KR101952563B1

KR101952563B1 - A method of controlling the switched mode ion energy distribution system

Info

Publication number: KR101952563B1
Application number: KR1020157007771A
Authority: KR
Inventors: 빅터 브룩; 다니엘 제이. 호프만; 다니엘 카터
Original assignee: 어드밴스드 에너지 인더스트리즈 인코포레이티드
Priority date: 2012-08-28
Filing date: 2013-08-26
Publication date: 2019-02-27
Also published as: CN104782233B; JP2015534718A; JP6329543B2; CN104782233A; WO2014035899A8; KR20150047599A; WO2014035899A1

Abstract

A system, method and apparatus for adjusting ion energy in a plasma chamber and chucking a substrate to a substrate support is disclosed. An exemplary method comprises the steps of placing a substrate in a plasma chamber, forming a plasma in the plasma chamber, controllably switching power to the substrate to apply a periodic voltage function (or a modified periodic voltage function) to the substrate And modulating the periodic voltage function in response to a desired ion energy distribution at the surface of the substrate over multiple cycles of the periodic voltage function to achieve a defined ion energy distribution in a time-averaged manner.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for controlling a switching mode ion energy distribution system,

This application is a continuation-of-part application (CIP) of U.S. Patent Application No. 13 / 193,299 filed on July 28, 2011 and a continuation application (CIP) of U. S. Patent Application No. 12 / 870,837 filed on Aug. 29, to be. The details of the above applications 13 / 193,299 and 12 / 870,837 are incorporated herein by reference in their entirety and for all appropriate purposes.

The present invention generally relates to plasma processing. In particular, but not by way of limitation, the invention relates to apparatus and methods for plasma-assisted etching, deposition, and / or other plasma-assisted processing.

Many types of semiconductor devices are fabricated using plasma-based etching techniques. If there is a conductor to be etched, a negative voltage with respect to ground can be applied to the conductive substrate to generate a substantially uniform negative voltage along the surface of the substrate conductor, which attracts the positively charged ions to the conductor, As a result, the cations impinging on the conductor have substantially the same energy.

However, if the substrate is a dielectric, the unchanging voltage will not apply a voltage along the surface of the substrate. However, an AC voltage (e.g., high frequency) may be applied to the conductive plate (or chuck) so that the AC electric field induces a voltage on the surface of the substrate. During 1/2 the positive period of the AC cycle, the substrate attracts electrons, which is light for the mass of the cations; Thus, many electrons will be attracted to the surface of the substrate during both cycles. As a result, the substrate surface will be negatively charged, which causes ions to be attracted toward the negatively charged surface. And when ions hit the substrate surface, this collision moves material from the surface of the substrate and causes etching.

In many instances it is preferred that the ion energy distribution be narrow, but applying a sinusoidal waveform to the substrate leads to a broad ion energy distribution, which limits the ability of the plasma processing to achieve the desired etch profile. Known techniques for achieving a narrow ion energy distribution are expensive, low in efficiency, difficult to control, and can adversely affect plasma density. As a result, these known technologies have not been commercially adopted. Thus, the systems and methods are required to provide other new and innovative features that focus on the shortcomings of the current technology.

Exemplary embodiments of the present disclosure shown in the drawings are summarized below. These and other embodiments are more fully described in the detailed description section. It should be understood, however, that there is no intent to limit the invention to the form as described in the Summary or the Detailed Description. Those skilled in the art will recognize that there are numerous variations, equivalents, and alternative constructions within the spirit and scope of the invention as expressed in the claims.

According to one embodiment, the present invention is an apparatus for providing a modified periodic voltage function to an electrical node, the electrical node configured to be coupled to a substrate support of a plasma processing chamber. The apparatus may include a power supply, an ion current compensation element, and a controller. The power supply may provide a period voltage function to the electrical node, which has a pulse and a portion between the pulses. The ion current compensation element may change the slope of the portion between the pulses to provide ion current compensation to form a modified period voltage function. The controller may be configured to communicate with the switching mode power supply (SMPS) and the ion current compensation element to identify a value of the ion current compensation that appears as a defined ion energy distribution function of ions reaching the substrate surface when supplied to the electrical node have.

According to another embodiment, the present invention is a method of providing a modified periodic voltage function to an electrical node, the electrical node configured to be electrically coupled to a substrate support of a plasma processing chamber. The method may include providing the ion node with an ion current compensation (Ic). The method may further comprise providing a periodic voltage function to the electrical node, wherein the periodic voltage function is modified by an ion current compensation (Ic) to form a modified period voltage function. The method may also include providing a modified period voltage function to the electrical node, wherein the modified period voltage function has a pulse and a portion between the pulses. The method also includes accessing an effective capacitance value (C1) indicative of a minimum capacitance of the substrate support. At the same time, the method may include determining the slope (dVo / dt) of the portion between the pulses of the modified periodic voltage function. Finally, the method may include identifying a value of the ion current compensation (Ic) that is a defined ion energy distribution function of the ions reaching the surface of the substrate, said identification being based on a slope (dVo / dt) and effective capacitance (C1).

According to yet another embodiment, the present invention can be characterized as a method comprising an applying step, a sampling step, an estimating step and an adjusting step. First, the method may include applying a modified period voltage function to the electrical node, wherein the modified period voltage function constitutes a modified period voltage function by ion current compensation. The electrical node may be configured to couple to a substrate support coupled to the substrate in a plasma processing chamber. The method may also include sampling at least one cycle of the modified period voltage function to generate a voltage data point. The method may further comprise calculating a first ion energy value for ions reaching the surface of the substrate based on a voltage data point. Finally, the method may include adjusting the modified period voltage function until the first ion energy becomes equal to the defined ion energy.

Another aspect of the present invention is a method including a providing step, a sampling step, a calculating step, a comparing step, and a adjusting step. First, the method may provide a modified period voltage function to the electrical node, wherein the electrical node is configured to be coupled to the substrate support of the plasma processing chamber. The method may also sample at least two voltages from the modified period voltage function at the first and second times. The method may also calculate the slope of at least two voltages as dV / dt. The method may also compare the slope to a known reference slope to correspond to the ion energy distribution function width. Finally, the method can adjust the modified periodic voltage function so that the slope reaches the reference slope.

Another aspect of the invention is a non-transitory, type of computer readable recording medium encoded with instructions readable by a processor to perform a method of identifying a defined ion current compensation (Ic). The method may include sampling the modified periodic voltage function when an ion current compensation (Ic) having a first value is made. Moreover, the method may include sampling the modified periodic voltage function when an ion current compensation (Ic) having a second value is made. In addition, the above method can access the effective capacity C1 for the plasma processing apparatus. Moreover, the method may determine the slope (dVo / dt) of the modified period voltage function based on the first and second sampling. Finally, the method may include calculating a third value of the ion current compensation (Ic) that makes the following equation true: < RTI ID = 0.0 >

These and other embodiments are described in further detail below.

BRIEF DESCRIPTION OF THE DRAWINGS The various objects and advantages of the present invention will become more apparent upon a reading of the following detailed description and appended claims, taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar elements throughout the several views, Reference numbers have been assigned:
Figure 1 shows a block diagram of another plasma processing system in accordance with one embodiment of the present invention;
Figure 2 is a block diagram illustrating an exemplary embodiment of the switched mode power system (SMPS) shown in Figure 1;
Figure 3 is a schematic representation of a component that may be used to implement the switching mode bias supply described with reference to Figure 2;
4 is a timing chart showing two drive signal waveforms;
5 is a graphical representation of a single mode operating a switching mode bias supply that implements concentrated ion energy distribution at a particular ion energy;
Figure 6 is a graph showing bi-modal mode operation in which two separate peaks are generated in the ion energy distribution;
Figures 7A and 7B are graphs showing actual direct ion energy measurements made in plasma, respectively;
8 is a block diagram illustrating another embodiment of the present invention;
9A is a graph showing an exemplary periodic voltage function that is modulated by a sinusoidal modulating function;
FIG. 9B is an enlarged view of a portion of the periodic voltage function shown in FIG. 9A; FIG.
Figure 9C shows the resulting ion energy distribution in a time-averaged manner resulting from sinusoidal modulation of the periodic voltage function;
Figure 9D shows the actual direct ion energy measurements made in the plasma of the resulting time-average IEDF when the periodic voltage function is modulated by a sinusoidal modulating function;
10A shows a periodic voltage function modulated by a sawtooth modulation function;
FIG. 10B is an exploded view of a portion of the period voltage function shown in FIG. 10A; FIG.
Figure 10C is a graph showing the resulting distribution of ion energy on a time-averaged basis due to sinusoidal modulation of the period voltage function in Figures 10A and 10B;
11 is a graph showing the IEDF function in the right column and the related modulation function in the left column;
12 is a block diagram illustrating an embodiment in which the ion current compensating section compensates for the ion current in the plasma chamber;
13 is a diagram illustrating an exemplary ion current compensation unit;
14 is a graph showing an example of the voltage at the node Vo shown in Fig. 13;
Figures 15A-15C are voltage waveforms that appear on the surface of a substrate or wafer in response to a compensating current;
Figure 16 is an exemplary embodiment of a current source that may be implemented to realize the current source described with reference to Figure 13;
17A and 17B are block diagrams showing another embodiment of the present invention;
18 is a block diagram showing another embodiment of the present invention;
19 is a block diagram showing another embodiment of the present invention;
20 is a block diagram of an input parameter and control output that may be utilized in connection with the embodiment described with reference to Figs. 1 to 19;
21 is a block diagram showing another embodiment of the present invention;
22 is a block diagram showing another embodiment of the present invention;
23 is a block diagram illustrating another embodiment of the present invention;
24 is a block diagram showing another embodiment of the present invention;
25 is a block diagram illustrating another embodiment of the present invention;
26 is a block diagram showing another embodiment of the present invention;
27 is a block diagram showing another embodiment of the present invention;
28 shows a method according to an embodiment of the present disclosure;
29 shows another method according to an embodiment of the present disclosure;
30 shows an embodiment of a method of controlling the ion energy distribution of ions impinging on the surface of a substrate;
31 shows a method for setting the IEDF and ion energy;
32 illustrates two modified period voltage function waveforms delivered to the substrate support in accordance with one embodiment of the present disclosure;
33 shows an ion current waveform that can indicate a change in plasma source instability or plasma density;
34 shows the ion current (I _I ) of a modified periodic voltage function waveform having a non-cyclical shape;
35 shows a modified period voltage function waveform that can indicate a failure within the bias supply;
Figure 36 shows a modified periodic voltage function waveform that can represent a dynamic change in system capacity;
Figure 37 shows a modified period voltage function waveform that can show a change in plasma density;
Figure 38 shows the sampling of the ion current for different process runs where the drift of the ion current may indicate system drift;
Figure 39 shows sampling of the ion current for different process parameters;
Figure 40 shows two bias waveforms monitored in a chamber without plasma;
Figure 41 shows two bias waveforms that can be used to confirm plasma processing;
Figure 42 shows a number of power supply voltages and ion energy plots illustrating the relationship between power supply voltage and ion energy;
Figure 43 shows an embodiment of a method of controlling the ion energy distribution of ions impinging on the surface of a substrate;
Figure 44 shows various waveforms at different points in the system described herein;
Figure 45 shows the result of a final incremental change in the ion current compensation (Ic) to match the ion current compensation (Ic) to the ion current (I _I );
46 shows the selection of ion energy;
Figure 47 shows the selection and expansion of the ion energy distribution function width;
Figure 48 shows one pattern of power supply voltages (V _PS ) that each ion energy level can be used to achieve one ion energy level or more with a narrow IEDF width;
Figure 49 shows another pattern of power supply voltage (V _PS ) that can be used to achieve one ion energy level or higher with each ion energy level having a narrow IEDF width;
Figure 50 shows one combination of the power supply voltage (V _PS ) and the ion current compensation (Ic) that can be used to generate the defined IEDF.

An exemplary embodiment of a plasma processing system is shown in FIG. As shown, a plasma power supply 102 is coupled to the plasma processing chamber 104 and a switching mode power supply 106 includes a support portion 108 in which the substrate 110 rests within the chamber 104, Lt; / RTI > Also shown is a control 112 coupled to the switching-mode power supply 106. The control-

In this exemplary embodiment, the plasma processing chamber 104 may be realized by a chamber of a substantially conventional configuration (e.g., including a vacuum enclosure ejected by a pump or pumps (not shown)). And, as is known to those of ordinary skill in the art, the plasma excitation within chamber 104 may be accomplished by any of a variety of sources including, for example, a helicon plasma source, A magnetic coil and an antenna for igniting and holding the plasma 114 in the reactor, and a gas inlet for introducing gas into the chamber 104 may be provided.

As shown, a typical plasma chamber 104 is arranged to perform plasma-assisted etching of materials utilizing a strong ion bombardment of the substrate 110 and other plasma processing (e.g., plasma deposition and plasma assisted ion implantation) Consists of. The plasma power supply 102 of this embodiment is coupled to the chamber 104 via a matching network (not shown) at more than one frequency (e.g., 13.56 MHz) to ignite and sustain the plasma 114 , RF power). The present invention is not limited to any particular type of plasma power supply 102 or source that couples power to the chamber 104 and may include various capacities or power levels that can be capacitively or inductively coupled to the plasma 1140 It should be understood.

The dielectric substrate 110 (e.g., a semiconductor wafer) to be processed as shown is supported at least partially by a support 108, which may include a portion of a conventional wafer chuck (e.g., for semiconductor wafer processing) . The support portion 108 may be formed with an insulating layer between the support portion 108 and the substrate 110 such that the substrate 110 is capacitively coupled to the platform and may be floating have.

