Plasma processing apparatus

Abstract

To provide a plasma processing apparatus capable of suppressing discharge between a base material and an electrode caused by contact or approach of the base material with / to the plasma processing apparatus.SOLUTION: A plasma processing apparatus that blows a plasma-containing gas generated by applying a voltage to a material gas flowing in a gas passage onto a base material being processed, comprises: a pair of electrodes that are opposite each other in a first direction; a power supply unit that applies a voltage to the pair of electrodes; a gas blowout part that blows the plasma-containing gas toward the outside; a measurement unit that measures at least one of a temperature near the gas blowout part and a pressure in he gas passage; and a control unit that changes an operation of the power supply unit when a temporal change based on the measurement value measured by the measurement unit indicates a change to an extent exceeding a predetermined reference behavior.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus.

Background Art

[0002] Plasma processing apparatuses are used in manufacturing processes for plastics, paper, fibers, semiconductors, liquid crystals, films, etc. In a plasma processing apparatus, a discharge space is formed inside, and when a source gas is passed through the discharge space, a part of the source gas is turned into plasma. More specifically, due to this plasma conversion, the source gas is in a state containing active species such as radicals. Hereinafter, the gas in a state where a part is turned into plasma is referred to as a "plasma-containing gas". A plasma processing apparatus is a device that generates a plasma-containing gas and blows it out to the outside.

[0003] In recent years, a plasma-containing gas has been blown onto a base material such as paper or film to perform plasma processing on the surface of the base material. According to plasma processing, for example, it is possible to improve the hydrophilicity of the surface of the base material or remove organic substances present on the surface of the base material. The present applicant has disclosed a plasma processing apparatus capable of generating a plasma-containing gas and blowing the plasma-containing gas onto a base material (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the inventor studied the plasma treatment of the substrate, it was found that the substrate may be deformed in a wavy manner due to the pressure difference caused by the spraying of the plasma-containing gas and the thermal stress generated by the temperature distribution in the main surface of the substrate. When the substrate is deformed in a wavy manner, the substrate and the plasma treatment apparatus approach locally. For example, when the substrate is in the transport state, the substrate may come into contact with the plasma treatment apparatus due to deformation, and the transport of the substrate may be stagnated.

[0006] FIG. 13A is a perspective view schematically showing a state in which a substrate M1 in a transport state is deformed and contacts a plasma treatment apparatus 100, and the transport of the substrate M1 is stagnated, as an example. FIG. 13B is a cross-sectional view taken along line B-B of FIG. 13A, and is a drawing showing some components in a block diagram.

[0007] As shown in FIG. 13A, the plasma treatment apparatus 100 includes a plasma generation unit 101 and a transport unit 102. In FIGS. 13A and 13B, the direction in which the substrate M1 and the plasma generation unit 101 face each other is defined as the Z direction, and an X - Y - Z coordinate system in which a plane orthogonal to the Z direction is the XY plane is shown.

[0008] As shown in FIG. 13B, the plasma generation unit 101 includes a pair of electrodes (103, 104) facing each other in the X direction, a power supply unit 110 that applies a voltage to the pair of electrodes (103, 104), a gas flow path 107 through which a raw material gas G1 flows, and a gas blowing unit 109 that blows out the generated plasma-containing gas G2. In FIG. 13B, an example in which a dielectric 105 is disposed between the pair of electrodes (103, 104) is shown.

[0009] The transport unit 102 transports the substrate M1 in the X direction by a plurality of rollers 102a. The plasma generation unit 101 generates a plasma-containing gas G2 inside and blows the plasma-containing gas toward the substrate M1 in the transport state.

[0010] The base material M1 may be deformed in a wavy manner due to a difference in air pressure or the like generated by spraying the plasma-containing gas G2. As a result, as shown in FIGS. 13A and 13B, the base material M1 may come into contact with the plasma processing apparatus 100, and the conveyance of the base material M1 may be stalled.

[0011] When the base material M1 comes into contact with the plasma processing apparatus and the conveyed base material M1 stalls, the plasma-containing gas G2 is locally sprayed, and the temperature of the base material M1 rises, so that the base material M1 is locally softened. Further, the conductivity of the base material M1 increases (also referred to as "carbonization"), and a discharge S10 is likely to occur between the base material M1 and the electrode 103. Although not shown, the discharge S10 can also occur when the base material M1 approaches the gas blowing portion 109 due to the deformation of the base material M1 when the stationary base material M1 is plasma-processed.

[0012] When a discharge S10 occurs between the base material M1 and the electrode 103, the base material M1 may deteriorate or smoke, and it is preferable to suppress the occurrence of the discharge S10. That is, there is room for improvement in terms of suppressing the discharge S10 when the base material M1 comes into contact with or approaches the plasma processing apparatus 1.

[0013] In view of the above, an object of the present invention is to provide a plasma processing apparatus capable of suppressing a discharge between a base material and an electrode caused by contact or proximity of the base material to the plasma processing apparatus.

Means for Solving the Problems

[0014] The plasma processing apparatus according to the present invention is a plasma processing apparatus that sprays a plasma-containing gas generated by applying a voltage to a raw material gas flowing through a gas flow path onto a base material to be processed, a pair of electrodes facing each other in a first direction, a power supply unit that applies a voltage between the pair of electrodes, a gas blowing portion that blows the plasma-containing gas outward, A measuring unit that measures at least one of the temperature near the gas blowing unit and the pressure in the gas flow path; A control unit that changes the operation of the power supply unit when a change over time based on the measurement value measured by the measuring unit indicates a change exceeding a predetermined reference mode.

