KR100845891B1 - Plasma reactor having multi loop core plasma generator - Google Patents

Abstract

A plasma reactor with a multi-loop core plasma generator is disclosed. A plasma reactor with a multi-loop core plasma generator of the present invention includes a multi-loop core plasma generator comprising a multi-loop core and primary windings, a power supply for supplying current to the primary windings, and a current supplied from the power supply. And a current balancing circuit that distributes and distributes the current to the primary windings of the multiple loop core. According to the plasma reactor with the multi-loop core plasma generator of the present invention, in the plasma reactor with the multi-loop core plasma generator including the multi-loop core and the primary winding, the balance of the current supplied to the primary winding of the multi-loop core is balanced. It can be adjusted to obtain a uniform high density plasma of a large area.

Plasma, transformer, inductive coupling, current balancing

Description

Plasma reactor with multi-loop core plasma generator {PLASMA REACTOR HAVING MULTI LOOP CORE PLASMA GENERATOR}

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

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

2 is a diagram illustrating an example of a plasma reactor having a multi-loop core plasma generator.

3 is a vertical sectional view of the multi-loop core plasma generator of FIG. 2.

4A and 4B are diagrams showing examples of a multi-loop core.

5 shows another example of a plasma reactor having a multi-loop core plasma generator.

6 is an exploded perspective view illustrating the multi-loop core plasma generator of FIG. 5.

FIG. 7 is a top cross-sectional view of the multi-loop core plasma generator of FIG. 5.

8 and 9 show still other examples of a plasma reactor having a multi-loop core plasma generator.

10 to 12 are diagrams illustrating one embodiment of a current balancing circuit and variations thereof.

13 and 14 show other embodiments and modifications of the current balancing circuit.

15 is a view showing an example in which the configuration of the current variable controller is configured with a variable capacitor.

16 is a circuit diagram showing another embodiment of the current balancing circuit.

17 is a detailed circuit diagram of the current balancing circuit of FIG. 16.

18 is a view showing a modification of the current balance divider of FIG.

19A through 19C are circuit diagrams illustrating modifications of a power transformer.

20 is a circuit diagram showing another modified example of the current balancing circuit.

21 is a block diagram showing a control circuit configuration for controlling a current balancing circuit.

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

100: power supply circuit 110: radio frequency generator

120: impedance matcher 200: current balance circuit

300: vacuum chamber 310: gas supply source

320: multi-core plasma generator 330: substrate support

The present invention relates to a transformer plasma source, and more particularly, to a plasma reactor having a multi-loop core plasma generator capable of generating a large area of uniform plasma.

Plasma is a highly ionized gas containing the same number of positive ions and electrons. Plasma discharges are used for gas excitation to generate active gases containing ions, free radicals, atoms, molecules. The active gas is widely used in various fields and is typically used in a variety of semiconductor manufacturing processes such as etching, deposition, cleaning, ashing, and the like.

There are a number of plasma sources for generating plasma, and the representative examples are capacitive coupled plasma and inductive coupled plasma using radio frequency.

Capacitively coupled plasma sources have the advantage of high process productivity compared to other plasma sources due to their high capacity for precise capacitive coupling and ion control. On the other hand, since the energy of the radio frequency power supply is almost exclusively connected to the plasma through capacitive coupling, the plasma ion density can only be increased or decreased by increasing or decreasing the capacitively coupled radio frequency power. However, increasing radio frequency power increases ion bombardment energy.

On the other hand, the inductively coupled plasma source can easily increase the ion density with the increase of the radio frequency power source and the ion bombardment is relatively low, so it is known to be suitable for obtaining high density plasma. Therefore, inductively coupled plasma sources are commonly used to obtain high density plasma. Inductively coupled plasma sources are typically developed using a method using a radio frequency antenna (RF antenna) and a method using a transformer.

Inductively coupled plasma sources using a transformer can obtain a high density of plasma relatively easily, but the plasma uniformity is affected by structural features. Therefore, efforts have been made to improve the plasma source structure to obtain a uniform high density plasma.

In the recent semiconductor manufacturing industry, plasma processing technology has been further improved due to various factors such as ultra-miniaturization of semiconductor devices, the enlargement of silicon wafer substrates for manufacturing semiconductor circuits, the enlargement of glass substrates for manufacturing liquid crystal displays, and the emergence of new target materials. This is required. In particular, there is a need for improved plasma sources and plasma processing techniques that have good processing capabilities for large area workpieces.

Plasma reactors employing a plurality of transformer coupling structures have been proposed to obtain large area plasma. However, if a plurality of transformers are used, a large area plasma can be obtained, but it is not easy to obtain a uniform plasma.

SUMMARY OF THE INVENTION An object of the present invention is a plasma reactor having a multi-loop core plasma generator including a multi-loop core and a primary winding, in which a plasma can be obtained by adjusting a balance of current supplied to the primary winding of the multi-loop core. The purpose is to provide a reactor.

