Plasma immersion ion implantion apparatus and method

Abstract

A plasma immersion ion implant apparatus and method, and a plasma chamber, each configured to provide a uniform ion flux and to dissipate the effects of secondary electrons are disclosed. The invention includes a plasma chamber including a dielectric tophat configuration and a conductive top section that may be liquid cooled. In addition, the invention provides a radio frequency (RF) antenna configuration including an active antenna that is coupled to an RF source and a parasitic antenna that is not directly coupled to any RF source, but may be grounded. The RF antenna allows for tuning of the RF coupling.

Description

BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention relates generally to plasma immersion, and more particularly to plasma immersion ion implanting via an apparatus having a conductive top section on a dielectric tophat plasma chamber configuration, an RF antenna having an active and parasitic antenna, and controlled gas flow. [0003] 2. Related Art [0004] Plasma apparatuses in semiconductor processing are widely used and accepted for etching and chemical vapor deposition (CVD). In addition, plasma apparatus are gaining in popularity for ion implantation. Relative to ion implantation, however, low throughputs at low energies with traditional ion implanting tools has made plasma immersion ion implant technology very attractive. Traditional plasma doping (PLAD) relies upon a negative voltage applied to a substrate to generate the plasma with the appropriate gas species, extract the positive ions and implant them into the substrate. At high implant voltage...

AI Technical Summary

Benefits of technology

[0011] The invention includes a plasma immersion ion implant apparatus and method, and a plasma chamber, each configured to provide a uniform ion flux and to dissipate the effects of secondary electrons. The invention includes a plasma chamber including a dielectric tophat configuration and a conductive top section that may be liquid cooled. In addition, the invention provides a radio frequency (RF) antenna configuration including an active antenna that is coupled to an RF source and a parasitic antenna that is not coupled to any RF source and can be grounded at one point. The RF antenna allows for tuning of the RF coupling. A plasma igniter that provides a strike gas may also be provided to assist plasma ignition.

Problems solved by technology

However, the bulk of PLAD's market is for low implant voltage, which is a very inefficient way of producing ions, thus reducing wafer throughput.

Whether the goal is to etch circuit features, deposit layers of insulators or metals, or in this instance, implant ions into the wafer surface, one challenge is creating uniform plasma.

This issue is especially important relative to ion implantation because a uniform ion flux impinging on the water is necessary.

Another challenge relative to ion implantation is addressing secondary election emission from the wafer.

As a consequence, the charged chamber top adversely affects implant uniformity energy and process repeatability.

Unfortunately, this approach results in excessive charging of the ceramic, which results in process variability.

However, this approach suffers from similar issues with heat.

In addition, charge removal becomes a major issue with this approach.

Each of these disclosures, however, suffer from similar issues associated with secondary electrons.

Another challenge for plasma processing is plasma ignition.

In particular, certain process gases may be difficult to ionize due to: their composition, pressure or the type of RF antenna or operating parameters (e.g., power and frequency).

However, none of these approaches adequately address difficult to ionize process gases that are practically impossible to ignite into a plasma (e.g., diborane in helium (15% B2H6 in 85% He) is extremely difficult to ionize).

Difficulty in plasma ignition at a given set of desired process conditions limits the ability to operate at the optimum condition.

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