JP2019183235A - Sputtering device and sputtering method - Google Patents

Abstract

To suppress a thin film deposited by pulse sputtering from varying in film thickness.SOLUTION: A sputtering device 10 has: a vacuum chamber 12 which houses a substrate S and a target material T; a DC power supply 14 which outputs a DC current to the target material; a pulsing unit 16 which converts the DC current of the DC power supply into a pulse current; an ammeter 18 which measures a current value of the DC current flowing from the DC power supply to the pulsing unit; a power control unit 20 which performs, based upon the measured current value, feedback control over the output voltage of the DC power supply so that the output electric power of the DC power supply is kept constant; a pulse detector 22 which measures the pulse current to detect a predetermined pulse current; and a film deposition control unit 24 which determines film deposition end timing based upon the output voltage of the DC power supply, the current value measured by the ammeter, and the detection timing of the predetermined pulse current detected by the pulse detector. The DC power supply stops outputting the DC current at the film deposition end timing.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a sputtering apparatus and a sputtering method for forming a film on a substrate such as a semiconductor wafer.

  In the manufacture of semiconductor devices, a thin film such as a metal or an oxide is formed on a substrate, and the thin film is formed in a desired pattern to form electrodes, wirings, resistors, capacitors, and the like.

  In recent years, for example, the use environment of devices has become higher, and higher density has been demanded for passivation thin films that protect devices. Thus, there is an increasing need for a technique for forming a high-density or highly crystalline thin film with high film thickness accuracy.

  In thin film formation of devices, DC sputtering, high frequency sputtering, etc. are often used from the viewpoint of production speed and production stability. In the case of forming a thin film of a compound, reactive sputtering is used in which a target material as a raw material is reacted with a reactive gas. However, depending on the combination of the target material and the reactive gas, a sufficient reaction rate cannot be obtained. Especially when forming a nitride film using nitrogen gas, the general sputtering has high density or high crystallinity. It is difficult to obtain a thin film.

  Conventionally, as one of film forming means for forming such a high-density and highly-oriented thin film, there is pulse sputtering in which a pulse voltage is applied between a substrate to be formed and a target material (for example, Patent Document 1). reference.).

Japanese Patent No. 5490368

  An object of the present disclosure is to suppress variations in the thickness of a thin film formed by pulse sputtering.

In order to solve the above-described problem, according to one aspect of the present disclosure,
A vacuum chamber for accommodating the substrate to be deposited and the target material in a state of facing each other;
A direct current power source for outputting a direct current to the target material;
A pulsing unit that converts a direct current from the direct current power source toward the target material into a pulse current;
An ammeter for measuring a current value of a direct current from the direct current power source toward the pulse unit;
A power supply control device that feedback-controls the output voltage of the DC power supply so that the output power of the DC power supply is kept constant based on the current value measured by the ammeter;
A pulse detector disposed between the target material and the pulsing unit and measuring the pulse current to detect a predetermined pulse current;
Deposition control for determining the film formation end timing based on the output voltage of the DC power supply, the current value measured by the ammeter, and the detection timing of the predetermined pulse current detected by the pulse detector An apparatus,
A sputtering apparatus is provided in which the DC power supply stops the output of DC current at the film formation end timing.

According to another aspect of the present disclosure,
A sputtering method for forming a film on a substrate,
In the vacuum chamber, the substrate and the target material are arranged opposite to each other,
Output direct current from the direct current power source to the target material,
Measure the current value of the direct current from the direct current power source toward the target material,
Convert DC current after measurement to pulse current,
Feedback control of the output voltage of the DC power supply so that the output power of the DC power supply is kept constant based on the measured current value,
Measure the pulse current to detect a predetermined pulse current,
Based on the output voltage value of the DC power supply, the measured current value, and the detection timing of the predetermined pulse current, the film formation end timing is determined,
A sputtering method is provided in which the direct current output of the direct current power supply is stopped at the film formation end timing.

  According to the present disclosure, variations in the thickness of a thin film formed by pulse sputtering can be suppressed.

