JP3094050B2 - Magnetron sputtering device and sputtering gun - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputtering apparatus and a sputtering gun for depositing a thin film on a semiconductor wafer, for example.

[0002]

2. Description of the Related Art In a magnetron sputtering apparatus, a substrate (for example, a semiconductor wafer) on which a thin film is to be formed and a sputtering gun are provided in a vacuum chamber, and the sputtering gun is opposed to the substrate. It has a target and a sputtering electrode provided.

At the time of sputtering, the inside of a vacuum chamber is maintained at a sputtering gas atmosphere (generally, argon gas is used) on the order of mTorr, and the sputtering target is generally provided through a sputtering electrode having a cooling mechanism in a sputtering target. Is applied with a negative voltage from a DC power supply. On the other hand, members such as an anode and a shield that are in contact with the sputtering target and the sputtering electrode via a gap of several mm are generally maintained at the ground potential together with the vacuum chamber. A magnetic circuit is provided close to the back surface of the sputtering target, whereby a parallel magnetic field is applied to the front surface of the sputtering target. Therefore, an orthogonal electromagnetic field is formed on the surface portion of the sputtering target, whereby cyclones are generated in the electrons in the plasma, and stable sputtering can be performed at a relatively low pressure.

As a target of a conventional sputtering gun, a target having a flat plate type or an inverted conical sputtering surface having a gentle slope and a diameter larger than that of a wafer is generally used. .

In recent years, as the degree of integration of an IC increases, the diameter of a via hole or a contact hole decreases to, for example, 0.5 μm, but the thickness of each layer does not change so much, so that the aspect ratio of the via hole or the contact hole increases. It is becoming something. When a thin film is formed on such a high-density wafer, the following problems occur when a conventional flat target is used.

That is, as shown in FIG. 10, in a sputtering apparatus using a target 2 in the form of a flat plate, the sputtered particles hit from the surface of the target 2 are approximately circled in each part of the target 2. As shown in (1), there are components in various directions.

A highly integrated ULSI 1 of 4M-DRAM or more used as a substrate has a contact hole (or via hole) 5 having a diameter of 0.5 μm and a depth of 1 μm (that is, an aspect ratio of 2). When the conductive film 4 is formed on the ULSI 1 by sputtering, not only sputtered particles from the vertical direction but also sputtered particles from all angles are incident on the contact hole 5. The deposition of the sputtered particles increases, blocking the entrance of the contact hole 5, and as a result, a conductive film having a sufficient thickness cannot be formed on the inner surface of the contact hole 5. Particularly, in the case of a contact hole or a via hole of 0.5 μm or less, in a conventional flat plate type sputtering gun, the step coverage (hereinafter, referred to as “step coverage”), particularly the deposition amount on the bottom of the hole (hereinafter, referred to as “bottom coverage”). It is pointed out that it is reduced to 10% or less.

[0008] In the conventional magnetron sputtering apparatus, the plasma is generated at a sputtering gas pressure of 1 mTorr.
If the pressure is not higher than r, the process space is not stabilized, and the pressure in the entire processing space must be increased to a stable level. Therefore, the sputtering efficiency of the conventional magnetron sputtering apparatus is not sufficient.

On the other hand, in the field of semiconductors, TiN and TiN
A compound film such as an O film is formed by reactive sputtering. Reactive sputtering generally uses an inert gas such as an argon gas and nitrogen or a mixed gas of nitrogen and oxygen as a reaction gas, and reacts the sputtered particles with the reaction gas to form a film.

However, in the reactive sputtering using such a reactive gas, a new problem as described below occurs. That is, when sputtering is performed using a reaction gas such as nitrogen gas, the sputtering efficiency is reduced to about 1/5 as compared with the case of using an inert gas (argon gas) alone. Further, the film deposited between the electrodes is easily peeled off, causing abnormal discharge.

The present invention has been made in view of the above circumstances, and it is possible to deposit a sufficient amount of sputter particles in a hole of a highly integrated wafer, and to reduce the sputter gas pressure in the entire sputtering processing space. An object of the present invention is to provide a magnetron sputtering apparatus and a sputtering gun that can perform sputtering while maintaining a low level and can perform reactive sputtering with higher efficiency.

