JP4519695B2 - Thin film manufacturing apparatus and thin film manufacturing method - Google Patents

Description

  The present invention relates to a thin film manufacturing apparatus and a thin film manufacturing method.

  2. Description of the Related Art In a thin film manufacturing apparatus that manufactures a thin film used in an amorphous solar cell, a microcrystalline solar cell, a TFT (Thin Film Transistor), and the like, an area of a substrate is being increased from the viewpoint of improving production efficiency. When forming such a large-area substrate (example: 1 m × 1 m or more), a method using high-frequency plasma is useful (for example, JP-A-2002-322563). In that case, it is necessary to use high-frequency high power during film formation or self-cleaning.

  When supplying high-frequency large power to the discharge electrode, there is a flexible cable as a power transmission path. In the flexible cable, an internal insulator is divided into a plurality of small insulators so that the flexible cable can be bent. Since the space between the insulators varies depending on the bending state of the flexible cable, the characteristic impedance varies depending on the bending state even though the same flexible cable is used. For this reason, loss may occur during power feeding, and the power feeding transmission path may be unnecessarily heated. In that case, changes in electrical characteristics and physical damage frequently occur in the power transmission line, leading to deterioration in film thickness distribution during film formation, an increase in self-cleaning time, and a decrease in productivity such as stoppage of the production machine. There is a demand for a thin film manufacturing apparatus that can suppress a temperature rise in a power transmission line and can stably supply high-frequency high power.

  In addition, since the temperature of the discharge electrode is increased by high-power and high-frequency plasma, the substrate on the counter electrode is affected by the influence, and the substrate temperature may increase or the substrate temperature distribution may be increased. In that case, substrate warpage occurs, and a waiting time is required until the substrate warpage is reduced, leading to a decrease in productivity. A thin-film manufacturing apparatus that can stabilize the temperature of the discharge electrode and stabilize the temperature of the substrate facing the discharge electrode is desired.

JP 2002-322563 A

  Therefore, an object of the present invention is to provide a thin film manufacturing apparatus and a thin film manufacturing method capable of manufacturing a solar cell without reducing productivity even when a large-area substrate is used.

  Another object of the present invention is to provide a thin film manufacturing apparatus and a thin film manufacturing method capable of stably supplying high-frequency high power.

  Still another object of the present invention is to provide a thin film manufacturing apparatus and a thin film manufacturing method having a power feeding structure that does not change electrical characteristics or physically damage even with high frequency high power.

  Another object of the present invention is to provide a thin film manufacturing apparatus and a thin film manufacturing method capable of stabilizing a temperature distribution of a substrate and performing a desired film formation.

  Still another object of the present invention is to provide a thin film manufacturing apparatus and a thin film manufacturing method capable of stabilizing the temperature of the discharge electrode and suppressing the influence on the substrate.

  Hereinafter, means for solving the problem will be described using the numbers and symbols used in the best mode for carrying out the invention. These numbers and symbols are added in parentheses in order to clarify the correspondence between the description of the claims and the best mode for carrying out the invention. However, these numbers and symbols should not be used for interpreting the technical scope of the invention described in the claims.

Therefore, in order to solve the above-described problem, the present invention is capable of matching the impedance on the output side and transmitting the supplied first power, and one end connected to the first matcher, A first feeding transmission line that mediates transmission of the first power, a second matching unit that can match the impedance on the output side and transmits the supplied second power, and one end connected to the second matching unit; Connected to the second feeding transmission path that mediates transmission of the second power, the other end of the first feeding transmission path, and the other end of the second feeding transmission path, and supplied with the first power and the second power A discharge electrode, and a counter electrode opposite to the discharge electrode, wherein the first power transmission path includes a first heat medium supply pipe through which a heat medium passes, and the discharge electrode includes the heat medium. A heat medium flow pipe passing therethrough, wherein the second power transmission line is a second through which the heat medium passes. A medium supply pipe, wherein the first matching unit includes a first heat medium supply unit that supplies the heat medium to the first heat medium supply pipe, and the second matching unit includes the second heat medium supply pipe. A second heat medium supply section for receiving the heat medium from the first power transmission path and the second power transmission path, each of which is separated from a hard tubular outer conductor and an inner peripheral surface of the outer conductor, An insulator provided in a tubular shape inside the outer conductor; and an inner conductor provided inside the insulator apart from an inner peripheral surface of the insulator; and the first heat medium supply pipe and Each of the second heat medium supply pipes provides a thin film manufacturing apparatus provided inside the inner conductor.

