WO2015080516A1 - Plasma processing device capable of plasma shaping through magnetic field control - Google Patents

Abstract

The present invention relates to a plasma processing device capable of plasma shaping through magnetic field control, the device comprising: a vacuum chamber having an inner space formed therein, a substrate being mounted in the inner space; an antenna positioned on the upper portion of the chamber to generate plasma in the inner space of the chamber; a magnetic field generation unit comprising a first magnetic field generation unit, which is arranged on the lower portion of the chamber and comprises at least one electromagnet coil, and a second magnetic field generation unit, which is arranged on a side surface of the chamber and comprises at least one electromagnet coil; and a control unit for controlling the current input to each of the electromagnet coils of the magnetic field generation unit such that, with reference to the center of the substrate mounted in the chamber, and, in an effective plasma space inside the chamber, the intensity of the magnetic field continuously increases in proportion to the distance in the outward direction in the horizontal space, and the intensity of the magnetic field increases in proportion to the distance in the upward direction in the vertical space. According to the present invention described above, the uniformity of plasma is increased in the entire inner space of the chamber such that a highly reliable plasma process can be performed even near the outer periphery of the substrate, and the plasma process can be performed more stably particularly with regard to a large-area substrate.

Description

[Revision 03.03.2015 by Rule 91] Plasma processing apparatus capable of plasma shaping through magnetic field control

The present invention relates to a plasma processing apparatus capable of plasma shaping through magnetic field control. More particularly, the present invention relates to a plasma processing apparatus, in which a plurality of magnetic field generators are disposed, and a plasma is formed through plasma shaping in a chamber by controlling a magnetic field through current control of each coil. It relates to a plasma processing apparatus for increasing the uniformity of.

Plasma generators include Helicon and microwave plasma sources using capacitively coupled plasma sources, inductively coupled plasma sources, and plasma waves. plasma source). Among them, inductively coupled plasma generators capable of easily forming high-density plasmas are widely used.

FIG. 1 illustrates an inductively coupled plasma generator, wherein the inductively coupled plasma generator 10 mounts a substrate to be processed in an accommodating space inside the chamber 15 to a holder of the substrate 16 and is inside the chamber. The antenna 17 is supplied with a reactive gas and an RF power source is connected to an upper portion of the chamber 15. When power is added from an impedance matched RF power source to the antenna 17, the RF is applied to the antenna 17. Power, ie RF potential and current, is applied. The applied RF potential forms a time-varying electric field in a direction parallel to the dielectric that isolates the antenna 17 and the RF current flowing through the antenna 17 creates a magnetic field in the space inside the reaction chamber 15 and is induced by this magnetic field. An electric field will be formed.

At this time, the reaction gas inside the chamber 15 obtains sufficient energy for ionization from the induction generated electric field and forms a plasma. The formed plasma is incident on the substrate installed in the substrate holder 16 to process the substrate. Such a plasma is generally called an inductively coupled plasma (ICP), and a device using the same is called an inductively coupled plasma processing apparatus.

In consideration of the productivity of the plasma processing process and the low pressure of the process for overcoming contaminant generation problems, it is preferable to increase the plasma density, and the plasma formed in the chamber 15 may be formed in the chamber 15. Since the density is higher by the induced electric field by the magnetic field than the electric field is formed to provide a plurality of magnetic field generating parts (11, 12, 13) by placing a permanent magnet on the outside of the chamber 15 to further increase the plasma density The method has been proposed (Patent Publication No. 10-2009-37343).

However, in the case of the permanent magnet or the electromagnet using the coil, in the case of the plasma processing apparatus using the magnetic field, it becomes difficult to uniformly control the plasma density of the center and the outer portion of the chamber interior space and thereby the plasma treatment. The reliability of product quality may be reduced by performing the process. For example, as the substrate is moved away from the center of the chamber during the plasma treatment process, the density of the plasma decreases, and the plasma treatment may not be performed properly. In particular, when processing a large-area substrate, the etching or the deposition process due to the non-uniformity of the plasma density may be a more serious problem.

Therefore, there is a need for a method of increasing the uniformity of the plasma density across the center and the outside of the substrate while at the same time obtaining a high plasma density in an inductively coupled plasma apparatus using a magnetic field.

 The present invention is to solve the problems of the prior art as described above, in the case of the inductively coupled high-density plasma processing apparatus using a magnetic field, because the plasma density of the center and the outer portion of the chamber inner space is not uniform and different from the plasma treatment It is to solve the problem that the reliability of the production of the product is poor.

In addition, the present invention, to increase the intensity of the magnetic field toward the outside in the horizontal direction around the substrate on the chamber inner space to suppress the occurrence of flute instability, and to propagate the R-wave inside the chamber To control the magnetic field to increase the strength of the magnetic field toward the top in the vertical direction with respect to the substrate, it is possible to increase the plasma density and at the same time obtain a more uniform plasma density throughout the center and the outside of the substrate to improve the quality of the process. I want to improve more.

