Improve tribological property of diamond film

Abstract

To provide a method for manufacturing an integrated circuit.SOLUTION: In a method for processing a substrate 200 using nanocrystalline diamond as a hard mask instead of amorphous carbon, the nanocrystalline diamond 208 is used as the hard mask to produce a smooth surface. The method includes two processing parts, where two separate nanocrystalline diamond recipes are combined, and the first and second recipes are cycled to produce a nanocrystalline diamond hard mask with high hardness, high modulus, and a smooth surface. The first recipe is also followed by an inert gas plasma smoothing process, and then the first recipe is cycled to produce the high hardness, high modulus, and smooth surface.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001]

[0002] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of electronic device manufacturing, and in particular to integrated circuit (IC) manufacturing. More specifically, embodiments of the present disclosure provide methods for depositing nanocrystalline diamond films. [Background technology]

[0002]

[0003] As the semiconductor industry introduces new generations of integrated circuits (ICs) with higher performance and greater functionality, the density of elements forming such ICs is increasing, while the dimensions, size, and spacing of individual components or elements are decreasing. While in the past, such reductions were limited only by the ability to define structures using photolithography, device geometries with dimensions measured in μm or nm have created new limiting factors, such as the conductivity of metal elements, the dielectric constant of the insulating material(s) used between elements, or challenges in 3D NAND or DRAM processes. These limitations can be addressed by more durable and harder hard masks.

[0003]

[0004] A straightforward way to reduce the cost per bit and increase chip density in 3D NAND is by adding more layers. One of the key steps in 3D NAND technology is slit etching, which precedes silicon nitride (SiN) recessing for metal contact deposition. As the number of layers increases at each technology node, the thickness of the hard mask must increase proportionally to withstand the high-aspect etch profile (uniform etching from top to bottom) required to control the slit etch profile. Traditionally, very high-quality hard mask films have been used, offering high etch selectivity, exceptional hardness, and high density. Current hard mask films include pure or doped plasma-enhanced chemical vapor deposition (PECVD) amorphous carbon (aC:H)-based films due to their high hardness and modulus, film transparency, and ease of removal after slit etching. However, PECVD amorphous carbon hard mask films suffer from issues such as delamination / peeling at the bevel (a major problem in downstream etching processes), becoming more opaque in thicker films (photoalignment issues), and poor morphology, leading to pillar striation, one sided bow, and pillar twisting.

[0004]

[0005] Nanocrystalline diamond is known as a hard material that can be used as a hard mask in semiconductor device processing. Nanocrystalline diamond hard mask films have high hardness and elastic modulus, but also high surface roughness. Therefore, there is a need for hard masks that have high hardness and elastic modulus but low surface roughness. Summary of the Invention

[0005]

[0006] Apparatus and methods for manufacturing integrated circuits are described. In one or more embodiments, a processing method is described. In one embodiment, the processing method comprises depositing a first nanocrystalline diamond layer on a substrate, the first nanocrystalline diamond layer having a first thickness, a first roughness, a first hardness, and a first elastic modulus, and depositing a second nanocrystalline diamond layer on the first nanocrystalline diamond layer, the second nanocrystalline diamond layer having a second thickness and a second roughness, wherein the first thickness is greater than the second thickness and the second roughness is less than the first roughness.

[0006]

[0007] In another embodiment, a treatment method comprises depositing a first nanocrystalline diamond layer on a seed layer, the first nanocrystalline diamond layer having a first thickness, a first roughness, a first hardness and a first modulus of elasticity, and exposing the first nanocrystalline diamond layer to an inert gas plasma to form a smooth nanocrystalline diamond layer.

[0007]

[0008] In one or more embodiments, an electronic device is described, the memory device including a memory stack including a plurality of alternating layers of a first material and a second material on a substrate, a nanocrystalline diamond layer on the memory stack, the nanocrystalline diamond layer having a roughness of less than about 15 nm, and a memory channel extending from a top surface of the memory stack to the substrate.

[0008]

[0009] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure, briefly summarized above, can be made by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure, as the present disclosure may admit of other equally effective embodiments. The embodiments described herein are described by way of example, not limitation, using the accompanying drawings, in which like elements are designated by like reference numerals. [Brief explanation of the drawings]

[0009] [Figure 1A]

[0010] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 1B]

[0011] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 1C]

[0012] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 1D]

[0013] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 2A]

[0014] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 2B]

[0015] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 2C]

[0016] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 2D]

[0017] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 3A]

[0018] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 3B]

[0019] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 3C]

[0020] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 4A]

[0021] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 4B]

[0022] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 4C]

[0023] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 4D]

[0024] 1 illustrates a cross-sectional view of a substrate according to one or more embodiments. [Figure 5]

[0025] 1 illustrates a flow diagram of a method according to one or more embodiments. [Figure 6]

[0026] 1 illustrates a flow diagram of a method according to one or more embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0027] Before describing several example embodiments of the present disclosure, it is to be understood that the present disclosure is not limited to the details of construction or process steps set forth in the following description. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0011]

[0028] As used herein, "substrate" refers to any substrate or material surface formed on a substrate on which film processing is performed during a manufacturing process. For example, substrate surfaces on which processing may be performed include materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes to polish, etch, reduce, oxidize, hydroxylate, anneal, and / or bake the substrate surface. In addition to film processing directly on the surface of the substrate itself, the present disclosure contemplates that any of the disclosed film processing steps may be performed on an underlying layer formed on the substrate, as disclosed in more detail below. The term "substrate surface" is intended to include such underlying layers, as the context indicates. Thus, for example, when a film / layer or partial film / layer is deposited on a substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0012]

[0029] As used herein and in the appended claims, the terms "precursor," "reactant," "reactant gas," and the like are used interchangeably to refer to any gas species capable of reacting with the substrate surface.

[0013]

[0030] The term "nanocrystalline diamond" as used herein refers to a solid film of diamond typically grown on a substrate such as silicon. Nanocrystallinity is the result of enhanced renucleation reactions during diamond growth, and diamond crystal growth is interrupted due to fluctuations in the surrounding environment, such as the amount of radical species, temperature, and pressure. Diamond nucleation is determined by hydrogen atoms, which play an important role in promoting the adsorption of external carbon atoms and etching away non-diamond phases, and is thought to be a competition between diamond growth and etching. Nanocrystalline diamond is primarily composed of small diamond crystals in the shape of nanospheres or nanopillars, with amorphous carbon typically distributed between the surrounding crystals or accumulating within the grain boundaries. Nanocrystalline diamond is used as a hard mask material in semiconductor applications due to its chemical inertness, optical transparency, and good mechanical properties.

[0014]

[0031] In one or more embodiments, plasma-enhanced chemical vapor deposition (PECVD) is widely used to deposit nanocrystalline diamond films due to its cost-effectiveness and versatility in film properties. In a PECVD process, a hydrocarbon source, such as a gas-phase hydrocarbon or liquid-phase hydrocarbon vapor entrained in a carrier gas, is introduced into a PECVD chamber. A plasma is then initiated in the chamber to generate excited CH radicals. The excited CH radicals chemically bond to the surface of a substrate placed in the chamber, forming the desired nanocrystalline diamond film thereon. The embodiments described herein with reference to a PECVD process may be carried out using any suitable thin film deposition system. Examples of suitable systems include the DXZ® processing chamber, the PRECISION 5000® system, the PRODUCER® system, the PRODUCER® GT™ system, the PRODUCER® XP Precision™ system, the PRODUCER® SE™ system, the Sym3® processing chamber, and the CENTURA® system, which may use a Mesa™ processing chamber, all of which are commercially available from Applied Materials, Inc., Santa Clara, Calif. Other tools capable of performing PECVD processes could also benefit from the embodiments described herein. Furthermore, any system capable of the PECVD processes described herein may be advantageously used. Any apparatus described herein is exemplary and should not be understood or interpreted as limiting the scope of the embodiments described herein.

