Plasma processing device and working method thereof

Abstract

The invention discloses a plasma processing device and a working method thereof, and the plasma processing device comprises a vacuum reaction chamber which is internally provided with a lower electrode assembly comprising a first electrode; the pulse direct-current power supply is connected with the first electrode and applies pulse voltage to the first electrode, the pulse period of the pulse voltage comprises a first stage and a second stage, the pulse direct-current power supply applies first voltage to the first electrode in the first stage and applies second voltage in the second stage, and when the first stage is converted into the second stage, the pulse voltage is applied to the first electrode; and the pulse direct-current power supply outputs a proper voltage waveform to reduce the jump voltage when the first stage is converted to the second stage, so that the potential difference of a plasma sheath on the surface of the grounding end is reduced. The device has the advantages that by reducing the jump voltage during the first-stage and second-stage conversion, the ion impact energy of the grounding end is reduced, and the maintenance period of the grounding end is prolonged.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment, and more specifically to a plasma processing device and its operating method. Background Technology

[0002] In semiconductor device manufacturing, extensive micromachining is typically required. Currently, chemical vapor deposition (CVD) and physical vapor deposition (PVD) are commonly used processes for micromachining semiconductor components or substrates, such as in the manufacture of flexible displays, flat panel displays, light-emitting diodes (LEDs), and solar cells. The micromachining process is often accompanied by plasma-assisted processes, which are generally performed within a vacuum reaction chamber. Among these, plasma etching is a key process for shaping the substrate into the designed pattern. The working principle of plasma etching generally involves introducing a reactive gas containing an appropriate etchant or deposition source gas into the vacuum reaction chamber, followed by the input of radio frequency energy to activate the reactive gas, igniting or maintaining the plasma, thereby processing the substrate.

[0003] Throughout the plasma etching process, the reaction environment for substrate processing is extremely demanding. Factors such as the stability of the vacuum reaction chamber and its internal components, the stability of the internal process environment, and the pressure distribution within the chamber are all crucial, directly or indirectly determining the quality of the substrate surface treatment. However, in practical applications, due to various factors, the long-term stability of semiconductor process equipment is difficult to guarantee, leading to instability in the process environment. For example, during the process, the plasma environment within the chamber inevitably etches the grounding terminal to some extent. If the etching of the grounding terminal is too strong, it can easily damage the grounding terminal components, affecting their stability or lifespan, thus impacting the stability of the internal process environment. Therefore, improvements to existing equipment are necessary.

[0004] It is understood that the above statements only provide background information related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0005] Based on the aforementioned technical problems, the purpose of this invention is to provide a plasma processing device and its operating method. This plasma processing device can greatly reduce the potential difference of the plasma sheath layer on the grounding end surface during the etching process, thereby reducing the plasma etching intensity on the grounding end and increasing the maintenance cycle and service life of the plasma processing device.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A plasma processing apparatus, comprising:

[0008] A vacuum reaction chamber, wherein a lower electrode assembly is provided inside the vacuum reaction chamber, and a first electrode is disposed inside the lower electrode assembly;

[0009] A pulsed DC power supply, which is connected to the first electrode;

[0010] The pulsed DC power supply is used to apply a pulsed voltage to the first electrode. The pulse period of the pulsed voltage includes a first stage and a second stage. The pulsed DC power supply applies a first voltage to the first electrode in the first stage and applies a second voltage to the first electrode in the second stage. When transitioning from the first stage to the second stage, the pulsed DC power supply reduces the jump voltage when transitioning from the first stage to the second stage by outputting a suitable voltage waveform, thereby reducing the potential difference of the plasma sheath layer on the grounding end surface and reducing the ion bombardment energy at the grounding end.

[0011] Optionally, the pulsed DC power supply reduces the second voltage applied to the first electrode at the beginning of the second stage to reduce the jump voltage during the transition from the first stage to the second stage.

[0012] Optionally, during the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode exhibits an increasing trend.

[0013] Optionally, during the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode increases linearly.

[0014] Optionally, during the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode increases in a stepwise manner.

[0015] Optionally, the pulsed DC power supply applies a constant first voltage value to the first electrode during the first phase.

[0016] Optionally, during the first phase within a single pulse cycle, the first voltage value applied by the pulsed DC power supply to the first electrode exhibits a decreasing trend.

[0017] Optionally, during the first phase within a single pulse cycle, the first voltage value applied by the pulsed DC power supply to the first electrode decreases linearly.

[0018] Optionally, the first voltage is a negative voltage, and the second voltage is a positive voltage;

[0019] Alternatively, the first voltage may be a negative voltage, and the second voltage may be zero voltage;

[0020] Alternatively, the first voltage is a positive voltage, and the second voltage is a positive voltage.

[0021] Optional, also includes:

[0022] A source radio frequency power supply is used to provide source radio frequency voltage to the vacuum reaction chamber.

