KR20150143793A - Capacitively coupled plasma equipment with uniform plasma density - Google Patents

Abstract

The technique described herein includes an apparatus and a process for producing a plasma having a uniform electron density over the entire area of an electrode used for generating a plasma. The top electrode of the capacitively coupled plasma system may include structural features configured to assist in the generation of a uniform plasma. Such structural features define the surface shape at the surface facing the plasma. Such structural features may include a collection of concentric rings having a generally rectangular cross-section and protruding from the surface of the upper electrode. Such structural features may also include nested elongated protrusions having a predetermined cross-sectional size and shape, and the spacing of the protrusions is selected such that the system produces a plasma of uniform density. A dielectric member may be disposed over the structural feature to prevent or inhibit corrosion from the plasma while maintaining plasma uniformity.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a capacitive coupling type plasma apparatus having uniform plasma density,

Cross-reference to related application

This application claims priority to U.S. Patent Application No. 13 / 865,178, filed April 17, 2013, entitled " Capacitive Coupled Plasma Apparatus with Uniform Plasma Density, " All of which are incorporated herein by reference.

The present invention relates to plasma processing of workpieces including plasma processing using a capacitively coupled plasma system.

In the semiconductor device manufacturing process, plasma processing such as etching, sputtering, CVD (Chemical Vapor Deposition) and the like is routinely performed on a substrate to be processed, for example, a semiconductor wafer. Among the plasma processing apparatuses that execute such plasma processing, capacitively coupled parallel plate plasma processing apparatuses are widely used.

In the capacitively coupled parallel plate plasma processing apparatus, a pair of parallel plate electrodes (upper electrode and lower electrode) are disposed in the process chamber, and the process gas is introduced into the process chamber. By applying radio frequency (RF) power to at least one of the electrodes, a high frequency electric field is formed between the electrodes so that the plasma of the process gas is generated by the high frequency electric field. As a result, plasma processing is performed on the wafer by using or manipulating the plasma.

Plasma enhanced chemical vapor deposition (PECVD) as well as plasma etching of semiconductor wafers are generally performed using parallel plate capacitively coupled plasma tools. The semiconductor industry is moving toward using larger size wafers as well as fabricating narrower or smaller nodes (critical features) on wafers. For example, the industry is transitioning from working with 300 mm diameter wafers to working with 450 mm diameter wafers. As node sizes become smaller and wafers become larger, the macroscopic and microscopic uniformity of plasma and free radicals is becoming increasingly important in order to avoid defects in the processed wafers.

An important challenge in capacitively coupled plasma (CCP) systems is plasma non-uniformity. It is more preferable to use a very high frequency plasma (30-300 MHz) for wafer processing and a radio frequency (RF) plasma (3-30 MHz) for flat panel display processing. However, such high frequency plasma tends to be at least partially non-uniform due to standing waves generated in the plasma.

Conventional attempts to address the non-uniformity of CCP systems have involved the use of high temperature electrodes and phase control techniques with Gaussian lens structures. However, such attempts are complex and costly.

The techniques described herein include an upper electrode (hot electrode) of a capacitively coupled plasma system having structural features configured to assist in uniform plasma generation. Such a structural feature defines the surface shape at the surface facing the plasma, which assists in crushing the standing wave and / or prevents standing waves from being formed in the plasma space. For example, this structural feature may include a collection of concentric rings having a substantially rectangular cross section and protruding from the surface of the upper electrode or defined within the surface of the electrode. The cross-sectional size, shape, dimensions, and spacing of the rings are all chosen such that the system produces a plasma of uniform density. The top electrode may comprise the structural feature and / or the dielectric member or sheet covering the top electrode, which prevents or inhibits corrosion of the structural features while maintaining plasma uniformity. The main power for plasma generation can be supplied to the upper electrode or the lower electrode, and the bias power can be selectively supplied to the lower electrode. This technique can provide a uniform plasma even when using VHF power and / or using an electrode having a relatively large surface area.

One embodiment includes an electrode plate configured for use in a parallel plate capacitively coupled plasma processing apparatus. The plasma processing apparatus includes a processing chamber for forming a processing space of a sufficient size to accommodate a target substrate. A process gas supply unit configured to supply process gas to the process chamber is provided. The exhaust unit connected to the exhaust port of the treatment chamber evacuates the gas from the inside of the treatment chamber. The first electrode and the second electrode are arranged to face each other in the process chamber. The first electrode is an upper electrode and the second electrode is a lower electrode. The second electrode is configured to support the target substrate through the mount table. The first RF power applying unit is configured to apply a first RF power to the first electrode and the second RF power applying unit is configured to apply a second RF power to the second electrode. Alternatively, the first RF power applying unit may be configured to apply the first RF power to the second electrode. The electrode plate may be mounted on the first electrode. The electrode plate has a surface area facing the second electrode when mounted on the first electrode. The surface area includes a collection of concentric rings that are substantially flat and protrude from the surface area. Each concentric ring has a predetermined cross sectional shape, and each concentric ring is spaced from a neighboring concentric ring by a predetermined gap distance. A dielectric member or sheet may also be provided. The dielectric member is disposed in the set of concentric rings on the electrode plate. The dielectric member has a sufficient size to cover the set of concentric rings and / or the electrode plate. The dielectric member may have a substantially flat surface facing the second electrode. The dielectric member facing the first electrode may also have a substantially flat surface or the dielectric member may fill a gap or space between the concentric rings in the electrode plate.

Another embodiment includes a plasma processing apparatus. It may contain several components. The processing chamber forms a processing space for accommodating the target substrate. The process gas supply unit is configured to supply process gas to the process chamber. The exhaust unit is connected to the exhaust port of the process chamber to evacuate the gas from the inside of the process chamber. The first electrode and the second electrode are arranged to face each other in the process chamber. The first electrode is an upper electrode and the second electrode is a lower electrode. The second electrode is configured to support the target substrate through the mount table. The first electrode includes an electrode plate having a surface facing the second electrode. The surface is substantially flat and has an outer boundary of a predetermined shape. The surface comprises a collection of long protrusions. Each elongate projection extends a predetermined height from the surface. Each elongate projection extends along the flat surface about the center point of the first electrode. At least a portion of the elongate projection has a long elongated shape substantially similar to an outer boundary of the surface. The set of protrusions is disposed on the surface such that a portion of the protrusions is surrounded by at least one other protrusion. Each given elongated projection may be spaced a predetermined distance from the adjacent elongated projection. The first radio frequency (RF) power applying unit may be configured to apply a first RF power to the first electrode or to the second electrode according to the configuration of the special plasma processing apparatus. The plasma processing apparatus may include a dielectric member disposed on the set of elongated protrusions on the electrode plate, the dielectric member having a size sufficient to cover the set of elongated protrusions, And the dielectric member provides a barrier between the set of long protrusions and the plasma generating space.