As described above, if the substrate 110 and the support 108 are conductors, it is possible to apply a constant voltage to the support 108, and as a result of the electrical conduction through the substrate 110, The voltage applied to the surface of the substrate 110 is also applied.

However, applying a constant voltage to the support 108 when the substrate 110 is a dielectric is not effective to apply a voltage along the processed surface of the substrate 110. As a result, a voltage is applied to the surface of the substrate 110, which is capable of attracting ions to the plasma 114 such that a typical switched mode power supply 106 impinges on the substrate 110, / RTI > and / or < RTI ID = 0.0 > deposition-assisted < / RTI >

Furthermore, as discussed below, an embodiment of the switched mode power supply 106 may be implemented by a combination of power applied by the plasma power supply 102 (to the plasma 114) and power supplied by the switching mode power supply 106 to the substrate 110 so that there is no substantial interaction between them. The power applied by the switching mode power supply 106 can be controlled to enable control of the ion energy without substantially affecting the density of the plasma 114, for example.

Moreover, many embodiments of the exemplary switched mode power supply 106 shown in FIG. 1 can be realized with relatively inexpensive components that can be controlled by a relatively simple control algorithm. Compared to the conventional approach, many embodiments of the switched mode power supply 106 are more effective; This can save energy costs and expensive materials associated with eliminating excessive heat energy.

One well-known technique for applying a voltage to a dielectric substrate utilizes a high output linear amplifier associated with a complex control technique of applying a voltage to a substrate support that induces a voltage on the surface of the substrate. However, this technology has not been adopted by commercial corporations because the price is not proven effective and well manageable. In particular, the linear amplifiers used are typically large, very expensive, inefficient, and difficult to control. Moreover, linear amplifiers require an inherently AC coupling (e. G., Blocking capacitors) and ancillary functions such as chucking can be used in parallel feed circuits (feeds) that degrade the AC spectral purity of the system for sources with chucks. circuit.

Another technique that has been considered is to apply high frequency power (e.g., with one or more linear amplifiers) to the substrate. However, this technique has been confirmed to have a detrimental effect on the plasma density because the high frequency power applied to the substrate affects the plasma density.

In some embodiments, the switching mode power supply 106 shown in FIG. 1 may be realized by a buck, boost, and / or buck-boost type power technology. In these embodiments, the switched mode power supply 106 may be controlled to apply pulsed power at varying levels to induce a potential on the surface of the substrate 110.

In another embodiment, the switched mode power supply 106 may be realized by other more sophisticated switched mode power and control techniques. Referring to FIG. 2, for example, the switched mode power supply described in connection with FIG. 1 may be utilized to power the substrate 110 to realize one or more desired energies of ions impinging on the substrate 110 Mode power supply 206, which is shown in FIG. A control unit 212 coupled to the ion energy control unit 220, the arc detection unit 222 and the switching mode power supply 206 and the waveform memory 224 is also shown.

The illustrated arrangement of these components is logical; Thus, in practice, parts can be combined or further separated, and components can be connected in a variety of ways without changing the basic operation of the system. In some embodiments, the control unit 212, which may be implemented, for example, by hardware, software, firmware, or a combination thereof, may be utilized to control both the power supply 202 and the switched mode power supply 206. However, in other embodiments, the power supply 202 and the switched mode power supply 206 may be realized by completely separate functional units. As an alternative, the controller 212, the waveform memory 224, the ion energy control 220 and the switching mode bias supply 206 may be integrated within a single component (e. G., Within a common housing) Can be distributed.

The switching mode bias supply 206 of this embodiment is entirely configured to apply a voltage to the support 208 in a controllable manner to achieve a desired (or defined) distribution of the energy of the ions impinging on the surface of the substrate. More specifically, the switching mode bias supply 206 is configured to achieve a desired (or defined) distribution of ion energy by applying one or more specific waveforms of a particular power level to the substrate. More specifically, in response to an input from the ion energy control 220, the switching mode bias supply 206 applies a particular power level to achieve a specific ion energy and supplies the waveform memory 224 with one or more voltages Use a waveform to apply a specific power level. As a result, one or more specific ion impact energy can be selected by the ion control to realize controlled etching (or other types of plasma processing) of the substrate.

As shown, the switched mode power supply 206 includes switching elements 226 and 226 (e.g., switching elements) that are adapted to switch power to the support portion 208 of the substrate 210 in response to a drive signal from a corresponding drive portion 228,228 , High output FET). The driving signals 230 and 230 generated by the driving units 228 and 228 are controlled by the control unit 212 based on the timing defined by the contents of the waveform memory 224. For example, in many embodiments, the controller 212 interprets the contents of the waveform memory to generate drive control signals 232 and 232, which are utilized by the drivers 228 and 228 to drive the switching elements 226 and 226, And the drive signals 232, Although two switching elements 226 and 226 arranged in a half-bridge configuration are shown for illustrative purposes, it is not certain that fewer or additional switching elements can be implemented in various configurations (e.g., an H-bridge configuration) . In many operating modes, the controller 212 (e.g., using waveform data) modulates the timing of the drive control signals 232, 232 to achieve the desired waveform on the support 208 of the substrate 210. Furthermore, the switching mode bias supply 206 is adapted to supply power to the substrate 210 based on an ion-energy control signal 234, which may be a DC signal or a time-varying waveform. Thus, this embodiment enables control of the ion distribution energy by controlling the timing signal for the switching member and controlling the power applied by the switching members 226, 226 (controlled by the ion energy control 220) .

The control unit 212 of this embodiment is configured to execute an arc management function in response to an arc detected in the plasma chamber 204 by the arc detection unit 222. [ In some embodiments, when an arc is detected, the controller 212 changes the drive control signals 232, 232 to cause the waveform applied to the output 236 of the switching mode bias supply 206 to extinguish the arc at the plasma 214. In an alternative embodiment, the control 212 extinguishes the arc by simply interrupting the application of the drive control signals 232, 232 so that the power application to the output 236 of the switching mode bias supply 206 is interrupted.

Referring now to FIG. 3, there is shown a schematic diagram of components that may be utilized to realize the switching mode bias supply 206 described with reference to FIG. As shown in the figure, in this embodiment, the switching members T1 and T2 are arranged in a half-bridge configuration (also called a totem pole). Collectively, R2, R3, C1 and C2 represent the plasma load, C1O is the effective capacitance (hereinafter referred to as the series capacitance or the chuck capacitance), C3 is the DC current from the voltage induced on the surface of the substrate It is also a selectable physical capacitor that prevents DC current from flowing from the voltage of an electrostatic chuck (not shown) flowing through the circuit. C1O is referred to as the effective capacitance because it includes the series capacitance (also referred to as the chuck capacitance) of the substrate support and the electrostatic chuck (or e-chuck) as well as other capacitors inherent in the application of bias as an insulator and substrate. As shown, L1 is the stray inductance (e.g., the natural inductance of the conductor that powers the load). And in this embodiment there are three inputs: Vbus, V2 and V3.

V2 and V4 represent driving signals (e.g., driving signals 230 'and 230 " output by the driving units 228 and 228 described with reference to FIG. 2, (E.g., a pulse and / or a length of mutual delay) may be adjusted so that the closing of T2 is modulated to control the shape of the voltage output Vout applied to the substrate support. In many embodiments, T1, T2) is not an ideal switch to reach the desired waveform and transistor-specific characteristics are taken into account. In many modes of operation, simply changing the timing of V2 and V4 Doing so causes the desired waveform to be applied to Vout.

For example, the switches T1, T2 may be operated such that the voltage on the surface of the substrate 110, 210 is a periodic voltage pulse approaching and / or slightly exceeding the positive voltage reference and is generally negative. The voltage value of the surface of the substrate 110, 210 defines the energy of the ions and can be characterized by the expression of the ion energy distribution function (IEDF). In order to achieve the desired voltage on the surface of the substrates 110 and 210, the pulses at Vout are generally rectangular and have a sufficiently long width to induce short positive voltages on the surfaces of the substrates 110 and 210, Lt; RTI ID = 0.0 > 110 < / RTI >

A periodic voltage pulse approaching and / or slightly exceeding the positive voltage reference may have a minimum time defined by the switching capability of the switches T1, T2. As a whole, the voltage at the negative portion can be extended unless the voltage reaches a level that compromises the switch. At the same time, the length of the voltage in the sound field must exceed the ion transit time.

In this embodiment, Vbus defines the amplitude of the pulse measured at Vout, which defines the voltage on the substrate surface, and ultimately the ion energy. Referring briefly to FIG. 2 again, Vbus may be coupled to the ion energy control, which may be realized by a DC power supply adapted to apply a DC signal or a time-varying waveform to the Vbus.

The pulse width, pulse shape and / or mutual delay of the two signals V2 and V4 can be modulated to reach a desired waveform at Vout (also referred to herein as a modified period voltage function) It can affect the characteristics. Upon reduction, the voltage Vbus affects the pulse width, pulse shape and / or relative phase of the signals V2 and V4. Referring briefly to FIG. 4, a timing diagram illustrating two drive signal waveforms that may be applied to T1 and T2 (V2, V4) to generate a periodic voltage function at Vout, as shown, for example, . The timing of the two gate drive signals (V2, V4) is controlled to modulate the shape of the pulse at Vout (e.g., to achieve the smallest time for the pulse at Vout, which has already reached the peak value of the pulse) .

For example, the time for which each pulse is applied at Vout may be short compared to the time T between pulses, but the positive voltage on the surface of the substrate 110, 210 to attract electrons to the surface of the substrate 110, The two gate drive signals V2 and V4 may be applied to the switching elements T1 and T2 to be sufficiently long to induce the switching elements T1 and T2. Moreover, it is possible to control the slope of the voltage applied to Vout between pulses by changing the gate voltage level between the pulses (e.g., achieving a substantially constant voltage across the surface of the substrate between pulses) It was announced. In some modes of operation, the repetition rate of the gate pulse is about 400kHz, but this repetition rate can certainly vary depending on the application.

A waveform that may be used to generate the desired (or defined) ion energy distribution may be defined based on modeling and refinement of the actual embodiment, although it is not actually required, and the waveform may be defined (e.g., In the waveform memory section described with reference to Fig. 1). Also, in many implementations the waveform can be generated directly (e.g., without feedback from Vout); Thus, an undesirable aspect of the feedback control system (e.g., settling time) can be avoided.

Referring again to FIG. 3, Vbus may be modulated to control the energy of the ions and the stored waveform may be used to control the gate drive signals (V2, V4) to minimize the desired pulse amplitude to Vout . This can also be done according to the particular characteristics of the transistor, which can be modeled or executed and set empirically. Referring to FIG. 5, for example, a graph representing Vbus vs. time, surface voltage versus time of the substrate 110, 210, and corresponding ion energy distribution is shown.

The graph of FIG. 5 represents a single mode of operation of the switching mode bias supplies 106, 206, which achieves a concentrated ion energy distribution at a particular ion energy. As shown, in this example, the voltage applied to Vbus is kept constant to achieve a single concentration of ion energy while the voltage applied to V2 and V4 is controlled to produce a pulse at the output of switching mode bias supplies 106, (E.g., using the drive signal shown in Figure 3), which achieves the corresponding ion energy distribution shown in Figure 5.

As shown in FIG. 5, the potential of the surface of the substrate 110, 210 collides with the surface of the substrate 110, 210 and becomes negative as a whole so as to attract etching ions. The periodic short pulses applied to the substrates 110 and 210 (by applying a pulse to Vbus) have a magnitude defined by the potential applied to Vbus, and these pulses are applied to the substrate 110 and 210 by a simple change , Close to a positive or slightly positive potential), which attracts electrons to the surface of the substrate to achieve an overall negative potential along the surface of the substrate 110, 210. As shown in Figure 5, a constant voltage applied to Vbus achieves a single concentration of ion flux with a specific ion energy; Thus, the specific ion bombardment energy can be selected by simply setting Vbus to a specific potential. In another mode of operation, two or more separate concentrations of ion energy may be created (see, e.g., FIG. 49).

Those skilled in the art will appreciate that the power supply need not be limited to a switched mode power supply, and the output of the power supply can also be controlled to affect any ion energy. The power supply output itself, whether in a switching mode or not, is also referred to as the power supply voltage (VPS) when considered without being associated with ion current compensation or ion current.

Referring to FIG. 6, a graph is shown illustrating, for example, bi-modal mode operation where two separate peaks are generated in the ion energy distribution. As shown, in this mode of operation, the substrate experiences two distinct levels of voltage and periodic pulses, resulting in two separate concentrations of ion energy. As shown, the voltage applied to Vbus to achieve two distinct ion energy concentrations travels between two levels, each level defining an energy level of two ion energy concentrations.

Although this figure is not necessarily required, even if two voltages appear alternately after every pulse on the substrate 110, 210 (e.g., Figure 48). In operation of the other modes, for example, the voltages applied to V2 and V4 are switched relative to the voltage applied to Vout (e.g., using the drive signal shown in Figure 3) The induced voltage changes from the first voltage to the second voltage (and vice versa) after two or more pulses (Figure 49).

Attempts have been made in the prior art to apply a combination of two waveforms (generated by waveform generators) to a linear amplifier to achieve multi-ion energy and to apply an amplified combination of two waveforms to the substrate. However, this approach requires more complex and expensive linear amplifiers and waveform generators than the approach described with reference to FIG.

Referring to Figures 7A and 7B, there is shown a graph showing the actual direct ion energy measurements made in the plasma corresponding to a single energy and dual level adjustment of the DC voltage applied to Vbus, respectively. As shown in FIG. 7A, the ion energy distribution is concentrated near 80 eV in response to the application of a voltage that does not change to Vbus (e. G., As shown in FIG. 5). And two separate concentrations of ion energy are present near 85 eV and 115 eV in response to a dual level adjustment of Vbus (e.g., as shown in Figure 6), as in Figure 7b.

