JP2001295031A - Method and apparatus for film deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for film deposition by which a film having the sufficient thickness is deposited on a sidewall of a groove and a hole. SOLUTION: An evaporated substance heated by a plasma beam PB and emitted from a hearth body 53 is ionized by the plasma beam PB, passed through a mesh electrode 80 and deposited on a lower side of a substrate W to form the film. If the suitable voltage is applied to the mesh electrode 80, the evaporated substance introduced in the substrate W can be deflected by the mesh electrode 80 immediately before it is made incident, and the evaporated substance can be uniformly made incident on the substrate W in the distribution of various angular components. This means, even if a shade is formed on the groove or the hole when a hearth 51 is a point-like evaporation source and a straight-moving evaporated substance advances straight, a film having the sufficient thickness similar to that on the periphery thereof can be deposited on the sidewall of the very small groove or the hole formed on the substrate W by means of a simple and space-saved mesh electrode 80.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus and method for forming a conductive film or the like by using a plasma beam, and more particularly, to a method for forming a seed layer to be an electrode in electrolytic plating for forming wiring of a semiconductor device. The present invention relates to an apparatus and a method for forming a film.

[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 on the hearth is evaporated and ionized.
2. Description of the Related Art There is known an ion plating apparatus that adheres an ionized deposition material to a surface of a substrate arranged opposite to a hearth.

[0003] Japanese Patent Application Laid-Open No. 7-138743 discloses an ion plating apparatus of this kind, in which an incident beam direction adjusting means comprising a permanent magnet or the like concentrically arranged around the hearth is incorporated, thereby increasing the incidence surface of the hearth. Which forms a cusp magnetic field is disclosed. In this ion plating apparatus, the plasma beam incident on the hearth is corrected by the cusp magnetic field formed above the hearth, and the plasma beam is linearly incident from directly above the hearth, so that the evaporated substance in the hearth is uniformly heated. In addition, the thickness of the film formed on the surface of the substrate can be made relatively uniform.

Further, in the above-described film forming apparatus,
A plurality of hearths serving as evaporation sources are prepared to eliminate the positional dependence on the incident direction of the evaporation particles on the substrate, so that a more uniform film formation on the substrate is possible. As another method, a uniform film formation on the substrate can be achieved by causing the substrate to make an in-plane motion typified by planetary motion to eliminate the position dependence of the incident direction of the evaporated particles on the substrate. Some ideas have been made to make it possible.

[0005]

However, in the above-described film forming apparatus, the structure of the apparatus is complicated by incorporating a plurality of hearths or means for moving the substrate in-plane, and the entire apparatus is enlarged. .

In a substrate having a fine structure such as a groove or a hole, even if a uniform film can be formed around the groove or the hole, the side wall of all the grooves and the holes distributed on the substrate is uneven. It is impossible to form a film with a sufficient thickness.

Accordingly, an object of the present invention is to provide a film forming apparatus and a method capable of forming a film having a sufficient thickness without unevenness on a substrate having a fine structure by a simple and small apparatus. .

[0008]

In order to solve the above-mentioned problems, a film forming apparatus according to the present invention comprises a plasma source for supplying a plasma beam into a film forming chamber, a plasma source arranged in the film forming chamber, and a plasma beam. A hearth having a material evaporation source capable of accommodating a metal as a film material, a support member for supporting a substrate on which a film is to be formed facing the hearth in a film formation chamber, and a substrate supported by the support member. On the hearth side of a film forming position corresponding to the film forming surface, a mesh-shaped deflection electrode is two-dimensionally arranged close to the film forming position.

In the above apparatus, a mesh-shaped deflection electrode is provided on the hearth side of a film formation position corresponding to the film formation surface of the substrate supported by the support member and is two-dimensionally arranged close to the film formation position. Therefore, by applying an appropriate voltage to this deflection electrode, a sheath electric field is formed along the deflection electrode,
As a whole, an electric field can be formed near the film formation position. Thereby, the path of the charged particles of the film material, which is ionized by the plasma beam during the film formation and enters the film formation surface of the substrate, can be deflected with an appropriate distribution, and the particles of the film material can be deflected at an angle perpendicular to the substrate. The light can be incident on the substrate with a distribution of various angular components as well as the components. That is, the side walls of the grooves and holes formed in the substrate can be formed with a sufficient thickness similarly to the periphery of these grooves and holes by the simple and space-saving deflection electrode.