Another embodiment includes a method of generating a uniform plasma for processing a substrate using a plasma processing apparatus. The plasma processing apparatus includes a vacuum evacuable processing chamber, a lower electrode assembly disposed in the processing chamber and serving as a mounting table for the target substrate, an upper electrode arranged to face the lower electrode in the processing chamber, (RF) power supply. The device and the electrode may be of sufficient size for special applications. For example, for wafer etching or CVD, the electrode may be sized to accommodate a 300 mm or 400 mm diameter wafer. For CVD in solar cells, the electrodes may be of a substantially larger size, e.g., of about 1-2 meters in side dimension, and may be implemented as a single-sided electrode without needing to be subdivided into a group of electrodes have. The first RF power source supplies the first RF power to the upper electrode or the lower electrode. The target substrate is loaded in the processing chamber and mounted on the lower electrode assembly. The initial gas is evacuated from the process chamber. A process gas is supplied to the process chamber. Plasma is generated from the process gas by applying a first RF power to the top electrode (or the bottom electrode according to a special plasma system). The upper electrode has a surface area facing the second electrode. Wherein the surface region comprises a concentric ring, a nested ring, or a collection of fins that are substantially flat and protruding from the surface region, the set of concentric rings being positioned in a predetermined spacing distribution, And the concentric ring of the ring-shaped ring has a predetermined cross-sectional shape. A dielectric member or sheet is disposed on the concentric ring to prevent or prevent corrosion of the concentric ring by the plasma.

Of course, the order of description of the various steps described herein is provided for the sake of clarity. In general, these steps may be performed in any suitable order. Furthermore, while the different features, techniques, configurations and the like of the present invention can be described in different places in this specification, the respective concepts are intended to be implemented independently of each other or in combination with each other. Thus, the present invention may be embodied and illustrated in many different ways.

It is noted that this summary does not specify all embodiments of the present specification or claimed invention and / or progressively new embodiments. Instead, this summary provides only a preliminary description of the different embodiments of the prior art and corresponding novelty items. Further details and / or possible perspectives of the invention and its embodiments will be referred to the detailed description of the specification and the corresponding figures, which will be described later.

A more complete understanding of the various embodiments of the present invention and many of the attendant advantages of the invention will become more apparent by reference to the following detailed description when taken in conjunction with the accompanying drawings. The accompanying drawings are not necessarily to scale, emphasis instead being placed upon illustrating the features, principles and concepts.
1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to the embodiment described herein.
2 is a side cross-sectional view of an upper electrode according to an embodiment described herein.
3 is a bottom view of the upper electrode according to the embodiment described here.
4 is an enlarged side cross-sectional view of the upper electrode according to the embodiment described herein.
5 is a perspective cross-sectional view of an upper electrode according to an embodiment described herein.
6A-6D are side cross-sectional views of exemplary upper electrode projections according to embodiments described herein.
7A and 7B are exemplary lateral cross-sectional views of the top electrode shape according to the embodiments described herein.
8A and 8B are bottom views of an upper electrode showing various protrusion patterns.
Figures 9A and 9B are diagrams of electron density without using the embodiments herein.
Figs. 10A and 10C are contour diagrams of the electron density without using the embodiment here.
10B and 10D are contour diagrams of electron density results according to the embodiments herein.
11 is a side cross-sectional view of the upper electrode according to the embodiment described herein.
12 is a bottom view of the upper electrode according to the embodiment described here.
13 is a side cross-sectional view of an upper electrode plate and a dielectric member according to an embodiment herein.
14 is an enlarged side cross-sectional view of the upper electrode plate and dielectric member according to the embodiment described herein.
15 is a side cross-sectional view of an upper electrode plate and a dielectric member according to an embodiment herein.
16 is an enlarged side cross-sectional view of the upper electrode plate and dielectric member according to the embodiment described herein.

In the following description, specific details are set forth, such as the specific geometry of the processing system and the description of the various components and processes used in the processing system. It should be understood, however, that the invention may be embodied in other specific forms that depart from these specific details, and that such details are illustrative and not restrictive. The embodiments described herein will be described with reference to the accompanying drawings. Similarly, for purposes of explanation, specific numbers, materials, and configurations are disclosed to provide a thorough understanding. However, embodiments may be practiced without such specific details. Components having substantially the same functional configuration are denoted by the same reference character, so that any redundant description can be omitted.

Various techniques will be described as a plurality of separate operations in order to facilitate understanding of various embodiments. The order of description should not be construed to imply that these operations are necessarily order dependent. In fact, these operations need not be performed in the order presented. The operations described herein may be performed in an order different from the described embodiment. Various additional operations may be performed, and / or the operations described herein may be omitted in further embodiments.

As used herein, the term "substrate" or "target substrate" generally refers to an object to be treated in accordance with the present invention. The substrate may comprise any material or portion of a device, particularly a semiconductor or other electronic device, and may be a base substrate structure, such as, for example, a semiconductor wafer, or a layer on a base substrate structure, such as a thin film. Thus, the substrate is not limited to any particular underlying structure, a lower or upper layer, a patterned or unpatterned, but rather any such layer or base structure, and any combination of layers and / or base structures And the like. The following discussion refers to a particular type of substrate, but this is merely for illustrative purposes.

The technique described herein includes a plasma processing system configured to enable uniform plasma generation and the associated electrode plate. The electrode plate has a surface facing the plasma generating space, and the plasma facing surface includes a structure that promotes plasma uniformity even when plasma is generated using very high frequency (VHF) RF (radio frequency) power do. Such a surface structure may include raised concentric rings / pins, nested loops or other projections that provide a radial barrier. Each ring from the set of concentric rings may have a cross-sectional height, cross-sectional width and cross-sectional shape designed to promote macroscopic and microscopic plasma uniformity, as well as spacing from neighboring rings. The dielectric member or sheet may have a size and location that entails an electrode plate and protects structures on the plasma facing surface. For example, such a dielectric member can be mounted on an electrode plate.

There are a plurality of different plasma processing apparatuses that use different approaches to generate plasma. For example, various approaches may include among other things, inductively coupled plasma (ICP), slot antenna microwave plasma, surface wave plasma and capacitively coupled plasma (CCP). For convenience, the embodiments presented herein are described in the context of a parallel plate capacitively coupled plasma (CCP) system, although other approaches utilizing electrodes may also be used with various embodiments.

