KR20130058415A

KR20130058415A - Substrate treating apparatus

Info

Publication number: KR20130058415A
Application number: KR1020110124410A
Authority: KR
Inventors: 김인준
Original assignee: 세메스 주식회사
Priority date: 2011-11-25
Filing date: 2011-11-25
Publication date: 2013-06-04

Abstract

A substrate processing apparatus is disclosed. According to an embodiment of the present invention; A gas supply unit supplying a reaction gas into the process chamber; A chuck positioned inside the process chamber and supporting a substrate; An upper electrode positioned above the chuck to excite the reaction gas; An upper power source electrically connected to the upper electrode; A lower electrode installed at the chuck; A lower power source electrically connected to the lower electrode; And a control unit for controlling the upper power source and the lower power source, wherein the upper power source is provided as a pulse DC power source, and the lower power source includes: a first lower power source for applying high frequency power; A substrate processing apparatus having a second lower power source for applying low frequency power is provided.

Description

[0001] SUBSTRATE TREATING APPARATUS [0002]

The present invention relates to a substrate processing apparatus, and more particularly, to an apparatus for processing a substrate using plasma.

Plasma is generated by very high temperature, strong electric fields or RF Electromagnetic Fields, and refers to an ionized gas state composed of ions, electrons, and radicals. The semiconductor device fabrication process employs a plasma to perform an etching process. The etching process is performed by colliding the ion particles contained in the plasma with the substrate.

1 is a view showing the structure of a conventional substrate processing apparatus.

Referring to FIG. 1, the substrate processing apparatus 1 includes an upper electrode 2, an upper power source 3, a lower electrode 4, and a lower power source 5 and 6. The upper power supply 3 applies high frequency power to the upper electrode 2. The lower power supply 5 applies high frequency power to the lower electrode 4, and the lower power supply 6 applies low frequency power to the lower electrode 4. An etching process for the substrate W is performed between the upper electrode 2 and the lower electrode 4. However, the substrate processing apparatus 1 of FIG. 1 adjusts the plasma density to the power and frequency applied to the lower electrode 4. Therefore, excessive dissociation occurs due to the use of high power and frequency to ensure proper plasma density, thereby lowering the selectivity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate processing apparatus capable of controlling the plasma density by varying the impact ratio.

It is also an object of the present invention to provide a substrate processing apparatus capable of controlling the selectivity reduction phenomenon caused by excessive dissociation of electrons in the plasma.

The objects of the present invention are not limited thereto, and other objects not mentioned may be clearly understood by those skilled in the art from the following description.

According to one aspect of the invention, the process chamber and the space formed therein; A gas supply unit supplying a reaction gas into the process chamber; A chuck positioned inside the process chamber and supporting a substrate; An upper electrode positioned above the chuck to excite the reaction gas; An upper power source electrically connected to the upper electrode; A lower electrode installed at the chuck; A lower power source electrically connected to the lower electrode; And a control unit for controlling the upper power source and the lower power source, wherein the upper power source is provided as a pulse DC power source, and the lower power source includes: a first lower power source for applying high frequency power; A substrate processing apparatus having a second lower power source for applying low frequency power may be provided.

In addition, the pulse DC power supply is a substrate processing apparatus provided with any one of a negative pulse DC power supply, a positive pulse DC power supply, and a rectangular pulse DC power supply. May be provided.

The controller may be provided with a substrate processing apparatus that variably controls a pulse frequency and / or a duty ratio of the pulse DC power.

In addition, a substrate processing apparatus may be provided in which a variable range of the pulse frequency is provided at a frequency of 1 Hz to 99 MHz, and a variable range of the impact ratio is provided at 10% to 90%.

The first lower power source includes a first high frequency lower power source and a second high frequency lower power source, and the control unit controls the first high frequency lower power source to have a frequency of 60 MHz to 200 MHz, and the second high frequency lower power source. A substrate processing apparatus may be provided to control a power supply to have a frequency of 13.56 MHz to 40 MHz, and to control the second lower power supply to have a frequency of 1 kHz to 2 MHz.

