阅读说明：本技术 衬底处理方法和设备
(Substrate processing method and apparatus
) 是由 吴玉伦
J·库德拉
卡尔·A·索伦森
苏希尔·安瓦尔 于 2018-06-29 设计创作，主要内容包括：提供了一种处理衬底上的材料层的方法。所述方法包括：通过匹配网络将RF功率从RF电源输送到电容耦合等离子体腔室的喷头；点燃所述电容耦合等离子体腔室内的等离子体；相对于所述RF功率的基本频率的相位测量所述RF功率的一个或多个谐波信号的一个或多个相位角；以及基于一个或多个相位角测量来相对于所述RF功率的所述基本频率的所述相位调整所述RF功率的至少一个谐波信号的至少一个相位角。(A method of processing a material layer on a substrate is provided. The method comprises the following steps: delivering RF power from an RF power source to a showerhead of a capacitively coupled plasma chamber through a matching network; igniting a plasma within the capacitively-coupled plasma chamber; measuring one or more phase angles of one or more harmonic signals of the RF power relative to a phase of a fundamental frequency of the RF power; and adjusting at least one phase angle of at least one harmonic signal of the RF power relative to the phase of the fundamental frequency of the RF power based on one or more phase angle measurements.)
1. A method of processing a material layer on a substrate, comprising:
delivering RF power from an RF power source to a showerhead through a matching network to ignite a plasma within a processing region of a capacitively-coupled plasma chamber, wherein delivering RF power comprises:
measuring one or more phase angles of one or more harmonic signals of the delivered RF power relative to a phase of a fundamental frequency of the delivered RF power; and
adjusting at least one phase angle of at least one harmonic signal of the delivered RF power relative to the phase of the fundamental frequency of the delivered RF power based on one or more phase angle measurements.
2. The method of claim 1, wherein the at least one phase angle adjusted is a phase angle of a second harmonic signal or a third harmonic signal of the delivered RF power.
3. The method of claim 1, wherein adjusting the at least one phase angle of the at least one harmonic signal of the delivered RF power relative to the phase of the fundamental frequency of the delivered RF power is further based on a particular layer of material being processed.
4. The method of claim 1, wherein the at least one phase angle is adjusted by modifying capacitance or inductance in the matching network.
5. The method of claim 1, further comprising matching an impedance of the RF power supply to an impedance of an RF load, wherein the impedance matching is performed separately from adjusting the at least one phase angle of the at least one harmonic signal.
6. The method of claim 1, wherein the at least one phase angle is adjusted by modifying at least one inductance and at least two capacitances in the matching network.
7. The method of claim 1, wherein the at least one phase angle is adjusted by modifying at least one capacitance and at least two inductances in the matching network.
8. The method of claim 1, wherein the at least one harmonic phase is adjusted without modifying a total impedance of the RF power supply that matches an impedance of an RF load, wherein the RF load comprises an ignited plasma.
9. A method of processing a material layer on a substrate, comprising:
delivering RF power from an RF power source to a showerhead through a matching network to ignite a plasma in a capacitively-coupled plasma chamber, wherein delivering RF power comprises:
measuring one or more phase angles of one or more harmonic signals of the delivered RF power relative to a phase of a fundamental frequency of the delivered RF power; and
adjusting an impedance of at least one electronic component in the matching network based on one or more phase angle measurements.
10. The method of claim 9, wherein the impedance of the at least one electronic component is adjusted based on a phase angle measurement of a second harmonic signal of the delivered RF power.
11. The method of claim 9, wherein the impedance of the at least one electronic component is adjusted based on a phase angle measurement of a third harmonic signal of the delivered RF power.
12. The method of claim 9, wherein the adjusting the impedance of at least one electronic component comprises modifying at least one inductance and at least two capacitances in the matching network.
13. The method of claim 9, wherein the adjusting the impedance of at least one electronic component comprises modifying at least one capacitance and at least two inductances in the matching network.
14. The method of claim 9, wherein the adjusting at least one impedance comprises modifying an impedance of at least three electronic components without modifying a total impedance of the RF power supply that matches an impedance of an RF load, wherein the RF load comprises the ignited plasma.