The present invention is also capable of matching the impedance on the output side, transmitting the supplied first power, and one end connected to the first matcher, and mediating transmission of the first power. A first feeding transmission line, a second matching unit capable of matching the impedance on the output side and transmitting the supplied second power, and one end connected to the second matching unit and mediating transmission of the second power A second feed transmission line, a discharge electrode connected to the other end of the first feed transmission path and the other end of the second feed transmission path, to which the first power and the second power are supplied, and the discharge An opposing electrode facing the electrode, wherein the first feeding transmission path includes a first heat medium supply pipe that passes a heat medium, and the discharge electrode includes a heat medium flow pipe that passes the heat medium, The second power transmission path includes a second heat medium supply pipe through which the heat medium passes, The combiner includes a first heat medium supply unit that supplies the heat medium to the first heat medium supply pipe, and the second matching unit receives a second heat that receives the heat medium from the second heat medium supply pipe. A medium supply unit, wherein each of the first feeding transmission path and the second feeding transmission path is provided in a tubular shape inside the outer conductor, apart from a hard tubular outer conductor and an inner peripheral surface of the outer conductor. And an inner conductor provided in the insulator away from the inner peripheral surface of the insulator, wherein the inner conductor includes the first heat medium supply pipe and the second heat conductor. A thin film manufacturing apparatus that functions as a medium supply pipe is provided.

In the above-described thin film manufacturing apparatus of the present invention, it is preferable that the distance between the outer conductor and the insulator and the distance between the insulator and the inner conductor are 0.1 mm or more and 1 mm or less.

The present invention also includes: (a) supplying a source gas between the discharge electrode and the counter electrode holding the substrate; and (b1) matching the impedance on the output side of the first matching unit, Supplying a first power to the discharge electrode via a hard tubular outer conductor of a first feeding transmission line connected to the output side of the first matcher; (b2) impedance of the output side of the second matcher Providing a second power to the discharge electrode through a rigid tubular outer conductor of a second feeding transmission line connected to the output side of the second matching unit; and (c) the first feeding. A heat medium flow pipe provided in the discharge electrode from a first heat medium supply pipe provided through an insulator provided inside the outer conductor of the transmission line and separated from the inner peripheral surface of the outer conductor. Supply a heat medium to the outside of the second power transmission line Receiving a heat medium from the heat medium flow pipe by a second heat medium supply pipe provided via an insulator provided inside the partial conductor and separated from the inner peripheral surface of the outer conductor. A thin film manufacturing method is provided.

In the thin film manufacturing method of the present invention described above, the step (c) includes: (c1) a step of measuring the temperature of the discharge electrode; and (c2) the temperature of the heat medium and the heat medium based on the measurement result. It is preferable to include a step of controlling at least one of the flow rates and supplying the flow rate to the heat medium flow pipe .

  According to the present invention, high-frequency high power can be stably fed without changing the electrical characteristics of the feeding structure or physically damaging it. The temperature of the discharge electrode can be stabilized to suppress the influence on the substrate, the temperature distribution of the substrate can be stabilized, and desired film formation can be performed. And productivity of thin film manufacture can be improved.

Hereinafter, embodiments of the thin film manufacturing apparatus of the present invention will be described with reference to the accompanying drawings.
First, the configuration of the embodiment of the thin film manufacturing apparatus of the present invention will be described. FIG. 1 is a conceptual diagram showing a configuration of an embodiment of a thin film manufacturing apparatus of the present invention. It is the figure seen from the side of a thin film manufacturing apparatus. The thin film manufacturing apparatus 1 includes a film forming chamber 6, a counter electrode 2, a soaking plate 5, a soaking plate moving mechanism 11, a holding unit 36, a high vacuum exhaust pump 31, a valve 32, a valve 34, and a low vacuum exhaust pump 35. , The discharge electrode 3, the deposition preventing plate 4, the support portion 7, the high-frequency power transmission path 12, the matching unit 13, and the base 37 . In the drawing, an XYZ direction is indicated by an arrow 100. In this figure, the configuration related to gas supply is omitted.

  The film forming chamber 6 forms a film on the substrate inside. The film forming chamber 6 is held on a table 15. The film forming chamber 6 includes a film forming chamber main body 6b and a film forming chamber lid 6a. The film forming chamber main body 6b is a portion on the right side of the line indicated by AA in the drawing. The film forming chamber lid 6a is a left portion. The film forming chamber main body 6b and the film forming chamber lid 6a are united to form a vacuum container when forming a film on the substrate 8 (hereinafter also referred to as “film forming”). The surface indicated by AA is sealed with, for example, an O-ring.

  The counter electrode 2 is a metal plate having holding means (not shown) that can hold the substrate 8. The counter electrode 2 becomes an electrode (example: ground side) facing the discharge electrode 3 during film formation. The counter electrode 2 is held so that one surface is in close contact with the surface of the soaking plate 5. Then, the other surface is brought into close contact with the surface of the substrate 8 during film formation. By being in close contact with the soaking plate 5 and the substrate 8, heat exchange between the soaking plate 5 and the substrate 8 can be easily performed, and the entire substrate 8 can be brought to a uniform temperature.

  The soaking plate 5 has a substantially uniform temperature as a whole, and has a function of making the temperature of the counter electrode 2 in contact with the temperature uniform. Manufactured with a material with good thermal conductivity. When the surface of a plate-like member (example: counter electrode 2) contacts the surface of the soaking plate 5, the soaking plate 5 becomes a heat path, and the temperature distribution of the member can be relaxed.

