Highly selective, low stress, and low hydrogen diamond-like carbon hard mask generated by high-power pulsed low-frequency RF

Abstract

The present invention provides methods and related apparatus for depositing an ashable hard mask (AHM) on a substrate by pulsing a low-frequency radio frequency portion at high power. Pulsing the low-frequency power can be used to increase the selectivity of the AHM or reduce the stress of the AHM. The AHM can then be used to etch features into the underlying layers of the substrate.

Description

[0001] Incorporated by Reference

[0002] The PCT application form is filed concurrently with this specification as a part of this application. Each application to which this application claims the benefit of or priority as identified in the concurrently filed PCT application form is incorporated herein by reference in its entirety and for all purposes. Background Art

[0003] In semiconductor processing, including in memory and logic device manufacturing, amorphous carbon films can be used as hard masks and etch stop layers. These films are also called ashable hard masks (AHMs) because they can be removed by ashing techniques. As aspect ratios increase in photolithography, AHMs require higher etch selectivity. Current methods of forming highly selective AHMs using plasma-enhanced chemical vapor deposition (PECVD) result in AHMs with high stress, which limits the use of AHMs as hard masks. Therefore, there is a need to produce AHMs with high etch selectivity but low stress.

[0004] The descriptions of background and context contained herein are provided solely for the purpose of presenting the context of the disclosure as a whole. Many of the present disclosures are the work of the inventors, and simply because such work is described in the background section or presented as context elsewhere in this document does not mean that it is admitted to be prior art. Summary of the Invention

[0005] Disclosed herein are methods and systems for depositing an ashable hard mask (AHM) film by plasma-enhanced chemical vapor deposition (PECVD) with reduced stress levels and increased etch selectivity. In various embodiments, the method may involve exposing a substrate to a process gas containing a hydrocarbon precursor and generating a plasma by pulsing low-frequency (LF) power using dual radio frequency (RF) sources. Pulsing the LF power at high power, high frequency, and low duty cycle (DC) can increase the modulus of the AHM film and, therefore, increase the selectivity of the AHM film. A carrier gas consisting primarily of helium can also reduce sputtering of the AHM film.

[0006] In one aspect of the embodiments herein, a method of forming an ashable hard mask (AHM) film is provided, which may include: exposing a semiconductor substrate to a process gas, which may include a hydrocarbon precursor gas and helium, substantially without any other inert gas; and depositing the AHM film on the semiconductor substrate by a plasma enhanced chemical vapor deposition (PECVD) process, wherein the process includes: igniting a plasma generated by a dual radio frequency (RF) plasma source including a high frequency (HF) portion and a low frequency (LF) portion, the HF power being constant during deposition and the LF power being pulsed at at least about 3000 W per 300 mm wafer and a duty cycle between about 10% and about 75%.

[0007] In some implementations, the hydrocarbon precursor gas can include a compound having a molecular weight of up to about 50 g / mol. In some implementations, the hydrocarbon precursor gas can include a compound having a C:H ratio of at least 0.5. In some implementations, the hydrocarbon precursor gas can include acetylene (C2H2). In some embodiments, the hydrocarbon precursor gas has a partial pressure of between about 1-2% of the process gas.

[0008] In various embodiments, the LF power is provided at a frequency of less than or equal to about 2 MHz. In various embodiments, the LF power is between about 3500 W and about 6500 W per 300 mm wafer. In some embodiments, the LF power is pulsed at a frequency of at least about 100 Hz. In some embodiments, the LF power is pulsed at a frequency between about 100 Hz and about 1000 Hz.

[0009] In some embodiments, the LF power has a duty cycle between about 10% and about 50%. In various embodiments, the LF power has a duty cycle between about 60% and about 90%. In various implementations, the LF power has an on-time duration between about 200 microseconds and about 300 microseconds. In some embodiments, the method can be performed in a multi-station reactor.

[0010] In various implementations, the AHM film has an internal stress of at most about -1400 MPa. In various embodiments, the AHM film has a modulus of at least about 80 GPa. In some embodiments, the AHM film has a density of at least about 1.5 g / cm 3 .

[0011] In some implementations, the AHM film has a hydrogen concentration of at most about 25 atomic %. In various embodiments, the AHM film has a thickness of at most about 2500 nm. In some embodiments, the gap between the susceptor and the showerhead is less than about 20 mm.

[0012] In some embodiments, the method may further include patterning the deposited AHM film and etching the patterned AHM film to define features of the AHM film in the substrate. In various embodiments, the method may further include etching a layer in the substrate below the AHM film.

[0013] In another aspect of the embodiments herein, a method of forming an ashable hard mask (AHM) film is provided, which may include: exposing a semiconductor substrate to a process gas, wherein the process gas may include a hydrocarbon precursor gas and an inert gas; and depositing the AHM film on the semiconductor substrate by a plasma enhanced chemical vapor deposition (PECVD) process, wherein the process may include: igniting a plasma generated by a dual radio frequency (RF) plasma source including a high frequency (HF) portion and a low frequency (LF) portion, wherein the HF power is constant during deposition, and the LF power is pulsed at a level of at least about 3000 W per 300 mm wafer and with an LF power on time of less than 300 microseconds per duty cycle.

[0014] In some implementations, the LF power has a duty cycle between about 10% and 50%. In various embodiments, the LF power on time is between 200 microseconds and 300 microseconds. In some implementations, the LF power is pulsed at a frequency of at least 100 Hz.

[0015] These and other features will be described in more detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart illustrating method operations associated with using an ashable hard mask in an etch operation according to various embodiments.

[0017] Figure 2A and 2B is an illustration of line bending of a patterned ashable hard mask.

[0018] Figure 3 A flow chart illustrating method operations associated with forming an ashable hard mask by modulating a dual RF plasma generator according to various embodiments.

[0019] Figure 4A -C is a graph showing various properties related to pulsing low frequency (LF) power.

[0020] Figure 5 A graph showing the refractive index of an ashable hard mask as a function of LF power for various embodiments is shown.

[0021] Figure 6A graph showing the refractive index of an ashable hard mask as a function of stress for various embodiments is shown.

[0022] Figure 7 A schematic diagram of a plasma enhanced chemical vapor deposition (PECVD) chamber suitable for practicing various embodiments is shown.

[0023] Figure 8 Another schematic diagram of another plasma enhanced chemical vapor deposition (PECVD) chamber suitable for practicing various embodiments is shown.

[0024] Figure 9 Schematic diagrams showing clusters of modules suitable for implementing various embodiments are shown. DETAILED DESCRIPTION

[0025] Introduction and Background

[0026] In semiconductor processing, masking methods are used to pattern and etch substrates. As the aspect ratio of substrates increases, the need for highly selective hard masks also increases. Masks with high etch selectivity but that are easy to remove without damaging the substrate are important for processing substrates. Ashable hard masks (AHMs) can be used as masks in etch stop layers or during selective etching, or in situations where the photoresist may not be thick enough to mask the underlying layers. AHMs can also be used on glass substrates used for displays and other technologies.

[0027] AHM films have a chemical composition that allows them to be removed once they have served their purpose by techniques known as "ashing," "plasma ashing," or "dry stripping." An example of an AHM film is an amorphous carbon layer or film. AHM films are typically composed of carbon and hydrogen and optionally trace amounts of one or more dopants such as nitrogen, fluorine, boron, and silicon. The bonding structure of an AHM can be sp 2 (graphite-like) or sp 3 (diamond-like carbon), or a combination thereof, depending on the deposition conditions.

