JP2015040330A - Sputtering film deposition apparatus and sputtering film deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean a mask, while depositing a film.SOLUTION: A film deposition apparatus for generating plasma between a target 10 and the substrate 12 by applying a high-voltage cathode voltage to a cathode electrode, and depositing a film on a substrate 12 via a mask 11 includes a pulse bias power source 6 so that a pulsing negative voltage can be applied to the mask 11 in a film deposition step onto the substrate 12.

Description

  The present invention relates to a sputtering film forming apparatus for forming a film on a substrate opposed to a target through a mask, and more particularly to a sputtering film forming apparatus and a sputtering film forming method capable of cleaning a mask while forming a film. It is.

  In a conventional film forming apparatus, a film forming apparatus having a mask cleaning function has completed the deposition of an organic compound using a mask in a decompressed film forming chamber, and then brought the film forming chamber to atmospheric pressure, A high-frequency voltage is applied to the mask to excite the gas introduced into the film formation chamber to generate plasma, thereby removing the organic compound attached to the mask (see, for example, Patent Document 1).

JP 2012-197518 A

  However, in such a conventional film forming apparatus, since the mask cleaning is appropriately performed after the film formation on the substrate, the film cannot be formed during the mask cleaning, and the throughput of the film formation substrate is reduced. There was a problem.

  In view of the above, an object of the present invention is to provide a sputtering film forming apparatus and a sputtering film forming method capable of coping with such problems and cleaning a mask while forming a film.

  In order to achieve the above object, the sputtering film forming apparatus according to the first invention generates a plasma between a target and a substrate by applying a high cathode voltage to the cathode electrode, and forms a plasma on the substrate through a mask. A sputtering film forming apparatus for forming a film, comprising a pulse bias power source capable of applying a pulsed negative voltage to the mask during a film forming process on the substrate.

  Further, the sputtering film forming method according to the second invention is a sputtering film forming method in which a high voltage cathode voltage is applied to the cathode electrode to generate plasma between the target and the substrate, and the film is formed on the substrate through a mask. In the film forming process on the substrate, a pulsed negative voltage is applied to the mask.

  According to the present invention, a thin film deposited on the surface of the mask is inactivated by applying a pulsed negative voltage to the mask during the film formation process on the substrate performed by applying a high cathode voltage to the cathode electrode. It can be removed by striking with gas cations. Accordingly, the mask can be cleaned while the film is formed, and the throughput of the film formation substrate can be improved.

It is a front view which shows schematic structure of 1st Embodiment of the sputtering film-forming apparatus by this invention. It is a flowchart explaining the sputtering film-forming method by the said 1st Embodiment. 3 is a timing chart showing the application timing of the bias voltage in the first embodiment. It is a figure explaining the film-forming of the seasoning period in the said 1st Embodiment, (a) shows the time of film-forming start, (b) shows the state which film-forming advanced. It is explanatory drawing shown about the mask washing | cleaning in the sputtering film-forming by the said 1st Embodiment. It is a figure explaining after film-forming restart in the sputtering film-forming by the said 1st Embodiment, (a) shows the time of film-forming resumption, (b) shows the state which film-forming advanced further. It is a front view which shows schematic structure of 2nd Embodiment of the sputtering film-forming apparatus by this invention. It is a timing chart which shows the application timing of the bias voltage in the said 2nd Embodiment.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a front view showing a schematic configuration of a first embodiment of a sputtering film forming apparatus according to the present invention. This sputtering film forming apparatus is an RF sputtering apparatus that generates a plasma between a target and a substrate by applying a high-frequency voltage to a target holder, and forms a film on the substrate through a mask. 2, a substrate holder 3, a shutter 4, a high-frequency power source 5, and a pulse bias power source 6.

  The vacuum chamber 1 is a sealed container that forms a film forming chamber 7 therein, and includes a gas introduction port 8 and an exhaust port 9. Then, the air or sputtering gas in the film forming chamber 7 is exhausted by a vacuum pump (not shown) connected to the exhaust port 9 so that the inside of the film forming chamber 7 can be maintained at a certain degree of vacuum. ing. Further, a gas cylinder (not shown) of an inert gas such as argon (Ar) gas is connected to the gas introduction port 8 by a pipe so that the sputtering gas can be introduced into the film forming chamber 7. .