In accordance with another aspect of the present invention, a plasma processing apparatus includes a vacuum chamber in which an internal space in which a substrate is mounted is formed; An antenna positioned above the chamber to generate plasma in an inner space of the chamber; A magnetic field generating unit including a first magnetic field generating unit disposed under the chamber and including at least one electromagnet coil and a second magnetic field generating unit including at least one electromagnet coil disposed at a side of the chamber; And continuously increasing the intensity of the magnetic field toward the outer side in the horizontal space, and increasing the strength of the magnetic field toward the upper side in the vertical space, in the effective plasma space in the chamber with respect to the center of the substrate mounted inside the chamber. And a control unit controlling a current input to each of the electromagnetic coils of the magnetic field generating unit.

The controller may control a current input to at least one coil of the coils of the first magnetic field generator in a direction opposite to the current input to the coil of the second magnetic field generator.

Preferably, the controller may control a current input to each of the electromagnet coils so that a predetermined magnetic field strength is generated at the center of the substrate on the effective plasma space in the chamber.

In addition, the first magnetic field generating unit may include a plurality of electromagnet coils disposed at the bottom of the chamber, and each of the electromagnet coils may be spaced apart from each other on the outside of the bottom of the substrate mounted inside the chamber to sequentially increase a larger radius. The controller may be configured to control a current input to at least one coil selected from a plurality of coils included in the first magnetic field generator in a direction opposite to the current input to the remaining coils.

On the other hand, the first magnetic field generating unit, a plurality of electromagnet coils disposed in the lower end of the chamber, each of the electromagnet coils are spaced apart from each other on the outside of the lower end of the substrate mounted in the chamber in order to sequentially have a larger radius The second magnetic field generating unit includes a plurality of electromagnet coils spaced apart from each other in the vertical direction of the chamber to surround the side circumference of the chamber, wherein the control unit is included in the first magnetic field generating unit. The current input to the at least one electromagnet coil selected from the plurality of electromagnet coils may be controlled in a direction opposite to the current input to the electromagnet coil of the second magnetic field generator.

Furthermore, the plasma processing apparatus of the present invention further includes a third magnetic field generating unit disposed above the chamber and including one or more electromagnet coils, wherein the controller is configured to receive a current input to the electromagnet coil of the third magnetic field generating unit. The second magnetic field generating unit may be controlled in the same direction as the current input to the electromagnet coil.

In addition, the plurality of electromagnet coils of the second magnetic field generating unit may be installed within a range from the outer side of the RF window provided in the upper end of the chamber to the horizontal space of the lower surface of the chamber.

According to the present invention, it is possible to perform a reliable plasma process in the vicinity of the substrate by improving the uniformity of the plasma as a whole inside the chamber, in particular, it is possible to perform a more stable plasma process for a large area substrate .

In addition, according to the present invention, the intensity of the magnetic field increases toward the outside in the horizontal direction around the substrate on the chamber internal space, eliminating the occurrence of flute instability, and propagating the R-wave inside the chamber. In order to control the magnetic field to increase the strength of the magnetic field toward the top in the vertical direction with respect to the substrate, a more uniform plasma density can be obtained at the same time as the center of the substrate and the outer edge of the substrate, the quality of the process It can be improved more.

1 shows an inductively coupled plasma generator,

2 shows a conceptual diagram of flute instability generated in a plasma processing apparatus,

3 shows an R-wave dispersion relation,

FIG. 4 shows a conceptual diagram of the magnitude of the magnetic field according to the Biot-Savart ’s law.

5 shows a configuration of a first comparative example compared with the plasma processing apparatus according to the present invention,

6 shows a magnetic flux density distribution diagram for the first comparative example,

7 shows a magnetic field distribution result graph for the first comparative example,

8 shows the configuration of the first embodiment as one configuration for the plasma processing apparatus according to the present invention,

9 shows a magnetic flux density distribution diagram for the first embodiment,

10 shows a magnetic field distribution result graph for the first embodiment,

11 shows the configuration of the second embodiment as one configuration for the plasma processing apparatus according to the present invention,

12 shows a magnetic flux density distribution diagram for the second embodiment,

13 shows a magnetic field distribution result graph for the second embodiment;

14 shows the configuration of the third embodiment as one configuration for the plasma processing apparatus according to the present invention,

15 shows a magnetic flux density distribution diagram for the third embodiment,

16 shows a magnetic field distribution result graph for the third embodiment,

17 shows the configuration of the fourth embodiment as one configuration for the plasma processing apparatus according to the present invention,

18 shows a magnetic flux density distribution diagram for the fourth embodiment,

19 shows a magnetic field distribution result graph for the fourth embodiment,

20 shows a magnetic flux density distribution diagram for the fifth embodiment according to the present invention,

21 shows a magnetic field distribution result graph for the fifth embodiment according to the present invention,

22 shows a magnetic flux density distribution diagram for a second comparative example compared with the plasma processing apparatus according to the present invention,

23 is a graph showing magnetic field distribution results for the second comparative example compared with the plasma processing apparatus according to the present invention;

24 shows the results according to representative control conditions in each case of Comparative Example 1, Comparative Example 2, and Examples 1 to 5,

25 to 29 show experimental results of measuring plasma density and electron temperature under the control conditions of FIG. 24.