[0028] Figure 1 A flowchart illustrating related method operations for using an ashable hard mask in an etching operation according to various embodiments. Although the following description primarily refers to semiconductor substrates, the method can also be applied to layers on other types of substrates, including glass substrates. Examples of materials that can be masked using an AHM include dielectric materials such as oxides (e.g., SiO2) and nitrides (e.g., SiN and TiN), polycrystalline silicon (poly-Si), and metals such as aluminum (Al), copper (Cu), and tungsten (W). In several embodiments, the AHM described herein is used to pattern oxide, nitride, or poly-Si layers.

[0029] In operation 102, an ashable hard mask is deposited on the layer to be etched by plasma-enhanced chemical vapor deposition (PECVD). The PECVD process involves generating a plasma in a deposition chamber. As further described below with reference to FIG. 2 , a dual radio frequency (RF) plasma source comprising high frequency (HF) power and low frequency (LF) power can be used. In some processes, one or more AHM layers are deposited.

[0030] In operation 106, a photoresist layer is deposited, exposed, and developed according to the desired etch pattern. In some embodiments, an antireflective layer (ARL) can be deposited on the AHM film prior to photoresist deposition.

[0031] In operation 108, the AHM film is opened by etching the exposed portion of the AHM. The opening of the AHM may be performed by a fluorine-rich dry etch.

[0032] Next, in operation 110, the substrate layer is selectively etched to transfer the pattern to the substrate layer. The selective etching may be performed such that the substrate layer is etched without substantially cutting the AHM wall. Examples of etching may include free radical-based and / or ion-based etching. Examples of etching chemicals may include halogen-based etching chemicals, such as fluorine-containing and chlorine-containing etching chemicals. For example, a capacitively coupled plasma generated from a fluorocarbon-containing process gas may be used to selectively etch an oxide layer. Specific examples of process gases include C-containing gas optionally accompanied by oxygen (O2) and an inert gas. x F y Process gas, such as C4H8 / CH2F2 / O2 / Ar.

[0033] Finally, in operation 112, a technique known as ashing, plasma ashing, or dry stripping is used to remove the AHM. Ashing can be performed using an oxygen-rich dry etch. Typically, oxygen is introduced into the chamber under vacuum, and RF power generates oxygen radicals in the plasma to react with the AHM and oxidize it into water (H2O), carbon monoxide (CO), and carbon dioxide (CO2). Optionally, any remaining AHM residue can also be removed by a wet or dry etch process after ashing. The result is a patterned substrate layer.

[0034] High aspect ratio patterning utilizes AHMs with high etch selectivity. Etch selectivity can be determined by comparing the etch rate of an AHM layer to the underlying layer. Etch selectivity can sometimes be approximated by determining the hydrogen content, refractive index (RI), density, and modulus, or stiffness, of the AHM layer. Generally, AHMs with lower hydrogen content, lower RI, higher density, and higher modulus, or greater stiffness, can withstand higher etch rates in etch processes involving more ion bombardment. Therefore, AHMs with lower hydrogen content, lower RI, higher density, and / or higher modulus have higher selectivity and lower etch rates and can be used more efficiently and effectively to process high aspect ratio semiconductors. The desired etch selectivity of the AHM may depend on the etch process and the composition of the underlying layer, but the correlation between etch selectivity and the above material properties remains the same regardless of the etch process and the composition of the underlying layer. The selectivity correlations described herein apply to all types of underlying layers, including polysilicon layers, oxide layers, and nitride layers.

[0035] It has been observed that AHM films produced using continuous wave (CW) LF and HF plasmas can have several issues. For example, they can have relatively high internal stress, high hydrogen content, low density, and / or low hardness / modulus. The continued shrinking feature sizes of next-generation memory and logic applications require that the features do not exhibit noticeable line bending or distortion after the pattern has been etched into the film stack. Figure 2A -B is a diagram illustrating line bending of photoresist. Figure 2A A feature 200 of a patterned AHM is shown having a height or thickness "h" and a width "w." Figure 2A There is no line bending, which is an ideal condition for the characteristics of AHM. Figure 2B The same feature is shown, but with line bending, which may have a vertical aspect 223 and a horizontal aspect 225. As shown, line bending can be manifested as a horizontal component that is curved, angled, or otherwise bent. In some cases, line bending is manifested as a vertical component that deviates from a plane perpendicular (orthogonal) to the substrate on which the line is formed. In the depicted embodiment, the line has a fan shape. Line bending is undesirable for a number of reasons, particularly because line bending increases line edge roughness (LER) and line width roughness (LWR), and reduces the critical dimension uniformity (CDU) of the AHM and the underlying layers etched using the AHM. In general, line bending can cause feature distortion after the pattern has been etched into the film stack.

[0036] The line bending of AHM can be roughly modeled by the following equation:

[0037]

[0038] where σ and E are the internal compressive stress and modulus of the AHM, respectively. This equation shows that line bow is directly related to stress and height, increasing with increasing stress or height (i.e., thickness), but inversely related to modulus and width, decreasing with increasing modulus or width. As feature sizes shrink, the width of the AHM feature decreases to meet the new critical dimension requirements. Furthermore, the width of the AHM required for the etch process is inversely proportional to its selectivity; higher selectivity allows for thinner AHMs, and lower selectivity requires thicker AHMs. Therefore, line bow can be reduced by reducing stress, increasing modulus, or reducing thickness, but reducing thickness requires increasing selectivity.

[0039] Highly selective AHM films typically have high stress levels. Some methods for forming AHMs use continuous wave RF power plasma in a PECVD process. Using continuous wave RF power results in continuous ion bombardment, which increases film density by creating more sp atoms between carbon atoms. 3 However, continuous ion bombardment can also cause excess unbonded hydrogen atoms in the film to bind and modify the growing film through ion bombardment with heavy atomic weight ions. These effects can increase the stress of the deposited AHM film, thereby limiting AHM applications, as high-stress AHMs are more likely to exhibit line bending.

[0040] On the other hand, AHMs with low stress levels and concomitantly less wire bending have lower selectivity. Some methods of forming AHMs pulse the RF power plasma during the PECVD process. Pulsing the RF power results in pulsed ion bombardment, which reduces stress levels and, in turn, wire bending. However, pulsed ion bombardment may also reduce sp 3 The number of bonds increases, which results in lower density and lower selectivity. For the same etch process, lower selectivity requires a thicker AHM, which increases the amount of line bending.

[0041] According to various embodiments, methods for forming an AHM produce films with high selectivity and low stress. The AHM film deposition technique uses low-frequency (LF) RF pulsing (with or without continuous-wave (CW) high-frequency (HF) RF) at high single-station LF power to reduce the internal stress (making it more stress-neutral), reduce hydrogen content, and increase selectivity in diamond-like carbon (DLC) films that can be used as AHMs. These methods produce AHMs with improved selectivity for a given stress level, or reduced stress levels for a given selectivity, thereby improving AHM performance in semiconductor processing.

[0042] In various embodiments, an AHM deposition technique uses low-frequency (LF) RF pulsing (with or without continuous-wave (CW) high-frequency (HF) RF) at high single-station LF power to reduce internal stress (making it more stress-neutral), reduce hydrogen content, and increase selectivity in diamond-like carbon (DLC) films when used as an ashable hard mask (AHM). There are three main components to this process. First, high LF power can be used at each station. In various embodiments, the total process range is 3500W to 6500W of LF power per station, with significant stress reduction and densification of the DLC film. Second, a carrier gas containing essentially only helium is used. For uniformity, argon is typically used to help contain the plasma. However, argon ions can sputter the AHM at high ion energies, reducing density and selectivity. Third, the fast pulsing frequency and low duty cycle result in a short LF "on time," allowing the plasma to increase peak ion energy while maintaining a low average ion density. In other words, due to the fast LF pulsing, there are fewer ions with higher energy than in a continuous wave plasma.The benefits of high LF power are most pronounced when pulsing is employed.