15. A method of processing a material layer on a substrate, comprising:
delivering RF power from an RF power source to a showerhead through a matching network to ignite a plasma in a capacitively-coupled plasma chamber, wherein delivering RF power comprises:
measuring a phase angle of the reflected RF power relative to a phase of a fundamental frequency of the delivered RF power; and
adjusting a phase angle of the reflected RF power relative to the phase of the fundamental frequency of the delivered RF power based on a phase angle measurement of the reflected RF power.
Technical Field
Embodiments of the present disclosure generally relate to an apparatus and method for processing a substrate in a processing chamber using plasma.
Background
Disclosure of Invention
Embodiments of the present disclosure generally relate to a plasma processing apparatus and a method of using a plasma processing apparatus, and in one embodiment, a method of processing a material layer on a substrate is provided. The method comprises the following steps: delivering RF power from an RF power source to a showerhead of a capacitively coupled plasma chamber through a matching network; igniting a plasma within the capacitively-coupled plasma chamber; measuring one or more phase angles of one or more harmonic signals of the RF power relative to a phase of a fundamental frequency of the RF power; and adjusting at least one phase angle of at least one harmonic signal of the RF power relative to the phase of the fundamental frequency of the RF power based on one or more phase angle measurements.
In another embodiment, a method of processing a material layer on a substrate is provided. The method comprises the following steps: delivering RF power from an RF power source to a showerhead of a capacitively coupled plasma chamber through a matching network; igniting a plasma within the capacitively-coupled plasma chamber; measuring one or more phase angles of one or more harmonic signals of the RF power relative to a phase of a fundamental frequency of the RF power; and adjusting an impedance of at least one electronic component in the matching network based on the one or more phase angle measurements.
In another embodiment, a method of processing a material layer on a substrate is provided. The method comprises the following steps: delivering RF power from an RF power source to a showerhead of a capacitively coupled plasma chamber through a matching network; igniting a plasma within the capacitively-coupled plasma chamber; measuring a phase angle of the reflected RF power relative to a phase of a fundamental frequency of the delivered RF power; and adjusting a phase angle of the reflected RF power relative to the phase of the fundamental frequency of the delivered RF power based on a phase angle measurement of the reflected RF power.
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, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure 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 cross-sectional view of a PECVD apparatus according to one embodiment.
FIG. 2A illustrates a matching network using a pi network configuration, according to one embodiment.
Fig. 2B illustrates a matching network using a T-network configuration, according to one embodiment.
Fig. 2C shows a matching network using a conventional L-network configuration.
FIG. 3 is a process flow diagram of a method for processing a material layer on a substrate by adjusting a phase angle of at least one signal of RF power delivered to a chamber in the PECVD apparatus of FIG. 1, in accordance with one embodiment.
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 disclosed in one embodiment may be beneficially utilized on other embodiments without further recitation. Unless specifically noted, the drawings referred to herein should not be understood as being drawn to scale. Also, the drawings are generally simplified and details or components are omitted for clarity of illustration and explanation. The drawings and discussion are intended to explain the principles of the discussion below, wherein like reference numerals refer to like elements.
Detailed Description
Embodiments of the present disclosure include a method and apparatus for improving plasma processing results within a chamber of a processing system and/or for reducing plasma process results from within-system or between-system variations of chambers by compensating for non-linear loads present in similarly configured plasma processing chambers present within the processing system. Fig. 1 shows an example of a processing system below.
FIG. 1 is a schematic cross-sectional view of a PECVD apparatus 100 according to one embodiment. The apparatus 100 includes a chamber 101 in which one or more layers of material may be processed (e.g., deposited or etched) on a substrate 120. The chamber 101 generally includes walls 102, a bottom 104, and a showerhead 106 that together define a process volume 105. A substrate support 118 is disposed within the process volume 105. The process volume 105 is accessed through the slit valve opening 108 so that the substrate 120 may be transferred into and out of the chamber 101. The substrate support 118 may be coupled to the actuator 116 to raise and lower the substrate support 118. Lift pins 122 are movably disposed through the substrate support 118 to move the substrate to and from the substrate receiving surface of the substrate support 118. The substrate support 118 may also include heating and/or cooling elements 124 to maintain the substrate support 118 at a desired temperature. The substrate support 118 may also include an RF return strap 126 to provide an RF return path to the chamber bottom 104 or wall 102 at the perimeter of the substrate support 118, which may be connected to electrical ground.
The showerhead 106 is coupled to the backing plate 112 by one or more fastening mechanisms 150 to help prevent sagging and/or control the straightness/curvature of the showerhead 106. In one embodiment, twelve fastening mechanisms 150 may be used to couple the showerhead 106 to the backing plate 112.
