JP3486494B2 - Electromagnetic induction type embedding method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric field induction type embedding treatment method and apparatus for performing heating and pressurization required for a semiconductor surface in a hole filling operation which is a step required for semiconductor manufacturing. It is possible to perform an embedding process in a vacuum by connecting to another work process in a vacuum, for example, spattering or coating.

[0002]

2. Description of the Related Art For example, when aluminum metal is used as a metal layer on a wafer, a method of heating the aluminum metal layer for reflow and melting the aluminum metal layer in a hole existing on the wafer surface by gravity is conventionally adopted. Was,
Recently, to prevent the formation of voids as the depth of the hole becomes deeper than the diameter of the hole and the so-called aspect ratio increases, it is moved from a vacuum to an inert gas of several hundred atmospheric pressure and embedded by gas pressure. Methods have come to be used. However, what is originally required for pressure embedding is the surface pressure on the surface of the substrate to be pressed, and it is completely unnecessary except for the substrate surface. Therefore, this method using a gas pressure of several hundreds of atmospheres uses extra energy because it fills an unnecessary space other than the space immediately above the wafer requiring processing with a high-pressure gas. It requires special handling techniques, is subject to strict regulations for safety, and is always exposed to the danger of explosion, and in fact, it is reported that the damage at the time of explosion is great.

[0003]

In the present invention, unlike the conventional heating and pressurizing method, no treatment is carried out at several hundred atmospheric pressure, and therefore, the explosion is caused by being released from the danger of working under high pressure. In addition to resolving the danger of, the high pressure gas stopped filling unnecessary spaces other than the space directly above the wafer requiring hole filling, and several hundred atmospheric pressure was used in the vacuum process such as sputtering and etching. It aims to solve the drawbacks that require various checkpoints in production control by inserting different processes such as processing work.

Therefore, it is an object of the present invention to provide an embedding processing method and apparatus capable of safely and efficiently filling the surface of a substrate by generating only the surface pressure required for the filling. Is. That is, the present inventor notices that the electromagnetic induction from the outside does not reach a depth greater than the thickness of the skin due to the skin effect on the metal surface, during which the skin current flows within the thickness of the skin and the inside of the metal. Since the magnetic field that does not reach the maximum is repelled to the outside, the increase of the magnetic pressure from the outside of the surface layer due to the repelled magnetic field and the heating of the skin layer due to the Joule heat of the skin current are used for this embedding process. This is the basic concept of the invention.

Generally, the depth of the skin effect on the electromagnetic induction of the metal layer is 1/2 of the conductivity, the permeability and the frequency, respectively.
Inversely proportional to the square. Therefore, if the material is determined, the conductivity and magnetic permeability are fixed, and the depth of the skin effect is determined by the fluctuating frequency of the applied high frequency electromagnetic field. This also applies to a vibration frequency when a mechanical oscillator including an ultrasonic wave is applied to a mechanical oscillator including a magnet and an ultrasonic wave.

[0006]

In order to achieve the above-mentioned object, the electromagnetic induction type embedding processing method according to the present invention generates a high frequency magnetic field covering at least a part of the metal layer surface of a wafer, Induces eddy currents in the metal layer,
This eddy current heats at least part of the metal layer surface of the wafer to a temperature at which it softens or fluidizes, and
The feature is that the metal layer is pressed and embedded by the interaction between the applied high-frequency magnetic field and the eddy current.

According to another feature of the present invention, an apparatus for performing the above-mentioned electromagnetic induction type embedding processing method is arranged in parallel in the vicinity of a metal layer surface of a wafer, and at least a part of the metal layer surface of the wafer is arranged. An eddy current induced in a metal layer, which is composed of a high-frequency magnetic field generating means having at least one high-frequency coil for generating a high-frequency magnetic field in a covering form, and a high-frequency power source for energizing the high-frequency magnetic field generating means for generating the high-frequency magnetic field. By this, at least a part of the surface of the metal layer of the wafer is heated to a temperature at which it is softened or fluidized, and the metal layer is pressed by magnetic pressure to be embedded. Further, a control device for setting the frequency and current value of the high frequency current supplied from the high frequency power supply to the high frequency magnetic field generating means may be provided.

