阅读说明：本技术 射频静电卡盘滤波器电路 (Radio frequency electrostatic chuck filter circuit ) 是由 Z·J·叶 E·海伍德 A·菲施巴赫 T·J·富兰克林 于 2020-02-17 设计创作，主要内容包括：本文描述的实施例涉及用于实质减低通过卡紧电极的射频(RF)耦合的发生的设备和方法。卡紧电极设置在定位于基板支撑件上的静电卡盘中。基板支撑件耦合至工艺腔室主体。RF源用于在与基板支撑件相邻的工艺容积中产生等离子体。阻抗匹配电路设置在RF源和设置在静电卡盘中的卡紧电极之间。静电卡盘滤波器耦合在卡紧电极与卡紧功率源之间。(Embodiments described herein relate to apparatus and methods for substantially reducing the occurrence of Radio Frequency (RF) coupling through chucking electrodes. The chucking electrode is disposed in an electrostatic chuck positioned on the substrate support. The substrate support is coupled to the process chamber body. The RF source is used to generate a plasma in a process volume adjacent to the substrate support. An impedance matching circuit is disposed between the RF source and a chucking electrode disposed in the electrostatic chuck. The electrostatic chuck filter is coupled between the chucking electrode and a chucking power source.)

1. An apparatus, comprising:

a chamber body and a lid defining a process volume therein;

a substrate support disposed in the process volume;

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; and

an electrode filter disposed between and coupled to the second electrode and the power source.

2. The apparatus of claim 1, wherein the electrode filter comprises:

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.

3. The apparatus of claim 2, wherein the second electrode comprises a conductive mesh.

4. The apparatus of claim 1, further comprising:

a gas distribution plate coupled to the chamber body and disposed relative to the substrate support.

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

6. An apparatus, comprising:

a chamber body and a lid defining a process volume therein;

a gas distribution plate disposed in the process volume and coupled to the chamber body;

a substrate support disposed in the process volume;

a first electrode embedded in the substrate support;

a power source coupled to the first electrode; and

an electrode filter disposed between the first electrode and the power source, the electrode filter comprising:

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; and

a first capacitor in parallel with the second inductor.

7. The apparatus of claim 6, further comprising:

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.

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

9. The apparatus as set forth in claim 6, wherein,

a second electrode embedded in the substrate support;

a Radio Frequency (RF) source coupled to the second electrode; and

an impedance matching circuit disposed between the RF source and the second electrode.

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

11. An apparatus, comprising:

a chamber body and a lid defining a process volume therein;

a gas distribution plate disposed in the process volume and positioned adjacent to the lid;

a substrate support disposed in the process volume;

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 facing 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; and

an electrode filter disposed between the second electrode and the power source, the electrode filter comprising:

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.

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

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

14. The apparatus of claim 11, wherein the impedance matching circuit comprises:

a fourth capacitor;

an inductor in series with the first capacitor; and

a ground path upstream of the first capacitor, the ground path including a fifth capacitor.

15. The apparatus of claim 14, wherein the fourth and fifth capacitors are variable capacitors.

Technical Field

Embodiments of the present disclosure relate generally to semiconductor processing and, more particularly, to apparatus and methods for generating and controlling radio frequency plasma for thin film deposition.

Background

In the manufacture of integrated circuits, deposition processes, such as Chemical Vapor Deposition (CVD), are commonly used to deposit films of various materials on substrates. For example, in Plasma Enhanced Chemical Vapor Deposition (PECVD), electromagnetic energy is applied to at least one precursor gas or vapor to generate a plasma.

In some examples, the electromagnetic energy used to generate the plasma may be Radio Frequency (RF) power. However, when RF power is used, capacitive coupling occurs between the plasma and the chucking electrode in the electrostatic chuck. Capacitive coupling results in RF coupling that induces high RF voltages and currents on and through the chucking electrode, which results in power loss and damage to the power supply of the chucking electrode.

Accordingly, there is a need for improved apparatus and methods for RF power application.

Disclosure of Invention

In one embodiment, an apparatus is provided that includes a chamber body and a lid defining a process volume in the chamber body and the lid. A substrate support is disposed in the process volume. A first electrode is embedded in 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 first electrode. A second electrode is embedded in 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.

