JP6629807B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus.

(1) In a conventional plasma treatment of steel, aluminum, titanium, or the like (for example, plasma nitriding heat treatment), a stage (eg, surface of Patent Document 3) to which a negative voltage is applied is installed in a plasma nitriding furnace. A large number of works (for example, 2000 to 3000 in the case of an automobile engine valve) are loaded on the reforming jig 10), and a large number of works are housed in a single closed furnace. In order to heat all the workpieces to the target temperature, the temperature of the entire workpiece is raised to a predetermined temperature by slowly raising the furnace temperature. By applying a negative voltage to all the workpieces to form a cathode and applying a current to generate a glow discharge between the workpiece of the cathode and a furnace housing (chamber) of the anode, nitrogen gas is generated in a plasma state. Is down of nitriding the surface of the work (the nitrided layer formation), collectively performed (hereinafter, referred to as "batch") it is known. (For example, Patent Document 3)

(2) The entire workpiece in the plasma nitriding furnace is heated by a heater or the like at a slow heating rate of 3 ° C./min to a nitriding temperature of 550 ° C. (a target temperature in the case of an iron arrowhead alloy workpiece). Therefore, as shown in the lower part of FIG. 10 of the present application (prior art), it took 120 minutes to raise the temperature to 550 ° C. (For example, Patent Document 1, Patent Document 2)

JP 2004-204355 A JP 2006-213997 A WO2006 / 109540

In a conventional plasma nitriding treatment of steel or the like, a batch method (lot processing method) is used to cope with mass production. The biggest reason for the batch type is that "it takes a lot of time to process one work", and works are processed in a lot in one lot to improve the cost performance per work. It is a way of thinking.
The batch method has one lot for one workpiece and one lot for 1000 pieces, and has a great feature that the processing time does not change. Apparently, it is divided by the number of lots, so that the processing time and cost per piece seem to be small. Therefore, if the number of lots is increased, the cost performance is improved. However, increasing the number of lots increases the size of the equipment, which not only increases initial costs, but also increases the difficulty of quality control due to the increase in size. In addition, once a processing failure occurs, the effect affects the entire lot, so that the risk of large waste and economic loss is likely to occur.
In the event of a breakdown, the furnace itself cannot be used and production cannot be carried out at all.
Moreover, it is not suitable for serial production (line production), small-lot production of many kinds, individual processing and small-quantity production such as experiments for research and development.

  The conventional techniques include an external heat type in which the entire workpiece is heated by a heater from the outside and an internal heat type in which the entire workpiece is heated by a heater installed in the furnace. . (Batch method: for example, Patent Documents 1, 2, and 3) These are methods for heating a work to a nitriding temperature collectively, and do not correspond to individual work heating. In any case, it takes time to heat the work because it is indirect heating by heat conduction or radiation.

A specific example will be described.
An engine valve with 5.5 mm diameter and 100 mm length (height), 2000 pieces of workpieces loaded, external heating furnace, nitriding temperature 550 ° C. The processing steps are: 1) Work loading step → 2) Vacuum evacuation Step → 3) Heating / heating step → 4) Plasma nitriding step → 5) Cooling step → 6) Vacuum breaking step → 7) Work take-out step, which is specifically as follows.

1) Work loading step: 150 minutes (= 28% of total processing time).
Time to arrange (load) workpieces in the processing furnace by hand. The work table is pulled out of the furnace to facilitate the work, and the work is arranged on this table. (Loading.) The loaded work is entirely stored in a furnace in a furnace and subjected to plasma processing. The time required for loading the work is about 2,000 pieces and takes 150 minutes (= 28% of the total processing time). These required times vary greatly depending on the shape and arrangement of the work.

2) Vacuum evacuation step: evacuation time = 10 minutes (= 1.8% of total processing time).
The entire work table is placed in the processing furnace (vacuum chamber), the lid is closed, and the furnace is evacuated with a vacuum pump. In order to eliminate residual oxygen and unnecessary gas components, a high vacuum is once applied, and then replaced with nitrogen gas, washed, etc., and prepared for this treatment. Unless the evacuation process is completed, the work may be oxidized and the plasma process may not be performed normally. Evacuation time: 10 minutes (= 1.8%)

3) Heating / heating step: heating time up to the nitriding temperature of 550 ° C. = 120 minutes (= 22% of the total processing time).
A predetermined temperature (called a nitriding temperature in the case of nitriding) is required for the elements of the processing gas to diffuse and permeate into the inside of the work material. This temperature is the only parameter that can be provided externally with respect to the material and is closely related and important to the material composition and processing specifications. It takes 120 minutes (= 22%) to reach this temperature (550 ° C.).

4) Plasma nitriding step: 60 minutes (including diffusion time) (= 11% of total processing time).
In the case of nitriding, various conditions determined in advance through experiments, etc., that is, the furnace pressure is kept constant, and the nitriding temperature is maintained so that the specified nitriding specifications are obtained, are nitrogen and hydrogen gas, ammonia gas, etc. While flowing at a constant flow rate, plasma is ignited to perform processing. This time is 60 minutes (= 11%)

5) Cooling step: Cooling time = 45 minutes (= 8.3% of total processing time).
Turn off the plasma, stop heating, and wait for the work to cool to a temperature (about 250 ° C) where it does not oxidize: about 45 minutes (= 8.3%)

6) Vacuum breaking step: 5 minutes (= 0.9% of total processing time).
Since the furnace has cooled, the time required for the atmosphere to flow into the furnace and for opening the vacuum door (lid): 5 minutes (= 0.9%)

7) Work take-out step: 150 minutes (= 28% of total processing time).
This is the time required to remove the workpiece from the furnace and remove it to a dedicated tray. It takes 150 minutes (= 28% of the total processing time) for about 2,000 workpieces. These times slightly depend on the shape of the work, the tray, the storage box, and the like.