1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to an embodiment herein. The plasma processing apparatus 100 of FIG. 1 is a capacitively coupled flare plasma etching apparatus including a top electrode having protrusions or structures of a predetermined pattern projecting from a top electrode to a plasma space. It should be noted that the techniques herein may be used with other plasma processing apparatus, such as for plasma cleaning, plasma polymerization, plasma enhanced chemical vapor deposition (PECVD), and the like.

More specifically, the plasma processing apparatus 100 has a processing chamber 110 that defines a processing vessel that provides, for example, a substantially cylindrical processing space. The processing vessel may be formed of, for example, an aluminum alloy, and may be electrically grounded. The inner wall of the processing vessel may be coated with alumina (Al ₂ O _3), yttria (Y ₂ O ₃₎ or other protective agent. The susceptor 416 forms a part of the lower electrode 400 (lower electrode assembly) as an example of a second electrode serving as a mounting table for mounting the wafer W thereon as a substrate. Specifically, the susceptor 416 is supported on the susceptor support 114, which is provided approximately at the center of the bottom of the processing chamber 110 via the insulating plate 112. The susceptor support 114 may be cylindrical. The susceptor 416 may be formed of, for example, an aluminum alloy.

The susceptor 416 is provided thereon with an electrostatic chuck 418 for holding the wafer W (as part of the lower electrode assembly). The electrostatic chuck 418 is provided with an electrode 410. Electrode 410 is electrically connected to DC (direct current) power supply 122. The electrostatic chuck 418 attracts the wafer W by a coulomb force generated when a DC voltage from the DC power supply 122 is applied to the electrode 410. [

A focus ring 424 is provided on the upper surface of the susceptor 416 so as to surround the electrostatic chuck 418. For example, a cylindrical inner wall member 126 formed of quartz is attached to the outer peripheral side of the electrostatic chuck 418 and the susceptor support 114. The susceptor support 114 includes an annular coolant path 128. The annular coolant path 128 is connected to a chiller unit (not shown) installed outside the processing chamber 110, for example, through the lines 130a and 130b. Coolant (cooling fluid or cooling water) circulating through the lines 130a and 130b is supplied to the annular coolant path 128. Therefore, the temperature of the wafer W mounted on the susceptor 416 can be adjusted.

The gas supply line 132 passing through the susceptor 416 and the susceptor support 114 is configured to supply a thermal conduction gas to the upper surface of the electrostatic chuck 418. A heat conduction gas (backside gas) such as helium (He) may be supplied between the wafer W and the electrostatic chuck 418 through the gas supply line 132 to assist heating of the wafer W have.

The upper electrode 300 (i.e., the upper electrode assembly), which is an example of the first electrode, is vertically provided on the lower electrode 400 so as to be parallel to the lower electrode 400. A plasma generating space or plasma space PS is defined between the lower electrode 400 and the upper electrode 300. The upper electrode 300 may include a disk-shaped inner upper electrode 302 and the outer upper electrode 304 may be an annular shape surrounding the outer side of the inner upper electrode 302. The inner upper electrode 302 also functions as a processing gas inlet for injecting a specific amount of the processing gas toward the plasma generating space PS on the wafer W mounted on the lower electrode 400. [ Thus, the upper electrode 300 forms a showerhead.

More specifically, the inner upper electrode 302 includes a plurality of gas injection openings 324 and an electrode plate 310 (typically circular) with a projection 314. The projection 314 and its construction will be described later in detail. The inner upper electrode 302 also includes an electrode support 320 detachably supporting the upper side of the electrode plate 310. When the electrode plate 310 is circular, the electrode support 320 may be formed into a disk shape having a diameter substantially equal to that of the electrode plate 310. In an alternative embodiment, the electrode plate 310 may be square, rectangular, polygonal, or the like. The electrode support 320 may be formed of, for example, aluminum and may include a buffer chamber 322. The buffer chamber 322 is used to diffuse the gas and has a disc-shaped space. Process gas from the gas supply system 200 is introduced into the buffer chamber 322. The process gas may then be transferred from the buffer chamber 322 to the gas injection holes 324 in its lower surface. Wherein the inner upper electrode essentially provides a sour head electrode.

A ring-shaped dielectric 306 is interposed between the inner upper electrode 302 and the outer upper electrode 304. An insulating shielding member 308 having a ring shape and formed of, for example, alumina is interposed in an airtight manner between the inner peripheral wall of the process chamber 110 and the outer upper electrode 304.

The outer upper electrode 304 is electrically connected to the first high frequency power supply 154 through a power feeder 152, a connector 150, an upper feed rod 148 and a matching unit 146. The first high frequency power supply 154 can output a high frequency voltage having a frequency of 40 MHz or more (for example, 60 MHz) or a high frequency (VHF) voltage having a frequency of 30 to 300 MHz. This power supply may be referred to as the main power supply as compared to the bias power supply. The power feeder 152 may be formed, for example, in a substantially cylindrical shape with its bottom surface opened. The feeder may be connected to the outer upper electrode 304 at its lower end. The power feeder 152 is electrically connected to the lower end of the upper feed rods 148 at the central portion of the upper surface thereof by the connector 150. The upper feed rod 148 is connected to the output side of the matching unit 146 at its upper end. The matching unit 146 is connected to the first high frequency power supply 154 and can match the load impedance with the internal impedance of the first high frequency power supply 154. Note, however, that the outer upper electrode 304 is optional and that the embodiment can function with a single upper electrode.

The feeder 152 is covered on the outside by a grounding conductor 111 whose diameter of the sidewall can be cylindrical, which is approximately the same as the diameter of the process chamber 110. The lower end of the ground conductor 111 is connected to the upper portion of the side wall of the process chamber 110. The upper feed rod 148 passes through the center of the upper surface of the ground conductor 111. An insulating member 156 is interposed in the contact portion between the ground conductor 111 and the upper feed rod 148.

The upper surface of the electrode support 320 is electrically connected to the lower power supply rod 170. The lower feed rod 170 is connected to the upper feed rod 148 through the connector 150. The upper feed rods 148 and the lower feed rods 170 form power feed rods (collectively referred to as "feed rods") that supply high frequency power from the first high frequency power source 154 to the upper electrodes 300 . The lower feed rod 170 is provided with a variable capacitor 172. Frequency power is applied from the first high frequency power supply device 154 by adjusting the capacity of the variable capacitor 172. The power of the external upper electrode 304 The relative ratio of the electric field intensity formed immediately below can be adjusted.

