KR20050059858A - Power supply system comprising a plurality of electrode blocks - Google Patents

Abstract

The present invention, RF power supply; An impedance matcher having one end connected to the RF power supply and matching an impedance; A plasma electrode composed of a plurality of electrode blocks; One end is connected to the impedance matching device, and the other end provides a power supply system including a plurality of parallel lines connecting the plurality of electrode blocks in parallel. In another aspect, the present invention provides a power supply system in which a plurality of RF power is connected to each of a plurality of electrode blocks.

According to the present invention, process uniformity can be improved by improving the uniformity of the plasma irrespective of the size of the substrate, and it is possible to actively cope by adjusting the inductor even if the process conditions are changed in the same chamber. According to the present invention, even if the gas flow is asymmetric, a uniform plasma density can be obtained.

Description

Power supply system comprising a plurality of electrode blocks

The present invention relates to an apparatus for manufacturing a liquid crystal display device, and more particularly, to a power supply system for supplying RF power in a plasma processing equipment.

In general, to manufacture a liquid crystal display device, a thin film deposition process for depositing a dielectric material or the like on a substrate as a thin film, a photolithography process for exposing or hiding selected areas of the thin films using a photosensitive material, The etching process of removing the thin film and patterning it as desired and the cleaning process to remove residues are repeated several times. Each of these processes is performed in a chamber having an optimal environment for the process. .

Recently, many plasma processing equipments are used to excite process gas into active species in a plasma state using high frequency power, and then perform deposition, etching, and cleaning processes using such high frequency power. To form a strong electric field between the two electrodes, and to generate plasma active species by collision of electrons and neutral gas accelerated by the electric field, and a chamber coil installed inside the chamber by an antenna coil installed outside the chamber. It can be divided into an inductive coupling method for generating plasma active species using an induced magnetic field induced in and coupled to the induction field.

1 illustrates a capacitively coupled plasma processing apparatus, wherein the chamber 10 forms a constant reaction space therein, and the substrate 30 is disposed inside the chamber 10. It is connected to the susceptor 20, the showerhead 40 for injecting the process gas from the top of the susceptor 20, and connected to an external gas storage unit (not shown) to inject the process gas into the showerhead 40 It includes a gas inlet pipe (80).

In addition, a plasma electrode 50 positioned above the shower head 40 to apply RF power to the process gas, an RF power source 60 supplying RF power to the plasma electrode 50, and the plasma electrode 50. Path impedance is matched so that the maximum power can be applied, and an impedance matching box 70 is disposed between the plasma electrode 50 and the RF power supply 60. In this case, the electrode corresponding to the plasma electrode 50 becomes a grounded susceptor 20, and the plasma electrode 50 may be formed integrally with the shower head 40.

When the plasma processing equipment is configured as a circuit diagram in which RF power is transmitted in the configuration as shown in FIG. 1, the configuration as shown in FIG. 2 is obtained. The capacitor 50 represents a plasma electrode, and more precisely, the plasma electrode inside the chamber 10. The capacitance between the 50 and the grounded susceptor 20 is shown.

Referring to the operation of the plasma processing equipment having such a configuration, first, when the substrate 30 is loaded into the chamber 10 through the door not shown and placed in the susceptor 20, from the gas inlet pipe 80 The supplied process gas is injected into the chamber 10 through the shower head 40. In this case, when RF power is applied to the plasma electrode 50, active species generated by the collision of the accelerated electrons and the neutral gas are incident on the substrate 30 to perform a deposition or etching process.

In such a plasma processing equipment, the most influential variable on the process uniformity is whether or not the uniformity of the active species generated on the upper part of the substrate 30 is uniform, and the uniform distribution of the active species results in the uniform injection of the process gas, It can be ensured by the uniform generation of the plasma.

Among these methods, various methods have been attempted to uniformly generate the plasma according to the present invention. First, in order to secure uniformity of the RF electric field formed between the plasma electrode 50 and the susceptor 20, the plasma electrode ( 50) there is a method for arranging so that RF power can be supplied to the center. In FIG. 1, in order to supply RF power to the center of the plasma electrode 50, the RF power source 60 is connected to a gas inlet pipe 80 passing through the center of the plasma electrode 50. This ensures maximum symmetry of the RF electric field.