In order to explain the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, the following describes exemplary embodiments of the present invention and looks at it with reference.

First, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention, and singular forms may include plural forms unless the context clearly indicates otherwise. Also in this application, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, one or more other It is to be understood that the present invention does not exclude the possibility of adding or presenting features or numbers, steps, operations, components, components, or combinations thereof.

In describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

A device having an antenna for generating an inductively coupled plasma, and separately from the magnetic field applied by a coil to obtain a high-density plasma using the characteristics of the magnetized plasma, the inventors of the present invention provide a magnetized inductively coupled plasma (M-ICP). Device), and the basic configuration thereof is cited in the inventor's previous registered patent No. 10-178847.

The present invention, in the magnetized inductively coupled plasma (M-ICP) device to grasp the spatial distribution of the magnetic field in the chamber according to the number and location of the electromagnet coil, the current strength and the direction of application and maximize the effect of the M-ICP device In order to form an optimized magnetic field distribution, an appropriate number of electromagnets are placed in an optimal position, and a method of shaping plasma by magnetic field control through control of each electromagnet is proposed.

In the M-ICP device, although the magnetic flux density applied to the center of the substrate is the same, depending on the spatial distribution of the magnetic field in the horizontal or vertical direction about the substrate, Discharge characteristics can vary significantly. In particular, the present inventors observed that the non-uniformity of plasma density, which may be a problem depending on the distribution of the magnetic field in the M-ICP device, is due to a phenomenon called flute instability, and the method to solve this problem is derived. As a result of the experiment, the present invention was confirmed by confirming the remarkable effect.

In order to understand the technical idea of the present invention, the flute-stability is described first. When a magnetic field is applied on a system in which a gradient of plasma density exists, a phenomenon called flute-stability may occur in a special situation. It becomes possible.

Flute-stability, also called Rayleigh-Taylor instability or Interchange instability, was discovered through research into plasma fusion. Referring to the conceptual diagram of the flute-intelligence shown in FIG. 2, the flute-intelligence is caused by a gravitational field F which acts in a direction opposite to the gradient of density generated in the magnetized plasma. As a possible phenomenon, it is similar to the phenomenon caused by the presence of gravity when a liquid that is heavier than a light liquid is present.

If it is assumed that the gravitational field F, which is not affected by the charge sign, operates in a direction perpendicular to the magnetic field B, the gravitational field F causes electrons and ions to move in opposite directions with respect to each other. Charge separation occurs. As a result, as shown in FIG. 2, an electric field E is formed.

As the shift occurs, perturbation is amplified, resulting in a phenomenon called flute-stability.

In a process plasma generator in which a magnetic field is applied, the curved magnetic field plays a role as a gravity field.

Such flute-stability causes the plasma density gradient to become unstable, thereby impairing the uniformity of the plasma density in the chamber internal space, thereby lowering the reliability of the plasma process.

Plasma perturbation phenomenon called flute-intelligence occurs when the density code and the gradient sign of the magnetic field are the same.

[Equation 1]

In general, since the plasma density decreases in the radial direction due to radial diffusion or loss in the wall, if it is reduced to the radial magnetic field strength, flute-stability phenomenon may occur and the nonuniformity of the plasma density may be worsened. will be. (Note: A.B.Mikhailovskii, Theory of plasma instabilities, Volume 2: Instabilities of an inhomogeneous plasma)

The inventors have found that the non-uniformity of plasma density caused by the magnetic field distribution in the M-ICP device is exacerbated by the flute-intelligence phenomenon by the combination of the plasma density decreasing effect along the radial outward direction and the radial magnetic field decreasing effect. In view of the fact that it can be avoided, experiments have been made by forming a magnetic field distribution that increases the magnetic field intensity in the opposite direction to prevent the situation, that is, plasma having a stable uniform density without flute-stability. Distribution was obtained.

Therefore, in the present invention, the generation of flute-intelligence is eliminated by controlling the spatial distribution of the magnetic field in the chamber. In particular, according to [Equation 1], the effective plasma space in the chamber is located on the horizontal space in the chamber. The outward direction increases the strength of the magnetic field to eliminate the occurrence of flute-stability.

Here, the effective plasma space refers to a space in the chamber including a horizontal space end and a vertical space end of the chamber with respect to the substrate as a space in which a plasma for performing a plasma process exists on a substrate mounted in the chamber. In some cases, it may be considered to include a horizontal space having a predetermined length wider than the substrate and a vertical space having a predetermined height from the substrate in consideration of the substrate size on which the process is to be performed.

On the other hand, it is possible to reduce or increase the magnetic field strength in the vertical direction through proper placement and control of the electromagnet, the present inventors to increase the strength of the magnetic field toward the upper direction on the vertical space with respect to the substrate in the effective plasma space in the chamber It has been observed that increasing can improve the efficiency of plasma generation in space in the chamber to further increase density.

