Substrate processing device and impedance matching method

Abstract

Disclosed is an apparatus for processing a substrate. The apparatus includes: an RF power supply; a processing chamber that performs plasma processing using power applied from the RF power supply; and an impedance matching unit disposed between the RF power supply and the processing chamber and performing impedance matching. The RF power supply includes a first sensor that measures impedance in a direction between the processing chamber and the impedance matching unit, and the impedance matching unit performs impedance matching by reflecting the impedance measured by the first sensor in the RF power supply.

Description

Technical Field

[0001] The invention relates to a substrate processing device and an impedance matching method. Background Art

[0002] In recent plasma etching processes, plasma control using multiple RF frequencies is commonly used. After the chamber is vacuumed, gases are introduced and an RF voltage is applied, accelerating electrons to form a plasma. During this process, an impedance matching unit must be located between the chamber and the RF power source to ensure maximum power delivery to the chamber.

[0003] In the impedance matching principle of the impedance matching unit, the impedance (Z L The impedance (t) = R + jX) is measured by a sensor located at the output side of the impedance matching unit, and the internal circuit is controlled to make the measured impedance the same as the impedance at the input. Typically, to minimize impedance changes between the impedance matching unit and the processing chamber, the impedance matching unit and the processing chamber can be attached to each other. In addition, to reduce the impact of interference between the RF power supply and the impedance matching unit, a cable corresponding to half the wavelength of the RF frequency (approximately tens of meters) can be selected and connected.

[0004] The structure of the existing substrate processing device is as follows Figure 3 shown.

[0005] However, the conventional substrate processing apparatus has the following problems.

[0006] Cables are not manufactured to match the half-wavelength of the RF power source's RF frequency, leading to matching errors. Therefore, when using commercially available cables, additional correction for impedance deviations is required. Furthermore, when setting up the equipment, there may be problems with the cable layout changing depending on the location and space, or the cable bending during installation. In particular, when the cable layout changes or the cable bends, the inductance changes depending on the cable's shape. This makes it virtually impossible to evaluate and test substrate processing equipment during the product release phase.

[0007] That is, in Figure 3 In the structure of the conventional substrate processing apparatus shown in FIG, even if the maximum power transmission condition Z is satisfied by impedance matching in the impedance matching unit and the processing chamber end, the maximum power transmission condition Z G =Z m , considering the total impedance of the cable impedance of about tens of meters is Z T (x, t) = 50 + Z c (x)≠Z G, causing power reflections in the direction of the RF power source. Furthermore, with recent advances in etching technology, the required RF power has reached tens of kilowatts, further increasing the impact of interference from cables. This interference can lead to serious consequences, such as reduced etching efficiency and operational errors in the RF power source.

[0008] Therefore, in the related art, when impedance matching is performed by focusing only on impedance matching between the impedance matching unit and the process chamber, there is a problem that the actual total impedance Z observed from the RF power supply is T Does not meet the maximum power transmission condition Z G =Z T . Summary of the Invention

[0009] The present invention is directed to providing an apparatus and method capable of more accurately matching impedance than the related art.

[0010] The problems to be solved by the present invention are not limited to the above-mentioned problems. Those skilled in the art will clearly understand unmentioned problems through the following description.

[0011] Example embodiments of the present invention provide an apparatus for processing a substrate.

[0012] The apparatus includes: an RF power supply; a processing chamber that performs plasma processing by using power applied from the RF power supply; and an impedance matching unit that is provided between the RF power supply and the processing chamber and performs matching, wherein the RF power supply includes a first sensor that measures impedance in a direction of the processing chamber and the impedance matching unit, and the impedance matching unit performs impedance matching by reflecting the impedance measured by the first sensor in the RF power supply.

[0013] According to example embodiments, the impedance matching unit may include a second sensor measuring impedance in a direction of the process chamber.

[0014] According to an exemplary embodiment, the impedance matching unit may include a third sensor measuring impedance in the direction of the RF power source.

[0015] According to an exemplary embodiment, the impedance matching unit may perform primary impedance matching by using a value measured by the second sensor, and perform secondary impedance matching to correct a difference by using a value measured by the first sensor.

[0016] According to an exemplary embodiment, the impedance matching unit may perform primary impedance matching by using a value measured by the second sensor, and correct a difference by using a value measured by the first sensor and a value measured by the third sensor.

[0017] According to an exemplary embodiment, the impedance matching unit may perform the impedance matching within a range that satisfies a maximum power transmission condition.

[0018] According to example embodiments, the RF power source may be provided in plurality, and the impedance matching unit may perform the matching between the plurality of RF power sources and the process chamber.

[0019] Another exemplary embodiment of the present invention provides an apparatus for processing a substrate.

[0020] The apparatus includes: an RF power source; a processing chamber that performs plasma processing by using power applied by the RF power source; and an impedance matching unit that is provided between the RF power source and the processing chamber and performs matching, wherein the impedance matching unit includes a second sensor that measures impedance in a direction of the processing chamber and a third sensor that measures impedance in a direction of the RF power source.

[0021] According to an exemplary embodiment, the impedance matching unit may perform primary impedance matching by using a value measured by the second sensor, and perform secondary impedance matching by using a value measured by the third sensor.

[0022] According to an exemplary embodiment, the impedance matching unit may calculate the impedance of the cable by considering the value measured by the third sensor and a previously measured impedance of the RF power source.

