Systems and methods for depositing high density and high tensile stress films

Abstract

An exemplary method of semiconductor processing may include flowing a silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen into a processing region of a semiconductor processing chamber. A substrate may be housed within a processing region of a semiconductor processing chamber. The method may also include forming a plasma of a silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen. The plasma may be formed at a frequency above 15 MHz. The method may also include depositing a silicon nitride material on the substrate.

Description

[0001] This application is a divisional application of the application patent application with the application number “202180070005.X” and the title “SYSTEMS AND METHODS FOR DEPOSITING HIGH DENSITY AND HIGH TENSILE STRESS FILMS” filed on August 26, 2021, having an application date of August 26, 2021.

[0002] Cross Reference to Related Applications

[0003] This application claims the benefit of and priority to U.S. Patent Application No. 17 / 009,002, filed September 1, 2020, entitled “SYSTEMS AND METHODS FOR DEPOSITING HIGH DENSITY AND HIGH TENSILE STRESS FILMS,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0004] The present technology relates to deposition processes and chambers. More specifically, the present technology relates to methods of producing high density and high tensile stress films at low temperatures. BACKGROUND

[0005] Processes that produce complex patterned layers of material on a substrate surface enable integrated circuits. Producing patterned material on a substrate requires controlled methods of forming and removing material. Plasma enhanced deposition can produce films with certain properties that can affect the performance of a device. The properties of the film can be adjusted or enhanced by modifying deposition conditions, such as the chemical composition and frequency of the plasma.

[0006] Accordingly, there is a need for improved systems and methods that can be used to produce high quality devices and structures. The present technology addresses these and other needs. SUMMARY

[0007] An example method of semiconductor processing can include flowing a silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen into a processing region of a semiconductor processing chamber. A substrate can be received within the processing region of the semiconductor processing chamber. The method can also include forming a plasma of the silicon-containing precursor, the nitrogen-containing precursor, and the diatomic hydrogen. The plasma can be formed at a frequency above 15 MHz. The method can also include depositing a silicon nitride material on the substrate.

[0008] In some embodiments, the silicon nitride material can be characterized by a density higher than or about 2.85 g / cm 3 The silicon nitride material can be characterized by a stress higher than or about 400 MPa. The silicon nitride material can be characterized by a refractive index higher than or about 1.75. The silicon nitride material can include less than or about 10% hydrogen.

[0009] More than or about 100 seem of diatomic hydrogen can flow into a processing region of a semiconductor processing chamber. Less than or about 5000 seem of diatomic hydrogen can flow into the processing region of the semiconductor processing chamber.

[0010] The plasma can be formed at a temperature of less than or about 550 °C. The frequency can be more than or about 27 MHz.

[0011] Some embodiments can encompass a method comprising flowing a silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen into a processing region of a semiconductor processing chamber. A substrate can be housed within the processing region of the semiconductor processing chamber. The method can further comprise forming a plasma of the silicon-containing precursor, the nitrogen-containing precursor, and the diatomic hydrogen, wherein the plasma is free of any material having a nitrogen-hydrogen bond. Further, the method can further comprise depositing a silicon nitride material on the substrate. The silicon nitride material can be characterized by a density of more than or about 2.85 g / cm 3 The silicon nitride material can be characterized by a stress of more than or about 400 MPa.

[0012] In some embodiments, the silicon nitride material can be characterized by a refractive index of more than or about 1.75. The silicon nitride material can comprise less than or about 10% hydrogen.

[0013] More than or about 100 seem of diatomic hydrogen can flow into a processing region of a semiconductor processing chamber. Less than or about 5000 seem of diatomic hydrogen can flow into the processing region of the semiconductor processing chamber.

[0014] The plasma can be formed at a temperature of less than or about 550 °C. The plasma can be formed at a frequency of 15 MHz or more. The frequency can be more than or about 27 MHz.

[0015] Some embodiments of the present technology can encompass a method comprising flowing a silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen into a processing region of a semiconductor processing chamber. A substrate can be housed within the processing region of the semiconductor processing chamber. The method can further comprise forming a plasma of the silicon-containing precursor, the nitrogen-containing precursor, and the diatomic hydrogen. Further, the method can further comprise depositing a silicon nitride material on the substrate. More than or about 100 seem of diatomic hydrogen can flow into the processing region of the semiconductor processing chamber, and less than or about 5000 seem of diatomic hydrogen can flow into the processing region of the semiconductor processing chamber.

[0016] In some embodiments, the silicon nitride material can be characterized by a density of more than or about 2.85 g / cm 3 The silicon nitride material can be characterized by a stress of more than or about 400 MPa.

