JP7788758B2 - Plasma processing apparatus and plasma processing method - Google Patents

Description

The present invention relates to an apparatus and method for manufacturing resin products in which a metal layer is formed on the surface of the resin.

Low-dielectric resins are beginning to be used in various circuit boards, such as those with low transmission loss and compatible with millimeter waves or microwaves. Examples of such low-dielectric resins include liquid crystal polymer (LCP) and fluororesins such as polytetrafluoroethylene (PTFE). However, resin materials such as LCP and PTFE have problems with poor adhesion between themselves and with copper, which is used as wiring material. For this reason, known techniques improve the physical adhesion between the resin substrate and copper by chemically roughening the surface of the circuit board substrate or by forming irregularities on the surface of the copper foil that adheres to the substrate.

However, if the surface of a resin substrate is chemically roughened and a metal such as copper is formed on the surface of the substrate, the roughness of the substrate surface will increase the transmission loss of the circuit board. On the other hand, if copper is attached to the surface of the substrate using an adhesive, the adhesive layer itself will cause transmission loss in the circuit board. If copper is formed on the surface of the substrate by plating, sufficient adhesion between the substrate and the copper cannot be obtained. Another possible method is to irradiate the PTFE substrate with atmospheric plasma to activate the surface, replace the fluorine in the PTFE substrate with hydroxyl groups derived from moisture in the air, and then adhere the copper to the surface of the PTFE substrate to obtain a laminate of PTFE substrate and copper.

However, even when irradiating a PTFE substrate with atmospheric plasma, the maximum contact angle of the PTFE substrate with water is approximately 50°. Furthermore, when copper is adhered to the surface of the PTFE substrate, the adhesion between the PTFE substrate and the copper is approximately 0.2 to 0.4 N/mm. This raises the risk of the copper peeling off from the PTFE substrate during the process of creating a copper circuit pattern on the PTFE substrate. Furthermore, if heat is applied to the PTFE substrate during the circuit pattern creation process, the adhesion between the PTFE substrate and the copper will further decrease. Furthermore, because the surface of the PTFE substrate is modified for approximately 24 hours, it is necessary to quickly adhere the copper to the surface of the PTFE substrate, which has been a constraint on the production of circuit boards.

A known technique involves cleaning the surface of a substrate in a vacuum with a high-energy beam, and then irradiating the surface with ionized water vapor to adsorb hydroxyl groups onto the surface of the substrate (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 9-3220

However, because the energy of ionized water vapor is strong, once adsorbed hydroxyl groups are released from the surface of the substrate when other water vapor ions are irradiated onto the surface of the substrate. As a result, in the invention described in Patent Document 1, the contact angle between the surface of the substrate and water is approximately 40°. Furthermore, the invention described in Patent Document 1 has the problem of making it difficult to firmly adhere metal to the surface of a resin component.

This application was made in light of these circumstances, and aims to provide a plasma processing apparatus and plasma processing method that imparts high hydrophilicity to the hydrophobic surface of resin for a long period of time, providing high adhesion between a resin member and a metal layer on the member surface, thereby firmly bonding them together.

In order to solve the above problem, the invention of claim 1 is a plasma processing apparatus that irradiates a surface of a resin present in a chamber with plasma to improve the wettability of the surface of the resin, the plasma processing apparatus comprising: a holding section that holds the resin to be irradiated with the plasma, a holding-side circuit that applies a holding-side voltage to the held resin; a gas inlet section that introduces gas into the chamber; and a plasma irradiation device that converts the gas into plasma, the plasma-side circuit being configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device , the plasma processing apparatus comprising: a first step in which the resin is irradiated with plasma by the plasma-side circuit to separate at least some of the atoms that constitute the resin; The method is configured to perform a second step of imparting hydroxyl groups to the resin from which at least some of the atoms have been released in the first step, and a second step of imparting hydroxyl groups to the resin from which at least some of the atoms have been released in the first step, wherein the time for which the holding-side circuit applies the holding-side voltage to the resin and the time for which the plasma-side circuit applies the plasma-side voltage to the plasma irradiation device are set to be separate, and the plasma-side circuit is equipped with an application time adjustment unit for setting the time for which the plasma-side circuit applies the plasma-side voltage to be shorter than the time for which the holding-side voltage is applied to the holding-side circuit, until the resin from which at least some of the atoms constituting the resin have been released in the first step reaches a state in which hydroxyl groups have been imparted in the second step.

The invention described in claim 2 is a plasma processing apparatus that irradiates a surface of a resin present in a chamber with plasma to improve the wettability of the surface of the resin, the plasma processing apparatus comprising: a holding section that holds the resin to be irradiated with the plasma, a holding-side circuit that applies a holding-side voltage to the held resin; a gas inlet section that introduces gas into the chamber; and a plasma irradiation device that converts the gas into plasma, the plasma-side circuit being configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device. The plasma processing apparatus comprises: a first step in which the resin is irradiated with plasma by the plasma-side circuit to remove at least some of the atoms that make up the resin; and a second step in which the resin from which at least some of the atoms have been removed in the first step is subjected to a second plasma treatment. and a second step of imparting hydroxyl groups to the plasma irradiation device, and the plasma-side circuit and the holding-side circuit are characterized in that they include: a first voltage application unit that turns on the plasma-side circuit to apply the plasma-side voltage to the plasma irradiation device and turns off the holding-side circuit in the first step; a second voltage application unit that turns off the plasma-side circuit and turns on the holding-side circuit to apply the holding-side voltage to the holding unit during the period from the end of the first step to the start of the second step; and a third voltage application unit that turns on the plasma-side circuit to apply the plasma-side voltage to the plasma irradiation device and turns on the holding-side circuit to apply the holding-side voltage to the holding unit in the second step .

The invention described in claim 3 is characterized in that, in addition to the configuration described in claim 1 or 2 , the plasma side circuit and the holding side circuit are configured so that the time for applying the holding side voltage and the time for applying the plasma side voltage are separate in order to perform the second step of imparting hydroxyl groups to the resin that has undergone the first step.

