RF electrostatic chuck filter circuit

Abstract

To provide a device and method for greatly reducing the occurrence of high-frequency (RF) coupling through chuck electrodes.SOLUTION: In a processing chamber 100, a chuck electrode 122 is disposed in an electrostatic chuck 115 positioned on a substrate support 114. The substrate support is connected to a chamber body 102. A plasma is generated in a processing space 120 adjacent to the substrate support using an RF source 134. An impedance matching circuit 136 is disposed between the RF source and an electrode 118 disposed on the substrate support. An electrostatic chuck filter 130 is connected between the chuck electrode and a chuck power supply 132.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001]

[0001] Embodiments of the present disclosure generally relate to semiconductor processing, and more specifically, to apparatuses and methods for generating and controlling high-frequency plasmas for thin-film deposition.

Background Art

[0002] 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 a substrate. 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 examples, the electromagnetic energy used to generate the plasma can be high-frequency (RF) power. However, when RF power is used, capacitive coupling can occur between the plasma and the chuck electrode in an electrostatic chuck. Capacitive coupling results in RF coupling, inducing high RF voltages and currents on and through the chuck electrode, which in turn causes power loss and damage to the power supply of the chuck electrode.

[0004]

[0004] Therefore, improved apparatuses and methods for RF power application are needed.

Summary of the Invention

[0005]

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

[0006]

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

[0007]

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

[0008]

[0008] To enable a more detailed understanding of the above-described features of the present disclosure, a more specific description of the present disclosure, briefly summarized above, is obtained by reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate exemplary embodiments only and should not be considered as limiting the scope thereof, and the present disclosure may admit other equally effective embodiments.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010]

[0014] For ease of understanding, the same reference numbers are used to indicate the same elements common to the figures, where possible. The elements and features of one embodiment may be beneficially incorporated into other embodiments without further description.

[0011]

[0015] The embodiments described in this specification relate to devices and methods for substantially reducing the generation of high-frequency (RF) coupling through a chuck electrode. The chuck electrode is disposed within a substrate support coupled to a process chamber body. A plasma is generated in a process space adjacent to the substrate support using an RF source. 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 occurrence of damage to the chuck electrode and the chuck power supply connected thereto.

[0012]

[0016] Figure 1 is a schematic diagram of a processing chamber 100 according to a particular embodiment. The processing chamber 100 includes a chamber body 102 and a lid 104 that defines 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, equipment 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 connected to the chamber body 102 on the opposite side of the lid 104 or is disposed through an opening in the chamber body 102 on the opposite side of the lid.

[0013]

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

[0014]

[0018] The upper surface 116 of the electrostatic chuck 115 can have a plurality of raised portions (not shown) formed thereon. The raised portions can contact a substrate (not shown) disposed on the upper surface 116 of the electrostatic chuck 115. 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 lower surface of the electrostatic chuck to maintain thermal equilibrium between the substrate and the substrate support 114. In such an example, the fluid can be temperature-controlled via, for example, a heat exchanger.

[0015]

[0019] The gas distribution plate 108 is connected to the chamber body 102. The plenum 110 is defined between the lid 104 and the gas distribution plate 108. The gas distribution plate 108 is disposed on the opposite side of 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 inflow of the processing gas into the processing space 120.

[0016]

[0020] The gas supply system 126 is connected to the lid 104 via the supply line 128. The gas supply system 126 supplies one or more gases to the processing chamber 100 to process the substrate disposed therein. When one or more gases enter the processing chamber 100 through the lid 104, the gas enters the plenum 110 and flows through the plurality of holes 112 of the gas distribution plate 108. The plurality of holes 112 radially disperse the gas over the entire surface 116 of the electrostatic chuck 115.

[0017]

[0021] The electrode 118 is embedded in the substrate support 114. High-frequency (RF) power is supplied to the electrode 118 via the RF source 134. The RF source 134 is connected to the electrode 118 via the 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 frequency generators 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 the striking and maintenance of the plasma within the processing 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 signals to the electrode 118 embedded within the electrostatic chuck 115. The coupled RF signals are transmitted to the processing gas within the processing space 120 to generate a capacitively coupled plasma therein. The chamber body 102 is connected to ground and provides an RF return path for facilitating the 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 1 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 the electrostatic chuck 115 disposed on the substrate support 114. A dielectric layer (not shown) can be disposed on the electrostatic chuck 115 to form the surface 116 of the electrostatic chuck 115. The power supply 132 is connected to the electrode 122 and supplies sufficient power to the electrode 122 to generate an electrostatic force for holding the substrate on the surface 116 of the electrostatic chuck 115. In one embodiment that can be combined with one or more of the above-described embodiments, the power supply 132 supplies 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 one embodiment that can be combined with one or more of the above-described embodiments, the electrode 122 is manufactured from an aluminum-containing material. In one embodiment that can be combined with one or more of the above-described embodiments, the electrode 122 is disposed between the electrode 118 and the surface 116 of the electrostatic chuck 115.