  The soaking plate moving mechanism 11 includes a drive part 11a and a support part 11b. The drive unit 11a is provided outside the side surface (the right side in FIG. 1) of the film forming chamber body 6b. The support portion 11b is coupled to the drive portion 11a and extends into the film forming chamber 6 through a sealing means (not shown). The soaking plate 5 and the counter electrode 2 are held so as to be substantially parallel to the side surface of the film forming chamber 6 (the right side in FIG. 1).

  By driving the driving unit 11a, the support unit 11b enters and exits the film forming chamber 6 in a direction perpendicular to the side surface (right side in FIG. 1) of the film forming chamber body 6b. At the time of film formation, the support portion 11 b enters the film formation chamber 6 and brings the soaking plate 5, the counter electrode 2 and the substrate 8 close to the discharge electrode 3.

  The holding unit 36 holds the film forming chamber main body 6b on the top of the table 15 with an inclination of θ = 7 ° to 12 ° with respect to the Z direction (vertical direction). More preferably, the tilt is about 10 °. As a result, the surface of the counter electrode 2 in contact with the substrate 8 is directed 7 ° to 12 ° upward with respect to the Z direction. As described above, it is preferable to slightly incline the substrate 8 from the vertical because the substrate 8 can be held with little effort by utilizing the weight of the substrate 8.

  The high vacuum exhaust pump 31 is a high vacuum exhaust vacuum pump that exhausts the gas in the film forming chamber 6. The valve 32 opens and closes the path between the high vacuum exhaust pump 31 and the film forming chamber 6. The low vacuum exhaust pump 35 is a vacuum pump for roughing exhaust that exhausts the gas in the film forming chamber 6. The valve 34 opens and closes the path between the low vacuum exhaust pump 35 and the film forming chamber 6.

  The matching unit 13 (one of the upper side and the lower side is the matching unit 13a and the other is the matching unit 13b) can match the impedance on the output side. High-frequency power is supplied from a high-frequency power supply (not shown) via a high-frequency power transmission line 14 (the one connected to the matching unit 13a is the high-frequency power transmission line 14a and the one connected to the matching unit 13b is the high-frequency power transmission line 14b). Power is transmitted to the discharge electrode 3 through the transmission line 12.

The matching unit 13 is further supplied with a heat medium from, for example, a heat medium supply device (described later) via a heat medium supply pipe 15b (connected to the matching unit 13b), and via a high-frequency power transmission path 12b (described later). To the discharge electrode 3 (feeding point 54 side ). Then, the heat medium is received from the discharge electrode 3 (feed point 53 side) via the high-frequency power transmission path 12a (described later), and is sent to the heat medium supply device via the heat medium supply pipe 15a. In this case, it is preferable to flow the heat medium from the lower matching unit 13b toward the upper matching unit 13a. The heat medium can be spread in the discharge electrode 3 without occurrence of staying places or unreachable places.

  The high-frequency power transmission line 12 (the one connected to the matching unit 13a is the high-frequency power transmission line 12a and the one connected to the matching unit 13b is the high-frequency power transmission line 12b), one to the discharge electrode 3 and the other to the matching unit 13, Each is electrically connected. The high frequency power supplied from the matching unit 13 is supplied to the discharge electrode 3.

  The discharge electrode 3 is divided into a plurality of plates. High-frequency power is received from a feeding point 53 to which the high-frequency feeding transmission path 12a is connected and a feeding point 54 to which the high-frequency feeding transmission path 12b is connected. At the time of film formation, the electrode (example: high-frequency power input side) is opposed to the counter electrode 2 (example: ground side). A film is formed on the substrate 8 by the plasma generated by the discharge between the discharge electrode 3 and the counter electrode 2.

  The support portion 7 extends vertically inward from the side surface (left side in FIG. 1) of the film forming chamber lid 6a. The deposition preventing plate 4 is held so as to be coupled to the deposition preventing plate 4 and cover the space on the discharge electrode 3 opposite to the counter electrode 2. At the same time, it is insulatively coupled to the discharge electrode 3 and holds the discharge electrode 3 so as to be substantially parallel to the side surface (left side in FIG. 1) of the film forming chamber 6.

  The deposition preventing plate 4 is grounded and limits the range in which the film is formed by suppressing the range in which the plasma spreads. In the case of FIG. 1, no film is formed on the wall on the back side (the side opposite to the substrate 8) of the deposition preventing plate 4 inside the film forming chamber 6.

The base 37 holds the film forming chamber 6 (film forming chamber main body 6b) on the upper surface via the holding portion 36. An area including the low vacuum pump 35 is provided inside. The base 37 may not be provided, and in that case, the holding unit 36 is provided on the bottom surface of the room, for example. The low vacuum pump 35 is provided on the side of the film forming chamber 6 that does not hinder the movement of the film forming chamber 6, for example.