The invention of claim 4 is a plasma processing method comprising: a chamber for accommodating a resin to be irradiated with plasma; a holding-side circuit having a holding part for holding the resin to be irradiated with plasma and applying a holding-side voltage to the held resin; a gas inlet part for introducing gas into the chamber; and a plasma irradiation device for converting the gas into plasma, the plasma-side circuit being configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device, the method irradiating plasma onto a surface of the resin present in the chamber to improve wettability of the surface of the resin, the plasma processing method comprising: a first step of irradiating the resin with plasma by the plasma-side circuit to separate at least some of the atoms constituting the resin; The plasma irradiation device is configured so that a first step is performed, and a second step is performed to impart hydroxyl groups to the resin from which the atoms have been released , and the time for which the holding-side circuit applies the holding-side voltage to the resin and the time for which the plasma-side circuit applies the plasma-side voltage to the plasma irradiation device are set to be separate, and an application time adjustment unit provided in the plasma-side circuit for adjusting the time for which the plasma-side circuit applies the plasma-side voltage is set so that the time for which the plasma-side circuit applies the plasma-side voltage is shorter than the time for which the holding-side voltage is applied to the holding-side circuit, until the resin from which at least some of the atoms constituting the resin have been released after the first step is imparted with hydroxyl groups in the second step.

The invention of claim 5 is a plasma processing method for improving the wettability of a surface of a resin present in a chamber by irradiating the surface of the resin with plasma, wherein a plasma processing apparatus for performing the plasma processing method has a holding part for holding the resin to be irradiated with the plasma, and is equipped with a holding-side circuit for applying a holding-side voltage as a DC voltage to the held resin, a gas inlet part for introducing gas into the chamber, and a plasma irradiation device for converting the gas into plasma, and a plasma-side circuit configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device, and the plasma processing apparatus includes: a first step in which the resin is irradiated with plasma by the plasma-side circuit to thereby remove at least some of the atoms constituting the resin; and a second step in which at least some of the atoms are removed in the first step. and a second step of imparting hydroxyl groups to the released resin, wherein the plasma-side circuit and the holding-side circuit perform a first voltage application step in which, in the first step, the plasma-side circuit is turned on and the plasma-side voltage is applied to the plasma irradiation device while the holding-side circuit is turned off; a second voltage application step in which, from the end of the first step until the start of the second step, the plasma-side circuit is turned off and the holding-side circuit is turned on and the holding-side voltage is applied to the holding unit; and a third voltage application step in which, in the second step, the plasma-side circuit is turned on and the plasma-side voltage is applied to the plasma irradiation device while the holding-side circuit is turned on and the holding-side voltage is applied to the holding unit .

According to the inventions of claims 1 , 2, 4, and 5 , the holding circuit applies a holding voltage as a DC voltage to the resin to be irradiated with plasma, and the time for applying the holding voltage to impart hydroxyl groups to the resin held in the holding section is set separately from the time for applying the plasma voltage as a DC voltage to the plasma irradiation device, which converts the gas introduced by the gas inlet into plasma, to the plasma irradiation device. This allows for free adjustment of the timing at which the plasma irradiation device generates ions and radicals to irradiate the resin held in the holding section with the ions and radicals, as well as the state of the potential around the holding section and the resin held in the holding section, and thus allows for free adjustment of the timing and state at which the ions and radicals act on the resin while it is contained in the chamber. This allows for free adjustment of the timing at which the ions and radicals act on the resin while it is contained in the chamber. This allows for free adjustment of the radicals to be imparted to the resin surface in an optimal state, providing high adhesion between the resin member and the metal layer on the member surface and firmly bonding them.

According to the inventions of claims 1 and 4 , the application time adjustment unit of the plasma side circuit is set so that the time during which the plasma side circuit applies the plasma side voltage to the holding unit is shorter than the time during which the holding unit applies the holding side voltage to the holding unit during the first process, from when at least some of the atoms constituting the resin have been released to when hydroxyl groups are added in the second process . This allows a potential difference to be generated between the area around the resin held in the holding unit and the area in the chamber other than the area around the resin, even before the plasma irradiation process using the plasma irradiation device. This makes it possible to easily control the distribution of ions and radicals in the chamber to create an environment conducive to plasma generation in the plasma irradiation device. Furthermore, even after the plasma irradiation process, radicals generated by discharge due to application of the holding side voltage are present in the holding unit, allowing for the addition of hydroxyl groups to be steadily carried out. This allows various radicals to be added to the resin surface in an optimal state, providing high adhesion between the resin component and the metal layer on the component surface and firmly bonding them.

According to the inventions of claims 2 and 5 , the plasma processing apparatus is configured to perform at least a first step in which the resin is irradiated with plasma by the plasma side circuit to remove at least some of the atoms constituting the resin, and a second step in which hydroxyl groups are added to the resin from which at least some of the atoms have been removed in the first step. The plasma side circuit and the holding side circuit are configured such that, in the first step, the plasma side circuit is turned on to apply a plasma side voltage to the plasma irradiation device and the holding side circuit is turned off. Then, from the end of the first step until the start of the second step, the plasma side circuit is turned off and the holding side circuit is turned on to apply a holding side voltage to the holding unit. Then, in the second step, the plasma side circuit is turned on to apply a plasma side voltage to the plasma irradiation device and the holding side circuit is turned on to apply a holding side voltage to the holding unit. Even before the plasma irradiation step by the plasma irradiation device, a potential difference is generated between the periphery of the resin held in the holding unit and the area in the chamber other than the periphery of the resin, thereby easily controlling the distribution of ions and radicals in the chamber to create an environment conducive to plasma generation in the plasma irradiation device. Furthermore, even after the plasma irradiation process, radicals generated by the discharge generated by applying the holding voltage remain on the holding part, allowing the addition of hydroxyl groups to be steadily carried out. This allows various radicals to be added to the resin surface in an optimal state, providing high adhesion between the resin component and the metal layer on the component surface and firmly bonding them together.

According to the invention of claim 3 , in the process of imparting hydroxyl groups to resin in a state in which at least some of the atoms constituting the resin are released by irradiating the resin with plasma from the plasma side circuit, the timing and state in which ions or radicals act on the resin can be freely adjusted, thereby imparting radicals to the resin surface in an appropriate state, providing high adhesion between the resin member and the metal layer on the member surface and firmly bonding them.

1A and 1B are diagrams showing a schematic side view and a schematic top view of a substrate manufacturing system in which a plasma processing apparatus according to this embodiment is used; FIG. 2 is a diagram schematically illustrating the plasma processing apparatus. 3 is a flowchart of processing steps in the substrate manufacturing system. 4 is a diagram showing a schematic diagram of the state during plasma generation in the second step in the plasma processing apparatus of FIG. 10 is a diagram showing a state after plasma generation in the second step in the plasma processing apparatus shown in FIG.

Figures 1 to 5 show this embodiment.

[Configuration of circuit board manufacturing system]
1A and 1B are diagrams showing a schematic view of a substrate manufacturing system in which a plasma processing apparatus according to this embodiment is used, in which (a) is a schematic view seen from the side, and (b) is a schematic view seen from above.