[0015] As described with reference to FIGS. 13A and 13B, when the substrate stagnates in contact with the plasma processing apparatus, a large amount of plasma-containing gas is locally sprayed onto the substrate. As a result, the conductivity increases as the substrate becomes hot, and discharge is likely to occur between the substrate and the electrode provided in the plasma processing apparatus. For this reason, when the conveyance of the substrate stagnates, it is preferable to change the operation of the power supply unit for generating the plasma-containing gas.

[0016] When the substrate becomes hot, the temperature near the gas blowing unit that blows out the plasma-containing gas rises. In other words, when the temperature near the gas blowing unit rises, there is a high possibility that the substrate is in contact with the plasma processing apparatus. Therefore, the temperature near the gas blowing unit is suitable as an indicator that the substrate is in contact with the plasma processing apparatus.

[0017] Here, the “vicinity of the gas blowing unit” means that the distance from the gas blowing unit is 20 mm or less in the direction in which the substrate and the gas blowing unit face each other.

[0018] Further, when the substrate comes into contact with the plasma processing apparatus, a part of the gas blowing unit is blocked by the substrate. Along with this, the pressure in the gas flow path through which the source gas or the plasma-containing gas flows increases. In other words, when the pressure in the gas flow path increases, there is a high possibility that the substrate is in contact with the plasma processing apparatus. Therefore, similar to the above temperature, the pressure in the gas flow path is suitable as an indicator that the substrate is in contact with the plasma processing apparatus.

[0019] Therefore, when the change over time based on at least one of the temperature near the gas blowing portion or the pressure in the gas flow path shows a change exceeding a predetermined reference mode, the control unit can suppress the discharge between the base material and the electrode caused by the contact of the base material with the plasma processing apparatus by changing the operation of the power supply unit. As an example, the reference mode can be set based on the state where the base material and the plasma processing apparatus are not in contact.

[0020] In addition, a method of setting a threshold value in advance for the temperature near the gas blowing portion or the pressure in the gas flow path and determining that the base material has come into contact with the plasma processing apparatus when the temperature or the pressure exceeds the threshold value is also conceivable. However, both the temperature and the pressure vary depending on the spraying conditions of the plasma-containing gas on the base material.

[0021] For example, the temperature near the gas blowing portion depends on the input power for generating the plasma-containing gas. Therefore, even if a threshold value is set for the temperature near the gas blowing portion, a situation may occur where the temperature exceeds the threshold value but the base material is not in contact with the plasma processing apparatus. Further, the pressure in the gas flow path depends on the flow rates of the raw material gas and the plasma-containing gas. Therefore, even if a threshold value is set for the pressure in the gas flow path, it is considered that the proximity of the base material and the plasma processing apparatus cannot be accurately detected in the same way as the discussion of the temperature near the gas blowing portion.

[0022] Therefore, it is preferable that the control unit changes the operation of the power supply unit based on the change over time of the temperature or the pressure.

[0023] In the above description, the case where a substrate in a transport state comes into contact with the plasma processing apparatus has been described as an example. However, even when both the substrate and the plasma processing apparatus are in a stationary state and the substrate is plasma processed, the substrate may be deformed by the spraying of the plasma-containing gas and approach the plasma processing apparatus. Even in this case, the same discussion as above is possible regarding the point that the approach of the substrate to the plasma processing apparatus can be determined based on the temperature in the vicinity of the gas blowing portion or the pressure in the gas flow path. That is, the above configuration is not limited to the example of plasma processing a substrate in a transport state. Specific examples will be described later.

[0024] In the above plasma processing apparatus, When the increase value of at least one of the temperature in the vicinity of the gas blowing portion and the pressure in the gas flow path with respect to a predetermined elapsed time exceeds a predetermined value, the control unit may change the operation of the power supply unit.

[0025] As described above, it is difficult to determine the contact between the substrate and the plasma processing apparatus by setting a predetermined threshold value for the above temperature or pressure. On the other hand, in the above configuration, the control unit changes the operation of the power supply unit according to the increase value of the above temperature or pressure with respect to a predetermined elapsed time. Although details will be described later, when the substrate is not in contact with the plasma processing apparatus, the increase value of the above temperature or pressure with respect to a predetermined elapsed time is relatively small. Therefore, based on this increase value, it is possible to determine that the substrate has come into contact with the plasma processing apparatus.

[0026] Also, in the above plasma processing apparatus, The measurement unit is arranged in the vicinity of the gas blowing portion and has a plurality of temperature sensors arranged in a plane parallel to the main surface of the substrate and in a second direction orthogonal to the first direction. When the temperature difference between two measurement values extracted from the measurement values measured by the plurality of temperature sensors exceeds a predetermined value as time elapses, the control unit may change the operation of the power supply unit.

[0027] In the above plasma processing apparatus, The measurement unit may include a temperature sensor disposed near the gas blowing unit and a pressure sensor disposed in the gas flow path.

[0028] According to the above configuration, when either the temperature near the gas blowing unit or the pressure in the gas flow path shows a change exceeding a predetermined reference state, the operation of the power supply unit is changed. Therefore, it is possible to more accurately determine the contact or proximity of the base material to the gas blowing unit, and it is possible to more strongly suppress the occurrence of discharge between the base material and the electrode.

[0029] In the above plasma processing apparatus, the measurement unit includes a temperature sensor disposed near the gas blowing unit, the temperature sensor may be in contact with the electrode on the low potential side among the pair of electrodes.

[0030] According to the above configuration, the influence of the high-frequency voltage applied by the power supply unit to the pair of electrodes on the measurement accuracy of the temperature sensor is suppressed, which is preferable. Note that the "electrode on the low potential side" refers to the electrode on the side with a relatively low absolute value of the voltage value.

[0031] Also, in the above plasma processing apparatus, the separation distance between the gas blowing unit and the base material before performing the spraying of the plasma-containing gas may be 2 mm or less.