[0017] Such techniques can provide numerous benefits over conventional systems and techniques. For example, including diatomic hydrogen with silicon-containing and nitrogen-containing precursors during high frequency plasma deposition can provide silicon nitride films with improved properties. For example, both the density and stress of the silicon nitride films can be improved. In addition, the hydrogen incorporation in the silicon nitride films can be reduced. Further, the silicon nitride films can be formed at low temperatures, thereby reducing thermal budgets and preventing damage to other layers. These and other embodiments, as well as many of their advantages and features, will be described in more detail in conjunction with the following description and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] A further understanding of the nature and advantages of the disclosed technology can be realized by reference to the remaining portions of the specification and the drawings.

[0019] Figure 1 A top plan view of an exemplary processing system is shown in accordance with some embodiments of the present technology.

[0020] Figure 2 A schematic cross-sectional view of an exemplary plasma system is shown in accordance with some embodiments of the present technology.

[0021] Figure 3 Operations of an exemplary method of semiconductor processing are shown in accordance with some embodiments of the present technology.

[0022] Figures 4A-4D Examples of growth mechanisms in some deposition processes are illustrated.

[0023] Figures 4E-4G Examples of growth mechanisms in accordance with some embodiments of the present technology are illustrated.

[0024] Figures 5A-5F Various deposition and film parameters as a function of flow rate of diatomic hydrogen in accordance with some embodiments of the present technology are illustrated.

[0025] Several of the figures are included as schematic representations of idealized embodiments of specific embodiments of the technology. It will be understood that in the drawings, identical or similar components that are shown throughout the figures can be indicated by like reference numerals. Furthermore, various components of the embodiments can be indicated herein in singular form or in plural form, according to the number of such components present in the figures. However, it will be understood that when described and / or claimed in plural form, such components should be interpreted as being indivisible from the other aforementioned components, unless otherwise indicated. Moreover, it will be understood that, although the drawings can provide showings of idealized embodiments of the technology, aspects such as materials dimensions, locations, orientations, etc. of the figures are not necessarily drawn to scale unless specifically indicated.

[0026] In the drawings, like components and / or features can have the same reference label. Also, various components of the embodiments can be identified hereinafter with a first reference numeral followed by a lower case letter to indicate one of multiple instances of the components. Unless otherwise indicated, the described and / or claimed embodiments can use one or both of the components and / or features regardless of the reference label(s) used with the components and / or features. DETAILED DESCRIPTION

[0027] Plasma enhanced deposition processes can excite one or more constituent precursors to facilitate film formation on a substrate. Any number of material films can be produced to create semiconductor structures, including conductive and dielectric films, as well as films that facilitate material transfer and removal. For example, in memory production such as DRAM, deposition of films can be performed to create cell structures. To reduce thermal budgets and prevent damage to already deposited material, it is desirable to use low temperature deposition processes. For example, temperatures during deposition of films can be less than or about 550 °C, less than or about 450 °C, or even lower.

[0028] Silicon nitride films can be used as hard masks, in which case high density, high tensile stress, and high quality can improve processing of certain structures being produced. High density films can be more resistant to more etching chemistries and can have higher etch selectivity with respect to materials above or below the film to form various patterns. Because silicon nitride films that can typically be formed on a wafer are characterized by compressive stress due to features of the structure and materials used when formed, silicon nitride films characterized by tensile stress can produce more neutral stress or flat curvature, which can prevent cracking, delamination, or other processing effects. However, many conventional low temperature deposition processes have a tradeoff between density and stress of silicon nitride films, so it is not possible to achieve high density and high tensile stress at the same time. For example, low temperature physical vapor deposition (PVD) processes can achieve a density of 3 g / cm3, but the stress produced can be more compressive due to strong ion bombardment produced by the sputtering process. Adjustments to the PVD process to increase stress, such as by changing precursor distribution or power, can cause density to decrease. Furthermore, conventional low temperature plasma enhanced chemical vapor deposition (PECVD) processes using SiH4and NH3as reactive precursors and typically using a plasma frequency of 13.56 MHz are not able to produce silicon nitride films characterized by both higher density and higher stress. This can be due at least in part to the high intrafilm hydrogen content of these films, which can cause a decrease in quality of the film due to pore formation that can occur with subsequent degassing. The amount of hydrogen incorporation can also decrease film stress by reducing the more tetrahedral network formed when decreasing hydrogen incorporation. Dissociated ammonia can include nitrogen-hydrogen bonded radicals that can be more likely to be incorporated into the film and can further increase hydrogen incorporation. Furthermore, N-H bonds within the deposited film can disadvantageously decrease both density and film stress. 3

