KR20150064722A - Plasma impedance matching system and the methode - Google Patents

Abstract

The present invention relates to an apparatus and method for matching an impedance of a plasma in a process apparatus using plasma of a semiconductor manufacturing facility, and more particularly to an apparatus and method for matching impedance of a plasma, Matches the impedance between the power supply and the process chamber.

Description

[0001] PLASMA IMPEDANCE MATCHING SYSTEM AND THE METHODE [0002]

The present invention relates to a plasma impedance matching apparatus and method, and more particularly, to an apparatus and method for matching an impedance of a plasma in a process apparatus using plasma of a semiconductor manufacturing facility.

A plasma impedance matching device using high frequency power is an important impedance device for generating and maintaining a plasma as an impedance matching device for maximizing the power of a high frequency power source in a plasma processing chamber.

When transmitting power to a process chamber for generating a plasma in a high frequency power supply device, impedance of the power supply device and plasma must be equal to each other in order to transmit maximum power without reflected waves. Impedance matching is performed by adjusting the impedance to have such an electrical characteristic do.

If the plasma impedance is not matched to the impedance of the power of the high frequency power source, a certain power can not be transmitted, so that the plasma density There is a problem that the deviation of the process result increases. Thus, impedance matching must be considered to deliver high frequency power constantly into the process chamber, and an impedance matching device is provided between the high frequency power source and the plasma generator in the process chamber.

Generally, the impedance matching device is composed of a variable capacitor and an inductor. By adjusting the variable capacitor, the impedance matching is realized so that the impedance of the RF power source is equal to the impedance of the process chamber.

A variable capacitor of a general impedance matching device changes the impedance of the high frequency power source by changing the capacitance by adjusting the interval of the capacitors by using the driving means combined with the stepping motor and the gear stage.

However, since the capacitor is adjusted by the mechanical driving means, the time delay becomes longer by the operation time of the driving means and it is difficult to precisely control. Especially, when the high frequency power supplies power in the pulse mode, Fast impedance matching is difficult.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasma impedance matching apparatus and a method thereof that enable more accurate and quick matching in plasma impedance matching.

The present invention is not limited to the above-described problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above-mentioned object, an apparatus for matching a plasma impedance according to an embodiment of the present invention includes an impedance matcher connected to a high-frequency power transmission path to match a plasma impedance, and a controller for sending a control signal to the impedance matcher The impedance matcher includes a first variable capacitor for receiving a control signal of the controller and adjusting a capacitance by a mechanical driving unit, a switch connected to a plurality of capacitors, and on / off of the switch according to a control signal of the control unit, And a second variable capacitor that electrically adjusts the voltage of the second variable capacitor.

The first variable capacitor and the second variable capacitor are connected in parallel to each other.

The plurality of capacitors of the second variable capacitor are connected in parallel to each other.

The plurality of capacitors of the second variable capacitor all have the same capacitance.

In addition, some of the plurality of capacitors of the second variable capacitor have different capacitances.

The switch may be a pin diode.

Further, the high frequency power supply supplies power in a pulse mode.

According to an aspect of the present invention, there is provided a plasma processing apparatus for processing plasma in a plasma processing apparatus, comprising: a processing chamber; an electrode for generating a plasma from a gas supplied into the processing chamber; and a high- And an impedance matcher connected to the high frequency transmission line to match the impedance of the high frequency power and a controller for transmitting a control signal to the impedance matcher, wherein the impedance matcher is connected to the high frequency transmission line, A plurality of capacitors are connected to the high frequency transmission line, and a switch is connected to each of the capacitors, and the switch is electrically turned on / off according to a control signal of the controller. By doing so, In that it comprises a second variable capacitor for adjusting the capacitance during characterized.

The first variable capacitor and the second variable capacitor are connected in parallel to each other.

The electrode is formed of two electrode flat plates parallel to each other in the process chamber.

According to another aspect of the present invention, there is provided a method of matching a plasma impedance of a semiconductor fabrication facility, comprising: generating a plasma in a process chamber by supplying a high frequency power; measuring an impedance of the plasma; Determining a capacitance adjustment value corresponding to the capacitance adjustment value and determining whether the variable capacitor operates according to the capacitance adjustment value to match the impedance, wherein the step of determining whether to operate the variable capacitor and matching the impedance includes: Determining whether or not the first variable capacitor that controls the capacitance by the means is operated, and determining whether the second variable capacitor that controls the capacitance is operated by electrically interrupting the switch connected to each of the capacitors constituted by the plurality of capacitors Ha Characterized in that it comprises the steps:

The determining whether the second variable capacitor operates may further include selecting a capacitor to be switched among the plurality of capacitors.