[0032] From the viewpoint of efficiently spraying the plasma-containing gas onto the base material, it is preferable that the separation distance between the gas blowing unit and the base material is made as small as possible. Here, when the separation distance becomes small, it is considered that the base material and the gas blowing unit are likely to come into contact or approach, and discharge between the base material and the electrode is likely to occur. However, in the above configuration, since discharge between the base material and the electrode is suppressed, it is possible to reduce the separation distance between the gas blowing unit and the base material, for example, to 2 mm or less.

[0033] The above plasma processing apparatus further includes a transfer unit that transfers the base material in the first direction. When the change over time based on the measured value measured by the measurement unit exceeds a predetermined reference mode, the control unit may stop the operation of the transport unit.

[0034] When the conveyance of the base material stagnates, it is preferable to stop the operation of the conveyance unit. Here, it is also conceivable to incorporate a stop mechanism that automatically stops when the conveyance unit detects the stagnation of the base material. However, depending on the state of the stagnant base material, it is also conceivable that the stop mechanism of the conveyance unit does not operate. On the other hand, according to the above configuration, when the control unit changes the operation of the power supply unit, the operation of the conveyance unit is stopped, which is preferable.

Advantages of the Invention

[0035] According to the present invention, there is provided a plasma processing apparatus capable of suppressing discharge between a base material and an electrode caused by contact or approach of the base material to the plasma processing apparatus.

Brief Description of the Drawings

[0036]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13A

Figure 13B

Embodiments for Carrying Out the Invention

[0037] Embodiments of the plasma processing apparatus according to the present invention will be described below with reference to the drawings. Note that the following drawings are schematically illustrated, and the dimensional ratios and numbers on the drawings do not necessarily match the actual dimensional ratios and numbers.

[0038] [First Embodiment] FIG. 1A is a perspective view showing a configuration example of the plasma processing apparatus. Further, FIG. 1B is a cross-sectional view taken along line B-B in FIG. 1A, and is a drawing showing some components in block diagram form. As shown in FIG. 1A, the plasma processing apparatus 1 includes a plasma generation unit 2 and a transport unit 20.

[0039] As shown in FIG. 1B, the plasma generation unit 2 includes a pair of electrodes (3, 4), a gas flow path 7, a gas blowing unit 9, a power supply unit 11, a measurement unit 12, and a control unit 16. As will be described later, the plasma processing apparatus 1 generates a plasma-containing gas G2 from a source gas G1 flowing through the gas flow path 7, and blows the plasma-containing gas G2 onto a substrate M1 to plasma-treat the main surface M1a of the substrate M1. In FIGS. 1A and 1B, an example is shown in which the plasma-containing gas G2 is blown onto a sheet-like substrate M1 conveyed by the conveying unit 20 to perform plasma treatment on the substrate M1. In FIG. 1B, the illustration of the conveying unit 20 is partially omitted.

[0040] In the following figures, an X-Y-Z coordinate system is appropriately referred to and described, where the direction in which the pair of electrodes (3, 4) face each other is the X direction, the direction in which the substrate M1 and the gas blowing unit 9 face each other is the Z direction, and the direction orthogonal to the X direction and the Z direction is the Y direction. The X direction corresponds to the "first direction", and the Y direction corresponds to the "second direction". In this embodiment, the X direction is the conveyance direction of the substrate M1. Typically, the Z direction is the vertical direction.

[0041] In the following description, when distinguishing between positive and negative directions when expressing a direction, it is described with positive and negative signs, such as "+X direction" and "-X direction". When expressing a direction without distinguishing between positive and negative directions, it is simply described as "X direction". That is, in this specification, when simply described as "X direction", both "+X direction" and "-X direction" are included. The same applies to the Y direction and the Z direction.

[0042] In this embodiment, the pair of electrodes (3, 4) face each other in the X direction with a dielectric 5 therebetween (see FIG. 1B). As an example, the pair of electrodes (3, 4) are made of a metal material such as stainless steel, copper, silver, or aluminum. The dielectric 5 is made of ceramics such as aluminum oxide, aluminum nitride, or steatite, for example.

[0043] FIG. 2 is a plan view when the plasma generation unit 2 is viewed in the Z direction. As shown in FIG. 2, the gas flow path 7 is constituted by the gap between the electrode 4 and the dielectric 5. Although not shown, the position of the dielectric 5 is arbitrary as long as it is arranged between the electrode 3 and the electrode 4 in the X direction. For example, the dielectric 5 may be arranged on the +X side surface of the electrode 4, that is, inside the gas flow path 7.

[0044] The raw material gas G1 is passed through the gas flow path 7 from an arbitrary gas supply mechanism 30 (see FIG. 1B). The raw material gas G1 is arbitrary as long as it can generate active species such as radicals by the discharge S1 between the pair of electrodes (3, 4). As an example, the raw material gas G1 is a gas containing one or more selected from the group consisting of nitrogen, helium, and argon. Further, the raw material gas G1 may contain a small amount of oxygen, hydrogen, water, carbon dioxide, or volatile organic substances from the viewpoint of promoting the generation of radicals.

[0045] The power supply unit 11 includes a power supply circuit for converting the voltage supplied from a power source (not shown) into a high-frequency voltage. The power supply unit 11 applies a high-frequency voltage between the electrode 3 and the electrode 4 via the dielectric 5 and the gas flow path 7. For example, the electrode 3 is the high-potential side electrode, and the electrode 4 is the low-potential side (more specifically, the ground side) electrode. By applying the high-frequency voltage, a discharge S1 occurs in the region where the electrode 3 and the electrode 4 face each other.

[0046] As an example, the high-frequency voltage has a frequency of 20 kHz to 150 kHz and a voltage of 3 kV to 20 kV.