[0029] ​The present technology can overcome these problems by utilizing a deposition process with a high frequency plasma formed from a mixture gas of SiH4, N2, and H2. Some conventional PECVD processes use N2 in place of NH3 as a nitrogen source for forming silicon nitride films. Because N2 has a high electron impact dissociation of 24.3 eV, dissociation of N2 in a plasma is weak, such that N2 can not be fully dissociated in a 13.56 MHz plasma. As a result, the resulting silicon nitride film tends to have a high hydrogen content because it is difficult to break the bond between two nitrogen atoms to form a silicon-nitrogen bond. At higher plasma frequencies, the dissociation process of N2 can become more efficient. However, because the silicon-hydrogen bonds in SiH4 cannot be completely removed, there is still a high hydrogen content in the film. Thus, the present technology can increase the frequency to dissociate N2, and can also include H2 gas as a precursor to the plasma, which can advantageously create a chemical annealing atmosphere that promotes desorption of nitrogen-hydrogen bonds. As discussed in further detail below, although the goal can be to reduce the amount of hydrogen incorporation in the film, counterintuitively, incorporating H2 gas with the deposition precursors can reduce the number of nitrogen-hydrogen bonds formed in the silicon nitride film, increase the density of the film, and increase the stress of the film, as compared to conventional low temperature deposition techniques. Incorporating H2 gas can also reduce the hydrogen content within the film and improve the quality of the film. When the nitrogen-hydrogen bonds within the film are reduced due to the incorporation of hydrogen in the plasma precursors, the more volatile hydrogen residue can be pumped out of the film during deposition and exhausted from the processing chamber.

[0030] While the remainder of the disclosure will conventionally identify specific deposition processes that utilize the disclosed technology, it will be readily understood that the systems and methods are equally applicable to other deposition and cleaning chambers, and processes that can occur in the described chambers. Thus, the present technology should not be considered limited to use with these specific deposition processes or chambers. Prior to describing additional details of embodiments in accordance with the present technology, the present disclosure will discuss one possible system and chamber that can be used to perform deposition processes in accordance with embodiments of the present technology.

[0031] Figure 1A top plan view of one embodiment of a processing system 100 showing deposition, etch, bake, and cure chambers according to embodiments is shown. In the figure, a pair of front opening unified pods 102 provide substrates of various sizes that are received by a robot arm 104 and placed into a low pressure holding area 106 before being placed into one of the substrate processing chambers 108a-f positioned in tandem sections 109a-c. A second robot arm 110 can be used to transport substrate wafers from the holding area 106 to the substrate processing chambers 108a-f and back. Each substrate processing chamber 108a-f can be equipped to perform a variety of substrate processing operations including forming stacks of semiconductor materials described herein, in addition to plasma enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, etching, pre-cleaning, degassing, orientation, and other substrate processes including annealing, ashing, etc.

[0032] The substrate processing chambers 108a-f can include one or more system components for depositing, annealing, curing, and / or etching dielectric films or other films on a substrate. In one configuration, two pairs of processing chambers (e.g., 108c-d and 108e-f) can be used to deposit dielectric materials on a substrate, while a third pair of processing chambers (e.g., 108a-b) can be used to etch the deposited dielectric. In another configuration, all three pairs of processing chambers (e.g., 108a-f) can be configured to deposit stacks of alternating dielectric films on a substrate. Any one or more of the processes described can be performed in chambers separate from the manufacturing systems shown in different embodiments. It can be appreciated that the system 100 contemplates additional configurations of deposition, etch, anneal, and cure chambers for dielectric films.

[0033] Figure 2 A schematic cross-sectional view of an exemplary plasma system 200 according to some embodiments of the present technology is shown. The plasma system 200 can illustrate a pair of processing chambers 108 that can be installed in one or more of the tandem sections 109 described above, and according to embodiments of the present technology, the pair of processing chambers 108 can include a lid stack component and can be explained further below. The plasma system 200 can generally include a chamber body 202 having sidewalls 212, a bottom wall 216, and interior sidewalls 201 that define a pair of processing regions 220A and 220B. Each of the processing regions 220A-220B can be similarly configured and can include identical components.

[0034] For example, components thereof can also be included in processing region 220B, which can include a pedestal 228 disposed in the processing region via a passage 222 formed in a bottom wall 216 in plasma system 200. Pedestal 228 can provide a heater suitable for supporting a substrate 229 on an exposed surface of the pedestal, such as a body portion. Pedestal 228 can include a heating element 232 (e.g., a resistive heating element) that can heat and control the substrate temperature at a desired process temperature. Pedestal 228 can also be heated by a remote heating element, such as a lamp assembly or any other heating device.