In addition, the first variable capacitor coarsely adjusts the capacitance adjustment value, and the second variable capacitor finely adjusts the capacitance adjustment value.

Further, the high frequency power supply supplies power in a pulse mode.

The plurality of capacitors may have the same capacitance.

The plurality of capacitors are connected in parallel with each other.

The first variable capacitor and the second variable capacitor are connected in parallel to each other.

According to an aspect of the present invention, there is provided a method of impedance matching in a plasma processing apparatus, comprising: a first variable capacitor capable of mechanically adjusting a capacitance;

There is provided a second variable capacitor for connecting a switch to a capacitor to electrically adjust a capacitance by electrically turning on / off a switch, wherein the capacitance of one or both of the first variable capacitor and the second variable capacitor is adjusted to match the impedance .

The first variable capacitor and the second variable capacitor are connected in parallel to each other.

In addition, a plurality of capacitors of the second variable capacitor are provided.

The plurality of capacitors of the second variable capacitor are connected in parallel to each other.

The plurality of capacitors may have the same capacitance.

According to the present invention, since the plasma impedance matching is effectively performed, the reflection power can be minimized.

According to the present invention, it is possible to minimize process defects of the substrate by minimizing the reflected power.

FIG. 1 is a configuration diagram of a plasma impedance matching apparatus according to an embodiment of the present invention. Referring to FIG.
FIG. 2 is a block diagram illustrating a plasma impedance matching apparatus according to another embodiment of the present invention. Referring to FIG.
3 is a block diagram of a plasma substrate processing apparatus to which a plasma impedance matching apparatus according to an embodiment of the present invention is coupled.
4 is a block diagram of a plasma substrate processing apparatus to which a plasma impedance matching apparatus according to another embodiment of the present invention is coupled.
5 is a block diagram of a plasma substrate processing apparatus to which a plasma impedance matching apparatus according to another embodiment of the present invention is coupled.
6 is a flowchart illustrating a plasma impedance matching method according to an embodiment of the present invention.
7 is a flowchart illustrating a plasma impedance matching method according to another embodiment of the present invention.
8 is a flowchart illustrating a plasma impedance matching method according to another embodiment of the present invention.
9 is a waveform diagram showing plasma state change according to the present invention when high-frequency power in a pulse mode is supplied.

The embodiments of the present invention can be modified into various forms and the scope of the present invention should not be interpreted as being limited by the embodiments described below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Accordingly, the shapes of the components and the like in the drawings are exaggerated in order to emphasize a clearer description.

FIG. 1 is a configuration diagram of a plasma impedance matching apparatus according to an embodiment of the present invention. Referring to FIG.

FIG. 2 is a block diagram illustrating a plasma impedance matching apparatus according to another embodiment of the present invention. Referring to FIG.

Referring to FIGS. 1 and 2, a plasma impedance matching apparatus 2200 is disposed between a high frequency power supply 2110 for supplying high frequency power and a process chamber 2160 for plasma processing the substrate.

The plasma impedance matching apparatus 2200 of the present invention includes an impedance matcher 2210 and a controller 2250.

The impedance matcher 2210 uses a variable capacitor to match the impedance between the high frequency power source 2110 and the process chamber 2160.

The impedance matcher 2210 is connected to the high frequency transmission line 2120 and the capacitance is changed according to a control signal sent from the controller 2250. The impedance matcher 2210 includes a first variable capacitor 2220 and a second variable capacitor 2240.

The first variable capacitor 2220 includes a capacitor 2221 and a driving means 2223.

The first variable capacitor 2220 adjusts the capacitance of the capacitor 2221 by the driving means 2223. The driving means 2223 is a mechanical driving means such as a combination of a stepping motor and a gear stage. The motor rotates in accordance with the transmitted control signal, and the gear stage rotated by the motor adjusts the interval of the capacitor.

The second variable capacitor 2240 includes a capacitor 2241 and a switch 2243.

A plurality of capacitors 2241 are provided and a switch 2243 is connected to each of the capacitors 2241. The second variable capacitor 2240 controls the capacitance by turning on / off the switch 2243 connected to each of the plurality of capacitors 2241.

