Systems and methods for forming UV-cured low-k dielectric films

Abstract

A semiconductor processing method for forming a UV-treated low-κ dielectric film is described. The method may include flowing deposition precursors into a substrate processing region of a semiconductor processing chamber. The deposition precursors may include silicon- and carbon-containing precursors. The method may further include generating a deposition plasma from the deposition precursors in the substrate processing region and depositing a silicon- and carbon-containing material on the substrate from plasma effluents of the deposition plasma. The as-deposited silicon- and carbon-containing material may be characterized by about 5% or more hydrocarbon groups. The method may still further include exposing the deposited silicon- and carbon-containing material to ultraviolet light. The exposed silicon- and carbon-containing material may be characterized by about 2% or less hydrocarbon groups.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. patent application Ser. No. 17 / 063,358, filed October 5, 2020, entitled "SYSTEMS AND METHODS FOR FORMING UV-CURED LOW-K DIELECTRIC FILMS," the entire contents of which are incorporated herein by reference.

[0002] Technical Field

[0002] The present technology relates to deposition processes and chambers. More particularly, this application relates to methods for producing low dielectric constant films using UV processing. [Background technology]

[0003]

[0003] Integrated circuits are realized by processes that create intricately patterned layers of material on a substrate surface. Fabricating patterned materials on a substrate requires controlled methods for forming and removing materials. The properties of the materials can affect how the device operates and can also affect how films are removed relative to each other. Plasma-enhanced deposition can produce films with specific properties. Many of the films formed require additional processing to adjust or enhance the material properties of the film to provide the appropriate properties.

[0004]

[0004] Therefore, there is a need for improved systems and methods that can be used to produce high quality devices and structures. The above needs and others are addressed by the present technique. Summary of the Invention

[0005]

[0005] Embodiments of the present technology include semiconductor processing methods for forming dielectric films having a low dielectric constant (i.e., low-κ) compared to silicon dioxide (κ=3.9). Dielectric film embodiments include carbon-containing silicon oxide films having a dielectric constant (i.e., κ value) of about 2.6 or less. In processing method embodiments, these UV-treated low-κ carbon-containing dielectric films can be formed as electrically insulating dielectric layers between metal lines and contacts in back-end-of-line (BEOL) semiconductor manufacturing processes. The low κ value of the carbon-containing silicon oxide films can reduce RC delays in signal propagation, crosstalk noise, and power losses in metal lines and contacts separated by the low-κ film.

[0006] An embodiment of a semiconductor processing method may include flowing deposition precursors into a substrate processing region of a semiconductor processing chamber. The deposition precursors may include silicon- and carbon-containing precursors. The method may further include generating a deposition plasma from the deposition precursors in the substrate processing region. A silicon- and carbon-containing material may be deposited on the substrate from plasma effluents of the deposition plasma. The as-deposited silicon- and carbon-containing material may be characterized by about 5% or more hydrocarbon groups, as expressed by FTIR peak area ratios of the material's constituent elements. The method may include exposing the deposited silicon- and carbon-containing material to ultraviolet light. The exposed silicon- and carbon-containing material may be characterized by about 2% or less hydrocarbon groups.

[0007] In additional embodiments, the hydrocarbon group is —C x H y where x is an integer greater than or equal to about 1 and y is an integer greater than or equal to about 2. In still further embodiments, the silicon-containing precursor may comprise a compound represented by Formula 1: JPEG0007815229000001.jpg30170, where R1, R2, and R3 may comprise a C1-C6 alkyl group or a C1-C6 alkoxy group, and at least one of R1, R2, and R3 is an alkoxy group. In still further embodiments, the as-deposited silicon- and carbon-containing material may be characterized by a carbon content of about 20 at.% (atomic percent) or greater, and the exposed silicon- and carbon-containing material may be characterized by a carbon content of about 15 at.% or less. In still further embodiments, the exposed silicon- and carbon-containing material may be characterized by a methyl incorporation of greater than 2.5%, expressed as the FTIR peak area ratio of the material's constituent elements. In yet additional embodiments, the exposed silicon- and carbon-containing material may be characterized by a porosity of about 15 vol.% or greater. In yet additional embodiments, the exposed silicon- and carbon-containing material may be characterized by a dielectric constant (κ value) of about 2.6 or less. In further embodiments, the exposed silicon and carbon containing material may be characterized by a Young's modulus of about 10 GPa or greater, and in still further embodiments, the exposed silicon and carbon containing material may be characterized by a hardness of about 2 GPa or greater.

[0008]

[0008] Embodiments of the present technology may include additional methods for forming UV-cured low-κ dielectric films. Method embodiments may include flowing a deposition precursor into a substrate processing region of a semiconductor processing chamber. In embodiments, the deposition precursor may include a precursor containing silicon, carbon, and oxygen. Method embodiments may further include generating a deposition plasma from the deposition precursor in the substrate processing region. The semiconductor processing chamber may be characterized by a temperature of about 300°C or greater during generation of the deposition plasma and deposition of the plasma onto the substrate in the semiconductor processing chamber. The method may further include exposing the silicon-, carbon-, and oxygen-containing material as deposited to ultraviolet light. The exposed silicon-, carbon-, and oxygen-containing material may be characterized by a dielectric constant of about 2.6 or less.

[0009] In additional embodiments, the as-deposited silicon-, carbon-, and oxygen-containing material may be characterized by about 5% or more hydrocarbon groups, and the exposed silicon-, carbon-, and oxygen-containing material may be characterized by about 2% or less hydrocarbon groups. In yet additional embodiments, the as-deposited silicon-, carbon-, and oxygen-containing material may be characterized by about 4% or less methyl incorporation, and the exposed silicon-, carbon-, and oxygen-containing material may be characterized by about 3.5% or more methyl incorporation. In further embodiments, the silicon-, carbon-, and oxygen-containing precursor may include at least one vinyl group. In yet further embodiments, the as-deposited silicon-, carbon-, and oxygen-containing material may be characterized by a porosity of about 10 vol.% or less. In yet further embodiments, the exposed silicon-, carbon-, and oxygen-containing material may be characterized by a Young's modulus of about 10 GPa or greater, and may be further characterized by a hardness of about 2 GPa or greater.

