KR100731994B1 - Plasma treatment chamber with embedded outer ferrite core - Google Patents

Abstract

A plasma process chamber having a buried external ferrite core is provided to uniformly form high density plasma on a hollow region of the plasma chamber by burying plural external ferrite cores in a core burying unit to uniformly transmit induced electromotive force to a hollow region of a chamber housing. A susceptor(18) where a target substrate(16) is placed is formed in a hollow chamber housing(11). Plural core burying units(20a,20b) are formed on an upper portion of the chamber housing to be opposite to the susceptor. Plural ferrite cores(30) are buried in the core burying units. The ferrite cores are wound with inductive coils(32) to transmit induced electromotive force for forming plasma to a hollow region of the chamber housing. A first power supplying source(40) supplies AC power of a first frequency.

Description

Plasma treatment chamber with embedded external ferrite core {PLASMA PROCESS CHAMBER HAVING BURIED EXTERNAL FERRITE CORE}

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

1 is a perspective view schematically showing a plasma processing chamber according to a preferred embodiment of the present invention.

2 is a cross-sectional view of the plasma processing chamber of FIG. 1.

3 is a diagram illustrating an example in which a gas distribution plate is installed on an inner upper portion of a plasma processing chamber.

4 shows an example of a plasma processing chamber with a dual bias power source.

5 is a schematic perspective view of a plasma processing chamber in which four outer ferrite cores are embedded.

6 is a cross-sectional view of the plasma processing chamber of FIG. 5.

7 is a schematic perspective view of a plasma processing chamber in which one external ferrite core is embedded.

8 is a cross-sectional view of the plasma processing chamber of FIG. 7.

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

10: plasma processing chamber 11: chamber housing

12 chamber top 14 first gas inlet

15: hollow area 20a-20d: core buried part

30: ferrite core 32: induction coil

The present invention relates to a plasma source for processing a semiconductor substrate, and more particularly, to a plasma processing chamber having an external ferrite core embedded in an upper portion of the plasma processing chamber.

Due to various factors such as ultra miniaturization of semiconductor devices, an increase in substrate size, and the emergence of new materials to be treated, further improvements in substrate processing technologies are required in the semiconductor manufacturing process. Particularly, in the field of dry etching process or physical / chemical vapor deposition as a semiconductor manufacturing process using plasma, technology development for a plasma source capable of uniformly obtaining high density plasma using a magnetic field has been made in response to such technical requirements. .

In general, lowering the pressure of the plasma reaction tube increases the average free distance of ions, which increases the energy of ions colliding with the wafer and reduces scattering between the ions, which is known to be advantageous for anisotropic etching. However, when the pressure is lowered, the electrons also increase the average free distance, which reduces the collision with neutral atoms, making it difficult to maintain the plasma state. Therefore, a technique has been proposed to maintain the plasma at low pressure by increasing the frequency of collision with the neutral atoms by increasing the moving distance of electrons by using the magnetic field to maintain the plasma at low pressure.

In addition, as the substrate size increases, the size of the plasma reaction chamber in which the substrate is processed also increases, in which case it is difficult to uniformly distribute the plasma inside the plasma reaction chamber. Therefore, techniques for using a magnetic field to maintain a uniform plasma density inside the plasma reaction chamber have been proposed.

Techniques using permanent magnets have been proposed to form a uniform plasma inside the plasma reaction chamber. For example, techniques have been proposed, such as mounting a permanent magnet on top of a reaction tube, or rotating on top. Alternatively, the substrate may be rotated to allow a relatively uniform substrate treatment.

In the case of using permanent magnets, the uniformity can be improved relatively simply because they are small in size, simple to install, and do not require external power supply. However, the uniformity of the magnetic field is not good and the strength of the magnetic field is not controllable. When rotating a substrate or rotating a permanent magnet, there exists a burden for constructing a rotating structure.

Accordingly, an object of the present invention is to provide a self-reinforced plasma source having a ferrite core assembly for forming an annular plasma in the reaction chamber to more uniformly generate and maintain a high density plasma in the plasma reaction chamber.

