RF electrostatic chuck filter circuit

Abstract

[0003] Embodiments described herein relate to an apparatus and method for significantly reducing the occurrence of radio frequency (RF) coupling through a chuck electrode. The chuck electrode is disposed within an electrostatic chuck positioned above a substrate support. The substrate support is coupled to a processing chamber body. An RF source is used to generate a plasma in a processing space adjacent to the substrate support. An impedance matching circuit is disposed between the RF source and the chuck electrode disposed on the electrostatic chuck. An electrostatic chuck filter is coupled between the chuck electrode and a chuck power supply.

Description

[Technical field]

[0001] TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate generally to semiconductor processing, and more specifically to an apparatus and method for generating and controlling radio frequency plasma for thin film deposition. [Background technology]

[0002] 2. Description of Related Art

[0002] In the manufacture of integrated circuits, deposition processes such as chemical vapor deposition (CVD) are often used to deposit films of various materials on substrates. In plasma enhanced chemical vapor deposition (PECVD), for example, electromagnetic energy is applied to at least one precursor gas or vapor to generate a plasma.

[0003]

[0003] In some embodiments, the electromagnetic energy used to generate the plasma can be radio frequency (RF) power. However, when RF power is used, capacitive coupling can occur between the plasma and the chuck electrode in an electrostatic chuck. The capacitive coupling can result in RF coupling, which induces high RF voltages and currents on and through the chuck electrode, resulting in loss of power and damage to the power supply of the chuck electrode.

[0004]

[0004] Therefore, there is a need for improved apparatus and methods for RF power application. Summary of the Invention

[0005] In one embodiment, an apparatus is provided that includes a chamber body and a lid defining a processing space therein. A substrate support is disposed within the processing space. A first electrode is embedded within the substrate support. A radio frequency (RF) source is coupled to the first electrode. An impedance matching network is disposed between the RF source and the first electrode. A second electrode is embedded within the substrate support. A power source is coupled to the second electrode. An electrode filter is disposed between and coupled to the second electrode and the power source.

[0006] In another embodiment, an apparatus is provided that includes a chamber body and a lid defining a processing space therein. A gas distribution plate is disposed within the processing space and positioned adjacent to the lid. A substrate support is disposed within the processing space. A first electrode is embedded within the substrate support. A radio frequency (RF) source is coupled to the first electrode. An impedance matching circuit is disposed between the RF source and the electrode. A second electrode is embedded within the substrate support. A power source is coupled to the second electrode. An electrode filter is disposed between the second electrode and the power source. The electrode filter includes a first inductor coupled to the second electrode. The second inductor is disposed in series with the first inductor. A third inductor is disposed in series with the first inductor and the second inductor. A resistor is disposed in series with the first inductor, the second inductor, and the third inductor. The resistor is coupled to the power source, and a first capacitor is disposed in parallel with the second inductor.

[0007] In yet another embodiment, an apparatus is provided that includes a chamber body and a lid defining a processing space therein. A gas distribution plate is disposed within the processing space and positioned adjacent to the lid. A substrate support is disposed within the processing space. A first electrode is embedded within the substrate support. A second electrode is embedded within the substrate support between the first electrode and a surface of the substrate support facing the lid. A radio frequency (RF) source is coupled to the first electrode. An impedance matching network is disposed between the RF source and the first electrode. A power source is coupled to the second electrode. An electrode filter is disposed between the second electrode and the power source. The electrode filter includes a first inductor coupled to the second electrode, a second inductor in series with the first inductor, a third inductor in series with the first inductor and the second inductor, and a resistor in series with the first inductor, the second inductor, and the third inductor. The resistor is coupled to the power source. The electrode filter also includes a first capacitor in parallel with the second inductor, a first ground path coupled to the electrode filter between the second inductor and a third inductor, and a second ground path coupled to the electrode filter between the third inductor and a resistor. The first ground path includes the second capacitor. The second ground path includes the third capacitor.