  A target holder 2 is disposed in the film forming chamber 7 of the vacuum chamber 1. The target holder 2 is used to fix and hold the target 10 and is formed of a metal material in a state of being electrically insulated from the vacuum chamber 1. Note that the target holder 2 may be provided with a water channel so that cooling water for cooling the target 10 can be introduced from the outside as needed.

  A substrate holder 3 is disposed in the film forming chamber 7 of the vacuum chamber 1 so as to face the target holder 2. The substrate holder 3 holds the substrate 12 in a state in which a mask 11 made of, for example, a resin film provided with a plurality of opening patterns is in close contact with the film formation surface of the substrate 12, and is formed of a metal material. Yes.

  Note that the mask 11 is not limited to a non-conductive material such as a resin film, and may be a conductive metal mask. In this case, when the thin film to be formed is a conductive film, either a non-conductive mask or a conductive metal mask may be used. In addition, when the thin film to be formed is a non-conductive film, it is possible to use a conductive metal mask or a composite mask in which a conductive thin film is deposited on the target side surface of the non-conductive mask. Good. In the description of this embodiment, the case where the thin film to be formed is a conductive film and the mask 11 is a non-conductive resin film will be described.

  The target holder 2 and the substrate holder 3 may be arranged in any manner in the film forming chamber 7 of the vacuum chamber 1. For example, the target holder 2 and the substrate holder 3 may be opposed to each other in the vertical direction, or may be arranged to be opposed to the left and right. However, when the mask 11 is made of a film as in the present embodiment, the target holder 2 and the substrate holder 3 are arranged vertically opposite to each other so that the substrate holder 3 is on the lower side, or on the vertical axis. It is desirable to incline and arrange them oppositely. Thereby, since the film mask 11 hangs down by its own weight, the mask 11 can be brought into close contact with the film formation surface of the substrate 12.

  A shutter 4 is provided between the target holder 2 and the substrate holder 3. The shutter 4 is for controlling the start and end timing of the film formation, and is provided so that the passage of the sputtered particles 19 flying from the target 10 toward the substrate 12 can be opened and closed. That is, when the shutter 4 moves in the direction of arrow A shown in FIG. 1 and the passage of the sputtered particles 19 is opened, film formation starts, and the shutter 4 moves in the direction of arrow B shown in FIG. When is closed, the film formation is completed. Thereby, the film thickness of the thin film pattern formed can be controlled. The state where the passage of the sputtered particles 19 is closed by the shutter 4 is referred to as “the shutter 4 is closed”, and the state where the passage of the sputtered particles 19 is opened is referred to as “the shutter 4 is opened”. .

  A high frequency power source (RF power source) 5 is provided in electrical connection with the target holder 2. The high-frequency power source 5 supplies a high-frequency power of 13.56 MHz to the target holder 2 and applies a high-frequency voltage (RF voltage) to the target holder 2 to generate plasma between the target 10 and the substrate 12. And a high-frequency matching unit (not shown) for adjusting the high-frequency power is provided. In this case, the target holder 2 side is a cathode electrode, and the substrate holder 3 side is a ground electrode (anode electrode). In FIG. 1, reference numeral 13 denotes a bypass capacitor connected in series to the target holder 2, and reference numeral 14 denotes, for example, a portion of the target holder 2 other than the portion of the target 10 where the anode ions face the substrate 12. This is a shield member for preventing collision, and an opening 15 is provided corresponding to the central region of the target 10.

  A pulse bias power supply 6 is provided on the surface of the mask 11 on the target 10 side so as to be energized. The pulse bias power source 6 is driven in synchronization with the cathode voltage, and is driven to be turned on when the cathode voltage is positive to output a pulsed negative voltage and to apply a bias voltage to the mask 11. . In this case, the pulse bias power source 6 is inserted between the bias electrode 16 contacting the surface of the mask 11 and the bias electrode 16 and the pulse bias power source 6 as shown in FIG. Is connected in series with a limiting resistor 17.

