JPH10204633A - Sputtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a film having stable film quality by preventing the generation of arcing by a simple constitution. SOLUTION: This sputtering device is generated with plasma by applying a potential difference to the space between a substrate 3 and a target 4 arranged oppositely each other to the positions with prescribed intervals in a vessel 2 fed with a prescribed reactive gas. In this case, the target 4 is divided into a primary region and a secondary region, and magnetic filed generating means 16 and 17 generating the magnetic fields on the surface of the primary region of the target, an insulating means 8 electrically insulating the primary region and secondary region 2 of the target, voltage applying means 9, 13 and 24 applying voltage to the primary region of the target and a primary voltage controlling means controlling voltage to be applied to the secondary region of the target independently of the primary region of the target are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order.

BACKGROUND OF THE INVENTION Problems to be Solved by the Invention Means for Solving the Problems Embodiments of the Invention (FIGS. 1 and 2) Effects of the Invention

[0003]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spatter device, and is suitably applied to, for example, a spatter device having a reflective film.

[0004]

2. Description of the Related Art Conventionally, a spatter device usually has
^In a vacuum chamber evacuated to an ultra-high vacuum of ^-8 [Torr], a target made of a disk-shaped metal lump (silicon lump) and a substrate to be processed are placed parallel to each other via a predetermined distance. Then, an inert gas of Ar is supplied into the vacuum chamber, and a potential difference of about 1000 [V] is applied between the target and the substrate using the target as a cathode and the substrate as an anode.

Thus, the sputter device generates plasma between the target and the substrate, and generates a leakage magnetic field by using a magnet provided below the target, thereby generating a leakage magnetic field of Ar atoms ionized in the vacuum chamber. pops the Si atom from the Tagetsuto surface collide with Tagetsuto parts it is, then O ₂ or N
By supplying a reaction gas such as _{2, a} SiO ₂ film or a SiN _x film is formed on the substrate surface.

[0006]

In this type of spatter device, one method of diagnosing the state of the generated plasma is a probe method, which uses a small hole formed in a housing portion of a vacuum chamber. A wire-like probe made of a conductor such as tungsten is inserted therein, and a DC voltage V is applied to the tip of the probe to increase the voltage value until the voltage becomes equal to the plasma potential. At this time, in the probe method, the electron temperature or the electron density is calculated based on the relationship between the DC voltage V applied to the probe and the probe current I flowing from the plasma to the tip of the probe, that is, the Langmuir characteristic (gradient of the graph), The state of the plasma is diagnosed based on the electron temperature or the electron density.

In the sputter device having such a configuration, when an insulator such as an oxide or a nitride due to a reaction gas adheres to the probe when the spatter is sputtered, the insulator takes a positive charge and is charged and charged.
At some point, dielectric breakdown occurs and arcing occurs. Therefore, in order to prevent the occurrence of such arcing, an insulator attached to the probe is removed.

In this case, a negative voltage is applied to the probe to lower the potential of the probe below the cathode voltage,
By attracting and colliding the positively charged Ar particles with the probe, the attached insulator and the Ar particles are repelled together by the impact of the collision.

However, in a sputter device, outgassing occurs when the insulator attached to the probe surface is repelled, and the probe itself is made of tungsten different from the target. In the meantime, there is a problem in that when the sheet is flipped off, it adheres to the target surface or the substrate surface in a spot-like manner, causing contamination contamination.

[0010] In addition, in the sputter device, even in the non-erosion area on the target, an insulator such as an oxide or a nitride adheres due to the reaction gas when the spatter is sputtered.
There is a problem that the insulator takes on a positive charge and is charged and charged, and at some point, dielectric breakdown occurs to cause arcing.

