JP6600492B2 - Sputtering apparatus and sputtering method - Google Patents

Description

  The present invention relates to a sputtering apparatus and a sputtering method.

  Generally, an ITO (Indium Tin Oxide) film is used as the transparent electrode (anode) of the organic EL element.

  When the flatness of the ITO film is low, the protruding portion of the ITO film may pierce a part of the organic EL forming layer in the thickness direction. As a result, the punctured portion becomes a dark spot on the organic EL light emitting surface, and a situation occurs in which the amount of light decreases or disappears in the dark spot. When the flatness of the ITO film is particularly low, the protruding portion of the ITO film may penetrate the entire organic EL forming layer (multilayer). As a result, there arises a situation in which a short circuit between the anode and the cathode of the organic EL element occurs at this penetration portion.

  Further, when the electrical resistivity of the ITO film is high, it is necessary to form the ITO film with a thicker film thickness than when the electrical resistivity of the ITO film is low. As a result, the light transmittance of the ITO film is reduced, and the amount of light on the entire organic EL light emitting surface is reduced.

Japanese Patent No. 3865358 Japanese Patent No. 3797317

  From these viewpoints, a technique for forming an ITO film with high flatness and low resistivity is required. For example, Patent Document 1 discloses a technique for generating an ITO film with low resistivity and good flatness by performing crystallization annealing in the air after forming an amorphous ITO film. Patent Document 2 discloses a technique for producing a transparent conductive film having high flatness and low resistivity by using a special sputtering target material obtained by mixing indium oxide powder and tungsten oxide powder. It is disclosed.

  In the above description, the field of organic EL has been described as an example, but the film formation technique of ITO film with high flatness and low resistivity is the field of semiconductor, the field of flat panel display, the field of solar cell, etc. This technique is also required in various fields other than organic EL.

  Accordingly, an object of the present invention is to provide a sputtering apparatus and a sputtering method for forming an ITO film having high flatness and low resistivity.

A sputtering apparatus according to a first aspect of the present invention is a sputtering apparatus for forming an ITO (Indium Tin Oxide) film on a main surface of a substrate to be transported by sputtering, and a vacuum chamber for forming a processing space therein. A sputtering gas supply unit that supplies a sputtering gas to the processing space, a reactive gas supply unit that supplies a reactive gas to the processing space, and at least one plasma processing unit that performs plasma processing in the processing space And a transport mechanism that transports the base material along a transport path surface including at least one deposition location facing the at least one plasma processing unit, and each of the at least one plasma processing unit includes: Two rotating caps that are cylindrical and whose outer peripheral surfaces are coated with a target material containing indium (In), tin (Sn), and oxygen (O). A pair of cathodes arranged opposite to each other at a certain distance in the processing space, a rotating unit for rotating the two rotating cathodes around their respective central axes, and 1.5 kW / sputter power supply means for supplying a sputter power of m or less, two magnetic field forming portions that are respectively housed in the two rotary cathodes and form a magnetic field in the vicinity of the outer peripheral surface, And at least one inductively coupled antenna for generating inductively coupled plasma in a space including a portion where the magnetic field is formed, and high frequency power supply means for supplying high frequency power to the at least one inductively coupled antenna. Features.
A sputtering apparatus according to a second aspect of the present invention is the sputtering apparatus according to the first aspect of the present invention, wherein the at least one inductively coupled antenna is located between the two rotating cathodes in a plan view. It is characterized by.

A sputtering apparatus according to a third aspect of the present invention is the sputtering apparatus according to the first aspect or the second aspect of the present invention, wherein the sputter power supply means supplies 1.0 kW / The sputtering power of m or less is supplied.

Fourth according sputtering apparatus aspect of the present invention, there is provided a sputtering apparatus according to any one of the first no aspect to the third aspect of the present invention, the sputter power supply means, 0 to the two rotating cathodes It is characterized by supplying a sputtering power of 5 kW / m or more.

A sputtering apparatus according to a fifth aspect of the present invention is the sputtering apparatus according to any one of the first to fourth aspects of the present invention, further comprising a heating unit for heating the substrate to 200 ° C. or higher. It is characterized by providing.

A sputtering apparatus according to a sixth aspect of the present invention is the sputtering apparatus according to any one of the first to fifth aspects of the present invention, wherein the ITO film is used as an anode of an organic EL element. Features.

A sputtering apparatus according to a seventh aspect of the present invention is the sputtering apparatus according to any one of the first to sixth aspects of the present invention, and measures the concentration of the reactive gas in the vacuum chamber. A first measurement unit, a water vapor supply unit for supplying water vapor to the processing space, a second measurement unit for measuring the concentration of the water vapor in the vacuum chamber, and the concentration of the reactive gas during the sputtering film formation in advance. The reactive gas supply unit is feedback-controlled based on the measurement result of the first measurement unit so that the first target value is set, and the concentration of the water vapor during the sputtering film formation is set in advance. And a control unit that feedback-controls the water vapor supply unit based on the measurement result of the second measurement unit so as to obtain two target values.

A sputtering apparatus according to an eighth aspect of the present invention is the sputtering apparatus according to the seventh aspect of the present invention, and is based on the results of film formation performed under different conditions of the concentration of the reactive gas. A first step of setting the concentration of the reactive gas when the resistivity of the deposited ITO film is smaller than a first threshold as the first target value; and the concentration of the reactive gas as the first target. Based on the respective film formation results performed under feedback control with different values of the water vapor concentration, the water vapor concentration when the flatness of the ITO film formed becomes higher than the second threshold value. And a second step of setting the density as the second target value.

The sputtering apparatus according to the ninth aspect of the present invention is the sputtering apparatus according to the eighth aspect of the present invention, wherein the first target value is the resistivity of the ITO film in each film formation result of the first step. Is the concentration of the reactive gas at the time when becomes the smallest.

A sputtering apparatus according to a tenth aspect of the present invention is the sputtering apparatus according to the eighth aspect or the ninth aspect of the present invention, wherein the second target value is determined in each film formation result of the second step. It is the concentration of the water vapor when the flatness of the ITO film is the highest.

A sputtering method according to an eleventh aspect of the present invention uses an apparatus including a vacuum chamber that forms a processing space therein, and at least one plasma processing unit that performs plasma processing in the processing space. A sputtering method in which an ITO (Indium Tin Oxide) film is formed by sputtering on a main surface of a substrate to be transported, wherein each of the at least one plasma processing unit is cylindrical and its outer peripheral surface is indium (In), A cathode pair in which two rotating cathodes coated with a target material containing tin (Sn) and oxygen (O) are arranged to face each other at a predetermined distance in the processing space, and inside the two rotating cathodes and two magnetic field forming unit that forms a magnetic field in the vicinity of its one of the outer peripheral surface are respectively accommodated, the portion where the magnetic field is formed within the processing space At least one inductively coupled antenna that generates inductively coupled plasma in a containing space, wherein the method includes a sputtering gas supplying step of supplying a sputtering gas to the processing space, and a reaction of supplying a reactive gas to the processing space. A reactive gas supply step, a rotation step of rotating each rotary cathode around its central axis, a sputter power supply step of supplying a sputtering power of 1.5 kW / m or less to each rotary cathode, and the at least one induction A high-frequency power supply step of supplying high-frequency power to the coupled antenna, and a transfer step of transferring the base material along a transfer path surface including at least one deposition location facing the at least one plasma processing unit. It is characterized by having.
A sputtering method according to a twelfth aspect of the present invention is the sputtering method according to the eleventh aspect of the present invention, wherein the at least one inductively coupled antenna is located between the two rotating cathodes in plan view. It is characterized by.

A sputtering method according to a thirteenth aspect of the present invention is the sputtering method according to the eleventh aspect or the twelfth aspect of the present invention, wherein the sputtering power supply step is performed at 1.0 kW / m on each rotating cathode. The following sputtering power is supplied.

Sputtering method according to a fourteenth aspect of the present invention, there is provided a eleventh aspect to the sputtering method according to any one of the thirteenth aspect of the of the present invention, the sputter power supply step is 0 to the each rotary cathode. A sputtering power of 5 kW / m or more is supplied.

A sputtering method according to a fifteenth aspect of the present invention is the sputtering method according to any of the eleventh to fourteenth aspects of the present invention, wherein the heating step of heating the substrate to 200 ° C. or higher is performed. It is further provided with the feature.

A sputtering method according to a sixteenth aspect of the present invention is the sputtering method according to any of the eleventh to fifteenth aspects of the present invention, wherein the ITO film is used as an anode of an organic EL element. Features.

A sputtering method according to a seventeenth aspect of the present invention is the sputtering method according to any one of the eleventh to sixteenth aspects of the present invention, wherein the concentration of the reactive gas in the vacuum chamber is measured. A first measurement step, a water vapor supply step for supplying water vapor to the processing space, and a second measurement step for measuring the concentration of the water vapor in the vacuum chamber. In the reactive gas supply step, sputtering is performed. The supply of the reactive gas is feedback-controlled based on the measurement result of the first measurement step so that the concentration of the reactive gas in the film becomes a preset first target value. In the water vapor supply step, , such that the second target value which the concentration of the water vapor in the sputter deposition preset, the steam based on the measurement result of the second measuring step Supply characterized in that it is the feedback control.

