ANODE LAYER ION SOURCE AND ION BEAM SPUTTER DEPOSITION MODULE

An anode layer ion source includes a magnetic field generating member, an upper cathode electrode, a lower cathode electrode, a case member, and an anode electrode. The magnetic field generating member generates a magnetic field. The upper cathode electrode and the lower cathode respectively have two end members and form an opening there between. The two end members are two ends of the opening and guide the magnetic field to the opening, and the magnetic field in the openings is substantially parallel to the connection of two ends of the opening. The case member, the upper cathode electrode, and the lower cathode electrode form an accommodating cavity. The anode electrode is disposed in the accommodating cavity and generates an electric field to the opening. The electric field in the opening is substantially perpendicular to the magnetic field in the opening.

RELATED APPLICATIONS

This application claims priority to Taiwanese Application Serial Number 104117375, filed May 29, 2015, which are herein incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to an anode layer ion source and an ion beam sputter deposition module.

2. Description of Related Art

Sputtering is a physical vapor deposition process whereby particles are ejected from a solid target material due to bombardment of the target by energetic ions. Sputtering generally is performed in a nearly vacuumed system filled with inert gas, such as argon, and the argon gas is ionized due to the high voltage electric field, such that the argon ions are generated and hit the target. Then, atoms or molecules that are ejected from the target material are deposited and form a thin film on the semiconductor wafer, glass, or ceramic. Because sputtering can be performed to form a thin film made of a material with a high melting point, and the composition of the target material can be maintained without change when an alloy thin film or a compound thin film is formed, sputtering is widely applied in the manufacturing of the semiconductor devices and the integrated circuits.

To further improve various characteristics of the sputtering process and the associated apparatuses, persons in the industry all endeavor to search for practical solutions. The application of the sputtering process and the associated apparatuses is one of many important research topics, and is also a target that needs to be improved in many related fields.

SUMMARY

This disclosure provides a module that integrates an anode layer ion source with a sputtering target to minimize vacuum chamber volume and to enhance the sputtering efficiency.

In one aspect of the disclosure, an anode layer ion source is provided. The anode layer ion source includes a magnetic field generating member, a cathode electrode, a case member, and an anode electrode. The magnetic field generating member is configured to generate a magnetic field. The cathode electrode includes an upper cathode electrode and a lower cathode electrode. The upper cathode electrode has a first end member. The lower cathode electrode has a second end member. An opening is formed between the first end member and the second end member, and the first end member and the second end member are two ends of the opening. The cathode electrode guides the magnetic field generated by the magnetic field generating member to the opening, and the magnetic field in the opening is substantially parallel to the connection of the two ends of the opening. The case member and the cathode electrode form an accommodating cavity. The anode electrode is disposed in the accommodating cavity and configured to generate an electric field to the opening, and the electric field in the opening is substantially perpendicular to the magnetic field in the opening.

In one or more embodiments, potentials of the anode electrode and the cathode electrode are greater than zero.

In one or more embodiments, a potential of the upper cathode electrode is different from a potential of the lower cathode electrode that they act as electrostatic-magnetic wehnelt electrodes.

In one or more embodiments, the magnetic field generating member is a permanent magnet.

In one or more embodiments, the magnetic field generating member is an electromagnet.

In one or more embodiments, the cathode electrode is made of a material that is both magnetoconductive and electrical conductive.

In one or more embodiments, shapes of the first end member and the second end member are annular, oval or racetrack shaped.

In one or more embodiments, a normal of the opening is not perpendicular to a symmetry axis of the first end member.

In another aspect of the disclosure, an ion beam sputter deposition module is provided. The ion beam sputter deposition module includes a target and the anode layer ion source. The anode layer ion source is configured to provide an ion beam to be emitted on the target in an inclined angle.

In one or more embodiments, an incident angle in which the ion beam is emitted on the target is in a range from about 30° to about 65°.

Because the potential of the cathode electrode is greater than zero, the cathode electrode generates outwardly diverging electric fields. This cathode electrode act as wehnelt electrode. Therefore, when ions (for example, positively charged argon ions) move away from the anode electrode, at first some of the ions may move toward the cathode electrode. However, ions will be repelled by the cathode electrode due to the electric fields generated by the cathode electrode when the distance between the ions and the cathode electrode become smaller, such that the ions will not hit the cathode electrode. Therefore, because the ions do not hit the cathode electrode, the anode layer ion source will not overheated, and the cathode electrode will not be damaged by the hits of the ions. Meanwhile, because no ions are wasted due to the bombardment of the ions on the cathode electrode, the sputtering efficiency is effectively enhanced.