One aspect of the present invention for achieving the above technical problem relates to a plasma reactor. The plasma reactor of the present invention comprises: a multi loop core plasma generator comprising a multi loop core and primary windings; A power supply for supplying current to the primary windings; And a current balancing circuit which distributes and distributes the current supplied from the power supply to the primary windings of the multiple loop core.

In one embodiment, the current balancing circuit comprises: a current balance divider having a plurality of transformers each corresponding to a multiple loop core, wherein the plurality of transformers comprise: a radio frequency input between a primary side connected to a power source and ground; Connected in series, the secondary side being connected to the primary winding of the corresponding multiple loop core; Divide the voltage between the radio frequency input and ground; A plurality of divided voltages are supplied to the primary windings of the corresponding multiple loop cores, respectively.

In one embodiment, the current balance divider comprises: variable means for varying the turns ratio of the secondary side of the plurality of transformers.

In one embodiment, the current balance divider comprises: an intermediate tap configured on the secondary side of the plurality of transformers and connected to ground.

In one embodiment, the current balancing circuit comprises: a current varyer for variably controlling the current supplied to the primary windings of the multiple loop core; And a current balance divider that balances respective currents supplied to the primary windings of the multi-loop core, the current balance divider comprising: a plurality of induction coils connected to the primary windings of the multi-loop core; And a magnetic core to which a plurality of induction coils are commonly wound.

In one embodiment, a variable means for varying the number of turns of the plurality of induction coils.

In one embodiment, the current balancing circuit comprises: a power transformer connected to a power supply; And applying the secondary voltage of the power transformer to divide the voltage into a plurality of voltages, and applying the divided voltage to one end of the primary windings of the multiple loop core, and balancing the current values inputted to the primary windings of each multiple loop core. And a current balance divider for distributing the amount of current to achieve.

In one embodiment, the power transformer has a middle tap grounded on a secondary side and outputs a constant voltage V_p and a negative voltage V_n; The current balancing circuit receives the constant voltage of the power transformer and divides it into a plurality of voltages and inputs them to one end of the primary windings of the multiple loop core; The negative voltage of the power transformer is commonly applied to the other end of the primary windings of the multiple loop core.

In one embodiment, the current balance divider comprises: a plurality of transformers each corresponding to primary windings of a multiple loop core, the plurality of transformers: the primary side connected in series between the secondary side of the power transformer and ground The secondary side is connected to the primary windings of the corresponding multiple loop core; Divide the voltage between the secondary side of the power transformer and ground; A plurality of divided voltages are supplied to the primary windings of the corresponding multiple loop cores, respectively.

In one embodiment, the current balance divider comprises: variable means for varying the turns ratio of the secondary side of the plurality of transformers.

In one embodiment, the apparatus comprises variable means for varying the ratio of the constant voltage and the negative voltage of the power transformer.

In one embodiment, the apparatus comprises variable means for varying the ratio of the constant voltage and the negative voltage of the power transformer and respective voltage levels.

In one embodiment, the power transformer comprises: a middle tap configured on the secondary side and grounded; And a multi-tap switching circuit having a switch operable to switch any one of the multi-tap and the multi-tap configured between the intermediate tap and the constant voltage output stage to a current balanced divider, wherein the current balanced divider comprises a multi-tap switching circuit of the constant voltage output stage of the power transformer. The voltage between the switches is divided and applied to one end of the primary windings of the multiple loop core.

In one embodiment, the current balance divider includes a protection circuit for preventing a transient voltage from occurring.

In one embodiment, a control unit for controlling the current balance circuit to variably control the power supplied to the primary windings of the multiple loop core.

In an embodiment, the controller controls the current balancing circuit based on at least one of a user control input, process condition data, and a plasma state detection value provided from a plasma state monitoring circuit for detecting a plasma state.

In one embodiment, a substrate support on which a substrate to be processed to be processed by plasma gas generated by a multi-loop core plasma generator is placed; And a bias power supply for supplying a bias power to the substrate support, wherein the bias power supply has a bias structure of either single bias or dual bias.

In one embodiment, a substrate support on which a substrate to be processed to be processed by plasma gas generated by a multi-loop core plasma generator is placed; The substrate support has no supply of bias power.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the embodiments of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description. In understanding the drawings, it should be noted that like parts are intended to be represented by the same reference numerals as much as possible. And detailed description of known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention is omitted.

(Example)

Hereinafter, by describing the preferred embodiment of the present invention with reference to the accompanying drawings, a plasma reactor having a multi-loop core plasma generator of the present invention will be described in detail. In addition, in the drawings, the same reference numerals are denoted together for components that perform the same function.