In another embodiment, an apparatus is provided that includes a chamber body and a lid defining a process volume therein. A gas distribution plate is disposed in the process volume and positioned adjacent to the lid. A substrate support is disposed in the process volume. A first electrode is embedded in 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 in 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. A second inductor is disposed in series with the first inductor. A third inductor is provided in series with the first inductor and the second inductor. A set resistor is 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 provided in parallel with the second inductor.

In yet another embodiment, an apparatus is provided that includes a chamber body and a lid defining a process volume in the chamber body and the lid. A gas distribution plate is disposed in the process volume and positioned adjacent to the lid. A substrate support is disposed in the process volume. A first electrode is embedded in the substrate support. A second electrode is embedded in 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 circuit 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 is 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 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.

Drawings

So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure may be had by reference to embodiments, some of which are illustrated in the appended drawings, which are briefly summarized above. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1 is a schematic view of a process chamber according to one embodiment.

Fig. 2A is a schematic representation of a filter circuit according to one embodiment.

FIG. 2B is a schematic representation of a filter circuit according to one embodiment.

Fig. 3 is a schematic representation of an impedance matching circuit according to one embodiment.

Fig. 4 is a plan view of a cluster tool apparatus according to one embodiment described herein.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

Detailed Description

Embodiments described herein relate to apparatus and methods for substantially reducing the occurrence of Radio Frequency (RF) coupling through chucking electrodes. The chucking electrode is disposed in a substrate support coupled to the process chamber body. The RF source is used to generate a plasma in a process volume adjacent to the substrate support. An impedance matching circuit is disposed between the RF source and a chucking electrode disposed in the substrate support. To reduce damage to the chucking electrode and the chucking power source coupled thereto, an electrostatic chuck filter is coupled between the chucking electrode and the chucking power source.

FIG. 1 is a schematic view of a process chamber 100 according to one embodiment. The process chamber 100 includes a chamber body 102 and a lid 104, the chamber body 102 and lid 104 defining a process volume 120 within the chamber body 102 and lid 104. The substrate support 114 and the gas distribution plate 108 are disposed in the process volume 120. The substrate support 114 is supported within the chamber body 102 via the 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 orthogonal 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.

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

The upper surface 116 of the electrostatic chuck 115 may have a plurality of raised portions (not shown) formed thereon. The raised portions may contact a substrate (not shown) disposed on the upper surface 116 of the electrostatic chuck 115. A gas may flow 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 temperature may be controlled, for example, via a heat exchanger.

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. A plurality of holes 112 are distributed across the gas distribution plate 108 to facilitate the flow of process gases into the process volume 120.

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

The electrode 118 is embedded in the substrate support 114. Radio Frequency (RF) power is supplied to electrode 118 via RF source 134. An RF source 134 is coupled to the electrode 118 via an impedance match circuit 136. The RF source 134 can simultaneously provide RF power to the electrode 118 at one or more frequencies. For example, the RF source 134 provides RF power to the electrode at a frequency of about 13.56MHz and a frequency of about 40 MHz. To this end, 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 may include any number of frequency generators for each frequency used. The characteristic impedance of the RF source 134 is approximately 50 ohms.

The impedance match circuit 136 is capable of striking and sustaining a plasma in the process volume 120. Impedance matching circuit 136 combines the RF signals of various frequencies from RF source 134. The impedance matching circuit 136 sends the combined RF signal to the electrode 118 embedded in the electrostatic chuck 115. The combined RF signal is transmitted to the process gas in the process volume 120 to generate a capacitively coupled plasma therein. The chamber body 102 is coupled to ground and provides an RF return path to facilitate the generation of a capacitively coupled plasma.

In one embodiment, the RF power provided to the electrode 118 is between about 5kW and about 15kW, such as between about 8kW and about 13kW, for example, about 10 kW. The RF current supplied to electrode 118 is between about 120 amps and about 80 amps, such as about 110 amps. The high RF current is achieved by the relatively low resistance of the impedance matching circuit 136, which is between about 0.2 ohms and about 0.4 ohms. The voltage delivered to the electrode 118 is between about 8kV and about 13kV, such as about 10 kV. The impedance matching circuit 136 has an impedance angle between about 85 degrees and about 90 degrees, for example, between about 87 degrees and about 89 degrees.