According to an embodiment of the present invention, the plasma density may be secured by applying a pulsed direct current to the upper electrode and varying the frequency and the duty ratio.

In addition, according to the embodiment of the present invention, it is possible to prevent the selectivity decrease phenomenon caused by excessive dissociation of electrons in the plasma.

1 is a view showing the structure of a conventional substrate processing apparatus.
2 is a cross-sectional view showing a substrate processing apparatus according to an embodiment of the present invention.
3 to 5 are graphs showing the frequency and the duty ratio of the pulse DC power applied to the first upper power.

Hereinafter, a substrate processing apparatus according to an exemplary embodiment will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 is a cross-sectional view showing a substrate processing apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the substrate processing apparatus 10 generates a plasma to process the substrate W. Referring to FIG. The substrate processing apparatus 10 includes a process chamber 100, a chuck 200, a gas supply unit 300, a plasma generator 400, a heating unit 500, and a controller 600.

The process chamber 100 has a space 101 formed therein. The internal space 101 is provided as a space for performing a plasma processing process on the substrate (W). Plasma treatment for the substrate W includes an etching process. An exhaust hole 102 is formed in the bottom surface of the process chamber 100. The exhaust hole 102 is connected to the exhaust line 121. Reaction by-products generated during the process and the gas remaining in the process chamber 100 may be discharged to the outside through the exhaust line 121. The internal space 101 of the process chamber 100 is decompressed to a predetermined pressure by the exhaust process.

The chuck 200 is located inside the process chamber 100. The chuck 200 supports the substrate W. The chuck 200 includes an electrostatic chuck that sucks and fixes the substrate W by using electrostatic force. The chuck 200 includes a dielectric plate 210, a lower electrode 220, a heater 230, a support plate 240, and an insulating plate 270.

The dielectric plate 210 is located at the upper end of the chuck 200. The dielectric plate 210 is provided as a dielectric substance. A substrate W is placed on the upper surface of the dielectric plate 210. The upper surface of the dielectric plate 210 has a smaller radius than the substrate W. [ Therefore, the edge region of the substrate W is located outside the dielectric plate 210. The first supply channel 211 is formed in the dielectric plate 210. The first supply passage 211 is provided from the top surface of the dielectric plate 210 to the bottom surface. A plurality of first supply passages 211 are formed to be spaced apart from each other, and are provided as a passage through which a heat transfer medium is supplied to the bottom surface of the substrate W.

A lower electrode 220 and a heater 230 are buried in the dielectric plate 210. The lower electrode 220 is located on the upper portion of the heater 230. The lower electrode 220 is connected to the lower power supply 221. The lower power supply unit 221 applies power to the lower electrode 220. The lower power supply unit 221 includes three lower power sources 222, 223, and 224 and a matching unit 225. The controller 600 controls the first to third lower power sources 222, 223, and 224 to generate frequency power of different magnitudes. The first to second lower power sources 222 and 223 may be provided as high frequency power sources, and the third lower power source 224 may be provided as low frequency power sources. In an embodiment, the first lower power source 222 may generate frequency power of 60 MHz to 200 MHz, the second lower power source 223 may generate frequency power of 13.56 MHz to 40 MHz, and the third lower power source ( 224 may generate frequency power between 1 KHz and 2 MHz. In some exemplary embodiments, only one first lower power source 222 and one second lower power source 223 may be provided. The matching unit 225 is electrically connected to the first to third lower power sources 222, 223, and 224, and applies frequency powers of different magnitudes to the lower electrode 220. An electric force acts between the lower electrode 220 and the substrate W by the power applied to the lower electrode 220, and the substrate W is absorbed by the dielectric plate 210 by the electric force.

The heater 230 is electrically connected to an external power source (not shown). The heater 230 generates heat by resisting a current applied from an external power source. The generated heat is transferred to the substrate W through the dielectric plate 210. The substrate W is maintained at a predetermined temperature by the heat generated in the heater 230. The heater 230 includes a helical coil. The heaters 230 may be embedded in the dielectric plate 210 at regular intervals.

