KR20160129300A - Antenna for inductively coupled plasma generation apparatus and method of control thereof and inductively coupled plasma generation apparatus comprising the same - Google Patents

Abstract

The present invention relates to an antenna for an inductively coupled plasma generating device for forming uniform plasma to be suitable for processing a large object to be processed. The antenna comprises at least one coil piece of a circular arc shape wherein the coil piece comprises: a vertical portion; and a slope portion inclined to the vertical portion to have a larger surface with respect to a horizontal surface vertical to the vertical portion from a central portion to an outer portion around the antenna.

Description

TECHNICAL FIELD [0001] The present invention relates to an antenna for an inductively coupled plasma generator, a control method therefor, and an inductively coupled plasma generating device including the same. [0002] In an inductively coupled plasma generator,

More particularly, the present invention relates to an antenna for an inductively coupled plasma generator, a control method thereof, and an inductively coupled plasma generator including the same.

Plasma refers to the fourth state of a substance other than solid, liquid, and gas. It is a highly ionized gas containing cations, electrons and free radicals, atoms and molecules, And is widely used in various industrial fields and is typically used mainly in semiconductor manufacturing processes such as etching, deposition, cleaning, ashing, and the like.

Examples of the plasma generating apparatus include helicon and microwave using a capacitively coupled plasma source, inductively coupled plasma source, and plasma wave, plasma source) have been proposed. Among them, an inductively coupled plasma generation source capable of forming a high-density plasma at a low operating pressure is widely used.

The inductively coupled plasma generator includes a chamber in which a plasma is generated, a gas inlet for supplying a reaction gas into the chamber, and a vacuum pump for maintaining the inside of the chamber in vacuum and discharging the reaction gas when the reaction is terminated . In order to plasmaize the reaction gas in the chamber, an antenna is installed mainly on the chamber, a radio frequency source (RF source) is connected to the antenna as a plasma source, and an impedance matching When radio frequency power is applied from a radio frequency power source, radio frequency power, that is, radio frequency potential and current are applied to the antenna. An electromagnetic field is formed in the space inside the chamber by the applied radio frequency potential and an induced electromagnetic field is formed do. At this time, the reaction gas inside the chamber obtains sufficient energy for ionization from the applied induced electromagnetic field and forms a plasma. The formed plasma is induced by another radio frequency power source which applies a negative DC bias voltage to perform a predetermined process.

Such an inductively coupled plasma generating apparatus or plasma generating source has an advantage that a high density plasma can be formed at a low operating pressure. Particularly, in the case of a plasma generating apparatus used in a semiconductor manufacturing process, an inductively coupled plasma generating apparatus is advantageous in straightness in the course of an etching process or the like compared with a capacitive plasma generating apparatus, There are advantages.

On the other hand, in a conventional planar spiral antenna or coil type antenna widely used for a plasma generating apparatus, electromagnetic waves are formed in a large central portion with respect to an antenna, and the density distribution of the inductively coupled plasma generated thereby is The density is high at the center portion and has a shape decreasing toward the outer periphery, that is, toward the edge of the reactor. This is mainly caused by the decrease of the plasma density from the center portion to the outer portion due to the resistance of the coil-shaped antenna itself, and furthermore, the plasma density tends to be increased due to the difference in the process conditions and the deterioration even in the same equipment.

Accordingly, in order to efficiently perform a mass production and mass processing such as a process on a large-area substrate, formation of a plasma having a uniform distribution over a wide space is required, but a conventional planar spiral antenna satisfies these conditions It can not be done. Particularly, a difference in etch ratio and uniformity between the central portion and the outer portion may be generated, and the process yield may be adversely affected.

Korean Patent Laid-Open Publication No. 1999-0080959 Korean Patent Publication No. 2004-0062846

An embodiment of the present invention provides an antenna for an inductively coupled plasma generator for uniform formation of a plasma.

An embodiment of the present invention provides a method of controlling an antenna for an inductively coupled plasma generator for uniform formation of a plasma.