[0022]

[0026] As the plasma is generated within the processing space 120, the RF current enters the electrode 122 and proceeds towards the power supply 132 (e.g., RF leakage). The RF current entering and passing through the power supply 132 can damage the power supply 132, resulting in power loss to the electrode and loss of the chucking force applied to the 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] A filter circuit 130, such as an RF filter, substantially blocks the RF current from entering the power supply 132. In this way, the filter circuit 130 greatly 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 with respect to ground that a minimal current is diverted from the substrate and the plasma. However, the impedance of the filter circuit 130 is low enough to substantially prevent the current from entering the power supply 132.

[0024]

[0028] The controller 124 is connected to the processing chamber 100 and controls various aspects of the processing performed within the processing chamber. For example, the control device 124 controls the flow rate of the processing gas from the gas supply system 126 to the processing space 120. Also, the controller 124 can control the manner in which the substrate is loaded and unloaded to and from the processing chamber 100. Further, the controller 124 can control aspects of the impedance matching circuit 136 and the filter circuit 130, such as the capacitance of the variable capacitor.

[0025]

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

[0026]

[0030] A first capacitor 204 is arranged in parallel with respect to the second inductor 206. The first capacitor 204 and the second inductor 206 form an L-C resonance circuit. A first ground path is connected to the filter circuit 200 between the second inductor 206 and the third inductor 210 and includes a second capacitor 208 connected to ground. A second ground path is connected to the filter circuit 200 between the third inductor 210 and the resistor 214 and includes a third capacitor 212 connected to ground. The second capacitor 208 and the third capacitor 212 are shunt capacitors connected to ground.

[0027]

[0031] A first portion 231 of the filter circuit includes the first inductor 202, the second inductor 206, and the first capacitor 204. The first portion 231 is an inductive portion of the filter circuit 200. Most of the 13.56 MHz RF current entering the filter circuit 200 is removed by the first inductor 202. Similarly, most of the RF current at 40 MHz is removed by the L-C resonance circuit including the second inductor 206 and the first capacitor 204.

[0028]

[0032] The second portion 233 of the filter circuit 200 is a low-pass filter including 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 portion 233 and the power supply. The second portion 233 removes the remaining RF current from the filter circuit 200 to prevent leakage of RF current 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 above-described embodiments, the first inductor 202 has an inductance from about 14 μH to about 25 μH (e.g., about 20 μH), the third inductor 210 has an inductance from about 8 μH to about 13 μH (e.g., about 10 μH), the second capacitor 208 and the third capacitor 212 have an inductance from about 800 pF to about 15000 pF (e.g., about 1000 pF), and the resistor has a resistance from about 1 Ω to about 5 Ω (e.g., about 2 Ω).

[0030]

[0034] The resonant L-C circuit including the first capacitor 204 and the second inductor 206 can 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) can be based on the input frequency of 13.56 MHz. That is, the first portion 231 can be designed to remove RF current at a frequency of 13.56 MHz.

[0031]

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

[0032]

[0036] Figure 2B is a schematic diagram of a filter circuit 270 according to an embodiment. The filter circuit 270 may correspond to the filter circuit 130 described with respect to FIG. 1 above. That is, the filter circuit 270 can be an alternative design to the 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 in series a first bank of inductors 230 and a second bank of inductors 232. 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 capacitor 246, 248, 250, 252, 254 is 1000 pF. The inductance of the third bank of inductors 236 is about 10 μH. The values of the components of the filter circuit 270 can be adjusted based on one or more input frequencies to be removed by the filter circuit 270.

[0035]

[0039] Figure 3 is a schematic diagram of impedance matching 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 connected to ground and the impedance matching circuit 300 upstream of the first variable capacitor 306. The impedance matching circuit 300 provides the input impedance of the plasma formed in the processing chamber (e.g., processing chamber 100) described with respect to FIG. 1 above.

[0036]

[0040] Figure 4 is a plan view of a cluster tool apparatus 400 according to one embodiment described herein. The apparatus 400 includes a plurality of 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 is connected 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 connected to the transfer chamber 420.

[0037]

[0041] In one embodiment that can be combined with one or more of the above-described embodiments, the processing chamber 402 is disposed adjacent to the processing chamber 408. In one embodiment, the processing chamber 404 is disposed adjacent to the processing chamber 402. In one embodiment that can be combined with one or more of the above-described embodiments, the processing chamber 406 is disposed adjacent to the processing chamber 404. In one embodiment that can be combined with one or more of the above-described embodiments, each of the processing chambers 402, 404, 406, and 408 corresponds to the processing chamber 100 shown in FIG. 1.