[0008]

[0008] In order that the above-mentioned features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly summarized above may be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only show exemplary embodiments, and therefore should not be considered as limiting the scope thereof, and the present disclosure may admit of other equally effective embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a processing chamber, according to one embodiment. [Figure 2A] FIG. 2 is a schematic diagram of a filter circuit, according to one embodiment. [Figure 2B]FIG. 2 is a schematic diagram of a filter circuit, according to one embodiment. [Diagram 3] 2 is a schematic diagram of an impedance matching circuit according to one embodiment. [Figure 4] FIG. 2 is a top view of a cluster tool apparatus according to one embodiment described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010]

[0014] For ease of understanding, wherever possible, the same reference numerals have been used to designate identical elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

[0011]

[0015] The embodiments described herein relate to an apparatus and method for substantially reducing the incidence of radio frequency (RF) coupling through a chuck electrode. The chuck electrode is disposed within a substrate support coupled to a processing chamber body. A RF source is used to generate a plasma in a processing space adjacent to the substrate support. An impedance matching circuit is disposed between the RF source and the chuck electrode disposed within the substrate support. An electrostatic chuck filter is coupled between the chuck electrode and the chuck power supply to reduce the incidence of damage to the chuck electrode and a chuck power supply coupled thereto.

[0012]

[0016] 1 is a schematic diagram of a processing chamber 100 according to certain embodiments. The processing chamber 100 includes a chamber body 102 and a lid 104 defining a processing space 120 therein. A substrate support 114 and a gas distribution plate 108 are disposed within the processing space 120. The substrate support 114 is supported within the chamber body 102 via a stem 106. The substrate support 114 includes one or more conductive plates, insulating plates, fixture plates, cooling channels, etc. to facilitate processing of the substrate. In one embodiment, the stem 106 is substantially perpendicular to the lid 104 and is coupled to the chamber body 102 opposite the lid 104 or disposed through an opening in the chamber body 102 opposite the lid.

[0013]

[0017] In one embodiment, which may be combined with one or more of the embodiments described above, the substrate support 114 is fabricated from an aluminum-containing material. For example, the substrate support 114 may be fabricated from an aluminum nitride material. An electrostatic chuck 115 may be positioned on an upper surface of the substrate support 114 to facilitate securing the substrate during processing. The electrostatic chuck 115 includes an electrode 122 disposed therein. In one embodiment, which may be combined with one or more of the embodiments described above, the electrode 122 is a conductive mesh.

[0014]

[0018] The top surface 116 of the electrostatic chuck 115 can have a number of raised portions (not shown) formed thereon. The raised portions can contact a substrate (not shown) disposed on the top surface 116 of the electrostatic chuck 115. A gas can be flowed between the substrate and the surface 116 of the electrostatic chuck 115 and / or between the substrate support 114 and the bottom surface of the electrostatic chuck to maintain thermal equilibrium between the substrate and the substrate support 114. In such examples, the fluid can be temperature controlled, for example, via a heat exchanger.

[0015]

[0019] A gas distribution plate 108 is coupled to the chamber body 102. A plenum 110 is defined between the lid 104 and the gas distribution plate 108. The gas distribution plate 108 is disposed opposite the substrate support 114. A plurality of holes 112 are formed through the gas distribution plate 108. The plurality of holes 112 are dispersed throughout the gas distribution plate 108 to facilitate the flow of process gases into the process space 120.

[0016]

[0020] A gas supply system 126 is coupled to the lid 104 via supply lines 128. The gas supply system 126 supplies one or more gases to the processing chamber 100 for processing a substrate disposed therein. As the one or more gases enter the processing chamber 100 through the lid 104, the gases enter the plenum 110 and flow through a plurality of holes 112 in the gas distribution plate 108. The plurality of holes 112 distribute the gas radially across a surface 116 of the electrostatic chuck 115.