Schematic configuration diagram of a sputtering apparatus according to the first embodiment of the present disclosure Timing chart showing relationship between pulse output, DC power supply, pulse current, average power, and integrated power in sputtering apparatus according to Embodiment 1. The figure which shows the relationship between the elapsed time after the DC power source is turned on and the average power Detailed view showing change in average power immediately after the DC power supply is turned on The figure which shows the pulse current in the timing Pa shown to FIG. 3B The figure which shows the pulse current in the timing Pb shown to FIG. 3B The figure which shows the pulse current in the timing Pc shown to FIG. 3B The figure which shows the pulse current in the timing Pd shown to FIG. 3B The figure which shows the relationship between the elapsed time after the DC power supply is turned ON and the integrated power Detailed view showing change in integrated power immediately after the DC power supply is turned on Schematic configuration diagram of a sputtering apparatus according to the second embodiment of the present disclosure The figure which shows the erosion which displaces on the target material by the eccentric rotation of the magnet Diagram showing the relationship between the angular position of the magnet and the plasma discharge voltage Timing chart showing relationship between pulse output, DC power supply, pulse current, average power, and integrated power in sputtering apparatus according to Embodiment 2. The figure which shows the relationship between the elapsed time after the DC power supply is turned ON and the output voltage of the DC power supply The figure which shows the waveform of the DC voltage at the time of the stable state shown to FIG. 10A The figure which shows the relationship between the elapsed time after the DC power supply is turned ON and the current measured by the ammeter The figure which shows the waveform of the electric current in the stable state shown to FIG. 11A The figure which shows the relationship between the elapsed time after the DC power source is turned on and the average power The figure which shows the waveform of the average electric power at the time of the stable state shown to FIG. 12A

  A sputtering apparatus according to an aspect of the present disclosure includes a vacuum chamber that accommodates a substrate to be deposited and a target material facing each other, a DC power source that outputs a DC current to the target material, and the DC power source from the DC power source. Based on a pulsating unit that converts a direct current directed to a target material into a pulsed current, an ammeter that measures a current value of a direct current directed from the direct current power source to the pulsed unit, and a current value measured by the ammeter The power supply control device that feedback-controls the output voltage of the DC power supply so that the output power of the DC power supply is maintained constant, and is arranged between the target material and the pulse unit, and measures the pulse current A pulse detector for detecting a predetermined pulse current, an output voltage of the DC power source, and a current value measured by the ammeter A film formation control device that determines a film formation end timing based on the detection timing of the predetermined pulse current detected by the pulse detector, and the DC power source is at the film formation end timing. , Stop direct current output.

  For example, the pulse detector may detect the timing at which the current value of the pulse current from the pulsing unit toward the target material exceeds a predetermined threshold as the detection timing of the predetermined pulse current.

  For example, the power supply control device calculates an average power based on the output voltage value of the DC power supply and the current value measured by the ammeter, and the film formation control device detects the predetermined pulse current after the detection timing. The average power at the time may be integrated, and the timing at which the integrated value reaches a predetermined threshold may be determined as the film formation end timing.

  For example, the sputtering apparatus has a magnet disposed so as to face the back surface of the target material opposite to the substrate side surface, and a rotation center line intersecting the back surface of the target material. A rotating device that rotates the magnet eccentrically.

  For example, the sputtering apparatus includes a position detection sensor that detects passage of a predetermined position of the magnet that is eccentrically rotated by the rotation apparatus, and the DC power supply is connected to a DC current at a detection timing of the position detection sensor. Output may be started.

  A sputtering method according to another aspect of the present disclosure is a sputtering method for forming a film on a substrate, wherein the substrate and the target material are arranged to face each other in a vacuum chamber, and a direct current is output from the direct current power source to the target material. The current value of the direct current from the direct current power source toward the target material is measured, the direct current after measurement is converted into a pulse current, and the output power of the direct current power source is maintained constant based on the measured current value. Feedback control of the output voltage of the DC power supply, and measuring the pulse current to detect a predetermined pulse current, the output voltage value of the DC power supply, the measured current value, and the predetermined pulse The film formation end timing is determined based on the current detection timing, and the DC current output of the DC power supply is stopped at the film formation end timing.

  Hereinafter, a sputtering apparatus and a sputtering method according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a sputtering apparatus according to the first embodiment.

  As shown in FIG. 1, a sputtering apparatus 10 according to the first embodiment includes a vacuum chamber 12 that houses a substrate S such as a semiconductor wafer and a target material T, and a DC power supply 14 that outputs DC power to the target material T. And a pulsing unit 16 that converts a direct current from the direct current power source 14 toward the target material T into a pulse current.

