KR102589743B1 - Plasma chamber having gas distribution plate for uniform gas distribution - Google Patents

Abstract

The present invention relates to a plasma chamber comprising a gas distribution plate for uniform gas distribution. The plasma chamber including a gas distribution plate for uniform gas distribution of the present invention includes a plasma chamber formed by combining a plurality of chamber blocks with a hollow discharge space; a gas distribution plate located on an upper chamber block in the plasma chamber and flowing supplied gas into the discharge space; a plurality of through holes provided in the gas distribution plate for flowing the supplied gas into the discharge space; and an ignition device provided on the gas distribution plate to cause initial ignition of plasma into the discharge space. According to the plasma chamber including a gas distribution plate for uniform gas distribution of the present invention, gas can be uniformly supplied into the plasma chamber. Therefore, plasma can be generated uniformly within the plasma channel, thereby improving plasma stability. Additionally, since the ignition electrode is not directly exposed to the plasma discharge space, it is possible to prevent particles from being generated by the ignition electrode.

Description

Plasma chamber including a gas distribution plate for uniform gas distribution {PLASMA CHAMBER HAVING GAS DISTRIBUTION PLATE FOR UNIFORM GAS DISTRIBUTION}

The present invention relates to a plasma chamber including a gas distribution plate for uniform gas distribution, and more specifically, to a plasma chamber including a gas distribution plate for uniform gas distribution that reacts with plasma to generate and discharge an activated gas. It's about the chamber.

Plasma discharges can be used to excite gases to produce activated gases containing ions, free radicals, atoms, and molecules. Activated gases are used in a variety of industrial and scientific applications, including processing solid materials such as semiconductor wafers, powders, and other gases. The parameters of the plasma and the conditions regarding its exposure to the materials being processed vary widely depending on the field of technology. For example, some fields require that ions be used with low kinetic energies (i.e., a few electron volts) because the materials being processed are susceptible to damage. Other applications, such as anisotropic etching or planarized insulator deposition, require the use of ions with high kinetic energy. Other applications, such as reactive ion beam etching, require precise control of ion energy.

Some fields require direct exposure of the material being processed to high density plasma. One of these fields is generating ion-activated chemical reactions. Other such areas include the etching of high aspect ratio structures and material deposition therein. Other fields require a neutral activated gas containing atoms and activated molecules, while the material being processed is shielded from the plasma, because the material is susceptible to damage by ions or because the processing process has high selectivity requirements. do.

Various plasma sources can generate plasma in a variety of ways, including DC discharge, radio frequency (RF) discharge, and microwave discharge. DC discharge is achieved by applying an electric potential between two electrodes in a gas. RF discharge is achieved by electrostatic or inductive coupling of energy from a power source into the plasma. Parallel plates are commonly used to inductively couple energy into a plasma. Induction coils are commonly used to induce electric current in a plasma. Microwave discharge is achieved by coupling microwave energy directly through a microwave pass-through window into a discharge chamber containing the gas. Microwave discharge can be used to support a wide range of discharge conditions, including highly ionized electron cyclone resonance (ECR) plasmas.

Compared to microwave or other types of RF plasma sources, toroidal plasma sources have advantages in low electric fields, low plasma chamber corrosion, compactness, and cost effectiveness. Toroidal plasma sources operate at low electric fields and inherently eliminate the current-termination electrode and associated cathode potential drop. Low plasma chamber corrosion allows toroidal plasma sources to operate at higher power densities than other plasma sources. Additionally, by using a high-permeability ferrite core to efficiently couple electromagnetic energy to the plasma, the toroidal plasma chamber can operate at relatively low RF frequencies, lowering power supply costs. Toroidal plasma chambers have been used to generate chemically active gases containing fluorine, oxygen, hydrogen, nitrogen, etc. for the processing of semiconductor wafers, flat panel displays, and various materials.

The gas supplied through the gas inlet of the toroidal plasma chamber moves along the toroidal plasma channel inside the chamber and reacts with plasma to generate activated gas. The flow of gas within the plasma chamber acts as an impedance. Since the gas supplied into the plasma chamber is mainly supplied through one inlet, it is not evenly distributed on both sides of the toroidal-shaped plasma channel. Therefore, a problem occurred in which the discharge was not uniform within the plasma channel.