The upper cathode and the lower cathode electrode do not have to be at the same potential. The potential on each cathode electrode can be adjusted independently by individual power supplies to optimize sputter rate and minimize cathode erosion. Thus the upper cathode and the lower cathode act as asymmetric electrostatic-magnetic wehnelt electrodes.

DETAILED DESCRIPTION

In other instances, well-known structures and devices are schematically depicted in order to simplify the drawings.

FIG. 1is a schematic perspective view of an ion beam sputter deposition module100utilizing an anode layer ion source300according to one embodiment of this invention.FIG. 2is a cross-sectional view viewed along line2-2ofFIG. 1. As shown inFIG. 1andFIG. 2, an ion beam sputter deposition module100is provided. The ion beam sputter deposition module100includes a target200and an anode layer ion source300. The anode layer ion source300provides an ion beam400to be emitted on the target200in an inclined angle. A substrate for materials to be deposited (not shown in Figs.) is disposed directly above the target200.

FIG. 3is a partially enlarged view ofFIG. 2. As shown inFIG. 3, the anode layer ion source300includes a magnetic field generating member310, a cathode electrode320, a case member330, and an anode electrode340. The magnetic field generating member310generates a magnetic field500. The cathode electrode320includes an upper cathode electrode321and a lower cathode electrode325. The upper cathode electrode321has a first end member322. The lower cathode electrode325has a second end member326. An opening329is formed between the first end member321and the second end member325, and the first end member322and the second end member326are two ends of the opening329. The cathode electrode320guides the magnetic field500generated by the magnetic field generating member310to the opening329, and the magnetic field500in the opening329is substantially parallel to the connection of the two ends of the opening329. The case member330and the cathode electrode320form an accommodating cavity332. The case member330can be grounded or floated. The anode electrode340is disposed in the accommodating cavity332and generates an electric field600to the opening329. The electric field600in the opening329is substantially perpendicular to the magnetic field500in the opening329. It is noted that directions of the magnetic field500and the electric field600are illustrative, and the directions of the magnetic field500and the electric field600in actual situations may be slightly different from the directions of the magnetic field500and the electric field600shown inFIG. 3.

Specifically, the potentials of the anode electrode340and the cathode electrode320are greater than zero. Embodiments of this disclosure are not limited thereto. The person having ordinary skill in the art can make proper modifications to the anode electrode340and cathode electrode320depending on the actual application.

As shown inFIG. 2andFIG. 3, when the anode layer ion source300generates the ion beam400, first, the vacuum chamber where the ion beam sputter deposition module100is positioned is vacuumed, and working gas such as argon is filled into the module through opening331. Then, the electric field600is generated to the opening329. Because the magnetic field500generated by the magnetic generating member310is guided to the opening329, and the magnetic field500in the opening329is substantially parallel to the connection of the two ends of the opening329, electrons will moves in a helical trajectory toward the anode electrode340due to the influence of the magnetic field500and the electric field600. When the electrons are moving, some of the electrons will hit argon atoms, such that positive argon ions are generated. Positive argon ions will be pushed away from the anode electrode340due to the influence of the electric field600, such that the ion beam400is formed.

Because the potential of the cathode electrode320is greater than zero, the cathode electrode320generates outwardly diverging electric fields as well. Therefore, when ions (positively charged) move away from the anode electrode340, at first some of the ions may move toward the cathode electrode320. However, ions will be repelled by the cathode electrode320due to the electric fields generated by the cathode electrode320such that ions will not hit the cathode electrode320. Therefore, because ions do not hit the cathode electrode320, the cathode electrode320will not be damaged. Meanwhile, because no ions are wasted, the sputtering efficiency is effectively enhanced.