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

A plasma reactor according to a preferred embodiment of the present invention includes a multi-loop core plasma generator 320 comprising multiple loop cores C1, C2, C3 and primary windings P1, P2, P3. The multiple loop cores C1, C2 and C3 and the corresponding primary windings P1, P2 and P3 constitute a plurality of plasma generating units G1, G2 and G3. The multi-loop core plasma generator 320 generates induced electromotive force for plasma generation into the vacuum chamber 300 of the plasma reactor. The plasma reactor has a power supply 100 and a current balance circuit 200 for supplying radio frequencies. The power supply 100 includes a radio frequency generator 110 and an impedance matcher 120 for generating radio frequencies.

The primary windings P1, P2, P3 of the multiple loop cores C1, C2, C3 are connected in parallel to the current balancing circuit 200, and the current supplied from the power supply 100 is the current balancing circuit 200. Through the current balance to the primary windings (P1, P2, P3) of the multiple loop core (C1, C2, C3) is distributed and supplied. Therefore, a more uniform high density plasma is generated in the vacuum chamber 300 by the plurality of plasma generating units G1, G2, and G3. A more detailed description of the current balancing circuit will be described later. The radio frequency generator 110 may be configured using a radio frequency generator capable of controlling the output power without a separate impedance matcher.

The substrate support 330 on which the substrate W is placed is provided in the vacuum chamber 300. The substrate W to be processed is, for example, a silicon wafer substrate for producing a semiconductor device or a glass substrate for producing a liquid crystal display or a plasma display. The vacuum chamber 300 is connected to the gas supply source 310 to receive a process gas. The vacuum chamber 300 is connected to the vacuum pump 315 so that the gas is exhausted by the vacuum pump 315 after the process of the vacuum chamber 300.

The vacuum chamber 300 is rebuilt from metallic materials such as aluminum, stainless steel, and copper. Or coated metal, for example anodized aluminum or nickel plated aluminum. Or refractory metal. Alternatively, it is possible to rewrite the chamber body 301 entirely with an electrically insulating material such as quartz, ceramic, or other materials suitable for carrying out the intended plasma process. In order to prevent the eddy current from being generated in the vacuum chamber 300 by the induced electromotive force transmitted from the multi-loop core plasma generator 320, an electrical insulation layer may be provided in a required portion of the vacuum chamber 300. The ceiling of the vacuum chamber 300 has a flat plate structure as a whole, but may have a domed structure. Alternatively, it may be modified into any other type of structure for uniform generation of plasma.

Although not illustrated in detail, the multi-loop core plasma generator 320 is configured with a cooling water supply channel. When different types of process gases are supplied from the gas source 310, they may be independently supplied to the vacuum chamber 300 through two independent gas supply channels. In addition, at least one gas distribution diaphragm may be configured in the vacuum chamber 300 to uniformly distribute the process gas. Multiple loop cores C1, C2, C3 may be configured using one single magnetic core, but may also be configured using multiple magnetic core pieces. In the case of using a plurality of magnetic core operations, a nonmagnetic material layer such as an insulating material may be inserted into the assembly surface of each piece to form a connection.

The vacuum chamber 300, the multi-loop core plasma generator 320, and the multi-loop cores C1, C2, and C3 may be implemented in various forms. Some examples will be described with reference to FIGS. 2 to 9.

2 is a diagram illustrating an example of a plasma reactor having a multi-loop core plasma generator. Referring to FIG. 2, the vacuum chamber 300 of the plasma reactor according to an example includes a lower chamber 300-1, an upper chamber 300-2, and a multiple loop core plasma generator 320 therebetween. A substrate support 330 and a gas outlet (not shown) are provided in the lower chamber 300-1, and a gas inlet 301 is provided in the upper chamber 300-2.

3 is a vertical sectional view of the multi-loop core plasma generator of FIG. 2. Referring to FIG. 3, the multi-loop core plasma generator 320 is composed of a plurality of discharge induction bridges 322 installed across the top of the vacuum chamber 300. The plurality of discharge induction bridges 322 has a tubular structure. The plurality of discharge induction bridges 322 are equipped with multiple loop cores C1, C2, C3. The plurality of discharge induction bridges 322 may be composed of a conductor or a non-conductor. In the case of a conductor, it is preferable to include an insulating region for preventing the eddy current from being generated.

The multiple loop cores C1, C2, and C3 may be configured using a plurality of magnetic cores C1, C2, and C3, each forming an independent loop, as shown in FIG. 4A. Alternatively, as shown in FIG. 4B, a magnetic core C integrated with a plurality of loops may be configured. Primary windings P1, P2, and P3 are wound around the multiple loop cores C1, C2, and C3, respectively. The primary windings P1, P2, and P3 may be wound on only one side or separately separated on both sides with respect to the magnetic core forming one loop.