A sputtering method according to an eighteenth aspect of the present invention is the sputtering method according to the seventeenth aspect of the present invention, wherein the reactive gas is used as a preparation step for setting the first target value and the second target value. Based on the results of film formation performed under different conditions, the concentration of the reactive gas when the resistivity of the formed ITO film is smaller than the first threshold is used as the first target value. A film was formed on the basis of the first step to be set and the respective film formation results performed under feedback control using the reactive gas concentration as the first target value and under different conditions of the water vapor concentration. And a second step of setting the water vapor concentration when the flatness of the ITO film is higher than a second threshold value as the second target value.

A sputtering method according to a nineteenth aspect of the present invention is the sputtering method according to the eighteenth aspect of the present invention, wherein the first target value is the resistivity of the ITO film in each film formation result of the first step. Is the concentration of the reactive gas at the time when becomes the smallest.

A sputtering method according to a twentieth aspect of the present invention is the sputtering method according to the eighteenth aspect or the nineteenth aspect of the present invention, wherein the second target value is determined in each film formation result of the second step. It is the concentration of the water vapor when the flatness of the ITO film is the highest.

  In the present invention, a rotary type magnetron cathode pair is used. In the rotary type magnetron cathode pair, nodules are less likely to occur during the film forming process than the planar type magnetron cathode. Therefore, in the present invention, various problems due to the generation of nodules (problems such as an increase in the resistivity of the ITO film and generation of particles in the ITO film due to the occurrence of arcing) are unlikely to occur.

  In the present invention, LIA (Low Inductance Antenna: a registered trademark of EM Co., Ltd.) generates inductively coupled plasma in a space including a portion where a magnetic field is formed by a magnetic field forming portion in a processing space. Thereby, the inductively coupled plasma by LIA contributes to the sputtering process by the magnetron cathode pair. For this reason, the film formation rate is improved, and an ITO film having a lower resistivity can be formed, which is desirable.

  In the present invention, the sputtering power supplied to the rotary type magnetron cathode pair is 1.5 kW / m or less. For this reason, the flatness of the ITO film formed in a mode in which the LIA supports the sputtering process is higher than the flatness of the ITO film formed in a mode in which the LIA does not support the sputtering process. As a result, in the present invention, a highly flat ITO film can be formed, which is desirable. Moreover, the resistivity of the ITO film is desirable because it has a low resistivity of 120 μΩcm or less.

It is a cross-sectional schematic diagram which shows the structural example of a sputtering device. It is a cross-sectional schematic diagram which shows the periphery of a plasma processing part. It is a side view which shows an inductive coupling antenna. It is a perspective view which shows the periphery of a plasma processing part. It is a figure which shows the relationship between sputter power and the resistivity of an ITO film. The figure which expands and shows the ITO film | membrane surface in the case where LIA supplies five kinds of sputter power in the aspect which supports a sputter process, and the case where LIA supplies five kinds of sputter power in the aspect which does not support a sputter process. It is. It is a figure which shows the relationship between the deposition thickness of ITO film | membrane and a carrier density, the relationship between the deposition thickness of ITO film | membrane and a hole mobility, and the relationship between the deposition thickness of ITO film | membrane and a resistivity. It is a figure which shows the relationship between the direct current | flow sputtering power supplied to a rotary type magnetron cathode pair, and the flatness of the ITO film | membrane surface. It is a figure which shows the relationship between the heating temperature of the base material by a heating part, and the flatness of the ITO film | membrane surface. It is a cross-sectional schematic diagram which shows the structural example of the sputtering device concerning 2nd Embodiment. It is a figure which shows the relationship between the resistivity of an ITO film | membrane, the flatness of the ITO film | membrane surface, and the density | concentration of each gas in a process space.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, parts having similar configurations and functions are denoted by the same reference numerals, and redundant description is omitted. In addition, the following embodiment is an example which actualized this invention, and is not an example which limits the technical scope of this invention. In the drawings, the size and number of each part may be exaggerated or simplified for easy understanding. Also, in the drawings, XYZ orthogonal coordinate axes may be given to describe directions. The + Z direction on the coordinate axis is a vertically upward direction, and the XY plane is a horizontal plane.

<1 embodiment>
<1.1 Overall Configuration of Sputtering Apparatus 1>
FIG. 1 is a schematic cross-sectional view schematically showing a schematic configuration of the sputtering apparatus 1. FIG. 2 is a schematic cross-sectional view showing the plasma processing unit 50 and its periphery. FIG. 3 is a side view showing an example of the inductively coupled antenna 151 of the plasma processing unit 50. FIG. 4 is a perspective view showing the plasma processing unit 50 and its periphery.

  The sputtering apparatus 1 is an apparatus for sputtering an ITO film on the main surface of the substrate 91 to be conveyed. The base material 91 is configured by, for example, a glass substrate.

  The sputtering apparatus 1 includes a chamber 100 (vacuum chamber), a plasma processing unit 50 disposed therein, a transport mechanism 30 that transports the base material 91, and a control unit 190 that performs overall control of each part of the sputtering apparatus 1. Prepare. The chamber 100 is a hollow member having a rectangular parallelepiped shape. The chamber 100 is disposed so that the upper surface of the bottom plate is in a horizontal posture. Each of the X axis and the Y axis is an axis parallel to the side wall of the chamber 100.

  The sputtering apparatus 1 further includes a chimney 60 that is a cylindrical shielding member disposed so as to surround the periphery of the plasma processing unit 50. The chimney 60 has a function as a shield that limits a plasma range generated in the plasma processing unit 50 and a scattering range of sputtered particles sputtered from the target, and an atmosphere blocking function that blocks the atmosphere inside the chimney from the outside. . The processing space V is a space that is partitioned by the chimney 60 and surrounds the plasma processing unit 50. Therefore, the chamber 100 has a processing space V inside.

  In the chamber 100, a horizontal transfer path surface L is defined above the chimney 60. The extending direction of the conveyance path surface L is the X-axis direction, and the base material 91 is conveyed along the X-axis direction.

  In addition, the sputtering apparatus 1 includes a plate-like heating unit 40 that heats the base material 91 that is transported in the chamber 100. The heating unit 40 is constituted by, for example, a sheath heater disposed on the upper side of the transport path surface L.

  A gate 160 for carrying the base material 91 into the chamber 100 is provided at the end of the transport path plane L on the −X side of the chamber 100. On the other hand, a gate 161 for carrying the base material 91 out of the chamber 100 is provided at the end of the transport path plane L on the + X side of the chamber 100. Moreover, the opening part of other chambers, such as a load lock chamber and an unload lock chamber, is connectable with the X direction both ends of the chamber 100 in the form which maintained airtight. Each of the gates 160 and 161 is configured to be openable and closable.

  In addition, a high vacuum exhaust system 170 is connected to the chamber 100 so that the internal space of the chamber 100 can be decompressed to a vacuum state. The high vacuum exhaust system 170 includes, for example, a vacuum pump (not shown), an exhaust pipe, and an exhaust valve. One end of the exhaust pipe is connected to the vacuum pump, and the other end is connected to the internal space of the chamber 100. Further, the exhaust valve is provided in the middle of the route of the exhaust pipe. Specifically, the exhaust valve is a valve that can automatically adjust the flow rate of the gas flowing through the exhaust pipe. In this configuration, when the exhaust valve is opened while the vacuum pump is operated, the internal space of the chamber 100 is exhausted. The high vacuum exhaust system 170 is controlled by the control unit 190 so as to keep the pressure in the processing space V at a predetermined process pressure.

  In the chamber 100, the transport mechanism 30 includes a plurality of pairs of transport rollers 31 that are opposed to each other across the transport path surface L in the Y direction, and a drive unit (not shown) that rotates and synchronizes these pairs. Consists of including. A plurality of pairs of the conveyance rollers 31 are provided along the X direction which is the extending direction of the conveyance path surface L. In FIG. 1, two rollers positioned on the near side (−Y side) of the two pairs of transport rollers 31 are illustrated.

  The base material 91 is detachably held under the carrier 90 by a claw-like member (not shown) provided on the lower surface of the carrier 90. The carrier 90 is configured by a plate-like tray or the like. In addition to the aspect of this embodiment, various aspects can be adopted as the aspect of holding the base material 91 in the carrier 90. For example, the substrate 91 is held in a state where the lower surface of the substrate 91 can be formed by fitting the substrate 91 into the hollow portion of a plate-like tray having a hollow portion penetrating in the vertical direction. It doesn't matter.

  When the carrier 90 on which the base material 91 is disposed is introduced into the chamber 100 through the gate 160, each transport roller 31 comes into contact with the vicinity of the edge (± Y side edge) of the carrier 90 from below. . Then, the carrier 90 and the base material 91 held by the carrier 90 are transported along the transport path surface L by synchronously rotating the transport rollers 31 by a drive unit (not shown). In the present embodiment, each conveyance roller 31 is rotatable in both clockwise and counterclockwise directions, and the carrier 90 and the substrate 91 held by the carrier 90 are conveyed in both directions (± X directions). explain. The transfer path surface L includes a deposition position P that faces the plasma processing unit 50. For this reason, a film forming process is performed on a portion of the main surface of the base material 91 transported by the transport mechanism 30 that is disposed at the deposition target position P.

