Plasma processing apparatus

Abstract

Provided is a plasma processing apparatus capable of suppressing discharge between a substrate and an electrode caused by contact or proximity of the substrate to the plasma processing device.　The plasma processing apparatus sprays plasma-containing gas, which is generated by applying a voltage to raw material gas flowing in a gas flow path, to a substrate to be processed. The plasma processing apparatus comprises: a pair of electrodes facing each other in a first direction; a power supply unit for applying a voltage between the pair of electrodes; a gas blowout part for blowing out the plasma-containing gas toward the outside; a measurement part for measuring at least one of the temperature in the vicinity of the gas blowout part and the pressure in the gas flow path; and a control part for modifying the operation of the power supply unit when a change over time based on a measured value measured by the measurement part indicates a change of an extent such that a predetermined reference mode is exceeded.

Description

Plasma processing equipment

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

[0002] Plasma processing apparatuses are used in the manufacturing processes of plastics, paper, fibers, semiconductors, liquid crystals, films, and the like. In the plasma processing apparatus, a discharge space is formed inside, and a raw material gas is passed through the discharge space, whereby a portion of the raw material gas is converted into plasma. More specifically, the plasma conversion causes the raw material gas to contain active species such as radicals. Hereinafter, gas that is partially converted into plasma will be referred to as a "plasma-containing gas." A plasma processing apparatus is an apparatus that generates a plasma-containing gas and blows it out.

[0003] In recent years, plasma treatment of the surface of a substrate such as paper or film has been performed by spraying a plasma-containing gas onto the substrate. Plasma treatment can, for example, improve the hydrophilicity of the substrate surface or remove organic matter present on the substrate surface. The present applicant has disclosed a plasma treatment apparatus capable of generating a plasma-containing gas and spraying the plasma-containing gas onto a substrate (see, for example, Patent Document 1 below).

[0004] JP 2023-40527 A

[0005] The inventors of the present invention have investigated plasma treatment of substrates and have found that the substrate may be deformed in a wavy manner due to differences in atmospheric pressure caused by the spraying of a plasma-containing gas, thermal stress caused by the temperature distribution within the main surface of the substrate, etc. When the substrate is deformed in a wavy manner, the substrate and the plasma treatment device may come into local proximity. For example, when the substrate is being transported, the deformation of the substrate may cause it to come into contact with the plasma treatment device, resulting in a stagnation in the transport of the substrate.

[0006] Fig. 13A is a perspective view showing, as an example, a state in which the substrate M1 being transported is deformed and comes into contact with the plasma processing apparatus 100, causing the transport of the substrate M1 to stagnate. Fig. 13B is a cross-sectional view taken along line B-B of Fig. 13A, and is a block diagram showing some of the components.

[0007] 13A, the plasma processing apparatus 100 includes a plasma generation unit 101 and a transport unit 102. In Figures 13A and 13B, an XYZ coordinate system is shown in which the direction in which the substrate M1 and the plasma generation unit 101 face each other is the Z direction, and the plane perpendicular to the Z direction is the XY plane.

[0008] 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 the raw material gas G1 flows, and a gas blowing part 109 that blows out the generated plasma-containing gas G2. In FIG. 13B, an example is shown in which a dielectric 105 is disposed between the pair of electrodes (103, 104).

[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 therein and blows the plasma-containing gas toward the substrate M1 in the transport state.

[0010] The substrate M1 may be deformed in a wavy manner due to a difference in air pressure caused by the spraying of the plasma-containing gas G2, etc. As a result, the substrate M1 may come into contact with the plasma processing apparatus 100, and the transport of the substrate M1 may stagnate, as shown in Figures 13A and 13B.

[0011] When the substrate M1 comes into contact with the plasma processing device and is stagnant in the transport state, the plasma-containing gas G2 is blown locally onto the substrate M1, causing the temperature of the substrate M1 to rise and locally soften the substrate M1. Furthermore, the conductivity of the substrate M1 increases (also known as "carbonization"), making it more likely for a discharge S10 to occur between the substrate M1 and the electrode 103. Although not shown in the figure, the discharge S10 can also occur when the substrate M1 approaches the gas blowing section 109 due to deformation of the substrate M1 during plasma processing of a stationary substrate M1.

[0012] If a discharge S10 occurs between the substrate M1 and the electrode 103, the substrate M1 may deteriorate or emit smoke, and therefore it is preferable to suppress the occurrence of the discharge S10. In other words, there is room for improvement in terms of suppressing the discharge S10 when the substrate M1 contacts 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 that can suppress discharge between a substrate and an electrode caused by the substrate coming into contact with or approaching the plasma processing apparatus.