[0043] Certain embodiments use relatively fast (greater than 100 Hz at 25% duty cycle) LF pulsing at high per-station LF power in a He / hydrocarbon precursor atmosphere only, with or without CW HF.

[0044] Figure 3 A flow chart of related method operations for forming an AHM by modulating dual RF plasma power according to various embodiments is shown. In operation 302, a substrate is received in a processing chamber. The substrate can be provided to the chamber during this operation, or the substrate can already be in the chamber from a previous operation. In operation 304, the substrate is exposed to a process gas containing a hydrocarbon precursor. In addition to hydrocarbon precursors, an inert gas carrier can also be used. The inert gas can include helium (He), argon (Ar), nitrogen (N2), hydrogen (H2), or a combination of any of these. In some embodiments, the inert gas is substantially entirely helium.

[0045] Next, in operation 306, an ashable hard mask is deposited on the substrate via a PECVD process by igniting a plasma using a dual RF plasma source to generate a plasma having a pulsed low frequency (LF) portion and a high frequency (HF) portion. The pulsed LF portion can be generated by pulsing the LF power source. In some embodiments, pulsing the LF RF power includes using high power, rapid pulses, and a low duty cycle to generate high peak energy ion bombardment with a low average ion density.

[0046] The result of operation 306 is an AHM film. This process produces a film with a more optimal density-to-stress ratio and higher selectivity. Depending on the duty cycle of the LF power, the pulsing frequency can be adjusted to maintain a high average ion energy while varying the average ion density. In some embodiments, the DC can be reduced to produce a low-modulus, low-stress film. In other embodiments, the DC can be increased to produce a high-modulus, high-stress film. Increasing the DC can also increase the deposition rate of the AHM film. Both types of films can be desirable, depending on other processing conditions.

[0047] Suggestion Mechanism

[0048] Figure 4A -C presents how pulsing the LF power can improve the deposition results of AHM deposits. Figure 4A The pulsed LF power and associated duty cycle are shown relative to time. At time 402, the LF power is turned on, or set to high power, and at time 404, the LF power is turned off, or set to low power. As shown and as is known in the art, the duty cycle is given by the equation DC = t on / (t on +t off ) and represents the percentage of time the power is on or set to high power. Duty cycle and pulse frequency can be used together to determine when the LF power is on. For example, a 100Hz pulse frequency with a 25% duty cycle means the LF power is on for 2.5ms and off for 7.5ms.

[0049] Figure 4B Schematic diagrams of the substrate surface during AHM deposition with LF power turned on and off according to a possible mechanism for forming an AHM film according to the present disclosure. State 410 shows the substrate surface with LF power on. LF power generally energizes the ion portion of the plasma, and with LF power on, carbon ions 412 bombard the substrate surface. As discussed above, ion bombardment can increase density, but a higher density of charged ions can also undesirably increase stress in the AHM and may also form a charged surface 414. State 420 shows possible conditions on the substrate surface with LF power off. When LF power is off, ion bombardment ceases or is significantly reduced, and ions embedded in the substrate surface absorb electrons 422 to generate a neutral charge. While not wishing to be bound by theory, this allows the ions to form a more ordered structure 424, thereby reducing stress within the substrate surface, which is desirable. However, this reduction in stress may come at the expense of reduced density (and therefore selectivity). By pulsing the LF power, the surface can be changed between states 410 and 420 to deposit an AHM with reduced internal stress.

[0050] Figure 4CFigure 4 is a graph of plasma temperature over time, where temperature is measured in electron volts. When LF power is pulsed, there is a brief high ion energy spike 442 at the time of excitation, followed by an energy plateau 444 where the temperature stabilizes, and finally a low temperature interval 446 when the LF power is turned off. The energy spike has a substantially static duration, meaning that no matter how quickly the LF power is pulsed, the energy spike will last for essentially the same amount of time. On the other hand, the energy plateau 444 persists for a longer or shorter period, depending on how long the LF power is on. Thus, at high pulse frequencies and low duty cycles, LF power exhibits higher average ion energies but maintains a low average ion density. Within a specific energy range, higher average ion energies increase the modulus of the hardmask, which is desirable, while lower average ion density reduces stress, which is also desirable.

[0051] In some embodiments, the duty cycle can be increased to increase the average ion density, which can result in a denser, higher modulus AHM at the expense of additional stress. AHM films deposited using higher DCs can still have higher average ion energies using the techniques disclosed herein, thereby resulting in films with better selectivity than other films with the same amount of internal stress.

[0052] The plasma also contains an inert gas, in some embodiments, helium, and is substantially free of any other gases. Heavier inert gases such as argon are often used to help contain the plasma for uniformity, however, such ions can sputter AHMs at ion energies greater than 3000 W. This is clearly undesirable for deposition processes. Helium can be used at lower ion energies without sputtering AHMs, which is desirable and results in more uniform deposition.

[0053] Processing Window

[0054] This section describes various process parameters that can be used to produce AHM films. The process parameters are provided for a plasma enhanced chemical vapor deposition process that occurs in a process chamber such as the process chamber described below.

[0055] In various embodiments, the total pressure in the process chamber is between about 0.5 Torr and about 20 Torr. In some embodiments, the pressure is between about 5 Torr and about 10 Torr, or between about 0.5 Torr and about 1.5 Torr. In some embodiments, the hydrocarbon precursor is present in the process chamber at a relatively low partial pressure (e.g., between about 0.01 Torr and about 4 Torr), such as discussed in U.S. Patent Nos. 7,981,777 and 7,981,810, which are incorporated herein by reference in their entireties. In certain embodiments, the hydrocarbon precursor partial pressure is about 0.2 Torr or less.

[0056] In some embodiments, the hydrocarbon precursor is of formula C x H y A hydrocarbon precursor as defined wherein X is an integer between 2 and 10 and Y is an integer between 2 and 24. Examples include methane (CH4), acetylene (C2H2), ethylene (C2H4), propylene (C3H6), butane (C4H 10 ), cyclohexane (C6H 12 ), benzene (C6H6), and toluene (C7H8). In certain embodiments, the hydrocarbon precursor is a halogenated hydrocarbon in which one or more hydrogen atoms are replaced by a halogen, particularly fluorine, chlorine, bromine, and / or iodine. In some embodiments, the hydrocarbon precursor comprises a compound having a molecular weight of up to about 50 g / mol. In some embodiments, the hydrocarbon precursor has a C:H ratio of at least 1:2. In some embodiments, the hydrocarbon precursor is acetylene (C2H2). In some embodiments, two or more hydrocarbon precursors may be used.

[0057] In some embodiments, the inert gas comprises at least about 50%, or at least about 80%, or at least about 95% helium by volume of the total inert gas used. In some embodiments, the inert gas is helium, substantially free of any other inert gas.