5 is a diagram illustrating another example of a plasma reactor having a multi-loop core plasma generator, and FIG. 6 is an exploded perspective view illustrating the multi-loop core plasma generator of FIG. 5. 5 and 6, the vacuum chamber 300 of the plasma reactor according to another example includes a lower loop 300-1, an upper chamber 300-2, and a multiple loop core plasma generator 320 therebetween. It is composed. A substrate support 330 and a gas outlet (not shown) are provided in the lower chamber 300-1, and a gas inlet 301 is provided in the upper chamber 300-2.

FIG. 7 is a top cross-sectional view of the multi-loop core plasma generator of FIG. 5. Referring to FIG. 7, the multi-loop core plasma generator 320 includes a plurality of annular magnetic cores C1, C2, C3,... Cn mounted on the plasma generating plate 324 to form a multi-loop core. It consists of primary windings (P1, P2, P3, ..., Pn) wound on it. A plurality of annular magnetic cores C1, C2, C3,... Cn are mounted on the plasma generating plate 324. The plasma generating plate 324 has a plurality of holes 325 formed through the hollow regions of the plurality of annular magnetic cores C1, C2, C3,... Cn. The plurality of holes 325 and the plurality of annular magnetic cores C1, C2, C3,... Cn are formed in the same number so that one annular magnetic core is mounted in each hole. Alternatively, since the number of the holes 325 is greater than the number of the plurality of annular magnetic cores C1, C2, C3,... Cn, there may be empty holes in which the annular magnetic core is not mounted. The plasma generating plate 324 may be composed of a conductor or a non-conductor. In the case of a conductor, it is preferable to include an insulating region for preventing the eddy current from being generated.

8 and 9 show still other examples of a plasma reactor having a multi-loop core plasma generator. First, referring to FIG. 8, in another example of the plasma reactor, a multi-loop core plasma generator 320 is configured above the vacuum chamber 300. The multi-loop core plasma generator 320 is connected to a plurality of C-shaped external discharge bridges 326-1 and 326-2 and external discharge bridges 326-1 and 326-2 mounted on the upper portion of the vacuum chamber 300. It consists of annular magnetic cores (C1, C2) and primary windings (P1, P2) mounted to form a multi-loop core. The external discharge bridges 326-1 and 326-2 may be composed of conductors or non-conductors. In the case of a conductor, it is preferable to include an insulating region for preventing the eddy current from being generated. The gas inlet (not shown) may be configured in the external discharge bridges 326-1 and 326-2 or on the ceiling or sidewall of the vacuum chamber 300. A gas outlet (not shown) is configured at the bottom of the vacuum chamber 300.

Referring to FIG. 9, in another example plasma reactor, a multi-loop core plasma generator 320 is configured above the vacuum chamber 300. In this example, the multi-loop core plasma generator 320 includes a plurality of annular discharge tubes 327-1 and 327-2 constituting the remote plasma generator and annular magnetic cores C1 and C2 mounted thereon. The primary windings P1 and P2 are wound around the annular magnetic cores C1 and C2, respectively. The annular discharge tubes 327-1 and 327-2 may be formed of conductors or non-conductors. In the case of a conductor, it is preferable to include an insulating region for preventing the eddy current from being generated.

As described in the above examples, the multi-loop core plasma generator 320 may have various forms. However, they all have a common multiple loop core (C1, C2, C3, ..., Cn) consisting of a plurality of magnetic cores and primary windings (P1, P2, P3, ..., Pn) . Thus, although not described in this description, any arbitrary plasma reactor consists of multiple loop cores (C1, C2, C3, ..., Cn) and primary windings (P1, P2, P3) consisting of a plurality of magnetic cores. It is well known to those skilled in the art that if the present invention has a Pn), it is suitable as a plasma reactor in which the idea of the present invention can be implemented and can be connected to the current balancing circuit 200 to constitute the plasma reactor of the present invention. You will know.

Meanwhile, referring back to FIG. 1, the substrate support 330 is connected to the bias power supply 340 and biased. For example, two power sources 341 and 342 supplying different radio frequency powers are electrically connected and biased to the substrate support 330 through the impedance matcher 343. The dual bias structure of the substrate support 330 further facilitates plasma generation inside the vacuum chamber 300 and further improves plasma ion energy control on the surface of the substrate W to further improve process productivity. have. Alternatively, the present invention may be modified into a single biased structure by a single power supply. In addition, in the inductively coupled plasma reactor of the present invention, the substrate support 330 may be modified to have a structure having a zero potential without supplying bias power. In the plasma reactor according to the present invention, plasma processing on the substrate W can be performed without supplying a bias in a structure that generates a high-density plasma.

