Activated gas generator and activated gas generation method

Abstract

To provide an activated gas generation device that can treat more efficiently, and a method thereof.SOLUTION: An activated gas generation device comprises a plasma generation unit 1 that applies discharge to raw material gas, a plasma control unit 2 that controls the plasma generation unit, a raw material gas heating unit 5 that sets the temperature of the raw material gas to a temperature higher than ordinary temperature, a raw material gas control unit 6 for adjusting the heating temperature in the raw material gas heating unit, and an activated gas ejection unit 3 that ejects the activated gas generated in the plasma generation unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an activated gas generator and an activated gas generation method. In particular, it relates to an activated gas generator that generates an activated gas by exposing a source gas such as nitrogen gas to plasma, and a method thereof.

Background Art

[0002] Conventionally, surface treatment has been performed during the pretreatment of object bonding and painting. In recent years, instead of chemical methods using liquids, a method of introducing polar functional groups onto the object surface using an activated gas generated from plasma has attracted attention.

[0003] Objects to be treated using such an activated gas generated from plasma include plastics, paper, fibers, semiconductor wafers, liquid crystals, films, etc. By irradiating these objects with the activated gas, the hydrophilicity of the object surface can be improved, the adhesion can be enhanced, the printing adhesion can be improved, and furthermore, the removal and cleaning of organic substances adhering to the object surface or the formation of an oxide film on the object surface can be achieved (Patent Document 1).

[0004] In recent years, surface modification of plastic materials has been important, and the application of engineering plastics (engineering plastics) has been increasing. In particular, materials with a low dielectric constant and good weather resistance, called super engineering plastics (super engineering plastics), are being extensively studied for surface treatment in order to be applied to electronic circuit boards. In the manufacturing process of substrates using these engineering plastics and super engineering plastics, from the perspective of short-time treatment, a method of irradiating the activated gas while transporting the target object using a roll-to-roll or conveyor has been studied.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] The problem that this invention aims to solve is to provide an activated gas generator and method that can process gases more efficiently. [Means for solving the problem]

[0007] To solve the above problems, the activated gas generator according to the present invention is characterized by comprising: a plasma generation unit that applies an electrical discharge to a raw material gas; a plasma control unit that controls the plasma generation unit; a raw material gas heating unit that sets the temperature of the raw material gas to a temperature higher than room temperature; a raw material gas control unit for adjusting the heating temperature in the raw material gas heating unit; and an activated gas ejection unit that ejects the activated gas generated in the plasma generation unit.

[0008] The raw material gas control unit is characterized by setting the temperature of the raw material gas to 100°C or higher.

[0009] The raw material gas heating unit and the plasma generation unit are characterized by being housed in the same chamber.

[0010] The raw material gas heating unit and the plasma generation unit are characterized by being electrically connected via the same path.

[0011] The activated gas generation method according to the present invention is characterized in that, when generating plasma by applying an electrical discharge to a raw material gas, the raw material gas is set to a temperature higher than room temperature before generating the plasma.

[0012] The aforementioned raw material gas is characterized by being set to a temperature of 100°C or higher. [Effects of the Invention]

[0013] The activated gas generator and activated gas generation method having the above configuration are characterized by heating the raw material gas. That is, while it is conventionally known that a heated activated gas (a plasma-treated gas) is brought into contact with an object surface rather than an activated gas at room temperature, the present invention goes a step further and is characterized by heating the raw material gas before it is activated, rather than heating it after it has been activated.