An embodiment of the present invention provides an inductively coupled plasma generator comprising an antenna for an inductively coupled plasma generator for uniform formation of plasma.

The antenna for an inductively coupled plasma generator according to an embodiment of the present invention includes at least one arc-shaped coil piece, wherein the coil piece is perpendicular to the vertical part from the central part to the outer part, And may include an inclined portion that is inclined with respect to the vertical portion so as to have a large surface area with respect to the horizontal surface.

The inclined portion may have an inclination angle with respect to the vertical portion within a range of 0.1 to 90 degrees, preferably 10 to 80 degrees, more preferably 30 to 60 degrees.

A control method of an antenna for an inductively coupled plasma generator according to an embodiment of the present invention includes at least two or more arc-shaped coil pieces, wherein each coil piece has a vertical portion, A radio frequency power source is applied to an antenna for an inductively coupled plasma generator including an inclined portion inclined to the vertical portion and a variable capacitor electrically connected to the coil portion so as to have a large surface area with respect to a horizontal plane perpendicular to the portion, And a power control step of controlling the variable capacitor so that higher radio frequency power is applied to the coil part located farther from the outer periphery than the center part around the antenna among the coil pieces.

A control method of an antenna for an inductively coupled plasma generator according to an embodiment of the present invention includes at least two or more arc-shaped coil pieces, wherein each coil piece has a vertical portion, And a voltage current sensor electrically connected to the coil piece, wherein the inclined part is inclined with respect to the vertical part, has a large surface area with respect to a horizontal plane perpendicular to the part, and is electrically connected to the coil piece. Measuring a voltage or current or voltage and current of a coil piece connected to the voltage current sensor by a voltage current sensor by applying a radio frequency power source to the antenna, A power supply for controlling a variable capacitor electrically connected to the coil unit so that the frequency power is applied; It can include.

An apparatus for generating an inductively coupled plasma according to an embodiment of the present invention includes a chamber in which a plasma is formed and a chamber in which a workpiece is placed, a window formed in a chamber opposed to the workpiece, an antenna provided on the window, Wherein the antenna includes at least one arc-shaped coil piece, wherein the coil piece extends from a central portion to an outer portion around a vertical portion and an antenna, and a horizontal plane perpendicular to the vertical portion And may include inclined portions inclined with respect to the vertical portion so as to have a large surface area.

According to the present invention, by changing the shape of the antenna, which is one of the components that can directly affect plasma formation, physical and / or electrical control, it is possible to form a uniform electromagnetic field as a whole from the central portion to the outer portion of the antenna, It is possible to form a uniform plasma, thereby making it possible to uniformly and precisely process an object to be processed such as a semiconductor element or the like.

In addition, it is possible to correct an unevenness of an electromagnetic field and / or a non-uniformity of a plasma in an antenna, particularly before and after a semiconductor manufacturing process, and / or to interlock the plasma generating device It is possible to prevent waste of raw materials such as a processed body and a reaction gas, and to prevent malfunction or contamination of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram showing the configuration of an antenna for an inductively coupled plasma generator according to an embodiment of the present invention. Fig.
2 is a circuit diagram schematically showing a configuration of an antenna for an inductively coupled plasma generator according to an embodiment of the present invention.
3 is a schematic diagram showing an inductively coupled plasma generating apparatus according to an embodiment of the present invention.
4 is a flowchart illustrating an operation sequence of the inductively coupled plasma generator according to the embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to clearly understand the technical idea of the present invention, the illustration and description of the components not related to the present invention will be omitted in order to illustrate the antenna for the inductively coupled plasma generator according to the specific embodiments of the present invention .

As shown in FIG. 1, the antenna 31 for the inductively coupled plasma generator according to the embodiment of the present invention may include at least one arc-shaped coil piece 311. The coil piece 311 has an inclined portion inclined with respect to the vertical portion 311a so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical portion 311a from the central portion to the outer portion with respect to the vertical portion 311a and the antenna 311b. That is, the antenna as described above can be formed by dividing the plate-shaped coil into a plurality of coil pieces, and forming a part of the coil piece (s) as an inclined portion.

