JP2000144411A - Sputttering device and formation of film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sputtering device capable of generating the suitable magnetic field for allowing self-sputtering to stably occur and to provide a film forming method. SOLUTION: This device is provided with a vacuum chamber 12, a pedestal 18 for supporting a substrate 15 in the vacuum chamber 12, a target 16 provided in such a manner that an erosion face 16a is confronted with the substrate 15 supported by the pedestal 18, a gas feeding means 22 for feeding process gas into the vacuum chamber 12, a plasmatizing means for plasmatizing the fed process gas, a pressure reducing means 21 for reducing the pressure in the vacuum chamber 12, a magnetron unit 30 arranged on the side opposite to the erosion face 16a and a coil 27 in which a lead wire is coiled around a reference axis connecting the erosion face 16a and the surface of the substrate 15. By the magnetic field, the ionization of the particles to be sputtered is promoted, and self-sputtering stably occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a sputtering apparatus and a film forming method.

[0002]

2. Description of the Related Art With the recent increase in the degree of integration of semiconductor devices, wiring patterns have become finer, and it has become difficult to efficiently form wiring films in contact holes, via holes, and the like by sputtering. For example, in a standard magnetron sputtering apparatus, when a film is formed on the surface of a semiconductor wafer having the fine holes, an overhang occurs at the entrance of the hole,
There is a problem that the bottom coverage ratio is impaired.

[0003]

In order to solve this problem, techniques such as collimation sputtering and remote sputtering have been developed. In addition, the self-sputtering (self-sputtering) method has advantages that are not found in the collimation sputtering method and the remote sputtering method, and is therefore promising as a technology for solving such a problem in the future.

[0004] The self-sputtering phenomenon refers to a phenomenon in which ions for sputtering a target are generated by particles themselves sputtered from the target.
In order to utilize this phenomenon for sputtering, first,
It is necessary to introduce argon as a process gas to generate sputtered particles in the same manner as before, and to shift to self-sputtering, then stop the supply of the process gas so that sputtering proceeds only by self-sputtering. It is.

[0005] However, since there is a part of the mechanism of self-sputtering that has not been elucidated, there is a need to stably control self-sputtering.

Accordingly, an object of the present invention is to provide a sputtering apparatus capable of generating an appropriate magnetic field for stably generating self-sputtering, and a film forming method using self-sputtering.

[0007]

The inventor has conducted various trials and errors in order to apply self-sputtering to a film forming technique. As a result, conventionally, a design has been performed on an argon sputtering target so as to increase a magnetic field component in a direction horizontal to the surface of the target. However, in order to facilitate self-sputtering,
It became clear that it was necessary to make the magnetic field component in the direction perpendicular to the target surface higher than that in the horizontal direction. On the other hand, if the magnetic field component in the vertical direction that easily causes self-sputtering is increased, it becomes difficult to lower the discharge voltage of argon. For this reason, it has been found that the generation of plasma necessary for maintaining sputtering may be interrupted during the transition to self-sputtering. Therefore, the inventor concluded that in order to solve such a problem, it is necessary to appropriately generate and control a magnetic field for sputtering.

Therefore, the present invention has the following configuration.

A sputtering apparatus according to the present invention comprises: a vacuum chamber; support means for supporting a substrate in the vacuum chamber; a target provided such that an erosion surface faces the substrate supported by the support means; Gas supply means for supplying a process gas into the vacuum chamber, plasma generating means for converting the process gas supplied into the vacuum chamber into plasma, pressure reducing means for reducing the pressure in the vacuum chamber, and erosion of the target A sputtering apparatus comprising: a surface and a magnetron unit disposed on opposite sides, wherein two ends are formed around a reference axis connecting an erosion surface of the target and a surface of the substrate supported by the support means. And a coil having a conductive wire wound therearound.

[0010] In such a sputtering apparatus, the process gas is converted into plasma near the erosion surface by the magnetron unit. For this reason, target particles are sputtered from the erosion surface of the target. In addition, since a coil formed by winding a conductive wire around the reference axis is provided, a magnetic field in which the magnetic field component in the direction perpendicular to the erosion surface is larger than the magnetic field component in the horizontal direction is generated in the erosion surface in the vacuum chamber. It is generated in an area different from the vicinity. The sputtered particles are efficiently ionized in regions within the vacuum chamber where the vertical component is dominant over the horizontal component. For this reason,
Particles ionized by the magnetic field generated using the coil are accelerated toward the erosion surface and collide with the erosion surface to generate another sputtered particle. Therefore, self-sputtering occurs continuously.