  The sputtering apparatus 1 includes a sputtering gas supply unit 510 that supplies a sputtering gas such as an argon gas that is an inert gas to the processing space V, and a reactive gas supply unit 520 that supplies a reactive gas such as an oxygen gas to the processing space V. With. As a result, a mixed atmosphere of a sputtering gas and a reactive gas such as oxygen is formed in the processing space V.

  Specifically, the sputter gas supply unit 510 includes, for example, a sputtering gas supply source 511 that is a supply source of a sputtering gas, and a pipe 512. One end of the pipe 512 is connected to the sputtering gas supply source 511 and the other end is connected to each nozzle 514 communicating with the processing space V. Further, a valve 513 is provided in the course of the pipe 512. The valve 513 adjusts the amount of sputtering gas supplied to the processing space V under the control of the control unit 190. The valve 513 is preferably a valve that can automatically adjust the flow rate of the gas flowing through the pipe, and specifically includes, for example, a mass flow controller.

  Specifically, the reactive gas supply unit 520 includes, for example, a reactive gas supply source 521 that is a reactive gas supply source, and a pipe 522. One end of the pipe 522 is connected to the reactive gas supply source 521, and the other end is branched into a plurality (six in the example of FIG. 4) and a plurality of nozzles 12 (example of FIG. 4) provided in the processing space V. Then, a total of six nozzles 12) are connected, three on the + X side and three on the −X side. A valve 523 is provided in the middle of the route of the pipe 522. The valve 523 adjusts the amount of reactive gas supplied to the processing space V under the control of the control unit 190.

  Each nozzle 12 is provided so as to extend in the Y direction in the + Z side region of the processing space V. Each other end of the pipe 522 is connected to each outer end face of the X direction end faces of each nozzle 12. Each nozzle 12 is formed with a flow path that opens to each end face and is connected to the other end of the pipe 522 and branches into a plurality of portions inside the nozzle. The tip of each flow path reaches and opens each inner end face of both end faces in the X direction of the nozzle 12, and a plurality of discharge ports 11 are formed on each end face.

  An optical fiber probe 13 is provided below each nozzle 12 on the −X side. A spectroscope 14 capable of measuring the spectral intensity of plasma emission incident on the probe 13 is also provided. The spectroscope 14 is electrically connected to the control unit 190, and the measurement value of the spectroscope 14 is supplied to the control unit 190. The control unit 190 controls the valve 523 by the plasma emission monitor (PEM) method based on the output of the spectroscope 14, thereby introducing the reactive gas introduced into the chamber 100 from the reactive gas supply unit 520. To control. The valve 523 is preferably a valve that can automatically adjust the flow rate of the gas flowing through the pipe. For example, the valve 523 preferably includes a mass flow controller.

  Each component included in the sputtering apparatus 1 is electrically connected to a control unit 190 included in the sputtering apparatus 1, and each component is controlled by the control unit 190. Specifically, the control unit 190 includes, for example, a CPU that performs various arithmetic processes, a ROM that stores programs, a RAM that serves as a work area for arithmetic processes, a hard disk that stores programs and various data files, a LAN, and the like. A data communication unit having a data communication function via a general FA computer is connected to each other by a bus line or the like. The control unit 190 is connected to an input unit composed of a display for performing various displays, a keyboard, a mouse, and the like. In the sputtering apparatus 1, the sputtering process is executed under the control of the control unit 190.

<1.2 Plasma processing unit 50>
Hereinafter, the plasma processing unit 50 that performs plasma processing in the processing space V will be described in detail.

  The plasma processing unit 50 is housed in the two rotary cathodes 5 and 6, the two rotary cathodes 19 that rotate the two rotary cathodes 5 and 6 about their respective central axes, and the two rotary cathodes 5 and 6, respectively. Two magnet units 21 and 22 (magnetic field forming unit).

  The rotating cathodes 5 and 6 are arranged to face each other with a certain distance in the X direction in the processing space V, and are configured as a cathode pair. By arranging the rotary cathodes 5 and 6 side by side in this way, the film quality in which radicals are more concentrated on the film formation location P on the substrate 91 can be improved.

  In addition, the plasma processing unit 50 includes a sputtering power source 163 (sputter power supply means) that supplies sputtering power to the two rotating cathodes 5 and 6, a plurality of inductively coupled antennas 151, and high frequency power to each inductively coupled antenna 151. And a high frequency power supply 153 (high frequency power supply means).

The magnet unit 21 (22) forms a magnetic field (static magnetic field) in the vicinity of itself on the outer peripheral surface of the rotating cathode 5 (6). Each inductively coupled antenna 151 is an LIA that generates inductively coupled plasma in a space including a portion of the processing space V where a magnetic field is formed by the magnet units 21 and 22. Note that this inductively coupled plasma is a high-density plasma having an electron spatial density of 3 × 10 ¹⁰ atoms / cm ³ or more.

  The rotary cathode 5 (6) includes a cylindrical base member 8 that extends in the Y direction perpendicular to the transport direction in a horizontal plane, and a cylindrical target 16 that covers the outer periphery of the base member 8. ing. The base member 8 is a conductor, and the material of the target 16 is a material containing indium (In), tin (Sn), and oxygen (O) for forming an ITO film. Note that the rotary cathode 5 (6) may be configured by the cylindrical target 16 without including the base member 8. The target 16 is formed by, for example, a technique of compressing and molding a target material powder into a cylindrical shape, and then inserting and brazing the base member 8.

  In the present specification, when the rotating cathodes 5 and 6 arranged side by side and the magnet units 21 and 22 arranged inside each are integrally expressed, they are referred to as a magnetron cathode pair.

  Both end portions in the direction of the central axis 2 (3) of each base member 8 are respectively closed by lid portions each having a circular opening at the center portion. The length of the rotating cathode 5 (6) in the direction of the central axis 2 (3) is set to 1,400 mm, for example, and the diameter is set to 150 mm, for example.

  The plasma processing unit 50 further includes two pairs of seal bearings 9 and 10 and two cylindrical support rods 7. Each pair of the seal bearings 9 and 10 is provided with the rotary cathode 5 (6) sandwiched in the longitudinal direction (Y direction) of the rotary cathode 5 (6). Each of the seal bearings 9 and 10 includes a base portion standing from the upper surface of the bottom plate of the chamber 100 and a substantially cylindrical cylindrical portion provided on the upper portion of the base portion.

  One end of each support bar 7 is supported by the cylindrical portion of the seal bearing 9, and the other end is supported by the cylindrical portion of the seal bearing 10. Each support bar 7 is inserted into the rotary cathode 5 (6) from the opening of the lid at one end of the base member 8, and passes through the rotary cathode 5 (6) along the central axis 2 (3). 8 is out of the rotating cathode 5 (6) through the opening of the lid at the other end.

  The magnet unit 21 (22) includes a yoke 25 (support plate) formed of a magnetic material such as permeable steel, and a plurality of magnets (a central magnet 23a and a peripheral magnet 23b described later) provided on the yoke 25. It is prepared for.

  The yoke 25 is a flat member and extends in the longitudinal direction (Y direction) of the rotary cathode 5 so as to face the inner peripheral surface of the rotary cathode 5 (6). A central magnet 23 a extending in the longitudinal direction of the yoke 25 is disposed on a center line along the longitudinal direction of the yoke 25 on the surface of the yoke 25 facing the inner peripheral surfaces of the rotary cathodes 5 and 6. On the outer edge portion of the surface of the yoke 25, an annular (endless) peripheral magnet 23b surrounding the periphery of the central magnet 23a is further provided. The central magnet 23a and the peripheral magnet 23b are constituted by permanent magnets, for example.

  The polarities on the target 16 side of the central magnet 23a and the peripheral magnet 23b are different from each other. The polarities of the two magnet units 21 and 22 are configured to be complementary. For example, in the magnet unit 21, the polarity of the central magnet 23a on the target 16 side is N pole and the polarity of the peripheral magnet 23b is S pole, while in the magnet unit 22, the polarity of the central magnet 23a on the target 16 side is S pole. The polarity of the peripheral magnet 23b is the N pole.

  One end of the fixing member 27 is joined to the back surface of the yoke 25. The other end of the fixing member 27 is joined to the support bar 7. Thereby, the magnet units 21 and 22 are connected to the support rod 7. In the present embodiment, the magnet units 21 and 22 constituting the magnetron cathode pair are fixed in a state where the magnet units 21 and 22 are rotated by a predetermined angle in the + Z direction approaching the deposition position P from a position facing each other. For this reason, a relatively strong static magnetic field is formed between the magnet units 21 and 22 in the space between the rotary cathodes 5 and 6 and on the film formation location P side.

  The base part of each seal bearing 9 is provided with a rotating part 19 having a motor and gears (not shown) for transmitting the rotation of the motor. In addition, gears (not shown) that mesh with the gears of the respective rotary portions 19 are provided around the opening of the + Y side lid portion of the base member 8 of the rotary cathodes 5 and 6.