[0017]

[0021] The electrode 118 is embedded in the substrate support 114. Radio frequency (RF) power is supplied to the electrode 118 via an RF source 134. The RF source 134 is coupled to the electrode 118 via an impedance matching circuit 136. The RF source 134 can supply RF power to the electrode 118 at one or more frequencies simultaneously. For example, the RF source 134 supplies RF power to the electrode at a frequency of about 13.56 MHz and a frequency of about 40 MHz. To do so, the RF source 134 includes a frequency generator 138A, 138B for each frequency. Although two frequency generators 138A, 138B are shown, the RF source 134 can include any number of frequency generators for each frequency used. The characteristic impedance of the RF source 134 is about 50 ohms.

[0018]

[0022] The impedance matching circuit 136 enables striking and maintaining of a plasma in the process space 120. The impedance matching circuit 136 couples RF signals of various frequencies from the RF source 134. The impedance matching circuit 136 transmits the coupled RF signal to an electrode 118 embedded in the electrostatic chuck 115. The coupled RF signal is transmitted to the process gas in the process space 120 to generate a capacitively coupled plasma therein. The chamber body 102 is coupled to ground and provides an RF return path to facilitate generation of the capacitively coupled plasma.

[0019]

[0023] In one embodiment, the RF power supplied to the electrode 118 is between about 5 kW and about 15 kW, for example, between about 8 kW and about 13 kW, for example, about 10 kW. The RF current supplied to the electrode 118 is between about 120 amperes and about 80 amperes, for example, about 110 amperes. The high RF current is made possible by the relatively low resistance (between about 0.2 ohms and about 0.4 ohms) of the impedance matching circuit 136. The voltage supplied to the electrode 118 is between about 8 kV and about 13 kV, for example, about 10 kV. The impedance angle of the impedance matching circuit 136 is between about 85 degrees and about 90 degrees, for example, between about 87 degrees and about 89 degrees.

[0020]

[0024] The electrode 122 is a component of an electrostatic chuck 115 that is disposed on the substrate support 114. A dielectric layer (not shown) may be disposed on the electrostatic chuck 115 to form a surface 116 of the electrostatic chuck 115. A power supply 132 is coupled to the electrode 122 and provides sufficient power to the electrode 122 to generate an electrostatic force to hold the substrate on the surface 116 of the electrostatic chuck 115. In an embodiment, which may be combined with one or more of the embodiments described above, the power supply 132 provides direct current (DC) power to the electrode 122.

[0021]

[0025] The coupling capacitance of the electrode 122 is between about 800 pF and about 2500 pF. In an embodiment that may be combined with one or more of the embodiments described above, the electrode 122 is made of an aluminum-containing material. In an embodiment that may be combined with one or more of the embodiments described above, the electrode 122 is disposed between the electrode 118 and the surface 116 of the electrostatic chuck 115.

[0022]

[0026] As plasma is generated in the process space 120, RF current enters the electrode 122 and travels toward the power supply 132 (e.g., RF leakage). RF current entering and passing through the power supply 132 can damage the power supply 132, resulting in a loss of power to the electrode and a loss of chucking force applied to a substrate disposed thereon. To prevent damage to the power supply 132, a filter circuit 130 is disposed between the power supply 132 and the electrode 122.

[0023]

[0027] The filter circuit 130, such as an RF filter, substantially blocks RF current from entering the power supply 132. In this manner, the filter circuit 130 significantly reduces the occurrence of damage to the power supply 132 by redirecting the RF current (e.g., to ground). The input impedance of the filter circuit 130 is high enough relative to ground that minimal current is diverted away from the substrate and plasma. However, the impedance of the filter circuit 130 is low enough to substantially prevent current from entering the power supply 132.

[0024]

[0028] The controller 124 is coupled to the processing chamber 100 and controls various aspects of the processes performed therein. For example, the controller 124 controls the flow of process gases from the gas delivery system 126 to the processing space 120. The controller 124 can also control the manner in which substrates are moved into and out of the processing chamber 100. In addition, the controller 124 can control aspects of the impedance matching circuit 136 and the filter circuit 130, such as the capacitance of a variable capacitor.