The reason for this is that considering the R wave graph of FIG. 3, the magnetic field in the vertical direction must be increased to facilitate propagation of the R-wave in the chamber, and thus to the electron cyclotron resonance (ECR). This can be explained by the fact that electron heating can be performed to increase the plasma generation efficiency.

The M-ICP device of the embodiments to be described below may use an electron cyclotron resonance (ECR) generated by applying a magnetic field as an acceleration energy source of electrons, for example, having a frequency of 27.12 MHz. When using a RF generator (Radio frequency generator), the effect can be expected when the magnetic flux density is about 9.6Guass. If a microwave-based ECR plasma device with a frequency of 2.45 GHz requires a tremendous magnetic field of up to about 1 kG, an RF generator with a frequency of 27.12 MHz will require a minimum number of Gauss (ICP) at the center of the substrate. In this case, a magnetic field of up to 30 Gauss may be applied, so that the number of turns or current of the magnetic field coil may be lower, thereby facilitating a hardware configuration.

In other words, when the magnetic flux density of at least a few Guass is formed at the center of the substrate, a smooth plasma process can be performed on the substrate. When using a frequency of several GHz bands, a larger magnetic flux density can be easily formed at the center of the substrate. As the high current is applied to give high power, the diameter of the magnetic field coil needs to be increased and the number of turns needs to be large, so that the hardware configuration is not easy.However, when a frequency of several to several tens of MHz bands is used, relatively low current As applied, the diameter of the magnetic field coil may be relatively thin and the number of turns may be reduced, thereby facilitating a hardware configuration.

In the following embodiments, as a magnetic field generating unit, a first magnetic field generating unit and a second magnetic field generating unit are respectively installed in the lower and side surfaces of the chamber, and a third magnetic field generating unit is additionally installed in the upper portion of the chamber.

The magnetic field distribution according to the arrangement, the number of turns, and the current of the electromagnetic coils constituting each magnetic field generator can be predicted by calculation, etc. The magnitude of the magnetic field B determined by the current I flowing in the closed path C ′ is determined by the Bioshavar law. Savart's law) is represented by the following [Formula 2].

[Equation 2]

Therefore, based on Equation 2, the strength of the magnetic field at any position can be predicted given the position of the coil, the current flowing through it, and the like.

Based on such a condition, the number of windings and the position of each coil of the magnetic field generating unit to be applied to the embodiments may be determined. For example, the first magnetic field generating unit may be located near an exhaust pump at the bottom of the chamber. Two coils, Lower 1 and Lower 2, and as the second magnetic field generator, Coil Lateral 1 and Coil Lateral 2 near the outside of the horizontal line chamber of the substrate near the outside of the chamber at the bottom of the RF window, and additionally As the third magnetic field generating unit, a configuration in which coils Upper 1, Upper 2, and Upper 3 are disposed between an antenna box and a matching box may be considered.

At this time, the number of coil windings of the second magnetic field generating units Lateral 1 and Lateral 2, which are spatially limited by a window located on the side of the chamber, is 1000, respectively, and the remaining first magnetic field generating unit and the second magnetic field generating are generated. The number of coil windings included in the unit was set to 1400, respectively. If assuming that a current of 0.7 A is applied to all coils in the same direction, the magnetic flux density applied to the center of each substrate by the Bioshavar law can be obtained as shown in Table 1 below.

TABLE 1

As a result, it can be expected that the magnetic flux density at the center of the substrate in the chamber will be about 45.6 Gauss at most when the coils with the conditions according to [Table 1] are arranged.

Hereinafter, the experimental results according to the number and location of each electromagnetic coil constituting the magnetic field generating unit, the strength of the current and the direction of application.

5 shows the configuration of Case 1 as a first comparative example compared with the plasma processing apparatus of the present invention.

In the plasma processing apparatus 100 of FIG. 5, the horizontal linear chamber 150 of the coil Lateral 1 111 and the lower surface of the chamber 150 is located near the outside of the chamber 150 at the lower end of the RF window 180 as the second magnetic field generator. Coil Lateral 2 (112) was placed near the outside.

Then, the magnetic field distribution in FIG. 6 and the magnetic field distribution in FIG. 7 were measured by controlling the current input to the second magnetic field generating unit under the current control conditions shown in [Table 2]. The resulting graph was obtained.

TABLE 2

6 (a), (b), (c) and (d) are magnetic flux density distribution diagrams corresponding to Case 1-1 to Case 1-4 of Table 2, respectively, sequentially in the chamber 150. FIG. 7 illustrates a magnetic flux density distribution in a right space obtained by cutting a space along a vertical axis. In FIG. 7, (a) shows a magnetic flux density graph in a horizontal direction about a substrate, and (b) shows a magnetic flux density distribution in a vertical direction about a substrate. A magnetic flux density graph is shown.

The currents supplied to the coil Lateral 1 (111) and the Coil Lateral 2 (112) of the second magnetic field generating unit are forward in accordance with the configuration and current conditions of the plasma processing apparatus 100 according to Cases 1-1 to Case 1-4. As shown in FIG. 7, in the case of Case 1-1 and Case 1-3, the magnetic field distribution in the horizontal direction is kept constant and the magnetic field in the vertical direction is slightly decreased, as described above. Instability occurs, making it impossible to uniformly form the plasma density over the entire effective plasma space.