As a second method, as disclosed in Korean Patent Laid-Open Publication No. 2001-0071873, a method of simultaneously applying a single frequency power source or a multi-frequency power source to several symmetrical points of the plasma electrode 50 via a plurality of capacitors. to be. FIG. 3 shows a circuit configuration in such a case, and the RF power supply 60 is applied to the plasma electrode 50 via the impedance matcher 70 and various capacitors C ₁ , C ₂ , and C ₃ . . By adjusting the capacitance of the capacitor located at a portion where the plasma density is too high or too low than the average, the applied RF power is added and subtracted, thereby more actively controlling the plasma uniformity.

However, in the case of liquid crystal display devices in recent years, since the substrate is becoming larger in size, there is a limit in securing the uniformity of the plasma only by such a method.

In other words, since RF power supplied to the plasma electrode has a standing wave component on the surface of the plasma electrode, non-uniform distribution of RF power is inevitable. In the fourth and fifth generations, the size of the substrate is relatively small compared to the wavelength of the standing wave. This effect could therefore be ignored.

However, even in the case of the 7th generation substrate, which has recently entered the commercialization stage, the size of the substrate is almost close to the wavelength of the RF power. In such a substrate, the RF power is applied to the center of the electrode as described above. There is a problem that it is difficult to secure the uniformity of plasma alone. In addition, the method of applying the RF power symmetrically to various places of the plasma electrode by using a plurality of capacitors is complicated in the configuration of the device, difficult to maintain, and the cost of the capacitor is high due to the characteristics of the equipment requiring high power RF power. There is a problem that increases the manufacturing cost is quite expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a method of improving plasma uniformity more easily in a plasma processing apparatus for processing a large area substrate.

The present invention to achieve the above object, RF power source; An impedance matcher having one end connected to the RF power supply and matching an impedance; A plasma electrode composed of a plurality of electrode blocks; One end is connected to the impedance matching device, and the other end provides a power supply system including a plurality of parallel lines connecting the plurality of electrode blocks in parallel.

The present invention also provides a plurality of RF power supply; A plurality of impedance matchers, one end of each of which is connected to the RF power source and for matching impedance; A plasma electrode composed of a plurality of electrode blocks; Provided is a power supply system including a plurality of lines connecting each of the plurality of electrode blocks and the plurality of impedance matchers.

The plurality of electrode blocks provide a power supply system including an inner electrode block having a flat plate shape and at least one outer electrode block surrounding an outer circumference of the inner electrode block.

The plasma electrode is a power supply system formed by horizontally coupling a plurality of square block-shaped electrode blocks

One or more of the parallel connection lines provide a power supply system in which an inductor is installed.

One or more of the lines provide a power supply system in which an inductor is installed.

The inductor provides a power supply system that is a variable inductor.

It provides a power supply system in which an insulator for electrical insulation is inserted between the plurality of electrode blocks.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention; In addition, the embodiment of the present invention relates to a PECVD equipment or an etcher for injecting a process gas in the chamber and exciting it in a plasma state to perform a process on a substrate, so that it is applicable to not only LCD manufacturing equipment but also semiconductor manufacturing equipment. It can be. Therefore, the substrate mentioned below includes not only a glass substrate but also a semiconductor wafer, and for the convenience of description, the following description will be made using PECVD equipment as an example.

4 illustrates an electrode 100 composed of a plurality of electrode blocks according to a first embodiment of the present invention, the first electrode block 110 having an opening in the center thereof, and the first electrode block 110. An insulator 200 inserted between the second electrode block 120 inserted into an opening of the second electrode block 120 and an inner wall of the first electrode block 110 and an outer wall of the second electrode block 120 to electrically insulate both electrode blocks. It is composed of

Since the first and second electrode blocks 110 and 120 are electrically insulated by the insulator 200, RF power must be supplied to each electrode block. In the drawing, both the outer periphery of the first electrode block 110 and the openings formed in the first electrode block 110 are shown as rectangles, but this is because the LCD substrate generally has a rectangular shape, but is not necessarily limited thereto. It can be transformed into various shapes. However, considering the plasma density, it is desirable to have at least a symmetrical shape.

