TW201508809A - Plasma processing device and plasma processing method - Google Patents

Abstract

Provided is a plasma processing device that can generate uniform plasma for a large-scale substrate. The plasma processing device comprises the following: a plurality of dielectrics (10) that are disposed on a shared plane and that have a lower surface; a plurality of wave guides (WG) that propagate microwaves to each of the plurality of dielectrics through openings; and a plurality of microwave supply units (70) that supply microwaves to the plurality of waveguides respectively and that are electrically independent from each other. Each of the plurality of dielectrics is provided with a plurality of gas emission holes (11) for emitting gas from the lower surface of the dielectric. The plurality of dielectrics are formed of first dielectric columns comprising dielectrics arrayed in a first direction (x) and second dielectric columns that comprise the dielectrics arrayed in the first direction and that are disposed adjacent to the first dielectric column in a second direction (y). Dielectrics (10) that form either the first or second dielectric column are disposed so as to be deviated, in the first direction, with respect to dielectrics (10) which form the other of the first or second dielectric column.

Description

Plasma processing device and plasma processing method

The present invention relates to a plasma processing apparatus and a plasma processing method for applying a plasma treatment to a substrate.

For example, in a manufacturing process such as an LCD device, a device that uses a microwave to generate plasma in a processing chamber and applies a CVD process, an etching process, or the like to the LCD substrate is used. As such a plasma processing apparatus, it is known that a plurality of waveguides are arranged side by side in parallel with the processing chamber (for example, refer to Patent Documents 1 and 2). Below the waveguide, there are a plurality of slots in parallel with each other, and a flat dielectric is provided along the underside of the waveguide. Thereafter, the microwave is propagated through the groove to the surface of the dielectric, and the specific gas (the rare gas for plasma excitation and/or the gas for plasma treatment) supplied to the processing chamber is made by microwave. The energy (electromagnetic field) is composed of the slurry. For example, in a manufacturing process such as an LCD device, a device that uses a microwave to generate plasma in a processing chamber and applies a CVD process, an etching process, or the like to the LCD substrate is used.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-200646

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-152876

With the increase in the size of the substrate and the like, the processing apparatus is also large, and in particular, the manufacturing of a large-sized dielectric material is difficult, and the manufacturing cost is increasing. Further, if the dielectric material becomes large and becomes heavy, the supporting member to be supported must also be a strong structure, and as a result, the plasma generated in the processing chamber tends to be uneven. In other words, the large-sized support member becomes an obstacle, and it hinders the formation of a uniform electromagnetic field at the entire upper portion of the substrate, and since the dielectric itself is also large in area, it depends on the processing gas. Various conditions such as the type or the pressure in the processing chamber may make it difficult to uniformly propagate the microwave to the entire surface of the dielectric.

It is an object of the present invention to provide a plasma processing apparatus and a plasma processing method capable of generating a uniform plasma for a substrate that has been enlarged.

A plasma processing apparatus according to the present invention is characterized in that: a dielectric material disposed on a common plane and having a plurality of dielectric layers; and a microwave that propagates through the opening portion to the plurality of dielectric materials The guide wave path of the plural of each place; and for the above-mentioned complex guide wave path a microwave supply unit that supplies a plurality of mutually independent microwaves, wherein each of the plurality of dielectric materials has a plurality of gas discharge holes for discharging a gas to be pulverized from the lower surface, the plurality of The dielectric material is formed by the first dielectric matrix formed of the dielectric disposed in the first direction and the dielectric disposed in the first direction, and is formed a second dielectric column arranged adjacent to the first dielectric column in the second direction orthogonal to the first direction, forming one of the first and second dielectric columns The dielectric material is disposed in a biased manner in the first direction with respect to the dielectric material forming the other one.

