JP2023061729A - Sputtering film deposition apparatus and sputtering film deposition method - Google Patents

Abstract

To efficiently sputter a target.SOLUTION: A sputtering film deposition apparatus includes: a treatment vessel including a mounting table for mounting a substrate; a metal window facing the mounting table, having a first surface constituting the ceiling surface of the treatment vessel and consisting of non-magnetic metal; an inductive coupling antenna arranged to be separated from a second surface of the metal window on the side opposite to the first surface of the metal window and for forming plasma in the treatment vessel; a RF power supply connected to the inductive coupling antenna; one of a DC power supply, DC pulse power supply or AC power supply connected to the metal window; and a gas supply part for supplying raw gas for forming the plasma in the treatment vessel.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a sputtering deposition apparatus and a sputtering deposition method.

For example, the magnetron sputtering deposition apparatus of Patent Document 1 forms a high-density plasma by a DC electric field due to a DC voltage applied to the target material and a magnetic field from the magnet on the back of the target material, thereby sputtering the target material. Then, a film is formed.

For example, the sputtering film forming apparatus of Patent Document 2 uses inductively coupled plasma to sputter a target material to form a film. This sputtering deposition apparatus has an induction coil provided corresponding to the dielectric plate, and has a magnet on the back surface of the target material. An induced electric field is formed in the processing space via.

International Publication No. 2009/116430 JP 2012-209483 A

The present disclosure provides techniques that can efficiently sputter a target material.

According to one aspect of the present disclosure, a processing container having a mounting table on which a substrate is mounted, and a first surface facing the mounting table and constituting a ceiling surface of the processing container, are made of a non-magnetic metal. an inductively coupled antenna spaced apart from a second surface of the metallic window opposite the first surface of the metallic window for generating plasma within the processing vessel; a high-frequency power source connected to the metal window; a DC power source, a DC pulse power source, or an AC power source connected to the metal window; A sputter deposition apparatus is provided.

According to one aspect, the target material can be efficiently sputtered.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the sputtering film-forming apparatus which concerns on embodiment. FIG. 4 is a diagram for explaining generation of inductively coupled plasma using a metal window; The figure which planarly viewed the metal window and inductive coupling antenna which concern on embodiment. The figure which planarly viewed the metal window and inductive coupling antenna which concern on embodiment. The figure which showed an example of the vertically-wound rectangular coil antenna which concerns on embodiment. FIG. 5 is a diagram showing experimental results of source power dependence in sputtering film formation according to the embodiment; FIG. 4 is a diagram for explaining sputtering of a target material according to the embodiment; FIG. 5 is a diagram showing experimental results of DC voltage dependence and plasma electron density in sputtering film formation according to the embodiment; FIG. 4 is a diagram for explaining a parallel magnetic field and sputtering by the sputtering film forming apparatus according to the embodiment; 4 is a flowchart showing a sputtering film formation process according to the embodiment;

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant description may be omitted.

[Sputter deposition equipment]
First, a sputter deposition apparatus 10 according to one embodiment will be described. FIG. 1 is a cross-sectional view showing a sputtering film forming apparatus 10 according to an embodiment. The sputtering film forming apparatus 10 shown in FIG. 1 uses plasma to form an aluminum oxide (AlO) film, an oxide semiconductor (IGZO), or the like on a rectangular substrate, for example, a glass substrate for FPD (hereinafter referred to as substrate G). can be used when Examples of FPDs include liquid crystal displays (LCDs), electroluminescence (EL) displays, plasma display panels (PDPs), and the like. However, the substrate is not limited to the FPD glass substrate.

The sputter film deposition apparatus 10 has an airtight prismatic body container 1 made of a conductive material, for example, aluminum with an anodized inner wall surface. The main container 1 is assembled so as to be disassembled, and is electrically grounded by a ground wire 1a.

The main container 1 is vertically partitioned into an antenna chamber 3 and a processing container 4 by a rectangular metal window 2 which is insulated from the main container 1 . The metal window 2 constitutes the top wall of the processing vessel 4 . The metal window 2 is composed, for example, of a non-magnetic, electrically conductive metal, such as aluminum or an alloy containing aluminum.

Between the side wall 3 a of the antenna chamber 3 and the side wall 4 a of the processing container 4 , a support shelf 5 projecting inside the main container 1 is provided. The support shelf 5 is made of an electrically conductive material, preferably a metal such as aluminum.