10 to 12 show one embodiment and modifications of the current balancing circuit. First, referring to FIG. 10, the current balancing circuit 200 is composed of a current balance divider 210 having a plurality of transformers 211, 212, 213 of the same capacity connected in series. The plurality of transformers 211, 212, and 213 are configured in the same number as the plurality of plasma generating units G1, G2, and G3, and the primary sides of the plurality of transformers 211, 212, and 213 are grounded and a radio frequency input terminal RFin. ) Is connected in series between the output stages of the impedance matcher 120, and the secondary side is connected to both ends of the plurality of plasma generating units G1, G2, and G3, respectively. The plurality of transformers 211, 212, and 213 equally divide the voltage between the ground and the radio frequency input terminal RFin to divide the divided voltages Vo_1, Vo_2, and Vo_n into the plurality of plasma generation units G1, Output to G2, G3).

Since the currents flowing to the primary sides of the plurality of transformers 211, 212, and 213 are the same, the power supplied to the plurality of plasma generating units G1, G2, and G3 is also the same. When the impedance of any one of the plurality of plasma generation units G1, G2, and G3 is changed to change the amount of current, the plurality of transformers 211, 212, and 213 may interact with each other to achieve a current balance. Thus, the currents supplied to the plurality of plasma generating units G1, G2, G3 are continuously and automatically adjusted uniformly. Although a plurality of transformers 211, 212, and 213 have winding ratios of primary and secondary sides of 1: 1 respectively, this can be changed.

Although not shown in the drawing, the plurality of transformers 211, 212, and 213 may include a protection circuit for preventing a transient voltage from occurring. The protection circuit prevents an increase in the transient voltage of the transformer due to any one of the plurality of transformers 211, 212, and 213 being electrically open. The protection circuit of this function is preferably implemented by connecting a varistor to both ends of each of the plurality of transformers 211, 212 and 213, or using a constant voltage diode such as a Zener diode. Can be implemented.

Referring to FIG. 11, the current balance divider 210a includes a plurality of transformers 211, 212, and 213 and a multi-tap switching circuit 214, 215, and 216. The multi-tap switching circuit 214, 215, 216 includes a switch for controlling the turns ratio by switching between the multi-tap and the multi-tap configured on the secondary side of the plurality of transformers 211, 212, 213. Each switch of the multi-tap switching circuits 214, 215, 216 is electrically connected to one end of the corresponding plasma generating units G1, G2, G3. One end of the secondary side of the plurality of transformers 211, 212, and 213 and one end of the plurality of plasma generating units G1, G2, and G3 are commonly connected.

By controlling the switches of the multi-tap switching circuits 214, 215, and 216, the secondary winding ratios of the plurality of transformers 211, 212, and 213 may be controlled individually or in conjunction with each other. By adjusting the secondary winding ratios of the plurality of transformers 211, 212, and 213 individually or in conjunction with each other, the voltage levels Vo_1, Vo_2, and Vo_n supplied to the plurality of plasma generation units G1, G2, and G3 are individually separated from each other. Can be adjusted differently or in conjunction. Therefore, the density and ion energy of the plasma generated by the plurality of plasma generating units G1, G2, and G3 can be partially controlled as necessary.

Referring to FIG. 12, another variation of the current balance divider 210b includes a plurality of transformers 211, 212, 213 and a multi-tap switching circuit 217, 218, 219. The multi-tap switching circuits 217, 218, and 219 are configured on the secondary side of the plurality of transformers 211, 212, and 213, respectively, between the middle tap connected to the ground, the multi tap consisting of both sides of the middle tap, and the multi taps on both sides. It consists of two switches that adjust the turns ratio by switching operation. One of the two switches is electrically connected to one end of the corresponding plasma generation unit G1, G2, G3, and the other switch is connected to the other end.

In the current balancing circuit 200b, the secondary side of the plurality of transformers 207, 208, and 209 transfers the constant voltages (Vop_1, Vop_2, and Vop_n) to the lower switch based on the middle tap connected to the ground, respectively. Through the negative voltage (Von_1, Von_2, Von_n) is output through. The voltage levels of the constant voltages (Vop_1, Vop_2, Vop_n) and the negative voltages (Von_1, Von_2, Von_n) output from the secondary side of each transformer (211, 212, 213) are switched by the multi-tap switching circuit (217, 218, 219). It is controlled according to the operation.

13 and 14 show other embodiments and modifications of the current balancing circuit. Referring to FIG. 13, the current balancing circuit 200 of another embodiment includes a current variable 227 and a current balance divider 220. The current variable unit 227 may be configured as a variable inductor, and one end of the variable inductor has a plurality of plasma generating units G1, G2, and G3 at the other end of the RF inlet (RFin) (the output end of the impedance matcher 120). ) Are commonly connected. In the current balance divider 220, a plurality of induction coils 221, 222, and 223 and a plurality of induction coils 221, 222, and 223 respectively connected to the plurality of plasma generating units G1, G2, and G3 are wound in common. Consisting of a magnetic core 214. The plurality of induction coils 221, 222, and 223 are connected in one-to-one correspondence with the plurality of plasma generating units G1, G2, and G3, and the other end is grounded. The plurality of induction coils 221, 222, and 223 basically have the same number of turns. However, it is also possible to vary the number of turns depending on the structural characteristics of the plasma reactor.