Further, only direct current power supply is needed to be the power supply of the ion beam sputter deposition module100to complete all kinds of the required sputterings (for example, the metal film sputtering or the insulation film sputtering). Compared to the conventional magnetron sputtering module, which usually uses alternating current power supply as its power source, the manufacturing cost of direct current power supply of the ion beam sputter deposition module100is much lower than the manufacturing cost of the alternating current power supply. In addition, because the operating power of the direct current power supply of the ion beam sputter deposition module100is much lower than the operating power of the alternating current power supply of the conventional magnetron sputtering module (for example, the ion beam sputter deposition module100and the conventional magnetron sputtering module provide approximately the same sputtering quality when the power of the direct current power supply of the ion beam sputter deposition module100is 10 watts and the power of the alternating current power supply (13.5 MHz) of the conventional magnetron sputtering module is 70 watts to 80 watts), the electricity needed for the sputtering is reduced, such that the sputtering cost can be further reduced.

FIG. 4is a schematic perspective view of the anode layer ion source300according to another embodiment of this invention. As shown inFIG. 4, the anode layer ion source300further includes a magnetic field generating member312. The magnetic field generating member312cooperates with the magnetic generating member310to generate the magnetic field500. Embodiments of this disclosure are not limited thereto. In other embodiments, the anode layer ion source300may only include the magnetic field generating member312, and the anode layer ion source300does not include the magnetic field generating member310.

The magnetic field generating members310and312may be permanent magnets or electromagnets. In addition, when the magnetic field generating members310and312are electromagnets, the potentials of the magnetic field generating members310and312and the cathode electrode320need not to be the same. Specifically, because the function of the magnetic field generating members310and312is to generate the magnetic filed500, and the function of the cathode electrode320is to guide magnetic field500to the opening329and generate outwardly diverging electric field to repel the ions, such that the ions will not hit the cathode electrode320, the function of the magnetic field generating members310and312is different from the function of the cathode electrode320. Therefore, the potentials of the magnetic field generating members310and312and the cathode electrode320need not to be the same.

Specifically, the cathode electrode320are made of a material that is both magnetoconductive and electrical conductive that act as electrostatic-magnetic wehnelt electrode. Embodiments of this disclosure are not limited thereto. The person having ordinary skill in the art can make proper modifications to the cathode electrode320depending on the actual application.

Therefore, the cathode electrode320guides the magnetic field500to the opening329by the magnetoconductive material properties. And, the reason why the cathode electrode320is electrically connected to the external power supply is to generate outwardly diverging electric field to repel positive ions.

Specifically, the shapes of the first end member322and the second end member326are annular, oval or racetrack shaped, such that the shape of the opening329becomes a side surface of a virtual column (seeFIG. 1) and the opening329faces the cylinder axis of the virtual column. Meanwhile, the upper cathode electrode321, the lower cathode electrode325, and the anode layer ion source300may be annular, oval or racetrack shaped structures as well.

Therefore, because the opening329is substantially annular, oval or racetrack shaped the ion beam400moves to the target200from different directions, such that the distribution of the ion beam400is symmetric. Therefore, the thicknesses of different parts of the thin film deposited on the substrate are approximately the same.

Specifically, the normal329nof the opening329(the normal329nis basically perpendicular to the connection of the two ends of the opening329) is not perpendicular to a symmetry axis S of the first end member322, or the normal329nof the opening329is not perpendicular to the cylinder axis of the aforementioned virtual column. In addition, the symmetry axis S may be the symmetry axis of the second end member322, the upper cathode electrode321, the lower cathode electrode325, the anode layer ion source300, or the ion beam sputter deposition module100.

Because the normal329nis approximately parallel to the moving direction of the ion beam400, and the symmetry axis S is perpendicular to the top surface of the target200, the ion beam400is emitted to the target200in at an inclined angle. Then, because the ion beam400is emitted to the target200in an inclined angle, the target200can be sputtered and deposited on substrates positioned upstream of the target200. Therefore, the target200and the anode layer ion source300are effectively integrated, the total volume of the accommodating space328and the accommodating cavity332is smaller than the volume needed for accommodating similar components in the conventional ion beam sputtering module. Then, a smaller vacuum pump is needed for the ion beam sputter deposition module100.

The angle θ between the normal329nof the opening329and the symmetry axis S is in a range from about 30 to about 65 or in a range from about 55° to about 65°. In other words, the incident angle in which the ion beam400is emitted on the target200may be in a range from about 30° to about 65° or in a range from about 55′ to about 65°. Therefore, in the aforementioned condition, after the target200is hit by the ion beam400, the target200can emit the sputtering material in the maximum efficiency, such that the sputtering efficiency is effectively enhanced. The angle θ between the normal329nof the opening329and the symmetry axis S may further be about 60°.