[0023] Optionally, the lower electrode assembly includes an electrostatic chuck and a base located below the electrostatic chuck, with the first electrode disposed within the electrostatic chuck.

[0024] Optionally, the first electrode includes a plurality of independent first sub-electrodes, each of which is arranged along the circumferential direction.

[0025] Optionally, the electrostatic chuck further includes a second electrode, which is connected to a DC power supply. The DC power supply is used to enable the second electrode to generate an electrostatic attraction force on the substrate.

[0026] Optionally, the first electrode and the second electrode may be disposed in the same plane or in different planes;

[0027] The first electrode and the second electrode are arranged in parallel.

[0028] Optionally, a method of operating the aforementioned plasma processing apparatus, the method comprising:

[0029] During the etching process, a pulsed DC power supply applies a pulsed voltage to the first electrode. The pulse period of the pulsed voltage includes a first stage and a second stage. The pulsed DC power supply applies a first voltage to the first electrode in the first stage and applies a second voltage to the first electrode in the second stage.

[0030] Specifically, during the transition from the first stage to the second stage, the voltage waveform output by the pulsed DC power supply is adjusted to reduce the jump voltage during the transition from the first stage to the second stage, thereby reducing the potential difference of the plasma sheath layer on the grounding end surface and reducing the ion bombardment energy at the grounding end.

[0031] Optional, also includes:

[0032] In the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode shows an increasing trend.

[0033] Optional, also includes:

[0034] The plasma processing apparatus further includes a source radio frequency power supply for providing a source radio frequency voltage to the vacuum reaction chamber, and the plasma concentration in the vacuum reaction chamber is adjusted by adjusting the source radio frequency voltage applied by the source radio frequency power supply.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] In a plasma processing apparatus and its operating method according to the present invention, the plasma processing apparatus outputs a suitable voltage waveform through a pulsed DC power supply to reduce the voltage jump value during the transition from the first stage to the second stage, thereby reducing the potential difference of the plasma sheath layer on the grounding terminal surface. This significantly reduces the ion bombardment energy to the grounding terminal, thus protecting it. This not only helps enhance the stability of the process environment but also extends the maintenance cycle and service life of the plasma processing apparatus. Furthermore, by suppressing the ion impact energy to the grounding terminal, the present invention can also reduce particle generation, thereby extending the cleaning cycle within the cavity.

[0037] Furthermore, in this invention, the second voltage value applied to the first electrode by the pulsed DC power supply in the second stage shows an increasing trend, which increases the potential difference of the plasma sheath layer on the ground end surface in at least some stages after the initial stage of the second stage. This helps to reduce the potential difference of the plasma sheath layer on the ground end surface throughout the second stage while ensuring that the etching intensity on the substrate remains unchanged. It reduces the potential difference of the plasma sheath layer on the ground end surface in the initial stage of the second stage, thereby reducing the etching intensity on the ground end while ensuring that the etching intensity on the substrate remains unchanged.

[0038] Furthermore, in this invention, the first voltage value applied to the first electrode by the pulsed DC power supply in the first stage tends to decrease, which helps to obtain a narrower ion energy distribution, thereby improving the quality of substrate processing. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a plasma processing device according to the present invention;

[0040] Figure 2 This is an equivalent circuit diagram of the pulsed DC power supply feeding plasma according to the present invention;

[0041] Figure 3 This is a schematic diagram of the control timing of the pulse voltage according to the first embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of the pulse voltage control timing according to the second embodiment of the present invention;

[0043] Figure 5 This is a comparative schematic diagram of the potential difference Vw of the plasma sheath layer on the grounding end surface in the first and second embodiments;

[0044] Figure 6 This is a schematic diagram of the pulse voltage control timing according to the third embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] It should be noted that, in this document, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Unless otherwise specified, an element defined by the phrase "comprising..." or "including..." does not exclude the presence of additional elements in the process, method, article, or terminal device that includes said element.

[0047] It should be noted that the accompanying drawings are all in a very simplified form and use non-precise ratios, and are only used to facilitate and clearly illustrate the purpose of the embodiments of the present invention.

[0048] like Figure 1The diagram shows a schematic of a plasma processing device according to the present invention. The plasma processing device includes: a vacuum reaction chamber 100, which is surrounded by a reaction chamber body and a chamber end cap 101. The reaction chamber body is typically made of a metallic material and includes a side wall 102 and a bottom wall 103. A substrate W transfer port (not shown) is provided on the side wall 102 for transferring the substrate W between the inside and outside of the vacuum reaction chamber 100. An evacuation port 104 is provided on the bottom wall 103 so that a vacuum pump can evacuate the interior of the vacuum reaction chamber 100 through the evacuation port 104. The vacuum reaction chamber 100 includes a lower electrode assembly 110 disposed at the bottom of the chamber. The lower electrode assembly 110 includes an electrostatic chuck 111 and a base 112 located below the chuck 111. The top of the chuck 111 includes a bearing surface for supporting the substrate W. The substrate to be processed, introduced into the vacuum reaction chamber 100 through a substrate transfer port, is placed on the top surface of the dielectric layer. Furthermore, the vacuum reaction chamber 100 also includes an upper electrode assembly 120 disposed opposite to the lower electrode assembly 110. The space between the upper electrode assembly 120 and the lower electrode assembly 110 is a processing area for processing the surface of the substrate W. The upper electrode assembly 120 includes a gas spray plate with multiple gas delivery channels. The gas spray plate is connected to a gas supply device, and the process gas from the gas supply device enters the vacuum reaction chamber 100 through the gas delivery channels of the gas spray plate.