[0035] The body of pedestal 228 can be coupled to a stem 226 by a flange 233. Stem 226 can electrically couple pedestal 228 with a power outlet or power box 203. Power box 203 can include a drive system that controls the lifting and movement of pedestal 228 within processing region 220B. Stem 226 can also include an electrical power interface to provide electrical power to pedestal 228. Power box 203 can also include an interface for electrical power and temperature indicators, such as a thermocouple interface. Stem 226 can include a base assembly 238 suitable for detachably coupling with power box 203. A circumferential ring 235 is shown above power box 203. In some embodiments, circumferential ring 235 can be a shoulder suitable as a mechanical stop or ground configured to provide a mechanical interface between base assembly 238 and an upper surface of power box 203.

[0036] A rod 230 can be included through a passage 224 formed in bottom wall 216 of processing region 220B and can be used to position a substrate lift pin 261 disposed through the body of pedestal 228. Substrate lift pin 261 can selectively space substrate 229 from pedestal to facilitate substrate 229 exchange with a robot used to bring substrate 229 into and out of processing region 220B through a substrate transfer port 260.

[0037] A chamber lid 204 can be coupled to a top portion of the chamber body 202. The lid 204 can house one or more precursor distribution systems 208 coupled to the lid 204. The precursor distribution system 208 can include a precursor inlet passage 240 that can deliver reactants and cleaning precursors into the processing region 220B through a dual channel showerhead 218. The dual channel showerhead 218 can include an annular bottom plate 248 having a spacer plate 244 disposed intermediate to the faceplate 246. A radio frequency ("RF") source 265 can be coupled to the dual channel showerhead 218, which can provide power to the dual channel showerhead 218 to facilitate generation of a plasma region between the faceplate 246 of the dual channel showerhead 218 and the susceptor 228. In some embodiments, the RF source can be coupled to other portions of the chamber body 202, such as the susceptor 228, to facilitate plasma generation. A dielectric isolator 258 can be disposed between the lid 204 and the dual channel showerhead 218 to prevent the conduction of RF power to the lid 204. A shadow ring 206 can be disposed around the periphery of the susceptor 228, in engagement with the susceptor 228. The dual channel showerhead 218 can have a separation of greater than or about 200 mils, greater than or about 300 mils, greater than or about 400 mils, greater than or about 500 mils, greater than or about 600 mils, or greater. Alternatively or additionally, the dual channel showerhead 218 can have a separation of less than or about 1200 mils, less than or about 1100 mils, less than or about 1000 mils, less than or about 900 mils, less than or about 800 mils, less than or about 700 mils, or less.

[0038] An optional cooling channel 247 can be formed in the annular bottom plate 248 of the precursor distribution system 208 to cool the annular bottom plate 248 during operation. A heat transfer fluid, such as water, ethylene glycol, gas, or the like, can be circulated through the cooling channel 247 such that the bottom plate 248 is maintained at a predefined temperature. A liner assembly 227 can be disposed within the processing region 220B proximate to the sidewalls 201, 212 of the chamber body 202 to prevent the sidewalls 201, 212 from being exposed to the processing environment within the processing region 220B. The liner assembly 227 can include a circumferential pumping cavity 225 that can be coupled to a pumping system 264 configured to evacuate gases and byproducts from the processing region 220B and control the pressure within the processing region 220B. A plurality of exhaust ports 231 can be formed in the liner assembly 227. The exhaust ports 231 can be configured to allow the flow of gases from the processing region 220B to the circumferential pumping cavity 225 in a manner that facilitates processing within the system 200.

[0039] Figure 3Operations of an exemplary method 300 of semiconductor processing according to some embodiments of the present technology are shown. The method can be performed in various processing chambers, including the processing system 200 described above, as well as any other chamber in which plasma deposition can be performed. The method 300 can include a number of optional operations that can or can not be specifically associated with some embodiments of the method according to the present technology. The method 300 can be used to deposit a silicon nitride film on a substrate, such as the substrate 229.

[0040] The method 300 can include processing methods that can include operations for forming a film of material or other deposition operations at high frequency, such as producing DRAM memory or other materials that can be formed with higher density and / or higher stress relative to conventional processes. The method can include optional operations prior to initiating the method 300, or the method can include additional operations. For example, the method 300 can include operations performed prior to the start of the method, including additional deposition, removal, or processing operations. In some embodiments, the method 300 can include flowing a plurality of precursors into a processing chamber at operation 305, which can deliver the precursors into a processing region of a chamber that can house a substrate, such as the region 220, for example. The precursors can be delivered with diatomic hydrogen gas. Additionally, carrier gases such as argon and / or helium can also be used to deliver the precursors.