  Further, the sputtering apparatus 10 includes an ammeter 18 that measures a current value of a direct current from the DC power source 14 toward the pulse unit 16, and a power source that feedback-controls the DC power source 14 based on the current value measured by the ammeter 18. The control device 20 includes a pulse detector 22 that is disposed between the target material T and the pulsing unit 16 and detects a predetermined pulse current.

  Further, the sputtering apparatus 10 finishes the film formation based on the output voltage value of the DC power supply 14, the current value measured by the ammeter 18, and the detection timing of a predetermined pulse current detected by the pulse detector 22. A film formation control device 24 that determines timing is included.

  The vacuum chamber 12 is configured to accommodate the substrate S to be deposited and the target material T in a state of facing each other. The vacuum chamber 12 is connected to a vacuum pump 28 through a gate valve 26. The vacuum chamber 12 is decompressed to a vacuum state by being sucked by the vacuum pump 28. The gate valve 26 is configured to be adjustable in its opening, and the degree of vacuum in the vacuum chamber 12 is adjusted by adjusting the opening.

  Further, the vacuum chamber 12 is connected to a gas supply source 30. The gas supply source 30 is configured to supply a gas necessary for sputtering to the vacuum chamber 12 at a constant speed. The gas supplied by the gas supply source 30 is, for example, a reactive gas that reacts with the target material T such as nitrogen or oxygen, a rare gas such as argon, or a mixed gas of a reactive gas and a rare gas.

  Furthermore, the vacuum chamber 12 includes a backing plate 32 that holds the target material T therein. In addition, the vacuum chamber 12 includes a substrate holder 34 that is disposed to face the backing plate 32 with a space therebetween and holds the substrate S. In the case of the first embodiment, the backing plate 32 and the substrate holder 34 face each other in the vertical direction, and the backing plate 32 is positioned above the substrate holder 34. Thereby, the target material T and the substrate S face each other in the vertical direction.

  The target material T held by the backing plate 32 is an inorganic material such as a metal material or a semiconductor material.

  In the case of the first embodiment, the vacuum chamber 12 includes a magnet 38 that forms a magnetic field 36 on the surface of the target material T. One end of the magnet 38 is connected to the yoke 40. Further, the magnet 38 and the yoke 40 are disposed in the vacuum chamber 12 so as to face the target material T with the backing plate 32 interposed therebetween and so that the other end of the magnet 38 faces the backing plate 32. The magnet 38 and the yoke 40 constitute a magnetic circuit, thereby suppressing the formation of a magnetic field on the side opposite to the target material T. It should be noted that one or more magnets 38 may be used, which may be permanent magnets or electromagnets. With the magnet 38 and the yoke 40, the plasma is concentrated on the surface of the target material T on the substrate S side at a position where a magnetic field parallel to the surface is generated, thereby improving the deposition rate. The position where such plasma concentrates is called erosion. When the erosion is fixed at a specific position, only the corresponding target material T is consumed, and the entire target material T cannot be used efficiently, so that the magnet 38 and the yoke 40 are placed on the surface of the target material T. The position of the erosion may be shifted by moving in parallel.

  The DC power source 14 is connected to the target material T via the ammeter 18, the pulse unit 16, the pulse detector 22, and the backing plate 32, and outputs a DC current to the target material T via these.

  The pulsing unit 16 is connected to an ammeter 18 and a pulse detector 22 and is configured to convert a direct current from the direct current power source 14 toward the target material T into a pulse current. The pulsing unit 16 is a substrate on which a circuit including, for example, a capacitor and a semiconductor switching element is formed. By intermittently outputting the current stored in the capacitor by turning on and off the semiconductor switching element, the pulse unit 16 pulses the current to the target material T (outputs a pulse current). The pulsing unit 16 is configured to receive a control signal from the film formation control device 24, as will be described in detail later.

  The ammeter 18 is connected to the DC power source 14 and the pulse unit 16 and measures the current value of the DC current from the DC power source 14 toward the pulse unit 16. The ammeter 18 is configured to output the measured current value as a signal to the power supply control device 20.

  The power supply control device 20 is a power supply controller that controls on / off of the DC power supply 14 and adjusts the output voltage to control the current output of the DC power supply 14. Further, the power supply control device 20 is configured to receive an ammeter side signal indicating the current measurement value output from the ammeter 18 and a control signal (details will be described later) from the film formation control device 24. .