[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 substrate to be processed, and includes: 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 section that blows the plasma-containing gas outward; a measuring section that measures at least one of the temperature near the gas blowing section and the pressure in the gas flow path; and a control section that changes the operation of the power supply unit when a change over time based on the measurement value measured by the measuring section indicates a change that exceeds a predetermined reference pattern.

[0015] 13A and 13B, when the substrate is stopped in contact with the plasma processing device, a large amount of plasma-containing gas is locally sprayed onto the substrate. As a result, the substrate becomes hot, its conductivity increases, and discharge is more likely to occur between the substrate and the electrodes of the plasma processing device. Therefore, when the substrate transport is stopped, it is preferable to change the operation of the power supply unit for generating plasma-containing gas.

[0016] When the substrate becomes hot, the temperature in the vicinity of the gas blowing part that blows out the plasma-containing gas rises. In other words, when the temperature in the vicinity of the gas blowing part rises, there is a high possibility that the substrate has come into contact with the plasma processing device. Therefore, the temperature in the vicinity of the gas blowing part is suitable as an indicator that the substrate has come into contact with the plasma processing device.

[0017] Here, "vicinity of the gas blowing portion" means a distance of 20 mm or less from the gas blowing portion in the direction in which the substrate and the gas blowing portion face each other.

[0018] Furthermore, when the substrate comes into contact with the plasma processing device, the substrate blocks a portion of the gas blowing section. This causes an increase in the pressure of the gas flow path through which the source gas or plasma-containing gas flows. In other words, if the pressure in the gas flow path increases, it is highly likely that the substrate has come into contact with the plasma processing device. Therefore, like the temperature, the pressure in the gas flow path is a suitable indicator of whether the substrate has come into contact with the plasma processing device.

[0019] Therefore, when a change over time based on at least one of the temperature near the gas blowing portion or the pressure in the gas flow path indicates a change that exceeds a predetermined reference state, the control unit changes the operation of the power supply unit, thereby suppressing discharge between the substrate and the electrode caused by contact of the substrate with the plasma processing device. As an example, the reference state can be set based on a state in which the substrate and the plasma processing device are not in contact with each other.

[0020] It is also possible to consider a method in which a threshold value is set in advance for the temperature near the gas blowing portion or the pressure in the gas flow path, and when the temperature or pressure exceeds the threshold value, it is determined that the substrate has come into contact with the plasma processing device. However, both the temperature and the pressure vary depending on the conditions for blowing the plasma-containing gas onto the substrate.

[0021] For example, the temperature near the gas blowout section 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 blowout section, a situation may occur in which the substrate does not contact the plasma processing device even though the temperature exceeds the threshold value. Furthermore, the pressure in the gas flow path depends on the flow rates of the source gas and the plasma-containing gas. Therefore, as with the discussion of the temperature near the gas blowout section, even if a threshold value is set for the pressure in the gas flow path, it is considered that the proximity of the substrate to the plasma processing device cannot be detected accurately.

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

[0023] In addition, the above description has been given using an example in which a substrate in a transported state comes into contact with a plasma treatment device. However, even when both the substrate and the plasma treatment device are stationary and the substrate is plasma-treated, the substrate may be deformed by the blowing of plasma-containing gas, causing the substrate to approach the plasma treatment device. Even in this case, the same discussion as above can be applied to the point that the approach of the substrate to the plasma treatment device can be determined based on the temperature near the gas blowing section or the pressure in the gas flow path. In other words, the above configuration is not limited to the example in which a substrate in a transported state is plasma-treated. Specific examples will be described later.

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

[0025] As mentioned above, it is difficult to determine whether the substrate has come into contact with the plasma processing device by setting a predetermined threshold value for the temperature or pressure. In contrast, in the above configuration, the control unit changes the operation of the power supply unit depending on the increase in the temperature or pressure over a predetermined elapsed time. As will be described in detail later, when the substrate is not in contact with the plasma processing device, the increase in the temperature or pressure over a predetermined elapsed time is relatively small. Therefore, it is possible to determine whether the substrate has come into contact with the plasma processing device based on the increase in the temperature or pressure.

[0026] Furthermore, in the above plasma processing apparatus, the measurement 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 in a second direction perpendicular to the first direction, and the control unit may change 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.