The total processing time of one batch-type process from 1) to 7) is 540 minutes = 9 hours.
Since 2000 pieces are processed at a time, one piece is calculated as 9 hours (32400 seconds) ÷ 2000 = 16.2 seconds / 1 piece. This production method, which processes 2000 pieces once every 9 hours, is difficult to incorporate into a continuous production line.

Considering these required times, first, in plasma processing, if a work is arbitrarily arranged in a furnace, the processing will vary, so the work must be placed in a place determined in advance by experiments or the like. Since a special jig or the like is used or suspended, and these are formed into a shelf and are multi-tiered, loading and unloading take time. Also, it is difficult for many workers to start at once, and it is difficult to achieve mechanization. For this reason, there is an example in which the same work table is prepared and used alternately to increase the operation rate.
In this example, the loading and unloading of the work takes 150 minutes and 150 minutes, which occupies 28 + 28 = 56% of the entire time.
It is considered that the loading and unloading of workpieces can be performed more flexibly by humans than by mechanization, and if the number of workpieces is large, it is inevitable that much time will be required.

The heating / cooling time of the work requires 120 + 45 = 165 minutes.
In the plasma treatment of metals, the atmosphere (atmospheric pressure, gas type, compounding ratio, etc.) and various plasma conditions (frequency, voltage, power, etc.) are important parameters given from the outside of the material. The only condition is the control of the temperature of the material to be heated from the outside. The processing temperature varies depending on the material and the alloy components contained, but it is generally known that the higher the temperature, the higher the diffusion and penetration rate. For example, it is said that the temperature required for nitriding treatment is 400 to 600 ° C. for steel materials and 300 to 500 ° C. for aluminum alloy materials.

Therefore, there are an internal heat type plasma processing apparatus in which a heater is installed in a vacuum furnace to provide a processing temperature, and an internal heat type plasma processing apparatus which heats the entire vacuum furnace from outside.
In the internal heat type, since the heater is exposed to a vacuum, that is, a processing atmosphere, the material component elements scattered from the heated heater are turned into plasma, which may adversely affect the target plasma processing. Therefore, it is necessary to apply to a low-temperature treatment application where scattering is less likely, or to use a special heating structure or a heater material for a high-temperature treatment.

On the other hand, the external heat type does not scatter heater material components and can be used up to high temperature processing. However, since the entire vacuum vessel is heated, a large heater and electric power are required, and heating takes a very long time. In addition, heat resistance and life of the vacuum container, heat resistance of the seal, and the like must be considered.
Regardless of the internal heating type or the external heating type, if the heater capacity is increased to shorten the heating time, the service life of the furnace wall and heater, the variation in processing due to the increase in the temperature difference in the furnace, the cost of power supply, etc. Problem arises.

Also, even during cooling, the furnace is kept warm so that heat does not escape, so it takes a very long time to cool the furnace. Forcibly speeding up the cooling by using nitrogen or the like also causes problems such as damage to the furnace wall due to a rapid temperature difference and extra cost for cooling such as a coolant. In either case of heating or cooling, it is impossible and not advisable to control the temperature of the furnace in a short time.
In this case as well, the time required for heating and cooling is calculated by dividing the apparent time per unit by dividing it by the number of lots. Therefore, even if it takes some time, it is safer to take time for quality. -There is a tendency to think that it is stable and advantageous in the life of the furnace.

The net nitridation time is 60 minutes.
Although the nitriding time depends on the desired processing specifications such as the thickness of the nitride layer, the batch-type processing does not depend on the number of works in the furnace. The same processing time is required for one workpiece or 100 workpieces. Therefore, in batch processing, it is more cost-effective to load as many workpieces as possible. If the number of lots is less than the predetermined number, it is not only disadvantageous in terms of cost, but also it is necessary to operate the processing conditions according to the number of insufficiency lots.

As a processing specification, for example, if the thickness of the nitride layer is required to be 100 μm, the current technology requires a nitriding time of several hours or more, and the processing specification requires only about 60 minutes as in the case of this engine valve. There are many.
As in the case of heating and cooling, the plasma density in the furnace is kept low, and the treatment over time can be performed uniformly and evenly. There is a tendency to think that it may take time.

  As other times, the evacuation and vacuum break times are also influenced by the size of the vacuum chamber, the balance with the exhaust device, the pretreatment method and the ultimate vacuum.

  As shown in the above example, even in the case of a net nitriding treatment of 60 minutes, a total of a series of operation time accompanying the nitriding treatment takes an overwhelmingly long time of 9 hours. Such a batch-type nitriding system can perform a large amount of processing at a time and is advantageous in cost. However, since a single processing unit is large, the risk of occurrence of a defect is large, and automation and line processing cannot be performed. It is difficult, and if something breaks down, production will not be possible at all, and it is not suitable for small-lot production at all.