The metal window 2 is composed of a plurality of split windows 2a to 2d that are electrically insulated from each other via an insulating member 7. As shown in FIG. The split windows 2a to 2d are supported by the support shelf 5 via the insulating member 7. As shown in FIG. It has a structure in which the metal window 2 is suspended from the ceiling of the main container 1 by a plurality of suspenders (not shown). It should be noted that FIG. 1 schematically shows the divided form of the metal window 2 and does not show the actual divided form. Various division forms of the metal window 2 will be described later.

The support shelf 5 is formed with a plurality of gas supply holes 21a. The gas supply unit 20 is connected to a plurality of gas supply holes 21a through gas supply pipes 21. As shown in FIG. The gas supply unit 20 supplies a processing gas including source gas for plasma generation. A processing gas is introduced into the processing chamber 4 through a plurality of gas supply holes 21 a through a gas supply pipe 21 . A gas space (not shown) may be provided inside the metal window 2 and connected to the gas supply pipe 21 to supply gas.

In the antenna chamber 3 above the metal window 2, there is provided an antenna unit 40 facing the metal window 2 and having an inductively coupled antenna 13 arranged to form a circular ring. As will be described later, the inductive coupling antenna 13 is made of a conductive material such as copper, and is spaced apart from the metal window 2 by a spacer (not shown) made of an insulating member.

A first high-frequency power supply 18 is connected to the inductively coupled antenna 13 of the antenna unit 40 via a feeder line 16 and a matching device 17 . During plasma processing (sputtering film formation processing), the inductively coupled antenna 13 is supplied with, for example, 13.56 MHz high-frequency power (hereinafter also referred to as source power) via a feeder line 16 extending from a first high-frequency power supply 18 . ) is supplied. A loop current is induced in the divided windows 2a to 2d of the metal window 2 by the induced electric field formed by the inductive coupling antenna 13. FIG. As a result, an induced electric field is formed in the processing container 4 via loop currents induced in the divided windows 2a to 2d of the metal window 2. FIG. This induced electric field converts the processing gas supplied from the gas supply hole 21a into plasma in the plasma generation space S immediately below the metal window 2 in the processing container 4, generating inductively coupled plasma.

The metal window 2 has a first side and a second side. The lower surface 22a of the metal window 2 is defined as a first surface, and the upper surface 22b of the metal window 2, which is the opposite surface to the first surface, is defined as a second surface. The first surface constitutes the ceiling surface of the processing container 4 . An inductively coupled antenna 13 is arranged on the second surface side away from the metal window 2 to generate plasma in the processing container 4 . A target material T is fixed to the lower surface 22a of the metal window 2 while maintaining electrical continuity with the metal window 2 by joining with indium brazing or screwing. Since the target material T is a consumable item, it is replaced when the thickness reaches a certain threshold value or less, and a new target material T is bonded to the lower surface 22a of the metal window 2 by brazing or fixed by screwing. The target material T is made of a material suitable for the film to be deposited. When forming an AlO film and an AlN film, the target material T may be made of aluminum. When depositing the SiO ₂ film and the SiN film, the target material T may be made of silicon. When forming an IGZO film, the target material T may be composed of indium (In), gallium (Ga), zinc (Zn), and oxygen (O).

A mounting table 23 facing the first surface is fixed to the bottom of the processing container 4 via an insulating member 24 . The mounting table 23 is made of a conductive material such as aluminum whose surface is anodized, and the substrate G is mounted on the mounting surface of the mounting table 23 . The mounted substrate G is attracted and held by an electrostatic chuck (not shown) provided on the mounting surface.

An insulating shield ring 25 a is provided on the upper peripheral edge of the mounting table 23 , and an insulating ring 25 b is provided on the peripheral surface of the mounting table 23 . A lifter pin 26 used when loading and unloading the substrate G is inserted through the mounting table 23 through the bottom wall of the main container 1 and the insulating member 24 . The lifter pins 26 are driven up and down by an elevating mechanism (not shown) provided outside the main container 1 to transfer the substrate G when the substrate G is carried in and out.

Furthermore, in order to control the temperature of the substrate G, the mounting table 23 is provided with a temperature control mechanism including a heating means such as a heater, a coolant flow path, etc., and a temperature sensor (neither is shown). . Piping and wiring for these mechanisms and members are led out of the main container 1 through the opening 1 b provided in the bottom surface of the main container 1 and the insulating member 24 .

