TWI696719B - Film forming apparatus and film forming method - Google Patents

Abstract

The invention can suppress the rise of plasma impedance caused by the influence of the dirt of the antenna, and perform stable film formation with less film formation speed and less film quality variation. The film forming device (1) of the present invention includes: a vacuum chamber (10); a cathode (51), which can be provided with a target (512); high-frequency antennas (52), (53), which are arranged near the target; A substrate holding part (31) which holds the substrate (S) against the target; a gas supply part (54) which supplies sputtering gas; a cathode power supply (571) which supplies predetermined cathode power to the cathode; high Frequency power supply (572), which supplies high-frequency power to the high-frequency antenna to generate inductive coupling plasma; and matching devices (575), (576), which are electrically interposed between the high-frequency antenna and the high-frequency power supply Impedance matching; and the high-frequency power supply adjusts the amount of high-frequency power supplied to the high-frequency antenna based on the measurement result of at least one of the current flowing through the cathode and the voltage of the cathode.

Description

Film forming device and film forming method

The present invention relates to a technique for forming a film on a substrate surface using plasma sputtering technology.

The technique of forming a thin film on the surface of a substrate by sputtering a target with plasma includes sputtering the target by inductively coupled plasma. This technique is to arrange a high-frequency antenna near the target integrated with the cathode electrode (hereinafter, simply referred to as "antenna"), and provide high-frequency power to the antenna to generate inductive coupling plasma. In addition, there are also cases where a magnetron cathode system that generates a high-density plasma in a magnetic field formed by a magnetic circuit using a permanent magnet (for example, refer to Patent Documents 1 and 2). This is to increase the film formation speed and film quality in order to generate higher density plasma.

In plasma sputtering technology, the magnitude of the current flowing through the cathode will affect the film formation speed. On the other hand, the magnitude of the cathode voltage affects the film quality, more specifically the film density in the substrate. Therefore, a power supply (cathode power supply) that supplies power to the cathode needs to be configured to be able to accurately manage the cathode current and cathode voltage.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-062568

[Patent Document 2] International Publication No. 2010/023878

When the sputtering is continuously performed, the film-forming material scattered from the target, or the film-forming material can be combined with the components in the environment to form a substance attached to the antenna. As a result, the performance of the antenna gradually decreases. Specifically, the density of the plasma generated by the inductively coupled plasma gradually decreases as the dirt of the antenna becomes serious. In particular, if a conductive substance is attached to the antenna, it acts as a shield against the electric field, so its influence is significant.

The change in plasma density caused by the dirt of the antenna becomes the cause of the change in the load, that is, the impedance of the plasma observed from the cathode power supply, and as a result, the cathode current and the cathode voltage become unstable. For such a situation that the antenna is gradually contaminated due to continuous sputtering, the conventional technology still has a problem that it cannot stably maintain both the film formation speed and the film quality.

The present invention has been completed in view of the above-mentioned problems, and an object of the present invention is to provide a stable film-forming technology capable of suppressing the influence of the dirt of an antenna and performing a film-forming speed and a film quality with little variation.

An aspect of the present invention is a film forming apparatus that forms a film on a substrate by plasma sputtering. To achieve the above object, the apparatus includes: a vacuum chamber; a cathode, which is provided in the vacuum chamber and can be provided A target; a high-frequency antenna, which is arranged near the target in the vacuum chamber; a substrate holding portion, which holds the substrate against the target in the vacuum chamber; and a gas supply portion, which faces the vacuum chamber Indoor supply of sputtering gas; cathode power supply, which supplies predetermined cathode power to the cathode; high-frequency power supply, which supplies high-frequency power to the high-frequency antenna to generate inductively coupled plasma; and a matcher, which is electrically interposed in Between the high-frequency antenna and the high-frequency power supply Impedance matching; and the high-frequency power supply adjusts the magnitude of the high-frequency power supplied to the high-frequency antenna based on the measurement result of at least one of the current flowing through the cathode and the voltage of the cathode to control the cathode power to Specific value.

Furthermore, one aspect of the present invention is a film forming method for forming a film on a substrate by plasma sputtering. To achieve the above object, it includes: arranging a cathode with a target, a high-frequency antenna in a vacuum chamber, and The step of the substrate; the step of supplying the sputtering gas into the vacuum chamber; and supplying predetermined cathode power to the cathode from the power supply section, and supplying the high-frequency power to the high-frequency antenna via a matching device to generate inductively coupled plasma Step; and the power supply unit controls the high-frequency power supplied to the high-frequency antenna based on the measurement result of at least one of the current flowing through the cathode and the voltage of the cathode.

In this specification, the current flowing through the cathode is called "cathode current", and the voltage applied to the cathode is called "cathode voltage". The invention constituted in the above-mentioned manner is to deal with the problem that the adhesion of particles such as film-forming materials generated by sputtering causes serious fouling of the high-frequency antenna, so only the cathode power supply cannot control both the cathode current and the cathode voltage Is an appropriate value. That is, in the present invention, by adjusting the high-frequency power supplied to the high-frequency antenna, these can be controlled to appropriate values at the same time. The details are as follows.

As the sputtering progresses, the high-frequency antenna is contaminated by attachments, and the density of the generated plasma will gradually decrease. This situation causes an increase in the plasma impedance corresponding to the magnitude of the load observed from the power supply side. Regarding the high-frequency power supplied to the high-frequency antenna, the influence of load fluctuations can be suppressed through the matching device. However, the magnitudes of the voltage and current applied to the cathode vary with the load, and as a result, the film formation speed and film quality vary.

In the above invention, measuring at least one of cathode current and cathode voltage Based on this measurement result, the high-frequency power supplied to the high-frequency antenna is controlled. That is, while monitoring cathode power, high-frequency power is controlled based on this result. In the invention constituted in this way, it is possible to detect the change in plasma impedance accompanying the decrease in plasma density caused by the dirt of the high-frequency antenna based on the measurement result of the cathode current or cathode voltage, and to make up for this Increase and decrease of high frequency power. Therefore, even if the high-frequency antenna is contaminated, the resulting change in plasma impedance can be suppressed and the cathode current and cathode voltage can be kept stable.

In this way, the current value and voltage value of the cathode power provided to the cathode can be maintained at appropriate values. As a result, the film formation can be continuously performed while maintaining a fixed film formation speed and film quality.

As described above, according to the present invention, by increasing or decreasing the power supplied to the high-frequency antenna, it is possible to suppress the change in the plasma density caused by the attachment to the high-frequency antenna. As a result, both the current and the voltage supplied to the cathode can be maintained at appropriate values, the film formation speed and film quality can be stabilized, and the film formation can be continued.