  Also, if the number of workpieces housed in the chamber is reduced, the processing conditions will be different, and there will be a problem that a uniform quality nitrided layer cannot be formed, so that it is difficult to perform small-scale production and production adjustment.

  In view of the above-mentioned drawbacks of the prior art, the present invention makes it possible to make the quality of a large number of workpieces simultaneously subjected to plasma processing (for example, the quality of a nitride layer formed by plasma processing) uniform with little variation. It is an object of the present invention to provide a plasma processing apparatus capable of minimizing the generation of defective products and capable of coping with small-quantity production.

In order to achieve the above object, the present invention has the following configuration.
<Invention according to claim 1>

A first high-frequency plasma generation electrode to an n-th high-frequency plasma generation electrode for generating high-frequency plasma for plasma-treating the work are provided in one vacuum chamber of the chamber, and the first high-frequency plasma generation electrode to the n-th high-frequency plasma generation electrode are provided. A plasma processing apparatus characterized in that it is possible to individually perform the above-described plasma processing on a work at each plasma processing position of a high-frequency plasma generating electrode .

<Invention according to claim 2>

A first high-frequency plasma generation electrode to an n-th high-frequency plasma generation electrode for generating high-frequency plasma for plasma-treating the work are provided in one vacuum chamber of the chamber;
A first induction heating coil to an n-th induction heating coil for inducing an induction current in the work to heat and heat the work is provided in the one vacuum chamber, and the first induction heating coil to the n-th induction. In each heating processing position of the heating coil, the workpiece can be individually heated and heated, and each of the first to n-th high-frequency plasma generating electrodes has a plasma processing position. Wherein the plasma processing can be performed individually on each of the workpieces .

<Invention of Claim 3>

The chamber comprises a first chamber forming body and a second chamber forming body,
The first chamber forming body and / or the second chamber forming body can be opened and moved to open the chamber, and the first chamber forming body and / or the second chamber forming body can be opened. One can be closed and movable to bring the chamber to the closed state,
The first high-frequency plasma generation electrode to the n-th high-frequency plasma generation electrode are provided in a portion of the second chamber forming body where the one vacuum chamber is formed, and the one of the first chamber forming body The plasma processing apparatus according to claim 1, wherein a first work set part to an n-th work set part for setting a work is provided at a part where a vacuum chamber is formed .
The "work supply means" and the "work take-out means" include those in the form of separate means and those in which one means is also used.

  As is clear from the above description, the following effects can be obtained in the present invention.

<Effect of Invention of Claim 1>
(1) Induction heating is direct heating in which an induction current is applied to a work to generate heat. Unlike indirect heating such as radiation or heat conduction by a heater, not only the work can be heated for a short time, but also the outside heating. It is notable to heat extra parts such as a chamber as in a thermal furnace, which saves energy and saves only the work.

  For example, as shown in the graph of Example 1 of the present invention and the graph shown in FIG. 10, an engine valve having a diameter of 5.5 mm and a length (height) of 100 mm can be heated to 550 ° C. under induction heating conditions (conditions: 400 kHz, 500 w). Can be performed in a heating time of 20 seconds (0.33 minutes) or less.

The cooling time can be from 550 ° C. to 250 ° C. within 90 seconds (1.5 minutes).
That is, the time required for heating and cooling is about 110 seconds (1.83 minutes), so that it takes 120 minutes to raise the temperature up to 550 ° C. and 20 minutes to cool down, which is 140 minutes in total, compared to the conventional plasma processing apparatus. Therefore, there is an effect that the short heating / cooling processing time of 1.83 / 140 (≒ 1/177) is realized.

(2) According to the above (1), the conventional batch-type nitridation processing time required a total of 200 minutes (120 minutes for temperature increase + 60 minutes for nitridation + 20 minutes for cooling) according to the embodiment of the present invention. In the case of 1, the heating time is slightly less than 62 minutes (20 seconds for temperature rise + 60 minutes for nitriding time (for the time being the conventional processing time) + 90 seconds for cooling). This has the effect of significantly reducing the processing time.

(3) Since the workpiece is heated by induction heating, not only can the heat treatment time be simply shortened, but also the workpiece to be processed can immediately transition to a high temperature or a low temperature. This has the effect of widening the width and enabling the nitriding temperature profile operation.

(4) In one chamber, an induction heating coil, a high-frequency plasma generation electrode, a high-frequency oscillator for heating, and a high-frequency oscillator for plasma are used as work processing units, and a plurality of work processing units (for example, 100 stations, A multi-processing (connected or unit-type) plasma processing apparatus for simultaneously processing a large number of works by providing work sets corresponding to each of the plurality of work processing sections. It is possible.

  In this multi-processing type plasma processing apparatus, each work is heated by the corresponding induction heating coil, and is subjected to plasma processing by the corresponding plasma. Plasma treatment is performed under uniform heat treatment conditions with no variation, and thus, for example, a formed nitride layer of each work can be made to have high uniformity and high quality with extremely small variation.

Further, even if one work processing unit becomes defective, the defective work is generated only there, and the other work does not become defective. It is difficult.
In addition, since the heating high-frequency oscillator and the plasma high-frequency oscillator can be individually controlled, for example, a large number of works for performing tests under different heating conditions and plasma conditions and simultaneously processing works having different thicknesses. Enable processing type.
The effect of the multi-processing type plasma processing apparatus will be described in more detail with reference to the effect of the third aspect of the present invention.

