JP2001262323A - Film deposition method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film deposition method and a device therefor by which, e.g., a wiring film having high crystal orientation properties and electric characteristics can be provided. SOLUTION: A plasma gun 30 is operated so that a plasma beam PB is not made incident on a hearth 51, and the electric potential of the face to be film-deposited in a substrate W is held to about 0 to -200 V by a substrate power source device 68. In this way, the face to be film-deposited in the substrate W is cleaned. After that, the plasma beam PB is fed to the hearth 51 to evaporate a film material in the hearth 51, so that a metallic wiring material film good in step coverage, in which voids or the like are hard to be formed and also good in crystal orientation properties can be deposited on the substrate W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming method and apparatus for performing ion plating using plasma, and more particularly to a film forming method and apparatus suitable for forming a metal wiring film or the like with good orientation.

[0002]

2. Description of the Related Art As a conventional film forming apparatus, a plasma beam from a pressure gradient type plasma gun is guided to a hearth, and a deposition material in an evaporating crucible on the hearth is evaporated and ionized. There is known an ion plating apparatus that attaches a substance to a surface of a substrate arranged opposite to a hearth.

Japanese Patent Application Laid-Open No. 7-138743 discloses an ion plating apparatus of this type in which an incident beam direction adjusting means is composed of a bar magnet arranged in a hearth and a permanent magnet arranged concentrically around the hearth. Which form a cusp magnetic field above the incident surface of the hearth. In this ion plating apparatus, the plasma beam incident on the hearth is corrected by the cusp magnetic field above the hearth, and the plasma beam is linearly incident from directly above the hearth, so that the thickness of the film formed on the surface of the substrate is uniform. Can be

[0004]

In the above-mentioned ion plating apparatus, a metal wiring film or the like having a higher crystal orientation than conventional film forming apparatuses has been obtained. However, due to the fact that impurity gas is adsorbed on the surface of the substrate before film formation, this adsorbed substance is taken into the film, not only increasing the amount of impurities but also deteriorating the crystal orientation. Let me.

Accordingly, the present invention provides a film forming method and apparatus capable of eliminating the influence of these adsorbed substances and providing a wiring film or the like having higher crystal orientation and excellent electric characteristics. Aim.

[0006]

In order to solve the above-mentioned problems, a film forming method according to the present invention applies a predetermined processing bias voltage to a substrate to cause ions in plasma to be incident on the substrate. A first step of surface treatment;
After the step, a second step of evaporating the film material of the material evaporation source by supplying a plasma beam toward the material evaporation source arranged in the film formation chamber and attaching the film material to the surface of the substrate.

In the above method, in the first step, ions in the plasma are incident on the substrate by applying a predetermined processing bias voltage to the substrate, and the substrate is subjected to surface treatment. Gas components and the like can be easily and reliably removed. Therefore, in the second step, a film having high orientation and good electric characteristics can be formed over a clean substrate.

[0008] In a preferred embodiment of the above method, the second method
The step includes a step of controlling the progress of film formation by applying a predetermined control bias voltage to the substrate during the step.

In this case, the film formation can be advanced while appropriately balancing the sputtering of the film formed on the substrate surface by ions and the adhesion of the film material to the substrate surface.
The embedding of the film material into the grooves and holes on the substrate is assured.

[0010] In a preferred embodiment of the above method, the ion contains at least one of Ar, H, He, Ne, Kr, and Xe;
V energy.

In this case, ions suitable for cleaning the substrate can be made incident on the substrate with the energy required for cleaning.

In a preferred embodiment of the above method, the second method
In the process, the plasma beam is supplied from the pressure gradient type plasma gun toward the hearth while controlling the magnetic field above and adjacent to the hearth holding the material evaporation source.

In this case, the plasma beam incident on the hearth at a high density from the pressure gradient type plasma gun is corrected by a magnetic field control member with a cusp-shaped magnetic field or the like, so that a film having a more uniform thickness can be quickly formed.

Further, the film forming apparatus of the present invention has a plasma source for supplying a plasma beam into a film forming chamber and a material evaporation source capable of storing a film material. And a substrate support device that supports the substrate in the film formation chamber so as to face the hearth, and is supported by the substrate support device before the plasma beam is supplied to the material evaporation source and film formation is performed. Potential control means for applying ions in a plasma beam from a plasma source to the substrate by applying a bias voltage to the substrate, thereby performing a surface treatment.

