KR101507390B1 - capacitively coupled plasma reactor - Google Patents

Abstract

The capacitively coupled plasma reactor of the present invention includes a reactor body forming a plasma discharge space, and a capacitive coupling electrode assembly for forming a plasma in the plasma discharge space and forming one side of the plasma discharge space, Includes a common electrode having a plurality of trench regions and a plurality of split electrodes provided in the plurality of trench regions, and a plasma is generated in the trench region so as to surround the plurality of split electrodes. The capacitively coupled plasma reactor of the present invention can uniformly generate plasma of a large area by a plurality of capacitive coupling electrodes. In the parallel driving of the plurality of capacitive coupling electrodes, the current balance is automatically performed, so that the capacity coupling between the capacitive coupling electrodes is uniformly controlled, so that a high density plasma can be uniformly generated. Since the plurality of capacitive coupling electrodes can be easily expanded, it is possible to facilitate the large-sized plasma.

Capacitive coupled plasma, plasma reactor, current balance, laser, frequency, PECVD

Description

[0001] CAPACITIVELY COUPLED PLASMA REACTOR [0002]

The present invention relates to a capacitively coupled plasma reactor, and more particularly, to a capacitively coupled plasma reactor capable of generating plasma with a large area more uniformly, thereby increasing plasma treatment efficiency for a large-sized object to be treated, a plasma processing method using the same, And a semiconductor device manufactured thereby.

A plasma is a highly ionized gas containing the same number of positive ions and electrons. Plasma discharges are used in gas excitation to generate active gases including ions, free radicals, atoms, and molecules. Active gases are widely used in various fields and various semiconductor manufacturing processes for manufacturing devices such as integrated circuit devices, liquid crystal displays, solar cells, etc. can be used, for example etching, deposition, cleaning, ashing and so on.

Plasma sources for generating plasma are various, and examples thereof include capacitive coupled plasma and inductive coupled plasma using a radio frequency. Capacitively coupled plasma sources have the advantage that they have higher capacity for process control than other plasma sources because of their accurate capacitive coupling and ion control capability. However, when the capacitive coupling electrode is enlarged in order to process a substrate to be processed, the electrode may be deformed or damaged due to deterioration of the electrode. In this case, the electric field intensity becomes uneven, the plasma density may become uneven, and the inside of the reactor may be contaminated. Even in the case of the inductively coupled plasma source, it is difficult to uniformly obtain the plasma density when the area of the induction coil antenna is increased.

In recent years, the semiconductor manufacturing industry has been further improved due to various factors such as miniaturization of semiconductor devices, enlargement of substrates to be processed such as a silicon wafer substrate, a glass substrate or a plastic substrate for manufacturing a semiconductor circuit, A plasma processing technique is required. In particular, there is a demand for an improved plasma source and a plasma processing technique having excellent processing capability for a large-area substrate to be processed. Further, various semiconductor manufacturing apparatuses using lasers are being provided. A semiconductor manufacturing process using a laser is widely applied to various processes such as deposition, etching, annealing, cleaning, and the like on a substrate to be processed. The above-described problems also exist in the case of such a semiconductor manufacturing process using a laser.

The enlargement of the substrate to be processed leads to the enlargement of the overall production equipment. Large-scale production facilities increase the overall equipment area, resulting in increased production costs. Therefore, there is a demand for a plasma reactor and a plasma processing system capable of minimizing a facility area as much as possible. Particularly, in the semiconductor manufacturing process, productivity per unit area is one of the important factors affecting the final product price.

There are several processes in the process of manufacturing a semiconductor substrate. Since each process is performed in a separate process chamber, the target substrate on which one process is performed is transferred to a process chamber for proceeding to the next process. Such transfer between process chambers is a negative factor that increases the manufacturing time, so it needs to be shortened as much as possible. Or it would be highly desirable if different processes could proceed alternately in one process chamber.

An object of the present invention is to provide a capacitively coupled plasma reactor capable of uniformly generating and holding a large area of plasma, a plasma processing method using the same, and a semiconductor device manufactured thereby.