[0058] The volumetric flow rate of the precursor gas depends on the specific processing chamber, substrate, and other processing conditions. Examples of volumetric flow rates that can be used for a single 300mm substrate are acetylene between about 10 sccm and about 1000 sccm and helium between about 250 sccm and about 5000 sccm. In some embodiments, the flow rate of acetylene is between about 1% and about 3% of the total flow rate, and helium makes up the remainder of the total flow rate. In some embodiments, the volumetric flow rate is between about 15 sccm and about 45 sccm of C2H2 and between about 1455 sccm and about 1485 sccm of helium. In some embodiments, the volumetric flow rate is between about 18 sccm and about 20 sccm of C2H2 and between about 1480 sccm and about 1482 sccm of helium, all values ​​for a 300mm substrate. In some embodiments, the volumetric flow rate is between about 40 sccm and about 45 sccm of C2H2 and between about 1455 sccm and about 1460 sccm of helium. Unless otherwise specified, the flow rates disclosed herein are for a single-station tool configured for 300 mm wafers. Flow rates scale roughly linearly with the number of stations and substrate area.

[0059] The AHM film deposition methods described herein can be performed at any suitable processing temperature to obtain the desired AHM properties, such as within a range of about 50°C to about 550°C. In some embodiments, the processing temperature is between about 100°C and about 200°C. In some embodiments, the processing temperature is between about 150°C and about 175°C. The processing temperature is at least partially due to the sp 2 Key contrast sp 3 Bond formation may affect stress, selectivity, and permeability. Higher temperatures are beneficial for sp-rich 2 Amorphous carbon networks form because high temperatures facilitate the breaking of C—H bonds and enable subsequent hydrogen diffusion. For example, films deposited at temperatures above about 500° C. can have significantly more sp 2 CH and CH2 bonds, and relatively few sp 3 bonds, which have increased carbon content and higher density and are associated with increased etch selectivity. However, these sp-rich 2 films may not be suitable for thick hard mask applications. As mentioned above, the film may not be transparent enough for mask alignment. 633 nm lasers can be used for transparent and semi-transparent films, but cannot be used for less transparent films, such as films produced at high temperatures. U.S. Patent No. 7,981,810, previously incorporated herein by reference in its entirety, provides processing conditions for depositing selective and transparent AHMs at lower temperatures and / or using dilute hydrocarbon precursor flows. AHM films deposited at lower temperatures (e.g., below about 400° C.) can have less sp than films deposited at higher temperatures. 2 key.

[0060] In some embodiments, low frequency (LF) RF power refers to RF power having a frequency between about 100 kHz and about 2 MHz. In some embodiments, the pulsing frequency may be limited by the operating capabilities of the LF generator. In some embodiments, LF RF power refers to RF power having a frequency of about 400 kHz (e.g., 430 kHz). High frequency RF power refers to RF power having a frequency between about 2 MHz and about 60 MHz. In some embodiments, HF RF power refers to RF power having a frequency of about 13.56 MHz.

[0061] In some embodiments, the HF and LF RF portions can be pulsed in a synchronized manner. If the HF portion is pulsed, it is pulsed from high power to low power and not shut off to avoid plasma sheath collapse. In some embodiments, pulsing only the LF RF power can be advantageous for forming a more stable plasma.

[0062] In some embodiments, the LF power is pulsed while the HF power is constant. In various embodiments, the LF power is pulsed by switching the LF power on and off. In some embodiments, the LF "on" power is at least 3000 W per 300 mm substrate. In some embodiments, the LF "on" power is between approximately 3500 W and approximately 6500 W per 300 mm substrate. In some embodiments, the LF "off" power is 0 W. In various embodiments, the LF power is pulsed by switching the LF between non-zero power levels such that the LF off power is between 0 W and the LF on power. In some embodiments, the LF power is pulsed between approximately 1000 W and approximately 6000 W. In some embodiments, the HF power per substrate is in the range of between approximately 0 W and approximately 150 W per 300 mm substrate. In some embodiments, the HF power per substrate is in the range of between approximately 0 W and approximately 800 W. In many embodiments, the minimum power of the HF RF section and the minimum power of the LF RF section are sufficient to sustain the plasma. All powers provided herein are for 300 mm substrates. The RF power described here scales roughly linearly with the number of stations and the wafer area. Power values ​​can be expressed per area, for example, 2500W can also be expressed as 0.884W / cm 2 .

[0063] The duty cycle (DC) of the LF pulse can range from about 10% to about 90%. In some embodiments, the DC is between about 10% and about 50%, between about 10% and about 30%, or between about 10% and about 20%. In some embodiments, the DC is between about 60% and about 90%, between about 60% and about 90%, or between about 60% and about 75%. In various embodiments, the LF power is pulsed at a frequency of about 100 Hz and about 1000 Hz. In some embodiments, the LF power is pulsed at a frequency of at least about 200 Hz, or at least about 300 Hz. In some embodiments, the DC and pulse frequency are set such that the LF power on duration is between about 200 μs and about 2500 μs, and the LF power off duration is between about 800 μs and about 7500 μs. In some embodiments, the LF power has an on period lasting between about 200 μs and about 300 μs.

[0064] In some embodiments, the gap between the susceptor and the showerhead is less than about 0.75 inches (20 mm) or between about 0.25 inches (about 6 mm) and about 0.75 inches (about 20 mm). As the RF power of the plasma is increased, the gap between the susceptor and the showerhead can be increased without reducing the quality of the deposited AHM.

[0065] In some of the treatments herein, the AHM film is In some embodiments, the AHM film is deposited at a rate of about With The deposition rate of the AHM film may depend on the DC, as a longer average "on" time of the LF power will increase the deposition rate.

[0066] In some embodiments, the processing conditions for depositing the AHM film include pulsing the LF power with a duty cycle between about 10% and about 75% at at least about 3000 W per 300 mm wafer and a substantially inert gas of helium. In some embodiments, the processing conditions include pulsing the LF power with a duty cycle between about 10% and about 75% at at least 6000 W per 300 mm wafer and a substantially inert gas of helium. In some embodiments, the processing conditions include pulsing the LF power with a duty cycle between about 10% and about 40% at at least about 3000 W per 300 mm wafer and a substantially inert gas of helium.

[0067] Membrane properties

[0068] AHM films produced according to the disclosed methods are typically composed primarily of carbon and hydrogen, but other elements may also be present in the film. In general, the lower the atomic percentage of hydrogen in the mask, the higher the modulus and selectivity. In some embodiments, other elements may be added to the gas mixture. For example, if a halogenated hydrocarbon is used, the halogen may constitute a certain percentage of the film composition. In some embodiments, the hydrogen concentration is up to about 25 atomic percent. In some embodiments, the hydrogen concentration is between about 24 and 25 atomic percent. In some embodiments, the carbon concentration is at least about 70 atomic percent. In some embodiments, the carbon concentration is between about 70 and 76 atomic percent. Examples of other elements that may be present in the AHM film include halogens, nitrogen, sulfur, boron, oxygen, tungsten, titanium, and aluminum. Typically, such other elements are present in an amount not greater than 10 atomic percent.

[0069] In some embodiments, the AHM films produced according to the methods described herein have an internal stress magnitude of at most about -1400 MPa, or between about -200 MPa and about -1400 MPa (negative internal stress indicates compressive stress, such that lower values ​​have less internal stress). In some embodiments, the AHM films have an elastic modulus of at least about 80 GPa, or between about 145 GPa and 160 GPa. In some embodiments, the AHM films have a hardness of at least about 9 GPa, or between about 15 GPa and about 17 GPa. In some embodiments, the AHM films have a hardness of at least about 1.5 g / cm 3 , or between about 1.8g / cm 3 and about 1.9g / cm 3The density between.

[0070] In some embodiments, the AHM film produced according to the methods described herein has an extinction coefficient of at most about 0.4 at 633 nm. The extinction coefficient can be correlated with the ability of light to move through the AHM film, or the permeability of the film. In some embodiments, the AHM film is transparent or translucent. AHM films that do not have a sufficiently low extinction coefficient value may require additional steps in subsequent etching processes to etch the AHM film, which is undesirable.

