JPH0496B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a plasma branching treatment method for subjecting the surface of resins such as polypropylene (PP) and polyethylene (PE) to plasma treatment in order to modify their surfaces. .

Background of the Technology In recent years, for example, there has been a tendency for automobile parts to be made of resins that are lightweight and have excellent designs. However, when relatively inexpensive PP, PE, etc. It is known that the adhesion between the paint film and the paint film is poor, resulting in problems such as delamination. One way to eliminate this problem is to perform plasma treatment, which involves exposing the surface of the object to be coated, such as PP or PE, to glow, corona discharge, or high-frequency discharge to oxidize (introduce polar groups) or etch (improve the anchoring effect) the surface. The technology is known.

By the way, when plasma-treating resin parts such as bumpers used in automobiles, a large processing container is required for the following reasons.

(1) Resin parts such as bumpers are large and have complex shapes.

(2) Since it is necessary to maintain a vacuum inside the processing container, a batch processing production method is adopted, so it is necessary to process many pieces at the same time.

On the other hand, as the processing container becomes larger, it becomes difficult to make the plasma concentration uniform in each part of the container, and as a result, there is a problem that the processing properties of the objects to be processed placed in the processing container become uneven. There has occurred.
An example of a conventional plasma processing apparatus in which such a problem occurs is shown in FIGS. 3a and 3b. In these figures,
An evaluation was performed by measuring the contact angle of the surface of the processed object after treatment between the processed object (not shown) installed in section A and the processed object (not shown) installed in section B. The treatment performance of the one installed in section A was inferior to that of the one installed in section B, and non-uniformity was observed in the treatment performance even within the same object to be treated. This is because the plasma irradiation is shielded by the object placed in section B.
This is thought to be because the life of the plasma in part A is impaired.

In order to solve these problems, Fig. 4 a and b
As shown in Figure 2, when a plurality of plasma inlets were installed in the processing container, the objects to be processed within the processing container could be uniformly processed. As described above, in order to equalize the plasma concentration at each location within a large-scale processing container, it is preferable to install a plurality of plasma inlets in the processing container. However, installing one set of plasma generation system devices for each inlet poses problems in terms of equipment investment and power saving. Note that each reference numeral in FIG. 3 and FIG. 4 indicates the same component as each same reference numeral in FIG. 1 and FIG. 2, which will be described later.

Purpose of the Invention In view of these points, the present invention generates microwaves with a magnetron before generating plasma outside the processing container when processing a plurality of large, complex-shaped resin parts at the same time. To provide a plasma processing method that achieves uniform processing, reduction of equipment investment, and power saving by distributing waves into a plurality of waves to generate plasma in each path and introducing the plasma into a processing container. It is something.

Structure of the Invention In a method of generating microwave discharge plasma outside a processing container, introducing the plasma into the container, and irradiating the surface of a workpiece placed in the container with the plasma, the plasma is oscillated by a magnetron. The distributed microwaves are distributed to a plurality of parts by a distributor, and the distributed microwaves are guided to a plasma generation mechanism consisting of a plasma generation furnace and a plasma generation tube provided corresponding to the number of distributions, and each of these plasma generation The plasma generated by the mechanism was introduced into the processing container through a plurality of plasma introduction ports provided in the processing container.

Embodiment FIGS. 1 and 2 show an embodiment of a microwave discharge plasma processing apparatus for carrying out the method of the present invention. In FIGS. 1 and 2, 1 is a processing container made of, for example, SUS304 and has a cylindrical body and a mirror cover; 2 is a microwave oscillator with a built-in magnetron (oscillation tube) that emits, for example, a 2450 MHz microwave; 3 is a distributor made of aluminum and distributes microwaves 1:1; 4a, 4b;
is an isolator to prevent reflected radio waves from returning to the oscillation tube, 5a and b are power monitor detectors that monitor the reflected power, 6a and b are matching devices to minimize the reflected power, and 7a and b are micro Waveguides 9a, b for transmitting waves to the plasma generating furnaces 8a, b
10a and 10b are plasma generation tubes made of quartz glass installed in the generation furnace 8 and partially exposed to microwaves and through which processing gas passes, and 10a and 10b are plasma generation tubes 9a and 9b made of Pyrex glass. Fluoro connectors made of Teflon are used to airtightly connect the transport pipes 11a and 11b, 12a and b are Teflon fluoro connectors that are hermetically joined to the transport pipes 11a and b and the shower pipes 14a and b, and 13a and b are connected to the processing container 1. This is the plasma introduction port. 15a, b, 16a,
b is a shower tube similar to the shower tubes 14a, b, and is connected to the generation furnaces 17a, b, 18a, b, respectively, via plasma inlets 22a, b, 23a, b in the same way as the shower tubes 14a, 14b. are doing. 19a, b, 20a, b, 21a, b are exhaust ports connected to a vacuum pump (not shown) via piping (not shown), and plasma inlet ports 23a, b, 23a, b, 22a, b, respectively.
It is placed in a position opposite to.