As shown in FIG. 7, the current supplied to the coil Lateral 1 (111) in the second magnetic field generating unit is controlled in the forward direction and the current supplied to the coil Lateral 2 (112) is controlled in the reverse direction. In the case of 1-4, the magnetic field in the horizontal direction and the magnetic field distribution in the vertical direction increase as the distance from the center of the substrate increases. In the case of Case 1-2, the magnetic flux density close to 0Gauss is formed in the center space of the substrate. It can be seen that in case 1-4, the magnetic flux density of approximately 1 Gauss band is formed in the center space of the substrate and increases as the magnetic flux density increases away from the center of the substrate. It can be seen that it decreases to 0Gauss and then increases again. In this case, as the magnetic field increases from the center of the substrate as a whole, the flute-intelligence phenomenon may be slightly reduced, but the magnetic flux density in the substrate center space is too low to substantially perform a plasma process on the substrate.

8 shows a configuration of Case 2 according to the first embodiment as an example of the plasma processing apparatus according to the present invention.

In the plasma processing apparatus 200 of FIG. 8, one coil lower 1 221 is disposed outside the intake vicinity of the turbo molecular pump as the first magnetic field generating unit, and the RF is used as the second magnetic field generating unit. The coil Lateral 1 211 is disposed near the outside of the chamber 250 at the lower end of the window 280 and the outside of the horizontal linear chamber 250 on the lower surface of the chamber 250.

The magnetic flux density distribution diagram of FIG. 9 is obtained by measuring the magnetic field distribution in the internal space of the chamber 250 by controlling the currents input to the first magnetic field generator and the second magnetic field generator under the current control conditions shown in Table 3 below. And a magnetic field distribution result graph of FIG. 10.

TABLE 3

9 (a) to 9 (c) are magnetic flux density distribution diagrams corresponding to Case 2-1 to Case 2-3 in Table 3, respectively, and the right space in which the interior space of the chamber 250 is cut along the vertical axis. In FIG. 10, (a) shows a magnetic flux density graph in a horizontal direction about a substrate, and (b) shows a magnetic flux density graph in a vertical direction about a substrate.

The current supplied to the coil lower 1 221 of the first magnetic field generator in accordance with the configuration and current conditions of the plasma processing apparatus 200 according to Cases 2-1 to Case 2-3 is the coil lateral of the second magnetic field generator ( 211) and the magnetic field strength continuously increases in the horizontal direction, and also increases in the vertical direction, as shown in FIG. 10 when controlling in a reverse direction different from the current supplied to the coil Lateral 2 212. It can be seen that the magnetic flux density is controlled at least 6Gauss and as high as 12Gauss in the substrate center space.

11 shows a configuration of Case 3 according to the second embodiment as an example of the plasma processing apparatus according to the present invention.

In the plasma processing apparatus 300 of FIG. 11, a coil lower 2 322 is disposed as a first magnetic field generating unit adjacent to an inlet of a turbo-molecular pump, and an RF window 380 is used as a second magnetic field generating unit. Coil Lateral 1 311 is disposed near the outside of the lower end of the chamber 350 and coil Lateral 2 312 is disposed near the outside of the horizontal line chamber 350 on the lower surface of the chamber 350.

And as a result of measuring the magnetic field distribution in the interior space of the chamber 350 by controlling the current input to the first magnetic field generating unit and the second magnetic field generating unit under the current control conditions of the following [Table 4] And a magnetic field distribution result graph of FIG. 13.

TABLE 4

12 (a) to 12 (c) are magnetic flux density distribution diagrams corresponding to Cases 3-1 to 3-3 of Table 4, respectively, in order to sequentially cut the inner space of the chamber 350 along the vertical axis. In FIG. 13, (a) shows a magnetic flux density graph in a horizontal direction about a substrate, and (b) shows a magnetic flux density graph in a vertical direction about a substrate.

The current supplied to the coil lower 2 322 of the first magnetic field generating unit under the configuration and current conditions of the plasma processing apparatus 200 according to Cases 3-1 to 3-3 is the coil lateral 1 of the second magnetic field generating unit. In the case of controlling in a reverse direction different from the current supplied to the 311 and the coil Lateral 2 312, it can be seen that the magnetic field strength gradually increases in the horizontal direction and the vertical direction as shown in FIG. 13. In the first embodiment of Figure 8 it can be seen that the magnetic flux density is similar to the result of controlling the current according to the above [Table 3].

That is, in case 3 of the second embodiment and case 2 of the first embodiment, when one coil lower is disposed at a different position in the lower part of the chamber and the same current control is performed, both case 2 and case 3 have a magnetic field strength in a horizontal direction. The magnetic flux density is continuously controlled, and the magnetic field strength increases gradually in the vertical direction, and the magnetic flux density is controlled at least 6Gauss and as high as 12Gauss in the substrate center space.