This board manufacturing system 100 is a manufacturing system consisting of multiple devices for performing multiple manufacturing processes to manufacture circuit boards with low transmission loss that are compatible with, for example, millimeter waves or microwaves. The board 21 manufactured in the board manufacturing system 100 has a metal layer such as a metal film 23 formed on the front and back surfaces of a resin board body 22, which is the workpiece.

As shown in FIG. 1, in the substrate manufacturing system 100, the processed member is a substrate body 22 made of a sheet-like piece of resin. During the manufacturing process in the substrate manufacturing system 100, a metal layer such as a metal film 23 is formed on the surface of this substrate body 22 to form a substrate 21. The substrate manufacturing system 100 includes vacuum reserve chambers 101 and 102, a first processing chamber 103 for performing the first step S1 and the second step S2 (both described below), a second processing chamber 104 for performing the third step S3 (described below), and gate valves 24, 24, 25, 26, 27, and 28. The first processing chamber 103 includes a pair of vacuum chambers 2. The vacuum chamber 2 on one side (left side of FIG. 1) constitutes a processing chamber for processing the front side of the substrate body 22, and the vacuum chamber 2 on the other side (right side of FIG. 1) constitutes a processing chamber for processing the back side of the substrate body 22. In this embodiment, the processing performed on the front and back sides of the substrate body 22 and the processing steps for those processing steps are the same. Therefore, the vacuum chamber 2 on one side and the vacuum chamber 2 on the other side have the same configuration and are arranged symmetrically from top to bottom.

In the second processing chamber 104, the front surface processing chamber 105 on one side (left side in Figure 1) and the back surface processing chamber 106 on the other side (right side in Figure 1) are used to perform the same processing on the front and back surfaces of the substrate body 22, and are identically configured and symmetrically arranged vertically. Figure 1 shows that heaters 29 for the CVD method are arranged symmetrically vertically in each of the front surface processing chamber 105 and back surface processing chamber 106. Instead of the heaters 29, a sputtering device (not shown) used for the PVD method (sputtering method) may be provided.

1, the vacuum preparatory chamber 101 is provided with a movable part 31 that holds the substrate body 22 at its ends and a track part 32a that transports the movable part 31. Similarly, the first processing chamber 103, the second processing chamber 104, and the vacuum preparatory chamber 102 are provided with track parts 32b, 32c, 32d, 32e, and 32f that transport the movable part 31 that holds the substrate body 22. The method of transporting the substrate body 22 by the movable part 31 and the track parts 32a, 32b, 32c, 32d, 32e, and 32f shown in FIG. 1 is, for example, a linear guide method or a rack-and-pinion method.
In the fourth step S4 (described later), the substrate body 22 is removed from the substrate manufacturing system 100, and the surface of the substrate body 22 is plated with metal or a metal foil of the same thickness as the plating is laminated offline (not shown) to form a metal layer such as a metal film 23 required for the circuit board.

[Configuration of Plasma Processing Apparatus]
2 is a diagram showing a schematic view of the plasma processing apparatus of this embodiment, which shows a first step S1 described later.

The plasma processing apparatus 1 shown in Figure 2 constitutes the first processing chamber 103 shown in Figure 1. This plasma processing apparatus 1 irradiates the surface of the resin with plasma to remove at least some of the atoms that make up the resin, and then adds hydroxyl groups to the resin, improving the wettability of the resin surface. Improved wettability makes it possible to strengthen the bond when bonding a metal layer, such as a metal film 23, to the resin surface.

Note that, for simplicity of explanation, Figure 2 only describes the configuration of the vacuum chamber 2 on one side (the left side in Figure 1) of the first processing chamber 103 shown in Figure 1. For simplicity of explanation, the following description will only describe the vacuum chamber 2 on one side shown in Figure 2, unless a particular distinction is required, and will omit a description of the vacuum chamber 2 on the other side (the right side in Figure 1) that processes the back side of the substrate body 22.

The plasma processing apparatus 1 of this embodiment shown in Figure 2 includes a vacuum chamber 2, a fine plasma gun (FPG) 3, a holding table 4 serving as a "holding unit," a cover 5, a holding-side power supply 8, a plasma-side power supply 9, a holding-side switch 11, and a plasma-side switch 12.

The holding-side power supply 8, holding table 4, and vacuum chamber 2 form a holding-side circuit 13. The plasma-side power supply 9, plasma-side switch 12, FPG 3, and vacuum chamber 2 form a plasma-side circuit 14. The plasma processing apparatus 1 also includes a gas inlet 15 and an exhaust section 17 with an exhaust pump 16.

Note that Figure 2 schematically shows the directions in which ions 7 and radicals 6 fly inside the vacuum chamber 2. This is also true for Figure 4, which will be described later. As will be described later, the radicals 6 in this embodiment are hydroxyl radicals. However, the radicals 6 may be any radicals other than hydroxyl radicals.

The vacuum chamber 2 is made of a highly rigid metal such as aluminum alloy or stainless steel. The vacuum chamber 2 is strong enough to withstand the pressure difference between the inside and outside caused by the exhaust pump 16, and has a box-shaped processing space formed inside. The processing space of the vacuum chamber 2 is designed to create a vacuum when the gas inside is forcibly exhausted to the outside by the exhaust pump 16. The vacuum chamber 2 is also connected to the ground 10. This ground 10 sets the reference potential for the holding side circuit 13 and the plasma side circuit 14.

The FPG 3 is located at the top of the vacuum chamber 2. The FPG 3 converts the process gas introduced into the vacuum chamber 2 from the gas inlet 15 into plasma. The FPG 3 may be, for example, the one described in WO 2014/175702.

As shown in Figure 1, FPGA 3 has a first FPGA 3a and a second FPGA 3b.

The first FPG 3a is configured to rotate about a rotation axis (not shown) so as to change the plasma irradiation direction along the transport direction of the substrate body 22 (the left-right direction in FIG. 1). The first FPG 3a is used in the first step S1, which will be described later.

The second FPG 3b does not have a rotation axis and irradiates plasma in only one direction. The second FPG 3b is used in the second step S2, which will be described later.

The second FPG 3b may have a rotation axis (not shown) and be configured to change the direction of plasma irradiation in the transport direction of the substrate body 22, or the first FPG 3a may not have a rotation axis (not shown) and be configured to irradiate plasma in only one direction.

The holder 4 is installed below the FPG 3 so as to face the FPG 3. The holder 4 is made of metal or an electrode, and holds the substrate body 22.

In this embodiment, the holding table 4 receives a holding-side voltage (described below) from the holding-side power supply 8 in the second step S2 described below.