A gas exhaust port 174 is formed at the bottom of the process chamber 110. The gas exhaust port 174 is connected through a gas exhaust line 176 to a gas exhaust unit 178 which may include, for example, a vacuum pump. The gas exhaust unit 178 exhausts the interior of the processing chamber 110 so that the internal pressure of the processing chamber 110 is reduced to a desired degree of vacuum. The susceptor 416 may be electrically connected to the second high frequency power supply 182 through the matching unit 180. The second high frequency power supply 182 can output a high frequency voltage in the range of 2 MHz to 20 MHz, for example, 2 MHz.

The inner upper electrode 302 of the upper electrode 300 is electrically connected to a low pass filter (LPF) 184. The LPF 184 cuts off the high frequency from the first RF power supply 154 and passes the low frequency from the second RF power supply 182 to the ground. On the other hand, the susceptor 416 forming part of the lower electrode is electrically connected to the high pass filter (HPF) 186. The HPF 186 passes high frequencies from the first HF power supply 154 to ground. The gas supply system 200 supplies gas to the upper electrode 300. The gas supply system 200 includes a process gas supply unit 210 for supplying a process gas for performing a specific process such as film formation, etching, and the like on a wafer, for example, as shown in Fig. The process gas supply unit 210 is connected to the process gas supply line 202 forming the process gas supply path. The process gas supply line 202 is connected to the buffer chamber 322 of the inner upper electrode 302.

The plasma processing apparatus 100 is connected to a control unit 500 that controls various components of the plasma processing apparatus 100. For example, the control unit 500 may include a DC power supply 122, a first high frequency (or VHF) power supply unit 154, a second high frequency (or VHF) power supply unit 154, etc. In addition to the process gas supply unit 210 of the gas supply system 200, Or VHF) power supply 182 and the like.

Note that the inner upper electrode 302 includes an electrode plate 310 that faces the lower electrode 400, thereby forming a parallel plate of the capacitively coupled plasma tool. The electrode support 320 contacts the rear surface of the electrode plate 310 facing the lower electrode 400 (here, the rear surface of the electrode plate), and detachably supports the electrode plate 310. In an alternative embodiment, the electrode plate 310 may be integral with the upper electrode 300. However, it is advantageous to allow the electrode plate 310 to be detachable because the plasma chemically reacts to corrode the surface region facing the lower electrode. Thus, the electrode plate can be removed for replacement, or to select electrode plates of various different types of materials suitable for a particular type of plasma treatment.

The upper electrode 300 may also include a cooling plate or cooling mechanism (not shown) for controlling the temperature of the electrode plate 310. The electrode plate 310 may be formed of a conductor or a semiconductor material such as Si, SiC, doped Si, aluminum, or the like.

In operation, the plasma processing apparatus 100 generates a plasma at the PS using an upper electrode and a lower electrode. The resulting plasma is then subjected to various types of processing such as plasma etching, chemical vapor deposition, processing of glass materials, and processing of large panels such as, for example, thin film solar cells, organic / inorganic plates for other photoelectric cells and flat panel displays May be used to process a target substrate, such as a wafer W or any material, to be treated. For convenience, this plasma generation will be described with reference to the etching of the oxide film formed on the wafer W. First, the wafer W is loaded into the processing chamber 110 from a load lock chamber (not shown) after the gate valve (not shown) is opened, and mounted on the electrostatic chuck 418. Then, when a DC voltage is applied from the DC power supply 122, the wafer W is electrostatically attached to the electrostatic chuck 418. Then, the gate valve is closed, and the process chamber 110 is evacuated to a certain vacuum level by the gas exhaust unit 178.

Next, a process gas is introduced into the buffer chamber 322 of the upper electrode 300 from the process gas supply unit 210 through the process gas supply line 202, and the flow rate thereof is controlled by, for example, . The processing gas introduced into the buffer chamber 322 is uniformly discharged from the gas injection hole 324 of the electrode plate 310 (showerhead electrode) to the wafer W, The pressure is maintained at a certain level.

A high frequency power in the range of 3-150 MHz, for example, 60 MHz, is applied from the first high frequency power supply device 154 to the upper electrode 300. As a result, a high frequency electric field is generated between the susceptor 116 forming the lower electrode and the upper electrode 300, and the process gas is dissociated and converted into plasma. A low frequency power in the range of 0.2-20 MHz, for example, 2 MHz, is applied from the second high frequency power supply 182 to the susceptor 116 forming the lower electrode. In other words, a dual frequency system can be used. As a result, ions in the plasma are attracted toward the susceptor 116, and the anisotropy of the etching is increased by the ion assist force. For convenience, FIG. 1 illustrates that the first power supply 154 supplies power to the upper electrode. In an alternative embodiment, the first power supply 154 may supply power to the lower electrode 400. [ Therefore, both the main power (excitation power) and the bias power (ion acceleration power) can be supplied to the lower electrode.

A major challenge associated with capacitively coupled plasma tools is plasma non-uniformity. The predetermined plasma processing may be advantageous when using very high frequency (VHF) power in the range of 30-300 MHz. However, such VHF power tends to generate an uneven electric field. At higher frequencies, the wavelength decreases but the non-uniformity increases. Especially when the wavelength is relatively smaller than the diameter of the electrode. This nonuniformity is problematic because it induces non-uniform exposure of the wafer W and induces defects of the wafer W. [

The generation of a uniform plasma is tricky. In an ideal plasma, the distribution of ions and electrons moving in the plasma is the same. There are different variables in play that can affect plasma uniformity. These variables include power, frequency, pressure, material, and so on. One measure of non-uniformity is the electron density in the plasma at various locations. 9A shows a diagram of the electron density (plasma intensity) in relation to the position of the electrode plate. In this diagram, the X axis represents the distance from the center point of the wafer (aligned with the electrode plate), where 0 is the center of the wafer. The Y axis represents the relative electron density. Note that there is a significant difference in electron density 602 between the center and the edge of the wafer. The electron density at the center of the wafer is three to four times greater than the electron density at the edge, so there is a sharp center peak.

Similarly, FIG. 9b has a similar high center distribution or electron distribution. Figure 9b differs from Figure 9a in that it uses a higher pressure. Because of the higher pressure, there is still a center peak (electron density difference 604) that is about three to four times the electron density at the edge, but at this higher pressure there is also a second peak near the edge of the wafer or electrode Pay attention to the point.

10A is a contour diagram showing the electron density in the plasma space with respect to the upper electrode 309 and the lower electrode 400. FIG. The upper electrode 309 (or electrode plate) has a substantially flat surface like a conventional electrode plate. Figure 10A correlates with Figure 9A. The darker space in this outline shows higher electron density. Thus, FIG. 10A shows a high electron density at the center of the plasma space and a relatively low electron density toward the edge of the electrode. 10C is similar to FIG. 10A except that FIG. 10C correlates with FIG. 9B. Thus, it is noted that not only is there a high center electron density, but there is a (smaller) second order peak at the edge of the plasma space.