[0014] Furthermore, in conventional methods, when the activated gas generated by exposure to plasma is heated, some kind of heating mechanism must be provided between the activated gas generation area and the object to be treated. This not only leads to the problem of the equipment becoming large and complex, but can also be disadvantageous in terms of efficiency, as the activated gas generated may become inactive before reaching the object. This invention heats the raw material gas before exposure to plasma, allowing the heating mechanism to be freely set independently of the treatment area. As a result, the distance between the activated gas area and the object to be treated can be reduced, and the activated gas can be effectively utilized for surface treatment of objects. [Brief explanation of the drawing]

[0015] [Figure 1] The activated gas generator according to the present invention is shown. [Figure 2] This shows the plasma generation unit according to the present invention. [Figure 3] This shows the raw material gas heating section according to the present invention. [Figure 4] The plasma processing apparatus according to the present invention is shown. [Figure 5] This shows the plasma generation unit according to the present invention. [Figure 6] The experimental results demonstrating the effectiveness of the activated gas generator according to the present invention are shown. [Figure 7] The experimental results demonstrating the effectiveness of the activated gas generator according to the present invention are shown. [Figure 8] The experimental results demonstrating the effectiveness of the activated gas generator according to the present invention are shown. [Figure 9] The experimental results demonstrating the effectiveness of the activated gas generator according to the present invention are shown. [Figure 10] Another embodiment of the activation gas generator according to the present invention is shown. [Figure 11] Another embodiment of the activation gas generator according to the present invention is shown.

Embodiments for Carrying Out the Invention

[0016] FIG. 1 shows the overall configuration of the activation gas generator according to the present invention. The activation gas generator includes a plasma generation unit 1 that serves as a region for generating plasma, a plasma control unit 2 that supplies power to the plasma generation unit 1, an activation gas ejection unit 3 that ejects a gas (activation gas) activated by the plasma toward an object to be processed, a source gas supply unit 4 for introducing a source gas for generating plasma, a source gas heating unit 5 for heating the source gas to a predetermined temperature, and a source gas control unit 6 for controlling the flow rate and heating temperature of the source gas. The source gas supply unit 4 is composed of a cylinder of a source gas such as nitrogen gas, a pressure regulator, a flow meter, and the like. The source gas control unit 6 is a mechanism that controls both the source gas supply unit 4 and the source gas heating unit 5 as a whole.

[0017] FIG. 2 shows a schematic configuration of the plasma generation unit 1 shown in FIG. 1. The chamber 10 is entirely composed of a box-shaped casing, and a pair of electrodes 11, 12 are arranged inside it. A supply port 14 for introducing the source gas and an exhaust port 15 for discharging the activation gas are formed in a part of the wall. These electrodes 11, 12 are in a flat plate shape and are composed of a metal material made of, for example, tungsten. A gap 13 is set to a distance suitable for plasma generation. For example, the electrode gap is 1.0 mm, and the size of the flat plate electrode is 20 mm × 20 mm. The pair of electrodes 11, 12 is supplied with power from the plasma control unit 2 shown in FIG. 1. Thereby, plasma is generated in the gap 13, and the source gas is exposed to the plasma to generate an activation gas. The source gas is, for example, nitrogen gas, and for this reason, nitrogen radicals and active species are generated in the activation gas. As will be described later, a source gas (nitrogen gas) heated to a temperature higher than room temperature is introduced from the supply port 14.

[0018] The plasma control unit 2, located outside the chamber 10, not only supplies power to the pair of electrodes 11 and 12, but also controls the amount of power, application time, application timing, and applied voltage frequency. In addition to electrical control, it can also control the amount and timing of raw material gas introduction by controlling the opening and closing amount in conjunction with the supply port 14.

[0019] The discharge port 15 corresponds to the activated gas ejection section shown in Figure 1, but it is not simply an opening. Similar to the supply port 14, it is equipped with a mechanism that allows the plasma control unit 2 to adjust the discharge volume and timing of the activated gas.

[0020] Figure 3 shows a schematic configuration of the raw material gas heating unit 5 shown in Figure 1. The raw material gas heating unit 5 consists of a heating chamber 50 into which the raw material gas is taken in, a gas introduction unit 51 for introducing the raw material gas into the heating chamber 50, a gas outlet 52 for discharging the gas heated in the heating chamber 50, and a heating source 54 located inside the heating chamber 50.