[0012]

According to the present invention, there is provided a vacuum vessel, an object to be processed disposed in the vacuum vessel, and a sputtering apparatus disposed inside the vacuum vessel for injecting sputtered particles. The sputtering gun has a concave target, the tip of the recess is a cylinder, the bottom is a funnel or the tip of the recess is conical, and the bottom is a hemisphere or the bottom of the recess is cut. A conical or quadrangular pyramid, a sputtering gas supply means for supplying a sputtering gas into the concave target from the bottom of the concave target, and applying a power to the concave target to generate plasma with the sputtering gas. An electric field forming means for forming an electric field in the concave target, and an electric field forming means orthogonal to the electric field formed in the concave target. Provides a magnetron sputtering device, characterized in that it and a magnetic field forming means for forming a magnetic field including a that component. Secondly, a vacuum vessel, a sputtering gun disposed inside the vacuum vessel, for injecting sputter particles, and a support for supporting an object to be formed with a thin film in the vacuum vessel, A reaction gas supply means for supplying a reaction gas into the vacuum vessel, wherein the sputtering gun has a concave target, the tip of the concave is a cylinder and the bottom is a funnel or the tip of the concave is a cone. Sputtering gas supply means for supplying a sputtering gas into the concave target from the bottom of the concave target, the bottom being a hemisphere or a cone or a quadrangular pyramid obtained by cutting the bottom of the concave portion,
Electric field forming means for generating a plasma with the sputtering gas by applying power to the concave target, and forming an electric field in the concave target, with respect to the electric field formed in the concave target Magnetic field forming means for forming a magnetic field including orthogonal components, wherein the reaction gas is supplied to a region separated from the concave target and reacts with sputter particles generated by the plasma from within the concave target. And depositing a reaction product on the object to be processed.

[0013] Thirdly, the present invention provides a conical or quadrangular pyramid-shaped concave portion in which the tip of the concave portion is cylindrical and the bottom is funnel-shaped or the tip of the concave portion is conical and the bottom is hemispherical or the bottom of the concave portion is cut off. A target, a sputtering gas supply means for supplying a sputtering gas from the bottom of the concave target into the concave target, and applying a power to the concave target to generate plasma with the sputtering gas; An electric field forming means for forming an electric field in the target, and a magnetic field forming means for forming a magnetic field including a component orthogonal to the electric field formed in the concave target. provide. Fourthly, a conical or quadrangular pyramid-shaped target in which the tip of the recess is a cylinder and the bottom is a funnel or the tip of the recess is conical and the bottom is a hemisphere or the bottom of the recess is cut off, A sputtering gas supply means for supplying a sputtering gas from the bottom of the target into the concave target; and applying power to the concave target to generate plasma with the sputtering gas and form an electric field in the concave target. Electric field forming means, and magnetic field forming means for forming a magnetic field including a component orthogonal to the electric field formed in the concave target, and the concave shape is formed by the plasma at a position isolated from the plasma. A reaction gas supply means for supplying a reaction gas to the sputtered particles struck out of the target; Providing a sputtering gun, characterized in that to emit the sputtered particles generated by the plasma from.

[0014]

According to the present invention, the target of the sputtering gun is provided with a concave portion, and a plasma is formed therein to eject sputtered particles. Therefore, sputtered particles are ejected with extremely high directivity. Therefore, a sufficient amount of sputtered particles can be deposited even in the holes of a highly integrated wafer. Further, when supplying gas to the concave portion, a pressure gradient of the sputtering gas can be formed from the base end side to the distal end side of the concave portion, so that sputtering can be performed even when the processing space in the vacuum chamber is maintained at a low pressure. Can be. Therefore, the chance that the sputtered particles collide with the gas in the processing space where the sputtered particles move can be reduced, and the sputtering efficiency is extremely high. Further, the reactive gas is supplied to the sputtered particles at a position separated from the concave portion where the plasma is generated, so that reactive sputtering can be performed with high efficiency.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a magnetron sputtering apparatus according to one embodiment of the present invention. The magnetron sputtering apparatus includes a vacuum chamber 10 in which a film forming process is performed, an assembly 12 of a magnetron sputtering gun 30, and a sputtering gas supply source for supplying a sputtering gas (eg, argon gas) to the sputtering gun 30. And a support 1 for supporting a semiconductor wafer W as an object to be processed
And a reaction gas supply means for supplying a reaction gas (for example, nitrogen gas) into the vacuum chamber 10.

An exhaust port 10 is provided on a side wall of the vacuum chamber 10.
a is formed, and a vacuum pump 11 is connected to the exhaust port 10a. Then, the inside of the chamber 10 is kept at a desired degree of vacuum by evacuating the inside of the chamber 10 by the vacuum pump 11.