[0049] Furthermore, the plasma processing apparatus also includes at least one source radio frequency (RF) power supply 130, which is connected to the upper electrode assembly 120 and / or the lower electrode assembly 110. The RF power supply 130 applies a high-frequency (HF) source RF voltage to the upper electrode assembly 120 and / or the lower electrode assembly 110 through a matching network to dissociate the process gas delivered into the cavity via the gas spray disk into plasma, thereby creating a plasma environment between the upper electrode assembly 120 and the lower electrode assembly 110 for etching. HF can be 13.56 MHz. This plasma environment contains a large number of active particles such as electrons, ions, excited-state atoms, molecules, and free radicals. These active particles can undergo various physical and / or chemical reactions with the surface of the substrate W to be processed, changing the morphology of the substrate W and thus completing the processing of the substrate W. In practical applications, the source RF voltage applied to the cavity by the source RF power supply 130 can be adjusted to regulate the plasma concentration within the vacuum reaction chamber 100.

[0050] To further improve the surface treatment quality of substrate W, the industry typically uses a bias RF power supply to provide low-frequency (LF) RF energy into the cavity, thereby generating a bias voltage on substrate W and accelerating the bombardment of substrate W by ions in the plasma. The LF can be 400kHz. However, since the low-frequency RF energy applied by the bias RF power supply is usually sinusoidal, ions entering the plasma sheath at different times experience different electric fields, resulting in a wide ion energy distribution. Etching by lower-energy ions exhibits strong isotropy, while etching by higher-energy ions exhibits strong anisotropy. During etching, especially in high aspect ratio structures, lower-energy ions have a larger divergence angle, easily causing bowing and tilting problems. Therefore, plasma processing devices using low-frequency bias RF power supplies struggle to achieve ideal etching morphologies, especially ideal high aspect ratio recessed structures, significantly limiting their applicability.

[0051] To address the aforementioned problems, in this invention, the low-frequency bias RF power supply is replaced with a DC power supply to bias the substrate W. Specifically, as shown... Figure 1 As shown, the plasma processing apparatus further includes a first electrode 113 and a pulsed DC power supply 140. The first electrode 113 is disposed within the lower electrode assembly 110, and the pulsed DC power supply 140 is connected to the first electrode 113 and applies a voltage to the first electrode 113 to improve the collimation of ion movement during the etching process of the substrate W. Figure 2 The diagram shown is an equivalent circuit diagram of the pulsed DC power supply 140 feeding plasma. Figure 2 In this context, C1 represents the capacitance between the first electrode 113 and the substrate W, with a capacitance value ranging from 1nF to 100nF. (D) SH C SH and R SH The parallel circuit represents the equivalent circuit model of the plasma sheath layer on the surface of substrate W. In some equivalent circuit models, a DC power supply can also be used to replace R. SH D W C W and R W The parallel circuit represents the equivalent circuit model of the plasma sheath layer on the surface of the grounding terminal (such as the gas spray disk, cavity sidewall 102). R pl This represents the resistance inside the plasma.

[0052] With the increasing demand for high aspect ratio etching, pulsed DC etching is commonly used in practical applications. For example, the source RF power supply 130 applies an RF voltage to the base 112 or the upper electrode assembly 120, and the pulsed DC power supply 140 applies a pulsed DC voltage to the first electrode 113. The intrinsic pulse period includes a first stage (such as...). Figure 3 S1 in the middle) and the second stage (such as Figure 3 In the first stage (S2), the pulsed DC power supply 140 applies a first voltage to the first electrode 113 to accelerate the plasma and obtain high-energy particles to bombard the surface of the substrate W to obtain a recessed structure, i.e., a deep hole; in the second stage, i.e. the residual ion compensation stage, the pulsed DC power supply 140 applies a second voltage to the first electrode 113, at which time the plasma sheath voltage is mainly distributed at the ground end.