[0011] Furthermore, in the sputter device, various types of plasma analyzers, such as an energy analyzer for directly measuring the electron temperature of the plasma, and making a hole in the wall of the vacuum chamber and inserting a probe into the plasma in the plasma diagnosis by the probe method, and inserting a probe into the plasma. There was a problem that a sensor had to be provided, leading to an increase in cost.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a spatter apparatus which can prevent arcing from occurring and form a stable film with a simple structure.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a substrate and a target are disposed at positions separated by a predetermined distance in a vessel to which a predetermined reaction gas is supplied, so as to face each other. In a sputter device for generating a plasma by applying a potential difference, a target is divided into a first region and a second region, and a magnetic field generating means for generating a magnetic field on a surface of the first region of the target; Insulating means for electrically insulating the first area from the second area, voltage applying means for applying a voltage to the first area of the target, and the second area of the target independently of the first area of the target And first voltage control means for controlling the voltage applied to the first and second power supply units.

Thus, when the plasma is generated and sputtered, even if the insulator attached to the second region of the target has a positive charge and is charged, the first region of the target is charged.
By independently setting the potential of the second region of the target to a negative potential independently of the region of the target, particles having a positive charge are attracted and collided with the surface of the second region of the target. Thus, the insulator attached to the surface of the second region of the target can be removed.

In addition, by setting the potential of the second region of the target to a positive potential independently of the first region of the target, a positively charged insulator attached to the surface of the second region of the target can be obtained. Can be repelled and removed at the surface of the second region of the target.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a spatter device according to the embodiment as a whole, and a substrate 3 is mounted via a substrate holder 3A as an anode fixed to a housing portion of a vacuum chamber 2.
And a titanium target 4 as a cathode is fixed at a position facing the substrate 3.

Further, in the spatter device 1, by providing the mechanical pump 5 and the turbo molecular pump 6 outside the vacuum chamber 2, the inside of the vacuum chamber 2 can be evacuated and set to a predetermined sputter pressure.

The target 4 has a circular shape and is integrally fixed to a backing plate 7 of the same shape, so that the backing plate 7 does not come into contact with the housing of the vacuum chamber 2 via an insulating ring 8. Installed.

The target 4 and the backing plate 7 are divided into concentric circles having a radius of about half of the target 4, and the inner target 4A and the backing plate 7A and the outer target 4B and the backing plate 7B. Are electrically isolated from each other.

The target 4B on the outer peripheral side is electrically connected to the variable cathode power supply 9 via a backing plate 7B on the outer peripheral side, and is applied with a predetermined voltage during operation. In this case, an ammeter 10 is mounted between the backing plate 7B on the outer peripheral side and the variable cathode power supply 9, and the amount of current detected by the ammeter 10 is converted into digital data via an analog / digital converter 11. And sends it to the computer 12.

Computer 12 as voltage application means
Detects the voltage value applied to the outer backing plate 7B based on the amount of current detected by the ammeter 10, and controls the voltage value applied to the backing plate 7B via the variable cathode power supply 9. doing.

In practice, the spatter device 1 operates the outer target 4B and the substrate 3 by operating the outer target 4B as a cathode and the substrate holder 3A and the housing of the film forming chamber 2 as the anode during the spatter. A plasma is generated in between.

The spatter device 1 is connected to a computer 12.
By controlling the voltage value applied to the backing plate 7B via the variable cathode power supply 9, the electron temperature of the plasma generated between the target 4B and the substrate 3 is controlled.

The inner target 4A is electrically connected to a variable cathode power supply 13, and an ammeter 14 is mounted between the variable cathode power supply 13 and the target 4A to detect the amount of current flowing into the target 4A. Then, the data is transmitted to the computer 12 as digital data via the analog / digital converter 15.

The computer 12 serving as the first voltage control means controls the inner target 4 based on the detected current amount.
A voltage value applied to A is calculated, and the applied voltage is controlled via the variable cathode power supply 13.
Thus, the spatter device 1 is moved to the inner target 4A.
Is changed independently of the target 4B on the outer peripheral side.

On the other hand, in the backing plate 7B on the outer peripheral side, a plurality of block-shaped ferrite magnets are annularly attached along a position corresponding to a lower portion of the outer peripheral portion of the target 4B to form a magnet 16.