The high-frequency magnetic field generating means can be constructed so as to form a high-frequency magnetic field by flowing a high-frequency current in a plane (element surface) parallel to the metal surface layer very near the surface of the wafer, for example, immediately above the metal surface layer such as aluminum. . At that time, it is important for the way of wiring in the plane of the conducting wire through which the high-frequency current is passed that the high-frequency current is allowed to flow to effectively form a magnetic field between the high-frequency magnetic field generating means and the surface of the metal layer. That is, the way of wiring can be appropriately selected according to the purpose, such as a spiral shape, a grid shape, a comb shape, a radial shape on the element surface,
In the selection, it is necessary to improve the magnetic field pressurization and the skin current Joule heating effect caused by the high frequency current by making the parallel distance between the device surface and the metal surface layer on the wafer as narrow as possible. is there.

According to still another feature of the present invention, an apparatus for performing the electromagnetic induction-type embedding processing method is arranged in parallel in the vicinity of the metal layer surface of the wafer, and at least a part of the metal layer surface of the wafer. A vortex induced in the metal layer, which is composed of a high-frequency magnetic field generating means having a plurality of magnets for generating a high-frequency magnetic field covering the slab and a high-frequency vibration generating element for vibrating the high-frequency magnetic field generating means for generating the high-frequency magnetic field. The electric current heats at least a part of the metal layer surface of the wafer to a temperature at which the metal layer is softened or fluidized, and the metal layer is pressed by magnetic pressure to be embedded. In addition to the above configuration, a control device for setting the frequency and magnitude of the vibration supplied from the high frequency vibration generating element to the high frequency magnetic field generating means may be provided. The high-frequency magnetic field generating means is configured to form a high-frequency magnetic field by placing a magnet on a wafer, for example, in a plane (element surface) parallel to the metal surface layer immediately above the metal surface layer such as aluminum, and in the vicinity of the metal and vibrating the magnet. You can also do it. At that time, it is effective to increase the frequency that can be achieved. Therefore, it is desirable that the attached magnet be as light as possible. On the other hand, since the magnet has a static magnetic field inside and around it, there is a possibility of magnetizing the entire wafer by placing it on the wafer, and in order to avoid this, the gradient of the magnetic field strength in the plane direction is extremely steep ( That is, the magnetic field of the magnet is strongly attenuated when it is separated from the element surface). That is, a large number of minute magnets are uniformly arranged on the element surface so that the magnetic lines of force between the NSs are connected as close as possible, or the circular element surface has a width in the radial direction. It is possible to adopt a configuration in which a plurality of concentric circles are separated and ring-shaped magnets having different polarities are installed in mutually adjacent regions.

In the case of heating by using the eddy current on the surface of the metal conductor generated by electromagnetic induction, in principle, when the metal conductor is heated by Joule heat of the eddy current, the eddy current is attenuated at the same time. Since the magnetic pressure on the metal surface is reduced, it is preferable to heat the metal layer on the wafer surface to a temperature at which the plastic change easily occurs by lamp heating or conductive resistance heating immediately before the filling process. Conductive resistance heating means can be provided.

On the other hand, in the case of generating a magnetic pressure using a high frequency vibration generating element, the generated magnetic pressure is not a complete static magnetic field but is accompanied by pulsation, so that mechanical vibration may be generated in the magnetic field generating means and the wafer. Therefore, in order to avoid this, it is desirable to grasp the natural frequencies of the wafer and the magnetic field generation element in advance and to incorporate a means for rapidly absorbing and blocking the generated mechanical vibration into the apparatus.

[0012]