[0015]

[0032] Device manufacturers using carbon-based hardmask layers must meet the following key requirements: (1) high selectivity of the hardmask during dry etching of the underlying material, (2) low film roughness, (3) low film stress, and (4) film strippability. As used herein, the term "dry etching" generally refers to etching processes in which the material is not dissolved by immersion in a chemical solution and includes methods such as plasma etching, reactive ion etching, sputter etching, and gas-phase etching.

[0016]

[0033] In one or more embodiments, a nanocrystalline diamond layer is formed on a substrate. The process of one or more embodiments advantageously produces a nanocrystalline diamond layer that has high density, high hardness, high etch selectivity, low stress, and excellent thermal conductivity.

[0017]

[0034] Hard masks are used as etch stop layers in semiconductor processing. Ashable hard masks have a chemical composition that allows them to be removed by a technique called ashing once they have served their purpose. Ashable hard masks are generally composed of carbon and hydrogen with trace amounts of one or more dopants (e.g., nitrogen, fluorine, boron, silicon). In a typical application, after etching, the hard mask has served its purpose and is removed from the underlying layer. This is generally achieved, at least in part, by ashing, also known as "plasma ashing" or "dry stripping." A substrate bearing the hard mask to be ashed, typically a partially fabricated semiconductor wafer, is placed in a chamber under reduced pressure, oxygen is introduced, and the substrate is exposed to radio frequency power, which generates oxygen radicals (plasma). The radicals react with the hard mask, oxidizing it to water, carbon monoxide, and carbon dioxide. In some cases, complete removal of the hard mask may be achieved by following ashing with an additional wet or dry etching process, for example, when the ashing-compatible hard mask leaves any residue that cannot be removed by ashing alone.

[0018]

[0035] Hard mask layers are often used in narrow and / or deep contact etching applications where the photoresist may not be thick enough to mask the underlying layers, especially as critical dimensions shrink.

[0019]

[0036] V-NAND or 3D-NAND structures are used in flash memory applications. V-NAND devices are vertically stacked NAND structures with many cells arranged in blocks. As used herein, the term "3D NAND" refers to a type of electronic (solid-state) non-volatile computer storage memory in which memory cells are stacked in multiple layers. 3D NAND memory generally includes multiple memory cells that include floating gate transistors. Traditionally, 3D NAND memory cells include multiple NAND memory structures arranged in three dimensions around a bit line.

[0020]

[0037] A key step in 3D NAND technology is slit etching. As the number of layers increases with each technology node, the thickness of the hard mask film must increase proportionally to withstand the high-aspect ratio etch profile required to control the slit etching profile. Currently, amorphous carbon (aC:H) films are used due to their high hardness and ease of peeling after slit etching. However, amorphous carbon hard mask films suffer from delamination and poor morphology at the slopes, resulting in pillar groove formation.

[0021]

[0038] Tribology is the science and engineering of surfaces interacting in relative motion. Tribology includes the study and application of the principles of friction, lubrication, and wear. In one or more embodiments, nanocrystalline diamond is advantageously used as a hard mask instead of amorphous carbon. Nanocrystalline diamond hard mask films offer high hardness and high modulus, but can also result in high levels of surface roughness. Accordingly, in one or more embodiments, a method of processing a substrate is provided in which nanocrystalline diamond is used as a hard mask. The processing method results in a smooth surface. In one or more embodiments, the method includes two processing sections. In one embodiment, two separate nanocrystalline diamond recipes are combined. The first recipe provides high hardness and high modulus, and the second recipe provides a smooth surface. The first and second recipes are cycled to achieve a nanocrystalline diamond hard mask with high hardness, high modulus, and a smooth surface. In another embodiment, the first recipe is followed by an inert gas plasma smoothing process, and then the first recipe is cycled to achieve a high hardness, high modulus, and smooth surface.

[0022]

[0039] The processing method of one or more embodiments advantageously maintains the hardness and modulus of the nanocrystalline diamond hard mask film while maintaining low surface roughness. The high hardness, high modulus, and improved surface roughness of nanocrystalline diamond hard mask films allow them to be used as hard masks to overcome challenges faced with amorphous carbon-based films.

[0023]

[0040] In one or more embodiments, the density, and more importantly, Young's modulus, of the nanocrystalline diamond layer 108, 208 is improved to achieve greater etch selectivity. One of the main challenges in achieving increased etch selectivity and improved Young's modulus is the high compressive stress of such films, which results in large wafer bow, making them unsuitable for applications. Therefore, there is a need for nanocrystalline diamond films with high density and high modulus (e.g., higher sp3 content) that have high etch selectivity along with low stress (e.g., <-500 MPa).

[0024]

[0041] Embodiments described herein include improved methods for producing nanocrystalline diamond hard mask films with high density (e.g., >1.8 g / cc), high Young's modulus (e.g., >150 GPa), and low stress (e.g., <-500 MPa). In one or more embodiments, the Young's modulus is measured at room or ambient temperature, or at a temperature in the range of about 22°C to about 25°C. In one or more embodiments, the Young's modulus of the nanocrystalline diamond film may be greater than 250 GPa. In other embodiments, the Young's modulus of the nanocrystalline diamond film may be greater than 300 GPa, or greater than 350 GPa.

[0025]

[0042] In one or more embodiments, the density of the nanocrystalline diamond film is greater than about 3.0 g / cc.

[0026]

[0043] 1A-1D show schematic cross-sectional views of a substrate 100 at different stages of an integrated circuit fabrication sequence, a first recipe, incorporating a nanocrystalline diamond layer as a hard mask. In FIGS. 1A-1D, the deposited nanocrystalline diamond layer 108 has a thickness T1, a high elastic modulus (E>250 GPa), and a high surface roughness (Ra>25 nm). In one or more embodiments, the first nanocrystalline diamond layer 108 has a thickness T1 in the range of about 250 nm to about 650 nm. In one or more embodiments, the roughness of the nanocrystalline diamond layer 108, as measured by atomic force microscopy (AFM), is greater than 25 nm.

[0027]

[0044] 2A-2D show schematic cross-sectional views of a substrate 200 at different stages of an integrated circuit fabrication sequence, a second recipe, incorporating a nanocrystalline diamond layer as a hard mask. In FIGS. 2A-2D, the deposited nanocrystalline diamond layer 208 has a thickness T2, a high elastic modulus (E>250 GPa), and a low surface roughness (Ra<15 nm). In one or more embodiments, the second nanocrystalline diamond layer 208 has a thickness T2 in the range of about 5 nm to about 200 nm. In one or more embodiments, the roughness of the nanocrystalline diamond layer 208, as measured by atomic force microscopy (AFM), is less than about 15 nm.