A gas source 132 is coupled to the backing plate 112 through a gas conduit 156 to provide gas to the processing region between the showerhead 106 and the substrate 120 through gas passages in the showerhead 106. A vacuum pump 110 is coupled to the chamber 101 to control the process volume at a desired pressure. The RF power source 128 is coupled to the backing plate 112 and/or directly to the showerhead 106 through a matching network 190 to provide RF power to the showerhead 106. The RF power generates an electric field between the showerhead 106 and the substrate support 118 such that a plasma may be generated from a gas disposed between the showerhead 106 and the substrate support 118. The substrate support 118 may be connected to electrical ground. Various frequencies may be used, such as frequencies between about 0.3MHz and about 200 MHz. In one embodiment, the RF power is provided at a frequency from about 12.88MHz to about 14.24MHz, such as 13.56 MHz.
In some embodiments, a remote plasma source 130 (such as an inductively coupled remote plasma source 130) may also be coupled between the gas source 132 and the backing plate 112. During processing of the substrate, a cleaning gas may be provided to the remote plasma source 130 so that a remote plasma is generated. Radicals from the remote plasma may be provided to the chamber 101 to clean chamber 101 components. The cleaning gas may be further energized by an RF power supply 128 provided to the showerhead 106. Suitable cleaning gases include, but are not limited to, NF3、F2、SF6And Cl2. The spacing between the top surface of the substrate 120 and the showerhead 106 may be between about 400 mils and about 1,200 mils. In one embodiment, the spacing may be between about 400 mils and about 800 mils.
The showerhead 106 may additionally be coupled to the backing plate 112 by a showerhead suspension 134. In one embodiment, showerhead suspension 134 is a flexible metal skirt. The showerhead hanger 134 may have a lip 136 on which the showerhead 106 may rest. The backing plate 112 may rest on an upper surface of a protrusion 114 coupled with the chamber wall 102 to seal the chamber 101. The chamber lid 152 may be coupled to the chamber walls 102 and spaced apart from the backing plate 112 by a region 154. In one embodiment, the region 154 may be an open space (e.g., a gap between the chamber wall and the backing plate 112). In another embodiment, region 154 may be an electrically insulating material. The chamber lid 152 may have openings therethrough to permit one or more fasteners 142 to couple with the backing plate 112 and the gas supply conduit 156 to supply the process gas to the chamber 101.
In one embodiment, the support ring 144 may be substantially centered within the opening of the chamber lid 152. The support ring 144 may be coupled to the backing plate 112 by one or more fasteners 142. RF return plate 146 may be coupled with ring 144 and chamber lid 152. The RF return plate 146 may be coupled with a chamber lid 152 by a fastening mechanism 148. An RF return plate 146 may be coupled between the fastener 142 and the ring 144. The RF return plate 146 provides a return path to the RF power source 128 for any RF current that may travel down the fastener 142 to the ring 144. The RF return plate 146 provides a path for RF power to flow back down the chamber lid 152 and then back to the RF power source 128.
PECVD apparatus 100 further comprises a system controller 50. The system controller 50 is used to control the operation of the processes performed with the PECVD apparatus 100, including the delivery of RF power from the RF power source 128 to the showerhead 106. The system controller 50 is generally designed to facilitate control and automation of the chamber 101, and may communicate with various sensors, actuators, and other devices associated with the chamber 101 through wired or wireless connections. The system controller 50 typically includes a Central Processing Unit (CPU) (not shown), memory (not shown), and support circuits (or I/O) (not shown). The CPU may be one of any form of computer processor used in an industrial environment for controlling various system functions, substrate movement, chamber processing, and control support hardware (e.g., sensors, internal and external robots, motors, gas flow control, etc.) and monitoring processes performed in the system (e.g., RF power measurements, chamber process times, I/O signals, etc.). The memory is connected to the CPU and may be one or more of readily available memory such as Random Access Memory (RAM), Read Only Memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and software data may be encoded and stored in memory for instruction to the CPU. The support circuits are also connected to the CPU for supporting the processor in a conventional manner. The support circuits may include cache, power supplies, clock circuits, input/output circuits, subsystems, and the like. A program (or computer instructions) readable by the system controller 50 determines the tasks that can be performed on the substrates in the process chamber 101. Preferably, the program is software readable by the system controller 60 that includes code for performing tasks related to monitoring, execution, and control of the movement, support, and/or positioning of the substrate, as well as various process recipe tasks (e.g., inspection operations, process environment control) and various chamber process recipe operations performed in the process chamber 101.