The purpose of the present invention is to provide a plasma chamber including a gas distribution plate for uniform gas distribution that can uniformly generate plasma discharge within the plasma chamber by uniformly distributing the gas supplied into the plasma chamber.

One aspect of the present invention for achieving the above technical problem relates to a plasma chamber including a gas distribution plate for uniform gas distribution. The plasma chamber including a gas distribution plate for uniform gas distribution of the present invention includes a plasma chamber formed by combining a plurality of chamber blocks with a hollow discharge space; a gas distribution plate located on an upper chamber block in the plasma chamber and flowing supplied gas into the discharge space; a plurality of through holes provided in the gas distribution plate for flowing the supplied gas into the discharge space; and an ignition device provided on the gas distribution plate to cause initial ignition of plasma into the discharge space.

In one embodiment, the gas distribution plate includes an upper distribution area having a concave upper surface; and a lower distribution area that has a concave lower surface and forms part of the discharge space.

In one embodiment, the plasma chamber is connected to a lower distribution area of the gas distribution plate and includes an ignition connection path in which the ignition device is installed to face the lower distribution area.

In one embodiment, the gas distribution plate is provided around the upper distribution area and the lower distribution area and includes a cooling line through which coolant flows.

According to the plasma chamber including a gas distribution plate for uniform gas distribution of the present invention, gas can be uniformly supplied into the plasma chamber. Therefore, plasma can be generated uniformly within the plasma channel, thereby improving plasma stability. Additionally, since the ignition electrode is not directly exposed to the plasma discharge space, it is possible to prevent particles from being generated by the ignition electrode.

1 is an overall perspective view of a plasma source according to a preferred embodiment of the present invention.
FIG. 2 is an overall perspective view of the plasma chamber provided in the plasma source of FIG. 1.
FIG. 3 is a cross-sectional view of the plasma chamber of FIG. 2.
4 and 5 are partial cross-sectional views showing the upper part of the plasma chamber.
Figure 6 is a perspective view showing a gas distribution plate.
Figure 7 is a plan view showing the lower surface of the gas distribution plate.
Figure 8 is a plan view showing the top surface of the gas distribution plate.
9 and 10 are plan and cross-sectional views showing another embodiment of a gas distribution plate.
Figures 11 and 12 are cross-sectional views and exploded perspective views showing the ignition electrode unit.

In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. 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 to the embodiments described in detail below. This example is provided to more completely explain the present invention to those with average knowledge in the art. Therefore, the shapes of elements in the drawings may be exaggerated to emphasize a clearer description. It should be noted that the same configuration may be indicated by the same reference numeral in each drawing. Detailed descriptions of well-known functions and configurations that are judged to unnecessarily obscure the gist of the present invention are omitted.

FIG. 1 is an overall perspective view of a plasma source according to a preferred embodiment of the present invention, FIG. 2 is an overall perspective view of a plasma chamber provided in the plasma source of FIG. 1, and FIG. 3 is a cross-sectional view of the plasma chamber of FIG. 2.

1 to 3, the preferred plasma source 10 of the present invention has a transformer coupled plasma source structure in which a plasma chamber 20 and a transformer 30 are coupled. In this embodiment, the main plasma source mounted on the plasma reactor exemplifies a transformer-coupled plasma source, but various types of plasma sources may be employed.

The plasma chamber 20 has a chamber block 22 forming a toroidal-shaped plasma discharge channel 21. The chamber block 22 includes one or more insulating brakes 29 when made of conductive material. If the chamber block 22 is made of a non-conductive material, it is not provided with an insulating brake 29. The process chamber 20 is contained in an external case 19 and forms a plasma source 10. The plasma source 10 serves to supply activated gas to a process chamber (not shown). One or more sides of the plasma chamber 20 are exposed to the process chamber (not shown) so that charged particles generated by the plasma are in direct contact with the material to be processed (not shown). Optionally, the plasma chamber 20 is located at a distance from the process chamber to allow activated gas to flow into the process chamber. The susceptor may be located within the process chamber to support a material to be processed, for example, a substrate to be processed. The material to be treated may be biased relative to the potential of the plasma.