The support 14 is provided at the bottom of the vacuum chamber 10 and has a heating function. This support 1
The assembly 12 is disposed above the upper part 4. The sputtering gun 30 incorporated in the assembly 12 includes a target 31 having a concave portion 32. The target 31 is sputtered by the plasma of the sputtering gas supplied from the gas supply source 18 described above. As a result, sputter particles are ejected toward the wafer W. The detailed structure of the sputtering gun 30 will be described later.

A shutter 17 is provided between the assembly 12 and the wafer W on the support 14.
Pre-sputtering is performed with the shutter 7 closed, and the actual sputtering process is performed with the shutter 17 opened.

A reaction gas supply pipe 15 is connected to a side wall of the vacuum chamber 10 opposite to the exhaust port 10a, and the above-described reaction gas supply source 16 is connected to the supply pipe 15. Then, a reaction gas such as a nitrogen gas is supplied into the chamber 10 from the reaction gas supply source 16 via the reaction gas supply pipe 15.

The sputtering gun 30 constituting the assembly 12 is configured as shown in FIG. 2, for example. That is, the sputtering gun 30 includes the target 31 and the anode 3
4, a target clamp assembly 35, a target cooling block 36, an insulating material 37, a magnet 38, and a yoke 39.

The target 31 is formed of a film-forming material, for example, aluminum, copper, titanium, titanium nitride, etc., and has a concave portion 32 opened on the surface facing the wafer W. The concave portion 32 has an inverted tapered shape whose diameter increases toward the opening end. A gas supply hole 40 is formed at the bottom of the concave portion 32, and the gas supply source 18 is provided.
, A sputtering gas (plasma gas) such as an argon gas is supplied to the concave portion 32 through the gas supply hole 40.

The magnet 38 is disposed above the target 31, that is, on the rear surface of the target 31. A pole piece 41 made of a magnetic material is provided on the target 31 side of the magnet 38 so as to define a gas flow path. I have. The yoke 39 is provided so as to define the outside of the sputtering gun 30, and the yoke 39 forms a magnetic closed circuit between the target 31 and the magnet 38 and between the anode 34 and the magnet 38. As a result, target 31
The lines of magnetic force M are formed between the anode 34 and the magnet 38 provided on the opening side of. That is, a magnetic field is formed in the recess 32.

The anode 34 is made of, for example, aluminum and has an opening equal to or larger than the opening of the target 31. And it also has a role as a shield ring for shielding sputtered particles.

The target cooling block 36 is connected to the refrigerant passage 4
2 and has a substantially cylindrical shape, and the target 31 is fitted in a space inside the cylindrical shape. At the opening end side, the gap between the target 31 and the target clamp assembly 35 is fixed. The anode 34 is
Yoke 39 and cutout 43 provided on itself
The target clamp assembly 35 is fixed to itself and the target cooling block 36 by inserting a pin 44 into the
The pin 44 is inserted and fixed in the notch 43 provided at the bottom. The target and the anode are electrically insulated by an insulating material 37.

The refrigerant passage 4 of the target cooling block 36
The refrigerant is supplied to 2 through the refrigerant supply / drain pipes 42a and 42b, whereby the target 31 is cooled. In addition,
A cooling ring 46 is provided outside the yoke 39, and a cooling water supply / drain pipe 47a, 4
The refrigerant is supplied via the nozzle 7b, whereby the yoke 39 is also cooled.

The target 31 is connected to a DC power supply 45, for example, from -300 to -800 V
Is applied. The anode 34 is grounded. Therefore, between the anode 34 and the target 31,
That is, an electric field is formed in the concave portion 32, and a component perpendicular to the electric field among the magnetic fields formed therein forms an orthogonal electromagnetic field.

In the magnetron sputtering apparatus configured as described above, first, a semiconductor wafer W as an object to be processed is placed on the support 14 and the inside of the vacuum chamber 10 is, for example, 10 ⁻⁹ Torr by the vacuum pump 11. Evacuate the table. Then, sputtering is performed in a state where relative movement is caused between the sputtering gun 30 and the semiconductor wafer W as the object to be processed by the moving mechanism 20.

At the time of sputtering, a sputtering gas such as an Ar gas, ie, a plasma generating gas, is supplied from the gas supply source 18 to the recess 32 of the target 31 of the sputtering gun 30 through the gas introduction hole 40, and a pressure of 0.05 to 10 mTorr is applied. And a voltage of −300 to −800 V is applied between the target 31 and the anode 34. As a result, a plasma of the sputtering gas is generated in the recess 32.