<Effect of Claim 2>
In addition to the same effects as the first aspect of the present invention, the following effects can be obtained.
(1) If a high-frequency oscillator for heating and a high-frequency oscillator for plasma use a self-excited high-frequency oscillator, the conversion efficiency is high and no extra device such as reflected power detection is required. A system can be built.

(2) Since the printed circuit board is detachable, it can quickly respond to failures, specification changes, or maintenance, and easily realizes plasma processing under different conditions (including different workpieces) by changing the printed circuit board. .

(3) Since the dipole plasma processing is a plasma generation method in which dipole electrodes are arranged on both sides of a work, the plasma density is high, and the plasma processing is optimal for individual plasma processing. There is an effect that a high quality nitride layer can be formed.

(4) The outputs of the heating high-frequency oscillator and the plasma high-frequency oscillator can be small.
For example, a 2 MHz, 50 W plasma high frequency oscillator is sufficient for nitriding an engine valve having a diameter of 5.5 mm and a length (height) of 100 mm. A high-frequency oscillator for heating at 400 KHz and 500 W is sufficient for heating the engine valve to 550 ° C. in 30 seconds and maintaining the temperature.

Since both outputs are small, they can be realized in a mounting form on a printed circuit board.
The printed circuit board can be manufactured at low cost and can be easily replaced, so that it can respond quickly to failures and maintenance.
Further, there is an effect that it is possible to cope with a change in output or frequency, which occurs when a work is changed or a specification is changed, by replacing a board or the like.

<Effect of Invention of Claim 3>
In addition to achieving the same effects as the invention according to any one of claims 1 and 2, a work processing unit is formed by an induction heating coil, a high-frequency plasma generating electrode, a high-frequency oscillator for heating, and a high-frequency oscillator for plasma. A plasma processing apparatus in which a plurality of work processing units are united or connected by providing a first work processing unit to an n-th work processing unit, which are work processing units, in a second chamber forming body. The effects described below are achieved.

(1) Work supply means for automatically and simultaneously supplying the work to the first to n-th work set sections provided in the first chamber, and work take-out means for automatically and simultaneously taking out the work. Thus, the loading and unloading of all the workpieces can be performed in a very short time, for example, within 10 seconds, so that the mechanization / automation of the workpiece transfer is facilitated.
Conventionally, a lot of time was spent loading and unloading the work from the chamber to the work set part, but according to the present invention, the work set part is not moved and only the work is simultaneously transferred, so the work time is greatly reduced And a system that requires no human intervention. In particular, it is convenient to perform plasma processing on ultra-small components such as medical device components.

(2) The workpieces to be processed in the first to n-th workpiece processing units are heated by a dedicated induction heating coil and subjected to plasma processing by a dedicated high-frequency plasma generating electrode. The accurate temperature control and the accurate plasma control performed individually give an effect that uniform processing quality (for example, a nitride layer) can be realized by giving an optimum plasma processing condition to each work. (Equalization of individual high quality)

(3) When the number of workpieces to be processed is small, an unused workpiece processing unit is not operated, so that it is possible to cope with small-quantity production with a necessary minimum energy consumption, and it is possible to maintain uniform processing quality. Eliminate waste in small-lot production and save energy). Therefore, production planning and production adjustment while maintaining uniform processing quality can be efficiently performed without waste of energy.

(4) When one of the workpiece processing units fails, the supply and operation of the workpiece to the failed workpiece processing unit are stopped, and the plasma processing in another normally operating workpiece processing unit can be advanced. To play.

(5) The system of a 100-connected work processing unit incorporated in a production line is used as a condition search, research / experimental device, for example, it is possible to simultaneously perform experimental results under temperature control conditions of 100 samples. It is very effective.
That is, it is possible to obtain experimental data of 100 samples under, for example, nitriding conditions in only about 60 minutes, which is 1/100 of the time required for obtaining experimental data in the related art. The conventional technology has the effect that the long condition search time can be greatly reduced, and the experiment / research cycle can be accelerated.
Therefore, when it is possible to cope with many kinds of small quantities, or when it is used for condition setting and R & D, for example, the nitridation experiment which was long in the conventional technology can be greatly shortened, the research cycle can be accelerated, and the equipment can be reduced in size and shorter. This is convenient for experiments for research and development, multi-product handling, etc.

(6) Since the chamber is not heated, the temperature does not become high, so that the room temperature in the factory is not raised.

FIG. 2 is a conceptual diagram of Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view illustrating a closed state of the chamber according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an open state of the chamber according to the first embodiment of the present invention. FIG. 2 is a plan view showing a work setting unit, a work take-out unit, and a chamber according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a work processing unit in which a work is not set according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a work processing unit in a state where the work according to the first embodiment of the present invention is set. FIG. 2 is a cross-sectional view illustrating an open state of the chamber according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view of the work processing unit in a state where the work according to the first embodiment of the present invention is set, as viewed from another direction. FIG. 2 is an equivalent circuit diagram of noise radiation according to the first embodiment of the present invention. 6 is a graph showing the processing time according to the first embodiment of the present invention and the processing time according to the related art. FIG. 6 is a cross-sectional view illustrating a closed state of a chamber according to a second embodiment of the present invention. FIG. 10 is a cross-sectional view illustrating a work processing unit in a state where a work according to a third embodiment of the present invention is set.