[0071] In some embodiments, the thickness of the AHM film deposited according to the methods described herein is between about 100 nm and about 2500 nm. Generally speaking, the desired AHM film thickness may vary depending on the thickness of the underlying layer to be etched and the etch selectivity of the AHM, with thicker underlying layers requiring thicker AHMs. As discussed above, AHM films are used to etch a variety of underlying materials and may have different etch selectivities for each material. The etch selectivity of an AHM can be expressed as the ratio of the etch rate of a material to the etch rate of the AHM and may vary for different materials and etch chemistries.

[0072] application

[0073] AHM is typically used to create features of semiconductor devices by etching one or more underlying layers of a substrate. Materials that can be etched using an AHM can include silicon (single crystal, polycrystalline, or amorphous silicon), silicon oxide, silicon nitride, and tungsten. In some embodiments, multiple layers are stacked and etched using a single AHM. Examples of such stacks include a silicon layer and a silicon oxide layer, and a tungsten layer and a silicon nitride layer. In some embodiments, the stack includes repeating layers that are etched using a single AHM. Examples of such repeating layers include repeating layers of silicon oxide / polycrystalline silicon (OPOP). Features at the front end of the line and the back end of the line can be etched using the AHM disclosed herein. Features of memory or logic devices can be patterned. Examples of memory devices include: DRAM, NAND, and 3D NAND.

[0074] Example

[0075] Figure 5 and 6 The effect of LF power on the refractive index of AHMs under pulsed or continuous wave conditions is shown. The refractive index (or RI) can generally be used as a proxy for the selectivity of a material, with a higher refractive index indicating a higher selectivity of the AHM. The continuous wave power is where the LF power is maintained relatively constant during deposition.

[0076] Figure 5is a graph of refractive index as a function of LF power. Line 504 represents measurements from an AHM deposited using continuous wave (CW) LF power, while line 502 represents measurements from an AHM deposited by pulsing the LF power as described herein. Figure 5 The figure shows that the refractive index, and therefore the selectivity, of an AHM deposited using a continuous wave technique decreases as the power increases. Conversely, as the power of the pulsed LF power increases, the refractive index or selectivity of the AHM increases. Therefore, as the LF power increases, a continuous wave technique will result in a less selective AHM, while a pulsed technique will result in a more selective AHM.

[0077] Figure 6 is a graph of refractive index as a function of internal stress, where negative stress is compressive stress, and a more neutral stress is desirable. Line 606 is a plot of refractive index as a function of stress for some AHMs, showing that internal stress generally increases as refractive index or selectivity increases. For continuous wave power, line 604 shows that as LF power increases, refractive index decreases while internal compressive stress increases. Both are undesirable, indicating that lower LF power is desirable for continuous wave technology. Conversely, line 602 shows that for pulsed LF power, both refractive index and stress increase as LF power increases. However, line 602 is steeper than line 606, indicating that as pulsed LF power increases, the refractive index increases at a higher rate relative to internal stress than line 606. Therefore, while increasing LF power increases stress, this increase in stress is offset by a larger-than-usual increase in selectivity.

[0078] The following table presents various film properties for two different films deposited according to some embodiments disclosed herein. The 3625W process deposited an AHM film by pulsing the LF power between 0W and 3625W while exposing the substrate to a process gas of 44 sccm of C2H2 and 1466 sccm of helium. The 6000W process deposited an AHM film by pulsing the LF power between 0W and 6000W while exposing the substrate to a process gas of 18 sccm of C2H2 and 1482 sccm of helium. Range %NU is a measure of deposition non-uniformity. H% is the percentage of hydrogen in the AHM measured using hydrogen forward scattering. XRR density is the density measured by X-ray reflectivity.

[0079]

[0080] Device

[0081] Embodiments may be implemented in a plasma enhanced chemical vapor deposition (PECVD) reactor. Such a reactor may take many different forms. Various embodiments are compatible with existing semiconductor processing equipment, particularly Sequel, available from Lam Research Corporation. TM or Vector TM The various embodiments can be implemented on multi-station or single-station tools. In a specific embodiment, a 300mm Lam Vector with a 4-station deposition scheme is used. TM tool or 200mm Sequel with 6-station deposition solution TM tool.

[0082] Generally speaking, the apparatus will include one or more chambers or reactors, each containing one or more stations. The chamber will house one or more wafers and be suitable for wafer processing. The one or more chambers maintain the wafers in one or more defined positions by preventing rotation, vibration, or other disturbances. In some embodiments, wafers undergoing AHM deposition are transferred from one station to another within the chamber during processing. For example, AHM deposition can occur entirely at one station, or, according to various embodiments, can be deposited at each of the four stations. Alternatively, any other portion of the total film thickness can be deposited at any number of stations. In various embodiments where more than one AHM is deposited, more than one station can be used to deposit each AHM layer. During processing, each wafer is held in place by a susceptor, wafer chuck, and / or other wafer holding device. For some operations where the wafer is heated, the device may include a heater such as a hot plate.

[0083] Figure 7 Schematically illustrates an embodiment of a process station 700 that can be used to deposit materials using plasma enhanced chemical vapor deposition (PECVD). For simplicity, the process station 700 is depicted as a standalone process station having a process chamber body 702 for maintaining a low pressure environment. However, it should be understood that multiple process stations 700 can be included in a common process tool environment. Furthermore, it should be understood that in some embodiments, one or more hardware parameters of the process station 700, including those discussed in detail below, can be programmatically adjusted by one or more computer controllers.

[0084] The processing station 700 is in fluid communication with a reactant delivery system 701 for delivering process gases to a distribution showerhead 706. The reactant delivery system 701 includes a mixing vessel 704 for blending and / or conditioning process gases for delivery to the showerhead 706. One or more mixing vessel inlet valves 720 can control the introduction of process gases into the mixing vessel 704. Similarly, a showerhead inlet valve 705 can control the introduction of process gases into the showerhead 706.

[0085] For example, Figure 7 The embodiment includes a vaporization point 703, which is used to vaporize liquid reactants to be supplied to the mixing container 704. In some embodiments, the vaporization point 703 can be a heated evaporator. The reactant vapors produced from such an evaporator will condense in the downstream delivery pipe. Incompatible gases exposed to the condensed reactants will produce small particles. These small particles may block the pipes, hinder valve operation, contaminate the substrate, etc. Some methods for dealing with these problems involve cleaning and / or evacuating the delivery pipes to remove residual reactants. However, cleaning the delivery pipes will increase the processing station cycle time and reduce the processing station throughput. Therefore, in some embodiments, the delivery pipes downstream of the vaporization point 703 can be heat traced. In some examples, the mixing container 704 can also be heat traced. In a non-limiting example, the pipes downstream of the vaporization point 703 have an elevated temperature profile that rises from about 100°C to about 150°C at the mixing container 704.

[0086] In some embodiments, the reactant liquid can be vaporized at the liquid ejector. For example, the liquid ejector can eject a pulse of liquid reactant into the carrier gas flow upstream of the mixing vessel. In one case, the liquid ejector can vaporize the reactant by flashing the liquid from a higher pressure to a lower pressure. In another case, the liquid ejector can atomize the liquid into dispersed droplets that are then vaporized in a heated delivery pipe. It should be understood that smaller droplets can vaporize faster than larger droplets, thereby reducing the delay between liquid injection and completion of vaporization. Faster vaporization can reduce the length of the pipeline downstream of the vaporization point 703. In one case, the liquid ejector can be directly loaded into the mixing vessel 704. In another case, the liquid ejector can be directly loaded into the spray head 706.