Next, a sputtering film forming method using the thus configured sputtering film forming apparatus will be described with reference to the flowchart of FIG.
First, in step S1, preparation for film formation is performed. Specifically, the vacuum in the film forming chamber 7 of the vacuum chamber 1 is broken, and a target 10 made of, for example, ITO (a composite oxide film forming material mainly composed of indium-tin) is placed on the target holder 2 in the film forming chamber 7. It is attached.

  Next, the substrate 12 is placed on the substrate holder 3, and the mask 11 is placed in close contact with the film formation surface of the substrate 12. Thereafter, a bias electrode 16 connected to the pulse bias power source 6 is brought into contact with the surface of the mask 11.

  In step S2, preparation for starting film formation is performed. Specifically, when the attachment of the target 10 and the substrate 12 is completed, the vacuum chamber 1 is closed. Then, an exhaust valve (not shown) provided on the exhaust port 9 side of the vacuum chamber 1 is gradually opened, and the air in the film forming chamber 7 is exhausted by the vacuum pump. At this time, the gas introduction valve (not shown) provided on the gas introduction port 8 side is closed. The shutter 4 is also closed.

  When the degree of vacuum in the film forming chamber 7 reaches a predetermined value, the gas introduction valve is opened, and Ar gas adjusted to a constant flow rate by, for example, a mass flow controller is introduced. Subsequently, the exhaust amount of the exhaust pump is adjusted by adjusting the exhaust valve, and the total gas pressure in the film forming chamber 7 is adjusted to a predetermined value.

  In step S3, the transparent conductive film 21 is formed. Specifically, when the gas pressure in the film forming chamber 7 reaches a predetermined value, the high-frequency power source 5 is activated, and a predetermined high-frequency (RF) voltage as shown in FIG. Is done. This high frequency power is adjusted by a high frequency matching device and a power output.

  When a predetermined high frequency power is applied to the target 10, the Ar gas in the film forming chamber 7 is ionized and plasma is generated between the target 10 and the shutter 4. Then, when pre-sputtering is performed for a certain time and the impurities on the surface of the target 10 are removed, the shutter 4 is opened and sputtering film formation on the substrate 12 is started.

Hereinafter, the sputtering film formation of the present invention will be described in detail.
When an RF voltage as shown in FIG. 3A is applied to the target holder 2, the cathode voltage has a sine waveform biased to the negative side as shown in FIG. Then, as shown by hatching in the figure, sputtering of the target is performed during a period in which the cathode voltage is negative, and film formation is performed on the substrate 12. From the start of sputtering until the passage of a certain period (seasoning period shown in FIG. 5C), the transparent conductive film having a sufficient thickness to which a bias voltage can be applied from the pulse bias power source 6 is applied to the surface of the mask 11. Since the film 21 is not deposited, no bias voltage is applied to the surface of the mask 11 even when the pulse bias power supply 6 is activated. Therefore, in the present embodiment, the pulse bias power source 6 is set to 0 V during the seasoning period.

  In the seasoning period, as shown in FIG. 4A, the ionized Ar gas cation 18 is attracted to the target 10 side when the cathode voltage is negative. The sputtered particles 19 are blown off by collision. The sputtered particles 19 thus blown off fly toward the substrate 12 and adhere to the surface of the substrate 12 through the opening pattern 20 of the mask 11 as shown in FIG. Is done. At the same time, the sputtered particles 19 adhere to the surface of the mask 11 and the transparent conductive film 21 is deposited. Thus, as shown in FIG. 3B, film formation is performed in the target sputtering period in which the cathode voltage is negative.

  When the seasoning period elapses, the pulse bias power supply 6 is activated as shown in FIG. Then, during the period when the cathode voltage is positive and sputtering is stopped (target sputtering stop period shown in FIG. 5B), the pulse bias power supply 6 outputs a negative voltage and is deposited on the surface of the mask 11. A pulsed bias voltage (−Vb) is applied to 21. As a result, as shown in FIG. 5, the ionized Ar gas cation 18 is attracted to the mask 11 side and hits the transparent conductive film 21 deposited on the surface of the mask 11 as shown by the arrow in FIG. Bombardment is performed (mask cleaning).