A side wall 4a of the processing container 4 is provided with a loading/unloading port 27a for loading/unloading the substrate G and a gate valve 27 for opening and closing the port. An exhaust system 30 including a vacuum pump and the like is connected to the bottom of the processing container 4 via an exhaust pipe 31 . The inside of the processing container 4 is evacuated by the exhaust device 30, and the inside of the processing container 4 is set and maintained at a predetermined vacuum atmosphere (for example, 10 mTorr (1.33 Pa)) during plasma processing.

A fine gap (not shown) functioning as a cooling space is formed on the rear surface side of the substrate G placed on the placing table 23, and is used to supply He gas as a heat transfer gas at a constant pressure. A He gas flow path 32 is provided. By supplying the heat transfer gas to the rear surface side of the substrate G in this way, it is possible to suppress the temperature rise and temperature change due to the sputtering film formation process of the substrate G under vacuum.

The sputtering film forming apparatus 10 further has a control section 100 . The control unit 100 is composed of a computer, and has a CPU for controlling each component of the plasma processing apparatus, an input device, an output device, a display device, and a storage device. The storage device has a storage medium storing parameters of various processes performed by the plasma processing apparatus and programs for controlling the processes performed by the sputtering deposition apparatus 10, that is, processing recipes. The CPU calls up a predetermined processing recipe stored in the storage medium, and causes the plasma processing apparatus to perform a predetermined processing operation based on the processing recipe.

[Metal window]
Next, the metal window 2 will be described in detail. DC pulse power sources 62a and 62b are connected to the metal window 2, and the DC pulse power sources 62a and 62b (also referred to collectively as the DC pulse power source 62) generate a rectangular wave (pulse wave) DC voltage (hereinafter referred to as , also referred to as a DC pulse voltage) is applied to the metal window 2 . The frequency of the DC pulse voltage may be 5 kHz to 150 kHz. The DC pulse voltage has two values forming a rectangular wave, and the two values are controlled to be 0 or a negative DC voltage. A DC power supply or an AC power supply may be connected to the metal window 2 instead of the DC pulse power supply 62 . If the metal window 2 is connected to a DC power supply, a negative DC voltage is applied to the metal window 2 . When an AC power supply is connected to the metal window 2 , the AC power supply applies an AC voltage with a predetermined frequency (eg, 50 kHz) to the metal window 2 . As described above, the metal window 2 is electrically connected to any one of a DC power source, a DC pulse power source, and an AC power source, and thus the metal window 2 is made of a conductive material. Also, the metal window 2 is made of a non-magnetic metal. A non-magnetic metal is, for example, aluminum. In the following description, increasing (increasing) the DC voltage (DC pulse voltage) applied to the metal window 2 means increasing (increasing) the absolute value of the DC voltage (DC pulse voltage).

A low-pass filter (LPF) 61 is provided between each of the metal window 2 and the DC pulse power sources 62a and 62b to prevent the high frequency power from the first high frequency power source 18 from propagating to the DC pulse power sources 62a and 62b. . With such a structure, the inductive coupling antenna 13 and the metal window 2 are used to generate a high-density plasma in the processing container 4, and a DC pulse voltage is applied to the metal window 2, so that the ions in the high-density plasma are directed to the metal window 2. It pulls in and enables reactive sputtering.

FIG. 2 is a diagram for explaining generation of inductively coupled plasma using the metal window 2. As shown in FIG. As shown in FIG. 2, an induced current is generated on the upper surface of the metal window 2 by the high frequency current _IRF flowing through the inductively coupled antenna 13 . The induced current flows only in the surface portion of the metal window 2 due to the skin effect, but the metal window 2 is insulated from the support shelf 5 and the main container 1 . Therefore, if the planar shape of the inductive coupling antenna 13 is linear, the induced current that flows on the upper surface of the metal window 2 flows to the side surface of the metal window 2, and then the induced current that flows to the side surface of the metal window 2 flows to the lower surface of the metal window 2 and returns to the upper surface of the metal window 2 again through the side surface of the metal window 2 to generate an eddy current _IED . Thus, an eddy current _IED is generated in the metal window 2 that loops from the upper surface to the lower surface. Among the looping eddy currents _IED , the current flowing through the lower surface of the metal window 2 generates an induced electric field _IP in the processing container 4, and the induced electric field _IP generates plasma of the processing gas.