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

[0028] According to the above configuration, when either the temperature near the gas blowing part or the pressure in the gas flow path shows a change that exceeds a predetermined standard, the operation of the power supply unit is changed, which makes it possible to more accurately determine whether the substrate is in contact with or approaching the gas blowing part and more effectively suppress the occurrence of discharge between the substrate and the electrode.

[0029] In the above plasma processing apparatus, the measurement unit may have a temperature sensor disposed near the gas blowout unit, and the temperature sensor may be in contact with the electrode of the pair of electrodes that has a lower potential.

[0030] The above configuration is advantageous in that it suppresses the effect of the high-frequency voltage applied by the power supply unit to the pair of electrodes on the measurement accuracy of the temperature sensor. Note that the "low-potential electrode" refers to the electrode with a relatively low absolute value of the voltage value.

[0031] In the plasma processing apparatus, the distance between the gas blowing portion and the substrate before the plasma-containing gas is blown may be 2 mm or less.

[0032] From the viewpoint of efficiently blowing the plasma-containing gas onto the substrate, it is preferable that the distance between the gas blowing part and the substrate is as small as possible. Here, it is considered that if the distance is small, the substrate and the gas blowing part are likely to come into contact or approach each other, and discharge between the substrate and the electrode is likely to occur. However, in the above configuration, since discharge between the substrate and the electrode is suppressed, the distance between the gas blowing part and the substrate can be made small, for example, 2 mm or less.

[0033] The plasma processing apparatus may further include a transport unit that transports the substrate in the first direction, and the control unit may stop operation of the transport unit when a change over time based on the measurement value measured by the measurement unit indicates a change that exceeds a predetermined reference pattern.

[0034] When the transport of the substrate stagnates, it is preferable to stop the operation of the transport unit. Here, it is conceivable to incorporate a stop mechanism into the transport unit that automatically stops the transport unit when it detects that the substrate is stagnating. However, depending on the nature of the stagnated substrate, it is conceivable that the stop mechanism of the transport unit will not operate. In contrast, the above configuration is preferable because the operation of the transport unit is stopped when the control unit changes the operation of the power supply unit.

[0035] According to the present invention, a plasma processing apparatus is provided that can suppress discharge between a substrate and an electrode due to contact or proximity of the substrate to the plasma processing apparatus.

[0036] 1B is a cross-sectional view showing an example of the configuration of a plasma processing apparatus; FIG. 1C is a cross-sectional view taken along line B-B in FIG. 1A, showing some components in a block diagram; FIG. 1D is a plan view of the plasma generation unit as viewed in the Z direction; FIG. 1E is a block diagram showing a portion of the configuration of the plasma generation unit; FIG. 1F is a graph showing a schematic change in temperature measured by a temperature sensor over time; FIG. 1G is a diagram showing an example of the configuration of a second embodiment, following FIG. 2; FIG. 1G is a graph showing a schematic change in temperature measured by a temperature sensor over time; FIG. 1H is a block diagram showing a portion of the configuration of a plasma generation unit, following FIG. 1I; FIG. 1H is a cross-sectional view showing an example of the configuration of a third embodiment, following FIG. 1B; FIG. 1H is a graph showing a schematic change in pressure measured by a pressure sensor over time; FIG. 1H is a block diagram showing a portion of the configuration of a plasma processing apparatus according to another example of the configuration; FIG. 1H is a block diagram showing a portion of the configuration of a plasma processing apparatus according to yet another example of the configuration; FIG. 1I is a perspective view showing a configuration example of another embodiment of a plasma processing apparatus; FIG. 1J is a perspective view showing a state in which a substrate being transported is deformed and comes into contact with the plasma processing apparatus, causing transport of the substrate to stagnate. 13B is a cross-sectional view taken along the line BB in FIG. 13A, showing some components in a block diagram.

[0037] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma processing apparatus according to an embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the drawings are schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily correspond to the actual dimensional ratios and numbers.

[0038] [First embodiment] Fig. 1A is a perspective view showing an example of the configuration of a plasma processing apparatus. Fig. 1B is a cross-sectional view taken along line B-B in Fig. 1A, showing some of the components in a block diagram. 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 blowout unit 9, a power supply unit 11, a measurement unit 12, and a control unit 16. As described below, the plasma processing apparatus 1 generates a plasma-containing gas G2 from a raw material gas G1 flowing through the gas flow path 7, and sprays the plasma-containing gas G2 onto a substrate M1 to plasma-treat the main surface M1a of the substrate M1. FIGS. 1A and 1B show an example of plasma-treating the substrate M1 by spraying the plasma-containing gas G2 onto a sheet-shaped substrate M1 transported by a transport unit 20. Note that the transport unit 20 is partially omitted from FIG. 1B .

