KR101358780B1 - Plasma reactor having inductively coupled plasma source with heater - Google Patents

Abstract

The present invention relates to an inductively coupled plasma reactor. The plasma reactor includes a reactor body having a plasma induced discharge region, an inductively coupled plasma source for forming an inductively coupled plasma inside the reactor body, a heater electrode installed in the inductively coupled plasma source to control the internal temperature of the reactor body, and a heater electrode It includes a heater driving circuit for supplying power to control the temperature of the inner region of the reactor body. The inductively coupled plasma reactor can improve the process reproducibility by controlling the internal temperature of the plasma reactor appropriately and precisely according to the process characteristics, and reduce the contamination inside the reactor by appropriately performing temperature control related to internal contamination. Process yield can be improved.

Plasma, antenna, inductive coupling

Description

Plasma reactor with inductively coupled plasma source with heater {PLASMA REACTOR HAVING INDUCTIVELY COUPLED PLASMA SOURCE WITH HEATER}

The present invention relates to an inductively coupled plasma reactor. Specifically, a heater is provided in the inductively coupled plasma source to facilitate control of the process temperature, thereby improving process reproducibility and reducing a pollution in the reactor. A plasma reactor having an inductively coupled plasma source.

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

Plasma sources for generating plasma are various, and examples thereof include capacitive coupled plasma and inductive coupled plasma using a radio frequency.

Capacitively coupled plasma sources have the advantage that they have higher capacity for process control than other plasma sources because of their accurate capacitive coupling and ion control capability. On the other hand, because the energy of the radio frequency power source is almost exclusively coupled to the plasma through capacitive coupling, the plasma ion density can only be increased or decreased by increasing or decreasing the capacitively coupled radio frequency power. However, an increase in radio frequency power increases the ion impact energy.

On the other hand, the inductively coupled plasma source can easily increase the ion density with the increase of the radio frequency power source, the ion bombardment is relatively low, it is known to be suitable for obtaining a high density plasma. Therefore, inductively coupled plasma sources are commonly used to obtain high density plasma. Inductively coupled plasma sources are typically developed using a radio frequency antenna (RF antenna) and a transformer (also called transformer coupled plasma). The development of technology to improve the characteristics of plasma, and to increase the reproducibility and control ability by adding an electromagnet or a permanent magnet or adding a capacitive coupling electrode.

As a radio frequency antenna, a spiral type antenna or a cylinder type antenna is generally used. The radio frequency antenna is disposed outside the plasma reactor and transmits induced electromotive force into the plasma reactor through a dielectric window such as a ceramic or quartz plate. Inductively coupled plasma using a radio frequency antenna can obtain a high density of plasma relatively easily, but the plasma uniformity is affected by the structural characteristics of the antenna. Therefore, efforts have been made to improve the structure of the radio frequency antenna to obtain a uniform high density plasma.

However, in order to obtain a large plasma, it is limited to widen the antenna or increase the power supplied to the antenna. For example, it is known that a non-uniform plasma is generated in the radiographic state by a standing wave effect. In addition, when high power is applied to the antenna, the capacitive coupling of the radio frequency antenna increases, so that the dielectric window must be thickened, thereby increasing the distance between the radio frequency antenna and the plasma, thereby lowering power transmission efficiency. Losing problems occur. Inductively coupled plasma reactors using a plurality of antennas to obtain a large area plasma have been proposed. However, when using a plurality of antennas, although a large area plasma can be obtained, it is not easy to obtain a uniform plasma.

Recently, in the semiconductor manufacturing industry, due to various factors such as miniaturization of semiconductor devices, enlargement of a silicon wafer substrate for manufacturing a semiconductor circuit, enlargement of a glass substrate for manufacturing a liquid crystal display, and appearance of a new object to be processed, . In particular, there is a need for improved plasma sources and plasma processing techniques that have good processing capabilities for large area workpieces.

On the other hand, the internal temperature of the plasma reactor affects the processing of the substrate to be processed, which requires precise temperature control according to the process characteristics. In addition, since the internal temperature of the plasma reactor is correlated with the internal contamination of the reactor, the control of the internal temperature of the reactor is very important in order to suppress the occurrence of contamination.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma reactor having an inductively coupled plasma source equipped with a heater capable of controlling the temperature inside the plasma reactor so as to increase process reproducibility and reduce internal contamination.

One aspect of the present invention for achieving the above technical problem relates to an inductively coupled plasma reactor. An inductively coupled plasma reactor according to one aspect of the present invention comprises: a reactor body having a plasma induced discharge region; An inductively coupled plasma source for forming an inductively coupled plasma inside the reactor body; A heater electrode installed in the inductively coupled plasma source to control the internal temperature of the reactor body; And a heater driving circuit for supplying power to the heater electrode to control the temperature of the inner region of the reactor body.

In one embodiment, the inductively coupled plasma source comprises: a dielectric window in contact with an inner region of the reactor body and provided with a plurality of gas supply and heater electrodes for gas supply; One or more radio frequency antennas mounted on top of the dielectric window; And a core cover covering the radio frequency antenna such that the magnetic flux entrance orients the inner region of the reactor body.

