rotary shaft 8 penetrating the vacuum container 2 through the upper and lower vacuum seal portions 6, 6, and the rotary shaft 8 and the jig 10a are provided outside the vacuum container 2 by a rotary drive device 26.
Is rotated by, for example, an arrow A.

On the outer peripheral surface side of the jig 10a, a plurality of holes 11 into which a handle portion (shank portion) 13 of a fine object 12 such as a microdrill for covering a film can be inserted and held. By the way, the thickness of this jig 10a is
It is thicker than the length (for example, about 25 mm).

A plurality of heaters 14a are housed on the side opposite to the surface of the jig 10a on which the fine article 12 is attached, that is, inside the jig 10a in this example, and the electric power from the heating power source 20 is supplied in this example. The heater 14a is supplied to heat the heater 14a through the insulating transformer 18 and the brush 16 and through the conductor in the rotary shaft 8.

On the other hand, on the wall surface of the vacuum container 2, a plurality of arc type evaporation sources 28a are attached to the outer peripheral surface of the jig 10a in this example. The evaporation source 28a has a cathode 30 made of a substance to be coated on the fine substance 12, and a voltage of, for example, several tens V to several hundreds V is applied between the cathode 30 and the vacuum container 2 from an arc power source 32. The cathode material 31 can be evaporated by performing a vacuum DC arc discharge between them. In that case, since only the discharge point of the cathode 30 is locally melted, even if the evaporation source 28a is turned sideways as in this example, there is no possibility that the molten material will spill. still,
The trigger for starting the arc discharge and the like are omitted.

In addition, on the wall surface of the vacuum container 2, a pyrometer 34a is used in this example.
Is attached so that the temperature of the outer peripheral surface of the jig 10a is measured.

Further, in this example, the jig 10a, the rotating shaft 8, the heater 14a, etc. are electrically insulated from the ground, and the jig 10a is attached from the bias power source 24 via the brush 22 and the rotating shaft 8 and, by extension, there. A negative bias voltage of, for example, about several hundred V to 1000 V can be applied to the fine object 12. As a result, it is possible to perform discharge cleaning of the small objects 12 and
The film can be coated with a bias voltage applied to the film.

At the time of coating the film, the handle portions 13 of the plurality of fine objects 12 to be coated are inserted into the respective holes 11 of the jig 10a, and the inside of the vacuum container 2 has a predetermined vacuum degree (for example, 10 ^-5 to 10 ^-7 Torr (About) and the heater 10a heats the jig 10a from the inside. Then, each evaporation source 28a is operated, and the cathode material 31 from the evaporation source 28a is vapor-deposited on a desired region such as the tip of each fine article 12 to coat the film. At that time, the jig 10a is rotated in order to improve the uniformity of processing. When coating the compound film, a reaction gas that reacts with the cathode material 31 may be introduced into the vacuum container 2.

In the above case, unlike the conventional case in which each thin object 12 is directly heated by the radiant heat from the heater, the handle portion 13 is heated by the heat conduction from the jig 10a and the heat from the handle portion 13 is increased. The tip is heated by conduction. Therefore, the heat input to the tip of the fine object 12 does not become excessive, and excessive heating of the tip is prevented.

Further, at the time of coating, the temperature of the outer peripheral surface of the jig 10a is measured by the pyrometer 34a. In this case, the pyrometer 34a is used.
Since a sufficient field of view can be secured for a, temperature can be measured easily and accurately. Moreover, the jig 10
There is a substantially unique relationship between the temperature of a and the temperature of the tip of the fine article 12.Therefore, if the relationship is grasped in advance, the temperature of the tip of the fine article 12 can be determined by the pyrometer 34a. It can be measured easily and without any large error. As a result, temperature control of the tip of the small object 12 (temperature control)
Can be done easily and accurately.

As a result, it is possible to satisfactorily coat the film on the fine object 12 such as a microdrill, which has been conventionally difficult.
That is, it is possible to coat the tips of the plurality of fine objects 12 with a film having good adhesion and film quality on an industrial scale.