Transformer 30 includes one or more ferrite cores 32 and a primary winding (not shown) coil wound around the ferrite core 32. The ferrite core 32 is mounted surrounding a portion of the chamber block 22 so as to be linked to the chamber discharge channel 21. A primary winding (not shown) coil is wound on the ferrite core 32. The primary winding coil is connected to a power source (not shown). When power is supplied from the power source to the primary winding, plasma is generated in the discharge space within the plasma discharge channel 21. The plasma generated in the plasma discharge channel 21 is connected to the transformer. It forms the secondary side of the chamber block 22. The chamber block 22 has a gas inlet 24 for supplying gas to the plasma discharge channel 21 and a gas inlet 24 for reacting gas and plasma to discharge the activated gas into a process chamber (not shown). A gas outlet 26 is provided for.

The chamber block 22 is divided into a plurality of blocks, and the divided blocks are combined to form the plasma chamber 20. O-rings (not shown) are included and connected between multiple blocks. A plurality of blocks are combined to form a toroidal-shaped plasma discharge channel 21. The upper area of the plasma discharge channel 21 is composed of a first chamber block 20a to which gas is supplied, a gas distribution plate 40, and a second chamber block 20b. It includes a third chamber block 20c that forms a middle region through which gas moves vertically in the plasma discharge channel 21, and a fourth chamber block 20d that forms a lower region of the plasma discharge channel 21. A separate fifth chamber block 20e provided with a gas outlet 26 may be formed separately.

The first chamber block 20a is provided with a gas inlet 24 for gas supply at the upper center. The gas supplied to the gas inlet 24 flows along the gas supply channel 23, where the gas inlet 24 is a gas manifold installed outside the plasma source 10 through the gas supply block 16. 11). The gas supply path 13 connecting the gas manifold 11 and the gas inlet 24 is bent one or more times to control the flow rate of the supplied gas. The gas manifold 11 is separated from the coolant manifold 15, thereby preventing the temperature of the gas supplied by the coolant from decreasing.

The gas distribution plate 40 includes an ignition electrode unit 50 for initial ignition of plasma. The gas distribution plate 40 has a plurality of through holes 43 for distributing and supplying gas into the plasma discharge channel 21. ) is provided. The structure and effects of the gas distribution plate 40 and the ignition electrode unit 50 are described in detail below.

The second chamber block 20b is connected to the gas distribution plate 40 to form the upper part of the plasma discharge channel 21. A ferrite core 32 is installed in the third chamber block 20c. The ferrite core 32 may be installed in both of the third chamber blocks 20c, or may be installed in only one third chamber block 20c.

A gas outlet 26 is provided in the fifth chamber block 20e. The fifth chamber block 30e includes a channel outlet through which gas activated in the plasma discharge channel 21 is discharged to the gas outlet 26. Here, the channel outlet is formed to be smooth and inclined at a predetermined angle so that the activated gas can be smoothly discharged through the gas outlet 26.

4 and 5 are partial cross-sectional views showing the upper part of the plasma chamber.

Referring to Figures 4 and 5, the upper region in the present invention includes a first chamber block (20a) with a gas inlet (24) and a gas distribution plate for uniformly distributing the supplied gas to the plasma discharge channel (21). It consists of (40). The inside of the gas supply passage 13 may be bare or coated.

The gas distribution plate 40 includes an upper distribution area 42 and a lower distribution area 44 in which a space is formed in a concave shape, and a plurality of through holes 43 formed through the upper and lower distribution areas. The upper distribution area 42 and the lower distribution area 44 are formed in a concave shape and have a predetermined length on the upper surface of the gas distribution plate 40.

The flow rate of the gas injected through the gas inlet 24 is primarily reduced by the upper distribution area 42. The gas supplied to the upper distribution area 42 is uniformly distributed to the lower distribution area 44 through a plurality of through holes. At this time, since the lower distribution area 44 forms the upper part of the plasma discharge channel 21, the supplied gas is uniformly distributed into the plasma discharge channel 21.

The gas distribution plate 40 is provided with an ignition electrode unit 50 as an ignition device for generating free charges that provide an initial ionization event that ignites the plasma into the plasma discharge channel 21. The initial ionization event may be a short, high voltage pulse applied to the plasma chamber 110. Continuously high RF voltages can also be used to generate initial ionization events. Ultraviolet radiation may also be used to create free charges within the plasma channel 112, which provides an initial ionization event that ignites the plasma within the plasma channel 112. In another embodiment, ignition power is applied to the ignition electrode 122 located in the plasma chamber 100. In another embodiment, ignition power may be applied directly to primary winding 132 to provide an initial ionization event. In another embodiment, the plasma chamber 100 may be exposed to ultraviolet radiation from an ultraviolet light source (not shown) optically coupled to the chamber block 110 to trigger an initial ionization event that ignites the plasma.

