KR20110120892A - Concentric hollow cathode magnetron sputter source - Google Patents

Abstract

A new sputter source is introduced that allows for a high deposition rate at one or two orders of magnitude lower than conventionally obtained pressures. This creates a higher density film on the substrate with reduced ionic and electron damage.

Description

Concentric Hollow Cathode Magnetron Sputter Source {CONCENTRIC HOLLOW CATHODE MAGNETRON SPUTTER SOURCE}

The present invention relates generally to sputter sources, more particularly to magnetron sputter sources, and more particularly to the use of sputter sources for the deposition of materials.

Deposition of materials using magnetron sputter sources has been in use for more than 30 years. A cross section of a conventional circular magnetron sputter source is shown in FIG. The sputter source 100 is disposed in the vacuum chamber 101. Vacuum chamber 101 is attached to a vacuum pump (not shown) via port 109. The magnet 106 is disposed in two concentric rings, attached to the iron yoke 107, and generates a strong electric field 104 that penetrates the target 108, which is mostly parallel to the target surface 109. (110) A strong electric field 100 parallel to the target surface 109 and generally> 300 gauss traps gas ions near the target surface 109 if ions are available for sputtering, so that the electric field is The size is increased and the corresponding sputtering rate is increased. A power supply (not shown) DC or RF is electrically attached from the chamber 101 to the target 108. The gas, which is generally argon, is metered into the vacuum chamber 101 through the MFC 111 at a pressure of generally 3 × 10 E-3 to 1 × 10 E-2 Torr. The power supply is turned on, the voltage rises to 300 to 400 volts for the DC power supply, and typically rises to 1 to 10 KW for the RF supply, resulting in sputtering of the target surface 109. The target material 108 is deposited on the substrate 105, which is held in place by the chuck 103 and is typically temperature controlled. Such an arrangement increases the proportion of material deposited from the target 108 to the substrate surface 105 by 10 to 100 layers compared to sputtering without the magnet 106.

Based on the magnetic field penetrating into the surface of the target and the magnetic field parallel to the target surface, a variety of different magnet arrangements have been used for sputtering. An example is shown in FIG. 2 and is known as a hollow cathode 200. The hollow cathode 200 is disposed in a vacuum chamber 101 attached to a vacuum pump (not shown) and has the same gas injection port 110 as in FIG. 1. The hollow cathode 200 is composed of a cylinder type housing 202. Two magnet rings 206 are attached to the iron yoke 207 to generate a strong magnetic field 204 that penetrates into the target 208. A DC or RF power supply (not shown) is attached from the vacuum chamber 101 to the target 208 as in FIG. Argon is introduced into the vacuum chamber 101 through the port 110 and is generally metered by the MFC 111 at a pressure of 3 × 10 E-3 to 1 × 10 E-2 torr. The power supply is turned on at 300 to 400 volts for the DC supply, and generally 1 to 10 KW for the RF supply. Sputtering occurs where the magnetic field 210 is mostly parallel to the target surface 209. The deposition rate on the substrate surface is several times greater than the deposition rate without magnets. The hollow cathode 200 generates directional sputtering and is used for sputtering into a substrate having an aspect ratio, ie, a shape of> 5: 1.

Thus, what is needed is a system and method that allows for high deposition rates at low pressures. The present invention addresses that need.

An object of the present invention is to provide a concentric hollow cathode magnetron sputter source.

A new sputter source is disclosed that allows for a high deposition rate at one or two orders of magnitude lower than previously attainable pressures. This creates a higher density film on the substrate with reduced ionic and electron damage.

1 shows an example of a cross section of a conventional circular magnetron sputter source.
2 shows an example of the prior art known as a hollow cathode.
3 shows a cross section of the invention, ie a sputter source composed of a circular housing.
4 is a plan view of the present invention, showing an inner ring of a magnet and an outer ring of a magnet arranged in a hexagon.

The present invention relates generally to sputter sources and more particularly to magnetron sputter sources, and more particularly to the use of sputter sources for the deposition of materials. The following detailed description is given to enable one skilled in the art to complete and use the present invention, and is provided within the context and requirements of a patent application. Various modifications and general principles and features of the preferred embodiments described herein will be readily appreciated by those skilled in the art. Therefore, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope without contradiction to the principles and features described herein.

