Waveform shape coefficient of pulsed PVD power

Abstract

To provide apparatuses and methods to detect / increase / ensure pulsed PVD chamber deposition film performances if power / voltage / current waveforms change.SOLUTION: Power supplies, waveform function generators and methods for controlling a plasma process are described. The power supplies or waveform function generators include a component for executing the method, in which a waveform shape change index is determined during a plasma process, and the waveform shape change index is evaluated for compliance with a predetermined tolerance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of this disclosure generally relate to physical vapor deposition (PVD) chambers and methods. More specifically, embodiments of the disclosure relate to PVD chambers and deposition methods using pulsed PVD including a control power waveform. [Background technology]

[0002] Current physical vapor deposition (PVD) process chambers are susceptible to degradation of uniformity and reproducibility when power regulation changes. Power regulation is typically used to drive pulsed PVD plasma chambers using a voltage / current waveform of a certain shape. Such voltage / current waveforms are designed to achieve certain film characteristics or attributes.

[0003] As shown in Figure 1, the same average power, voltage, or current can be delivered as pulses with different waveform shapes. These different waveform shapes correspond to different plasma attributes within the PVD chamber. This power / voltage / current waveform shape drifts or changes dramatically due to chamber load conditions, plasma instability, chamber plasma arcing, or load changes, and sometimes due to power supply malfunctions and power delivery output cable hardware malfunctions. These waveform shape changes alter the chamber plasma conditions and therefore affect the thin film attributes. [Overview of the project] [Problems that the invention aims to solve]

[0004] Therefore, there is a need for apparatus and methods to detect, enhance, and guarantee the performance of pulsed PVD chamber deposited films when power / voltage / current waveforms change. [Means for solving the problem]

[0005] One or more embodiments of this disclosure relate to a method for controlling a plasma process. This method includes determining a waveform shape change index during a deposition process, determining whether the waveform shape index is within a predetermined tolerance range, and determining subsequent operations on the plasma process.

[0006] Additional embodiments of this disclosure relate to a method for aligning a plasma process to a reference plasma process. This method involves a waveform shape factor during the plasma process.

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[0007] Further embodiments of the present disclosure relate to a power supply equipped with a self-diagnostic function that indicates a malfunction. This self-diagnostic function uses waveform shape coefficients.

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[0008] To better understand the features of the present disclosure listed above, the disclosure briefly outlined above may be described more specifically by reference to embodiments in which some of them are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only typical embodiments of the present disclosure, and thus the accompanying drawings should not be regarded as limiting the scope of the present disclosure. This is because the present disclosure may accept other equally effective embodiments.

Brief Description of the Drawings

[0009] [Figure 1] It is a diagram showing a waveform shape according to one or more embodiments of the present disclosure. [Figure 2A] It is a diagram showing a waveform shape according to one or more embodiments of the present disclosure. [Figure 2B] It is a diagram showing a waveform shape according to one or more embodiments of the present disclosure. [Figure 2C] It is a diagram showing a waveform shape according to one or more embodiments of the present disclosure. [Figure 2D] It is a diagram showing a waveform shape according to one or more embodiments of the present disclosure. [Figure 3] It is a diagram showing a method according to one or more embodiments of the present disclosure. [Figure 4] It is a diagram showing a method according to one or more embodiments of the present disclosure. [Figure 5] It is a diagram showing a power supply according to one or more embodiments of the present disclosure.

Modes for Carrying Out the Invention

[0010] Before proceeding with the description of some exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited only to the details of the structures or process steps described in the following description. The present disclosure can include other embodiments and can be implemented or executed in various ways.

[0011] As used herein and in the appended claims, the term “substrate” refers to the surface or portion of a surface on which a process is performed. Furthermore, unless it is evident from the context otherwise, a statement to a substrate may also refer to only a portion of a substrate. Furthermore, a statement 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.