[0040] In the following drawings, the explanation will be made with appropriate reference to an X-Y-Z coordinate system, in which 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 section 9 face each other is the Z direction, and the direction perpendicular 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 transport direction of the substrate M1. Typically, the Z direction is the vertical direction.

[0041] In the following description, when a direction needs to be distinguished between positive and negative directions, it is described with a positive or negative sign, such as "+X direction" and "-X direction." When a direction is described without distinguishing between positive and negative directions, it is simply described as "X direction." In other words, in this specification, when simply referring to "X direction," it includes both "+X direction" and "-X direction." 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 via the dielectric 5 (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 a ceramic material such as aluminum oxide, aluminum nitride, or steatite.

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

[0044] A source gas G1 is passed through the gas flow path 7 from an optional gas supply mechanism 30 (see FIG. 1B ). The source gas G1 may be any gas 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 source gas G1 is a gas containing one or more elements selected from the group consisting of nitrogen, helium, and argon. Furthermore, the source gas G1 may contain trace amounts of oxygen, hydrogen, water, carbon dioxide, or volatile organic compounds in order to promote the generation of radicals.

[0045] The power supply unit 11 includes a power supply circuit for converting a 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 electrode, and the electrode 4 is the low-potential electrode (more specifically, the ground side). When the high-frequency voltage is applied, a discharge S1 is generated in the region where the electrode 3 and the electrode 4 face each other.

[0046] As an example, the high frequency voltage is set to 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 discharge S1 by applying a high-frequency voltage to a pair of electrodes (3, 4) using a power supply unit 11, and generates a plasma-containing gas G2 containing active species such as radicals from a raw material gas G1.

[0048] The gas blowing section 9 is connected to 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 section 9 is configured with a slit-shaped opening 9a whose longitudinal direction is the Y direction. As an example, the length L1 of the opening 9a in the Y direction is 360 mm, and the width W1 of the opening 9a in the X direction is 1 mm or less.

[0049] In order to efficiently blow the plasma-containing gas G2 onto the substrate M1, it is preferable to make the distance D1 between the gas blowout part 9 and the substrate M1 as small as possible (see FIG. 1B). For example, the distance D1 is set to 2 mm or less.

[0050] 1A and 1B, the transport unit 20 includes a plurality of rollers 20a, and transports the substrate M1 in the X direction by rotation of the rollers 20a.

[0051] The substrate M1 may be a film primarily made of a resin material such as polypropylene, polyester, polystyrene, or polyethylene terephthalate. The substrate M1 may also be synthetic paper primarily made of the above-mentioned resin material. The term "primary material" used here refers to the material that accounts for the largest proportion of the materials constituting the substrate M1.

[0052] By spraying the plasma-containing gas G2 onto the substrate M1, hydrophilic functional groups such as carbonyl groups, carboxyl groups, or hydroxyl groups are formed on the main surface M1a of the substrate M1, making the main surface M1a hydrophilic, and organic matter present on the main surface M1a is decomposed, thereby modifying the main surface M1a.

[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 has a temperature sensor 13. As shown in Fig. 1B and Fig. 2, the temperature sensor 13 is arranged 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, it is preferable that the temperature sensor 13 be arranged on the electrode 4 on the low potential side.

[0054] The distance D2 between the temperature sensor 13 and the gas blowing section 9 in the Z direction is 20 mm or less (see FIG. 1B). This allows the temperature sensor 13 to measure the temperature in the vicinity of the gas blowing section 9. The temperature sensor 13 also measures the temperature over time. Note that "measuring over time" is not limited to the case where the temperature sensor 13 measures the temperature continuously, but also includes measuring the temperature at predetermined intervals.

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

[0056] Next, a description will be given of the configuration of the control unit 16 and the control of the power supply unit 11 by the control unit 16. The control unit 16 is a control means that transmits control signals to the power supply unit 11, and is configured to include a processor such as a CPU.

[0057] 3, the control unit 16 includes a receiving unit 17a, a transmitting unit 17b, a storage unit 18, and a calculation unit 19. The control unit 16 is also configured to receive a signal d1 including a measurement value of the temperature sensor 13 via the receiving unit 17a (see also FIG. 1B).