The current variable 227 controls the total amount of current supplied to the plurality of plasma generating units G1, G2, G3. The current balance divider 220 is automatically controlled to balance the amount of current input to each plasma generating unit G1, G2, G3 by the interaction of the plurality of induction coils 221, 222, 223.

The current balance divider 220 may include a multi-tap switching circuit 224, 225, 226 including a power strip and a switch configured in each of the plurality of induction coils 221, 222, and 223. The turns ratios of the plurality of induction coils 221, 222, and 223 may be individually or globally changed using the multi-tap switching circuits 224, 225, and 226. Current variable 227 may be configured between ground and current balance divider 220, as shown in FIG. 14. As shown in FIG. 15, the current variable 227a may be configured as a variable capacitor.

16 is a circuit diagram showing another embodiment of the current balancing circuit. Referring to the drawings, another variation of the current balancing circuit 200 is composed of a power transformer 240 and a current balancing divider 210. The power transformer 240 has a primary side connected to a radio frequency input terminal RFin, receives a radio frequency, and outputs a constant voltage V_p and a negative voltage V_n at the secondary side. The current balance divider 210 receives the constant voltage V_p and divides the voltage into a plurality of voltages, and applies the divided voltages Vo_1, Vo_2, and Vo_n to one end of the plurality of plasma generation units G1, G2, and G3, respectively. do. The negative voltage V_n of the power transformer 240 is commonly applied to the other ends of the plurality of plasma generating units G1, G2, and G3. In this case, the current balance divider 210 automatically adjusts and distributes the amount of current so that the current values input to the plurality of plasma generating units G1, G2, and G3 are balanced with each other.

17 is a detailed circuit diagram of the current balancing circuit of FIG. 16. Referring to the figure, one end of the power transformer 240 is connected to a radio frequency input (RFin), the other end is connected to ground. The secondary side of power transformer 240 has an intermediate tab 241 electrically connected to ground. Therefore, one end of the secondary side outputs the constant voltage V_p and the other end outputs the negative voltage V_n. The ratio of the constant voltage V_p and the negative voltage V_n is determined according to the position of the intermediate tap 241. For example, the intermediate tap 241 may be configured such that the ratio of the constant voltage V_p and the negative voltage V_n is 1: 2. In this case, the current balance divider 210 includes a plurality of plasma generating units G1, The current balance is performed in a power capacity range of about one third of the total power capacity for driving G2 and G3).

As described above with reference to FIG. 10, the current balance divider 210 includes a plurality of transformers 211, 212, and 213 respectively corresponding to the plurality of plasma generating units G1, G2, and G3. Although a plurality of transformers 211, 212, and 213 have winding ratios of primary and secondary sides of 1: 1 respectively, this can be changed. Each primary side of the plurality of transformers 211, 212, 213 is connected in series between one end of the secondary side of the power transformer 240 and ground, and one end of each secondary side has a plurality of plasma generating units G1, G2, G3. Are connected to each other and the other end is connected to ground.

The current balance divider 220 equally divides the constant voltage V_p by the plurality of transformers 211, 212, and 213, and divides the divided voltages Vo_1, Vo_2, and Vo_n into a plurality of plasma generation units G1, G2, G3). When the primary sides of the plurality of transformers 211, 212, and 213 are connected in series and the impedance of any one of the plurality of plasma generating units G1, G2, and G3 is changed to change the amount of current, the plurality of transformers 211 is generated. , 212, 213 interact as a whole to automatically balance the current. As described above, the plurality of transformers 211, 212, and 213 may include a protection circuit for preventing a transient voltage from occurring.

18 is a view showing a modification of the current balance divider of FIG. Referring to the drawings, the current balance divider 210c according to the modification further includes a multi-tap switching circuit 217, 218, 219 on the secondary side of the plurality of transformers 211, 212, 213. The multi-tap switching circuits 217, 218, and 219 are configured of a switch connected to a second side of the plurality of transformers 211, 212, and 213 and one of the power strips to a ground.

The divided voltages Vo_1, Vo_2, and Vo_n induced and output to the secondary side of the plurality of transformers 211, 212, and 213 are adjusted to different voltage levels according to the switching states of the multi-tap switching circuits 217, 218, and 219. . Accordingly, the power delivered to the plurality of plasma generating units G1, G2, G3 may be adjusted to be low or high as a whole, and may be adjusted to be low or high in part.