Further, a plurality of block-shaped ferrite magnets are annularly attached along a position corresponding to an inner peripheral portion separated from the magnet 16 by a predetermined distance to form a magnet 17. Here, the spatter device 1 is the target 4B
A shield plate 18 is attached so as to cover the outer peripheral portion of the backing plate 7B, and covers the magnet 16 so as not to be spattered.

As a result, a leakage magnetic field is generated on the surface of the target 4B on the outer peripheral side by the magnets 16 and 17, and Ar atoms in the plasma are attracted to the region of the surface of the target 4B where the leakage magnetic field is generated and collide. And reacts with the reaction gas to form a film on the surface of the substrate 3.
An erosion region is formed on the surface of the target 4B.

Further, the target 4A on the inner peripheral side is attached with a rod-shaped probe 19 made of titanium of the same material as that of the target 4 protruding from the center portion,
The linear motor shaft 20, the probe moving motor 21 as the driving means, and the position detecting unit 21A as the detecting means are integrally attached to the probe 19 from the surface of the target 4A through the backing plate 7A on the inner peripheral side. The probe 19 can be moved in the axial direction from the surface of the target 4A to a position near the substrate holder 3A while detecting the amount of protrusion.

Here, the probe moving motor 21 is connected to the power supply, and also connected to the computer 12 via the pulse generator 22 and the driver 23.
Under the control of the computer 12, the amount of protrusion of the probe 19 from the surface of the target 4A can be finely adjusted based on the pulse output from the pulse generator 22.

In this case, the spatter device 1 is
When plasma is generated when the tip of the probe 19 is located near the center of the plasma, arcing may occur with reference to a needle-like projection (not shown) provided at the tip of the probe 19. In order to avoid this, the probe 19 can be finely moved and adjusted.

The probe 19 is electrically connected to a variable cathode power supply 24 so that the potential can be changed from a negative potential to a positive potential. An ammeter 25 is attached between the variable cathode power supply 24 and the probe 19.

Thus, the ammeter 25 detects the amount of current flowing from the plasma to the tip of the probe 19, converts it into digital data by the analog / digital converter 15, and sends it to the computer 12. Here, in the probe method, the voltage value applied to the tip portion of the probe 19 is gradually increased by the computer 12 as the second voltage control means until it becomes substantially equal to the plasma potential. The amount of current flowing into the front end portion is detected.

The computer 12 calculates an electron temperature and an electron density based on a Langmuir characteristic curve obtained from a voltage value V applied to the probe 19 and a probe current I flowing into the probe 19, and varies based on the electron temperature. The voltage applied through the cathode power supply 9 is adjusted to generate plasma with an optimum electron temperature.

In the spatter device 1, the computer 12 as a control means calculates a resistance value R when an optimum film quality can be obtained in the reactive sputter based on the Langmuir characteristic curve, and keeps the resistance value R constant. The opening / closing amount of the reaction gas piezo valve 27 is adjusted via the gas control driver 26 so as to control the supply amount of the reaction gas such as O ₂ gas and N ₂ gas via the gas supply pipe 28. I have.

Thus, the sputter device 1 can form a stable film having a composition such as TiO _X or TiN _{X on the} surface of the substrate 3. The gas control driver 26 adjusts the opening / closing amount of the inert gas piezo valve 29 based on an instruction from the computer 12 when initially supplying the inert gas of Ar. Is supplied in a predetermined amount.

The sputter device 1 is provided at a predetermined position in the vacuum chamber 2 with a neutralizer 3 as an electron emitting means.
1 is arranged so that electrons can be emitted to the surface of the target 4A on the inner peripheral side via the power supply 32 for the neutralizer based on an instruction from the computer 12.

Thus, a positively charged insulator such as an oxide or a nitride attached to the inner surface of the target 4A is neutralized with electrons emitted from the neutralizer 31 and removed. It has been done.