[0047] The plasma processing apparatus 1 generates a plasma-containing gas G2 containing active species such as radicals from the raw material gas G1 by applying a high-frequency voltage to the pair of electrodes (3, 4) by the power supply unit 11 to generate a discharge S1.

[0048] The gas blowing unit 9 communicates with the gas flow path 7 and blows out the plasma-containing gas G2 onto the substrate M1. As shown in FIG. 2, the gas blowing unit 9 is composed of an opening 9a having a slit shape with the Y direction as the longitudinal direction. As an example, the length L1 in the Y direction of the opening 9a is set to 360 mm, and the width W1 in the X direction of the opening 9a is set to 1 mm or less.

[0049] From the viewpoint of efficiently blowing the plasma-containing gas G2 onto the substrate M1, the separation distance D1 between the gas blowing unit 9 and the substrate M1 is preferably made as small as possible (see FIG. 1B). As an example, the separation distance D1 is set to 2 mm or less.

[0050] The conveying unit 20 conveys the substrate M1 in a so-called roll-to-roll manner. More specifically, as shown in FIGS. 1A and 1B, the conveying unit 20 includes a plurality of rollers 20a, and the substrate M1 is conveyed in the X direction by the rotation of the rollers 20a.

[0051] As the substrate M1, for example, a film mainly made of a resin material such as polypropylene, polyester, polystyrene, or polyethylene terephthalate can be used. Further, the substrate M1 may be synthetic paper mainly made of the above resin material. Here, the "main material" refers to the material with the highest ratio among the materials constituting the substrate M1.

[0052] By blowing the plasma-containing gas G2 onto the substrate M1, hydrophilic functional groups such as carbonyl groups, carboxy groups, or hydroxyl groups are formed on the main surface M1a of the substrate M1, the main surface M1a is hydrophilized, or the organic substances present on the main surface M1a are decomposed, and the main surface M1a is modified.

[0053] FIG. 3 is a block diagram partially showing the configuration of the plasma generation unit 2. As shown in FIG. 3, the measurement unit 12 includes a temperature sensor 13. As shown in FIGS. 1B and 2, the temperature sensor 13 is disposed in contact with the surface 4a on the -X side of the electrode 4. From the viewpoint of suppressing the influence of the high-frequency voltage applied by the power supply unit 11 on the measurement accuracy of the temperature sensor 13, the temperature sensor 13 is preferably disposed on the electrode 4 on the low-potential side.

[0054] The separation distance D2 in the Z direction between the temperature sensor 13 and the gas blowing unit 9 is set to 20 mm or less (see FIG. 1B). Thereby, the temperature sensor 13 can measure the temperature in the vicinity of the gas blowing unit 9. Further, the temperature sensor 13 measures the temperature over time. Note that "measuring over time" includes not only the case where the temperature sensor 13 continuously measures the temperature, but also measuring the temperature every predetermined elapsed time.

[0055] In the present embodiment, as shown in FIG. 2, one temperature sensor 13 is disposed at the central portion in the Y direction of the electrode 4. However, a plurality of temperature sensors 13 may be arranged in the Y direction, and this example will be described later with reference to the second embodiment.

[0056] Next, the configuration of the control unit 16 and the control of the power supply unit 11 by the control unit 16 will be described. The control unit 16 is a control means for transmitting a control signal to the power supply unit 11, and includes a processor such as a CPU, for example.

[0057] As shown in FIG. 3, the control unit 16 includes a receiving unit 17a, a transmitting unit 17b, a storage unit 18, and an arithmetic unit 19. Further, the control unit 16 is configured to be able to receive a signal d1 including the measured value of the temperature sensor 13 via the receiving unit 17a (see also FIG. 1B).

[0058] Based on the signal d1, the arithmetic unit 19 calculates the temperature change of the measured value of the temperature sensor 13 with respect to a predetermined elapsed time. When the temperature change exceeds a predetermined reference mode, the control unit 16 transmits a signal d2 from the transmission unit 17b to the power supply unit 11 to change the operation of the power supply unit 11. With the signal d2, the control unit 16 may stop the operation of the power supply unit 11, or may reduce the applied voltage by the power supply unit 11.

[0059] In the storage unit 18, as a reference mode, the temperature change with respect to a predetermined elapsed time is stored. As an example, the temperature change according to the reference mode is in the range of 5°C to 20°C with respect to the elapse of 5 seconds. Further, the temperature change may be in the range of 5°C to 10°C. Furthermore, the predetermined elapsed time may be 1 second.

[0060] FIG. 4 is a graph schematically showing the change over time of the temperature measured by the temperature sensor 13. In FIG. 4, when the base material M1 does not contact the gas blowing unit 9 (corresponding to "Case 1"), and at a certain time T2, as described with reference to FIG. 13A, when the base material M1 contacts the gas blowing unit 9 and stagnates (corresponding to "Case 2"), the change over time of each temperature is schematically shown.

[0061] As shown in FIG. 4, in Case 1, from the time T0 when the application of voltage is started, the temperature gradually increases and approaches the equilibrium state with the surrounding atmosphere, and thus asymptotes to the temperature A1. In Case 1, at time T1, it is illustrated as approaching the temperature A1. That is, in Case 1, after time T1, the temperature rise ΔA1 with respect to a predetermined elapsed time ΔT is a relatively small value.

[0062] On the other hand, in Case 2, after the elapse of time T1, at time T2, when the base material M1 contacts the gas blowing unit 9 and stagnates, the temperature rises significantly compared to Case 1. That is, the temperature rise ΔA2 with respect to a predetermined elapsed time ΔT after time T2 in Case 2 is larger than the temperature rise ΔA1 with respect to ΔT in Case 1.