  Each rotating portion 19 rotates the rotating cathode 5 (6) about the central axis 2 (3) by the rotation of the motor. More specifically, the rotating unit 19 has a central axis line so that portions of the outer peripheral surfaces of the rotating cathodes 5 and 6 that face each other move from the inductive coupling antenna 151 side toward the base material 91 side. The rotating cathodes 5 and 6 are rotated in opposite directions around a few times. The rotation speed is set to, for example, 10 to 20 rotations / minute, and the film is rotated at a constant speed in the above rotation speed and rotation direction during the film forming process. The rotary cathodes 5 and 6 are appropriately cooled by circulating cooling water through the seal bearing 10 and the support rod 7.

  The electric wire connected to the power supply 163 for the sputter is branched into two and led into the sealed bearings 10 of the rotary cathodes 5 and 6. At the tip of each electric wire, a brush that contacts the lid portion on the −Y side of the base member 8 of the rotary cathodes 5 and 6 is provided. The power source 163 for sputter supplies sputtering power to the base member 8 through this brush. In this embodiment, the sputtering power source 163 supplies negative potential direct current power to the rotating cathodes 5 and 6. In addition to this, for example, the sputtering power source 163 may supply AC sputtering powers having opposite phases to the rotating cathodes 5 and 6, and the sputtering power source 163 may supply a negative potential to the rotating cathodes 5 and 6. It is also possible to supply a pulsed power consisting of a positive potential.

  When sputtering power is supplied to each base member 8 (and thus each target 16), plasma of sputtering gas is generated on the surface of each target 16 in the processing space V. This plasma is confined with high density in the space between the rotating cathodes 5 and 6 and on the film-forming location P side by the static magnetic field formed by the magnet units 21 and 22. In the present specification, the plasma densified by the magnetic field confinement effect is referred to as magnetron plasma. In the embodiment in which the magnetron cathode pair generates magnetron plasma as in the present embodiment, the plasma is densified compared to the case where one magnetron cathode generates magnetron plasma. For this reason, the aspect of this embodiment is desirable from the viewpoint of improving the film formation rate.

  The plurality of inductively coupled antennas 151 are arranged in a line along the longitudinal direction (Y direction) of the rotary cathodes 5 and 6 at intervals in the portion between the rotary cathodes 5 and 6 in the bottom plate of the chamber 100. Yes. In the example of FIG. 4, the case where the number of inductively coupled antennas 151 is five has been described. However, the number can be appropriately changed according to the length of the rotating cathode 5 (6).

  Each inductively coupled antenna 151 is covered with a dielectric protective member 152 made of quartz glass or the like, and is provided through the bottom plate of the chamber 100. A pair of nozzles 514 for introducing the sputtering gas supplied from the sputtering gas supply source 511 into the processing space V is provided on the ± X side of each inductive coupling antenna 151.

  For example, as shown in FIG. 3, each inductive coupling antenna 151 is formed by bending a metal pipe-like conductor into a U shape, and the bottom plate of the chamber 100 with the “U” shape turned upside down. And projecting into the processing space V. The inductively coupled antenna 151 is appropriately cooled, for example, by circulating cooling water therein.

  One end of each inductively coupled antenna 151 is electrically connected to a high frequency power source 153 via a matching circuit 154. The other end of each inductively coupled antenna 151 is grounded. The high frequency power supply 153 supplies high frequency power to each inductively coupled antenna 151 so that inductively coupled plasma is generated in the processing space V.

  In this configuration, when high frequency power is supplied from the high frequency power source 153 to the inductive coupling antenna 151, a high frequency induction magnetic field is generated around the inductive coupling antenna 151, and the respective inductive couplings of the sputtering gas and the reactive gas are generated in the processing space V. Plasma (Inductively Coupled Plasma: ICP) is generated.

  Each inductively coupled antenna 151 generates inductively coupled plasma in a space including a portion of the processing space V where a magnetic field is formed by the magnet units 21 and 22. As a result, the magnetron plasma generated by the magnetron cathode pair and the inductively coupled plasma generated by the inductively coupled antenna 151 overlap each other to form a mixed plasma. The high-density inductively coupled plasma generated by the inductively coupled antenna 151 also contributes to sputtering of the target 16 together with the magnetron plasma generated by the magnetic units 21 and 22 in the vicinity of the outer peripheral surfaces of the rotating cathodes 5 and 6.

  When the inductively coupled plasma contributes to sputtering in this way, the sputtering voltage can be lowered even when the sputter power supplied to the rotating cathodes 5 and 6 is the same as compared with the case where no inductively coupled plasma contributes ( Impedance can be reduced). Thereby, the film-forming process is performed at a high film-forming rate while the damage given to the film-forming surface of the base material 91 by recoil argon and negative ions flying from the target 16 is reduced.

  As described above, the inductively coupled antenna 151 has a U shape. Such a U-shaped inductively coupled antenna 151 corresponds to an inductively coupled antenna having less than one turn, and has a lower inductance than an inductively coupled antenna having one or more turns. For this reason, the high frequency voltage generated at both ends of the inductive coupling antenna 151 is reduced, and the high frequency fluctuation of the plasma potential accompanying the electrostatic coupling to the generated plasma is suppressed. For this reason, excessive electron loss accompanying the plasma potential fluctuation to the ground potential is reduced, and the plasma potential can be suppressed particularly low. Thereby, damage to the base material 91 can be reduced.

  The sputtering apparatus 1 described above introduces a sputtering gas and a reactive gas into the processing space V of the chamber 100, sputters the ITO target 16 covering the outer periphery of the rotating cathodes 5, 6, and faces the target 16. An ITO film is formed on the substrate 91 to be processed.

<1.3 Film formation process>
In the film forming process, first, the sputtering gas supply unit 510 supplies a sputtering gas such as an argon gas that is an inert gas to the processing space V (a sputtering gas supply process).

  Further, the reactive gas supply unit 520 supplies a reactive gas such as oxygen gas to the processing space V (reactive gas supply step). Thereby, a mixed atmosphere of the sputtering gas and the reactive gas is formed in the processing space V.

  Each rotating unit 19 rotates the rotating cathodes 5 and 6 around the central axes 2 and 3 by the rotation of the motor (rotating process). More specifically, the rotating unit 19 has a central axis line so that portions of the outer peripheral surfaces of the rotating cathodes 5 and 6 that face each other move from the inductive coupling antenna 151 side toward the base material 91 side. The rotating cathodes 5 and 6 are rotated in opposite directions around a few times.

  The power supply 163 for the sputter supplies a sputtering power of 1.5 kW / m or less to the rotating cathodes 5 and 6 (a sputtering power supply process). This sputtering power is, for example, 0.6 kW / m. Here, kW / m is a unit of sputtering power in the rotary cathodes 5 and 6 and means the wattage applied per meter in the axial length of the target 16 wound around the outer periphery of the rotary cathodes 5 and 6. . Magnetron plasma is generated by supplying sputtering power to the rotating cathodes 5 and 6.

  The high frequency power supply 153 supplies high frequency power to each inductive coupling antenna 151 (high frequency power supply step). This high frequency power is, for example, power having a frequency of 13.56 MHz. Thereby, inductively coupled plasma is generated. Then, a mixed plasma of magnetron plasma and inductively coupled plasma is formed between the rotating cathodes 5 and 6 and in the space on the film formation location P side.

  The transport mechanism 30 transports the base material 91 along the transport path surface L (transport process). More specifically, the transport mechanism 30 moves the base material 91 in the ± X direction along the transport path surface L so that the base material 91 passes through the film formation location P a plurality of times.

  Moreover, the base material 91 by which the heating part 40 is conveyed is heated (heating process). The heating unit 40 heats the base material 91 to 300 ° C., for example. If the heating temperature of the base material 91 is 200 ° C. or higher, the ITO film is crystallized with a low resistivity on the base material 91.

  As a result, ITO particles sputtered from the target 16 of the rotary cathodes 5 and 6 are crystallized and deposited on the −Z side main surface of the substrate 91 to be conveyed, and an ITO film is formed. This ITO film is used as an anode of an organic EL element, for example.

<1.4 Resistivity and flatness of ITO film>
FIG. 5 is a diagram showing the relationship between the sputtering power and the resistivity of the generated ITO film. “Planar DC-Bias power”, which is the horizontal axis on the upper side of the figure, indicates the DC sputtering power value applied to the planar magnetron cathode. “Rotary DC-Bias power”, which is the horizontal axis on the lower side of the figure, indicates the DC sputtering power value applied to the rotary magnetron cathode pair. “Bottom Resistivity” on the vertical axis in the figure indicates the minimum resistivity of the ITO film obtained by the film forming process.

  The white squares in the figure are resistivity plots when the magnetron cathode is a planar type and the LIA does not support the sputtering process. The black squares in the figure are resistivity plots when the magnetron cathode is a planar type and the LIA supports the sputtering process. The white circles in the figure are resistivity plots when the magnetron cathode pair is a rotary type and the LIA does not support the sputtering process. The black circles in the figure are resistivity plots when the magnetron cathode pair is a rotary type and the LIA supports the sputtering process. Here, “LIA supports the sputtering process” means that the inductively coupled plasma by LIA contributes to the sputtering process by the magnetron cathode pair as in this embodiment.

Note that, in each processing condition when the graph of FIG. 5 is drawn, the deposition rate of the ITO film when the sputtering power for the planar magnetron cathode is 2.0 W / cm ² , and the rotary magnetron cathode pair The deposition rate of the ITO film when the sputtering power was 1.4 kW / m was substantially the same. For this reason, in FIG. 5, the horizontal axis position of the sputtering power of 2.0 W / cm ^{2 and} the horizontal axis position of the sputtering power of 1.4 kW / m have substantially the same positional relationship.