It is another object of the present invention to provide a capacitively coupled plasma reactor capable of uniformly generating a high-density plasma by uniformly controlling the current supply of the capacitive coupling electrode, a plasma processing method using the same, and a semiconductor device manufactured thereby.

It is still another object of the present invention to provide a capacitively coupled plasma reactor capable of uniformly generating high-density plasma with a large area, a plasma processing method using the same, and a semiconductor device manufactured thereby.

It is still another object of the present invention to provide a capacitively coupled plasma reactor capable of performing two or more substrate processing processes alternately continuously in one plasma reactor, a plasma processing method using the same, and a semiconductor device manufactured thereby.

According to an aspect of the present invention, there is provided a capacitively coupled plasma reactor. The plasma reactor of the present invention comprises: a reactor body forming a plasma discharge space; And a capacitive coupling electrode assembly for generating a plasma in the plasma discharge space, the capacitive coupling electrode assembly including a common electrode having a plurality of trench areas and a plurality of trench areas formed in the plurality of trench areas, And a plasma is generated in the trench region so as to surround the plurality of divided electrodes.

In one embodiment, the capacitive coupling electrode assembly may include two or more power sources selectively supplying different frequencies, and a switching circuit configured between the two or more power sources and the capacitive coupling electrode assembly to provide selective electrical connection. .

In one embodiment, the current dividing circuit regulates the distribution of the currents flowing to the plurality of divided electrodes.

In one embodiment, the current distribution circuit includes an automatic current balancing circuit that automatically adjusts the mutual balance of the currents supplied to the plurality of split electrodes.

In one embodiment, the common electrode includes a common electrode body and a plurality of gas ejection openings penetrating the common electrode body. The common electrode includes a plurality of gas injection openings formed on the outside of the reactor body, And a gas supply unit for supplying the process gas.

In one embodiment, the gas supply comprises two or more independent gas supply channels.

In one embodiment, the plurality of gas injection holes include a first group of gas injection holes formed in the plurality of trench areas and a second group of gas injection holes formed in addition to the plurality of trench areas.

In one embodiment, the apparatus further comprises a remote plasma generator for supplying a remote plasma into the interior of the reactor body through the gas supply.

In one embodiment, the capacitive coupling electrode assembly further includes a cooling channel.

According to the capacitively coupled plasma reactor of the present invention and the plasma processing method using the same, a large-area plasma can be uniformly generated by a plurality of capacitive coupling electrodes. In the parallel driving of the plurality of capacitive coupling electrodes, the current balance is automatically performed, so that the capacity coupling between the capacitive coupling electrodes is uniformly controlled, so that a high-density plasma can be uniformly generated. Since the plurality of capacitive coupling electrodes can be easily expanded, it is possible to facilitate the large-sized plasma.

In addition, since the capacitive coupling electrode assembly can be selectively driven by a selected one of two or more different frequencies, two or more different processes can be alternately performed successively in one plasma reactor, thereby maximizing productivity have.

For a better understanding of the present invention, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Therefore, the shapes and the like of the elements in the drawings can be exaggeratedly expressed to emphasize a clearer description. It should be noted that in the drawings, the same members are denoted by the same reference numerals. Detailed descriptions of well-known functions and constructions which may be unnecessarily obscured by the gist of the present invention are omitted.

1 is a view showing a plasma reactor according to a preferred embodiment of the present invention.

Referring to FIG. 1, a plasma reactor 10 according to a preferred embodiment of the present invention includes a reactor body 11, a gas supply unit 20, and a capacitive coupling electrode assembly 30. As will be described later in detail, the capacitive coupling electrode assembly 30 includes a planar common electrode 31 and a plurality of divided electrodes 33. Inside the reactor body 11, a substrate support 12 on which the substrate 13 is placed is provided. The capacitive coupling electrode assembly 30 is formed on the upper portion of the reactor body 11 so as to face the substrate support 12 and a gas supply unit 20 is formed thereon. An insulating member 25 is provided between the reactor body 11 and the capacitive coupling electrode assembly 30 to provide electrical insulation. The gas provided from the gas supply system 60 having the plurality of gas supply sources 61 is supplied to the inside of the plasma reactor 10 through the gas supply unit 20 and the capacitive coupling electrode assembly 30. The capacitive coupling electrode assembly 30 is selectively driven by two or more mutual frequencies to induce capacitively coupled plasma within the plasma reactor 10. Plasma processing is performed on the substrate 13 by plasma generated in the plasma reactor 10.

