KR20080070125A - Inductively coupled plasma reactor - Google Patents

Abstract

An inductively coupled plasma reactor is provided to preclude electrostatic bonding between wireless frequency antennas of a plasma reactor and shower heads in a vacuum chamber by mounting discharge preventing walls along an edge of the opening of a dielectric window and to obtain high magnetic flux transfer efficiency by a magnetic core cover. An inductively coupled plasma reactor comprises a vacuum chamber(10), a dielectric window(32), gas shower heads(20), wireless frequency antennas(30), magnetic core covers(31), and discharge preventing walls(50). The vacuum chamber has a substrate supporter(12) on which a processed substrate(13) is laid. An opening is formed at the center of the dielectric window. The gas shower heads are installed at the opening of the dielectric window. The wireless frequency antennas are installed around the gas shower heads. The magnetic core covers are placed on the dielectric window. The discharge preventing walls are mounted along an edge of the opening. The discharge preventing walls are made of ceramic.

Description

Inductively Coupled Plasma Reactor {INDUCTIVELY COUPLED PLASMA REACTOR}

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a cross-sectional view of an inductively coupled plasma reactor according to a preferred embodiment of the present invention.

FIG. 2 is a perspective view of the discharge preventing wall of FIG. 1 viewed from below. FIG.

3 is a cross-sectional view of an inductively coupled plasma reactor according to a variation of the present invention.

FIG. 4 is a perspective view of the discharge preventing wall of FIG. 3 viewed from below. FIG.

* Description of the symbols for the main parts of the drawings *

10: vacuum chamber 11: chamber body

12: substrate support 13: substrate to be processed

14 gas outlet 20 shower head

21: gas distribution plate 30: radio frequency antenna

31: Magnetic core cover 32: Dielectric window

33: top cover 40: first power supply source

41: impedance matcher 42: second power source

43: third power source 44: impedance matcher

50: discharge barrier

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductively coupled plasma reactor using radio frequency. Specifically, the present invention relates to an induction that can generate a high density plasma having a higher uniformity and a more uniform control of plasma ion energy. A coupled plasma reactor.

Plasma is a highly ionized gas containing the same number of positive ions and electrons. Plasma discharges are used for gas excitation to generate active gases containing ions, free radicals, atoms, molecules. The active gas is widely used in various fields and is typically used in a variety of semiconductor manufacturing processes such as etching, deposition, cleaning, ashing, and the like.

There are a number of plasma sources for generating plasma, and the representative examples are capacitive coupled plasma and inductive coupled plasma using radio frequency.

Capacitively coupled plasma sources have the advantage of high process productivity compared to other plasma sources due to their high capacity for precise capacitive coupling and ion control. On the other hand, since the energy of the radio frequency power supply is almost exclusively connected to the plasma through capacitive coupling, the plasma ion density can only be increased or decreased by increasing or decreasing the capacitively coupled radio frequency power. However, increasing radio frequency power increases ion bombardment energy. As a result, in order to prevent damage caused by ion bombardment, there is a limit of radio frequency power supplied.

On the other hand, the inductively coupled plasma source can easily increase the ion density with the increase of the radio frequency power source, the ion bombardment is relatively low, it is known to be suitable for obtaining a high density plasma. Therefore, inductively coupled plasma sources are commonly used to obtain high density plasma. Inductively coupled plasma sources are typically developed using a radio frequency antenna (RF antenna) and a transformer (also called transformer coupled plasma). The development of technology to improve the characteristics of plasma, and to increase the reproducibility and control ability by adding an electromagnet or a permanent magnet or adding a capacitive coupling electrode.

Radio frequency antennas are generally used as spiral type antennas or cylinder type antennas. The radio frequency antenna is disposed outside the plasma reactor and transmits induced electromotive force into the plasma reactor through a dielectric window such as quartz. Inductively coupled plasma using a radio frequency antenna can obtain a high density plasma relatively easily, but the plasma uniformity is affected by the structural characteristics of the antenna. Therefore, efforts have been made to improve the structure of the radio frequency antenna to obtain a uniform high density plasma.

However, in order to obtain a large plasma, it is limited to widen the structure of the antenna or increase the power supplied to the antenna. For example, it is known that a non-uniform plasma is generated in the radiographic state by a standing wave effect. In addition, when high power is applied to the antenna, the capacitive coupling of the radio frequency antenna increases, so that the dielectric window must be thickened, thereby increasing the distance between the radio frequency antenna and the plasma, thereby lowering power transmission efficiency. Losing problems occur. In the case of an inductively coupled plasma reactor having a radio frequency antenna, an electrostatic coupling may be generated between the radio frequency antenna of the inductively coupled plasma reactor and an electrode (shower head) inside the vacuum chamber, resulting in uneven plasma density.