Thus, it has been recognized that the techniques described herein facilitate, for example, uniform electron density in the plasma by removing and / or controlling these waves. These techniques include using one or more structures in the electrode plate 310. Such a structure is located on the plasma-facing surface of the electrode plate 310. Such a structure may be configured to provide one or more barriers in a radial direction, i.e., outwardly from a center point of the electrode plate 310.

Referring now to FIG. 2, a side cross-sectional view of an exemplary electrode plate 310 is shown. The surface region 312 has a plurality of protrusions 314. Note that such a structure (protrusion) forms a kind of barrier when moving along the surface region 312 from the center point 318 toward the outer boundary 316.

3 is a bottom view of the electrode plate 310. FIG. In this figure, the projection 314 is shown as a collection of concentric rings centered about the center point 318. In some embodiments, the set of concentric rings may have even, i.e., equidistant, spacing. In another embodiment, the interval may be variable. The cross-sectional size and shape and the gap distance between the concentric rings can be based on the plasma wavelength or the expected plasma wavelength. The number of concentric rings may also vary with the diameter of the surface area 312. The ring or protrusion 314 can be mounted or secured (welded, welded, clamped) to the surface area 312 or integrated with the electrode plate 310 by machining the protrusions or casting the electrode plate .

4 is an enlarged cross-sectional view of the electrode plate 310. Fig. In this figure, protrusion 314 is shown having a generally rectangular cross-sectional shape with round 332 and fillet 334. This rounding is not necessary but can have a beneficial effect when controlling wave propagation. Each projection may have a predetermined cross-sectional width 336 and a predetermined cross-sectional height 338. Adjacent protrusions are separated from each other by the gap interval 340. This gap spacing 340 can be measured from the edge to the edge, from the center to the center, or in other manners. The values of these dimensions may be absolute or relative. For example, the values may be selected from a range of dimensions depending on the electrode plate diameter, depending on the particular etch / deposition process, or depending on the plasma wavelength of the generated plasma. In the case of a VHF plasma with a wavelength of 1-10 cm, the projection dimensions and gap spacing can be determined according to their wavelengths to produce optimal plasma uniformity.

5 is an enlarged cross-sectional perspective view of an electrode plate 310 showing a surface area 312 facing the plasma space. For convenience, the apertures 324 (or holes) of the electrode plate 310 are shown as not penetrating the protrusions 314. In other embodiments, the apertures 324 can penetrate through the protrusions 314, i.e. concentric rings, depending on the width of the special pin.

There are various cross-sectional shapes that may be selected for use in the embodiments herein. For example, Figure 6a shows a relatively thin cross-sectional shape in which protrusion 314 is essentially a pin protruding from surface region 312. [ 6B shows a protrusion 314 having a trapezoidal shape. In Fig. 6C, the protrusion 314 has a round shape, that is, a semicircular shape. In Fig. 6D, the protrusion 314 has a triangular shape.

In addition to the various cross-sectional shapes of the protrusions 314, the electrode plate 310 may have an alternative cross-sectional shape. For example, Figure 7a shows an electrode plate 310 having a Gaussian lens shape in that the surface area 312 has a concave curvature (with respect to the plasma space PS). 7B, the electrode plate has a surface region 312 that is stepped in that the different portions of the surface region 312 have different vertical distances from the lower electrode 400.

8A is a bottom plan view of an alternative embodiment of the electrode plate 310. FIG. 8A shows an electrode plate 310 having a rectangular surface area 312 with rectangular and elliptical long protrusions surrounding the center of the electrode plate, instead of a set of concentric rings. 8B, protrusion 314 is a non-continuous, concentric ring with openings or cracks, but such protrusion 314 still provides a barrier that is substantially perpendicular to the predetermined radial direction in surface area 312. In another embodiment, the ring or projection is continuous.

With these protrusions in the electrode plate of the corresponding plasma processing apparatus, the plasma processing apparatus can provide uniform electron density even at VHF power. FIGS. 10B and 10D show an exemplary contour diagram of electron density in a plasma processing apparatus using an electrode plate 310 having concentric rings or other elongated protrusions. It is noted that the electron density is uniform throughout as a result of such electrode plate projections throughout the plasma space. Without the teachings of the present invention, plasma non-uniformity can be as high as 200% or more, but according to the teachings of the present invention, plasma non-uniformity can be less than 10%.

11 and 12 show another exemplary configuration of the electrode plate 310. [ 11 is a side cross-sectional view of an exemplary electrode plate 310, and Fig. 12 is a bottom view of the electrode plate 310. Fig. Surface 312 has a plurality of protrusions 314 (such as fins) that protrude from the surface or are otherwise attached to the surface. Note that the protrusions 324 are disposed on the outer portion of the surface 312. Thus, the inner circular portion of the surface 312 has no projections, and the outer ring-shaped portion (edge region) of the surface 312 includes a plurality of concentric ring-shaped projections 314. It is also noted that the projections 314 have a generally triangular or conical cross-sectional shape. Instead of the sidewalls of the protrusions 314 being perpendicular to the surface 312, the sidewalls have an obtuse angle with respect to the surface 312. For example, this obtuse angle may be between about 100 degrees to 160 degrees from surface 312 to the adjacent side wall. By providing the side wall at an angle, plasma uniformity can be further promoted. For example, higher frequency electromagnetic waves traveling in the vicinity of the surface region 312 or across the surface region 312 can be deflected into the plasma space, thereby increasing uniformity. In this embodiment, as in the typical case, RF of higher frequency may be supplied from the upper electrode and lower RF frequency may be supplied from the lower electrode. However, this embodiment can also function effectively even when a high frequency is applied from the lower electrode and a low frequency is applied from the upper electrode.

Referring now to FIG. 13, a side cross-sectional view of an exemplary electrode plate 310 similar to that shown in FIG. 2 is shown. Dielectric member 370 is shown adjacent electrode plate 310 or covering electrode plate 310. The dielectric member 370 is shown as a substantially planar sheet with gas injection holes 326 aligned with the gas injection holes 324 from the electrode plate 310. The dielectric member can be made of various dielectric materials. For example, for polysilicon etch applications, the dielectric member may be selected as quartz. In the dielectric etching treatment, the dielectric member may be a low-conductivity single silicon crystal, a ceramic thin film on aluminum, or the like. The dielectric member may also be selected to be consumed in a plasma treatment using a dielectric member including, for example, molybdenum nitride, during a physical vapor deposition (PVD) process.