[0021] The heating source 54 can be any suitable device capable of heating a gas, such as a sheathed heater, ceramic heater, induction heater, infrared LED, or halogen lamp, and is controlled by the raw material gas control unit 6 shown in Figure 1. The heating source 51 may be placed in the same space as the raw material gas, or it may be isolated from the space through which the raw material gas flows using a partition member.

[0022] A temperature sensor 53 is installed inside the heating chamber 50, and the temperature value for heating the raw material gas is fed back and controlled. As will be described in detail later, only the raw material gas is heated to a predetermined temperature, and the activated gas is not heated, nor is the temperature of the activated gas detected. If the temperature sensor were to be placed inside the chamber of the plasma generation unit mentioned above, degradation due to the plasma or false detections may occur, but by targeting the raw material gas, temperature detection and feedback control can be performed reliably and easily. However, the temperature sensor is not limited to being placed inside the heating chamber 50, but can also be installed inside the gas outlet 52 or inside the piping that follows it. Common sensors such as thermocouples and thermistors can be used as temperature sensors.

[0023] Here, the raw material gas heating unit 5 is not limited to a configuration with a heating chamber and a heat source inside it, as shown in Figure 3. For example, a gas heater (product name "Clean Hot": Shin-Netsu Kogyo Co., Ltd.) can also be used. This can heat the gas simply by connecting it to the gas flow path, and it has high heating efficiency, allowing the raw material gas to be heated quickly and cleanly.

[0024] Figure 4 shows a processing apparatus using the activated gas generator according to the present invention. The activated gas generator is shown with only the plasma generation unit 1 and the plasma control unit 2. The activated gas P ejected from the plasma generation unit 1 is irradiated onto the object to be processed S. The object to be processed S is a rolled film, which is driven by a transport mechanism 7 in a so-called roll-to-roll manner. The transport mechanism 7 consists of a drive mechanism 71 and a drive control unit 72, and the drive control unit 72 works in conjunction with the plasma control unit 2. The plasma generation unit 1 is entirely covered with a heat-insulating material 16. This is to maintain the temperature of the heated plasma at a constant value.

[0025] Figure 5 shows the structure of the plasma generation unit 1 shown in Figure 4. Electrode 11 consists of a plate-shaped member attached to an insulator 17. The other electrode 12 consists of a block-shaped member, and heated raw material gas flows between the insulator 17 and electrode 12, generating plasma in that region. The reason for using the insulator 17 is to perform a so-called dielectric barrier discharge with a dielectric material interposed, rather than direct discharge between the electrodes, thereby suppressing wear on the electrodes, especially electrode 11.

[0026] Next, Experiment 1 demonstrating the effects of the present invention will be described. Experiment 1 investigates the relationship between the heating temperature of the raw material gas and the processing effect. Specifically, the raw material gas was exposed to plasma to create an activated gas, and this activated gas was irradiated onto a sample, and the water contact angle (wettability) on the sample surface was measured. The temperature of the raw material gas was varied in five patterns: 25°C (room temperature), 50°C, 100°C, 150°C, and 200°C. The sample was polypropylene, the raw material gas was nitrogen gas, the gas flow rate to the raw material gas heating section was 10 liters / minute, the nozzle of the activated gas generator was 40 mm × 0.2 mm, the power supplied to the electrodes of the activated gas generator was 20 W, the distance between the activated gas nozzle and the object to be processed was 7 mm, and the irradiation time was 40 ms.

[0027] Figure 6 shows the results of Experiment 1. The vertical axis represents the water contact angle on the sample surface, and the horizontal axis represents the temperature of the source gas. From the figure, the water contact angle when the source gas temperature is 25°C (room temperature), i.e., unheated, is 80°C (deg), while the water contact angle when the source gas temperature is 50°C is 74°C, when the source gas temperature is 100°C it is 70°C, when the source gas temperature is 150°C it is 67°C, and when the source gas temperature is 200°C it is 69°C. A smaller water contact angle indicates higher processability, so it has been shown that processability can be improved by setting the heating temperature of the source gas higher than room temperature, and in particular, processability is further improved by heating the source gas to 100°C to 200°C.

