Disclosure of Invention
The present invention has been made to solve the above-described problems, and its main object is to achieve continuous plasma treatment even on a substrate which is difficult to wind up on a roll.
That is, the present invention provides a plasma processing apparatus including a plurality of plasma processing chambers for performing plasma processing on a substrate, a tray for holding the substrate in an upright state, and a lifting mechanism for continuously conveying the tray to the plurality of plasma processing chambers.
According to the plasma processing apparatus having such a configuration, since the tray holding the substrate is continuously transported to the plurality of plasma processing chambers by the elevating mechanism, even if the substrate is difficult to wind around the rollers, continuous film formation processing can be performed.
Preferably, the plurality of plasma processing chambers are communicated with each other, and a differential exhaust chamber is provided between the plasma processing chambers.
According to this configuration, by communicating the plurality of plasma processing chambers, continuous conveyance of the tray can be achieved while each plasma processing chamber can be maintained at a desired vacuum degree.
In order to simplify the lift mechanism, it is preferable that the lift mechanism has a rope that is bridged across the plurality of plasma processing chambers, on which the tray is hung, and a drive source that moves the rope between the plurality of plasma processing chambers.
Preferably, the plasma processing apparatus further includes a conveying mechanism, and a plurality of trays are provided on the conveying mechanism, and the plurality of trays are sequentially conveyed to the rope.
According to this configuration, a plurality of trays can be automatically sequentially fed out, and a plurality of substrates held in the plurality of trays can be continuously formed at one time, thereby further improving the efficiency.
As a means for automatically feeding out the tray, there is a means in which the conveying mechanism has an endless belt for conveying the tray to the rope, the tray falls from an edge portion of the endless belt, a hook portion provided on the tray is hung on the rope, and the tray is hung on the rope.
Preferably, the plasma processing chamber includes a plasma cleaning chamber for cleaning the substrate, an ion implantation chamber for implanting carbon ions into the substrate, a first film forming chamber for forming a DLC film on one surface of the substrate, a second film forming chamber for forming a DLC film on the other surface of the substrate, and a hydrophilic processing chamber for performing hydrophilic processing on the substrate by oxygen plasma, wherein the tray is sequentially transferred to the plasma cleaning chamber, the ion implantation chamber, the first film forming chamber, the second film forming chamber, and the hydrophilic processing chamber by the elevating mechanism.
According to this configuration, since the tray holding the substrate in the standing state is transferred to the plasma cleaning chamber, the ion implantation chamber, the first film formation chamber, the second film formation chamber, and the hydrophilic treatment chamber, plasma treatment can be performed on both surfaces of the substrate in each chamber, and therefore, a DLC film can be efficiently formed on the substrate.
As a more specific embodiment for performing plasma treatment on both sides of a substrate, there may be mentioned a plasma cleaning chamber, an ion implantation chamber, and a hydrophilic treatment chamber each provided with at least one pair of antennas for generating plasma in the chamber at positions sandwiching the substrate.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention thus constituted, even a substrate which is difficult to wind around a roll can be continuously subjected to plasma treatment.
Detailed Description
An embodiment of a plasma processing apparatus according to the present invention will be described below with reference to the accompanying drawings.
The plasma processing apparatus according to the present embodiment is a continuous film forming apparatus capable of continuously forming a film on a plurality of substrates, and will be described below by taking as an example a gas barrier film having acid and alkali corrosion resistance, which is used for manufacturing a separator for a fuel cell or the like, on a substrate. The base material is, for example, an aluminum substrate, and the gas barrier film is, for example, a DLC film that has conductivity and suppresses penetration of sulfuric acid water that causes corrosion. However, the substrate and the film to be formed on the substrate are not limited to the following embodiments, and may be changed according to circumstances.
As shown in fig. 1 and 2, the plasma processing apparatus 100 holds a substrate on a tray Y in a standing state while conveying the substrate X together with the tray Y to a plurality of plasma processing chambers S2 to S6. The standing state is preferably a state along the vertical direction, but is not necessarily limited to this state, and may be a state inclined from the vertical direction. As shown in fig. 3, the tray Y has a frame shape, and a plurality of substrates X are vertically and horizontally suspended and held in the frame.
Specifically, as shown in fig. 1 and 2, the plasma processing apparatus 100 includes a tray delivery chamber S1, a plasma cleaning chamber S2, an ion implantation chamber S3, a first film formation chamber S4, a second film formation chamber S5, a hydrophilic processing chamber S6, a tray storage chamber S7, and a lift mechanism 10 for conveying the substrate X to each chamber together with the tray Y.
The tray delivery chamber S1 accommodates a plurality of trays Y, and delivers the trays Y to each processing chamber described later in sequence. The tray delivery chamber S1 is evacuated by a suction mechanism P such as a vacuum pump, and maintained at a predetermined vacuum level.