1. 1a‧‧‧film forming device

10‧‧‧Vacuum chamber

11‧‧‧ Gate

12‧‧‧Vacuum pump

13‧‧‧pressure sensor

30‧‧‧Transport organization

31‧‧‧Transport roller (substrate holding section)

32‧‧‧Transport drive

50‧‧‧Sputter source

51‧‧‧Sputtering cathode (cathode)

52, 53‧‧‧ Inductively coupled antenna (high frequency antenna)

54‧‧‧Gas Supply Department

55‧‧‧Chimney

56‧‧‧Gas Supply Department

57‧‧‧Power Department

58‧‧‧cooling mechanism

59‧‧‧Optical Probe

70‧‧‧Sputter source

71, 72‧‧‧ Rotating cathode

73、74‧‧‧Magnet unit

75、76‧‧‧rotary drive

77‧‧‧Inductively coupled antenna

90‧‧‧Control unit

91‧‧‧Central Processing Unit (CPU)

92‧‧‧Opening and closing control department

93‧‧‧ Gas Environment Control Department

94‧‧‧Transport Control Department

95‧‧‧Film-forming process control department

96‧‧‧Memory and storage

97‧‧‧Interface

511‧‧‧support plate

512‧‧‧ target

513‧‧‧Anode mask

514‧‧‧Housing

515‧‧‧Magnet unit

515a‧‧‧Yoke

515b‧‧‧Central magnet

515c‧‧‧Peripheral magnet

521, 531‧‧‧ conductor (linear conductor)

522, 532‧‧‧ Dielectric (dielectric layer)

571‧‧‧ Cathode power supply

572‧‧‧High frequency power supply

573‧‧‧Current Measurement Department

574‧‧‧Voltage Measurement Department

575、576‧‧‧matcher

611, 623, 624, 633, 634, 635

612, 613, 621, 622, 631, 632

711, 721‧‧‧ base member

712, 722‧‧‧ target material

731, 741‧‧‧Yoke

732,742‧‧‧Central magnet

733、743‧‧‧Peripheral magnet

734、744‧‧‧Fixed member

735、745‧‧‧Supporting member

771‧‧‧Conductor

772‧‧‧Dielectric

Ia‧‧‧current value

It‧‧‧ current target value

Pa, Pb, Vb‧‧‧ value

Po‧‧‧start value

△I、△V‧‧‧Target range

PL‧‧‧Plasma space

S‧‧‧Substrate

SP‧‧‧Internal space

S101~S108‧‧‧Step

S201~S206‧‧‧Step

T‧‧‧Tray

Vt‧‧‧Voltage target value

Wk‧‧‧Workpiece

X, Y, Z ‧‧‧ coordinate axis

FIG. 1 is a side view and a plan view showing a schematic configuration of an embodiment of a film forming apparatus of the present invention.

FIG. 2 is a perspective view showing the arrangement of main components inside the film forming apparatus.

FIG. 3 is a block diagram showing the electrical configuration of the film forming apparatus.

FIG. 4 is a diagram showing the operation of the sputtering source.

FIG. 5 is a flowchart showing the film forming process of the film forming apparatus.

6 is a diagram showing the relationship between the control method of the cathode power supply and the control input that can be used for the high-frequency power supply.

7 is a flowchart showing an example of output control processing in a high-frequency power supply.

FIG. 8 is a diagram illustrating the effect of the output control process.

9 is a diagram illustrating a case where the cathode current is set to constant current control and the cathode voltage is set to control input.

10A is a diagram showing a first modification of the sputtering source.

10B is a diagram showing a second modification of the sputtering source.

10C is a diagram showing a third modification of the sputtering source.

FIG. 11 is a diagram showing a configuration example of a rotary cathode type film forming apparatus.

FIG. 1 is a side view and a plan view showing a schematic configuration of an embodiment of a film forming apparatus of the present invention. FIG. 2 is a perspective view showing the arrangement of main components inside the film forming apparatus. FIG. 3 is a block diagram showing the electrical configuration of the film forming apparatus. In order to uniformly express the directions in the following description, the XYZ rectangular coordinate axis is set as shown in FIG. 1. The XY plane represents the horizontal plane. In addition, the Z axis represents the vertical axis, and in more detail, the (-Z) direction represents the vertical downward direction.

The film forming apparatus 1 is a device for forming a film on the surface of the substrate S to be processed by plasma sputtering. For example, the film forming apparatus 1 can be applied to form a metal film such as titanium, chromium, nickel, or a metal oxide film such as aluminum oxide on one surface of a glass substrate as a substrate S, a flat plate, a sheet, or a thin film made of resin. However, the materials of the substrate and the film are not limited thereto, and may be arbitrary. In addition, here, the case where the rectangular or monolithic substrate S is formed as an example will be described, but the substrate S may have any shape.

The substrate S retains its peripheral edge portion by the frame-shaped tray T having an opening in the central portion, and most of the lower surface including the central portion is downwardly opened, resulting in Transported in the membrane device 1. In this way, even the thinner or larger format and easily deflectable substrate S can be stably transported while maintaining the horizontal posture. In the following description, a structure in which the tray T supports the substrate S and integrates the tray T and the substrate S is referred to as a workpiece Wk that is the processing target of the film forming apparatus 1.

In addition, the conveyance state of the substrate S is not limited to this, and may be arbitrary. For example, the substrate S may be transported in a single body. For example, the substrate S may be transported in a state where the upper surface is sucked and held on the opposite side to the lower surface as the film-forming surface. . In addition, for example, the tray T may be configured as a part that constitutes a part of the film forming apparatus 1, or may be configured separately from the film forming apparatus 1 and carried in from the outside together with the substrate S. In addition, the substrate is not limited to a person in a horizontal posture, for example, it may be transported in a state where the main surface is slightly vertical. In this case, the transport direction of the substrate may be either horizontal or vertical.

The film forming apparatus 1 includes a vacuum chamber 10, a transport mechanism 30 that transports a workpiece Wk, a sputtering source 50, and a control unit 90 that collectively controls the entire film forming apparatus 1. The vacuum chamber 10 is a hollow box-shaped member having a substantially rectangular parallelepiped shape, and is arranged such that the upper surface of the bottom plate is in a horizontal posture. The vacuum chamber 10 is made of a material mainly made of metals such as stainless steel and aluminum. However, in order to be able to view the inside of the chamber, for example, a transparent window made of quartz glass may be partially provided.

As shown in FIG. 3, the vacuum chamber 10 is provided with a gate 11 that opens and closes the internal space SP of the vacuum chamber 10 and the external space or the processing space in other processing chambers. Furthermore, a vacuum pump 12 for reducing the pressure in the vacuum chamber 10 and a pressure sensor 13 for measuring the air pressure of the internal space SP of the vacuum chamber 10 are provided. Although the description is omitted in FIG. 1, the shutter 11 is provided at one or both of the (-X) side end and the (+X) side end of the vacuum chamber 10.

The gate 11 is opened and closed by a gate opening and closing control unit 92 provided in the control unit 90. When the gate 11 is open, the workpiece Wk can be carried in and out. On the other hand, when the gate 11 is closed, the vacuum chamber 10 is in an airtight state. The vacuum pump 12 and the pressure sensor 13 are connected to the gas environment control unit 93 provided in the control unit 90. The gas environment control unit 93 controls the vacuum pump 12 based on the pressure measurement result in the vacuum chamber 10 obtained by the pressure sensor 13, and controls the internal space SP of the vacuum chamber 10 to a predetermined air pressure. The gas environment control unit 93 sets the film pressure, that is, the film pressure in the vacuum chamber 10 during the film forming operation described below in accordance with a control command from a central processing unit (CPU) 91.