In the above apparatus, the potential control means supplies the plasma beam toward the material evaporation source to form a film.
By applying a bias voltage to the substrate supported by the substrate support device to cause ions in the plasma beam from the plasma source to be incident on this substrate to perform surface treatment,
Simplify gas components etc. chemically adsorbed on the substrate surface before film formation
It can be reliably removed. Therefore, a film having high orientation and favorable electric characteristics can be formed over a clean substrate.

In a preferred embodiment of the above-mentioned device, at least one of the magnet and the coil is arranged in a ring around the hearth and controls a magnetic field above and close to the hearth. An auxiliary anode disposed adjacent and above, wherein the plasma source comprises:
It is a pressure gradient type plasma gun.

In this case, the magnetic field control member corrects the plasma beam incident on the hearth with a cusp-shaped magnetic field or the like, thereby quickly forming a film having a more uniform thickness. Further, the incidence of the plasma beam on the hearth can be controlled using the auxiliary anode.

[0018]

FIG. 1 is a diagram schematically illustrating an entire structure of a film forming apparatus according to an embodiment of the present invention. This film forming apparatus is for forming a metal wiring film, and includes a vacuum chamber 10 serving as a film forming chamber and a plasma gun 3 serving as a plasma source for supplying a plasma beam PB into the vacuum chamber 10.
0, an anode member 50 disposed at the bottom in the vacuum vessel 10 and receiving the plasma beam PB during film formation;
0, a holding mechanism 60 arranged above and holding the substrate W;
A main control device 80 is provided for integrally controlling these operations.

The plasma gun 30 has a plasma beam PB
Is a plasma gun of a pressure gradient type that is generated by a DC arc discharge, and its main body is mounted on a cylindrical portion 12 provided on the side wall of the vacuum vessel 10. The main body is composed of a glass tube 32 whose one end is closed by a cathode 31. In the glass tube 32, a cylinder 33 made of molybdenum Mo is fixed to the cathode 31 and arranged concentrically with the glass tube 32. Inside the cylinder 33, a disk 34 made of LaB ₆ and a tantalum And a pipe 35 made of Ta. The first and second intermediate electrodes 4 are provided between the end of the glass tube 32 opposite to the cathode 31 and the end of the cylindrical portion 12 extending from the vacuum vessel 10.
1, 42 are concentrically arranged in series. One of the first
An annular permanent magnet 44 for converging the plasma beam PB is built in the intermediate electrode 41. An electromagnet coil 45 for converging the plasma beam PB is also built in the second intermediate electrode 42. Around the cylindrical portion 12, the first and second intermediate electrodes 4 generated on the cathode 31 side
A steering coil 47 for guiding the plasma beam PB extracted to 1, 42 into the vacuum vessel 10 is provided in an annular shape.

When the plasma gun 30 is operated, a discharge occurs between the cathode 31 and the hearth 51 in the vacuum vessel 10, and a plasma beam PB is generated. This plasma beam PB reaches the hearth 51 while being guided by a magnetic field determined by the steering coil 47 and the permanent magnet 55 in the auxiliary anode 52.

The operating state of the plasma gun 30 is controlled by a gun driving device 48. This gun drive 4
8 can turn on / off the power supply to the cathode 31 and adjust the voltage supplied thereto, and further supply power to the first and second intermediate electrodes 41 and 42, the electromagnet coil 45, and the steering coil 47. To adjust. The state of the plasma beam PB supplied into the vacuum chamber 10 is controlled by such a gun driving device 48.

It should be noted that the pipe 35 disposed at the innermost side is
Is for introducing a carrier gas such as Ar as a source of the plasma beam PB into the plasma gun 30;
Gas supply source 39 via flow meter 37 and flow control valve 38
It is connected to the. The flow rate of the carrier gas detected by the flow meter 37 is monitored by the main controller 80 and is used for adjusting the flow rate of the carrier gas by the flow rate control valve 38 and the like. An exhaust pump 77 is attached to the side of the vacuum vessel 10 facing the plasma gun 30 via a vacuum gate 76 to reduce the pressure inside the vacuum vessel 10 to a desired pressure.

The anode member 50 disposed in the lower portion of the vacuum vessel 10 includes a hearth 51 which is a main anode for guiding the plasma beam PB downward, and an annular auxiliary anode 52 disposed around the hearth 51.