[0053] During the etching process, a plasma sheath is formed between the plasma above the substrate W and the substrate W. This sheath causes the cations in the plasma to accelerate downwards and bombard the surface of the substrate W, thus etching the substrate W. The energy of the cations bombarding the substrate W is determined by the potential difference Vsh of the plasma sheath on the surface of the substrate W. Let the output voltage of the pulsed DC power supply 140 be V1, the plasma voltage be Vp, and the DC bias voltage above the substrate W be Vdc, then Vsh = Vp + Vdc - V1. Similarly, a plasma sheath is also formed on the surface of the grounding terminal (e.g., the cavity sidewall 102 or the gas spray disk). This plasma sheath causes the cations in the plasma to bombard the surface of the grounding terminal, damaging it. The energy of the cations bombarding the grounding terminal surface is determined by the potential difference Vw of the plasma sheath on the grounding terminal surface. At the grounding terminal, Vw = Vp. During the etching process, the plasma voltage Vp is generally not zero. Therefore, the plasma environment within the cavity inevitably etches the surface of the grounding terminal component to a certain extent, leading to corrosion or particle shedding and affecting its lifespan or stability, thus impacting the stability of the cavity's process environment. Existing equipment primarily addresses this issue by coating the grounding terminal component with a plasma-resistant protective layer. However, with increasingly stringent process requirements, this method is no longer sufficient to meet practical needs.

[0054] Based on the above, the applicant team started their research by examining the pulse voltage applied to the first electrode 113 by the pulsed DC power supply 140. By improving the logic of the output voltage of the pulsed DC power supply 140, they aimed to minimize damage to the grounding terminal. The applicant team discovered that during the entire etching process, the maximum potential difference Vw of the plasma sheath layer on the grounding terminal surface has the greatest impact on the etching depth of the grounding terminal component, i.e., it has the greatest impact on the degree of damage to the grounding terminal component. Therefore, it is necessary to reduce the maximum potential difference Vw of the plasma sheath layer on the grounding terminal surface during the process to reduce the maximum etching intensity on the grounding terminal, thereby mitigating the degree of damage to the grounding terminal. Based on this, in this application, the control logic of the output voltage of the pulsed DC power supply 140 has been adjusted. Specifically, during the transition from the first stage to the second stage, the pulsed DC power supply 140 outputs a suitable voltage waveform to reduce the jump voltage during the transition from the first stage to the second stage.

[0055] Further research by the applicant's team revealed that during the initial stage of the second phase of the entire process, the potential difference Vw of the plasma sheath layer on the grounding terminal surface is the largest. At this time, the ion bombardment energy to the grounding terminal is the highest, resulting in the strongest etching effect and the greatest likelihood of damage to the grounding terminal. In the period following the initial stage of the second phase, due to ion bombardment on the grounding terminal surface (equivalent capacitance discharge of the plasma sheath layer), the potential difference Vw of the plasma sheath layer on the grounding terminal surface gradually decreases. At the grounding terminal, Vw = Vp. However, the plasma voltage Vp in the initial stage of the second phase is actually the potential difference Vsh of the plasma sheath layer on the substrate W surface at the end of the first phase plus the voltage jump value. In this application, while ensuring that the voltage jump value during the transition from the second stage to the first stage remains unchanged (ensuring that the sheath voltage on the substrate W surface remains unchanged), the output waveform of the pulsed DC power supply 140 is changed to reduce the jump voltage during the transition from the first stage to the second stage. This reduces the potential difference Vw of the plasma sheath on the grounding terminal surface in the early stage of the second stage, thereby reducing the etching intensity on the grounding terminal surface in the early stage of the second stage. It also reduces the etching intensity on the grounding terminal throughout the etching process, which helps to improve the stability and service life of the grounding terminal component, thereby ensuring the stability of the process environment and the processing quality of the substrate W. It also helps to reduce the maintenance cycle of the plasma processing device. On the other hand, the present invention can suppress the ion bombardment energy to the grounding terminal, thereby reducing the generation of particles and extending the cleaning cycle within the cavity.

[0056] Furthermore, in practical applications, the second voltage applied to the first electrode 113 by the pulsed DC power supply 140 at the initial stage of the second phase can be adjusted to change the transition voltage during the transition from the first stage to the second stage. Specifically, the pulsed DC power supply 140 reduces the second voltage applied to the first electrode 113 at the initial stage of the second phase to reduce the transition voltage during the transition from the first stage to the second stage, thereby reducing the potential difference Vw of the plasma sheath layer on the grounding terminal surface and reducing the ion bombardment energy at the grounding terminal.