In the sputtering apparatus according to the present invention,
A control unit for controlling operations of the gas supply unit, the plasma generation unit, the magnetron unit, and the coil may be further provided.

By providing the control unit in this way, the operations of the gas supply means, the plasma generating means, the magnetron unit, and the coil can be controlled in relation to each other. For this reason, the conditions for efficiently causing self-sputtering and the conditions for smoothly shifting to self-sputtering can be set finely.

[0013] In the sputtering apparatus according to the present invention,
A coil power supply connected to one end and the other end of the conducting wire and capable of generating a pulse voltage may be further provided.

As described above, when the pulse voltage can be generated, the generated magnetic field is changed according to the value of the pulse voltage. Therefore, when the magnetic field is sufficiently large, self-sputtering is sufficiently generated, and a large number of sputtered particles are generated. In low or no magnetic fields, the sputtered particles reach the surface of the substrate and form a film thereon.

[0015] A film forming method according to the present invention is a film forming method for forming a film using particles sputtered from a target by particles sputtered from a target provided in a vacuum chamber. Placing a substrate having a surface to be placed in a vacuum chamber;
A supply step of supplying a process gas into the vacuum chamber,
A plasma process for forming a process gas plasma near the erosion surface to generate sputtering particles from the target, and a magnetic field along a reference axis connecting the erosion surface of the target and the surface of the substrate between the target and the substrate. A sputtering step of generating sputtered particles from the target by self-sputtering and generating a film on the substrate, and a stopping step of stopping supply of process gas.

As described above, since the plasma of the process gas is formed near the erosion surface, particles sputtered from the erosion surface are generated. Since a magnetic field along the reference axis connecting the erosion surface of the target and the surface of the substrate is generated in a region between the target and the substrate, particles sputtered from the target are ionized. When the ionized particles reach the erosion surface, another particle is sputtered.
Since the sputtered particles are generated in this way, the self-sputtering proceeds continuously even when the supply of the process gas is stopped. Some of the particles sputtered from the target travel along the reference axis and reach the surface of the substrate on which the film is to be formed. Therefore, particles generated by self-sputtering are sequentially deposited on the surface of the substrate. Therefore, a film with good bottom coverage is deposited on the substrate.

In the film forming method according to the present invention, the film forming step may include a step of generating a magnetic field in a pulse shape.

As described above, when the magnetic field is generated in a pulse shape, self-sputtering and film formation alternately proceed. That is, when the magnetic field is sufficiently large, self-sputtering occurs sufficiently, and a large number of sputtered particles are generated. When the magnetic field is small or no magnetic field, the sputtered particles reach the surface of the substrate,
A film is formed thereon.

[0019]

Embodiments of the present invention will be described with reference to the drawings. When possible, the same parts are denoted by the same reference numerals and description thereof will be omitted.

A description will be given of a sputtering apparatus according to an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a magnetron type sputtering apparatus according to the present invention. The sputtering apparatus 10 includes a housing 14 in which a vacuum chamber 12 is formed, and a target 16 arranged to close an upper opening of the housing 14. Since the housing 14 and the target 16 are both made of a conductive material, an insulating member 13a is interposed between the housing 14 and the target 16. In the embodiment shown in FIG. 1, the housing 14 has a circular bottom surface and a tubular portion extending a predetermined distance from the periphery of the circular bottom surface. For example, the tubular portion has a cylindrical shell shape.
The shape of the target 16 is a disk shape. Target 16
The circular one surface 16a (hereinafter referred to as the lower surface) is an erosion surface that receives erosion by sputtering.

In the vacuum chamber 12, a pedestal 18 is provided as a support means. Pedestal 18
Supports the substrate 15 in the vacuum chamber 12.
For this reason, the pedestal 18 is placed on the substrate 1 to be processed.
5, for example, a semiconductor wafer W is held on one surface (hereinafter referred to as an upper surface) 18a. Pedestal 18
Is arranged so as to face the lower surface 16 a of the target 16. A surface 15 a of the substrate 15 (wafer W) to be deposited, which is held at a predetermined position on the pedestal 18, is arranged parallel to the lower surface 16 a of the target 16. The center of the substrate 15 is the target 1
6 are arranged so as to be centered. In the present embodiment, the dimensions of the target 16 and the distance between the pedestal 18 and the target 16 can have the same values as in a conventional standard sputtering apparatus.