[0028] Next, we will describe Experiment 2, another experiment demonstrating the effectiveness of the present invention. This experiment examines the cases where the source gas is heated and where the source gas remains at room temperature while the activated gas is heated. Specifically, we conducted experiments in the following cases: when the source gas remains at room temperature (25°C), an activated gas is generated by plasma and irradiated onto the sample (Experiment 2-1); when an activated gas is created by plasma from a source gas heated to 200°C and irradiated onto the sample (Experiment 2-2); and when an activated gas is created from plasma without heating the source gas at room temperature (25°C), and the activated gas is heated to approximately 50°C by a heater on the stage and irradiated onto the sample (Experiment 2-3). For each of these cases, the irradiation time was varied to 0 ms, 6 ms, 15 ms, 30 ms, 60 ms, 150 ms, and 300 ms. An irradiation time of 0 ms represents the contact angle of water before irradiation with the activated gas. Other conditions are the same as in Experiment 1.

[0029] Figure 7 shows the experimental results. The vertical axis represents the water contact angle on the surface of the object being treated, and the horizontal axis represents the irradiation time of the activated gas to the sample. From the figure, for example, focusing on an irradiation time of 150 ms, the water contact angle was 70° or higher in Experiment 2-1, 69° in Experiment 2-3, and 61° in Experiment 2-2. This shows that the processability is improved by heating the source gas, even though all other conditions are the same.

[0030] The above comparison was made at an irradiation time of 150 ms, but the same trend was observed at other irradiation times as well. When comparing at the same irradiation time, the effect appeared in the order of Experiment 2-1, Experiment 2-3, and Experiment 2-2.

[0031] Next, let's consider the case focusing on the water contact angle. For example, when comparing with a water contact angle of 60°, Experiment 2-2 achieved a water contact angle close to 60° with an irradiation time of 150 ms, while Experiment 2-3 reached a value close to 65° at 300 ms, and Experiment 2-1 only achieved a water contact angle of about 68° even at 300 ms, not reaching 60°. In other words, by heating the raw material gas, it is possible to shorten the irradiation time, resulting in the significant effect of shorter processing time. Shorter processing time is a particularly great advantage in roll-to-roll and conveyor systems that process engineering plastics and super engineering plastics.

[0032] Next, Experiment 3, which demonstrates the effects of the present invention, will be described. Experiment 3 examines the gas flow rate from the raw material gas heating section to the plasma generation section. Specifically, the temperature of the raw material gas was set to two patterns: 25°C (room temperature) and 200°C (heated). At each temperature, the water contact angle was measured at two gas flow rates: 10 liters / min and 20 liters / min. In other words, Experiment 3-1 was conducted at a gas temperature of 25°C with a gas flow rate of 10 liters / min, Experiment 3-2 at a gas temperature of 200°C with a gas flow rate of 10 liters / min, Experiment 3-3 at a gas temperature of 25°C with a gas flow rate of 20 liters / min, and Experiment 3-4 at a gas temperature of 200°C with a gas flow rate of 20 liters / min. In addition, the contact angle was measured in each experiment when the irradiation time was 0 ms, 6 ms, 15 ms, 30 ms, 60 ms, 150 ms, and 300 ms. Other experimental conditions were the same as in Experiments 1 and 2.

[0033] Figure 8 shows the experimental results. The vertical axis represents the water contact angle on the sample surface, and the horizontal axis represents the irradiation time, i.e., the time the activated gas is irradiated onto the polypropylene. From the figure, a comparison between Experiment 3-1 and Experiment 3-3, and between Experiment 3-2 and Experiment 3-4 shows that even with the same gas flow rate, the water contact angle is smaller when the source gas temperature is 200°C than when it is 25°C (room temperature). Furthermore, a comparison between Experiment 3-1 and Experiment 3-2, and between Experiment 3-3 and Experiment 3-4 shows that even with the same gas temperature, the water contact angle is lower when the gas flow rate is 20 liters / min than when it is 10 liters / min.