The plasma reactor 10 is provided with a reactor body 11 and a substrate support 12 in which a substrate 13 is placed. The reactor body (11) is connected to a vacuum pump (8). The reactor body 11 may be made of a metal material such as aluminum, stainless steel, or copper. Or a coated metal such as anodized aluminum or nickel plated aluminum. Or a composite metal in which carbon nanotubes are covalently bonded may be used. Or a refractory metal. Alternatively, the reactor body 11 may be wholly or partly made of an electrically insulating material such as quartz or ceramic. Thus, the reactor body 11 can be made of any material suitable for the intended plasma process to be performed. The structure of the reactor body 11 may have a suitable structure, for example, a circular structure or a rectangular structure, and any other structure for the uniform generation of the plasma and the substrate 13 according to the target substrate 13. The substrate 13 is a substrate such as a wafer substrate, a glass substrate, a plastic substrate, or the like, for manufacturing various devices such as a semiconductor device, a display device, a solar cell, and the like. In the embodiment of the present invention, the plasma reactor 10 is subjected to plasma treatment on the substrate 13 under a low-pressure state below atmospheric pressure. However, the capacitively coupled plasma reactor of the present invention can also be used in an atmospheric plasma processing system for treating a substrate to be processed at atmospheric pressure.

Inside the plasma reactor 10, a substrate support 12 for supporting the substrate 13 is provided. The substrate support 12 is connected to bias power sources 46 and 47 and biased. For example, two bias power sources 46, 47, which supply different radio frequency power sources, are electrically connected to the substrate support 12 through a common impedance matcher 48 (or each impedance matcher) . The double bias structure of the substrate support 12 facilitates plasma generation within the plasma reactor 10 and can further improve plasma ion energy control to improve process productivity. Or a single bias structure. Alternatively, the substrate support 12 may be deformed into a structure having a zero potential without the supply of bias power. And the substrate support 12 may comprise an electrostatic chuck. Or the substrate support 12 may comprise a heater. Basically, the substrate support table 12 is configured as a fixed or vertically movable structure. Or the substrate support 12 has a structure that is linear or rotationally movable parallel to the capacitive coupling electrode assembly 30. And may include a drive mechanism for linearly or rotationally moving the substrate support 12 in such moveable structure. An exhaust baffle (not shown) may be configured for uniform exhaust of the gas in the lower portion of the reactor body 11.

The plasma reactor 10 includes two or more power sources 40 and 41 and a switching circuit 44 and a control unit 66 for selectively supplying different frequencies to the capacitive coupling electrode assembly 30. In one embodiment, two first and second power sources 40 and 41 are provided. The first and second power sources 40 and 41 generate different frequencies f1 and f2, respectively. For example, the first power source 40 generates a frequency of 1 MHz or more, and the second power source 40 generates a frequency of less than 1 MHz. The first and second power sources 40 and 41 may be configured using a radio frequency generator capable of controlling the output without a separate impedance matcher. In this embodiment, the two first and second power sources 40 and 41 are provided. However, three or more power sources may be provided to generate three or more different radio frequencies. Alternatively, one power source capable of frequency modulation may be used.

A switching circuit 44 is provided between the first and second power sources 40, 41 and the capacitive coupling electrode assembly 30 to provide a selective electrical connection. The switching circuit 44 may be composed of, for example, a relay switch. The switching circuit 44 has two input terminals and one output terminal. The two input terminals of the switching circuit 44 are connected to the first and second power sources 40 and 41 through the first and second impedance matchers 42 and 43, respectively. The switching circuit 44 under the control of the control unit 66 performs a switching operation so that any one of the two input terminals is electrically connected to the output terminal. Thus, any one of the different radio frequencies f1 and f2 generated from the first and second power sources 40 and 41 is selectively supplied to the capacitive coupling electrode assembly 30. The control unit 66 controls the overall operation of the plasma reactor 10 by organically controlling the first and second power sources 40 and 41 and the switching circuit 44. The control unit 66 controls the gas supply system 60 so that at least one gas related to the process to be performed in the plasma reactor 10 is supplied to the interior of the reactor body 11. [

FIG. 2 is a timing chart for explaining how alternate frequencies are alternately supplied to the capacitive coupling electrode assembly for alternate process progression, and FIG. 3 is a timing chart for explaining a case where a thin film is alternately formed on the substrate to be processed Sectional view of the substrate to be processed.