The former hearth 51 is formed of a conductive material having good thermal conductivity and is supported by a grounded vacuum vessel 10 via an insulator (not shown). The hearth 51 is controlled to an appropriate positive potential by the anode power supply device 58, and draws the plasma beam PB emitted from the plasma gun 30 and guided by the magnetic field downward. The hearth 51 has a hearth body 53 as a crucible-shaped material evaporation source in a concave portion at the upper center where electrons in the plasma beam PB from the plasma gun 30 are incident. Inside the hearth body 53, a metal such as copper, which is a film material, is stored in a molten state.

The latter auxiliary anode 52 is constituted by an annular container arranged concentrically around the hearth 51. In this annular container, an annular permanent magnet 55 made of ferrite or the like and a coil 56 concentrically stacked therewith are housed. The permanent magnet 55 and the coil 56 are magnetic field control members, and form a cusp-shaped magnetic field immediately above the hearth 51. Thereby, the direction and the like of the plasma beam PB incident on the hearth 51 can be corrected.

A coil 56 in the auxiliary anode 52 constitutes an electromagnet, and is supplied with power from an anode power supply 58. In this case, the direction of the magnetic field on the center side of the excited coil 56 is configured to be the same as the magnetic field on the center side generated by the permanent magnet 55. The anode power supply 58 includes a coil 56
Of the plasma beam PB incident on the hearth 51 can be finely adjusted.

The container of the auxiliary anode 52 is also formed of a conductive material having good thermal conductivity, similarly to the hearth 51. The auxiliary anode 52 is attached to the hearth 51 via an insulator not shown. The anode power supply device 58 can control the electric field above the hearth body 53 by changing the voltage applied to the auxiliary anode 52, particularly the auxiliary anode body above the auxiliary anode 52.

A holding mechanism 60 disposed in the upper part of the vacuum vessel 10 includes a substrate holder 61 which is a substrate support device for holding a substrate W with a film-forming surface above the hearth 51, and a substrate holder 61. The substrate W fixed to the upper part of the holder 61
And a temperature adjusting device 62 for adjusting the temperature of the rear surface side. The substrate holder 61 is supplied with power from a substrate power supply device 68, which is a potential control means, in an insulated state with respect to the vacuum vessel 10, and applies the surface of the substrate W to the zero-potential vacuum vessel 10 at an appropriate timing. It is biased to a negative potential or a positive potential, or maintained in a floating state. Temperature controller 62
Is controlled by a temperature control device 69, which supplies power to a heater built in the temperature control device 62 or supplies a cooling medium to a built-in pipe,
The temperature controller 62 and the substrate holder 61 are maintained at a desired temperature.

The operation of the film forming apparatus shown in FIG. 1 will be described below with reference to FIG. First, the substrate W is placed in the vacuum container 10.
And the substrate holder 61 with the film-forming surface facing down.
(Step S1). This substrate W is, for example, S
An SiO ₂ layer having an appropriate pattern is formed on an i-wafer, and a thin barrier film made of TaN or the like is formed on the entire surface of the SiO ₂ layer including holes and grooves.

Next, the film formation surface of the substrate W is cleaned by appropriately operating the plasma gun 30 (step S).
2). In other words, a current of about 40 A is supplied to the cathode 31 by the gun driving device 48 while supplying an appropriate amount of Ar ions from the pipe 35 into the vacuum vessel 10 by the flow control valve 38. In such a state, the potential of the film formation surface of the substrate W is maintained at about 0 to -200 V, preferably about -5 to -100 V, that is, the processing bias voltage by the substrate power supply device 68. Thus, the film formation surface of the substrate W is cleaned. At this time, the temperature of the substrate W can be appropriately adjusted by the temperature adjusting device 62. When the processing bias voltage is higher than −5 V, the surface cleaning effect is not sufficiently obtained, and the adhesion of a metal wiring film to be formed later gradually deteriorates, depending on the type and surface condition of the substrate W. . Conversely, when the processing bias voltage is-
If the voltage is lower than 100 V, the energy of the ions incident on the substrate W increases, and the surface of the substrate W is likely to be gradually damaged.

When Ar gas is used as a carrier as described above, the plasma potential becomes +10 to +20 V. Therefore, when the potential of the film formation surface of the substrate W is set to, for example, −50 V by the substrate power supply device 68, Ar ions collide with the substrate W with energy of about 55 to 65 eV and are adsorbed on the film formation surface of the substrate W. Release atoms.

