US 7,094,315 B2 · Chamber configuration for confining a plasma

Abstract

A plasma confining assembly for minimizing unwanted plasma formations in regions outside of a process region in a process chamber is disclosed. The plasma confining assembly includes a first confining element and second confining element positioned proximate the periphery of the process region. The second confining element is spaced apart from the first confining element. The first confining element includes an exposed conductive surface that is electrically grounded and the second confining element includes an exposed insulating surface, which is configured for covering a conductive portion that is electrically grounded. The first confining element and the second confining element substantially reduce the effects of plasma forming components that pass therebetween. Additionally, the plasma confining assembly may include a third confining element, which is formed from an insulating material and disposed between the first confining element and the second confining element, and proximate the periphery of the process region. The third confining element further reduces the effects of plasma forming components that pass between the first confining element and the second confining element.

Drawings

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Drawings

Claims27

Dependent claims

A plasma reactor for processing a substrate, comprising:

a process chamber having chamber walls;
an electrode arrangement configured for generating an electric field to both ignite and sustain a plasma for the processing within the chamber, the arrangement comprising a first electrode and a second electrode which is spaced apart from the first electrode, the first electrode and the second electrode defining a process region therebetween;
and
a plasma confining assembly for minimizing unwanted plasma formations in regions outside of the process region in the process chamber, comprising:
a first confining element positioned proximate the periphery of the process region, and including a conductive surface that is electrically grounded and exposed to said process region;
and
a second confining element positioned proximate the periphery of the process region, and including an exposed insulating surface, which is configured to at least partially cover a non-exposed conductive core that is electrically grounded, the second confining element being spaced apart from the first confining element such that one of the confining elements is disposed in an upper portion of the process chamber and the other confining element is disposed in a lower portion of the process chamber,
wherein the first confining element and the second confining element substantially reduces the effects of plasma forming components that pass therebetween.

5 more elements

A plasma reactor for processing a substrate, comprising:

a process chamber having chamber walls;
an electrode arrangement configured for generating an electric field to both ignite and sustain a plasma for the processing within the chamber, the arrangement comprising a first electrode and a second electrode which is spaced apart from the first electrode, the first electrode and the second electrode defining a process region therebetween;
and
a plasma confining assembly, comprising:
a first confining element positioned at a boundary between the process region where a plasma is ignited and sustained for processing a work piece and the regions outside of the process region where the plasma is not desired, the first confining element including a conductive member that is exposed within the process chamber to said process region, the conductive member being electrically grounded;
and
a second confining element positioned at the boundary between the process region where the plasma is ignited and sustained for processing and the regions outside of the process region where the plasma is not desired, the second confining element including an insulating portion that is exposed within the process chamber, and a conductive portion that is covered by the insulating portion so as to keep the conductive portion from being exposed inside the process chamber, the conductive member being electrically grounded,
the second confining element being spaced apart from the first confining element so as to form an open area therebetween that permits by-product gases to pass therethrough from the process region to the regions outside of the process region while substantially preventing charged particles or electric fields from passing therethrough from the process region to the regions outside of the process region,
wherein the first confining element is formed as a first ring configured to surround a first electrode, and wherein the second confining element is formed as a second ring configured to surround a second electrode that is spaced apart and parallel to the first electrode, the first and second electrodes defining the process region therebetween, the first and second electrodes being configured for generating an electric field that is sufficiently strong to both ignite and sustain the plasma in the process region of the process chamber.

6 more elements

Dependencies are inferred from the claim text.

Description8,529 words

Summary1,033 words

#The present invention relates to apparatus and methods for processing substrates such as semiconductor substrates for use in IC fabrication or glass panels for use in flat panel display applications. More particularly, the present invention relates to improved techniques for controlling plasma formation in a process chamber of a plasma reactor.

#The use of plasma-enhanced processes in the manufacture of semiconductor-based products (such as integrated circuits or flat panel displays) is well known. In general, plasma-enhanced processes involve processing a substrate in a process chamber of a plasma reactor. In most plasma reactors, a plasma may be ignited and sustained by supplying a gas containing appropriate etchant or deposition source gases into the process chamber and applying energy to those source gases to respectively etch or deposit a layer of material on the surface of the substrate. By way of example, capacitive plasma reactors have been widely used to process semiconductor substrates and display panels. In capacitive plasma reactors, a capacitive discharge is formed between a pair of parallel electrodes when RF power is applied to one or both of the electrodes.

#Although the plasma predominantly stays in the process area between the pair of electrodes, portions of the plasma may fill the entire chamber. A plasma typically goes where it can be sustained, which is almost anywhere in the chamber. By way of example, the plasma may fill the areas outside the process region such as the bellows of the pumping arrangement. If the plasma reaches these areas, etch, deposition and/or corrosion of the areas may ensue, which may lead to particle contamination inside the process chamber, and/or which may reduce the lifetime of the chamber or chamber parts. Furthermore, a non-confined plasma may form a non uniform plasma, which may lead to variations in process performance.

Brief description of the drawings7 figures

#The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:

#FIG. 1 illustrates a plasma reactor, in accordance with one embodiment of the present invention.

#FIG. 2 shows a broken away view of the plasma reactor of FIG. 1, in accordance with one embodiment of the present invention.

Detailed description7,351 words

#The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.

#It has been discovered that unwanted discharges or plasmas may be encountered when large charged particle fluxes and/or large electric fields are present in regions outside of the process region of the process chamber. As the term is employed herein, the process region refers to the region of the process chamber used for processing a substrate, for example, the area directly above the substrate. With regards to charged particles, charged particles leaving the process region may collide with the wall of the process chamber, and as a result generate secondary electrons that can ignite and/or sustain a plasma. With regards to the electric field, an electric field can accelerate the electrons causing them to collide with the gas molecules of the process gas, which as a result can ionize and initiate a plasma. In addition, charged particles tend to follow the electric field lines and thus stray electric field lines may guide more charged particles into regions outside of the process region of the process chamber. For example, electric fields can accelerate charged particles in a direction towards the walls of the process chamber. This acceleration and subsequent collision between the charged particles and the chamber walls may generate secondary electrons, which may ignite and/or sustain a plasma.

#The invention therefore pertains to an improved method and apparatus for confining a plasma to a process region of a process chamber. More particularly, the invention pertains to a system for minimizing and/or eliminating unwanted discharges (or plasma formations) in regions outside of the process region of the process chamber. For ease of discussion, the regions outside of the process region will herein be referred to as the outer regions of the process chamber. One aspect of the invention relates to reducing the density of charged particles in the outer regions of the process chamber. For example, by absorbing particles on surfaces before they reach the outer regions or by not allowing the particles to pass to the outer regions. Another aspect of the invention relates to attenuating the electric field (used to form the plasma) in the outer regions of the process chamber. For example, by directing electric fields away from the outer regions. The invention is particularly useful in plasma processing systems that utilize capacitive discharges to form the plasma.

Facts

Application

11/022,396Filed 22 Dec 2004 · division

Priority

28 Sep 2000

Published

US 2005/0103442 A119 May 2005

Granted

22 Aug 2006

Term ended

28 Sep 2020

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification4 codes

H01J 37/32871
Hygiene: means for trapping or directing unwanted particles
H01J 37/32082
Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources: radio frequency generated…
H01J 37/32623
Constructional details of the reactor: mechanical discharge control means
H01J
Electric discharge tubes or discharge lamps

Chamber configuration for confining a plasma

Life of this patent

Chamber configuration for confining a plasma

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims27

Description8,529 words

Drawings

Classification4 codes

Life of this patent

Description8,529 words