Next, FIG. 2 shows the internal sectional structure of the target 4 on the cathode side in detail. The target 4 and the backing plate 7 are concentrically divided at a position of about half of the radius, and the inner and outer backing plates 7A and 4A and the outer backing are interposed via a plurality of O-rings 40 to 42. The plate 7B and the target 4B are electrically separated with a predetermined gap so that they do not contact each other.

In this case, the inner peripheral side backing plate 7
A and a hole 43 having a predetermined diameter are provided at the center of the target 4A.
They are electrically separated through a predetermined gap so as not to contact the backing plate 7A and the target 4A via the holes 4 and 45, and are arranged so as to be movable in the axial direction.

Here, the inner peripheral side backing plate 7A
And the target 4A and the backing plate 7B on the outer peripheral side
And an O-ring 40 provided between the target and the target 4B.
The O-rings 44 and 45 provided between the probe 19 and the backing plate 7A and the target 4A on the inner peripheral side and the probe 19 are electrically separated through a predetermined gap, and the vacuum state in the vacuum chamber 2 is maintained. It is used as a sealing material to keep

The probe 19 is electrically connected to a variable cathode power supply 24 so that the applied voltage can be adjusted by the computer 12.

The probe 19 has a predetermined diameter and has a needle-like projection 19A at the center of the tip of the probe.
Is provided to reduce the surface area of the projection 19A to prevent the adhesion of the insulator. As a result, in the probe 19, the insulator does not adhere to the protrusion 19A, and the current always flows from the plasma into the protrusion 19A.

In the backing plate 7B on the outer peripheral side, the magnet 16 fixed in an annular shape along the outer peripheral portion and the magnet 17 fixed in an annular shape inside the magnet 16 form a target 4B. In this case, a leakage magnetic field is generated by the magnets 16 and 17, and an erosion region is formed during the sputtering.

In this case, the inner peripheral side backing plate 7
A and target 4A are the backing plate 7 on the outer peripheral side.
B and the target 4B are electrically isolated from each other, and are not affected by the leakage magnetic field due to the magnets 16 and 17, and become a non-erosion region.

The backing plate 7B on the outer peripheral side is electrically connected to the variable cathode power supply 9 and operates as a cathode. Further, the inner backing plate 7A is electrically connected to a variable cathode power supply 13 so that the applied voltage can be adjusted by the computer 12.

Thus, the inner backing plate 7A and the target 4A can be changed in potential independently of the outer backing plate 7B and the target 4B. Cooling water is supplied to the outer peripheral side backing plate 7B via a water passage 46, and the outer peripheral side target 4B in which the erosion region is formed is cooled via the backing plate 7B.

In the above configuration, the spatter device 1 changes the potential of the inner target 4A, the outer target 4B, and the probe 19 independently, and changes the material of the probe 19 to the inner target 4A.
And the target 4B on the outer peripheral side is made of titanium of the same material.

Therefore, when the sputter device 1 generates a plasma and sputters, the insulator such as an oxide or a nitride attached to the surface of the target 4A on the inner peripheral side, which is a non-erosion region, takes a positive charge. Even if it is charged, the potential of the inner backing plate 7A and the potential of the target 4A are changed from negative potential to positive potential through the variable cathode power supply 13 under the control of the computer 12, so that the oxide adhered to the surface of the target 4A. Insulators such as silicon and nitride can be removed.

In practice, when the potential of the inner backing plate 7A and the potential of the target 4A are reduced to a negative potential, the sputter device 1 attracts particles having positive charges and collide with each other. Thus, insulators such as oxides and nitrides attached to the surface of the target 4A can be removed together with particles having a positive charge.

In this case, however, since the spatter device 1 lowers the potential of the target 4A to a negative potential, all the positively charged insulators are not necessarily repelled by the impact of the collision and remain attached. It may remain. In such a case, the spatter device 1 emits electrons to the inner peripheral side surface of the target 4A by the neutralizer 31 so that the remaining positively charged insulators such as oxides and nitrides. Can be removed by neutralizing with an electron.