In the electromagnetic induction type embedding processing apparatus according to the present invention having the above-described structure, the high frequency magnetic field generating means is provided parallel to the vicinity of the metal layer on the wafer surface to induce an eddy current in the metal layer on the wafer surface. , The surface metal for securing and press-fitting, which is the most central issue in the hole filling process, by heating the metal layer on the wafer surface and pressurizing by interaction (magnetic pressure) between the high frequency magnetic field and the eddy current. Therefore, it becomes possible to implement the hole filling process by using the vacuum chamber system as in the case of various kinds of processing in high vacuum such as sputtering and etching.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically illustrates an electromagnetic induction embedded processing apparatus embodying the present invention. In the figure, 1 is a vacuum chamber, and 2 is an exhaust port connected to a vacuum pump (not shown). Reference numeral 3 is a used gas introduction port, 4 is a substrate stand in which a heating resistor 5 is incorporated, and the heating resistor 5 is connected to a heating power source 6. A wafer 7 to be processed is mounted on the substrate stand 4. Further, 8 is a high frequency magnetic field generating means, which is positioned immediately above the wafer 7 as shown in the drawing,
It is supported by a rod 9. As shown in FIGS. 2 to 5, the high-frequency magnetic field generating means 8 is configured as a high-frequency coil by wiring conductors in a spiral shape, a grid shape, a comb shape, a radial shape, etc. on a plane, and is connected to a coaxial cable forming a rod 9. Whichever shape is selected, the parallel distance between the plane of the planar high-frequency magnetic field generating means 8 and the metal surface layer on the wafer 7 should be as narrow as possible so that a high-frequency current is generated. To improve the magnetic field pressurization and skin current Joule heating effects. Instead of the high-frequency coil, the high-frequency magnetic field generating means 8 has a large number of minute magnets uniformly arranged on the element surface so as to connect the magnetic lines of force between the NSs as close as possible, as shown in FIG. 7, a circular element surface is divided into a plurality of concentric circles having a width in the radial direction as shown in FIG. 7, and magnets having a circular slice shape with different polarities are provided in mutually adjacent regions, It can also be composed of a magnet. When the high-frequency magnetic field generating means 8 is composed of a high-frequency coil, the high-frequency magnetic field generating means 8 is connected to the high-frequency power source 10 via the rod 9. In this case, the material of the surface of the metal layer of the wafer and the thickness of the metal layer are The high frequency power supply 10 may be provided with a control device 10a capable of automatically setting the frequency and the current value of the high frequency current flowing through the high frequency coil when the designation is made. On the other hand, when the high-frequency magnetic field generating means 8 is composed of a magnet, it is similarly connected to the ultrasonic generator 11 via the rod 9.
In that case, when the material of the surface of the metal layer of the wafer and the thickness of the metal layer are designated, the control device 11a that can automatically set the frequency and magnitude of the vibration applied to the vibrator is the ultrasonic generator 1
Can be provided in 1. In FIG. 1, reference numeral 12 is a mechanical vibration transmission breaker. By the way, in the present invention, the surface pressure of the metal layer on the wafer surface is applied by the magnetic pressure generated or increased in the narrow parallel space, and at the same time, the metal layer is heated. It should be big enough.

As an example, an aluminum metal layer was formed on a Si wafer having a diameter of 1 inch "and a diameter of 2 inches, and the aluminum metal layer was filled in a hole having an aspect ratio of 3 formed on the Si wafer. As the magnetic field generating means 8, a spiral coil and a large number of pebble-shaped magnets laid in a disk are fixed while confirming the adjacent polarities, and a high-frequency current of 13.56 MHz is applied to the spiral coil.
In the case of a large number of pebble magnet discs, ultrasonic vibration of 1 MHz was applied to the center of the disc through a rod. The degree of vacuum is 10 ^-7 mTorr. The surface of the aluminum metal layer is heated to about 600 ° C. by conduction heating, and the magnetic pressure applied to the surface of the aluminum metal layer by the high-frequency magnetic field generating means 8 or the increase of the magnetic pressure was several atmospheric pressure, but the aluminum having an aspect ratio of 3 was used. It was confirmed by a cross-sectional SEM photograph that the holes were filled up cleanly.

[0015]

As described above, according to the present invention, the high frequency magnetic field generating means is provided in parallel with the metal layer on the wafer surface to induce an eddy current in the metal layer on the wafer surface, and the metal layer on the wafer surface is formed. At the same time as heating, the hole filling process is performed by pressurization by the interaction (magnetic pressure) of the high frequency magnetic field and the eddy current. It is possible to perform hole filling processing on the surface of the wafer metal layer in the vacuum chamber without using the step of using.

[Brief description of drawings]

FIG. 1 is a schematic view showing an electromagnetic induction type embedding processing apparatus embodying the present invention.