In a preferred aspect of the above-described apparatus, the apparatus further comprises a voltage application device for applying a negative voltage to the deflection electrode with respect to the plasma. In this case, the evaporated particles of the film material having a positive charge in the plasma are effectively deflected and enter the substrate, so that the film can be reliably formed on the side walls such as the grooves and holes.

In a preferred embodiment of the above-mentioned device, an AC voltage is applied to the deflection electrode. In this case, the amount of deflection of the evaporated particles of the film material by the deflection electrode, that is, the angle of incidence on the substrate fluctuates with time, so that a uniform film can be formed on the side walls such as grooves and holes.

In a preferred embodiment of the above-mentioned apparatus, the deflection electrode is formed of a film forming material. In this case, even if the deflection electrode is sputtered by evaporating particles or the like of the film material, no impurity is generated, so that a film with higher purity can be formed.

In a preferred embodiment of the above-mentioned apparatus, the apparatus further comprises a magnet arranged annularly around the hearth, or a magnetic field control member comprising a magnet and a coil for controlling a magnetic field above and close to the hearth, 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, so that a film having a more uniform thickness can be formed.

Further, according to the film forming method of the present invention, a metal as a film material is evaporated from a material evaporation source while supplying a plasma beam toward a material evaporation source arranged as an anode in a film forming chamber. A film-forming method for adhering to a surface of a substrate disposed in a film chamber opposite to a material evaporation source, and two-dimensionally close to the film-forming surface on a material evaporation source side of the film-forming surface of the substrate. An electric field is formed in the vicinity of the film formation surface by the arranged mesh-shaped deflection electrodes.

In the above method, an electric field is formed in the vicinity of the film formation surface by a mesh-shaped deflection electrode that is two-dimensionally arranged near the film formation surface on the material evaporation source side of the film formation surface of the substrate. During film formation, the path of the charged particles of the film material that is ionized by the plasma beam and incident on the film formation surface of the substrate can be deflected with an appropriate distribution, and the particles of the film material can be deflected only by the angle component perpendicular to the substrate. And can be incident on the substrate with various distributions of angle components. That is, the side walls of the grooves and holes formed in the substrate can be formed with a sufficient thickness similarly to the periphery of these grooves and holes by the simple and space-saving deflection electrode.

[0016]

FIG. 1 is a diagram schematically illustrating the entire structure of a film forming apparatus according to an embodiment. This film forming apparatus
A vacuum vessel 10 serving as a film forming chamber, a plasma gun 30 serving as a plasma source for supplying a plasma beam PB into the vacuum vessel 10, and an anode member arranged at the bottom of the vacuum vessel 10 to control the flow of the plasma beam PB 50 and vacuum vessel 1
0, a holding mechanism 60 arranged above and holding the substrate W;
A mesh electrode 80 is disposed near the holding mechanism 60 and deflects the course of the evaporating particles incident on the substrate W, and a main control device 90 for controlling these operations in an integrated manner.

The plasma gun 30 is a pressure gradient type plasma gun that generates a plasma beam PB by using a DC arc discharge. The main body of the plasma gun 30 is attached to the cylindrical portion 12 provided on the side wall of the vacuum vessel 10 as will be described later. A pair of intermediate electrodes 41,
42. This body part is the cathode 3
1 comprises a glass tube 32 one end of which is closed. In the glass tube 32, a cylinder 3 made of molybdenum Mo
3 is fixed to the cathode 31 and arranged concentrically. Inside the cylinder 33, a disk 34 made of LaB ₆ and a pipe 35 made of tantalum Ta are incorporated. A pair of intermediate electrodes 41 and 42 provided between the glass tube 32 and the cylindrical portion 12 are coaxially arranged in series with the glass tube 32 and the cylindrical portion 12. One first intermediate electrode 41
An annular permanent magnet 44 for converging the plasma beam PB is built therein. An electromagnet coil 45 for converging the plasma beam PB is also built in the other second intermediate electrode 42. In addition, around the cylindrical part 12, the first and second intermediate electrodes 41 generated on the cathode 31 side,
The plasma beam PB extracted up to 42
A steering coil 47 for guiding the inside of the steering coil 0 is provided.

The operation of the plasma gun 30 is controlled by a gun driving device 48. This gun driving device 48
Can turn on / off the power supply to the cathode 31 and adjust the supply voltage to the cathode 31, and further supply the power to the first and second intermediate electrodes 41 and 42, the electromagnet coil 45, and the steering coil 47. 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 90 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 mounted on a side surface 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 an appropriate pressure.