[0041] In some embodiments, the precursors can include a silicon-containing precursor, such as silane, and a nitrogen-containing precursor, such as diatomic nitrogen. While any silicon-containing precursor can be used in embodiments of the present technology, by using silane, the amount of hydrogen within the processing region can be better controlled, and the amount of hydrogen incorporation within the deposited film can be reduced. The precursors can or can not include additional precursors, such as carrier gases and / or one or more oxygen-containing precursors for depositing an oxide layer. The precursors can also include hydrogen gas. As discussed in further detail below, including diatomic hydrogen gas and the precursors can reduce the number of nitrogen-hydrogen bonds formed in the silicon nitride film, increase the density of the film, and increase the stress of the film compared to conventional low-temperature deposition techniques. Additionally, in some embodiments, the processing precursors can specifically exclude any precursors that can include nitrogen-hydrogen bonds that can affect the properties of the film as previously described. Thus, in some embodiments, the gas-phase material can be free of any nitrogen-hydrogen bonds.

[0042] At operation 310, a plasma of the precursor and diatomic hydrogen can be generated within the processing region, such as by providing RF power to the faceplate to generate a plasma within the processing region 220, although any other processing chamber capable of generating a plasma can similarly be used. The plasma can be generated at any of the previously described frequencies, and can be generated at a frequency greater than or about 15 MHz, greater than or about 20 MHz, greater than or about 27 MHz, greater than or about 40 MHz, or higher. Alternatively or additionally, the plasma can be generated at a frequency less than or about 100 MHz, less than or about 80 MHz, less than or about 60 MHz, or lower. By using a higher frequency plasma, the dissociation of nitrogen can be increased, and the yield can also be increased due to the increase in deposition rate.

[0043] The material formed in the plasma can be deposited on the substrate at operation 315, which can result in a material containing silicon and nitrogen, such as silicon nitride. The deposition can be performed at a substrate or susceptor temperature less than or about 550 °C, less than or about 500 °C, less than or about 450 °C, less than or about 400 °C, or lower. By using a lower temperature, the thermal budget of the DRAM memory can not be exceeded, and damage to the material already deposited on the substrate can be prevented. Additionally, the deposition can be performed at a power greater than or about 25 W, greater than or about 250 W, greater than or about 500 W, greater than or about 750 W, greater than or about 1000 W, greater than or about 1250 W, or higher. By using a higher power, the deposition rate can be increased, which indicates that the dissociation of nitrogen can be a limiting factor in the process. However, as the plasma power is increased, the dissociation of nitrogen can further increase, additional nitrogen radicals can be incorporated into the film, which can reduce the formation of the silicon-nitrogen network, which will be discussed below. Thus, in some embodiments, the plasma power can be maintained at less than or about 3000 W, less than or about 2500 W, less than or about 2000 W, less than or about 1500 W, less than or about 1250 W, less than or about 1000 W, less than or about 900 W, or lower. Additionally, the pressure can be maintained at greater than or about 2 Torr, greater than or about 3 Torr, greater than or about 4 Torr, greater than or about 5 Torr, or higher. Alternatively or additionally, the pressure can be maintained at less than or about 10 Torr, less than or about 9 Torr, less than or about 8 Torr, less than or about 7 Torr, less than or about 6 Torr, or lower.

[0044] Figures 4A-4D An example illustrating the growth mechanism in some deposition processes is described. In this example, a low temperature PECVD is used to deposit a silicon nitride film with silane and diatomic nitrogen precursors. As shown, no gas phase reaction occurs between the silane and diatomic nitrogen. Figure 4A Instead, SiN x Hy Deposition is from SiH m Chemisorption begins with a radical. As Figure 4B shown, when landing on the reactive surface of the growth substrate, the nitrogen radical bonds with a silicon atom and releases a hydrogen atom. This happens at nearly all silicon-hydrogen bond sites due to the low energy of the silicon-hydrogen bond. However, as Figure 4C shown, once the silicon-nitrogen bond is formed, the released hydrogen radical reattaches to the nitrogen’s unpaired electron, which limits or prevents the formation of a stretched silicon-nitrogen bond, which would increase the stress within the film. A large number of nitrogen-hydrogen bonds and silicon-hydrogen bonds remain in the film, which also lowers the density. As Figure 4D shown, the nitrogen atoms build up vapor pressure, and any SiH m radicals that reach the surface are saturated with silicon-nitrogen bonds. Because the silicon-nitrogen bond has a low bond energy, the film eventually becomes nitrogen-rich, as increased nitrogen bonding can occur at every site, which can further limit the formation of a network.