14 shows a configuration of Case 4 according to the third embodiment as an example of the plasma processing apparatus according to the present invention.

In the plasma processing apparatus 400 of FIG. 14, two coils Lower 1 421 and Lower 2 422 are disposed near a suction port of a turbo-molecular pump as a first magnetic field generating unit, and an RF is provided as a second magnetic field generating unit. Coil Lateral 1 411 is disposed near the outer side of the chamber 450 at the lower end of the window 480 and coil Lateral 2 412 is disposed near the outside of the horizontal linear chamber 450 on the lower surface of the chamber 450.

And as a result of measuring the magnetic field distribution in the internal space of the chamber 450 by controlling the current input to the first magnetic field generating unit and the second magnetic field generating unit under the current control conditions shown in Table 5 below, the magnetic flux density distribution diagram of FIG. And a magnetic field distribution result graph of FIG. 16.

TABLE 5

15 (a) to 15 (c) are magnetic flux density distribution diagrams corresponding to Cases 4-1 to 4-4 of Table 5, respectively, to sequentially show the right space in which the interior space of the chamber 450 is cut along the vertical axis. In FIG. 16, (a) shows a magnetic flux density graph with respect to the horizontal direction with respect to the substrate, and (b) shows a magnetic flux density graph with respect to the vertical direction with respect to the substrate.

The current supplied to the coils Lower 1 421 and Lower 2 422 of the first magnetic field generating unit is configured to correspond to the configuration and current conditions of the plasma processing apparatus 400 according to Cases 4-1 to 4-4. As shown in FIG. 16, when the magnetic field generator is controlled in a reverse direction different from the currents supplied to the coils Lateral 1 411 and the coil Lateral 2 412, the magnetic field strength continuously increases in the horizontal direction, and also in the vertical direction. It can be seen that the magnetic field strength gradually increases, and the magnetic flux density is controlled to about 6Gauss or more and 16Gauss as high as the substrate center space. In particular, it can be seen that the magnetic field strength increases rapidly in the horizontal and vertical directions when a larger current is supplied as shown in the result of Case 4-3.

17 shows a configuration of Case 5 according to the fourth embodiment as an example of the plasma processing apparatus according to the present invention.

In the plasma processing apparatus 500 of FIG. 17, two coils Lower 1 521 and Lower 2 522 are disposed near a suction port of a turbo-molecular pump as a first magnetic field generating unit, and an RF is used as a second magnetic field generating unit. Coil Lateral 1 511 is disposed near the outer side of the chamber 550 at the lower end of the window 580 and coil Lateral 2 512 is disposed near the outside of the horizontal linear chamber 550 on the lower surface of the chamber 550. In addition, as a third magnetic field generating unit, two coils Upper 1 531 and Upper 2 532 are disposed on the upper antenna box 570 of the chamber 550.

And as a result of measuring the magnetic field distribution in the interior space of the chamber 550 by controlling the current input to the first magnetic field generating unit, the second magnetic field generating unit and the third magnetic field generating unit under the current control conditions of the following [Table 6] A magnetic flux density distribution diagram of FIG. 18 and a magnetic field distribution result graph of FIG. 19 were obtained.

TABLE 6

18A to 18C are magnetic flux density distribution diagrams corresponding to Cases 5-1 to 5-3 of Table 6, respectively, in order to sequentially cut the inner space of the chamber 550 in a vertical axis. In FIG. 19, (a) shows a magnetic flux density graph in a horizontal direction about a substrate, and (b) shows a magnetic flux density graph in a vertical direction about a substrate.

The current supplied to the coil lower 1 521 of the first magnetic field generating unit under the configuration and current conditions of the plasma processing apparatus 400 according to Cases 5-1 to 5-5 is the coil lower 2 of the first magnetic field generating unit. 522, a control in a reverse direction different from the current supplied to the coil lateral 511 and the coil latral 2 512 of the second magnetic field generating unit and the coils Upper 1 531 and upper 2 532 of the third magnetic field generating unit. In this case, as shown in FIG. 19, it can be seen that the magnetic field strength continuously increases in both the horizontal direction and the vertical direction. Although the magnetic flux density is controlled to be about 2 Gauss in the center space of the substrate in the case 5-1, the magnetic flux density can be maintained at a predetermined level or more. It can be seen that the magnetic field strength in the vertical direction is rapidly increased by adding the third magnetic field generator.

As one configuration of the plasma processing apparatus according to the present invention, the configuration of the case 6 according to the fifth embodiment is the same as that of FIG. 17. 521 and Lower 2 522 are disposed, and the horizontal linear chamber of the coil Lateral 1 511 and the lower surface of the chamber 550 near the outside of the chamber 550 at the lower end of the RF window 580 as the second magnetic field generating unit. Coil Lateral 2 (512) was placed near the outside. In addition, as a third magnetic field generating unit, two coils Upper 1 531 and Upper 2 532 are disposed on the upper antenna box 570 of the chamber 550.