The present invention relates to a "Concentric Hollow Cathode Sputter Source", wherein a cross section of a sputter source 300 consisting of a circular housing 302 is shown in FIG. 3. An outer hexagonal ring of two rows of magnets 306, 319 is attached to the iron yoke 302, and an inner hexagonal ring of two rows of magnets 306, 319 is also attached to the iron yoke 302. Iron yoke 302 is a return path for magnetic flux from all magnets.

4 is a plan view of the present invention and shows an inner ring 313 of a magnet and an outer ring 306 of a magnet arranged in a hexagon. Other configurations are possible, such as three sides, four sides, and the like, but six sides are preferred configurations. All magnets are attached to the iron yoke 307.

Referring to FIG. 3, the magnetic field has three components. The first component is the magnetic field 314 from the upper row 319 of the outer magnet to the lower row 306 of the outer magnet and penetrates into the outer row 312 of the target and is mostly parallel to the outer target surface 309. Traps ions close to the surface 309 and generates a high sputtering ratio from the external target surface 312. The second magnetic field 316 is generated from the inner row 318 of the upper magnet to the inner row 313 of the lower magnet and penetrates into the inner target 308 and is mostly parallel to the inner target surface 322 and is an inner target. Ions are trapped at face 322 and generate a high sputtering rate from inner target face 322. The third magnetic field 304 is generated from the outer ring 319 of the upper magnet to the inner ring 318 of the upper magnet. A similar magnetic field 321 is created below the cavity 315 between the outer ring of the lower magnet 306 and the inner ring of the lower magnet 313. Magnetic fields 304 and 321 trap ions and electrons in cavity 315, increasing ion density in cavity 315, and preferably between 2x10E-5 and 1x10E-2 Torr, preferably Sputtering is allowed at a pressure of 5 × 10 E-5 to 5 × 10 E-4 torr. Other sputter sources, such as planar source 100 and hollow cathode 200, require a pressure of 3x10E-3 to 1x10E-2 torr. The low pressure of this concentric hollow source 300 results in a higher density sputtered film with less trapped argon or any other gas (the gas used in the sputtering process) in the deposited film. In addition, the lower pressure increases the mean free path in vacuum, reduces the collision between gas molecules and the sputtered material, increases the average energy of the sputtered material reaching the substrate surface, and also deposits. To increase the density of the material. A second advantage of trapping ions and electrons in the cavity 315 is that the number of ions and electrons reaching the substrate surface is significantly reduced compared to the planar source 100 or the hollow cathode 200. Reduced ions and electrons reaching the substrate surface 105 significantly reduce ion and electron damage in semiconductor devices fabricated on the substrate surface 105.

Although the invention is described in accordance with the illustrated embodiments, those skilled in the art will readily recognize that variations of the embodiments are possible within the spirit and scope of the invention. For example, although the junction may be preferably made of a conductive material such as aluminum, it may also be made using a non-conductive material with conductive properties added to the surface within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended specification.

Claims (10)

A concentric sputter source in a vacuum chamber, wherein the concentric sputter source comprises two rows of magnets in the outer ring and two rows of magnets in the inner ring. The method of claim 1,
Two rows of magnets of the outer ring and two rows of magnets of the inner ring, the magnetic pole on the upper ring attracts the magnet of the inner upper ring, attracts the magnet of the outer ring, the magnet of the inner lower ring A concentric sputter source, characterized in that it is arranged to attract a magnet of the outer lower ring. The method of claim 1,
The magnet of the outer ring is attached to the first iron yoke which is the return path of the magnetic field,
The magnet of the inner ring is attached to a second iron yoke, the return path of the magnetic field. The method of claim 1,
Wherein said inner magnet ring and outer magnet ring consist of at least three sides. The method of claim 1,
The inner magnet ring and the outer magnet ring are preferably composed of six sides. The method of claim 1,
A concentric sputter source, characterized in that the magnetic field at the target surface is between 200 and 1000 gauss. The method of claim 1,
The magnetic field at the target surface is preferably 300 to 400 gauss. The method of claim 1,
And the magnetic field from the outer magnet ring to the inner magnet ring is between 300 and 1000 gauss. The method of claim 1,
The magnetic field from the outer magnet ring to the inner magnet ring is preferably 300 to 400 gauss. The method of claim 1,
The vacuum chamber is operated at a pressure as low as 2 x 10E-5 Torr.

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