[0023] According to an exemplary embodiment, the secondary impedance matching may be performed by considering the impedance of the cable.

[0024] According to an exemplary embodiment, the impedance matching unit may perform the impedance matching within a range that satisfies a maximum power transmission condition.

[0025] According to example embodiments, the RF power source may be provided in plurality, and the impedance matching unit performs the matching between the plurality of RF power sources and the process chamber.

[0026] Another exemplary embodiment of the present invention provides a method of performing impedance matching through an impedance matching unit connected between an RF power source and a process chamber in a substrate processing apparatus that performs plasma processing in the process chamber by using power applied from the RF power source.

[0027] The method may include: measuring the impedance of the process chamber side by the impedance matching unit; performing primary impedance matching by using the impedance of the process chamber side; and performing secondary impedance matching by using an additional measured impedance value.

[0028] According to an exemplary embodiment, performing the secondary impedance matching by using the additionally measured impedance value may include measuring an impedance value observed from the RF power source.

[0029] According to an exemplary embodiment, performing the secondary impedance matching by using the additionally measured impedance value may include performing the impedance matching to correct a difference between the impedance value observed from the RF power source and a resultant value of the primary impedance matching.

[0030] According to an exemplary embodiment, performing the secondary impedance matching by using the additionally measured impedance value may include measuring an impedance value facing the RF power source by the impedance matching unit.

[0031] According to an exemplary embodiment, the method may further include calculating, by the impedance matching unit, an impedance of a cable connecting the impedance matching unit and the RF power source by using the impedance value facing the RF power source and a previously measured impedance of the RF power source.

[0032] According to an exemplary embodiment, the impedance matching may be performed by considering an impedance value of the cable.

[0033] According to an exemplary embodiment, the impedance matching unit may perform the impedance matching within a range that satisfies a maximum power transmission condition.

[0034] According to the present invention, compared with the prior art, it is possible to more accurately match impedance.

[0035] The effects of the present invention are not limited to the above-mentioned effects, and those skilled in the art can clearly understand the effects not mentioned from this specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1A and Figure 1B The figure shows a schematic configuration of a chamber according to an exemplary embodiment of the present invention.

[0037] Figure 2 The drawing illustrates a configuration of a substrate processing apparatus according to an exemplary embodiment of the present invention.

[0038] Figure 3 is a block diagram illustrating a substrate processing apparatus in the related art.

[0039] Figure 4is a block diagram illustrating a substrate processing apparatus according to a first exemplary embodiment of the present invention.

[0040] Figure 5 is a block diagram illustrating a substrate processing apparatus according to a second exemplary embodiment of the present invention.

[0041] Figure 6 is a block diagram illustrating a substrate processing apparatus according to a third exemplary embodiment of the present invention.

[0042] Figure 7 The diagram illustrates impedance matching performed by the substrate processing apparatus according to the first exemplary embodiment of the present invention.

[0043] Figure 8 The diagram illustrates impedance matching performed by a substrate processing apparatus according to a third exemplary embodiment of the present invention.

[0044] Figure 9 is a flowchart illustrating an impedance matching method according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0045] Hereinafter, exemplary embodiments of the present invention will be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the present invention are shown. However, the present invention may be implemented differently and is not limited to the following embodiments. In the following description of the present invention, detailed descriptions of known functions and configurations incorporated herein are omitted to avoid making the subject matter of the present invention unclear. In addition, for components with similar functions and effects, the same reference numerals are used throughout the drawings.

[0046] Unless explicitly described to the contrary, the word "include" and variations such as "comprising" will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements. It should be understood that the terms "include" and "have" are intended to indicate the presence of the features, numbers, steps, operations, constituent elements and parts, or a combination thereof, described in the specification, and do not exclude the possibility of the pre-existence or addition of one or more other features, numbers, steps, operations, constituent elements and parts, or a combination thereof.

[0047] Singular expressions used herein include plural expressions unless they have clearly opposite meanings in the context. Therefore, the shapes, sizes, etc. of elements in the drawings may be exaggerated for clearer description.

[0048] Figure 1A and Figure 1B The figure shows a schematic configuration of a chamber according to an exemplary embodiment of the present invention.

[0049] like Figure 1A and Figure 1BAs shown, the plasma chamber 100 may include electrodes 110a and 110b to which RF signals are applied. The electrodes 110a and 110b may transmit electrical energy to the chamber so that gas introduced into the chamber is ionized and changes into a plasma state. Figure 1A The electrodes 110a and 110b shown in FIG are examples of a capacitively coupled plasma (CCP) source in which two electrode plates are arranged to face each other inside a chamber. The CCP source can transfer electrical energy to electrons of a gas introduced into the chamber by utilizing a capacitor electric field. The CCP source can have a form in which each of the two electrode plates is connected to an RF power source, but according to an exemplary embodiment, the RF power source can also be connected only to the upper electrode plate between the two electrode plates. Figure 1B The illustrated electrode 110c represents an example of an inductively coupled plasma (ICP) formed by an induction coil wound around the outside of the plasma chamber 100. In an ICP source, a plasma generating device is separately coupled to the upper portion of the chamber to change a gas introduced into the chamber into a plasma state and to supply the plasma to the chamber in a downstream process.

[0050] Figure 2 The drawing illustrates a configuration of a substrate processing apparatus according to an exemplary embodiment of the present invention. Figure 2 An example of a case where a CCP source is used in the exemplary embodiment of FIG. 1 is shown.

