Plasma processor

Abstract

An electromagnetic field generating coil included in plasma processing apparatus is realized with a balanced transmission line. Conductors constituting the balanced transmission line are disposed vertically above a wafer. A uniform electromagnetic field is generated in parallel with the wafer using the balanced transmission line. A gas inlet is formed above the balanced transmission line so that a gas will flow into the wafer after passing through the electromagnetic field generated around the balanced transmission line. The balanced transmission line may be formed spirally.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to plasma processing apparatus, or more particularly, to plasma processing apparatus for performing, for example, plasma chemical vapor deposition (CVD) or plasma etching in the course of manufacturing a semiconductor. [0003] 2. Description of the Related Art [0004] In the past, plasma has been utilized in a process of performing coating or layering, surface refining, etching, or the like, and has contributed to great successes. The plasma may be referred to as a state attained when an inert gas or a reactive gas introduced into an electromagnetic field, which is generated by a direct current, a high-frequency wave, or a microwave, while being depressurized is ionized through the collision of accelerated electrons and gaseous molecules. Thus, the plasma is composed of particles such as chemically active ions and free radicals (excitation atoms or molecules). [0005] For example, a plasma...

AI Technical Summary

Benefits of technology

[0015] Accordingly, an object of the present invention is to provide plasma processing apparatus capable of efficiently introducing a high-frequency power so as to generate a uniform electromagnetic field.

[0017] In the balanced transmission line, if a load impedance at a terminal is equal to the characteristic impedance of the balanced transmission line, an impedance match is attained, and an electromagnetic wave is entirely formed with a traveling wave alone. Consequently, a high-frequency power is efficiently transmitted, and a generated electromagnetic field advances in the direction of the transmission and is therefore uniform in the direction thereof.

[0024] The balanced transmission line may be disposed outside a vacuum chamber. Moreover, one of the two conductors constituting the balanced transmission line may be disposed in the vacuum chamber, and the other. conductor may be disposed on an atmospheric pressure side outside the vacuum chamber. In this case, a gas passageway is formed in a dielectric supporting the balanced transmission line. Thus, the efficiency in ionization resulting in plasma can be improved.

[0027] If a conducting strip included in a microstrip is disposed in the vacuum chamber, the microstrip may be substituted for the balanced transmission line. In this case, a gas passageway is formed in a dielectric plate. A structure having a wire disposed in a space above a grounded conducting plane may be adopted as the microstrip. In this case, the space on the grounded conducting plane and the wire are disposed in a vacuum chamber, and a gas is introduced into the space between the grounded conducting plane and wire. This results in a simplified configuration.

Problems solved by technology

It is hard to generate a uniform electromagnetic field.

This poses a problem in that it is hard to attain an impedance match relative to the spiral coil through which a high-frequency wave is propagated.

It is hard to generate a uniform electromagnetic field.

Consequently, it is hard to generate a uniform electromagnetic field in a planar direction.

It is difficult to adapt such antenna to a process chamber.

Moreover, a radiated electromagnetic wave reflects from or interferes with the wall surface of the process chamber.

It is difficult to control for generating a desired electromagnetic field.

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