  The power supply control device 20 is configured to output a control signal for turning on / off the DC power supply 14 and a control signal for adjusting the output voltage to the DC power supply 14 to control the DC power supply 14. Yes. In the case of the first embodiment, the power supply control device 20 feedback-controls the output voltage of the DC power supply 14 so that the output power of the DC power supply 14 is kept constant based on the current value measured by the ammeter 18. To do. Further, in the case of the first embodiment, the power supply control device 20 calculates the average power as the effective value of the output power of the DC power supply 14 based on the output voltage value of the DC power supply 14 and the current value measured by the ammeter 18. Is calculated. The power supply control device 20 is configured to output an average power signal indicating the calculated average power to the film formation control device 24.

  The pulse detector 22 is disposed between the target material T and the pulsing unit 16 and is configured to detect a predetermined pulse current. In the case of the first embodiment, the pulse detector 22 measures the pulse current flowing from the pulsing unit 16 toward the target material T, and at the timing when the current value exceeding a predetermined threshold is measured, that is, plasma discharge. Is configured to output a plasma discharge start signal indicating the start of plasma discharge to the film formation control device 24 at the timing when a predetermined pulse current is detected. The pulse measurement cycle is, for example, 1% or less of the total film formation time. When film thickness accuracy is required, the pulse measurement cycle is desirably a cycle of 0.1% or less of the total film formation time. For example, when the total film formation time is about 100 seconds, the pulse measurement period is usually in the range of 0.1 seconds to 1.0 seconds. The predetermined threshold is desirably a value in the range of 10% to 20% with respect to the current value when the film formation measured in advance is stably performed.

  The film formation control device 24 is a controller that controls film formation, and includes, for example, a CPU and a storage device that stores a program. The film formation control is executed by the CPU driving according to the program. The film formation control device 24 is connected to the pulse unit 16, the power supply control device 20, and the pulse detector 22. Thereby, the film formation control device 24 outputs a control signal to the pulsing unit 16 and the power supply control device 20, and receives the average power signal from the power supply control device 20 and the plasma discharge start signal from the pulse detector 22. To do.

  Further, the film formation control device 24 determines the film formation end timing based on the output voltage of the DC power supply 14 and the current measured by the ammeter 18 after the detection timing of the predetermined pulse current by the pulse detector 22. In the case of the first embodiment, the film formation control device 24 integrates the average power (average power calculated by the power supply control device 20) after the detection timing of a predetermined pulse current, and the integrated value of the average power is a predetermined value. The timing at which this threshold value is exceeded is determined as the film formation end timing. Then, the film formation control device 24 stops the pulse unit 16 (outputs a stop signal to the pulse unit 16 as a control signal) and stops the DC power source 14 (as a control signal) at the film formation end timing. A stop signal is output to the power supply control device 20, and the power supply control device 20 stops the DC power supply 14). This completes the film formation. The reason for controlling the film formation in this way will be described later.

  From here, the pulse sputtering which the sputtering apparatus 10 which concerns on this Embodiment 1 performs is demonstrated.

  First, the substrate S and the target material T are set in the vacuum chamber 12.

  Next, the vacuum chamber 28 is depressurized to a vacuum state by operating the vacuum pump 28. When the predetermined degree of vacuum is reached, the gas supply source 30 is operated to introduce gas into the vacuum chamber 12, and the opening of the gate valve 26 is adjusted so that the inside of the vacuum chamber 12 has a predetermined gas pressure. .

  When the inside of the vacuum chamber 12 reaches a predetermined gas pressure, the DC power source 14 and the pulsing unit 16 start operating. The direct current from the direct current power source 14 is converted into a pulse current by the pulse unit 16, and the pulse current is output to the target material T. Thereby, a part of the gas in the vacuum chamber 12 is dissociated and plasma is generated.

  In a period in which a direct current is output to the target material T (a period in which the pulse current is not zero), ions separated from the gas by the plasma collide with the target material T, and thereby particles jump out of the target material T. Then, the particles of the target material T that jump out adhere to the substrate S and are deposited. At the same time, the gas or plasma in the vacuum chamber 12 reacts with the target material T on the substrate S.