[0051] refer to Figure 2 The substrate processing apparatus 10 processes the substrate W by using plasma. For example, the substrate processing apparatus 10 may perform an etching process on the substrate W. The substrate processing apparatus 10 may include a plasma chamber 100, a substrate supporting unit 200, a gas supply unit 300, a plasma generating unit 400, and a heating unit 500.

[0052] The plasma chamber 100 has a space 101 formed therein. The interior space 101 is provided as a space in which a plasma process is performed on a substrate W. The plasma process on the substrate W includes an etching process. An exhaust hole 102 is formed in the bottom surface of the plasma chamber 100. The exhaust hole 102 is connected to an exhaust line 121. Reaction byproducts generated during the process and gases remaining inside the plasma chamber 100 can be discharged to the outside through the exhaust line 121. Through the exhaust process, the interior space 101 of the plasma chamber 100 is depressurized to a predetermined pressure.

[0053] The substrate support unit 200 is located inside the plasma chamber 100. The substrate support unit 200 supports the substrate W. The substrate support unit 200 includes an electrostatic chuck that absorbs and fixes the substrate W by using an electrostatic force. The substrate support unit 200 may include a dielectric plate 210, a lower electrode 220, a heater 230, a support plate 240, and an insulating plate 270.

[0054] The dielectric plate 210 is located at the upper end of the substrate support unit 200. The dielectric plate 210 is configured as a disk-shaped dielectric. A substrate W can be placed on the upper surface of the dielectric plate 210. The radius of the upper surface of the dielectric plate 210 is smaller than the radius of the substrate W. Therefore, the edge region of the substrate W is located outside the dielectric plate 210. A first supply flow path 211 is formed in the dielectric plate 210. The first supply flow path 211 is configured to lead from the upper surface of the dielectric plate 210 to the lower surface of the dielectric plate 210. Multiple first supply flow paths 211 are formed to be spaced apart from each other and provide channels for supplying heat transfer medium to the bottom surface of the substrate W. Separate electrodes for attracting the substrate W to the dielectric plate 210 can be embedded in the dielectric plate 210. Direct current can be applied to the electrodes. The applied current causes electrostatic force to act between the electrodes and the substrate, and the substrate W can be attracted to the dielectric plate 210 by the electrostatic force.

[0055] The lower electrode 220 is connected to a lower power supply unit 221. The lower power supply unit 221 supplies power to the lower electrode 220. The lower power supply unit 221 includes lower RF power supplies 222 and 223 and a lower impedance matching unit 225. As shown in FIG1 , multiple lower RF power supplies 222 and 223 may be provided. Alternatively, only one lower RF power supply may be provided. The lower RF power supplies 222 and 223 may adjust the plasma density. The lower RF power supplies 222 and 223 primarily adjust the ion bombardment energy. The lower RF power supplies 222 and 223 may generate frequency power of 2 MHz and 13.56 Hz, respectively. The lower impedance matching unit 225 is electrically connected to the lower RF power supplies 222 and 223, matches frequency power of different magnitudes, and applies the matched frequency power to the lower electrode 220.

[0056] The heater 230 is electrically connected to an external power source (not shown). The heater 230 generates heat by resisting current applied from the external power source. The generated heat is transferred to the substrate W through the dielectric plate 210. The heat generated by the heater 230 maintains the substrate W at a predetermined temperature. The heater 230 includes a spiral coil. The heaters 230 may be embedded in the dielectric plate 210 at regular intervals.

[0057] Support plate 240 is positioned below dielectric plate 210. The bottom surface of dielectric plate 210 and the top surface of support plate 240 may be bonded together by adhesive 236. Support plate 240 may be made of aluminum. The top surface of support plate 240 may be stepped, with the center region being higher than the edge regions. The center region of the top surface of support plate 240 has an area corresponding to the bottom surface of dielectric plate 210 and is bonded to the bottom surface of dielectric plate 210. A first circulation flow path 241, a second circulation flow path 242, and a second supply flow path 243 are formed in support plate 240.

[0058] The first circulation flow path 241 is provided as a channel for the heat transfer medium to circulate therein. The first circulation flow path 241 may be formed in a spiral shape within the support plate 240. In addition, the first circulation flow path 241 may be arranged so that annular flow paths with different radii have the same center. The first circulation flow paths 241 may be interconnected. The first circulation flow paths 241 are formed at the same height.

[0059] The second circulation flow path 242 is provided as a channel for circulating the cooling fluid. The second circulation flow path 242 may be formed in a spiral shape inside the support plate 240. In addition, the second circulation flow paths 242 may be arranged so that annular flow paths with different radii have the same center. Each second circulation flow path 242 may be connected to each other. The second circulation flow path 242 may have a larger cross-sectional area than the cross-sectional area of ​​the first circulation flow path 241. The second circulation flow paths 242 are formed at the same height. The second circulation flow path 242 may be located below the first circulation flow path 241.

[0060] Second supply paths 243 extend upward from first circulation paths 241 and are disposed to lead to the upper surface of support plate 240. Second supply paths 243 are provided in the same number as first supply paths 211 and connect first circulation paths 241 and first supply paths 211.