The sputtering apparatus 10 has a shield 26 for preventing the sputtered particles from reaching the inner wall surface in order to protect the inner wall surface of the vacuum chamber 12 from the sputtered particles. One edge of the shield 26 is sandwiched between the housing 14 and the insulating member 13a, and one edge of the shield 26 is fixed at the edge of the upper opening of the housing. The shield 26 extends from one edge of the shield 26 and another side reaches the side of the pedestal 18. The other edge is fixed along the side surface of the pedestal 18 via an insulating member 13b. For this reason, the shield 26 is electrically insulated from the pedestal 18.

The housing 14 has an exhaust port 20 formed therein. In the case of the present embodiment, the exhaust port 2
0 is connected to a vacuum pump 21 such as a cryopump. By operating the vacuum pump 21, the pressure inside the vacuum chamber 12 can be reduced. The exhaust port 20 and the vacuum pump 21 constitute a pressure reducing unit. Argon gas as process gas, supply port 2
From the process gas supply source 25 through the vacuum chamber 1
2. The supply port 22 can be opened and closed by a valve 23. By opening and closing the valve 23, the supply amount and supply timing of the process gas can be controlled. The supply port 22 and the process gas supply 25 source
It constitutes gas supply means.

A cathode and an anode of an accelerating power supply 24 are connected to the target 16 and the shield 26, respectively, as plasma generating means. When an argon gas, which is a process gas, is introduced into the vacuum chamber 12 and a voltage is applied between the target 16 and the shield 18, glow discharge occurs and a plasma state is created. When the argon ions generated by this discharge collide with the lower surface 16a of the target 16, atoms (sputtered particles) constituting the target 16 are repelled. When the target atoms reach and accumulate on the wafer W, a thin film is formed on the wafer W.

On the opposite side of the lower surface 16a of the target 16, that is, above the target 16, the target 16
A magnetron unit 30 for increasing the plasma density in the vicinity of is provided. FIG. 2 is a top view showing the arrangement position of each magnetron unit. Referring to FIG. 2, the magnetron unit 30 includes a circular base plate 32 and a plurality of magnets 34 fixed on the base plate 32 in a predetermined arrangement. The base plate 32 is disposed above the target 16, and a rotation shaft 38 of a driving motor 36 is connected to a center of an upper surface of the base plate 32. Therefore, when the drive motor 36 is operated to rotate the base plate 32, each magnet 34
Can be turned along the upper surface of the target 16 to prevent the magnetic field generated by the magnet 34 from stopping at one place.

FIG. 3 is an enlarged view of a magnetron unit in which a portion of one magnet is enlarged. As shown in FIG. 3, each magnet 34 includes a flat yoke member 40 made of a ferromagnetic material, and bar magnets 42 and 44 fixed to each end of the yoke member 40. The two bar magnets 42 and 44 extend in the same direction, and the entire shape of the magnet 34 is substantially U-shaped. The free end of one bar magnet 42 has an N pole, and the free end of the other bar magnet 44 is free. The end is an S pole.

Each magnet 34 (34o, 34i)
These free ends correspond to the lower surface 16a of the target 16, respectively.
The target 16 is disposed above the target 16 so as to face the surface 16b that faces the target. Such a magnet 34
The yoke member 40 is fixed to the base plate 32 by a suitable fixing means, for example, screws 46 in a state where the back surface of the yoke member 40 is in contact with the base plate 32. In such a configuration,
The fixed position of the magnet 34 can be freely changed. Although various arrangements of the magnets 34 are conceivable, in the illustrated embodiment, the magnets 34 have a double annular arrangement as shown in FIG. The all annular magnet includes an inner annular magnet 34i group (the subscript i represents an inner annular array) and an outer annular magnet 34i.
o (subscript o represents the outer ring arrangement). Each magnet 34i, 34o is located on the lower surface 1 of the target 16.
By forming a magnetic field in the space near 6a, the plasma of the process gas formed in the space can be controlled.

Referring again to FIGS. 1 and 2, the sputtering apparatus 10 further includes a coil 27. The coil 27 is connected to the vacuum chamber 12 of the sputtering apparatus 10.
And is disposed along the outer surface of the housing 14. In the embodiment shown in FIGS. 1 and 2, the coil 27 has a conductor 27 c having two ends 27 a and 27 b wound a plurality of times around the side surface of the housing 14. Both ends 27a, 27 of the conducting wire 27c
b is connected to the cathode and anode of the coil power supply 28, respectively.