  Hereinafter, an embodiment which is the best mode for carrying out the present invention will be described. However, it is not intended to limit the present invention to only these examples. In the description of the embodiments described later, the same components as those in the above-described embodiments will be denoted by the same reference numerals, and redundant description will be omitted.

In the first embodiment of the present invention shown in FIGS. 1 to 10, the plasma processing apparatus 1 has the following configuration.
This is a place where one unprocessed work 2N composed of an engine valve is set, and a bias voltage is applied from a bias applying power supply 3 (FIG. 9) which is a DC power supply to rotate the unprocessed work 2N to a negative voltage. Work set unit 4 controlled as described above,
A cooling medium (generally, water-cooled) is passed through a hollow tube for heating the unprocessed work 2N set in the work setting section 4 by high-frequency induction heating at 400 kHz. The induction heating coil 5 (the cooling medium supply unit is omitted),
A high-frequency plasma generation electrode 7 which is a dipole electrode for generating a 2 MHz high-frequency plasma 6 and which is arranged in a non-contact close proximity to the unprocessed work 2N;
A heating high-frequency oscillator 9 for supplying high-frequency heating power to the induction heating coil 5;
A high-frequency plasma oscillator 10 for supplying high-frequency plasma power to the high-frequency plasma generation electrode 7;
A work processing unit 8 that performs a plasma process (here, “nitriding process”) including an induction heating coil 5, a high-frequency plasma generating electrode 7, a high-frequency oscillator 9 for heating, and a high-frequency oscillator 10 for plasma;
A high-frequency unit 11 including a high-frequency oscillator 9 for heating and a high-frequency oscillator 10 for plasma generation;
A work set section driving means 22 for rotating the work set section 4,
Work processing units 8-1 to 8-100 (hereinafter, also referred to as “work processing unit 100 connection” to “100 connection”) in which 100 work processing units 8 are provided.
A chamber forming body 12 having 100 work setting sections 4 corresponding to the work processing sections 8-1 to 8-100, and the chamber forming body 12 and the chamber forming body 12 can be closed and opened. A chamber 14 including a chamber forming body 13 having a work processing unit 8-1 to a work processing unit 8-100;
A high-frequency section 11-1 to a high-frequency section 11-100 composed of the high-frequency section 11 corresponding to each of the work processing sections 8-1 to 8-100;
A vacuum pump 16 for evacuating the air in the chamber 14,
A gas supply means 20 including a gas cylinder 17 for supplying a processing gas into the chamber 14, a gas control valve 18, and a gas supply pipe 19;
A power supply unit 21;
A cooling pump 23;
Temperature measuring means 24 for measuring the temperature of the work,
A work setting means 25 for automatically and simultaneously supplying the unprocessed work 2N to all the work setting units 4 of the work processing units 8-1 to 8-100,
A work take-out means 26 for automatically and simultaneously taking out the processed works 2T set in all the work setting sections 4,
At the time of setting and taking out the work, the chamber forming body 13 is moved so that the induction heating coil 5 and the high-frequency plasma generating electrode 7 are separated from each other at a position where they do not interfere with the setting and taking out of the work 2, so that the chamber is opened. Chamber opening and closing means 28 for closing during plasma processing;
Bias forming DC power supply 3, work set driving means 22, high-frequency oscillator 9 for heating, high-frequency oscillator 10 for plasma generation, vacuum pump 16, gas control valve 18, power supply 21, cooling pump 23, work setting means 25, work take-out And a controller 27 for automatically controlling the chamber opening and closing means 28.

The work set part 4 is provided in the chamber forming body 12.
The induction heating coil 5 and the high-frequency plasma generating electrode 7 are provided in the chamber forming body 13.
A high-frequency unit 11 (high-frequency oscillator 9 for heating and high-frequency oscillator 10 for plasma generation) is provided outside the chamber forming body 13.

The chamber forming body 12 and the chamber forming body 13 are separated (the chamber forming body 13 is opened),
100 unprocessed works 2N are simultaneously set in the work setting unit 4 of the work processing units 8-1 to 8-100 by the work setting unit 25;
Closing the chamber forming body 13;
The inside of the chamber 14 is evacuated,
The high frequency power for induction heating is supplied to the induction heating coil 5 to raise the temperature of the untreated work 2N to a target temperature (550 ° C. in this case) by an induced current induced in the untreated work 2N,
Supplying a processing gas 15 into the chamber 14,
The high-frequency plasma generation electrode 6 is supplied to the high-frequency plasma generation electrode 7 to generate the high-frequency plasma 6, a bias voltage is applied to the unprocessed work 2 </ b> N, and the unprocessed work 2 is biased to a negative voltage to perform plasma processing. (Here, nitriding treatment) to form a treated work 2T,
Cool to cooling temperature,
Vacuum break,
The chamber forming body 13 is set in a chamber open state,
All the processed workpieces 2T are simultaneously taken out by the work take-out means 26,
A new unprocessed work 2N is simultaneously supplied to each work setting unit 4 by the work setting means 25, and is set.
The above operation processing is automatically performed.