The transport mechanism 30 has a function of transporting the workpiece Wk along a slightly horizontal transport path. Specifically, the transport mechanism 30 includes: a plurality of transport rollers 31 that support the workpiece Wk in the processing chamber 10 by abutting on the lower surface of the tray T holding the substrate S; and by rotating the transport roller 31 The conveying drive unit 32 that moves the workpiece Wk in the X direction. The transport drive unit 32 is controlled by the transport control unit 94 provided in the control unit 90. The transfer mechanism 30 configured in this manner transfers the substrate S while maintaining the horizontal posture in the vacuum chamber 10, and moves the substrate S in the X direction. The movement of the substrate S by the transport mechanism 30 may be a reciprocating movement as indicated by a dotted arrow in FIG. 1, or it may be either the (+X) direction or the (-X) direction mobile.

A sputtering source 50 is provided below the substrate S transferred in the vacuum chamber 10 by the transfer mechanism 30. The sputtering source 50 includes: a sputtering cathode 51; a pair of inductively coupled antennas 52 and 53 provided so as to sandwich the sputtering cathode 51 from the X direction; and a sputtering gas supply that supplies sputtering gas around the sputtering cathode 51 Nozzles 54, 54. Furthermore, a box-shaped chimney 55 formed of a metal plate is provided so as to cover the surroundings of the sputtering cathode 51, the inductive coupling antennas 52, 53 and the sputtering gas supply nozzles 54, 54.

The sputtering cathode 51 includes a support plate 511 formed into a plate shape using a conductive material such as a copper plate. On the upper surface of the support plate 511, a target 512 formed in a flat plate shape (planar shape) using the film forming material of the substrate S is mounted. The target 512 is surrounded by an anode shield 513. The anode mask 513 has a frame shape with an opening on the upper surface equal to the plane size of the target 512, covering the periphery of the target 512. Via the opening, the upper surface of the target 512 faces the lower surface of the substrate S. In addition, in the plan view of FIG. 1 and FIG. 2, in order to clearly show the internal structure of the sputtering source 50, the chimney 55 only shows its outer shape with a two-dot chain line.

The lower part of the support plate 511 is covered by a case 514 formed in a box shape. The housing 514 is fixed to the bottom surface of the vacuum chamber 10. A magnet unit 515 is provided in the space between the lower surface of the support plate 511 and the housing 514. A fluid such as cooling water is supplied as a refrigerant from the cooling mechanism 58 described below to the gaps around it.

The magnet unit 515 disposed under the support plate 511 includes: a yoke 515a; a plurality of magnets provided on the yoke 515a, that is, a central magnet 515b; and a peripheral magnet 515c provided to surround the central magnet 515b. The yoke 515a is a flat plate member formed of a magnetic material such as permeable steel and extending in the Y direction. The yoke 515a is fixed to the housing 514 by a fixing member not shown.

A central magnet 515b extending in the Y direction is disposed on the upper surface of the yoke 515a along the center line in the longitudinal direction (Y direction). In addition, a ring-shaped (ring-shaped) peripheral magnet 515c surrounding the center magnet 515b is provided on the outer edge of the upper surface of the yoke 515a. The central magnet 515b and the peripheral magnet 515c are, for example, permanent magnets. The polarities of the central magnet 515b and the peripheral magnet 515c on the side opposite to the lower surface of the support plate 511 are different from each other. Therefore, the magnet unit 515 forms a static magnetic field around the target 512. The supporting cathode plate 511 to which the target 512 is mounted, the magnet unit 515, the housing 514, and the like constitute the magnetron cathode as a whole.

A pair of inductively coupled antennas 52 and 53 protrudes from the bottom surface of the vacuum chamber 10 via the sputtering cathode 51 in the vacuum chamber 10. The inductively coupled antennas 52 and 53 are also called LIA (Low Inductance Antenna). As shown in FIG. 2, the surfaces of the conductors 521 and 531 formed in a slightly U shape have a structure covered with dielectrics 522 and 532 such as quartz. The conductors 521 and 531 penetrate the bottom surface of the vacuum chamber 10 in a state where the U shape is turned upside down and extend in the Y direction. The conductors 521 and 531 have different positions in the Y direction and are arranged and arranged in several numbers. The dielectric substance 522 can also be separately provided by individually covering the plurality of conductors 521, and can also be provided by covering the plurality of conductors 521 together. The same is true for the dielectric 532.

The surfaces of the conductors 521 and 531 are covered with dielectrics 522 and 532, thereby preventing the conductors 521 and 531 from being exposed to plasma. This prevents the constituent elements of the conductors 521 and 531 from being mixed into the film on the substrate S. In addition, as described below, the inductively coupled plasma is generated by the high-frequency current applied to the conductors 521 and 531, which can suppress abnormal discharge such as arc discharge and generate stable plasma.

The conductors 521 and 531 of the inductively coupled antennas 52 and 53 can be regarded as loop antennas with the X direction as the winding axis direction and the number of windings is less than one. Therefore, it is low inductance. By arranging several such small antennas in a direction orthogonal to the winding axis direction, while suppressing the increase in inductance, the induced magnetic field for generating plasma described below can be formed in a wide range. In addition, a pair of antenna rows including a plurality of antennas respectively arranged in the Y direction are separated and arranged in parallel in the X direction, whereby a strong and uniform induced magnetic field can be generated in the space between the two antenna rows.

In the surrounding space of the sputtering cathode 51 interposed between the inductive coupling antennas 52 and 53, a sputtering gas (for example, an inert gas) is introduced from the gas supply part 56. Specifically, a pair of nozzles 54 and 54 are provided in the true direction with the sputtering cathode 51 in the X direction. The bottom surface of the cavity 10. The nozzles 54 and 54 are respectively connected to the gas supply part 56. The gas supply unit 56 supplies an inert gas, such as argon gas or xenon gas, as a sputtering gas to the nozzles 54 and 54 according to a control command from the film formation process control unit 95. The sputtering gas is sprayed from the nozzles 54 and 54 to the surroundings of the sputtering cathode 51. The gas supply unit 56 preferably has a flow rate adjustment function that automatically controls the flow rate of the sputtering gas, and may be provided with a mass flow controller, for example.

At a position in the chimney 55 facing the surface of the target 512, an optical probe 59 including, for example, an optical fiber is disposed. A part of the plasma light generated in the space in the chimney 55 is incident on the optical probe 59. The optical probe 59 is connected to a beam splitter (not shown), and the output signal of the beam splitter is input to the control unit 90.

The control unit 90 measures the luminous intensity of the plasma in the plasma space by the proton electrolyte membrane method (PEM) based on the output signal of the spectroscope. Specifically, for the film-forming particles flying out of the target 512 by sputtering, atoms or molecules excited in the plasma, or ions (eg, argon atoms), the light intensity of the inherent spectral components of the substance is measured by Therefore, the concentration of the substance in the plasma space is detected. From this, the plasma density in the plasma space can be obtained.

FIG. 4 is a diagram showing the operation of the sputtering source. An appropriate voltage is applied from the power supply 57 between the sputtering cathode 51 and the inductively coupled antennas 52 and 53. Specifically, the support plate 511 of the sputtering cathode 51 is connected to the cathode power supply 571 provided in the power supply section 57. Furthermore, a negative potential that is appropriate to the ground potential is supplied from the cathode power supply 571 to the support plate 511. As the voltage output by the cathode power supply 571, direct current, direct current pulse, sine wave alternating current, rectangular wave alternating current, rectangular wave alternating current pulse, and a plurality of these can be used. However, in the following description, when referring to "cathode voltage", it refers to the voltage among the negative DC or negative AC components of various waveforms output from the cathode power supply 571. another On the other hand, the high-frequency power supply 572 provided in the power supply section 57 is connected to the inductive coupling antennas 52 and 53 via matching devices 575 and 576, respectively, and appropriate high-frequency power is applied from the high-frequency power supply 572.