[0057] Furthermore, in the second stage, when the second voltage applied by the pulsed DC power supply 140 to the first electrode 113 is constant, the potential difference Vw of the plasma sheath on the grounding terminal surface will gradually decrease due to the discharge of the equivalent capacitance of the plasma sheath on the grounding terminal surface. For example, as... Figure 3 As shown, in the first embodiment, the pulsed DC power supply 140 applies a constant second voltage to the first electrode 113 in the second stage, and the potential difference Vw of the plasma sheath layer on the ground terminal surface gradually decreases in the second stage. On the other hand, in practical applications, if it is to ensure that the potential difference Vsh of the plasma sheath layer on the substrate W surface remains unchanged, i.e., the sheath voltage, it is necessary to keep the product of the potential difference Vw of the plasma sheath layer on the ground terminal surface constant with time in the second stage. Therefore, after reducing the potential difference Vw of the plasma sheath layer on the ground terminal surface in the early stage of the second stage, it is necessary to increase the value of the potential difference Vw of the plasma sheath layer on the ground terminal surface in at least a part of the stage after the initial stage of the second stage, that is, to increase the output voltage of the pulsed DC power supply 140 in the middle and late stages after the initial stage of the second stage.

[0058] Based on the above, in this application, while reducing the voltage jump value during the transition from the first stage to the second stage, in the second stage within a single pulse cycle, the second voltage value applied by the pulsed DC power supply 140 to the first electrode 113 exhibits an increasing trend. That is, the voltage jump is not zero in at least a portion of the stages after the initial stage of the second stage, thereby increasing the potential difference Vw of the plasma sheath layer on the ground terminal surface in at least a portion of the stages after the initial stage of the second stage. This ensures that the product of the potential difference Vw of the plasma sheath layer on the ground terminal surface and time remains constant, thus guaranteeing that the potential difference Vsh of the plasma sheath layer on the substrate W surface remains constant in the first stage. This reduces the etching intensity on the ground terminal while maintaining the etching intensity on the substrate W. On the other hand, since the potential difference Vw of the plasma sheath layer on the ground terminal surface is small after the initial stage of the second stage, even if the second voltage value exhibits an increasing trend in the second stage, it will not significantly increase the corresponding potential difference Vw of the plasma sheath layer on the ground terminal surface, i.e., it will not exceed the potential difference Vw of the plasma sheath layer on the ground terminal surface at the initial stage of the second stage, and will not increase the etching intensity on the ground terminal throughout the entire process.

[0059] Specifically, the second voltage value in the second stage can be in the form of a positive slope. That is, in the second stage within a single pulse cycle, the second voltage value applied by the pulsed DC power supply 140 to the first electrode 113 increases with time to increase the potential difference Vw of the plasma sheath layer on the ground terminal surface in at least a portion of the stage after the initial stage of the second stage. Optionally, the second voltage value can be made to increase linearly with time, which helps to improve the control accuracy of voltage regulation. The slope of this linear trend is defined as the first slope, which is proportional to the ion current received by the ground terminal (such as the cavity wall) divided by the plasma sheath capacitance of the ground terminal. That is, the first slope is positively correlated with the etching current on the substrate W surface and the grounding area of ​​the ground terminal. Generally, the ion current ranges from 1A to 100A, and the plasma sheath capacitance of the ground terminal ranges from 1nF to 50nF. In practical applications, a suitable first slope can be selected so that the product of the potential difference Vw of the plasma sheath layer on the ground terminal surface in the second stage and time is in the expected state (e.g., the same as the product of the two parameters in another embodiment with a larger voltage jump value during the transition between the first and second stages).

[0060] For example, such as Figure 3 and Figure 4 The diagram shows the control timing of the pulse voltage output by the pulsed DC power supply 140 in the first and second embodiments, respectively. It also includes the potential difference Vsh of the plasma sheath layer on the substrate W surface and the potential difference Vw of the plasma sheath layer on the ground terminal surface, simulated based on this pulse voltage. Figure 3 As shown, in the first embodiment, the second voltage applied by the pulsed DC power supply 140 to the first electrode 113 in the second stage is a constant value. In this embodiment, the potential difference Vw of the plasma sheath layer on the ground terminal surface gradually decreases in the second stage. Compared with the first embodiment, in the second embodiment, the second voltage value applied by the pulsed DC power supply 140 in the second stage is adjusted, specifically, as follows: Figure 4 As shown, the second voltage value applied by the pulsed DC power supply 140 to the first electrode 113 in the second stage increases linearly with a first slope to enhance the potential difference Vw of the plasma sheath at the ground terminal surface in at least a portion of the second stage after the initial stage. Figure 5 The image shows a waveform comparison of the potential difference Vw of the plasma sheath layer on the grounding terminal surface in the first and second embodiments. Figure 5It can be seen that even though the potential difference Vw of the plasma sheath layer on the ground terminal surface in the early stage of the second stage in the second embodiment is less than that in the first embodiment, the product of the potential difference Vw of the plasma sheath layer on the ground terminal surface in the early stage of the second stage remains the same throughout the second stage, due to the increasing trend of the second voltage value. That is, the product of the potential difference Vsh of the plasma sheath layer on the ground terminal surface in the first stage of the two embodiments and time is the same. Furthermore, since the duty cycle of each stage in the pulse period is the same in the two embodiments, the etching intensity of the substrate W in the first stage is the same in the two embodiments. Therefore, the present invention can reduce the etching intensity of the ground terminal while ensuring the etching intensity of the substrate W, thereby shortening the maintenance cycle of the ground terminal, avoiding adverse effects on the process due to ground terminal damage, and helping to improve the stability of the cavity environment. On the other hand, as shown in the second embodiment, by selecting a suitable first slope, the potential difference Vw of the plasma sheath layer on the ground end surface in the second stage can be kept constant. That is, the etching of the ground end in this stage is in a stable low etching intensity state. This method enhances the controllability of the etching of the ground end while ensuring the etching intensity of the substrate W.