On the other hand, when the inductive coupling antenna 13 is provided so as to circulate along the circumferential direction in the plane corresponding to the metal window 2, if a solid single plate is used as the metal window 2, the metal window 2 is Eddy currents do not flow on the bottom surface and no plasma is generated. In other words, the eddy current _IED generated on the upper surface of the metal window 2 by the _inductive coupling antenna 13 only loops on the upper surface of the metal window 2 and does not flow on the lower surface of the metal window 2 . Therefore, the metal window 2 is configured in various ways as described below so that an eddy current flows in the lower surface of the metal window 2 and a desired induced electric field is generated.

[Configuration of metal window]
In the first mode, the metal window 2 is divided into a plurality of divided regions and insulated from each other. This causes the eddy current _IED to flow to the bottom surface of the metal window 2 . That is, by dividing the metal window 2 into a plurality of parts insulated from each other, an induced current flows through the upper surface of the divided metal window 2 (divided window), reaches the side surface, flows from the side surface to the lower surface, and then flows through the side surface again. to generate a looped eddy current _IED that returns to the top surface. For this reason, the metal window 2 is divided into a plurality of divided windows. Several division examples of the metal window 2 and arrangement examples of the inductive coupling antenna 13 will be described below.

FIG. 3 is a plan view of the metal window 2 and the inductive coupling antenna 13 according to the embodiment. The metal window 2 has a rectangular shape having long sides and short sides corresponding to the substrate G. As shown in FIG. In FIG. 3A, the inductive coupling antenna 13 is provided with a plurality of antenna segments 131, 132, 133, each of which is an annular rectangular coil antenna, so as to face the metal window 2 and circulate. Each of the annular rectangular coil antennas constituting the plurality of antenna segments 131, 132, 133 may be formed into a frame shape by spirally winding one antenna wire (not shown). The antenna wires may be spirally wound symmetrically to form a frame. Thus, in this example, the rectangular metal window 2 is divided substantially radially toward each corner of the metal window 2 in order to uniformly form an induced electric field along the lower surface 22 a of the metal window 2 . Thereby, the metal window 2 is divided into four divided windows 2a to 2d. The four split windows 2a-2d are trapezoidal on the long sides and triangular on the short sides. These trapezoids and triangles are configured such that the height of the trapezoid whose base is the long side is the same as the height of the triangle whose base is the short side. The split windows 2a to 2d are insulated from each other via an insulating member 7. As shown in FIG.

As an example of the inductively coupled antenna 13, a plurality of antenna segments each including an annular rectangular coil antenna are arranged.

In FIG. 3B, as shown in FIG. 1, two DC pulse power supplies 62a and 62b are provided. A DC pulse power supply 62a is connected to the split windows 2a and 2b and supplies a DC pulse voltage to the split windows 2a and 2b. A DC pulse power supply 62b is connected to the split windows 2c and 2d and supplies a DC pulse voltage to the split windows 2c and 2d. Note that the illustration of the low-pass filter 61 is omitted in FIGS. 3(b) and 3(c).

In FIG. 3(c), a DC pulse power supply 62 is connected to the split windows 2a-2d and supplies a DC pulse voltage to the split windows 2a-2d. For example, when the outer plasma is weak, the duty of the DC voltage applied to the split windows 2c and 2d is larger than the duty of the DC voltage applied to the split windows 2a and 2b (that is, the two values of the pulse voltage are negative The uniformity of the in-plane distribution of the film can be achieved by lengthening the time during which the DC voltage is applied. Therefore, the in-plane distribution of attraction of ions in the plasma can be changed according to the area of the divided window. In this case, only one DC pulse power supply 62 is required, and the number of DC pulse power supplies can be reduced.

FIG. 4 is a plan view of the metal window 2 and the inductively coupled antenna 13 according to the embodiment, which is another example of FIG. In this example, the metal window 2 is divided into six rectangular divided windows 2e to 2j. The divided windows 2e to 2j are connected through a low-pass filter 61 to one of DC pulse power supplies 62c, 62d, and 62e. A DC pulse power supply 62c is connected to the split windows 2e and 2f and supplies a DC pulse voltage to the split windows 2e and 2f. A DC pulse power supply 62d is connected to the split windows 2g and 2h and supplies a DC pulse voltage to the split windows 2g and 2h. A DC pulse power supply 62e is connected to the split windows 2i and 2j and supplies a DC pulse voltage to the split windows 2i and 2j.

The inductively coupled antenna 13 may be composed only of parallel antennas as shown in FIG. The parallel antenna generates an induced electric field that contributes to plasma generation, and has a rectangular region formed to face the metal window 2 and face the substrate G, and these rectangular regions are linearly or grid-shaped. divided into plasma control regions. An antenna segment 134 forming part of the rectangular area is arranged in each of the divided areas, and a multi-divided parallel antenna is configured such that the antenna lines of the plurality of antenna segments 134 are all parallel.