  As can be seen by comparing the square mark and the circle mark in FIG. 5, when the film formation speed is substantially the same, the ITO film formed by the rotary type magnetron cathode pair is formed by the planar type magnetron cathode. The resistivity is lower than that of the formed ITO film. In the rotary type magnetron cathode pair, the magnetron plasma has a high density and the erosion of the ITO target proceeds more uniformly than the planar type magnetron cathode. Thereby, in the rotary type magnetron cathode pair, the activation of Sn ions is promoted on the film formation surface in the course of the film formation process (compared with the planar type magnetron cathode pair), and the Sn doping efficiency is increased. Nodules are unlikely to occur on the target surface. Increasing the Sn doping efficiency leads to lowering the resistivity of the deposited ITO film. The presence of nodules increases the resistivity of the ITO film to be formed. Therefore, an ITO film having a low resistivity can be stably formed by using a rotary type magnetron cathode pair. Further, since the presence of nodules causes arcing, the use of a rotary magnetron cathode pair suppresses the generation of particles in the ITO film due to arcing.

  In this embodiment, since a rotary magnetron cathode pair including the rotating cathodes 5 and 6 is used, an ITO film having a lower resistivity and a lower particle number can be stably formed.

  Further, as can be seen from the transition of the black circles in FIG. 5, when the sputtering power is in the range of 0.8 to 3.0 kW / m, the resistivity decreases as the sputtering power decreases, and the sputtering power decreases to 0.5 to In the range of 0.8 kW / m, the sputtering power is almost constant. For this reason, regarding the resistivity of the ITO film, the smaller the sputtering power is, the more desirable it is in the range of 0.8 to 3.0 kW / m, and any sputtering power is desirable in the range of 0.5 to 0.8 kW / m.

  Although omitted in FIG. 5, when the sputtering power is less than 0.5, the impurity ratio in the ITO film formed increases due to the decrease in the deposition rate, and the magnetron plasma density decreases. Accordingly, the resistivity of the ITO film increases due to the decrease in the Sn ion activation rate. Therefore, in terms of the deposition rate and resistivity of the ITO film, the sputtering power is desirably 0.5 kW / m or more.

  The low resistivity required for the ITO film varies depending on the product using the ITO film. For example, the resistivity required for the ITO film is preferably 120 μΩcm (micro ohm centimeters) or less. Therefore, as can be seen from FIG. 5, if the sputtering power is 2.1 kW / m or less, the resistivity of the ITO film is desirably a low resistivity of 120 μΩcm or less, which is desirable.

  In this embodiment, LIA is an aspect that supports the sputtering process, and the sputtering power supplied to the rotary magnetron cathode pair is 0.6 kW / m. For this reason, in this embodiment, it is desirable that an ITO film having a sufficiently low resistivity can be formed.

  FIG. 6 is an enlarged view of the ITO film surface when LIA supplies five types of sputtering power in an aspect that supports the sputtering process and when LIA supplies five kinds of sputtering power in an aspect that does not support the sputtering process. It is a figure shown. FIG. 6 shows the resistivity (Res.), The average roughness (Ra), and the maximum roughness (R max), respectively, for a total of 10 cases. The average roughness and the maximum roughness will be described in detail later together with FIG.

  FIG. 7 is a diagram showing the relationship between the deposited thickness of the ITO film and the carrier density, the relationship between the deposited thickness of the ITO film and the hole mobility, and the relationship between the deposited thickness of the ITO film and the resistivity. “Deposition thickness” on the horizontal axis in the figure indicates the deposited thickness of the ITO film. “Carrier density” which is the vertical axis on the right side of the figure indicates the carrier density of the ITO film. “Hall Mobility”, which is the vertical axis on the left side of the figure, indicates the hole mobility of the ITO film. “Resistivity”, which is the vertical axis on the left side of the figure, indicates the resistivity of the ITO film.

  White square marks in the figure are plots of carrier density when LIA does not support the sputtering process. Black square marks in the figure are plots of carrier density when LIA supports the sputtering process. The white circles in the figure are plots of hole mobility when LIA does not support the sputtering process. The black circles in the figure are hole mobility plots when the LIA supports the sputtering process. The white triangles in the figure are resistivity plots when LIA does not support the sputtering process. The black triangles in the figure are resistivity plots when the LIA supports the sputtering process.

  As can be seen by comparing the white square mark and the black square mark in FIG. 7, the carrier density of the ITO film when the LIA supports the sputtering process is more than the carrier density of the ITO film when the LIA does not support the sputtering process. Is also big.

  As can be seen by comparing the white circle mark and the black circle mark in FIG. 7, the hole mobility of the ITO film when the LIA supports the sputtering process is the same as the hole mobility of the ITO film when the LIA does not support the sputtering process. It is almost the same. Strictly speaking, the hole mobility of the ITO film when the LIA supports the sputtering process is slightly smaller than the hole mobility of the ITO film when the LIA does not support the sputtering process.

  Since the product of carrier density and hole mobility is inversely proportional to the resistivity, as can be seen by comparing the white triangle and the black triangle in FIG. 7, the resistivity of the ITO film when LIA supports the sputtering process is LIA. Becomes lower than the resistivity of the ITO film when the sputtering process is not supported. Further, when the black square mark and the white square mark in FIG. 5 are compared, and also when the black circle mark and the white circle mark in FIG. 5 are compared, the resistivity of the ITO film is supported by the LIA supporting the sputtering process. You can see the effect of lowering.

  In this embodiment, since the inductively coupled antenna 151 (LIA) supports the sputtering process, an ITO film having a lower resistivity can be formed, which is desirable.

  FIG. 8 is a diagram showing the relationship between the DC sputtering power supplied to the rotary type magnetron cathode pair and the flatness of the ITO film surface within 5 μm. “DC-Bias power” on the horizontal axis in the figure indicates the DC sputtering power supplied to the rotary magnetron cathode pair. “R max”, which is the vertical axis on the right side of the figure, is the maximum roughness of the ITO film surface. Show. “Ra”, which is the vertical axis on the left side of the drawing, is the average roughness of the ITO film surface, and indicates the average value of the deviation amount from the reference height in the thickness direction of the ITO film surface. The flatness of the ITO film increases as the maximum roughness and average roughness decrease. That is, in this specification, “the flatness of the ITO film is high” means that the maximum roughness and average roughness of the ITO film are small, and “the flatness of the ITO film is low” means that the ITO film has the maximum flatness. Means high roughness and average roughness.

  The white squares in the figure are maximum roughness plots in an embodiment where LIA does not support the sputtering process. Black square marks in the figure are plots of the maximum roughness in an embodiment where LIA supports the sputtering process. White circles in the figure are plots of average roughness in an embodiment where LIA does not support the sputtering process. The black circles in the figure are average roughness plots in an embodiment where LIA supports the sputtering process.

  As can be seen by comparing the white square mark and the black square mark in FIG. 8, when the sputtering power is larger than 1.5 kW / m, the maximum roughness of the ITO film in the aspect in which the LIA supports the sputtering process is as follows. It is larger than the maximum roughness of the ITO film in an embodiment that does not support the sputter process. On the other hand, when the sputtering power is 1.5 kW / m or less, the maximum roughness of the ITO film in the aspect in which the LIA supports the sputtering process is smaller than the maximum roughness of the ITO film in the aspect in which the LIA does not support the sputtering process.

  As can be seen by comparing the white circle mark and the black circle mark in FIG. 8, when the sputtering power is larger than 1.5 kW / m, the average roughness of the ITO film in the aspect in which the LIA supports the sputtering process is the LIA sputtering process. It is larger than the average roughness of the ITO film in an embodiment that does not support the above. On the other hand, when the sputtering power is 1.5 kW / m or less, the average roughness of the ITO film in the aspect in which the LIA supports the sputtering process is smaller than the average roughness of the ITO film in the aspect in which the LIA does not support the sputtering process.

  As described above, when the sputtering power supplied to the rotary type magnetron cathode pair is 1.5 kW / m or less, the flatness of the ITO film formed in such a manner that the LIA supports the sputtering process is the LIA sputtering process. It becomes higher than the flatness of the ITO film formed in a mode not supporting the above. For this reason, it is desirable if the sputtering power is 1.5 kW / m or less.

  The level of flatness required for the ITO film varies depending on the product using the ITO film, but as an example, the average roughness required for the ITO film is preferably 1.5 nm (nanometers) or less. Therefore, as can be seen from FIG. 8, if the sputtering power is 1.3 kW / m or less, it is desirable that the average roughness of the ITO film is high flatness of 1.5 nm or less.

  In this embodiment, LIA is an aspect that supports the sputtering process, and the sputtering power supplied to the rotary magnetron cathode pair is 0.6 kW / m. For this reason, in the present embodiment, an ITO film having sufficiently small maximum roughness and average roughness (that is, sufficiently high flatness) can be formed, which is desirable.