In one embodiment, the dielectric window includes a trench region in which an antenna is installed, and the heater electrode is provided along the trench region.

In one embodiment, the heater driving circuit comprises: a heater power supply source for supplying a heater operating power; A switch for supplying or cutting off heater operating power to the heater electrode; A temperature sensor for sensing a temperature of the heater; And a heater controller for controlling the operation of the heater power supply and the switch according to the temperature sensed by the temperature sensing sensor.

In one embodiment, the heater driving circuit includes a filter for filtering the noise component of the heater operating power supplied from the heater power supply source to the heater electrode.

According to the plasma reactor having an inductively coupled plasma source provided with a heater of the present invention, the internal temperature of the plasma reactor can be properly and precisely controlled according to the process characteristics, thereby improving process reproducibility, and controlling temperature related to internal contamination. By appropriately carrying out the contamination in the reactor can be reduced to improve the process yield.

For a better understanding of the present invention, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Therefore, the shapes and the like of the elements in the drawings can be exaggeratedly expressed to emphasize a clearer description. It should be noted that in the drawings, the same members are denoted by the same reference numerals. Detailed descriptions of well-known functions and constructions which may be unnecessarily obscured by the gist of the present invention are omitted.

1 is a view showing the main configuration of a plasma reactor according to a preferred embodiment of the present invention. Referring to FIG. 1, a plasma reactor 10 according to a preferred embodiment of the present invention includes a reactor body 12 having a plasma induced discharge region, and a gas supply unit 20 for supplying a process gas into the reactor body 12. ), An inductively coupled plasma source 30 for forming an inductively coupled plasma inside the reactor body 12. The inductively coupled plasma source 30 is provided with a heater electrode 34 for controlling the internal temperature of the reactor body 12. The heater driving circuit 40 supplies power to the heater electrode 34 to control the temperature of the region inside the reactor body 12.

The inside of the reactor body 12 is provided with a substrate support 14 on which the substrate 18 to be processed is placed. The substrate 18 to be processed is, for example, a silicon wafer substrate for manufacturing a semiconductor device or a glass substrate for manufacturing a liquid crystal display, a plasma display or the like. The lower end of the reactor body 12 is provided with a gas outlet 16 for gas exhaust. The gas outlet 16 is connected to a vacuum pump (not shown). Reactor body 12 is constructed from metal materials such as aluminum, stainless steel, and copper. Or coated metal, for example anodized aluminum or nickel plated aluminum. Or refractory metal. Alternatively, it is possible to rewrite the reactor body 12 entirely with an electrically insulating material such as quartz, ceramic, or other materials suitable for carrying out the intended plasma process.

2 is a plan view of a dielectric window constituting the inductively coupled plasma source, and FIG. 3 is a partial cross-sectional view of the dielectric window showing an antenna, a core cover, and a heater electrode installed in the dielectric window. 2 and 3, the inductively coupled plasma source 20 is in contact with an inner region of the reactor body 12 and has a plurality of gas supply holes 35 and a dielectric window provided with a heater electrode 34 for gas supply. 31). One or more radio frequency antennas 32 are installed on top of the dielectric window 31. The core cover 33 is installed on top of the dielectric window 31 such that the magnetic flux entrance orient points to the inner region of the reactor body 12 and covers the radio frequency antenna 32.

The upper portion of the dielectric window 31 has a concave-convex structure that forms a trench region 36 in which one or more radio frequency antennas 32 are installed. The trench region 36 is formed in the same manner as the structure of the radio frequency antenna 32. The structure of the antenna 32 and the trench region 36 may be, for example, a flat spiral structure, but may be modified into other structures for generating a balanced plasma. The plurality of gas supply holes 35 consist of raised portions between the trench regions 35. The radio frequency antennas 32 are each covered by a magnetic core cover 33. The trench region 36 of the dielectric window 32 is covered by a cover member (not shown), which is sealed by a vacuum insulating member such as an O-ring to prevent gas from leaking around the gas supply hole 35. It is preferable. The dielectric window 31 has a flat plate structure as a whole, but may have a domed structure. Alternatively, it may be modified into any other type of structure for uniform generation of plasma.

The core cover 33 is made of ferrite material but may be made of other alternative materials. The core cover 33 is installed so that the vertical cross-sectional structure has a horseshoe shape and is covered along the radio frequency antenna 32 so that the magnetic flux entrance and exit runs inside the reactor body 12. The magnetic flux generated by the radio frequency antenna 32 is thus focused by the magnetic core cover 33 and transferred into the reactor body 12. A more uniform plasma is generated at the top of the reactor body 12 with the function of focusing more strongly than the magnetic flux of the core cover 33.

Referring to FIG. 1, the heater driving circuit 40 senses a heater power supply source 41 for supplying heater operating power, a switch 42 for supplying or blocking a heater operating power to the heater electrode 34, and a temperature of a heater. And a heater controller 45 for controlling the operation of the heater power supply 41 and the switch 42 according to the temperature sensed by the temperature sensor 44. The heater driving circuit 40 may include a filter 43 to filter noise components of the heater operating power supplied from the heater power supply 41 and to apply the same to the heater electrodes.