[0010]

[0010] Embodiments of the present technology may include yet further methods for forming low-κ dielectric films. Method embodiments may include flowing a deposition precursor into a substrate processing region of a semiconductor processing chamber. The deposition precursor may include a silicon-, carbon-, and oxygen-containing precursor having at least one vinyl group. The method may further include depositing the silicon-, carbon-, and oxygen-containing material on a substrate in the semiconductor processing chamber. In some embodiments, the as-deposited silicon-, carbon-, and oxygen-containing material may be characterized by a porosity of about 10 vol.% or less. The as-deposited material on the substrate may be exposed to ultraviolet light, and the exposed silicon-, carbon-, and oxygen-containing material may be characterized by a porosity of about 15 vol.% or more.

[0011] In additional embodiments, the as-deposited silicon-, carbon-, and oxygen-containing material may be deposited from deposition plasma effluents formed from a deposition plasma generated by a deposition precursor. In yet additional embodiments, the exposed silicon-, carbon-, and oxygen-containing material may be characterized by about 0.1% or more Si-C-Si bonds, expressed as a ratio of the FTIR peak areas of the material's constituents. In further embodiments, the exposed silicon-, carbon-, and oxygen-containing material may be characterized by a Young's modulus of about 10 GPa or more and a hardness of about 2 GPa or more. In yet further embodiments, the exposed silicon-, carbon-, and oxygen-containing material may be characterized by about 3.5% or more methyl incorporation. In yet further embodiments, the exposed silicon-, carbon-, and oxygen-containing material may be characterized by a dielectric constant of about 2.6 or less.

[0012] Such techniques may offer numerous advantages over conventional processing methods. For example, the use of silicon-containing precursors containing organic moieties that increase the amount of hydrocarbon groups in the as-deposited material enhances the ability of UV processing to reduce the dielectric constant of the exposed material. UV light releases more weakly bonded hydrocarbon groups from the material than strongly bonded Si—C and Si—O—C carbons. The hydrocarbon groups released by UV light leave pores in the exposed low-κ material, further reducing the dielectric constant (κ value) of the material. In embodiments, the methods of the present invention further increase the amount of hydrocarbon groups in the as-deposited material by depositing at a lower substrate temperature than is typical for conventional deposition of low-κ materials. In embodiments, deposition may be performed at a temperature of about 300° C. or less to deposit a low-κ material with more unreacted or partially reacted hydrocarbon groups remaining in the material. Subsequent exposure to UV light results in greater removal of hydrocarbon groups from the material, increasing the pore volume and reducing the dielectric constant (κ value). Because UV treatment selectively removes hydrocarbon groups over other carbon groups in the low-κ material, a significant amount of cross-linked carbon remains in the exposed material, maintaining mechanical stability despite increased porosity. Thus, another advantage of the present technology is the formation of UV-treated carbon-containing low-κ films at low temperatures with increased porosity that does not reduce the film's mechanical stability. These and other embodiments, along with their many advantages and features, are described in more detail below and in the accompanying drawings.

[0013] A further understanding of the nature and advantages of the disclosed technology may be obtained by reference to the remainder of this specification and the drawings. [Brief explanation of the drawings]

[0014] [Figure 1] 1 illustrates a top view of an exemplary processing system in accordance with some embodiments of the present technique. [Figure 2]

[0015] 1 shows a schematic cross-sectional view of an exemplary plasma system in accordance with some embodiments of the present technique; [Figure 3]

[0016] 1 illustrates operations of an exemplary method of semiconductor processing in accordance with some embodiments of the present technique. DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0017] Some figures are included as schematics. It is understood that the figures are for illustrative purposes and should not be considered to scale unless expressly stated to be to scale. Furthermore, as schematics, the drawings are provided to aid in understanding and may not include all aspects or information compared to realistic depictions and may include exaggerated material for illustrative purposes.

[0016]

[0018] In the accompanying drawings, similar components and / or features may have the same reference numerals. Furthermore, various components of the same type may be distinguished according to the reference numeral, with a letter distinguishing between the similar components. When only a first reference numeral is used herein, the description is applicable to any one of the similar components having the same first reference numeral, regardless of the letter.

[0017]

[0019] During back-end-of-line (BEOL) semiconductor processing, low-κ films can serve multiple functions in the fabrication of metallization layers in integrated circuits. These functions can include the incorporation of electrically insulating low-κ films between conductive metal-containing structures such as interconnect lines, contact holes, and vias. They can also include the partial removal of low-κ films after the formation of metal structures. One common removal process in BEOL processing is chemical-mechanical polishing (CMP), which uses a combination of chemical etching and physical polishing to remove low-κ materials from the substrate surface.

[0018]

[0020] Low-κ films used in BEOL processing must have a low dielectric constant (κ value) compared to undoped silicon oxide and high mechanical stability to resist fracture during the formation of metal-containing structures and removal by CMP. Unfortunately, these qualities are often under strain in low-κ films made from UV-treated silicon, carbon, and oxygen-containing materials. UV treatment often increases the porosity of the film, and increased porosity can reduce the film's mechanical stability. Furthermore, increasing the carbon level in the film can decrease the κ value and reduce the film's mechanical stability. Reduced mechanical stability can be measured by films with low Young's modulus and low hardness, among other mechanical properties.