In the aforementioned embodiments, the potentials of the upper cathode electrode321and the lower cathode electrode325are substantially the same. Embodiments of this disclosure are not limited thereto. In other embodiments, the potential of the upper cathode electrode321is different from the potential of the lower cathode electrode325. Therefore, by adjusting the potentials of the upper cathode electrode321and the lower cathode electrode325, the incident angle in which the ion beam400is emitted on the target200can be adjusted to optimize deposition efficiency.

As shown inFIG. 4, the case member330further includes inlet331. Therefore, when the accommodating cavity332and its surrounding is vacuumed, inert gas such as argon can enter the accommodating cavity332through the inlet331.

As shown inFIG. 2, the ion beam sputter deposition module100further includes a heat-dissipating base700and a shielding structure800. The target200and the anode layer ion source300are both disposed on the heat-dissipating base700. The shielding structure800is disposed above and covers the cathode electrode320, and the shielding structure800is not electrically connected to the cathode electrode320. The shield structure800shields the electric field generated by the cathode electrode320, and the shield structure800can be grounded.

FIG. 5is a film thickness to horizontal position figure of a thin film deposited on a substrate by the ion beam sputter deposition module100according to one embodiment of this invention. In the embodiment, the ion beam sputter deposition module100is positioned in a vacuum chamber and pumped down to 2×10−5torr. Argon gas enters the accommodating cavity332through the inlet331, and the flow rate of the argon gas is 2.6 sccm (standard cubic centimeters per minute). The potential of the anode electrode340is 1000 volts. The discharge current of the anode electrode340is 10 mA. The target200is made of copper (purity=99.99%). The substrate to be sputtered is made of glass, and the distance between the substrate and the target200is 65 mm. The sputtering time is 3 hours. As shown inFIG. 5, the thickness of the thin film deposited on the substrate is in a range from about 400 nm to 600 nm, and the deviation is approximately less than 20%.

FIG. 6is a figure showing currents collected by the upper cathode electrode due to argon ion bombardment at various anode electrode voltages when the anode layer ion source300is sputtering according to different embodiments of this invention. It is noted that the parameters described above will not repeated again. The connections910and920respectively represent the relation between the current of the upper cathode electrode321and the potential of the anode electrode340in two embodiments. In the two embodiments, the flow rate of the argon gas is 3 sccm. In the embodiment corresponding to the connection910, the upper cathode electrode321is grounded. As shown inFIG. 6, when the potential of the anode electrode340is increased from 700 volts to 1500 volts, the current generated by argon ions hitting the upper cathode electrode321is increased from 0 mA to 5 mA and then decreased to 4 mA. In the embodiment corresponding to the connection920, a bias voltage is applied to the upper cathode electrode321, such that the potential of the upper cathode electrode321is not zero. As shown inFIG. 6, when the potential of the anode electrode340is increased from 700 volts to 1500 volts, the current generated by the ions hitting the upper cathode electrode321keeps under 0.2 mA. Therefore, when the potential of the upper cathode electrode321is greater than zero, the probability that the ions hit the upper cathode electrode321can be effectively reduced.

Because the potential of the cathode electrode320is greater than zero, the cathode electrode320generates outwardly diverging electric fields. Therefore, when ions move away from the anode electrode340, at first some of the ions may move toward the cathode electrode320. However, ions will be repelled by the cathode electrode320due to the electric fields generated by the cathode electrode320when the distance between the ions and the cathode electrode320become smaller, such that ions will not hit the cathode electrode320. Therefore, because ions do not hit the cathode electrode320, the anode layer ion source300will not overheated, and the cathode electrode320will not be damaged by ion bombardment. Meanwhile, because no ions are wasted, the sputtering efficiency is effectively enhanced.

The upper cathode electrode321and the lower cathode electrode325do not have to be at the same potential. These two cathode electrodes together act as an electrostatic-magnetic wehnelt electrode. The potential on321and325can be adjusted by separate power supplies, while their geometrical shape can also be adjusted that the number of ions impinging on the target can be maximized while ions hitting the cathode can be mimimized.