Control of Impedance of RF Delivery Path

Abstract

A plasma system includes an RF generator and a matchbox including an impedance matching circuit, which is coupled to the RF generator via an RF cable. The plasma system includes a chuck and a plasma reactor coupled to the matchbox via an RF line. The RF line forms a portion of an RF supply path, which extends between the RF generator through the matchbox, and to the chuck. The plasma system further includes a phase adjusting circuit coupled to the RF supply path between the impedance matching circuit and the chuck. The phase adjusting circuit has an end coupled to the RF supply path and another end that is grounded. The plasma system includes a controller coupled to the phase adjusting circuit. The controller is used for changing a parameter of the phase adjusting circuit to control an impedance of the RF supply path based on a tune recipe.

Description

technical field

[0001] Embodiments of the invention relate to controlling the impedance of a radio frequency (RF) delivery path. Background technique

[0002] A plasma-based system includes a supply for generating a signal. The plasma-based system further includes a chamber that receives the signal to generate the plasma. Plasmas are used for a variety of operations, including cleaning wafers, depositing oxides and films on wafers, and etching away a portion of a wafer or a portion of oxides and films.

[0003] It is difficult to control some properties of the plasma, such as standing waves in the plasma, etc., so that the uniformity of plasma etching or deposition can be controlled. Difficulties in controlling plasma performance lead to non-uniformity in the material etched or deposited on the wafer. For example, the wafer is etched more at a first location from its center than at a second location from the center. The second distance is farther from the center than the...

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