Method and appts. for ionized sputtering of materials

Abstract

An ionized physical vapor deposition apparatus (10, 10a, 10b) is provided with an RF element, preferably a helical coil (30), that surrounds space (11) within a vacuum chamber (12) between a target (16) and a substrate holder (14). RF energy, preferably at about 2 MHz or elsewhere in the 0.1 to 60 MHz range, is coupled into the space to form a secondary plasma (29) in a volume (26) of the space between the substrate holder and the main plasma that is adjacent the target. The secondary plasma ionizes sputtered material which is then attracted toward a substrate (15) on the support by a bias on the substrate and / or by an axial magnetic field to impart directionality to the moving ionized sputtered particles to render them perpendicular to the substrate at incidence, so as to coat the bottoms of narrow high aspect ratio features on the substrate. A window (60) of dielectric material such as quartz, either in the wall of the chamber or inside the chamber, or insulation on the coil, protects the coil from adverse interaction with plasma. Shields (100, 200, 300) between the space and the dielectric material prevent sputtered particles coating the dielectric material. The shields are partitioned or slotted to prevent induced currents in the shields. The shields may be biased to control contamination and may be commonly or individually biased to optimize the uniformity of coating on the substrate and the directionality of the flux of ionized material at the substrate. The shield may be formed of a plurality of angled segments (302) that are spaced to facilitate communication of a secondary RF plasma from adjacent the window to the volume of the chamber where the sputtered material is ionized, with the sections angled and spaced to shadow at least most of the target from the window. Alternatively, electrically conductive shield (100) may be provided in close proximity to the window or insulation.

Description

[0001] This invention relates to sputter coating, and more particularly to methods and apparatus for ionized physical vapor deposition (IPVD) of coating materials onto substrates. Background of the invention [0002] The presence of high aspect ratio features such as vias, trenches, and contact holes in semiconductor production poses various coating problems. In the production of very large very large scale integration (VLSI and ULSI) semiconductor devices, contacts are often lined on the bottom of such features and the features are often filled with conductive metal. In many semiconductor device manufacturing situations where thin films are to be deposited, it is either required or at least preferred to apply a coating using a physical vapor deposition (PVD) process. Physically depositing thin films on the bottom of narrow, high aspect ratio features (wall holes) requires a high degree of orientation in the motion of the deposited material towards the substrate. Higher aspec...

AI Technical Summary

Problems solved by technology

Higher pressures have a tendency to degrade the quality of the deposited film properties and increase membrane fouling

In addition, higher operating pressures reduce the uniformity of the processed planar field, forcing larger vacuum chamber designs, which further reduces ionization efficiency

Other problems posed by the prior art IPVD process are that the RF electrodes or components are undesirably sputtered due to plasma, undesired deposition on which accumulated sputtered material is spalled by the RF components, RF components Shorting and other plasma and material interactions with electrodes or components used to couple RF energy into the plasma to ionize the sputtered material

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