14 is an enlarged cross-sectional view of the electrode plate 310 and the dielectric member 370. Fig. In this embodiment, the dielectric member 370 lies over the protrusions 314 (or contacts the protrusions 314). Note that in addition to the gas injection holes 326 being aligned with the gas injection holes 324, the gas injection holes may have wider apertures facing the electrode plates. This may be advantageous to compensate for any misalignment of the dielectric member at the electrode plate. As the dielectric member 370 is deflected to the electrode plate 310, the dielectric member protects the protrusions or pins of the electrode plate from being corroded and damaged by the generated plasma. Thus, the generated plasma can directly contact the dielectric member on the substrate and the upper electrode on the lower electrode to protect both electrodes.

Referring now to Fig. 15, a side cross-sectional view of an exemplary electrode plate 310 similar to that shown in Fig. 2 is shown. In Fig. 15, the dielectric member 370 is shown adjacent to the electrode plate 310 and not only covers the electrode plate 310, but also fills the gap between the protrusions 314.

16 is an enlarged cross-sectional view of the electrode plate 310 and the dielectric member 370 shown in Fig. In this embodiment, the dielectric member 370 fills the gap between the protrusions (or rings) as well as lies over the protrusions 314 (or contacts the protrusions 314). The gas injection hole may optionally have wider apertures facing the electrode plate, which may be advantageous to compensate for any misalignment of the dielectric member in the electrode plate, especially when the diameter of the gas injection hole is relatively small.

It is clear that there are various alternative embodiments provided by the techniques of the present invention.

One embodiment includes an electrode assembly for use in a plasma processing apparatus. The electrode assembly may be a removable electrode or a more permanent electrode. The electrode assembly includes an electrode plate configured for use in a parallel plate capacitively coupled plasma processing apparatus. The plasma processing apparatus includes a processing chamber for forming a processing space. The processing space is of sufficient size to accommodate a target substrate, such as a semiconductor wafer or flat plate. The process gas supply unit is configured to supply the process gas to the process chamber. An exhaust unit is connected to an exhaust port of the treatment chamber for evacuating gas from the inside of the treatment chamber. The first electrode and the second electrode are arranged to face each other in the treatment chamber. The first electrode may be the upper electrode 300 and the second electrode may be the lower electrode 400. The second electrode is configured to support the target substrate through the mount table. A first radio frequency (RF) power application unit is configured to apply a first RF power to the first electrode. Alternatively, the first RF power applying unit may be configured to apply a first RF power to the second electrode. The first RF power applying unit may include a power supply unit or a circuit for receiving and applying an external power supply unit. And the second RF power applying unit is configured to apply the second RF power to the second electrode. The electrode plate can be mounted on the first electrode. The electrode plate has a surface area facing the second electrode when mounted on the first electrode. The surface area of the electrode plate is substantially flat and comprises a collection of concentric rings. A concentric ring protrudes from the surface area or is defined in the electrode plate. Each concentric ring has a predetermined cross-sectional shape, and each concentric ring is spaced from a neighboring concentric ring by a predetermined gap distance, such as a specific radial spacing.

The power configuration may vary depending on the type of plasma processing. For example, in the case of an etching application, the main power (first RF power) may be supplied to the upper electrode or the lower electrode. It may be advantageous to supply the main power to the upper electrode in the case of special etching process parameters (wafer type, process gas, etc.), but it may be advantageous to supply the main power to the lower electrode. However, in the case of PECVD, it is typically more advantageous to supply the main power to the top electrode.

The electrode assembly may include a dielectric member disposed on (or in contact with) a concentric ring assembly of the electrode plate. The dielectric member can be of sufficient size to cover the concentric ring assembly. That is, the dielectric member can extend to the outer boundary (or beyond the outer boundary) of the concentric ring assembly or electrode plate. The dielectric member may have a substantially flat surface facing the second electrode. The dielectric member can extend or sustain the gas injection hole of the electrode plate.

In some embodiments, the dielectric member may have a substantially flat surface facing the concentric ring assembly. In another embodiment, the dielectric member is disposed in a concentric ring set of electrode plates. The dielectric member may be sized and positioned such that the dielectric member provides a barrier between the concentric ring assembly and the plasma generating space. This barrier can then protect the concentric ring assembly from damage caused by the plasma generated in the plasma generating space. In an alternative embodiment, the concentric ring electrode assembly includes a conformal protective coating that inhibits damage from the plasma in contact with the electrode plate. Such a protective coating may be, for example, yttria or alumina.

Sectional height of each concentric ring is greater than about 1.0 millimeter and less than about 20.0 millimeters and the predetermined gap spacing is greater than about 1.0 millimeter and less than about 50 millimeter Lt; / RTI >

The cross-sectional height of each concentric ring may be greater than about 0.5 millimeters and less than about 10.0 millimeters. In addition, the cross-sectional width of each concentric ring may be greater than about 1.0 millimeter and less than about 20.0 millimeters. The predetermined gap spacing may be greater than about 1.0 millimeter and less than about 50.0 millimeters. Other embodiments have a narrower range. For example, the cross sectional height of each concentric ring is greater than about 1.0 millimeter and less than about 3.0 millimeters, the cross-sectional width of each concentric ring is greater than about 2.0 millimeters and less than about 5.0 millimeters, and the predetermined gap spacing is greater than about 6.0 millimeters And is less than about 20.0 millimeters.

The first RF power applied may be 3-300 MHz, or in the case of a VHF application, 30-300 MHz. For example, the RF power may be about 40-100 MHz. The applied second RF power may be about 0.5-13 MHz. The technique of the present invention may be effective when the frequency is lower than the RF frequency. The cross-sectional height of each concentric ring, the cross-sectional width of each concentric ring, and the predetermined gap spacing may all be selected based on the diameter of the surface region of the electrode plate. For example, a 300 mm diameter wafer may have a different configuration than a 450 mm diameter wafer. The sectional shape of each concentric ring may be substantially rectangular. This roughly rectangular cross-sectional shape may have a round with a radius of 0.2-1.0 mm, and a fillet with a radius of about 0.2-1.0 mm.