[0045] Figures 4E-4G An example illustrating growth mechanisms including nitrogen and hydrogen precursors, respectively, in accordance with some embodiments of the present technology is described. In this example, a silicon nitride film is deposited using low temperature PECVD by adding diatomic hydrogen to silane and diatomic nitrogen precursors. The addition of diatomic hydrogen creates a chemical annealing atmosphere that promotes desorption of nitrogen-hydrogen bonds. As Figure 4E shown, when diatomic hydrogen gas is added, removal of nitrogen-hydrogen bonds is catalyzed by the presence of free H radicals. This is energetically more favorable than the removal process of silicon-hydrogen bonds. As Figure 4F shown, one or more unpaired electrons on N promote cross-linking of silicon-nitrogen bonds, increasing the tensile stress. As Figure 4G shown, the density of the film is higher because it has fewer nitrogen-hydrogen voids. In this compact film, it is more difficult for nitrogen atoms to land on silicon-hydrogen sites, which results in the film having more silicon-hydrogen bonds and being rich in silicon.

[0046] Figures 5A-5FVarious deposition and film parameters as a function of the flow rate of diatomic hydrogen are described according to some embodiments of the present technology. In this example, a 27 MHz plasma is formed in a PECVD chamber at a temperature of 450 °C. The flow rate of diatomic hydrogen can be greater than or about 100 sccm, greater than or about 1000 sccm, greater than or about 2000 sccm, greater than or about 3000 sccm, greater than or about 4000 sccm, or greater. However, as the hydrogen flow rate continues to increase, as will be explained below, although nitrogen-hydrogen bonding may be limited, which may stabilize the density, the increase in available hydrogen may affect formation and may increase the generation of silicon-silicon bonding within the film, which may reduce film stress. Therefore, in some embodiments, the flow rate of diatomic hydrogen may be less than or about 5000 sccm and may remain less than or about 4000 sccm, less than or about 3000 sccm, less than or about 2000 sccm, or less, depending on the target internal stress within the film. The flow rate of diatomic hydrogen can be adjusted to achieve various deposition and film properties, as discussed in further detail below.

[0047] like Figure 5A As shown, the deposition rate of the film increases as a function of the flow rate of diatomic hydrogen. Furthermore, for each flow rate, the first deposition rate 505 of the film deposited at the higher power of 1250 W is greater than the second deposition rate 510 of the film deposited at the lower power of 750 W. In this example, the deposition rate can be greater than or approximately 1200 Å / min, greater than or approximately 1300 Å / min, greater than or approximately 1400 Å / min, greater than or approximately 1500 Å / min, greater than or approximately 1600 Å / min, greater than or approximately 1700 Å / min, greater than or approximately 1800 Å / min, or greater.

[0048] like Figure 5B As shown, the membrane stress exhibits peak values ​​that vary with power. For example, the first stress 515 of a membrane deposited at a higher power of 1250 W has a higher peak flow rate than the second stress 520 of a membrane deposited at a lower power of 750 W. This is because the higher power generates more nitrogen radicals, which are incorporated into the membrane during the deposition process. Furthermore, the peak value of the first stress 515 of the membrane deposited at the higher power may be lower than the peak value of the second stress 520 of the membrane deposited at the lower power. In this example, the stress can be greater than or approximately 300 MPa, greater than or approximately 400 MPa, greater than or approximately 500 MPa, greater than or approximately 600 MPa, greater than or approximately 700 MPa, greater than or approximately 800 MPa, greater than or approximately 900 MPa, or greater.

[0049] likeFigure 5C As shown, the membrane density exhibits a distribution that varies with power. For example, the first density 525 of the membrane deposited at a higher power of 1250 W increases as a function of flow rate before leveling off. On the other hand, the second density 530 of the membrane deposited at a lower power of 750 W increases more rapidly as a function of flow rate, reaching a peak and then gradually decreasing. In this example, the density can be greater than or approximately 2.50 g / cm³. 3 Greater than or approximately 2.55 g / cm³ 3 Greater than or approximately 2.60 g / cm³ 3 Greater than or approximately 2.65 g / cm³ 3 Greater than or approximately 2.70 g / cm³ 3 Greater than or approximately 2.75 g / cm³ 3 Greater than or approximately 2.80 g / cm³ 3 Greater than or approximately 2.85 g / cm³ 3 Greater than or approximately 2.90 g / cm³ 3 Or even larger.

[0050] like Figure 5D As shown, the refractive index of the film increases as a function of the diatomic hydrogen flow rate. This indicates that a lower nitrogen-hydrogen bond density results in a more Si-rich film, which may lead to an increase in refractive index. Furthermore, for each flow rate, the first refractive index 605 of the film deposited at the higher power of 1250 W is lower than the second refractive index 610 of the film deposited at the lower power of 750 W. In this example, the refractive index can be greater than or approximately 1.75, greater than or approximately 1.80, greater than or approximately 1.85, greater than or approximately 1.90, greater than or approximately 1.95, greater than or approximately 2.00, greater than or approximately 2.05, greater than or approximately 2.10, greater than or approximately 2.15, greater than or approximately 2.20, or greater.