The substrate X held on the tray Y is fed into the plasma cleaning chamber S2 together with the tray Y fed from the tray feeding chamber S1, and the plasma cleaning chamber S2 is a processing chamber for performing plasma cleaning on the substrate X. Specifically, at least one pair of antennas 2 is provided in the plasma cleaning chamber S2 at a position sandwiching the substrate X, and in this embodiment, the pair of inductively coupled antennas 2 are provided in two groups, and are arranged side by side in the conveying direction. Then, high-frequency power from a high-frequency power source (not shown) is applied to these antennas 2 by an integrator (not shown), and argon gas is supplied as a cleaning gas into the chamber, whereby inductively coupled discharge plasma including argon ions is generated near the front and back surfaces of the substrate X. One surface (hereinafter referred to as a front surface) and the other surface (hereinafter referred to as a back surface) of the substrate X are cleaned by the argon plasma.
Along with the tray Y sent out from the plasma cleaning chamber S2, the substrate X held on the tray Y is sent into the ion implantation chamber S3, and the ion implantation chamber S3 is a processing chamber for implanting carbon ions into the substrate X. Such ion implantation is to form a core (so to speak, like the root of hair) on the substrate X to improve adhesion of a DLC coating described later. Specifically, at least one pair of antennas 2 is provided in the ion implantation chamber S3 at a position sandwiching the substrate X, and in this embodiment, the pair of inductive coupling antennas 2 are provided in two groups, and are arranged side by side in the conveyance direction. High-frequency power from a high-frequency power source (not shown) is applied to these antennas 2 through an integrator (not shown), and a carbon compound gas such as methane, which is a raw material gas, is supplied into the chamber, whereby inductively coupled discharge plasma containing carbon ions is generated near the front and rear surfaces of the substrate X. Then, a negative dc voltage or a negative pulse voltage from a bias power supply (not shown) is applied to the substrate X, and carbon ions are implanted into the front and back surfaces of the substrate X to form nuclei contributing to improvement of adhesion of the DLC coating.
The substrate X held on the tray Y is fed into the first film forming chamber S4 together with the tray Y fed from the ion implantation chamber S3, and the first film forming chamber S4 is a processing chamber for forming a DLC film on one surface (surface) of the substrate X. Specifically, in the first film forming chamber S4, one or more antennas 2 are provided on the surface side of the substrate X, and in this embodiment, five inductively coupled antennas 2 are provided side by side in the conveying direction. On the other hand, a heater 3 is provided on the back surface of the substrate X.
Then, a high-frequency power from a high-frequency power source (not shown) is applied to the antenna 2 via an integrator (not shown), and a mixed gas of nitrogen, methane, and acetylene is supplied into the chamber as a raw material gas, whereby an inductively coupled discharge plasma including carbon ions is generated in the vicinity of the surface of the substrate X. At this time, in order to make the DLC coating conductive, the substrate X base surface is heated to, for example, 150 to 400 ℃ by the heater 3 described above. Then, a negative dc voltage or a negative pulse voltage from a bias power supply (not shown) is applied to the substrate X, and the substrate X is further heated by the heater 3 or ions in the plasma, whereby a conductive DLC film is formed on the surface of the substrate X.
The substrate X held by the tray Y is fed into the second film forming chamber S5 together with the tray Y fed from the first film forming chamber S4, and the second film forming chamber S5 is a processing chamber for forming a DLC film on the other surface (back surface) of the substrate X. Specifically, in the second film forming chamber S5, one or more antennas 2 are provided on the back surface of the substrate X, and in this embodiment, five inductively coupled antennas 2 are provided side by side in the conveying direction. On the other hand, a heater 3 is provided on the front surface side of the substrate X.
Then, high-frequency power from a high-frequency power source (not shown) is applied to the antenna 2 via an integrator (not shown), and a mixed gas of, for example, nitrogen, methane, and acetylene is supplied as a raw material gas into the chamber, whereby an inductively coupled discharge plasma including carbon ions is generated near the back surface of the substrate X. At this time, in order to make the DLC coating conductive, the substrate X base surface is heated to, for example, 150 to 400 ℃ by the heater 3 described above. Then, a negative dc voltage or a negative pulse voltage from a bias power supply (not shown) is applied to the substrate X, and the substrate X is further heated by the heater 3 or ions in the plasma, so that a conductive DLC film is formed on the back surface of the substrate X.