[0028]

[0045] 1A shows a cross-sectional view of a device 100. In one or more embodiments, the device 100 may be a NAND device. The device 100 includes a substrate 102, multiple device layers 104, 106, and a nanocrystalline diamond mask layer 108 formed on the multiple device layers 104, 106.

[0029]

[0046] 2A shows a cross-sectional view of a device 200. In one or more embodiments, the device 200 may be a NAND device. The device 200 includes a substrate 202, multiple device layers 204, 206, and a nanocrystalline diamond mask layer 208 formed on the multiple device layers 204, 206.

[0030]

[0047] In one or more embodiments, the substrate 102, 202 may be any semiconductor substrate known in the art, such as single crystal silicon, IV-IV compounds such as silicon germanium (Si-Ge) or silicon germanium carbon (Si-Ge-C), III-V compounds, II-VI compounds, epitaxial layers on such substrates, or any other semiconductor or non-semiconductor material such as silicon oxide, glass, plastic, metal, or ceramic substrates. In one or more embodiments, the substrate 102, 202 may include integrated circuits fabricated thereon, such as drive circuitry for a memory device (not shown).

[0031]

[0048] In one or more embodiments, multiple device layers 104, 106, 204, 206 can be formed on the surface of the substrate 102, 202. The multiple device layers 104, 106, 204, 206 can be stacked layers that form components of a 3D vertical NAND structure. The components can be formed by all or part of multiple device layers (e.g., dielectric or individual charge storage segments). The dielectric portions can be independently selected from any one or more of the same or different electrically insulating materials, such as silicon oxide, silicon nitride, silicon oxynitride, or other high-k insulating materials. In one embodiment, the structure can include silicon oxide / silicon nitride pairs deposited in an alternating manner. The pairs can have a total height between 100 and 600 Å. The number of pairs can be greater than 10 pairs, such as 32 pairs, 64 pairs, or more.

[0032]

[0049] In one or more embodiments, the nanocrystalline diamond layer 108, 208 is a crystalline carbon layer with a high sp3 content and a small crystal size. The most common chemical bonds in amorphous carbon and nanocrystalline carbon are three-fold (sp2) and four-fold (sp3) bonding coordination. In the sp3 configuration, a carbon atom forms four sp3 orbitals and forms strong sigma bonds with neighboring atoms. In carbon films with a high sp3 content, the sp3 content is greater than 80%, for example, greater than about 90%, or greater than about 95%. The nanocrystalline diamond layer 108, 208 has a high sp3 content (e.g., nanocrystalline diamond grains) and is supported by an sp2 matrix (e.g., graphite). As used herein, a small crystal size is a crystal size less than 6 nm, for example, between 2 nm and 5 nm.

[0033]

[0050] In one or more embodiments, the nanocrystalline diamond layer 108 produced by the first recipe has a surface roughness with a root mean square of height deviation greater than 25 nm. In one or more embodiments, the first recipe may include a gas flow of methane (CH4) / carbon dioxide (CO2) / hydrogen (H2) at a flow rate range that produces a total flow rate of 100%. The nanocrystalline diamond film is deposited using a microwave power of 2 to 12 kW, a pressure of 0.1 to 1 Torr, and a temperature range of 500°C to 650°C.

[0034]

[0051] In one or more embodiments, the nanocrystalline diamond layer 208 produced by the second recipe has a surface roughness with a height root mean square deviation of less than about 15 nm. In one or more embodiments, the second recipe may include a gas flow of methane (CH4), carbon dioxide (CO2), hydrogen (H2), and argon (Ar) at a flow rate range that produces a total flow rate of 100%. The nanocrystalline diamond film is deposited using 2 to 12 kW of microwave power pulsed at 10-90%, a pressure of 0.1 to 1 Torr, and a temperature range of 500°C to 650°C.

[0035]

[0052] In one or more embodiments, the nanocrystalline diamond layer 108, 208 has a density of 3 g / cm 3 density, such as 2.5g / cm 3 and 3.5 g / cm 3 In one or more embodiments, the nanocrystalline diamond layer 108, 208 has a stress of between -50 MPa and -150 MPa, for example, between -80 MPa and -120 MPa. The nanocrystalline diamond layer 108, 208 has a blanket etch selectivity of between 2 and 4.

[0036]

[0053] In some embodiments, an antireflective coating 110, 210 is on the nanocrystalline diamond layer 108, 208 and a photoresist 112, 212 is on the antireflective coating 110, 210. In some embodiments, the antireflective coating 110, 210 is a dielectric antireflective coating (DARC). Referring to Figures 1B and 2B, the antireflective coating 110, 210 is patterned to form openings 113, 213 that expose portions of the top surfaces of the nanocrystalline diamond layers 108, 208.

[0037]

[0054] 1C and 1D and 2C and 2D, the devices 100, 200 include channels 114, 214. The channels 114, 214 are formed through the nanocrystalline diamond layers 108, 208 and the multiple device layers 104, 106, 204, and 206. The channels 114, 214 may be substantially perpendicular to the top surface of the substrates 102, 202. For example, the channels 114, 214 may have a pillar shape. The channels 114, 214 may extend substantially perpendicular to the top surface of the substrates 102, 202. In some embodiments, the channels 114, 214 may be filled features. In some other embodiments, the channels 114, 214 may be hollow. In such embodiments, an insulating filler material (not shown) may be formed to fill the hollow portion surrounded by the channels 114, 214. The insulating fill material may include any electrically insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or other high-k insulating material.

[0038]

[0055] 1D and 2D, in one or more embodiments, the anti-reflective coating 110, 210 may be removed after the channels 114, 214 are formed.

[0039]

[0056] Any suitable semiconductor material can be used for the channel 114, 214, such as silicon, germanium, silicon germanium, or other compound semiconductor materials such as III-V, II-VI, or conductive or semiconducting oxides, or other materials. The semiconductor material may be amorphous, polycrystalline, or single crystalline. The semiconductor channel material may be formed by any suitable deposition method. For example, in one embodiment, the semiconductor channel material is deposited by low-pressure chemical vapor deposition (LPCVD). In other embodiments, the semiconductor channel material may be a recrystallized polycrystalline semiconductor material formed by recrystallizing an initially deposited amorphous semiconductor material.

[0040]

[0057] In one or more embodiments, the nanocrystalline diamond layer 108 produced according to the first recipe has a thickness T1. In one or more embodiments, the nanocrystalline diamond layer 108 has a thickness T1 in the range of about 500 Å to about 10,000 Å. Depending on the etch chemistry of the energy sensitive resist material 112 used in the manufacturing sequence, an optional capping layer (not shown) may be formed on the nanocrystalline diamond layer 108 prior to the formation of the energy sensitive resist material 112. The optional capping layer acts as a mask for the nanocrystalline diamond layer 108 and protects the nanocrystalline diamond layer 108 from the energy sensitive resist material 112 when a pattern is transferred therein.

[0041]

[0058] In one or more embodiments, the nanocrystalline diamond layer 208 produced according to the second recipe has a thickness T2. In one or more embodiments, the nanocrystalline diamond layer 208 has a thickness T2 in the range of about 100 Å to about 500 Å.