The electrons 48 in the plasma region 33 perform cyclonic motion due to the orthogonal electromagnetic field formed by the magnetic field lines M and the electric field applied to the target, and the probability of collision with neutral argon particles is increased, and ionization is promoted. The ionized sputtering gas collides with the wall of the target 31 by the electric field. Thereby, the sputtered particles S are beaten out of the target 31. The sputtered sputtered particles S are ejected from the opening of the target.
The sputtered particles hitting the wall of the target again deposit on the target. However, the sputtered particles thus deposited are again sputtered by argon ions and ejected downward from the opening of the target, and as a result, a flow of sputtered particles S with high directivity is obtained.

In this case, the diameter of the gas introduction hole 40 of the target 31 is small, and the diameter increases toward the opening end of the concave portion 32. A pressure gradient is formed, and plasma is stably generated even when the processing space 60 has a low pressure. For example, in the plasma generation region 33, a pressure at which plasma can be generated stably, for example, on the order of 1 mTorr,
In the processing space 60, a pressure capable of reducing the chance of the sputtered particles colliding with the gas can be set to a pressure, for example, on the order of 0.1 mTorr. Further, it is possible to generate plasma even when the pressure in the concave portion 32 is 0.1 mTorr order, which is one order lower than the conventional pressure, for example, 0.2 mTorr. In this case, the pressure in the processing space 60 can be further reduced.

As described above, the sputtering processing space 60
In a state where the pressure is low, sputtering can be performed with sputtered particles having high directivity. Therefore, even when a sputtering process is performed on a wafer in which a contact hole is formed, a thin film can be formed with high step coverage and bottom coverage with high efficiency.

When performing reactive sputtering, a reaction gas, for example, nitrogen gas is introduced from the reaction gas supply source 16 into the processing space 60 of the vacuum chamber 10 via the reaction gas supply pipe 15. Since the sputtered particles S from the sputtering gun 30 pass through the processing space 60 toward the wafer W, the reaction gas is supplied toward the sputtered particles. The reaction gas supplied toward the sputtered particles reacts with the sputtered particles, whereby a reaction product is generated, and the reaction product is deposited on the wafer W. For example, when the sputtered particles are titanium and the reaction gas is nitrogen gas, TiN is formed on the wafer W. In this case, the reactive gas is supplied to a region separated from the concave portion 32 where the plasma of the sputtering gas is formed, so that highly efficient reactive sputtering is achieved.

The directivity of the sputtered particles can be adjusted by changing the length of the anode 34 provided on the tip side of the target 31. That is, the anode 34 also functions as a shield ring. For example,
When it is desired to further enhance the directivity of the sputtered particles, the anode 34 is made longer.

When such a sputtering process is repeated, the target 31 is gradually consumed due to generation of sputter particles, and the sputter portion 49 becomes larger as shown by a broken line 49a. However, in this case, only the size of the concave portion 32 changes, and the above-described function does not decrease.

The target 31 is made slightly smaller than the size of the space so as to be easily fitted into the space of the target cooling block 36. That is, there is a clearance between the outer peripheral surface of the target 31 and the inner peripheral surface of the cooling device such that the target 31 can be easily detached and attached to the inner peripheral surface of the target cooling block 36 due to thermal expansion of the target 31. It is configured like this. Therefore, when replacing the exhausted target, the temperature of the target is low and the size of the target cooling block 36 is reduced. Therefore, there is a gap between the target 31 and the target cooling block 36, and the target 31 can be removed from the target cooling block 36 very easily. New targets can be attached. Then, when a voltage is applied to the target electrode, plasma is generated, and the heat generated at that time causes the target 31 and the target cooling block 36 to expand, and both are securely fixed. Therefore, since the heat of the target 31 is transmitted to the target cooling block 36, the target 31 can be cooled without providing cooling means on the target 31 itself.
Can be cooled. Therefore, the target 31 can have a simple structure in which only the gas supply holes 40 are provided. Further, the cooling water supply / drain pipe to the target cooling block 36 does not need to be attached / detached once it is fixed, and the cooling water supply / drain mechanism can be simplified.

Various shapes can be adopted as the shape of the concave portion 32 of the target 31. For example, the structures shown in FIGS. 3A to 3C can be adopted.
In (a), the tip of the recess 32 is cylindrical and the bottom is funnel-shaped, and a gas supply hole 40 is formed in the center of the bottom. In (b), the tip of the concave portion 32 is conical and the bottom is hemispherical, and the gas supply hole 40 is opened at the center of the bottom similarly to the example of (a). In (c),
The bottom of the recess 32 has a conical shape (may be a quadrangular pyramid), and the gas supply hole 40 is also formed at the center of the bottom. Next, a case where an assembly having a plurality of sputtering guns is used will be described.