[0061] On the other hand, in the second stage within a single pulse cycle, the second voltage value applied by the pulsed DC power supply 140 to the first electrode 113 can also increase in a stepwise manner, that is, have at least one voltage jump, so as to reduce the maximum value of the potential difference Vw of the plasma sheath layer on the ground end surface throughout the second stage, while maintaining the voltage jump value from the second stage to the first stage unchanged, thereby ensuring the etching intensity of the substrate W.

[0062] For example, such as Figure 6 The diagram shown is a control timing schematic of the third embodiment of the present invention. In the third embodiment, the second voltage value applied by the pulsed DC power supply 140 increases in a stepwise manner throughout the second stage, and the potential difference Vw of the plasma sheath layer on the ground terminal surface throughout the second stage exhibits a steep stepwise curve. Furthermore, the product of the potential difference Vw of the plasma sheath layer on the ground terminal surface in the second stage of the third embodiment and time is equal to the corresponding product in the first embodiment, meaning they have the same etching intensity on the substrate W. Figure 3 and Figure 6A comparison reveals that the step-like increase of the second voltage value in the second stage of the third embodiment effectively decomposes / evolves the single voltage jump during the transition from the first to the second stage in the first embodiment into several voltage jumps, thereby reducing the voltage jump amplitude during the transition between the first and second stages in the third embodiment. This method can reduce the etching intensity on the ground terminal while avoiding the adverse effects of large voltage jumps, helping to ensure the stability of the process environment and improving the stability of the ground terminal, as well as shortening its maintenance cycle. It is understandable that in practical applications, to achieve the same etching effect on substrate W, the more voltage jumps there are, the smaller the amplitude of each voltage jump can be.

[0063] It should be noted that the second voltage value output by the pulsed DC power supply 140 in the second stage can increase not only in the manner described above, but also in other forms, as long as the corresponding function can be achieved. This invention does not impose any limitations on this. For example, in another embodiment, the second voltage value applied by the pulsed DC power supply 140 to the first electrode 113 increases in an arc-like manner.

[0064] In practical applications, the pulsed DC power supply 140 can apply a constant first voltage value to the first electrode 113 in the first stage. This output method is simple to program and easy to adjust. However, with the development of semiconductor technology, the requirements for the processing quality of the substrate W are becoming increasingly stringent. To obtain an ideal etching morphology, the surface of the substrate W needs to have an almost constant voltage relative to the plasma to generate a narrow ion energy distribution (such as a single-peak ion energy distribution function). However, due to the capacitance between the first electrode 113 and the substrate W, in the first stage, the etching ion current will reduce the potential difference Vsh of the plasma sheath layer on the surface of the substrate W, thus making it impossible to obtain a single high-energy ion energy distribution function.

[0065] To address the aforementioned issues, in this embodiment, the first stage of the pulse voltage waveform is adjusted to compensate for the decrease in the potential difference Vsh of the plasma sheath layer on the substrate W surface caused by the etching ion flow, thereby obtaining a single high-energy ion energy distribution function. Specifically, in the first stage within a single pulse cycle of this invention, the first voltage value applied by the pulsed DC power supply 140 to the first electrode 113 exhibits a decreasing trend, so that the potential difference Vsh of the plasma sheath layer on the substrate W surface is kept as constant as possible, thereby obtaining a narrower ion energy distribution and improving the quality of substrate W processing.

[0066] Specifically, in the first phase within a single pulse cycle, the first voltage value applied by the pulsed DC power supply 140 to the first electrode 113 decreases linearly (see [link to relevant documentation]). Figure 4The first voltage value of the first stage is set as a ramp, and the slope of this ramp is defined as the second slope. This second slope is positively correlated with the etching current on the substrate W surface and negatively correlated with the magnitude of C1. In practical applications, by selecting an appropriate second slope, the potential difference Vsh of the plasma sheath layer on the substrate W surface can be kept constant in the first stage, thereby obtaining a single high-energy ion energy distribution function. Of course, the first voltage value output by the pulsed DC power supply 140 in the first stage can not only achieve the decreasing trend in the above manner, but also in other embodiments. This invention does not limit this to other methods.