  In a period in which a direct current is not output to the target material T (a period in which the pulse current is zero), the gas and plasma in the vacuum chamber 12 react with the target material T on the substrate S, and the target material T and the gas are A bonded dense compound is formed.

  Thus, a direct current is intermittently output to the target material T, that is, a thin film having a high density and a high orientation is formed on the substrate S by pulse sputtering.

  Next, the flow until the end of the pulse sputtering performed by the sputtering apparatus 10 according to the first embodiment, that is, the flow until the film formation ends will be described with reference to FIG.

  FIG. 2 is a timing chart showing the relationship among pulse output, DC power supply, pulse current, average power, and integrated power in the sputtering apparatus according to the first embodiment.

  As shown in FIG. 2, before the DC power supply 14 is turned on, the pulse unit 16 starts pulse output. At this time, no pulse current is output to the target material T.

  Next, the DC power supply 14 is turned on by the film formation control device 24 (via the power supply control device 20), and output of DC current is started. Thereby, a pulse current starts to be output to the target material T. The ammeter 18 measures the current flowing from the DC power source 14 to the pulsing unit 16. The power supply control device 20 calculates power from the current value measured by the ammeter 18 and the output voltage value of the DC power supply 14. In the case of the first embodiment, time averaged average power is calculated instead of power per pulse. The power supply control device 20 also feedback-controls the output voltage of the DC power supply 14 based on the current value measured by the ammeter 18 in order to maintain the output power of the DC power supply 14 substantially constant. The power supply control device 20 further outputs the calculated average power to the film formation control device 24.

  As shown in FIG. 2, when the output of the pulse current to the target material T is started, the pulse detector 22 starts measuring the pulse current flowing from the pulsing unit 16 toward the target material T. When the pulse detector 22 measures a current value exceeding a predetermined threshold value and detects a predetermined pulse current at which plasma discharge starts to occur, a film deposition control is performed on a signal indicating the start of plasma discharge (plasma discharge start signal). Output to the device 24.

  The film formation control device 24 starts integration of the average power calculated by the power supply control device 20 from the detection timing (plasma discharge start timing) of a predetermined pulse current by the pulse detector 22. When the integrated value of the average power reaches the predetermined threshold value Wt corresponding to the predetermined film thickness, the film formation control device 24 ends the film formation. In order to stop the plasma discharge and finish the film formation, the film formation control device 24 directs the direct current to the direct current power supply 14 via the power supply control device 20 at the same time as or after the pulse output unit 16 stops the pulse output. Stops current output.

  Furthermore, a specific description will be given of detection of a predetermined pulse current at which plasma discharge starts to occur by the pulse detector 22.

  FIG. 3A is a diagram showing the relationship between the elapsed time after the DC power source is turned on and the average power, and FIG. 3B is a detailed diagram showing the change in average power immediately after the DC power source is turned on. 4A to 4D are diagrams showing pulse currents at a plurality of timings Pa to Pd shown in FIG. 3B. FIG. 5A is a diagram showing the relationship between the elapsed time since the DC power source is turned on and the integrated power, and FIG. 5B is a detailed diagram showing the change in the integrated power immediately after the DC power source is turned on.

  As shown in FIGS. 3A and 3B, the average power is not stable immediately after the DC power supply 14 is turned on, and it takes about 10 seconds for the average power to stabilize at a predetermined value (for example, 1000 W). The time from when the DC power source 14 is turned on until the average power is stabilized differs every time the sputtering process, which is a batch process, is performed due to plasma fluctuation or the like, that is, it is not constant and varies. In such a transitional period until the average power is stabilized, the thin film formation rate (target material particle deposition rate) is slower and varies than the subsequent period in which the average power is stable.

  For example, in the case of the change in average power shown in FIG. 3B, the average power increases by timing Pa, but no pulse current is generated as shown in FIG. 4A. The average power starts to rise again after timing Pb after dropping once, reaches about half (500 W) of the stable value at timing Pc, and reaches the stable value (1000 W) at timing Pd. As shown in FIGS. 4B to 4D, the peak value of the pulse current rises from the timing Pb to the timing Pd, and the peak value of the pulse current becomes stable after the timing Pd.