A plasma processing method according to the present invention is characterized in that, in a container in which a plasma generating mechanism is provided, a process is performed in which a target object is opposed to a lower surface of the first and second dielectric columns. a step of setting the method; and a step of transmitting microwaves of the same phase and the same intensity for the plurality of dielectrics through the plurality of waveguides from the plurality of microwave supply units; and the plasma generating mechanism by the foregoing a step of plasma-reducing gas discharged from a plurality of gas discharge holes, the plasma generation mechanism having: a dielectric layer disposed on a common plane and having the following plural plurality of dielectric materials; a plurality of waveguides for transmitting the microwaves to the respective plurality of dielectrics through the openings; and the plurality of microwave supply units that are electrically independent of each other for the plurality of waveguides, the plural Each of the dielectric materials has a plurality of gas discharge holes for discharging the gas to be pulverized from the lower surface, the plurality of dielectric materials, Arranging is formed in the first side The first dielectric matrix formed by the dielectric material and the dielectric material arranged in the first direction and in a second direction orthogonal to the first direction And the second dielectric column arranged adjacent to the first dielectric column forms one of the first and second dielectric columns, and forms the other dielectric layer The dielectric material is disposed in a biased manner in the first direction.

According to the present invention, the dielectric constituting one of the adjacent first and second dielectric columns and the dielectric constituting the other dielectric are biased in the first direction. The formation of standing waves caused by the propagation of surface waves within the electric quality is suppressed, and as a result, plasma uniformity can be achieved between a plurality of dielectric materials. Further, when a plurality of openings are provided in the waveguide, the phase or intensity of the standing wave at the position of each of the openings is increased by the intensity of the microwaves that are propagated through the openings. The dielectric is changed, but the microwaves are supplied independently of each other for the plurality of guided waves by propagating microwaves of the same phase and the same intensity for a plurality of dielectrics. The homogenization of plasma across a plurality of dielectrics is possible.

1‧‧‧Plastic processing unit

10‧‧‧Spray plate (dielectric)

11‧‧‧ gas release hole

20‧‧‧Connected dielectric

30‧‧‧Fixed components

50‧‧‧guide tube

60‧‧‧ coaxial tube

70‧‧‧Microwave supply unit

211‧‧‧ slot

G‧‧‧ gas

Fig. 1 is a cross-sectional view showing a plasma processing apparatus according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view taken along line II-II of the plasma processing apparatus of Fig. 1.

Fig. 3 is a top view of the plasma processing apparatus of Fig. 1 as viewed from the III-III direction.

[Fig. 4A] The lower view of the shower plate.

4B] A cross-sectional view taken along line IVB-IVB of FIG. 4A.

4C] A cross-sectional view taken along line IVC-IVCB of FIG. 4B.

[Fig. 5] A graph showing the relationship between the diameter of the gas hole, the density of the gas hole, and the pressure of the gas flow path.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present specification and the drawings, constituent elements that have substantially the same functional configurations are denoted by the same reference numerals, and the description thereof will not be repeated.

The plasma processing apparatus (hereinafter referred to as the apparatus 1) of the present embodiment is generally used in various plasma treatments such as plasma CVD (Chemical Vapor Deposition), as shown in Fig. 1 . The apparatus 1 includes a metal processing chamber 200 that partitions the sealed space 201, and a platform 220 that is disposed in the processing chamber 200 and is formed of aluminum nitride or the like for mounting a substrate such as a silicon wafer. And a shower plate 10 made of a dielectric for forming a plasma above the platform 220, and a plurality of connection dielectrics 20 provided on each of the shower plates 10, and a plurality of waveguides 50 on the cover 202 above the processing chamber 200, and microwaves for supplying a plurality of microwaves to the plurality of waveguides 50, respectively Unit 70.

The processing chamber 200 is formed of a conductive material such as aluminum alloy or stainless steel and is connected to a reference potential. At the bottom of the processing chamber 200, an exhaust port 205 for exhausting the atmosphere in the processing chamber 200 is provided, and an exhaust port 205 is connected to an unillustrated portion disposed outside the processing chamber 200. Exhaust device such as vacuum pump. With this exhaust device, the sealed space 201 is decompressed.

The shower plate 10 is formed of a dielectric material such as alumina or quartz. Each of the shower plates 10 is provided with a rectangular outer shape having the same size, and as shown in FIG. 2, a conductive material made of aluminum alloy or the like is provided in a ladder shape at the lower surface of the upper cover 210. The fixing member 30 is formed and fixed under the upper cover 210. In addition, the structure and arrangement of the shower plate 10 will be described later.