One aspect of the present invention for achieving the above technical problem relates to a plasma processing chamber having an embedded external ferrite core. The plasma processing chamber of the present invention comprises: a hollow chamber housing provided therein with a susceptor on which a substrate to be processed is placed; A plurality of core buried portions formed in an upper portion of the chamber housing opposite the susceptor; A plurality of ferrite cores embedded in a plurality of core embedding parts, each of which induction coils are wound to transfer induced electromotive force for plasma formation to the hollow region of the chamber housing; And a first power supply source for supplying AC power at a first frequency to the induction coil.

Preferably, the ferrite core has a rod shape, and the core embedding portion has a volume embedding area in which rod-shaped ferrite cores can be embedded.

Preferably, the plurality of core embedding portions in which the ferrite core is embedded is arranged in at least one of a parallel arrangement structure, a radial arrangement structure, or a matrix arrangement structure on top of the chamber housing.

Preferably, it comprises a first gas inlet formed between the plurality of core buried parts.

Preferably, the gas distribution plate is provided between the core embedding parts.

Preferably, it includes a gas supply passage provided in the core buried portion and a second gas inlet formed in the gas supply passage and opened into the chamber housing.

Preferably, the first gas inlet is inputted with a first process gas and the second gas inlet is inputted with a second process gas different from the first process gas.

Preferably, the core embedding portion comprises a cooling water supply channel.

Preferably, the core embedding portion is composed of an insulating member.

Preferably, the core embedding portion is composed of an insulating member and includes an electrode grounded to the bottom face opposite to the susceptor.

Preferably, the induction coils wound around the plurality of ferrite cores are electrically connected to the first power source in any one of series, parallel, or a combination of series and parallel.

Preferably, the susceptor has a single bias structure and includes a second power supply for supplying AC power at a second frequency to the first bias power.

Preferably, the susceptor has a dual bias structure, and has a second power supply for supplying a first bias power at a second frequency, and a third power supply for supplying a second bias power at a third frequency at a frequency different from the second frequency. It includes.

According to another feature of the invention, the plasma processing chamber comprises: a hollow chamber housing having a susceptor on which a substrate to be processed is disposed; A core buried portion formed in an upper portion of the chamber housing opposite the susceptor; One or more ferrite cores embedded in the core embedding portion, the induction coil being wound to transfer induced electromotive force for plasma formation to the hollow region of the chamber housing; And a first power supply source for supplying AC power at a first frequency to the induction coil.

Preferably, the gas inlet provided in the core embedding portion and the gas distribution plate provided below the core embedding portion.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the embodiments of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings. In understanding the drawings, it should be noted that like parts are intended to be represented by the same reference numerals as much as possible. And detailed description of known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention is omitted.

(Example)

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, in which a plasma processing chamber having embedded external ferrite cores of the present invention will be described in detail.

1 is a perspective view schematically showing a plasma processing chamber according to a preferred embodiment of the present invention, Figure 2 is a cross-sectional view of the plasma processing chamber of FIG.

1 and 2, the plasma processing chamber 10 includes a susceptor 18 on which a substrate 16 to be processed is placed in a hollow chamber housing 11. The upper portion 12 of the chamber housing 11 is provided with two or more core buried portions 20a and 20b facing the substrate 16. Two or more core embedding portions 20a and 20b in which the ferrite core 30 is embedded are arranged in parallel to the upper portion 12 of the chamber housing 11. Ferrite cores 30 wound with induction coils 32 are embedded in the core embedding portions 20a and 20b, respectively.

The core buried portions 20a and 20b are preferably made of an insulating member, but may be made of a conductor. When composed of an insulating member, the core embedding portions 20a and 20b may include electrodes grounded to the bottom surface opposite to the susceptor 18. Although not specifically illustrated in the drawing, the core embedding parts 20a and 20b may include a cooling water supply channel.

The ferrite core 30 has a rod shape, and the core embedding portions 20a and 20b have a buried region of a volume where the rod-shaped ferrite core 30 can be embedded. The ferrite core 30 transmits induced electromotive force for plasma formation to the hollow region 15 of the chamber housing 11.