The support plate 240 is positioned below the dielectric plate 210. The bottom surface of the dielectric plate 210 and the top surface of the support plate 240 may be bonded by the adhesive 236. The support plate 240 may be provided of aluminum material. The upper surface of the support plate 240 may be stepped so that the center region is positioned higher than the edge region. The top center region of the support plate 240 has an area corresponding to the bottom of the dielectric plate 210 and is bonded to the bottom of the dielectric plate 210. The support plate 240 is provided with a first circulation passage 241, a second circulation passage 242, and a second supply passage 243.

The first circulation passage 241 is provided as a passage through which the heat transfer medium circulates. The first circulation channel 241 may be formed in a spiral shape in the support plate 240. Alternatively, the first circulation channel 241 may be arranged such that ring-shaped channels having different radii have the same center. Each of the first circulation passages 241 may communicate with each other. The first circulation passages 241 are formed at the same height.

The second circulation passage 242 is provided as a passage through which the cooling fluid circulates. The second circulation channel 242 may be formed in a spiral shape in the support plate 240. Alternatively, the second circulation channel 242 may be arranged such that ring-shaped channels having different radii have the same center. Each of the second circulation passages 242 may communicate with each other. The second circulation channel 242 may have a larger cross-sectional area than the first circulation channel 241. The second circulation passages 242 are formed at the same height. The second circulation channel 242 may be located below the first circulation channel 241.

The second supply flow passage 243 extends upward from the first circulation flow passage 241 and is provided on an upper surface of the support plate 240. The second supply flow path 243 is provided in a number corresponding to the first supply flow path 211, and connects the first circulation flow path 241 and the first supply flow path 211.

The first circulation passage 241 is connected to the heat transfer medium storage unit 252 through the heat transfer medium supply line 251. The heat transfer medium storage unit 252 stores the heat transfer medium. The heat transfer medium includes an inert gas. According to an embodiment, the heat transfer medium comprises helium (He) gas. The helium gas is supplied to the first circulation channel 241 through the supply line 251, and is sequentially supplied to the bottom surface of the substrate W through the second supply channel 243 and the first supply channel 211. The helium gas serves as a medium through which heat transferred from the plasma to the substrate W is transferred to the chuck 200. The ion particles contained in the plasma are attracted to the electric force formed in the chuck 200, move to the chuck 200, and collide with the substrate W to perform an etching process. Heat is generated in the substrate W while the ion particles collide with the substrate W. Heat generated in the substrate W is transferred to the chuck 200 through the helium gas supplied to the space between the bottom surface of the substrate W and the top surface of the dielectric plate 210. As a result, the substrate W can be maintained at a set temperature.

The second circulation channel 242 is connected to the cooling fluid storage unit 262 through the cooling fluid supply line 261. The cooling fluid is stored in the cooling fluid storage unit 262. The cooler 263 may be provided in the cooling fluid reservoir 262. The cooler 263 cools the cooling fluid to a predetermined temperature. Alternatively, cooler 263 may be installed on cooling fluid supply line 261. The cooling fluid supplied to the second circulation passage 242 through the cooling fluid supply line 261 circulates along the second circulation passage 242 and cools the support plate 240. Cooling of the support plate 240 cools the dielectric plate 210 and the substrate W together to maintain the substrate W at a predetermined temperature.

An insulating plate 270 is provided below the support plate 240. The insulating plate 270 is provided in a size corresponding to the support plate 240. The insulating plate 270 is positioned between the support plate 240 and the bottom surface of the chamber 100. The insulating plate 270 is provided with an insulating material and electrically insulates the support plate 240 and the chamber 100.