[0012] As used herein, “substrate” refers to any substrate or any material surface formed on a substrate on which a film treatment is performed during a manufacturing process. For example, substrate surfaces on which a treatment can be performed include, depending on the application, 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, as well as any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor wafers. A substrate can be subjected to a pretreatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, UV cure, e-beam cure, and / or bake the substrate surface. In addition to performing a film treatment directly on the surface of the substrate itself, the disclosed film treatment steps may also be performed on an underlying layer formed on the substrate, as will be disclosed in more detail later, and the term “substrate surface” is intended to include such underlying layers as the context indicates. Therefore, for example, when a film / layer or partial film / layer is deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0013] One or more embodiments of the present disclosure provide an apparatus and / or method for quantifying waveform distortion / change from a predetermined waveform shape or a default waveform shape during chamber operation. In some embodiments, the predetermined waveform shape or default waveform shape provides known plasma performance for films having specific attributes. In some embodiments, the default waveform shape or predetermined waveform shape is stored as a best known method (BKM) for a PVD chamber configuration.

[0014] In some embodiments, waveform shape factors are calculated based on measurements from the power supply's internal hardware and / or firmware. In some embodiments, the delivered voltage and / or current are sampled externally, and the waveform shape factors are calculated in real time by an external computer (one or more) that acquires data / information from the sensor.

[0015] In some embodiments, waveform coefficients are used to measure process chamber performance over time. In some embodiments, real-time measured waveform coefficients are compared to stored BKM waveform coefficients to evaluate PVD chamber performance. This real-time measurement comparison in some embodiments indicates whether the system has drifted or changed, or whether the system may be experiencing chamber matching issues that could affect chamber performance. In some embodiments, to enable chamber matching, the waveform coefficients of the process chamber are compared to stored waveform coefficients of a reference or "golden" chamber.

[0016] Referring to Figure 1, a rectangular voltage waveform (thick solid line) and a triangular waveform (dashed line) are shown as examples. As shown in equations (I) and (II), the mean voltage / average voltage in the pulses of both waveforms is the same. The overall shape of these pulses is different, and the falling triangular pulse has twice the peak voltage (V) of the rectangular waveform. peak ) has. The following examples discuss the voltage values ​​of these waveforms, but those skilled in the art will recognize that these values ​​may also represent waveform power or waveform current. Rectangle:

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[0017] Figures 2A, 2B, and 2D show other waveform shapes. Figure 2C shows the falling triangle shape shown in Figure 1 for comparison. In Figure 2A, when the shaded area of ​​the "W" shape below the V0 line is equal to the shaded area above the V0 line, the mean value is equal to V0. In Figure 2B, when the peak of the triangle is equal to twice the V0 value, the mean value is equal to V0. Figure 2C shows a falling triangle of the same shape as in Figure 1, with a peak value of twice V0 and a mean value equal to V0. Figure 2D shows another falling triangle shape in the opposite direction to Figure 2C, with a peak value of twice V0 and a mean value equal to V0. Each of the different waveforms shown in Figures 2A-2D has the same mean value (V) equal to the rectangular signal V0. mean ) has. However, the waveform shapes are all different.

[0018] To evaluate the differences between waveforms having the same average voltage, the waveform shape factor (S) can be determined using equation (III), and the average waveform shape factor (S) can be determined using equation (IV). avg or

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[0019]

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[0020] Using equations (III) and (IV), the theoretical average waveform coefficients of the rectangular waveform pattern shown in Figure 1 are obtained.

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[0021] The embodiments shown in Figures 2C and 2D appear mirror images of each other, but have different average waveform coefficients.

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[0022] Figure 3 shows Method 100 according to one or more embodiments of the present disclosure. Method 100 in some embodiments can be used to evaluate the drift of plasma processing chamber performance due to changes in plasma impedance resulting from arcing instability and / or plasma instability. In the methods described herein, the process is often discussed as a physical vapor deposition or PVD process. However, those skilled in the art will recognize that these methods are applicable to any plasma process and that the present disclosure is not limited to physical vapor deposition processes. In some embodiments, the method is used to address other commonly seen waveform shapes, including other forms of triangular, synusoidal, or envelope (modulated) shapes with numerous primary frequencies and amplitudes, which are not shown herein. Some embodiments of the present disclosure are used with semiconductor PVD processing. Some embodiments are used with complex power delivery to other industrial loads such as plasma etching, scientific laboratory waveform function generators, radar launching, and industrial induction heating.