19A through 19C are circuit diagrams illustrating modifications of a power transformer.

First, referring to FIG. 19A, the secondary side of the power transformer 240a according to one modification is composed of two separate windings 222-1 and 222-2. One of the two windings 242 and 243 outputs a constant voltage V_p to one end and the other end is connected to ground, and the other winding 243 is connected to the other end and connected to the other end. Output the voltage V_n.

Referring to FIG. 19B, a power transformer 240b according to another modification includes a multi-tap switching circuit 245 on the secondary side. In the multi-tap switching circuit 245, the power transformer 240b is configured as a switch for connecting one of the multi-tap and the multi-tap configured on the secondary side to ground. In the power transformer 240b, the ratio of the constant voltage V_p and the negative voltage V_n varies according to the switching state of the multi-tap switching circuit 245.

Referring to FIG. 19C, a power transformer 240c according to another modified example includes first and second multi-tap switching circuits 246 and 247 configured on both sides of the secondary side with respect to the intermediate tap 241. The first multi-tap switching circuit 246 outputs a constant voltage Vp that varies according to the switching state, and the second multi-tap switching circuit 247 also outputs a negative voltage Vn that varies according to the switching state. Accordingly, the ratio of the constant voltage V_p and the negative voltage V_n and the respective voltage levels vary according to the switching of the first and second multi-tap switching circuits 245 and 246.

20 is a circuit diagram showing another modified example of the current balancing circuit. Referring to the drawings, another variation of the current balancing circuit 200d includes a power transformer 240d and a current balancing divider 210d. The primary side of the power transformer 240d has one end connected to a radio frequency input terminal RFin and the other end connected to ground. Secondary side 22 of power transformer 240d has an intermediate tab 241 electrically connected to ground. Therefore, one end of the secondary side 22 outputs the constant voltage V_p, and the other end outputs the negative voltage V_n. In addition, a multi-tap switching circuit 248 including a switch connected to any one of the multi-tap and the multi-tap configured between the intermediate tap 241 and the constant voltage output terminal is provided.

The plurality of transformers 211, 212, 213 of the current balance divider 210d are connected in series between a primary voltage output terminal of the power transformer 240 and a switch of the multi-tap switching circuit 248 on each primary side. One end of each secondary side of the plurality of transformers 211, 212, 213 is connected to one end of a corresponding plurality of plasma generating units G1, G2, G3, and the other end of each secondary side of the multi-tap switching circuit 248. Connected to the switch.

In the current balance divider 210d configured as described above, the voltage level applied to the primary sides of the plurality of transformers 211, 212, and 213 is basically higher than the ground voltage level and varies according to the switching state of the multi-tap switching circuit 248. Thus, the current balance divider 210d allows the current balance adjustment to be made within a minimum power range that can cover the current imbalance of the plurality of plasma generating units G1, G2, G3. The multi-tap switching circuit 248 may be replaced with a fixed tap.

21 is a block diagram showing a control circuit configuration for controlling a current balancing circuit. Referring to the drawings, the current balancing circuit 200 is controlled by the controller 350. The controller 350 may be configured as a computer system including a central processing unit, a memory device, and a control program. The controller 350 controls the current balancing circuit 200 according to the user control, the process condition data, and the plasma state value detected by the plasma state monitoring circuit 352. The plasma state monitoring circuit 352 detects the plasma state using one or more sensors 354 for detecting the plasma state.

For example, referring to FIG. 11, the controller 350 controls the switching states of the multi-tap switching circuits 214, 215, and 216 provided in the current balance divider 210a to control a plurality of plasma generating units G1, G2, and the like. The power supplied to G3) can be controlled variably. 12, the power supplied to the plurality of plasma generation units G1, G2, and G3 is variably controlled by controlling the switching states of the multi-tap switching circuits 217, 218, and 219 included in the current balance divider 210b. Can be controlled.

13 and 14, the controller 350 controls the multi-tap switching circuits 224, 225, and 227 and the current variable 227 of the current balance divider 220 to independently control each other to generate a plurality of plasmas. The power supplied to the units G1, G2, G3 can be controlled in whole or in part.

Referring to FIG. 18, the controller 350 may control the multi-tap switching circuits 217, 218, and 219 of the current balance divider 210c to variably control the power supply to the plurality of plasma generating units G1, G2, and G3. Can be. Referring to FIGS. 19B, 19C, and 20, the controller 350 controls a plurality of power strip switching circuits 245, 246, 247, and 248 provided in the power transformers 240b, 240c, and 240d. The power supplied to the plasma generating units G1, G2, and G3 can be controlled to be changed as a whole.

In addition, even when the power transformer 240 and the current balance divider 210 are each provided with a multi-tap switching circuit, the control unit 350 controls each of the multi-tap switching circuits to control the plurality of plasma generating units G1, G2, and G3. The power supplied to the controller can be controlled in whole or in part.