  For example, as shown in FIG. 4B, the pulse detector 22 detects a predetermined pulse current exceeding a predetermined threshold It at timing Pb. The detection timing is set as the plasma discharge start timing, and the film formation control device 24 starts integrating the average power as shown in FIGS. 5A and 5B. Since the output power of the DC power supply 14 is maintained substantially constant by the power supply control device 20, the integrated power after the timing Pb increases in proportion to the elapsed time. Then, as shown in FIG. 5A, assuming that a thin film having a desired film thickness is formed on the substrate S at the timing when the integrated power reaches the predetermined threshold value Wt, the film formation control device 24 finishes the film formation. Let It should be noted that the relationship between the integrated power from the generation timing of the predetermined pulse current and the film thickness is obtained theoretically or experimentally in advance.

  There is a variation in the time from when the DC power supply 14 is turned on until the timing at which the pulse detector 22 detects a current value exceeding the predetermined threshold It (predetermined timing for detecting the predetermined pulse current). However, since a plasma discharge necessary for film formation actually starts at a predetermined pulse current detection timing, the film thickness increases in proportion to an increase in integrated power after the plasma discharge starts to occur. Therefore, the integrated power from the detection timing of the predetermined pulse current required for forming a thin film with a desired film thickness is constant with little variation. A thin film having a stable thickness can be formed by using the integrated power from the detection timing of such a pulse current.

  In contrast, when the film thickness control is performed in the elapsed time after the DC power supply 14 is turned on, there is a variation in the time from when the DC power supply 14 is turned on until a predetermined pulse current where plasma discharge actually starts to occur is generated. Therefore, the film thickness varies. The sputtering apparatus 10 according to the first embodiment forms a thin film having a stable thickness without being affected by the time from when the DC power supply 14 is turned on until a predetermined pulse current is generated. Can be membrane.

  According to the sputtering apparatus 10 according to the first embodiment, it is possible to accurately detect the timing at which the plasma discharge is started and the deposition of the thin film is actually started by the pulse detector 22. By controlling the film thickness based on the integrated power from the detection timing, a thin film having a stable film thickness can be formed. As a result, variations in the thickness of the thin film formed by pulse sputtering can be suppressed.

(Embodiment 2)
The second embodiment is different from the first embodiment described above in that the magnet and the yoke rotate eccentrically. Therefore, the second embodiment will be described focusing on the different points. In addition, the same code | symbol is attached | subjected to the component in this Embodiment 2 substantially the same as the component in the above-mentioned Embodiment 1. FIG.

  FIG. 6 is a schematic configuration diagram of the sputtering apparatus according to the second embodiment.

  As shown in FIG. 6, in the sputtering apparatus 110 of the second embodiment, the magnet 38 and the yoke 40 are disposed so as to face the back surface of the target material T opposite to the substrate side surface, and the target material T Is rotated eccentrically around a rotation center line that intersects the back surface of the rotation center (orthogonal in the case of the second embodiment).

  Specifically, the rotation center line of the eccentric rotation passes through the center of the circular target material T, and the rotation shaft of the rotating device 142 such as a motor is connected to the position of the yoke 40 that is eccentric from the shape center position of the yoke 40. Has been. A rotation control device 144 that controls the rotation device 142 and is connected to the film formation control device 124 is provided. Further, a position detection sensor 146 that detects the angular position of the eccentric rotating magnet 38 and is connected to the film formation control device 124 is provided. The position detection sensor 146 detects the magnet 38 when the eccentric rotating magnet 38 passes a predetermined position in the vacuum chamber 12 and outputs a detection signal to the film formation control device 124 at the detection timing.

  The eccentric rotation of the magnet 38 (plus the yoke 40) will be described with reference to FIG.

  FIG. 7 shows the erosion that is displaced on the target material by the eccentric rotation of the magnet.

  As shown in FIG. 7, when the magnet 38 rotates eccentrically, the erosion E is displaced so as to circulate on the target material T. Cross hatching indicates the current erosion E. At this time, the magnet 38 exists at an angular position of 90 degrees with respect to the eccentric rotation center (the angular position at which the magnet 38 is detected by the position detection sensor 146 is 0). Degrees). The broken line indicates the position of erosion E when the magnet 38 is positioned at 0 degrees, 180 degrees, and 270 degrees, respectively.

  As shown in FIG. 7, when the erosion E is displaced by the eccentric rotation of the magnet 38, the target material T is consumed evenly throughout the entire area without being consumed locally. Thereby, the whole target material T can be efficiently used for pulse sputtering.