[0023] During primary plasma power deposition, in process 110, while the power delivered to the plasma chamber is pulsed, the waveform shape coefficient is calculated according to equation (IV).

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[0024] In some embodiments, the stable waveform shape coefficient

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[0025] In process 130, during plasma processing, the waveform shape coefficient

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[0026] Waveform shape coefficients defined in equations (III) and (IV)

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[0027] [Number] (V)

[0028] The last term (+...) not specified indicates additional parameters added to Equation (V) according to the specific process conditions and hardware used. For example, second harmonic frequency, power, phase angle, etc.

[0029] ΔF(t) = F(t) - F0, where in this equation, F(t) is the measured real-time frequency and F0 is the moving average of the measured frequency or a predetermined input frequency for each application. ΔDT(t) = DT(t) - DT0, where in this equation, DT(t) is the measured real-time duty cycle and DT0 is the moving average value or a predetermined value for each application. ΔP(t) = P(t) - P0, where in this equation, P(t) is the measured real-time power and P0 is the moving average value or a predetermined value for each application.

[0030] S initFor values ​​≥ 0, a fixed real number selected for a specific application, used to offset the baseline as needed, can be set to 0, or a number small (e.g., less than 10%) relative to the magnitude of the nearly complete contribution of this expression. A value > 0 can further help to adjust the sensitivity of S(t) signal monitoring. In some embodiments, a higher relative value to the nearly complete contribution of the remaining items reduces monitoring sensitivity.

[0031] Equation (V) can be further divided into equations (V') and (V'').

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[0032]

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[0033] Judgment score 140, Waveform shape coefficient index I s The waveform shape coefficient index I is evaluated to determine whether this value is within the range of a predetermined tolerance value for the process or process chamber. s If it is within the tolerance range, method 100, in process 130, the waveform shape coefficient

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[0034] In the method shown in Figure 3, the first two processes 110 and 120 are determined using the same process chamber and / or plasma process as the remaining processes of method 100. This type of method monitors the process chamber and / or plasma process with respect to deviations over time to ensure stable operation of the process chamber.

[0035] Figure 4 shows another embodiment in which method 200 is used for chamber matching. In process 230, the waveform shape coefficient

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[0036] In process 240, the calculated waveform shape change index I s Compare this to a predetermined tolerance. Waveform shape change index I s However, if the value is greater than the tolerance or outside the tolerance range, process 250 generates a fault message and / or stops the plasma process. A waveform shape change index outside the tolerance range indicates that the chamber or plasma process is not conforming to the process standard or the "golden" chamber.

[0037] In some embodiments, the waveform shape change index I s Based on the calculation of the shape coefficient, the waveform shape change index I sHowever, it is used in in-process control to identify wafers that may have experienced problems caused by power supply failure or chamber hardware failure, and / or performance drift that caused plasma load changes.

[0038] In some embodiments, a waveform shape coefficient is used to ensure that the power supply or waveform generator outputs a waveform shape for a predetermined or default shape.

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[0039] In some embodiments, a self-diagnostic function that identifies malfunctions in the equipment is provided, including waveform shape coefficients.

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[0040] The controller 310 can be one of any form of general-purpose computer processor, microcontroller, microprocessor, etc., that can be used in an industrial setting. In some embodiments, there is at least one controller 310. The at least one controller 310 may have a processor, memory coupled to the processor, input / output devices 320 coupled to the processor, and support circuits for communication between different electronic components. The memory may include one or more transient memory (e.g., random access memory) and non-transient memory (e.g., storage).

[0041] The processor's memory or computer-readable medium can be one or more readily available local or remote memories, such as random access memory (RAM), read-only memory (ROM), floppy disks, hard disks, or any other form of digital storage. The memory can hold a set of instructions executable by the processor to control the system's parameters and components. Supporting circuits are coupled to the processor to support it in a conventional manner. These circuits may include, for example, caches, power supplies, clock circuits, input / output circuits, subsystems, and so on.