Referring to FIG. 3, the heater electrode 24 may be installed along both edges of the trench region 36. Alternatively, as shown in FIGS. 4 to 6, the heater electrode 34 may be variously installed at any position of the dielectric window 31 in order to increase the temperature control and the efficiency thereof. For example, as shown in FIG. 4, the gas supply hole 35 of the dielectric window 31 and the trench region 36 may be disposed to be horizontally embedded near the lower portion of the dielectric window 31. Alternatively, as shown in FIG. 5, the structure may be installed to be perpendicular to a portion between the gas supply hole 35 of the dielectric window 31 and the trench region 36. Alternatively, as shown in FIG. 6, a portion covering the entire upper portion of the dielectric window 31 and corresponding to the gas supply hole 35 may be installed to form an opening. In this case, the heater electrode 37 may be preferably wrapped in a cover 37 of a material such as aluminum.

Referring to FIG. 1, a gas supply unit 20 is provided on an inductively coupled plasma source 30. The gas supply unit 20 includes a gas inlet 21 connected to a gas supply source (not shown) and one or more gas distribution plates 22 and through a plurality of gas supply holes 35 at the top of the dielectric window 31. Process gas is input into the reactor body 12. The gas supply unit 20 may be modified to have a separate gas supply structure for separately supplying different process gases supplied from two gas sources when supplying two or more process gases separately may increase process efficiency. .

The radio frequency antenna 32 is electrically connected through an impedance matcher 51 to a power source 50 for supplying radio frequencies. The power supply 50 supplies radio frequency power to the radio frequency antenna 32 through the impedance matcher 51. The power supply 50 may be configured using a radio frequency generator capable of controlling the output power without a separate impedance matcher.

Substrate support 140 is biased with bias power supplied through impedance matcher 54 from one or more bias power sources 52 and 53. Although not shown in the drawings, DC power may be supplied from the DC power supply to the substrate support 14. When bias power is supplied from two or more bias power supplies 52 and 53, each bias power has a different frequency.

FIG. 7 is a diagram showing a single antenna line covered by one core cover, and FIG. 8 is a diagram showing a double antenna line covered by one core cover. As shown in FIG. 7, the radio frequency antenna 32 installed in the trench region 36 is installed as a single line 32 or as two or more parallel lines 32a and 32b as shown in FIG. 8. Can be. Even if one or two or more are installed in parallel can be covered by one core cover 33 as shown in FIG. Of course, when installed in parallel can also be installed independently of the core cover.

Embodiments of the plasma reactor having an inductively coupled plasma source equipped with a heater of the present invention described above are merely exemplary, and various modifications and equivalents from those skilled in the art to which the present invention pertains may be made. It will be appreciated that other embodiments are possible. Accordingly, it is to be understood that the present invention is not limited to the above-described embodiments. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

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

2 is a plan view of a dielectric window constituting an inductively coupled plasma source.

3 is a partial cross-sectional view of a dielectric window showing an antenna, core cover, and heater electrode installed in the dielectric window.

4 through 6 are partial cross-sectional views of dielectric windows showing various modified installation examples of heater electrodes.

7 shows a single antenna covered by one core cover.

8 shows a dual antenna covered by one core cover.

Description of the Related Art [0002]

10: Plasma reactor 12: Reactor body

14: substrate support 16: gas outlet

20: gas supply unit 21: gas distribution plate

30: inductively coupled plasma source 31: dielectric window

32: antenna 33: core cover

34: heater electrode 35: gas supply hole

36: trench area 40: heater drive circuit

41: heater power source 42: switch

43: filter 44: temperature sensor

45: heater controller 50: antenna power source

51: impedance matcher 52, 53: bias power supply

54: impedance matcher

Claims (5)

A reactor body having a plasma induced discharge region; An inductively coupled plasma source for forming an inductively coupled plasma inside the reactor body; A heater electrode installed in the inductively coupled plasma source to control the internal temperature of the reactor body; And In the inductively coupled plasma reactor comprising a heater driving circuit for supplying power to the heater electrode to control the temperature of the inner region of the reactor body, The inductively coupled plasma source is: A dielectric window in contact with an inner region of the reactor body and provided with a plurality of gas supply and heater electrodes for gas supply; One or more radio frequency antennas mounted on top of the dielectric window; And A core cover covering the radio frequency antenna such that the magnetic flux entrance orients the inner region of the reactor body; The dielectric window includes a trench region in which an antenna is installed, and the heater electrode is installed along the trench region. delete delete The method of claim 1, The heater drive circuit is: A heater power supply for supplying heater operating power; A switch for supplying or cutting off heater operating power to the heater electrode; A temperature sensor for sensing a temperature of the heater; And An inductively coupled plasma reactor comprising a heater controller for controlling the operation of the heater power source and the switch in accordance with the temperature sensed by the temperature sensor. 5. The method of claim 4, The heater driving circuit includes a filter for filtering the noise component of the heater operating power supplied from the heater power supply to the heater electrode.

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