[0058] The calculation unit 19 calculates the temperature change over a predetermined elapsed time in the value measured by the temperature sensor 13 based on the signal d1. If the temperature change exceeds a predetermined reference value, the control unit 16 sends a signal d2 from the transmission unit 17b to the power supply unit 11 to change the operation of the power supply unit 11. In response to the signal d2, the control unit 16 may stop the operation of the power supply unit 11 or may reduce the voltage applied by the power supply unit 11.

[0059] The storage unit 18 stores a temperature change over a predetermined elapsed time as a reference state. As an example, the temperature change over the reference state is set to be within a range of 5°C to 20°C over the elapsed time of 5 seconds. The temperature change may also be set to be within a range of 5°C to 10°C. Furthermore, the predetermined elapsed time may be set to 1 second.

[0060] Fig. 4 is a graph showing a schematic change over time in the temperature measured by the temperature sensor 13. Fig. 4 shows a schematic change over time in the temperature when the substrate M1 is not in contact with the gas blowing section 9 (corresponding to "Case 1") and when the substrate M1 is in contact with the gas blowing section 9 and stagnates at a certain time T2 as described with reference to Fig. 13A (corresponding to "Case 2").

[0061] 4, in Case 1, the temperature gradually increases from time T0 when the voltage application starts, and approaches a state of equilibrium with the surrounding atmosphere, thereby asymptotically approaching temperature A1. Case 1 is illustrated as asymptotically approaching temperature A1 at time T1. In other words, in Case 1, after time T1, the temperature increase ΔA1 for a given elapsed time ΔT becomes a relatively small value.

[0062] In contrast, in Case 2, after time T1 has elapsed, at time T2, the substrate M1 comes into contact with the gas blowing portion 9 and stagnates, causing a significant rise in temperature compared to Case 1. That is, in Case 2, the temperature rise ΔA2 for a predetermined elapsed time ΔT after time T2 is larger than the temperature rise ΔA1 for ΔT in Case 1.

[0063] Therefore, a state in which the substrate M1 is not in contact with the gas blowing section 9 is set as a reference state, and when the change over time in the measurement value of the temperature sensor 13 exceeds this reference state, it can be determined that the substrate M1 has come into contact with the gas blowing section 9. More specifically, a temperature rise ΔA1 over a predetermined elapsed time ΔT is set as the reference state, and when the temperature rise over the elapsed time ΔT in the measurement value of the temperature sensor 13 exceeds ΔA1, it can be determined that the substrate M1 has come into contact with the gas blowing section 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 over a predetermined elapsed time obtained from the signal d1 is greater than the temperature change stored in the storage unit 18.

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

[0066] It is optional whether the control unit 16 includes the calculation unit 19. For example, the measurement unit 12 may calculate the temperature rise over the elapsed time ΔT measured by the temperature sensor 13 and transmit the result to the control unit 16 as a signal d1.

[0067] The temperature increase 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 the temperature increase ΔA1 for the predetermined elapsed time ΔT from the server. In other words, it is optional whether the control unit 16 includes the storage unit 18.

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

[0069] Fig. 5 is a diagram showing a configuration example of the second embodiment, following Fig. 2. As shown in Fig. 5, this embodiment differs from the first embodiment in that the measurement unit 12 has a plurality of temperature sensors (14a, 14b, 14c).

[0070] The temperature sensors (14a, 14b, 14c) are arranged in the Y direction as shown in Fig. 5. The distance D2 between the gas blowout section 9 and each of the temperature sensors (14a, 14b, 14c) is 20 mm or less, as in the first embodiment (see also Fig. 1B). That is, each of the temperature sensors (14a, 14b, 14c) is capable of measuring the temperature in the vicinity of the gas blowout section 9.

[0071] Fig. 6 is a graph showing a schematic change over time in the temperature measured by the temperature sensors (14a, 14b, 14c). Fig. 6 shows a schematic change over time in the temperature measured by each of the temperature sensors (14a, 14b, 14c) when the substrate M1 comes into contact with the gas blowing section 9 and stagnates thereat at time T3, as described with reference to Fig. 13A.

