JP7065362B2 - Sputtering equipment and sputtering method - Google Patents

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, thin films such as metals and oxides are formed on a substrate, and the thin films are formed in a desired pattern to form electrodes, wirings, resistors, capacitors, and the like.

In recent years, for example, the usage environment of a device has become hotter, and a higher density has been required for a passivation thin film that protects the device. As described above, there is an increasing need for a technique for forming a thin film having high density or high crystallinity with high film thickness accuracy.

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

Conventionally, as one of the 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 film thickness of a thin film formed by pulse sputtering.

In order to solve the above-mentioned problems, according to one aspect of the present disclosure,
A vacuum chamber that accommodates the substrate to be film-formed and the target material in a state of facing each other,
A DC power supply that outputs a DC current to the target material,
A pulsed unit that converts a direct current from the direct current to the target material into a pulse current,
An ammeter that measures the current value of the DC current from the DC power supply to the pulsed 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 arranged between the target material and the pulsed unit to measure the pulse current and detect a predetermined pulse current.
Film formation control that determines 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. With the device,
A sputtering apparatus is provided in which the direct current power supply stops the output of the direct current at the end timing of the film formation.

Further, according to another aspect of the present disclosure.
It is a sputtering method for forming a film on a substrate.
The substrate and the target material are arranged so as to face each other in the vacuum chamber.
A direct current is output from the direct current power supply to the target material,
The current value of the direct current from the direct current power source to the target material is measured, and the current value is measured.
Converts the measured direct current into pulse current and converts it into pulse current.
The output voltage of the DC power supply is feedback-controlled so that the output power of the DC power supply is kept constant based on the measured current value.
The pulse current is measured to detect a predetermined pulse current, and the pulse current is detected.
The film formation end timing is determined based on the output voltage value of the DC power supply, the measured current value, and the detection timing of the predetermined pulse current.
A sputtering method is provided in which the DC current output of the DC power supply is stopped at the film formation end timing.

According to the present disclosure, it is possible to suppress variations in the film thickness of the thin film formed by pulse sputtering.

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

The sputtering apparatus according to one aspect of the present disclosure includes a vacuum chamber that accommodates a substrate to be deposited and a target material in a state of facing each other, a DC power supply that outputs a DC current to the target material, and the DC power supply. Based on a pulsed unit that converts a DC current toward the target material into a pulsed current, a current meter that measures the current value of the DC current from the DC power supply to the pulsed unit, and a current value measured by the current meter. 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 maintained constant, and is arranged between the target material and the pulsed unit to measure the pulse current. A pulse detector that detects a predetermined pulse current, an output voltage of the DC power supply, a current value measured by the current meter, and a detection timing of the predetermined pulse current detected by the pulse detector. Based on the above, the film forming control device for determining the film forming end timing is provided, and the DC power supply stops the output of the DC current at the film forming end timing.

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

For example, the power supply control device calculates the 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 after the detection timing of the predetermined pulse current. The average power in the above may be integrated, and the timing at which the integrated value reaches a predetermined threshold value may be determined as the film formation end timing.

For example, the sputtering apparatus is centered on a magnet arranged so as to face the back surface of the target material opposite to the side surface of the substrate and a rotation center line intersecting the back surface of the target material. It may have a rotating device that rotates the magnet eccentrically.

For example, the sputter device has a position detection sensor that detects the passage of a predetermined position of the magnet that is eccentrically rotated by the rotation device, and the DC power supply receives a direct current at the detection timing of the position detection sensor. You may start the output.