  FIG. 9 is a diagram showing the relationship between the heating temperature of the base material 91 by the heating unit 40 and the flatness of the ITO film surface when the ITO film is formed using a rotary type magnetron cathode pair. “Substrate depo.Temp” on the horizontal axis in the figure indicates the temperature of the substrate 91 on which the ITO film is formed. “R max”, which is the vertical axis on the right side of the figure, is the maximum roughness of the ITO film surface, and represents the difference in height between the highest position (peak) and the lowest position (valley) in the thickness direction of the ITO film surface. Show. “Ra”, which is the vertical axis on the left side of the drawing, is the average roughness of the ITO film surface, and indicates the average value of the deviation amount from the reference height in the thickness direction of the ITO film surface.

  Black square marks in the figure are plots of the maximum roughness in an embodiment where LIA supports the sputtering process. The black circles in the figure are average roughness plots in an embodiment where LIA supports the sputtering process.

  As can be seen from the transition of the black squares in FIG. 9, the maximum roughness decreases as the temperature increases in the heating temperature range of 230 to 300 ° C., and the maximum roughness in the heating temperature range of 300 to 330 ° C. Is almost constant. For this reason, regarding the maximum roughness of the ITO film surface, the higher the temperature is, the more desirable in the range of 230 to 300 ° C., and any temperature in the range of 300 to 330 ° C.

  In the present embodiment, a rotary magnetron cathode pair is used, and LIA supports the sputtering process, and the heating temperature of the base material 91 by the heating unit 40 is 300 ° C. For this reason, in this embodiment, an ITO film having a sufficiently low maximum roughness can be formed, which is desirable.

<2 Second Embodiment>
<2.1 Overall Configuration of Sputtering Apparatus 1A>
FIG. 10 is a schematic cross-sectional view illustrating a configuration example of a sputtering apparatus 1A according to the second embodiment. Hereinafter, the sputtering apparatus 1A according to the second embodiment will be described. However, the same elements as those of the sputtering apparatus 1 according to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

  In addition to the components of the sputtering apparatus 1 of the first embodiment, the sputtering apparatus 1A of the second embodiment includes a water vapor supply unit 530 that supplies water vapor to the processing space V, and the concentration of reactive gas in the processing space V (this embodiment). In the embodiment, it includes a measuring unit 18 capable of measuring the oxygen concentration) and the water vapor concentration (water concentration). Further, the sputtering apparatus 1 </ b> A includes a control unit 190 </ b> A that can communicate with each unit of the sputtering apparatus 1 </ b> A including the water vapor supply unit 530 and the measurement unit 18 instead of the control unit 190 of the sputtering apparatus 1. Hereinafter, differences between the sputtering apparatus 1 and the sputtering apparatus 1A will be mainly described.

  The steam supply unit 530 includes, for example, a steam supply source 531 that is a supply source of steam and a pipe 532. One end of the pipe 532 is connected to the water vapor supply source 531, and the other end is connected to the pipe 522 of the reactive gas supply unit 520. A valve 533 is provided in the middle of the route of the pipe 532. The valve 533 adjusts the amount of water vapor supplied to the processing space V under the control of the control unit 190A. The valve 533 is preferably a valve that can automatically adjust the flow rate of the gas flowing through the pipe, and specifically includes, for example, a mass flow controller.

  The water vapor supplied from the water vapor supply source 531 and the reactive gas supplied from the reactive gas supply source 521 merge in the piping and are discharged from the plurality of nozzles 12 into the processing space V. As described above, the water vapor and the reactive gas are discharged into the processing space V through the common path, so that the distribution of the water vapor and the reactive gas in the processing space V becomes more uniform.

  The measurement unit 18 is composed of a quadrupole mass spectrometer, and can measure the total pressure of gas and the partial pressure of each gas in the processing space V. Therefore, the measurement unit 18 functions as a first measurement unit that measures the concentration of the reactive gas in the processing space V by measuring the total pressure in the processing space V and the partial pressure of the reactive gas, and the processing space. And a function as a second measuring unit that measures the concentration of water vapor in the processing space V by measuring the total pressure in V and the partial pressure of water vapor. Here, the gas concentration is represented by the partial pressure ratio of the gas with respect to the total pressure in the processing space V.

  The control unit 190A performs feedback control of the valve 523 of the reactive gas supply unit 520 based on the measurement result by the measurement unit 18 so that the concentration of the reactive gas during the sputtering film formation becomes the first target value set in advance. To do. Further, the control unit 190A feedback-controls the valve 533 of the water vapor supply unit 530 based on the measurement result by the measurement unit 18 so that the concentration of water vapor during the sputtering film formation becomes a preset second target value.

  During the sputtering film formation period, the measurement unit 18 performs a plurality of measurements at a constant cycle (for example, at intervals of 4 seconds), and the control unit 190A supplies the reactive gas each time a measurement result from the measurement unit 18 is obtained. A control signal is transmitted to the unit 520 and the water vapor supply unit 530. Thereby, the above feedback control is realized.

<2.2 Treatment with Sputtering Apparatus 1A>
FIG. 11 shows each gas measured by the measuring unit 18 in the processing space V when the ITO film is formed using the rotary type magnetron cathode pair, the resistivity of the ITO film, the flatness of the ITO film surface, and the processing space V. It is a figure which shows the relationship with the density | concentration of. “O2 / Total pressure” on the horizontal axis in FIG. 11 indicates the ratio of the pressure of the reactive gas (oxygen) to the total pressure in the processing space V in percentage. “Ra”, which is the vertical axis at the center of the right side of the figure, is the average roughness of the ITO film surface to be formed, and indicates the average value of the deviation amount from the reference height in the thickness direction of the ITO film surface. “R max”, which is the vertical axis on the upper right side of the figure, is the maximum roughness of the ITO film surface to be formed, and is the highest position (peak) and lowest position (valley) in the thickness direction of the ITO film surface. The difference in height is shown. “Resistivity” which is the vertical axis on the left side of the figure indicates the resistivity of the ITO film to be formed.

  In FIG. 11, the substrate 91 is heated to 280 ° C., 1.6 kW RF power is supplied to the LIA, and 0.6 kW / m sputtering power is supplied to the magnetron cathode pair. Each value is shown under conditions where the pressure is 0.5 Pa. The white triangles in the figure are resistivity plots when the water vapor concentration is 0.3%. Black triangles in the figure are resistivity plots when the water vapor concentration is 1.0%. White circles in the figure are plots of average roughness when the water vapor concentration is 0.3%. The black circles in the figure are plots of the average roughness when the water vapor concentration is 1.0%. The white square mark in the figure is a plot of the maximum roughness when the water vapor concentration is 0.3%. Black square marks in the figure are plots of the maximum roughness when the water vapor concentration is 1.0%.

  Below, the process in 1 A of sputtering apparatuses is demonstrated, referring FIG. 10 and FIG.

  In the processing in the sputtering apparatus 1A, first, a preparation step (a first step and a second step described later) for setting the first target value and the second target value is performed.

  In the first step, the water vapor concentration is 0.3% and the reactive gas concentration is different (for example, the oxygen gas concentration is 0.15%, 0.19%, 0 Sputter deposition is performed by the sputtering apparatus 1A (under five concentrations of 23%, 0.25%, and 0.29%). By examining the resistivity and flatness of the ITO film thus obtained, each plot of white triangle marks, each plot of white circle marks, and each plot of white square marks in FIG. 11 is obtained.

  Based on each film formation result, the concentration of the reactive gas when the resistivity of the formed ITO film becomes smaller than the first threshold is set as the first target value. At this time, a threshold (for example, the resistivity is 100 [micro-ohm cm]) required for the final product as the resistivity of the ITO film is used as the first threshold, and the first target value is set. Therefore, the low resistivity of the ITO film is realized through this first step.

  Below, the case where the density | concentration (0.19%) of the reactive gas when the resistivity of an ITO film becomes the minimum in each film-forming result of a 1st process is set as a 1st target value is demonstrated. As described above, in the aspect in which the first target value is set by minimizing the resistivity, the resistivity of the ITO film can be further reduced.

  Next, a 2nd process is performed among preparatory processes. In the second step, under feedback control in which the concentration of the reactive gas is set to the first target value (0.19%) and under different conditions of the water vapor concentration (for example, the water vapor concentration is 0.5%, Sputter deposition is performed by the sputtering apparatus 1A (under conditions of three concentrations of 1.0% and 1.5%).

  Based on each film formation result, when the reactive gas concentration is the first target value (0.19%), the water vapor concentration when the flatness of the ITO film formed becomes higher than the second threshold value. The density is set as the second target value (1.0%). At this time, the threshold value required for the final product as the flatness of the ITO film (for example, the maximum roughness is Rmax = 15 [nm] and the average roughness is Ra = 1.5 [nm]) is used as the second threshold value, A second target value is set. Therefore, through this second step, the ITO film has high flatness. In FIG. 11, among the concentrations of water vapor deposited in the second step (for example, three concentrations of water vapor are 0.5%, 1.0%, and 1.5%), the reactive gas Each plot is drawn when the concentration of water is the first target value (0.19%) and the concentration of water vapor is the second target value (1.0%). In addition, in FIG. 11, in addition to the plots obtained in the first step and the second step as reference plots for explaining the effects described later, the concentration of reactive gas is 0.11% and the concentration of water vapor is Each plot when the second target value is 1.0% and each plot when the reactive gas concentration is 0.27% and the water vapor concentration is the second target value (1.0%) are drawn. It is.