As shown in FIG. 5, the antenna segment 134 of FIG. 4 has an antenna wire 135 made of a conductive material such as copper spirally wound in a direction intersecting the substrate G (metal window 2), for example, in a direction perpendicular to the substrate G (metal window 2), that is, in a vertical direction. It consists of a vertically wound rectangular coil antenna that is wound into a shape. High-frequency power is supplied from a first high-frequency power supply 18 to each vertically wound rectangular coil antenna.

In FIG. 4, five antenna segments 134 straddling two split windows 2e and 2f are arranged in the longitudinal direction of the split windows 2e and 2f. Similarly, five antenna segments 134 straddling two split windows 2g and 2h and five antenna segments 134 straddling two split windows 2i and 2j are arranged.

The vertically-wound rectangular coil antenna is not limited to the arrangement in which the antenna segments 134 are linearly arranged in the longitudinal direction of each split window shown in FIG. 4, and may be arranged in a grid pattern. For example, the antenna segment 134 is divided into a 4-split type with 2 vertical and horizontal segments, a 9-split type with 3 vertical and horizontal segments, a 25-divided type with 5 vertical and horizontal segments, or more, and a vertically wound rectangular coil antenna is installed in each segmented window. They may be arranged in a grid.

In this way, the antenna segments 134 made up of vertically-wound rectangular coil antennas are arranged in a straight line or in a lattice so that the directions of the induced electric fields (high-frequency currents) of the antenna segments 134 are all the same. As a result, there is no region where the induced electric fields cancel each other unlike the case where annular rectangular coil antennas are arranged side by side. For this reason, the efficiency is higher than when annular rectangular coil antennas are arranged, and the uniformity of plasma can be improved.

In the region of the metal window 2 corresponding to the inductive coupling antenna 13, the relationship between the division number of the metal window 2 and the division number (the number of antenna segments) of the inductive coupling antenna 13 is arbitrary. However, when using a bipolar DC pulse power supply as the DC pulse power supply, the number of divisions of the metal window must be an even number.

In the sputter deposition apparatus 10 described above, the metal window 2 mediates the induced electric field by the inductive coupling antenna 13 and functions to form plasma within the processing container 4 . In addition, the metal window 2 functions to draw ions into the target material T for performing the sputter deposition process on the substrate G. FIG.

With such a structure, high-density plasma is generated in the processing container 4 using the inductive coupling antenna 13 and the metal window 2, and by applying a DC pulse voltage to the metal window 2, ions are drawn in and reactive sputtering is performed by the high-density plasma. enable By depositing sputtered particles emitted from the target material T by sputtering on the substrate G, it is possible to form an AlO film, an AlN film, an SiO film, an SiN film, a TiN film, an IGZO film, and the like.

Plasma is formed by an electromagnetic field formed by supplying source power to the inductively coupled antenna 13 . The target is sputtered by applying a DC pulse voltage to the metal window 2 on which the target material T is attached to attract ions. Therefore, according to the sputter deposition apparatus 10 of the present disclosure, plasma formation and ion attraction can be controlled independently. The magnetic field formed by the inductive coupling antenna 13 and the DC electric field are used to increase the plasma density. There is an advantage that the target material is uniformly sputtered without significant plasma bias.

Note that the metal window 2 itself may be used as the target material. In addition, the DC voltage applied to the target material will be described with a DC pulse voltage as an example in the present disclosure, but it is not limited to this, and may be a continuous DC voltage or an AC voltage. The inductively coupled antenna 13 may have a structure in which a plurality of antenna segments each composed of a vertically wound rectangular coil antenna are arranged in a straight line or in a lattice. The inductively coupled antenna 13 may have a configuration in which a plurality of annular rectangular coil antennas are arranged concentrically, or a configuration in which a vertically wound rectangular coil antenna and an annular rectangular coil antenna are combined.

Four effects of the sputtering film forming apparatus 10 of the present disclosure will be described below in order. The four effects are high deposition rate by high-density plasma (effect 1), independent control of source power and DC voltage (effect 2), deposition of IGZO film with few defects (effect 3), and sputtering by parallel magnetic field. This is the effect (effect 4). The metal window 2 and the inductively coupled antenna 13 were evaluated based on the configuration shown in FIG.