[0061] The first circulation flow path 241 is connected to the heat transfer medium storage unit 252 via a heat transfer medium supply line 251. A heat transfer medium is stored in the heat transfer medium storage unit 252. The heat transfer medium includes an inert gas. According to an exemplary embodiment, the heat transfer medium includes helium (He) gas. Helium gas is supplied to the first circulation flow path 241 via the supply line 251, and then sequentially supplied to the bottom surface of the substrate W via the second supply flow path 243 and the first supply flow path 211. The helium gas serves as a medium for transferring heat transferred from the plasma to the substrate W to the substrate support unit 200. Ion particles contained in the plasma are attracted by the electric force generated in the substrate support unit 200 and move to the substrate support unit 200. During this movement, the ion particles collide with the substrate W, performing the etching process. Heat is generated in the substrate W during the collision of the ion particles with the substrate W. The heat generated in the substrate W is transferred to the substrate support unit 200 via the helium gas supplied to the space between the bottom surface of the substrate W and the upper surface of the dielectric plate 210. As a result, the substrate W can be maintained at a set temperature.

[0062] The second circulation flow path 242 is connected to a cooling fluid storage unit 262 via a cooling fluid supply line 261. The cooling fluid is stored in the cooling fluid storage unit 262. A cooler 263 may be provided within the cooling fluid storage unit 262. The cooler 263 cools the cooling fluid to a predetermined temperature. Conversely, the cooler 263 may be mounted on the cooling fluid supply line 261. The cooling fluid supplied to the second circulation flow path 242 via the cooling fluid supply line 261 cools the support plate 240 while circulating along the second circulation flow path 242. The cooling of the support plate 240 cools both the dielectric plate 210 and the substrate W, thereby maintaining the substrate W at a predetermined temperature.

[0063] The insulating plate 270 is provided below the support plate 240. The insulating plate 270 is provided with a size corresponding to the size of the support plate 240. The insulating plate 270 is located between the support plate 240 and the bottom surface of the plasma chamber 100. The insulating plate 270 is made of an insulating material and electrically insulates the support plate 240 from the plasma chamber 100.

[0064] An edge ring 280 is provided in the edge region of the substrate support unit 200. The edge ring 280 has a ring shape and is provided along the circumference of the dielectric plate 210. The upper surface of the edge ring 280 may be stepped, with the outer portion 280a being higher than the inner portion 280b. The inner portion 280b of the upper surface of the edge ring 280 is at the same height as the upper surface of the dielectric plate 210. The inner portion 280b of the upper surface of the edge ring 280 supports the edge region of the substrate W located outside the dielectric plate 210. The outer portion 280a of the edge ring 280 is provided to surround the edge region of the substrate W. The edge ring 280 expands the electric field formation region, positioning the substrate W at the center of the plasma formation region. Consequently, plasma is uniformly formed across the entire area of ​​the substrate W, enabling uniform etching of each region of the substrate W.

[0065] The gas supply unit 300 supplies process gas to the plasma chamber 100. The gas supply unit 300 includes a gas storage unit 310, a gas supply line 320, and a gas inlet 330. The gas supply line 320 connects the gas storage unit 310 and the gas inlet 330 and supplies the process gas stored in the gas storage unit 310 to the gas inlet 330. The gas inlet 330 is connected to a gas supply hole 412 formed in the upper electrode 410.

[0066] The plasma generating unit 400 excites the traveling gas staying in the plasma chamber 100. The plasma generating unit 400 includes an upper electrode 410, a distribution plate 420, and an upper power supply unit 440.

[0067] The upper electrode 410 is configured in a disk shape and is located above the substrate support unit 200. The upper electrode 410 includes an upper plate 410a and a lower plate 410b. The upper plate 410a is configured in a disk shape. The upper plate 410a is electrically connected to an upper RF power source 441. The upper plate 410a applies the first RF power generated by the upper RF power source 441 to the process gas residing in the plasma chamber 100 to excite the process gas. The process gas is excited and converted into a plasma state. The bottom surface of the upper plate 410a is stepped, with the center area being higher than the edge areas. A gas supply hole 412 is formed in the center area of ​​the upper plate 410a. The gas supply hole 412 is connected to the gas inlet 330 and supplies the process gas to the buffer space 414. A cooling flow path 411 may be formed within the upper plate 410a. The cooling flow path 411 may be formed in a spiral shape. Alternatively, the cooling flow path 411 may be arranged so that annular flow paths with different radii have the same center. The cooling flow path 411 is connected to the cooling fluid storage unit 432 via a cooling fluid supply line 431. The cooling fluid storage unit 432 stores cooling fluid. The cooling fluid stored in the cooling fluid storage unit 432 is supplied to the cooling flow path 411 via the cooling fluid supply line 431. The cooling fluid circulates in the cooling flow path 411 and cools the upper plate 410a.

[0068] The lower plate 410b is located below the upper plate 410a. The lower plate 410b is configured to have a size corresponding to that of the upper plate 410a and is positioned facing the upper plate 410a. The upper surface of the lower plate 410b is stepped so that the central area is lower than the edge area. The upper surface of the lower plate 410b and the bottom surface of the upper plate 410a are combined to form a buffer space 414. The buffer space 414 is provided as a space for temporarily allowing the gas supplied through the gas supply holes 412 to remain before being supplied to the plasma chamber 100. A gas supply hole 413 is formed in the central area of ​​the lower plate 410b. A plurality of gas supply holes 413 are formed to be spaced apart from each other at predetermined intervals. The gas supply holes 413 are connected to the buffer space 414.