Further, the spatter device 1 raises the potential of the inner backing plate 7A and the target 4A to a positive potential near the ground, so that a positively charged insulator such as an oxide or a nitride is charged. Target 4
On the surface A, the positive members can repel each other and be removed.

Further, in the spatter device 1, since the outer target 4B, the inner target 4A, and the probe 19 are electrically separated from each other, the potentials of the inner backing plate 7A and the target 4A are reduced. By raising the potential of the probe 19 to near ground, it is possible to remove positively charged insulators such as oxides and nitrides by repelling each other on the surface of the probe 19 with each other. it can.

At this time, the spatter device 1 is
Is the same titanium material as the target, the oxides and nitrides attached to the probe 19 do not become impurities, so that the repelled insulator does not become contamination contamination.

As described above, the sputter device 1 generates spatter by generating plasma, and then insulates the oxide or nitride attached to the surface of the target 4A on the inner peripheral side, which is a non-erosion region, or the surface of the probe 19. Since the object can be easily removed, arcing caused by the insulator can be prevented.

The sputter device 1 applies a DC voltage V to a needle-like projection 19A provided at the tip of the probe 19 with reference to the vacuum chamber 2 kept at the ground potential during plasma generation. The electron temperature, electron density, and resistance value of the plasma can be calculated based on the Langmuir characteristic curve representing the relationship between the probe current I and the probe current I. Accordingly, the spatter device 1 detects the probe current I with the ammeter 25, calculates the resistance value based on the Langmuir characteristic curve, and controls the supply amount of the reactant gas based on the resistance value to obtain the plasma. According to the above configuration, the spatter device 1 is made of titanium of the same material as the inner target 4A and the outer target 4B. By using the conductor probe 19 formed by the above, the insulator attached to the probe 19 does not become an impurity, and even if the insulator is repelled by changing the potential of the probe 19 to a negative potential or a positive potential. Avoids contamination contamination.

Further, the spatter device 1 can easily remove the insulator attached to the non-erosion region by changing the potential of the inner target 4A, the outer target 4B, and the probe 19 independently of each other. Arcing can be prevented from occurring.

Further, the spatter device 1 calculates the resistance value based on the Langmuir characteristic curve obtained by the probe method, and controls the supply amount of the reaction gas based on the resistance value, thereby changing the state of the plasma. It is possible to form a stable and stable film on the surface of the substrate 3. In the above-described embodiment, the target and the backing plate are divided into two parts to form rubber O-rings 40 to 42 as insulating means. Thus, a case has been described in which the outer target 4B and the backing plate 7B are insulated from the inner target 4A and the backing plate 7A. However, the present invention is not limited to this, and any electrical insulation can be provided. You may make it insulate by other various insulation means. In this case, the same effect as in the above-described embodiment can be obtained.

In the above-described embodiment, the case where the outer target 4B as the first region and the inner target 4A as the second region are made of titanium of the same material has been described. The present invention is not limited to this, and the target 4A on the inner peripheral side may be made of another material different from titanium as long as the deposited insulator does not become an impurity and does not cause contamination contamination.

Further, in the above-described embodiment, the case where the annular magnets 16 and 17 are used as the magnetic field generating means has been described. However, the present invention is not limited to this.
As long as a magnetic field can be generated, other magnetic field generating means such as a coil may be used.

Further, in the above-described embodiment, the case where the material of the probe 19 as a conductor is made of titanium of the same material as the inner target 4A and the outer target 4B has been described. The present invention is not limited to this, and other various materials may be used as long as the conductor and the insulator attached to the probe 19 do not become impurities.

Further, in the above-described embodiment, the case where the potential of the target 4A on the inner peripheral side is adjusted to remove the adhered insulator has been described. However, the present invention is not limited to this, and the present invention is not limited to this. Alternatively, the potential of the target 4A may be reduced to a negative value to form an erosion region and be used as a sputter. In this case, the distribution of the film formed on the surface of the substrate 3 is constant.