[Effect 1: High deposition rate by high-density plasma]
By applying a DC pulse voltage to the metal window 2 to generate a DC electric field, a high film formation rate can be obtained by plasma densified by the alternating magnetic field and the DC electric field from the inductively coupled antenna 13 . An experiment was conducted using the sputtering apparatus 10 of FIG. 1 under the following process conditions.

<Process conditions>
Gap from metal window to mounting table 50mm
Processing container internal pressure 5 mT (0.67 Pa)
Gas Argon (Ar) gas, oxygen (O ₂ ) gas 50/50 sccm
Target material Aluminum DC pulse voltage -500 V 50 kHz Duty = 50%
Source power variable Under the above conditions, the target material was sputtered with plasma of a mixed gas of argon and oxygen to form a transparent AlO film, and the results are shown in FIG. FIG. 6 is a diagram showing experimental results of source power dependence in sputter deposition according to the embodiment.

The horizontal axis of FIG. 6 indicates the source power from the first high-frequency power supply 18, the vertical axis (left) indicates the deposition rate (DR) of the AlO film, and the vertical axis (right) indicates the refractive index (RI) of the AlO film. indicates According to this, by supplying source power to the inductively coupled antenna 13 and applying a DC pulse voltage to the metal window 2, the plasma can be densified and the deposition rate can be increased.

Further, when the source power was increased, higher density plasma could be generated, and the deposition rate (DR) and refractive index (RI) of the AlO film could be further improved. In addition, the ratios of the film thickness of the side portion to the film thickness of the bottom portion of the AlO film formed on the stepped portion on the substrate G are 1.00, 1.00, and 0 when the source power is 1000 W, 3000 W, and 5000 W, respectively. 0.95. In other words, regardless of the magnitude of the source power, the coverage of the AlO film was good. From the above, according to the sputtering film forming apparatus 10 of the present disclosure, it was found that the film forming rate and the refractive index can be improved, and a dense AlO film with good coverage can be formed by sputtering.

The reason why a film with good coverage can be formed by sputtering will be described with reference to FIG. FIG. 7 is a diagram for explaining sputtering of the target material T in the sputtering film forming apparatus 10 according to the embodiment. When a negative DC voltage is applied to the metal window 2, ions in plasma formed from argon gas or the like, for example, argon ions (Ar ⁺ ), are drawn into the metal window 2 and collide with the target material T, forming aluminum. Al ions (Al ⁺ ) are emitted as sputtered particles from the target material T thus formed.

In addition, the oxidation and nitridation of the film are promoted by the high-density plasma generated by supplying the source power, and a dense AlO film can be formed. In the source-powered inductively coupled antenna 13, a parallel magnetic field B is generated due to the shape of the antenna segments 131-134 shown in FIGS. As a result, Al ions (Al ⁺ ) are emitted at a high angle under the Lorentz force (F=qv×B). As a result, an AlO film with good coverage can be formed by sputtering.

[Effect 2: Independent control of source power and DC voltage]
In the sputter deposition apparatus 10, control for applying a DC pulse voltage to the metal window 2 and control for supplying a plasma source to the inductive coupling antenna 13 can be performed independently. Therefore, a film with few defects can be formed. An experiment was conducted using the sputtering apparatus 10 of FIG. 1 under the following process conditions.

<Process conditions>
Gap from metal window to mounting table 50mm
Processing container internal pressure 5 mT (0.67 Pa)
Gas Argon (Ar) gas, oxygen (O ₂ ) gas 50/50 sccm
Target material Aluminum Source power 3 kW
DC pulse voltage variable 50kHz Duty=50%
FIG. 8 shows the result of forming an AlO film by sputtering the target material T with plasma of a mixed gas of argon and oxygen under the above conditions. FIG. 8 is a diagram showing experimental results of DC voltage dependence and plasma electron density in sputter deposition according to the embodiment.

In FIG. 8A, the horizontal axis indicates the direct current pulse voltage (DC), the vertical axis (left) indicates the deposition rate (DR) of the AlO film, and the vertical axis (right) indicates the refractive index (RI) of the AlO film. show. According to this, when the DC pulse voltage applied to the metal window 2 is increased, the probability of ions in the plasma, for example, argon ions, colliding with the target material T is increased, and the sputtering force can be increased. DR) could be increased. On the other hand, even if the DC pulse voltage was increased, the refractive index (RI) could be maintained.