[0051] like Figure 5E As shown, the ratio of silicon-hydrogen bond density to silicon-nitrogen bond density increases as a function of the diatomic hydrogen flow rate. Furthermore, for each flow rate, the first ratio 535 of silicon-hydrogen bond density to silicon-nitrogen bond density of the film deposited at the higher power of 1250 W is lower than the second ratio 540 of silicon-hydrogen bond density to silicon-nitrogen bond density of the film deposited at the lower power of 750 W. In this example, the ratio of silicon-hydrogen bond density to silicon-nitrogen bond density can be greater than or about 0.0%, greater than or about 0.4%, greater than or about 0.8%, greater than or about 1.2%, or greater.

[0052] like Figure 5FAs shown, the ratio of nitrogen-hydrogen bond density to silicon-nitrogen bond density decreases as a function of the flow rate of diatomic hydrogen. Further, for each flow rate, the first ratio 555 of nitrogen-hydrogen bond density to silicon-nitrogen bond density for a film deposited at a higher power of 1250 W is lower than the second ratio 560 of nitrogen-hydrogen bond density to silicon-nitrogen bond density for a film deposited at a lower power of 750 W. In this example, the ratio of nitrogen-hydrogen bond density to silicon-nitrogen bond density can be less than or about 25%, less than or about 20%, less than or about 15%, less than or about 10%, less than or about 5%, or lower.

[0053] As shown in Figure 5E and Figure 5F the nitrogen-hydrogen bond density drops sharply while the silicon-hydrogen bond density increases modestly as a small amount of diatomic hydrogen is added. This increases both the density and the stress of the film. The lower nitrogen-hydrogen bond density results in a film richer in silicon, which can be evidenced by the corresponding increase in refractive index shown in Figure 5D Further, as shown in Figure 5B and Figure 5C both the first density 525 and the second density 530 reach a saturation level generally above a certain flow rate level corresponding to Figure 5F the sufficient drop in nitrogen-hydrogen bond density shown in

[0054] As discussed above, SiH4may be used as a precursor for silicon. The flow rate of silane can be greater than or about 10 seem, greater than or about 100 seem, greater than or about 200 seem, greater than or about 300 seem, greater than or about 400 seem, or greater. Alternatively or additionally, the flow rate of silane can be less than or about 1000 seem, less than or about 900 seem, less than or about 800 seem, less than or about 700 seem, or less. Further, as discussed above, N2may be used as a precursor for nitrogen. The flow rate of N2may be greater than or about 1000 seem, greater than or about 2000 seem, greater than or about 3000 seem, greater than or about 4000 seem, greater than or about 5000 seem, or greater. Alternatively or additionally, the flow rate of N2may be less than or about 10,000 seem, less than or about 9000 seem, less than or about 8000 seem, less than or about 7000 seem, or less.

[0055] Some of the methods discussed above can perform the deposition process without using NH3as a precursor, and can explicitly exclude ammonia. In other examples, NH3may be used as a precursor for nitrogen. The flow rate of NH3may be greater than or about 1000 seem, greater than or about 2000 seem, greater than or about 3000 seem, greater than or about 4000 seem, greater than or about 5000 seem, or greater. Alternatively or additionally, the flow rate of NH3may be less than or about 10,000 seem, less than or about 9000 seem, less than or about 8000 seem, less than or about 7000 seem, or less.

[0056] Further, as discussed above, a carrier gas such as argon and / or helium can be used to transport the precursors. The flow rate of argon can be greater than or about 0 seem, greater than or about 1000 seem, greater than or about 2000 seem, greater than or about 3000 seem, greater than or about 4000 seem, or greater. Alternatively or additionally, the flow rate of argon can be less than or about 10,000 seem, less than or about 9000 seem, less than or about 8000 seem, less than or about 7000 seem, or less. Similarly, the flow rate of helium can be greater than or about 0 seem, greater than or about 1000 seem, greater than or about 2000 seem, greater than or about 3000 seem, greater than or about 4000 seem, or greater. Alternatively or additionally, the flow rate of helium can be less than or about 10,000 seem, less than or about 9000 seem, less than or about 8000 seem, less than or about 7000 seem, or less.

[0057] The above-described methods can also be used to reduce the amount of hydrogen formed in the silicon nitride film. Conventional low temperature PECVD processes typically produce films with hydrogen incorporation of more than 10%, which can degrade the quality of the film due to subsequent pore formation. In contrast, the above-described methods can include diatomic hydrogen with the silicon-containing precursor and the nitrogen-containing precursor, which can counterintuitively reduce the amount of hydrogen in the film to less than or about 10%, less than or about 9%, less than or about 8%, less than or about 7%, or less. This can improve the quality of the film and facilitate subsequent removal with a nitride-specific etchant.

[0058] In the preceding description, for purposes of explanation, numerous details are set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that certain embodiments can be practiced without some or all of these details.