[0072] As shown in FIG. 6 , when the substrate M1 is not in contact with the gas blowing section 9, the temperature of each of the temperature sensors (14a, 14b, 14c) gradually increases from time T0 when the voltage application starts, and approaches equilibrium with the surrounding atmosphere, gradually approaching temperature A3. Here, as shown in FIG. 5 , temperature sensors 14a and 14c are disposed at both ends of the gas blowing section 9 in the Y direction, and are therefore more susceptible to the surrounding atmosphere than the central portion where temperature sensor 14b is disposed. Therefore, the temperatures at temperature sensors 14a and 14c are lower than the temperature at temperature sensor 14b. In this embodiment, temperature sensors 14a and 14c are disposed at positions approximately symmetrical to each other in the Y direction, and therefore the temperatures at temperature sensors 14a and 14c are approximately equal.

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

[0074] In contrast, at time T3, when the substrate M1 comes into contact with the gas blowing section 9 and stagnates (see also FIG. 13A ), the plasma-containing gas G2 is blown locally onto the substrate M1, causing the temperature at the temperature sensors (14a, 14b, 14c) to rise. In particular, as shown in FIG. 13A , when the substrate M1 comes into contact with the gas blowing section 9 at the center in the Y direction, the temperature at the temperature sensor 14b rises significantly. That is, as shown in FIG. 6 , the temperature difference a2 between the temperature sensors 14b and 14a and the temperature difference a3 between the temperature sensors 14b and 14c become larger than the temperature difference a1 before the substrate M1 stagnates.

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

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

[0077] Furthermore, a reference mode may be set for the temperature difference between temperature sensor 14a and temperature sensor 14c. As shown in Fig. 6, when substrate M1 is not in contact with gas blowing section 9, the temperature difference between temperature sensor 14a and temperature sensor 14c is small. However, when substrate M1 comes into contact with gas blowing section 9, it is expected that the temperature difference between temperature sensor 14a and temperature sensor 14c will increase depending on the location of contact of substrate M1. For this reason, it is also possible to determine that substrate M1 has stagnated based on the temperature difference between temperature sensor 14a and temperature sensor 14c.

[0078] In other words, the state in which the substrate M1 is not in contact with the gas blowing section 9 is taken as the reference state, and if the temperature difference in a specified combination extracted from the temperature sensors (14a, 14b, 14c) exceeds the reference state set for that specified combination, it can be determined that the substrate M1 has come into contact with the gas blowing section 9.

[0079] In addition, from the viewpoint of facilitating comparison of the temperature difference in a specified combination with the temperature difference set as the reference mode, it is preferable that the specified combination includes the temperature sensor that indicates the maximum temperature among the temperature sensors (14a, 14b, 14c).

[0080] 7 is a block diagram partially illustrating the configuration of the plasma generation unit 2, following FIG. 3. As shown in FIG. 7, the receiver 17a receives a signal d3 including the measurement values ​​of each of the temperature sensors (14a, 14b, 14c). The memory 18 stores the reference temperature difference for a predetermined combination of the temperature sensors (14a, 14b, 14c). The memory 18 may store the reference temperature difference for each of multiple combinations.

[0081] The calculation unit 19 calculates the temperature difference for a predetermined combination based on the measured values ​​of the temperature sensors (14a, 14b, 14c). If the calculated temperature difference is greater than a reference temperature difference set for the predetermined combination, the control unit 16 causes the transmission unit 17b to transmit a signal d2 to the power supply unit 11, thereby changing the operation of the power supply unit 11.

[0082] As described in the first embodiment, it is optional whether the control unit 16 includes the storage unit 18 and the calculation unit 19.

[0083] In the above description, 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] In the above description, the control unit 16 controls the power supply unit 11 based on the change over time in the temperature difference between a predetermined combination of the temperature sensors (14a, 14b, 14c). However, as described with reference to Fig. 4, it is also possible to set a temperature change over a predetermined elapsed time ΔT for each temperature of the plurality of temperature sensors (14a, 14b, 14c), and have the control unit 16 control the operation of the power supply unit 11 based on the change over time in the temperature of each of the plurality of temperature sensors (14a, 14b, 14c).

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

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

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

[0088] When the substrate M1 comes into contact with the gas blowing portion 9 and stagnates, it is considered that a part of the gas blowing portion 9 is blocked, and the pressure inside 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 present inventors actually confirmed the change in pressure inside the gas flow path 7 by blocking a part of the opening 9a constituting the gas blowout part 9 with a shield. Note that an insulator was used as the shield 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 inside the gas flow path 7 when the opening 9a is blocked with a shield. In Table 1, the ratio of the shield to the opening 9a is shown as the shielding rate, with the case where no shield is placed being set as 0%. The pressures shown in Table 1 correspond to the average values ​​of the pressure measured while the opening 9a is blocked for a predetermined time.