[0069] The distribution plate 420 is located below the lower plate 410b. The distribution plate 420 is configured in a disk shape. Distribution holes 421 are formed in the distribution plate 420. The distribution holes 421 are arranged to extend from the upper surface of the distribution plate 420 to the lower surface. The number of distribution holes 421 is set to correspond to the number of gas supply holes 413, and the positions of the distribution holes 421 correspond to the positions of the gas supply holes 413. The process gas remaining in the buffer space 414 is uniformly supplied to the plasma chamber 100 through the gas supply holes 413 and the distribution holes 421.

[0070] The upper power supply unit 440 applies RF power to the upper board 410a. The upper power supply unit 440 includes an upper RF power supply 441 and a matching circuit.

[0071] 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 mounted inside the lower plate 410b. The heater 510 can be positioned at the edge of the lower plate 410b. The heater 510 can include a heating coil and can be positioned around the entrance 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 can generate direct current. Alternatively, the second upper power source 520 can generate alternating current. The second frequency power generated by the second upper power source 520 is applied to the heater 510, which heats the lower plate 410b by resisting the applied current. The heat generated by the heater 510 heats the lower plate 410b, which in turn heats the distribution plate 420 located below the lower plate 410b to a predetermined temperature. The lower plate 410b can be heated to 60°C. The filter 530 is electrically connected to the second upper power source 520 and the heater 510 in a portion between the second upper power source 520 and the heater 510 .

[0072] Figures 3 to 5 is a block diagram illustrating substrate processing apparatuses according to first, second, and third exemplary embodiments of the present invention.

[0073] exist Figures 3 to 5 In the present invention, common features are described first, and then each feature other than the common features in each figure will be described.

[0074] according to Figures 4 to 6 The substrate processing apparatus 10 may include an RF power supply 222, an impedance matching unit 225, and a processing plasma chamber 100. The substrate processing apparatus 10 performs a plasma process. Herein, the term "plasma process" should be interpreted as a general term including all processes for processing a substrate using plasma. For example, a plasma process may include a plasma deposition process, a plasma etching process, a plasma ashing process, and a plasma cleaning process. In a plasma process, plasma may be formed by applying high-frequency power to a source gas.

[0075] Meanwhile, herein, the substrate needs to be interpreted as a general meaning including all substrates used for manufacturing semiconductor devices or flat panel displays (FPDs) and other products in which patterns are formed on thin films.

[0076] The RF power supply 222 outputs high frequency power. The transmission line connects the RF power supply 222 and the processing plasma chamber 100 and transmits the high frequency power from the RF power supply 222 to the processing plasma chamber 100. The processing plasma chamber 100 performs a plasma process by using the high frequency power. The impedance matching unit 225 is provided on the transmission line and matches the impedance between the processing plasma chamber 100 and the RF power supply 222. According to an exemplary embodiment, the Figure 2 The impedance matching unit 225 may perform matching between the plurality of RF power sources 222 and 223 and the processing plasma chamber 100 .

[0077] The RF power supply 222 outputs high-frequency power. Here, the RF power supply 222 may output high-frequency power in a pulsed mode. The RF power supply 222 may output high-frequency power at a specific frequency. For example, the RF power supply 222 may output high-frequency power at frequencies such as 2 MHz, 13.56 MHz, and 1000 MHz.

[0078] The transmission line transmits high-frequency power and can connect the RF power source 222 and the processing plasma chamber 100 , thereby supplying the high-frequency power outputted by the RF power source 222 to the processing plasma chamber 100 .

[0079] The plasma processing chamber 100 can perform a plasma process using high-frequency power. The plasma processing chamber 100 may include a housing and a plasma generator. The housing provides a space for performing the plasma process. The plasma generator provides plasma to the housing. The plasma generator can form plasma by applying high-frequency power to source gas. When source gas is introduced into the plasma processing chamber 100, the plasma generator applies high-frequency power to the introduced source gas, thereby ionizing and exciting the source gas into a plasma state.

[0080] As the plasma generator, a capacitively coupled plasma generator (CCPG) may be used. The CCPG may include a plurality of electrodes located inside a housing.

[0081] The impedance matching unit 225 is provided on a transmission line connecting the RF power source 222 and the processing plasma chamber 100 , and matches impedances of the RF power source 222 side and the processing plasma chamber 100 side.

[0082] When high-frequency power is transmitted through non-consumable circuit elements (such as capacitors or inductors) and the impedance of the transmitting end and the receiving end do not match, a phase difference will be generated in the high-frequency power supply passing through the non-consumable circuit elements. When a phase difference is generated, the power transmission is delayed, thereby generating a reflected wave and generating reflected power. The reflected power can reduce the power transmission efficiency and become a factor that causes uneven high-frequency power transmission. In particular, when reflected power is generated when high-frequency power is transmitted from the RF power supply 222 to the processing plasma chamber 100 through the transmission line, the power is transmitted unevenly, resulting in a deviation in the plasma density in the processing plasma chamber 100, thereby reducing the yield of the substrate. In addition, the reflected power accumulates in the processing plasma chamber 100, causing arc discharge in the processing plasma chamber 100, which may also directly damage the substrate.

[0083] The impedance matching unit 225 can solve this problem by matching the impedance to remove the reflected power.