The sputtering method according to another aspect of the present disclosure is a sputtering method for forming a film on a substrate, in which the substrate and the target material are arranged to face each other in a vacuum chamber, and a DC current is output from the DC power supply to the target material. , The current value of the DC current from the DC power supply to the target material is measured, the measured DC current is converted into a pulse current, and the output power of the DC power supply is maintained constant based on the measured current value. The output voltage of the DC power supply is feedback-controlled, the pulse current is measured to detect a predetermined pulse current, the output voltage value of the DC power supply, the measured current value, and the predetermined pulse are detected. 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, the sputtering apparatus and the sputtering method according to the 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, the sputtering apparatus 10 according to the first embodiment has a vacuum chamber 12 for accommodating a substrate S such as a semiconductor wafer and a target material T, and a DC power supply 14 for outputting DC power to the target material T. And a pulsed 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 sputter device 10 is a current meter 18 that measures the current value of the DC current from the DC power supply 14 to the pulsed unit 16, and a power supply that feedback-controls the DC power supply 14 based on the current value measured by the ammeter 18. It has a control device 20 and a pulse detector 22 arranged between the target material T and the pulsed unit 16 to detect a predetermined pulse current.

Further, the sputtering apparatus 10 completes 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 the predetermined pulse current detected by the pulse detector 22. It has a film forming control device 24 for determining the timing.

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

Further, the vacuum chamber 12 is connected to the gas supply source 30. The gas supply source 30 is configured to supply the gas required 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 the reaction gas and the rare gas.

Furthermore, the vacuum chamber 12 includes a backing plate 32 inside which holds the target material T. In addition, the vacuum chamber 12 includes a substrate holder 34 that is spaced apart from the backing plate 32 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 located above the substrate holder 34. As a result, the target material T and the substrate S face each other in the vertical direction.

The target material T held on 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 arranged 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 form a magnetic circuit, thereby suppressing the formation of a magnetic field on the side opposite to the target material T. The magnet 38 may be one or more, and may be a permanent magnet or an electromagnet. The magnet 38 and the yoke 40 concentrate the plasma 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 film forming speed. The position where such plasma is concentrated is called erosion. When the erosion is fixed at a specific position, only the portion of the target material T is consumed and the entire target material T cannot be used efficiently. Therefore, the magnet 38 and the yoke 40 are attached to the surface of the target material T. The position of the erosion may be shifted by moving it in parallel.

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

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

The ammeter 18 is connected to the DC power supply 14 and the pulsing unit 16, and measures the current value of the DC current from the DC power supply 14 to the pulsing unit 16. Further, 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 the 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 a current measurement value output from the ammeter 18 and a control signal (details will be described later) from the film formation control device 24. ..

Further, 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. There is. 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. do. Further, in the case of the first embodiment, the power supply control device 20 has an average power as an 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. Then, the power supply control device 20 is configured so as to output the average power signal indicating the calculated average power to the film formation control device 24.

The pulse detector 22 is arranged between the target material T and the pulse forming 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 pulsed unit 16 toward the target material T, and at the timing when the current value exceeding a predetermined threshold value is measured, that is, plasma discharge. Is configured to output a plasma discharge start signal indicating the start of plasma discharge to the film forming control device 24 at the timing when a predetermined pulse current at which the above starts to occur 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 preferably 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 cycle is usually in the range of 0.1 seconds to 1.0 seconds. It is desirable that the predetermined threshold value is 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 is composed of, for example, a CPU and a storage device that stores a program. The film formation control is executed by driving the CPU according to the program. Further, the film formation control device 24 is connected to the pulse forming unit 16, the power supply control device 20, and the pulse detector 22. As a result, the film formation control device 24 outputs a control signal to the pulse forming unit 16 and the power supply control device 20, and also receives the average power signal from the power supply control device 20 and the plasma discharge start signal from the pulse detector 22. 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 forming control device 24 integrates the average power (average power calculated by the power supply control device 20) after the detection timing of the predetermined pulse current, and the integrated value of the average power is predetermined. The timing when the threshold value of is exceeded is determined as the film formation end timing. Then, the film forming control device 24 stops the pulsed unit 16 (outputs a stop signal as a control signal to the pulsed unit 16) and stops the DC power supply 14 (as a control signal) at the film forming 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 executed by the sputtering apparatus 10 according to the first embodiment will be described.

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

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

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

During the period when the direct current is output to the target material T (the period when the pulse current is not zero), the ions separated from the gas by the plasma collide with the target material T, whereby the particles are ejected from the target material T. Then, the ejected particles of the target material T 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.