Referring now to Figure 8, a block diagram illustrating another embodiment of the present invention is shown. The switching mode power supply 806 is coupled to the substrate support 808 via the control unit 812, the ion energy control unit 820 and the arc detection unit 822 as shown. The control unit 812, the switched mode power supply 806 and the ion energy control unit 820 together operate to apply power to the substrate support 808 and apply a desired Lt; / RTI > ion energy distribution.

Referring briefly to FIG. 9A, a periodic voltage function having a frequency of 400 kHz is shown, which is modulated, for example, by a sinusoidal modulation function of about 5 kHz over multiple cycles of the period voltage function. FIG. 9B is an exploded view of a part of the periodic voltage function indicated by a circle in FIG. 9A, and FIG. 9C shows a resultant distribution of ion energy in a time-averaged manner due to sinusoidal modulation of the periodic voltage function. And Figure 9d shows the actual direct ion energy measurements made on the resulting plasma of time-averaged IEDF when the periodic voltage function is modulated by a sinusoidal modulation function. As discussed further herein, achieving the desired (or defined) ion energy distribution in a time-averaged manner can be achieved by simply changing the modulation function applied to the periodic voltage.

Referring to Figs. 10A and 10B, as another example, the 400 kHz periodic voltage function is modulated by a sawtooth modulation function of about 5 kHz to reach the distribution of ion energy shown in Fig. 10C in a time-averaged manner. As shown, the periodic voltage function used in connection with FIG. 10 is the same as FIG. 9 except that the periodic voltage function in FIG. 10 is modulated by a sawtooth function instead of a sinusoidal function.

It should be appreciated that the ion energy distribution function shown in Figures 9c and 10c does not represent an instantaneous distribution of the ion energy of the surface of the substrate 810, but instead represents a time average of the ion energy. Referring to FIG. 9c, for example, the distribution of ion energy at a particular moment in time is a subset that represents the distribution of ion energy present during the full cycle of the modulation function.

It should be appreciated that the modulation function does not have to be a fixed function and does not have to be a fixed frequency. In some cases, for example, after modulating a periodic voltage function having one or more cycles of a particular modulation function to achieve a particular time-average ion energy distribution, one or more of the other modulation functions may be used to achieve a different time- It is desirable to modulate the periodic voltage function with cycles. This change to the modulation function (which modulates the periodic voltage function) is beneficial in many cases. For example, if a particular distribution of ion energy is required to etch a particular geometric configuration or to etch through a particular material, a first modulation function is used and then another modulation function continues to achieve another etch structure Can be used to etch other materials.

Similarly, the periodic voltage function (e.g., the 400 kHz component of Figures 9a, 9b, 10a, 10b and Vout of Figure 4) need not be tightly fixed (e.g., But its frequency as a whole is set by the running time of the ions in the chamber so that the ions of the chamber are affected by the voltage applied to the substrate 810. [

8, control 812 provides drive control signals 832 ', 832 " to switching mode power supply 806 so that switching mode power supply 806 generates a period voltage function. The power supply 806 can be realized by the components shown in Fig. 3 (to generate the period voltage function shown in Fig. 4), but it is certainly expected that other switching schemes can be used.

In general, the ion energy controller 820 serves to apply a modulation function to the periodic voltage function (generated by the controller 812 in conjunction with the switching mode power supply 806). 8, the ion energy control unit 820 includes a customized IEDF unit 850, an IEDF function memory 848, a user interface 846, and a modulation control unit 840 that communicates with the power unit 844, . It should be appreciated that the description of these components may in fact be intended to refer to functional components that may be achieved by common or other components.

In this embodiment, the modulation control unit 840 generally controls the power unit 844 (and its output 834) based on the data defining the modulation function, and the power unit 844 controls the switching mode power supply 806 A modulation function 834 (based on the control signal 842 from the modulation control unit 840) applied to the periodic voltage function generated by the modulation circuit 840 is generated. In this embodiment, the user interface 846 is configured to enable the user to select a predetermined IEDF function stored in the IEDF function memory 848, or to define a custom IEDF with respect to the custom IEDF portion 840.

In many implementations, the power section 844 includes a DC power supply (e.g., a DC switched mode power supply or a linear amplifier) that is coupled to a switching mode power supply (e. G., The switching mode power To the Vbus of the supply) a modulation function (e.g., a varying DC voltage). In these implementations, the modulation control unit 840 controls the voltage level output by the power unit 844 such that the power unit 844 applies a voltage that is compliant with the modulation function.

In some implementations, the IEDF function memory 848 includes a plurality of data sets corresponding to each of the plurality of IEDF distribution functions, and the user interface 846 allows the user to select a desired (or defined) IEDF function . Referring to FIG. 11, for example, an exemplary IEDF function that can be selected by the user in the right column is shown. The left column shows the associated modulation function that the modulation control unit 840 associated with the power unit 844 applies to the periodic voltage function to achieve the corresponding IEDF function. It should be appreciated that the IEDF function shown in FIG. 11 is merely exemplary and other IEDF functions may be used for selection.

The custom IEDF portion 850 generally functions through the user interface 846 to define a user desired (or defined) ion energy distribution function. In some implementations, the custom IEDF portion 850 allows the user to set a value for a particular parameter that defines the distribution of ion energy.

For example, the custom IEDF portion 850 may be configured to allow the IEDF function to be set to a high level (IF-high), a middle-level (IF-mid), and a low level ) To be defined in terms of the relative level of the flux (e.g., as a percentage of the flux). In many instances only IF-high, IF-low and the IEDF function between these levels are sufficient to define the IEDF function. As a specific example, the user requires 1200 eV at a 20% distribution level (contribution to total IEDF) and 700 eV at a 30% contribution level with a sine wave IEDF between these two levels.

Custom IEDF portion 850 should also be considered to allow the user to add a table with a list of one or more (e.g., multiple) energy levels and a corresponding percentage contribution of each energy level to IEDF. And in another embodiment custom IEDF portion 850 associated with user interface 846 may provide a graphical tool that allows the user to select the desired (or defined) IEDF, It is also conceivable to make the IEDF graphically generated.

Furthermore, the IEDF function memory 848 and the custom IEDF unit 850 are also considered to generate a custom IEDF function derived from a predetermined IEDF function by allowing a user to modify a predetermined IEDF function after selecting a predetermined IEDF function .

Once the IEDF function is defined, the modulation control unit 840 interprets the data defining the desired (or defined) IEDF function as a control signal 842 that controls the power unit 844, Achieves a modulation function corresponding to the desired (or defined) IEDF function. For example, the control signal 842 controls the power section 844 and the power section 844 outputs the voltage defined by the modulation function.

12, a block diagram illustrating an embodiment in which the ion current compensating section 1260 compensates the ion current in the plasma chamber 1204 is shown. Applicants have discovered that at higher energy levels, a higher level of ion current inside the chamber affects the surface voltage of the substrate, and as a result the ion energy distribution is also affected. Referring briefly to Figures 15A-15C, their relationship to voltage waveform and IEDF appearing on the surface of the substrate 1210 or wafer is shown.

More specifically, FIG. 15A shows the periodic voltage function at the surface of the substrate 1210 when the ion current I _I is equal to the compensation current Ic; 15B shows a voltage waveform on the surface of the substrate 1210 when the ion current I _I is greater than the compensation current Ic; 15C shows the voltage waveform on the surface of the substrate 1210 when the ion current I _I is less than the compensation current Ic.

As shown in FIG. 15A, the spread of ion energy 1470 when I _I = Ic is equal to the spread of ion energy 1470 at I _I > Ic as shown in FIG. 1472) or relatively uniform (1474) of ion energy 1470 at _I < Ic as shown in FIG. 15C. Accordingly, the ion current compensating section 1260 narrows the diffusion of the ion energy when the ion current is high (for example, by compensating the influence of the ion current), and the ion current compensating section 1260 also has a constant ion Allowing diffusion of energy 1572,1574 to be controlled (e.g., when it is desirable to have diffusion of ion energy).

As shown in FIG. 15B, the voltage of the substrate surface between positive portions of the periodic voltage function without ion current compensation (when I &_gt; Ic) is almost negative in a ramped manner, (1572). Similarly, the ion current compensation is used to increase the level of the compensation current at a level (I _I < Ic) above the ion current as shown in FIG. 15C, And a wider diffusion 1574 of constant ion energy is generated.

Referring again to FIG. 12, the ion current compensation unit 1260 can be realized as a separate accessory that can be selectively added to the switching mode power supply 1206 and the control unit 1212. In another embodiment (e.g., as shown in FIG. 13), the ion current compensating section 1260 may include other components described herein (e.g., switching mode power supplies 106,206,806,1206) (220, 820) and a common housing (1366). The periodic voltage function provided in the plasma chamber 1204 in this embodiment can be referred to as a modified periodic voltage function since it is constituted by the periodic voltage function changed by the ionic current compensation from the ionic current compensation unit 1260. [ The control unit 1212 can sample the voltage at different times to the electrical node to which the output of the switching mode power supply 1206 and the output of the ion current compensation unit 1260 are coupled.

An exemplary current source 1364 coupled to the output 1336 of the switched mode power supply and a current controller 1362 coupled to both the current source 1364 and the output 1336, And an ion current compensation section 1360 is shown. Also shown in FIG. 13 is a plasma chamber 1304, in which the capacitive elements C1 and C2 and the ion current I _I are shown. As shown, C1 represents the inherent capacitance of a component associated with chamber 1304 (and is subsequently referred to as the effective capacitance), and chamber 1304 includes, but is not limited to, an insulator, a substrate, a substrate support, and e - chuck (e-chuck), and C2 represents the sheath capacity and stray capacity. The periodic voltage function provided in the plasma chamber 1304 in this embodiment and measurable in Vo is referred to as a modified periodic voltage function because it constitutes a periodic voltage function that is modified by the ionic current compensation Ic.

A sheath (also referred to herein as a plasma sheath) is a layer in the plasma near the substrate surface and in all the walls of the plasma processing chamber filled with high positive cations and thus a large positive charge over the entire surface. The surface that the sheath touches is typically predominantly negative. The sheath is generated by electrons at a faster rate than the cations, thus allowing a larger fraction of electrons to reach the substrate surface or wall, thus depleting the electrons. Sheath thickness _(sheath) is a function of the plasma characteristics such as plasma density and plasma temperature.

Note that in this embodiment C1 is not an accessible capacity added to control the process because it is a unique (and also referred to herein as effective) capacity of the components associated with chamber 1304. [ For example, some prior art approaches using a linear amplifier couple the bias power to the substrate to a blocking capacitor and then use the monitored voltage across the blocking capacitor as a feedback to control the linear amplifier. Although the capacitors incorporate a switching mode power supply in the substrate support in many of the embodiments disclosed herein, it is unnecessary to do so because feedback control using a blocking capacitor is not required in some embodiments of the present invention.

Referring to Fig. 13, at the same time, referring to Fig. 14, a graph showing an exemplary voltage (e.g., a modified period voltage function) at Vo shown in Fig. 13 is shown. In operation, the current controller 1362 monitors the voltage at Vo and the ion current is calculated according to the following equation (1) according to the interval t (shown in FIG. 14): < EMI ID =

The ion current (I _I ) and the intrinsic capacity (also referred to as effective capacity) Cl can either be varied or may vary with time. C1 is substantially constant and measurable for a given tool, and Vo is required to be monitored to enable progressive control of the compensation current. As described above, in order to obtain a distribution of more single energy of ion energy (such as that shown in FIG. 15A), the current controller is configured so that Ic is substantially equal to I _I (or, in a variant, To control the current source 1364. [ In this way, a narrow width of ion energy can be maintained even when the ion current reaches a level that affects the voltage on the substrate surface. Moreover, if desired, the width of the ion energy can be controlled as shown in Figs. 15B and 15C so that additional ion energy is realized at the substrate surface.

Also shown in Fig. 13 is a feedback line 1370 that may be used in connection with controlling the ion energy distribution. For example, the value of DELTA V shown in FIG. 14 (also referred to herein as voltage step or third portion 1406) represents instantaneous ion energy and can be used in many embodiments as part of a feedback control loop. In one embodiment, the voltage step? V is related to the ion energy according to equation (4). In another embodiment, the peak-to-peak voltage ( _Vpp ) may be related to the instantaneous ion energy. In another example, the difference between the peak-to-peak voltage (V _pp ) and the product of the slope (dVo / dt) of the fourth portion 1408 and the time t is correlated with the instantaneous ion energy , V _pp -dVo / dtt).

Referring now to FIG. 16, there is shown an exemplary embodiment of a current source 1664 that may be implemented to realize the current source 1364 described with reference to FIG. A controllable negative DC voltage source associated with the series inductor L2 in this embodiment serves as a current source, but one of ordinary skill in the art will recognize that the current source may be realized with other components and / I will understand the point.

Figure 43 shows an embodiment of a method for controlling the ion energy distribution of ions impinging on the surface of a substrate. The method 4300 begins by applying a modified periodic voltage function 4302 (see the correction period voltage function 4302 in FIG. 44) to a substrate support that supports the substrate inside the plasma processing chamber. The modified period voltage function is controlled through at least two knobs such as an ion current compensation Ic (see Ic 4404 in FIG. 44) and a power supply voltage Vps (see power supply voltage in FIG. 44) . An exemplary component for generating a power supply voltage is the switched mode power supply 106 in FIG. Are shown here as if they were measured without coupling to the ion current and ion current compensation to help explain the power supply voltage (Vps). The modified period voltage function is then sampled to the first and second values of the ion current compensation 4304. At least two sample voltages of the modified period voltage function are taken for each value of the ion current compensation (Ic). Sampling 4304 is performed to enable computation 4306 (or determination) of the ion current I _I and the sheath capacitance C _sheath 4306. This crystal may include finding an ion current compensation (Ic) that produces a narrow (e.g. minimum) ion energy distribution function (IEDF) width when applied to the substrate support (or applied to the substrate support) have. Calculation 4306 also includes determining a voltage step? V (also known as a third portion of the modified period voltage function 1406) based on the sampling 4304 of the waveform of the optionally modified period voltage function . The voltage step? V may be related to the ion energy of the ions reaching the surface of the substrate. When the ion current I _I is found for the first time, the voltage step? V can be ignored. Details of sampling 4304 and calculation 4306 will be provided in the following description of FIG.