The anode member 50 disposed in the lower portion of the vacuum vessel 10 includes a hearth 51 as 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 sucks the plasma beam PB emitted from the plasma gun 30 downward. The hearth 51 is
A hearth body 53 serving as a crucible-shaped material evaporation source is provided in the formed concave portion at the upper center where the plasma beam PB from the plasma gun 30 is 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. The annular container accommodates an annular permanent magnet 55 made of ferrite or the like and a coil 56 concentrically laminated therewith. 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 made 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 auxiliary control the electric field above the hearth body 53 by changing the voltage applied to the auxiliary anode 52. That is, by giving an appropriate potential to the auxiliary anode 52 at an appropriate timing, the switching control for switching the supply of the plasma beam PB from the hearth body 53 to the auxiliary anode 52 or, conversely, switching from the auxiliary anode 52 to the hearth body 53 is performed. It becomes possible at any timing.

The holding mechanism 60 disposed at the upper part in the vacuum vessel 10 has a substrate holder 6 serving as a support member for holding the substrate W with the film-forming surface being lower above the hearth 51.
1 and a temperature control device 62 fixed to the upper portion of the substrate holder 61 to control the temperature of the substrate W from the back side. The substrate holder 61 is supplied with power from the potential setting device 68 in a state insulated from the vacuum vessel 10 and is biased to an appropriate potential with respect to the zero-potential vacuum vessel 10.
The temperature control device 62 is controlled by a temperature control device 69. The temperature control device 69 supplies power to a heater built in the temperature control device 62 or supplies a cooling medium to a built-in pipe to control the temperature. The device 62 and the substrate holder 61 are maintained at a desired temperature.

Below the film formation surface of the substrate W supported by the holding mechanism 60, that is, below the hearth 51, a mesh electrode 80 as a deflection electrode is two-dimensionally arranged close to the film formation surface. The mesh electrode 80 is supplied with power from the potential setting device 68 in a state insulated from the vacuum vessel 10 and is biased to an appropriate potential with respect to the plasma.
A two-dimensional electric field that fluctuates spatially periodically is formed in the vicinity of the film-forming surface. Accordingly, the path of charged particles such as Cu ions emitted from the hearth body 53 and incident on the film formation surface of the substrate W can be deflected with an appropriate distribution, and the film material particles such as Cu can be deflected with respect to the substrate W. Light can be incident with distributions of various angle components. Therefore, even when a fine structure such as a groove or a hole is formed in the substrate W, a film having a sufficient thickness can be formed on the side wall, the slope, and the like, similarly to the top.
Note that the bias voltage applied to the mesh electrode 80 is set to be a minus potential with respect to the plasma potential in consideration that charged particles incident on the film formation surface are usually positive ions. Such a bias voltage may be a DC bias or a bias including an AC component.

The operation of the film forming apparatus shown in FIG. 1 will be described below. In this film forming apparatus, a discharge is generated between the cathode 31 of the plasma gun 30 and the hearth 51 in the vacuum vessel 10, thereby generating a plasma beam PB. 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 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 an evaporating substance. This evaporant is ionized by the plasma beam PB, passes through the mesh electrode 80, and adheres to the lower surface of the substrate W to form a film. At this time, if an appropriate voltage is applied to the mesh electrode 80, the evaporating substance incident on the substrate W can be deflected by the mesh electrode 80 immediately before incidence, and the evaporating substance can be uniformly distributed with various angular component distributions. W can be incident. In other words, even when the hearth 51 is a point-like evaporation source and the evaporation material from there goes straight, a shadow is formed in a groove or a hole on the substrate W. Accordingly, the side wall of the fine groove or hole formed on the substrate W can be formed with a sufficient thickness similarly to the periphery thereof.

The conductive film such as Cu formed on the substrate W is used as a seed layer for electroplating. That is, the seed layer thus formed is used as an electrode for Cu
By performing such electroplating, the grooves and holes formed on the substrate W are filled with Cu or the like, and a wiring layer made of Cu or the like can be formed on the entire surface of the substrate W. At this time, since the seed layer is formed by the film forming apparatus of the present embodiment,
The grooves and holes on the substrate W are conformally covered.
Therefore, when such a seed layer is used as an electrode for electroplating, it is possible to suppress generation of voids and obtain a wiring with good adhesion.

FIG. 2 is a diagram illustrating the structure and operation of the mesh electrode 80. Here, FIG. 2A is a plan view showing a part of the mesh electrode 80, and FIG.
It is an enlarged view of the mesh electrode 80 of (a).