The switch 2243 is electrically turned on / off according to the control signal and the capacitor 2241 whose switch 2243 is turned on receives power from the high frequency transmission line 2120. The switch 2243 may have various forms that operate electrically, and a pin diode may be used.

A plurality of capacitors 2241 are connected to the high-frequency transmission line 2120. The switch 2243 adjusts the capacitance of the second variable capacitor 2240 by a combination of the capacitances of the capacitors 2241 that are turned on. The plurality of capacitors 2241 may be connected in parallel with each other. The capacitance of the second variable capacitor 2240 can be obtained by simply summing the capacitance of the capacitor 2241 on the switch 2243 among the plurality of capacitors 2241 connected in parallel.

The capacitances of the plurality of capacitors 2241 may all have the same capacitance. Alternatively, some or all of the plurality of capacitors 2241 may have different capacitances from each other. Therefore, the capacitance of the second variable capacitor 2240 can be finely adjusted by combining the capacitances of the plurality of capacitors 2241.

The first variable capacitor 2220 and the second variable capacitor 2240 may be connected in parallel with each other. The first variable capacitor 2220 may be connected in parallel and the second variable capacitor 2240 may be connected in parallel to the high frequency transmission line 2120 that transmits the high frequency power from the high frequency power source 2110 to the process chamber 2160.

The second variable capacitor 2240 may operate dependent on the first variable capacitor 2220 in accordance with the control signal. The first variable capacitor 2220 adjusts the capacitance by the mechanical driving means 2223 according to the capacitance adjustment value required to adjust the impedance of the high frequency power source 2110 and then the capacitance of the second variable capacitor 2240 The remaining capacitances can be fine-tuned. The capacitance of the second variable capacitor 2240 which is turned on by the electrical signal by the first variable capacitor 2220, which is controlled by the mechanical driving means 2223, The capacitances of the plurality of capacitors 2241 can be combined and precisely controlled.

The first variable capacitor 2220 may be used when the power of the high frequency power source 2110 varies in a large range, and the second variable capacitor 2240 may be used when the power of the high frequency power source 2110 is varied within a small range. For example, the first variable capacitor 2220 can be used and fine tuned to the second variable capacitor 2240 when the state of the supplied process gas varies greatly, such as when the process first starts.

The controller 2250 receives the measured value of the impedance in the process chamber 2160 or the measured value of the reflected power on the high frequency transmission line 2120 input to the RF power supply 2110 and provides impedance matching to the impedance matcher 2210 And a capacitance adjustment value for the first time.

The controller 2250 sends the drive control signal of the mechanical drive means 2223 of the first variable capacitor 2220 in response to the capacitance adjustment value and controls the on / off control of the switch 2243 of the second variable capacitor 2240 Signal. In particular, the controller 2250 transmits a control signal for selecting the capacitor 2241 to be switched among the plurality of capacitors 2241 of the second variable capacitor 2240 according to the capacitance adjustment value. A capacitor to be connected to the high frequency transmission line 2120 among the plurality of capacitors 2241 of the second variable capacitor 2240 is selected according to the capacitance adjustment value and the switch 2243 of the selected capacitor 2241 is turned on So that the control signal is transmitted to the switch.

The controller 2250 receives the measured value from the impedance meter 2140 and / or the reflected power meter 2150 and determines a capacitance adjustment value for impedance adjustment between the RF power supply 2110 and the process chamber 2160.

Impedance meter 2140 measures the plasma impedance in process chamber 2160 and applies an impedance measurement to controller 2250.

The reflection power meter 2150 measures reflected power coming into the RF power supply 2110 and applies a reflected power measurement value to the controller 2250.

3 is a block diagram of a plasma substrate processing apparatus to which a plasma impedance matching apparatus according to an embodiment of the present invention is coupled.

4 is a block diagram of a plasma substrate processing apparatus to which a plasma impedance matching apparatus according to another embodiment of the present invention is coupled.

5 is a block diagram of a plasma substrate processing apparatus to which a plasma impedance matching apparatus according to another embodiment of the present invention is coupled.

3 to 5, a plasma substrate processing apparatus 2000 coupled to the plasma impedance matching apparatus 2220 of the present invention includes a process chamber 2160, an electrode 2170, a high frequency power source 2110, (2220), and a controller (2250).

The plasma substrate processing apparatus 2000 is a device for processing a substrate by changing a gas into a plasma state in the process chamber 2160 and using the same.