[0063] Therefore, taking the state where the base material M1 is not in contact with the gas blowing portion 9 as the reference mode, when the change over time of the measured value of the temperature sensor 13 exceeds the reference mode, it can be determined that the base material M1 has come into contact with the gas blowing portion 9. More specifically, a temperature rise ΔA1 for a predetermined elapsed time ΔT is set as the reference mode, and when the temperature rise of the measured value of the temperature sensor 13 with respect to the elapsed time ΔT exceeds ΔA1, it can be determined that the base material M1 has come into contact with the gas blowing portion 9.

[0064] That is, the control unit 16 changes the operation of the power supply unit 11 based on the fact that the temperature change with respect to the predetermined elapsed time obtained from the signal d1 is larger than the temperature change stored in the storage unit 18.

[0065] As described above, a method of setting a threshold value in advance for the temperature in the vicinity of the gas blowing portion 9 and determining that the base material M1 has come into contact with the gas blowing portion 9 when the temperature exceeds the threshold value is also conceivable. However, the temperature in the vicinity of the gas blowing portion 9 depends on the input power for generating the plasma-containing gas G2 and the like, and varies depending on the spraying conditions of the plasma-containing gas G2 on the base material M1. For this reason, it is preferable to determine the contact between the base material M1 and the gas blowing portion 9 based on the temperature rise ΔA1 for the predetermined elapsed time ΔT.

[0066] Note that whether the control unit 16 includes the calculation unit 19 is arbitrary. For example, the measurement unit 12 may calculate the temperature rise of the measured value of the temperature sensor 13 with respect to the elapsed time ΔT and transmit it to the control unit 16 as the signal d1.

[0067] Also, the temperature rise ΔA1 for the predetermined elapsed time ΔT may be stored on an arbitrary server. In this case, the control unit 16 may be configured to be able to read out the temperature rise ΔA1 for the predetermined elapsed time ΔT from the server. That is, whether the control unit 16 includes the storage unit 18 is arbitrary.

[0068] [Second Embodiment] Next, regarding the second embodiment of the plasma processing apparatus 1, the differences from the first embodiment will be mainly described. In the following, descriptions of elements common to the first embodiment will be omitted as appropriate.

[0069] FIG. 5 is a drawing showing a configuration example of the second embodiment following FIG. 2. As shown in FIG. 5, in this embodiment, the measurement unit 12 having a plurality of temperature sensors (14a, 14b, 14c) is different from the first embodiment.

[0070] As shown in FIG. 5, the plurality of temperature sensors (14a, 14b, 14c) are arranged in the Y direction. Also, the separation distance D2 between the gas blowing unit 9 and each temperature sensor (14a, 14b, 14c) is set to 20 mm or less as in the first embodiment (see also FIG. 1B). That is, each of the temperature sensors (14a, 14b, 14c) can measure the temperature in the vicinity of the gas blowing unit 9.

[0071] FIG. 6 is a graph schematically showing the change over time of the temperature measured by the temperature sensors (14a, 14b, 14c). In FIG. 6, at time T3, as described with reference to FIG. 13A, the change over time of the temperature measured by each of the temperature sensors (14a, 14b, 14c) when the substrate M1 contacts and stagnates at the gas blowing unit 9 is schematically shown.

[0072] As shown in Fig. 6, when the base material M1 is not in contact with the gas blowing portion 9, in any of the temperature sensors (14a, 14b, 14c), the temperature gradually rises from the time T0 when the voltage application starts, and approaches the ambient atmosphere to asymptotically approach the temperature A3. Here, as shown in Fig. 5, since the temperature sensors 14a and 14c are arranged at both ends in the Y direction of the gas blowing portion 9, they are more susceptible to the influence of the ambient atmosphere than the central portion where the temperature sensor 14b is arranged. For this reason, the temperatures of the temperature sensors 14a and 14c are lower than the temperature of the temperature sensor 14b. In this embodiment, since the temperature sensors 14a and 14c are arranged at positions that are substantially symmetric with respect to each other in the Y direction, the respective temperatures of the temperature sensors 14a and 14c are approximately equal.

[0073] That is, in the period from time T0 to time T3, it is assumed that the temperature difference a1 between the temperature sensor 14a or the temperature sensor 14c and the temperature sensor 14b becomes substantially constant.

[0074] On the other hand, at time T3, when the base material M1 contacts and stagnates at the gas blowing portion 9 (see also Fig. 13A), the plasma-containing gas G2 is locally blown onto the base material M1, causing the temperature in the temperature sensors (14a, 14b, 14c) to rise. In particular, as shown in Fig. 13A, when the base material M1 contacts the gas blowing portion 9 at the central portion in the Y direction, the temperature of the temperature sensor 14b rises significantly. That is, as shown in Fig. 6, the temperature difference a2 between the temperature sensor 14b and the temperature sensor 14a, and the temperature difference a3 between the temperature sensor 14b and the temperature sensor 14c become larger than the temperature difference a1 before the base material M1 stagnates.

[0075] Therefore, for example, a predetermined temperature difference a1 is set for the temperature difference between the temperature sensor 14b and the temperature sensor 14a. When the temperature difference between the temperature sensor 14b and the temperature sensor 14a exceeds the temperature difference a1 over time, it can be determined that the base material M1 has come into contact with the gas blowing portion 9 and has stagnated. Similarly, a predetermined temperature difference as a reference mode may be set for the temperature difference between the temperature sensor 14b and the temperature sensor 14c.

[0076] As an example, the temperature difference a1 may be in the range of 5°C to 20°C, or may be in the range of 5°C to 10°C. The predetermined temperature difference as a reference mode is appropriately adjusted in view of the heat capacity of the plasma generation unit 2 and the like.