[0084] According to an exemplary embodiment, the impedance matching unit 225 may include an impedance measuring device, a reflected power measuring device, a controller, and a matching device. The impedance measuring device measures the impedance of the processing plasma chamber 100. The impedance of the processing plasma chamber 100 may change according to changes in the plasma impedance within the processing plasma chamber 100 during the plasma process. The impedance of the plasma is determined by various conditions, such as the type of source gas, internal pressure, and internal temperature. The impedance measuring device may measure the impedance of the processing plasma chamber 100 and transmit the measured value to the controller. According to an exemplary embodiment, the impedance measuring device may be a second sensor 225a.

[0085] The reflected power measuring device measures the reflected power through the reflected wave. The reflected power measuring device can be installed on the transmission line to measure the reflected power and transmit the measured value to the controller.

[0086] The controller receives the measured values ​​from the impedance measurement device and the reflected power measurement device, generates a control signal for impedance compensation, and transmits the generated control signal to the matching device. The control signal may be a digital signal, such as an on / off signal. The controller may be implemented using hardware, software, or a combination of hardware and software, such as a computer or similar device.

[0087] Depending on the hardware implementation, the controller can be implemented using an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microcontroller, a microprocessor or other electronic devices for performing similar functions.

[0088] Depending on the software implementation, the controller may be implemented using software code in one or more programming languages ​​or software applications. The software may be executed by a controller implemented in hardware. Furthermore, the software may be transferred from an external device, such as a server, to and installed in the aforementioned hardware configuration.

[0089] The matching device matches the impedance between the RF power source 222 and the plasma processing chamber 100. The matching device can be implemented using a circuit formed by resistors, capacitors, inductors, and other various circuit elements. The matching device can match the impedance based on a control signal. The circuit elements of the matching device can be operated based on the control signal, thereby adjusting the resistance, capacitance, inductance, and other electrical characteristics of the matching device, thereby achieving impedance matching.

[0090] In each of the following figures, each feature except for common features in the substrate processing apparatus will be described.

[0091] Figure 4 is a block diagram illustrating a substrate processing apparatus according to a first exemplary embodiment of the present invention.

[0092] refer to Figure 4 The RF power supply 222 of the substrate processing apparatus according to the first exemplary embodiment may include a processing plasma chamber 100 and a first sensor 222a for measuring impedance in a direction of the impedance matching unit 225. In addition, the impedance matching unit 225 of the substrate processing apparatus according to the first exemplary embodiment may include a second sensor 225a for measuring impedance in a direction of the processing plasma chamber 100.

[0093] The impedance matching unit 225 according to the first exemplary embodiment may perform impedance matching by reflecting the impedance measured by the RF power source 222 via the first sensor 222a included in the RF power source 222. The impedance matching unit 225 according to the first exemplary embodiment may perform primary impedance matching by using the value measured by the second sensor 225a and perform secondary impedance matching by using the value measured by the first sensor 222a to correct the difference. Figure 7 A more detailed impedance matching method using the above structure is described in an exemplary embodiment of the present invention.

[0094] Figure 5 is a block diagram illustrating a substrate processing apparatus according to a second exemplary embodiment of the present invention.

[0095] refer to Figure 5The RF power supply of the substrate processing apparatus according to the second exemplary embodiment may include a processing plasma chamber 100, and a first sensor 222a for measuring impedance in a direction of an impedance matching unit 225. In addition, the impedance matching unit 225 of the substrate processing apparatus according to the second exemplary embodiment may include a second sensor 225a for measuring impedance in a direction of the processing plasma chamber 100, and a third sensor 225b for measuring impedance in a direction of the RF power supply 222.

[0096] The second exemplary embodiment is Figure 4 The exemplary embodiment of is different in that a third sensor 225 b for measuring impedance in the direction of the RF power source 222 is additionally included.

[0097] according to Figure 5 The impedance matching unit 225 of the exemplary embodiment of the present invention can perform primary impedance matching by using the value measured by the second sensor 225a, and perform secondary impedance matching by correcting the difference by using the value measured by the first sensor 222a and the value measured by the third sensor 225b. Figure 7 A more detailed impedance matching method using the above structure is described in an exemplary embodiment of the present invention.

[0098] Figure 6 is a block diagram illustrating a substrate processing apparatus according to a third exemplary embodiment of the present invention.

[0099] refer to Figure 6 The impedance matching unit 225 of the substrate processing apparatus according to the third exemplary embodiment may include a second sensor 225 a for measuring impedance in a direction of the process plasma chamber 100 and a third sensor 225 b for measuring impedance in a direction of the RF power source 222 .

[0100] Figure 6 Example embodiments of Figure 4 or Figure 5 The exemplary embodiment of FIG. 5 is different in that the first sensor 222 a included in the RF power source 222 is not included.

[0101] according to Figure 6 The impedance matching unit 225 of the exemplary embodiment of the present invention may perform primary impedance matching by using the value measured by the second sensor 225a and perform secondary impedance matching by using the value measured by the third sensor 225b. More specifically, according to Figure 6 The impedance matching unit 225 of the exemplary embodiment of the present invention can calculate the cable impedance by considering the value measured by the third sensor 225b and the previously measured impedance of the RF power source 222, and perform secondary impedance matching by considering the calculated cable impedance. Figure 8 A more detailed impedance matching method using the above structure is described in an exemplary embodiment of the present invention.

[0102] Figure 7 FIG. 1 is a diagram illustrating the performance of impedance matching by the substrate processing apparatus according to the first exemplary embodiment of the present invention.