[0019]

[0021] One approach to addressing these issues is to replace the UV treatment operation with other types of processing. In some conventional embodiments, the UV treatment operation is eliminated by depositing low-κ films at elevated deposition temperatures, such as approximately 500°C or higher. Unfortunately, these high deposition temperatures can exceed the thermal budget of many semiconductor fabrication processes. Higher temperatures can also cause undesirable reactions in the low-κ materials being deposited, such as Si-H and oxygen groups reacting to form hydroxyl (-OH) groups in the as-deposited film. A relatively small amount of hydroxyl groups can significantly increase the dielectric constant of a low-κ film. Furthermore, in conventional methods, the UV treatment operation is replaced with a plasma treatment after deposition of the low-κ material. While plasma treatment can be performed at temperatures lower than high-temperature deposition, it is typically performed at temperatures higher than UV treatment, such as approximately 400°C or higher. These plasma treatment temperatures can strain the thermal budget of some semiconductor fabrication methods. Furthermore, conventional plasma treatment of low-κ carbon-containing films makes it very difficult to reduce the dielectric constant (κ value) below 3.0. In many semiconductor manufacturing processes, a dielectric constant of about 2.6 or less is desired for low-κ films.

[0020]

[0022] The present technology may overcome these challenges by including embodiments of semiconductor processing methods that form UV-treated low-κ films with good mechanical stability. In embodiments, these low-κ films may be characterized by a low dielectric constant (κ value) of about 2.6 or less. The low dielectric constant may be due in part to the high porosity of UV-treated films, about 15 vol.% or more. However, embodiments of the inventive methods maintain the mechanical stability of the films despite the high porosity. They may be characterized by a high Young's modulus of about 10 GPa or more and a high hardness of about 2 GPa or more.

[0021]

[0023] The present technology includes embodiments of semiconductor processing methods that deposit low-κ materials with increased amounts of weakly reactive hydrocarbon groups that can be selectively removed by UV treatment operations, relative to silicon and carbon bridged with silicon oxide groups, resulting in exposed low-κ materials with increased porosity, reduced dielectric constants, and better mechanical stability compared to conventional UV treatment operations on as-deposited low-κ materials with fewer hydrocarbon groups.

[0022]

[0024] While the remainder of the disclosure routinely identifies particular deposition processes utilizing 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 may occur in the described chambers. Thus, the present technology should not be considered limited to use with these specific deposition processes or chambers alone. This disclosure describes one possible system and chamber that may be used to perform a deposition process according to embodiments of the present technology before describing additional details according to embodiments of the present technology.

[0023]

[0025] 1 illustrates a top view of one embodiment of a processing system 100 for deposition, etch, bake, and UV treatment chambers, according to an embodiment. In the figure, a pair of front-opening unified pods 102 supply substrates of various sizes that are received by a robotic arm 104 and placed in a low-pressure holding area 106 before being placed in one of the substrate processing chambers 108a-108f positioned in tandem sections 109a-109c. A second robotic arm 110 may be used to transfer substrate wafers from the holding area 106 to and from the substrate processing chambers 108a-108f. Each substrate processing chamber 108a-f may be equipped to perform a number of substrate processing operations, including plasma-enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, etching, UV treatment, pre-cleaning, degassing, alignment, and annealing, ashing, and the like.

[0024]

[0026] The substrate processing chambers 108a-f may include one or more system components for depositing, annealing, UV treating, and / or etching a dielectric or other film on a substrate. In one configuration, two pairs of processing chambers (e.g., 108c-d and 108e-f) may be used to deposit a dielectric material on a substrate, and a third pair of processing chambers (e.g., 108a-b) may be used to etch the deposited dielectric. In another configuration, all three pairs of chambers, e.g., 108a-108f, may be configured to deposit an alternating stack of dielectric films on a substrate. Any one or more of the described processes may be performed in chambers separate from the fabrication system shown in different embodiments. It will be understood that additional configurations of deposition, etching, annealing, and UV treatment chambers for dielectric films are contemplated by system 100.

[0025]

[0027] 2 shows a schematic cross-sectional view of an exemplary plasma system 200 in accordance with some embodiments of the present technique. The plasma system 200 may illustrate a pair of processing chambers 108, which may be equipped in one or more of the tandem sections 109 described above and may include lid stack components in accordance with embodiments of the present technique, and may be further described below. The plasma system 200 may generally include a chamber body 202 having a sidewall 212, a bottom wall 216, and an interior sidewall 201 that define a pair of processing regions 220A and 220B. Each of the processing regions 220A-220B may be similarly configured and may include identical components.

[0026]

[0028] For example, processing region 220B (components of which may also be included in processing region 220A) may include a pedestal 228 disposed within the processing region through a passage 222 formed in the bottom wall 216 of the plasma system 200. The pedestal 228 may provide a heater adapted to support a substrate 229 on an exposed surface of the pedestal, such as a body portion. The pedestal 228 may include a heating element 232, e.g., a resistive heating element, that may heat and control the substrate temperature at a desired processing temperature. The pedestal 228 may also be heated by a remote heating element, such as a lamp assembly, or any other heating device.

[0027]

[0029] The body of the pedestal 228 may be coupled to the stem 226 by a flange 233. The stem 226 may electrically couple the pedestal 228 to a power output or power box 203. The power box 203 may include a driver system that controls the elevation and movement of the pedestal 228 within the processing region 220B. The stem 226 may also include a power interface for supplying power to the pedestal 228. The power box 203 may also include an interface for a power meter and a thermometer, such as a thermocouple interface. The stem 226 also includes a base assembly 238 adapted to removably couple to the power box 203. A circumferential ring 235 is shown above the power box 203. In some embodiments, the circumferential ring 235 may be a shoulder adapted as a mechanical stop or land configured to provide a mechanical interface between the base assembly 238 and the top surface of the power box 203.