[0077] In addition, a reference mode may be set for the temperature difference between the temperature sensor 14a and the temperature sensor 14c. As shown in FIG. 6, when the base material M1 does not contact the gas blowing portion 9, the temperature difference between the temperature sensor 14a and the temperature sensor 14c becomes small. However, when the base material M1 contacts the gas blowing portion 9, it is assumed that the temperature difference between the temperature sensor 14a and the temperature sensor 14c increases according to the location where the base material M1 contacts. Therefore, it is also possible to determine that the base material M1 has stagnated based on the temperature difference between the temperature sensor 14a and the temperature sensor 14c.

[0078] That is, with the state where the base material M1 is not in contact with the gas blowing portion 9 as the reference mode, when the temperature difference in a predetermined combination extracted from the temperature sensors (14a, 14b, 14c) exceeds the reference mode set for the predetermined combination, it can be determined that the base material M1 has contacted the gas blowing portion 9.

[0079] From the viewpoint of facilitating the comparison between the temperature difference in the predetermined combination and the temperature difference set as the reference mode, it is preferable that the predetermined combination includes the temperature sensor indicating the maximum temperature among the temperature sensors (14a, 14b, 14c).

[0080] FIG. 7 is a block diagram partially showing the configuration of the plasma generation unit 2, following FIG. 3. As shown in FIG. 7, the receiving unit 17a receives a signal d3 including the measured values of the temperature sensors (14a, 14b, 14c). Further, the storage unit 18 stores the reference temperature difference in a predetermined combination among the temperature sensors (14a, 14b, 14c). The storage unit 18 may store the reference temperature difference for each of a plurality of combinations.

[0081] Then, the calculation unit 19 calculates the temperature difference in a predetermined combination based on the measured values of the temperature sensors (14a, 14b, 14c). And when the temperature difference is larger than the reference temperature difference set for the predetermined combination, the control unit 16 transmits a signal d2 to the power supply unit 11 from the transmission unit 17b to change the operation of the power supply unit 11.

[0082] Note that as described in the section of the first embodiment, whether the control unit 16 includes the storage unit 18 and the calculation unit 19 is arbitrary.

[0083] In the above, the measurement unit 12 has been described as having three temperature sensors (14a, 14b, 14c), but the number of temperature sensors is not limited.

[0084] Also, in the above, it has been described that the control unit 16 controls the power supply unit 11 based on the change over time of the temperature difference in a predetermined combination among the temperature sensors (14a, 14b, 14c). However, similar to that described with reference to FIG. 4, a temperature change with respect to a predetermined elapsed time ΔT may be set for each temperature of the plurality of temperature sensors (14a, 14b, 14c), and the control unit 16 may control the operation of the power supply unit 11 based on the change over time of each temperature of the plurality of temperature sensors (14a, 14b, 14c).

[0085] [Third Embodiment] Next, the third embodiment of the plasma processing apparatus 1 will be described, centering on the parts different from the first embodiment. In the following, descriptions of elements common to the first embodiment will be omitted as appropriate.

[0086] FIG. 8 is a cross-sectional view showing a configuration example of the third embodiment, following FIG. 1B. As shown in FIG. 8, in this embodiment, the difference from the first embodiment is that the measurement unit 12 has a pressure sensor 15.

[0087] The pressure sensor 15 is configured to be able to measure the pressure in the gas flow path 7. Note that the pressure sensor 15 can be arranged at any position as long as it can measure the pressure in the gas flow path 7.

[0088] When the substrate M1 comes into contact with and stagnates at the gas blowing portion 9, a part of the gas blowing portion 9 is blocked, so it is considered that the pressure in the gas flow path 7 increases. Therefore, it is considered that the contact of the substrate M1 can be determined based on this pressure.

[0089] Regarding this point, the inventor actually confirmed the change in the pressure in the gas flow path 7 by blocking a partial region of the opening 9a constituting the gas blowing portion 9 with a shielding object. Note that an insulator was used as the shielding object from the viewpoint of suppressing the influence on the discharge S1 between the pair of electrodes (3, 4).

[0090] Table 1 below shows the pressure in the gas flow path 7 when the opening 9a is blocked with a shielding object. In Table 1, the case where no shielding object is arranged is set to 0%, and the ratio of the shielding object to the opening 9a is shown as the shielding rate. The pressure shown in Table 1 corresponds to the average value of the pressure measured while the opening 9a was shielded for a predetermined time.

Table 1

[0091] According to Table 1, it can be understood that the pressure in the gas flow path 7 increases when a part of the opening 9a is blocked. That is, it is possible to determine the contact between the substrate M1 and the gas blowing portion 9 based on the change in the pressure over time.

[0092] FIG. 9 is a graph schematically showing the change over time of the pressure measured by the pressure sensor 15. In FIG. 9, at a certain time T4, as described with reference to FIG. 13A, the change over time of the pressure when the base material M1 contacts and stagnates at the gas blowing portion 9 is schematically shown.

[0093] As shown in FIG. 9, when the base material M1 is not in contact with the gas blowing portion 9, the pressure in the gas flow path 7 is substantially constant at the pressure P1. That is, the change in pressure ΔP1 (not shown for convenience) with respect to a predetermined elapsed time ΔT during the period from time T0 to time T4 is small. On the other hand, as described with reference to FIG. 13A, when the base material M1 contacts and stagnates at the gas blowing portion 9, at least a part of the gas blowing portion 9 is blocked. As a result, as shown in FIG. 9, the pressure in the gas flow path 7 rises to the pressure P2.