The focus ring 280 is disposed in an edge region of the chuck 200. The focus ring 200 has a ring shape and is disposed along a circumference of the dielectric plate 210. The upper surface of the focus ring 280 may be stepped so that the outer portion 280a is higher than the inner portion 280b. The upper inner side portion 280b of the focus ring 280 is positioned at the same height as the upper surface of the dielectric plate 210. An upper inner portion 280b of the focus ring 280 supports an edge region of the substrate W positioned outside the dielectric plate 210. The outer portion 280a of the focus ring 280 is provided to surround the substrate W edge region. The focus ring 280 extends the electric field forming region so that the substrate W is located at the center of the region where the plasma is formed. Thereby, plasma is uniformly formed over the entire region of the substrate W, so that each region of the substrate W can be uniformly etched.

The gas supply part 300 supplies the process gas to the process chamber 100. The gas supply unit 300 includes a gas storage unit 310, a gas supply line 320, and a gas inflow port 330. The gas supply line 320 connects the gas storage unit 310 and the gas inlet port 330, and supplies the process gas stored in the gas storage unit 310 to the gas inlet port 330. The gas inlet port 330 is connected to the gas supply holes 412 formed in the upper electrode 410.

The plasma generator 400 excites the process gas staying inside the process chamber 100. The plasma generator 400 includes an upper electrode 410, a distribution plate 420, and an upper power supply unit 440.

The upper electrode 410 is provided in a disc shape and is positioned above the chuck 200. The upper electrode 410 includes an upper plate 410a and a lower plate 410b. The upper plate 410a is provided in a disc shape. The top plate 410a is electrically connected to the first upper power source 441. The upper plate 410a applies the high frequency power generated by the first upper power source 441 to the process gas remaining in the process chamber 100 to excite the process gas. The process gas is excited and converted into a plasma state. The bottom of the top plate 410a is stepped so that the center region is located higher than the edge region. Gas supply holes 412 are formed in the central region of the upper plate 410a. The gas supply holes 412 are connected to the gas inlet port 330 and supply process gas to the buffer space 414. The cooling passage 411 may be formed in the upper plate 410a. The cooling passage 411 may be formed in a spiral shape. Alternatively, the cooling flow passage 411 may be arranged such that ring-shaped flow passages having different radii have the same center. The cooling passage 411 is connected to the cooling fluid storage 432 through the cooling fluid supply line 431. The cooling fluid reservoir 432 stores the cooling fluid. The cooling fluid stored in the cooling fluid storage 432 is supplied to the cooling passage 411 through the cooling fluid supply line 431. The cooling fluid circulates through the cooling passage 411 and cools the upper plate 410a.

The lower plate 410b is located below the upper plate 410a. The lower plate 410b is provided in a size corresponding to the upper plate 410a and is positioned to face the upper plate 410a. The upper surface of the lower plate 410b is stepped so that the center region is located lower than the edge region. The upper surface of the lower plate 410b and the bottom surface of the upper plate 410a are combined with each other to form a buffer space 414. The buffer space 414 is provided as a space where the gas supplied through the gas supply holes 412 temporarily stays before being supplied into the process chamber 100. Gas supply holes 413 are formed in the central region of the lower plate 410b. The gas supply holes 413 are spaced apart at regular intervals and are formed in plurality. The gas supply holes 413 are connected to the buffer space 414.

The distribution plate 420 is located below the lower plate 410b. The distribution plate 420 is provided in a disc shape. Distribution holes 421 are formed in the distribution plate 420. The distribution holes 421 are provided from the upper surface of the distribution plate 420 to the lower surface. The distribution holes 421 are provided in a number corresponding to the gas supply holes 413 and are positioned corresponding to the points where the gas supply holes 413 are located. The process gas staying in the buffer space 414 is uniformly supplied into the process chamber 100 through the gas supply hole 413 and the distribution holes 421.

The upper power supply unit 440 applies high frequency power to the upper plate 410a. The power supply unit 440 includes a first upper power source 441 and a filter 442. The first upper power source 441 is electrically connected to the top plate 410a. The first upper power source 441 is provided as a pulsed DC power source.

3 to 5 are graphs showing a frequency and an impact coefficient of a pulse DC power source applied to the first upper power source of FIG. 2.