In the recent semiconductor manufacturing industry, plasma processing technology has been further improved due to various factors such as ultra-miniaturization of semiconductor devices, the enlargement of silicon wafer substrates for manufacturing semiconductor circuits, the enlargement of glass substrates for manufacturing liquid crystal displays, and the emergence of new target materials. This is required. In particular, there is a need for improved plasma sources and plasma processing techniques that have good processing capabilities for large area workpieces.

An object of the present invention is to prevent electrostatic coupling between the radio frequency antenna of the inductively coupled plasma reactor and the electrode (shower head) inside the vacuum chamber, thereby preventing the plasma density from being uneven, and improving the flux transfer efficiency, thereby making it more uniform. An inductively coupled plasma reactor capable of generating a large area of high density plasma is provided.

One aspect of the present invention for achieving the above technical problem relates to an inductively coupled plasma reactor. An inductively coupled plasma reactor of the present invention comprises: a vacuum chamber having a substrate support on which a substrate to be processed is placed; A dielectric window installed at an upper portion of the vacuum chamber and having an opening at a central portion thereof; A gas shower head installed in the opening of the dielectric window; A radio frequency antenna installed above the gas shower head above the dielectric window; A magnetic core cover installed on an upper portion of the dielectric window to cover the radio frequency antenna; And a discharge preventing wall mounted along the edge of the opening in the vacuum chamber.

In one embodiment, the discharge preventing wall is made of a ceramic material.

In one embodiment, the bottom face of the gas shower head exposed into the vacuum chamber has either the same or lower position as the dielectric window.

In one embodiment, the substrate support is biased by receiving one or more bias power sources by one or more bias power sources.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the embodiments of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description. In understanding the drawings, it should be noted that like parts are intended to be represented by the same reference numerals as much as possible. And detailed description of known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention is omitted.

(Example)

Hereinafter, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention, the inductively coupled plasma reactor of the present invention will be described in detail.

1 is a cross-sectional view of an inductively coupled plasma reactor according to a preferred embodiment of the present invention, and FIG. 2 is a perspective view from below of the discharge preventing wall of FIG. 1.

1 is a cross-sectional view of an inductively coupled plasma reactor according to a preferred embodiment of the present invention, and FIG. 2 is a plan view of the radio frequency antenna of FIG.

1 and 2, the inductively coupled plasma reactor of the present invention includes a vacuum chamber 10 having a chamber body 11 and an upper cover 33 covering the ceiling of the chamber body 11. The substrate support 16 on which the substrate to be processed W is placed is provided in the vacuum chamber 100. The substrate W to be processed is, for example, a silicon wafer substrate for producing a semiconductor device or a glass substrate for producing a liquid crystal display or a plasma display. The inner side of the vacuum chamber 10 is provided with a dielectric window 32 having a central opening. The gas shower head 20 is installed in the opening of the dielectric window 32. The lower end of the chamber body 11 is provided with a gas outlet 14 for gas exhaust. The gas outlet 14 is connected to a vacuum pump (not shown).

The chamber body 11 is made of a metallic material such as aluminum, stainless steel or copper. Or coated metal, for example anodized aluminum or nickel plated aluminum. Or refractory metal. Alternatively, it is also possible to rewrite the chamber body 11 entirely with an electrically insulating material such as quartz, ceramic, or other materials suitable for carrying out the intended plasma process. Dielectric window 32 is comprised of an insulating material, such as, for example, quartz or ceramic.

The radio frequency antenna 30 is installed above the dielectric window 32. The radio frequency antenna 30 has a flat spiral structure in the region of the dielectric window 32. The radio frequency antenna 30 is covered by a magnetic core cover 31. The magnetic core cover 31 is installed so that the vertical cross-sectional structure has a horseshoe shape and is covered along the radio frequency antenna 30 so that the magnetic flux entrance and exit is directed toward the dielectric window 32. Therefore, the magnetic field generated by the radio frequency antenna 30 can minimize the loss of the magnetic flux since the magnetic flux is focused by the magnetic core cover 31. The electric field induced by the magnetic field transferred to the inner top of the vacuum chamber 10 is generated essentially parallel to the dielectric window 32.