The chamber 14 is made of a conductive member and is grounded. The high-frequency plasma generating electrode 7 is a dipole electrode made of a pair of symmetric electrodes, and a shield cover 30 made of a conductive member integrated in the chamber 14 in a conductive form. Is provided, a shield body 31 is formed by the chamber 14 and the shield cover 30, and the high-frequency power supply unit 11 (the high-frequency oscillator 10 for plasma generation and the high-frequency oscillator 9 for heating) is provided in the shield cover 30,
With the above configuration,
A mechanism is realized in which noise radiation due to high frequency generated in the high-frequency oscillator 9 for heating, the high-frequency oscillator 10 for plasma generation, and the shield body 31 does not leak outside.
The high-frequency oscillators for the plasma generating high-frequency oscillator 10 and the heating high-frequency oscillator 9 are self-excited high-frequency oscillators that do not require a matching box.

The high-frequency oscillator 9 for heating and the high-frequency oscillator 10 for plasma generation are formed in a printed circuit board mounting form, and are detachably connected to respective dedicated connectors (not shown) provided in the shield cover 30 for easy replacement. It has been made possible.
The heating high-frequency oscillator 9 can be replaced with a printed circuit board in the range of 300 kHz to 2 MHz.
Further, a cooling fan 38 for cooling the high-frequency oscillator 9 for heating and the high-frequency oscillator 10 for plasma generation is provided.

  Each of the work processing units 8-1 to 8-100 is a partition member 29 (shield plate) made of a conductive member so as not to be affected by the electrical conditions and physical conditions of the high-frequency plasma of the adjacent work processing unit. The work processing units 8-1 to 8-100 maintain independence of electrical and physical conditions.

  The gas supply pipe 19 is supplied with the processing gas 15 to each of the workpiece processing units 8-1 to 8-100, and the amount thereof is adjusted so that the processing gas concentration in the entire chamber becomes a predetermined gas concentration. The divided gas is supplied to the 100 gas supply pipes 19, and the amount of the gas supplied while maintaining the supply is supplied.

Further, a gas concentration measuring means (not shown) is provided in each of the work processing units 8-1 to 8-100, and based on the test results of the gas concentration measuring means, the work processing units 8-1 to 8-1. The amount and timing of gas supplied to each of the processing units 8-100 may be controlled by the gas control valves 18 (there are 100).
The number of gas supply pipes 19 may be one or several. In this case, it is preferable that the location from which the gas is blown out is set by specifying the location where the gas concentration spreads quickly and uniformly.
The gas concentration measuring means is provided at a plurality of locations or in all the workpiece processing units, so that the gas concentration of all the workpiece processing units is constantly monitored so that a predetermined gas concentration is always maintained, or that all the workpieces have a target gas concentration. Is controlled.
It is preferable that the gas concentration in all the workpiece processing units is constantly monitored, and the plasma processing is started with all the workpiece processing units at a predetermined gas concentration.

The power supply to the induction heating coil 5 and the high-frequency plasma generation electrode 7 may be performed while the high-frequency power for induction heating is supplied to the induction heating coil 5 when there is mutual interference. The high-frequency power for plasma generation is stopped, and the high-frequency power for induction heating to the induction heating coil 5 is stopped while the high-frequency power for plasma generation is being supplied to the high-frequency plasma generation electrode 7.
The supply time and stop time of the power to the high-frequency plasma generating electrode 7 and the induction heating coil 5 are determined when the work 2 is an engine valve having a diameter of 5.5 mm, a length (height) of 100 mm, and a face portion having a diameter of 30 mm. , About 0.5 to 5 seconds.

  Even when the workpiece is heated during the high-temperature treatment, the induction heating coil 5 is cooled by a cooling medium such as a cooling medium flowing in the coil and is kept at a low temperature. Therefore, the adverse effect of the coil component on the work can be extremely reduced.

A specific example will be described.
The work 2 is an engine valve having a diameter of 5.5 mm, a length (height) of 100 mm, and a diameter of a face portion of 30 mm. The induction heating power is 400 kHz, 500 W to 150 W, and the plasma generation power is 2 MHz, 30 W to 50 W. is there.
The high-frequency oscillator for heating is preferably determined according to the size and material of the work.

The heating time of the workpiece 2 up to 550 ° C. by the induction heating of 400 kHz and 500 W is 20 seconds or less. The cooling time of the work 2 from 550 ° C. to 250 ° C. is 90 seconds or less.
The total processing time is a little less than 62 minutes (20 seconds for temperature rise + 60 minutes for nitriding (for the time being the conventional processing time) + 90 seconds for cooling), which is less than one-third of the conventional batch type (200 in total). (120 minutes for heating + 60 minutes for nitriding + 20 minutes for cooling).

Now, since the nitriding time is reduced to less than one third in total, the operation is performed by setting the workpiece processing units for processing one by one to a 100-connected unit form (nitriding unit 7-1 to nitriding unit 8-100). And try to calculate. For convenience of calculation, 62 minutes is set to 60 minutes.
In the conventional batch method (2,000 charge), the processing operation is performed once or twice a day based on the loading work time and the processing time, so that the number of processes of 2000 to 4000 pieces can be obtained per day.

