Browse Prior Art Database

Modified Magnetron

IP.com Disclosure Number: IPCOM000044949D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 3 page(s) / 31K

Publishing Venue

IBM

Related People

Guarnieri, CR: AUTHOR [+3]

Abstract

This article relates generally to magnetron sputtering apparatus and more particularly to modification of conventional magnetron sputtering apparatus which converts it to a low energy, ion beam source.

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Modified Magnetron

This article relates generally to magnetron sputtering apparatus and more particularly to modification of conventional magnetron sputtering apparatus which converts it to a low energy, ion beam source.

Magnetrons are used to sputter deposit materials on substrates.

The character of the interface between the deposited layer and the substrate is strongly dependent on the cleanliness of the surface before deposition. A technique that has been found very effective is a cleaning operation with a low energy ion beam, in vacuum, immediately prior to deposition. With only a short interval between the cleaning and deposition, in a vacuum environment, the opportunity for contamination prior to deposition is minimized. However, it is difficult to obtain in atmosphere the degree of cleanliness that is possible with the sequence outlined.

One approach used to clean surfaces prior to deposition is a glow discharge. A low energy plasma is generated throughout the vacuum chamber in this approach, with the ions striking all internal surfaces of the facility. Because of the nondirected nature of the ions, contaminants are also sputtered onto the substrates due to ion bombardment elsewhere in the facility. This contamination is a serious shortcoming of the glow discharge approach and would be greatly reduced if the ions were directed only towards the exposed substrate surfaces. This is essentially what happens in the next alternate solution to be considered.

For the quality of cleaning (or etching) involved, the best alternate approach would be the addition of an ion source, together with means for ion beam acceleration, to the vacuum system. This alternate approach has some major shortcomings. First, it requires that a complex and expensive ion source be added to a space that is usually quite limited. Second, at best, the ion beam from a separate ion source will not give uniform coverage of the substrates. This is because the central position desirable for uniform coverage is already occupied by the magnetron.

The figure shows a schematic of a combined ion beam-magnetron apparatus which does not suffer from any of the shortcomings of other approaches.

In the figure, the elements of a conventional magnetron are shown. A conventional magnetron consists of a target 1, a substrate holder 2, substrates 3, a magnetic field 4 (means for producing the magnetic field not shown, but located above target 1), and a ground shield 5. All of these components are located within a vacuum environment (not shown).

The modification required to produce a low energy ion beam is the addition of an electrode 6 and cathodes 7 and 8. This modification converts the region near target 1 and within the strong magnetic field 4 into an electron bombardment ion source, and the region closer to target 1 into a Hall-curr...