[0025]

[0029] 2A is a schematic diagram of a filter circuit 200 according to one embodiment. The filter circuit 200 may correspond to the filter circuit 130 described with respect to FIG. 1 above. The filter circuit 200 includes a first inductor 202 coupled to an electrode, such as the electrode 122 shown in FIG. 1. A second inductor 206 is disposed in series with the first inductor 202. A third inductor 210 is disposed in series with the first inductor 202 and the second inductor 206. A resistor 214 is disposed in series with the first inductor 202, the second inductor 206, and the third inductor 210. The resistor 214 is coupled to a power source, such as the power source 132 shown in FIG. 1.

[0026]

[0030] The first capacitor 204 is arranged in parallel with the second inductor 206. The first capacitor 204 and the second inductor 206 form an LC resonant circuit. The first ground path is coupled to the filter circuit 200 between the second inductor 206 and the third inductor 210 and includes a second capacitor 208 coupled to ground. The second ground path is coupled to the filter circuit 200 between the third inductor 210 and a resistor 214 and includes a third capacitor 212 coupled to ground. The second capacitor 208 and the third capacitor 212 are shunt capacitors coupled to ground.

[0027]

[0031] A first portion 231 of the filter circuit includes a first inductor 202, a second inductor 206, and a first capacitor 204. The first portion 231 is the inductive portion of the filter circuit 200. Most of the 13.56 MHz RF current entering the filter circuit 200 is rejected by the first inductor 202. Similarly, most of the RF current at 40 MHz is rejected by the LC resonant circuit including the second inductor 206 and the first capacitor 204.

[0028]

[0032] The second section 233 of the filter circuit 200 is a low pass filter that includes a second capacitor 208, a third inductor 210, and a third capacitor 212. The resistor 214 is an optional current limiting resistor between the second section 233 and the power supply. The second section 233 removes remaining RF current from the filter circuit 200 and prevents RF current leakage to the power supply connected to the resistor 214.

[0029]

[0033] The values ​​of the components of the filter circuit 200 (e.g., the first inductor 202, the second inductor 206, the third inductor 210, the first capacitor 204, the second capacitor 208, the third capacitor 212, and the resistor 214) can be adjusted based on one or more frequencies of the RF current flowing therethrough. For example, in one embodiment that can be combined with one or more of the embodiments described above, the first inductor 202 has an inductance of about 14 μH to about 25 μH (e.g., about 20 μH), the third inductor 210 has an inductance of about 8 μH to about 13 μH (e.g., about 10 μH), the second capacitor 208 and the third capacitor 212 have an inductance of about 800 pF to about 15000 pF (e.g., about 1000 pF), and the resistor has a resistance of about 1 Ω to about 5 Ω (e.g., about 2 Ω).

[0030]

[0034] The resonant LC circuit including the first capacitor 204 and the second inductor 206 may have a resonant frequency of 40 MHz. The values ​​of the components of the first portion 231 (e.g., the first inductor 202, the second inductor 206, and the first capacitor 204) may be based on an input frequency of 13.56 MHz. That is, the first portion 231 may be designed to filter out RF currents at a frequency of 13.56 MHz.

[0031]

[0035] Advantageously, the filter circuit 200 shown in Figure 2A significantly reduces the RF current flowing from the electrode 122 to the power supply 132 shown in Figure 1. Thus, the filter circuit 200 significantly reduces the occurrence and amount of damage to the power supply.

[0032]

[0036] 2B is a schematic diagram of a filter circuit 270, according to one embodiment. Filter circuit 270 may correspond to filter circuit 130 described with respect to FIG 1 above. That is, filter circuit 270 may be an alternative design to filter circuit 200 described above with respect to FIG 2A.