The matching devices 575 and 576 are provided to maximize the efficiency of power transmission from the high-frequency power supply 572 to the load by matching the impedance of the load with respect to the high-frequency power supply 572 to the power supply impedance. Since the principle and structure of the matching device for this purpose are well known, detailed description is omitted, but for example, a form in which the capacity of the built-in capacitor is changed according to the change in the impedance of the load can be used.

The voltage waveforms respectively output from the cathode power supply 571 and the high-frequency power supply 572 are set by control commands from the film forming process control section 95 of the control unit 90. In addition, a current measuring section 573 is interposed between the wiring from the cathode power supply 571 to the support plate 511. The current measuring unit 573 measures the cathode current which is the current flowing through the wiring. The detection output of the current measurement unit 573 is input to the cathode power supply 571 and the high-frequency power supply 572. In addition, a voltage measuring section 574 is provided between the wiring and the device ground, and measures the cathode voltage, more specifically the DC voltage of the support plate 511 with respect to the ground potential. The detection output of the voltage measuring section 574 is also input to the cathode power supply 571 and the high-frequency power supply 572.

The cathode power supply 571 controls the output power based on the value of the cathode current measured by the current measurement unit 573 and the value of the cathode voltage measured by the voltage measurement unit 574. As a control method, a constant current control that maintains the value of the cathode current to be fixed, a constant voltage control that maintains the value of the cathode voltage to be fixed, and a constant power control that maintains the product of the cathode current and the cathode voltage to be fixed.

On the other hand, to the high-frequency power supply 572, in addition to the outputs from the current measuring section 573 and the voltage measuring section 574, the detection output from the optical probe 59 that measures the luminous intensity of the plasma is also input. In addition, in FIG. 4, to explain the principle, it is described that the optical probe 59 is directly connected to the high-frequency power supply 572. However, in fact, based on self-optical probes 59 The signal provided by the splitter provides a value corresponding to the plasma density detected by the control unit 90 from the control unit 90 to the high-frequency power supply 572. The output control of the high-frequency power supply 572 will be described below.

High-frequency power is supplied from the high-frequency power source 572 to the inductively coupled antennas 52 and 53 through matching devices 575 and 576 (for example, high-frequency power at a frequency of 13.56 MHz), thereby generating high-frequency induction in the space around the inductively coupled antennas 52 and 53 The magnetic field generates a plasma of sputtering gas. More specifically, a hybrid plasma of magnetron plasma and inductively coupled plasma (Inductivity Coupled Plasma; ICP) is generated. The sputtering cathode 51 including the target 512 and the magnet unit 515 and the inductive coupling antennas 52 and 53 both extend along the Y direction perpendicular to the paper surface of FIG. 1. Therefore, the plasma space PL in which the plasma is generated also becomes a space area having a shape extending long in the Y direction along the surface of the sputtering cathode 51.

The cations contained in the plasma generated in the plasma space PL in this way (indicated by open circles in FIG. 4) collide with the sputtering cathode 51 provided with a negative potential. As a result, the surface of the target 512 is sputtered, and fine particles of the target material flying out of the target 512 are attached to the lower surface of the substrate S as film-forming particles (indicated by solid circles in FIG. 4 ). As a result, a film is formed on the surface (lower surface) of the substrate S. Specifically, film formation by plasma sputtering is performed on the strip-shaped region in the Y direction on the lower surface of the substrate S. By scanning and moving the substrate S in the X direction parallel to the main surface of the substrate S and orthogonal to the Y direction, film formation is performed two-dimensionally over the entire film formation target area.

The chimney 55 is provided so as to cover the plasma space PL. As a result, the plasma particles generated in the plasma space PL and the film-forming particles generated by the sputtering are prevented from scattering in the vacuum chamber 10. As a result, the flying direction of the film-forming particles flying out from the surface of the target 512 by sputtering is limited to the direction toward the substrate S. Therefore, the target material can efficiently contribute to film formation. The self-cooling mechanism 58 supplies cooling water to the sputtering cathode 51 to suppress The temperature of the target 512 exposed to the plasma rises.

As shown in FIG. 3, in addition to the above, the control unit 90 includes a CPU (Central Processing Unit) 91 that performs various arithmetic processing, a memory and storage 96 that stores programs or various data executed by the CPU 91, and is responsible for interacting with external devices and Interface 97 for the exchange of information between users. For example, a general-purpose computer device can be used as the control unit 90. In addition, the functional blocks such as the gate opening and closing control section 92, the gas environment control section 93, the transport control section 94, and the film formation process control section 95 provided in the control unit 90 can also be realized by dedicated hardware By. Alternatively, it may be implemented on software executed by the CPU 91.

FIG. 5 is a flowchart showing the film forming process of the film forming apparatus. This processing is realized by the control unit 90 causing each part of the film forming apparatus 1 to perform a predetermined operation based on a control program prepared in advance. Before the workpiece Wk including the substrate S as the film formation target is carried into the film formation apparatus 1, the exhaust of the vacuum chamber 10 is started (step S101 ).

In a state where the predetermined pressure is controlled in the vacuum chamber 10, the plasma lighting is started (step S102). Specifically, the sputtering gas is ejected from the nozzle 54 into the vacuum chamber 10 at a predetermined flow rate. Then, the power supply 57 applies a predetermined voltage to the sputtering cathode 51 and the inductively coupled antennas 52 and 53 respectively, thereby generating a mixed plasma of the magnetron plasma and the inductively coupled plasma in the vacuum chamber 10.

With the plasma lighted in the vacuum chamber 10 in advance in this way, the shutter 11 is opened, and the workpiece Wk is received in the vacuum chamber 10 (step S103). In order to stabilize the lighting state of the plasma, it is desirable that the workpiece Wk is carried in from another vacuum chamber (not shown) that maintains the same vacuum state as the vacuum chamber 10. The same is true when the workpiece after film formation is carried out. Furthermore, the gate for receiving the workpiece Wk before the film forming process The gate for sending out the workpiece Wk after the film forming process may be different from each other.

When the work Wk is carried into the vacuum chamber 10, the transport mechanism 30 scans and moves the work Wk in the X direction (step S104). With this, a film containing the composition of the target material is formed on the lower surface of the substrate S in the workpiece Wk. Furthermore, a reactive gas (for example, oxygen) may be further supplied to the plasma space PL to form a film (for example, a metal oxide film) containing the components of the target 512 and the components of the reactive gas.

The transport mechanism 30 scans and moves the workpiece Wk, whereby the splashing position of the film-forming particles on the lower surface of the substrate S can be changed to form a film on the entire substrate S. The scanning movement of this workpiece Wk continues for a predetermined time (step S105). A film with a predetermined thickness is formed on the surface (lower surface) of the substrate S. The film-formed workpiece Wk formed on the substrate S is sent out to the outside (step S106). Then, if there is a workpiece Wk to be processed next (YES in step S107), it returns to step S103 to receive a new workpiece Wk and executes the same film forming process as described above. If there is no workpiece to be processed (NO in step S107), an end process (step S108) is performed to move each part of the device to a state where the operation can be ended (step S108) to end a series of operations.