[0028]

[0030] A rod 230 may be included through a passage 224 formed in the bottom wall 216 of the processing region 220B. The rod 230 may be utilized to position substrate lift pins 261 disposed through the body of the pedestal 228. The substrate lift pins 261 may selectively position the substrate 229 at a distance from the pedestal to facilitate exchange of the substrate 229 by a robot utilized to transfer substrates into and out of the processing region 220B through the substrate transfer port 260.

[0029]

[0031] The chamber lid 204 may be coupled to the top of the chamber body 202. The lid 204 may house one or more precursor delivery systems 208 coupled thereto. The precursor delivery system 208 may include a precursor inlet passage 240 that may deliver reactant and cleaning precursors into the processing region 220B through a dual channel showerhead 218. The dual channel showerhead 218 may include an annular base plate 248 having a shield plate 244 disposed intermediate a faceplate 246. A radio frequency (“RF”) source 265 may be coupled to the dual channel showerhead 218. The RF source 265 may power the dual channel showerhead 218 to facilitate generation of a plasma region between the faceplate 246 and the pedestal 228 of the dual channel showerhead 218. The dual channel showerhead 218 and / or faceplate 246 may include one or more openings that allow precursors to flow from the precursor delivery system 208 to the processing region 220A and / or 220B. In some embodiments, the opening may include at least one of a linear opening and a conical opening. In some embodiments, the RF source may be coupled to other portions of the chamber body 202, such as the pedestal 228, to facilitate plasma generation. A dielectric isolator 258 may be disposed between the lid 204 and the dual-channel showerhead 218 to prevent conduction of RF power to the lid 204. A shadow ring 206 may be disposed on the outer edge of the pedestal 228, and the shadow ring 206 engages with the pedestal 228.

[0030]

[0032] Optional cooling channels 247 may be formed in the annular base plate 248 of the precursor delivery system 208 to cool the annular base plate 248 during operation. A heat transfer fluid, such as water, ethylene glycol, gas, or the like, may be circulated through the cooling channels 247 so that the base plate 248 may be maintained at a predetermined temperature. A liner assembly 227 may be positioned in the processing region 220B in close proximity to the sidewalls 201, 212 of the chamber body 202 to prevent exposure of the sidewalls 201, 212 to the processing environment in the processing region 220B. The liner assembly 227 may include a circumferential pumping cavity 225 that may be coupled to a pumping system 264 configured to exhaust gases and byproducts from the processing region 220B and to control the pressure within the processing region 220B. A plurality of exhaust ports 231 may be formed in the liner assembly 227. The exhaust outlet 231 can be configured to allow gas flow from the processing region 220B to the circumferential pumping cavity 225 to facilitate processing within the system 200.

[0031]

[0033] 3 illustrates operations of an exemplary method 300 of semiconductor processing in accordance with some embodiments of the present technique. The method may be performed in a variety of processing chambers, including the processing system 200 described above, and any other chamber in which plasma deposition may be performed. Method 300 may include many optional operations that may or may not be particularly relevant to some embodiments of the method in accordance with the present technique.

[0032]

[0034] Method 300 may include a plasma enhanced chemical vapor deposition (PECVD) processing operation to form the as-deposited low-κ film. In embodiments, the method may include optional operations before the start of method 300, or the method may include additional operations after the deposition of the low-κ material and UV treatment. In additional embodiments, method 300 may include flowing a deposition precursor in a substrate processing region of a semiconductor processing chamber, as shown in FIG. 3 , in operation 305. In embodiments, a substrate may be present in the substrate processing region of the semiconductor processing chamber as the deposition precursor flows into the chamber.

[0033]

[0035] In some embodiments, the deposition precursor may include a silicon- and carbon-containing precursor having at least one vinyl group (i.e., a -CH=CH group). In additional embodiments, the silicon-containing precursor may include at least two vinyl groups. In yet additional embodiments, the silicon-containing precursor may be represented by Formula 1: JPEG0007815229000002.jpg31170, wherein R1, R2, and R3 may comprise a C1-C6 alkyl group or a C1-C6 alkoxy group, and at least one of R1, R2, and R3 is an alkoxy group. In a further embodiment, the silicon-containing precursor may be a vinyl-group-containing vinylmethyldimethoxysilane, which has the structural formula: JPEG0007815229000003.jpg38170 Vinylmethyldimethoxysilane It can be expressed as:

[0034]

[0036] In further embodiments, the silicon- and carbon-containing precursor can be a silicon-, carbon-, and oxygen-containing precursor. In embodiments, the silicon-, carbon-, and oxygen-containing precursor can include Si—O and Si—C bonds, and can include linear and branched silicon-containing precursors, cyclic silicon-containing precursors, or any number of additional silicon-containing precursors. In some embodiments, the silicon-containing precursor can be characterized by a specific molar ratio of carbon and / or oxygen to silicon. For example, in some embodiments, the ratio of either carbon or oxygen to silicon can be about 1 or greater, about 1.5 or greater, about 2 or greater, about 2.5 or greater, about 3 or greater, about 3.5 or greater, about 4 or greater, or even greater. Increasing the amount of carbon or oxygen relative to silicon can increase the incorporation of additional residual sites or molecules into the film. This can improve material properties and lower the dielectric constant, as discussed below.

[0035]

[0037] In still further embodiments, the silicon- and carbon-containing precursor can include a silicon-, oxygen-, and carbon-containing precursor. In embodiments, the silicon-, oxygen-, and carbon-containing precursor can be characterized by a carbon-to-oxygen ratio of about 4:1 or less, about 3:1 or less, about 2:1 or less, about 4:3 or less, or less. In embodiments, increasing the amount of oxygen in the as-deposited low-κ film provided by the silicon-, oxygen-, and carbon-containing precursor can increase the mechanical stability of the film. In additional embodiments, the amount of oxygen provided by the silicon-, oxygen-, and carbon-containing precursor can be balanced relative to the amount of carbon in the low-κ film to maintain a low value of the film's dielectric constant (κ value).