On the other hand, in the plasma processing apparatus 1 of the 100-connected system of the nitriding units 8-1 to 8-100, it is installed in an automated manufacturing line and operates unattended for 24 hours. 2400 processing numbers are obtained.
Although the nitridation time is calculated with the conventional 60 minutes, the dipole plasma is expected to be able to substantially reduce the nitridation time. Therefore, if the 60 minutes is reduced to 50 minutes, 2400 treatments are obtained. This is a calculation that results in 84 concatenations. In such a decentralized system, of course, the time of the entire nitriding process directly affects productivity and the number of connections (initial cost).

Since only a single processing unit can be operated, processing can be performed from at least one processing unit. (Of course, a processing time of 60 minutes is required.)
Furthermore, even in the connection operation of every 100 pieces, the nitriding treatment can be performed by monitoring and adjusting the nitriding condition for each piece, so that uniformity with small variation in the quality of the nitrided layer is realized and the uniformity is achieved. Can be easily adjusted.

  The work set unit 4 is supported on a rotating shaft 45 to which a bias voltage is applied so as to rotate, and a rotor 46 made of a permanent magnet is provided in a projecting portion 47 projecting below the chamber 14 on the rotating shaft 45. An electromagnet 48 for rotating the rotor 46 is provided on the outer periphery of the protruding portion 47 to form the work set portion driving means 22 composed of a motor.

A dummy electrode 50 is provided in the chamber 14 so as to be insulated from the chamber 14.
A switch 51 is connected to the bias forming DC power supply 3 so as to apply a bias voltage to the dummy electrode 50, and switches the voltage application of the bias forming DC power supply 3 to the dummy electrode 50 and the work set unit 4.

When the changeover switch 51 is set to the dummy electrode 50 side, + ions in the plasma do not go to the work set part 4 and the set work 2 which are grounded (potential 0), but are drawn to the dummy electrode 50 which is a negative electrode. Will be done.
In addition to preventing unnecessary ions from being mixed, it is easy to control the amount of the ions to be attached. In addition, it is possible to eliminate the evacuation work for cleaning the inside of the chamber.

40 is a vacuum gauge, 41 is a pressure control valve, 42 is a seal, and 44 is a viewing window.
A cooling passage 43 through which a cooling medium flows to prevent the seal 42 from being damaged by heating is provided near the seal 42 in the chamber 13.

  It is preferable to use a high frequency of 2 MHz for induction heating of a micro component (for example, a needle) such as a medical device component.

  The chamber open state is realized by a mode in which the chamber forming body 12 and the chamber forming body 13 are opened and movable or one of them is opened and moved, and the chamber closed state is realized by the chamber forming body 12 and the chamber forming body 13. Or any one of them can be closed and movable.

The main difference between the second embodiment of the present invention and the first embodiment shown in FIG. 11 is that the work set driving means includes a single drive motor 52 and a rotation transmission mechanism such as a sprocket or a pulley provided on each rotary shaft 45. The point is that a work set section driving means 55 comprising a means 53 and a power transmitting means 54 such as a chain or a belt for transmitting the rotational power by communicating the rotation transmitting means is formed.
It is also possible to use a plurality of drive motors 52 (for example, 10 drive units each drive 10 work set units 4).

The third embodiment of the present invention shown in FIG. 12 is mainly different from the first embodiment in that a work set portion 57 is provided between the work set portion 4 and the high-frequency plasma generating electrode 7, and one work 2 is set. A plasma provided with an induction heating coil 58 for induction heating the work 2 set in the work setting section 57 and a heating high-frequency oscillator 59 for supplying the induction heating coil 58 with high-frequency induction heating power. The point is that the processing device 60 is formed.
With a 100-connected configuration of the work processing units 8-1 to 8-100, twice the processing capacity of the plasma processing apparatus 1 is realized.

The supply of the induction heating high-frequency power to the induction heating coil 5 and the induction heating coil 58 is preferably performed by one heating high-frequency oscillator 9. Specifically, it is assumed that the induction heating coil 5 and the induction heating coil 58 are formed by elongating the coils.
As described above, nitriding of, for example, two to six engine valves can be performed by the bending configuration of one induction heating coil and one heating high-frequency oscillator.

  Further, depending on how the induction heating coil is formed, for example, a work coil configuration in which a plurality of (not so many) works are simultaneously heated by one induction heating coil can be realized, so that a plurality of works (up to about 2 to 6) can be simultaneously formed. Heating is also possible, and plasma processing of multiple workpieces is possible by disposing the dipole electrode.Work transfer can be separated as much as possible so that there is no mechanical interference around the chamber when the chamber is opened Therefore, since a plurality of (2 to 6) pieces can be transferred at the same time, the simultaneous plasma processing of a plurality of works can be realized. Although it slightly deviates from the expression "individual processing", such a form is also included in the technical scope of the present invention.