The horizontal axis of FIG. 8B indicates the source power, and the vertical axis indicates the plasma electron density (Ne density [pieces/cm ³ ]). According to this, when comparing line A when the DC pulse voltage is 0 V and line B when the DC pulse voltage is −300 V, the plasma electron density Ne was almost unaffected by the value of the DC pulse voltage. . In other words, it was found that the plasma electron density Ne depends on the source power and does not depend on the DC pulse voltage.

From the above, by independently performing the control of applying the DC pulse voltage to the metal window 2 and the control of applying the plasma source to the inductive coupling antenna 13, while generating high-density plasma, an insulating film with few defects, It was proved that an IGZO film can be formed.

[Effect 3: Film formation with few defects]
For example, if the DC voltage applied to the metal window 2 is increased, the ions in the plasma can be drawn into the target material T strongly. Therefore, the amount of sputtered particles emitted from the target material T can be increased, and the film formation rate can be increased. On the other hand, if the DC voltage applied to the metal window 2 is increased, the energy of the sputtered particles also increases and is strongly impacted into the film, which may cause defects in the film. The sputtering film deposition apparatus 10 of the present disclosure can independently control the DC voltage and the source power. Therefore, for example, in order to form an IGZO film with few defects, the DC voltage applied to the metal window 2 can be lowered and the source power can be raised to about 5000 W, for example. As a result, an IGZO film with few defects can be formed by controlling the DC voltage so as to weaken the attraction of ions in the plasma while increasing the film formation rate by generating high-density plasma.

[Effect 4: Sputtering Effect by Parallel Magnetic Field]
FIG. 9 is a diagram for explaining a parallel magnetic field and sputtering formed below the metal window 2 of the sputtering film deposition apparatus 10 according to the embodiment. FIG. 9(a) shows the parallel magnetic field B1 below the metal window 2 (target material T) during sputtering by the sputtering film deposition apparatus 10 according to the embodiment, and FIG. 9(b) shows the magnetron sputtering according to the reference example. A magnetic field B2 below the metal window 2 (target material T) during sputtering by the apparatus is shown.

In the magnetron sputtering deposition apparatus of the reference example shown in FIG. A target material T is sputtered by forming a density plasma to form a film. In the sputtering film formation, electrons in the plasma are enclosed by the magnetic field B2 to generate high-density plasma and increase the film formation rate (sputter rate). However, the magnetic field B2 between the N-pole and S-pole magnets 91 deviates the sputtering area of the target material T, and the target material T between the magnets 91 is scraped in an annular shape . This makes the consumption of the target material T between the magnets 91 higher than the consumption of the target material T under the magnets 91 . Due to non-uniform use of the target material T, the timing of replacement is advanced, and the utilization efficiency of the target material T is poor. In addition, reaction by-products and other substances tend to accumulate on the portion under the magnet 91 where the target material T cannot be scraped, which may become a source of particle generation.

In contrast, in the sputter deposition apparatus 10 of the present disclosure, a plurality of antenna segments of the inductively coupled antenna 13 are used so that the antenna line facing the metal window 2 forms a ring parallel to the metal window 2. or arranged so that all of the antenna lines facing the metal window 2 are parallel.

Therefore, as shown in FIG. 9(a), a parallel magnetic field B1 that is wide in the horizontal direction is formed under the target material T. As shown in FIG. Therefore, in the sputter deposition apparatus 10, there is no location where the magnetic field is locally strong as in the reference example shown in FIG. 9B. Therefore, the target material T is uniformly scraped by the direct current electric field E generated by the direct current voltage applied to the metal window 2 and the parallel magnetic field B1 widely formed below the target material T, thereby enabling uniform film formation. , a film with good coverage can be deposited. Since the target material T can be cut uniformly, the efficiency of utilization of the target material T is high, and the life of the target material T can be extended.

[Sputtering film formation method]
Finally, a sputter deposition method performed in the sputter deposition apparatus 10 of the present disclosure will be described with reference to FIG. 10 . FIG. 10 is a flow chart showing sputtering film formation processing according to the embodiment. The sputtering film forming process is controlled by the control unit 100 and executed by the sputtering film forming apparatus 10 .

When this process is started, the control unit 100 opens the gate valve 27, loads the substrate G from the loading/unloading port 27a, and places it on the mounting table 23 in step S1. Thus, the preparation of the substrate G is completed.

Next, in step S<b>3 , the control unit 100 supplies the processing gas from the gas supply unit 20 into the processing container 4 . Next, in step S<b>5 , the control unit 100 supplies high-frequency power from the first high-frequency power supply 18 to the inductively coupled antenna 13 to generate plasma within the processing container 4 .