When the object to be processed becomes larger than an 8-inch wafer, a plurality of sputtering guns are required to form a thin film in all the regions of the object in a short time. FIG. 4 shows the device configuration in this case. The apparatus shown in FIG. 4 is different from the apparatus shown in FIG. 1 in that an assembly 12a having a plurality of sputtering guns 30 is provided instead of the assembly 12, and a moving mechanism 20 for moving the support 14 is provided. However, the other points are substantially the same.

The moving mechanism 20 is provided below the support 14, and is connected to the support 14 by a drive shaft 14a. The moving mechanism 20 includes a first moving unit 21 for vertically moving (Z direction) and rotating (θ direction) the support 14.
And a second moving unit 22 for horizontally moving.

The first moving unit 21 converts, for example, the rotation of the motor into a linear driving force by a ball screw mechanism or the like, moves the mounting table 14 connected to the driving shaft 14a up and down, and The support 14 can be rotated.

The second moving section 22 includes an X table 23, an X table
A table rail 24, a Y table 25, a Y table rail 26, and a base 27 are provided. X table 23
Is movable along the rail 24 in the X direction together with the first drive unit 21. Also, the Y table 25 is
It is movable in the Y direction (a direction orthogonal to the X direction) together with the first moving unit 21 and the X table 23 on the Y table rail 26 provided thereon.

As described above, the first moving unit 21
Since the X table 23 and the Y table 25 can move independently of each other, the mounting table 14 connected to the drive shaft 14a can move independently in the X, Y, Z, and θ directions.

Since the moving mechanism 20 is provided outside the vacuum chamber 10, it is possible to prevent heat and dust generated from the driving mechanism from adversely affecting the vacuum state in the vacuum chamber 10.

The bottom of the support 14 and the vacuum chamber 10
A bellows 28 is provided between the bottom and the bottom. The bellows 28 expands and contracts when the support 14 moves in the Z direction, and deforms in a direction inclined with respect to the vertical axis when moving in the X and Y directions. Therefore, even if the support 14 moves along the X, Y, and Z directions by the moving mechanism 50, the vacuum state in the vacuum chamber can be maintained.

The assembly 12a is composed of, for example, seven sputtering guns 30, and their targets are arranged as shown in FIG. In FIG. 5, seven targets 31 are arranged at the center A of the sputter gun assembly 12a and at each vertex of a regular hexagon having the center A as the center of gravity. According to this arrangement, the sputtering guns 30 can be arranged in the closest density. Therefore, using the sputtering gun 30 having a certain size, the sputtering gun assembly 1
2a can be minimized, which is advantageous in terms of space efficiency. However, the arrangement of the sputtering guns 30 is not limited to this arrangement, and can be appropriately determined according to various conditions such as the size of the wafer W and the size of the opening of the sputtering gun 30. Thus, a plurality of sputtering guns 3
0 is provided, the moving mechanism 20 is provided.
The reason why is necessary is described below.

The target 31 of the sputtering gun 30
Is formed with a concave portion 32, as described above,
Sputtered particles S are emitted with high directivity. Therefore, a large number of sputtered particles S that fly from a substantially vertical direction are provided for film formation in a hole located at a position facing the range of the diameter of the target 31. However, when the wafer W is fixed, the amount of sputtered particles directed to the wafer position facing the intermediate position between two adjacent targets 31 decreases. Also, the vertical component of the sputtered particles is reduced. That is, when the wafer W is fixed, the amount of sputter particles deposited on the surface of the wafer W and the incident angle vary. Therefore, in order to avoid such inconvenience, relative movement is caused between the sputtering gun 30 and the wafer W by the moving mechanism 20. An example of such a relative movement will be described with reference to FIGS.

As an example, the wafer W is raster-scanned in the X and Y directions parallel to the main surface of the wafer W shown in FIG. In this case, the raster scan is performed, for example, as shown in FIG. Raster scan along. Thus, a sufficient amount of sputter particles can be uniformly deposited on the wafer W under substantially the same conditions.

Next, a case where the wafer W is moved in the Z direction in FIG. 6 will be described. In this case, when the sputter gun assembly 12 is moved closer to the wafer W, the prospective angle with respect to the target 18 viewed from the contact hole increases, and more sputter particles are deposited on the shoulder of the contact hole. Conversely, when the sputter gun assembly 12 is moved away, the expected angle is reduced, and more sputter particles are deposited in the contact holes. Therefore, Z
The shape of the film can be controlled by moving the wafer W in the direction.