During the period when the direct current is not output to the target material T (the period when 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 brought into contact with each other. A dense, bound compound is formed.

By intermittently outputting the direct current to the target material T in this way, that is, by pulse sputtering, a thin film having high density and high orientation is formed on the substrate S.

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

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

As shown in FIG. 2, the pulsed unit 16 starts pulse output before the DC power supply 14 is turned on. At this time, the pulse current is not 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 the output of the DC current is started. As a result, the pulse current starts to be output to the target material T. The ammeter 18 measures the current flowing from the DC power supply 14 to the pulsed unit 16. The power supply control device 20 calculates the electric 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, the time-averaged average power is calculated instead of the 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 pulsed unit 16 toward the target material T. When the pulse detector 22 measures a current value exceeding a predetermined threshold value, it is assumed that a predetermined pulse current at which plasma discharge starts occurs is detected, and a signal indicating the start of plasma discharge (plasma discharge start signal) is controlled to form a film. Output to the device 24.

The film forming control device 24 starts integrating the average power calculated by the power supply control device 20 from the detection timing (plasma discharge start timing) of the predetermined pulse current by the pulse detector 22. The film formation control device 24 ends the film formation when the integrated value of the average power reaches a predetermined threshold value Wt corresponding to the predetermined film thickness. In order to stop the plasma discharge and finish the film formation, the film formation control device 24 stops the pulse output of the pulsed unit 16 and at the same time or thereafter, DC to the DC power supply 14 via the power supply control device 20. Stop the current output.

Further, the detection of a predetermined pulse current at which plasma discharge starts to occur by the pulse detector 22 will be specifically described.

FIG. 3A is a diagram showing the relationship between the elapsed time after the DC power supply is turned on and the average power, and FIG. 3B is a detailed diagram showing the change in the average power immediately after the DC power supply is turned on. 4A to 4D are diagrams showing pulse currents at a plurality of timings Pa to Pd shown in FIG. 3B. 5A is a diagram showing the relationship between the elapsed time after the DC power supply 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 supply 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 supply 14 is turned on until the average power stabilizes is different every time the sputtering process, which is a batch process, is executed due to the fluctuation of plasma or the like, that is, it is not constant and varies. In such a transitional period until the average power stabilizes, the thin film formation rate (the deposition rate of particles of the target material) is slower and varies than in the subsequent period when the average power stabilizes.

For example, in the case of the change in the average power shown in FIG. 3B, the average power increases by the timing Pa, but the pulse current is not generated as shown in FIG. 4A. The average power drops once and then starts to rise again after the timing Pb, reaches about half of the stable value (500 W) at the timing Pc, and reaches the stable value (1000 W) at the timing Pd. As shown in FIGS. 4B to 4D, the peak value of the pulse current increases from the timing Pb to the timing Pd, and the peak value of the pulse current stabilizes after the timing Pd.

For example, as shown in FIG. 4B, the pulse detector 22 detects a predetermined pulse current exceeding a predetermined threshold value It at the timing Pb. This detection timing is set as the plasma discharge start timing, and the film formation control device 24 starts to integrate 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 a predetermined threshold value Wt, the film forming control device 24 ends the film forming. Let me. The relationship between the integrated power and the film thickness from the timing of generation of a predetermined pulse current has been obtained theoretically or experimentally in advance.

There is a variation in the time from when the DC power supply 14 is turned on to the timing when the pulse detector 22 detects a current value exceeding a predetermined threshold value It (predetermined pulse current detection timing). However, since the plasma discharge required for film formation actually starts to occur at the detection timing of the predetermined pulse current, the film thickness increases in proportion to the increase in the 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 the thin film of a desired film thickness is constant with almost no variation. By utilizing the integrated power from the detection timing of such a pulse current, a thin film having a stable film thickness can be formed.

Unlike this, when the film thickness is controlled by the elapsed time after the DC power supply 14 is turned on, the time from when the DC power supply 14 is turned on until the predetermined pulse current at which the plasma discharge actually starts is generated varies. Due to the presence of, the film thickness varies. The sputtering apparatus 10 according to the first embodiment forms a thin film having a stable film thickness without being affected by a certain time from when the DC power supply 14 is turned on until a predetermined pulse current is generated. Can be filmed.