[0091] It can be seen from Table 1 that blocking a portion of the opening 9a increases the pressure in the gas flow path 7. In other words, it is possible to determine whether the substrate M1 and the gas blowing part 9 are in contact with each other based on the change in the pressure over time.

[0092] Fig. 9 is a graph that schematically shows the change over time in the pressure measured by the pressure sensor 15. Fig. 9 schematically shows the change over time in the pressure when the substrate M1 comes into contact with the gas blowing portion 9 and stagnates at a certain time T4, as described with reference to Fig. 13A.

[0093] As shown in Fig. 9, when the substrate M1 is not in contact with the gas blowing portion 9, the pressure in the gas flow path 7 is substantially constant at pressure P1. In other words, the change in pressure ΔP1 (not shown for convenience) over a predetermined elapsed time ΔT in the period from time T0 to time T4 is small. In contrast, as described with reference to Fig. 13A, when the substrate M1 comes into contact with the gas blowing portion 9 and stagnates, at least a portion 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 pressure P2.

[0094] In other words, when the base material M1 comes into contact with the gas blowing section 9 and stagnates, the change in pressure ΔP2 over a predetermined elapsed time ΔT becomes significantly larger than the change in pressure ΔP1 over the elapsed time ΔT during the period from time T0 to time T4. Therefore, by setting the change in pressure over a predetermined elapsed time ΔT as ΔP1 as a reference mode, it can be determined that the base material M1 has come into contact with the gas blowing section 9 when the change in pressure over the elapsed time ΔT measured by the pressure sensor 15 exceeds ΔP1.

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

[0096] As described above, a method may be considered in which a threshold value is set in advance for the pressure in the gas flow path 7, and when the pressure exceeds the threshold value, it is determined that the substrate M1 has come into contact with the gas blowing portion 9. However, the pressure in the gas flow path 7 depends on the flow rates of the source gas G1 and the plasma-containing gas G2, and varies depending on the conditions for blowing the plasma-containing gas G2 onto the substrate M1. For this reason, it is preferable to determine the contact between the substrate M1 and the gas blowing portion 9 based on a pressure change ΔP1 over a predetermined elapsed time ΔT.

[0097] 8, the control unit 16 receives a signal d4 including a measurement value of the pressure sensor 15. Then, when the change in pressure over time in the gas flow path 7 exceeds ΔP, the control unit 16 sends a signal d2 to the power supply unit 11 to change the operation of the power supply unit 11.

[0098] Other Embodiments <1> The embodiments can be realized in combination. For example, in the first embodiment, the measurement unit 12 may include 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 illustrating 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 measurement values ​​of the temperature sensor 14 and the pressure sensor 15.

[0100] 10 , when a change over time in either the temperature near the gas blowout part 9 or the pressure in the gas flow path 7 exceeds a predetermined reference level, the control part 16 changes the operation of the power supply unit 11. This makes it possible to more accurately determine whether the substrate M1 is in contact with the gas blowout part 9, and more effectively suppress the occurrence of discharge S10 between the substrate M1 and the electrode 3.

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

[0102] 11 is a block diagram partially illustrating the configuration of the plasma processing apparatus 1 according to another configuration example. As shown in FIG. 11, the control unit 16 may be configured to be able to send a signal d5 to the transport unit 20. The signal d5 is a signal to stop transport of the substrate M1.

[0103] When the transport of the substrate M1 stagnates, it is preferable to stop the operation of the transport unit 20. Here, it is also conceivable to configure the transport unit 20 so that, for example, when the resistance to the rotation of the roller 20a increases, the operation of the transport unit 20 automatically stops. However, when the substrate M1 stagnates, the resistance to the rotation of the roller 20a does not necessarily increase, and it is also possible that the roller 20a may spin freely. In view of this, it is preferable that, when the control unit 16 sends the signal d2 to the power supply unit 11, it also sends a signal d5 to the transport unit 20 to stop the operation of the transport unit 20.

[0104] This also applies to the examples described with reference to FIGS. 7, 8, and 10.

[0105] <3> Figure 12 is a perspective view showing a configuration example of another embodiment of the plasma processing apparatus 1. In the above, the substrate M1 has been described as being transported by a roll-to-roll method. However, as shown in Figure 12, the substrate M1 may be transported while being placed on a stage 21 such as a conveyor.