In addition, the current input to the first magnetic field generating unit, the second magnetic field generating unit, and the third magnetic field generating unit is controlled in the internal space of the chamber 550 according to the current control conditions shown in Table 7 below. As a result of measuring the magnetic field distribution, a magnetic flux density distribution graph of FIG. 20 and a magnetic field distribution graph of FIG. 21 were obtained.

TABLE 7

20 (a) to 20 (c) are magnetic flux density distribution diagrams corresponding to Case 6-1 to Case 6-3 in the Table 7, respectively, and the right space in which the interior space of the chamber 550 is cut along the vertical axis. In FIG. 21, (a) shows a magnetic flux density graph with respect to the horizontal direction with respect to the substrate, and (b) shows a magnetic flux density graph with respect to the vertical direction with respect to the substrate.

As a result of applying the current control condition of [Table 7], a result similar to the current control condition of [Table 6] was obtained. That is, the current supplied to the coil Lower 2 522 of the first magnetic field generating unit is obtained by the first control. Supplied to the coil lower 1 521 of the magnetic field generator, the coil lateral 511 and the coil late 2 512 of the second magnetic field generator, and the coil upper 1 531 and the upper 2 532 of the third magnetic field generator. As shown in FIG. 21, when the magnetic field is controlled in a different direction from the current, the magnetic field strength continuously increases in both the horizontal direction and the vertical direction. The magnetic flux density is about 6Gauss or higher and 16Gauss in the substrate center space. It can be seen that it is controlled.

On the other hand, as a second comparative example compared with the plasma processing apparatus according to the present invention, the configuration of Case 7 is arranged in the same manner as in FIG. 17, and the first magnetic field generating unit and the second magnetic field generating unit are arranged, and the third magnetic field generating unit is additionally arranged. It was.

In addition, the current input to the first magnetic field generating unit, the second magnetic field generating unit, and the third magnetic field generating unit is controlled in the internal space of the chamber 550 according to the current control conditions shown in [Table 8]. As a result of measuring the magnetic field distribution, the magnetic flux density distribution graph of FIG. 22 and the magnetic field distribution graph of FIG. 23 were obtained.

TABLE 8

FIG. 22 is a magnetic flux density distribution diagram corresponding to Case 7 of Table 8, and illustrates a magnetic flux density distribution in a right space obtained by cutting the internal space of the chamber 550 in a vertical axis. In FIG. A magnetic flux density graph is shown in the horizontal direction, and Axial shows a magnetic flux density graph in the vertical direction about the substrate.

As a result of supplying forward current in the same current direction to all of the first magnetic field generating unit, the second magnetic field generating unit, and the third magnetic field generating unit according to the current control conditions shown in [Table 8], as shown in FIG. It can be seen that the magnetic field strength is reduced in both the horizontal direction and the vertical direction. That is, when all currents inputted to the first magnetic field generator, the second magnetic field generator, and the third magnetic field generator are controlled in the same direction, the magnetic field decreases in both the horizontal and vertical directions, thereby causing the flute-stability phenomenon. It is not possible to uniformly form the plasma density over the entire effective plasma space.

The results according to representative control conditions in each case (Case) of Comparative Example 1, Comparative Example 2 and Examples 1 to 5 are summarized in FIG. 24, where the magnetic field strength B of the center of the substrate is the same as 7 Gauss. In the case of the embodiments 1 to 5 according to the present invention for controlling the current supplied to at least one of the coils included in the first magnetic field generating unit in a direction opposite to the other coils in the horizontal direction It can be seen that the intensity of both B (radial) and magnetic field B (Axial) in the vertical direction increases.

Furthermore, in the case of controlling the first magnetic field generating unit, the second magnetic field generating unit, and the third magnetic field generating unit under the control condition of FIG. 24, the plasma density and the electron temperature in the chamber are measured. The results of the experiment are shown in FIGS. 25 to 29.

25, 26 and 27 show the results of measuring the plasma density and plasma electron temperature for the process pressures of 1 mTorr, 5 mTorr and 10 mTorr, respectively, based on the 0.8 cm height from the substrate in the chamber (process gas: Ar, Plasma source power 1000W). As shown in FIGS. 25 to 27, an embodiment of the present invention controls the current supply direction of at least one electromagnet coil included in the first magnetic field generator differently from the current supply direction of the other electromagnet coils. 5 and Case 6 it can be seen that as the plasma density increases, the uniformity of the plasma in the horizontal direction is also improved. On the other hand, in the case of Comparative Examples for controlling all the current supply direction of the magnetic field generating unit in the case 1 and 7 it can be seen that there is no effect of increasing the plasma density and poor uniformity characteristics of the plasma.

If the electron temperature is too high, the charging of the electrons to the etching mask is severe, so that the ion is not vertically incident and deflected, which may cause a problem that the etching is not performed vertically. FIGS. 26 and 27 In all cases, the difference in electron temperature did not occur significantly, but in the case of FIG. 25 (1mTorr), cases 4, 5, and 6 of the embodiments of the present invention are more stable.

In addition, FIG. 28 shows plasma density and electron temperature measurement results in each case based on the center of the substrate. As shown in FIG. 28, Case 4, Case 5, and Case 6 which are embodiments of the present invention are relatively shown in FIG. It can be seen that the plasma density is improved and the electron temperature is also stable.