FIG. 5 is a view illustrating a state in which the RF power supply 60 is connected to the plasma electrode 100 shown in cross section along the line I-I of FIG. 4, wherein the RF power supplied from the RF power supply 60 is an impedance matcher. Each of the edges is supplied to the first electrode block 110 and the second electrode block 120 at the center thereof, and the inductor L ₁ is connected to the first electrode block 110.

6, the first electrode block 110 and the second electrode block 120 may be represented by first and second capacitors C ₁ and C _2, respectively. The inductor L ₁ is connected to the first capacitor C ₁ corresponding to the block.

In this way, the plasma electrode is composed of a plurality of electrode blocks, and the inductor L ₁ is connected to vary the intensity of RF power applied to each electrode block, and the inductor L ₁ is configured as a variable inductor. In this case, it is possible to cope more actively to secure plasma uniformity under various process conditions.

For example, if the RF power flowing toward the first electrode block 110 is greater than the RF power flowing toward the second electrode block 120, the reactance X ₁ on the side of the first electrode block 110 may correspond to the second electrode block ( Should be less than the reactance (X ₂ )

X ₁ = ωL _1-1 / ωC _{1 ,} X ₂ = 1 / ωC ₂

Should be | X ₁ | <| X ₂ |,

Also, the matching circuit of the illustrated impedance matcher is for a capacitive load, so the sum of X ₁ and X ₂ connected in parallel should have a value that becomes a capacitive load, and thus X ₁ * X ₂ / (X ₁ + X ₂ ) <0.

Since the _first and second capacitors C ₁ and C ₂ have capacitance values that are fixed at the time of equipment design, the inductance values satisfying the above two conditions can be easily obtained. If the inductor L ₁ is installed accordingly, RF It is possible to actively regulate the power supply.

In this case, if the inductor L ₁ is taken to the zero limit, the inductor is removed in FIG. 6, so that the amount of RF power supplied depends on the size of the _first and second capacitors C ₁ and C ₂ . The size of the _first and second capacitors C ₁ and C ₂ depends mainly on the size of each electrode block. That is, the density of the plasma can be controlled by adjusting the size of each electrode block.

FIG. 7 is a plan view illustrating a general shape of the plasma electrode according to the first embodiment of the present invention, and the divided form is generalized as shown in FIG. The edges are divided into first, second, third, ... N-th electrode blocks 120, 130, 140..., 180, and each electrode block is electrically insulated by the insulator 200.

FIG. 8 is a cross-sectional view of the plasma electrode along line II-II of FIG. 7, and a configuration in which an RF power source is connected to each electrode block. The inductors L _1, L _{2 ,} L _3, L _N are connected to each other to adjust the magnitude of the RF power applied to each electrode block.

Although the drawings show that all the electrodes are connected to the inductor, the present invention is not limited thereto. Therefore, only one electrode block may be connected to the electrode block requiring the density control of the plasma, or the inductor may be omitted. In addition, by installing the first, _{second , third, ... N} inductors (L _1, L _2. L _{3, ....} L _N ) as a variable inductor can also control the RF power applied to each electrode block.

In addition, although the widths of the first, second, and third electrode blocks 110, 120, and 130 are shown to be the same, the width of the first, second, and third electrode blocks 110, 120, and 130 is not limited thereto.

9 illustrates a circuit configuration of the configuration of FIG. 8, wherein each of the electrode blocks 110, 120, 130, and 180 has a first capacitance C _1, C _2. C _{3, ...} C _N ).

FIG. 10 illustrates a state in which RF power is connected to each of the electrode blocks 110, 120, 130, and 180 of the plasma electrode of the general form according to the first embodiment of the present invention.

That is, the first RF power source 61 is connected to the first electrode block 110, the second RF power source 62 is connected to the second electrode block 120, and the third RF power source 63 is connected to the third electrode block 130. N-th RF power source 68 is connected to each of the N-th electrode block 180, and the first, second, third, ... N impedance matchers 71, 72, 73 are connected between each RF power source and each electrode. , ... 78) and the first, second and third ... N is the inductor _{(L 1, L 2. L} 3, .... L N) connection.

In order to control the density of the plasma, the inductor may not be connected to each electrode block in this way, or may not be installed at all, or may be connected to only one electrode block. Of course, the inductor can be configured as a variable inductor.