1, a first coil piece 311 constituting an inner coil piece and including a first vertical part 311a and a first inclined part 311b, and a second coil part 311 constituting outer coil pieces, And a third coil piece 313 including a third vertical part 313a and a third inclined part 313b including a first coil part 312a and a second inclined part 312b, It is to be understood that the antenna may be configured to include an appropriate number of coil pieces or pieces, if desired.

That is, the antenna 31 for the inductively coupled plasma generator according to the embodiment includes at least one or more, preferably a plurality of arc-shaped coil pieces, and at least one of the coil pieces has a vertical portion and an antenna The inclined portion may be inclined with respect to the vertical portion so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical portion from the central portion to the outer portion.

Therefore, the antenna for the inductively coupled plasma generator according to the embodiment can include the coil piece (s) including both the vertical part and the inclined part, and also the arc-shaped coil piece (s) having only the vertical part .

As described above, the antenna according to the embodiment configured to include the inclined portion is formed by dividing the coil pieces into an appropriate number, and the electromagnetic pieces for generating plasma are induced in the chamber by making the coil pieces have an arc shape, In order to compensate for the attenuation of the electromagnetic field due to the resistance of the antenna itself and the nonuniformity of the plasma formation due to the resistance of the antenna itself as the distance from the central portion of the antenna is increased in the coil pieces of the antenna, So that the electromagnetic field applied to the horizontal plane parallel to the antenna is more uniformly induced. The coil piece is formed by rounding a plate material formed of a material having excellent electric conductivity, preferably copper, more preferably, oxygen free copper, and forming a vertical part by vertically positioning the plate material, So as to have a predetermined inclination angle.

The inclined portion may have an inclination angle with respect to the vertical portion within a range of 0.1 to 90 °, preferably 10 to 80 °, more preferably 30 to 60 °, and when the inclined portion has an inclination angle of less than 0.1 °, The inclination of the inclined portion may become too close to the vertical portion, and the inclination of the inclined portion may be in the range of 0.1 to 90 degrees It may not provide a different effect from the case where the inclination angle is within the range. When the inclination angle is 90 °, it means that the inclined portion is in a horizontal state in which the inclined portion is completely perpendicular to the vertical portion, meaning that the inclined portion can maximally affect the increase of the surface area and thus the distribution of the electromagnetic field do.

The inclination angle of the inclined portion may preferably have an inclination angle within a range of 10 to 80 degrees, more preferably within a range of 30 to 60 degrees, and the inclination angle of the inclined portion may be changed within a range of 30 to 60 degrees The variation of the surface area according to the inclination angle change of the inclined portion becomes smaller and the influence on the distribution of the electromagnetic field can also be reduced as the closer to 90 deg. Particularly, the inclined portion makes it possible to make the electromagnetic field induced by the antenna to have a certain directionality so as to exhibit directivity at the density of the plasma or the like, thereby enhancing the machining accuracy or enhancing the degree of machining.

The inclined portion may further include a driving portion for adjusting a surface area with respect to a horizontal plane. Although not shown for the sake of simplification of the drawings, the driving unit can be preferably an electric motor, and the inclined portion is mechanically connected to the rotary shaft of the electric motor and / or the rotary shaft of the speed reducer connected to the electric motor, So that the inclination angle can be adjusted to be different. The inclined portion of the driving portion and the coil piece may be connected to each other by an insulator electrically insulating the driving portion and the inclined portion so as not to affect the electrical characteristics of the coil piece. A geared motor designed to have an appropriate reduction ratio may be used to simplify the construction of the apparatus.