[0087] In some embodiments, a liquid flow controller can be set upstream of the vaporization point 703 to control the mass flow of the liquid for vaporization and delivery to the processing station 700. For example, a liquid flow controller (LFC) can include a thermal mass flow meter (MFM) located downstream of the LFC. The plunger valve of the LFC can then be adjusted in response to a feedback control signal provided by a proportional integral differential (PID) controller in electrical communication with the MFM. However, it can take one second or longer to use feedback control to stabilize the liquid flow. This can extend the time of dosing the liquid reactant. Therefore, in some embodiments, the LFC can dynamically switch between a feedback control mode and a direct control mode. In some embodiments, the LFC can dynamically switch from the feedback control mode to the direct control mode by disabling the sensing conduit and PID controller of the LFC.

[0088] Showerhead 706 distributes process gas toward substrate 712. Figure 7 In the illustrated embodiment, substrate 712 is positioned below showerhead 706 and is shown resting on pedestal 708. It will be appreciated that showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports to distribute process gases to substrate 712.

[0089] In some embodiments, the microvolume 707 is located below the showerhead 706. Performing ALD and / or CVD processing in a microvolume rather than in the entire volume of the processing station can reduce reactant exposure and purge time, can reduce the time to change processing conditions (e.g., pressure, temperature, etc.), can limit the exposure of the processing station robot to process gases, etc. Exemplary microvolume sizes include, but are not limited to, volumes between 0.1 liters and 2 liters. This microvolume also affects productivity throughput. When the deposition rate per cycle decreases, the cycle time is also reduced. In some cases, for a given target film thickness, the effect of the cycle time reduction is significant enough to increase the overall yield of the module.

[0090] In some embodiments, the pedestal 708 can be raised or lowered to expose the substrate 712 to the microvolume 707 and / or to change the volume of the microvolume 707. For example, during a substrate transfer phase, the pedestal 708 can be lowered to enable the substrate 712 to be loaded onto the pedestal 708. During a deposition process phase, the pedestal 708 can be raised to position the substrate 712 within the microvolume 707. In some embodiments, the microvolume 707 can completely surround the substrate 712 and a portion of the pedestal 708 to form a region of high flow impedance during the deposition process.

[0091] Optionally, the pedestal 708 can be lowered and / or raised during portions of the deposition process to adjust the process pressure, reactant concentration, etc. within the microvolume 707. Lowering the pedestal 708 can allow the microvolume 707 to be evacuated, while maintaining the process chamber body 702 at a base pressure during the deposition process. Exemplary ratios of the microvolume to the process chamber volume include, but are not limited to, volume ratios between 1:700 and 1:10. It should be understood that in some embodiments, the pedestal height can be programmatically adjusted by a suitable computer controller.

[0092] In another embodiment, adjusting the height of the pedestal 708 can allow for varying plasma density during plasma startup and / or processing cycles included in a deposition process. At the end of a deposition process phase, the pedestal 708 can be lowered during another substrate transfer phase to enable removal of the substrate 712 from the pedestal 708.

[0093] Although the exemplary microvolume variations described herein relate to a height-adjustable pedestal, it should be understood that in some embodiments, the position of the showerhead 706 can be adjusted relative to the pedestal 708 to change the volume of the microvolume 707. Furthermore, it should be understood that the vertical position of the pedestal 708 and / or showerhead 706 can be changed by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 708 can include a rotation axis for rotating the orientation of the substrate 712. It should be understood that in some embodiments, one or more of these exemplary adjustments can be performed programmatically by one or more appropriate computer controllers.

[0094] Back to Figure 7In the illustrated embodiment, the showerhead 706 and the base 708 are in electrical communication with an RF power source 714 and a matching network 716 for powering the plasma. In some embodiments, the energy of the plasma can be controlled by controlling one or more of the pressure of the processing station, the concentration of the gas, the RF source power, the RF source frequency, and the timing of the plasma power pulses. For example, the RF power source 714 and the matching network 716 can be operated at any suitable power to form a plasma having a desired composition of free radical species. Examples of suitable powers are included above. Similarly, the RF power source 714 can provide RF power of any appropriate frequency. In some embodiments, the RF power source 714 can be configured to control a high-frequency RF power source and a low-frequency RF power source independently of each other. Exemplary low-frequency RF frequencies may include, but are not limited to, frequencies between 50 kHz and 700 kHz. Exemplary high-frequency RF frequencies may include, but are not limited to, frequencies between 1.8 MHz and 2.45 GHz. It should be understood that any suitable parameters can be adjusted discretely or continuously to provide plasma energy for surface reactions. In one non-limiting example, the plasma power may be intermittently pulsed to reduce ion bombardment of the substrate surface, as opposed to a continuously powered plasma.

[0095] In some embodiments, the plasma can be monitored in situ by one or more plasma monitors. In one case, the plasma power can be monitored by one or more voltage and current sensors (e.g., VI probes). In another case, the plasma density and / or the concentration of the process gas can be measured by one or more optical emission spectroscopy sensors (OES). In some embodiments, one or more plasma parameters can be adjusted programmatically based on the measurement results from such in situ plasma monitors. For example, an OES sensor can be used in a feedback loop to provide programmable control of the plasma power. It should be understood that in some embodiments, other monitors can be used to monitor the plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure sensors.

[0096] In some embodiments, the plasma can be controlled via input / output control (IOC) sequencing instructions. In one example, instructions for setting the plasma conditions for a plasma treatment phase can be included in a corresponding plasma activation recipe phase of a deposition process recipe. In some cases, the process recipe phases can be arranged in sequence so that all instructions for a deposition process phase are executed simultaneously with that process phase. In some embodiments, instructions for setting one or more plasma parameters can be included in a recipe phase preceding the plasma treatment phase. For example, a first recipe phase can include instructions for setting the flow rate of an inert gas and / or a hydrocarbon precursor gas, instructions for setting a plasma generator to a power set point, and time delay instructions for the first recipe phase. A subsequent second recipe phase can include instructions for enabling the plasma generator and time delay instructions for a second recipe phase. A third recipe phase can include instructions for disabling the plasma generator and time delay instructions for the third recipe phase. It should be understood that these recipe phases can be further subdivided and / or iterated in any suitable manner within the scope of the present disclosure.

[0097] In some embodiments, the susceptor 708 can be temperature controlled by a heater 710. Additionally, in some embodiments, pressure control of the deposition processing station 700 can be provided by a butterfly valve 718. Figure 7 In the embodiment shown, butterfly valve 718 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, the pressure control of the process station 700 can also be adjusted by changing the flow rate of one or more gases introduced into the process station 700.

[0098] Figure 8 Shown is a schematic diagram of an embodiment of a multi-station processing tool 800, which has an inbound load lock 802 and an outbound load lock 804, one of which or both may include a remote plasma source. Under atmospheric pressure, a robot 806 is configured to move a wafer from a box loaded by a wafer boat 808 into the inbound load lock 802 via an atmospheric port 810. The wafer is placed on a pedestal 812 in the inbound load lock 802 by the robot 806, the atmospheric port 810 is closed, and the load lock is evacuated. When the inbound load lock 802 includes a remote plasma source, the wafer can be exposed to the remote plasma treatment in the load lock before being introduced into a processing chamber 814. In addition, the wafer can also be heated in the inbound load lock 802, for example, to remove moisture and adsorbed gas. Next, a chamber transfer port 816 leading to the processing chamber 814 is opened, and another robot (not shown) places the wafer into the reactor on the pedestal of the first station shown in the reactor for processing. While the embodiment shown in FIG. 4 includes a load lock, it will be appreciated that in some embodiments, wafers may be made to enter the processing station directly.