The substrate X held on the tray Y is fed into the hydrophilic treatment chamber S6 together with the tray Y fed from the second film forming chamber S5, and the hydrophilic treatment chamber S6 is a treatment chamber for subjecting the substrate X to hydrophilic treatment to impart hydrophilicity to the substrate X. Specifically, at least one pair of antennas 2 is provided in the hydrophilic treatment chamber S6 at a position sandwiching the substrate X, and in this embodiment, one set of these pairs of inductively coupled antennas 2 is provided. Then, high-frequency power from a high-frequency power source (not shown) is applied to these antennas 2 via an integrator (not shown), and oxygen gas is supplied into the chamber, whereby inductively coupled discharge plasma containing oxygen ions is generated near the front and back surfaces of the substrate X. By such oxygen plasma, hydrophilic treatment is performed on one surface and the back surface of the substrate X.
The substrates X held on the tray Y are sent to the tray housing chamber S7 together with the tray Y sent from the hydrophilic processing chamber S6, and the tray housing chamber S7 houses and stores the substrates X. The tray storage chamber S7 is evacuated by a suction mechanism P such as a pump, for example, and maintains a predetermined vacuum degree.
The tray delivery chamber S1, the plasma cleaning chamber S2, the ion implantation chamber S3, the first film formation chamber S4, the second film formation chamber S5, the hydrophilic treatment chamber S6, and the tray storage chamber S7 are in communication with each other, and a differential exhaust chamber S8 is provided between the plasma cleaning chamber S2 and the ion implantation chamber S3, between the ion implantation chamber S3 and the first film formation chamber S4, and between the second film formation chamber S5 and the hydrophilic treatment chamber S6, and the differential exhaust chamber S8 is exhausted by a suction mechanism P1 such as a common pump. And, all of these chambers are communicated through a slit (not shown) through which the tray Y can pass, whereby the plasma cleaning chamber S2, the ion implantation chamber S3, the first film formation chamber S4, the second film formation chamber S5, and the hydrophilic treatment chamber S6 are differentially exhausted. Therefore, the plasma processing chambers S2 to S6 can be maintained at a predetermined vacuum degree without providing a gate valve or the like between the chambers.
The elevating mechanism 10 continuously conveys the tray Y into the plurality of plasma processing chambers S2 to S6. The elevating mechanism 10 sequentially conveys the tray Y to the plasma cleaning chamber S2, the ion implantation chamber S3, the first film formation chamber S4, the second film formation chamber S5, and the hydrophilic treatment chamber S6, and more specifically, from the tray discharge chamber S1 to the tray storage chamber S7.
Specifically, as shown in fig. 4, the lift mechanism 10 includes a rope 11 that spans across the plurality of plasma processing chambers S1 to S6, and a driving source such as a motor (not shown) that moves the rope 11 between the plurality of plasma processing chambers S2 to S6.
As shown in fig. 2 and 4, a hook portion Ya of the tray Y according to the present embodiment for hooking the rope 11 is provided at an upper end portion, for example, and can be hung on the rope 11.
The rope 11 is a rope hooked by the hook portion Ya of the tray Y, and is made of, for example, metal, glass fiber, carbon fiber, or the like, and is a stainless steel rope.
In the present embodiment, the rope 11 spans across each of the tray sending-out chamber S1 to the tray receiving chamber S7, and after moving from the tray sending-out chamber S1 to the tray receiving chamber S7 above each of the chambers, moves from the tray receiving chamber S7 to the tray sending-out chamber S1 below each of the chambers, and rotates around these chambers.
Further, as shown in fig. 4, the plasma processing apparatus 100 of the present embodiment includes a conveying mechanism 12, and a plurality of trays Y are arranged side by side on the conveying mechanism 12 and are sequentially conveyed to the ropes 11.
The conveyor 12 has a plurality of trays Y placed thereon, and sequentially conveys the trays Y to the rope 11, specifically, for example, a pair of rollers 13 and an endless belt 121 wound around the rollers 13.
The relative positional relationship between the conveyor 12 and the rope 11 is set such that the tray Y is suspended from the rope 11 by the hook portion Ya of the tray Y falling from the edge of the endless belt 121 and being suspended from the rope 11.
More specifically, when the tray Y placed on the endless belt 121 and facing the rope 11 passes the apex of the roller 13 in front of the winding of the endless belt 121, it starts to gradually descend along the surface of the roller 13, and becomes an inclined state of being inclined forward. The rope 11 and the endless belt 121 are arranged such that the hook portion Ya of the tray Y is hung on the rope 11 before the tray Y falls down.
The plasma processing apparatus 100 according to the present embodiment is further provided with a carry-out mechanism (not shown) for sequentially receiving the trays Y from the rope after the film formation process.
The carry-out mechanism has the same configuration as the conveying mechanism 12 shown in fig. 4, and receives the tray Y by the reverse operation of the conveying mechanism 12 described above.