[0067] As mentioned above, the potential difference Vsh of the plasma sheath layer on the substrate W surface is related to the jump voltage during the transition from the second stage to the first stage, and the potential difference Vw of the plasma sheath layer on the ground terminal surface is related to the jump voltage during the transition from the first stage to the second stage. Neither of these is related to the absolute magnitude or positive / negative characteristics of the first and second voltages. Therefore, this invention does not limit the absolute magnitude of the first and second voltages, nor does it limit their positive / negative characteristics (e.g., ...). Figure 4 The voltage pulse waveform in the image can be shifted in both positive and negative directions. That is, the first voltage is negative and the second voltage is positive; or, the first voltage is negative and the second voltage is zero; or, the first voltage is positive and the second voltage is positive.

[0068] On the other hand, to ensure that the pulse voltage applied by the pulsed DC power supply 140 to the first electrode 113 can be coupled to the substrate W, the first electrode 113 is preferably located close to the substrate W. For example... Figure 1 As shown, the first electrode 113 is disposed within the electrostatic chuck 111. Compared to disposing the first electrode 113 within the base 112, this method avoids the complex design required to ensure pulse voltage coupling to the substrate W, while also reducing the energy required for coupling. Optionally, the first electrode 113 may comprise multiple independent first sub-electrodes, each arranged circumferentially to adjust the plasma state in different regions, thereby addressing various DC bias compensation scenarios or process requirements of the substrate W. Further, the first electrode 113 composed of each first sub-electrode may correspond to the output terminal of one or more pulsed DC power supplies 140; this invention does not impose any limitations on this. For example, in one embodiment, the electrostatic chuck 111 is divided into multiple partitions circumferentially, each partition containing a first sub-electrode. One partition is a region near the transmission port of the substrate W. During the process, the first sub-electrode located in this region near the transmission port of the substrate W can be individually controlled to improve conditions such as asymmetry in the intracavity RF path or uneven plasma distribution caused by the transmission port of the substrate W.

[0069] Furthermore, the lower electrode assembly 110 also includes a second electrode 114, i.e., an adsorption electrode. The second electrode 114 is connected to a DC power supply 150, which is used to generate an electrostatic adsorption force between the second electrode 114 and the substrate W. Optionally, the first electrode 113 and the second electrode 114 can be arranged in the same plane or in different planes, i.e., they can be arranged vertically; on the other hand, the first electrode 113 can be arranged parallel to the second electrode 114. In practical applications, the arrangement can be made according to actual needs and installation conditions.

[0070] Based on the same inventive concept, the present invention also provides a method for operating a plasma processing device, the method comprising: during etching, a pulsed DC power supply 140 applies a pulsed voltage to a first electrode 113, the pulse period of the pulsed voltage comprising a first stage and a second stage, the pulsed DC power supply 140 applying a first voltage to the first electrode 113 in the first stage, and the pulsed DC power supply 140 applying a second voltage to the first electrode 113 in the second stage; wherein, when transitioning from the first stage to the second stage, the voltage waveform output by the pulsed DC power supply 140 is adjusted to reduce the jump voltage during the transition from the first stage to the second stage, thereby reducing the potential difference Vw of the plasma sheath layer on the grounding end surface and reducing the ion bombardment energy at the grounding end.

[0071] Furthermore, the method also includes: in the second stage within a single pulse cycle, the second voltage value applied by the pulsed DC power supply 140 to the first electrode 113 exhibits an increasing trend. In this manner, the etching intensity on the substrate W can be maintained while reducing the etching intensity at the ground terminal. Furthermore, while keeping the transition voltage value between the second and first stages constant, the potential difference Vsh of the plasma sheath on the surface of the substrate W also remains unchanged, which helps maintain the etching intensity on the substrate W.

[0072] Furthermore, the working method also includes adjusting the plasma concentration within the vacuum reaction chamber 100 by adjusting the source radio frequency voltage applied by the source radio frequency power supply 130.

[0073] In summary, in the plasma processing apparatus and its operating method of the present invention, the plasma processing apparatus outputs a suitable voltage waveform through a pulsed DC power supply 140 to reduce the voltage jump value during the transition from the first stage to the second stage, thereby significantly reducing the ion impact energy to the grounding terminal and protecting the grounding terminal. This not only helps to enhance the stability of the process environment but also extends the maintenance cycle and service life of the plasma processing apparatus. Furthermore, by suppressing the ion impact energy to the grounding terminal, the present invention can reduce particle generation, thereby extending the cleaning cycle within the cavity.

[0074] Furthermore, in the second stage, the second voltage applied by the pulsed DC power supply 140 to the first electrode 113 in the second stage shows an increasing trend, which increases the potential difference Vw of the plasma sheath layer on the ground end surface in at least a part of the second stage after the initial stage. This helps to reduce the potential difference Vw of the plasma sheath layer on the ground end surface throughout the second stage while ensuring that the etching intensity on the substrate W remains unchanged. It reduces the potential difference Vw of the plasma sheath layer on the ground end surface in the initial stage of the second stage, thereby reducing the etching intensity on the ground end while ensuring that the etching intensity on the substrate W remains unchanged.