[0033]

[0037] The filter circuit 270 includes a first portion 260 and a second portion 262. The first portion 260 includes a first bank of inductors 230 and a second bank of inductors 232 in series. The second portion 262 includes a bank of capacitors 234, a third bank of inductors 236, and a shunt capacitor 254. The bank of capacitors 234 and the shunt capacitor 254 are in parallel. As shown, the first bank of inductors 230 includes four inductors 240a, 240b, 240c, and 240d in parallel. The second bank of inductors 232 includes four inductors 242a, 242b, 242c, and 242d in parallel. The first portion 260 of the filter circuit 270 has a coupled inductance of 20 μH.

[0034]

[0038] As shown, the second portion 262 of the filter circuit 270 is a low pass filter. The bank of capacitors 234 includes four capacitors 246, 248, 250, and 252. The third bank of inductors includes three inductors 244a, 244b, and 244c in parallel. The capacitance of each of the capacitors 246, 248, 250, 252, 254 is 1000 pF. The inductance of the third bank of inductors 236 is approximately 10 μH. The values ​​of the components of the filter circuit 270 can be adjusted based on one or more input frequencies to be rejected by the filter circuit 270.

[0035]

[0039] 3 is a schematic diagram of an impedance matching circuit 300, according to one embodiment. The impedance matching circuit 300 includes a first variable capacitor 306 and an inductor 308 in series. A second variable capacitor 304 is coupled to ground and to the impedance matching circuit 300 upstream of the first variable capacitor 306. The impedance matching circuit 300 provides an input impedance for a plasma formed in a processing chamber (e.g., processing chamber 100) as described with respect to FIG. 1 above.

[0036]

[0040] 4 is a top view of a cluster tool apparatus 400 according to one embodiment described herein. The apparatus 400 includes multiple processing chambers 402, 404, 406, and 408, a transfer chamber 420, and load lock chambers 410 and 412. Each of the processing chambers 402, 404, 406, and 408 are coupled to the transfer chamber 420. Although four processing chambers 402, 404, 406, and 408 are shown in FIG. 4, any number of processing chambers can be coupled to the transfer chamber 420.

[0037]

[0041] In an embodiment that may be combined with one or more of the embodiments described above, processing chamber 402 is disposed adjacent to processing chamber 408. In an embodiment, processing chamber 404 is disposed adjacent to processing chamber 402. In an embodiment that may be combined with one or more of the embodiments described above, processing chamber 406 is disposed adjacent to processing chamber 404. In an embodiment that may be combined with one or more of the embodiments described above, each processing chamber 402, 404, 406, and 408 corresponds to processing chamber 100 shown in FIG.

[0038]

[0042] The transfer chamber 420 can transfer substrates between the load lock chambers 410, 412 and the processing chambers 402, 404, 406, and 408. A transfer robot 414 is disposed within the transfer chamber 420. The transfer robot 414 can be a single blade robot or a dual blade robot. The transfer robot 414 has a substrate transfer blade 416 attached to the distal end of an extendable arm. The blade 416 is used to support and carry individual substrates between the processing chambers 402, 404, 406, and 408. The transfer chamber 420 is maintained under vacuum or otherwise in a reduced oxygen environment.

[0039]

[0043] A controller 430 is coupled to the apparatus 400. The controller 430 includes a central processing unit (CPU) (not shown). The controller 430 can be one of any form of general-purpose computer processor that can be used to control various processing chambers and sub-processors. The controller 430 can be coupled to individual or shared controllers of the processing chambers 402, 404, 406, and 408. The controller 430 can control the movement of a transfer robot 414 to transport substrates within the apparatus 400.

[0040]

[0044] In one embodiment, which can be combined with one or more of the embodiments described above, adjacent processing chambers, such as processing chambers 402 and 408, have shared gas supply systems, RF sources, controllers, and / or vacuum systems. These shared systems increase the throughput of processes performed in the processing chambers and the uniformity of the deposited films. The shared systems also reduce costs associated with the processes.