In another embodiment, the plasma processing apparatus includes a processing chamber for forming a processing space of a sufficient size for accommodating a target substrate, a processing gas supply unit configured to supply processing gas to the processing chamber, An exhaust unit connected to the exhaust port of the process chamber to perform the first RF power application, and a first electrode and a first RF power application unit. The first electrode and the second electrode are arranged to face each other in the process chamber. The first electrode is an upper (hot) electrode and the second electrode is a lower electrode. Alternatively, the upper electrode is not a hot electrode, and instead both the main power and the bias power may be supplied to the lower electrode. The second electrode is configured to support a target substrate. This support may be a direct support, or it may be an indirect support, such as through a mounting table, which may be an electrostatic chuck. In other words, the second electrode (lower electrode assembly) may comprise a mounting table, a surface or other support support, and below which the second electrode is disposed. The first electrode includes an electrode plate having a surface facing the second electrode, the surface being substantially flat and having an outer boundary of a predetermined shape. This surface includes a set of long protrusions. Each elongated protrusion extends or protrudes from the surface by a predetermined height, and each elongated protrusion extends around the center point of the first electrode along a flat surface. At least a portion of the elongate projection has a long shape substantially similar to an outer boundary of the surface. Thus, in the case of a circular electrode, the long protrusion is substantially circular, at least some of the protrusions in the case of an elliptical electrode being elliptical, and in the case of a rectangular electrode, at least some of the protrusions are rectangular. This portion may be all or less than all of the long set of protrusions. The set of long protrusions is disposed on the surface such that a portion of the protrusions is surrounded by at least one other protrusion. In other words, all or some of the long protrusions are nested (if rectangular) or concentric (if rounded). Each given elongated projection may be spaced a predetermined distance from the adjacent elongated projection. Thus, there can be the same or variable space between each of the long protrusions. A first radio frequency (RF) power applying unit is configured to apply a first RF power to the second electrode. The second RF power applying unit may also be configured to apply a second RF power to the second electrode. In an alternative embodiment, a first RF power may be applied to the first electrode.

The plasma processing apparatus may include a dielectric member disposed on the set of the long protrusions on the electrode plate. The dielectric member may have a sufficient size to cover the set of long protrusions. The dielectric member may have a substantially flat surface facing the second electrode. Thus, the dielectric member provides a barrier between the set of long protrusions and the plasma generating space. The dielectric member may have a substantially flat surface facing the set of long protrusions. Optionally, the dielectric member conformally extends into the gap between the elongated protrusions to fill the gaps between the elongated protrusions. In another embodiment, the set of elongate protrusions includes a conformal protective coating that inhibits damage from the plasma in contact with the electrode plate. The protective coating may be used in place of the dielectric member as a means of protecting the electrode plate from corrosion.

Wherein the predetermined height of each projection is greater than about 0.5 millimeters and less than about 10.0 millimeters, the cross-sectional width of each projection is greater than about 1.0 millimeter and less than about 20 millimeters, the gap spacing between adjacent protrusions is greater than about 1.0 millimeter, Lt; / RTI > Alternatively, the predetermined height of each projection is greater than about 1.0 millimeter and less than about 3.0 millimeters, the cross-sectional width is greater than about 2.0 millimeters and less than about 5.0 millimeters, the gap distance between adjacent protrusions is greater than about 6.0 millimeters, Less than millimeter.

The plasma treatment may be performed by a first RF power between 3 and 300 MHz, or a first RF power between 30 and 300 MHz. The predetermined height of each projection and the cross-sectional width of each projection may be selected based on the frequency range of the first RF power such that the plasma generated through the plasma processing apparatus has a substantially uniform electron density across the first electrode have. The height may also be determined based on the wavelength of the plasma wave from the plasma generated in the processing space. At least a portion of the set of long protrusions may have a substantially elongated, elongated shape.

The electrode plate may comprise a material selected from the group consisting of aluminum, silicon and doped silicon. Other materials include stainless steel, carbon, chromium, tungsten, or other semiconducting or conductive materials. The electrode plate may comprise a protective coating.

Another embodiment may include a plasma processing method using an electrode with a projection. For example, in the plasma processing apparatus described above, the processing can be started by loading the target substrate into the processing chamber and mounting the target substrate on the lower electrode. The initial gas from the process chamber is emptied. Thus, all gases present when the target substrate is loaded can be removed. Then, a process gas is supplied to the process chamber. The plasma is generated from the process gas (e.g., argon) by applying a first RF power to the upper or lower electrode. The upper electrode has a surface area facing the second electrode. The surface area is substantially flat and comprises a collection of concentric rings projecting from the surface area. The set of concentric rings is positioned in a predetermined spatial distribution, and each concentric ring has a predetermined cross sectional shape. The upper electrode may comprise a dielectric member disposed over the set of concentric rings. The dielectric member may be a sheet mounted on the upper electrode, which may be substantially planar, and / or may fill a space between the concentric rings. A second RF power supply connected to the lower electrode may be used and the second RF power supply applies a second RF power to the lower electrode to bias the lower electrode. By adjusting the operating frequency in the process chamber as well as the first frequency, the generated plasma can have a specific electron density non-uniformity of less than about 10% over the entire second electrode.

In an alternative embodiment, the number of rings included in the electrode may be based on the diameter of the electrode. Likewise, the cross-sectional dimensions of the projections can be based on the electrode diameter. In some embodiments, the electrode plate used to process 300 mm diameter wafers includes about 2-30 rings, and the electrode plate used to process a 450 mm diameter wafer includes about 3-45 rings . In some embodiments, the gap distance (the spatial distance between adjacent rows or rings of protrusions) is less than the frequency of the plasma wavelength or plasma wavelength generated in the process chamber. In other embodiments, the dimensions may be based on a quarter wavelength.

In some embodiments, the cross-sectional dimension and / or pin space may be based on the frequency applied to the top electrode. For example, if a plasma is generated using a frequency of 3-30 MHz applied to the top electrode, the pin space may have a first predetermined pin space. Next, when a plasma is generated using a frequency of 30-300 MHz applied to the upper electrode, a second predetermined pin space is used, wherein the second predetermined pin space is the first predetermined pin space Lt; / RTI > By applying a higher frequency to the upper electrode, the plasma wavelength can be made much smaller than the electrode plate. For example, if a frequency of 3-30 MHz is applied, the generated plasma may have a wavelength of 15 cm or more, whereas when a frequency of 30-300 MHz (or more) is applied, it may have a wavelength of less than 15 cm , Or less than 1-3 cm due to the effect of higher harmonics. Thus, the dimensions of the upper electrode plate can be based on an adjusted applied power with a specific frequency.

It is advantageous to select the optimum cross-sectional height of the projection. If the height of the protrusion is relatively small, it can still have a high electron density at the center. On the other hand, if the protrusion is too high, the electron density will be kept high at the edge. A typical space between the upper electrode and the lower electrode (space between the surface of the electrode plate and the surface of the target substrate) may be between about 10-100 mm. A typical power range for the top electrode is 50-20,000 watts and the pressure can range from 1 millitorr (mTorr) to 10 Torr.