Further, as shown in Fig. 2, the coil piece constituting the antenna 31 may further include variable capacitors VC1, VC2, and VC3. 2, the first coil piece 311 constituting the inner coil piece includes the first variable capacitor VC1 and the second coil piece 312 constituting the outer coil pieces is connected to the second variable capacitor VC2 And the third coil piece 313 is shown as including the third variable capacitor VC3, it may include an appropriate number of coil pieces (s) and variable capacitors electrically connected thereto as needed It should be understood that the antenna may be configured to < RTI ID = 0.0 >

The variable capacitor (s) function to apply different currents and / or radio frequency powers to each coil segment (s) that are electrically connected to each. The variable capacitor (s) may further include a driver for adjusting the capacitance thereof. Although not shown for the sake of simplification of the drawings, the driving unit may be an electric motor, and a variable capacitor is mechanically connected to the rotary shaft of the electric motor and / or the speed reducer connected to the electric motor to rotate the variable capacitor Can be controlled.

The driving part and the variable capacitor of the coil piece may be connected to each other by an insulator electrically isolating the driving part and the variable capacitor from each other, so that the electric characteristics of the coil piece are not affected. A geared motor designed to have an appropriate reduction ratio may be used to simplify the construction of the apparatus. Variable capacitors are a kind of capacitor that can change its capacitance intentionally and repeatedly either mechanically or electronically.

Further, as shown in Fig. 2, the coil piece may further include a voltage current sensor. 2, the first coil piece 311 constituting the inner coil piece includes the first voltage current sensor VS1, the second coil piece 312 constituting the outer coil pieces is the second voltage current sensor VS1, (VS2), and the third coil piece 313 is shown as including the third voltage current sensor (VS3), it is also possible to include an appropriate number of coil pieces (s) and a voltage It should be understood that the antenna may be configured to include current sensors. The voltage current sensor is a type of sensor for measuring a voltage and / or a current and is electrically connected to a coil piece to measure the voltage and / or current of the coil piece.

A control method of an antenna for an inductively coupled plasma generator according to an embodiment includes at least two arc-shaped coil pieces, wherein each coil piece is perpendicular to a vertical portion from a central portion to an outer portion, A radio frequency power source is applied to an antenna for an inductively coupled plasma generator having a slope part inclined with respect to a vertical part and a variable capacitor electrically connected to a coil part so as to have a large surface area with respect to a horizontal plane, And a power control step of controlling the variable capacitor so that higher radio frequency power is applied to the coil piece located farther from the outer periphery than the center part around the antenna.

The power control step controls the variable capacitors connected to at least two or more arc-shaped coil pieces constituting the antenna for the inductively coupled plasma generator according to one specific embodiment of the present invention as described above, A higher radio frequency power is applied to the coil part located farther from the center part than the center part of the antenna, thereby allowing the electromagnetic field to be stronger or weaker on the far side from the center with respect to the antenna, The plasma can be generated more uniformly.

A control method of an antenna for an inductively coupled plasma generator according to an embodiment includes at least two or more arc-shaped coil pieces, wherein each coil piece is perpendicular to a vertical portion from a central portion to an outer portion, A variable capacitor electrically connected to the coil piece, and a voltage current sensor electrically connected to the coil piece so as to have a large surface area with respect to the horizontal plane of the inductively coupled plasma generator, Measuring a voltage or current or voltage and current of the coil piece connected to the voltage current sensor by a voltage current sensor by applying a frequency power source to the coil piece; A power control step of controlling a variable capacitor electrically connected to the coil part to be applied It should.

In the power control step, the variable capacitors connected to the at least two arc-shaped coil pieces constituting the antenna for the inductively coupled plasma generator according to the above-described embodiment are individually controlled, and the voltage Or a higher radio frequency power can be applied to the coil part located farther from the outer periphery than the center part around the antenna among the respective coil pieces based on the current value so that an electromagnetic field So as to induce a stronger or weaker induction, thereby making the plasma more uniformly generated. In Fig. 2, the symbol "C / H" means a chamber.