The process chamber 2160 performs processing of the substrate using plasma, and the electrode 2170 supplies electric energy such that gas introduced into the process chamber 2160 is ionized and changed into a plasma state. Electrodes 2170 may be capacitively coupled plasma (CCP), consisting of two electrode plates parallel to process chamber 2160, or inductively coupled plasma (ICP) Plasma).

Referring to Figures 3 and 4, a capacitively coupled plasma source transfers electric energy to the electrons of the gas introduced into the process chamber 2160 using a charge field. The capacitive coupled plasma source has a form in which a high frequency power source is connected to two electrode flat plates or a high frequency power source is connected only to an upper electrode flat plate among the two electrode flat plates.

Referring to FIG. 5, an inductively coupled plasma source utilizes an induction field to transfer electrical energy to electrons in the gas entering the process chamber 2160. The inductively coupled plasma source is separately coupled to a plasma generator above the process chamber 2160 to convert the introduced gas into a plasma state and to provide the plasma to the process chamber 100 in a downstream stream manner.

The RF power supply 2110 supplies RF power to the electrodes in the process chamber 2160 through the RF transmission line 2120 to change the electrons of the gas supplied into the process chamber 2160 into a plasma state. The RF power supply 2110 can supply power in a pulse mode.

As described above, the plasma impedance matching apparatus 2200 according to the present invention includes an impedance matcher 2210 and a controller 2250. The description of the impedance matcher 2210 and the controller 2250 is the same as that described above .

6 is a flowchart illustrating a plasma impedance matching method according to an embodiment of the present invention.

7 is a flowchart illustrating a plasma impedance matching method according to another embodiment of the present invention.

8 is a flowchart illustrating a plasma impedance matching method according to another embodiment of the present invention.

6 to 8, the operation of one embodiment of the plasma impedance matching apparatus of the present invention will be described in detail.

The high frequency power source 2110 supplies the high frequency power to the electrode 2170 through the high frequency transmission line 2120. At this time, the gas introduced into the process chamber 2160 receives the electric energy and changes to the plasma state (S2100). The process chamber 2160 into which the plasma is introduced performs the substrate processing process using the plasma. Impedance meter 2140 measures the plasma impedance in process chamber 2160 and applies it to controller 2250 and the controller determines a capacitance adjustment value in accordance with the received plasma impedance measurement value (S2200). At this time, it is determined whether the variable capacitor of the impedance matcher 2210 is operated according to the capacitance adjustment value (S2300). If it is necessary to operate the variable capacitor, it is determined whether the first variable capacitor 2220 is operated and / or the second variable capacitor 2240 is operated (S2310, S2330). When the operation of the first variable capacitor 2220 is required, the controller 2250 sends an operation control signal to the mechanical driving means 2223 in response to the capacitance adjustment value (S2312). When the operation of the second variable capacitor 2240 is required, the controller 2250 sends an operation control signal to the switch 2243 of each of the plurality of capacitors 2241 in response to the capacitance adjustment value (S2332).

Referring to FIG. 7, in the case of the second variable capacitor 2240 including a plurality of capacitors 2241, the second variable capacitor 2240 is selected and a capacitor to be switched is selected according to the capacitance adjustment value (S2334) ). That is, the second variable capacitor 2240, which turns on / off the switch 2243 and connects the capacitor 2241 to the high-frequency transmission line 2120, is turned on and off to meet the capacitance adjustment value by the capacitance combination of the switched capacitor 2241 . The controller 2250 sends an operation control signal to the switch 2243 of the selected capacitor 2241 (S2336).

  Referring to FIG. 8, as described above, the first variable capacitor 2220 and the second variable capacitor 2240 can be controlled in a main-type relationship. After determining whether the variable capacitor is operated (S2300), it is determined whether or not the first variable capacitor 2220 is operated (S2310). Then, in accordance with the capacitance adjusted by the first variable capacitor 2220, (S2320). The second variable capacitor 2240 may slightly adjust the second variable capacitor 2240 in response to the capacitance adjustment value after the first variable capacitor 2220 has adjusted the coarse adjustment to meet the capacitance adjustment value necessary for the plasma impedance matching .

 When the plasma impedance in the process chamber 2160 and the impedance of the RF power supply 2110 are not matched, the first variable capacitor 2220 and the second variable capacitor 2240 of the plasma impedance matching device 2200 are used Thereby matching the plasma impedance.

9 is a waveform diagram showing plasma state change according to the present invention when high-frequency power in a pulse mode is supplied.