In the first step S1 and the second step S2, the holding table 4 receives a holding-side voltage (described below) from the holding-side power supply 8 at least to a portion of the holding table 4 that depends on the position of the substrate body 22. For example, in the second step S2, the holding-side voltage may be applied to the side of the holding table 4 near the second FPG 3b (the right side in FIG. 1). To apply the holding-side voltage in this manner, the holding table 4 may be configured to apply the holding-side voltage to only a portion of the holding table 4. For example, the holding table 4 may be configured to have a first conductive range (not shown) near the first FPG 3a and a second conductive range (not shown) near the second FPG 3b, and may be provided with a switch (not shown) that switches the current from the holding-side power supply 8 between the first conductive range (not shown) and the second conductive range (not shown). However, any other configuration may be used to switch or change the position or range of the holding table 4 to which the holding-side voltage is applied.

The position and range at which the holding-side voltage is applied to the holding table 4 in the first step S1 and the second step S2 may be any. Furthermore, the holding-side voltage may be applied to the entire holding table 4 in both the first step S1 and the second step S2.

The cover 5 covers the top surface of the holder 4. The cover 5 is made of the same material as the substrate body 22. It is configured so that plasma from the FPG 3 is uniformly irradiated onto the substrate body 22. Without the cover 5, the plasma emitted from the FPG 3 would also be irradiated onto the metal holder 4, processing the metal portion, and the particles removed would adhere to and contaminate the substrate body 22. The cover 5 is necessary to prevent this contamination. Note that if the impact of particles is small, omitting the cover 5 will not affect the present invention.

The holding-side power supply 8 is a DC power supply. The positive electrode of the holding-side power supply 8 is connected to the holding table 4, and the negative electrode is connected to the vacuum chamber 2, and applies a holding-side voltage, which is a DC voltage, to the holding-side circuit 13.

The plasma-side power supply 9 is a DC power supply. The positive electrode of the plasma-side power supply 9 is connected to the holding table 4 side, and the negative electrode is connected to the vacuum chamber 2 side, and applies a plasma-side voltage, which is a DC voltage, to the plasma-side circuit 14. In order to emit plasma from the FPG 3, it is desirable that the plasma-side power supply 9 have a higher output than the holding-side power supply 8 and be able to apply a higher voltage to the plasma-side circuit 14 than the holding-side power supply 8.

The holding-side switch 11 and plasma-side switch 12 are switches that switch the current flowing through the circuits between ON and OFF. The holding-side switch 11 switches the current flowing through the holding-side circuit 13 ON and OFF, and the plasma-side switch 12 switches the current flowing through the plasma-side circuit 14 ON and OFF.

The holding-side switch 11 is selectively connected to the energized conductor 18 and the non-energized conductor 19. The energized conductor 18 is electrically connected to the holding-side power supply 8, and when the holding-side switch 11 is connected, the holding-side circuit 13 is turned ON, applying the voltage of the holding-side power supply 8 to the holding base 4. The non-energized conductor 19 is electrically connected to the holding base 4 without passing through the holding-side power supply 8, and when the holding-side switch 11 is connected, the holding-side circuit 13 is turned OFF, and the potential of the holding base 4 becomes equal to the potential of ground 10.

The holding-side switch 11 and the plasma-side switch 12 may be configured to adjust the flow rate of current through the circuit from 0 to maximum in a stepwise or stepless manner. The holding-side switch 11 and the plasma-side switch 12 may be configured to be switched ON/OFF by a control device such as a microcomputer (not shown), or may be configured to be switched ON/OFF manually by an operator.

The gas inlet 15 is a metal pipe that introduces gases used in the first step S1 and second step S2, described below, into the vacuum chamber 2.

The exhaust section 17 is a metal pipe with an exhaust pump 16 installed midway through. When the exhaust pump 16 is activated, the exhaust section 17 expels various gases, particles, dust, etc. present within the vacuum chamber 2 to the outside.

[Board body]
In this embodiment, the resin constituting the substrate body 22 is not particularly limited as long as it has a hydrophobic surface, but examples include fluororesins such as PTFE, PFA, and PCTFE, polyimide, and LCP. Specifically, in the case of fluororesins, the resin used as the material for the substrate body 22 contains fluorine and carbon, and the atoms that desorb from the hydrophobic surface of the resin are primarily fluorine and carbon. By breaking molecular bonds and adding hydroxyl groups to the activated surface, the hydrophobic surface of the fluororesin can be significantly hydrophilized. Furthermore, this phenomenon occurs only on the resin surface; the underlying fluorine-containing resin base material has high insulation properties, small dielectric constant and dielectric loss tangent, and low signal transmission loss, making it an excellent electrical substrate.

In addition to the above materials, the resin used as the material for the substrate body 22 may also contain wholly aromatic polyester, and the atom that desorbs from the hydrophobic surface of the resin may be oxygen.

[plasma]
In this embodiment, the plasma generated from the FPG 3 preferably contains at least one of nitrogen and argon. A mixed gas of nitrogen and argon is also acceptable. This is because atoms constituting the resin used as the material for the substrate body 22 are likely to be desorbed from the surface of the resin by ions of nitrogen or argon.

[Processing process]
3 is a flowchart of the processing steps in substrate manufacturing system 100 of this embodiment. The substrate manufacturing steps of this embodiment will be described below using this flowchart.

[First step]
In the substrate manufacturing system 100, first, in the first step (step S1, hereinafter referred to as "first step S1"), ions are irradiated onto the surface of the substrate body 22, which is the member to be processed, thereby breaking the molecular bonds on the substrate surface and causing at least some of the atoms of the resin that makes up the substrate to be detached.

Prior to the first step S1, the gate valve 24 shown in FIG. 1 is opened, and the movable part 31 holding the end of the substrate body 22 is attached to the track part 32a inside the vacuum reserve chamber 101. The gate valve 24 is closed, and the pressure inside the vacuum reserve chamber 101 is reduced. When the pressure inside the vacuum reserve chamber 101 falls to 10 Pa or less, the gate valve 25 is opened.

After opening the gate valve 25, the movable part 31 is moved into the vacuum chamber 2 of the first processing chamber 103, and the gate valve 25 is closed. At this time, the holding-side switch 11 and the plasma-side switch 12 are both OFF, and neither the holding-side circuit 13 nor the plasma-side circuit 14 is energized. As mentioned above, when the holding-side switch 11 is OFF, the holding-side switch 11 is connected to the non-energized-side conductor 19, and the potential of the holding table 4 is equal to the potential of the ground 10.

In the first step S1, plasma from the first FPG 3a is irradiated onto the hydrophobic surface (upper surface side in Figure 1a) of the substrate body 22, causing at least some of the atoms of the resin that constitutes the substrate body 22 to be desorbed from the surface of the substrate body 22. That is, in the first step S1, the hydrophobic surface of the substrate body 22 is activated by using plasma, particularly ions in the plasma, to activate the surface of the resin that constitutes the substrate body 22.