  Moreover, when the magnet 38 rotates eccentrically, the internal environment in the vacuum chamber 12 changes periodically, that is, the shape of the empty space in the vacuum chamber 12 changes periodically. As a result, the plasma discharge environment periodically changes such that the gas flow periodically changes.

  FIG. 8 shows the relationship between the angular position of the magnet and the plasma discharge voltage.

  As shown in FIG. 8, the discharge voltage at which plasma is ignited also periodically changes in synchronization with the periodic change in the angular position of the magnet 38. As a result, a state where discharge is easy (state where the discharge voltage is low) and a state where discharge is difficult (state where the discharge voltage is high) occur alternately.

  Therefore, when the DC power supply 14 is turned on when the angular position of the magnet 38 is different (when the output of the DC current is started), the time from the ON timing to the timing when the plasma is ignited is different, and as a result, as described above. Even if the film thickness is controlled based on the integrated power from the detection timing (plasma discharge start timing) of a predetermined pulse current, the film thickness may vary.

  FIG. 9 is a timing diagram showing the relationship among pulse output, DC power supply, control current, average power, and integrated power in the sputtering apparatus according to the second embodiment.

  As shown in FIG. 9, before the DC power supply 14 is turned on, the pulse unit 16 starts to output pulses. At this time, no pulse current is output to the target material T.

  Next, the rotation control device 144 controls the rotation device 142 to rotate the magnet 38 eccentrically at a constant rotation speed. Thereby, the angular position of the magnet 38 changes periodically.

  At the timing when the position detection sensor 146 detects the magnet 38 whose angular position is zero, the DC power supply 14 is turned on by the film formation control device 124 and the output of the DC current is started. Thereby, a pulse current starts to be output to the target material T. The ammeter 18 measures the current flowing from the DC power source 14 to the pulsing unit 16. The power supply control device 20 calculates the average power from the current measurement value measured by the ammeter 18 and the output voltage value of the DC power supply 14, and outputs the calculated average power to the film formation control device 124.

  As shown in FIG. 9, when the output of the pulse current to the target material T is started, the pulse detector 22 starts measuring the pulse current flowing from the pulse unit 16 toward the target material T. When the pulse detector 22 measures a current value exceeding a predetermined threshold value and detects a predetermined pulse current at which plasma discharge starts to occur, a film deposition control is performed on a signal indicating the start of plasma discharge (plasma discharge start signal). Output to the device 124.

  The film formation control device 124 starts integration of the average power calculated by the power supply control device 20 from the detection timing of the predetermined pulse current (plasma discharge start timing) by the pulse detector 22. When the integrated value of the average power reaches the predetermined threshold value Wt corresponding to the predetermined film thickness, the film formation control device 124 ends the film formation.

  FIG. 10A is a diagram showing the relationship between the elapsed time since the DC power source was turned on and the output voltage of the DC power source, and FIG. 10B is a diagram showing the waveform of the DC voltage in the stable state shown in FIG. 10A. . 11A is a diagram showing the relationship between the elapsed time since the DC power source was turned on and the current measured by the ammeter, and FIG. 11B shows the waveform of the current in the stable state shown in FIG. 11A. FIG. 12A is a diagram showing the relationship between the elapsed time since the DC power source is turned on and the average power, and FIG. 12B is a diagram showing the waveform of the average power in the stable state shown in FIG. 12A.

  As shown in FIG. 12A, the behavior of the average power immediately after the DC power supply 14 is turned on is the same as that in the first embodiment. The output voltage waveform of the DC power supply 14 when the average power is in a substantially stable state (1000 V) is affected by a periodic change in the plasma discharge voltage synchronized with the eccentric rotation of the magnet 38, as shown in FIG. 10B. ing. That is, the output voltage fluctuates with a cycle similar to the cycle f of the magnet 38. Similarly, as shown in FIG. 11B, the current measured by the ammeter 18 also fluctuates. As a result, as shown in FIG. 12B, the average power maintained constant by feedback control of the output voltage of the DC power supply 14 based on the measured current of the ammeter 18 by the power supply control device 20 also has a small fluctuation range. Things are fluctuating.