[0099] The depicted processing chamber 814 contains four processing stations, Figure 8 In the embodiment shown, the stations are numbered 1 to 4. Each station has a heated susceptor (shown as 818 for station 1) and a gas line inlet. It should be understood that in some embodiments, each processing station can have different or multiple uses. Although the process chamber 814 is depicted as including four stations, it should be understood that a process chamber according to the present disclosure can have any suitable number of stations. For example, in some embodiments, a process chamber can have five or more stations, while in other embodiments, a process chamber can have three or fewer stations.

[0100] Figure 8 Also depicted is an embodiment of a wafer handling system 890 for transporting wafers within the processing chamber 814. In some embodiments, the wafer handling system 890 can transport wafers between various processing stations and / or between a processing station and a load lock. It should be understood that any suitable wafer handling system can be employed. Non-limiting examples include a wafer turntable and a robot for handling wafers. Figure 8 Also depicted is an embodiment of a system controller 850 for controlling the processing conditions and hardware states of the processing tool 800. The system controller 850 may include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. The processor 852 may include a CPU or computer, analog and / or digital input / output connections, a stepper motor controller board, etc.

[0101] In some embodiments, a system controller 850 controls all activities of the process tool 800. The system controller 850 executes system control software 858 stored on a mass storage device 854, loaded into a memory device 856, and executed on a processor 852. The system control software 858 may include instructions for controlling timing, gas mixing, chamber and / or station pressures, chamber and / or station temperatures, purge conditions and timing, wafer temperature, RF power levels, RF frequencies, substrate, susceptor, chuck and / or susceptor positions, and other parameters of a particular process performed by the process tool 800. The system control software 858 may be configured in any suitable manner. For example, various process tool component subroutines or control objects may be written to control the operation of the process tool components necessary to perform various process tool processes according to the disclosed methods. The system control software 858 may be coded in any suitable computer-readable programming language. In some embodiments, the system control software 858 may include input / output control (IOC) sequencing instructions for controlling the various parameters described above.

[0102] In some embodiments, other computer software and / or programs stored on the mass storage device 854 and / or the memory device 856 associated with the system controller 850 may be employed. Examples of programs or program segments used for this purpose include substrate positioning programs, process gas control programs, pressure control programs, heater control programs, and plasma control programs.

[0103] The substrate positioning program may contain program code for processing tool components that are used to load a substrate onto the pedestal 818 and control the spacing between the substrate and other parts of the processing tool 800.

[0104] The process gas control program may include code for controlling gas composition and flow rate and, optionally, for flowing gas into one or more process stations prior to deposition to stabilize the pressure in the process station. The process gas control program may include code for controlling gas composition and flow rate within any disclosed range. The pressure control program may include code for controlling the pressure within the process station by adjusting, for example, a throttle valve in the exhaust system of the process station, gas flow into the process station, and the like. The pressure control program may include code for maintaining the pressure in the process station within any disclosed pressure range.

[0105] The heater control program may include code for controlling the flow of current to a heating unit that is used to heat the substrate. Alternatively, the heater control program may control the delivery of a heat transfer gas (e.g., helium) to the substrate. The heater control program may include instructions for maintaining the temperature of the substrate within any of the disclosed ranges.

[0106] The plasma control program may include code for setting the RF power level and frequency applied to the processing electrodes in one or more processing stations, for example using any of the RF power levels disclosed herein. The plasma control program may also include code for controlling the duration of each plasma exposure.

[0107] In some embodiments, there may be a user interface associated with the system controller 850. The user interface may include a display screen, graphical software displays of apparatus and / or processing conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, and the like.

[0108] In some embodiments, the parameters regulated by the system controller 850 relate to process conditions. Non-limiting examples include process gas composition and flow rate, temperature, pressure, plasma conditions (e.g., RF power level, frequency, and exposure time), etc. These parameters can be provided to the user in the form of a recipe, which can be entered using the user interface.

[0109] Signals for monitoring the process can be provided from various process tool sensors via analog and / or digital input connections of the system controller 850. Signals for controlling the process can be output via analog and / or digital output connections of the process tool 800. Non-limiting examples of process tool sensors that can be monitored include mass flow controllers, pressure sensors (e.g., manometers), thermocouples, and the like. Appropriately programmed feedback and control algorithms can be used with the data from these sensors to maintain process conditions.

[0110] Any suitable chamber may be used to implement the disclosed embodiments. Exemplary deposition equipment includes, but is not limited to, Product Series, product line and / or product line, or any of a variety of other commercially available processing systems, wherein The product line is available from Lam Research Corp. of Fremont, California. Two or more stations can perform the same function. Similarly, two or more stations can perform different functions. Each station can be designed / configured to perform a specific function / method as needed.

[0111] Figure 9 is a block diagram of a processing system suitable for performing thin film deposition processing according to certain embodiments. System 900 includes a transport module 903. The transport module 903 provides a clean, pressurized environment to minimize the risk of contamination when the substrate being processed moves between the various reactor modules. According to certain embodiments, mounted on the transport module 903 are two multi-station reactors 909 and 910, each reactor capable of performing atomic layer deposition (ALD) and / or chemical vapor deposition (CVD). Reactors 909 and 910 may include a plurality of stations 911, 913, 915 and 917, which may perform operations sequentially or non-sequentially according to the disclosed embodiments. These stations may include a heated susceptor or substrate support, one or more gas inlets or nozzles or a dispersion plate.

[0112] Mounted on the transfer module 903 may also be one or more single-station or multi-station modules 907 capable of performing plasma or chemical (non-plasma) pre-cleaning, or any other process associated with the disclosed method. In some cases, the module 907 may be used for a variety of processes, such as preparing a substrate for a deposition process. The module 907 may also be designed / configured to perform a variety of other processes, such as etching or polishing. The system 900 also includes one or more wafer source modules 901, in which wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 919 may first move the wafer from the source module 901 to the load lock 921. The wafer transfer device (typically a robotic arm unit) in the transfer module 903 moves the wafer from the load lock 921 to the modules mounted on the transfer module 903 and to the modules mounted on the transfer module 903.

[0113] In various embodiments, a system controller 929 is used to control process conditions during the deposition process. The controller 929 will typically include one or more memory devices and one or more processors. The processor may include a CPU or calculator, analog and / or digital input / output connections, a stepper motor controller board, and the like.

[0114] The controller 929 controls all of the activities of the deposition apparatus. The system controller 929 executes system control software, which includes a set of instructions for controlling timing, gas mixtures, chamber pressure, room temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or susceptor position, and other parameters specific to the process. Other computer programs stored in a memory device associated with the controller 929 may be employed in some embodiments.

[0115] There will typically be a user interface associated with the controller 929. The user interface may include a display screen, a graphical software display of the apparatus and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, and the like.

[0116] The system control logic can be configured in any suitable manner. Generally speaking, the logic can be designed or configured in hardware and / or software. The instructions for controlling the driver circuit can be hard-coded or provided as software. The instructions can be provided through "programming." Such programming is understood to include any form of logic, including hard-coded logic in digital signal processors, application-specific integrated circuits, and other devices with specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions that can be executed on a general-purpose processor. The system control software can be encoded in any suitable computer-readable programming language.

[0117] The computer program code for controlling the pulses of the germanium-containing reducing agent, the flow of hydrogen, and the pulses of the tungsten-containing precursor, as well as other processes in the process sequence, can be written in any commonly used computer-readable programming language, such as assembly language, C, C++, Pascal, Fortran, or others. The compiled object code or script is executed by a processor to perform the tasks identified in the program. Also as indicated, the program code can be hard-coded.