[0103] according to Figure 7 , the impedance matching method according to the first exemplary embodiment of the present invention can measure the actual total impedance observed from the RF power source 222 in real time by the first sensor 222a, transmit the measured total impedance to the impedance matching unit 225, and correct the target impedance of the impedance matching unit 225 to meet the maximum power transmission condition Z G =Z T .

[0104] The present invention proposes a system that measures the impedance between RF power source 222 and impedance matching unit 225 in real time, which changes depending on various factors, transmits the real-time measured impedance to impedance matching unit 225, and corrects the total impedance observed from RF power source 222 to 50Ω in real time. The impedance matching method will be described below in order.

[0105] The second sensor 225a in the impedance matching unit 225 measures the impedance Z of the plasma processing chamber 100. L Then, the impedance matching unit 225 is based on the impedance Z L The measured value performs an impedance matching (Z M ). Thereafter, the first sensor 222a can measure the impedance Z observed from the RF power source 222 T =Z c +Z M ≠50+j0 and transmit the measured value to the impedance matching unit 225. Thus, the impedance matching unit 225 can be used to match the Z M and Z T The impedance of the cable is calculated by the difference between the two, and Z is corrected by compensating for the impedance difference of the cable. M .

[0106] The impedance matching method according to the present invention can achieve the following effects. In this method, maximum power transmission conditions can be met by correcting inductance according to cable bending. Furthermore, tool-to-tool matching (TTTM), which is the correspondence between devices, can be improved. Furthermore, by correcting for impedance changes over time due to mechanical and thermal aging of the equipment and cables, the mean time between cleaning (MTBC), which is the equipment inspection cycle, can be improved.

[0107] Furthermore, the existing problem of commercial cables not being long enough to fit the half-wavelength of the RF signal can be resolved. Furthermore, impedance deviations in RF power source 222 can be corrected, reducing equipment setup, maintenance, and repair time. Furthermore, impedance matching can be performed even when devices other than cables are inserted between RF power source 222 and impedance matching unit 225, allowing selection from a variety of cable manufacturers. Furthermore, by comparing the impedances at RF power source 222 and impedance matching unit 225, it is easy to identify abnormal parts of the equipment.

[0108] exist Figure 7 In the embodiment, the impedance matching method according to the first exemplary embodiment has been described, but even in the case where the third sensor 225b is additionally included like the second exemplary embodiment, impedance matching can be performed in a similar manner. When the third sensor 225b is included, the third sensor 225b can measure the impedance Z facing the RF power source 222. G +Z C , so that the impedance Z G +Z C and Z measured by the first sensor 222a T =Z c +Z M The value of Z is exchanged to check more accurately C value, thereby, impedance matching can be performed more accurately by performing secondary impedance matching.

[0109] Figure 8 The diagram illustrates impedance matching performed by a substrate processing apparatus according to a third exemplary embodiment of the present invention.

[0110] The impedance matching methods according to the first and second exemplary embodiments can accurately measure impedance, but have a disadvantage in that the first sensor 222a needs to be additionally installed on the RF power source 222. To remedy this disadvantage, the third exemplary embodiment proposes a system in which only the second sensor 225a and the third sensor 225b are used in the impedance matching unit 225.

[0111] according to Figure 8 The second sensor 225a of the impedance matching unit 225 measures the chamber impedance Z L Then, the impedance matching unit 225 can perform an impedance matching (Z M Then, the third sensor 225b can measure the impedance Z facing the RF power source 222. G +Z C In this case, Z can be measured in advance during the device release phase. G According to one example, Z GThe value of may be 50Ω. The cable impedance Z may be calculated by considering the previously measured impedance 50Ω of the RF power source 222 in the measured impedance. G The impedance matching unit 225 can be used to match the cable impedance Z G With the existing matching impedance Z M Consider together to correct Z M .

[0112] Figure 7 is a flowchart illustrating an impedance matching method according to an exemplary embodiment of the present invention.

[0113] refer to Figure 7 In the impedance matching method, the impedance matching unit 225 may measure the impedance of the processing plasma chamber 100 side, perform primary impedance matching by using the impedance of the processing plasma chamber 100 side, and then perform secondary impedance matching by using an additional measured impedance value.

[0114] The secondary impedance matching method may differ depending on the installation position of the sensor of the substrate processing apparatus.

[0115] According to an exemplary embodiment, performing secondary impedance matching by using the additionally measured impedance value may include measuring the impedance value observed from the RF power source 222 by using the first sensor 222a. Then, impedance matching may be performed to correct the impedance value Z observed from the RF power source 222. c +Z M Z in primary impedance matching M The aforementioned exemplary embodiment is an impedance matching method that can be used in the case where the RF power source 222 includes the first sensor 222a.

[0116] According to another exemplary embodiment of the present invention, performing secondary impedance matching by using an additionally measured impedance value may include measuring, by the impedance matching unit 225, an impedance value facing the RF power source 222 by using the third sensor 225b. Then, the impedance matching unit 225 may calculate the impedance of the cable connecting the impedance matching unit 225 and the RF power source 222 by using the impedance value facing the RF power source 222 and the previously measured impedance of the RF power source 222, and perform impedance matching by taking into account the calculated cable impedance value. In addition, the impedance matching may be performed when the maximum power transmission condition Z is satisfied. G =Z m Impedance matching is performed within the range of

[0117] The above exemplary embodiments are provided to help understand the present invention and do not limit the scope of the present invention. It should be understood that various modified exemplary embodiments of the above exemplary embodiments are also included in the scope of the present invention. The drawings provided in this application only illustrate the best exemplary embodiments of the present invention. The technical scope of the present invention will be defined by the technical spirit of the appended claims, and it should be understood that the technical spirit of the present invention is not limited to the literal description of the claims themselves, but essentially extends to the equivalent scope of the technical value of the present invention.