[0034] Here, a higher flow rate means a larger volume of raw material gas to create the plasma, and in a sense, it seems natural that this would improve processing efficiency. However, simply increasing the flow rate often results in the activated gas disappearing before reaching the material being processed, so flow rate is not necessarily the dominant factor in processing efficiency. It is clear that increasing the temperature of the raw material gas is more effective, even at the same flow rate.

[0035] Specifically, when the irradiation time is 150 ms and the source gas temperature is 200°C, the water contact angle is around 60° regardless of whether the flow rate is 10 liters / min or 20 liters / min. In contrast, when the source gas temperature is 25°C, the water contact angle is greater than 70° regardless of whether the flow rate is 10 liters / min or 20 liters / min.

[0036] In this experiment, the reason for selecting gas flow rates of 10 liters / min and 20 liters / min is that, based on Boyle's Law and Charles's Law, the temperature increased almost twofold from 298K (25°C) to 473K (200°C), and therefore the flow rate was set to the same doubling value.

[0037] Next, we will describe Experiment 4, another experiment related to the present invention. Experiment 4 investigates the relationship between the surface temperature of a sample and the heating temperature of the raw material gas. The temperature of the raw material gas affects the temperature of the activated gas, and further affects the surface temperature of the sample. In this experiment, we investigate the relationship with the water contact angle by changing the temperature of the sample. Specifically, polypropylene, which is the sample, was placed on top of a ceramic heater, and the temperature of the sample was changed to 25°C, 50°C, 100°C, and 150°C. The gas flow rate from the raw material gas heating section to the plasma generation section was 10 liters / minute, and the irradiation time of the activated gas was 40 ms. All other conditions were the same as in Experiments 1, 2, and 3.

[0038] Figure 9 shows the experimental results. The vertical axis represents the contact angle of water on the sample surface, and the horizontal axis represents the temperature of the polypropylene sample. From the figure, it can be seen that the contact angle is 80° when the sample temperature is 25°C, 71°C when the sample temperature is 50°C, 82°C when the sample temperature is 100°C, and 86°C when the sample temperature is 150°C. It can be seen that the highest processability is achieved at a sample temperature of 50°C. As can be seen from this experiment, raising the sample temperature unnecessarily high will actually lower the processing performance. In conclusion, there is an optimal temperature in relation to the material, and in particular, for plastic materials, the range of 40°C to 70°C is optimal.

[0039] Thus, in this invention, the optimal temperature of the object to be processed (sample) can be determined in advance, and the conditions for achieving that optimal value can be stored in the raw material gas control unit. In the above experiment, the sample was placed on top of the heating mechanism for convenience, but in this method, considering productivity, the entire sample is heated, and the speed of temperature control at the contact surface with the activated gas (opposite the heating mechanism) is inferior. Alternatively, if the activated gas itself is heated, a heating mechanism would have to be placed in the region between the plasma generation unit and the object to be processed, which not only increases the size of the device but also causes the object to be heated as a whole, not just the surface. For these reasons, heating the raw material gas in this invention is highly effective.

[0040] Furthermore, in order to process the target object in a short time, it is necessary to bring the plasma generation area (plasma generation unit) as close to the target object as possible. This is because the activating gas generated by the plasma must reach the target object before it becomes deactivated. Since this invention does not heat the activating gas, there is no need to provide a heating mechanism or temperature control mechanism downstream of the plasma generation unit, which simplifies the apparatus and allows for efficient irradiation of the target object with the activating gas.