[0041]

[0045] Disclosed advantages include a filter circuit for reducing the amount of RF current (e.g., RF leakage) that enters the DC power supply and damages the DC power supply. The filter circuit allows the RF current to be redirected away from the DC power supply and back toward the RF source. The filter circuit also prevents power loss to the chuck electrode and loss of chucking force applied to the substrate from occurring.

[0042]

[0046] While the above is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is determined by the following claims.

Claims

1. a chamber body and a lid defining a processing space therein; a substrate support disposed within the processing space; a gas distribution plate coupled to the chamber body and positioned opposite the substrate support; a first electrode embedded in the substrate support; a radio frequency (RF) source coupled to the first electrode; an impedance matching circuit disposed between the RF source and the first electrode; a second electrode embedded in the substrate support; a power source coupled to the second electrode; an electrode filter disposed between and coupled to the second electrode and the power source; Equipped with The electrode filter includes: a first inductor coupled to the second electrode; a second inductor in series with the first inductor; a third inductor in series with the first inductor and the second inductor; a resistor in series with the first inductor, the second inductor, and the third inductor, the resistor coupled to the power source; a first capacitor in parallel with the second inductor; a first ground path coupled to the electrode filter between the second inductor and the third inductor, the first ground path including a second capacitor; a second ground path coupled to the electrode filter between the third inductor and the resistor, the second ground path including a third capacitor; An apparatus comprising:

2. The device of claim 1 , wherein the second electrode comprises a conductive mesh.

3. The apparatus of claim 1 , wherein the second electrode is disposed between the first electrode and a surface of the substrate support opposite the gas distribution plate.

4. a chamber body and a lid defining a processing space therein; a gas distribution plate disposed within the processing space and coupled to the chamber body; a substrate support disposed within the processing space; a first electrode embedded in the substrate support; a power source coupled to the first electrode; an electrode filter disposed between the first electrode and the power source, a first inductor coupled to the first electrode; a second inductor in series with the first inductor; a third inductor in series with the first inductor and the second inductor; a resistor in series with the first inductor, the second inductor, and the third inductor, the resistor coupled to the power source; a first capacitor in parallel with the second inductor; a first ground path coupled to the electrode filter between the second inductor and the third inductor, the first ground path including a second capacitor; and a second ground path coupled to the electrode filter between the third inductor and the resistor, the second ground path including a third capacitor; an electrode filter comprising: a second electrode embedded in the substrate support; a radio frequency (RF) source coupled to the second electrode; an impedance matching circuit disposed between the RF source and the second electrode; An apparatus comprising:

5. The device of claim 4 , wherein the first electrode comprises a conductive mesh.

6. The apparatus of claim 4 , wherein the first electrode is disposed between the second electrode and a surface of the substrate support opposite the gas distribution plate.

7. a chamber body and a lid defining a processing space therein; a gas distribution plate disposed within the processing space and positioned adjacent to the lid; a substrate support disposed within the processing space; a first electrode embedded in the substrate support; a second electrode embedded in the substrate support between the first electrode and a surface of the substrate support opposite the lid; a radio frequency (RF) source coupled to the first electrode; an impedance matching circuit disposed between the RF source and the first electrode; a power source coupled to the second electrode; an electrode filter disposed between the second electrode and the power source, a first inductor coupled to the second electrode; a second inductor in series with the first inductor; a third inductor in series with the first inductor and the second inductor; a resistor in series with the first inductor, the second inductor, and the third inductor, the resistor coupled to the power source; a first capacitor in parallel with the second inductor; a first ground path coupled to the electrode filter between the second inductor and the third inductor, the first ground path including a second capacitor; and a second ground path coupled to the electrode filter between the third inductor and the resistor, the second ground path including a third capacitor; An electrode filter including: An apparatus comprising:

8. The apparatus of claim 7 , wherein the second electrode comprises a conductive mesh.

9. The apparatus of claim 7 , wherein the second electrode generates an electrostatic force on the surface of the substrate support.

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