[0042]

[0059] As depicted in Figures 1A and 2A, an energy sensitive resist material 112, 212 may be formed on the nanocrystalline diamond layer 108, 208. The layer of energy sensitive resist material 112, 212 may be spin-coated onto the substrate to a thickness in the range of about 2000 Å to about 6000 Å. Most energy sensitive resist materials are sensitive to ultraviolet (UV) radiation having a wavelength of less than about 450 nm, and in some applications, ultraviolet (UV) radiation having a wavelength of 245 nm or 193 nm. A pattern is introduced into the layer of energy sensitive resist material 112, 212. After the energy sensitive resist material 112, 212 is developed, the desired pattern of apertures / openings 111, 211 is present in the energy sensitive resist material 112, 212, as shown in Figures 1A and 2A. Then, referring to Figures 1B and 2B, the pattern defined in the energy sensitive resist material 112, 212 is transferred through the anti-reflective coating 110, 210 using the energy sensitive resist material 112, 212 as a mask to form openings / apertures 113, 213.

[0043]

[0060] 1C and 2C, the pattern defined in the antireflective coating 110, 210 is transferred through the nanocrystalline diamond layer 108, 208. A suitable chemical etchant is used to selectively etch the nanocrystalline diamond layer 108, 208 and the plurality of material layers 104, 106, 204, 206 overlying the antireflective coating 110, 210 so as to extend the openings 113, 213 down to the substrate 102, 202 to form channels 114, 214. Suitable chemical etchants include ozone, oxygen, or ammonia plasma.

[0044]

[0061] Current carbon hard mask films are deposited at very high temperatures and have low hydrogen (H) content, but the films are predominantly sp2, resulting in low density and modulus, which reduces etch selectivity and pattern integrity. Modulus is a measure of the mechanical strength of the film. Films with low modulus, especially thick films, suffer from line wiggling and other problems.

[0045]

[0062] 3A-3C show cross-sectional views of a device 300 being processed according to a method of one or more embodiments. FIG. 5 shows a process flow diagram of a method 500 according to one or more embodiments. In some embodiments, a substrate is provided for processing prior to operation 502. As used in this context, the term "provided" means that the substrate is placed in a location or environment for further processing. In one or more embodiments, the substrate is maintained at a temperature in the range of about 200° C. to about 1000° C., including in the range of about 500° C. to about 650° C.

[0046]

[0063] In one or more embodiments, the process chamber used may be any CVD process chamber having a plasma source (e.g., remote, microwave, capacitively coupled plasma (CCP), or inductively coupled plasma (ICP)), such as one of the process chambers described above. In some embodiments, the flow rates and other process parameters described below are for a 300 mm substrate. It should be understood that these parameters can be adjusted based on the size of the substrate being processed and the type of chamber used without departing from the embodiments disclosed herein.

[0047]

[0064] As used herein, "substrate surface" refers to any substrate or material surface formed on a substrate on which film processing can be performed. For example, substrate surfaces on which processing can be performed include materials such as silicon, silicon oxide, silicon nitride, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other material such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrate surfaces can also include dielectric materials such as silicon dioxide and carbon-doped silicon oxide. Substrates can have a variety of dimensions, such as rectangular or square panes, as well as wafers of 200 mm, 300 mm, or other diameters.

[0048]

[0065] A device layer can then be deposited on the processing surface. The device layer can be a device layer as described with reference to Figures 1A-1D and 2A-2D. Furthermore, the device layer can be one of multiple device layers that can act in concert to form one or more features or components, such as components of a 3D NAND device.

[0049]

[0066] In operation 502, a first nanocrystalline diamond layer is deposited on a substrate or, in some embodiments, on a device layer. The first nanocrystalline diamond layer may have an average grain size of less than 6 nm. In one example, the first nanocrystalline diamond layer has an average grain size between 2 nm and 5 nm. A small grain size, such as less than 6 nm, allows for better control of adhesion between a hard mask layer, such as a nanocrystalline diamond layer, and an underlayer, allowing for a smaller size for the hard mask layer. Random placement of larger grains during deposition increases the number of non-contact spaces between the hard mask layer and the underlayer. Non-contact spaces are spaces between the hard mask layer and the underlayer where the hard mask layer does not directly contact the underlayer due to the shape and size of the grains in the hard mask layer and the roughness of the underlayer itself. Larger non-contact spaces reduce layer adhesion and reduce thermal transfer between the hard mask and the underlayer. The size of the non-contact spaces is reduced by smaller grains. This is because smaller grains can be more closely packed than larger grains when deposited as part of a layer. Additionally, the smaller grain size allows the layer to be thinner than a layer with a larger grain size while still maintaining good contact with the underlying layer.

[0050]

[0067] Deposition of the first nanocrystalline diamond layer in operation 502 may begin by supplying a deposition gas at a first pressure to a CVD process chamber having a plasma source (e.g., remote, microwave, CCP, or ICP). The deposition gas includes a carbon-containing precursor and a hydrogen-containing gas. In one or more embodiments, the carbon-containing precursor is an alkane precursor. The alkane precursor may be a saturated unbranched hydrocarbon, such as methane, ethane, propane, and combinations thereof. Other alkane precursors include n-butane, n-pentane, n-hexane, n-heptane, n-octane, and combinations thereof. The hydrogen-containing gas may include hydrogen (H), water (H0), ammonia (NH), or other hydrogen-containing molecules.

[0051]

[0068] Deposition gases are then supplied to the CVD process chamber. The deposition gases may be mixed either in the chamber or before entering the chamber. The deposition gases are supplied at a relatively high pressure, such as greater than 5 Torr. In one embodiment, the deposition gases are supplied at about 10 Torr to 100 Torr, for example, about 50 Torr.

[0052]

[0069] The deposition gas can then be activated to produce an activated deposition gas. The deposition gas can be activated by generating a plasma using a power source. Any power source capable of activating the gas into reactive species and maintaining a plasma of the reactive species may be used. For example, radio frequency (RF), direct current (DC), or microwave (MW)-based power discharge techniques may be used. The power source is applied to a CVD process chamber having a plasma source (e.g., remote, microwave, CCP, or ICP) to generate source plasma power, which creates and maintains a plasma of the deposition gas. In embodiments using RF power for the source plasma power, the source plasma power may be supplied at a frequency of about 2 MHz to about 170 MHz and at a power level between 500 W and 12,000 W. Other embodiments include supplying the source plasma power at about 2000 W to about 12,000 W. The applied power can be adjusted depending on the size of the substrate being processed. In one or more embodiments, the microwave plasma is applied as a continuous wave at a power ranging from about 2 to about 12 kilowatts (kW).

[0053]

[0070] Based on the high pressure in the CVD chamber, as well as other factors, radical generation is maximized while ionized species generation is minimized. Without intending to be bound by theory, it is believed that the nanocrystalline diamond layer should be primarily sp3-bonded rather than sp2-bonded. Furthermore, it is believed that more sp3 bonds can be achieved by increasing the number of radical species relative to ionized species during layer deposition. Ionized species are more energetic and may require more room to move than radicals. Increasing pressure reduces electron energy but increases the likelihood of collisions with other molecules. The decrease in electron energy and the increase in the number of collisions favor radical generation over ion generation.

[0054]

[0071] Once activated, the activated deposition gas is then supplied through a second space having a second pressure. The second space may be a second chamber or another enclosed area between the process space and a CVD chamber having a plasma source. In one embodiment, the second space is a connection between a CVD chamber having a plasma source and the process space.