Further, in the above embodiment, the case where the potential of the inner target 4A, the outer target 4B and the potential of the probe 19 can be independently changed has been described. The potential of the inner target 4A, the outer target 4B, and the potential of the probe 19 may all be set to the same potential. Thereby, the sputter device 1 can increase the film forming rate.

Further, in the above-described embodiment, a case has been described in which the nitride deposited on the inner peripheral side target 4A, which is a non-erosion region, is removed. However, the present invention is not limited to this. A nitride deposited by applying a negative potential may be used for the reactive sputter. Thereby, the film formation distribution on the surface of the substrate 3 can be made constant.

Further, in the above-described embodiment, the case where the potential of the probe 19 is made negative and the insulator attached by the impact of the collision of attracting and colliding particles having a positive charge is removed. As described above, the present invention is not limited to this. The probe 19 may be moved in the axial direction to remove the insulator attached by the impact applied to the housing of the vacuum chamber 2. Again, in this case,
Arcing can be prevented from occurring.

[0067]

As described above, according to the present invention, by providing a potential difference between a substrate and a target which are arranged opposite to each other at a position separated by a predetermined distance in a container to which a predetermined reaction gas is supplied. In a sputter apparatus for generating plasma, a target is divided into a first region and a second region, and a magnetic field generating means for generating a magnetic field on a surface of the first region of the target; a first region and a second region of the target. Insulating means for electrically insulating the first region of the target, voltage applying means for applying a voltage to the first region of the target, and applying voltage to the second region of the target independently of the first region of the target. And a first voltage control means for controlling.

Thus, when the sputtering is performed by generating the plasma, even if the insulator attached to the surface of the second region of the target has a positive charge and is charged, it is independent of the first region of the target. By controlling the potential of the second region of the target from the negative potential to the positive potential, the insulator adhered to the surface of the second region of the target can be removed, and thus the second region of the target and the substrate can be removed. Arcing that occurs can be prevented to form a stable film.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing the overall configuration of a spatter device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a cross-sectional structure of a target of the spatter device according to the embodiment of the present invention.

[Description of Signs] 1 ... sputter device, 2 ... vacuum chamber, 3 ... substrate, 4 ... target, 5 ... mechanical pump, 6 ...
... Turbo molecular pump, 7 ... Backing plate, 8 ...
... Insulation ring, 9, 13, 24 ... Variable cathode power supply, 1
0, 14, 25: ammeter, 11, 15: analog /
Digital converter, 12 ... Computer, 16, 17
... Magnet, 18 ... Shield plate, 19 ... Probe, 20 ... Linear motor shaft, 21 ... Probe moving motor, 22 ... Pulse generator, 23 ... Driver, 26 ... Gas control driver, 31 ... Neutralizer, 32... Neutralizer power supply, 40-42,
44, 45 ... O-ring.

Claims (4)

[Claims] 1. A sputter apparatus which generates a plasma by applying a potential difference between a substrate and a target which are arranged opposite to each other at a position separated by a predetermined distance in a container to which a predetermined reaction gas is supplied, wherein said target is Is divided into a first region and a second region, a magnetic field generating means for generating a magnetic field on the surface of the first region of the target, and a first region of the target and a second region of the target. Insulating means for electrically insulating; voltage applying means for applying a voltage to the first area of the target; and a voltage controlling means for controlling a voltage applied to the second area independently of the first area of the target. 1. A spatter device comprising: 2. A rod-shaped conductor made of the same material as the target, which is disposed in the container and has a projection at a predetermined position; a driving means for moving the conductor in the plasma; And a second voltage control means for controlling a voltage applied to the conductor independently of the first area of the target and the second area of the target. The spatter device according to claim 1, wherein 3. The spatter device according to claim 1, further comprising an electron emitting means for emitting electrons on the surface of the second area at a predetermined position in the container. 4. The apparatus according to claim 1, further comprising control means for adjusting a supply amount of the reaction gas based on an amount of current flowing from the plasma to the conductor when the conductor is set to a negative potential. The spatter device as described.