[0075] Furthermore, in this invention, the first voltage value applied to the first electrode 113 by the pulsed DC power supply 140 in the first stage tends to decrease, which helps to obtain a narrower ion energy distribution, thereby improving the quality of substrate W processing.

[0076] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A plasma processing device, characterized in that, Include: A vacuum reaction chamber, wherein a lower electrode assembly is provided inside the vacuum reaction chamber, and a first electrode is disposed inside the lower electrode assembly; A pulsed DC power supply, which is connected to the first electrode; The pulsed DC power supply is used to apply a pulsed voltage to the first electrode. The pulse period of the pulsed voltage includes a first stage and a second stage. The pulsed DC power supply applies a first voltage to the first electrode in the first stage and applies a second voltage to the first electrode in the second stage. When transitioning from the first stage to the second stage, the pulsed DC power supply reduces the jump voltage when transitioning from the first stage to the second stage by outputting a suitable voltage waveform, thereby reducing the potential difference of the plasma sheath layer on the grounding end surface and reducing the ion bombardment energy at the grounding end.

2. The plasma processing apparatus as described in claim 1, characterized in that, The pulsed DC power supply reduces the second voltage applied to the first electrode at the beginning of the second stage, thereby reducing the jump voltage during the transition from the first stage to the second stage.

3. The plasma processing apparatus as described in claim 1, characterized in that, In the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode shows an increasing trend.

4. The plasma processing apparatus as described in claim 1 or 3, characterized in that, In the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode increases linearly.

5. The plasma processing apparatus as described in claim 1 or 3, characterized in that, In the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode increases in a stepwise manner.

6. The plasma processing apparatus as described in claim 1, characterized in that, The pulsed DC power supply applies a constant first voltage value to the first electrode during the first phase.

7. The plasma processing apparatus as described in claim 1, characterized in that, In the first phase within a single pulse cycle, the first voltage value applied by the pulsed DC power supply to the first electrode shows a decreasing trend.

8. The plasma processing apparatus as described in claim 1 or 7, characterized in that, In the first phase within a single pulse cycle, the first voltage value applied by the pulsed DC power supply to the first electrode decreases linearly.

9. The plasma processing apparatus as claimed in claim 1, characterized in that, The first voltage is a negative voltage, and the second voltage is a positive voltage; Alternatively, the first voltage may be a negative voltage, and the second voltage may be zero voltage; Alternatively, the first voltage is a positive voltage, and the second voltage is a positive voltage.

10. The plasma processing apparatus as claimed in claim 1, characterized in that, Also includes: A source radio frequency power supply is used to provide source radio frequency voltage to the vacuum reaction chamber.

11. The plasma processing apparatus as claimed in claim 1, characterized in that, The lower electrode assembly includes an electrostatic chuck and a base located below the electrostatic chuck, with the first electrode disposed within the electrostatic chuck.

12. The plasma processing apparatus as claimed in claim 11, characterized in that, The first electrode comprises a plurality of independent first sub-electrodes, each of which is arranged along the circumferential direction.

13. The plasma processing apparatus as claimed in claim 11, characterized in that, The electrostatic chuck also includes a second electrode, which is connected to a DC power supply. The DC power supply is used to enable the second electrode to generate an electrostatic attraction force on the substrate.

14. The plasma processing apparatus as described in claim 13, characterized in that, The first electrode and the second electrode are disposed in the same plane or in different planes; The first electrode and the second electrode are arranged in parallel.

15. A method of operating the plasma processing apparatus as described in any one of claims 1 to 14, characterized in that, The working method includes: During the etching process, a pulsed DC power supply applies a pulsed voltage to the first electrode. The pulse period of the pulsed voltage includes a first stage and a second stage. The pulsed DC power supply applies a first voltage to the first electrode in the first stage and applies a second voltage to the first electrode in the second stage. Specifically, during the transition from the first stage to the second stage, the voltage waveform output by the pulsed DC power supply is adjusted to reduce the jump voltage during the transition from the first stage to the second stage, thereby reducing the potential difference of the plasma sheath layer on the grounding end surface and reducing the ion bombardment energy at the grounding end.

16. The method of operating the plasma processing apparatus as described in claim 15, characterized in that, Also includes: In the second phase within a single pulse cycle, the second voltage value applied by the pulsed DC power supply to the first electrode shows an increasing trend.

17. The method of operating the plasma processing apparatus as described in claim 15, characterized in that, Also includes: The plasma processing apparatus further includes a source radio frequency power supply for providing a source radio frequency voltage to the vacuum reaction chamber, and the plasma concentration in the vacuum reaction chamber is adjusted by adjusting the source radio frequency voltage applied by the source radio frequency power supply.

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