[0055]

[0072] The second pressure is less than the first pressure. The transfer from the remote plasma chamber to the second space, based on either a flow rate, a change in overall volume, or a combination thereof, results in a reduced pressure of the activated deposition gas in the second space. The pressure is reduced to allow for better deposition from radical species while reducing collisions of ionized species with the deposition layer. In one embodiment, the second pressure is between about 0.1 Torr and about 5 Torr. In one or more embodiments, the second pressure is in the range of about 0.1 Torr to about 1 Torr.

[0056]

[0073] In one or more embodiments, an activated deposition gas comprising methane (CH4) / carbon dioxide (CO2) at a flow rate ranging from about 2 sccm to about 10 sccm is then supplied to the substrate in the process space of the process chamber. The substrate may be of any composition, such as a crystalline silicon substrate. The substrate may include one or more features, such as vias or interconnects. The substrate may be supported on a substrate support. The substrate support may be maintained at a particular temperature range. In one embodiment, the substrate support is maintained at a temperature range between about 500° C. and about 650° C.

[0057]

[0074] As shown in FIG. 3A, the substrate 302 can be preseeded for deposition of the nanocrystal layer. In one embodiment, the substrate 302 is immersed or otherwise coated in a seeding solution to form suspended nanodiamonds 304 on the substrate 302. The seeding solution can be an ethanol-based suspension of nanodiamonds. The substrate 302 can be immersed in the suspension during ultrasonic treatment, which causes some of the suspended nanodiamonds 304 to adhere to the surface of the substrate 302. Other preseeding techniques can be used without departing from the embodiments described herein.

[0058]

[0075] Referring to Figure 3B, a first nanocrystalline diamond layer 306 is then deposited on the surface of the substrate 302. Radicals from the previously generated activated deposition gas impinge on the substrate surface to form the first nanocrystalline diamond layer 306. It is believed that low pressure is beneficial for forming sp3 bonds in the first nanocrystalline diamond layer 306 from remotely generated radicals. Higher pressure in the CVD plasma chamber allows for preferential radical generation, while lower pressure in the process space allows for more uniform deposition from previously generated radicals.

[0059]

[0076] Once the first nanocrystalline diamond layer 306 is deposited, a hydrogen-containing gas is supplied to the CVD plasma chamber. The hydrogen-containing gas can be supplied at a separate time, or the gas flow from the previous step can be maintained. No alkane precursor is present in this section. The hydrogen-containing gas can be supplied with an inert gas or as part of a combination of multiple hydrogen-containing gases. In one or more embodiments, hydrogen (H2) gas is supplied at a flow rate ranging from about 90 sccm to about 96 sccm.

[0060]

[0077] The hydrogen-containing gas is then activated to produce an activated hydrogen-containing gas, which can be converted into a plasma using the same pressure, temperature, power type, power range, and other parameters for generating the plasma as described with respect to producing the activated deposition gas.

[0061]

[0078] Once the activated hydrogen-containing gas is generated, it can be supplied to the substrate in the process space. The process space and the substrate may be maintained at the same pressure, temperature, and other parameters as described above. It is believed that during the deposition process, polymers may be generated on the surface of the deposited nanocrystalline diamond layer. The polymers may affect further deposition or otherwise degrade the performance of the deposited layer. By supplying the activated hydrogen-containing gas to the deposited layer, the polymers are volatilized and then removed from the chamber, so that they do not affect the subsequent deposition process.

[0062]

[0079] The above components can then be repeated to deposit a second nanocrystalline diamond layer 308 having a lower roughness than the first nanocrystalline diamond layer 306. In operation 504, the second nanocrystalline diamond layer 308 is deposited on the first nanocrystalline diamond layer. The second nanocrystalline diamond layer may have an average grain size of less than 6 nm. In one example, the second nanocrystalline diamond layer has an average grain size of between 2 nm and 5 nm. A small grain size, such as less than 6 nm, allows for better control of adhesion between a hard mask layer, such as the second nanocrystalline diamond layer, and an underlayer, allowing for a smaller size for the hard mask layer. Random placement of larger grain sizes during deposition increases the number of non-contact spaces between the hard mask layer and the underlayer. A non-contact space is a space between the hard mask layer and the underlayer where the hard mask layer does not directly contact the underlayer due to the shape and size of the grains in the hard mask layer and the roughness of the underlayer itself. Larger non-contact spaces reduce the adhesion of the layer and reduce thermal transfer between the hard mask and the underlying layer. The size of the non-contact spaces is reduced by smaller grains because smaller grains can be packed more closely together than larger grains when deposited as part of a layer. Furthermore, the smaller grain size allows the layer to be thinner than a layer with a larger grain size while still maintaining good contact with the underlying layer.

[0063]

[0080] Deposition of the second nanocrystalline diamond layer in operation 504 may begin by supplying a deposition gas to the CVD plasma chamber at a first pressure. The deposition gas includes a carbon-containing precursor and a hydrogen-containing gas. In one or more embodiments, the carbon-containing precursor is an alkane precursor. The alkane precursor may be a saturated unbranched hydrocarbon, such as methane, ethane, propane, and combinations thereof. Other alkane precursors include n-butane, n-pentane, n-hexane, n-heptane, n-octane, and combinations thereof. The hydrogen-containing gas may include hydrogen (H), water (H2O), ammonia (NH3), or other hydrogen-containing molecules. The deposition gas may further include an inert gas. The inert gas may be a noble gas, such as argon (Ar).

[0064]

[0081] Deposition gases are then supplied to the CVD plasma chamber. The deposition gases may be mixed either in the chamber or before entering the chamber. The deposition gases are supplied at a relatively high pressure, such as greater than 5 Torr. In one embodiment, the deposition gases are supplied at about 10 Torr to 100 Torr, for example, about 50 Torr.

[0065]

[0082] The deposition gas can then be activated to produce an activated deposition gas. The deposition gas can be activated by generating a plasma using a power source. Any power source capable of activating the gas into reactive species and maintaining a plasma of the reactive species can be used. For example, radio frequency (RF), direct current (DC), or microwave (MW)-based power discharge techniques can be used. The power source generates a source plasma power that is applied to the CVD plasma chamber to generate and maintain a plasma of the deposition gas. In embodiments using RF power for the source plasma power, the source plasma power can be supplied at a frequency of about 2 MHz to about 170 MHz and at a power level between 500 W and 12,000 W. Other embodiments include supplying the source plasma power at about 2000 W to about 12,000 W. The applied power can be adjusted depending on the size of the substrate being processed.

[0066]

[0083] Based on the high pressure in the remote plasma chamber, as well as other factors, the generation of ionized species is minimized and the generation of radicals is maximized. Without intending to be bound by theory, it is believed that the nanocrystalline diamond layer should be primarily sp3-bonded rather than sp2-bonded. Furthermore, it is believed that more sp3 bonds can be achieved by increasing the number of radical species relative to ionized species during layer deposition. Ionized species are more energetic and may require more room to move than radicals. By increasing the pressure, the electron energy decreases, but the probability of collisions with other molecules increases. The decrease in electron energy and the increase in the number of collisions favor radical generation over ion generation.

[0067]

[0084] Once activated, the activated deposition gas, comprising methane (CH4) / carbon dioxide (CO2) / argon (Ar) at a flow rate ranging from 2 to 10 / 2 to 10 / 2 to 90 sccm, is then supplied through the second volume having a second pressure. The second volume can be a second chamber or another enclosed area between the process volume and the CVD plasma chamber. In one embodiment, the second volume is a connection between the CVD plasma chamber and the process volume.