[0094] That is, when the base material M1 contacts and stagnates at the gas blowing portion 9, the change in pressure ΔP2 with respect to a predetermined elapsed time ΔT becomes significantly larger than the change in pressure ΔP1 with respect to the elapsed time ΔT during the period from time T0 to time T4. Therefore, by setting the pressure change with respect to a predetermined elapsed time ΔT as ΔP1 as a reference mode, when the pressure change of the measured value of the pressure sensor 15 with respect to the elapsed time ΔT exceeds ΔP1, it can be determined that the base material M1 has contacted the gas blowing portion 9.

[0095] As an example, the predetermined elapsed time ΔT is 1 second, and ΔP1 is 10 kPa or less, preferably 5 kPa or less.

[0096] As described above, a method of setting a threshold value in advance for the pressure in the gas flow path 7 and determining that the base material M1 has contacted the gas blowing portion 9 when the pressure exceeds the threshold value is also conceivable. However, the pressure in the gas flow path 7 depends on the flow rates of the raw material gas G1 and the plasma-containing gas G2, etc., and varies depending on the spraying conditions of the plasma-containing gas G2 on the base material M1. For this reason, it is preferable to judge the contact between the base material M1 and the gas blowing portion 9 based on the pressure change ΔP1 with respect to a predetermined elapsed time ΔT.

[0097] As shown in FIG. 8, the control unit 16 receives a signal d4 including the measured value of the pressure sensor 15. When the change over time of the pressure in the gas flow path 7 exceeds ΔP, the control unit 16 transmits a signal d2 to the power supply unit 11 to change the operation of the power supply unit 11.

[0098] [Alternative Embodiment] 〈1〉 Each embodiment can be realized in combination. For example, in the first embodiment, the measurement unit 12 may have a pressure sensor 15 that measures the pressure in the gas flow path 7 in addition to the temperature sensor 13.

[0099] FIG. 10 is a block diagram partially showing the configuration of the plasma processing apparatus 1 according to another configuration example following FIG. 3. As shown in FIG. 10, the measurement unit 12 may have a temperature sensor 14 and a pressure sensor 15, and the control unit 16 may be configured to be able to receive the measured values of the temperature sensor 14 and the pressure sensor 15 respectively.

[0100] According to the example of FIG. 10, when the change over time of either the temperature near the gas blowing unit 9 or the pressure in the gas flow path 7 exceeds a predetermined reference mode, the control unit 16 changes the operation of the power supply unit 11. For this reason, the contact of the base material M1 with respect to the gas blowing unit 9 can be determined with higher accuracy, and the occurrence of the discharge S10 between the base material M1 and the electrode 3 can be more strongly suppressed.

[0101] Similarly, in the second embodiment, the measurement unit 12 may have a pressure sensor 15 that measures the pressure in the gas flow path 7 in addition to the plurality of temperature sensors (14a, 14b, 14c). The control unit 16 may change the operation of the power supply unit 11 based on the measured values of the plurality of temperature sensors (14a, 14b, 14c) or the pressure sensor 15.

[0102] 〈2〉 FIG. 11 is a block diagram partially showing the configuration of the plasma processing apparatus 1 according to still another configuration example. As shown in FIG. 11, the control unit 16 may be configured to be able to transmit a signal d5 to the transfer unit 20. The signal d5 is a signal for stopping the transfer of the base material M1.

[0103] When the conveyance of the base material M1 stops, it is preferable to stop the operation of the conveyance unit 20. Here, in the conveyance unit 20, for example, when the resistance against the rotation of the roller 20a increases, it is also conceivable to configure the conveyance unit 20 to automatically stop its operation. However, when the base material M1 stops, the resistance against the rotation of the roller 20a does not necessarily increase, and it is also assumed that the roller 20a rotates idly. In view of this point, when the control unit 16 transmits the signal d2 to the power supply unit 11, it is preferable to also transmit the signal d5 to the conveyance unit 20 so that the operation of the conveyance unit 20 is stopped.

[0104] Note that this point is the same in the examples described with reference to FIGS. 7, 8, and 10.

[0105] 〈3〉 FIG. 12 is a perspective view showing a configuration example of another embodiment of the plasma processing apparatus 1. In the above, it has been described that the base material M1 is conveyed in a roll-to-roll manner. However, as shown in FIG. 12, the base material M1 may be conveyed in a state of being placed on a stage 21 such as a conveyor.

[0106] Even when the base material M1 is placed on the stage 21, due to the spraying of the plasma-containing gas G2, the base material M1 may be deformed and come into contact with the gas blowing portion 9. For example, it is assumed that the plasma-containing gas G2 enters a slight gap between the base material M1 and the stage 21 at the end portion e1 in the Y direction of the base material M1. In this case, the base material M1 is deformed so as to be wavy at the end portion e1, but since the separation distance D1 between the base material M1 and the gas blowing portion 9 is small, the base material M1 is likely to come into contact with the gas blowing portion 9 (see FIG. 1B). Then, since the base material M1 is conveyed in the X direction in a state of being in contact with the gas blowing portion 9, as a result, the base material M1 is dragged by the gas blowing portion 9, and it is considered that the base material M1 is sandwiched between the gas blowing portion 9 and the stage 21 and the base material M1 stops.

[0107] Therefore, even when the base material M1 is conveyed by the stage 21, as described in the above embodiment, it is preferable that the control unit 16 is configured to change the operation of the power supply unit 11 based on the change over time in the measurement value of the measurement unit 12.

[0108] Note that even when the base material M1 is in a stationary state and the gas blowing unit 9 of the plasma processing apparatus 1 is conveyed with respect to the base material M1, the same discussion as above is possible.

[0109] 〈4〉 Further, both the base material M1 and the gas blowing unit 9 may be in a stationary state, and the plasma-containing gas G2 may be blown onto the base material M1.