Further, in this example, since the jig 10a only needs to be heated by the heater 14a, the heater 14a can be incorporated inside or inside the jig 10a, and a reflector unlike the conventional radiant heater is not necessary. Therefore, the space required for mounting the heater can be reduced, and the vacuum container 2 can be downsized.

Further, in this example, the heater 14a is connected to the evaporation source by the jig 10a.
Since the cathode material 31 is less likely to adhere to the heater 14a because it is isolated from the coating atmosphere of 28a, frequent cleaning of the heater 4a is not required.

The heater 14a may be provided with a sliding portion so as not to rotate regardless of the rotation of the jig 10a, which makes it easier to supply power to the heater 14a.

Also, the vacuum seal portion 6, especially the upper vacuum seal portion 6,
In order to protect the internal O-ring and the like from the heat generated by the heater 14a, it may be cooled with cooling water or the like.

Further, the jig 10a may have a structure capable of being divided into a plurality of pieces in the circumferential direction and / or the axial direction in order to facilitate the attachment / detachment of the fine object 12 to / from the jig 10a.

FIG. 2 is a schematic sectional view showing another example of the apparatus for carrying out the method according to the present invention. The difference from the example of FIG. 1 will be mainly described. In this example, a cylindrical jig 10 is provided inside the vacuum container 2.
b is stored and fixed on a base 52 made of an insulating material.
A bias power source 24 is connected between the jig 10b and the vacuum container 2 as in the case of the above example.

A plurality of holes 11 into which the handle portion 13 of the fine article 12 as described above can be inserted and held are formed on the inner peripheral surface side of the jig 10b.

Further, an electron beam evaporation source 28b is provided inside the jig 10b and substantially on the central axis thereof. This evaporation source 28b is
In the crucible 36, an evaporation material 38 made of a substance to be coated on the fine matter 12 is provided, and the evaporation material 38 can be evaporated by irradiating it with an electron beam 42 from an electron gun 40. . Moreover, in order to improve the uniformity of processing for a plurality of fine objects 12, the linear drive device 50
Through the 46, the crucible 36 can be moved up and down as shown by an arrow B. 48 is a vacuum seal for the shaft 46.

On the other hand, a coil-shaped heater 14b is wound around the outer peripheral surface of the jig 10b, and the electric power from the heating power source 20 is supplied to the heater 14b via the insulating transformer 18. 54 is a vacuum seal part for power supply.

Further, in this example, the thermocouple 34b for measuring the temperature is embedded in the jig 10b.

When coating the film, the fine article 12 is attached to the jig 10b by the handle 13 thereof, the jig 10b is heated by the heater 14b, and each fine article 12 is heated by heat conduction from the jig. Also thermocouple 34
b, the temperature of the jig 10b at that time is measured.

Therefore, in the case of this example as well, as in the case of the above example,
Since the heating can be performed uniformly and the temperature can be easily controlled, it is possible to satisfactorily coat the thin object 12 such as a microdrill with a film. Also, the vacuum container 2 can be downsized and the heater 14b need not be frequently cleaned, as in the case of the above example.

Also in the case of this example, the jig 10b may have a structure capable of being divided into a plurality of pieces in the circumferential direction and / or the axial direction. Further, the vacuum seal portion 54 may be cooled in order to protect it from the heat generated by the heater 14b.

In each of the above two examples, the case where the fine object 12 is coated with a film by vacuum vapor deposition has been described.
The film may be coated by the PVD method.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent excessive heating of the tip of the fine article when heating the fine article when coating the film, and to easily measure the temperature of the tip. In addition, it is possible to satisfactorily coat a film on a fine object such as a microdrill which has been conventionally difficult.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of an apparatus for carrying out the method according to the present invention. FIG. 2 is a schematic sectional view showing another example of the apparatus for carrying out the method according to the present invention. 2 ... Vacuum container, 10a, 10b ... Jig, 12 ... Small object, 13 ...
... Handle, 14a, 14b ... Heater, 28a, 28b ... Evaporation source, 34a
...... Pyrometer, 34b ...... Thermocouple.

Claims (1)

[Claims] 1. When coating a fine article with a film by the PVD method,
Attaching a fine article to the jig with its handle and heating the jig to heat the fine article by heat conduction from the jig and measure the temperature of the jig. Method.