  Next, as shown in FIG. 3B, when the positive period of the cathode voltage is finished and switched to negative, as shown in FIG. 3C, the pulse bias power source 6 is controlled in synchronization with the cathode voltage, The voltage applied to the mask 11 is set to 0 V (the pulse bias power supply 6 is turned off). As a result, as shown in FIG. 6A, normal sputtering film formation using the mask 11 is started again, and the transparent conductive film 21 is deposited on the surface of the substrate 12 and the mask 11 as shown in FIG. 6B. To do.

  Thereafter, the sputtering film formation and the mask 11 cleaning are performed alternately. When a predetermined time has elapsed, the shutter 4 is closed and the film formation is completed. Further, the high frequency power supply 5 and the pulse bias power supply 6 are turned off.

  Subsequently, in step S4, the substrate is taken out. Specifically, the exhaust valve and the gas introduction valve are closed, a leak valve (not shown) is opened, and the vacuum in the film forming chamber 7 of the vacuum chamber 1 is broken. Thereby, the film formation chamber 7 can be opened and the substrate 12 can be taken out.

FIG. 7 is a front view showing a schematic configuration of the second embodiment of the sputtering film-forming apparatus according to the present invention. Here, a different part from 1st Embodiment is demonstrated.
In the second embodiment, a DC power supply 22 is provided instead of the high frequency power supply 5 in the first embodiment, and the negative electrode side of the DC power supply 22 is connected to the target holder 2 (cathode electrode) via a resistor 23. In this DC sputtering apparatus, the positive electrode side is connected to the substrate holder 3 (anode electrode). In this case, the target material used is limited to a conductive material.

  In addition, the pulse bias power source 6 in the second embodiment outputs a negative pulse voltage having a constant cycle in a state where the cathode voltage (−Vc) is applied to the target holder 2, and outputs the cathode voltage ( A bias voltage (-Vb) having a voltage absolute value larger than -Vc) can be applied (Vc <Vb).

  According to the second embodiment, as shown in FIG. 8A, a negative DC voltage (cathode voltage) of several hundred volts is constantly applied to the cathode electrode during film formation, and the target 10 and the substrate 12 During this time, plasma is generated to form a film on the substrate 12.

  More specifically, as in the first embodiment, the target 10 is struck by argon cations 18 generated by the Ar gas being turned into plasma, and the sputtered particles 19 bounced thereby are deposited on the substrate 12. A conductive film is formed.

  Further, as shown in FIG. 8B, the pulse bias power source 6 sets the applied voltage to the mask 11 to 0 V during the seasoning period after the start of film formation, and a pulse-like negative voltage with a constant cycle after the seasoning period has elapsed. And a bias voltage (-Vb) having a voltage absolute value larger than the cathode voltage (-Vc) is applied to the mask 11 (Vc <Vb). Thus, when a pulsed bias voltage (-Vb) is applied to the mask 11, the argon cations 18 are attracted to the mask 11 side and deposited on the surface of the mask 11 as in the first embodiment. Ion bombardment is performed by hitting the conductive film (mask cleaning).

  Thus, according to the sputtering film forming apparatus of the present invention, by applying a pulsed negative voltage to the mask 11 in the film forming process performed by applying a high cathode voltage to the cathode electrode, The thin film deposited on the surface can be removed by hitting with an inert gas cation 18. Accordingly, the mask 11 can be cleaned while the film is formed, and the throughput of the film formation substrate can be improved.

  In the above embodiment, the case where the pulse bias power source 6 is stopped and the applied voltage to the mask 11 is set to 0 V in the seasoning period has been described. However, the present invention is not limited to this, and the high frequency power source 5 or the DC power source is used. The pulse bias power supply 6 may be activated at the same time as the activation of the voltage 22 so that a negative voltage having a constant period is applied to the mask 11. However, the bias voltage is not applied to the conductive film even when the pulse bias power supply 6 is activated until a conductive film having a sufficient thickness is deposited on the entire surface of the mask 11 and the bias voltage can be applied. The mask cleaning function is not demonstrated.