[0068]

[0085] The second pressure is less than the first pressure. The transfer from the CVD plasma chamber to the second space, based on a flow rate, a change in overall volume, or a combination thereof, results in a reduced pressure of the activated deposition gas in the second space. The pressure is reduced to enable better deposition from radical species while reducing collisions of ionized species with the deposition layer. In one embodiment, the second pressure is between about 0.1 Torr and about 5 Torr. In one or more embodiments, the second pressure is in the range of about 0.1 Torr to about 1 Torr.

[0069]

[0086] An activated deposition gas, a mixture of methane (CH4), carbon dioxide (CO2), and argon (Ar), is then supplied to the substrate within the process space of the process chamber at flow rates ranging from about 2 to 10 / 2 to 10 / 2 to 90 sccm, respectively. In one embodiment, the substrate support is maintained at a temperature range between about 500°C and about 650°C.

[0070]

[0087] A second nanocrystalline diamond layer 308 is then deposited on the surface of the first nanocrystalline diamond layer 306. Radicals from the previously generated activated deposition gas impinge on the surface to form the second nanocrystalline diamond layer 308. Low pressure is believed to be beneficial for forming sp3 bonds in the second nanocrystalline diamond layer 308 from the remotely generated radicals. Higher pressure in the remote plasma source allows for preferential radical generation, while lower pressure in the process space allows for more uniform deposition from the previously generated radicals. The second nanocrystalline diamond layer 308 has a smooth surface with a roughness (AFM) of less than about 15 nm.

[0071]

[0088] Once the nanocrystalline diamond layer is deposited, a hydrogen-containing gas is supplied to the remote plasma chamber. The hydrogen-containing gas can be supplied at a separate time, or the gas flow from the previous step can be maintained. No alkane precursor is present in this section. The hydrogen-containing gas can be supplied together with an inert gas or as part of a combination of multiple hydrogen-containing gases. In one or more embodiments, hydrogen (H2) gas is supplied at a flow rate of about 1 sccm to about 94 sccm, including in the range of about 15 sccm to about 45 sccm.

[0072]

[0089] The hydrogen-containing gas is then activated to produce an activated hydrogen-containing gas, which can be converted into a plasma using the same pressure, temperature, power type, power range, and other parameters for generating the plasma as described with respect to producing the activated deposition gas.

[0073]

[0090] Once the activated hydrogen-containing gas is generated, it may be supplied to the substrate in the process space. The process space and the substrate may be maintained at the same pressure, temperature, and other parameters as described above. It is believed that during the deposition process, polymers may be generated on the surface of the deposited nanocrystalline diamond layer. The polymers may affect further deposition or otherwise degrade the performance of the deposited layer. By supplying the activated hydrogen-containing gas to the deposited layer, the polymers are volatilized and then removed from the chamber, so that they do not affect the subsequent deposition process.

[0074]

[0091] At decision point 506, it is determined whether the nanocrystalline hard mask 308 has achieved the predetermined roughness and thickness. Each deposition cycle produces a thickness of between about 20 Å and about 200 Å, for example about 100 Å. By repeating the above steps, the previous layer acts as a seed layer for the next deposition, and the entire desired thickness can be deposited. In one embodiment, the nanocrystalline diamond stack is deposited to a thickness of 1 μm.

[0075]

[0092] At decision point 506, if the nanocrystalline diamond stack is too rough or not thick enough, the cycle returns to operations 502 and 504 for a further deposition step.

[0076]

[0093] At decision point 506, if the nanocrystalline diamond stack has achieved the desired roughness and thickness, processing continues. In operation 508, the nanocrystalline diamond layer may then optionally be patterned and etched. Patterning may include depositing a photoresist 112, 212 over the nanocrystalline diamond layer. The photoresist 112, 212 is then exposed to radiation of an appropriate wavelength to form a pattern of openings / apertures 111, 211. The pattern is then etched into both the photoresist 112, 212 and then into the nanocrystalline diamond layer.

[0077]

[0094] In operation 510, the device may then be etched to form features or channels. The device may then be etched according to the pattern formed in the nanocrystalline diamond layer. The device is etched with an etchant that is selective to the device layers 104, 106, 204, 206 that overlie the nanocrystalline diamond layers 108, 208. The device layers are etched using chemistries and techniques well known in the art. In one embodiment, the etchant is a chlorine-containing etchant.

[0078]

[0095] In operation 512, the nanocrystalline diamond layer may then be removed from the surface of the device. The nanocrystalline diamond layer may be ashed from the surface of the device layer using, for example, a plasma ashing process. The plasma ashing process may include activating an oxygen-containing gas, such as O2. The ashing rate when using O2 is about 900 Å / min or greater. The nanocrystalline diamond layer may be ashed using a high aspect ratio etching system.

[0079]

[0096] 4A-4D show cross-sectional views of a device 400 being processed according to a method of one or more embodiments. FIG. 6 shows a process flow diagram of a method 600 according to one or more embodiments. In some embodiments, a substrate is provided for processing prior to operation 602. As used in this context, the term "provided" means that the substrate is placed in a location or environment for further processing. In one or more embodiments, the substrate is maintained at a temperature in the range of about 500° C. to about 650° C.

[0080]

[0097] A device layer can then be deposited on the processing surface. The device layer can be a device layer as described with reference to Figures 1A-1D and 2A-2D. Furthermore, the device layer can be one of multiple device layers. The device layers can act in concert to form one or more features or components, such as components of a 3D NAND device.

[0081]

[0098] In operation 602, a nanocrystalline diamond layer is deposited on the substrate, or in some embodiments, on the device layer. The nanocrystalline diamond layer may have an average grain size of less than 6 nm. In one example, the nanocrystalline diamond layer has an average grain size between 2 nm and 5 nm. A small grain size, such as less than 6 nm, allows for better control of adhesion between a hard mask layer, such as a nanocrystalline diamond layer, and an underlayer, allowing for a smaller size for the hard mask layer. Random placement of larger grains during deposition increases the number of non-contact spaces between the hard mask layer and the underlayer. Non-contact spaces are spaces between the hard mask layer and the underlayer where the hard mask layer does not directly contact the underlayer due to the shape and size of the grains in the hard mask layer and the roughness of the underlayer itself. Larger non-contact spaces reduce the adhesion of the layer and reduce thermal transfer between the hard mask and the underlayer. The size of the non-contact spaces is reduced by smaller grains because smaller grains can be packed more densely than larger grains when deposited as part of a layer. Additionally, the small grain size allows the layer to be thinner than larger grained layers while still maintaining good contact with the underlying layer.

[0082]

[0099] Deposition of the nanocrystalline diamond layer in operation 602 may begin by supplying a deposition gas to a CVD chamber (having a plasma source) at a first pressure. The deposition gas includes a carbon-containing precursor and a hydrogen-containing gas. In one or more embodiments, the carbon-containing precursor is an alkane precursor. The alkane precursor may be a saturated unbranched hydrocarbon, such as methane, ethane, propane, and combinations thereof. Other alkane precursors include n-butane, n-pentane, n-hexane, n-heptane, n-octane, and combinations thereof. The hydrogen-containing gas may include hydrogen (H), water (H0), ammonia (NH), or other hydrogen-containing molecules.