The coil 27 extends in one direction along the reference axis while the conductor 27c is sequentially wound around a predetermined reference axis. The predetermined reference axis is the target 16
Is preferably determined as one of the axes connecting the erosion surface 16a of the wafer W and the surface of the wafer W supported by the pedestal 18. This reference axis is pedestal 1
It is preferable to pass through the center point of the wafer W arranged on the upper surface of the wafer 8. Such a reference axis is a direction that forms a predetermined angle with the erosion surface because the coil 27 is intended to mainly generate a magnetic field component perpendicular to the erosion surface in the vacuum chamber 12. The direction is preferably perpendicular to the erosion surface. Since such a coil 27 can confine a magnetic field in an inner hollow portion, it is preferable to be a solenoid coil. The solenoid coil 27 suitable for the present embodiment includes a solenoid coil 2 extending from a lower end of the solenoid coil 27 around a reference axis.
The conductor 27c is formed by winding the conductor 27c in order until the upper end of the conductor 7 is reached. It has a hollow region with a circular cross section, in which the vacuum chamber 12 is arranged. In the present embodiment, the solenoid coil 27 is formed as a single coil, but may be formed as a coil group (solenoid coil group) including a plurality of coils wound around the same reference axis. it can.

The solenoid coil 27 or the group of solenoid coils is arranged such that a plane including the upper end thereof is parallel to the erosion surface 16a and a plane including the lower end thereof is formed on the upper surface 18a of the pedestal 18, ie, the wafer W.
Are arranged so as to be parallel to the surface. With this arrangement, the magnitude of the component of the magnetic field H generated by the solenoid coil 27 in the direction of the reference axis (vertical component Hv) can be maximized.

The positions of the upper end and the lower end of the solenoid coil 27 determine the length of the coil 27. This length corresponds to the erosion surface 16a and the upper surface 1 of the pedestal 18.
8a mainly controls the ratio of the vertical component Hv of the magnetic field H formed in the space inside the vacuum chamber 12 (hereinafter referred to as a self-sputtering space) to the horizontal component Hh. If the solenoid coil 27 is formed relatively long in the direction of the reference axis, the magnetic field is confined in the hollow portion, so that a magnetic field component parallel to the reference axis is efficiently generated. For this reason,
At each point in the self-sputtering space apart from both ends of the solenoid coil 27, the vertical component H of the magnetic field H
v can be made larger than the horizontal component Hh.

The number of turns in the radial direction of the coil determines the thickness of the coil. The number of turns mainly governs the strength of the magnetic field H at each point in the self-sputtering space. Therefore, when the magnetic field H is increased, the magnitude of the vertical component Hv also increases in proportion to the intensity. For this reason, in order to increase the vertical component Hv of the magnetic field H at each point in the self-sputtering space, particularly at an intermediate region between the erosion surface 16a and the upper surface 18a of the pedestal 18, the winding of the solenoid coil 27 in the body radial direction is required. It is preferable to increase the number.

The solenoid coil 2 thus formed
7 is an erosion surface 1 according to the direction of the applied current.
Direction from 6a to the upper surface 18a of the pedestal 18,
Alternatively, the magnetic field H is generated in a direction from the upper surface 18a of the pedestal 18 toward the erosion surface 16a, that is, a direction along the reference axis. This magnetic field H is preferably generated in many regions of the self-sputtering space so as to satisfy Hv >> Hh, that is, the relationship that the vertical component is sufficiently larger than the horizontal component.

In such a sputtering apparatus, the process gas is turned into plasma near the erosion surface 16a by the magnetron unit 30. Therefore, particles to be sputtered are generated from the erosion surface 16a of the target 16. Further, since the coil 27 formed by winding a conductive wire around the reference axis is provided, a magnetic field such that a magnetic field component in the vertical direction on the erosion surface 16a is larger than a magnetic field component in the horizontal direction is applied to the vacuum chamber 12.
Is generated in a region different from the vicinity of the erosion surface 16a. The sputtered particles are efficiently ionized in regions within the vacuum chamber 12 where the vertical component is dominant over the horizontal component. For this reason, the coil 27
Particles ionized by the magnetic field generated using are accelerated toward the erosion surface 16a, and collide with the erosion surface 16a to generate another sputtered particle. Therefore, self-sputtering occurs continuously.