The upper cover 210 is formed into a flat plate shape by a conductive material such as aluminum alloy or stainless steel, and is formed with a gas flow path 215 that is connected to the shower plate 10 from the upper surface thereof through the inside. In the gas flow path 215, a gas G to be supplied to the gas supply device (for example, SiH ₄ , N ₂ , O ₂ , N ₂ O, etc.) from a gas supply device (not shown) is connected. In the gas supply device shown, the supply amount and pressure of the gas are adjusted. At the periphery of the connection portion between the gas flow path 215 of the upper cover 210 and the shower plate 10, an O-ring 250 is provided so as not to leak gas. Further, the upper cover 210 and the upper end of the processing chamber 200 are sealed by an O-ring 252.

At the upper cover 210, a plurality of sections are formed A groove 211 of an opening portion of a portion of the waveguide WG that propagates the microwave toward the shower plate 10 is formed. Between the lower surface of the upper cover 210 and the upper surface of the shower plate 10, an O-ring 251 is provided around the groove 211, and the groove 211 is sealed.

The waveguide 50 is formed of a conductive material such as aluminum alloy or copper, and has a rectangular cross section, an open end portion, and an upper end portion that is closed. The waveguide 50 is fixed to the upper cover 201 and extends in a direction perpendicular to the upper surface of the upper cover 210.

The dielectric material for connection 20 is formed of a dielectric material such as fluorinated carbon resin such as alumina, quartz or TEFLON (registered trademark), and is filled in the groove 211 to fill the groove 211. Way to form. The lower end surface of the dielectric material 20 for connection is abutted on the upper surface of the shower plate 10. The upper portion of the dielectric material for connection 20 is formed to have a tapered shape at the front end and extends in the waveguide WG drawn in the region of the waveguide 50. Here, the microwave propagates to the shower plate 10 through the groove 211. However, if the groove 211 is hollow, there is a possibility that the microwave generates reflection and is not efficiently transmitted to the shower plate 10. Sex. Therefore, in the present embodiment, by providing the dielectric material 20 for connection in the groove 211, it is possible to suppress the reflection of the microwave and efficiently propagate the microwave to the shower plate 10.

As shown in FIG. 1 and FIG. 2, one end portion of the coaxial tube 60 is connected to one of the side faces of the waveguide 50 in the longitudinal direction, and the other end portion of the coaxial tube 60 is It is connected to the microwave supply unit 70. The front end of the inner conductor 62 of the coaxial tube 60 The part is highlighted in the waveguide 50. The plurality of microwave supply units 70 are provided with microwave power supplies and an integrator (not shown), and are provided separately from the plurality of waveguides 50, and are electrically independent of each other. Although microwaves having a frequency of about 300 MHz to 6000 MHz can be used, in the present embodiment, each microwave supply unit 70 is configured to supply microwaves of 2450 MHz. As shown in FIG. 2, since the plurality of microwave supply units 70 are disposed on the upper cover 210, it is necessary to miniaturize the microwave supply unit 70 as much as possible. Therefore, in the present embodiment, a solid state type is used at the microwave power source of the microwave supply unit 70. In the solid-state microwave power supply, the high frequency generated by the crystal transmitter is used to increase the frequency and make the microwave signal of the desired frequency by the multiplier circuit, and then use the transistor of several stages. The amplifier circuit is amplified to become a microwave that outputs the desired power. Further, in order to propagate microwaves of the same phase and the same intensity to the plurality of shower plates 10 through the plurality of waveguides WG from the plurality of microwave supply units 70, the plurality of microwave power sources are synchronized with each other. In order to synchronize the plurality of microwave power sources, for example, portions of the crystal transmitter and multiplier circuits can be common to a plurality of microwave power sources. That is, it is only necessary to prepare a set of crystal transmitters and multiplier circuits, and input the outputs to the complex circuits of the plurality. At this time, the cable connecting the divergence and the amplifying circuit is set such that the electrical lengths are equal.