<Invention described in Appendix 1>
  A first chamber forming body;
  A second chamber forming body;
  A first chamber forming body and the second chamber forming body, and the first chamber forming body and / or the second chamber forming body can be opened and movable to a chamber open state; And a chamber capable of closing and moving the first chamber forming body and / or the second chamber forming body to a closed state;
  A work setting section for setting a work provided in the first chamber forming body;
  An induction heating coil provided in the second chamber forming body, which induces an induced current in the work set in the work setting section and heats the work;
  A heating high-frequency oscillator for supplying high-frequency heating power to the induction heating coil,
  A high-frequency plasma generation electrode for generating high-frequency plasma provided in the second chamber forming body;
  A high frequency oscillator for plasma for supplying high frequency power for plasma to the high frequency plasma generating electrode;
  A vacuum pump for evacuating the air in the chamber, and a gas supply unit for supplying a processing gas into the chamber;
  The induction heating coil and the high-frequency plasma generating electrode, the work is set in the work set portion and the chamber is in a state where it is separated from a position that does not hinder removal, and the chamber is opened.
  Set an unprocessed work in the work set section,
  In the closed state of the chamber,
  Perform the evacuation if necessary,
  The untreated work is heated to a predetermined temperature by the induced current,
  Supplying the processing gas,
  The high-frequency plasma is generated, and the unprocessed work can be plasma-processed to form a processed work,
  A plasma processing apparatus, wherein the processed work is taken out with the chamber opened.
<Invention described in Appendix 2>
  The high-frequency plasma generating electrode is a dipole electrode, and / or one or both of the heating high-frequency oscillator and the plasma high-frequency oscillator are self-excited, and the heating high-frequency oscillator and / or the plasma high-frequency oscillator are either 2. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is mounted and formed in a form of a printed board, and the printed board is provided in a detachable form.
<Invention described in Appendix 3>
  Induction heating coil, high-frequency plasma generating electrode, high-frequency oscillator for heating, high-frequency oscillator for plasma as the work processing unit,
  The first to n-th work processing units including the work processing units are provided in the second chamber forming body,
  First to n-th worksets comprising a workset are provided in the first chamber forming body;
  Work supply means for automatically and simultaneously supplying the first work to the n-th work, which are works, to the first work set to the n-th work set in the chamber opened state,
  A work take-out means for automatically and simultaneously taking out the first work to the n-th work set in the first work set portion to the n-th work set portion in the chamber opened state is provided. The plasma processing apparatus according to any one of supplementary notes 1 and 2, wherein
  The "work supply means" and the "work take-out means" include those in the form of separate means and those in which one means is also used.

  INDUSTRIAL APPLICABILITY The present invention is mainly used in an industry in which a plasma processing apparatus is incorporated in a manufacturing process line and used.

1: plasma processing apparatus,
2: Work,
2N: unprocessed work,
2T: processed work,
3: Bias forming DC power supply,
4: Work set part,
5: induction heating coil,
6: high frequency plasma,
7: High frequency plasma generating electrode
8, 8-1 to 8-100: Work processing unit 9: High-frequency oscillator for heating,
10: High frequency oscillator for plasma generation,
11, 11-1 to 11-100: high frequency part,
12: chamber forming body,
13: chamber forming body,
14: chamber,
15: processing gas,
16: vacuum pump,
17: Gas cylinder,
18: gas control valve,
19: gas supply pipe,
20: gas supply means,
21: power supply part,
22: work set unit driving means,
23: cooling pump,
24: temperature measuring means,
25: Work set means,
26: Work take-out means
27: control unit,
28: means for opening and closing the chamber
29: partition member,
30: shield cover,
31: shield body,
33: Plasma generation side step-up transformer,
34: midpoint,
38: cooling fan,
40: vacuum gauge,
41: pressure regulating valve,
42: seal,
43: cooling path,
45: rotating shaft,
46: rotor,
47: protrusion,
48: electromagnet,
50: dummy electrode,
51: changeover switch,
52: drive motor,
53: rotation transmission means,
54: power transmission means,
57: work set part,
58: induction heating coil,
59: High-frequency oscillator for heating,
60: Plasma processing device.

Claims (3)

A first high-frequency plasma generation electrode to an n-th high-frequency plasma generation electrode for generating high-frequency plasma for plasma-treating the work are provided in one vacuum chamber of the chamber;
At each of the plasma processing position of said first high-frequency plasma generating electrode to the n high-frequency plasma generating electrode, the workpiece, respectively make it possible to the plasma processing individually,
The chamber comprises a first chamber forming body and a second chamber forming body,
The first chamber forming body and / or the second chamber forming body can be opened and moved to open the chamber, and the first chamber forming body and / or the second chamber forming body can be opened. One can be closed and movable to bring the chamber to the closed state,
The first high-frequency plasma generation electrode to the n-th high-frequency plasma generation electrode are provided in a portion of the second chamber forming body where the one vacuum chamber is formed,
A portion for forming the single vacuum chamber of the first chamber forming member, the work set portion of the first workpiece setting section to the n-th is provided for setting said workpiece,
The plasma processing apparatus , wherein the plasma processing is performed on the workpieces set in the first to n-th workpiece setting units at the plasma processing position . Work supply means for automatically and simultaneously supplying the first work to the n-th work, which are works, to the first work set to the n-th work set in the chamber opened state,
A work take-out means for automatically and simultaneously taking out the first work to the n-th work set in the first work set portion to the n-th work set portion in the chamber opened state is provided. The plasma processing apparatus according to claim 1, wherein: A plurality of work sets are provided for one high-frequency plasma generation electrode that is each of the first high-frequency plasma generation electrode to the n-th high-frequency plasma generation electrode, and the one high-frequency plasma generation electrode is provided. 3. The plasma processing apparatus according to claim 1, wherein each of the plurality of works set in the plurality of work setting units can be subjected to plasma processing.