Specifically, while the pressure inside the vacuum chamber 2 is reduced using the exhaust pump 16, nitrogen and argon process gases are introduced into the vacuum chamber 2 through the gas inlet 15, and the pressure inside the vacuum chamber 2 is adjusted to a predetermined level, for example, 0.3 Pa, in the range of 0.1 Pa to 0.4 Pa.

In this state, as shown in FIG. 2, when the plasma-side switch 12 is turned on and the plasma-side circuit 14 is energized, a second DC voltage is applied from the plasma-side power supply 9 to the first FPG 3a, and plasma of the processing gas is generated in the first FPG 3a. The second FPG 3b is used in the second step S2 described below, so it is not energized and no plasma is generated in this step.

If the pressure inside the vacuum chamber 2 is too high (for example, above 0.4 Pa), the processing gas will enter a glow discharge state, making it impossible to control the direction of travel of the ions 7 and radicals 6 in the plasma. In contrast, if the pressure inside the vacuum chamber 2 is within an appropriate range, the processing gas will maintain a dark discharge state, and the direction of travel of the ions 7 and radicals 6 can be controlled. Therefore, the pressure inside the vacuum chamber 2 is adjusted to, for example, between 0.1 Pa and 0.4 Pa. It is preferable that the pressure inside the vacuum chamber 2 be around 0.3 Pa.

The first FPG 3a generates plasma from the processing gas filled in the vacuum chamber 2, and as shown in Figure 2, these become directional ions and radicals that are irradiated onto the substrate body 22. At this time, the ions generated have positive polarity, and the radicals are non-polar.

As shown in FIG. 2, the generated ions 7 and radicals 6 collide with the substrate body 22, and atoms of the resin that makes up the substrate body 22 are detached from the surface of the substrate body 22, mainly due to the impact of the collisions of the ions 7. Most of the detached atoms are exhausted from the vacuum chamber 2 through the exhaust section 17 by the exhaust pump 16. Some of the detached atoms float within the vacuum chamber 2, or after floating, adhere to the inner wall of the vacuum chamber 2 or components within the vacuum chamber 2. However, in this embodiment, the pressure within the vacuum chamber 2 is lower than the general glow discharge conditions, so there are almost no impurities (such as particles) floating within the chamber 2. This prevents impurities from adhering to the surface of the substrate body 2 and contaminating it.

[End of first process]
When the first step S1 is to be completed, the plasma-side switch 12 is turned OFF to de-energize the plasma-side circuit 14. This terminates the generation of plasma from the processing gas by the first FPG 3a.

[Power supply state after completion of first process]
Between the end of the first step S1 and the start of the second step S2 (described later), the holding-side switch 11 is connected to the current-carrying conductor 18 and turned ON, thereby energizing the holding-side circuit 13. As a result, a holding-side voltage from the holding-side power supply 8 is applied to the holding table 4 and the substrate body 22 on the holding table 4. The holding-side voltage is applied to a first conductive range (not shown) near the first FPGA 3a. At this time, it is desirable for the holding-side power supply 8 to apply to the holding-side circuit 13 a voltage that is at least 40% of the voltage of the plasma-side power supply 9 but is smaller than the voltage of the plasma-side power supply 9.

A positive voltage is applied as a holding-side voltage to the holding table 4 and the substrate body 22 on the holding table 4, which constitute the holding-side circuit 13. Meanwhile, the wall surface of the vacuum chamber 2, which constitutes the holding-side circuit 13, is at a lower potential than the holding table 4 and the substrate body 22. The first FPG 3a is on the positive side, and the opposing holding table 4 is also on the positive side. Because the voltages of the two are close, plasma generation in the first FPG 3a is unlikely to occur. By applying a holding-side voltage from the holding-side power supply 8 between the end of the first step S1 and the start of the second step S2, described below, it is possible to create an environment that is conducive to plasma generation in the first FPG 3a.

[Second process]
When a second step (step S2, hereinafter referred to as "second step S2") is performed in the vacuum chamber 2 after the first step S1, the following procedure is followed.

In this embodiment, the first step S1 and the second step S2 are performed in the same vacuum chamber 2, thereby simplifying the processing steps and miniaturizing the equipment. However, the vacuum chamber 2 for performing the first step S1 and the vacuum chamber (not shown) for performing the second step S2 may be provided separately. Providing the vacuum chamber 2 for performing the first step S1 and the vacuum chamber (not shown) for performing the second step S2 separately has the effect of easily preventing a situation in which desorbed components desorbed from the surface of the substrate body 22 in the first step S1 are floating in the vacuum chamber 2 and those desorbed components adhere to the surface of the substrate body 22 in the second step S2.

In this embodiment, after the first step S1, the exhaust pump 16 appropriately removes desorbed components from the vacuum chamber 2, thereby preventing floating matter from the first step S1 from affecting the second step S2.

After the first step S1 is completed, the substrate body 22 is maintained in a state where it is held on the holding table 4 within the vacuum chamber 2.

Next, the exhaust pump 16 continues to operate, maintaining the reduced pressure inside the vacuum chamber 2. When the supply of nitrogen and/or argon used in the first step S1, which is present inside the vacuum chamber 2, is stopped, and is immediately discharged outside the vacuum chamber 2 by the exhaust pump 16. Then, while introducing water vapor, the process gas, into the vacuum chamber 2 through the gas inlet 15, the exhaust pump 16 is controlled to adjust the pressure inside the vacuum chamber 2 in the second step S2 so that the pressure inside the vacuum chamber 2 is 30% to 50% of the pressure in the first step S1. This is because performing the second step S2 process described below at a pressure of 30% to 50% of the pressure in the first step S1 allows radicals 6 (hydroxyl radicals) in the plasma of the process gas to optimally adhere to the surface.

After the process gas is introduced into the vacuum chamber 2, as shown in FIG. 4, the holding-side switch 11 is switched from its non-conductive side conductor 19 to its conductive side conductor 18, turning on the holding-side circuit 13 and applying the voltage of the holding-side power supply 8 to the holding table 4. The holding-side voltage is applied to a second conductive range (not shown) near the second FPG 3b. Note that the process gas may be introduced into the vacuum chamber 2 after or simultaneously with turning on the holding-side circuit 13. Next, the plasma-side circuit 14 is turned on, and electricity is applied from the plasma-side power supply 9 to the FPG 3. As shown in FIG. 1, the application of the plasma-side voltage to the second FPG 3b activates the second FPG 3b, generating plasma of the process gas filled in the vacuum chamber 2.