The generation tubes 9a, b are connected to a gas cylinder (not shown) via a tube (not shown). The isolators 4a, b, power monitors 5a, b, matching boxes 6a, b, waveguides 7a, b, and plasma generating furnaces 8a, b are mainly made of aluminum. In addition, each shower pipe 14a, b, 15a,
b, 16a, and b are arranged in the axial direction within the processing container 1, and are spaced apart from each other by about 60°.
These shower tubes have a large number of plasma injection ports (not shown) and are designed to uniformly inject plasma into the processing container 1.

After putting the object to be processed (not shown) into the processing container 1, the inside of the container 1 is reduced to a predetermined vacuum pressure using a vacuum pump (not shown), and the processing gas in the cylinder (not shown) is pumped into the tube or generation tube. It is supplied into the container 1 via 9a, b, etc. and set to a predetermined vacuum pressure. The magnetron in the microwave oscillator 2 oscillates a 2450MHz microwave. The generated microwave is divided into two parts by a separation/distributor 3, and isolators 4a, b, power monitor detectors 5a, b,
It is transmitted to the generating furnaces 8a, b via matching boxes 6a, b and waveguides 7a, b. In order to minimize the reflected power, the matching devices 6a and 6b are adjusted in advance. At this time, the reflected power is measured by the power monitor detection sections 5a and 5b, and the reflected power is separated (consumed) to the outside of the system by the isolators 4a and 4b. The microwaves transmitted to the generators 8a and 8b turn the processing gas flowing through the generator tubes 9a and 9b into plasma due to their strong magnetic fields. The plasma processing gas is introduced into the processing chamber 1 through the plasma introduction ports 13a and 13b, and is shower-diffused by the shower pipes 14a and 14b. Plasma introduction ports 22a, b, 23a, b
Similarly, plasma generated by distributed microwaves is introduced into the processing chamber 1 and diffused by shower. After the shower-diffused plasma contacts (processes) an object to be processed (not shown), it is exhausted to the outside of the system via exhaust ports 19a, b, 20a, b, 21a, b.

Effects of the invention By distributing microwaves and introducing and irradiating plasma from multiple locations, the plasma concentration in the processing container can be made uniform, making it possible to uniformly process multiple objects with large and complex shapes. Because the number of units can be reduced, capital investment and electricity costs can be halved.

[Brief explanation of drawings]

1 and 2 show an embodiment of an apparatus for carrying out the plasma branching treatment method of the present invention, in which FIG. 1 is a sectional view, FIG. 2 is a side view, and FIG.
(cross-sectional view) and FIG. 3b (side view) are views showing an example of a conventional plasma processing apparatus, and FIG. 4a (cross-sectional view)
4b (side view) is a diagram showing another example of a conventional plasma processing apparatus. 1...Processing container, 2...Microwave oscillator, 3
...Distributor, 4a, b...Isolator, 5a,
b... Power monitor detection unit, 6a, b... Matching box, 7a, b... Waveguide, 8a, b... Plasma generation furnace, 9a, b... Plasma generation tube, 10a,
b, 12a, b... Fluoro connector, 13a,
b, 22a, b, 23a, b...Plasma inlet, 14a, b, 15a, b, 16a, b...Shower tube, 19a, b, 20a, b, 21a, b
……exhaust port.

Claims (1)

[Claims] 1 In a method in which a microwave discharge plasma is generated outside a processing container, the plasma is introduced into the container, and the surface of a workpiece placed in the container is irradiated with the plasma. Distributes the waves into multiple parts using a distributor,
The distributed microwaves are each guided to a plasma generation mechanism consisting of a plasma generation furnace and a plasma generation tube provided in accordance with the number of distributions, and the plasma generated by each of these plasma generation mechanisms is provided in a processing container. A plasma processing method in which plasma is introduced into a processing container through a plurality of plasma introduction ports.