FIG. 2A is a plan view showing an embodiment of a high frequency magnetic field generating means in the device of the present invention. (B) is a side view.

FIG. 3A is a plan view showing a modification of the high-frequency magnetic field generating means in the device of the present invention. (B) is a side view.

FIG. 4A is a plan view showing another modification of the high-frequency magnetic field generating means in the device of the present invention. (B) is a side view.

FIG. 5A is a plan view showing still another modification of the high-frequency magnetic field generating means in the device of the present invention. (B) is a side view.

FIG. 6A is a plan view showing another embodiment of the high frequency magnetic field generating means in the device of the present invention. (B) is a side view.

FIG. 7A is a plan view showing a modification of another embodiment of the high-frequency magnetic field generating means in the device of the present invention. (B) is a side view.

[Explanation of symbols]

1: Vacuum chamber 2: Exhaust hole 3: Used gas inlet 4: Board stand 5: Resistance for heating 6: Power supply for heating 7: Wafer 8: High frequency magnetic field generating means 9: Rod 10: High frequency power supply 11: Ultrasonic generator

Claims (5)

(57) [Claims] 1. An eddy current is induced in a metal layer by generating a high frequency magnetic field covering at least a part of the surface of the metal layer of the wafer, and the eddy current causes the surface of the metal layer of the wafer to be induced.
Up to a temperature that softens or fluidizes at least part of the surface
While heating, added high-frequency magnetic field and the metal layer is pressurized by interaction with eddy currents, electromagnetic induction type embedding method and performing embedding. 2. A disposed parallel to the vicinity of the surface of the metal layer of the wafer, the high-frequency magnetic field with at least one high-frequency coil for generating a high-frequency magnetic field so as to cover at least a portion of the metal layer surface of the U E c Generating means, and a high frequency power source for energizing the high frequency magnetic field generating means for generating a high frequency magnetic field
The metal layer of the wafer due to the eddy currents induced in the metal layer.
At a temperature that softens or fluidizes at least part of the surface
It is heated up to the same time, and the magnetic layer is pressed and buried by using magnetic pressure.
Electromagnetic induction type embedding processing unit and performs included because. 3. arranged in parallel in the vicinity of the surface of the metal layer of the wafer, the high-frequency magnetic field with at least one high-frequency coil for generating a high-frequency magnetic field so as to cover at least a portion of the metal layer surface of the U E c Generating means, a high frequency power source for energizing the high frequency magnetic field generating means for generating the high frequency magnetic field, and a control device for setting the frequency and current value of the high frequency current supplied from the high frequency power source to the high frequency magnetic field generating means.
The metal layer of the wafer due to the eddy currents induced in the metal layer.
At a temperature that softens or fluidizes at least part of the surface
It is heated up to the same time, and the magnetic layer is pressed and buried by using magnetic pressure.
Electromagnetic induction type embedding processing unit and performs included because. 4. A disposed parallel to the vicinity of the surface of the metal layer of the wafer, the high frequency magnetic field generating means having a plurality of magnets for generating a high-frequency magnetic field so as to cover at least a portion of the metal layer surface of the U E c If, Bei a high-frequency vibration generating devices for vibrating the high-frequency magnetic field generating means for generating a high frequency magnetic field
The surface of the metal layer of the wafer due to eddy currents induced in the metal layer.
To a temperature that softens or fluidizes at least part of
While heating, press the metal layer using magnetic pressure to embed
An electromagnetic induction type embedded processing device characterized by performing only 5. A are arranged in parallel in the vicinity of the surface of the metal layer of the wafer, and a high frequency magnetic field generating hand stage with a plurality of magnets for generating a high-frequency magnetic field so as to cover at least a portion of the metal layer the surface of the wafer, Bei a high frequency vibration generating devices for vibrating the high-frequency magnetic field generating means for generating a high frequency magnetic field, and a control device for setting the frequency and magnitude of vibrations to be supplied to the high frequency magnetic field generating means from the high-frequency vibration generating device
The surface of the metal layer of the wafer due to the eddy currents induced in the metal layer.
To a temperature that softens or fluidizes at least part of
While heating, press the metal layer using magnetic pressure to embed
An electromagnetic induction type embedded processing device characterized by performing only