The above-described multi-tap switching circuits configured in the current balance circuit configured in the inductively coupled plasma reactor of the present invention may be configured as mechanical multi-tap switches, but are preferably semiconductor switch elements (eg, field effect transistors). Etc.).

The plasma reactor with a multi-loop core plasma generator according to the present invention can be variously modified and can take various forms. It is to be understood, however, that the present invention is not limited to the specific forms referred to in the above description, but rather includes all modifications, equivalents and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood to do.

According to the plasma reactor with a multi-loop core plasma generator of the present invention as described above, in the plasma reactor with a multi-loop core plasma generator including a multi-loop core and the primary winding is supplied to the primary winding of the multi-loop core By adjusting the current balance, a large area uniform high density plasma can be obtained.

Claims (18)

A multi loop core plasma generator comprising a multi loop core and primary windings; A power supply for supplying current to the primary windings; A current balancing circuit which distributes and distributes the current supplied from the power supply to the primary windings of the multiple loop core; A substrate support on which a substrate to be processed to be processed by the plasma gas generated by the multi-loop core plasma generator is placed; And And a bias power supply for supplying bias power to the substrate support. The method of claim 1, The current balancing circuit includes a current balance divider having a plurality of transformers, each corresponding to a multiple loop core, The plurality of transformers are connected in series between a radio frequency input terminal whose primary side is connected to a power source and ground, and the secondary side is connected to a primary winding of a corresponding multi-loop core; Divide the voltage between the radio frequency input and ground; A plasma reactor for supplying a plurality of divided voltages to the primary winding of the corresponding multiple loop core. The method of claim 2, Wherein said current balance divider comprises variable means for varying the turns ratio on the secondary side of the plurality of transformers. The method of claim 3, Wherein the current balance distributor comprises an intermediate tap configured on a secondary side of the plurality of transformers and connected to ground. The method of claim 1, The current balancing circuit includes a current varyer for variably controlling the current supplied to the primary windings of the multiple loop core; And a current balance divider for balancing each current supplied to the primary windings of the multiple loop core, The current balance divider includes a plurality of induction coils connected to the primary windings of the multiple loop core; And a magnetic core to which a plurality of induction coils are commonly wound. The method of claim 5, And plasma variable means for varying the number of turns of the plurality of induction coils. The method of claim 1, The current balancing circuit includes a power transformer connected to a power supply; And The secondary voltage of the power transformer is applied and divided into a plurality of voltages, and the divided voltages are respectively applied to one end of the primary windings of the multiple loop core, and the current values inputted to the primary windings of each multiple loop core are balanced with each other. And a current balance distributor for distributing the amount of current to achieve. The method of claim 7, wherein The power transformer has a middle tap grounded on a secondary side and outputs a constant voltage V_p and a negative voltage V_n; The current balancing circuit receives the constant voltage of the power transformer and divides it into a plurality of voltages and inputs them to one end of the primary windings of the multiple loop core; The negative voltage of the power transformer is commonly applied to the other end of the primary windings of the multiple loop core. The method of claim 7, wherein The current balance divider includes a plurality of transformers respectively corresponding to the primary windings of the multi-loop core, The plurality of transformers have a primary side connected in series between the secondary side of the power transformer and ground, and the secondary side connected to primary windings of the corresponding multi-loop core; Divide the voltage between the secondary side of the power transformer and ground; A plasma reactor for supplying a plurality of divided voltages to the primary windings of the corresponding multiple loop cores, respectively. The method of claim 9, Wherein said current balance divider comprises variable means for varying the turns ratio on the secondary side of the plurality of transformers. The method of claim 8, And variable means for varying the ratio of the constant voltage and the negative voltage of the power transformer. The method of claim 8, And variable means for varying the ratio of the constant voltage and the negative voltage of the power transformer and respective voltage levels. The method of claim 7, wherein The power transformer is configured on the secondary side and grounded intermediate tap; A multi-tap switching circuit having a switch operable to switch any one of the multi-tap and the multi-tap configured between the intermediate tap and the constant voltage output stage to a current balance divider, And the current balance divider divides the voltage between the constant voltage output of the power transformer and the switch of the multi-tap switching circuit and applies each to one end of the primary windings of the multi-loop core. The method according to any one of claims 2 to 13, The current balance divider includes a protection circuit for preventing a transient voltage is generated. The method according to any one of claims 2 to 13, And a control unit for controlling the current balancing circuit to variably control the power supplied to the primary windings of the multi-loop core. The method of claim 15, And the control unit controls the current balancing circuit based on at least one of a user control input, process condition data, and a plasma state detection value provided from a plasma state monitoring circuit for detecting a plasma state. The method of claim 1, Wherein said bias power source has a bias structure of either a single bias or a double bias. delete

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