[0036]

[0038] In additional embodiments, the silicon- and carbon-containing precursors can include silicon-, oxygen-, and carbon-containing precursors having a central silicon atom and at least one methoxy group and at least one methyl group bonded to the central silicon. In embodiments, these methyl-methoxy-siloxane precursors can include DMDMOS, TMMOS, and MTMOS. In further embodiments, the silicon-containing precursor can include at least one silicon atom, at least one silicon-to-alkyl group bond, and at least one silicon-to-alkoxy group bond. In additional embodiments, the silicon-containing precursor can include a single silicon atom and an alkyl group and an alkoxy group bonded to the silicon atom. In yet further embodiments, the silicon-containing precursor can include two or more silicon atoms. In still further embodiments, the silicon-containing precursor can have alkyl groups such as ethyl, propyl, butyl, pentyl, and / or hexyl groups in addition to or in place of one or more methyl groups. In still further embodiments, the silicon-containing precursor may have alkoxy groups, such as ethoxy, propoxy, butoxy, pentoxy, and / or hexoxy groups, in addition to or in place of one or more methoxy groups. In embodiments, the silicon-containing precursor may include one or more of dimethyldimethoxysilane, bis(methyldimethoxysilyl)methane, methyltrimethoxysilane, isobutylmethyldimethoxysilane, tetramethyl-1,3-dimethoxydisiloxane, trimethylmethoxysilane, diethoxymethylsilane, octamethoxycyclotetrasiloxane, isobutyltrimethoxysilane, 1,3-dimethyl-1,1,3,3-tetramethoxydisiloxane, 1,2-bis(methyldimethoxysilyl)ethane, propylmethyldimethoxysilane, and 1,3,5,7-tetramethyl-1,3,5,7-tetramethoxycyclotetrasiloxane.

[0037]

[0039] Additional embodiments of silicon and carbon containing precursors can include those having Formula 2: JPEG0007815229000004.jpg30170Here, in Equation 2, R 1may comprise a C1-C6 alkyl group, for example, -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3, -CH2CH2CH2CH2CH3, or -CH2CH2CH2CH2CH2CH2CH3; R 2 may comprise a C1-C6 alkyl group, for example, -CH3, -CH2CH3, -CH2CH2CH3, -CH2CH2CH2CH3, -CH2CH2CH2CH2CH3, or -CH2CH2CH2CH2CH2CH2CH3; R 3 are -OCH3, -CH3, -H, -(CH2) n CH3, -O(CH2) n CH3, -CH=CH2, -CH2-CH2-(CH2CH3)2, or -CH2-CH(CH3)2, where n=1 to 5; R 4 are -OCH3, -CH3, -H, -(CH2) n CH3, -O(CH2) n It may include CH3, -CH=CH2, -CH2-CH2-(CH2CH3)2, or -CH2-CH(CH3)2, where n=1 to 5.

[0038]

[0040] In some embodiments, the deposition precursors may further include molecular oxygen (O). In embodiments, the flow rate of O relative to the flow rate of the silicon-containing precursor may be maintained at a flow rate ratio that supports the formation of low-κ films having both low-κ (κ value) and high mechanical stability, as reflected in film properties such as Young's modulus and hardness, among other things. In embodiments, the flow rate ratio of O to the silicon-containing precursor may be about 2:1 or greater, about 2.5:1 or greater, about 3:1 or greater, about 3.5:1 or greater, about 4:1 or greater, about 4.5:1 or greater, about 5:1 or greater, or greater.

[0039]

[0041] In further embodiments, the deposition precursors may also include one or more carrier gases, such as helium, argon, and nitrogen (N2). Although one or more carrier gases may be delivered along with the other deposition precursors, the carrier gas may be considered an inert gas that does not react to form part of the material as deposited.

[0040]

[0042] In additional embodiments, the flow rate of the silicon- and carbon-containing precursors can be about 2000 milligrams per minute (mgm) or greater, about 2100 mgm or greater, about 2250 mgm or greater, about 2500 mgm or greater, about 2750 mgm or greater, about 2900 mgm or greater, about 3000 mgm or greater, or greater. In further embodiments, the flow rate of O can be about 120 sccm or greater, about 130 sccm or greater, about 140 sccm or greater, about 150 sccm or greater, about 200 sccm or greater, about 250 sccm or greater, about 300 sccm or greater, about 350 sccm or greater, about 400 sccm or greater, about 450 sccm or greater, about 500 sccm or greater, or greater. In still further embodiments, the flow rate of one or more carrier gases can be about 1000 sccm or greater, about 2000 sccm or greater, about 3000 sccm or greater, about 3000 sccm or greater, about 4000 sccm or greater, about 5000 sccm or greater, or more. In further embodiments, the flow rate of the combined deposition precursors can be about 1150 sccm or greater, about 1500 sccm or greater, about 2000 sccm or greater, about 3000 sccm or greater, about 4000 sccm or greater, about 5000 sccm or greater, or more.

[0041]

[0043] In some embodiments, it has been observed that an excessive O flow rate relative to silicon- and carbon-containing precursors can increase the dielectric constant of the as-deposited material. It is believed that excessive O flow rates in such cases can increase the number of times Si-H reacts with oxygen in the film to form hydroxyl groups (-OH). In many embodiments, the dielectric constant of as-deposited silicon-, oxygen-, and carbon-containing materials is highly sensitive to the amount of hydroxyl groups in the film. A relatively small increase in the amount of hydroxyl groups in the material (an increase of about 1% or less, as represented by the FTIR peak area ratio of the material's components) can cause a relatively large increase in the dielectric constant of the film (an increase of about 10% or more). In some embodiments, the O flow rate can be about 600 sccm or less, about 400 sccm or less, about 200 sccm or less, about 150 sccm or less, or less.