The electrode 122 is a component of an electrostatic chuck 115 disposed on the substrate support 114. A dielectric layer (not shown) may be disposed on the electrostatic chuck 115 and 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 one 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 electrodes 122.

The coupling capacitance of electrode 122 is between about 800pF and about 2500 pF. In one embodiment, which may be combined with one or more of the embodiments described above, the electrode 122 is made of an aluminum-containing material. In one embodiment, which 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.

When a plasma is generated in the process volume 120, RF current enters the electrode 122 and flows to the power supply 132 (e.g., RF leakage). RF current entering and flowing through power supply 132 may damage power supply 132, which may result in a loss of power to the electrodes 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 placed between the power supply 132 and the electrode 122.

The filter circuit 130, such as an RF filter, substantially prevents RF current from flowing to the power supply 132. Thus, the filter circuit 130 substantially reduces the occurrence of damaging 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 so that minimal current is transferred from the substrate and plasma. However, the impedance of the filter circuit 130 is low enough to substantially prevent current from flowing to the power supply 132.

A controller 124 is coupled to the process chamber 100 to control various aspects of the processing performed therein. For example, the controller 124 controls the flow rate of the process gas from the gas delivery system 126 to the process volume 120. The controller 124 may also control aspects of loading and unloading substrates from the process chamber 100. In addition, the controller 124 may control aspects of the impedance matching circuit 136 and the filter circuit 130, such as the capacitance of the variable capacitor.

Fig. 2A is a schematic representation of a filter circuit 200 according to one embodiment. The filter circuit 200 may correspond to the filter circuit 130 described above with respect to fig. 1. 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 provided in series with the first inductor 202. A third inductor 210 is provided in series with the first inductor 202 and the second inductor 206. A resistor 214 is provided in series with the first inductor 202, the second inductor 206 and the third inductor 210. Resistor 214 is coupled to a power source, such as power supply 132 shown in FIG. 1.

A first capacitor 204 is placed in parallel with a second inductor 206. The first capacitor 204 and the second inductor 206 form an L-C resonant circuit. The first ground path includes a second capacitor 208, the second capacitor 208 being coupled to the filter circuit 200 between the second inductor 206 and a third inductor 210, and to ground. The second ground path includes a third capacitor 212, the third capacitor 212 being coupled to the filter circuit 200 between the third inductor 210 and the resistor 214, and to ground. The second capacitor 208 and the third capacitor 212 are shunt (shunt) capacitors coupled to ground.

The first part 231 of the filter circuit comprises a first inductor 202, a second inductor 206 and a first capacitor 204. The first part 231 is the inductive part of the filter circuit 200. Most of the RF current entering the filter circuit 200 at 13.56MHz is removed by the first inductor 202. Similarly, most of the 40MHz RF current is removed by the L-C resonant circuit including the second inductor 206 and the first capacitor 204.

The second part 233 of the filter circuit 200 is a low pass filter comprising a second capacitor 208, a third inductor 210 and a third capacitor 212. Resistor 214 is an optional current limiting resistor between second portion 233 and the power supply. The second portion 233 removes any remaining RF current from the filter circuit 200 to prevent RF current from leaking into the power supply connected to the resistor 214.

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) may be tuned based on one or more frequencies of RF current flowing therebetween. For example, in one embodiment that may be combined with one or more of the embodiments described above, first inductor 202 has an inductance from about 14 μ H to about 25 μ H, such as about 20 μ H, third inductor 210 has an inductance from about 8 μ H to about 13 μ H, such as about 10 μ H, second capacitor 208 and third capacitor 212 have an inductance from about 800pF to about 15000pF, such as about 1000pF, and the resistor has a resistance from about 1 Ω to about 5 Ω, such as about 2 Ω.

The L-C resonant circuit (including the first capacitor 204 and the second inductor 206) may have a resonant frequency of 40 MHz. The values of the components (e.g., first inductor 202, second inductor 206, and first capacitor 204) in first portion 231 may be based on an input frequency of 13.56 MHz. That is, the first portion 231 may be designed to remove the RF current at a frequency of 13.56 MHz.