The power supply 28 for the solenoid coil is connected to the controller 2
9 is connected. As described above, since the controller 29 includes the microcomputer, the timer, and the like, the control of turning on and off the current, the change of the current value, and the like can be performed including the temporal control. The controller 29 also controls the valve 2
3, the power supply 24 for acceleration, and the motor 36 for driving. Therefore, similar control can be performed for these devices. Further, the valve 23, the acceleration power supply 24, the solenoid coil power supply 28, and the drive motor 36 are connected to the same controller 29 via the control line 29a, so that these devices can be interconnected. You can control. Therefore, the supply of the process gas, the generation of the plasma of the process gas, the shift to the self-sputtering, and the like can be controlled in synchronization with a predetermined timing.

The coil power supply 28 may be a power supply capable of generating a pulse voltage. As described above, when the pulse voltage can be generated, the generated magnetic field is changed according to the value of the pulse voltage. Therefore, when the magnetic field is sufficiently large, self-sputtering is sufficiently generated, and a large number of sputtered particles are generated. When the magnetic field is low or when there is no magnetic field, the sputtered particles reach the surface of the substrate and form a film thereon.

Referring to FIG. 4, the mechanism by which self-sputtering occurs in the sputtering apparatus of the present embodiment will be described. FIG. 4 is a configuration diagram showing a magnetic field formed in the sputtering apparatus 10 shown in FIG. In FIG. 4, the magnetic fields generated by each of the magnets 34 and the solenoid coils 27 of the magnetron unit 30 are indicated by broken lines. Since the magnetron unit 30 is rotated by the drive motor 36, the magnetic fields generated by the magnets 34i and 34o rotate around the drive shaft 38 in an actual sputtering apparatus.

In the following description, the case where the target is mainly copper is described. That is, a copper thin film is deposited on the wafer W by sputtering. However, the target material to which the sputtering apparatus 10 of the present embodiment is applied is not limited to copper. Other elements can be used to form a film using self-sputtering.

Each magnet 34 (34i, 34o) of the magnetron unit 30 forms a toroidal magnetic field A as shown by a broken line in FIG.
In the vicinity of the erosion surface 16a of the target 16, the annular magnetic field A is mainly composed of a component Hah (horizontal component) of a magnetic field parallel to the surface 16a. Since this magnetic field component Hah acts to increase the plasma density formed by the discharge of argon in the vicinity of the erosion surface 16a of the target 16, in a region where the magnetic field component Hah is large (broken line region P in FIG. 1), argon is applied. Sputtering is promoted. However, the magnetic field component Hah does not promote ionization, that is, plasmaization of the particles to be sputtered Cu.

On the other hand, between the erosion surface 16a and the upper surface 18a of the pedestal 18, the erosion surface 16a
In a self-sputtering space at a location different from the area near a, a magnetic field B is generated by the solenoid coil 27. The magnetic field B is applied to the solenoid coil 2 in this space.
The main component is a magnetic field component (vertical component) Hbv directed in the axial direction of No. 7. This component is a magnetic field component Hbv perpendicular to the erosion surface 16a. The magnetic field component Hbv has an effect of promoting the ionization of copper atoms Cu by desorbing electrons from copper atoms Cu (particles to be sputtered) having a velocity component perpendicular to the erosion surface 16a. Therefore, the magnetic field B generated by the solenoid coil 27
Works as follows.

First, the copper atom Cu sputtered by argon proceeds in the self-sputtering space toward the wafer W. On the way, under the action of the vertical component Hbv of the magnetic field B, the copper atoms Cu are ionized at a certain ratio to generate copper ions Cu ⁺ . The ionized copper Cu ⁺ interacts with an electric field from the shield 26 to the target 16 and receives Coulomb force. For this reason, an atom whose kinetic energy at the time of ionization is smaller than the potential energy changes its motion direction to the direction of the erosion surface 16 a of the target 16. And
It is accelerated according to the potential energy of each Cu ⁺ and collides with the erosion surface 16a with kinetic energy at the time of ionization and kinetic energy according to the potential energy. If the energy during this collision is sufficient to sputter another atom from the target, the next atom to be sputtered is produced by sputtering with Cu ⁺ . These atoms travel in the self-sputtering space toward the wafer W according to their initial velocity.