[0042]

[0044] In additional embodiments, deposition precursors flowing into a substrate processing region of a semiconductor processing chamber can change the pressure within the chamber. In embodiments, the semiconductor substrate chamber pressure can be characterized as a pressure of about 1 Torr or greater, about 2 Torr or greater, about 3 Torr or greater, about 4 Torr or greater, about 5 Torr or greater, about 6 Torr or greater, about 7 Torr or greater, about 8 Torr or greater, about 9 Torr or greater, about 10 Torr, or greater during the formation of the material during deposition.

[0043]

[0045] Embodiments of method 300 may further include generating a deposition plasma from the deposition precursor in operation 310. In embodiments, the deposition plasma may be generated from the deposition precursor in a processing region of the semiconductor processing chamber, such as by providing RF power to a faceplate to generate a plasma in the substrate processing region. The deposition plasma may be generated at any of the frequencies described above and may be generated at frequencies less than 15 MHz (e.g., 13.56 MHz). Higher frequencies may be used, but in some embodiments, lower frequency plasma generation may facilitate carbon removal during processing, as opposed to higher plasma frequency operation.

[0044]

[0046] Embodiments of method 300 may further include depositing a silicon- and carbon-containing material on a substrate in operation 315. In embodiments, the substrate is present in a substrate processing region of a semiconductor processing chamber, and the silicon- and carbon-containing material is formed from deposition plasma effluents generated by a deposition plasma also present in the processing region. In some embodiments, the substrate may be characterized by a temperature of about 400° C. or less, about 390° C. or less, about 380° C. or less, about 370° C. or less, about 360° C. or less, about 350° C. or less, about 340° C. or less, about 330° C. or less, about 320° C. or less, about 310° C. or less, about 300° C. or less, or less during deposition.

[0045]

[0047] In some embodiments, the deposition rate of the as-deposited material may be greater than 500 Å / min, and may be deposited at rates of about 700 Å / min or greater, about 1,000 Å / min or greater, about 1,200 Å / min or greater, about 1,400 Å / min or greater, about 1,600 Å / min or greater, about 1,800 Å / min or greater, or about 2,000 Å / min or greater. In further embodiments, the as-deposited material may be deposited to a thickness of about 10 Å or greater, about 50 Å or greater, about 100 Å or greater, about 250 Å or greater, about 500 Å or greater, about 1,000 Å or greater, or greater. In further embodiments, the as-deposited material may be deposited in two or more deposition and UV treatment cycles to build up the final UV-treated low-κ film. In further embodiments, the number of deposition and treatment cycles can be about 3 or more, about 5 or more, about 10 or more, about 15 or more, about 20 or more, about 30 or more, about 40 or more, about 50 or more, or more.

[0046]

[0048] In embodiments, the temperature of the substrate may be set to increase the amount of weakly bonded hydrocarbon groups in the material as deposited. In additional embodiments, these hydrocarbon groups may be -C x H y x may be an integer greater than or equal to about 1 and y may be an integer greater than or equal to about 2. In additional embodiments, x may be an integer greater than or equal to about 2 and y may be an integer greater than or equal to about 2. In further embodiments, the hydrocarbon group may be an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a cyclopentyl group, a hexyl group, an isohexyl group, a cyclohexyl group, and a phenyl group, among other types of hydrocarbon groups. In further embodiments, the as-deposited silicon- and carbon-containing material may include about 5% or more, about 6% or more, about 7% or more, about 8% or more, about 8 at.% or more, about 9% or more, about 10% or more, or more hydrocarbon groups.

[0047]

[0049] In some embodiments, methyl groups in the as-deposited material may be more strongly bound in the material than other hydrocarbon groups. In these embodiments, the UV treatment operation may remove fewer methyl groups than other hydrocarbon groups. Retention of methyl groups may maintain a higher atomic percentage of carbon in the treated material, resulting in a lower dielectric constant of the material. However, methyl groups are believed to have a less destabilizing effect on the mechanical properties of low-κ films than other hydrocarbon groups. Thus, selective retention of methyl groups over other hydrocarbon groups in the treated material can lower the dielectric constant without significantly reducing the mechanical stability of the low-κ film. In embodiments, the as-deposited silicon- and carbon-containing material may include incorporation of methyl groups of about 2.5% or more, about 2.75% or more, about 3% or more, about 3.25% or more, about 3.5% or more, about 3.75% or more, about 4 at.% or more, about 4.25% or more, about 4.5% or more, about 4.75% or more, about 5% or more, or more. When deposition of silicon- and carbon-containing materials is performed at high temperatures, the amount of hydrocarbon groups in the as-deposited material decreases. At higher deposition temperatures, hydrocarbon groups are more likely to outgas from the material as volatile organic compounds (VOCs) and react with neighboring silicon and oxygen groups in the material. Thus, embodiments of method 300 include depositing silicon- and carbon-containing materials at reduced deposition temperatures, which leaves more hydrocarbon groups in the as-deposited material.

[0048]

[0050] In further embodiments, the as-deposited silicon- and carbon-containing material may contain a significant atomic percentage of carbon. In embodiments, the as-deposited material may be characterized by an amount of carbon of about 20 at.% or more, about 21 at.% or more, about 22 at.% or more, about 23 at.% or more, about 24 at.% or more, about 25 at.% or more, or more. Although the amount of as-deposited carbon decreases after the UV treatment operation, the decrease in atomic percentage does not occur as much as the decrease in the atomic percentage of hydrocarbon groups. The high amount of carbon during initial deposition and after UV treatment results in a decrease in the dielectric constant of the final UV-treated low-κ film.

[0049]

[0051] Embodiments of method 300 may further include exposing the as-deposited silicon- and carbon-containing material to a UV treatment in operation 320. In some embodiments, the UV treatment may be performed in the semiconductor processing chamber used to deposit the low-κ material. In additional embodiments, the substrate with the as-deposited low-κ material may be transferred to another semiconductor processing chamber where a UV treatment operation is performed.