Once the ion current (I _I ) and sheath capacity (C _sheath ) are known, the method 4300 includes setting and monitoring the shape (e.g., width) of the ion energy and the IEDF, . &Lt; / RTI > For example, Figure 46 shows how a change in power supply voltage can affect the change in ion energy. In particular, as the magnitude of the power supply voltage shown decreases, the magnitude of the ion energy also decreases. Furthermore, FIG. 47 shows that for narrow IEDF 4714, IEDF can be widened by regulating the ion current compensation (Ic). Alternatively or in parallel, the method 4300 may use various metrics that use different aspects of the waveform of the ion current (I _I ), sheath capacitance (C _sheath ), and modified period voltage function as described with reference to Figures _32-41 Can be executed.

In addition to setting the ion energy and / or the IEDF width, the method 4300 can adjust the waveform 4308 of the modified period voltage function to maintain ion energy and IEDF width. In particular, adjustment of the ion current compensation (Ic) provided by the ion current compensating unit and adjustment of the power supply voltage are performed at 4308. [ In some embodiments, the power supply voltage may be controlled by the bus voltage (Vbus) of the power supply (e.g., bus voltage (Vbus) in Figure 3). The ion current compensation (Ic) controls the IEDF width and the power supply voltage controls the ion energy.

These adjustments (4308) has changed since the period is a voltage function to the re-sampling performed in 4304, the ionic current (I _I), system capacity (C _sheath) and the staff voltage (V) may be carried out again in 4306. The ion current compensation Ic and / or power supply voltage may be adjusted at 4308 if the ion current I _I or the voltage step V is different from the defined value (or alternate desired value). Looping of sampling 4304, computation 4306 and adjustment 4308 may occur to maintain ion energy (eV) and / or IEDF width.

30 shows another embodiment of a method for controlling the ion energy distribution of ions impinging on the surface of a substrate. As described above in some embodiments, it is desirable to achieve a narrow IEDF width (e.g., a minimum IEDF width or substantially ~ 6% half full width). Thus, the method 3000 can provide a modified period voltage function to the chamber and substrate support such that there is a constant substrate voltage on the surface of the substrate and therefore a sheathed voltage exists. This ultimately accelerates the ions at both ends of the sheath with a substantially constant voltage, thus causing the ions to collide with the substrate having substantially the same ion energy to provide an alternately narrow IEDF width. For example, adjusting the ion current compensation Ic in FIG. 45 allows the substrate voltage Vsub between the pulses to have a constant or substantially constant voltage, thus narrowing the IEDF.

This modified cycle voltage function, ion current compensation (Ic) is achieved when the same as the ion current (I _I), assuming that there is no stray capacitance (see the last 5 cycles of a periodic voltage function (Vo) in Fig. 45) . If an _stray capacitance (C _stray ) is considered in the alternative, the ion current compensation (Ic) is related to the ion current (I _I ) according to the following equation:

Here, C ₁ is the effective capacitance (for example, the intrinsic capacitance described with reference to FIGS. 3 and 13). The effective capacitance C15 varies with time or is constant. For the purposes of this disclosure, a narrow IEDF width may exist when I _I = Ic or when equation (2) is satisfied. 45 to 50 use the nomenclature, I _I = Ic, but these equivalences are only a simplification of equation (2), so that equation (2) can be substituted for the equivalence used in FIGS. 45 to 50 Should be understood. The stray capacitance (C _stray ) is the cumulative capacitance of the plasma chamber as shown by the power supply. There are eight cycles in FIG.

The method 3000 can be used to calculate a modified period voltage function (e.g., the modified period voltage function shown in Figure 14 or the modified period voltage function 4402 shown in Figure 44) Substrate support 108). &Lt; / RTI > The voltage of the modified periodic voltage function is sampled at 2 or more 3004 and the slope dVo / dt for a portion of at least one cycle of the modified period voltage function from this sampling (e.g., 4 slope of portion 1408) may be calculated at 3006. < RTI ID = 0.0 > The predetermined value of the effective capacity C1 (for example, the intrinsic capacity C1 of FIG. 13 and the intrinsic capacity C10 of FIG. 3) at the point before the decision 3010 is 3008 From the user input). The function f can be evaluated for each value of the ion current compensation Ic according to the following equation (3) based on the slope dVo / dt, the effective capacitance C1 and the ion current compensation Ic:

If the function f is true, the ion current compensation Ic is the same as the ion current I _I , or alternatively, see Equation 2 and the narrow IEDF width 3010 (see FIG. 45) . If the function f is not true, the ion current compensation Ic can be further adjusted at 3012 until the function f is true. Another way of looking at this point can be adjusted until the ion current compensation Ic is matched with the ion current I _I (in other cases when the relationship of Equation 2 is met), at which point there is a narrow IEDF width . This adjustment to the ion current compensation (Ic) and the result of narrowing the IEDF can be seen in Fig. The ion current I _I and the corresponding ion current compensation Ic may be stored in the storage operation 3014 (e.g., in memory). The ion current compensation Ic may change with time such as the effective capacity C ₁ .

When Equation 3 is satisfied, the ion current I _I is known (because I _I = Ic or because Equation 2 is true). Thus, the method 3000 enables remote and non-local measurement of the ion current I _{I in} real time without affecting the plasma. This leads to a number of novel metrics as described with reference to Figures 32-41 (e.g., remote monitoring of plasma density and remote failure detection of plasma sources).

While adjusting the ion-compensating current (Ic) at 3012, the ion current is likely to become wider than the delta function, and the ion energy will resemble one of Fig. 15B, Fig. 15C or Fig. However, once it is confirmed that the ion-compensating current Ic satisfies the equation (2), the IEDF appears to have a narrow IEDF width (for example, the minimum IEDF width) as shown on the right side of FIG. 15A or 45 will be. This is because the voltage between the pulses of the modified periodic voltage function causes a substantially constant cis or substrate voltage and then ion energy when I _I = Ic (or alternatively when Equation 2 is true). 46, the substrate voltage 4608 includes pulses between certain voltage portions. Because these pulses are too short in duration, their effect on ion energy and IEDF can be neglected and thus the substrate voltage 4608 is said to be substantially constant.

The following provides more details of the steps of each method shown in FIG.

In one embodiment, the modified period voltage function may have a waveform as shown in FIG. 14 and may have a first portion (e.g., first portion 1402, second portion 1404, (E.g., a third portion 1406 and a fourth portion 1408), the third portion may have a voltage step? V, and the fourth portion may have a voltage step The modified period voltage function 1400 may also have a first portion 1402, a second portion 1404, a second portion 1402, a second portion 1402, A third portion 1406, and a portion between the pulses (the fourth portion 1408).

The modified period voltage function may be measured as Vo in Fig. 3 and may appear as a modified period voltage function 4402 in Fig. The modified period voltage function 4402 is generated by combining the power supply voltage 4406 (also known as the period voltage function) with the ion current compensation 4404. The power supply voltage 4406 is largely related by shaping and shaping the pulses of the modified period voltage function 4402 and by generating and shaping the portions between pulses, which are often linearly tilted voltage 4404 . Increasing the ion current compensation (Ic) reduces the slope magnitude of the portion between the pulses as shown in Fig. When the magnitude of the power supply voltage 4606 is reduced, the magnitude of the peak-to-peak voltage and the amplitude of the pulse of the modified period voltage function 4602 decreases as shown in FIG.

If the power supply is a switched mode power supply, the switching diagram 4410 of the first switch T1 and the second switch T2 may be applied. For example, the first switch T1 may be implemented as the first switch T1 in FIG. 3, and the second switch T2 may be implemented as the second switch T2 in FIG. Both switches have the same switching time but are shown to have 180 phase differences. In other embodiments, the switching may have some phase offset as shown in FIG. When the first switch T1 is ON, the power supply voltage is pulled to the maximum magnitude of the negative value in FIG. 44 because the power supply has a negative bus voltage. The second switch T2 is off during this period and the power supply voltage 4406 is isolated from ground. When switching is reversed, the power supply voltage 4406 approaches the ground and passes through some ground. In the illustrated embodiment there are two pulse widths, but this is not required. In other embodiments, the pulse width may be the same for all cycles. In other embodiments, the pulse width may be varied or may be modulated over time.

The modified periodic voltage function is applied to the substrate support 3002 so that the Vo of the last accessible point is sampled at 3004 before the modified periodic voltage function reaches the substrate support (e.g., between the switching mode power supply and the effective capacity). The unchanged periodic voltage function (or power supply voltage 4406 in FIG. 44) may be obtained from the power supply, such as switching mode power supply 1206 in FIG. The ion current compensation 4404 in Fig. 44 can be obtained from a current source such as the ion current compensation unit 1260 in Fig. 12 or 1360 in Fig.

Some or all of the modified period voltage function may be sampled at 3004. For example, a fourth portion (e.g., fourth portion 1408) may be sampled. Sampling 3004 may be performed between the power supply and the substrate support. For example, in FIG. 1, sampling 3004 may be performed between the switched mode power supply 106 and the support 108. In Fig. 3, the sampling 3004 can be performed between the inductor L1 and the intrinsic capacitance C10. In one embodiment, sampling 3004 may be performed at Vo between capacitance C3 and intrinsic capacitance C10. Sampling 3004 is typically performed on the left side of the intrinsic capacitance C10 in Fig. 3 because the elements representing the intrinsic capacitance C10 and the plasma R2, R3, C1, C2 are not accessible for real-time measurement. Although the intrinsic capacity C10 is typically not measured during processing, it is typically a known constant and can therefore be set during manufacture. At the same time, in some cases the intrinsic capacitance C10 may vary over time.

Only two samples of the modified period voltage function are needed in some embodiments, while in other embodiments hundreds, thousands or tens of thousands of samples may be taken during each cycle of the modified period voltage function. For example, the sampling rate may be at least 400 kHz. These sampling rates enable a more precise and detailed monitoring of the modified period voltage function and its shape. More detailed monitoring of the modified period voltage function in this same context enables a more precise comparison of waveforms between cycles, between different process conditions, between different treatments, between different chambers, between different sources, and so on. For example, at this sampling rate, the first through fourth portions 1402, 1404, 1406, and 1408 of the modified period voltage function shown in FIG. 14 may be distinguished, which may not be possible at a conventional sampling rate. In some embodiments, a higher sampling rate enables the decomposition of the voltage step (DELTA V) and the slope (dVo / dt), which is not possible in the prior art. In some embodiments, one portion of the modified period voltage function may be sampled while the other portion is not sampled.

Calculation 3006 of the slope dVo / dt may be based on a number of Vo measurements taken during time t (e.g., fourth portion 1408). For example, a linear fit can be performed to fit the line to the Vo value if the slope of the line provides a slope (dVo / dt). In another embodiment, a Vo value may be identified at the start and end times t (e.g., fourth portion 1408) in FIG. 14, and the line may be identified by these two points < RTI ID = 0.0 > . &Lt; / RTI > These are just two of the many ways in which the slope (dVo / dt) of the portion between the pulses can be calculated.

Decision 3010 can be part of the iterative loop used to fit the IEDF to a narrow width (e.g., a minimum width or alternatively a full width half maximum (FWHM)). Equation 3 applies only when the ion current compensation Ic is the same as the ion current I _I (or, alternatively, I _I according to Equation 2), since there is a constant substrate voltage and therefore constant And only a single ion energy (narrow IEDF width) is present. The constant substrate voltage 4608 (Vsub) can be seen in FIG. Thus, an ion current (I _I ) or, alternatively, an ion current compensation (Ic) can be used in equation (3).

Alternatively, two values along the fourth portion 1408 (also referred to as portions between pulses) may be sampled during the first cycle and the second cycle, and the first and second slopes may be determined for each cycle, respectively have. From these two slopes the ion current compensation Ic can be determined, which is expected to be true for the third slope (but not yet measured). Thus, the ion current I _I can be estimated to correspond to the narrow IEDF width. There are only two of the many ways in which a narrow IEDF width can be determined, and corresponding ion current compensation Ic and / or corresponding ion current I _I can be found.

Adjustments to the ion current compensation (Ic) 3012 may include an increase or decrease in the ion current compensation (Ic), and there is no restriction on the step size for each adjustment. In some embodiments, the sign of function (f) in equation (3) can be used to determine whether to increase or decrease the ion current compensation. If the sine is negative, the ion current compensation (Ic) is reduced, while the positive sine indicates what is required to increase the ion current compensation (Ic).

Once the ion current compensation Ic is determined to be the same as the ion current I _I (or alternatively, in accordance with Equation 2 herein), the method 3000 may be performed in a subsequent setpoint operation (see FIG. 31) And source monitoring operations (see Figures 32-41). The subsequent setpoint operation may include setting the ion energy (see also Figure 46) and the distribution of ion energy or the IEDF width (also see Figure 47). Source and chamber monitoring may include monitoring plasma density, source supply anomaly, plasma arc, and the like.

Moreover, the method 3000 may choose to return to sampling 3004 to continuously (or alternatively, periodically) update the ion current compensation Ic. For example, sampling 3004, calculation 3006, decision 3010 and adjustment 3012 may be performed periodically considering ion current compensation Ic to ensure that equation (3) continues to be met . At the same time, if the ion current compensation (Ic) satisfying the equation 3 is updated, then the ion current I _I can also be updated and the updated value can be stored at 3014.