[0118] Controller parameters relate to process conditions such as, for example, process gas composition and flow rate, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of recipes and can be input using the user interface. Signals for monitoring the process can be provided via analog and / or digital input connections of the system controller 929. Signals for controlling the process are output via analog and digital output connections of the deposition apparatus.

[0119] The system software can be designed or configured in many different ways. For example, in accordance with the disclosed embodiments, various chamber component subroutines or control objects can be written to control the operation of the chamber components necessary to perform deposition processes (and in some cases other processes). Examples of programs or program segments for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0120] In some implementations, the controller 929 is part of a system that can be part of the above-described embodiments. Such a system can include semiconductor processing equipment that includes one or more processing tools, one or more processing chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems can be integrated with electronics that control their operation before, during, and after processing semiconductor wafers or substrates. The electronics can be referred to as a "controller," which can control various components or subcomponents of one or more systems. Depending on the processing requirements and / or the type of system, the controller 929 can be programmed to control any of the processes disclosed herein, including controlling process gas delivery, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, wafer transfer in and out of tools and other transfer tools, and / or load locks connected to or interfaced with a specific system.

[0121] In a broad sense, a controller can be defined as an electronic device having various integrated circuits, logic, memory and / or software that receives instructions, issues instructions, controls operations, enables cleaning operations, enables endpoint measurements, and the like. The integrated circuit can include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). The program instructions can be instructions transmitted to the controller in the form of various separate settings (or program files) that define operating parameters for performing specific processing on or for a semiconductor wafer or system. In some embodiments, the operating parameters can be part of a recipe defined by a process engineer for completing one or more processing steps during the preparation of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0122] In some implementations, the controller can be part of or coupled to a computer that is integrated with, coupled to, or connected to the system via a network, or a combination thereof. For example, the controller can be in the "cloud" or all or part of a wafer fab host system, thereby allowing remote access to wafer processing. The computer can enable remote access to the system to monitor the current progress of manufacturing operations, review the history of past manufacturing operations, review trends or performance metrics across multiple manufacturing operations, change parameters of a current process, set process steps to follow the current process, or start a new process. In some embodiments, a remote computer (e.g., a server) can provide process recipes to the system via a network, which can include a local network or the Internet. The remote computer can include a user interface that allows for the input or programming of parameters and / or settings, which are then transmitted from the remote computer to the system. In some embodiments, the controller receives instructions in the form of data that specify parameters for each process step to be performed during one or more operations. It should be understood that the parameters can be specific to the type of process to be performed and the type of tool the controller is configured to connect to or control. Thus, as described above, the controller can be distributed, for example, by including one or more discrete controllers that are connected together via a network and work toward a common goal (e.g., processing and control as described herein). An embodiment of a distributed controller for these purposes can be one or more integrated circuits on the chamber that communicate with one or more remote integrated circuits (e.g., at the platform level or as part of a remote computer) that are combined to control the processing within the chamber.

[0123] Example systems may include, but are not limited to, plasma etch chambers or modules, deposition chambers or modules, spin cleaning chambers or modules, metal plating chambers or modules, cleaning chambers or modules, bevel edge etch chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etch (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing system that may be associated with or used in the preparation and / or manufacture of semiconductor wafers.

[0124] As described above, depending on the one or more processing steps to be performed by the tool, the controller can communicate with one or more of the following: other tool circuits or modules, other tool components, combination tools, other tool interfaces, adjacent tools, adjacent tools, tools located throughout the factory, a host computer, another controller, or tools used in material handling to move containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing facility.

[0125] in conclusion

[0126] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be implemented within the scope of the appended claims. It should be noted that there are many alternative ways of implementing the processes, systems, and devices of the embodiments herein. In other cases, well-known processing operations are not described in detail so as not to unnecessarily obscure the disclosed embodiments. Therefore, the embodiments herein are to be considered as illustrative and non-restrictive, and the embodiments should not be limited to the details set forth herein.

Claims

1. A method of forming an ashable hard mask (AHM) film, comprising: exposing the semiconductor substrate to a process gas comprising a hydrocarbon precursor gas and helium without any other inert gas; and Depositing an AHM film on the semiconductor substrate by a plasma enhanced chemical vapor deposition (PECVD) process, wherein the process comprises: Ignite a plasma generated by a dual radio frequency (RF) plasma source comprising a high frequency (HF) section and a low frequency (LF) section, The power of the HF part is constant during deposition, and The power of the LF section is pulsed at between 3500W and 6500W per 300mm wafer and at a duty cycle between 10% and 75%. 2 . The method of claim 1 , wherein the hydrocarbon precursor gas comprises compounds having a molecular weight of at most 50 g / mol.

3. The method of claim 1, wherein the hydrocarbon precursor gas comprises a compound having a C:H ratio of at least 0.

5.

4. The method of claim 1, wherein the hydrocarbon precursor gas comprises acetylene (C2H2).

5. The method of claim 1, wherein the hydrocarbon precursor gas has a partial pressure between 1-2% of the process gas. The method of claim 1 , wherein the LF power is provided at a frequency less than or equal to 2 MHz. The method of claim 1 , wherein the LF power is pulsed at a frequency of at least 100 Hz. The method of claim 1 , wherein the LF power is pulsed at a frequency between 100 Hz and 1000 Hz.

9. The method of claim 1, wherein the duty cycle of the LF power is between 10% and 50%.

10. The method of claim 1, wherein the duty cycle of the LF power is between 60% and 75%. The method of claim 1 , wherein the LF power has an on-time period with a duration between 200 microseconds and 300 microseconds.

12. The method of claim 1, wherein the method is performed in a multi-station reactor.

13. The method according to any one of claims 1 to 12, wherein the internal stress of the AHM film is at most 1400 MPa.

14. The method of any one of claims 1 to 12, wherein the AHM film has a modulus of at least 80 GPa.

15. The method of any one of claims 1 to 12, wherein the AHM film has a density of at least 1.5 g / cm 3 .

16. The method of any one of claims 1 to 12, wherein the AHM film has a hydrogen concentration of at most 25 atomic %.

17. The method of any one of claims 1 to 12, wherein the thickness of the AHM film is at most 2500 nm.

18. The method of any one of claims 1 to 12, wherein the method is performed in a processing chamber having a susceptor and a showerhead, and a gap between the susceptor and the showerhead is less than 20 mm.

19. The method of any one of claims 1 to 12, further comprising patterning the AHM film and etching the patterned AHM film to define features of the AHM film in the substrate.

20. The method of claim 19, further comprising etching a layer of the substrate below the AHM film.

21. A method of forming an ashable hard mask (AHM) film, comprising: exposing the semiconductor substrate to a process gas comprising a hydrocarbon precursor gas and an inert gas; and Depositing an AHM film on the semiconductor substrate by a plasma enhanced chemical vapor deposition (PECVD) process, wherein the process comprises: Ignite a plasma generated by a dual radio frequency (RF) plasma source comprising a high frequency (HF) section and a low frequency (LF) section, The power of the HF part is constant during deposition, and The power of the LF section is pulsed between 3500W and 6500W per 300mm wafer with the LF power on time being less than 300 microseconds per duty cycle.

22. The method of claim 21, wherein the duty cycle of the LF power is between 10% and 50%.

23. The method of claim 21, wherein the LF power on time is between 200 microseconds and 300 microseconds.

24. The method of claim 21, wherein the LF power is pulsed at a frequency of at least 100 Hz.

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