According to the control method of the antenna as described above, for the purpose of plasma density control, the user can form a current change to be assigned to the antenna by a simple operation on the controller by controlling the voltage current sensor, the variable capacitor and the driving unit for controlling the same . By this function alone, linear current proportional characteristic, which is one of the characteristics of the variable capacitor, can be shown and stable control can be realized. In addition, the voltage / current sensor may further include an integrator for interpreting the integrated circuit, thereby enabling stable control of the antenna. In addition, there is an unexpected problem during the deterioration and use of the antenna It is possible to make it possible to realize an interlock or the like of the apparatus.

3, the inductively coupled plasma generating apparatus 1 according to the embodiment includes a chamber 11 in which a plasma is formed and in which a workpiece 14 is placed, a chamber 11 opposed to the workpiece 14 And a gas supply part (12) for supplying a reaction gas into a chamber (11) provided on a window (17) of the antenna (31) formed in the chamber (11) 31 has at least one arc-shaped coil piece, wherein the coil piece has a slope inclined with respect to the vertical part so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical part from the center part to the outer part part with respect to the vertical part and the antenna .

The chamber 11 provides a space 18 in which the plasma 16 is formed and preferably the chamber 11 is fluidly connected to a vacuum pump 13, It is possible to easily make the reaction gas into a plasma state by evacuating the interior of the processing chamber 11 and discharging the reaction gas or the like when the processing of the processing object 14 is completed.

The chamber 11 may be made of a metal material such as aluminum and stainless steel, or may be made of a coated metal, for example, anodized aluminum. Alternatively, the chamber 11 may be made entirely of an electrically insulating material such as quartz, ceramic, or any other material suitable for the intended plasma process to be performed Can also be produced. In such a case, it may not be necessary to form the window 17 made of a separate dielectric.

The workpiece 14 is subject to processing by plasma, and may be a wafer or the like in a semiconductor manufacturing process. The work piece 14 can be placed on the support 15 and the support 15 can be biased by receiving bias power from the at least one bias power source through the impedance matcher 19. [

Although not shown in the drawing, DC power can be supplied from the DC power source to the support 15. When the bias power is supplied from two or more bias power sources, each bias power may have a different frequency. Depending on the process characteristics, the support 15 may not be biased at all. The support 15 may be an electro-static chuck (ESC) or a mechanical chuck.

A window 17 made of a window, preferably a dielectric, may be formed at a position opposite to the workpiece 14 in the chamber 11, and the antenna 31 according to the embodiment may be formed in the chamber 11 As shown in FIG. An impedance matcher 32 and a radio frequency power source 33 are electrically connected to the antenna 31 to apply radio frequency power to the antenna so that a plasma is formed in the chamber 11.

The gas supply 12 is also referred to as an "injector ", which functions to introduce the reaction gas into the chamber 11 and is disposed on the top or side of the chamber 11, So that the reaction gas can be smoothly injected into the chamber 11.

The antenna 31 may be configured in series or in parallel as required. Particularly, in the case of semiconductor equipment, the antenna 31 has a circular shape. In the case of a large-diameter or large-area facility, a square or polygonal Shape.

FIG. 4 illustrates an operation sequence of the antenna for an inductively coupled plasma generator according to an embodiment of the present invention. That is, as shown in FIG. 4, a radio frequency is applied to an inductively coupled plasma generator, impedance matching is performed, a radio frequency is transmitted to an antenna end, and a current / voltage value of a center portion and an outer portion of the antenna are measured After that, it is determined whether there is a significant difference in the current / voltage value between the coil pieces constituting the antenna. If there is a significant difference, the variable capacitor is controlled or the inclination angle of the coil is adjusted, Can be adjusted.

After measuring (remeasurement) the current / voltage values at the center and the outside of the antenna, it is determined whether there is a significant difference in the current / voltage values between the coil pieces constituting the antenna. After the significant difference is eliminated, an electromagnetic field is generated to generate an induction electric field inside the chamber, and a gas reaction and plasma generation can be performed, thereby enabling a predetermined process to be performed.