Gas adsorption is classified into physical adsorption and chemical adsorption. Of these, the gas physically adsorbed on the substrate W is relatively short by heating the substrate W to about 200 to 300 ° C. in a vacuum. Although removable in time, chemisorbed gases are not easily released by overheating alone. For this reason,
By performing cleaning by causing relatively low energy Ar ions to be incident on the film formation surface of the substrate W, gas chemically adsorbed on the film formation surface of the substrate W before film formation is quickly and efficiently removed. And no damage is caused to the film formation surface of the substrate W.

Next, the generation of the plasma beam PB from the plasma gun 30 is increased and supplied to the hearth 51 so that the substrate W
A metal wiring film is formed thereon (Step S3). That is,
The gun drive unit 48 supplies an appropriate amount of Ar ions from the pipe 35 into the vacuum vessel 10 through the flow control valve 38.
A current of about 100 A is supplied to the cathode 31 to form a high-density plasma, and the obtained plasma beam PB is guided to the hearth 51 side. The evaporating substance (film material) stored in the hearth body 53 is heated by the plasma beam PB and emitted from the hearth body 53 as vapor. This vapor is ionized by the plasma beam PB, and the Haas 5
A uniform coating is formed on the surface of the substrate W disposed opposite to the substrate 1. At this time, by appropriately adjusting the temperature of the substrate W by the temperature adjusting device 62, the state of the metal wiring film formed on the substrate W can be controlled to some extent.

By using the above-mentioned plasma gun 30, a strong plasma beam can be continuously and stably supplied, and a high-quality metal wiring film can be quickly formed on the substrate W. . Further, since a cusp magnetic field is formed above the hearth 51 by the permanent magnet 55 and the like, and the plasma beam incident on the hearth 51 is corrected, a film having a more uniform thickness is formed on the substrate W.

In forming such a film, an appropriate negative bias voltage, that is, a control bias voltage can be applied to the substrate W at an appropriate timing. Thus, A
Various films can be formed by using sputtering with r ions, and holes and grooves on the substrate W can be reliably embedded.

When the metal wiring film having a desired thickness is formed on the surface of the substrate W, the operation of the plasma gun 30 is stopped,
The substrate W is carried out of the vacuum container 10 (Step S4).

As described above, on the substrate W, a metal wiring film having good step coverage, hardly forming voids and the like, and having good crystal orientation is formed. For example, in many metal conductive materials having a face-centered cubic lattice, regardless of the surface state (crystallinity, unevenness) of the barrier film, (111)
A film having high orientation can be formed with the surface facing upward. As described above, the metal wiring film having high density and good crystal orientation not only exhibits high conductivity, but also has high resistance to electromigration and can provide high-quality wiring.

FIG. 3 is a graph showing an X-ray diffraction spectrum of the surface of the metal wiring material film obtained in a specific example. This metal wiring film is deposited on a SiO ₂ layer and a TaN layer which are flatly laminated on a Si wafer.

Table 1 below is a diagram for explaining various conditions when forming the metal wiring film of FIG. The surface cleaning performed on the substrate W of the example was performed continuously for 180 seconds at a current supplied to the cathode 31 of the plasma gun 30 of about 40 A and a bias voltage of the substrate W of -65 V. The film formation, which is the main step of the film formation, was performed under the same conditions in the example in which the surface cleaning was performed and the comparative example in which the surface cleaning was not performed. That is,
The current supplied to the cathode 31 of the plasma gun 30 is 100 A
With the bias voltage of the substrate W set to 0 V, a metal wiring material was continuously deposited for 22 minutes. The measurement results of X-ray diffraction show high crystal orientation even without cleaning, but 3 times higher than this when surface cleaning is performed.
More than twice as high (111) crystal orientation.

[Table 1] Although the present invention has been described with reference to the above embodiments, the present invention is not limited to the above embodiments. For example,
In the above embodiment, the surface cleaning is performed while suppressing the evaporation of the film material in the hearth 51 by making the current supplied to the cathode 31 of the plasma gun 30 smaller than during film formation. The surface cleaning can be performed while suppressing evaporation of the film material in the hearth 51 by temporarily guiding the plasma beam PB to the auxiliary anode 52 by adjusting the temperature.

Although the surface cleaning is performed using Ar ions, the surface cleaning may be performed using ions other than Ar ions. Specifically, H, N
e, Kr, Xe, etc. can be used alone or in combination. At this time, an appropriate bias voltage is applied to the substrate W, and 5 to 200 eV, preferably 10 to 100 eV
By making the ions having the above energy incident on the deposition surface, a film obtained in a later step can have high orientation.

