Chemistry: electrical and wave energy – Apparatus – Coating – forming or etching by sputtering
Reexamination Certificate
2000-04-10
2001-06-26
Nguyen, Nam (Department: 1753)
Chemistry: electrical and wave energy
Apparatus
Coating, forming or etching by sputtering
C204S298060, C204S298340, C156S345420, C118S7230IR
Reexamination Certificate
active
06251241
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of semiconductor device manufacturing and, more particularly to an inductive-coupled plasma apparatus employing a capacitive shield to reduce sputter contamination and a method for manufacturing the shield.
2. Description of the Background Art
The uniform and rapid processing of materials using induction generated, plasma-based processes (also referred to as inductive-coupled plasma processes) is important in the fields of semiconductor device manufacturing, packaging, optics, and the like. Many plasma processes are extensively used for the depositing or reactive etching of layers during semiconductor device fabrication. Especially, a radio frequency (RF at about 13.56 MHz ) induction plasma source is known to produce high electron density plasma, thus providing high processing rates.
For example, a semiconductor substrate is disposed within an evacuated chamber coupled to a source of plasma. By appropriately biasing the substrate, the plasma is coupled to the substrate for ion bombarding the substrate, for etching patterns in the substrate, or for depositing ions on the substrate to grow layers of selected materials thereon.
Hereinafter a conventional inductive-coupled plasma apparatus
10
shown in FIG.
1
and
FIG. 2
is explained in detail. The conventional inductive-coupled plasma apparatus includes a process chamber
20
and a RF housing
40
which is often called a match box. The process chamber
20
includes a supporter
22
for supporting at least one semiconductor wafer
28
, an edge ring
24
surrounding the supporter
22
and a gas injection ring
26
for injecting gas into the process chamber
20
. Also the process chamber
20
further includes a pump
30
for controlling a pressure of an inner space of the process chamber
20
.
A spiral coil
44
shown in
FIG. 2
is coupled to the RF housing
40
. Power is supplied from RF power supply line
48
to the spiral coil
44
. The spiral coil
44
is supported by a coil holder
46
, which is fixed to the RF housing
40
through a rod
80
. The spiral coil
44
is separated from the plasma by a planar dielectric window
42
.
However, in this conventional apparatus, high potentials on the coil cause some degree of capacitive coupling. Therefore, some particular regions, especially regions located underneath the coil on the surface of the planar dielectric window, are etched more excessively than other regions. Thus the etching process is contaminated due to falling particles from the etched regions of the planar dielectric window.
A technique is thus desired for maintaining high inductive coupling between the coil and the plasma, so that improved processing rates and reduction of sputtered contaminates from the dielectric window may be realized.
SUMMARY OF THE INVENTION
The present invention is therefore directed to an inductive coupled plasma apparatus which substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art.
It is therefore an object of the present invention to provide an apparatus for maintaining high inductive coupling and reducing sputtered contaminates from the dielectric window.
The present invention is directed to an apparatus for enhanced inductive coupling to plasma with reduced sputter contamination. The present invention eliminates sputtering of the dielectric window generated by high potentials on the adjacent spiral like or helical coil by adding a shield between the dielectric window and the coil.
The shields of the present invention are designed so that they do not interfere with the inductive coupling of the coil to the plasma, but interfere with the capacitive electric fields generated by the coil.
A primary advantage of the shield of the present invention is the reduction or elimination of sputtered contaminants from the dielectric vacuum window.
In order to attain the above objects, according to an aspect of the present invention, there is provided an apparatus for generating a high-density plasma, which includes a process chamber having a dielectric window located along a plane, a coil located outside the process chamber proximate the dielectric window and substantially parallel to the plane and a capacitive shield located between the coil and the dielectric window, wherein the shield has multiple openings, and wherein the multiple openings of the shield are disposed at locations corresponding to areas between the coil.
In the apparatus according to the invention, the coil may be spiral-shaped and the dielectric window and the shield may be substantially flat, and each of the multiple openings of the shield may be concentric-shaped.
Furthermore, the shield may further include a portion extending outwardly and the apparatus may further include a shield holder for supporting the shield by coupling the portion extending outwardly.
Still further, in the apparatus, the coil may be helical-shaped, the dielectric window and the shield may be disposed concentrically within the coil, and the shield may have a number of helically extending and circumferentially spaced openings.
Still further, in the apparatus, the shield may be made of an aluminum metal or a copper metal, and a surface of the shield may be coated with a silver.
According to another aspect of this invention, there is provided a method of manufacturing a shield of an apparatus for generating a high-density plasma using a coil and having a dielectric window, the method including carrying out an etching process using the plasma, examining a characteristic pattern of etched portions of the surface of the dielectric window, designating first portions to be etched and second portions to be deposited, manufacturing the shield having a first portion corresponding to first portions of the dielectric window and a second portion to be opened corresponding to second portions of the dielectric window, and disposing the second portion of the shield at locations corresponding to areas between the coil.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 5234529 (1993-08-01), Johnson
patent: 5800688 (1998-09-01), Lantsman et al.
patent: 607797 (1994-07-01), None
Cha Hun
Choi Baik-soon
Kim Jin-man
Shin Eun-hee
Jones Volentine, L.L.C.
Nguyen Nam
Samsung Electronics Co,. Ltd.
VerSteeg Steven H.
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