2 and 3, the plasma reactor 10 alternately performs two different processes for the substrate 13 using the capacitive coupling electrode assembly 30 driven at different frequencies . For example, after the substrate to be processed is loaded into the interior of the reactor body 11, gas for proceeding the first process (P_ # 1) is supplied. The first frequency f1 generated from the first power source 40 is supplied to the capacitive coupling electrode assembly 30 to generate plasma and the first process P_ # 1 proceeds.

When the first process (P_ # 1) is completed, the supply of the first frequency (f1) is turned off and the gas for advancing the second process (P_ # 2) is supplied into the reactor body (11). The second frequency f2 generated from the second power source 41 is supplied to the capacitive coupling electrode assembly 30 to generate plasma and the second process P_ # 2 proceeds. The first and second power sources 40 and 41 are controlled by the control unit 66, and when one of them is in operation, the other is stopped.

The first process (P_ # 1) and the second process (P_ # 2) may be alternately repeated. The first and second processes P_ # 1 and P_ # 2 may be, for example, a plasma enhanced chemical vapor deposition (PECVD) process. As shown in FIG. 3, alternately repeated thin films L1 and L2 are deposited on the substrate 13 by the alternate repetitive process. In the first process (P_ # 1) and the second process (P_ # 2), the atmospheric pressure in the plasma reactor (10) may be the same or different atmospheric pressure, and the supplied gas may be the same or different. In the case of the process progress time, the same process progress time or different process progress time can be obtained.

Referring again to FIG. 1, the gas supply unit 20 is installed on the upper portion of the capacitive coupling electrode assembly 30. The gas supply unit 20 may include two or more independent gas supply channels to independently supply different gases to the inside of the plasma reactor 10. For example, the gas supply unit 20 may include an upper gas manifold 23 connected to the first gas inlet 21 to form one gas supply channel, and a second gas inlet (not shown) And a lower gas manifold (24) connected to the lower gas manifold (22). The upper and lower gas manifolds 23 and 24 are not shown in the figure, but may be provided with gas distribution plates for gas distribution. The upper and lower gas manifolds 23 and 24 are connected to a plurality of gas injection openings 32 and 34 formed in the capacitive coupling electrode assembly 30. The plurality of gas injection openings 32 and 34 are formed in the first group of gas injection openings 34 formed in the trench region 35 of the common electrode 31 of the capacitive coupling electrode assembly 30 and the trench regions 34 And a second group of gas injection orifices 32 formed in regions other than the gas injection orifices 35. The different gases input through the first and second gas inlets 21 and 22 pass through the upper gas manifold 23 and the lower gas manifold 24 and through the plurality of gas injection openings 32 and 34, And is evenly injected into the reactor 10. It is possible to separate and supply different gases independently to increase the efficiency of plasma processing. The first and second groups of gas injection openings 34 and 32 are formed at different heights in the reactor body 11. Therefore, the gas supplied through the first group of gas injection ports 34 is plasma discharged in the trench area 35 and the gas supplied through the second group of gas injection ports 32 is discharged in the region except the trench area 35 A plasma discharge is performed and a uniform plasma discharge is achieved.

A remote plasma generator 65 may be connected to the upper portion of the gas supply unit 20. The remote plasma generator 65 supplies, for example, active gas to the interior of the plasma reactor 10 to clean the interior of the plasma reactor 10. The gas supplied from the gas supply system 60 may be provided to the gas supply unit 20 via or not via the remote plasma generator 65. To this end, the gas supply path provided from the gas supply system 60 may include a plurality of gas valves 62, 63, 64. Further, the active gas generated from the remote plasma generator 65 may be supplied only to one gas supply channel of the gas supply unit 20 or both of the two gas supply channels.