The ion current compensation Ic required to achieve a narrow IEDF width while discovery and setting the ion current compensation Ic so that the method 3000 is equal to the ion current I _I or alternatively meets the equation (2) Can be determined without setting the ion current I _I to its value (or alternatively before setting the ion current I _I to its value). For example, during a first cycle, a first ion current compensation (Ic ₁ ) is applied and a first slope (dV ₀₁ / dt) of the voltage between pulses is measured, and during a second cycle a second ion current compensation ₂₎ is applied and by measuring a second gradient (dV ₀₂ / dt) of the voltage between pulses, and the third ion current compensation (Ic ₃₎ and the third gradient (dV ₀₃ / dt) is equation (3) associated It can be judged whether it is going to be true. The third ion current compensation (Ic ₃ ) can be one that results in a narrow IEDF width if applied. For this reason, the ion current compensation (Ic) corresponding to equation (3) and corresponding to the ion current (I _I ) can therefore be determined solely by a single adjustment of the ion current compensation. The method 3000 can then move the ionic current Ic in the manner described in Figures 31 and / or 32-41 without being always set to the value required to achieve a narrow IEDF width. This embodiment can be implemented to increase the tuning speed.

31 shows a method of setting the IEDF width and ion energy. The method may take any one of the left path 3100 (also referred to as the IEDF branch) or the right path 3101 (also referred to as the ion energy branch), starting with the method 3000 shown in FIG. 30 , Respectively, to set the IEDF width and ion energy. The ion energy eV is proportional to the voltage step? V or the third part 1406 of the modified period voltage function of Fig. The relationship between the ion energy (eV) and the voltage step (? V) can be written as:

In this case, C ₁ is the effective capacitance (for example, chuck capacitance; the intrinsic capacitance C ₁₀ in FIG. 3; or the intrinsic capacitance C ₁ in FIG. 13) and C ₂ is the sheath capacitance The sheath capacitance C4 in Fig. 3 or the sheath capacitance C2 in Fig. 13). The sheath capacitance (C ₂ ) may include stray capacitance and depends on the ion current (I _I ). The voltage step? V may be measured as a voltage change between the second portion 1404 and the fourth portion 1408 of the modified period voltage function 1400. [ The ion energy eV can be controlled and known by controlling and monitoring the voltage step? V (which is a function of the power supply voltage or the bus voltage such as the bus voltage Vbus in Fig. 3).

At the same time, the IEDF width can be approximated according to the following equation:

Where I is I _I if C is C _series and I is I _C if C is C _effective . Time t is the time between pulses, V _PP is the peak-to-peak voltage, and DELTA V is the voltage step.

In addition, the sheath capacitance (C ₂ ) can be used for various calculation and monitoring operations. For example, the Debye sheath distance ( _sheath ) can be approximated according to the following equation:

Where epsilon is the vacuum permittivity and A is the area of the substrate (or alternatively the surface area of the substrate support). In some high voltage applications, Equation 6 is expressed as Equation 7: < RTI ID = 0.0 >

Moreover, the e-field in the _sheath can be approximated as a function of _sheath capacitance C2, _sheath and ion energy eV. The sheath capacitance C ₂ according to the ion current I _I can also be calculated from Equation 8 where the saturation current I _sat is linearly related to the compensation current I _C for a single ionized plasma, _e ). < / RTI >

The effective mass of ions on the substrate surface can be calculated using the sheath capacitance (C ₂ ) and saturation current (I _sat ). The plasma density (n _e ), the electric field inside the sheath, the ion energy (eV), the effective mass of the ions and the DC potential (VDC) of the substrate (VDC) merely depend on the basic plasma parameters to be. These publications enable direct measurement of these parameters and thus enable more precise monitoring of plasma properties in real time.

As shown in equation (4), the sheath capacitance (C ₂ ) can also be used to monitor and control the ion energy (eV) as shown in the ion energy branch 3101 of FIG. The ion energy branch 3101 begins by receiving a user selection of the ion energy 3102. The ion energy branch 3101 may then set the initial power supply voltage for the switched mode power supply to provide the period voltage function 3104. [ At some point before the sample period voltage operation 3108, the ion current may also be accessed (e.g., accessed from memory) at 3106. The periodic voltage can be sampled at 3108 and the measurement of the third part of the modified periodic voltage function can be measured at 3110. [ The ion current I _I can be calculated from the voltage step? V of the modified period voltage function 3112 (also referred to as a third portion (e.g., third portion 1406)). The ion energy branch 3101 may then determine whether the ion energy is equal to the defined ion energy 3114 and if so, the ion energy is at the desired set point and the ion energy branch 3101 ends . If the ion energy is not equal to the defined ion energy, then the ion energy branch 3101 may adjust the power supply voltage 3116 and resample the period voltage 3108 again. The ion energy branch 3101 then cycles through a loop of sampling 3108, measurement 3110, calculation 3112, determination 3114 and setting 3116 until the ion energy becomes equal to the defined ion energy. do.

A method for monitoring and controlling the IEDF width is shown in FIG. 31 in the IEDF branch 3100. The IEDF branch 3100 includes a user selected reception 3150 of the IEDF width and a current IEDF width sampling 3152. The decision 3154 then determines if the defined IEDF width is equal to the current IEDF width, if the IEDF width is the same as the desired (or defined) IEDF branch 3100, do. However, if the current IEDF width is not equal to the defined IEDF width, the ion current compensation (Ic) can be adjusted at 3156. This determination 3154 and adjustment 3156 may continue in a loop-loop manner until the current IEDF width is equal to the defined IEDF width.

In some embodiments, the IEDF branch 3100 may also be implemented to secure the desired IEDF shape. Various IEDF features can be generated and each can be associated with different ion energies and IEDF widths. For example, the first IEDF shape may be a delta function and the second IEDF shape may be a square function. Other IEDF shapes may be cup-shaped. An example of the various IEDF shapes is shown in FIG.

Knowing the ion current (I _I ) and the voltage step (? V), Equation (4) can be solved for the ion energy (eV). The voltage step [Delta] V can be controlled by changing the power supply voltage, and the power supply voltage alternates the voltage step [Delta] V. The larger power supply voltage causes the voltage step (DELTA V) to increase, and the reduction of the power supply voltage causes the voltage step (DELTA V) to decrease. In short, increasing the power supply voltage increases the ion energy (eV).

Moreover, since the system and method operate on a continuously varying feedback loop, the desired (or defined) ion energy and IEDF width are maintained < RTI ID = 0.0 > .

Although Figures 30-41 are described with respect to single ion energies, those of ordinary skill in the art will understand that the method of generating and monitoring the desired (or defined) IEDF width (or IEDF shape) (Or < RTI ID = 0.0 > IEDF < / RTI > shape). For example, by providing the first power supply voltage (V _PS ) in the first, third and fifth cycles and providing the second power supply voltage in the second, fourth and sixth cycles, two different, narrow Ion energy can be achieved for ions reaching the substrate surface (e.g., FIG. 42A). Using three different power supply voltages, three different ion energies are obtained (e.g., Fig. 42B). The ion flux of different ion energies can be controlled (e. G., FIG. 42C) by varying the number of cycles during which each of the multiple power supply voltages is applied, or while each power supply voltage level is applied.

The determination may be made by combining the periodic voltage function provided by the power supply with the ion current compensation provided by the ion current compensating unit to determine the IEDF width and / or the IEDF shape of the ions reaching the surface of the substrate during ion energy and plasma processing It shows the method used to control.

Some of the controls mentioned above are made possible by a combination of the following: (1) fixed waveforms (the continuous cycles of the waveform are the same); (2) a waveform having at least two portions proportional to ion energy and IEDF (e.g., the third and fourth portions 1406 and 1408 shown in FIG. 14); And (3) a high sampling rate (e.g., 125 MHz) that allows for accurate monitoring of different features of the waveform. For example, when a conventional technique such as a linear amplifier sends a waveform to a substrate similar to a modified period voltage function, an undesired change between cycles may result in these conventional waveforms characterized by ion energy or IEDF width (or IEDF shape) Making it difficult to use.

When a linear amplifier is used to bias the substrate support, the waveforms do not coincide with each cycle, and therefore, sampling at a high rate because the feature analysis of the waveform (e.g., the slope of the portion between pulses) typically does not provide useful information No need was seen. This useful information occurs when a fixed waveform is used, as can be seen in this and related publications.

The fixed waveforms and high sampling rates disclosed herein enable more accurate statistical observations. Due to this increased accuracy, the operating and processing characteristics of the plasma source and of the plasma in the chamber can be monitored through monitoring various characteristics of the modified periodic voltage function. For example, a measurement of the modified periodic voltage function enables remote monitoring of the sheath capacitance and ion current, and can be monitored without knowing the chamber process or details of other chambers. Many cases are intended to illustrate only a few of the many ways in which the above-mentioned systems and methods can be used for non-local monitoring and fault detection of sources and chambers.

Referring to Figure 14 as an example of monitoring, the DC offset of waveform 1400 may indicate the state of the plasma source (hereinafter referred to as the source). In another embodiment, the slope of the top 1404 (second portion) of the pulse of the modified period voltage function is related to the damping effect in the source. The standard deviation of the slope of the top 1404 from horizontal (shown as having a slope of zero) is another way of monitoring the source state based on the aspect of the waveform 1400. Another aspect includes measuring the standard deviation of the sampled Vo points along the fourth portion 1408 of the modified period voltage function and correlating the standard deviation to the chamber ringing. For example, if the standard deviation is monitored during successive pulses and the standard deviation increases with time, this may indicate, for example, that there is ringing in the chamber in the e-chuck. The ringing may be a signal of poor electrical connection to or in the chamber or of additional unwanted inductance or capacitance.

Figure 32 illustrates two modified period voltage functions transferred to the substrate support in accordance with one embodiment of the present disclosure. When compared, the two modified period voltage functions can be used for chamber matching or original anomaly or fault detection. For example, one of the two modified period voltage functions may be a reference waveform, and the other may be taken from the plasma processing chamber during calibration. The difference between the two modified period voltage functions (e.g., peak to peak voltage, V _PP ) can be used to calibrate the plasma processing chamber. Alternatively, the second modified periodic voltage function may be compared to the reference waveform during the processing period and the difference in waveform characteristics (e.g., shift) may cause a fault (e.g., a slope of the fourth portion 3202 of the modified periodic voltage function) ).

Figure 33 shows the ion current waveforms that can indicate changes in plasma source instability and plasma density. The fluctuation of the ion current I _I as shown in Fig. 33 can be analyzed to indicate a malfunction and an abnormality of the system. For example, the periodic variation in FIG. 33 may indicate low frequency instability in a plasma source (e.g., plasma power source 102). This variation in ion current (I _I ) also represents a periodic change in plasma density. These indicators and possible faults or anomalies that may be indicated by them are just one of many ways that the remote monitoring of the ion current I _I can be used for certain advantages.

Figure 34 shows the ion current (I _I ) of a modified periodic voltage function waveform having a non-cyclical shape. This embodiment of the ion current (I _I ) exhibits non-cyclical variations such as changes in plasma instability and plasma density. These variations may also indicate various plasma instabilities such as arc generation, formation of parasitic plasma, or drift of plasma density.

Figure 35 shows a modified period voltage function waveform that can indicate a failure within the bias supply. The top of the third illustrated cycle (also referred to as the second portion) represents an abnormal behavior that directs ringing to a bias supply (e.g., power supply 1206 in FIG. 12). This ringing may also indicate a failure inside the bias supply. Further analysis of this ringing can identify characteristics that help identify faults within the power system.

Figure 36 shows a modified period voltage function waveform that may exhibit dynamic (non-linear) variation in system capacity. For example, due to the stray capacitance that follows nonlinearly with voltage, it may appear as a result of this modified periodic voltage function. In another example, plasma collapse or failure in the chuck may also result from this modified periodic voltage function. The nonlinearity of the fourth portion 3602 of each cycle in each of the three illustrated cycles may indicate a dynamic change in system capacity. For example, non-linearity can indicate a change in sheath capacity because most of the other components of the system capacity are fixed.

Figure 37 shows a modified period voltage function that can show a change in plasma density. The illustrated modified periodic voltage function shows a monotonic shift in the slope (dVo / dt) that can indicate a change in plasma density. Such a monotonic movement can provide a simple counterpart of the expected event, such as the process etch endpoint. In another embodiment, such a monotonic shift may indicate that there is a failure in the process if no expected event is present.

Figure 38 shows the sampling of the ion current for different process runs where the drift of the ion current may indicate system drift. Each data point may represent an ion current for a given run if the acceptable acceptable limit is a user-defined or automatic limit that defines acceptable ion currents. The drift of the ion current, which gradually pushes the ion current beyond the acceptable limit, may indicate that substrate damage may occur. This type of monitoring can also be combined with any number of other conventional monitors, such as optical dropouts, thickness measurements, and the like. In addition to monitoring the drift of ionic currents, these traditional types of monitors can enhance existing monitoring and statistical control.

Figure 39 shows sampling of the ion current for different process parameters. In this embodiment, the ion current can be used as a figure of merit that distinguishes between different treatments and different treatment characteristics. Such data can be used during plasma recipe and process development. For example, by examining eleven processing conditions, eleven illustrated ion current data points have been obtained, and processing representing the desired ion current can be selected as the ideal processing, or alternatively, the preferred processing. For example, the lowest ion current can be selected as the ideal treatment, and the ion current associated with the desired treatment can then be used as a metric for determining whether the treatment has been performed according to the desired treatment conditions. Such a figure of merit may be used in addition to or in addition to similar traditional performance features such as rate, selectivity and profile angle for naming as a non-limiting example.