That is, such a carry-out mechanism has, for example, a pair of rollers and an endless belt wound around the rollers. Then, the tray Y fed by the rope 11 is lifted up by being placed on the endless belt, and the hook portion Ya of the tray Y is separated from the rope 11, whereby the tray Y is recovered.
With this configuration, the plurality of trays Y placed on the conveyor 12 are fed out to the rope 11, automatically and sequentially moved onto the rope 11, and thereafter, the rope 11 is moved by a driving source such as a motor (not shown) and sequentially and automatically conveyed to the plasma processing chambers S2 to S6.
A negative dc voltage or a negative pulse voltage (bias voltage) from the bias power supply (not shown) is applied to the cord 11, and the bias voltage is applied to the base material X through the cord 11 and the tray Y suspended from the cord 11.
According to the plasma processing apparatus 100 of the present embodiment configured as described above, the tray Y holding the substrate X can be continuously transported to the plurality of plasma processing chambers S2 to S6 by the elevating mechanism 10, so that even if the substrate X is difficult to roll up, continuous film formation processing can be performed. Of course, it is needless to say that the plasma processing apparatus 100 can be applied to the substrate X which is not difficult to roll up.
Further, since the plurality of plasma processing chambers S2 to S6 are communicated with each other and the respective processing chambers are differentially exhausted, the plurality of plasma processing chambers S2 to S6 are communicated with each other, so that the tray Y can be continuously conveyed and the respective plasma processing chambers S2 to S6 can be maintained at a desired vacuum degree.
In addition, since the elevating mechanism 10 is constituted by the rope 11 stretched across the plurality of plasma processing chambers S2 to S6, and the tray Y can be hung on the rope 11, the elevating mechanism 10 can be constituted simply.
Further, since the conveyor 12 sequentially feeds out the plurality of trays Y to the rope 11, the feeding out of the plurality of trays Y can be automated, and the plurality of substrates X held in the plurality of trays Y can be continuously formed at one time, thereby further improving the efficiency.
Further, since the conveyor 12 has the endless belt 121 for feeding the tray Y to the rope 11, the tray Y is dropped from the edge of the endless belt 121, and the hook portion Ya provided on the tray Y is hung on the rope 11, so that the tray Y is hung on the rope 11, the tray Y can be automatically fed out with a simple configuration.
Further, since the tray Y holding the substrate X in the standing state is transferred to the plasma cleaning chamber S2, the ion implantation chamber S3, the first film formation chamber S4, the second film formation chamber S5, and the hydrophilic treatment chamber S6, and the pair of antennas 2 are provided in the plasma cleaning chamber S2, the ion implantation chamber S3, and the hydrophilic treatment chamber S6 so as to sandwich the substrate X, plasma treatment can be performed on both surfaces of the substrate X in each chamber, and DLC coating can be generated more effectively than before.
The present invention is not limited to the above embodiments.
For example, in the above embodiment, the rope 11 is described as a stainless steel rope, but when the rope 11 is made of a conductive material such as metal or carbon fiber, the bias voltage is applied to the base material X by the rope 11, so that the bias voltage of the same magnitude can be simultaneously applied to the plurality of base materials X held in the respective trays Y.
Instead, the cord 11 may also be made of a non-conductive material such as glass cord or the like. In this case, as shown in fig. 5, for example, a conductive member D such as a pantograph may be provided in each of the plasma processing chambers S2 to S6 in advance, and a bias voltage may be applied to the substrate X through the conductive member D. In addition, in order to enable the bias voltage to be applied to the substrate X at an appropriate timing, the hook portion Ya may be elongated in the conveying direction as shown in fig. 5.
With this configuration, bias voltages of different magnitudes can be applied to the substrate X in the respective plasma processing chambers S2 to S6. Since a bias voltage of a suitable magnitude for the process in each of the plasma process chambers S2 to S6 can be applied to the substrate X, the degree of freedom in the film formation process can be improved, and a film of higher quality can be formed.
Further, in the above-described embodiment, the ropes 11 are provided so as to pass above and below the plasma processing chambers S2 to S6, but the arrangement of the ropes 11 is not limited thereto, and for example, as shown in fig. 6, the ropes 11 may be arranged to move back and forth between the respective plasma processing chambers S2 to S6 above the plasma processing chambers S2 to S6.
The substrate X is not limited to aluminum, and may have at least one metal among alloys such as nickel (Ni), iron (Fe), magnesium (Mg), titanium (Ti), and stainless steel containing these metals.
Further, not only those methods described in the above embodiments may be used to form the gas barrier film, but also, for example, a plasma CVD method, a vacuum evaporation method, a sputtering method, an ion plating method, or the like may be used.
It goes without saying that the present invention is not limited to the above-described embodiment, and other various modifications are possible within a range not deviating from the object of the present invention.