According to the sputtering apparatus 10 according to the first embodiment, the timing at which the plasma discharge starts and the thin film deposition actually starts can be accurately detected 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, it is possible to suppress variations in the film thickness of the thin film formed by pulse sputtering.

(Embodiment 2)
The second embodiment is different from the first embodiment in which the magnet and the yoke do not rotate in that the magnet and the yoke rotate eccentrically. Therefore, the second embodiment will be described focusing on the different points. The components in the second embodiment, which are substantially the same as the components in the first embodiment described above, are designated by the same reference numerals.

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 arranged so as to face the back surface of the target material T opposite to the side surface of the substrate, and the target material T is arranged. It is eccentrically rotated around the rotation center line that intersects the back surface of the magnet (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 axis of the rotating device 142 such as a motor is connected to the position of the yoke 40 eccentric from the shape center position of the yoke 40. Has been done. 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 magnet 38 that rotates eccentrically and is connected to the film formation control device 124 is provided. The position detection sensor 146 detects the magnet 38 when the magnet 38 during eccentric rotation passes a predetermined position in the vacuum chamber 12, and outputs a detection signal to the film forming 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. 7.

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

As shown in FIG. 7, the eccentric rotation of the magnet 38 causes the erosion E to be displaced so as to orbit on the target material T. The cross-hatching indicates the current erosion E, at which time the magnet 38 is at an angular position of 90 degrees with respect to the center of eccentric rotation (the angular position where the magnet 38 is detected by the position detection sensor 146 is 0). Degree). The broken line indicates the position of the erosion E when the magnet 38 is located at 0 degrees, 180 degrees, and 270 degrees, respectively.

As shown in FIG. 7, the displacement of the erosion E due to the eccentric rotation of the magnet 38 causes the target material T to be uniformly consumed as a whole without being locally consumed. As a result, the entire target material T can be efficiently used for pulse sputtering.

Further, the eccentric rotation of the magnet 38 causes the internal environment in the vacuum chamber 12 to change periodically, that is, the shape of the empty space in the vacuum chamber 12 changes periodically. As a result, the plasma discharge environment changes periodically, such as the gas flow changing periodically.

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

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

Therefore, if the DC power supply 14 is turned on (when the DC current output is started) when the angular position of the magnet 38 is different, the time from the ON timing to the plasma ignition timing 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 between the pulse output, the DC power supply, the Ars current, the average power, and the integrated power in the sputtering apparatus according to the second embodiment.

As shown in FIG. 9, the pulsed unit 16 starts pulse output before the DC power supply 14 is turned on. At this time, the pulse current is not 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. As a result, the angular position of the magnet 38 changes periodically.

At the timing when the magnet 38 whose angular position is zero is detected by the position detection sensor 146, the DC power supply 14 is turned on by the film formation control device 124, and the output of the DC current is started. As a result, the pulse current starts to be output to the target material T. The ammeter 18 measures the current flowing from the DC power supply 14 to the pulsed unit 16. The power supply control device 20 calculates an 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 pulsed unit 16 toward the target material T. When the pulse detector 22 measures a current value exceeding a predetermined threshold value, it is assumed that a predetermined pulse current at which plasma discharge starts occurs is detected, and a signal indicating the start of plasma discharge (plasma discharge start signal) is controlled to form a film. Output to device 124.

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

FIG. 10A is a diagram showing the relationship between the elapsed time since the DC power supply is turned on and the output voltage of the DC power supply, and FIG. 10B is a diagram showing the waveform of the DC voltage in the stable state shown in FIG. 10A. .. Further, FIG. 11A is a diagram showing the relationship between the elapsed time since the DC power 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. It is a figure. 12A is a diagram showing the relationship between the elapsed time since the DC power 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 of the first embodiment described above. As shown in FIG. 10B, 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 the periodic change of the discharge voltage of the plasma synchronized with the eccentric rotation of the magnet 38. ing. That is, the output voltage fluctuates in the same cycle as 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 fluctuation range of the average power maintained constant by feedback-controlling 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 is also small. Things are fluctuating.