Advantageously, the filter circuit 200 shown in FIG. 2A substantially reduces the RF current flowing from the electrode 122 shown in FIG. 1 to the power supply 132. Thus, the filter circuit 200 substantially reduces the extent and incidence of damaging power supplies.

Fig. 2B is a schematic representation of a filter circuit 270 according to one embodiment. The filter circuit 270 may correspond to the filter circuit 130 described above with respect to fig. 1. That is, filter circuit 270 may be an alternative design to filter circuit 200 described above with respect to fig. 2A.

The filter circuit 270 includes a first portion 260 and a second portion 262. The first section 260 includes a first inductor bank 230 and a second inductor bank 232 in series. The second section 262 includes the capacitor bank 234, the third inductor bank 236, and the shunt capacitor 254. Capacitor bank 234 is connected in parallel with shunt capacitor 254. As shown, the first inductor group 230 includes four parallel inductors 240a, 240b, 240c, and 240 d. The second inductor bank 232 includes four parallel inductors 242a, 242b, 242c, and 242 d. The first portion 260 of the filter circuit 270 has a combined inductance of 20 muh.

As shown, the second portion 262 of the filter circuit 270 is a low pass filter. Capacitor bank 234 includes four capacitors 246, 248, 250, and 252. The third inductor group includes three inductors 244a, 244b, and 244c in parallel. The capacitance of each capacitor 246, 248, 250, 252, and 254 is 1000 pF. The inductance of the third inductor bank 236 is about 10 muh. The values of the components of the filter circuit 270 may be tuned based on the one or more input frequencies to be removed by the filter circuit 270.

Fig. 3 is a schematic representation 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. The 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 process chamber, such as the process chamber 100 described above with respect to fig. 1.

Fig. 4 is a plan view of a cluster tool apparatus 400 according to one embodiment described herein. The apparatus 400 includes a plurality of process chambers 402, 404, 406, and 408, a transfer chamber 420, and load lock chambers 410 and 412. Each process chamber 402, 404, 406, and 408 is coupled to a transfer chamber 420. Although four process chambers 402, 404, 406, and 408 are shown in fig. 4, any number of process chambers may be coupled to the transfer chamber 420.

In one embodiment, which may be combined with one or more of the embodiments described above, the process chamber 402 is disposed adjacent to the process chamber 408. In one embodiment, the process chamber 404 is disposed adjacent to the process chamber 402. In one embodiment, which may be combined with one or more of the embodiments described above, the process chamber 406 is disposed adjacent to the process chamber 404. In one embodiment, which may be combined with one or more of the embodiments described above, each process chamber 402, 404, 406, and 408 corresponds to the process chamber 100 illustrated in FIG. 1.

The transfer chamber 420 enables transfer of substrates between the load lock chambers 410, 412 and the process chambers 402, 404, 406, and 408. The transfer robot 414 is disposed in the transfer chamber 420. The transfer robot 414 may be a single-blade robot or a double-blade robot. The transfer robot 414 has a substrate transfer blade 416 attached to the distal end of the extendable arm. The blade 416 is used to support and carry the individual substrates between the process chambers 402, 404, 406, and 408. The transfer chamber 420 is maintained in a vacuum or reduced oxygen environment.

A controller 430 is coupled to the device 400. The controller 430 includes a Central Processing Unit (CPU) (not shown). The controller 430 may be one of any form of a general purpose computer processor that may be used to control various process chambers and sub-processors. The controller 430 may be coupled to separate or shared controllers of the process chambers 402, 404, 406, and 408. The controller 430 may control movement of the transfer robot 414 for transferring substrates within the apparatus 400.

In one embodiment, which may be combined with one or more of the embodiments described above, adjacent process chambers (e.g., process chambers 402 and 408) have shared gas delivery systems, RF sources, controllers, and/or vacuum systems. These shared systems increase the throughput of the processes performed in the process chamber and the uniformity of the deposited films. The shared system also reduces the costs associated with the process.

Benefits of the present disclosure include filter circuits to reduce the amount of RF current (e.g., RF leakage) that propagates to and damages the DC power supply. The filter circuit enables the RF current to be directed away from the DC power supply and back to the RF source. The filter circuit also prevents the occurrence of power loss of the chucking electrode and loss of chucking force applied to the substrate.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.