The induction coil 32 wound on the ferrite core 32 is connected in series to the first power source 40 for supplying the AC power of the first frequency, but in any one of parallel or series and parallel mixing schemes. Electrical connections can be made. The first frequency may be selected from 10khz ~ 100MHz. A matching circuit for impedance matching is typically configured between the first power supply 40 and the induction coil 32. The susceptor 18 is a single bias structure and is connected to a second power supply 42 that supplies an alternating current power of a second frequency to the first bias power. The second frequency is selected from 50khz ~ 2MHz, the power has a capacity of 500W ~ 5kW. Between the second power source 42 and the susceptor 18 is typically a matching circuit for impedance matching.

A first gas inlet 14 is formed between two or more core buried portions 20a, 20b. The first gas inlet 14 may be provided with two or more, in which case the gas is evenly spaced so as to distribute the gas evenly to the hollow region 15 of the chamber housing 11. Gas supply passages 36 are provided at the bottom of the core embedding portions 20a and 20b, respectively. The gas supply passage 36 has a second gas inlet 37 opened into the chamber housing 12. The second gas inlet 37 may be provided in two or more in one gas supply path 36, and is installed at equal intervals so that the gas is evenly distributed to the hollow region 15 of the chamber housing 11.

The same process gas may be input to the first and second gas inlets 14 and 37, but different types of process gases may be input. For example, a first process gas such as a source gas may be input to the first gas inlet 14, and a second process gas such as a carrier gas may be input to the second gas inlet 37. As shown in FIG. 3, a gas distribution plate 13 is installed between the core embedding portions 20a and 20b to more uniformly distribute the gas input to the first gas inlet 14 into the hollow region 15. Can be.

In the plasma processing chamber 10 of the present invention as described above, a plurality of external ferrite cores 30 are embedded in the core embedding portions 20a and 20b to uniformly induce electromotive force into the hollow region 15 of the chamber housing 11. By transmitting, the high density plasma may be more uniformly formed in the hollow region 15 of the plasma chamber 10. In addition, the core buried portions 20a and 20b include electrodes grounded at portions opposite to the susceptor 18, so that the bias discharge of the susceptor 18 can be more stably maintained. The uniformity of the plasma treatment may be improved by separately supplying different types of process gases to the first and second gas inlets 14.

4 shows an example of a plasma processing chamber with a dual bias power source. As shown in FIG. 4, the plasma processing chamber 10 is a dual bias structure, and includes a second power supply 42 for supplying a first bias power at a second frequency, and a third at a frequency different from the second frequency. The susceptor 18 may be connected to a third power supply 44 that supplies a second bias power of frequency, respectively. The second frequency is selected from 50khz ~ 2MHz, the power has a capacity of 500W ~ 5kW. The third frequency is selected from 10khz ~ 60MHz, the power has a capacity of 500W ~ 5kW.

FIG. 5 is a schematic perspective view of a plasma processing chamber in which four external ferrite cores are embedded, and FIG. 6 is a cross-sectional view of the plasma processing chamber of FIG. 5.

5 and 6, two or more, for example, four core buried portions 20a, 20b, 20c, 20d may be configured in parallel to the top 12 of the chamber housing 11. At this time, the core buried portions 20a, 20b, 20c, 20d are arranged in parallel at equal intervals as shown. Alternatively, the present invention may have various array structures such as a radial array structure or a matrix array structure. That is, the arrangement structure of the core buried portions 20a, 20b, 20c, and 20d can be changed to help uniform plasma formation in the hollow region 15 of the chamber housing 11.

In the gas input structure, as in the above-described example, the first gas inlets 14a, 14b, and 14c are configured between the core embedding parts 20a, 20b, 20c, and 20d, respectively, and the second gas inlets 36a, 36b, and 36c are provided. And 36d are formed in the core embedding sections 20a, 20b, 20c, and 20d. Although not shown in the drawing, the gas distribution plate may be configured such that the gas flowing from the first gas inlets 14a, 14b, and 14c is evenly distributed into the hollow region 15.

FIG. 7 is a schematic perspective view of a plasma processing chamber in which one external ferrite core is embedded, and FIG. 8 is a cross-sectional view of the plasma processing chamber of FIG.

7 and 8, as another example of the present invention, the plasma processing chamber 10 may include only one core buried portion 22 in the upper portion 12 of the chamber housing 11. The core embedding portion 22 is embedded with one ferrite core 34 on which the induction coil 36 is wound. However, it is also possible to embed multiple ferrite cores.

