Plasma process apparatus

Abstract

A disclosed a plasma process apparatus includes a process chamber that houses a substrate subjected to a predetermined plasma process and may be evacuated to a reduced pressure; a microwave generator that generates microwaves for generating plasma; a waveguide pipe that transmits the microwaves from the microwave generator to the process chamber; a waveguide pipe / coaxial pipe converter connected to one end of the waveguide pipe; and a coaxial pipe that forms a line through which the microwaves are transmitted from the waveguide pipe-coaxial pipe converter to the process chamber. An inner conductive body of the coaxial pipe has a hollow portion; and a first process gas supplying portion that supplies a process gas into the process chamber through the hollow portion of the inner conductive body of the coaxial pipe.

Description

TECHNICAL FIELD[0001]The present invention relates to a microwave plasma process apparatus that utilizes microwaves so as to carry out a predetermined plasma process, specifically to a microwave plasma process apparatus that supplies microwave power to plasma in a process chamber through electromagnetic wave coupling.BACKGROUND ART[0002]In plasma processes for fabricating semiconductor devices, liquid crystal displays (LCD), and the like, radio frequency (RF) waves and microwaves are used so as to discharge or ionize a process gas in a vacuum process chamber. An RF plasma apparatus mainly employs capacity coupling where a pair of electrodes is located, one electrode in parallel with the other leaving an appropriate gap between the electrodes in the process chamber. The RF waves are applied to one of the electrodes through a capacitor while the other electrode is grounded. However, it is difficult to produce high density plasma at relatively low pressures in the RF plasma apparatus. ...

AI Technical Summary

Benefits of technology

[0019]As another preferred embodiment of the present invention, the plasma process apparatuses with at least one of the above-stated additional features may be provided with a second process gas supplying portion that introduces a process gas into the chamber. The second process gas supplying portion may include a side wall eject hole from which the process gas is ejected toward a center portion of the process chamber. In this case, there may be provided a first flow rate control portion that controls the flow rate of the process gas introduced into the process chamber through the first process gas supplying portion; and a second flow rate control portion that controls the flow rate of the process gas introduced into the process chamber through the second process gas supplying portion. With these, flow rates or the flow ratio of the process gasses introduced into the process chamber from the corresponding process gas supplying portions are controlled, thereby improving plasma density and distribution uniformity.

[0025]In the plasma process apparatus according to the fourth aspect of the present invention, the process gas from a process gas supplier of the first process gas supplying portion flows through the gas conduit, which is grounded, and the dielectric window. Therefore, the process gas is not exposed to an electric field due to the microwaves, and thus abnormal discharging can be prevented.

[0027]As another preferred embodiment, a gas ejection portion of the gas conduit may protrude into the process chamber from the dielectric window, and specifically the gas ejection portion of the gas conduit is preferably at a distance 10 mm or more from the dielectric window in the plasma process apparatus according to the fourth aspect. With this configuration, the gas ejection portion can be located out of a plasma generation region, or in a plasma diffusion region, so as to prevent abnormal discharging around the gas ejection portion.

[0030]As another preferred embodiment of the present invention, the gas conduit is formed in an inner conductive body in the plasma process apparatus according to the fourth aspect with at least one of the above-stated additional features. In this case, the inner conductive body preferably includes a hollow portion that may be used to allow gas to flow therethrough, the hollow portion extending along a center axis of the inner conductive body. Moreover, the gas conduit is preferably in communication with the hollow portion and extends into the process chamber through a through hole made in the dielectric window. With these, the process gas can be introduced into the process chamber through an efficient and simplified gas introduction configuration.

[0032]As another preferred embodiment of the present invention, the plasma process apparatus according to the fourth aspect further includes a second process gas supplying portion that introduces the process gas into the chamber. The second process gas supplying portion may include a side wall eject hole from which the process gas is ejected toward a center portion of the process chamber. In this case, the plasma process apparatus according to the fourth aspect further includes a first flow rate control portion that controls a flow rate of the process gas introduced into the process chamber by the first process gas supplying portion; and a second flow rate control portion that controls a flow rate of the process gas introduced into the process chamber by the second process gas supplying portion. With these, flow rates or the flow ratio of the process gasses introduced into the process chamber from the corresponding process gas supplying portion are controlled, thereby improving plasma density and distribution uniformity.

[0035]According to embodiments of the present invention, a plasma process apparatus that can prevent abnormal discharging in a microwave transmission line or radiation path, or a process gas ejection portion, is provided, so that plasma excellent in plasma density uniformity and controllability can be realized, thereby improving performance or quality of the plasma process. In addition, a plasma process apparatus in which plasma conditions or a plasma process can easily be monitored may also be provided.

Problems solved by technology

However, it is difficult to produce high density plasma at relatively low pressures in the RF plasma apparatus.

In addition, it is disadvantageous in that device elements on a wafer are more frequently damaged during the plasma process because the RF plasma inherently has high electron temperatures.

In the first configuration, while it is advantageous in that the plasma can be uniformly produced above the susceptor, the plasma density tends to be lower, which leads to a low etching rate when the plasma process apparatus is an etcher, and an inefficient process as a whole.

In addition, such a configuration may cause a problem of contamination or the like.

On the other hand, in the second configuration, since the microwaves do not pass through the gas ejection holes made in the side wall of the chamber, abnormal discharging is unlikely to take place.

However, it is difficult to diffuse the process gas uniformly in a radial direction, resulting in nonuniformly distributed plasma.

Therefore, the process gas is exposed to the microwave electric field when flowing through the dielectric window, and thus may be ionized in a gas conduit in the dielectric window or near the gas ejection hole, which causes abnormal discharging.

Such abnormal discharging may affect the dielectric window, so that the dielectric window is deteriorated or damaged in a relatively short period of time, and may impair process performance.

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