Furthermore, FIG. 29 illustrates nonuniformity of the plasma density in the horizontal direction on the chamber internal space. The radial nonuniformity of the radial direction may be represented by the following Equation 3, and the uniformity of the plasma density is 100 Non-uniformity).

In other words, the higher the non-uniformity, the more uniformly the plasma is distributed in the radial direction.

[Equation 3]

Where n _max represents the plasma highest density and n _min represents the plasma minimum density.

Looking at the non-uniformity shown in FIG. 29, it can be seen that the case of Case 4, Case 5 and Case 6, which is an embodiment of the present invention because the non-uniformity is relatively low, the plasma density in the horizontal direction becomes more uniform.

In particular, the case of Case 1 and Case 7, which is a comparative example that applies a magnetic field but supplies current to the electromagnetic coil in the same direction as compared to the ICP does not apply a magnetic field can be seen that the non-uniformity is increased and the uniformity deteriorates. On the other hand, when the current is supplied to at least one electromagnet coil in a direction opposite to the other electromagnet coils, the strength of the magnetic field increases as the distance from the chamber center increases in the horizontal direction, and the uniformity can be confirmed.

As described above, in the embodiment of the present invention, the first magnetic field generating unit includes one or two electromagnet coils, and the second magnetic field generating unit and the third magnetic field generating unit are respectively described as including two electromagnet coils. In order to easily explain the operating principle and effects according to the present invention, the first magnetic field generating unit, the second magnetic field generating unit and the third magnetic field generating unit optionally includes only one electromagnet coil or three or more according to the situation It may be modified to include an electromagnet coil.

According to the present invention, in order to eliminate the occurrence of flute-stability, the strength of the magnetic field increases toward the outside in the horizontal direction around the substrate in the chamber internal space, and the substrate is moved to propagate the R-wave into the chamber. Through the configuration of controlling the magnetic field to increase the strength of the magnetic field toward the upper portion in the vertical direction to the center, by improving the uniformity of the plasma throughout the interior of the chamber, a reliable plasma process can be performed in the vicinity of the substrate, in particular It is possible to more stably perform a plasma process for a large-area substrate.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments described in the present invention are not intended to limit the technical idea of the present invention but to explain, and the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (7)

1. A vacuum chamber in which an inner space in which the substrate is mounted is formed;

   An antenna positioned above the chamber to generate plasma in an inner space of the chamber;

   A magnetic field generating unit including a first magnetic field generating unit disposed under the chamber and including at least one electromagnet coil and a second magnetic field generating unit including at least one electromagnet coil disposed at a side of the chamber; And

   In the effective plasma space in the chamber with respect to the center of the substrate mounted inside the chamber, the intensity of the magnetic field is continuously increased in the outward direction on the horizontal space, and the strength of the magnetic field is increased in the upward direction on the vertical space. And a control unit for controlling a current input to each of the electromagnetic coils of the magnetic field generating unit.
2. The method of claim 1,

   And the control unit controls a current input to at least one coil of the coils of the first magnetic field generator in a direction opposite to a current input to the coil of the second magnetic field generator.
3. The method of claim 1,

   The control unit,

   And controlling a current input to each of the electromagnet coils so that a predetermined magnetic field intensity is generated at the center of the substrate on the effective plasma space in the chamber.
4. The method of claim 1,

   The first magnetic field generating unit,

   It includes a plurality of electromagnet coils disposed at the bottom of the chamber,

   Each of the electromagnet coils are spaced apart from each other at the bottom outer side of the substrate mounted inside the chamber so as to have a larger radius sequentially.

   The control unit is characterized in that for controlling the current input to at least one coil selected from the plurality of coils included in the first magnetic field generating unit in a direction opposite to the current input to the remaining coil.
5. The method of claim 1,

   The first magnetic field generating unit,

   It includes a plurality of electromagnet coils disposed at the bottom of the chamber,

   Each of the electromagnet coils are spaced apart from each other at the bottom outer side of the substrate mounted inside the chamber so as to have a larger radius sequentially.

   The second magnetic field generating unit,

   A plurality of electromagnet coils disposed to be spaced apart from each other in a vertical direction of the chamber to surround a side circumference of the chamber,

   The controller may control a current input to at least one electromagnet coil selected from a plurality of electromagnet coils included in the first magnetic field generator in a direction opposite to the current input to the electromagnet coil of the second magnetic field generator. Plasma processing apparatus.
6. The method according to any one of claims 1 to 5,

   A third magnetic field generator disposed on the chamber and including one or more electromagnet coils,

   And the control unit controls the current input to the electromagnet coil of the third magnetic field generator in the same direction as the current input to the electromagnet coil of the second magnetic field generator.
7. The method according to any one of claims 1 to 5,

   The plurality of electromagnet coils of the second magnetic field generator,

   Plasma processing apparatus characterized in that installed in the range from the outside of the RF window (RF window) provided in the upper end of the chamber to the horizontal space of the lower surface of the chamber.

Images