  In the following, the concentration of water vapor (1.0%) when the flatness of the ITO film is the highest (in other words, the maximum roughness Rmax and the average roughness Ra are the smallest) in each film formation result of the second step. Is set as the second target value. Thus, in the aspect which maximizes the flatness and sets the second target value, the ITO film has a higher flatness.

<2.3 Film formation process>
When the preparation process is completed, the film forming process is sequentially performed on the plurality of substrates 91 to be conveyed.

  In the film forming process, first, the sputtering gas supply unit 510 supplies a sputtering gas such as an argon gas that is an inert gas to the processing space V (a sputtering gas supply process). Further, the reactive gas supply unit 520 supplies a reactive gas such as oxygen gas to the processing space V (reactive gas supply step). Furthermore, the water vapor supply unit 530 supplies water vapor to the processing space V (water vapor supply step). As a result, a mixed atmosphere of a sputtering gas, a reactive gas, and water vapor is formed in the processing space V.

  Each rotating unit 19 rotates the rotating cathodes 5 and 6 around the central axes 2 and 3 by the rotation of the motor (rotating process). More specifically, the rotating unit 19 has a central axis line so that portions of the outer peripheral surfaces of the rotating cathodes 5 and 6 that face each other move from the inductive coupling antenna 151 side toward the base material 91 side. The rotating cathodes 5 and 6 are rotated in opposite directions around a few times.

  The power supply 163 for the sputter supplies a sputtering power of 1.5 kW / m or less to the rotating cathodes 5 and 6 (a sputtering power supply process). This sputtering power is, for example, 0.6 kW / m. Magnetron plasma is generated by supplying sputtering power to the rotating cathodes 5 and 6.

  The high frequency power supply 153 supplies high frequency power to each inductive coupling antenna 151 (high frequency power supply step). This high frequency power is, for example, power having a frequency of 13.56 MHz. Thereby, inductively coupled plasma is generated. Then, a mixed plasma of magnetron plasma and inductively coupled plasma is formed between the rotating cathodes 5 and 6 and in the space on the film formation location P side.

  The transport mechanism 30 transports the base material 91 along the transport path surface L (transport process). More specifically, the transport mechanism 30 moves the base material 91 in the ± X direction along the transport path surface L so that the base material 91 passes through the film formation location P a plurality of times.

  Moreover, the base material 91 by which the heating part 40 is conveyed is heated (heating process). The heating unit 40 heats the base material 91 to 280 ° C., for example. If the heating temperature of the base material 91 is 200 ° C. or higher, the ITO film is crystallized with a low resistivity on the base material 91.

  Further, during the film forming process, the measurement unit 18 measures the concentration of the reactive gas in the processing space V a plurality of times at a constant period (first measurement step), and determines the concentration of water vapor in the processing space V. Measure a plurality of times at a constant period (second measurement step). In the reactive gas supply step described above, the reactive gas is supplied based on the measurement result by the measurement unit 18 so that the concentration of the reactive gas during the sputtering film formation becomes the first target value set in advance. Feedback controlled. In the water vapor supply step described above, the supply of water vapor is feedback-controlled based on the measurement result of the measurement unit 18 so that the concentration of water vapor during the sputtering film formation becomes a preset second target value.

<2.4 Resistivity and flatness of ITO film>
Hereinafter, the effects of the sputtering apparatus 1A of the second embodiment will be described from the viewpoint of the resistivity and flatness of the ITO film.

  As already described in the first embodiment, a sputtering power of 1.5 kW / m or less (in this embodiment, 0.6 kW / m) is supplied to a rotary type magnetron cathode pair and sputter formation is performed with LIA support. By performing the film, it is possible to realize a low resistivity and a high flatness of the ITO film.

  Further, as can be seen from FIG. 11, in the second embodiment, the resistivity and the flatness of the ITO film are reduced by adjusting the oxygen concentration and the water vapor concentration. Hereinafter, this point will be described in detail.

  As shown in the six curves in FIG. 11 (two curves related to resistivity, two curves related to average roughness, and two curves related to maximum roughness), under the conditions of this embodiment, the oxygen concentration The first finding is that the curve of the ITO film with the horizontal axis representing the resistivity, the average roughness, and the maximum roughness representing the maximum roughness is a downwardly convex curve having the minimum value. Here, the condition of this embodiment is that a sputtering power of 1.5 kW / m or less (specifically, 0.6 kW / m) is supplied to a rotary type magnetron cathode pair and ITO sputtering is performed with LIA support. It refers to conditions for film formation.

  Also, “Under this condition, when the concentration of water vapor is changed, the minimum value of resistivity corresponds to the minimum value of average roughness, while the corresponding amount of reactive gas has a sufficiently small change amount. The second finding was obtained that the concentration of the reactive gas and the minimum value of the maximum roughness and the corresponding reactive gas concentration vary greatly.

  Furthermore, “Under this condition, even if the concentration of water vapor is changed, the curve shape of the average roughness and the maximum roughness curve are similar, and the minimum value of both corresponds to the corresponding reactive gas. The third finding was obtained that the concentrations were almost the same.

  Based on the above findings, in the preparation step of the second embodiment, first, the concentration of the reactive gas when the resistivity of the deposited ITO film becomes smaller than the first threshold is set as the first target value. The first step is performed, and then the second step of setting the water vapor concentration when the flatness of the deposited ITO film becomes higher than the second threshold as the second target value is performed.

  In the first step, since the concentration of the reactive gas is determined from the viewpoint of reducing the resistivity of the ITO film, the resistivity of the ITO film can be reduced. At this time, if the first target value that minimizes the resistivity of the ITO film is set in accordance with the first knowledge, the resistivity of the ITO film can be further reduced. In the second step, since the concentration of water vapor is determined from the viewpoint of increasing the flatness of the ITO film, higher flatness of the ITO film can be realized from the third knowledge. At this time, if the second target value that minimizes the average roughness and the maximum roughness of the ITO film is set in accordance with the first knowledge, higher flatness of the ITO film can be realized. . Although the water vapor concentration different from that of the first step may be set to the second target value by the second step, the second finding suppresses the lowering of the resistivity of the ITO film.

  In this embodiment, the gas supply amount is feedback-controlled based on the actually measured value (gas partial pressure ratio) obtained in the processing space V by the measuring unit 18. For this reason, in the aspect of this embodiment, for example, compared with other aspects in which the gas supply amount is feedback-controlled based on the actual measurement value obtained by the mass flow controller or the like, the actual amount in the processing space V is actually increased. High-precision feedback control that matches the processing conditions can be performed.

<3 Modification>
While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention.

  In the above-described embodiment, the aspect in which the film forming process is performed on the base material 91 conveyed above one plasma processing unit 50 provided in one chimney 60 has been described. However, the present invention is not limited to this. Absent. The film forming process may be performed on the base material 91 transported above the plurality of plasma processing units 50 provided in the plurality of chimneys 60.

  Moreover, although the said embodiment demonstrated the aspect which performs the film-forming process with respect to the base material 91 conveyed in the horizontal direction, it is not limited to this, For example, with respect to the base material 91 conveyed in the vertical direction A film forming process may be performed, and the conveyance direction of the substrate 91 can be selected as appropriate.

  In addition, each processing condition in the above embodiment (a value of sputtering power supplied to the magnetron cathode pair, a heating temperature of the base material 91, and the like) can be appropriately changed within the scope of the present invention.

  In the second embodiment, the case where the concentration of water vapor in the first step is executed with one value (0.3%) has been described. However, the present invention is not limited to this. The water vapor concentration in the first step may be another value or a plurality of values.

  In the second embodiment, the case where the measurement unit 18 is configured by a quadrupole mass spectrometer has been described, but the present invention is not limited to this. The measuring unit 18 may have another configuration (for example, a configuration using the PEM method) as long as the gas concentration in the processing space can be measured. In the second embodiment, the case where the partial pressure ratio of the gas with respect to the total pressure in the processing space V is used as the gas concentration has been described. However, an approximate value of this value may be used as the gas concentration. For example, when measuring the water vapor concentration by the PEM method, the partial pressure ratio of the hydrogen gas to the argon partial pressure in the processing space V is used as the water vapor gas concentration.

  In the second embodiment, the measurement unit 18 (quadrupole mass spectrometer) can measure the total pressure and the partial pressure of each gas, and functions as a first measurement unit that measures the concentration of reactive gas and water vapor. Although the aspect provided with the function as a 2nd measurement part which measures the density | concentration of this was demonstrated, it is not restricted to this. For example, a mode in which a measurement unit for measuring the total pressure of gas, a measurement unit for measuring the partial pressure of reactive gas, and a measurement unit for measuring the partial pressure of water vapor are provided separately. It doesn't matter.

  In the second embodiment, the measurement unit 18 (quadrupole mass spectrometer) is connected below the processing space V, and the measurement unit 18 can measure the concentration of reactive gas and the concentration of water vapor in the processing space V. However, the present invention is not limited to this. In general, since the ratio of gas can be measured both inside and outside the processing space V within the chamber 100 and is reproducible, the measuring unit 18 can measure the concentration of reactive gas and the concentration of water vapor in the chamber 100. It's enough. Therefore, for example, the measurement unit 18 is connected to the outside of the processing space V (outside the chimney 60) and the inside of the chamber 100, and the measurement unit 18 measures the concentration of reactive gas and the concentration of water vapor in the chamber 100. Possible modes may be used.