Hereinafter, the output control of the high-frequency power supply 572 will be described. In this film forming apparatus 1, a mixed plasma of magnetron plasma and inductively coupled plasma is generated near the target 512. As a result, the target surface is sputtered to form a film on the substrate S. At this time, a part of the film-forming particles is also attached to each part in the device. Such attachments may also occur on the surfaces of the dielectrics 522, 532 of the inductively coupled antennas 52, 53 and this situation may cause the performance of the inductively coupled antennas 52, 53 to decrease. Specifically, the density of the inductively coupled plasma generated by the inductively coupled antennas 52 and 53 decreases. Especially in the case of the occurrence of conductive attachments, since it acts as a shield against the electromagnetic boundary generated by the antenna, its influence is significant.

In the case where the inductive coupling plasma is generated by the inductive coupling antennas 52 and 53, the impedance relative to the load of the high-frequency power supply 572 is the combined impedance of the impedance of the inductive coupling antennas 52 and 53 and the plasma impedance. Since the plasma impedance changes according to the plasma density, the load impedance changes as the attachment to the inductively coupled antennas 52 and 53 increases. However, the load impedance observed from the high-frequency power supply 572 will not change by the matching devices 575 and 576.

On the other hand, the plasma impedance also becomes part of the load relative to the cathode power supply 571. The decrease in plasma density due to the attachment to the inductively coupled antennas 52 and 53 is related to the increase in load impedance observed from the cathode power supply 571. This situation reduces the stability of the cathode current and cathode voltage. The cathode current is mainly a factor that affects the film formation speed, and the cathode voltage is a factor that affects the film quality. Therefore, in order to stably maintain the film formation speed and film quality during the continuous film formation, the film formation is performed while the film formation process requires less change in both the cathode current and the cathode voltage.

As described above, as the cathode power supply 571, various control methods of constant power control, constant current control, and constant voltage control can be adopted. However, neither of them can stably maintain both the cathode current and the cathode voltage. The reason is as follows: the cathode current and the cathode voltage are related to each other via the load impedance. Therefore, according to the change in plasma impedance accompanying the change in plasma density, if one of the cathode current and the cathode voltage is to be an appropriate value under the control of the cathode power supply 571, the other will be far from the appropriate value.

Therefore, in this embodiment, the plasma density is stabilized by changing the high-frequency power supplied to the inductively coupled antennas 52 and 53. Specifically, based on the measurement result of at least one of the cathode current and the cathode voltage indicating the magnitude of the cathode power, the change in plasma impedance is indirectly detected, and based on the result, the high-frequency power supply 572 controls the high-frequency power to be output size.

If the plasma density becomes higher, the sputtering amount of the target 512 increases, and therefore, the cathode current also increases. Conversely, if the density decreases, the cathode current decreases. That is, the decrease in cathode current under the conditions of constant voltage control or constant power control cathode power supply 571 refers to a decrease in plasma density. In addition, if the plasma impedance increases due to the decrease in plasma density, the cathode voltage also increases. That is, the increase in the cathode voltage under the condition of the constant current control or the constant power control cathode power supply 571 indicates the decrease in plasma density.

In the present embodiment, by adjusting the power supplied to the inductively coupled antennas 52 and 53, the density of the inductively coupled plasma that may change due to the contamination of the inductively coupled antennas 52 and 53 due to the attached matter is stabilized. Thereby, even when the dirt of the inductive coupling antennas 52 and 53 becomes serious, the load observed from the cathode power supply 571 can be kept fixed. With this control, the cathode current, cathode voltage, and cathode power expressed in the form of these products are kept constant. As a result, both the cathode current and the cathode voltage are stable, and the film formation can be continued while the film formation speed and film quality are stabilized.

The degree of dirt of the inductively coupled antennas 52 and 53 increases irreversibly with time. Therefore, if the power supply is fixed, the plasma density will gradually decrease, and accordingly, the plasma resistance will increase with time. Therefore, it is considered that in normal use, the high-frequency power supplied to the inductively coupled antennas 52 and 53 increases with time. In other words, if the high-frequency power increases with time to compensate for the decrease in plasma density accompanying the intensification of the dirt of the inductively coupled antennas 52 and 53, the load observed from the cathode power supply 571 can be kept fixed, making both the cathode current and the cathode voltage stable.

Furthermore, as described above, the plasma density can also be estimated from the measurement results of the plasma luminous intensity near the surface of the target 512. However, from the viewpoint of measurement accuracy and stability of results, it is considered better to set the measurement result of the cathode current or cathode voltage as the control input. It is better to use the measurement result of the luminous intensity of plasma to detect It should be coupled with antennas 52, 53 where the dirt is serious, or the condition that a stable plasma cannot be generated due to the failure of any part of the device.

In this embodiment, the cathode current or the cathode voltage is used as the control input, and the high-frequency power supply 572 controls the output power. More specifically, the output power of the high-frequency power supply 572 is controlled to supplement the target value or target range in which the measurement value set as the control input is predetermined. When the cathode current or the cathode voltage is set as the control input, the output power of the high-frequency power supply 572 is determined based on the result of detecting the power supply from the cathode power supply 571 to the sputtering cathode 51.

6 is a diagram showing the relationship between the control method of the cathode power supply and the control input that can be used for the high-frequency power supply. In the figure, the "○" mark indicates that the physical quantity is used as the control input of the high-frequency power supply 572 and the output control of the cathode power supply 571 matches. The "matching" mentioned here refers to those who can be suitably used as control inputs corresponding to the control mode. On the other hand, the "-" mark indicates that the control of the high-frequency power supply 572 using the physical quantity as the control input does not match the output control of the cathode power supply 571.

As shown in column A, when the output is controlled so that the cathode power supply 571 becomes constant current control, that is, the cathode current is fixed, the high-frequency power supply 572 can determine the high-frequency output using the cathode voltage as the control input. In this case, the output of the high-frequency power supply 572 is controlled so that the measured value of the cathode voltage becomes the target value (or within the target range, the same below). Since the cathode current is subjected to constant current control by the cathode power supply 571, as a result, both the cathode current and the cathode voltage are maintained at the target value.

Since the output of the cathode power supply 571 is controlled by constant current, the cathode current and plasma density are managed to an appropriate value. Therefore, even if these physical quantities are used as the control input of the high-frequency power supply 572, the proper cathode voltage cannot be maintained.

As shown in column B, the output is controlled to make the cathode power supply 571 constant In the case of voltage control, that is, when the cathode voltage is fixed, the high-frequency power supply 572 can determine the high-frequency output using the cathode current as the control input. In this case, the output of the high-frequency power supply 572 is controlled so that the measured value of the cathode current becomes the target value. Since the cathode voltage is subjected to constant voltage control by the cathode power supply 571, as a result, both the cathode voltage and the cathode current are maintained at the target values.

As shown in column C, since the output of the cathode power supply 571 is controlled by a constant voltage, the cathode voltage and the plasma density are managed to appropriate values. Therefore, even if the measured values of these physical quantities are used as the control input of the high-frequency power supply 572, the proper cathode current cannot be maintained.