[0042] The process can generally be stored in memory as a software routine that, when executed by a processor, causes the process of the disclosed process to be executed in a process chamber. This software routine may also be stored and / or executed by a second processor (not shown) located remotely from the hardware controlled by that processor. Some or all of the methods of the disclosed method can also be executed in hardware. Thus, the process can be implemented in software and executed using a computer system, or in hardware, for example, as an application-specific integrated circuit or other type of hardware implementation, or as a combination of software and hardware. When executed by a processor, the software routine transforms a general-purpose computer into a purpose-specific computer (controller) that controls the operation of the chamber so that the process can be executed.

[0043] In some embodiments, the controller has one or more configurations for executing individual processes or subprocesses for performing the method. The controller can be connected and configured to operate intermediate components for performing the function of the method. For example, the controller can be connected and configured to control the power or frequency of a power supply.

[0044] Throughout this Specification, any reference to “one embodiment,” “certain embodiments,” “one or more embodiments,” or “embodiment” means that the specific features, structures, materials, or properties described in relation to that embodiment are included in at least one embodiment of this Disclosure. Therefore, the appearance of phrases such as “in one or more embodiments,” “certain embodiments,” “in one embodiment,” or “in an embodiment” in various parts of this Specification does not necessarily relate to that same embodiment of this Disclosure. Furthermore, in one or more embodiments, those specific features, structures, materials, or properties can be combined in any appropriate manner.

[0045] While this specification has described the disclosure with reference to specific embodiments, those skilled in the art will understand that the embodiments described are merely examples of the principles and applications of the 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 the disclosure without departing from the spirit and scope of the disclosure. Accordingly, the disclosure may include modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A power supply equipped with a self-diagnostic function that identifies malfunctions, configured to supply power to a process chamber on which a plasma process is performed, wherein the self-diagnostic function calculates the average waveform shape coefficient and the average reference waveform shape coefficient from the waveform shape coefficient S(t) at time t, using equation (VI) [Math 1] Using the waveform shape change index I s Includes a controller configured to determine in real time, In the above equation, [Math 2] This is the average waveform shape coefficient, [Math 3] A power supply in which the average reference waveform shape coefficient is calculated by integrating the waveform shape coefficient S(t) at time t over the pulse length from time 0 to time Ton and dividing by the pulse length, and the average reference waveform shape coefficient is similarly calculated in a reference plasma process or reference processing chamber, and the controller determines whether the waveform shape change index I s is within a predetermined tolerance range.

2. The controller uses equation (III) or equation (V) to determine the waveform shape coefficient S(t) at time t. [Math 4] 【number】 The power supply according to claim 1, further configured to perform calculations using

3. The power supply according to claim 2, further comprising one or more inputs / outputs for accepting user input and / or providing user feedback reporting one or more of the measured waveform shape coefficients or waveform shape change index I s.

4. The aforementioned average waveform coefficient [Math 5] However, equation (IV) [Math 6] Calculated using the above formula, the integral is calculated from time 0 to time T on The power supply according to claim 2, wherein the pulse length is up to and S(t) is the waveform shape coefficient.

5. The power supply according to claim 4, wherein the average reference waveform shape coefficient is determined from the first power pulse of the reference plasma process.

6. The power supply according to claim 5, wherein the waveform shape change index I s is a monitoring index for monitoring the process chamber and / or a reference plasma process with respect to deviations over time in order to ensure the stable operation of the process chamber.

7. The power supply according to claim 4, wherein the average reference waveform shape coefficient is determined from a reference plasma process or a reference processing chamber.

8. The power supply according to claim 7, wherein the waveform shape change index I s aligns the target plasma process or processing chamber with the reference plasma process or reference processing chamber, respectively.

9. The power supply according to claim 4, wherein the controller is further configured to notify the user of the presence of a fault or tolerance failure, or to automatically stop the plasma process, when the waveform shape change index I s is outside the range of a predetermined tolerance.

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