  In the second embodiment, the case where the measurement unit 18 is configured by a quadrupole mass spectrometer has been described, but the present invention is not limited to this. The measurement unit 18 may have another configuration (for example, a configuration using the PEM method) as long as the configuration can measure the gas concentration in the processing space or a value reflecting the gas concentration.

  In the second embodiment, the aspect in which the water vapor supplied from the water vapor supply source 531 and the reactive gas supplied from the reactive gas supply source 521 merge in the pipe and are released into the processing space V has been described. It is not limited to this. The aspect may be such that the water vapor supplied from the water vapor supply source 531 and the sputtering gas supplied from the sputtering gas supply source 511 join in the pipe and are discharged into the processing space V. Water vapor, reactive gas, and sputtering gas may be used. May be delivered to the processing space V through different routes.

  As mentioned above, although the sputtering apparatus and sputtering method which concern on embodiment and its modification were demonstrated, these are examples of preferable embodiment for this invention, Comprising: The scope of implementation of this invention is not limited. Within the scope of the invention, the present invention can be freely combined with each embodiment, modified with any component in each embodiment, or increased or decreased with any component in each embodiment.

DESCRIPTION OF SYMBOLS 1,1A Sputtering apparatus 50 Plasma processing part 100 Chamber 151 Inductive coupling antenna 153 High frequency power supply 163 Sputtering power supply 30 Conveyance mechanism 31 Conveyance roller 5,6 Rotating cathode 7 Support rod 8 Base member 16 Target 19 Rotating part 21,22 Magnet unit 60 Chimney 90 Carrier 91 Base material 510 Sputter gas supply unit 520 Reactive gas supply unit 530 Water vapor supply unit 18 Measurement unit V Processing space

Claims (20)

A sputtering apparatus for sputtering an ITO (Indium Tin Oxide) film on the main surface of a substrate to be conveyed,
A vacuum chamber for forming a processing space therein;
A sputtering gas supply unit for supplying a sputtering gas to the processing space;
A reactive gas supply unit for supplying a reactive gas to the processing space;
At least one plasma processing unit for performing plasma processing in the processing space;
A transport mechanism for transporting the base material along a transport path surface including at least one deposition position facing the at least one plasma processing unit;
With
Each of the at least one plasma processing unit includes:
Two rotating cathodes that are cylindrical and whose outer peripheral surfaces are coated with a target material containing indium (In), tin (Sn), and oxygen (O) are arranged to face each other at a predetermined distance in the processing space. A cathode pair;
A rotating section for rotating the two rotating cathodes around respective central axes;
Sputtering power supply means for supplying a sputtering power of 1.5 kW / m or less to each of the two rotating cathodes;
Two magnetic field forming portions that are respectively housed in the two rotary cathodes and form a magnetic field in the vicinity of the outer peripheral surface;
At least one inductively coupled antenna that generates inductively coupled plasma in a space including a portion of the processing space where the magnetic field is formed;
High-frequency power supply means for supplying high-frequency power to the at least one inductively coupled antenna ;
A sputtering apparatus comprising:   The sputtering apparatus according to claim 1,
  The sputtering apparatus, wherein the at least one inductive coupling antenna is located between the two rotating cathodes in a plan view. The sputtering apparatus according to claim 1 or 2 , wherein
The sputtering apparatus, wherein the sputtering power supply means supplies a sputtering power of 1.0 kW / m or less to the two rotating cathodes. The sputtering apparatus according to any one of claims 1 to 3 ,
The sputtering apparatus, wherein the sputtering power supply means supplies a sputtering power of 0.5 kW / m or more to the two rotating cathodes. A sputtering apparatus according to any one of claims 1 to 4 ,
A sputtering apparatus, further comprising a heating unit for heating the substrate to 200 ° C. or higher. A sputtering apparatus according to any one of claims 1 to 5 ,
The sputtering apparatus, wherein the ITO film is used as an anode of an organic EL element. The sputtering apparatus according to any one of claims 1 to 6 ,
A first measurement unit for measuring the concentration of the reactive gas in the vacuum chamber;
A steam supply section for supplying steam to the processing space;
A second measuring unit for measuring the concentration of the water vapor in the vacuum chamber;
The reactive gas supply unit is feedback-controlled based on the measurement result of the first measurement unit so that the concentration of the reactive gas during the sputtering film formation becomes a preset first target value, and the sputter formation is performed. A control unit that feedback-controls the water vapor supply unit based on a measurement result of the second measurement unit so that the concentration of the water vapor in the film becomes a preset second target value;
A sputtering apparatus comprising: The sputtering apparatus according to claim 7 ,
Based on the respective film formation results performed under conditions where the concentration of the reactive gas is different, the concentration of the reactive gas when the resistivity of the deposited ITO film becomes smaller than the first threshold is set to the first concentration. A first step set as one target value;
The flatness of the deposited ITO film is determined based on the results of film formation performed under feedback control using the reactive gas concentration as the first target value and under different conditions of the water vapor concentration. A second step of setting, as the second target value, the concentration of the water vapor when it becomes higher than two threshold values;
Is performed. The sputtering apparatus according to claim 8 ,
The sputtering apparatus according to claim 1, wherein the first target value is a concentration of the reactive gas when the resistivity of the ITO film is minimized in each film formation result of the first step. The sputtering apparatus according to claim 8 or 9 , wherein
The sputtering apparatus according to claim 2, wherein the second target value is a concentration of the water vapor when the flatness of the ITO film becomes the highest in each film formation result of the second step. Using an apparatus including a vacuum chamber that forms a processing space therein and at least one plasma processing unit that executes plasma processing in the processing space, ITO (Indium Tin) Oxide) is a sputtering method for forming a film by sputtering,
Each of the at least one plasma processing unit has a cylindrical shape and two rotating cathodes whose outer peripheral surfaces are covered with a target material containing indium (In), tin (Sn), and oxygen (O). A pair of cathodes arranged opposite to each other at a predetermined distance, two magnetic field forming units that are respectively housed in the two rotating cathodes and form a magnetic field in the vicinity of the outer peripheral surface, and the processing space At least one inductively coupled antenna that generates inductively coupled plasma in a space including a portion where the magnetic field is formed,
With
The method
A sputtering gas supply step of supplying a sputtering gas to the processing space;
A reactive gas supply step of supplying a reactive gas to the processing space;
A rotating step of rotating each rotating cathode around its central axis;
A sputtering power supply step of supplying a sputtering power of 1.5 kW / m or less to each of the rotating cathodes;
A high frequency power supply step of supplying high frequency power to the at least one inductively coupled antenna;
A transporting step of transporting the base material along a transport path surface including at least one film formation location facing the at least one plasma processing unit;
A sputtering method comprising:   It is a sputtering method of Claim 11, Comprising:
  The sputtering method, wherein the at least one inductive coupling antenna is located between the two rotating cathodes in a plan view. The sputtering method according to claim 11 or 12 ,
In the sputtering power supply step, a sputtering power of 1.0 kW / m or less is supplied to each rotating cathode. The sputtering method according to any one of claims 11 to 13 ,
In the sputtering power supply step, a sputtering power of 0.5 kW / m or more is supplied to each rotating cathode. The sputtering method according to any one of claims 11 to 14 ,
A sputtering method, further comprising a heating step of heating the substrate to 200 ° C. or higher. The sputtering method according to any one of claims 11 to 15 ,
The said ITO film | membrane is used as an anode of an organic EL element, The sputtering method characterized by the above-mentioned. The sputtering method according to any one of claims 11 to 16, wherein
A first measurement step of measuring the concentration of the reactive gas in the vacuum chamber;
A steam supply step for supplying steam to the processing space;
A second measuring step for measuring the concentration of the water vapor in the vacuum chamber;
With
In the reactive gas supply step, the reactive gas is supplied based on the measurement result in the first measurement step so that the concentration of the reactive gas during the sputtering film formation becomes a first target value set in advance. Is feedback controlled,
In the water vapor supply step, the water vapor supply is feedback-controlled based on the measurement result in the second measurement step so that the concentration of the water vapor during the sputtering film formation becomes a preset second target value. A sputtering method characterized by the above. The sputtering method according to claim 17 ,
As a preparation step for setting the first target value and the second target value,
Based on the respective film formation results performed under conditions where the concentration of the reactive gas is different, the concentration of the reactive gas when the resistivity of the deposited ITO film becomes smaller than the first threshold is set to the first concentration. A first step set as one target value;
The flatness of the deposited ITO film is determined based on the results of film formation performed under feedback control using the reactive gas concentration as the first target value and under different conditions of the water vapor concentration. A second step of setting, as the second target value, the concentration of the water vapor when it becomes higher than two threshold values;
A sputtering method comprising: The sputtering method according to claim 18 , wherein
The sputtering method according to claim 1, wherein the first target value is a concentration of the reactive gas when the resistivity of the ITO film is minimized in each film formation result of the first step. The sputtering method according to claim 18 or 19 , wherein
The sputtering method, wherein the second target value is the concentration of the water vapor when the flatness of the ITO film becomes the highest in each film formation result of the second step.