According to the inductively coupled plasma generating apparatus including the antenna for the inductively coupled plasma generator according to the above-described embodiment, the inclined portion is formed on the coil piece (s) constituting the antenna, And to further control the distribution of the electromagnetic field by physically adjusting the inclined portion of the coil piece (s) constituting the antenna before and after the generation of the plasma, and / (S) can be physically and / or electrically controlled so that the current and / or power applied to the variable capacitor (s) are fed differentially to allow further control of the distribution of the electromagnetic field to achieve uniform formation of the electromagnetic field .

In addition, it is thereby possible to enable uniform plasma formation in the chamber. Further, it is possible to electrically connect the voltage current sensors to the respective coil pieces (s) constituting the antenna, thereby making it possible to interlock the entire device when current and / or power is abnormal.

According to the embodiments of the present invention, it is possible to control the process performance of the central part and the outer part of the substrate, which is a problem in a semiconductor manufacturing process, particularly a fine line width process. Particularly, It is possible to solve the problems of irregularity of the plasma density due to the omnipresence of the plasma.

In the foregoing, the present invention has been shown and described with reference to certain preferred embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventive concept as defined by the appended claims. You can do it.

1: Plasma generating device 11: Chamber
12: gas supply unit 13: vacuum pump
14: Work piece 15:
16: Plasma 17: Window
18: Space 19: Impedance Matcher
31: Antenna 32: Impedance Matcher
33: radio frequency power source 311: first coil part
311a: vertical part 311b: inclined part
312: second coil piece
312a: vertical portion 312b: inclined portion
313: third coil piece
313a: vertical part 313b: inclined part

Claims (10)

Wherein the coil piece includes at least one arc-shaped coil piece, wherein the coil piece includes a vertical portion and an inclined portion inclined with respect to the vertical portion so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical portion from the central portion to the outer portion, Antenna for Inductively Coupled Plasma Generating Device. The method according to claim 1,
Wherein the inclined portion has an inclination angle within a range of 0.1 to 90 degrees with respect to the vertical portion. 3. The method of claim 2,
Wherein the inclined portion has an inclination angle within a range of 10 to 80 degrees with respect to the vertical portion. The method of claim 3,
Wherein the inclined portion has an inclination angle within a range of 30 to 60 degrees with respect to the vertical portion. The method according to claim 1,
Further comprising a driving unit for adjusting the surface area of the inclined portion with respect to the horizontal plane. The method according to claim 1,
The antenna of claim 1, further comprising a variable capacitor. The method according to claim 1,
The antenna for an inductively coupled plasma generator according to claim 1, further comprising a coil current sensor. Wherein each of the coil pieces has a vertical portion and an inclined portion inclined with respect to the vertical portion so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical portion from a center portion to an outer portion portion around the antenna, A radio frequency power source is applied to an antenna for an inductively coupled plasma generating device including a variable capacitor electrically connected to a coil, and a coil portion of each of the coil pieces located farther from the center portion And a power control step of controlling the variable capacitor so that high radio frequency power is applied to the inductively coupled plasma generator. Wherein each of the coil pieces has a vertical portion and an inclined portion inclined with respect to the vertical portion so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical portion from a center portion to an outer portion portion around the antenna, A radio frequency power source is applied to an antenna for an inductively coupled plasma generator including a variable capacitor electrically connected to a coil and a voltage current sensor electrically connected to the coil, Measuring the voltage or current or the voltage and current of the connected coil piece and controlling the variable capacitor electrically connected to the coil piece so that a higher radio frequency power is applied to the coil piece having a low current among the coil pieces Wherein the step of controlling the antenna comprises the steps of: A plasma is formed and includes a chamber in which a workpiece is placed, a window formed in a chamber facing the workpiece, an antenna provided on the window, and a gas supply unit for supplying a reaction gas into the chamber, Wherein the antenna comprises at least one circular coil piece having a sloping inclination relative to the vertical part so as to have a large surface area with respect to a horizontal plane perpendicular to the vertical part as the coil piece moves from the center part to the outer part part around the vertical part and the antenna And an inductively coupled plasma generator.

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