[0083]

[0100] The deposition gases are then supplied to a CVD chamber (having a plasma source). The deposition gases may be mixed either in the chamber or before entering the chamber. The deposition gases are supplied at a relatively high pressure, such as greater than 5 Torr. In one embodiment, the deposition gases are supplied at about 10 Torr to 100 Torr, for example, about 50 Torr.

[0084]

[0101] The deposition gas can then be activated to produce an activated deposition gas. The deposition gas can be activated by generating a plasma using a power source. Any power source capable of activating the gas into reactive species and maintaining a plasma of the reactive species may be used. For example, radio frequency (RF), direct current (DC), or microwave (MW)-based power discharge techniques may be used. The power source generates a source plasma power that is applied to the CVD chamber (having a plasma source) to generate and maintain a plasma of the deposition gas. In embodiments using RF power for the source plasma power, the source plasma power may be supplied at a frequency of about 2 MHz to about 170 MHz and at a power level between 500 W and 12,000 W. Other embodiments include supplying the source plasma power at about 2000 W to about 12,000 W. The applied power can be adjusted depending on the size of the substrate being processed. In one or more embodiments, the microwave plasma is applied as a continuous wave at a power ranging from about 2 kilowatts (kW) to about 12 kilowatts (kW).

[0085]

[0102] Based on the high pressure in the CVD chamber (containing the plasma source), as well as other factors, the generation of ionized species is minimized and the generation of radicals is maximized. Without intending to be bound by theory, it is believed that the nanocrystalline diamond layer should be primarily sp3-bonded rather than sp2-bonded. Furthermore, it is believed that more sp3 bonds can be achieved by increasing the number of radical species relative to ionized species during layer deposition. Ionized species are more energetic and may require more room to move than radicals. By increasing the pressure, the electron energy decreases, but the probability of collisions with other molecules increases. The decrease in electron energy and the increase in the number of collisions favor radical generation over ion generation.

[0086]

[0103] Once activated, the activated deposition gas is then supplied through a second volume having a second pressure. The second volume may be a second chamber or another enclosed area between the process volume and the remote plasma chamber. In one embodiment, the second volume is a connection between the remote plasma chamber and the process volume.

[0087]

[0104] The second pressure is less than the first pressure. The transfer from the remote plasma chamber to the second space, based on a flow rate, a change in overall volume, or a combination thereof, results in a reduced pressure of the activated deposition gas in the second space. The pressure is reduced to allow for better deposition from radical species while reducing collisions of ionized species with the deposition layer. In one embodiment, the second pressure is between about 0.1 Torr and about 5 Torr. In one or more embodiments, the second pressure is in the range of about 0.1 Torr to about 1 Torr.

[0088]

[0105] An activated deposition gas comprising methane (CH4) / carbon dioxide (CO2) at a flow rate ranging from 2 sccm to 10 sccm is then supplied to the substrate within the processing space of the processing chamber. The substrate may be of any composition, such as a crystalline silicon substrate. The substrate may include one or more features, such as vias or interconnects. The substrate may be supported on a substrate support. The substrate support may be maintained at a particular temperature range. In one embodiment, the substrate support is maintained at a temperature range between about 500° C. and about 650° C.

[0089]

[0106] As shown in FIG. 4A, the substrate 402 can be pre-seeded for deposition of the nanocrystal layer. In one embodiment, the substrate 402 is immersed or otherwise coated in a seeding solution to form suspended nanodiamonds 404 on the substrate 402. The seeding solution can be an ethanol-based suspension of nanodiamonds. The substrate 402 is immersed in the suspension during ultrasonic treatment, which causes some of the suspended nanodiamonds 404 to adhere to the surface of the substrate 402. Other pre-seeding techniques can be used without departing from the embodiments described herein.

[0090]

[0107] Referring to Figure 4B, a nanocrystalline diamond layer 406 is then deposited on the surface of the substrate 402. Radicals from the previously generated activated deposition gas impinge on the substrate surface to form the nanocrystalline diamond layer 406. It is believed that low pressure is beneficial for forming sp3 bonds in the first nanocrystalline diamond layer 406 from the remotely generated radicals. A higher pressure in the remote plasma source allows for preferential radical generation, while a lower pressure in the process space allows for more uniform deposition from the previously generated radicals.

[0091]

[0108] Once the nanocrystalline diamond layer 406 is deposited, a hydrogen-containing gas is supplied to the CVD chamber (containing the plasma source). The hydrogen-containing gas can be supplied at a separate time, or the gas flow from the previous step can be maintained. No alkane precursor is present in this section. The hydrogen-containing gas can be supplied together with an inert gas or as part of a combination of multiple hydrogen-containing gases. In one or more embodiments, hydrogen (H2) gas is supplied at a flow rate ranging from 90 sccm to 96 sccm.

[0092]

[0109] The hydrogen-containing gas is then activated to produce an activated hydrogen-containing gas, which can be converted into a plasma using the same pressure, temperature, power type, power range, and other parameters for generating the plasma as described with respect to producing the activated deposition gas.

[0093]

[0110] Once the activated hydrogen-containing gas is generated, it can be supplied to the substrate in the process space. The process space and the substrate may be maintained at the same pressure, temperature, and other parameters as described above. It is believed that during the deposition process, polymers may be generated on the surface of the deposited nanocrystalline diamond layer. The polymers may affect further deposition or otherwise degrade the performance of the deposited layer. By supplying the activated hydrogen-containing gas to the deposited layer, the polymers are volatilized and then removed from the chamber, so that they do not affect the subsequent deposition process.

[0094]

[0111] 4C and 6, in operation 604, the nanocrystalline diamond layer 406 is exposed to an inert gas plasma to form a smooth surface nanocrystalline diamond layer 408. In one or more embodiments, the gas flow comprises an inert gas selected from one or more of helium (He), neon (Ne), and argon (Ar). In one or more specific embodiments, the inert gas plasma comprises argon (Ar) supplied at a flow rate ranging from about 50 sccm to about 200 sccm, pulsed by 10-90% with microwave power ranging from about 2 kW to about 12 kW, at a pressure ranging from about 0.1 Torr to about 1 Torr, and at a temperature ranging from about 500°C to about 650°C.

[0095]

[0112] An inert gas is then supplied to the remote plasma chamber. The inert gas is supplied at a relatively high pressure, such as greater than 5 Torr. In one embodiment, the inert gas is supplied at between about 10 Torr and 100 Torr, for example, about 50 Torr.

[0096]

[0113] The inert gas can then be activated to produce an activated inert gas. The inert gas can be activated by generating a plasma using a power source. Any power source capable of activating the gas into reactive species and maintaining a plasma of the reactive species may be used. For example, radio frequency (RF), direct current (DC), or microwave (MW)-based power discharge techniques may be used. The power source generates a source plasma power that is applied to the CVD chamber (having a plasma source) to generate and maintain a plasma of the inert gas. In embodiments using RF power as the source plasma power, the source plasma power may be supplied at a frequency of about 2 MHz to about 170 MHz and at a power level between 500 W and 12,000 W. Other embodiments include supplying the source plasma power at about 2000 W to about 12,000 W. The applied power can be adjusted depending on the size of the substrate being processed.

[0097]

[0114] Based on the high pressure in the CVD chamber (with the plasma source), as well as other factors, the generation of ionized species is minimized while the generation of radicals is maximized, resulting in smoothing of the surface of nanocrystalline diamond layer 406 to form smoothed nanocrystalline diamond layer 408.