The ignition electrode unit 50 is located at the center of the side of the gas distribution plate 40. The ignition electrode unit 50 is connected to a power supply (not shown) that supplies power for initial ignition of the plasma. The power source may be a separate source for supplying ignition power, or it may be a power source to which the primary winding is connected. The ignition electrode unit 50 and the lower distribution area 44 of the gas distribution plate 40 are connected by an ignition connection path 51. The gas distributed to the lower distribution area 44 is supplied to the ignition connection 51, and when the initial ionization event is performed by the ignition electrode unit 50, plasma is generated in the ignition connection 51 and the lower distribution area 44. Initial ignition takes place. Since the initial plasma ignition does not occur in the plasma discharge channel 21, it is possible to prevent the generation of particles due to damage to the inside of the chamber block 22 due to arc discharge during initial ignition. Here, the ignition connection path 51 is formed inclined at a predetermined angle with respect to the plasma discharge channel 21, so that the discharged plasma flows backstream along the ignition connection path 51 by the ignition electrode unit 50. Prevents particles from being generated.

FIG. 6 is a perspective view showing the gas distribution plate, FIG. 7 is a plan view showing the lower surface of the gas distribution plate, and FIG. 8 is a plan view showing the upper surface of the gas distribution plate.

Referring to Figures 6 to 8, the gas distribution plate 40 has an upper distribution area 42 and a lower distribution area 44 in which a space is formed in a concave shape, and a plurality of through holes formed through the upper and lower distribution areas. Includes (43). The upper distribution area 42 and the lower distribution area 44 are long in one direction and form the upper part of the toroidal-shaped plasma discharge channel 21.

A plurality of through holes 43 may be formed evenly distributed throughout the upper and lower distribution areas 42 and 44, and as shown in the figure, two third chamber blocks 20c are formed on both sides (when the blocks are combined). The first through hole 43b may be formed by focusing on the located portion. In addition, a second through-hole (43a) is formed in the part opposite to the part where the ignition electrode unit 50 is installed so that gas can be distributed to the plasma discharge channel 21. The plurality of through holes 43 may all be formed in the same size and shape, or may be formed in various sizes and shapes to uniformly distribute the gas. In one embodiment, the first through hole 43b is formed at an angle with respect to the plasma discharge channel 21 so that gas can pass through the gas in a spiral rotation and be rotated and supplied to the plasma discharge channel 21. Therefore, it is possible to prevent the gas supplied into the plasma discharge channel 21 from directly hitting the chamber block, damaging the chamber block and generating particles. Additionally, uniform gas distribution is possible through gas rotation, thereby improving the reaction between gas and plasma. Additionally, it is possible to prevent discharged plasma from flowing back.

The first and second through holes 43b and 43a may be formed perpendicular to the upper or lower surface of the gas distribution plate 40, or may be formed at an angle at a predetermined angle. In particular, the first through hole 43b is formed by being inclined at a predetermined angle. When the through hole 43 is formed at an angle, the supplied gas passes through the through hole 43 and is supplied while rotating into the plasma discharge channel 21. Therefore, the gas residence time within the plasma discharge channel 21 can be increased. The upper distribution area 42 of the gas distribution plate 40 is formed so that the two third chamber bodies 20c are located on both sides with deeper grooves than the central portion, so that gas can quickly flow to the third chamber body 20c. ensure that it can be supplied.

The gas distribution plate 40 is provided with a cooling line 45 inside the upper distribution area 42 and the lower distribution area 44 along the periphery. When coolant is supplied from a coolant source (not shown), the coolant supplied to the coolant inlet (59a) circulates along the cooling line (45) and then flows to the coolant outlet (59b) to overheat the gas distribution plate (40) by plasma discharge. lower the temperature. The cooling line 45 is formed along the circumference of the plasma discharge channel 21. In the present invention, the cooling line 45 provided in the gas distribution plate 40 is illustrated and explained, but the cooling line 45 is formed in the plasma chamber 20 along the plasma discharge channel 21. The gas distribution plate 40 has an O-ring 46 installed on its upper surface.