[0041] Irradiation treatment with an activated gas only requires heating the surface of the object to be treated. Therefore, there is no need to heat the entire object or place it in a high-temperature furnace. In this experiment, when the temperature of the gas introduced into the activated gas generator (temperature of the raw material gas) was set to 100°C or higher, more specifically 150±50°C, the surface temperature of the object to be treated was around 50°C, indicating that optimal conditions for treatment were obtained.

[0042] Furthermore, heating the raw material gas can simultaneously provide the following benefits: The volume of the gas expands within the internal space of the plasma generation unit, increasing the ejection velocity of the plasma gas and allowing the activated gas to be delivered to the object being processed in a short time.

[0043] Generally, in plasma processing, it is important to ensure that the activating gas reaches the surface of the object being treated as much as possible to initiate the reaction. Therefore, to increase the amount of activating gas, it is conceivable to widen the plasma irradiation width, i.e., the irradiation area. This can be achieved by arranging multiple plasma generation units in parallel. However, using this method would result in costs nearly double those of the activating gas generator, lead to larger equipment, and create problems with installation space.

[0044] Another approach is to supply a large amount of power to a single plasma generation unit. In this case, one simply needs to increase the power supplied to the plasma discharge device. This can be done by increasing the voltage applied to the electrodes of the plasma generation unit or by increasing the applied frequency. However, in this case, the electrodes of the plasma generation unit will reach extremely high temperatures. If power is applied that reaches temperatures far exceeding those achievable with a heater, problems will arise in the plasma generation mechanism. For example, if a dielectric material is used for the electrodes, the difference in thermal expansion coefficients between the electrodes and the dielectric material will cause strain at the bonding point, leading to malfunctions such as ceramic cracking. Even in plasma discharge devices that do not use dielectric materials, electrode wear will progress at a very rapid rate.

[0045] Furthermore, increasing the discharge length of the plasma generation section (the gap 13 shown in Figure 2) allows for a higher input power. However, this method requires a higher discharge voltage to accommodate the increased discharge length, which imposes design limitations on high voltages. For example, higher applied voltages necessitate ensuring sufficient creepage distance between the electrode holding material and other metal bodies, and also infringe upon design flexibility in terms of larger wires and electrical connections, as well as the configuration of electrical components. Therefore, voltages above a certain level are not advisable.

[0046] Furthermore, one could consider increasing the size of the electrodes in the plasma generation section to increase the total power input while keeping the power density constant. However, this is not necessarily advantageous from the perspective of the lifetime of the activated gas generated by the plasma. This is because the lifetime of the activated gas is only a few microseconds to a few milliseconds, and even if the electrode size is increased, the activated gas initially produced is not maintained, and many components become inactive before reaching the object being processed.

[0047] Figure 10 shows another embodiment of the activated gas generator according to the present invention. In this embodiment, the plasma generation unit and the raw material gas heating unit are housed in the same chamber.

[0048] Inside the chamber 10 are electrodes 11 and 12, which constitute the plasma generation unit. When raw material gas is introduced from the supply port 14 of the chamber 10, the raw material gas is heated to a desired temperature by the heat source 54, which constitutes the raw material gas heating unit. The heated raw material gas generates plasma between the pair of electrodes. This plasma is discharged from the outlet 15. The plasma control unit is located outside the chamber 10, but is not shown in the diagram. The advantage of this structure is that piping connecting the raw material gas heating unit and the plasma generation unit is unnecessary, thereby avoiding wasted heat dissipation in the piping and improving energy efficiency.

[0049] Figure 11 shows another embodiment of the activated gas generator according to the present invention. This embodiment is characterized in that the plasma generation unit and the raw material gas heating unit are electrically configured as the same system.

[0050] Inside the chamber 10 are electrodes 11 and 12, which constitute the plasma generation unit. When raw material gas is introduced from the supply port 14 of the chamber 10, the raw material gas is heated to a desired temperature by the heat source 54, which constitutes the raw material gas heating unit. The heated raw material gas generates plasma between the pair of electrodes. This plasma is discharged from the outlet 15. The plasma control unit is located outside the chamber 10, but is not shown in the diagram.