[0050]

[0052] In embodiments, the UV treatment operation 320 can produce an exposed low-κ material characterized by increased porosity and a lower dielectric constant (κ value) than the as-deposited material. In further embodiments, the exposed low-κ material can be a silicon- and carbon-containing material characterized by a porosity of about 15 vol.% or greater, about 16 vol.% or greater, about 17 vol.% or greater, about 18 vol.% or greater, about 19 vol.% or greater, about 20 vol.% or greater, or even greater. The increased porosity of the exposed low-κ material can reduce the dielectric constant of the material to about 3.0 or less, about 2.9 or less, about 2.8 or less, about 2.7 or less, about 2.6 or less, or even less.

[0051]

[0053] In further embodiments, the increased porosity of the exposed low-κ material can be due to a reduction in weakly bonded hydrocarbon groups in the material. In embodiments, the exposed low-κ material can have an amount of hydrocarbon groups of about 3% or less, about 2.75% or less, about 2.5% or less, about 2.25% or less, about 2% or less, or less. In further embodiments, the reduction in the amount of hydrocarbon groups between the as-deposited low-κ material and the UV-treated low-κ material can be about 25% or more, about 30% or more, about 40% or more, about 50% or more, about 60% or more, about 70% or more, about 80% or more, about 90% or more, about 100% or more, or more.

[0052]

[0054] As discussed above, the UV treatment operation can selectively remove hydrocarbon groups other than methyl groups from the exposed low-κ material. In embodiments, the exposed low-κ material can include methyl group incorporation of about 3.5 at.% or less, about 3.25 at.% or less, about 3 at.% or less, about 2.75 at.% or less, about 2.5 at.% or less, about 2.25 at.% or less, about 2 at.% or less, about 1.75 at.% or less, about 1.5 at.% or less, about 1.25 at.% or less, about 1 at.% or less, or less. In further embodiments, the reduction in the amount of methyl group incorporation between the as-deposited low-κ material and the UV-treated low-κ material can be about 50% or less, about 45% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 10% or less, or less.

[0053]

[0055] In further embodiments, the UV treatment operation may selectively remove hydrocarbon groups from the exposed low-κ material in a relative amount greater than the overall amount of carbon removed from the material. In embodiments, the exposed low-κ material may be characterized by a carbon content of less than 20 at.%, about 19 at.% or less, about 18 at.% or less, about 17 at.% or less, about 16 at.% or less, about 15 at.% or less, or less. In further embodiments, the reduction in carbon content between the as-deposited low-κ material and the UV-treated low-κ material may be about 50% or less, about 45% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 10% or less, or less. In embodiments, the selective removal of hydrocarbon groups across all carbon-containing components in the low-κ material may produce a UV-treated low-κ material with a higher atomic percentage of carbon and a lower dielectric constant than a material starting with a lower percentage of hydrocarbon groups.

[0054]

[0056] The processing methods of the present technology include embodiments that produce UV-treated low-κ membranes characterized by high volume percent porosity and high mechanical stability. In embodiments, the UV-treated low-κ membranes can be characterized by a Young's modulus of about 5 GPa or greater, and can be characterized by a Young's modulus of about 7.5 GPa or greater, about 10 GPa or greater, about 15 GPa or greater, about 16 GPa or greater, about 17 GPa or greater, about 18 GPa or greater, about 19 GPa or greater, about 20 GPa or greater, or even higher. In further embodiments, the UV-treated low-κ membranes can be characterized by a hardness of about 2 GPa or greater, about 3 GPa or greater, about 4 GPa or greater, about 4.5 GPa or greater, about 5 GPa or greater, about 5.5 GPa or greater, about 6 GPa or greater, about 6.5 GPa or greater, about 7 GPa or greater, about 7.5 GPa or greater, about 8 GPa or greater, about 10 GPa or greater, or even higher.

[0055]

[0057] The ability of embodiments of the present technology to form UV-treated low-κ films with high porosity and high mechanical stability can be attributed in part to the amount of Si—C crosslinks within the film. In embodiments, the percentage of carbon atoms bonded with at least two silicon atoms to form Si—C—Si crosslinks can be greater than 0.03%, about 0.06% or greater, about 0.09% or greater, about 0.12% or greater, about 0.15% or greater, about 0.18% or greater, about 0.21% or greater, about 0.24% or greater, or even greater. These and other embodiments of the present technology enable the formation of UV-treated low-κ films from silicon- and carbon-containing plasma effluents with higher porosity, lower dielectric constants, higher Young's moduli, and high hardness that can be produced by conventional plasma deposition and UV-treatment methods.

[0056]

[0058] Although the foregoing description, for purposes of explanation, sets forth numerous details in order to provide a thorough understanding of various embodiments of the present technology, it will be apparent to one skilled in the art that particular embodiments may be practiced without some of these details or with additional implementation details.

[0057]

[0059] Although several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative structures, and equivalents may be used without departing from the essence of the embodiments. In addition, in order to avoid unnecessarily obscuring the technology, some well-known processes and elements have not been described. Therefore, the above description should not be construed as limiting the scope of the technology.

[0058]

[0060] Where a range of values ​​is provided, each intervening value between the upper and lower limits of that range is understood to be specifically disclosed, to the smallest unit of the lower limit (unless the context clearly dictates otherwise). Narrower ranges between any stated or unstated intervening values ​​in a stated range, as well as all other stated or intervening values ​​in such stated range, are encompassed. The upper and lower limits of any narrower range may individually be included in or excluded from the range. Each range where either, neither, or both limits are included in the narrower range is also encompassed within the technology, provided that there is a specifically excluded limit in the stated range. When a stated range includes one or both limits, ranges excluding either or both of those included limits are also included.