  In the case of the second embodiment, it is desirable that the pulse measurement period of the pulse detector 22 is set to ½ or less of the rotation period of the magnet 38. Thereby, it is possible to cope with changes in current and voltage due to rotation of the magnet 38. For example, when the rotation of the magnet 38 is 20 rpm, the rotation period is 3 seconds, so the pulse measurement period is preferably 1.5 seconds or less.

  According to the second embodiment as described above, since the DC power supply 14 is turned on at the timing when the eccentric rotating magnet 38 is present at the angular position of zero degrees, variations in plasma ignition timing are suppressed (different). (Compared to the case where the DC power supply 14 is turned on when the magnet 38 is present at an angular position).

  Therefore, even when the magnet 38 is eccentrically rotated, the timing at which the plasma discharge is started and the deposition of the thin film is actually started can be accurately detected by the pulse detector 22 as in the first embodiment. Further, by controlling the film thickness based on the integrated power from the detection timing, a thin film having a stable film thickness can be formed. As a result, variations in the thickness of the thin film formed by pulse sputtering can be suppressed.

  As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description are provided. Accordingly, among the components described in the accompanying drawings and detailed description, not only the components essential for solving the problem, but also the components not essential for solving the problem in order to exemplify the above-described technique. Elements can also be included. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

  Moreover, since the above-mentioned embodiment is for demonstrating the technique in this indication, a various change, substitution, addition, abbreviation, etc. can be performed in a claim or its equivalent range.

  For example, the embodiment of the present disclosure is not limited to a sputtering apparatus in which a substrate to be deposited and a target material are arranged to face each other in the vertical direction, but for example, to a sputtering apparatus in which a substrate and a target material are arranged to face each other in the horizontal direction. Is also applicable.

DESCRIPTION OF SYMBOLS 10 Sputtering device 12 Vacuum chamber 14 DC power supply 16 Pulse unit 18 Ammeter 20 Power supply control device 22 Pulse detector 24 Deposition control device S Substrate T Target material

Claims (6)

A vacuum chamber for accommodating the substrate to be deposited and the target material in a state of facing each other;
A direct current power source for outputting a direct current to the target material;
A pulsing unit that converts a direct current from the direct current power source toward the target material into a pulse current;
An ammeter for measuring a current value of a direct current from the direct current power source toward the pulse unit;
A power supply control device that feedback-controls the output voltage of the DC power supply so that the output power of the DC power supply is kept constant based on the current value measured by the ammeter;
A pulse detector disposed between the target material and the pulsing unit and measuring the pulse current to detect a predetermined pulse current;
Deposition control for determining the film formation end timing based on the output voltage of the DC power supply, the current value measured by the ammeter, and the detection timing of the predetermined pulse current detected by the pulse detector An apparatus,
The sputtering apparatus, wherein the DC power supply stops the output of DC current at the film formation end timing.   The pulse detector detects a timing at which a current value of a pulse current from the pulsing unit toward the target material exceeds a predetermined threshold as a detection timing of the predetermined pulse current. Sputtering equipment. The power supply control device calculates an average power based on an output voltage value of the DC power supply and a current value measured by the ammeter,
The film formation control device integrates the average power after the detection timing of the predetermined pulse current, and determines a timing when the integrated value reaches a predetermined threshold as the film formation end timing. The sputtering apparatus according to 1 or 2. A magnet arranged to face the back surface opposite to the substrate side surface in the target material;
4. The sputtering apparatus according to claim 1, further comprising: a rotating device that eccentrically rotates the magnet about a rotation center line that intersects the back surface of the target material. 5. A position detection sensor for detecting passage of a predetermined position of the magnet that is eccentrically rotated by the rotating device;
The sputtering apparatus according to claim 4, wherein the DC power supply starts outputting a DC current at a detection timing of the position detection sensor. A sputtering method for forming a film on a substrate,
In the vacuum chamber, the substrate and the target material are arranged opposite to each other,
Output direct current from the direct current power source to the target material,
Measure the current value of the direct current from the direct current power source toward the target material,
Convert DC current after measurement to pulse current,
Feedback control of the output voltage of the DC power supply so that the output power of the DC power supply is kept constant based on the measured current value,
Measure the pulse current to detect a predetermined pulse current,
Based on the output voltage value of the DC power supply, the measured current value, and the detection timing of the predetermined pulse current, the film formation end timing is determined,
A sputtering method in which the direct current output of the direct current power supply is stopped at the film formation end timing.

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