  FIG. 2 is a partial perspective view showing a part of the configuration of the first embodiment of the thin film manufacturing apparatus of the present invention. Discharge electrode 3 is divided into a plurality of plates, and includes eight discharge electrodes 3a to 3h in the present embodiment. For each of the discharge electrodes 3a to 3h, a matching unit 13a, a high-frequency power transmission path 14a, a high-frequency power transmission path 12a, a heat medium supply pipe 15a, and a raw material gas pipe 16a are provided on the power feeding point 53 side, respectively. The high-frequency power supply transmission line 14b, the high-frequency power supply transmission line 12b, the heat medium supply pipe 15b, and the source gas pipe 16b are provided on the power supply point 54 side. However, FIG. 2 shows only the matching unit 13, the high-frequency power supply transmission line 14, the high-frequency power supply transmission line 12, the heat medium supply pipe 15, and the raw material gas pipe 16 related to the discharge electrode 3 a.

  Each of the discharge electrodes 3a to 3h is connected to the source gas pipe 16a in the vicinity of the feeding point 53, and is supplied with the source gas from the source gas pipe 16a. Similarly, the source gas pipe 16b is connected in the vicinity of the feeding point 54, and the source gas is supplied from the source gas pipe 16b. Each of the discharge electrodes 3a to 3h discharges the supplied source gas from its surface in the direction indicated by the arrow in the figure.

  3 is a cross-sectional view taken along the line BB of FIG. 2 and a top view of the discharge electrode 3a showing a configuration relating to the discharge electrode 3 in the embodiment of the thin film manufacturing apparatus of the present invention. The discharge electrode 3 includes a source gas circulation pipe 71, a source gas diffusion part 73, a source gas dispersion part 74, and a heat medium circulation pipe 25.

  The source gas flow pipe 71 extends in the longitudinal direction of the discharge electrode 3 and has one end connected to the source gas pipe 16a and the other end connected to the source gas pipe 16b. It has a tubular space in which the source gas flows. The source gas diffusion part 73 is provided between the source gas circulation pipe 71 and the surface of the discharge electrode 3 substantially in parallel with the source gas circulation pipe 71. The source gas flowing through the source gas flow pipe 71 has a space for diffusing toward the surface of the discharge electrode 3. The source gas dispersion part 74 is a plate-like member that extends in the longitudinal direction of the discharge electrode 3 and is provided on the surface of the discharge electrode 3. It has a plurality of holes through which the source gas diffused through the source gas diffusion part 73 passes. The source gas diffuses into the source gas diffusion part 73 while flowing through the source gas circulation pipe 71. The source gas that has reached the source gas dispersion unit 74 is supplied to a space where plasma is generated through a plurality of holes.

  The heat medium flow tube 25 is provided so as to extend in the longitudinal direction of the discharge electrode 3, and one end is connected to the heat medium supply tube 15a and the other end is connected to the heat medium supply tube 15b. It has a tubular space through which the heat medium flows. The heat medium can control the discharge electrode 3 to a predetermined temperature by exchanging heat with the discharge electrode 3. Here, although two heat medium flow pipes 25 are shown, one or three or more heat medium flow pipes may be used.

  FIG. 4 is a schematic block diagram showing a configuration relating to the supply of high-frequency power in the embodiment of the thin film manufacturing apparatus of the present invention. The thin film manufacturing apparatus 1 further includes a power supply unit 60. The power supply unit 60 includes an RF amplifier (high frequency power source A) 62, an RF amplifier (high frequency power source B) 63, a high frequency (RF) oscillator 64, a high frequency (RF) oscillator 65, a changeover switch 66, and a function generator 67.

  The high frequency (RF) oscillator 64 oscillates a high frequency (RF) of 60 MHz, for example, and transmits the high frequency (RF) to the RF amplifier 62 and the changeover switch 66. At that time, any high frequency is phase-modulated by using a phase shifter provided inside. The high frequency (RF) oscillator 65 oscillates a high frequency (RF) of, for example, 58.5 MHz, and transmits it to the changeover switch 66. At that time, the frequency is varied, for example, from 58.5 MHz to 59.9 MHz, or from 60.1 MHz to 61.5 MHz. The changeover switch 66 receives high frequencies from the high frequency oscillators 64 and 65, switches them, and supplies them to the RF amplifier 63. The function generator 67 changes the time ratio of these high frequencies, that is, the duty ratio, when the high frequency is switched from the high frequency oscillators 64 and 65 by the changeover switch 66. The RF amplifier 62 and the RF amplifier 63 function as a high frequency power source by amplifying and outputting the supplied high frequency.