When the output is controlled so that the cathode power supply 571 becomes constant power control, that is, the product of the cathode current and the cathode voltage is fixed, each value of the cathode current and the cathode voltage may become unstable. However, by adjusting the high-frequency output of the high-frequency power supply 572 to stabilize either, the other can also become stable. That is, any measured value of the cathode current and the cathode voltage can also be used as a control input of the high-frequency power supply 572.

7 is a flowchart showing an example of output control processing in a high-frequency power supply. Here, the control operation when the cathode power supply 571 performs constant voltage control and the high-frequency power supply 572 uses the cathode current as a control input is exemplified. However, for the control method of the cathode power supply 571 and the case where the physical quantity of the high-frequency power supply 572 becoming the control input is different from this, the processing flow can also be made with the same idea. This processing may be executed by a controller (not shown) built into the high-frequency power supply 572, for example. In addition, the CPU 91 or the film forming process control unit 95 provided in the control unit 90 of the film forming apparatus 1 can execute this process and provide an output instruction to the high-frequency power supply 572.

The high-frequency voltage and current set in advance are output from the high-frequency power source 572, and the application to the inductively coupled antennas 52 and 53 is started (step S201). Then, by interposing in The current measuring unit 573 between the cathode power supply 571 and the sputtering cathode 51 measures and obtains the value of the cathode current (step S202). When the current value exceeds a predetermined target value (YES in step S203), the voltage and current applied to the inductively coupled antennas 52, 53 are reduced by the amount corresponding to the excess (step S204). On the other hand, when the current value does not satisfy the target value (YES in step S205), the voltage and current applied to the inductively coupled antennas 52, 53 increase by a magnitude corresponding to the shortage (step S206). If the cathode current is consistent with the target value (NO in steps S203 and S205), the current high-frequency output is maintained. After that, the acquisition of the cathode current value and the adjustment of the high-frequency power output accompanying it are continuously performed.

By this processing, the cathode current flowing from the cathode power supply 571 to the sputtering cathode 51 is maintained at a fixed value. The cathode voltage is controlled by a constant voltage by the cathode power supply 571. Therefore, as a result, both the cathode current and the cathode voltage remain constant, and the power injected into the sputtering cathode 51 becomes constant. By this, the film-forming speed and the film quality of the film-forming film become stable.

FIG. 8 is a diagram illustrating the effect of the output control process. As shown in the graph on the upper side of FIG. 8, in a state where constant voltage control is performed such that the cathode voltage becomes the target value Vt, the case where the cathode current changes from the target value It to the current value Ia is considered. As shown in the lower curve of FIG. 8, the high-frequency power supply 572 is configured in such a manner that the larger the cathode current, the lower the high-frequency power output. When it is detected that the cathode current decreases from the target value It to the current value Ia, the high-frequency power supply 572 increases the high-frequency power output from the initial value Po to the value Pa. By this, the plasma density in the plasma space PL increases, the plasma impedance decreases, and the cathode current changes in the increasing direction. In this way, the cathode current will be maintained at the target value It.

FIG. 9 is a diagram illustrating a case where a constant current control is performed on a cathode current, and the cathode voltage is used as a control input. In this case, as shown by the curve on the lower side of Figure 9, The high-frequency power supply 572 is configured as follows: the higher the cathode voltage, the higher the high-frequency power output. Therefore, as shown in the upper graph of FIG. 9, when the cathode voltage rises from the target value Vt to the value Vb, the high-frequency power supply 572 increases the high-frequency power output from the initial value Po to the value Pb. The increase in cathode voltage under constant current control is caused by the increase in plasma impedance due to the decrease in plasma density. Therefore, by increasing the high-frequency power and increasing the plasma density to reduce the plasma impedance, the cathode voltage can be restored. In this way, the cathode voltage is maintained at the target value Vt.

In addition, in FIG. 8 and FIG. 9, in order to explain the principle, high-frequency power is depicted linearly with respect to the control input, but these may also have a non-linear relationship. In addition, in the case where the output of the cathode power supply 571 is controlled by constant power, the relationship between the current and the voltage in the upper curve of each of FIGS. 8 and 9 becomes a relationship represented by a parabola. To facilitate this situation, the output of the high-frequency power is adjusted by the same principle as in FIG. 8 or FIG. 9 to stabilize one of the cathode current and the cathode voltage, whereby the other is also uniquely determined.

In addition, in FIGS. 8 and 9, the target values It and Vt of the cathode voltage and the cathode current are set to unique values, respectively. However, as indicated by the additional symbols ΔI and ΔV in the figure, it can also be specified as a target range with a fixed width.

Here, the example of the cathode current changing in the direction of decrease in constant voltage control (FIG. 8) and the example of changing the cathode voltage in the direction of rising in constant current control (FIG. 9) were taken as examples Instructions. In these cases, the high-frequency power is changed in the direction of increase. The reasons for listing such examples are as described above. That is, changes in plasma density due to attachments to the inductively coupled antennas 52 and 53 generally occur in a direction that decreases with time. Therefore, due to the increase in plasma resistance, the cathode current changes in the direction of decrease, and the cathode voltage changes in the direction of increase.

If the focus is on dealing with the contamination of the inductively coupled antennas 52 and 53 due to attachments, in other words, it may be as follows. As long as the output from the high-frequency power supply 572 is controlled so that in the initial stage of less dirt, the high-frequency power supplied to the inductive coupling antennas 52 and 53 is relatively small, the supply power gradually becomes larger as the dirt becomes serious. Therefore, for example, a configuration may be considered in which the output of high-frequency power is gradually increased based on a predetermined schedule, not based on the measured values of voltage and current. However, from the viewpoint of the stability of control, as described above, it is more effective to use the measured value of the cathode current or the cathode voltage as the output control of the control input.

In addition, the output control processing of the present embodiment illustrated in FIG. 7 is a processing content that can cope with both the increase and decrease of the physical quantity used as the control input. Therefore, it is possible to cope with changes in plasma density caused by various reasons different from the dirt of the inductive coupling antennas 52 and 53. With this, the film formation with a stable film formation speed and a stable film quality can be carried out continuously.

As described above, this embodiment is a plasma sputtering film forming apparatus 1 including inductively coupled antennas 52 and 53 as a source of inductively coupled plasma. In the film forming apparatus 1, the magnitude of the high-frequency power supplied to the inductively coupled antennas 52 and 53 is controlled based on the measurement result of the cathode current or cathode voltage supplied from the cathode power supply 571 to the pair of sputtering cathodes 51. Therefore, the decrease in plasma density due to the dirt of the antenna is suppressed by the adjustment of high-frequency power. Therefore, the film formation can be performed while maintaining the cathode current and the cathode voltage supplied from the pair of sputtering cathodes 51 of the cathode power supply 571 at appropriate values.

The cathode current is a factor that affects the film formation speed. In addition, the cathode voltage is a factor that affects the film quality (more specifically, the film density) of the film formed. By performing film formation under appropriate control of these conditions, it is possible to suppress variations in film formation speed and film quality to continuously perform stable film formation. Therefore, a film with good film quality can be stably obtained.

Furthermore, if the dirt of the antenna becomes serious, even by the above control, it may not be possible to generate stable plasma. In this state, the device may be damaged by continuously increasing the high-frequency power. For example, the matchers 575, 576 may be damaged due to overcurrent. In order to avoid such problems, it is better to use a means to directly detect the presence or absence of plasma generation in the plasma space PL. For example, a technique for measuring the luminous intensity of plasma can be used as described above.