3 to 5, the first upper power supply 441 may be any one of a negative pulse DC power supply, a positive pulse DC power supply, or a rectangular pulse DC power supply. Can be provided. The pulse frequency and / or duty ratio of the first upper power source 441 are variably provided. In an embodiment, the variable range of the pulse frequency may be provided at a frequency of 1 Hz to 99 MHz, and the variable range of the duty ratio may be provided at 10% to 90%. On the other hand, when the first upper power source 441 is provided as a negative pulse DC power supply, the ion bombardment of the upper electrode 410 is increased, and the secondary electrons generated by the secondary electrons help maintain plasma density. Unlike the technique, the plasma density may be controlled through the variation of the duty ratio. In addition, when the first upper power supply 441 is provided as a positive pulse DC power supply, the excessive dissociation of electrons that are excessively dissociated in the plasma according to the use of high frequency and power at the lower electrode 220 may be caused by excessive dissociation. Selectivity reduction phenomenon can be controlled. In addition, when the first upper power source 441 is provided as a rectangular pulse DC power source, the above-described control conditions may be combined and applied. On the other hand, in the case of a rectangular pulse DC power supply, a positive DC voltage and a negative DC voltage may be applied to different values.

Referring back to FIG. 2, the filter 442 is electrically connected to the first upper power source 441 and the upper plate 410a in a section between the first upper power source 441 and the upper plate 410a. The filter 442 passes the first frequency power so that the first frequency power generated by the first upper power source 441 is applied to the upper plate 410a. The filter 442 blocks the second frequency power applied to the heater 510 from being transmitted to the first upper power source 441. Filter 442 includes a high-pass filter.

The heating unit 500 heats the lower plate 410b. The heating unit 500 includes a heater 510, a second upper power source 520, and a filter 530. The heater 510 is installed inside the lower plate 410b. The heater 510 may be provided in an edge region of the lower plate 410b. The heater 510 may include a heating coil and may be provided to surround a central area of the lower plate 410b. The second upper power source 520 is electrically connected to the heater 510. The second upper power source 520 generates a second frequency power. The second frequency power is different from the first frequency power. The second frequency power may be provided at a frequency lower than the first frequency power. The second frequency power may have a 60 Hz frequency. The second upper power source 520 may generate DC power. Alternatively, the second upper power source 520 may generate AC power. The second frequency power generated by the second upper power source 520 is applied to the heater 510, and the heater 510 generates heat by resisting the applied current. The heat generated by the heater 510 heats the lower plate 410b, and the heated lower plate 410b heats the distribution plate 420 positioned below it to a predetermined temperature. The lower plate 420 may be heated to a temperature of 60 ℃ ~ 300 ℃.

The filter 530 is electrically connected to the second upper power source 520 and the heater 510 in a section between the second upper power source 520 and the heater 510. The filter 530 passes the second frequency power so that the second frequency power generated by the second upper power source 520 is applied to the heater 510. The filter 530 blocks the first frequency power applied to the upper plate 410a from being transmitted to the second upper power source 520. The filter 530 includes a low-pass filter.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.

Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

** Explanation of symbols on the main parts of the drawing **
100: process chamber 200: chuck
300: gas supply unit 400: plasma generation unit
500: heating unit 600: control unit

Claims

A process chamber having a space formed therein;
A gas supply unit supplying a reaction gas into the process chamber;
A chuck positioned inside the process chamber and supporting a substrate;
An upper electrode positioned above the chuck to excite the reaction gas;
An upper power source electrically connected to the upper electrode;
A lower electrode installed at the chuck;
A lower power source electrically connected to the lower electrode;
A control unit for controlling the upper power and the lower power,
The upper power source is provided as a pulse DC power source,
The lower power source,
A first lower power source for applying high frequency power;
A substrate processing apparatus having a second lower power source for applying low frequency power.

The method of claim 1,
The pulse DC power supply may be provided as any one of a negative pulse DC power supply, a positive pulse DC power supply, and a rectangular pulse DC power supply.