Detecting analytic system

Abstract

A radio frequency (RF) detection analysis system has a broadband design. The analysis system includes a sampling unit for generating a digital power signal from a plurality of analog signals. These analog signals represent the power supplied to a plasma chamber by an RF power supply system. The analysis system also includes a digital processing unit for generating a digital spectrum signal from the digital power signal. The sampling unit simultaneously samples the first plurality of frequencies from the analog signal such that the digital spectrum signal specifies signal levels of the first plurality of frequencies. The sampling unit may also simultaneously sample a second plurality of frequencies from the analog signal such that the digital spectrum signal also specifies signal levels of the second plurality of frequencies. The broadband design of the sampling cell enables closed-loop control of the power supplied to the chamber to tolerances not achievable by conventional methods.

Description

technical field [0001] The present invention generally relates to plasma etching of semiconductors. In particular, the present invention relates to a radio frequency (RF) detection analysis system having a broadband design. Background technique [0002] In the semiconductor industry, plasma etching has become an integral part of fabricating semiconductor circuits. In fact, etchers are frequently used in semiconductor processing when a straighter vertical edge is required. For example, when etching the polysilicon gate of a MOS transistor, undercutting the polysilicon can have a detrimental effect on the operation of the transistor. Undercutting is often encountered when using liquid etching methods. As a result, other etching techniques such as plasma etching have been developed. Plasma etching using ions accelerated by an electric field tends to etch only horizontal exposed surfaces avoiding undercutting. [0003] In order to efficiently perform plasma etch processes (...

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Problems solved by technology

Furthermore, the processing costs associated with this method are high due to the separate processing of each frequency

Furthermore, this conventional approach typically uses analog circuits, which inherently have filters with non-linear phase responses, lacking the resilience to tolerate aging and drift

Especially with regard to channel-to-channel matching, it has been encountered that conventional designs do not provide a system resilient to aging, drift or alignment

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