[0059] Having disclosed several embodiments, those skilled in the art will recognize, in light of the disclosure herein, that many changes can be made within the spirit and scope of the embodiments. Also, the various known processes and elements have not been described in detail in order to avoid unnecessarily obscuring the disclosure. Accordingly, the above description should not be taken as limiting.

[0060] Where a range of values is provided, it is understood that each intervening value, to the minimum resolvable between the upper and lower limit of that range, is also specifically disclosed. Any smaller range between any stated value or intervening value in the stated range, is encompassed. The upper and lower limits of these smaller ranges can independently be included or excluded in the range, and the endpoints are included in the smaller ranges. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0061] As used in this description and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a material" includes a plurality of such materials, and reference to "the precursor" includes reference to one or more precursors known to one skilled in the art and equivalents thereof, and so forth.

[0062] Also, as used in this specification and the appended claims, the terms "comprise(s)," "comprising," "contain(s)," "containing," "include(s)," and "including," when used in this specification and in the following claims, are intended to be open-ended terms i.e., conditions of the body of the claims. Thus, terms such as "comprising," "including," and "containing" should be interpreted as including the possibility of additional non-specified features, integers, steps, operations, acts, or groups thereof.

Claims

1. A method comprising: A silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen are flowed into the processing region of a semiconductor processing chamber, wherein a substrate is housed in the processing region of the semiconductor processing chamber. A plasma is formed comprising the silicon-containing precursor, the nitrogen-containing precursor, and the diatomic hydrogen, wherein the plasma is formed at a frequency of 15 MHz or higher; and Silicon nitride material is deposited on the substrate.

2. The method of claim 1, wherein the silicon nitride material has a density of 2.85 g / cm³ or higher. 3 Density characterization.

3. The method of claim 1, wherein the silicon nitride material is characterized by a stress of 400 MPa or higher.

4. The method of claim 1, wherein the silicon nitride material is characterized by a refractive index greater than or about 1.

75.

5. The method of claim 1, wherein the silicon nitride material comprises less than or about 10% hydrogen.

6. The method of claim 1, wherein greater than or about 100 sccm of the diatomic hydrogen flows into the processing region of the semiconductor processing chamber.

7. The method of claim 6, wherein less than or about 5000 sccm of the diatomic hydrogen flows into the processing region of the semiconductor processing chamber.

8. The method of claim 1, wherein the plasma is formed at a temperature below or about 550°C.

9. The method of claim 1, wherein the frequency is higher than or about 27 MHz.

10. A method comprising: A silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen are flowed into the processing region of a semiconductor processing chamber, wherein a substrate is housed in the processing region of the semiconductor processing chamber. A plasma is formed comprising the silicon-containing precursor, the nitrogen-containing precursor, and the diatomic hydrogen, wherein the plasma does not contain any material having nitrogen-hydrogen bonds; as well as Silicon nitride material is deposited on the substrate, wherein: The silicon nitride material has a density of 2.85 g / cm³ or higher. 3 The density characterization, and The silicon nitride material is characterized by stresses of 400 MPa or higher.

11. The method of claim 10, wherein the silicon nitride material is characterized by a refractive index greater than or about 1.

75.

12. The method of claim 10, wherein the silicon nitride material comprises less than or about 10% hydrogen.

13. The method of claim 10, wherein greater than or about 100 sccm of the diatomic hydrogen flows into the processing region of the semiconductor processing chamber.

14. The method of claim 13, wherein less than or about 5000 sccm of the diatomic hydrogen flows into the processing region of the semiconductor processing chamber.

15. The method of claim 10, wherein the plasma is formed at a temperature below or about 550°C.

16. The method of claim 10, wherein the plasma is formed at a frequency of 15 MHz or higher.

17. The method of claim 16, wherein the frequency is higher than or about 27 MHz.

18. A method comprising: A silicon-containing precursor, a nitrogen-containing precursor, and diatomic hydrogen are flowed into the processing region of a semiconductor processing chamber, wherein a substrate is housed in the processing region of the semiconductor processing chamber. A plasma is formed comprising the silicon-containing precursor, the nitrogen-containing precursor, and the diatomic hydrogen. as well as Silicon nitride material is deposited on the substrate, wherein: The diatomic hydrogen atoms, at a concentration greater than or approximately 100 sccm, flow into the processing region of the semiconductor processing chamber, and The diatomic hydrogen, less than or approximately 5000 sccm, flows into the processing region of the semiconductor processing chamber.

19. The method of claim 18, wherein the silicon nitride material has a density of 2.85 g / cm³ or higher. 3 Density characterization.

20. The method of claim 18, wherein the silicon nitride material is characterized by a stress of 400 MPa or higher.

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