Referring to FIG. 9, the plasma impedance matching apparatus 2200 of the present invention adjusts the impedance so as to optimize the plasma impedance so as to correspond to the pulse high-frequency power supplied when the high-frequency power is supplied from the high-frequency power source 2110 in the pulse mode.

In an embodiment of the present invention, the second variable capacitor 2240 is provided as a plurality of capacitors 2241. However, without being limited to this, the second variable capacitor 2240 may be provided with one capacitor 2241.

In an embodiment of the present invention, the first variable capacitor 2220 and the second variable capacitor 2240 are connected in parallel with each other. Therefore, it is easy to calculate the capacitance of the first and second variable capacitors 2220 and 2240. However, the first variable capacitor 2220 and the second variable capacitor 2240 can be connected in series without limitation.

In an embodiment of the present invention, a plurality of capacitors 2241 of the second variable capacitor 2240 are connected in parallel with each other. Therefore, it is easy to calculate the capacitance of the second variable capacitor 2240. However, without being limited thereto, the plurality of capacitors 2241 of the second variable capacitor 2240 may be connected in series with each other.

In an embodiment of the present invention, the high frequency power source 2110 supplies power in a pulse mode. However, the present invention is not limited to this, and the high-frequency power supply 2110 can supply power at a continuous frequency.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

2000 Plasma substrate processing equipment
2110 High frequency power source 2120 High frequency transmission line
2140 Impedance Meter 2150 Reflective Meter
2160 process chamber 2170 electrode
2180 Inductors
2200 Plasma impedance matching device
2210 Impedance Matcher
2220 first variable capacitor
2221 Capacitor 2223 Mechanical drive means
2240 second variable capacitor
2241 Capacitors 2243 Switches
2250 controller

Claims (15)

An impedance matcher connected to the transmission path of the high frequency power to match the plasma impedance; And
And a controller for transmitting a control signal to the impedance matcher,
The impedance matcher includes:
A first variable capacitor which receives a control signal of the controller and adjusts a capacitance by a mechanical driving means; And
And a second variable capacitor electrically connecting the switch to the plurality of capacitors and electrically controlling the capacitance by turning on / off the switch according to the control signal of the controller. The method according to claim 1,
Wherein the first variable capacitor and the second variable capacitor are connected in parallel to each other. The method according to claim 1,
And the plurality of capacitors of the second variable capacitor are connected in parallel with each other. 4. The method according to any one of claims 1 to 3,
Wherein the plurality of capacitors of the second variable capacitor all have the same capacitance. 4. The method according to any one of claims 1 to 3,
Wherein some of the plurality of capacitors of the second variable capacitor have different capacitances from each other. 4. The method according to any one of claims 1 to 3,
Wherein the switch comprises a pin diode. 4. The method according to any one of claims 1 to 3,
Wherein the high frequency power source supplies power in a pulse mode. A process chamber;
An electrode for generating a plasma from the gas supplied into the process chamber;
A high frequency power source for outputting high frequency power to the electrode through a high frequency transmission line;
An impedance matcher connected to the high frequency transmission line to match the impedance of the high frequency power;
And a controller for transmitting a control signal to the impedance matcher,
The impedance matcher
A first variable capacitor connected to the high frequency transmission line for adjusting a capacitance by a mechanical driving means according to a control signal of the controller; And
And a second variable capacitor connecting a plurality of capacitors to the high-frequency transmission line, connecting a switch to each of the capacitors, and electrically controlling on / off the switch according to a control signal of the controller to adjust the capacitance To the plasma processing apparatus. 9. The method of claim 8,
Wherein the first variable capacitor and the second variable capacitor are connected in parallel to each other. 10. The method according to claim 8 or 9,
Wherein the electrode comprises two electrode flat plates parallel to each other in the process chamber. A method of matching an impedance of a plasma processing apparatus,
A first variable capacitor capable of mechanically adjusting a capacitance;
There is provided a second variable capacitor for connecting a switch to a capacitor to electrically adjust a capacitance by electrically turning on / off the switch,
And adjusting the capacitance of one or both of the first variable capacitor and the second variable capacitor to match the impedances. 12. The method of claim 11,
Wherein the first variable capacitor and the second variable capacitor are connected in parallel to each other. 13. The method of claim 12,
Wherein a plurality of capacitors of the second variable capacitor are provided. 14. The method of claim 13,
Wherein a plurality of capacitors of the second variable capacitor are connected in parallel to each other. The method according to claim 13 or 14,
Wherein the capacitors of the plurality of capacitors have the same capacitance.

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