At this time, it is preferable that the first DC voltage applied to the holding table 4 from the holding-side power supply 8 be smaller than the second DC voltage applied to the second FPG 3b from the plasma-side power supply 9. Specifically, it is even more preferable that the first DC voltage from the holding-side power supply 8 be 40% or more of the second DC voltage applied to the second FPG 3b from the plasma-side power supply 9, and smaller than the second DC voltage.

The holding-side power supply 8 applies a positive voltage to the holding table 4 and the substrate body 22, and the plasma-side power supply 9 applies a positive voltage to the second FPG 3b. The potentials of the second FPG 3b and the holding table 4 are both positive, while the potential of the vacuum chamber 2 (which forms the plasma-side circuit 14 and the holding-side circuit 13) relative to the second FPG 3b and the holding table 4 is negative. Furthermore, while the potential difference between the second FPG 3b and the holding table 4 decreases, the potential differences between the FPG 3 and the vacuum chamber 2, and between the holding table 4 and the vacuum chamber 2 increase.

In this state, when plasma is generated in the process gas in the vacuum chamber 2 by the second FPG 3b, as shown in Figure 5, most of the positive ions 7 in the plasma move toward the vacuum chamber 2, where the potential difference is greater. Meanwhile, non-polar radicals 6 (hydroxyl radicals) in the plasma are irradiated onto the substrate body 22.

By irradiating the substrate body 22 with radicals 6 (hydroxyl radicals), hydroxyl groups are introduced onto the surface of the substrate body 22. Furthermore, since the ions 7 move toward the wall of the vacuum chamber 2 and the substrate body 22 is hardly irradiated with ions 7, the hydroxyl groups introduced onto the surface of the substrate body 22 by the impact of the ions are prevented from detaching again. In this way, stable hydrophilicity is imparted to the surface of the substrate body 22. The introduction of hydroxyl groups results in stable chemical bonding between the hydroxyl groups and the surface of the substrate body 22. The amount of bonding increases with irradiation time until no reactive groups remain. As the number of hydroxyl groups increases, the contact angle decreases.

The surface of the substrate body 22, onto which hydroxyl groups have been introduced in the second step S2, should preferably have a contact angle with water of 10° or less, more preferably 6° or less, and an appropriate irradiation time should be set. This ensures strong adhesion between the surface of the substrate body 22 and the metal film 23 in the third step S3 and fourth step S4 described below.

[Pressure and temperature in the first and second steps]
It is preferable that both the first and second steps be performed with the inside of the vacuum chamber 2 under reduced pressure. Furthermore, it is preferable that the second step be performed after the first step while maintaining the reduced pressure. This is because hydroxyl groups can be introduced into the surface of the resin that constitutes the substrate body 22 while maintaining the activated state of the surface of the resin that constitutes the substrate body 30 in the first step. The hydrophilicity of the resin surface that has undergone the second step is maintained for a long period of time, for example, for one month or more. Therefore, the substrate body 22 may be released to atmospheric pressure immediately after the second step.

The first step S1 is preferably carried out at a first pressure of 0.1 Pa or more and 0.4 Pa or less, and the second step S2 is preferably carried out at a second pressure of 30% or more and 50% or less of the first pressure. This is because in the first step S1, it is easy to control the way in which ions and radicals in the plasma travel, and in the second step, ions are hardly irradiated onto the surface of the substrate body 22, and hydroxyl radicals are more likely to irradiate onto the surface of the substrate body 22.

The second step S2 is preferably performed at a temperature of the substrate body 22 of 150°C or higher and 300°C or lower. This is because the chemical reaction between the hydroxyl groups and the surface of the resin that makes up the substrate body 22 is accelerated, and the hydroxyl groups are firmly incorporated into the surface that makes up the substrate body 22.

[Electrification state after second process]
In the second step S2, even after the plasma-side power supply 9 is turned OFF and the application of the second DC voltage to the second FPG 3b is stopped, it is desirable to keep the holding-side switch 11 connected to the current-carrying conductor 18 and the holding-side circuit 13 ON, as shown in FIG. 5 . When the holding-side circuit 13 is turned ON, a positive voltage is applied from the holding-side power supply 8 to the holding table 4 and the substrate body 22, resulting in a positive potential on the holding table 4 side of the holding-side circuit 13 and a negative potential on the vacuum chamber 2 side. This causes positive ions in the vacuum chamber 2 to be attracted to the wall surface of the vacuum chamber 2, where the potential difference is greater. This prevents hydroxyl groups introduced onto the surface of the substrate body 22 by ion impact from being desorbed again, even after the plasma-side power supply 9 is turned OFF. Furthermore, by applying a positive voltage from the holding-side power supply 8 to the holding table 4 and the substrate body 22, any remaining hydroxyl groups can be attached by the slight glow discharge generated at the holding table 4.

In the second step S2, the length of time for which the holding-side circuit 13 is kept ON after the plasma-side power supply 9 is turned OFF may be any length. Specifically, it may be any length of time as long as the time for which the holding-side power supply 8 applies the holding-side voltage to the holder 4 and the substrate body 22 is longer than the time for which the plasma-side power supply 9 applies the plasma-side voltage to the right-side FPG 3, and the progress of detachment from the surface of the substrate body 22 due to ions can be prevented.
For ease of understanding, the present description uses a first FPG 3a for the first step S1 and a right-side FPG 3 for the second step S2. However, a second FPG 3b may also be used for the first step S1. In this case, it is desirable that the plasmas generated by the first FPG 3a and the second FPG 3b are oriented parallel to each other so as not to interfere with each other. Furthermore, it is preferable to apply a positive voltage to the area of the support table 4 facing the second FPG 3b for the second step S2, rather than to the entire surface of the support table 4 (i.e., it is desirable to form the aforementioned second conductive area (not shown) in an area substantially equal to the area facing the second FPG 3b). This configuration prevents changes in the process environment due to discharge from the support table 4 in the area not facing the second FPG 3b. When the second FPG 3b is swung depending on the position of the substrate main body 22, the position of the corresponding holder 4 changes, so it is desirable to change the range to which the voltage is applied to the holder 4 (the second conductive range (not shown) described above) depending on the irradiation position of the second FPG 3b. Similarly, when the first FPG 3a is swung, it is desirable to change the range to which the voltage is applied to the holder 4 (the first conductive range (not shown) described above) depending on the irradiation position of the first FPG 3a.

[Third step, fourth step]
After the second step S2, the gate valve 26 is opened, and the substrate body 22 is accommodated in the second processing chamber 104 where the third step is performed. After the substrate body 22 is accommodated in the second processing chamber 104, the holding side switch 11 is connected to the non-conductive side conductor 19, and the holding side circuit 13 is turned OFF.