In the above embodiment, the surface cleaning with ions is performed before the Cu film is formed.
It goes without saying that the surface cleaning by ions of this embodiment can be used for film formation other than Cu. For example,
Prior to the formation of a metal film such as Au, Ag, Al, or Pt, and further, the formation of a semiconductor film, the plasma is supplied while a bias voltage is applied to the substrate W.
The orientation of Ag, Al, Pt film and the like can be improved.

It has been experimentally confirmed that a sufficient effect can be obtained with a surface cleaning time of several seconds to several minutes using plasma ions. However, various types of film material, substrate type, processing bias voltage and the like can be obtained. It can be set appropriately according to conditions.

A processing position for performing surface cleaning by plasma ions in the vacuum vessel 10 and a hearth 51
Can be separated from a film formation position where a film is formed on the substrate W in the opposite direction. Further, the surface cleaning using plasma ions and the film formation on the substrate W can be performed in separate chambers. However, by performing the surface cleaning and the film formation in the same chamber and using the plasma gun 30 for film formation for the surface cleaning, simpler and more efficient processing can be performed.

[0045]

As is apparent from the above description, in the method of the present invention, in the first step, a predetermined processing bias voltage is applied to the substrate to cause ions in the plasma to be incident on the substrate. , The gas components and the like chemically adsorbed on the surface of the substrate can be easily and reliably removed. Therefore, in the second step, a film having high orientation and good electric characteristics can be formed over a clean substrate.

According to the film forming apparatus of the present invention, the potential control means supplies the bias voltage to the substrate supported by the substrate supporting apparatus before supplying the plasma beam toward the material evaporation source to form the film. Is applied to cause ions in the plasma beam from the plasma source to be incident on this substrate to perform surface treatment, so that gas components and the like chemically adsorbed on the surface of the substrate before film formation can be easily and reliably removed. Can be. Therefore, a film having high orientation and favorable electric characteristics can be formed over a clean substrate.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall structure of a film forming apparatus according to an embodiment.

FIG. 2 is a diagram conceptually illustrating a film forming method according to an embodiment.

FIG. 3 is a diagram illustrating characteristics of an obtained film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum container 30 Plasma gun 39 Gas supply source 47 Steering coil 48 Gun drive device 50 Anode member 51 Hearth 52 Auxiliary anode 58 Anode power supply device 60 Holding mechanism 61 Substrate holder 62 Temperature control device 68 Substrate power supply device 69 Temperature control device 77 Exhaust gas Pump 80 Main controller

Continued on the front page F term (reference) 4K029 BA04 BA05 BA08 BA13 CA03 CA13 DD05 EA05 EA09 FA04 FA05 4M104 AA01 BB32 CC01 DD22 DD36 DD38 DD39 5F103 AA02 AA06 DD28 HH03 HH04 HH05 HH10 PP01

Claims (6)

[Claims] A first step of applying a predetermined processing bias voltage to the substrate to cause ions in plasma to be incident on the substrate and performing a surface treatment on the substrate; and a film forming chamber after the first step. Supplying a plasma beam toward a material evaporation source disposed therein, thereby evaporating a film material of the material evaporation source and attaching the film material to a surface of the substrate. 2. The film forming method according to claim 1, further comprising a step of controlling the progress of film formation by applying a predetermined control bias voltage to said substrate during said second step. 3. The method according to claim 1, wherein the ions are Ar, H, He, Ne,
2. The film forming method according to claim 1, wherein the method includes at least one of Kr and Xe and has an energy of 5 to 200 eV. 4. The method according to claim 2, wherein in the second step, the plasma beam is supplied from the pressure gradient plasma gun toward the hearth while controlling a magnetic field above and close to the hearth holding the material evaporation source. The film forming apparatus according to claim 1, wherein: 5. A hearth which has a plasma source for supplying a plasma beam into a film formation chamber, a material evaporation source capable of containing a film material, and is arranged in the film formation chamber to guide the plasma beam; A substrate support device that supports the substrate in the film formation chamber so as to face the hearth, and is supported by the substrate support device before the plasma beam is supplied toward the material evaporation source and film formation is performed. And a potential control means for applying ions in a plasma beam from the plasma source to the substrate by applying a bias voltage to the substrate to perform surface treatment. 6. A magnetic field control member having at least one of a magnet and a coil disposed annularly around the hearth and controlling a magnetic field above and close to the hearth, and disposed near and above the magnetic field control member. 6. The film forming apparatus according to claim 5, further comprising an auxiliary anode to be formed, wherein the plasma source is a pressure gradient type plasma gun.