In this case, the range of movement in the Z direction is
For example, it is 100 mm to 250 mm, and within this range, it is possible to move in the Z direction without changing the volume of the vacuum chamber 10.

The movement in the X, Y, and Z directions can be independently performed as described above, and may be performed in only one direction, if necessary, or a combination of these movement directions. By combining these, a film with higher uniformity can be formed.

In addition to the movement in the X, Y, and Z directions, the wafer W may be rotated around the center of the wafer W as a rotation axis. This rotational movement makes it possible to improve the uniformity of film formation on the circumference connecting the center of the target 18. The rotational movement of the wafer W is represented by X,
The movement may be performed in combination with any one or more of the movements in the Y and Z axis directions, or only the rotational movement may be performed alone.

Further, an eccentric rotational movement about an eccentric axis offset from the center of the wafer W may be performed.
As described above, when the rotational movement is performed with the center of the wafer W as the rotation axis, the distance from the center of the target located in the periphery is different from each other in order to improve the uniformity of film formation in the radial direction. It needs to be. In such a case, it is difficult to arrange the targets 31 in the sputter gun assembly in a close-packed structure, and the structure of the apparatus must be complicated. However, by performing the eccentric rotational movement in this manner, the uniformity of film formation in the radial direction as well as in the circumferential direction can be maintained without complicating the device structure while keeping the arrangement of the targets 31 in the close-packed structure shown in FIG. Can be improved. In this case as well, the rotational movement of the wafer W may be performed in combination with any one or more of the movements in the X, Y, and Z directions, or only the rotational movement may be performed alone.

Further, the position of the center axis of the assembly 12a and the position of the center axis of the wafer W may be shifted, and both may be rotated. By causing such a rotational movement, it is possible to improve the uniformity of film formation on a wide two-dimensional plane. When the above rotational movement is performed, a magnetic seal, an O-ring, or another hermetic seal that allows rotation can be used as the hermetic seal.

Incidentally, the relative movement between the sputtering gun and the wafer W is not limited to the above-described embodiment, but may be X, Y,
Various combinations of the Z direction, the circular motion, the eccentric motion, and the orbital motion can be performed. Such relative movement may be performed intermittently using a step motor,
It may be a continuous movement.

Next, a modification of the sputtering gun will be described. The sputtering gun used in the present invention is not limited to the one shown in FIG.
The structure shown in FIG.

FIG. 7 shows a case where a plurality of magnets are used without using a yoke, and FIG. 8 shows a case where an electromagnet is used as a magnetic field forming means. 7 and 8, those substantially the same as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

In the sputtering gun shown in FIG. 7, a columnar magnet 61 is arranged above the target 31, that is, on the back side, and an annular magnet 62 is arranged on the tip side of the target 31. A pole piece 63 made of a magnetic material is connected to the target 31 side of the magnet 61 so as to define a gas flow path. The tip portion 63a of the pole piece 63 is formed with a screw, and is fixed to the body of the pole piece with a screw, and only the tip portion 63a is replaceable. Magnet 61
The magnetic field lines are formed on the magnet 62 via the pole piece 63 from the magnet, and as a result, similar to the sputtering gun of FIG.
A magnetic field is formed in the recess 32. The target cooling block 36 is provided with a spiral refrigerant passage 68 a, and the refrigerant is supplied through the refrigerant supply / drain pipe 68. A cooling ring 6 for the pole piece is provided around the pole piece 63.
The cooling ring 66 is provided with a refrigerant passage 67 a through which a refrigerant is supplied through a refrigerant supply / distribution pipe 67. Further, an anode cooling ring 69 is provided around the anode 34, in which the refrigerant passage 6 is provided.
9a are formed. The outer periphery of the sputtering gun is bent by a stainless steel member 71, and the stainless steel member 71 and the target cooling block 36
Are insulated by an insulating member 72. Reference numeral 65 is a cavity spacer interposed between the target 31 and the cooling block 36, 64 is an insulating member, and 70 is a clamp member.

The sputtering gun of FIG. 8 has basically the same structure as that of FIG. 3 except that the permanent magnet 38 of FIG. By using the electromagnet 80 in this manner, the current can be changed according to the consumption of the target, and the magnitude of the magnetic field can be changed.

Next, another embodiment of the present invention will be described. In the above embodiment, the reaction gas such as nitrogen is introduced from the chamber 10 into the processing space 60. However, an example in which the reaction gas supply means is provided in the sputtering gun itself will be described.