Although only some embodiments of the present invention have been described in detail above, those skilled in the art will recognize that many modifications are possible in the above-described embodiments without departing substantially from the novel teachings and advantages of the present invention It will be easy to recognize. Accordingly, all such modifications are intended to be included within the scope of the present invention.

Claims (20)

An electrode assembly for use in a plasma processing apparatus,
An electrode plate configured for use in a parallel plate capacitively coupled plasma processing apparatus
/ RTI >
The plasma processing apparatus includes:
A processing chamber forming a processing space sufficient to accommodate a target substrate;
A processing gas supply unit configured to supply a processing gas to the processing chamber;
An exhaust unit connected to an exhaust port of the process chamber for evacuating gas from the inside of the process chamber;
A first electrode and a second electrode disposed opposite to each other in the process chamber, the first electrode being an upper electrode, the second electrode being a lower electrode, and the second electrode being configured to support the target substrate; And
A first radio frequency (RF) power application unit configured to apply a first radio frequency (RF) power to the second electrode,
/ RTI >
Wherein the electrode plate is mountable to the first electrode, the electrode plate has a surface area facing the second electrode when mounted on the first electrode, the surface area is substantially flat and the set of concentric rings Wherein each concentric ring has a predetermined cross sectional shape and each concentric ring is spaced from a neighboring concentric ring by a predetermined gap distance. 2. The antenna of claim 1, further comprising a dielectric member disposed on the set of concentric rings on the electrode plate, the dielectric member having a size sufficient to cover the set of concentric rings, And a substantially planar surface facing the electrode. 3. The electrode assembly of claim 2, wherein the dielectric member has a generally flat surface facing a collection of concentric rings. 2. The plasma processing system of claim 1, further comprising a dielectric member disposed in the set of concentric rings on the electrode plate, wherein the dielectric member is sized and shaped such that the dielectric member provides a barrier between the set of concentric rings and the plasma- Position of the electrode assembly. 5. The electrode assembly of claim 4, wherein the dielectric member conformally extends into a gap between the concentric rings and fills a gap between the concentric rings. 5. The electrode assembly of claim 4, wherein the plasma processing apparatus includes a second RF power applying unit configured to apply a second RF power to the second electrode. 5. The electrode assembly of claim 4, wherein the set of concentric rings protrude from or define below the surface region. 5. The electrode assembly of claim 4, wherein the set of concentric rings includes a conformal protective coating that inhibits damage from plasma contacting the electrode plate. 5. The method of claim 4, wherein the cross sectional height of each concentric ring is greater than about 0.5 millimeters and less than about 10.0 millimeters, the cross-sectional width of each concentric ring is greater than about 1.0 millimeter and less than about 20.0 millimeters, Is greater than about 1.0 millimeter and less than about 50.0 millimeters. 5. The electrode assembly of claim 4, wherein the first RF power is between about 3 MHz and 300 MHz, and the second RF power is between about 0.5 MHz and 13 MHz. In the plasma processing apparatus,
A processing chamber forming a processing space sufficient to accommodate a target substrate;
A processing gas supply unit configured to supply a processing gas to the processing chamber;
An exhaust unit connected to an exhaust port of the treatment chamber for evacuating gas from the inside of the treatment chamber;
A first electrode and a second electrode disposed opposite to each other in the process chamber; And
A first RF power applying unit configured to apply a first radio frequency (RF) power to the second electrode,
/ RTI >
Wherein the first electrode is an upper electrode and the second electrode is a lower electrode, the second electrode is configured to support the target substrate, and the first electrode includes an electrode plate having a surface facing the second electrode Wherein the surface has a substantially flat outer surface with a predetermined shape and the surface comprises a set of elongated protrusions, each elongated protrusion extending from the surface a predetermined height, Wherein at least some of the elongated protrusions have a long shape substantially similar to an outer boundary of the surface, the set of protrusions being such that a portion of the protrusions is at least one other Each of the long protrusions being provided with a predetermined distance from the adjacent long protrusion In that the spacing is arranged, the plasma processing apparatus. 12. The apparatus of claim 11, further comprising a dielectric member disposed on the set of elongate protrusions on the electrode plate, the dielectric member having a size sufficient to cover a collection of the elongated protrusions, Wherein the dielectric member has a substantially flat surface facing the electrode, the dielectric member providing a barrier between the set of elongated protrusions and the plasma generating space. 13. The plasma processing apparatus of claim 12, wherein the dielectric member has a substantially flat surface facing the set of elongated protrusions. 13. The plasma processing apparatus of claim 12, wherein the dielectric member conformally extends into a gap between the elongated protrusions and fills a gap between the elongated protrusions. 13. The plasma processing apparatus of claim 12, wherein the plasma processing apparatus further comprises a second RF power applying unit configured to apply a second RF power to the second electrode. 13. The plasma processing apparatus of claim 12, wherein the set of elongate protrusions comprises a conformal protective coating that inhibits damage from plasma contacting the electrode plate. 13. The plasma processing apparatus according to claim 12, wherein the predetermined height of each projection and the sectional width of each projection are set so that plasma generated through the plasma processing apparatus has a substantially uniform electron density over the entire first electrode, And is selected based on the frequency range of power. An electrode assembly for use in a plasma processing apparatus,
An electrode plate configured to be used in a parallel plate capacitively coupled plasma processing apparatus;
A dielectric member disposed in the set of concentric rings on the electrode plate and having a size sufficient to cover the set of concentric rings,
Lt; / RTI >
The plasma processing apparatus includes:
A processing chamber forming a processing space sufficient to accommodate a target substrate;
A processing gas supply unit configured to supply a processing gas to the processing chamber;
An exhaust unit connected to an exhaust port of the process chamber for evacuating gas from the inside of the process chamber;
A first electrode and a second electrode arranged opposite to each other in the process chamber, the first electrode is an upper electrode, the second electrode is a lower electrode, and the second electrode is configured to support the target substrate through a mount table -;
A first radio frequency (RF) power application unit configured to apply a first radio frequency (RF) power to the first electrode; And
A second RF power applying unit configured to apply a second RF power to the second electrode,
/ RTI >
Wherein the electrode plate is mountable to the first electrode, the electrode plate has a surface area facing the second electrode when mounted on the first electrode, the surface area is substantially flat and the set of concentric rings Wherein each concentric ring has a predetermined cross sectional shape and each concentric ring is spaced from a neighboring concentric ring by a predetermined gap distance. 19. The electrode assembly of claim 18, wherein the dielectric member has a substantially flat surface facing the set of concentric rings and a substantially flat surface facing the second electrode. 19. The electrode assembly of claim 18, wherein the dielectric member conformally extends into a gap between the concentric rings and fills a gap between the concentric rings.

Images