Claims

1. An apparatus for processing a substrate, the apparatus comprising: RF power supply; a processing chamber that performs plasma processing by using power applied from the RF power supply; an impedance matching unit disposed between the RF power source and the processing chamber and performing matching, The RF power supply includes a first impedance Z measured in the direction of the processing chamber and the impedance matching unit. T The first sensor, and The impedance matching unit reflects the first impedance Z measured by the first sensor in the RF power supply. T To perform impedance matching, wherein the impedance matching unit comprises a second sensor for measuring a second impedance in the direction of the processing chamber, and wherein the impedance matching unit performs impedance matching by further reflecting the second impedance; and a cable connecting the RF power source and the impedance matching unit to each other, Wherein, the impedance matching unit is configured as follows: The impedance matching unit is configured to have a first matching impedance Z by performing a primary impedance matching using the second impedance measured by the second sensor. M ; According to the first matching impedance Z M and the first impedance Z measured by the first sensor T Calculate the impedance of the cable by the difference between Secondary impedance matching is performed based on the calculated impedance of the cable, so that the first matching impedance of the impedance matching unit is adjusted to a second matching impedance. 2 . The apparatus according to claim 1 , wherein the impedance matching unit comprises a third sensor that measures impedance in the direction of the RF power source. 3 . The apparatus according to claim 1 , wherein the impedance matching unit performs the impedance matching within a range that satisfies a maximum power transmission condition. 4 . The apparatus according to claim 3 , wherein the RF power source is provided in plurality, and the impedance matching unit performs the matching between the plurality of RF power sources and the processing chamber.

5. An apparatus for processing a substrate, the apparatus comprising: RF power supply; a processing chamber that performs plasma processing by using power applied from the RF power supply; an impedance matching unit disposed between the RF power source and the processing chamber and performing matching; as well as a cable connecting the RF power source and the impedance matching unit to each other, Wherein, the impedance matching unit includes: a second sensor configured to measure impedance in the direction of the process chamber; and a third sensor configured to measure impedance in the direction of the RF power source, Wherein, the impedance matching unit is configured as follows: performing primary impedance matching by using the impedance measured by the second sensor so that the impedance matching unit has a first matching impedance; calculating the impedance of the cable by using the impedance measured by the second sensor and a value measured by the third sensor and a previously measured impedance of the RF power source; and Secondary impedance matching is performed based on the calculated impedance of the cable to adjust the first matching impedance of the impedance matching unit to a second matching impedance. The apparatus according to claim 5 , wherein the secondary impedance matching is performed by taking into account an impedance of the cable. 7 . The apparatus according to claim 5 , wherein the impedance matching unit performs the impedance matching within a range that satisfies a maximum power transmission condition. 8 . The apparatus according to claim 7 , wherein the RF power source is provided in plurality, and the impedance matching unit performs the matching between the plurality of RF power sources and the processing chamber.

9. A method for performing impedance matching in a substrate processing apparatus by connecting an impedance matching unit between an RF power source and a processing chamber, the substrate processing apparatus performing plasma processing in the processing chamber by using power applied from the RF power source, the method comprising: measuring the impedance of the processing chamber side by the impedance matching unit; performing primary impedance matching by using the impedance of the process chamber side; By using the additional measured impedance value to perform secondary impedance matching, wherein the RF power supply comprises a first sensor for measuring a first impedance in a direction between the processing chamber and the impedance matching unit, wherein the impedance matching unit performs impedance matching by reflecting the first impedance measured by the first sensor in the RF power source, wherein the impedance matching unit comprises a second sensor for measuring a second impedance in the direction of the processing chamber, and wherein the impedance matching unit performs impedance matching by further reflecting the second impedance; and a cable connecting the RF power source and the impedance matching unit to each other, Wherein, the impedance matching unit is configured as follows: performing primary impedance matching by using the second impedance measured by the second sensor so that the impedance matching unit has a first matching impedance; calculating the impedance of the cable according to a difference between the first matching impedance and the first impedance measured by the first sensor; Secondary impedance matching is performed based on the calculated impedance of the cable, so that the first matching impedance of the impedance matching unit is adjusted to a second matching impedance.

10. The method of claim 9, wherein said performing said secondary impedance matching by using said additionally measured impedance value comprises measuring an impedance value observed from said RF power source.

11. The method of claim 10, wherein performing the secondary impedance matching by using the additionally measured impedance value comprises performing the impedance matching to correct a difference between the impedance value observed from the RF power source and a resultant value of the primary impedance matching.

12. The method of claim 9, wherein performing the secondary impedance matching by using the additionally measured impedance value comprises measuring an impedance value facing the RF power source by the impedance matching unit.

13. The method according to claim 12, further comprising: The impedance of the cable connecting the impedance matching unit and the RF power source is calculated by the impedance matching unit by using the impedance value facing the RF power source and the previously measured impedance of the RF power source. The method according to claim 13 , wherein the impedance matching is performed by taking into account an impedance value of the cable. 15 . The method according to claim 9 , wherein the impedance matching unit performs the impedance matching within a range that satisfies a maximum power transmission condition.

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