In order to efficiently deliver RF power to the process gases disposed within the process volume 105 of the process chamber to generate and maintain an RF plasma, the matching network 190 is used to match the impedance of the RF power supply 128 to the load (i.e., the plasma formed within the process volume). When the impedance of the RF power supply 128 does not match the load, a portion of the RF energy from the RF power supply is reflected back to the RF power supply. These reflections reduce the efficiency of the RF power delivered to the plasma and, if large enough, can interfere with the RF signal from the RF power supply 128, destabilize the RF power supply 128, or damage components in the circuitry that provides the RF power to the chamber 101.
RF plasma is an example of a non-linear load, and the non-linear load causes harmonics of the RF current and RF voltage signals to be generated at multiples of the fundamental frequency of the RF signal. For example, the second harmonic signal appears at twice the frequency (e.g., 27.12MHz) of the fundamental frequency (e.g., 13.56MHz) supplied by the RF power supply 128. The non-linear effects produced by the non-linear load will tend to distort the RF voltage and RF current waveforms within each cycle of the generated RF waveform, which has been found to have a significant effect on the plasma processing results on the substrate. It is generally believed that controlling the phase angle of these harmonic signals, such as the phase angle of the second and third order harmonics, and the phase angle of any reflected RF power at the fundamental frequency relative to the fundamental frequency of the RF power can help facilitate consistent and uniform substrate processing of a given layer of material, and that control of the phase angle can be useful for facilitating large substrates (such as having greater than about 1 m)2Such as greater than about 10m2A substrate of a surface area to be processed (e.g., deposited) is particularly useful. The phase angle of these harmonic signals or reflected RF power relative to the fundamental frequency may be controlled during processing by adjusting various components in the matching network 190, such as variable capacitors and/or variable inductors in the matching network 190. Variations in the length of the RF cable from the RF power supply 128 can also be used to adjust these phase angles, but this generally does not address most substrate manufacturing facilitiesA practical solution to this problem in substrate processing chambers in which the chamber support member is not positioned in the processing chamber, particularly in process chambers for large substrates.
Fig. 2A and 2B illustrate different circuit configurations of the matching network 190 shown in fig. 1. FIG. 2A illustrates a matching network 190A using a pi network configuration, according to one embodiment. Matching network 190A includes a variable inductor 191A, a first variable capacitor 192A, and a second variable capacitor 193A. The three electronic components 191A-193A of the pi-network configuration provide an additional degree of freedom relative to conventional L-network configurations commonly used today for impedance matching.
Fig. 2C shows a matching network 190C using a conventional L-network configuration. Matching network 190C includes a variable inductor 191C and a first variable capacitor 192C. Variable inductor 191C is electrically connected between RF power source 128 and an electrode, such as showerhead 106. The first variable capacitor 192C is electrically connected between the RF power source 128 and an electrical ground on the RF load side of the variable inductor 191C (i.e., the showerhead 106). For impedance matching in an L-network configuration, only one set of capacitance and inductance values is used to match a given load impedance at a given radio frequency. Although it is possible to rearrange an L-network configuration in which the positions of inductors and capacitors are switched, or in which a ground component (e.g., variable capacitor 192C in fig. 2C) is connected on the RF power supply side rather than the RF load side, there will still be only one set of capacitance and inductance values to match a given load impedance at a given radio frequency.
In contrast, the additional degrees of freedom provided by the pi-network configuration of fig. 2A and the T-network configuration described below with reference to fig. 2B, each including three electronic components (e.g., one inductor and two capacitors), allow an infinite number of solutions (i.e., capacitance and inductance values) for matching a given impedance at a selected radio frequency. This additional degree of freedom allows for actively matching the source and load impedances through the use of corresponding matching networks 190A, 190B, while also allowing for separately adjusting and/or controlling the phase angle, such as the phase angle of harmonic signals relative to the fundamental frequency of the RF power.