Induction coil 36 is connected to a first power source 40 that supplies AC power at a first frequency. The susceptor 18 is connected to a second power supply 42 that supplies a bias power at a second frequency. The susceptor 18 may be implemented in either a single bias structure or a double bias structure, as described above. Here, the gas inlet 15 is comprised in the core embedding part 36, and the gas distribution board 50 is comprised in the lower part. The lower part of the core embedding portion 36 or the gas distribution plate 50 is grounded. The core buried portion 36 may be formed of an insulator, and may include an electrode having a bottom surface grounded opposite to the susceptor 18.

As described above, the present invention has been described with reference to the embodiments shown in the drawings, but this is merely exemplary, and those skilled in the art to which the present invention pertains have various modifications and equivalent embodiments. You can see that it is possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to the plasma processing chamber having the embedded external ferrite core of the present invention as described above, a plurality of external ferrite cores are embedded in the core embedding portion to transfer the induced electromotive force uniformly to the hollow region of the chamber housing. High density plasma can be formed more uniformly in the void area. In addition, the core buried portion includes an electrode grounded in a portion opposite to the susceptor, so that the bias discharge of the susceptor can be more stably maintained. The uniformity of the plasma treatment may be improved by separately supplying different types of process gases to the first and second gas inlets. In addition, since the configuration of the ferrite core is simple and easy to install, the configuration and maintenance efficiency of the plasma processing equipment can be improved.

Claims (15)

A hollow chamber housing provided therein with a susceptor on which the substrate to be processed is placed; A plurality of core buried portions formed in an upper portion of the chamber housing opposite the susceptor; A plurality of ferrite cores embedded in a plurality of core embedding parts, each of which induction coils are wound to transfer induced electromotive force for plasma formation to the hollow region of the chamber housing; And A plasma processing chamber comprising a first power supply for supplying alternating current power of a first frequency to an induction coil. The plasma processing chamber of claim 1, wherein the ferrite core has a rod shape, and the core embedding portion has a volume embedding region in which a rod-shaped ferrite core can be embedded. 3. The plasma processing chamber of claim 2, wherein the plurality of core embedding portions in which the ferrite core is embedded is disposed in at least one of a parallel arrangement structure, a radial arrangement structure, or a matrix arrangement structure on top of the chamber housing. The plasma processing chamber of claim 1, further comprising a first gas inlet formed between the plurality of core buried portions. The plasma processing chamber of claim 4, further comprising a gas distribution plate disposed between the core embedding portions. The plasma processing chamber according to any one of claims 1 to 4, comprising a gas supply passage provided in the core embedding portion and a second gas inlet formed in the gas supply passage and opened into the chamber housing. 6. The plasma processing chamber of claim 5, wherein a first gas inlet is inputted with a first process gas and a second gas inlet is input with a second process gas different from the first process gas. The plasma processing chamber of claim 1, wherein the core embedding portion comprises a cooling water supply channel. The plasma processing chamber according to claim 1, wherein the core embedding portion is made of an insulating member. 2. The plasma processing chamber of claim 1, wherein the core embedding portion is comprised of an insulating member and includes an electrode grounded to a bottom facing the susceptor. The plasma processing chamber of claim 1, wherein the induction coils wound around the plurality of ferrite cores are electrically connected to the first power source in any one of series, parallel, or a combination of series and parallel. The method of claim 1 wherein the susceptor is a single bias structure, And a second power supply for supplying AC power at a second frequency to the first bias power. The method of claim 1, wherein the susceptor is a double bias structure, A second power supply for supplying a first bias power at a second frequency; And a third power supply for supplying a second bias power source at a third frequency at a frequency different from the second frequency. A hollow chamber housing provided therein with a susceptor on which the substrate to be processed is placed; A core buried portion formed in an upper portion of the chamber housing opposite the susceptor; One or more ferrite cores embedded in the core embedding portion, the induction coil being wound to transfer induced electromotive force for plasma formation to the hollow region of the chamber housing; And A plasma processing chamber comprising a first power supply for supplying alternating current power of a first frequency to an induction coil. 15. The plasma processing chamber of claim 14, further comprising a gas inlet provided in the core embedding portion and a gas distribution plate disposed under the core embedding portion.

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