Figure 40 shows two modified period voltage functions monitored in a chamber without plasma. These two modified periodic voltage functions can be compared and used to characterize the plasma chamber. In an embodiment, the first modified period voltage function may be a reference waveform and the second modified period voltage function may be a current-monitored waveform. These waveforms can be taken without plasma in the process chamber after, for example, chamber cleaning or preventive checking, and thus the second waveform provides confirmation of the electrical state of the chamber prior to release of the chamber to fabricate (or return) Can be used.

Figure 41 shows two modified period voltage functions that can be used to confirm plasma processing. The first modified periodic voltage function may be a reference waveform and the second modified periodic voltage function may be the waveform being monitored. The currently monitored waveform is compared to a reference waveform, and any difference can indicate parasitic and / or non-capacitive impedance issues that can not be detected using traditional monitoring methods. For example, the ringing shown in the waveform of FIG. 35 can be detected and can mean ringing on the power supply.

Any of the measurement criteria shown in Figures 32-41 may be monitored and the method 3000 may be used to update the ion current compensation Ic, the ion current I _I , and / or the sheath capacitance C _sheath , . For example, after each ion current (I _I ) sampling is taken in FIG. 38, the method 3000 may return to sampling 3004 to determine the updated ion current I _I. Correction to the ion current (I _I ), ion energy (eV) or IEDF width as a result of the monitoring operation in other embodiments may be desired. A corresponding correction can be made and the method 300 can be repeated with sampling again to find a new ion current compensation Ic that meets equation (3).

Those skilled in the art will appreciate that the methods shown in Figures 30, 31, and 43 do not require any particular or described order of operation, nor are they limited to any order shown in the drawings or implied in the drawings I will admit that. For example, the metrics (Figures 32-41) may be monitored during or after monitoring and / or monitoring of the IEDF width and / or ion energy (eV).

Figure 44 shows various waveforms at different points in the system described herein. (Also referred to as a period voltage function), an ion current compensation (Ic 4404), a modified period voltage function 4402, a switching power supply voltage (Vps, 4406) Given the substrate voltage (Vsub, 4412), the IEDF has the width 4414 shown (which can not be scaled down) or the IEDF shape 4414. This width is wider than what is referred to as the narrow width in this disclosure. As shown, the ion current compensation (Ic, 4404) is larger than the ion current (I _I ), and the substrate voltage (Vsub, 4412) is not constant. The IEDF width 4414 is proportional to the voltage difference of the slope portion between the pulses of the substrate voltage (Vsub, 4412).

Given this non-narrow IEDF width 4414, the method starts a call to the ion current compensation (Ic) so that it is adjusted until Ic = I _I (or alternatively until it is related according to Equation 2) have. Figure 45 shows the result of a final increase change in the ion current compensation (Ic) so as to match the ion current compensation (Ic) with the ion current (I _I ). When Ic = I _I , the substrate voltage (Vsub, 4412) is substantially constant and the IEDF width 4514 progresses from narrow to narrow.

Once the narrow IEDF is achieved, the ion energy can be adjusted to a desired or defined value, as shown in FIG. Where the magnitude of the power supply voltage (alternatively the bus voltage (Vbus) of the switching mode power supply) is reduced (e.g., the maximum negative amplitude of the power supply voltage 4606 pulse is reduced). As a result, as the peak-to-peak voltage changes from V _PP1 to V _PP2 , V1 decreases to V2. The size of the substantially constant substrate voltage (Vsub, 4608) eventually decreases, thus reducing the magnitude of the ion energy from 4615 to 4614 while maintaining a narrow IEDF width.

Regardless of the adjustment of the ion energy, the IEDF width can be widened after the narrow IEDF width is achieved as shown in FIG. Where Ic = I _I (or alternatively, if Equation 2 provides a relationship between Ic and I _I ), Ic can be adjusted, and thus the slope of the portion between pulses of the modified period voltage function 4702 is also changed. As a result of the inequality of the ion current compensation (Ic) and I _I , the substrate voltage is changed from a substantially constant to a non-constant. The other result is that the IEDF width 4714 is widened from the narrow IEDF 4714 to the non-narrow IEDF 4702. The more _I Ic is adjusted away from I _I , the wider the IEDF 4714 width.

Figure 48 shows one pattern of power supply voltages that can be used to achieve one ion energy level or higher with each ion energy level having a narrow IEDF 4814 width. The magnitude of the power supply voltage 4806 varies from cycle to cycle. This result alters V and peak-to-peak voltage for each cycle of the modified period voltage function 4802. Substrate voltage 4812 has two substantially constant voltages alternating alternately between pulses of the substrate voltage. This results in two different ion energies each having a narrow IEDF 4814 width.

Figure 49 shows another pattern of power supply voltage that can be used to achieve more than one ion energy level when each ion energy level has a narrow IEDF 4914 width. Where the power supply voltage 4906 alternates between two different sizes, but for two cycles at the time before the change. As shown, the average ion energy is the same even if V _ps (4906) changes every cycle. This shows just one example of how various different patterns of V _ps (4906) can be used to achieve the same ion energy.

50 shows one combination of the power supply voltage (V _PS , 5006) and the ion current compensation (Ic, 5004) that can be used to generate the defined IEDF 5014. Here, the variation of the power supply voltage 5006 generates two different ion energies. Further, by adjusting the ion current compensation 5004 away from the ion current I _I , the width of the IEDF 5014 for each ion energy expands. If the ion energy is close enough, such as in the illustrated embodiment, the IEDF 5014 for the two ion energies overlaps to create one large IEDF 5014. Other variations are also possible, but this example implies a combination of some adjustments to V _ps (5006), where Ic 5004 can be used to achieve the defined IEDF 5014 have.

Referring now to Figures 17A and 17B, a block diagram illustrating another embodiment of the present invention is shown. As shown, the substrate support 1708 in this embodiment includes an electrostatic chuck 1782 and an electrostatic chuck supply 1780 is used to power the electrostatic chuck 1782. 17A, in some variations, the electrostatic chuck supply 1780 is positioned to apply power directly to the substrate support 1708, and in an alternative embodiment the electrostatic chuck supply 1780 is coupled to a switching mode power supply And is positioned so as to apply power. It should be noted that the serial chucking can be realized by using a control unit to realize a pure DC chucking function or by a separate supply. Such DC-coupling (for example, without any jumper capacitors) can minimize unwanted interference with other RF sources in the serial chucking function.

18 illustrates a plasma power supply 1884 that is operative to generate a plasma density and which is also configured to drive the substrate support 1808 with a switching mode power supply 1806 and an electrostatic chuck supply 1880. [ Fig. In this embodiment, each of the plasma power supply 1884, electrostatic chuck supply 1880 and switching mode power supply 1806 may be in separate assemblies or two or more supplies 1806, 1880, 1884 may be in the same physical assembly Lt; / RTI > Preferably, the embodiment shown in Fig. 18 is electrically symmetrical with the top electrode 1886 (e. G., Showerhead) electrically grounded and the damage is reduced with less arc generation.

19 is a block diagram showing another embodiment of the present invention. As shown, the switched mode power supply 1906 of this embodiment is configured to apply power to the substrate support and chamber 1904 to bias the substrate and allow the plasma power supply 1906 to operate without the aid of an additional plasma power supply (e.g., Ignites (and maintains) the plasma (without the supplies 102, 202, 1202, 1702, 1884). For example, the switched mode power supply 1806 may be operated with a duty cycle sufficient to ignite and hold the plasma while providing a bias to the substrate support.

20 is a block diagram illustrating the control parameters and input parameters that may be utilized in connection with the embodiment described with reference to Figs. 1-19. The description of the control is intended to provide a simple depiction of the exemplary control inputs and outputs, which may be used in connection with the embodiments discussed herein, and are not intended to be a hardware drawing. Controls depicted in actual implementations may be distributed among several discrete components that may be realized by hardware, software, firmware, or a combination thereof.

With respect to the embodiment discussed hereinabove, the control unit shown in FIG. 20 may provide the following functionality; One or more control units 112 are described with reference to Figure 1; The control unit 212 and the ion energy control unit 220 are described with reference to FIG. 2; The control unit 812 and the ion energy control unit 820 are described with reference to FIG. 8; The ion current compensating section 1260 is described with reference to FIG. 12; The current control section 1362 is described with reference to FIG. 13; Icc control is depicted in FIG. 16; Control units 1712A and 1712B are depicted in Figures 17A and 17B, respectively; Control units 1812 and 1912 are depicted in Figures 18 and 19, respectively.

As shown, the parameters that may be used as inputs to the control include dVo / dt and V, which are described in more detail with respect to Figures 13 and 14. [ As discussed, dVo / dt may be used in conjunction with the ion-energy-distribution-diffusion input (E) to provide the control signal Icc, which is shown in Figures 12, 13, 14, Lt; RTI ID = 0.0 > 15C < / RTI > Furthermore, the ion energy control input Ei associated with the optional feedback (V) may be used to control the ion energy control signal < RTI ID = 0.0 > (E. G., Affecting the Vbus depicted in FIG. 3). Another parameter that can be used in connection with many e-chucking embodiments is the DC offset input, which provides an electrostatic force to hold the wafer on the chuck for efficient temperature control.

21 shows a plasma processing system 2100 according to an embodiment of the present invention. The system 2100 includes a plasma processing chamber 2102 that surrounds the plasma 2104 to etch the top surface 2118 of the substrate 2106 (and other plasma processing). The plasma is generated by a plasma source 2112 (e.g., in situ, remotely or projected) that is powered by a plasma power supply 2122. The plasma sheath voltage (V _sheath ) measured between the plasma 2104 and the top surface 2118 of the substrate 2106 accelerates ions from the plasma 2104 along with the plasma sheath 2115, And collide with the top surface 2118 of the substrate 2106 to etch the substrate 2106 (or the portion of the substrate 2106 that is not protected by the photoresist). The plasma 2104 is at a plasma potential V ₃ relative to ground (e.g., the plasma processing chamber 2102 wall). The substrate 2106 has a lower surface 2120 supported electrostatically through the electrostatic chuck 2111 and a chucking potential 2180 between the upper surface 2121 of the electrostatic chuck 2111 and the substrate 2106 V _chuck ). The substrate 2106 is a dielectric and thus has a first potential V ₁ on the top surface 2118 and a second potential V ₂ on the bottom surface 2120. The upper surface of the electrostatic chuck 2121 is in contact with the lower surface 2120 of the substrate so that these two surfaces 2120 and 2121 have the same potential V ₂ . The first potential V ₁ , the chucking potential V _chuck and the second potential V ₂ are controlled through an AC waveform having an offset generated by a DC bias or a switched mode power supply 2130, 2124 to the electrostatic chuck 2111. Alternately, an AC waveform is provided through the first conductor 2124 and a DC waveform is provided through the optional second conductor 2125. The AC and DC outputs of the switched mode power supply 2130 can be controlled through the control 2132, which is also configured to control various aspects of the switched mode power supply 2130.

The ion energy and the ion energy distribution are a function of the first electric potential (V ₁ ). The switched mode power supply 2130 provides an AC waveform adapted to realize the desired first potential (V ₁ ) known to produce the desired (or defined) ion energy and ion energy distribution. The AC waveform may be RF and has a non-sinusoidal waveform such as the waveforms shown in Figs. 5, 6, 11, 14, 15A, 15B and 15C. The first potential V ₁ may be proportional to the change of the voltage V shown in Fig. The first potential V ₁ is also equal to the plasma potential V ₃ minus the plasma sheath voltage V _sheath . However, the plasma potential (V ₃₎ is often plasma sheath voltage (V _sheath) (e. G., 50V-2000V) is small compared to the due (e.g., less than 20V) the first potential (V ₁₎ and the plasma sheath voltage (V _sheath ) are approximately the same and can be treated the same for the _{sake of} implementation. Therefore, since the plasma sheath voltage (V _sheath ) depends on the ion energy, the first electric potential (V ₁ ) is proportional to the ion energy distribution. By maintaining a constant first potential (V ₁ ), the plasma sheath voltage (V _sheath ) becomes constant, so that substantially all of the ions are accelerated through the same energy, thus achieving a narrow ion energy distribution. The plasma voltage V ₃ is obtained from the energy transferred to the plasma 2104 through the plasma source 2112.

The first electric potential V ₁ of the upper surface 2118 of the substrate 2106 is formed through a combination of capacitive charging from the electrostatic chuck 2111 and charge formation from electrons and ions passing through the sheath 2115. The AC waveform from the switching mode power supply 2130 is made to cancel out the effects of the transfer of ions and electrons through the sheath 2115 and the resulting charge buildup on the top surface 2118 of the substrate 2106, V ₁ ) remains substantially constant.

The chucking force for holding the substrate 2106 on the electrostatic chuck 2111 is a function of the chucking potential (V _chuck ). The switching mode power supply 2130 provides a DC bias or a DC offset to the AC waveform so that the second potential V ₂ has a potential different from the first potential V ₁ . This potential difference causes a chucking voltage (V _chuck ). A chucking voltage V _chuck may be established from the top surface 2221 of the electrostatic chuck 2111 to the reference layer inside the substrate 2106 to exclude the reference layer from the bottom surface 2120 of the substrate 2106 (The exact position inside the substrate 2106 of the reference layer may vary). Accordingly, the chucking is controlled by a second potential (V ₂₎ being proportional to the second voltage (V _2).

In an embodiment, the second potential V ₂ is equal to the DC offset of the switched mode power supply 2130, which is modified by the AC waveform (in other words, if the DC offset is greater than the peak to peak voltage of the AC waveform, AC waveform). The DC offset is substantially greater than the AC waveform, so that the DC component of the output of the switched mode power supply 2130 dominates the second potential (V ₂ ) and the AC component can be neglected or left unattended.