That is, (1) generation of copper atom Cu by sputtering, (2) flight of the generated copper atom in a magnetic field,
(3) ionization of this Cu atom by a vertical magnetic field component, (4)
Acceleration of copper ion Cu ⁺ by electric field, (5) This copper ion Cu
^The process proceeds in the following order: ⁺ collision with the target, (6) generation of another copper atom by self-sputtering, (7) flight of the generated copper atom in a magnetic field. Some of the generated copper atoms, including those that have been ionized and those that have not been ionized, reach the surface of the wafer W and are deposited there.

When such a process proceeds and the number of ionized copper ions becomes larger than the number of non-ionized copper atoms, self-sputtering is maintained.
However, if the supply of the argon gas is stopped to reduce the number of copper atoms generated by the process gas, the number of copper atoms and copper ions may not be sufficient and self-sputtering may not occur. On the other hand, if the state where the number of ionized copper ions is larger than the number of non-ionized copper atoms is maintained without supplying the process gas, self-sputtering is maintained. In this state, sputtering proceeds without supplying argon gas as a process gas. That is, self-sputtering is in progress. In order to adjust such a condition, it is important that a magnetic field component perpendicular to the target exists. It is also important that the argon gas be appropriately turned into plasma to initially supply copper atoms until reaching this state.

A method for suitably realizing such a self-sputtering phenomenon in the sputtering apparatus of the present embodiment will be described. FIG. 5 shows a timing chart for operating the sputtering apparatus. FIG. 5 shows the control of the argon flow rate performed by the valve 23,
The control of the voltage (power) between the target 16 and the shield 26 and the control of the magnetic field of the coil 27 are shown on the time axis on the horizontal axis.

Referring to FIG. 5, at time t ₀ , a voltage is applied between the target 16 and the shield 26 from the power supply 24. At time t ₁ , the valve 23 is opened to start supplying a process gas (argon gas) into the vacuum chamber 12. At time t ₂ , since the degree of vacuum suitable for glow discharge has been reached, the bulb 23 is fixed.
In the process so far, and in the future, vacuum evacuation is continuously performed by a vacuum pump. Although not shown in FIG. 3, when the magnetron unit 30 is operated, argon plasma is efficiently formed near the erosion surface 26a (P region in FIG. 1). At this time, the power supply 24
, Power P1 is supplied. The erosion surface 1 of the target 16 is formed by the action of the argon plasma.
From 6a, sputtered copper atoms are generated.
This state is schematically shown in FIG. That is, the argon ions collide with the target, and copper atoms are sputtered (normal sputtering state).

Next, from time t ₃ to time t ₄ , the power is further increased from the power supply 24. Power at time t ₄ is a P2. At this time, sputtering by argon is maintained.

Subsequently, a magnetic field B is generated at time t ₅ , and is gradually increased until time t ₆ . In this process, when the magnetic field B reaches a certain value, self-sputtering starts. At this time, the sputtered copper atoms include those due to argon ions and those due to copper ions themselves. However, since the magnetic field B is generated so as to have an appropriate direction, the condition for maintaining the self-sputtering is satisfied. This state is
This is schematically shown in FIG. In other words, a case where the copper ions are sputtered by colliding with the target and a case where the copper ions are sputtered by colliding with the target coexist (the transition state).

On the other hand, the flow of argon is started to be reduced from time t ₇ , and the supply of argon is stopped at time t ₈ . At time t _6, when the supply of the process gas is completely stopped, the copper atoms only by self-sputtering is supplied. This state is schematically shown in FIG. In other words, copper ions collide with the target,
Copper atoms are sputtered (self-sputtering state).

As described above, after the process gas plasma is generated and the sputtered particles are generated by the plasma, a vertical magnetic field is generated to ionize the sputtered particles. Therefore, it is possible to shift from the normal sputtering state to the transition state. In the transition state, since the plasma region of the process gas is different from the ionization region of the particles to be sputtered, self-sputtering proceeds stably without mutual interference. Therefore, the self-sputtering state is maintained even if the plasma of the process gas is removed.

As described above, according to the self-sputtering method, the step of supplying the process gas into the vacuum chamber, the step of converting the process gas into plasma near the erosion surface of the target, and the step of forming a predetermined angle with the substrate surface are performed. Generating a magnetic field along the reference axis in the vacuum chamber. Such a predetermined angle is preferably perpendicular to the substrate surface to which the particles to be sputtered should reach.