Here, the arrangement and configuration of the shower plate 10 will be described with reference to FIG. 3 and FIGS. 4A to 4C. As shown in FIG. 4A to FIG. 4C, the shower plate 10 is formed by a dielectric material such as alumina. The outer shape is a rectangular plate shape, and includes a flat upper plate portion 12, and a flat lower plate portion 13 disposed to face the same, and a lower plate portion 12 and a lower plate. A gas flow path 14 formed by a closed space between the portions 13. The upper surface 12f of the upper plate portion 12 is formed by a flat surface and is disposed at a lower surface 210f of the upper cover 210 which is formed by a flat surface. Since the upper plate portion 12 is thin and has a low strength, it is generally supported by a cylindrical shape provided between the upper plate portion 12 and the lower plate portion 13 as shown in FIG. 4C or the like. Part 15 was supported. At the upper plate portion 12, as shown in Fig. 4C, a gas introduction hole 16 is formed. The gas introduction hole 16 is connected to the outlet of the gas flow path 215 of the upper cover 210, and supplies the gas G to the inside of the gas flow path 14 through the gas flow path 215. At the lower plate portion 13, as shown in Fig. 4A, a plurality of gas discharge holes 11 are formed at a slightly equal density. Further, in the vicinity of the region where the support portion 15 is present, the gas discharge hole 11 is not formed. In the present embodiment, the size of the gas discharge hole 11 is, for example, 0.5 mm in diameter and 4 mm in depth, and is provided at about 2,200 in one shower plate 100.

The plurality of shower plates 10, which are generally constructed as described above, are provided with the same configuration and the same size, and are fixed to the lower surface 210f of the upper cover 210 by the fixing member 30 as shown in FIG. The plurality of shower plates 10 are formed by a first shower plate array 10A formed by a shower plate 10 in which four shower plates 10 are arranged at equal intervals in the x-axis direction via the fixing member 30. Further, a plurality of shower plates 10 are formed by a shower plate 10 which is arranged at equal intervals in the x-axis direction via the fixing member 30. Further, in the y-axis direction orthogonal to the x-axis direction, the first shower plate row 10B is placed adjacent to the first shower plate row 10A. The first shower plate row 10A and the second shower plate row 10B are alternately formed in the y-axis direction. Further, with respect to the shower plate 10 of the first shower plate row 10A, the shower plate 10 of the adjacent second shower plate row 10B is biased in the y-axis direction. Although the amount of this bias is not limited thereto, it is preferably half of the width of the shower plate 10 in the y-axis direction.

Here, the meaning of shifting the position of the shower plate 10 between adjacent shower plate rows will be described. In the shower plate 10 which is a dielectric material, standing waves are formed due to propagation of surface waves, and unevenness occurs in the plasma. Therefore, if the shower plate 10 is arranged in a checkerboard pattern, the distribution of the plasma around the substrate to be subjected to the plasma treatment tends to be uneven, due to the unevenness of the plasma in the dielectric. Therefore, if the shower plates 10 which are dielectric materials are arranged one by one in a wide range as in the present embodiment, the distribution of the plasma around the substrate can be made more uniform. More specifically, in the lower surface of the lower plate portion 13 of the shower plate 10 which is a dielectric material, the plasma density is not uniform, and generally, it is at the central portion of the shower plate 10 and the plasma density is It is a non-uniform distribution. It is assumed that the outer shape of the shower plate 10 is square, and the arrangement pitch of the shower plates 10 arranged vertically and horizontally is set to P. In the case where the shower plates 10 are arranged side by side in a checkerboard pattern, the center of the shower plate 10 (the portion having the highest plasma density) and the portion farthest from the center of the adjacent shower plate 10 (plasma) The distance between the lowest density parts is P/√2≒0.707P. On the other hand, when each deviates from the wide When halfway up the side-by-side situation, the distance is 5P/8=0.625P, which is smaller when it is more side by side than the checkerboard grid. Further, in the vicinity of the shower plate 10, although the plasma is not uniform, it is uniform to some extent until it is diffused to the substrate where the plasma treatment is to be performed. Since the shower plate 10 is side-by-side offset by half, the distance between the portion where the plasma density is high and the portion where the plasma is low is short, so that the plasma of the periphery of the substrate can be made. The distribution becomes more uniform.