Referring to FIG. 2A, a variable inductor 191A is electrically connected between the RF power source 128 and the showerhead 106. The first variable capacitor 192A is electrically connected between the RF power source 128 and the electrical ground on the RF power source 128 side of the variable inductor 191A. The second variable capacitor 193A is arranged in parallel with the first variable capacitor 192A and is electrically connected between the RF power source 128 and the electrical ground on the RF load (i.e., showerhead 106) side connected to the variable inductor 191A. In an alternative pi-network configuration, variable inductor 191A may be replaced with a variable capacitor, and variable capacitors 192A, 193A may be replaced with variable inductors.
Since the π network configuration present in the matching network 190A has three electronic components 191A-193A, the phase angle of the harmonic signals may be adjusted, while also being adjusted to match the impedance of the RF power supply 128 to the impedance of the RF load (i.e., the plasma). Typically, the impedance matching of the formed circuit is controlled separately from the phase angle of the harmonic signal. For example, various combinations of inductance and capacitance settings of the corresponding electronic components 191A-193A may result in the same impedance of the RF power supply 128, but these different combinations may bring the ability to control the phase angle of one or more of the harmonic signals (e.g., second and third order harmonic signals) relative to the fundamental frequency of the RF power supply when the source impedance and load impedance match. Controlling the phase angle of one or more harmonic signals (e.g., second and third order harmonic signals) relative to the fundamental frequency facilitates uniform and consistent results for processing a particular material layer (e.g., silicon nitride layer deposition) in a plasma chamber, such as chamber 101 shown in fig. 1. In some embodiments using matching network 190A, phase angle controlled impedance matching in conjunction with one or more of the harmonic signals is accomplished by modifying at least one capacitance and/or at least one inductance in matching network 190A at a given set of process conditions (e.g., RF power magnitude, RF power frequency, process volume temperature and pressure, gas flow rate and composition, and the particular material layer to be processed). In other embodiments using the matching network 190A, phase angle controlled impedance matching in conjunction with one or more of the harmonic signals is accomplished by modifying at least two capacitances and at least one inductance in the matching network 190A under a given set of process conditions. The matching network 190A may also be used to control the phase angle of the reflected RF power at a given impedance mismatch between the RF power source and the load (i.e., plasma) under a given set of process conditions.
Once the desired process results are obtained on a particular apparatus (e.g., PECVD apparatus 100) used to process a particular material layer (e.g., silicon nitride deposition), the particular material layer may be repeatedly processed with the particular apparatus using the same process conditions, wherein the process conditions of the repeated process further include a phase angle of one or more harmonic signals of RF power or a phase angle of reflected RF power relative to a fundamental frequency of RF power. Using the same process conditions including the phase angles described above may help achieve consistent, uniform, and desirable process results when treating a particular material layer in a process chamber or in two or more similarly configured process chambers.
Fig. 2B illustrates a matching network 190B using a T-network configuration, according to one embodiment. Matching network 190B includes a first variable inductor 191B, a second variable inductor 192B, and a variable capacitor 193B. Similar to the pi-network configuration described above with reference to fig. 2A, the three electronic components 191B-193B of the T-network configuration provide an additional degree of freedom relative to conventional L-network configurations typically used for impedance matching. This additional degree of freedom allows matching of the source and load impedances, while also allowing adjustment and/or control of the phase angle, such as the phase angle of the harmonic signal relative to the fundamental frequency of the RF power.
The first variable inductor 191B and the second variable inductor 192B are arranged in series between the RF power source 128 and the showerhead 106. The first variable inductor 191B is disposed between the RF power source 128 and the second variable inductor 192B. The second variable inductor 192B is disposed between the first variable inductor 191B and the showerhead 106. Variable capacitor 193B is connected to electrical ground between first variable inductor 191B and second variable inductor 192B. In an alternative T-network configuration, the second variable inductor 192B may be replaced with a variable capacitor.