Next, in step S7, the control section 100 applies a DC pulse voltage from the DC pulse power source 62 to the metal window 2 to draw ions into the metal window 2 side. Next, in step S9, the target material T is sputtered by ions, and sputtered particles emitted from the target material T are deposited on the substrate G. As shown in FIG. Thereby, a desired film such as an AlO film is formed on the substrate.

According to the sputtering film forming method described above, the sputtering film forming apparatus 10 of the present disclosure can be used to generate high-density plasma, and a desired film such as an AlO film can be formed by reactive sputtering. Further, by independently controlling the source power supplied from the first high-frequency power supply 18 to the inductively coupled antenna 13 and the DC pulse voltage applied from the DC pulse power supply 62 to the metal window 2, high mobility and high reliability can be achieved. A desired film such as an IGZO film having properties can be formed.

As described above, according to the sputtering film forming apparatus and the sputtering film forming method of the present embodiment, a high-density plasma is formed by a DC pulse voltage applied to the metal window, the target material T is efficiently sputtered, A film formation rate can be increased.

It should be considered that the sputter deposition apparatus and the sputter deposition method according to the embodiments disclosed this time are illustrative in all respects and not restrictive. Embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The items described in the above multiple embodiments can take other configurations within a consistent range, and can be combined within a consistent range.

10 Sputter deposition apparatus 1 Main container 2 Metal windows 2a, 2b, 2c, 2d Divided window 3 Antenna chamber 4 Processing container 13 Inductive coupling antenna 18 First high frequency power source 20 Gas supply unit 22a Lower surface 22b of metal window Upper surface of metal window 23 Mounting table 62 DC pulse power supply T Target material

Claims (9)

a processing container having a mounting table on which the substrate is mounted;
a metal window made of a non-magnetic metal and having a first surface that faces the mounting table and constitutes a ceiling surface of the processing container;
an inductively coupled antenna spaced apart from a second surface of the metal window opposite the first surface of the metal window for generating plasma within the processing vessel;
a high frequency power supply connected to the inductively coupled antenna;
either a DC power source, a DC pulse power source, or an AC power source connected to the metal window;
a gas supply unit that supplies a processing gas for generating the plasma into the processing container;
A sputtering deposition apparatus having a The metal window has a function of forming the plasma in the processing container by mediating an induced electric field by the inductive coupling antenna, and a function of a target material for performing a sputtering process on the substrate.
The sputtering film forming apparatus according to claim 1 . a processing container having a mounting table on which the substrate is mounted;
a metal window made of a non-magnetic metal and having a first surface that faces the mounting table and constitutes a ceiling surface of the processing container;
an inductively coupled antenna spaced apart from a second surface of the metal window opposite the first surface of the metal window for generating plasma within the processing vessel;
a target material provided on the first surface;
a high frequency power supply connected to the inductively coupled antenna;
either a DC power source, a DC pulse power source, or an AC power source connected to the metal window;
a gas supply unit that supplies a processing gas for generating the plasma into the processing container;
A sputtering deposition apparatus having a wherein the metal window is composed of a plurality of split windows that are electrically insulated from each other;
The sputtering film forming apparatus according to any one of claims 1 to 3. A plurality of antenna segments are arranged in the inductively coupled antenna,
The sputtering film forming apparatus according to any one of claims 1 to 4. The inductively coupled antenna has a plurality of the antenna segments, which are circular rectangular coil antennas, arranged concentrically.
The sputtering film forming apparatus according to claim 5 . In the inductively coupled antenna, a plurality of antenna segments, which are longitudinally wound rectangular coil antennas, are arranged in a lattice or in a straight line. are arranged parallel to each other,
The sputtering film forming apparatus according to claim 5 . The non-magnetic metal is aluminum,
The sputtering film forming apparatus according to any one of claims 1 to 7. A sputtering film forming method to be executed in the sputtering film forming apparatus according to any one of claims 1 to 8,
a step of placing the substrate on the mounting table;
supplying a processing gas from the gas supply unit into the processing vessel;
supplying high-frequency power from a high-frequency power source to an inductively coupled antenna to generate plasma in the processing container;
applying a DC voltage, a DC pulse voltage, or an AC voltage from either a DC power supply, a DC pulse power supply, or an AC power supply connected to a metal window to draw ions from the plasma into the metal window;
depositing sputtered particles sputtered by the ions onto the substrate;
A sputtering film formation method comprising:

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