FIG. 9 is a sectional view showing a sputtering gun provided with a reaction gas supply means. The basic configuration of the sputtering gun of FIG. 9 is the same as that of FIG. 7, and the same components as those of FIG. 7 are denoted by the same reference numerals. In FIG.
Is a reaction gas supply source for supplying a reaction gas such as nitrogen gas. The reaction gas from the reaction gas supply source 93 is
The gas is introduced into the hollow portion of the anode 34 through a reaction gas supply hole 94 formed in the sputtering gun.

On the other hand, an argon gas as a sputtering gas is supplied to the recess 32 through the gas supply introduction hole 40. In this case, since the argon gas passes through the plasma region, the ionization efficiency is high and the sputtering efficiency is high. Sputtered particles struck out by the plasma generated in the concave portion 32 fly from the concave portion 32 to the processing space 60 through the hollow portion of the anode 34. Then, a reactive gas is supplied to the sputtered particles in the hollow portion of the anode 34, and these are supplied from the concave portion 32 to the anode 34.
A reaction product particle is formed by the action of electrons toward the substrate and the like, and the reaction product particle is deposited on the wafer, thereby realizing reactive sputtering. For example, if the sputtered particles reactive gas Ti is N ₂ can be deposited TiN. Also in this embodiment, the reaction gas is formed in the recess 32 where the plasma of the sputtering gas is formed.
Since it is supplied to a region remote from the, high-efficiency reactive sputtering is achieved.

Another advantage of this embodiment is that the reaction gas is introduced from the gap between the target and the anode, so that it is possible to prevent sputter particles from flowing between the electrodes. Further, since the pressure in the processing space 60 is low, scattering of sputter particles due to the introduced gas is eliminated, and the wraparound is reduced, so that the shield plate around the processing space can be made small.

Further, the conductance of the sputtering gas can be increased, and the exhaust capacity can be increased by one digit without increasing the size of the exhaust device.
The background pressure is improved by two orders of magnitude due to a synergistic effect with the reduction of the discharge pressure, which greatly contributes to the improvement of the film quality.

Although the example in which the reactive gas supply means is basically provided in the sputtering gun of FIG. 7 is shown here, the same reactive gas supply means can be provided in the sputtering guns of FIGS. 2 and 8. Needless to say.

The film formation rate when sputtering is performed only with nitrogen gas is about 1/5 of that when sputtering is performed only with argon gas. However, as described above, nitrogen gas is applied to the region where sputtered particles fly. When supplied, the film formation rate is three times or more as compared with sputtering using only nitrogen gas.

Further, from the viewpoint of film quality, it is preferable to apply a negative DC bias or a negative AC bias, or both of them to the object to be processed, as is performed in normal sputtering. Thereby, the formed film becomes dense and the film quality is further improved. The film to be formed is TiN
In this case, the resistance of the film can be reduced.

The present invention can be variously modified without being limited to the above embodiment. For example, although the above-described embodiment has been described with respect to an example in which a semiconductor wafer is used as an object to be processed,
The present invention is not limited to this, and can be applied to, for example, LCD substrates, magnetic disks, magnetic tapes, and the like. Also,
Although the support is moved by the moving mechanism, it is sufficient that relative movement between the object to be processed and the sputtering gun occurs, and the sputtering gun may be moved.

[0068]

According to the present invention, a sufficient amount of sputter particles can be deposited even in a hole of a highly integrated wafer, and sputtering is performed while maintaining a low sputter gas pressure in the entire sputtering processing space. A magnetron sputtering apparatus and a sputtering gun capable of performing reactive sputtering with higher efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnetron sputtering apparatus according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating one embodiment of a sputtering gun used in the apparatus of FIG.

FIG. 3 is a cross-sectional view illustrating an example of the shape of a target.

FIG. 4 is a sectional view showing a magnetron sputtering apparatus according to another embodiment of the present invention.

FIG. 5 is a view schematically showing an arrangement of targets in the assembly of the apparatus shown in FIG. 4;

FIG. 6 is a schematic diagram illustrating relative movement between a wafer and a sputtering gun in the apparatus of FIG.

FIG. 7 is a view showing another example of a sputtering gun used in the magnetron sputtering apparatus of the present invention.

FIG. 8 is a view showing still another example of a sputtering gun used in the magnetron sputtering apparatus of the present invention.

FIG. 9 is a sectional view showing a sputtering gun according to one embodiment of the present invention.

FIG. 10 is a diagram showing a state in which a thin film is formed in a contact hole by using a conventional flat-plate sputtering gun.