  The high frequency oscillator 64 oscillates a high frequency of 60 MHz, for example, and sends it to the RF amplifier 62 and the changeover switch 66, and the high frequency oscillator 65 oscillates a high frequency of, for example, 58.5 MHz, and sends it to the changeover switch 66. The changeover switch 66 switches the high frequency of 60 MHz sent from the high frequency oscillator 64 and the high frequency of 58.5 MHz sent from the high frequency oscillator 65 at a constant cycle, and sends it to the RF amplifier 63. Therefore, the RF amplifier 62 supplies a high frequency of 60 MHz to the feeding point 53, and the RF amplifier 63 supplies a high frequency of 60 MHz and 58.5 MHz that are switched at a constant cycle to the feeding point 54.

The changeover switch 66 changes the switching between the high frequency of 60 MHz sent from the high frequency oscillator 64 and the high frequency of 58.5 MHz sent from the high frequency oscillator 65 by a signal from the function generator 67 . The function generator 67 changes the high-frequency switching time ratio, that is, the duty ratio, by a signal corresponding to gas conditions such as gas pressure and gas type. The high-frequency oscillator 64 is configured so that the phase of the high-frequency signal sent to one of the RF amplifier 62 and the changeover switch 66 is shifted from the high-frequency signal sent to the other by a phase shifter. The high frequency oscillator 65 is configured such that the oscillation frequency can be varied, for example, from 58.5 MHz to 59.9 MHz, or from 60.1 MHz to 61.5 MHz.

  The details of this operation are as disclosed in JP-A-2002-322563. With this configuration and operation, it is possible to prevent non-uniformity of the plasma generation state caused by standing waves or the like at the discharge electrode 3, and to make the plasma generation state over a large area more uniform.

  FIG. 5 is a diagram showing the relationship among the matching unit, the high-frequency power transmission line, and the discharge electrode in the embodiment of the thin film manufacturing apparatus of the present invention. The high-frequency power transmission line 12 includes an outer conductor 23, an insulator 22, an inner conductor 21, and a heat medium supply pipe 20. Details will be described later.

  The matching unit 13 includes a heat medium supply unit 17 and a matching unit 18. The heat medium supply unit 17 is supplied with a heat medium from the heat medium supply pipe 15. The supplied heat medium is supplied to the discharge electrode 3 (heat medium flow pipe 25) through the heat medium supply pipe 20 of the high-frequency power transmission line 12. Alternatively, a heat medium is received from the discharge electrode 3 (heat medium flow pipe 25) through the heat medium supply pipe 20 of the high-frequency power transmission path 12. The received heat medium is sent to the heat medium supply pipe 15. Since the connection part (heat medium supply part 17) between the heat medium supply pipe 15 and the high-frequency power transmission line 12 is outside the film forming chamber 6, even if the heat medium leaks from the connection part, There is no fouling.

  The matching unit 18 adjusts the characteristic impedance on the output side (discharge electrode 3 side) to a desired value. At the same time, power is supplied via the high-frequency power supply transmission line 14, and power is supplied to the discharge electrode 3 via the high-frequency power supply transmission line 12. The discharge electrode 3 forms plasma between the counter electrode 2 and the counter electrode 2 by the supplied electric power.

FIG. 6 is a diagram showing a cross section of the high-frequency power transmission line in the embodiment of the thin film manufacturing apparatus of the present invention. The high-frequency power transmission line 12 includes an outer conductor 23, an insulator 22, an inner conductor 21, and a heat medium supply pipe 20.
The outer conductor 23 is a hard tubular conductor that is not flexible. For example, it is a cylindrical metal (example: copper). The insulator 22 is provided in a tubular shape inside the outer conductor 23, away from the inner peripheral surface of the outer conductor 23. For example, a cylindrical insulator (eg, alumina) provided inside the cylindrical outer conductor 23. The inner conductor 21 is provided in a tubular shape inside the insulator 22, away from the inner peripheral surface of the insulator 22. For example, it is a cylindrical metal (example: copper) provided inside the cylindrical insulator 22. The heat medium supply pipe 20 is provided inside the internal conductor 21. For example, it is a cylindrical metal (example: stainless steel) provided inside the cylindrical inner conductor 21. The inner conductor 21 itself may be used.

  A high-frequency current due to the high-frequency power flows inside the outer conductor 23 and outside the inner conductor 21. At this time, the gap d1 between the outer conductor 23 and the insulator 22 and the gap d2 between the insulator 22 and the inner conductor 21 are 0.1 mm or more and 1 mm or less so that no discharge occurs due to high frequency power. Is preferred. Further, the material and the wire diameter are determined so as to reduce the resistance loss in accordance with the magnitude of electric power. The linear shape is, for example, 30 mmφ.

  The characteristic impedance of the flexible cable may vary depending on the bending state. However, the high-frequency power transmission line 12 according to the present invention is substantially integral with the outer conductor 23 being a hard tubular conductor, so that it does not bend like a flexible cable and the shape of the cable hardly deforms. Therefore, electrical characteristics such as characteristic impedance can be kept constant. Thus, if the high-frequency power transmission line 12 having appropriate characteristics is used, high-frequency power can be stably fed.