[0038]

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

[0039]

[0043] Controller 430 is connected to apparatus 400. Controller 430 includes a central processing unit (CPU) (not shown). 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. Controller 430 can be connected to individual or shared controllers for processing chambers 402, 404, 406, and 408. Controller 430 can control the movement of transfer robot 414 for transporting substrates within apparatus 400.

[0040]

[0044] In one embodiment that can be combined with one or more of the above-described embodiments, adjacent processing chambers, such as processing chambers 402 and 408, have a shared gas supply system, RF source, controller, and / or vacuum system. These shared systems increase the throughput of the processes executed within the processing chambers and the uniformity of the deposited films. The shared systems also reduce the costs associated with processing.

[0041]

[0045] Advantages of the disclosure include a filter circuit for entering a DC power supply and reducing the amount of RF current (e.g., RF leakage) that damages the DC power supply. The filter circuit enables the RF current to change direction so that it leaves the DC power supply and returns toward the RF source. The filter circuit also prevents the occurrence of power loss to the chuck electrode and loss of the chucking force applied to the substrate.

[0042]

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

Claims

1. A chamber body, a lid that defines a processing space inside thereof, a substrate support disposed in the processing space, a first electrode embedded in the substrate support, a high-frequency (RF) source connected 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 supply connected to the second electrode, an electrode filter disposed between the second electrode and the power supply and connected thereto and comprising an apparatus.

2. The electrode filter a first inductor connected 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 and connected to the power supply, a first capacitor in parallel with the second inductor, a first grounding path connected to the electrode filter between the second inductor and the third inductor and including a second capacitor, a second grounding path connected to the electrode filter between the third inductor and the resistor and including a third capacitor and comprising the apparatus according to Claim 1.

3. The apparatus according to Claim 2, wherein the second electrode comprises a conductive mesh.

4. The apparatus according to Claim 1, further comprising a gas distribution plate connected to the chamber body and disposed on the opposite side of the substrate support.

5. The apparatus according to Claim 4, wherein the second electrode is disposed between the first electrode and the surface of the substrate support facing the gas distribution plate.

6. A chamber body, a lid that defines a processing space inside thereof, a gas distribution plate disposed in the processing space and connected to the chamber body, a substrate support disposed in the processing space, a first electrode embedded in the substrate support, a power supply connected to the first electrode, an electrode filter disposed between the first electrode and the power supply, a first inductor connected 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 being connected to the power supply, and a first capacitor in parallel with the second inductor An electrode filter comprising An apparatus comprising.

7. A first grounding path connected to the electrode filter between the second inductor and the third inductor, the first grounding path including a second capacitor, and A second grounding path connected to the electrode filter between the third inductor and the resistor, the second grounding path including a third capacitor The apparatus according to claim 6, further comprising.

8. The apparatus according to claim 6, wherein the first electrode comprises a conductive mesh.

9. A second electrode embedded in the substrate support, A high-frequency (RF) source connected to the second electrode, An impedance matching circuit disposed between the RF source and the second electrode The apparatus according to claim 6, further comprising.

10. The apparatus according to claim 9, wherein the first electrode is disposed between the second electrode and the surface of the substrate support facing the gas distribution plate.

11. A chamber body, a lid defining a processing space therein, A gas distribution plate disposed in the processing space and positioned adjacent to the lid, A substrate support disposed in the processing space, A first electrode embedded in the substrate support, A second electrode embedded in the substrate support between the first electrode and the surface of the substrate support facing the lid, A high-frequency (RF) source connected to the first electrode, An impedance matching circuit disposed between the RF source and the first electrode, A power supply connected to the second electrode, An electrode filter disposed between the second electrode and the power supply, wherein 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 being connected to the power supply, A first capacitor in parallel with the second inductor, A first grounding path connected to the electrode filter between the second inductor and the third inductor, the first grounding path including a second capacitor, and A second grounding path connected to the electrode filter between the third inductor and the resistor, the second grounding path including a third capacitor, An electrode filter including An apparatus comprising.

12. The apparatus according to claim 11, wherein the second electrode comprises a conductive mesh.

13. The apparatus according to claim 11, wherein the second electrode generates an electrostatic force on the surface of the substrate support.

14. The impedance matching circuit A fourth capacitor, An inductor in series with the first inductor, A grounding path upstream of the first capacitor, the grounding path including a fifth capacitor The apparatus according to claim 11, comprising.

15. The apparatus according to claim 14, wherein the fourth capacitor and the fifth capacitor are variable capacitors.

Images