[0051] Here, the electrical system constituting the heating source 54 and the electrical system constituting the plasma generation unit are connected in series. The advantage of this structure is that, when a heater is used as the raw material gas heating unit, the heat generated by the heater can be transferred to the electrodes of the plasma generation unit, thereby increasing the efficiency of heat utilization. In this embodiment as well, the plasma generation unit and the raw material gas heating unit can be placed in the same chamber, but this is not necessarily the case. They can also be placed individually in the chamber, and the plasma generation unit and the raw material gas heating unit can be electrically configured as the same system.

[0052] The heating source (heater) in the raw material gas heating section may be controlled by monitoring the temperature of the inlet in the plasma generation section and applying PID control to the power input to the heater. Alternatively, a thermocouple may be provided to the heater to perform cascade control or feedback control. Furthermore, the surface temperature of the object being processed can be monitored to control the temperature of the heating source in the raw material gas heating section and thereby control the power input to it.

[0053] The plasma processing apparatus according to the present invention is suitable for processing engineering plastics and super engineering plastics. This is because these require high processing efficiency due to high-speed processing using a roll-to-roll method. However, it is not limited to these, and methods such as processing printed circuit boards and liquid crystal substrates by placing them on a stage can also be applied. [Explanation of Symbols]

[0054] 1. Plasma generation unit 2 Plasma Control Unit 3. Activated gas injection section 4. Raw material gas supply section 5. Raw material gas heating section 6. Raw material gas control unit 10 Chambers 11 electrodes 12 electrodes 13 void 14 supply ports 15 Outlet 50 heating chambers 51 Gas inlet 52 Gas outlet 53 Temperature Sensor 54 Heating source

Claims

1. A plasma generating unit having a first electrode and a second electrode arranged with a gap between them, and generating plasma in the gap, A plasma control unit that supplies power to the first electrode and the second electrode, A raw material gas heating unit that heats the temperature of the raw material gas to be activated to a temperature higher than room temperature, between 100°C and 200°C, A raw material gas control unit for adjusting the heating temperature in the raw material gas heating unit, A supply port for introducing the raw material gas, which has been heated to a temperature higher than room temperature, into the void, The system includes an activated gas ejection unit that ejects an activated gas, which is formed by the raw material gas passing through the aforementioned void, toward a plastic material to be processed. The only gas introduced into the void where the plasma is generated is the source gas. The activated gas generator is characterized in that the raw material gas control unit determines the heating temperature of the raw material gas based on the surface temperature of the object to be treated when the activated gas is irradiated, which has been determined in advance.

2. The activated gas generator according to claim 1, characterized in that the raw material gas control unit determines the heating temperature of the raw material gas so that the temperature of the object to be processed is between 40°C and 70°C.

3. The activated gas generator according to claim 1, characterized in that the raw material gas heating unit and the plasma generation unit are housed in the same chamber.

4. The activated gas generator according to claim 1, characterized in that the raw material gas heating unit and the plasma generation unit are electrically connected via the same path.

5. (a) A step of heating the raw material gas to a temperature higher than room temperature, 100°C to 200°C, Step (b) involves introducing only the raw material gas heated in step (a) into the gap between the first electrode and the second electrode to which power is supplied, Step (c) involves the raw material gas introduced into the void in step (b) passing through the void and being activated to generate an activated gas, The process includes step (d) of spraying the activated gas generated in step (c) toward the object to be treated, which is a plastic material, A method for generating an activated gas, characterized in that the temperature of the raw material gas heated in step (a) is set based on the surface temperature of the object to be treated when irradiated with the activated gas, which has been determined in advance.

6. The method for generating an activated gas according to claim 5, characterized in that step (d) is a step of raising the temperature of the object to be processed to 40°C to 70°C.

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