The potential inside the substrate 2106 changes between the first and second potentials V ₁ and V ₂ . Substrate (coulombic attractive force) the Coulomb attraction between 2106 and chuck 2111 is chucked potential (V _chuck) due to the presence, regardless of the chucking voltage (V _chuck) is positive or negative (for example, V ₁ > V ₂ or V ₁ <V ₂ ).

The switching mode power supply 2130 along with the control unit 2132 can deterministically monitor various voltages without sensors. In particular, the ion energy (e.g., average energy and ion energy distribution) can be deterministically monitored based on the parameters of the AC waveform (e.g., slope and step). For example, the plasma voltage (V ₃ ), ion energy, and ion energy distribution are proportional to the parameters of the AC waveform produced by the switching mode power supply 2130. In particular, V of the falling edge of the AC waveform (see FIG. 14) is proportional to the first potential V ₁ and hence to the ion energy. The ion potential distribution can be kept narrow by keeping the first electric potential V ₁ constant.

Although the first potential V ₁ can not be directly measured and the correlation between the switching mode power supply output and the first voltage V ₁ varies based on the capacity and processing parameters of the substrate 216, The proportional constant between the first electric potentials V ₁ can be determined empirically after a short time has elapsed. For example, the falling edge (V) of the AC waveform is 50V, the case that the proportional constant is 2 for a given substrate and a process of empirically found by a first potential (V ₁₎ may be expected to be a 100V. The proportion between the step voltage V and the first electric potential V ₁ (and hence the ion energy eV) is explained by the equation (4). Thus, the first potential (V ₁ ) along with the ion energy and the ion energy distribution can be determined based on the recognition of the AC waveform of the switched mode power supply without any sensor inside the plasma processing chamber 2102. Furthermore, the switched mode power supply 2130 monitors when and when chucking is performed (e.g., whether the substrate 2106 is held on the electrostatic chuck 2111 via a chucking potential (V _chuck )) .

The chucking is performed by removing or reducing the chucking potential (V _chuck ). This can be performed by set equal to the second potential (V ₂₎ and the first potential (V _1). In other words, the DC offset and the AC waveform can be adjusted so that the chucking voltage (V _chuck ) approaches 0V. The system 2100 can achieve faster de-chucking and hence higher throughput because the DC offset and AC waveform can be adjusted to achieve chucking as compared to conventional chucking methods. In addition, when DC and AC power supplies are provided in the switched mode power supply 2130, the circuitry can be more integrated, closer, and controlled through a single control 2132 (DC and AC power supplies are typically parallel Layout), the output changes more quickly. The chucking rate enabled by the embodiments disclosed herein also enables chucking after the plasma 2104 has evolved or at least after the power is turned off from the plasma source 2112. [

The plasma source 2112 may have various forms. For example, in an embodiment, the plasma source 2112 includes an electrode inside a plasma processing chamber 2102 that forms an RF field within a chamber 2102 that ignites and holds the plasma 2104. In another embodiment, the plasma source 2112 includes a remote projection plasma source that remotely generates and projects an ionizing electromagnetic field or extends the ionizing electromagnetic field to the processing chamber 2102, The plasma 2104 is ignited and held. In addition, the remotely-projected plasma source can be used to determine whether the field strength in the plasma processing chamber 2102 is only 1/10, 1/100, or 1/1000 or a much smaller portion of the field intensity (E.g., a conductive tube) through which the ionizing electromagnetic field passes to the plasma processing chamber 2102 for a period of time during which the ionizing electromagnetic field is attenuated. The plasma source 2112 is not drawn to scale.

The switched mode power supply 2130 may be floated and thus biased by any DC offset by a DC power source (not shown) connected in series between ground and the switched mode power supply 2130. The switching mode power supply 2130 may be coupled to an AC and DC power source (e.g., Figure 22, Figure 23, Figure 26) within the switching mode power supply 2130, (E.g., see FIGS. 24 and 27) to provide an AC waveform having a DC offset through the DC power supply external to the AC power source and the switched mode power supply 2130. In an embodiment, the switched mode power supply 2130 may be grounded and coupled in series with a floating DC power source coupled in series between the switched mode power supply 2130 and the electrostatic chuck 2111.

The control unit 2132 can control the AC and DC outputs of the switched mode power supply 2130 when the switched mode power supply 2130 includes both AC and DC power sources. When the switching mode power supply 2130 is connected in series with the DC power source, the control unit 2132 can only control the AC output of the switching mode power supply 2130. [ In an alternative embodiment, the controller 2130 can control both the DC power supply connected to the switched mode power supply 2130 and the switched mode power supply 2130. Those skilled in the art will recognize that although a single control 2132 is shown, other controls may also be implemented to control the DC offset and AC waveform provided to the electrostatic chuck 2111. [

The electrostatic chuck 2111 may be a dielectric, thus substantially blocking the passage of the DC voltage, and may also consist of a semiconductor material such as doped ceramic. In either case, the electrostatic chuck 2111 has a top surface 2121 of the electrostatic chuck 2111 capacitively coupled to the top surface 2118 of the substrate 2106 (usually a dielectric) to form a first voltage V ₁ , in may have a second voltage (V _2).

The shape and size of the plasma 2104 are not necessarily drawn to scale. For example, the edge of the plasma 2104 may be defined by any plasma density at which the illustrated plasma 2104 is not drawn with any particular plasma density in mind. Similarly, at least some plasma densities fill the entire plasma processing chamber 2102 despite the shape of the plasma 2104 shown. The shape of the illustrated plasma 2104 is intended to preferentially show the sheath 2115 and the sheath 2115 has a plasma density that is substantially less than that of the plasma 2104.

FIG. 22 shows another embodiment of the plasma processing system 2200. In the illustrated embodiment, the switched mode power supply 2230 includes a series connected DC power source 2234 and an AC power source 2236. The control unit 2232 is configured to control the AC waveform with the DC offset output of the switched mode power supply 2230 by controlling both the AC power source 2236 waveform and the DC power source 2234 bias or offset. This embodiment also includes an electrostatic chuck 2211 having a grid or mesh electrode 2210 embedded in the chuck 2211. [ The switching mode power supply 2230 provides AC and DC bias to the grid electrode 2210. The DC bias together with the AC component, which is substantially smaller than the DC bias and thus can be ignored, forms the third potential V ₄ on the grid electrode 2210. When the third potential V ₄ is different from the potential at any reference layer inside the substrate 2206 (except for the lower surface 2220 of the substrate 2206), the chucking potential V _chuck and the coulomb chucking force Is formed so as to hold the substrate 2206 on the electrostatic chuck 2211. The reference layer is a virtual surface parallel to the grid electrode 2210. The AC waveform is capacitively coupled from the grid electrode 2210 through a portion of the electrostatic chuck 2211 and is applied to the top surface 2218 of the substrate 2206 through the substrate 2206 at a first potential V ₁ . Since the plasma potential V ₃ is relatively negligible with respect to the plasma sheath voltage V _sheath , the first potential V ₁ and the plasma sheath voltage V _sheath are considered to be substantially the same and substantially the same. Thus, the first potential V ₁ is equal to the potential used to accelerate the ions through the sheath 2215.

The electrostatic chuck 2211 can be doped to be sufficiently conductive so that any potential difference can be neglected through the body of the chuck 2211 so that the grid or mesh electrode 2210 is at the second potential (V < ₂ >).

The grid electrode 2210 may be any conductive planar device arranged parallel to the substrate 2206 and embedded in the electrostatic chuck 2211 and may be biased by the switching mode power supply 2230 to provide a chucking potential V _chuck . &Lt; / RTI > Although grid electrode 2210 is shown embedded in the lower portion of electrostatic chuck 2211, grid electrode 2210 may be closer to substrate 2206 or further away from the substrate. The grid electrode 2210 also need not have a grid pattern. In an embodiment, the grid electrode 2210 may be a solid electrode or a non-solid structure (checkerboard pattern) having a non-grid shape. The electrostatic chuck 2211 is a ceramic or other dielectric material so that the third potential V ₄ of the grid electrode 2210 is higher than the first potential V ₁ of the upper surface 2221 of the electrostatic chuck 2211 It is not the same. The third potential V ₄ with respect to the grid electrode 2210 is applied to the upper surface 2221 of the electrostatic chuck 2211 by the electrostatic chuck 2211. In other embodiments, the electrostatic chuck 2211 is made of a slightly conductive doped ceramic, 2 may be the same as the electric potential (V _2).

The switched mode power supply 2230 generates an AC output that can be non-sinusoidal. The switched mode power supply 2230 can operate in series with the DC and AC sources 2234 and 2236 because the DC power source 2234 is AC-conductive and the AC power source 2236 is DC-conductive. An exemplary non-DC AC power source is any linear amplifier that can be damaged when a DC voltage or current is applied. The use of AC-conductive and DC-conductive power sources reduces the number of components used in the switched mode power supply 2230. For example, if the DC power source 2234 is AC-interrupted, then the AC-bypass or DC-intercepted component (e.g., a capacitor) should be arranged in parallel with the DC power source 2234. If the AC power source 2236 is DC-cutoff, the DC-bypass or AC-cutoff component (e.g., an inductor) must be arranged in parallel with the AC power source 2236.

In this embodiment, the AC power source 2238 is entirely configured to apply a voltage bias to the electrostatic chuck 2211 in a controllable manner, so that the desired level of ions impinging on the top surface 2218 of the substrate 2206 (Defined) ion energy distribution. More specifically, the AC power source 2236 is configured to achieve a desired (or defined) ion energy distribution by applying one or more specific waveforms to the grid electrode 2210 at a specific power level. More specifically, the AC power source 2236 applies a particular power level to achieve a particular ion energy and applies a particular power level using one or more voltage waveforms defined by the waveform data stored in the waveform memory (not shown) do. As a result, one or more specific ion impact energy can be selected to realize controlled etching (or other plasma-assisted processing) of the substrate 2206. In one embodiment, the AC power source 2236 may use a switching mode configuration (e.g., see Figures 25-27). The switching mode power supply 2230 and in particular the AC power source 2236 may produce an AC waveform as described in the various embodiments of this disclosure.

Those skilled in the art will appreciate that the grid electrode 2210 is not essential and that other embodiments may be implemented without the grid electrode 2210. Those of ordinary skill in the art will also recognize that grid electrode 2110 is only one example of a number of devices that may be used to form a chucking potential (V _chuck) .

23 shows another embodiment of the plasma processing system 2300. [ The illustrated embodiment includes a switching mode power supply 2330 for providing an AC waveform and a DC bias to the electrostatic chuck 2311. The switched mode power supply 2330 includes a DC power source 2334 and an AC power source 2336, which can each be grounded. The AC power source 2336 generates an AC waveform that is provided to the first grid or mesh electrode 2310 buried in the electrostatic chuck 2311 via the first conductor 2324. An AC power source 2336 forms a potential (V ₄ ) at the first grid or mesh electrode 2310.

The DC power source 2334 generates a DC bias that is provided to the second grid or mesh electrode 2312 buried in the electrostatic chuck 2311 via the second conductor 2325. The DC power source 2334 forms a potential V ₅ at the second grid or mesh electrode 2312. The potentials V ₄ and V ₅ can be independently controlled through the AC and DC power sources 2336 and 2343, respectively. However, the first and second grid or mesh electrodes 2310, 2312 can also be capacitively coupled and the DC coupling between the grid or mesh electrodes 2310, 2312 through a portion of the electrostatic chuck 2311 Lt; / RTI > If AC or DC coupling is present, then the potentials (V ₄ , V ₅ ) can be combined. Those skilled in the art will understand that the first and second grid electrodes 2310 and 2312, including arranging the first grid electrode 2310 closer to the substrate 2306 than the second grid electrode 2312, Can be arranged at various positions through the electrostatic chuck 2311. [

24 shows another embodiment of a plasma processing system 2400. [ In this embodiment, the switched mode power supply 2430 provides an AC waveform to the electrostatic chuck 2411 and the output of the switched mode power supply 2430 is offset by the DC bias provided by the DC power supply 2434 . The AC waveform of the switching mode power supply 2430 has a waveform selected by the control unit 2435 such that ions impinge on the substrate 2406 from the plasma 2404 having a narrow ion energy distribution. The AC waveform may be a non-sinusoidal file (e.g., a square wave or a pulsed wave) and may be generated via an AC power source 2436 of a switched mode power supply 2430. Chucking is controlled via a DC offset from a DC power supply 2434 controlled by the control unit 2433. The DC power supply 2434 may be coupled in series between ground and the switched mode power supply 2430. The switching mode power supply 2430 is in a floating state so that the DC bias can be set by the DC power supply 2434.

Those skilled in the art will recognize that the illustrated embodiment shows two independent controls 2433 and 2435, but may be combined into a single functional unit, device, or system, such as optional control 2432 something to do. Furthermore, the controllers 2433 and 2435 can be coupled to each other and to communicate with the distributed processing resources.

Fig. 25 shows another embodiment of the plasma processing system 2500. Fig. The illustrated embodiment includes a switched mode power supply 2530 that generates an AC waveform having a DC offset provided by a DC power supply (not shown). The switching mode power supply may be controlled via an optional control 2535 including voltage and current controls 2537 and 2539. The switching mode power supply 2530 includes a controllable voltage source 2538 having a voltage output controlled by a voltage control 2537 and a controllable current source 2540 having a current output controlled by a current control 2539 . The controllable voltage and current sources 2538 and 2540 may be arranged in parallel. A controllable current source 2540 is configured to compensate for the ion current between the plasma 2504 and the substrate 2506.

The voltage and current controllers 2537 and 2539 can be coupled and communicated with each other. The voltage control unit 2537 can also control the switching output 2539 of the controllable voltage source 2538. The switching output 2539 includes two switches in parallel as shown and includes any circuitry that converts the output of the voltage source 2538, which can be controlled by a desired AC waveform (e.g., non-sinusoidal) can do. A voltage or AC waveform controlled from a voltage source 2538, which is controllable via two switches, can be combined with the controlled current output of the controllable current source 2540 to generate an AC waveform output of the switched mode power supply 2530 .

Although the controllable voltage source 2538 is shown as having a given polarity, those of ordinary skill in the art will recognize that the opposite polarity is equivalent to that shown. The controllable voltage and current sources 2538 and 2540 along with the selectively selected output 2539 may be part of the AC power source 2536 and the AC power source 2536 may be coupled to the power supply 2530, And may be arranged in series with a DC power source (not shown).

Fig. 26 shows another embodiment of a plasma processing system 2600. Fig. In the illustrated embodiment, the switching mode power supply 2630 provides an AC waveform with a DC offset to the electrostatic chuck 2611. The AC components of the waveform are generated through a parallel combination of a controllable voltage source 2638 and a controllable current source 2640 that are connected to each other through a switching output 2639. [ The DC offset is generated by a DC power source 2634 coupled in series between ground and a controllable voltage source 2638. In an embodiment, the DC power source 2634 may be floated above ground. Similarly, the switched mode power supply 2630 may be floating or grounded.

System 2600 includes one or more controls for controlling the output of switching mode power supply 2630. The first controller 2632 may control the output of the switching mode power supply 2630, for example, through the second and third controllers 2633 and 2635. The second control unit 2633 can control the DC offset of the switching mode power supply 2630 generated by the DC power source 2634. [ The third control unit 2635 can control the AC waveform of the switching mode power supply 2630 by controlling the controllable voltage source 2638 and the controllable current source 2640. [ In the embodiment, the voltage control unit 2637 controls the voltage output of the controllable voltage source 2638, and the current control unit 2639 controls the current of the controllable current source 2640. The voltage and current control units 2637 and 2639 can communicate with each other and can be a part of the third control unit 2635.

Those skilled in the art will appreciate that the above embodiments that illustrate the various configurations of the controls associated with power sources 2634, 2638, 2640 are not limited, and that various other configurations may be implemented without departing from this disclosure Will recognize. For example, the third control unit 2635 and the voltage control unit 2637 can control the switching output 2639 between the controllable voltage source 2638 and the controllable current source 2640. As another embodiment, the second and third controllers 2633 and 2635 can communicate with each other (although not shown as such). It should also be appreciated that the polarity of the controllable voltage and current sources 2638, 2640 is merely exemplary and not meant to be limiting.

The switching output 2639 operates by alternately switching the two parallel switches to shape the AC waveform. The switching output 2639 may include various switches including MOSFETs and BJTs without limitation. In one variation, a DC power source 2634 may be arranged between the controllable current source 2640 and the electrostatic chuck 2611 (in other words, the DC power source 2634 may be floating), a switching mode power supply (2630) may be grounded.

FIG. 27 shows another embodiment of a plasma processing system 2700. FIG. In this variation, the switched mode power supply 2734 is again grounded, but instead of being integrated with the switched mode power supply 2630, the DC power source 2734 is comprised of discrete components, And provides a DC offset to the entire switching mode power supply 2630 instead of the obvious internal components.

28 shows a method 2800 according to an embodiment of the present invention. The method 2800 includes positioning the substrate in a plasma chamber operation 2802. The method 2800 also includes forming a plasma in a plasma chamber operation 2804. Such a plasma may be formed through in situ or remote protrusion sources. The method 2800 includes a switching power operation 2806. Switching power operation 2806 includes controllably switching the power to the substrate to apply a periodic voltage function to the substrate. The periodic voltage function may be a pulsed waveform (e.g., a square wave) or an AC waveform, and includes a DC offset generated by a DC power source in series with a switched mode power supply. In an embodiment, the DC power source may be integrated with a switched mode power supply and thus configured in series with an AC power source of the switched mode power supply. The DC offset generates a potential difference between the top surface of the electrostatic chuck and the reference layer inside the substrate, and this potential difference is called the chucking potential. The chucking potential between the electrostatic chuck and the substrate holds the substrate in the electrostatic chuck thereby preventing the substrate from moving during processing. The method 2800 also includes a modulation operation 2808 in which the periodic voltage function is modulated over multiple cycles. The modulation responds to the desired (defined) ion energy distribution on the surface of the substrate to achieve the desired (defined) ion energy distribution on a time-averaged basis.

29 shows another method according to an embodiment of the present invention. The method 2900 includes positioning the substrate in a plasma chamber operation 2902. The method 2900 also includes forming a plasma in a plasma chamber operation 2904. Such a plasma may be formed through in situ or remote protrusion sources. The method 2900 also includes receiving at least one ion energy distribution setting operation 2906. The settings received in the receive operation 2906 may indicate one or more ion energies on the surface of the substrate. The method 2900 also includes a switching power operation 2908 in which the power to the substrate is controllably switched to achieve the following: (1) a desired (defined) Ion energy distribution; And the desired chucking potential in a time-averaged manner. Power can have AC waveform and DC offset.

In conclusion, the present invention can provide a method and apparatus among others for selectively generating the desired (or defined) ion energy using a switched mode power supply. Those skilled in the art will readily recognize that many variations and substitutions can be made in the configuration that achieves substantially the same results as achieved by the invention, its use, and the embodiments described herein. Accordingly, there is no intention to limit the invention to the exemplified forms disclosed. Many variations, modifications and alternative arrangements are within the scope and spirit of the disclosed invention.

Claims

An apparatus for providing a modified periodic voltage function to an electrical node configured to be coupled to a substrate support of a plasma processing chamber,
Providing a periodic voltage function to the electrical node, the periodic voltage function comprising: a power supply having a pulse and a portion between the pulses;
An ion current compensation unit for correcting a slope of a portion between pulses to provide ion current compensation to form a modified period voltage function; And
The control unit, in communication with the switching mode power supply (SMPS) and the ion current compensation element, is configured to identify a value of the ion current compensation, which is represented by a defined ion energy distribution function of ions reaching the substrate surface when supplied to the electrical node / RTI >

2. The apparatus of claim 1, wherein the power supply is a switched mode power supply.

3. The apparatus of claim 2, wherein the switching mode power supply comprises one or more switching elements.

The apparatus of claim 1, wherein the control unit samples two or more voltages from a modified period voltage function and calculates a slope (dVo / dt) of at least two voltages.

5. The apparatus of claim 4, wherein the slope (dVo / dt) is calculated based on at least two voltages sampled from a portion of the modified period voltage function between pulses of the modified period voltage function.

6. The apparatus of claim 5, wherein the controller is configured to initially adjust a switching mode power supply voltage to form an average ion energy of a first set of ions reaching a surface of the substrate.

7. The apparatus of claim 6, wherein the controller is configured to adjust a second switching mode power supply voltage to form an average ion energy of a second set of ions reaching the surface of the substrate.

6. The apparatus of claim 5, wherein the switched mode power supply is configured to adjust a voltage step of a modified periodic voltage function to form an average ion energy of a first set of ions reaching the surface of the substrate.

6. The apparatus of claim 5, wherein the switching mode power supply is configured to adjust a peak-to-peak voltage of a modified period voltage function to form an average ion energy of a first set of ions reaching the surface of the substrate.

6. The apparatus of claim 5, wherein the switching of the at least one switching element affects the slope for a portion of the modified periodic voltage function between the pulses of the modified periodic voltage function.

2. The apparatus of claim 1, wherein the controller adjusts the amplitude of the ion current compensation until a defined ion energy distribution function of the ions reaching the surface of the substrate is achieved.

1. A method for providing a modified periodic voltage function to an electrical node configured to be electrically coupled to a substrate support of a plasma processing chamber,
Providing an ion current compensation (Ic) to the electrical node;
Providing a modified period voltage function by an ion current compensation (Ic) to form a modified period voltage function at the electrical node;
Providing a pulse at the electrical node and a modified period voltage function having a portion between the pulses;
Accessing an effective capacitance value (C1) indicative of a minimum capacitance of the substrate support;
Determining a slope (dVo / dt) of a portion between pulses of the modified periodic voltage function; And
Identifying a value of an ion current compensation (I _C ) that is a defined ion energy distribution function of ions reaching the surface of the substrate, wherein the identification is based on a slope (dV ₀ / dt ) And the effective capacitance (C ₁ ).

13. The method of claim 12, wherein the defined ion energy distribution is a narrow ion energy distribution.

13. The method of claim 12, wherein the value of the ion current compensation (I _C ), which is a defined ion energy distribution function of the ions reaching the surface of the substrate, is a value that satisfies the function (f)

15. The method of claim 14,
Setting the ion current compensation (I _C ) to a first value;
Determining a sign of the function (f); And
Increasing the ion current compensation (I _C ) if the sign of the function (f) is positive and decreasing the ion current compensation (I _C ) if the sign of the function (f) is negative.

13. The method of claim 12, wherein said identifying comprises sampling the voltage of a portion between pulses of the modified period voltage function more than twice.

17. The method of claim 16, wherein said identification comprises the step of calculating a slope (dV ₀ / dt) from the voltage sampled at least two times.

18. The method of claim 17, wherein said identifying comprises: determining a slope (dV ₀ / dt) for two or more cycles of the modified periodic voltage function when each of the two or more cycles is associated with another value of the ion current compensation (I _C ) &Lt; / RTI >

The method of claim 16, wherein the gradient steps of the identification from a first cycle and a second step, at least the two sampled voltages to sample the portion of voltage between the changed cycle of the voltage function pulse during the second cycle (dV ₀ / dt). < / RTI >

13. The method of claim 12, wherein the ion current compensation (I _C ) is linearly related to an ion current (I _I ) along a plasma sheath of a plasma formed in a plasma processing chamber.

13. The method according to claim 12, wherein the ion current compensation (I _C ) is linearly related to an ion current (I _I ) according to the following equation.

Where C ₁ is the effective capacity of the plasma chamber and C _stray is the accumulated stagnation capacity of the plasma chamber.

22. The method of claim 21, wherein the effective capacitance (C ₁ ) varies with time.

22. The method of claim 21, wherein the ion current compensation (I _C ) changes over time.

13. The method of claim 12,
Providing the modified periodic voltage function to the electrical node such that ions reach the surface of the substrate with the first ion energy.

25. The method of claim 24, wherein the modified periodic voltage function has a first voltage step corresponding to the first ion energy.

25. The method of claim 24,
And providing the electrical node with the modified periodic voltage function having an ion current compensation (I _C ) of a second value to extend the ion energy distribution function.

26. The method of claim 25, wherein the first voltage step and the second voltage step are provided in adjacent cycles of the modified period voltage function.

25. The method of claim 24, wherein the providing step has a negligible effect on the density of the plasma.

Applying a modified periodic voltage function constituting a modified period voltage function by ion current compensation to an electrical node configured to be coupled to a substrate support coupled to a substrate in a plasma processing chamber;
Sampling at least one cycle of the modified period voltage function to generate a voltage data point;
Estimating a first ion energy value for ions reaching the surface of the substrate based on the voltage data point; And
Adjusting the modified periodic voltage function until the first ion energy becomes equal to the defined ion energy.

30. The method of claim 29,
Sampling at least one cycle of the modified periodic voltage function, and estimating a value of the first ion energy after adjusting each voltage increment.

30. The method of claim 29, wherein the estimate is a function of an ion current.

32. The method of claim 31 wherein the ion current is a function of ion current compensation.

33. The method of claim 32, wherein the following equation is used to estimate the value of the first ion energy.

Where V is the voltage step of each cycle of the modified periodic voltage function, C ₁ is the effective capacitance of the chamber, and C _sheath is the sheath capacitance of the plasma sheath affected by the ion current.

34. The method of claim 33,
Wherein the adjusting includes adjusting a step voltage (DELTA V) of the modified period voltage function until the first ion energy becomes equal to the defined ion energy.

30. The method of claim 29,
Further comprising changing a first value of the ion current compensation (I _C ) to a second value to extend the width of the distribution of ion energy.

30. The method of claim 29, wherein the adjusting comprises adjusting the bias supply voltage until the first ion energy is equal to the defined ion energy.

Providing a modified period voltage function to an electrical node configured to be coupled to a substrate support of a plasma processing chamber;
Sampling at least two voltages from the modified period voltage function at a first time and a second time;
Calculating a slope of at least two voltages as dV / dt;
Comparing the slope to a known reference slope to correspond to an ion energy distribution function width; And
And adjusting the modified periodic voltage function such that the slope reaches a reference slope.

38. The method of claim 37, wherein the first time occurs during a first cycle of the modified period voltage function and the second time occurs during a second cycle of the modified period voltage function.

38. The method of claim 37, wherein the first time and the second time occur during the same cycle of the modified period voltage function.

38. The method of claim 37, wherein the sampling is performed at a sampling rate of at least 400 kHz.

A non-transitory type computer readable recording medium encoded with instructions readable by a processor to perform a method of identifying a defined ion current compensation (Ic)
Sampling the modified period voltage function when the ion current compensation (Ic) having the first value is made;
Sampling the modified period voltage function when an ion current compensation (Ic) having a second value is made;
Accessing a effective capacity (C ₁ ) for a plasma processing chamber;
Determining a slope (dVo / dt) of the modified period voltage function based on the first and second sampling; And
Equation:

And computing a third value of the ion current compensation (Ic) that causes the current to be true. &Lt; Desc / Clms Page number 24 >

42. The method of claim 41,
Further comprising calculating a cis voltage across the plasma sheath of the plasma of the plasma processing chamber.