The mesh electrodes 80 extend in the AB direction and are arranged at equal intervals in the CD direction orthogonal to the first direction. The mesh electrodes 80 are arranged at regular intervals in the AB direction orthogonal to the first group of interconnects 80a. And a second group of wirings 80b. The mesh interval between the wirings 80a and 80b is appropriately set according to the density of the plasma and the like, but can be, for example, in a range of about 0.5 to 5 mm, and preferably about 1 to 3 mm. Can be effectively deflected.

When a voltage different from the surrounding plasma potential is applied to the mesh electrode 80, the wirings 80a, 80a
A sheath S is formed around b. The width of the sheath S varies depending on the surrounding plasma density and the voltage applied to the mesh electrode 80. For example, when the plasma density increases, the width of the sheath S decreases. In this case, it is necessary to reduce the mesh interval to some extent. To be more specific, the electron temperature is 3 eV, 10 ¹⁰ electrons / cm ³
At a plasma density of about -30 to 40 V with respect to the plasma potential at the mesh electrode 80, the thickness of the sheath S is 0.5 mm with respect to the diameter of the mesh wire of 1 mm.
About. In this case, the mesh interval needs to be about 1 to 2 mm.

The thickness of each of the wirings 80a and 80b is desirably as thin as possible from the viewpoint of not blocking the ions of the evaporating substance, but is not less than a certain value from the viewpoint of preventing the occurrence of bending or the like due to thermal expansion or the like. Needs thickness. Typically, the thickness of each wiring 80a, 80b is 0.2 to 0.5
mm.

The material of the wirings 80a and 80b is the same as the material to be evaporated. For example, if the film material is Cu, Ag, Au, Pt
Etc., the material of each wiring 80a, 80b is also Cu, A
g, Au, Pt, etc. Each wiring 80a, 80b
It is not impossible to use stainless steel or the like as the material for the above, but if stainless steel or the like is sputtered by the ions of the evaporating substance, impurities are mixed, which is not desirable.

The bias voltage applied to the mesh electrode 80 is set to, for example, a negative potential with respect to the plasma potential in consideration of the fact that the evaporating substance incident on the film-forming surface of the substrate W is usually a positive ion. I do. Such a potential difference accelerates the positive ions that have entered the sheath S once, and changes the traveling direction to emit the positive ions outside the sheath S. In addition,
When the bias voltage is set to be a positive potential with respect to the plasma potential, the possibility that the evaporated substance ions are repelled by the mesh electrode 80 is increased. Further, even if the bias voltage is a minus potential with respect to the plasma potential, if the absolute value is too large, the mesh electrode 80 is sputtered, and in some cases, the film formation layer on the substrate W is also sputtered. Therefore, the bias voltage applied to the mesh electrode 80 is set to about 100 V or less. here,
The plasma potential is, for example, about 40 eV or less. The absolute value of the bias voltage with respect to the plasma potential is about 60V. The absolute value of the bias voltage as described above may be a DC bias, a high-frequency AC bias, or a bias including a high-frequency AC component. When an AC bias is used, its effective value is DC
This is an object to be compared with the case where a bias is applied.

When a bias containing a high-frequency AC component or a high-frequency AC bias is applied to the mesh electrode 80, the incident angle of the evaporated substance ions to the substrate W fluctuates with time. That is, the direction of the evaporating substance ions can be modulated at high speed over time, and a more uniform film can be formed in the holes and grooves on the substrate W.

There is no particular limitation on the potential of the substrate W itself.
This is undesirable because the film formation surface of the substrate W is sputtered. As the potential of the substrate W, for example, about 0 to −60 V is practically used.

FIG. 3 is a diagram for explaining the state of the evaporated substance ions incident on the substrate W. FIG. 3A is a side view of the substrate W and the mesh electrode 80, and FIG. 3B is an enlarged side view showing a part of the mesh electrode 80. FIG.
As is clear from (a), the evaporating substance ion EI that has traveled straight to the mesh electrode 80 is deflected with an appropriate distribution when passing through the sheath S of the mesh electrode 80, and is formed on the lower surface of the substrate W. The light enters the concave portion RE formed at the film position PP and the periphery thereof. Of the evaporating substance ions EI, those incident on the substrate W at a certain angle inclined from the vertical axis are incident on the side wall of the concave portion RE and adhere thereto. That is, a uniform film can be formed to some extent on the side wall of the concave portion RE.