Since the T-network configuration present in matching network 190B has three electronic components 191B-193B, the phase angle of the harmonic signals can be adjusted, while also adjusting to match the impedance of the RF power supply 128 to the impedance of the RF load (i.e., plasma). For example, various combinations of inductance and capacitance settings of the corresponding electronic components 191B-193B may result in the same impedance of the RF power supply 128, but these different combinations may bring the ability to control the phase angle of one or more of the harmonic signals (e.g., second and third order harmonic signals) relative to the fundamental frequency of the RF power supply when the source impedance and load impedance match. Controlling the phase angle of one or more harmonic signals (e.g., second and third order harmonic signals) relative to the fundamental frequency facilitates uniform and consistent results for processing a particular material layer (e.g., silicon nitride layer deposition) in a plasma chamber, such as chamber 101 shown in fig. 1. In some embodiments using matching network 190B, phase angle controlled impedance matching in conjunction with one or more of the harmonic signals is accomplished by modifying at least one capacitance and at least one inductance in matching network 190B at a given set of process conditions (e.g., RF power magnitude, RF power frequency, process volume temperature and pressure, gas flow rate and composition, and the particular material layer to be processed). In other embodiments using matching network 190B, phase angle controlled impedance matching in conjunction with one or more of the harmonic signals is accomplished by modifying at least one capacitance and at least two inductances in matching network 190B under a given set of process conditions. The matching network 190B may also be used to control the phase angle of the reflected RF power at a given impedance mismatch between the RF power supply and the load (i.e., plasma) under a given set of process conditions.
Once the desired process results are obtained on a particular apparatus (e.g., PECVD apparatus 100) used to process a particular material layer (e.g., silicon nitride deposition), the particular material layer may be repeatedly processed with the particular apparatus using the same process conditions, wherein the process conditions of the repeated process further include a phase angle of one or more harmonic signals of RF power or a phase angle of reflected RF power relative to a fundamental frequency of RF power. Using the same process conditions including the phase angles described above may help achieve consistent, uniform, and desirable results when treating a particular material layer in a process chamber or in two or more similarly configured process chambers.
FIG. 3 is a process flow diagram of a method 1000 for processing a material layer on a substrate by adjusting a phase angle of at least one signal of RF power delivered to a chamber 101 in the PECVD apparatus 100 of FIG. 1 in accordance with one embodiment. To simplify the discussion of the method steps that occur in method 1000, the following discussion has been written such that any of the network configurations described with reference to fig. 2A and 2B may be used. However, since a pi-network typically has a low impedance at high frequencies and a T-network has a high impedance at high frequencies, selection between matching network 190A and matching network 190B may be based on the desired fundamental frequency used during RF plasma processing. Referring to fig. 1, 2A, 2B, and 3, a method 1000 is described.
At block 1002, RF power is delivered from the RF power supply 128 to the showerhead 106 of the capacitively coupled plasma chamber 101 through a matching network (e.g., the matching network 190A of fig. 2A or the matching network 190B of fig. 2B). At block 1004, a plasma is then ignited in the capacitively coupled plasma chamber 101 by the RF power supplied in block 1002.
At block 1005, the controller 50 adjusts at least one of the three electronic components (e.g., components 191A-193A or components 191B-193B) present in the corresponding matching network 190A, 190B to match the RF power supply 128 and the load impedance to achieve the desired forward and reflected RF power.
At block 1006, one or more phase angles of one or more harmonic signals (e.g., second and third order harmonic signals) of the RF power are measured relative to a fundamental frequency of the RF power. In some implementations, the phase angle measurement can include a measurement of the phase angle of the reflected RF power relative to the fundamental frequency of the RF power.
At block 1008, one or more phase angles of one or more harmonic signals (e.g., second and third order harmonic signals) of the RF power are adjusted relative to a fundamental frequency of the RF power based on the one or more phase angle measurements and the layer of material being processed (e.g., silicon nitride deposition). The phase angle of one or more harmonic signals may be adjusted relative to the phase of the fundamental frequency of the RF power while maintaining the impedance of the RF power source 128 constant using the methods described above with reference to fig. 2A and 2B. For example, an operator of the PECVD apparatus 100 may observe that when the impedances are matched and the phase angle of the second order harmonic signal is shifted by 20 degrees from the phase of the fundamental frequency, the desired uniform and homogeneous processing results may be obtained for plasma enhanced chemical vapor deposition of a silicon nitride layer. The operator and/or system controller 50 may then adjust one or more capacitance values and/or one or more inductance values of one or more of the electronic components in a matching network, such as the matching networks 190A and 190B of fig. 2A and 2B, respectively, to match the source and load impedances and control the phase angle of the second harmonic signal to be shifted from the phase of the fundamental frequency to 20 degrees. Further, the phase angle shift of one or more of the harmonic signals may also depend on the operating RF power magnitude (e.g., 1000 watts) and the frequency of the RF power (e.g., 13.56 MHz).
In implementations where the phase angle of the reflected RF power is measured in block 1006, the phase angle of the reflected RF power may be adjusted relative to the phase of the fundamental frequency of the RF power.
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.