As described above, in the above embodiment, the sputtering cathode 51 functions as the "cathode" of the present invention. Moreover, the conveyance mechanism 30, especially the conveyance roller 31 functions as the "substrate holding part" of this invention. In addition, the inductive coupling antennas 52 and 53 both function as the "high-frequency antenna" of the present invention. Moreover, in the inductively coupled antennas 52 and 53, the conductors 521 and 531 correspond to the "linear conductor" of the present invention, and the dielectric substances 522 and 532 correspond to the "dielectric layer" of the present invention.

In addition, the present invention is not limited to the above-mentioned embodiment, and various changes other than those described above can be made as long as they do not deviate from the purpose. For example, in the above embodiment, two sets of inductively coupled antennas 52 and 53 are disposed in the vacuum chamber 10 with one set of sputtering cathodes 51 interposed. However, the arrangement of the sputtering cathode and the inductively coupled antenna of the sputtering source is not limited to this. For example, the arrangement may be as follows.

10A to 10C are diagrams showing modified examples of the sputtering source. Here, only the arrangement of the sputtering cathode and the inductively coupled antenna in each part constituting the film forming apparatus is shown, but the other constitutions provided in the above embodiments are also appropriately arranged. In the modification shown in FIG. 10A, two sets of sputtering cathodes 612 and 613 are arranged with one set of inductively coupled antenna 611 interposed therebetween. In addition, in the modification shown in FIG. 10B, two sets of inductively coupled antennas 623 and 624 are arranged via two sets of sputtering cathodes 621 and 622 arranged in an array. Furthermore, in the modification shown in FIG. 10C, two sets of sputtering cathodes 631, 632 and three sets of inductively coupled antennas 633,634,635 alternately arranged.

According to these configurations, inductive coupling plasma is generated around the sputtering cathode by supplying high-frequency power to the inductive coupling antenna and cathode power to the sputtering cathode. By this, sputtering of the target and film formation on the substrate are realized.

In addition, the present invention can be applied even to a plasma sputtering film forming apparatus having a configuration in which the magnetic circuit is removed from the above-mentioned configurations. Specifically, the present invention can also be applied to a device in the form of generating an inductively coupled plasma by forming a high-frequency electric field between a high-frequency antenna and a cathode electrode without using magnetron. In this type of device, the plasma density variation caused by the dirt of the antenna has a more significant effect on the film formation. Therefore, the effect obtained by controlling the high-frequency power based on the measurement result of the cathode current or the cathode voltage as described above is greater.

Furthermore, in the above-described embodiment, a flat cathode formed with a target in a flat plate shape is used as a sputtering cathode, and the target is fixed in a vacuum chamber. On the other hand, in order to eliminate the deterioration of the utilization efficiency of the target due to the local consumption of the target, a rotating cathode method in which the target is formed into a cylindrical shape and rotates may also be used. That is to say, in the film-forming device which is convenient for this rotating cathode method, the problem of lowering the plasma density caused by the dirt of the high-frequency antenna still remains. Therefore, by applying the same high-frequency power control as in the above embodiment, more stable film formation with excellent film quality can be performed.

FIG. 11 is a diagram showing a configuration example of a rotary cathode type film forming apparatus. In FIG. 11, the same symbols as those of the film forming apparatus 1 shown in FIG. 1 are provided with the same symbols, and descriptions are omitted. In addition, the description of the configuration of the control system is also omitted. This film forming apparatus 1a is provided with a sputtering source 70 having a cathode of a rotating cathode system instead of the sputtering source 50 of the film forming apparatus 1 shown in FIG.

The sputtering source 70 includes: a pair of rotating cathodes 71 and 72; The magnet units 73, 74 inside the rotary cathodes 71, 72; the rotary drive parts 75, 76 that hold the rotary cathodes 71, 72 on one side, and the rotations on the other side; and induction for generating a high-frequency electric field in the vacuum chamber 10 Coupling antenna 77. Among them, the inductive coupling antenna 77 is the same as the inductive coupling antenna 52 described above, and has a structure in which the surface of the conductor 771 is covered with a dielectric 772, and its functions are also equivalent.

The rotating cathode 71 and the magnet unit 73 integrally constitute a magnetron rotating cathode. Similarly, the rotating cathode 72 and the magnet unit 74 integrally constitute a magnetron-type rotating cathode. In this way, the film forming apparatus 1a has a pair of magnetron-type rotating cathodes arranged at different positions in the X direction. A pair of magnetron-type rotating cathodes have symmetrical shapes on the YZ plane, but the basic structure is the same.

The rotating cathode 71 (72) includes: a cylindrical base member 711 (721) with the Y direction orthogonal to the paper surface of FIG. 11 as the axial direction and the longitudinal direction; a target 712 (722) covering the outer periphery of the base member 711 (721) ). The base member 711 (721) is rotatably supported around the central axis by a bearing portion (not shown) provided in the rotation driving portion 75 (76) corresponding to both end portions in the Y direction. The base member 711 (721) is a conductor and supplies appropriate cathode power from a cathode power source (not shown).

The magnet unit 73 (74) disposed inside the rotating cathode 71 (72) is provided with: a yoke 731 (741) formed of magnetic material such as permeable steel; a plurality of magnets provided on the yoke 731 (741), namely Central magnet 732 (742); and peripheral magnet 733 (743) arranged to surround the central magnet. The yoke 731 is a flat plate member extending in the Y direction, and is arranged to face the inner circumference of the rotating cathode 71.

On the upper surface of the yoke 731, a center magnet 732 extending in the Y direction is arranged on the center line along the longitudinal direction (Y direction). In addition, a ring-shaped (ring-shaped) peripheral magnet surrounding the center magnet 732 is provided on the outer edge of the upper surface of the yoke 731 733. The central magnet 732 and the peripheral magnet 733 are, for example, permanent magnets. The polarities of the central magnet 732 and the peripheral magnet 733 facing the inner circumferential side of the rotating cathode 71 are different from each other.

One end of the fixing member 734 (744) is fixed to the lower surface of the yoke 731 (741), and the other end of the fixing member 734 (744) is mounted on a rod-shaped support extending in the Y direction at the center of the rotating cathode 71 (72) Member 735 (745). The supporting member 735 (745) does not rotate by the rotation of the rotating cathode 71 (72), so the position of the fixing member 734 (744) is also fixed. The fixing member 734 provided on the rotating cathode 71 is upward from the supporting member 735, but is arranged obliquely toward the other rotating cathode 72 side. On the other hand, the fixing member 744 provided on the rotating cathode 72 is upwardly arranged from the supporting member 745 and is inclined to the other rotating cathode 71 side. Therefore, the magnet units 73 and 74 collectively form a static magnetic field in the plasma space PL.

An inductive coupling antenna 77 is provided on the bottom surface of the vacuum chamber 10 so as to protrude toward the space between the pair of rotating cathodes 71 and 72. The inductive coupling antenna 77 is supplied with high-frequency power from a high-frequency power source (not shown) via a matching device. Thereby, inductively coupled plasma is generated in the plasma space PL. The rotating cathodes 71, 72, the magnet units 73, 74, and the inductive coupling antenna 77 all extend along the Y direction perpendicular to the paper surface of FIG. Therefore, the plasma space PL also becomes a space region having a shape extending long in the Y direction along the surfaces of the rotating cathodes 71 and 72.