FIG. 7 is a graph showing the relationship between characteristic impedance and various characteristics in the thin film manufacturing apparatus of the present invention.
This figure is a graph showing the relationship between the characteristic impedance of the high-frequency power transmission line 12 and the film thickness distribution of the manufactured thin film. The vertical axis shows the film thickness distribution of the manufactured thin film. A film thickness distribution of 0% indicates a state where there is no film thickness distribution. The horizontal axis represents the characteristic impedance of the high-frequency power transmission line 12. The film thickness distribution is preferably small. In this figure, when the film thickness distribution is 25% or less, the characteristic impedance is preferably 20Ω or more. If it is more than that, the film thickness distribution is almost constant.

The characteristic impedance is determined by the ratio of the diameters of the inner conductor 21 and the outer conductor 23. Here, by fixing the diameter of the outer conductor 23 and the heat medium supply pipe 20, the characteristic impedance is increased, i.e., reducing the diameter of the inner conductor 21, the thickness of the internal conductor 21 is very thin. For this reason, there is a risk that the heat generation of the internal conductor 21 will increase, or the internal conductor 21 will be damaged. Therefore, the upper limit of the characteristic impedance is preferably 300Ω or less.

  From the above, the characteristic impedance is preferably 20Ω to 300Ω. Further, the lower limit is more preferably 22Ω or more, which makes the film thickness distribution 20% or less. Further, the upper limit is more preferably 200Ω or less with less heat generation.

  The electrical length of the high-frequency power transmission line 12 (depending on the electrical length of the portion S in FIG. 5 and the relative permittivity of the material used in the high-frequency power transmission line 12) is a 1/4 · λ wavelength conversion circuit that is an impedance matching theory. However, it is possible to supply power without greatly changing electrical characteristics even at wavelengths other than this wavelength.

  The high frequency power transmission line 12 in the present invention has a stable shape and stable electrical characteristics. Therefore, problems such as abnormal plasma being generated inside the high-frequency power transmission line 12 and cable damage due to heat generated in the high-frequency power transmission line 12 due to power loss are eliminated. Thereby, it is possible to operate stably and continuously to form a film. In addition, it is possible to form a film with a small input power required for film formation, and it is easy to control plasma, and it is possible to improve the film thickness distribution.

  FIG. 8 is a diagram showing a configuration relating to a mechanism for stabilizing the temperature of the discharge electrode in the thin film manufacturing apparatus of the present invention. The mechanism for stabilizing the temperature of the discharge electrode includes the discharge electrode 3, temperature sensors T <b> 1 to T <b> 3, and a heat medium supply device 48.

The discharge electrode 3 includes a heat medium circulation tube 25 that circulates the heat medium therein.
The temperature sensors T <b> 1 to T <b> 3 measure the temperature at a predetermined position in the discharge electrode 3. For example, there are three locations near the feeding point 54 in the discharge electrode 3a, near the center of the discharge electrode 3a, and near the feeding point 53. The same applies to the other discharge electrodes 3 (3b to 3h). However, the temperature sensor may be increased so as to measure more points in each of the discharge electrodes 3a to 3h. In that case, temperature control can be performed with higher accuracy. The temperature sensors T1 to T3 are, for example, thermocouples. The temperature measurement result is used to control the heat medium supply device 48.

The heat medium supply device 48 supplies the temperature-controlled heat medium to the discharge electrode 3 via the heat medium supply pipe 15b, the heat medium supply unit 17 of the matching unit 13b, and the heat medium supply pipe 20 of the high-frequency power transmission line 12b. To the heat medium flow pipe 25 . The heat medium supply pipe 20 from the heating medium flow pipe 25 a high-frequency power feeding path 12a, the temperature of heat medium to be delivered through the heat medium supply unit 17 and the heat medium supply pipe 15a, the matching box 13a to a predetermined temperature The temperature is lowered or lowered and sent to the heat medium supply pipe 15b. The heat medium supply device 48 is provided outside the film forming chamber 6. Thereby, the possibility that the heat medium leaks into the film forming chamber 6 can be reduced, and the degree of freedom of the method of adjusting the temperature can be increased. The heat medium supply device 48 includes a temperature control device 50, a liquid feed pump 46, and a temperature adjustment device 44.

  The temperature adjusting device 44 uses a heating device (not shown) and a cooling device (not shown) included therein to control the heat medium supplied from the heat medium supply pipe 15a to a predetermined value under the control of the temperature control device 50. The temperature is raised or lowered to the temperature and sent to the heat medium supply pipe 15b. The liquid feed pump 46 adjusts the flow rate of the heat medium flowing through the heat medium supply pipe 15b. Based on the temperature difference between the measured temperature of the temperature sensors T1 to T3 and the set value, the temperature control device 50 controls the temperature adjusting device 44 and the liquid feed pump 46 so that the temperature of the temperature sensors T1 to T3 becomes a desired temperature. Control. The control method is, for example, PID control based on the difference between the measured temperature and the set value. The heat medium is exemplified by Garten.