Next, the meaning of separately providing the microwave supply unit 70 for each of the grooves 211 (guide waves WG) will be described. If the microwave is propagated to the shower plate 10 through the waveguide WG, standing waves are generated not only in the shower plate 10 but also in the waveguide WG. It is assumed that if a plurality of openings (grooves) are formed at the waveguide, the intensity of the microwave propagating at the opening (groove) changes depending on the phase and intensity of the standing wave at the position of each groove. In this case, it is almost impossible to propagate microwaves of the same intensity and the same phase from all the slots. On the other hand, in the present embodiment, since the microwave supply unit 70 including the integrator and the microwave power supply is provided at each of the grooves 211 (the waveguide WG), even if the conditions of the plasma (load) are changed, It is also possible to constantly propagate microwaves of the same intensity and phase from all the grooves 211 to the shower plate 10. As a result, the distribution of the plasma can be made more uniform between the plurality of shower plates 10.

Next, the optimization of the gas discharge holes of the shower plate will be described. In order to improve the uniformity of the distribution of the plasma, it is necessary to The occurrence of the discharge at the gas flow path suppresses and promotes the generation of radicals. To achieve this, the size and aperture ratio of the gas discharge holes 11 of the shower plate 10 are important. In order to suppress the generation of the discharge at the gas flow path 14, it is preferable to increase the pressure of the gas flow path as much as possible, for example, 300 Torr or more. On the other hand, in order to promote the generation of radicals, it is preferable to reduce the gas blowing speed from the gas discharge hole 11 as much as possible, for example, to 1 m/sec or less. Here, between the diameter of the gas discharge hole 11 and the density (1) of the gas discharge hole 11 and the pressure (2) of the gas flow path 14, there is a general relationship as shown in the graph of Fig. 5. Therefore, in order to achieve the above-described gas blowing flow rate under a pressure of 300 Torr, it is necessary to set the length of the gas discharge hole 11 to 4 mm, the diameter of the gas discharge hole 11 to 40 mm, and the aperture ratio to 0.127. . For example, in the case of a plate made of alumina of 100 mm × 120 mm, it is only necessary to form about 1.2 megawatts of gas discharge holes 11.

Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. As long as there is a general knowledge in the technical field to which the present invention pertains, it is obvious that various modifications and corrections can be made within the scope of the technical idea described in the scope of the patent application, and it should be understood that These are of course within the technical scope of the present invention.

20‧‧‧Connected dielectric

50‧‧‧guide tube

60‧‧‧ coaxial tube

70‧‧‧Microwave supply unit

210‧‧‧Upper cover

Claims (2)

A plasma processing apparatus comprising: a dielectric material disposed on a common plane and having a plurality of dielectric layers; and a microwave that propagates through the opening to the plurality of dielectric materials a plurality of waveguides; and a microwave supply unit that supplies a plurality of mutually independent microwaves to the plurality of waveguides, wherein each of the plurality of dielectrics is provided to be used to plasmaize a plurality of gas discharge holes from the lower surface of the gas, wherein the plurality of dielectrics form a first dielectric matrix formed of the dielectric arranged in a first direction, and are arranged in the foregoing a second dielectric column arranged in the first direction and in a second direction orthogonal to the first direction, and disposed adjacent to the first dielectric column, The dielectric forming one of the first and second dielectric columns is disposed to be biased in the first direction with respect to the other dielectric. A plasma processing method characterized in that in a container in which a plasma generating mechanism is provided, a step of: facing a target object facing a lower surface of the first and second dielectric columns is performed a method for setting; and passing the plurality of waveguides from the plurality of microwave supply units And the step of, in the foregoing plurality of dielectrics, propagating the microwaves of the same phase and the same intensity; and the step of plasma-reducing the gas discharged from the plurality of gas discharge holes by the plasma generating mechanism, the electricity The slurry generating mechanism includes: a dielectric material disposed on a common plane and having the plurality of dielectric materials; and a plurality of dielectrics that propagate through the opening to each of the plurality of dielectric materials a waveguide, and a microwave supply unit that supplies the plurality of microwaves independently of each other for the plurality of waveguides, wherein each of the plurality of dielectrics has a gas for pulverizing the gas from the foregoing a plurality of gas discharge holes that are disposed below, wherein the plurality of dielectrics form the first dielectric column formed of the dielectric in the first direction, and are arranged in the first The second dielectric column which is formed by the dielectric in one direction and which is disposed adjacent to the first dielectric column in a second direction orthogonal to the first direction, form The dielectric of one of the first and second dielectric columns is placed in a biased manner in the first direction with respect to the other dielectric.