[0059]

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

[0060]

[0062] Additionally, the words "comprise(s) / comprising", "contain(s) / containing", and "include(s) / including", when used in this specification and the following claims, are intended to specify the presence of stated features, integers, components, or operations, but do not exclude the presence or addition of one or more other features, integers, components, operations, acts, or groups.

Claims

1. 1. A semiconductor processing method comprising: flowing a deposition precursor into a substrate processing region of a semiconductor processing chamber, the deposition precursor comprising a silicon and carbon containing precursor; generating a deposition plasma from the deposition precursor in the substrate processing region; depositing a silicon and carbon containing material on a substrate from plasma effluents of the deposition plasma, wherein the silicon and carbon containing material as deposited is characterized by 5% or more hydrocarbon groups and the silicon and carbon containing material as deposited is characterized by incorporation of 4% or more methyl groups; exposing the deposited silicon and carbon containing material to ultraviolet light, wherein the exposed silicon and carbon containing material is characterized by 2% or less hydrocarbon groups; A semiconductor processing method comprising:

2. The hydrocarbon group is —C ｘ H ｙ 2. The semiconductor processing method of claim 1, comprising: wherein x is an integer greater than or equal to 1 and y is an integer greater than or equal to 2.

3. The silicon and carbon containing precursor has the formula 1: [In the formula, R １ , R ２ , and R ３ is C １ -C ６ Alkyl group, or C １ -C ６ may contain an alkoxy group, R １ , R ２ , and R ３ at least one of which is an alkoxy group.

10. The semiconductor processing method of claim 1 .

4. 10. The semiconductor processing method of claim 1, wherein the as-deposited silicon and carbon-containing material is characterized by a carbon content of 20 at. % or more and the exposed silicon and carbon-containing material is characterized by a carbon content of 15 at. % or less.

5. 10. The semiconductor processing method of claim 1, wherein the exposed silicon and carbon containing material is characterized by an incorporation of 3.5% or less methyl groups.

6. 10. The semiconductor processing method of claim 1, wherein the exposed silicon and carbon containing material is characterized by a porosity of 15 vol. % or greater.

7. 10. The semiconductor processing method of claim 1, wherein the exposed silicon and carbon containing material is characterized by a dielectric constant of 2.6 or less.

8. 10. The semiconductor processing method of claim 1, wherein the exposed silicon and carbon containing material is characterized by a Young's modulus of 10 GPa or greater and a hardness of 2 GPa or greater.

9. 1. A semiconductor processing method comprising: flowing a deposition precursor into a substrate processing region of a semiconductor processing chamber, the deposition precursor comprising a silicon, carbon, and oxygen containing precursor; generating a deposition plasma from the deposition precursor in the substrate processing region; depositing a silicon, carbon, and oxygen containing material on a substrate from plasma effluents of the deposition plasma, wherein the substrate is characterized by a temperature of 300° C. or less during deposition of the silicon, carbon, and oxygen containing material, and wherein the silicon, carbon, and oxygen containing material as deposited is characterized by incorporation of 4% or more methyl groups; exposing the as-deposited silicon, carbon, and oxygen containing material to ultraviolet light, wherein the exposed silicon, carbon, and oxygen containing material is characterized by a dielectric constant of 2.6 or less; A semiconductor processing method comprising:

10. 10. The semiconductor processing method of claim 9, wherein the silicon, carbon, and oxygen containing material as deposited is characterized by 5% or more hydrocarbon groups and the exposed silicon, carbon, and oxygen containing material is characterized by 2% or less hydrocarbon groups.

11. The semiconductor processing method of claim 9, wherein the exposed silicon, carbon, and oxygen-containing material is characterized by an incorporation of 3.5% or less methyl groups.

12. 10. The semiconductor processing method of claim 9, wherein the silicon, carbon, and oxygen containing precursor comprises at least one vinyl group.

13. 10. The semiconductor processing method of claim 9, wherein the silicon, carbon, and oxygen containing material as deposited is characterized by a porosity of 10 vol.% or less.

14. 10. The semiconductor processing method of claim 9, wherein the exposed silicon, carbon, and oxygen containing material is characterized by a Young's modulus of 10 GPa or greater and a hardness of 2 GPa or greater.

15. 1. A semiconductor processing method comprising: flowing a deposition precursor into a substrate processing region of a semiconductor processing chamber, the deposition precursor comprising a silicon, carbon, and oxygen containing precursor having at least one vinyl group; depositing a silicon, carbon, and oxygen containing material on a substrate in the semiconductor processing chamber, wherein the silicon, carbon, and oxygen containing material as deposited is characterized by a porosity of 10 vol.% or less; exposing the as-deposited silicon, carbon, and oxygen containing material to ultraviolet light, wherein the exposed silicon, carbon, and oxygen containing material is characterized by a porosity of 15 vol. % or greater; A semiconductor processing method comprising:

16. 16. The semiconductor processing method of claim 15, wherein the silicon, carbon, and oxygen containing material as deposited is deposited from deposition plasma effluents formed from a deposition plasma generated by the deposition precursor.

17. 16. The semiconductor processing method of claim 15, wherein the exposed silicon, carbon, and oxygen containing material is characterized by 0.1% or more Si-C-Si bonds.

18. 16. The semiconductor processing method of claim 15, wherein the exposed silicon, carbon, and oxygen containing material is characterized by a Young's modulus of 10 GPa or greater and a hardness of 2 GPa or greater.

19. 16. The semiconductor processing method of claim 15, wherein the exposed silicon, carbon, and oxygen containing material is characterized by an incorporation of 3.5% or less methyl groups.

20. 16. The semiconductor processing method of claim 15, wherein the exposed silicon, carbon, and oxygen containing material is characterized by a dielectric constant of 2.6 or less.

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