[Explanation of symbols]

10: vacuum chamber, 12, 12a: assembly, 1
4 ... Support, 15 ... Reaction gas supply pipe, 16,93
... Reaction gas supply source, 18 ... Sputtering gas supply source, 30 ... Sputtering gun, 31 ... Target, 32 ... Concave part, 34 ... Anode, 38 ...
Magnet, 39: yoke, 40: sputtering gas supply hole, 45: power supply, 94: reaction gas supply hole,
S: Sputtered particles W: Wafer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 H01L 21/203 H01L 21/31

Claims (13)

(57) [Claims] 1. A vacuum vessel, an object to be processed arranged in the vacuum vessel, and a sputtering gun arranged inside the vacuum vessel to eject sputtered particles, wherein the sputtering gun comprises: Having a concave target,
The tip of the recess is cylindrical and the bottom is funnel-shaped, or the tip of the recess is conical and the bottom is hemispherical or conical or truncated pyramid with the bottom of the recess cut off. A sputtering gas supply unit for supplying the inside of the concave target, a power generation means for applying power to the concave target to generate plasma with the sputtering gas, and forming an electric field in the concave target, Magnetic field forming means for forming a magnetic field including a component orthogonal to the electric field formed in the concave target. 2. A vacuum vessel, a sputtering gun disposed inside the vacuum vessel for injecting sputter particles, and a support for supporting an object to be formed with a thin film in the vacuum vessel. And a reaction gas supply unit for supplying a reaction gas into the vacuum vessel, wherein the sputtering gun has a concave target,
The tip of the recess is cylindrical and the bottom is funnel-shaped, or the tip of the recess is conical and the bottom is hemispherical or conical or truncated pyramid with the bottom of the recess cut off. A sputtering gas supply unit for supplying the inside of the concave target, a power generation means for applying power to the concave target to generate plasma with the sputtering gas, and forming an electric field in the concave target, Magnetic field forming means for forming a magnetic field including a component orthogonal to the electric field formed in the concave target, wherein the reaction gas is supplied to a region isolated from the concave target, and Reacting with sputter particles generated by the plasma from within the target and depositing a reaction product on the object to be processed. That magnetron sputtering apparatus. 3. A conical or quadrangular pyramid-shaped target in which the tip of the recess is a cylinder and the bottom is a funnel or the tip of the recess is conical and the bottom is a hemisphere or a truncated bottom of the recess. Gas supply means for supplying a sputtering gas into the concave target from the bottom of the concave target, and applying a power to the concave target to generate plasma with the sputtering gas, thereby forming an electric field in the concave target. And a magnetic field forming means for forming a magnetic field including a component orthogonal to the electric field formed in the concave target. 4. A conical or quadrangular pyramid-shaped target in which the tip of the recess is a cylinder and the bottom is a funnel or the tip of the recess is conical and the bottom is a hemisphere or the bottom of the recess is cut off, Gas supply means for supplying a sputtering gas into the concave target from the bottom of the concave target, and applying a power to the concave target to generate plasma with the sputtering gas, thereby forming an electric field in the concave target. And a magnetic field forming means for forming a magnetic field including a component orthogonal to the electric field formed in the concave target, the concave portion being formed by the plasma at a position separated from the plasma. A reactive gas supply means for supplying a reactive gas to sputtered particles struck out of the concave target; Sputtering gun, characterized in that from Tsu in preparative emit the sputtered particles generated by the plasma. 5. The magnetron sputtering apparatus according to claim 1, further comprising means for introducing a negative DC bias to the object. 6. The magnetron sputtering apparatus according to claim 1, further comprising means for introducing a negative AC bias to the object to be processed. 7. The magnetron sputtering apparatus according to claim 1, further comprising means for introducing a negative DC and AC bias to the object to be processed. 8. The sputtering gun according to claim 3, wherein a pressure gradient is formed in the concave portion from the base end side to the distal end side of the concave target. 9. The sputtering gun according to claim 3, wherein an anode is provided on the opening side of the concave target, and an annular magnet is provided on the anode. 10. The directivity is improved by installing an anode on the opening side of the concave target and making the hollow portion of the anode longer.
The described sputtering gun. 11. The magnetron sputtering apparatus according to claim 1, wherein the support installed in the vacuum vessel and on which the object to be processed is installed has a moving mechanism. 12. The apparatus according to claim 1, wherein the sputtering gun is relatively movable between the object and the object to be processed.
Or the magnetron sputtering apparatus according to 2. 13. The magnetron sputtering apparatus according to claim 1, wherein a plurality of said sputtering guns are provided in an assembly.