4 and 5 are a perspective view and a cross-sectional view of the capacitive coupling electrode assembly.

4 and 5, the capacitive coupling electrode assembly 30 includes a plate-shaped common electrode 31 and a plurality of divided electrodes 33 for generating capacitively coupled plasma discharge in the plasma reactor 10 ). The common electrode 31 is opposed to the substrate support 12 to form the ceiling of the reactor body 11. The common electrode 31 has a plate-shaped common electrode body and a plurality of trench regions 35 formed in parallel on the bottom surface of the body. Each of the trench regions 35 has, for example, a dome-shaped structure, and the plurality of divided electrodes 33 has a cylindrical bar shape. The common electrode 31 is electrically grounded, and the plurality of divided electrodes 33 are connected in parallel to the current distribution circuit 50. The current distribution circuit 50 supplies the radio frequency f1 and f2 provided from either the first power source 40 or the second power source 41 via the switching circuit 44 to the plurality of split electrodes (33).

The gas input through the first gas inlet 21 is injected into the interior of the reactor body 11 through the second group of gas injection ports 34 via the upper gas manifold 23 and is injected into the second gas inlet 22 are injected into the interior of the reactor body 11 through the lower gas manifold 24 and through the first group of gas injection openings 34. That is, the gas jetting openings 34 of the first group are aligned with the center portion of the ceiling of the transient region 35, so that the gas flowing through the gas jetting openings 34 is divided into two parts and collides with the plurality of divided electrodes 33. Thus, a plasma is generated in the trench region 35 so as to surround the plurality of divided electrodes 33.

The trench region 35 of the common electrode 31 and the plurality of divided electrodes 33 have a linear structure arranged in parallel, but can be modified into various shapes. For example, the common electrode 31 is installed to constitute the ceiling of the reactor body 11, but may constitute the sidewall of the reactor body 11 in order to increase the plasma treatment efficiency. Or both the ceiling and the side wall. The common electrode 31 and the plurality of divided electrodes 33 can be variously modified in terms of the planar structure, the three-dimensional structure, the cross-sectional structure, and the number and length in order to increase the plasma generation efficiency and the plasma treatment efficiency. The capacitive coupling electrode assembly 30 may have a cooling channel or a heating channel for proper temperature control.

1, the current of the radio frequency (f1 or f2) generated from the first or second power source 41 or 42 is supplied to the plurality of capacitive coupling electrode assemblies 30 through the current distribution circuit 50 Divided electrodes 33 to induce a capacitively coupled plasma in the plasma reactor 10. [ The current distribution circuit 50 may be configured as an automatic current balance circuit that automatically adjusts the balance of the current supplied to the plurality of split electrodes 33. [ The automatic current balancing circuit automatically balances the respective currents supplied to the plurality of divided electrodes 33. Therefore, not only a large-area plasma can be generated by the plurality of divided electrodes 33, but also the current balance is automatically made when the plurality of capacitive coupling electrodes 33 are driven in parallel, And can maintain.

6 is a circuit diagram of the current distribution circuit.

Referring to FIG. 6, the current distribution circuit 50 includes a plurality of transformers 52 connected in series to constitute an automatic current balance circuit. The plurality of transformers 52 are connected in parallel to the plurality of divided electrodes 33 in parallel so as to constitute an automatic current balancing circuit that automatically drives each electrode in parallel and balances the current. The primary side of the plurality of transformers 52 is connected in series between a power input terminal (output terminal of the switching circuit 44) to which a radio frequency is inputted and a ground, and one end of the secondary side is connected to a corresponding plurality of divided electrodes 33 And the other ends are commonly grounded. The plurality of transformers 52 divides the voltage between the power input terminal and the ground equally and outputs a plurality of divided voltages to the plurality of divided electrodes 33 corresponding to each other.