In the second processing chamber 104, the substrate body 22 is subjected to processing in the third step (step S3, hereinafter referred to as "third step S3").

In the third step S3, a metal film 23 is deposited on the surface of the substrate body 22 that has been subjected to the first step S1 and the second step S2. The deposition of the metal film 23 is performed by, for example, a CVD (chemical vapor deposition) method or a PVD (sputtering) method. Examples of the metal film 23 include a copper film, a silver film, and a gold film. FIG. 1 shows a state in which a heater 29 for the CVD method is provided in the second processing chamber 104.
After the third step S3 is completed, the gate valve 27 is opened, the movable part 31 is moved into the vacuum reserve chamber 102, and the gate valve 27 is closed. After the pressure inside the vacuum reserve chamber 102 is returned to atmospheric pressure, the gate valve 38 is opened and the completed substrate 21 is removed.

In the fourth step (step S4, hereinafter referred to as "fourth step S4"), the substrate is removed from the substrate manufacturing system 100, and the surface of the substrate body 22 is subjected to metal plating and thermocompression bonding offline. The metal used for plating and thermocompression bonding in fourth step S4 is the same as the metal used in third step S3, such as copper, silver, or gold.

Furthermore, the fourth step S4 may be performed independently without performing the third step S3, but is preferably performed after the metal film 23 is formed on the surface of the substrate main body 22 in the third step S3. If a metal film is vapor-deposited in the third step S3, in the fourth step S4, the same metal is further plated or bonded by thermocompression bonding to form a metal layer such as the metal film 23 on the surface of the substrate main body 22.

In the second processing chamber 104, after the third step S3, the fourth step S4 may be performed in a vacuum without removing the substrate from the substrate manufacturing system 100. In this case, a metal foil is formed on the metal film 23 formed on the substrate body 22 in the third step S3. Because the entire process is performed in a vacuum, the Cu film can adhere to the metal foil without being affected by oxidation due to the atmosphere. This allows for a high degree of adhesion to be achieved.

[Modification of the substrate body and hydroxyl groups]
In this embodiment, the resin constituting the substrate body 22 may be polytetrafluoroethylene, and the atoms substituted with hydroxyl groups in the second step S2 may be fluorine. Alternatively, the resin constituting the substrate body 22 may be a liquid crystal polymer containing a wholly aromatic polyester.

[Action and effect]
As described above, in this embodiment, the time during which the holding-side circuit 13, which applies a holding-side voltage as a DC voltage to the substrate body 22, which is the resin to be irradiated with plasma, applies the holding-side voltage to the resin while the substrate is held on the holding table 4, and the time during which the plasma-side circuit 14, which is configured to apply a plasma-side voltage as a DC voltage to the FPG 3, which plasma-enhances the gas introduced by the gas inlet 15, applies the plasma-side voltage to the FPG 3, are set to be separate. This makes it possible to freely adjust the timing at which the FPG 3 generates ions and radicals to irradiate the resin held on the holding table 4 with the ions and radicals, and the state of the potential around the holding table 4 and the substrate body 22 held by the holding table 4, and to freely adjust the timing and state at which the ions and radicals act on the substrate body 22 while the substrate body 22 is accommodated in the vacuum chamber 2. This makes it possible to impart radicals in a suitable state to the surface of the substrate body 22, thereby providing high adhesion between the substrate body 22 and a metal layer, such as the metal film 23, on the surface of the substrate body 22 and firmly bonding them together.

In this embodiment, in the process of imparting hydroxyl groups to the substrate body 22, which has been irradiated with plasma by the plasma side circuit 14, resulting in at least some of the atoms constituting the substrate body 22 being released, the timing and state in which ions and radicals act on the substrate body 22 can be freely adjusted. This allows radicals to be imparted to the surface of the substrate body 22 in an optimal state, providing high adhesion between the resin substrate body 22 and a metal layer such as the metal film 23 on the surface of the substrate body 22, thereby firmly bonding them together.

In this embodiment, the ON/OFF control of the plasma-side switch 12, which serves as the application time adjustment unit for the plasma-side circuit 14, sets the time during which the plasma-side circuit 14 applies the plasma-side voltage to the holding table 4 to be shorter than the time during which the holding-side circuit 13 applies the holding-side voltage to the holding table 4. This generates a potential difference between the periphery of the substrate body 22 held on the holding table 4 and the area inside the vacuum chamber 2 other than the periphery of the substrate body 22, even before and after the plasma irradiation process using the FPG 3, making it possible to easily control the distribution of ions and radicals inside the vacuum chamber 2 over a long period of time. This allows various types of radicals to be applied to the surface of the substrate body 22 in an optimal state, providing high adhesion between the substrate body 22 and a metal layer, such as the metal film 23, on the surface of the substrate body 22, thereby firmly bonding them together.

In this embodiment, the plasma-side switch 12, which controls the application of the plasma-side voltage on and off, allows the voltage application time and application timing to be appropriately adjusted, making it possible to appropriately process the surface of the substrate body 22 with simple operations.

In this embodiment, the holding voltage is applied during the process of introducing gas into the vacuum chamber 2, converting the gas into plasma, and irradiating the surface of the substrate body 22. When the FPG 3 irradiates the surface of the substrate body 22 with plasma, the holding voltage adjusts the potential state of the substrate body 22, controlling the approach and separation of ions and radicals to and from the surface of the substrate body 22, thereby enabling appropriate control of the action of ions and radicals on the surface of the substrate body 22 for each process.

In this embodiment, a positive voltage is applied to the FPG3 as a plasma-side voltage, generating plasma that irradiates the surface of the resin with positive ions, causing the surface of the resin to be detached by ion collisions. Furthermore, by applying a positive voltage to the resin as a retention-side voltage, the potential difference between the FPG3 and the resin is reduced and the potential difference between the FPG3 and portions other than the substrate body 22 is relatively increased, attracting positive ions to portions other than the substrate body 22 and preventing continued ion collisions with the surface of the substrate body 22. This makes it possible to appropriately control the processing and surface modification of the surface of the substrate body 22 using plasma.

In this embodiment, by applying a holding-side voltage to at least a portion of the holding table 4 that depends on the position where the substrate body 22 is located, the potential difference between the FPG 3 and the substrate body 22 at the position where the substrate body 22 is located is reduced, making it possible to impart radicals to the surface of the substrate body 22 in more optimal conditions.

It goes without saying that the above-described embodiment is merely an example of the present invention, and does not mean that the present invention is limited to the above-described embodiment alone. In other words, various modifications and applications of the present embodiment are possible as long as they are suitable for solving the problems of the present invention.