As described above, after the process gas is supplied into the vacuum chamber 12, the process gas is turned into plasma in a region near the erosion surface 16a of the target 16, so that particles to be sputtered are generated from the erosion surface 16a. You. Erosion surface 1
Since a magnetic field along a reference axis substantially perpendicular to 6a is generated in a region in the vacuum chamber 12 different from the above-described neighboring region, a magnetic field component in a direction parallel to the reference axis is smaller than a component perpendicular to the reference axis. A dominant region is formed in the vacuum chamber 12. Within this region, the sputtered particles are easily ionized. The ionized particles are accelerated toward the target 16, and when the particles reach the erosion surface 16a, generate another sputtered particle. For this reason, self-sputtering proceeds continuously with normal sputtering.

When the supply of the process gas is stopped,
The degree of vacuum is increased by the partial pressure of the process gas. On the other hand, since the predetermined magnetic field is generated in the magnetic field generating step, the generation of the particles to be sputtered is maintained by the self-sputtering without the supply of the process gas. Also,
The process gas particles do not collide with the sputtered particles.

Further, when the plasma process is performed prior to the magnetic field generating step, the plasma of the process gas can be generated stably regardless of the magnitude and direction of the magnetic field generated in the magnetic field generating step. After that, if the magnetic field generation step is performed, it is possible to smoothly shift to self-sputtering based on the sputtered particles generated in the plasma step.

As described above, since the plasma of the process gas is formed near the erosion surface, particles sputtered from the erosion surface are generated. Since a magnetic field along the reference axis connecting the erosion surface of the target and the surface of the substrate is generated in a region between the target and the substrate, particles sputtered from the target are ionized. When the ionized particles reach the erosion surface, another particle is sputtered.
Since the sputtered particles are generated in this way, the self-sputtering proceeds continuously even when the supply of the process gas is stopped. Some of the particles sputtered from the target travel along the reference axis and reach the surface of the substrate on which the film is to be formed. Therefore, particles generated by self-sputtering are sequentially deposited on the surface of the substrate. Therefore, a film with good bottom coverage is deposited on the substrate.

When such self-sputtering is applied to a film forming method, the following is obtained. A method for forming a film using particles sputtered from a target by particles sputtered from a target provided in a vacuum chamber, wherein a substrate having a surface to be formed is disposed in the vacuum chamber. A process of supplying a process gas into a vacuum chamber, a plasma process of forming a plasma of the process gas in the vicinity of the erosion surface to generate sputtered particles from the target, and an erosion surface of the target and a surface of the substrate. A self-sputtering step of generating a magnetic field along the reference axis connecting the target in the space between the erosion surface of the target and the surface of the substrate to generate sputtered particles from the target by self-sputtering, and after the self-sputtering step, the process Gas supply Comprising a stopping step of stopping, the.

As described above, when the particles generated by the self-sputtering are sequentially deposited on the surface of the substrate,
A film with good bottom coverage is deposited on the substrate. In addition, even when the process gas is not supplied, the generation of the particles to be sputtered is maintained by the self-sputtering because the appropriate magnetic field and current are applied. on the other hand,
When the supply of the process gas is stopped, the degree of vacuum increases by the partial pressure of the process gas. Because the process gas particles do not collide with the sputtered particles,
The bottom coverage ratio is further improved. In addition, when a magnetic field is generated in a pulsed manner, self-sputtering and film formation alternately proceed. That is, when the magnetic field is sufficiently large, self-sputtering occurs sufficiently, and a large number of sputtered particles are generated. In low or no magnetic fields, the sputtered particles reach the surface of the substrate and form a film thereon.

[0057]

As described above in detail, in the sputtering apparatus according to the present invention, the process gas is turned into plasma near the erosion surface by the magnetron unit. For this reason, target particles are sputtered from the erosion surface of the target. In addition, since a coil formed by winding a conductive wire around the reference axis is provided, a magnetic field in which the magnetic field component in the direction perpendicular to the erosion surface is larger than the magnetic field component in the horizontal direction is generated in the erosion surface in the vacuum chamber. It is generated in an area different from the vicinity. The sputtered particles are efficiently ionized in regions within the vacuum chamber where the vertical component is dominant over the horizontal component. For this reason, the particles ionized by the magnetic field generated using the coil are accelerated toward the erosion surface, and when the particles collide with the erosion surface, another sputtered particle is generated. Therefore, self-sputtering occurs continuously.