When RF power is independently supplied to each electrode block as described above, a phase adjuster may be provided to match the phase between the respective RF power supplies 61, 62, 63, and 64.

FIG. 11 is a view illustrating a second embodiment of the present invention, and a plurality of first, second, third, and fourth electrode blocks 310, 320, 330, 340, rather than a method in which one electrode block surrounds another electrode block as shown in FIG. 4 or 7. ) Is horizontally coupled to form a plasma electrode 300. Each electrode block is shown to have the same shape, but is not limited thereto, and various modifications are possible, and the number is not limited to four, of course. Even in this case, the interface of the electrode block must be electrically insulated by the insulator 100.

In FIG. 12, in which the RF power supply 60 is connected to a plasma electrode having a cross section along line III-III of FIG. 11, the RF power is connected to the impedance matcher 70 and the first, second, third, and fourth inductors. L _1, L _2. L _{3 and} L ₄ ) are shown connected to each electrode. The circuit configuration for this is the same as the drawing in which L _N is replaced with L ₄ in FIG. 9.

Even in this case, the output of RF power applied to each electrode can be adjusted by adjusting the inductance of each inductor or by configuring a variable inductor. By adjusting the size of the inductor or the size or shape of the electrode block as described above, it is possible to actively cope with plasma uniformity in various process environments, and to cope with asymmetric flow of process gas.

In the above description of the preferred embodiment of the present invention, various modifications or changes are possible by those skilled in the art and it will be obvious that such modifications or changes belong to the scope of the present invention as long as they include the technical idea of the present invention. .

According to the present invention, process uniformity can be improved by improving the uniformity of the plasma irrespective of the size of the substrate, and it is possible to actively cope by adjusting the inductor even if the process conditions are changed in the same chamber. According to the present invention, even if the gas flow is asymmetric, a uniform plasma density can be obtained.

1 is a schematic configuration diagram of a conventional plasma processing equipment

2 is a conceptual circuit diagram of FIG. 1.

3 is a circuit diagram illustrating RF power applied to a plasma electrode using a plurality of capacitors.

4 is a plan view of a plasma electrode according to a first embodiment of the present invention;

5 is a configuration diagram in which one RF power source is connected to the plasma electrode of FIG. 4;

6 is a conceptual circuit diagram of FIG. 5.

7 is a plan view showing a general shape of the plasma electrode according to the first embodiment of the present invention

8 is a configuration diagram in which one RF power source is connected to the plasma electrode of FIG. 7;

9 is a conceptual circuit diagram of FIG. 8.

10 is a configuration diagram in which RF power is connected to each electrode block of the plasma electrode according to the first embodiment of the present invention;

11 is a plan view of a plasma electrode according to a second embodiment of the present invention

12 is a configuration diagram in which one RF power source is connected to the plasma electrode of FIG. 11;

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

10 chamber 20 susceptor

30 substrate 40 shower head

50, 100, 300: plasma electrode 60: RF power

70: impedance matcher 80: gas inlet pipe

200: insulator

Claims (8)

RF power supply; An impedance matcher having one end connected to the RF power supply and matching an impedance; A plasma electrode composed of a plurality of electrode blocks; One end is connected to the impedance matching device, the other end is a plurality of parallel lines for connecting the plurality of electrode blocks in parallel Power supply system including A plurality of RF power supplies; A plurality of impedance matchers, one end of each of which is connected to the RF power source and for matching impedance; A plasma electrode composed of a plurality of electrode blocks; A plurality of lines connecting each of the plurality of electrode blocks and the plurality of impedance matchers Power supply system including The method according to claim 1 or 2, The plurality of electrode blocks includes a plate-shaped inner electrode block and at least one outer electrode block surrounding the outer circumference of the inner electrode block. The method according to claim 1 or 2, The plasma electrode is a power supply system formed by horizontally coupling a plurality of square block-shaped electrode blocks The method of claim 1, At least one of the parallel connection lines is provided with an inductor The method of claim 2, At least one of the plurality of lines power supply system in which an inductor is installed The method according to claim 5 or 6, The inductor is a variable inductor power supply system The method according to claim 1 or 2, A power supply system in which an insulator for electrical insulation is inserted between the plurality of electrode blocks.