The plasma processing apparatus and plasma processing method of this embodiment are used, for example, in the manufacture of circuit boards used in mobile phones that communicate large volumes of information at high speed. Fluororesin has the second lowest dielectric constant after air, making fluororesin substrates particularly suitable as a material for high-frequency substrates. Compared to circuit boards made from other common materials, circuit boards made from fluororesin have a lower dielectric constant and dielectric loss tangent, and exhibit smaller dielectric loss, even when high-frequency current is passed through them.

When the plasma processing apparatus and plasma processing method of this embodiment are applied to the manufacture of fluororesin substrates, the hydrophilicity of the manufactured substrate is improved, improving adhesion to copper wiring and providing a circuit board that can withstand use in high frequency bands. This technology that can be applied to use in high frequency bands is not limited to mobile phone bodies, but can also be applied to substrates used in mobile phone base stations, substrates for communication in homes, factories, or for regional use, and substrates for millimeter-wave radar used in autonomous driving of automobiles or drones. The plasma processing apparatus and plasma processing method of this embodiment can also be used to manufacture substrates in a variety of fields other than those mentioned above.

1: Plasma processing apparatus 2: Vacuum chamber (chamber)
3...FPG (plasma irradiation device)
3a...First FPG (plasma irradiation device)
3b: Second FPG (plasma irradiation device)
4... Holding stand (holding part)
13: Holding side circuit 14: Plasma side circuit 15: Gas inlet 22: Substrate body (resin)

Claims (5)

A plasma processing apparatus that irradiates a surface of a resin present in a chamber with plasma to improve the wettability of the surface of the resin,
a holding circuit having a holding portion that holds the resin to be irradiated with the plasma, and applying a holding voltage to the held resin;
a gas inlet for introducing a gas into the chamber;
a plasma irradiation device for converting the gas into plasma, and a plasma-side circuit configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device;
the plasma treatment device is configured to perform a first step of irradiating the resin with plasma from a plasma side circuit to remove at least a portion of atoms constituting the resin, and a second step of imparting hydroxyl groups to the resin from which at least a portion of the atoms have been removed in the first step;
a time during which the holding-side circuit applies the holding-side voltage to the resin and a time during which the plasma-side circuit applies the plasma-side voltage to the plasma irradiation device are set to be separate from each other;
The plasma side circuit is characterized in that it has an application time adjustment unit for setting the time for which the plasma side circuit applies the plasma side voltage to be shorter than the time for which the holding side voltage is applied to the holding side circuit, during the period from when the resin in the first step has been subjected to at least some of the atoms constituting the resin being released to when hydroxyl groups are added in the second step. A plasma processing apparatus that irradiates a surface of a resin present in a chamber with plasma to improve the wettability of the surface of the resin,
a holding circuit having a holding portion that holds the resin to be irradiated with the plasma, and applying a holding voltage to the held resin;
a gas inlet for introducing a gas into the chamber;
a plasma irradiation device for converting the gas into plasma, and a plasma-side circuit configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device;
the plasma treatment device is configured to at least perform a first step of irradiating the resin with plasma from a plasma side circuit to remove at least a portion of atoms constituting the resin, and a second step of imparting hydroxyl groups to the resin from which at least a portion of the atoms have been removed in the first step;
The plasma side circuit and the holding side circuit are
In the first step, a first voltage application unit turns on the plasma-side circuit to apply the plasma-side voltage to the plasma irradiation device and turns off the holding-side circuit;
a second voltage application unit that turns off the plasma-side circuit and turns on the holding-side circuit to apply the holding-side voltage to the holding unit during the period from the end of the first step to the start of the second step;
a third voltage application unit that turns on the plasma-side circuit to apply the plasma-side voltage to the plasma irradiation device and turns on the holding-side circuit to apply the holding-side voltage to the holding unit in the second step;
A plasma processing apparatus comprising: 3. The plasma processing apparatus according to claim 1 , wherein the plasma side circuit and the holding side circuit are configured so that the time for applying the holding side voltage and the time for applying the plasma side voltage are separate in order to perform the second process of adding hydroxyl groups to the resin that has undergone the first process. a chamber containing a resin to be irradiated with plasma;
a holding circuit having a holding portion that holds the resin to be irradiated with the plasma, and applying a holding voltage to the held resin;
a gas inlet for introducing a gas into the chamber;
a plasma irradiation device for converting the gas into plasma, and a plasma-side circuit configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device;
A plasma processing method for improving wettability of a surface of a resin present in the chamber by irradiating the surface of the resin with plasma, the method comprising:
The plasma treatment method is configured to carry out a first step of irradiating the resin with plasma from a plasma side circuit to remove at least a portion of atoms constituting the resin, and a second step of imparting hydroxyl groups to the resin from which at least a portion of the atoms have been removed in the first step,
a time during which the holding-side circuit applies the holding-side voltage to the resin and a time during which the plasma-side circuit applies the plasma-side voltage to the plasma irradiation device are set to be separate from each other;
A plasma processing method characterized in that an application time adjustment unit provided in the plasma side circuit for adjusting the time for which the plasma side circuit applies the plasma side voltage is set so that the time for which the plasma side circuit applies the plasma side voltage is shorter than the time for which the holding side voltage is applied to the holding side circuit, during the period from when the resin in the first step has been subjected to the removal of at least a portion of the atoms constituting the resin to when hydroxyl groups are added in the second step. 1. A plasma processing method for improving the wettability of a surface of a resin present in a chamber by irradiating the surface of the resin with plasma, comprising:
The plasma processing apparatus for performing the plasma processing method includes:
a holding circuit having a holding portion that holds the resin to be irradiated with the plasma, and applying a holding voltage to the held resin;
a gas inlet for introducing a gas into the chamber;
a plasma irradiation device for converting the gas into plasma, and a plasma-side circuit configured to apply a plasma-side voltage as a DC voltage to the plasma irradiation device;
the plasma treatment device is configured to at least perform a first step of irradiating the resin with plasma from a plasma side circuit to remove at least a portion of atoms constituting the resin, and a second step of imparting hydroxyl groups to the resin from which at least a portion of the atoms have been removed in the first step;
The plasma side circuit and the holding side circuit are
a first voltage application step in which the plasma-side circuit is turned on to apply the plasma-side voltage to the plasma irradiation device and the holding-side circuit is turned off in the first step;
a second voltage application step in which, during the period from the end of the first step to the start of the second step, the plasma-side circuit is turned off and the holding-side circuit is turned on to apply the holding-side voltage to the holding unit;
a third voltage application step in which, in the second step, the plasma-side circuit is turned on to apply the plasma-side voltage to the plasma irradiation device and the holding-side circuit is turned on to apply the holding-side voltage to the holding unit;
A plasma processing method comprising: