Waveform shape factor of pulsed pvd power

Abstract

A power supply, a waveform function generator, and a method for controlling a plasma process are described. The power supply or waveform function generator includes components for performing the method in which a waveform shape variation index is determined during the plasma process and whether the waveform shape variation index meets a predetermined tolerance is evaluated.

Description

Technical Field

[0001] The embodiments of this disclosure are generally related to physical vapor deposition (PVD) chambers and methods. More specifically, the embodiments of this disclosure relate to PVD chambers and deposition methods using pulsed PVD with a controller power waveform. Background Technology

[0002] Current physical vapor deposition (PVD) processing chambers are prone to reduced uniformity and repeatability with variations in power regulation. Power regulation is typically used to drive pulsed PVD plasma chambers with voltage / current waveforms of specific shapes. These voltage / current waveforms are designed to achieve certain film characteristics or properties.

[0003] The same average power, voltage, or current can be transmitted within pulses with different waveform shapes, such as... Figure 1 As shown, different waveform shapes correspond to different plasma characteristics in the PVD chamber. Due to chamber load conditions, plasma instability, chamber plasma arc discharge, or load variations, and sometimes due to power supply failures and power transmission output cable hardware faults, the power / voltage / current waveform shapes drift or change drastically. These waveform shape variations affect the thin film properties due to changes in chamber plasma conditions.

[0004] Therefore, if the power / voltage / current waveform changes, it is necessary to detect / add / ensure the performance of the pulsed PVD chamber deposited film. Summary of the Invention

[0005] One or more embodiments of this disclosure relate to methods for controlling plasma processing. These methods include determining a waveform shape change index during deposition processing; determining whether the waveform shape index is within a predetermined tolerance; and determining subsequent actions of the plasma processing.

[0006] Additional embodiments of this disclosure relate to methods for matching plasma processing with a reference plasma processing. These methods include determining a waveform shape factor during plasma processing. Using the waveform shape factor and the average reference waveform shape factor from the reference plasma processing To determine the waveform shape change index I S Based on the waveform shape index I S Determine whether the plasma treatment matches the reference plasma treatment.

[0007] A further embodiment of this disclosure relates to a power supply including a self-diagnostic function that indicates a fault. The self-diagnostic function includes a controller configured to determine a waveform shape factor. Or waveform shape change index I S One or more of them. Attached Figure Description

[0008] To gain a more detailed understanding of the features described above in this disclosure, a more specific description of the disclosure, which has been briefly outlined above, can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only typical embodiments of this disclosure and should not be considered as limiting the scope of this disclosure, as other equally effective embodiments are permissible.

[0009] Figure 1 The diagram illustrates waveform shapes according to one or more embodiments of this disclosure;

[0010] Figures 2A to 2D The diagram illustrates waveform shapes according to one or more embodiments of this disclosure;

[0011] Figure 3 The illustrations depict methods according to one or more embodiments of this disclosure;

[0012] Figure 4 The illustrations depict methods according to one or more embodiments of this disclosure; and

[0013] Figure 5 The illustration shows a power supply according to one or more embodiments of the present disclosure. Detailed Implementation

[0014] Before describing the various exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the details of the construction or processing steps set forth in the following description. This disclosure can have other embodiments and can be practiced or carried out in various ways.

[0015] As used in this specification and the appended claims, the term "substrate" refers to a surface or a portion thereof on which a treatment is performed. Those skilled in the art will also understand that, unless the context clearly indicates otherwise, reference to substrate may also refer only to a portion of the substrate. Furthermore, reference to deposition on a substrate may mean both a bare substrate and a substrate on which one or more films or features are deposited or formed.

[0016] As used herein, “substrate” means any substrate on which a film treatment is performed during the manufacturing process, or a material surface formed on a substrate. For example, depending on the application, substrate surfaces on which treatments can be performed include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. Substrates can be exposed to pretreatment processes such as polishing, etching, reduction, oxidation, hydroxylation, annealing, UV curing, electron beam curing, and / or baking of the substrate surface. In addition to performing film treatments directly on the surface of the substrate itself, any of the disclosed film treatment steps may also be performed on an underlayer formed on the substrate, as disclosed in more detail below, and the term “substrate surface” is intended to include such an underlayer as the context suggests. Thus, for example, when a film / layer or a portion of a film / layer has already been deposited onto the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0017] One or more embodiments of this disclosure provide apparatus and / or methods for quantifying waveform distortion / variation relative to a predetermined or preset waveform shape during chamber operation. In some embodiments, the predetermined or preset waveform shape provides known plasma properties for a membrane with specific characteristics. In some embodiments, the preset or predetermined waveform is stored in the PVD chamber configuration as a best known method (BKM).

[0018] In some implementations, the waveform shape factor is calculated based on measurements from internal hardware and / or firmware of the power supply. In other implementations, the transmitted voltage and / or current are sampled externally, and the waveform shape factor is calculated in real time by an external computer that acquires data / communications from the sensors.

[0019] In some implementations, waveform factors are used to measure the performance of the processing chamber over time. In some implementations, the waveform factor measured in real time is compared with a stored BKM waveform factor to evaluate PVD chamber performance. The real-time waveform factor comparison in some implementations indicates whether the system has drifted or changed, or may be experiencing chamber mismatch problems that could affect chamber performance. In some implementations, the waveform factor of the processing chamber is compared with the waveform factor of a stored reference or "gold" chamber to allow for chamber mismatch.

[0020] refer to Figure 1Examples of rectangular voltage waveforms (thick solid lines) and triangular waveforms (dashed lines) are provided. During the pulse, the mean voltage / average voltage from both waveforms is the same, as shown in equations (I) and (II). The overall shape of the pulse differs, with the maximum voltage (V) of the falling triangular pulse being different. 峰值 The voltage is twice that of a rectangular waveform. Although the examples below discuss voltage values ​​for the waveforms, those skilled in the art will recognize that these values ​​can indicate waveform power or current.

[0021] Rectangular shape:

[0022] Descending triangle shape:

[0023] Figure 2A , Figure 2B and Figure 2D Other waveform shapes are illustrated. Figure 2C The diagram shows... Figure 1 The descending triangle shown is for comparison purposes. Figure 2A In the context of V0, when the shaded area of ​​the "W"-shaped region below V0 is equal to the shaded area above V0, the average value equals V0. Figure 2B In the triangle, when the peak value of the triangle is twice the value of V0, the average value is equal to V0. Figure 2C The diagram illustrates the relationship between... Figure 1 A descending triangle of the same shape, where the peak is twice V0 and the mean is equal to V0. Figure 2D The diagram illustrates the relationship between... Figure 2C The opposite is a descending triangle shape, where the peak is twice V0 and the average is equal to V0. Figures 2A to 2D Each of the different waveforms shown has the same average value (V). 平均 The average value is equal to V0 of the rectangular signal. However, each waveform shape is different.

[0024] To evaluate the differences between waveforms with the same average voltage, equation (III) can be used to determine the waveform shape factor (S), and equation (IV) can be used to determine the average waveform shape factor (S). avg or ).

[0025]

[0026] Where v(t) is the measured real-time voltage; and v 平均 It is a moving average obtained through real-time measurement, or a given value predetermined by software, firmware, or the user.

[0027]

[0028] Applying equations (III) and (IV), Figure 1 The theoretical average waveform shape factor of the rectangular waveform pattern shown The value is 0. However, those skilled in the art will recognize that the average waveform factor may deviate from the theoretical value due to variations in actual measurements and data processing. For example, variations in the signal-to-noise ratio (SNR) may affect the actual calculation of the average waveform factor.

[0029] Figure 2C and Figure 2D Although the illustrated embodiments appear as mirror images of each other, they have different average waveform factors. Figure 2C and Figure 2D The average waveform factors are 76 / 3 and 1 / 3, respectively. Those skilled in the art will recognize that the average waveform factor represents different waveforms.

[0030] Figure 3 Method 100 according to one or more embodiments of this disclosure is illustrated. Method 100 in some embodiments can be used to evaluate performance drift in a plasma processing chamber due to changes in plasma impedance caused by arc discharge and / or plasma instability. The methods described herein generally refer to this process as physical vapor deposition or PVD processing. However, those skilled in the art will recognize that these methods are applicable to any plasma processing, and this disclosure is not limited to physical vapor deposition processing. In some embodiments, the method is used to address other common waveform shapes, including other forms of triangular shapes, sinusoidal shapes, or envelope (modulation) shapes containing multiple dominant frequencies and amplitudes (not illustrated herein). Some embodiments of this disclosure are used for semiconductor PVD processing. Some embodiments are used to transfer complex power to other industrial loads, such as plasma etching processes, scientific laboratory chamber waveform function generators, RADAR transmission, and industrial induction heating.

[0031] During the main plasma power deposition, at processing point 110, the waveform shape factor is determined according to equation (IV). The derivative of the power transmitted to the plasma chamber is pulsed. At processing point 120, a stable waveform shape factor is determined and stored. A stable waveform shape factor is when the waveform shape factor The stable waveform shape factor is determined when its derivative is close to 0. (This is based on the principle that the derivative of the waveform is 0.) The memory or firmware stored in the processing chamber, processing tool software, processing control server or mobile application, or stored inside the power supply itself.

[0032] In some implementations, a stable waveform shape factor It is preset or loaded into the system controller. For example, in chamber matching processing, the stable waveform shape factor of some implementations is determined by the "gold" chamber or reference processing. The preset stable waveform shape factor represents a specific pulse shape defined / developed for a specific plasma processing or a specific processing chamber.

[0033] In process 130, the waveform shape factor is continuously calculated during plasma processing. The waveform shape factor determined at any time t With the stable waveform shape factor stored in process 120 A comparison is made. In some implementations, the waveform shape change index I is calculated using equation (V). S .

[0034] In addition to the waveform shape factor defined in equations (III) and (IV) In addition, in some embodiments, other waveform or pulse characteristics are incorporated into more complex factorial formulas. For example, in some embodiments, the pulse frequency(s) F and its deviation (ΔF) relative to a requested value F0, the pulse on / off duty cycle (DT) and its deviation from the requested DT, the output power P and its deviation from the requested power P0, and the phase angle φ / phase angle variation Δφ. In some embodiments, any or all parameters are measured by sensors, internally or externally. In some embodiments, the measured variables are weighted (via a coefficient K, which is a multiplier) and added to... (Supplement) provides a broad picture of forming a comprehensive factor to indicate the quality and characteristics of the transmitted waveform. Equation (III) can be transformed into Equation (V).

[0035]

[0036] The last unspecified term (+...) refers to any additional parameters added to equation (V) depending on the specific processing conditions and the hardware used. Examples include secondary frequency, power, phase angle, etc.

[0037] ΔF(t) = F(t) - F0, where F(t) is the measured real-time frequency, and F0 is the moving average of the measured frequency or the predetermined input frequency for each application. ΔDT(t) = DT(t) - DT0, where DT(t) is the measured real-time duty cycle, and DT0 is the moving average or the predetermined value for each application. ΔP(t) = P(t) - P0, where P(t) is the measured real-time power, and P0 is the moving average or the predetermined value for each application.

[0038] S initA value >= 0 is a fixed, selected real number for a specific application, used to offset the baseline when necessary; it can be set to 0 or a smaller number (e.g., 10% or less) relative to the magnitude of the subtotal contribution in the equation. A value >0 can also help tune the sensitivity of S(t) signal monitoring. In some implementations, a higher relative value of the subtotal contribution to the remaining items reduces monitoring sensitivity.

[0039] Equation (V) can also be broken down into equations (V') and (V”).

[0040]

[0041]

[0042] Where K is 0 or another real number to indicate the weight of the effect of parameter changes. f K dt or K p All are set to 0, and K v When =1, then equation (V') simplifies to the basic form of equation (III).

[0043]

[0044] At decision point 140, evaluate the waveform shape factor index I. S This is to determine whether the value is within the predetermined tolerance value of the processing or processing chamber. If the waveform shape factor index I... S Within the tolerance range, method 100 continues at process 130, thereby continuing to determine the waveform shape factor. If the waveform shape factor index I S Beyond the predetermined tolerance, some implementations of the method warn the user of a fault or tolerance failure at point 150 and / or automatically stop the plasma processing.

[0045] exist Figure 3 In the method shown, the first two processes 110, 120 are determined using the same processing chamber and / or plasma treatment as the remainder of method 100. This method monitors deviations in the processing chamber and / or plasma treatment over time to ensure stable operation of the chamber.

[0046] Figure 4 Another implementation is illustrated, in which method 200 is used for chamber matching. At process 230, the waveform shape factor is determined. and with a predetermined waveform shape factor from the reference or "gold" chamber. Comparisons are made. Some implementations of the reference chamber include processing chamber hardware, processing equipment manufacturers, and / or processing methods.

[0047] At point 240, the calculated waveform shape change index I will be used. S Compare with the predetermined tolerance. If the waveform shape change index I... S If the error exceeds the tolerance, a fault message will be generated at processing point 250 and / or plasma processing will be stopped. A waveform shape change index exceeding the tolerance range indicates a mismatch between the chamber or plasma processing and the reference or "gold" processing chamber.

[0048] In some implementations, the waveform shape change index I S It is based on shape factor calculation and used for in-situ processing control to identify wafers that may have experienced problems caused by power failures or chamber hardware failures and / or performance drift resulting in changes in plasma load.

[0049] In some implementations, waveform shape factor and / or waveform shape change index I S It is incorporated into the power supply or waveform function generator to ensure that the power supply or waveform generator outputs a waveform shape relative to a predetermined or default shape. In some implementations, a waveform shape factor is used. and / or waveform shape change index I S Measurements fed into the power supply or waveform function generator provide control over the waveform shape without requiring additional measurement, sampling, and / or monitoring of the waveform output via an external sensing probe (sensor) / computer.

[0050] In some implementations, waveform shape factor and / or waveform shape change index I S The measurement system is integrated into the power supply (or waveform function generator) to provide self-diagnostic capabilities indicating instrument malfunctions. Therefore, as... Figure 5 As shown, some embodiments of this disclosure relate to a power supply 300 (or waveform function generator) incorporating a controller 310, which is configured to determine the waveform shape factor in real time. Or waveform shape change index I SOne or more of these. As used herein, the term "power supply" includes both conventional power modules and waveform function generators. In some embodiments, power supply 300 includes input / output (I / O) 320 to accept user input and provide feedback. In some embodiments, I / O 320 includes suitable components to allow the user to input a predetermined waveform shape factor or waveform shape change index. The data input component may be any suitable component known to those skilled in the art, including but not limited to a keypad 322 or a memory card reader 324. In some embodiments, I / O 320 includes a display 326 connected to a controller 310, and the controller 310 is configured to output the measured waveform shape factor or waveform shape change index to the display in real time or in predetermined time increments.

[0051] The controller 310 may be any form of general-purpose computer processor, microcontroller, microprocessor, etc., that can be used in an industrial environment. In some embodiments, at least one controller 310 is present. The at least one controller 310 may have a processor, memory connected to the processor, input / output devices 320 connected to the processor, and support circuitry for communication between different electronic components. The memory may include one or more of temporary memory (e.g., random access memory) and non-temporary memory (e.g., storage devices).

[0052] The processor's memory or computer-readable medium may be readily available memory, such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, or any other form of local or remote digital storage device. The memory may store an instruction set that can be operated by the processor to control system parameters and components. Supporting circuitry is coupled to the processor to support it in a known manner. This circuitry may include, for example, caches, power supplies, clock circuits, input / output circuits, subsystems, etc.

[0053] The processing can typically be stored in memory as a software routine, which, when executed by a processor, causes the processing chamber to perform the processing of this disclosure. The software routine can also be stored and / or executed by a second processor (not shown) remote from hardware controlled by the processor. Some or all of the methods in this disclosure can also be executed in hardware. Thus, the processing can be implemented in software and executed in hardware using a computer system, as, for example, an application-specific integrated circuit or other type of hardware, or as a combination of software and hardware. When executed by a processor, the software routine transforms a general-purpose computer into a dedicated computer (controller) that controls the operation of the chamber, causing the processing to be executed.

[0054] In some implementations, the controller has one or more configurations to perform individual processes or subprocesses to execute the method. The controller may be connected to intermediate components and configured to operate these intermediate components to perform the function of the method. For example, the controller may be connected to a power supply and configured to control the power or frequency of the power supply.

[0055] Throughout this specification, references to "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" refer to specific features, structures, materials, or characteristics described in connection with that embodiment, which are included in at least one embodiment of this disclosure. Therefore, terms such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment of this disclosure. Furthermore, in one or more embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner.

[0056] Although the disclosure herein has been described with reference to specific embodiments, those skilled in the art will understand that the described embodiments are merely illustrative of the principles and applications of this disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatus of this disclosure without departing from the spirit and scope of this disclosure. Therefore, this disclosure may include modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A method for controlling plasma processing, the method comprising the following steps: Determine the waveform shape change index during the deposition process; Determine whether the waveform shape change index is within a predetermined tolerance; as well as Determine the subsequent actions of the plasma treatment. The waveform shape change index is determined in real time using equation (VI). (WE), in It is the average waveform shape factor of the waveform shape measured during the deposition process. It is the average reference waveform shape factor of the preset waveform shape. The waveform shape measured during the deposition process and the preset waveform shape have the same average value. The average waveform shape factor It is calculated using equation (IV). (IV), The integral is from time 0 to time T. on The pulse length, and S(t) is the waveform shape factor. The waveform shape factor S(t) at time t is calculated using equation (III) or equation (V). (III) Where v(t) is the voltage, current, or power at time t, and v 平均 Is it average voltage, current, or power? (V)， Where S init >=0 and is a fixed selected real number. ΔF(t) = F(t) - F0, where F(t) is the measured real-time frequency, and F0 is the moving average of the measured frequency or the predetermined input frequency. ΔDT(t) = DT(t) - DT0, where DT(t) is the real-time duty cycle of the measurement, and DT0 is the moving average or predetermined value. ΔP(t) = P(t) - P0, where P(t) is the measured real-time power, and P0 is the moving average or predetermined value. K v K f K DT and K p These are weighting coefficients.

2. The method of claim 1, wherein the average reference waveform shape factor is determined by a first power pulse in the plasma processing.

3. The method of claim 2, wherein the waveform shape change index is a monitor of the deviation of the processing chamber and / or plasma processing over time to ensure stable operation of the processing chamber.

4. The method of claim 1, wherein the average reference waveform shape factor is determined by reference plasma processing or a reference processing chamber.

5. The method according to claim 4, wherein the waveform shape change index matches the target plasma processing or processing chamber with the reference plasma processing or reference processing chamber, respectively.

6. The method according to claim 1, wherein, If the waveform shape change index is within the predetermined tolerance, the subsequent actions include continuing the deposition process, repeatedly determining the waveform shape change index during the deposition process, repeatedly determining whether the waveform shape change index is within the predetermined tolerance, and repeatedly determining the subsequent actions of the deposition process.

7. The method according to claim 1, wherein, If the waveform shape change index is outside the predetermined tolerance, the subsequent actions include warning the user of a fault or tolerance fault, or automatically stopping one or more of the plasma processing.

8. A method for matching plasma treatment with a reference plasma treatment, the method comprising the steps of: The average waveform shape factor of the waveform measured during the plasma treatment is determined. ; Using the average waveform shape factor and the average reference waveform shape factor of the preset waveform shape from the reference plasma processing To determine the waveform shape change index I S ; as well as Based on the waveform shape change index I S Determine whether the plasma treatment matches the reference plasma treatment. The waveform shape change index I S It is determined in real time using equation (VI). (WE), The waveform shape measured during the plasma treatment and the preset waveform shape have the same average value. The average waveform shape factor It is calculated using equation (IV). (IV), The integral is from time 0 to time T. on The pulse length, and S(t) is the waveform shape factor. The waveform shape factor S(t) at time t is calculated using equation (III). (III), Where v(t) is the voltage, current, or power at time t, and v 平均 It is the average voltage, current, or power, or calculated using the equation (V). (V)， Where S init >=0 and is a fixed selected real number. ΔF(t) = F(t) - F0, where F(t) is the measured real-time frequency, and F0 is the moving average of the measured frequency or the predetermined input frequency. ΔDT(t) = DT(t) - DT0, where DT(t) is the real-time duty cycle of the measurement, and DT0 is the moving average or predetermined value. ΔP(t) = P(t) - P0, where P(t) is the measured real-time power, and P0 is the moving average or predetermined value. K v K f K DT and K p These are weighting coefficients.

9. The method of claim 8, wherein the step of determining whether the plasma treatment matches the reference plasma treatment includes the following steps: The waveform shape change index I S Compare with the predetermined tolerance.

10. The method according to claim 9, wherein, If the waveform shape change index is within the predetermined tolerance, the subsequent actions include continuing the plasma processing, repeatedly determining the waveform shape change index during the plasma processing, repeatedly determining whether the waveform shape change index is within the predetermined tolerance, and repeatedly determining the subsequent actions of the plasma processing.

11. The method according to claim 10, wherein, If the waveform shape change index is outside the predetermined tolerance, the subsequent actions include warning the user of a fault or tolerance fault, or automatically stopping one or more of the plasma processing.

12. A power supply including a self-diagnostic function indicating a fault, the self-diagnostic function including a controller configured to determine a waveform shape change index I. S , The waveform shape change index I is determined in real time using equation (VI). S (WE), in It is the average waveform shape factor of the waveform measured during plasma processing. It is the average reference waveform shape factor of the preset waveform shape. The average reference waveform shape factor is determined by a reference plasma process or a reference processing chamber, and the waveform shape measured during the plasma process has the same average value as the preset waveform shape. The average waveform shape factor It is calculated using equation (IV). (IV), The integral is from time 0 to time T. on The pulse length, and S(t) is the waveform shape factor. The waveform shape factor S(t) at time t is calculated using equation (III) or equation (V). (III) Where v(t) is the voltage, current, or power at time t, and v 平均 Is it average voltage, current, or power? (V)， Where S init >=0 and is a fixed selected real number. ΔF(t) = F(t) - F0, where F(t) is the measured real-time frequency, and F0 is the moving average of the measured frequency or the predetermined input frequency. ΔDT(t) = DT(t) - DT0, where DT(t) is the real-time duty cycle of the measurement, and DT0 is the moving average or predetermined value. ΔP(t) = P(t) - P0, where P(t) is the measured real-time power, and P0 is the moving average or predetermined value. K v K f K DT and K p These are weighting coefficients.

13. The power supply of claim 12, wherein the power supply further includes one or more inputs / outputs to accept user input and / or provide user feedback, said user feedback reporting one or more of a measured waveform shape factor or waveform shape change index.

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