[0106] Even when the substrate M1 is placed on the stage 21, the substrate M1 may be deformed by the blowing of the plasma-containing gas G2 and come into contact with the gas blowing portion 9. For example, it is assumed that the plasma-containing gas G2 may enter a small gap between the substrate M1 and the stage 21 at the end e1 of the substrate M1 in the Y direction. In this case, the substrate M1 is deformed in a wavy manner at the end e1, but the small separation distance D1 between the substrate M1 and the gas blowing portion 9 makes it easy for the substrate M1 to come into contact with the gas blowing portion 9 (see FIG. 1B ). Furthermore, since the substrate M1 is transported in the X direction while in contact with the gas blowing portion 9, the substrate M1 is dragged by the gas blowing portion 9, and as a result, the substrate M1 becomes sandwiched between the gas blowing portion 9 and the stage 21, and the substrate M1 is thought to stagnate.

[0107] For this reason, even when the substrate M1 is transported by the stage 21, it is preferable that the control unit 16 be configured to change the operation of the power supply unit 11 based on changes over time in the measurement values ​​of the measurement unit 12, as described in the above embodiment.

[0108] The same discussion as above can be made even in the case where the substrate M1 is in a stationary state and the gas blowing unit 9 of the plasma processing apparatus 1 is transported relative to the substrate M1.

[0109] <4> Furthermore, the substrate M1 and the gas blowing unit 9 may both be stationary, and the plasma-containing gas G2 may be blown onto the substrate M1.

[0110] 12, even when the substrate M1 is in a stationary state, it is assumed that the plasma-containing gas G2 may enter a small gap between the substrate M1 and the stage 21, for example, at the end e1 of the substrate M1 in the Y direction. As a result, the substrate M1 is deformed in a wavy manner at the end e1, and the substrate M1 approaches the gas blowing section 9. In this case, the plasma-containing gas G2 is blown locally onto the substrate M1, causing the temperature of the substrate M1 to rise.

[0111] It is also conceivable that the substrate M1 approaches the gas blowing portion 9, causing a portion of the gas blowing portion 9 to be blocked.

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

[0113] That is, in the above embodiment, the plasma processing apparatus 1 is described as including the transport unit 20, but it is optional whether or not the plasma processing apparatus 1 includes the transport unit 20.

[0114] <5> In the above description, the pair of electrodes (3, 4) are opposed to each other via the dielectric 5, and the plasma-containing gas G2 is generated by a so-called dielectric barrier discharge method. However, the present invention is not limited to whether the plasma generation unit 2 has the dielectric 5. In other words, the method for generating the plasma-containing gas G2 is not limited to the dielectric barrier discharge method. For example, it is also possible to generate the plasma-containing gas G2 by applying a voltage between the pair of electrodes (3, 4) without the dielectric 5 being disposed between the electrodes (3, 4) to form a discharge S1 in the gas flow path 7.

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

[0116] <7> In the above description, the gas blowing section 9 has been described as being configured with a slit-shaped opening 9a with the Y direction as the longitudinal direction. However, the gas blowing section 9 may be configured with a plurality of openings arranged in the Y direction, for example. As an example, the plurality of openings are circular.

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

[0118] <9> In the above, the temperature change over a predetermined elapsed time, the temperature difference in a predetermined combination, or the pressure change over a predetermined elapsed time that is adopted as the reference mode may be learned in advance by machine learning.

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

[0120] 1: Plasma processing apparatus 2: Plasma generation unit 3, 4: Electrode 5: Dielectric 7: Gas flow path 9: Gas blowing section 11: Power supply unit 12: Measurement section 13: Temperature sensor 14a, 14b, 14c: Temperature sensor 15: Pressure sensor 16: Control section 17a: Receiving section 17b: Transmitting section 18: Memory section 19: Calculation section 20: Transport unit 20a: Roller 21: Stage 30: Gas supply mechanism 100: Plasma processing apparatus 101: Plasma generation unit 102: Transport unit 102a: Roller 103, 104: Electrode 105: Dielectric 107: Gas flow path 109: Gas blowing section 110: Power supply unit G1: Raw material 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, the plasma processing apparatus 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 measurement unit that measures at least one of the temperature near the gas blowing unit and the pressure in the gas flow path; and 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 measurement unit indicates a change exceeding a predetermined reference mode.

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 measurement unit has a plurality of temperature sensors arranged near the gas blowing unit and arranged in a plane parallel to the main surface of the substrate and in a second direction orthogonal to the first direction. 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 as time elapses. The plasma processing apparatus according to claim 1.

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

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

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

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

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