At this time, since the currents flowing to the primary side of the plurality of transformers 52 are the same, the respective powers supplied to the plurality of divided electrodes 33 are also the same. When the impedance of any one of the plurality of divided electrodes 33 is changed and a change in the amount of current is generated, a plurality of transformers 52 operate as a whole to achieve a current balance. Thus, the currents supplied to the plurality of divided electrodes 33 are uniformly and continuously controlled automatically. In the plurality of transformers 52, the winding ratio of the primary side and the secondary side is basically set to 1: 1, but this can be changed.

Although not shown in the drawings, the current distribution circuit 50 including the automatic current balancing circuit as described above may include a protection circuit for preventing an excessive voltage from being generated in the plurality of transformers 52. [ The protection circuit prevents the transient voltage from being increased in the transformer due to a defect such as that any one of the plurality of transformers 52 is electrically opened. The protection circuit of this function may be realized by connecting a varistor to both ends of each of the plurality of transformers 52 or by using a constant voltage diode such as a zener diode . A compensation circuit for compensation of a leakage current, such as the compensation capacitor 51, may be added to the current distribution circuit 50 for each transformer 52. As such, the current distribution circuit can add another type of deformation or circuit configuration for a more complete current distribution.

The above-described capacitive coupled plasma reactor of the present invention, the plasma processing method using the same, and the semiconductor device manufactured by the method are merely illustrative, and those skilled in the art will appreciate that It will be appreciated that various modifications and equivalent embodiments are possible. Accordingly, it is to be understood that the present invention is not limited to the above-described embodiments. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

 The capacitively coupled plasma reactor of the present invention and the plasma processing method using the same can be very usefully used for manufacturing various kinds of semiconductor devices such as a semiconductor integrated circuit, a flat panel display, and a solar cell.

1 is a view showing a plasma reactor according to a preferred embodiment of the present invention.

FIG. 2 is a timing diagram illustrating how different frequencies are alternately supplied to the capacitive coupling electrode assembly for alternate process progression.

3 is a cross-sectional view of a substrate to be processed which exemplarily shows a thin film alternately formed on a substrate to be processed by an alternate process.

4 and 5 are a perspective view and a cross-sectional view of the capacitive coupling electrode assembly.

6 is a circuit diagram of the current distribution circuit.

Description of the Related Art [0002]

8: Vacuum pump 10: Plasma reactor

11: reactor body 12: substrate support

13: substrate to be processed 20: gas supply unit

21: first gas inlet 22: second gas inlet

23: upper gas manifold 24: lower gas manifold

25: Insulation member 30: Capacitive coupling electrode assembly

31: common electrode 32: gas jet opening

33: split electrode 34: gas jet opening

35: trench region 40: first power source

41: second power source 42, 43: impedance matcher

44: switching circuit 46, 47: bias power source

48: Impedance matching circuit 50: Current distribution circuit

51: compensation capacitor 52: transformer

60: gas supply system 61: gas supply source

62, 63, 64: gas valve 65: remote plasma generator

66:

Claims (9)

A reactor body forming a plasma discharge space; And And a capacitive coupling electrode assembly for generating a plasma in the plasma discharge space and forming one side of the plasma discharge space, The capacitive coupling electrode assembly A plurality of trench regions, a first group of gas injection holes formed in the trench region, and a second group of gas injection holes formed in a portion except for the trench region so as not to be mixed with the process gas supplied through the first group of gas injection holes A common electrode connected to the ground; And And a plurality of split electrodes provided in the plurality of trench regions and selectively supplied with different frequencies from two or more power sources, Wherein the process gas supplied through the first group of gas injection orifices is discharged in the trench region and the process gas supplied through the second group of gas injection orifices is discharged at a portion other than the trench region A capacitively coupled plasma reactor. delete The method according to claim 1, And a current distribution circuit for controlling the distribution of the currents flowing to the plurality of split electrodes. The method of claim 3, Wherein the current distribution circuit comprises an automatic current balancing circuit that automatically adjusts the mutual balance of the currents supplied to the plurality of split electrodes. delete delete delete The method according to claim 1, Further comprising a remote plasma generator for supplying a remote plasma into the interior of the reactor body. The method according to claim 1, Wherein the capacitive coupling electrode assembly further comprises a cooling channel.

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