The magnetic core cover 31 is made of ferrite but may be made of other alternative materials. Magnetic core cover 31 may be configured by assembling a plurality of horseshoe-shaped ferrite core pieces. Alternatively, an integrated ferrite core may be used. In the case of using a plurality of pieces, each piece can be connected by inserting a nonmagnetic material layer such as an insulating material on the assembly surface. Although the cooling water supply channel is not illustrated in detail, for example, the cooling water supply channel may be provided between the radio frequency antenna 30 and the magnetic core cover 31.

The gas shower head 20 provided in the opening of the dielectric window 32 has one or more gas distribution plates 21 and is connected to a gas supply source (not shown) through the gas inlet 22. The gas shower head 20 is provided inside the vacuum chamber 10 of the discharge preventing wall 50 for preventing the electrostatic coupling with the radio frequency antenna 30. The discharge preventing wall 50 is provided along the edge of the opening of the dielectric window 32 in the vacuum chamber 10. The discharge preventing wall 50 is comprised using a ceramic material.

The radio frequency antenna 30 is connected to a first power supply 40 which supplies a radio frequency through an impedance matcher 41. The substrate support 12 is electrically connected and biased through the impedance matcher 44 to the second and third power sources 42 and 43 for supplying different radio frequencies. The second and third power sources 54, 55 supply different radio frequencies to the substrate support 12. The dual bias structure of the substrate support 12 makes it easier to generate plasma inside the vacuum chamber 10, and further improve plasma ion energy control on the surface of the substrate W to further improve process productivity. have. The second and third power sources 42 and 43 may be configured using a radio frequency power source capable of controlling the output voltage without a separate impedance matcher. The substrate support 12 has a double bias structure, but may have a single bias structure by one power supply.

Process gas is injected into the vacuum chamber through the gas shower head 20, and when the radio frequency power is supplied from the first power source 40 to the radio frequency antenna 30, plasma is generated inside the vacuum chamber 10. Is generated. Since the radio frequency antenna 30 is installed around the gas shower head 20, the plasma density may be substantially improved in the edge region of the substrate support 12. The anti-discharge wall 50 blocks the electrostatic coupling that may occur between the radio frequency antenna 30 and the shower head 20 to prevent the plasma from being unevenly generated. In addition, magnetic flux transfer efficiency is improved by the magnetic core cover 31 to generate a more uniform high-density plasma.

3 is a cross-sectional view of an inductively coupled plasma reactor according to a modification of the present invention, and FIG. 4 is a perspective view of the discharge preventing wall of FIG. 3 viewed from below.

3 and 4, the inductively coupled plasma reactor of the modification has the same configuration as the above-described embodiment. However, the bottom surface of the gas shower head 20 exposed to the inside of the vacuum chamber 10 is installed lower than the dielectric window 32. In this case, the distance between the gas shower head 20 and the substrate support can be made narrower, and the correction coupling efficiency can be increased.

Embodiments of the inductively coupled plasma reactor of the present invention described above are merely illustrative, and those skilled in the art to which the present invention pertains may various modifications and equivalent other embodiments. You will know. Therefore, it is to be understood that the present invention is not limited to the specific forms mentioned in the above description. Therefore, the true technical protection scope of the present invention should be defined by the technical spirit of the appended claims, and the present invention is intended to cover all modifications, equivalents, and substitutes within the spirit and scope of the present invention as defined by the appended claims. It should be understood to include.

According to the inductively coupled plasma reactor of the present invention as described above, the electrostatic coupling between the radio frequency antenna of the plasma reactor and the electrode (shower head) inside the vacuum chamber is prevented from occurring by the discharge preventing wall, and the magnetic core cover As a result, the magnetic flux transfer efficiency is improved to generate a more uniform high-density plasma.

Claims (4)

A vacuum chamber having a substrate support on which a substrate to be processed is placed; A dielectric window installed at an upper portion of the vacuum chamber and having an opening at a central portion thereof; A gas shower head installed in the opening of the dielectric window; A radio frequency antenna installed above the gas shower head above the dielectric window; A magnetic core cover installed on an upper portion of the dielectric window to cover the radio frequency antenna; And An inductively coupled plasma reactor comprising a discharge preventing wall mounted along an edge of the opening in the vacuum chamber. 2. The inductively coupled plasma reactor as recited in claim 1, wherein said discharge barrier is comprised of a ceramic material. The inductively coupled plasma reactor of claim 1, wherein the bottom surface of the gas shower head exposed into the vacuum chamber is at one of the same or lower positions than the dielectric window. The inductively coupled plasma reactor of claim 1, wherein the substrate support is biased by receiving one or more bias power sources by one or more bias power sources.

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