That is, according to the sputtering apparatus of the present invention, it is possible to form a magnetic field capable of spatially separating the process gas into plasma and the ionization of particles to be sputtered. In addition, a magnetic field suitable for ionizing the particles to be sputtered can be generated without significantly affecting the process gas into plasma. Therefore, the process gas discharge can be generated at a relatively low voltage. In addition, this discharge was prevented from being cut off during the transition to the self-sputtering.

Further, in the film forming method according to the present invention, since the sputtered particles are generated by applying the above-described self-sputtering, the self-sputtering is continuously performed even when the supply of the process gas is stopped. Be advanced. Some of the particles sputtered from the target travel along the reference axis and reach the surface of the substrate on which the film is to be formed. Therefore, particles generated by self-sputtering are sequentially deposited on the surface of the substrate. Therefore, a film with good bottom coverage is deposited on the substrate.

Accordingly, a sputtering apparatus capable of generating an appropriate magnetic field for stably generating self-sputtering, and a film forming method using self-sputtering are provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a magnetron type sputtering apparatus according to the present invention.

FIG. 2 is a top view showing an arrangement position of each magnetron unit.

FIG. 3 is an enlarged view of a magnetron unit in which a portion of one magnet is enlarged.

FIG. 4 is a configuration diagram showing a magnetic field formed in a sputtering apparatus according to the present invention.

FIG. 5 shows a timing chart for operating the sputtering apparatus.

FIG. 6 is a schematic diagram for explaining a normal sputtering state, a transition state, and a self-sputtering state.

[Description of Signs] 10: sputtering apparatus, 12: vacuum chamber, 13
a, 13b: insulating member, 14: housing, 15: substrate, 16: target, 18: pedestal, 20: exhaust port, 21: vacuum pump, 22: supply port, 23
... Valve, 24 ... Power supply for acceleration, 25 ... Process gas supply source, 26 ... Shield, 27 ... Coil, 28 ... Power supply for solenoid coil, 29 ... Controller, 30 ... Magnetron unit, 32 ... Base plate, 34 ... Magnet, 36
... drive motor, 38 ... drive motor, 40 ... yoke member, 42, 44 ... bar magnet,

[Procedure amendment]

[Submission date] May 17, 1999 (1999.5.1
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuichi Wada 14-3 Shinizumi, Narita-shi, Chiba Pref. In Nogedaira Industrial Park Applied Materials Japan Co., Ltd. F-term (reference) 4K029 BD02 DC33 DC45 EA09 4M104 BB04 5F103 AA08 BB14 BB22 BB59 DD28 NN05

Claims (5)

[Claims] A vacuum chamber; supporting means for supporting a substrate in the vacuum chamber; a target provided such that an erosion surface faces the substrate supported by the supporting means; A gas supply unit for supplying a process gas to the process chamber; a plasma generating unit for converting the process gas supplied into the vacuum chamber into a plasma; a depressurizing unit for depressurizing the vacuum chamber; The erosion surface is a sputtering apparatus including: a magnetron unit disposed on the opposite side; wherein a reference axis connecting the erosion surface of the target and the surface of the substrate supported by the support means is disposed around a reference axis. A coil wound around a conductive wire having two ends. 2. The apparatus according to claim 1, further comprising a control unit for controlling the operation of the gas supply unit, the plasma generating unit, the magnetron unit, and the coil.
3. The sputtering apparatus according to 1. 3. The sputtering apparatus according to claim 1, further comprising a coil power supply connected to one end and the other end of the conductive wire and capable of generating a pulse voltage. 4. A film forming method for forming a film using particles sputtered from a target provided in a vacuum chamber by using particles sputtered from the target, wherein a substrate having a surface on which a film is to be formed is formed. Disposing the process gas in the vacuum chamber; supplying the process gas into the vacuum chamber; and forming a plasma of the process gas in the vicinity of the erosion surface to generate sputtered particles from the target. And generating a magnetic field along a reference axis connecting the erosion surface of the target and the surface of the substrate in a space between the target and the substrate, thereby generating sputtered particles from the target by self-sputtering. Forming a film on the substrate; Film forming method and a stopping step of stopping the supply of the process gas. 5. The film forming method according to claim 1, wherein the film forming step includes a step of generating the magnetic field in a pulse shape.