In the case of the second embodiment, it is desirable that the pulse measurement cycle of the pulse detector 22 is ½ or less of the rotation cycle of the magnet 38. This makes it 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 cycle is 3 seconds, so that the pulse measurement cycle 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 exists at the angle position of zero degree, the variation in the ignition timing of the plasma is suppressed (different). Compared to the case where the DC power supply 14 is turned on when the magnet 38 is present at the angular position).

Therefore, even if the magnet 38 is eccentrically rotated, the pulse detector 22 can accurately detect the timing at which the plasma discharge starts and the thin film deposition actually starts, as in the first embodiment. Further, by controlling the film thickness based on the integrated power from the detection timing, it is possible to form a thin film having a stable film thickness. As a result, it is possible to suppress variations in the film thickness of the thin film formed by pulse sputtering.

As described above, an embodiment has been described as an example of the technique in the present disclosure. To that end, the accompanying drawings and detailed explanations have been provided. Therefore, among the components described in the attached drawings and the 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-mentioned technique. Elements can also be included. Therefore, the fact that those non-essential components are described in the accompanying drawings or detailed description should not immediately determine that those non-essential components are essential.

Further, since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent thereof.

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

10 Spattering device 12 Vacuum chamber 14 DC power supply 16 Pulse unit 18 Ammeter 20 Power supply control device 22 Pulse detector 24 Formation control device S Substrate T Target material

Claims (4)

A vacuum chamber that accommodates the substrate to be film-formed and the target material in a state of facing each other,
A DC power supply that outputs a DC current to the target material,
A pulsed unit that converts a direct current from the direct current to the target material into a pulse current,
An ammeter that measures the current value of the DC current from the DC power supply to the pulsed 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 arranged between the target material and the pulsed unit to measure the pulse current and detect a predetermined pulse current.
Film formation control that determines 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. With the device,
The DC power supply stops the output of the DC current at the end timing of the film formation, and the DC power supply stops the output of the DC current.
The pulse detector detects the timing at which the current value of the pulse current from the pulsed unit toward the target material exceeds a predetermined threshold value as the detection timing of the predetermined pulse current.
The power supply control device calculates the average power based on the output voltage value of the DC power supply and the 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 the timing at which the integrated value reaches a predetermined threshold value as the film formation end timing . ..
A magnet arranged so as to face the back surface of the target material opposite to the side surface of the substrate,
The sputtering device according to claim 1 , further comprising a rotating device for eccentric rotation of the magnet about a rotation center line intersecting the back surface of the target material.
It has a position detection sensor that detects the passage of a predetermined angular position of the magnet rotated eccentrically by the rotating device with respect to the rotation center line .
The spattering apparatus according to claim 2 , wherein the direct current power source starts to output a direct current at the detection timing when the position detection sensor detects the magnet that has passed the predetermined angle position .
It is a sputtering method for forming a film on a substrate.
The substrate and the target material are arranged so as to face each other in the vacuum chamber.
A direct current is output from the direct current power supply to the target material,
The current value of the direct current from the direct current power source to the target material is measured, and the current value is measured.
Converts the measured direct current into pulse current and converts it into pulse current.
The output voltage of the DC power supply is feedback-controlled so that the output power of the DC power supply is kept constant based on the measured current value.
The pulse current is measured to detect a predetermined pulse current, and the pulse current is detected.
The film formation end timing is determined based on the output voltage value of the DC power supply, the measured current value, and the detection timing of the predetermined pulse current.
At the end timing of the film formation, the DC current output of the DC power supply is stopped .
The timing at which the current value of the pulse current toward the target material exceeds a predetermined threshold value is detected as the detection timing of the predetermined pulse current.
The average power is calculated based on the output voltage value and the measured current value of the DC power supply.
A sputtering method in which the average power after the detection timing of the predetermined pulse current is integrated, and the timing at which the integrated value reaches a predetermined threshold value is determined as the film formation end timing .

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