[0110] Even when the base material M1 is in a stationary state, as described with reference to FIG. 12, for example, at the end portion e1 in the Y direction of the base material M1, it is assumed that the plasma-containing gas G2 enters a slight gap between the base material M1 and the stage 21. As a result, the base material M1 is deformed so as to undulate at the end portion e1, and the base material M1 approaches the gas blowing unit 9. In this case, the plasma-containing gas G2 is locally blown onto the base material M1, and the temperature of the base material M1 rises.

[0111] It is also assumed that a part of the gas blowing unit 9 is blocked as the base material M1 approaches the gas blowing unit 9.

[0112] Therefore, even when both the base material M1 and the gas blowing unit 9 are in a stationary state, from the viewpoint of suppressing the generation of the discharge S10, as described in the above embodiment, it is preferable that the control unit 16 is configured to change the operation of the power supply unit 11 based on the change over time in the measurement value of the measurement unit 12.

[0113] That is, in the above embodiment, the plasma processing apparatus 1 has been described as including the transfer unit 20, but whether or not the plasma processing apparatus 1 includes the transfer unit 20 is arbitrary.

[0114] <5> In the above description, a pair of electrodes (3, 4) are described as facing each other with a dielectric 5 therebetween, and a plasma-containing gas G2 is generated by a so-called dielectric barrier discharge method. However, the present invention is not limited to the plasma generation unit 2 having the dielectric 5. That is, the method for generating the plasma-containing gas G2 is not limited to the dielectric barrier discharge method. For example, a voltage is applied between the pair of electrodes (3, 4) with no dielectric 5 disposed therebetween to form a discharge S1 in the gas flow path 7, thereby making it possible to generate the plasma-containing gas G2.

[0115] <6> In the above description, the temperature sensors (13, 14a to 14c) are described as being disposed on the low-potential side electrode 3. However, the temperature sensors (13, 14a to 14c) can be disposed at any position as long as they can measure the temperature in the vicinity of the gas blowing portion 9.

[0116] <7> In the above description, the gas blowing portion 9 is described as being composed of an opening 9a having a slit shape with the Y direction as the longitudinal direction. However, the gas blowing portion 9 may be composed of, for example, a plurality of openings arranged in the Y direction. As an example, the plurality of openings are circular.

[0117] <8> The mode of transmission and reception of the signals (d1, d3, d4) emitted by the measurement unit 12 and the signals (d2, d5) emitted by the control unit 16 is arbitrary. These signals may be transmitted and received via wireless communication or via wired communication.

[0118] <9> In the above, the temperature change with respect to a predetermined elapsed time, the temperature difference in a predetermined combination, or the pressure change with respect to a predetermined elapsed time, which are adopted as the reference mode, may be those learned in advance by machine learning.

[0119] <10> The configuration provided in the plasma processing apparatus 1 described above is merely an example, and the present invention is not limited to each of the illustrated configurations.

Description of Reference Numerals

[0120] 1: Plasma processing apparatus 2: Plasma generation unit 3, 4: Electrodes 5: Dielectric 7: Gas flow path 9: Gas ejection part 11: Power supply unit 12: Measurement unit 13: Temperature sensor 14a, 14b, 14c: Temperature sensors 15: Pressure sensor 16: Control unit 17a: Receiver 17b: Transmitter 18: Memory unit 19: Arithmetic unit 20: Conveying unit 20a: Roller 21: Stage 30: Gas supply mechanism 100: Plasma processing apparatus 101: Plasma generation unit 102: Conveying unit 102a: Roller 103, 104: Electrodes 105: Dielectric 107: Gas flow path 109: Gas ejection part 110: Power supply unit G1: Source gas G2: Plasma-containing gas M1: Substrate M1a: Main surface

Claims

1. A plasma processing apparatus that sprays a plasma-containing gas generated by applying a voltage to a raw material gas flowing through a gas flow path onto a substrate to be processed, comprising: A pair of electrodes facing each other in a first direction; A power supply unit that applies a voltage between the pair of electrodes; A gas blowing unit that blows the plasma-containing gas outward; A measuring unit that measures at least one of the temperature near the gas blowing unit and the pressure in the gas flow path; A control unit that changes the operation of the power supply unit when a change over time based on a measurement value measured by the measuring unit shows a change exceeding a predetermined reference mode. The plasma processing apparatus is characterized by comprising the control unit.

2. The plasma processing apparatus according to claim 1, wherein the control unit changes the operation of the power supply unit when an increase value of at least one of the temperature near the gas blowing unit and the pressure in the gas flow path with respect to a predetermined elapsed time exceeds a predetermined value.

3. The measuring unit is arranged near the gas blowing unit and has a plurality of temperature sensors arranged in a plane parallel to the main surface of the substrate and arranged in a second direction orthogonal to the first direction. The plasma processing apparatus according to claim 1, wherein the control unit changes the operation of the power supply unit when a temperature difference between two measurement values extracted from the measurement values measured by the plurality of temperature sensors exceeds a predetermined value over time.

4. The plasma processing apparatus according to any one of claims 1 to 3, wherein the measuring unit has a temperature sensor arranged near the gas blowing unit and a pressure sensor arranged in the gas flow path.

5. The measuring unit has a temperature sensor arranged near the gas blowing unit. The plasma processing apparatus according to any one of claims 1 to 3, wherein the temperature sensor is in contact with the electrode on the low potential side of the pair of electrodes.

6. The plasma processing apparatus according to any one of claims 1 to 3, wherein a separation distance between the gas blowing unit and the substrate before spraying the plasma-containing gas is 2 mm or less.

7. The apparatus further comprises a transport unit that transports the substrate in the first direction. The plasma processing apparatus according to any one of claims 1 to 3, wherein the control unit stops the operation of the transfer unit when a change over time based on the measurement value measured by the measurement unit indicates a change exceeding a predetermined reference mode.

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