[0098]

[0115] Once activated, the activated inert gas, including argon (Ar) at a flow rate ranging from about 50 sccm to about 200 sccm, is then supplied through the second volume having a second pressure. The second volume may be a second chamber or another enclosed area between the process volume and the remote plasma chamber. In one embodiment, the second volume is a connection between the remote plasma chamber and the process volume.

[0099]

[0116] The second pressure is less than the first pressure. The transfer from the remote plasma chamber to the second space, based on a flow rate, a change in overall volume, or a combination thereof, results in a reduced pressure of the activated deposition gas in the second space. The pressure is reduced to allow for better deposition from radical species while reducing collisions of ionized species with the deposition layer. In one embodiment, the second pressure is between about 0.1 Torr and about 5 Torr. In one or more embodiments, the second pressure is in the range of about 0.1 Torr to about 1 Torr.

[0100]

[0117] The activated inert gas is then supplied to the nanocrystalline diamond layer 406 in the process space of the process chamber at a flow rate ranging from about 50 sccm to about 200 sccm. In one embodiment, the substrate support is maintained at a temperature range between about 500°C and about 650°C.

[0101]

[0118] The smooth nanocrystalline diamond layer 408 has a smooth surface with a roughness (AFM) of less than about 15 nm.

[0102]

[0119] At decision point 606, it is determined whether the smooth nanocrystalline hard mask 408 has achieved the predetermined roughness and thickness. Each deposition cycle produces a thickness of between about 20 Å and about 200 Å, for example about 100 Å. By repeating the above steps, the previous layer acts as a seed layer for the next deposition, and the entire desired thickness can be deposited. In one embodiment, the nanocrystalline diamond stack is deposited to a thickness of 1 μm.

[0103]

[0120] If, at decision point 606, the nanocrystalline diamond stacks are too rough or not thick enough, the cycle returns to operations 602 and 604 for further deposition and smoothing steps, resulting in thick and smooth nanocrystalline diamond stacks 410 (see Figure 4D).

[0104]

[0121] At decision point 606, if the nanocrystalline diamond stack has achieved the desired roughness and thickness, processing continues. In operation 608, the nanocrystalline diamond layer may then optionally be patterned and etched. Patterning may include depositing a photoresist 112, 212 over the nanocrystalline diamond layer. The photoresist 112, 212 is then exposed to radiation of an appropriate wavelength to form a pattern of openings / apertures 111, 211. The pattern is then etched into both the photoresist 112, 212 and then the nanocrystalline diamond layer.

[0105]

[0122] In operation 610, the device may then be etched to form features or channels. The device may then be etched according to the pattern formed in the nanocrystalline diamond layer. The device is etched with an etchant selective to the device layers 104, 106, 204, 206 that overlie the nanocrystalline diamond layers 108, 208. The device layers are etched using chemistries and techniques well known in the art. In one embodiment, the etchant is a chlorine-containing etchant.

[0106]

[0123] In operation 612, the nanocrystalline diamond layer may then be removed from the surface of the device. The nanocrystalline diamond layer may be ashed from the surface of the device layer using, for example, a plasma ashing process. The plasma ashing process may include activating an oxygen-containing gas, such as O2. The ashing rate when using O2 is about 900 Å / min or greater. The nanocrystalline diamond layer may be ashed using a high aspect ratio etching system.

[0107]

[0124] In the foregoing specification, embodiments of the invention have been described with reference to certain exemplary embodiments thereof. It will be apparent that various modifications can be made to the invention without departing from the broader spirit and scope of the embodiments of the invention as set forth in the following claims. Accordingly, the specification and drawings should be regarded as illustrative rather than restrictive.

[0108]

[0125] Throughout this specification, references to "one embodiment," "certain embodiment," "one or more embodiments," or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, the appearances of phrases such as "in one or more embodiments," "in a particular embodiment," "in one embodiment," or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0109]

[0126] Although the disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed method and apparatus without departing from the spirit and scope of the disclosure. Therefore, it is intended that the present invention cover modifications and variations that come within the scope of the appended claims and their equivalents.

Claims

1. depositing a first nanocrystalline diamond layer on a substrate, the first nanocrystalline diamond layer having a first thickness, a first roughness, a first hardness, and a first elastic modulus; depositing a second nanocrystalline diamond layer on the first nanocrystalline diamond layer, the second nanocrystalline diamond layer having a second thickness and a second roughness; The method of processing, wherein the first thickness is greater than the second thickness and the second roughness is less than the first roughness.

2. 10. The processing method of claim 1, wherein depositing the first nanocrystalline diamond layer comprises generating a deposition gas comprising a carbon-containing gas and carbon dioxide and activating the deposition gas to generate a plasma.

3. 10. The method of claim 1, further comprising depositing a seed layer on the substrate before depositing the first nanocrystalline diamond layer.

4. The method of claim 3 , wherein the seed layer comprises nanocrystalline diamond.

5. 3. The method of claim 2, further comprising exposing the substrate to a hydrogen plasma to form the first nanocrystalline diamond layer.

6. 10. The process of claim 1, wherein depositing the second nanocrystalline diamond layer comprises generating a deposition gas comprising a carbon-containing gas, carbon dioxide, and an inert gas and activating the deposition gas to generate a plasma.

7. 7. The method of claim 6, further comprising exposing the first nanocrystalline diamond layer to a hydrogen plasma to form the second nanocrystalline diamond layer.

8. 10. The method of claim 1, wherein the first thickness ranges from about 250 nm to about 650 nm.

9. 10. The method of claim 1, wherein the second thickness ranges from about 5 nm to about 200 nm.

10. The method of claim 1 , wherein the first roughness is greater than about 25 nm.

11. The method of claim 1 , wherein the second roughness is less than about 15 nm.

12. depositing a first nanocrystalline diamond layer on the seed layer, the first nanocrystalline diamond layer having a first thickness, a first roughness, a first hardness, and a first elastic modulus; 1. A method of treating comprising exposing the first nanocrystalline diamond layer to an inert gas plasma to form a smooth nanocrystalline diamond layer.

13. 13. The processing method of claim 12, wherein depositing the first nanocrystalline diamond layer comprises generating a deposition gas comprising a carbon-containing gas and carbon dioxide and activating the deposition gas to generate a plasma.

14. 13. The method of claim 12, further comprising depositing a seed layer on the substrate before depositing the first nanocrystalline diamond layer.

15. 15. The method of claim 14, wherein the seed layer comprises nanocrystalline diamond.

16. 14. The method of claim 13, further comprising exposing the substrate to a hydrogen plasma to form the first nanocrystalline diamond layer.

17. 13. The method of claim 12, wherein the inert gas plasma comprises one or more of helium (He), neon (Ne), and argon (Ar).

18. 13. The method of claim 12, wherein the first roughness is greater than about 25 nm.

19. 13. The method of claim 12, wherein the smooth nanocrystalline diamond layer has a second roughness of less than about 15 nm.

20. a memory stack comprising a plurality of alternating layers of a first material and a second material on a substrate; a nanocrystalline diamond layer on the memory stack, the nanocrystalline diamond layer having a roughness of less than about 15 nm; and A memory device comprising a memory channel extending from a top surface of the memory stack to the substrate.

Images