  In the above embodiment, the case where the film formed on the substrate 12 is a conductive film has been described. However, the mask 11 is a conductive metal mask or a composite mask in which a metal mask and a resin film are in close contact. In this case, the film to be formed may be a non-conductive film.

  Furthermore, although the batch-type sputtering film forming apparatus has been described in the above embodiment, the present invention is not limited to this, and may be an in-line type sputtering film forming apparatus. In this case, a load lock chamber is provided on the upstream side in the transport direction of the substrate 12 with the film forming chamber 7 therebetween, and an unload chamber is provided on the downstream side. First, the substrate 12 is transferred to the load lock chamber by opening the gate valve on the upstream side of the load lock chamber. After exhausting the load lock chamber, the gate valve on the downstream side of the load lock chamber is opened to form the substrate 12. The film is transferred into the film chamber 7 and placed in the substrate holder 3. Thereafter, the mask 11 previously held in the mask holder in the film forming chamber 7 is loaded and placed on the substrate 12, and the bias electrode 16 is brought into contact with the surface of the mask 11. Thereby, the RF sputtering film formation described above can be performed. On the other hand, when the film formation is completed, the bias electrode 16 is retracted, and then the mask 11 is unloaded. Then, after the film formation chamber 7 is evacuated, the gate valve on the downstream side of the film formation chamber 7 is opened to transfer the substrate 12 to the unload chamber. Thereafter, the gate valve on the downstream side of the film formation chamber 7 is closed, and the substrate 12 can be taken out by breaking the vacuum in the unload chamber.

2 ... Target holder 3 ... Substrate holder 5 ... High frequency power supply 6 ... Pulse bias power supply 10 ... Target 11 ... Mask 12 ... Substrate 22 ... DC power supply

Claims (11)

A sputtering film forming apparatus for generating a plasma between a target and a substrate by applying a high voltage cathode voltage to the cathode electrode, and forming a film on the substrate through a mask,
A sputtering film forming apparatus comprising a pulse bias power source capable of applying a pulsed negative voltage to the mask during a film forming process on the substrate. The cathode voltage is a high frequency voltage,
2. The pulse bias power source is driven in synchronization with the cathode voltage, and when the cathode voltage is positive, outputs the pulsed negative voltage to apply a negative voltage to the mask. Sputter deposition system. The cathode voltage is a DC voltage,
The pulse bias power source outputs the pulse-shaped negative voltage having a constant period in a state where the cathode voltage is applied, and applies a negative voltage having an absolute value larger than the cathode voltage to the mask. The sputtering film forming apparatus according to claim 1. The thin film formed on the substrate is a conductive film,
The mask is made of a non-conductive material.
The sputtering film-forming apparatus of any one of Claims 1-3 characterized by the above-mentioned.   The sputtering film forming apparatus according to claim 1, wherein the mask is made of a conductive material. A sputtering film forming method in which a high voltage cathode voltage is applied to a cathode electrode to generate plasma between a target and a substrate, and a film is formed on the substrate through a mask,
A sputtering film forming method, wherein a pulsed negative voltage is applied to the mask in the film forming process on the substrate.   The sputtering film forming method according to claim 6, wherein the cathode voltage is a high-frequency voltage, and the negative pulse voltage is applied to the mask when the cathode voltage is positive.   The cathode voltage is a direct current voltage, and the pulse-like negative voltage having a constant period whose absolute value is larger than the cathode voltage is applied to the mask in a state where the cathode voltage is applied. The sputtering film forming method according to claim 6.   9. The application of the pulse-like negative voltage to the mask starts after a predetermined time has elapsed since the start of film formation. Sputtering film forming method. The thin film formed on the substrate is a conductive film,
The mask is made of a non-conductive material.
The sputtering film-forming method according to any one of claims 6 to 9, wherein   10. The sputtering film forming method according to claim 6, wherein the mask is made of a conductive material. 11.