As shown in FIG. 3A, the mesh electrode 8
It can be seen that the variation of the incident angle of the evaporant ion EI due to 0 becomes larger as the evaporant ion EI is incident closer to the wiring 80b. Although not shown, in a cross section orthogonal to this, the evaporation substance ions EI
The closer the angle is, the larger the amount of angle variation becomes.

The mesh electrode 80 and the film forming position P on the substrate W
The distance from P is set so that the mesh electrode 80 does not form a shadow. Although depending on other conditions, for example, when the distance between the two is 1 mm or more, the formation of shadow can be almost certainly prevented.

[0040]

As is apparent from the above description, according to the film forming apparatus of the present invention, the film forming position is located on the hearth side of the film forming position corresponding to the film forming surface of the substrate supported by the support member. Since a mesh-shaped deflecting electrode arranged two-dimensionally close to each other is provided, a sheath electric field is formed along the deflecting electrode by applying an appropriate voltage to the deflecting electrode, and as a whole, a film forming position is formed. An electric field can be formed in the vicinity of.
Thereby, the path of the charged particles of the film material, which is ionized by the plasma beam during the film formation and enters the film formation surface of the substrate, can be deflected with an appropriate distribution, and the particles of the film material can be deflected at an angle perpendicular to the substrate. The light can be incident on the substrate with a distribution of various angular components as well as the components. That is,
With a simple and space-saving deflection electrode, the side walls of the grooves and holes formed on the substrate can be formed with a sufficient thickness similarly to the periphery of these grooves and holes.

According to the film forming method of the present invention, the film forming surface is formed on the film forming surface of the substrate by a mesh-shaped deflection electrode two-dimensionally arranged close to the film forming surface on the material evaporation source side. Since an electric field is formed in the vicinity, the path of the charged particles of the film material, which is ionized by the plasma beam during the film formation and enters the film formation surface of the substrate, can be deflected with an appropriate distribution,
Particles of the film material can be incident on the substrate with various angular component distributions as well as an angular component perpendicular to the substrate. In other words, with a simple and space-saving deflection electrode,
The side wall of the groove or hole formed in the substrate can be formed with a sufficient thickness similarly to the periphery of the groove or hole.

[Brief description of the drawings]

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

FIGS. 2 (a) and 2 (b) are a plan view and an enlarged view illustrating a mesh electrode incorporated in the apparatus of FIG.

FIGS. 3 (a) and 3 (b) are a side view and an enlarged view illustrating a mesh electrode incorporated in the apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum container 30 Plasma gun 39 Gas supply source 41,42 Intermediate electrode 47 Steering coil 48 Gun drive device 50 Anode member 51 Hearth 52 Auxiliary anode 53 Hearth body 55 Permanent magnet 56 Coil 58 Anode power supply 60 Holding mechanism 61 Substrate holder 62 Temperature Regulator 68 Substrate power supply 69 Temperature control controller 77 Exhaust pump 80 Mesh electrode 90 Main controller PB Plasma beam W Substrate

Claims (6)

[Claims] 1. A hearth having a plasma source for supplying a plasma beam into a film formation chamber, and a material evaporation source arranged in the film formation chamber for guiding the plasma beam and capable of containing a metal film material. A support member that supports a substrate to be formed into the film formation chamber in opposition to the hearth, and a support member that is supported by the support member and has a film formation position corresponding to the film formation surface on the hearth side. And a mesh-shaped deflection electrode that is two-dimensionally arranged close to the film formation position. 2. The film forming apparatus according to claim 1, further comprising a voltage applying device for applying a negative voltage to said deflection electrode to said plasma. 3. The film forming apparatus according to claim 1, wherein an AC voltage is applied to the deflection electrode. 4. The film forming apparatus according to claim 1, wherein the deflection electrode is formed of the film forming material. 5. A magnetic field control member, comprising a magnet or a magnet and a coil arranged annularly around the hearth, for controlling a magnetic field above and close to the hearth, wherein the plasma source is a pressure gradient type. The film forming apparatus according to claim 1, wherein the apparatus is a plasma gun. 6. A method according to claim 6, wherein a metal as a film material is evaporated from the material evaporation source while supplying a plasma beam toward a material evaporation source disposed as an anode in the film formation chamber. A film-forming method for attaching to a surface of a substrate arranged opposite to a source, wherein the mesh-like shape is two-dimensionally arranged close to the film-forming surface on the material evaporation source side of the film-forming surface of the substrate. Forming an electric field in the vicinity of the film formation surface by the deflection electrode.