9 and 10 are plan and cross-sectional views showing another embodiment of a gas distribution plate.

Referring to Figures 9 and 10, the ignition electrode unit 50 can be installed directly toward the upper distribution area 42. Here, the ignition electrode unit 50 is installed in the upper distribution area 42, so that plasma discharge occurs in the upper distribution area 42 of the gas distribution plate 40, and plasma ions discharged into the plurality of through holes 43 This may be distributed.

Figures 11 and 12 are cross-sectional views and exploded perspective views showing the ignition electrode unit.

Referring to Figures 11 and 12, the ignition electrode unit 50 includes an ignition electrode 56 for initial ignition of plasma, an insulating plate 52 to prevent the ignition electrode 56 from being damaged by plasma, and an ignition electrode. It supports (56) and includes an electrode insulation portion (54) to be electrically insulated. The ignition electrode 56 is installed in an open portion of one side of the gas distribution plate 40. The insulating plate 52 is formed in a plate shape, and an electrode insulating portion 54 is installed on the top. The electrode insulation portion 54 is opened and the ignition electrode 56 is installed in the center, and is formed so that the periphery of the ignition electrode 56 can be mounted. An electrode cover 58 is installed outside the ignition electrode 56. An O-ring (not shown) for vacuum insulation is provided between the insulating plate 52 and the ignition electrode 56. The insulating plate 52 is made of sapphire, for example, and prevents the discharged plasma from flowing back and damaging the ignition electrode 56.

The embodiment of the plasma chamber including the gas distribution plate for uniform gas distribution of the present invention described above is merely illustrative, and those skilled in the art will recognize various modifications and variations therefrom. It will be appreciated that other equivalent embodiments are possible.

Thus, it will be understood that the present invention is not limited to the forms mentioned in the detailed description above. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims. In addition, the present invention should be understood to include all modifications, equivalents and substitutes within the spirit and scope of the present invention as defined by the appended claims.

10: Plasma source 11: Gas manifold
13: gas supply path 15: coolant manifold
20: plasma chamber 21: plasma discharge channel
22: Chamber block 24: Gas inlet
26: gas outlet 29: insulation brake
30: Transformer 32: Ferrite core
40: gas distribution plate 42: upper distribution area
43: through hole 43a: first through hole
43b: second through hole 44: lower distribution area
45: Cooling line 50: Ignition electrode unit
51: Ignition connection 52: Insulating plate
54: electrode insulation portion 56: ignition electrode
58: electrode cover

Claims (7)

A plasma chamber in which a discharge space is formed;
a gas distribution plate that distributes gas supplied within the plasma chamber to the discharge space;
A plurality of through holes formed in the gas distribution plate to provide supplied gas to the discharge space, and
An ignition device formed on the gas distribution plate to cause initial ignition of plasma into the discharge space,
The gas distribution plate is,
an upper distribution area formed on the upper surface for gas distribution; and
An area for gas distribution is formed on the lower surface, and a lower distribution area includes a portion of the discharge space,
The lower distribution area is
A plasma chamber further comprising a distribution area for distributing the gas and an ignition connection path connecting the ignition device. delete delete According to paragraph 1,
The gas distribution plate is,
Formed adjacent to one of the upper distribution area and the lower distribution area,
A plasma chamber further comprising a cooling line for lowering the temperature of the gas distribution plate. A plasma chamber in which a discharge space is formed;
a gas distribution plate that distributes gas supplied within the plasma chamber to the discharge space;
A plurality of through holes formed in the gas distribution plate to provide supplied gas to the discharge space, and
It includes an ignition device formed on the gas distribution plate to cause initial ignition of plasma into the discharge space,
The plurality of through holes are,
Further comprising a first through hole and a second through hole,
The first through hole is concentrated in an area adjacent to the discharge space and distributes gas,
The second through hole is concentrated in an area opposite the ignition device to distribute gas. According to paragraph 1,
The plurality of through holes are,
Plasma chambers characterized by being formed of the same size and shape, or formed of different sizes and shapes. According to paragraph 1,
A plurality of through holes formed in the upper distribution area and a plurality of through holes formed in the lower distribution area,
It is formed to penetrate vertically based on the joint surface between the gas distribution plates, or
A plasma chamber formed so that one side is inclined at a predetermined angle and penetrates.