  In this invention, since it has the mechanism which stabilizes the temperature of a discharge electrode, the temperature rise of the discharge electrode 3 can be suppressed and the temperature can be stabilized. Thereby, the temperature rise of the substrate 8 and the in-plane temperature distribution of the substrate 8 can be minimized. Therefore, the warp of the substrate 8 due to the in-plane temperature distribution is eliminated. Further, there is no waiting time required for warping recovery, and productivity can be improved. Moreover, stabilization of the temperature of the discharge electrode 3 is also effective from the viewpoint of film performance. In a solar cell using such a film, battery performance can be improved.

  In the present invention, it is not necessary to separately provide the heat medium pipe (20) for flowing the heat medium in the thin film manufacturing apparatus, and high-frequency power supply and heat medium supply can be realized simultaneously with the same structure. Since the heat medium for the discharge electrode 3 is passed through the coaxial straight pipe of the high-frequency power transmission line 12, the temperature of the high-frequency power transmission line 12 can be stabilized as a result, and more stable high-power power supply is possible. A connection portion for connecting the heat medium supply pipe 15 to the high-frequency power transmission line 12 is on the atmosphere side. Therefore, there is no possibility of leakage of the heat medium (Galden) into the vacuum chamber, and the safety during maintenance is greatly improved.

Next, the thin film manufacturing method of the present invention will be described. Here, the case where a silicon thin film is formed using the above-described thin film manufacturing apparatus will be described.
(1) The substrate 8 is set on the counter electrode 2 of the thin film manufacturing apparatus, and the film forming chamber 6 is set to a predetermined degree of vacuum (example: 10 ⁻⁶ Pa).
(2) Source gas is supplied between the discharge electrode 3 and the substrate 8 through a plurality of holes on the surface of the discharge electrode 3 (source gas dispersion portion 74). The source gas is, for example, SiH ₄ + H ₂ .
(3) A predetermined high frequency power is supplied to the discharge electrode 3 via the high frequency power transmission line 12 connected to the output side while matching the impedance on the output side of the matching unit 13. Thereby, plasma of the source gas is generated between the discharge electrode 3 and the counter electrode 2, and a silicon thin film is formed on the substrate 8.
(4) At the time of film formation, the heat medium is circulated to the heat medium flow pipe 25 provided inside the discharge electrode 3 through the heat medium supply pipe 20 provided inside the high-frequency power transmission path 12. Thereby, the temperature of the discharge electrode 3 is controlled.
At this time,
(4-1) The temperature of the discharge electrode 3 is measured by the temperature sensors T1 to T3.
(4-2) Based on the measurement results of the temperature sensors T1 to T3, at least one of control of the temperature of the heat medium (temperature adjusting device 44) and control of the flow rate of the heat medium (liquid feed pump 46) is executed. Then, the heat medium is supplied to the heat medium supply pipe 15.

  However, it is preferable to perform step (4) continuously while film formation is performed. Step (4) is more preferably performed before steps (2) and (3). In that case, the temperature control of the substrate 8 becomes easier and more accurate.

  In the present invention, since the temperature-controlled discharge electrode 3 is used, the warpage of the substrate 8 is suppressed, and the warping recovery time is unnecessary. Thereby, production efficiency can be improved. In addition, the film performance can be improved by stabilizing the temperature of the discharge electrode 3. Thereby, the battery performance of the solar cell using the film | membrane can be improved.

FIG. 1 is a conceptual diagram showing a configuration of an embodiment of a thin film manufacturing apparatus of the present invention. FIG. 2 is a partial perspective view showing a part of the configuration of the first embodiment of the thin film manufacturing apparatus of the present invention. 3 is a cross-sectional view taken along the line BB of FIG. 2 and a top view of the discharge electrode 3a showing a configuration relating to the discharge electrode 3 in the embodiment of the thin film manufacturing apparatus of the present invention. FIG. 4 is a schematic block diagram showing a configuration relating to the supply of high-frequency power in the embodiment of the thin film manufacturing apparatus of the present invention. FIG. 5 is a diagram showing the relationship among the matching unit, the high-frequency power transmission line, and the discharge electrode in the embodiment of the thin film manufacturing apparatus of the present invention. FIG. 6 is a diagram showing a cross section of the high-frequency power transmission line in the embodiment of the thin film manufacturing apparatus of the present invention. FIG. 7 is a graph showing the relationship between characteristic impedance and various characteristics in the thin film manufacturing apparatus of the present invention. FIG. 8 is a diagram showing a configuration relating to a mechanism for stabilizing the temperature of the discharge electrode in the thin film manufacturing apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thin film manufacturing apparatus 2 Counter electrode 3 (3a-3h) Discharge electrode 4 Deposition plate 5 Heat equalizing plate 6 Film forming chamber 6a Film forming chamber lid 6b Film forming chamber main body 7 Support part 10 Temperature control apparatus 11 Heat equalizing plate movement mechanism 11a drive section 11b support portion 12, 12a, 12b high-frequency power feeding path 13, 13a, 13b matcher 14, 14a, 14b high-frequency power feeding path 15, 15a, 15b heating medium supply pipe 16, 16a, 16b raw material gas pipe 17 Heat medium supply section 18 Matching section 20 Heat medium supply pipe 21 Inner conductor 22 Insulator 23 Outer conductor 25 Heat medium flow pipe 30, 33 pipe 31 High vacuum pump 32, 34 Valve 35 Low vacuum pump 36 Holding section 37 Base 44 Temperature control device 46 Liquid feed pump 48 Heat medium supply device 50 Temperature control device 60 Power source 62 RF amplifier (high frequency power source A)
63 RF amplifier (high frequency power supply B)
64 radio frequency (RF) oscillator 65 radio frequency (RF) oscillator 66 changeover switch 67 function generator 71 raw material gas flow pipe 73 material gas diffusion area 74 feed gas dispersion unit