That is, in the film forming apparatus 1a that is convenient for such a configuration, a high-density plasma formed by overlapping the magnetron plasma and the inductive coupling plasma is also generated in the plasma space PL. As a result, the surfaces of the targets 712 and 722 are sputtered to form a film. At this time, if film-forming particles are attached to the inductively coupled antenna 77 and the surface is contaminated, the density of the inductively coupled plasma will decrease, resulting in an increase in the plasma impedance in the plasma space PL. To suppress the resulting cathode current And the change of cathode voltage can be controlled by the above-mentioned high-frequency power. The same applies to the configuration without magnetron.

In addition, in the above embodiment, the current measuring unit 573 and the voltage measuring unit 574 for measuring the cathode current and the cathode voltage are provided in the power supply unit 57. However, if the cathode power supply 571 incorporates these measurement functions for output control and can take out the measurement results to the outside, the measurement function can also be used as a current and voltage measurement unit.

In the above description, although the upper limit of high-frequency power is not specifically mentioned, the amount of power that the high-frequency power supply 572, the inductively coupled antennas 52 and 53 and the matching devices 575 and 576 can handle is limited. Therefore, for the output power of the high-frequency power supply 572, an upper limit value may be specified in advance, and output exceeding the upper limit value is prohibited. In this way, even in the case of serious dirt on the antenna, it is possible to prevent excessive power input to compensate for damage to the device in advance.

As described above, as a specific embodiment is explained as an example, in the present invention, the high-frequency antenna may be a structure having a linear conductor covered with a dielectric layer and wound less than one turn. The high-frequency antenna of this structure has low inductance and can inject large high-frequency power. Therefore, high-density inductively coupled plasma can be stably generated.

Also, for example, as the cathode in the present invention, a magnetron cathode can be applied. That is, when the magnetron plasma generated by the magnetron cathode overlaps with the inductive coupling plasma generated by the high-frequency antenna, the decrease in the density of the inductive coupling plasma caused by the dirt of the high-frequency antenna also makes the cathode power unstable Reason. That is, it is convenient for such a device. By applying the present invention, the cathode current and the cathode voltage can be stabilized without being affected by the dirt of the antenna.

Also, for example, the present invention may be configured as follows: constant voltage control is applied to the voltage provided by the cathode, or constant power control is applied to the power provided by the cathode. The measured value of the current flowing through the cathode controls the high frequency power. According to this configuration, by stabilizing the current flowing through the cathode, as a result, both the current and voltage of the cathode are maintained at appropriate values.

Alternatively, a configuration may be adopted in which the current flowing through the cathode is subjected to constant current control, or the power supplied to the cathode is subjected to constant power control, and the high-frequency power is controlled based on the measured value of the voltage of the cathode. According to this configuration, by stabilizing the voltage applied to the cathode, as a result, both the current and voltage of the cathode are maintained at appropriate values.

Also, for example, if the configuration of controlling the high-frequency power in such a way that the measured value of the current or voltage of the cathode is within a predetermined appropriate range, as a result of the above control, both the current and voltage of the cathode can be maintained in the appropriate range .

In addition, for example, it may be configured to increase the high-frequency power supplied to the high-frequency antenna with time. The dirt caused by the attachment to the high-frequency antenna acts in a manner that reduces the density of the plasma, and as a result, the impedance of the plasma increases. In order to maintain a fixed plasma impedance, it is desirable to compensate for the decrease in plasma density by increasing the high-frequency power supplied to the high-frequency antenna with time.

(Industry availability)

The present invention can be preferably applied to the entire technique of forming a film on a substrate by plasma sputtering using inductively coupled plasma generated by a high-frequency antenna.

1‧‧‧film forming device

10‧‧‧Vacuum chamber

31‧‧‧Conveying roller

51‧‧‧Sputtering cathode

52, 53‧‧‧ Inductively coupled antenna

54‧‧‧Sputtering gas supply nozzle

55‧‧‧Chimney

56‧‧‧Gas Supply Department

57‧‧‧Power Department

58‧‧‧cooling mechanism

59‧‧‧Optical Probe

511‧‧‧support plate

514‧‧‧Housing

571‧‧‧ Cathode power supply

572‧‧‧High frequency power supply

573‧‧‧Current Measurement Department

574‧‧‧Voltage Measurement Department

575、576‧‧‧matcher

PL‧‧‧Plasma space

S‧‧‧Substrate

T‧‧‧Tray

SP‧‧‧Internal space

Wk‧‧‧Workpiece

Claims (10)

A film-forming device that forms a film by plasma sputtering on a substrate, and includes: a vacuum chamber; a cathode, which is provided in the vacuum chamber, and a target; and a high-frequency antenna, which is located in the vacuum chamber The chamber is arranged near the target; the substrate holding portion holds the substrate against the target in the vacuum chamber; the gas supply portion supplies sputtering gas into the vacuum chamber; and the cathode power supply The cathode supplies predetermined cathode power; a high-frequency power supply that supplies high-frequency power to the high-frequency antenna to generate inductively coupled plasma; and a matcher that is electrically interposed between the high-frequency antenna and the high-frequency power supply Impedance matching; and the high-frequency power supply adjusts the magnitude of the high-frequency power supplied to the high-frequency antenna based on the measurement result of at least one of the current flowing through the cathode and the voltage of the cathode to convert the power of the cathode Control to a specific value. The film forming apparatus according to claim 1, wherein the high-frequency antenna has a structure in which a linear conductor covered by a dielectric layer is wound for less than one turn. The film forming apparatus according to claim 1, wherein the cathode is a magnetron cathode. The film forming apparatus according to claim 1, wherein the cathode power supply is a constant voltage control voltage supplied to the cathode, or a constant power control power supplied to the cathode; the high frequency power supply is based on a measured value of a current flowing through the cathode And control the above-mentioned high-frequency power. The film forming apparatus according to claim 1, wherein the cathode power supply is a constant current control flow The power supplied to the cathode through the current of the cathode or constant power control; the high-frequency power supply controls the high-frequency power based on the measured value of the voltage of the cathode. The film forming apparatus according to claim 4 or 5, wherein the high-frequency power source controls the high-frequency power so that the measured value becomes within a predetermined appropriate range. A film forming method, which forms a film by plasma sputtering on a substrate, and includes: a step of arranging a cathode with a target, a high-frequency antenna, and the substrate in the vacuum chamber; supplying sputtering to the vacuum chamber The step of injecting gas; and the step of supplying predetermined cathode power to the cathode from the power supply unit, and supplying high-frequency power to the high-frequency antenna via a matching device, and generating an inductively coupled plasma in the vacuum chamber; and the power supply unit is based on The measurement result of at least one of the current flowing through the cathode and the voltage of the cathode controls the high-frequency power supplied to the high-frequency antenna. The film forming method according to claim 7, wherein the power supply unit controls the voltage supplied to the cathode by constant voltage, or the power supplied to the cathode by constant power, and controls the above based on the measured value of the current flowing through the cathode High frequency power. The film forming method according to claim 7, wherein the power supply unit controls the current flowing through the cathode by constant current, or the power supplied to the cathode by constant power, and controls the high frequency based on the measured value of the voltage of the cathode electricity. The film forming method according to claim 8 or 9, wherein the power supply unit controls the high-frequency power so that the measured value becomes within a predetermined suitable range.

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