Claims (5)

A first matching unit capable of matching the impedance on the output side and transmitting the supplied first power;
A first feeding transmission line having one end connected to the first matching unit and mediating transmission of the first power;
A second matching unit capable of matching the impedance on the output side and transmitting the supplied second power;
A second feeding transmission line having one end connected to the second matching unit and mediating transmission of the second power;
A discharge electrode connected to the other end of the first feeding transmission path and the other end of the second feeding transmission path, to which the first power and the second power are supplied;
A counter electrode facing the discharge electrode,
The first power transmission line includes a first heat medium supply pipe for passing a heat medium,
The discharge electrode includes a heat medium flow tube for passing the heat medium,
The second power supply transmission line includes a second heat medium supply pipe for passing the heat medium,
The first matching unit includes a first heat medium supply unit that supplies the heat medium to the first heat medium supply pipe,
The second matching unit is Bei give a second heat medium supplying unit for receiving the heating medium from said second heat medium supply pipe,
Each of the first feeding transmission path and the second feeding transmission path is:
A hard tubular outer conductor;
An insulator provided in a tubular shape inside the outer conductor, apart from the inner peripheral surface of the outer conductor;
An inner conductor provided inside the insulator apart from the inner peripheral surface of the insulator; and
The first heat medium supply pipe and the second heat medium supply pipe, a thin film production apparatus provided inside the respective said inner conductor. A first matching unit capable of matching the impedance on the output side and transmitting the supplied first power;
A first feeding transmission line having one end connected to the first matching unit and mediating transmission of the first power;
A second matching unit capable of matching the impedance on the output side and transmitting the supplied second power;
A second feeding transmission line having one end connected to the second matching unit and mediating transmission of the second power;
A discharge electrode connected to the other end of the first feeding transmission path and the other end of the second feeding transmission path, to which the first power and the second power are supplied;
A counter electrode facing the discharge electrode,
The first power transmission line includes a first heat medium supply pipe for passing a heat medium,
The discharge electrode includes a heat medium flow tube for passing the heat medium,
The second power supply transmission line includes a second heat medium supply pipe for passing the heat medium,
The first matching unit includes a first heat medium supply unit that supplies the heat medium to the first heat medium supply pipe,
The second matching unit includes a second heat medium supply unit that receives the heat medium from the second heat medium supply pipe,
Each of the first feeding transmission path and the second feeding transmission path is:
A hard tubular outer conductor;
An insulator provided in a tubular shape inside the outer conductor, apart from the inner peripheral surface of the outer conductor;
An inner conductor provided inside the insulator apart from the inner peripheral surface of the insulator; and
The inner conductor is a thin film manufacturing apparatus that functions as the first heat medium supply pipe and the second heat medium supply pipe . 3. The thin film according to claim 1, wherein an interval between the outer conductor and the insulator and an interval between the insulator and the inner conductor are both 0.1 mm or more and 1 mm or less. Manufacturing equipment.   (A) supplying a source gas between the discharge electrode and the counter electrode holding the substrate;
  (B1) Matching the impedance on the output side of the first matcher, and supplying the first power to the discharge electrode via the hard tubular outer conductor of the first feed transmission line connected to the output side of the first matcher Supplying a step;
  (B2) Matching the impedance on the output side of the second matcher, and supplying the second power to the discharge electrode via the hard tubular outer conductor of the second feed transmission line connected to the output side of the second matcher Supplying a step;
  (C) A first heat medium supply pipe provided through an insulator provided inside the outer conductor of the first power supply transmission line and separated from an inner peripheral surface of the outer conductor, into the discharge electrode. A heat medium is supplied to the provided heat medium flow pipe, and is provided inside the outer conductor of the second power feeding transmission line and is provided via an insulator separated from the inner peripheral surface of the outer conductor. Receiving a heat medium from the heat medium flow pipe with a heat medium supply pipe.   The step (c) includes:
  (C1) measuring the temperature of the discharge electrode;
  (C2) Controlling at least one of the temperature of the heat medium and the flow rate of the heat medium based on the measurement result, and supplying the temperature to the heat medium flow pipe. Thin film manufacturing method.

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