Semiconductor device and preparation method thereof
By forming a carbon-based reducing sol protective layer on the surface of the low-dielectric constant material layer to block high-energy photons and oxidative plasma, the problem of increasing the dielectric constant of the material is solved and the performance of semiconductor devices is improved.
Patent Information
- Application Number
- CN202510144989.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2025-05-06
AI Technical Summary
When the prior art, when the dielectric constant of the material is reduced, the surface of the low-diplier constant dielectric material is easily damaged by high-energy photon radiation and an oxidative plasma environment, resulting in an increase in the dielectric constant and affecting the performance of semiconductor devices.
The sol protective layer formed by carbon-based reducing sol covers the surface of the low-dielectric constant material layer, blocks the contact between high-energy photons and oxidizing plasma, and forms a reducing plasma on the surface, consumes oxidizing substances and repairs damage to the material surface.
It effectively prevents the increase in the dielectric constant of the low-dielectric constant material layer, maintains the carbon content and porosity of the material, and improves the electrical performance of semiconductor devices.
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Figure CN119943814A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a semiconductor device and a preparation method thereof. Background Art
[0002] In recent years, as integrated circuits continue to develop in the direction of miniaturization, the resistance and capacitance of the metal wiring inside the device and the capacitance of the insulating dielectric layer have caused delays, crosstalk, and power consumption, which have become the main factors limiting device performance. For this reason, low-resistivity metal wires and low-dielectric constant dielectric materials are usually used between the layers and wires of the wiring to reduce parasitic capacitance, thereby achieving the purpose of improving device performance.
[0003] There are currently two main methods to reduce the dielectric constant of materials: one is to reduce the polarity of the material itself, including reducing the electronic polarizability, ionic polarizability and molecular polarizability in the material, such as introducing carbon (C) elements into silicon dioxide, and using the low polarity network formed by Si-C and CC bonds to reduce the dielectric constant of the material; the second is to increase the void density in the material, thereby reducing the molecular density of the material, such as introducing methyl (-CH3) in the process of growing silicon dioxide to form a loose porous film.
[0004] However, when a mask is formed on the surface of a low-dielectric constant dielectric material, on the one hand, high-energy photon radiation will damage the low-dielectric constant dielectric material, and on the other hand, the oxidizing plasma environment will cause the methyl group (-CH3) to be oxidized and detached by the polar ions in the plasma, thereby increasing the dielectric constant of the low-dielectric constant dielectric material. Summary of the invention
[0005] Based on this, it is necessary to provide a semiconductor device and a method for preparing the same in response to the problems in the above-mentioned background technology, which can at least avoid the increase of the dielectric constant of the low dielectric constant material layer and improve the performance of the semiconductor device.
[0006] To achieve the above-mentioned purpose and other related purposes, one aspect of the present application provides a semiconductor device, comprising: a substrate; a low dielectric constant material layer, located on one side of the substrate, the low dielectric constant material layer comprising a carbon-doped porous material; a sol protective layer, arranged on a surface of the low dielectric constant material layer facing away from the substrate, the sol protective layer is formed by a carbon-based reducing sol, and the carbon-based reducing sol forms a reducing plasma on the surface of the low dielectric constant material layer.
[0007] In one embodiment, the carbon-based reducing sol includes: a carbon-based reducing solvent, the carbon-based reducing solvent includes a small molecule alcohol, and the molecular weight of the small molecule alcohol is less than 100 g / mol.
[0008] In one embodiment, the carbon-doped porous material includes a plurality of methyl groups, and the carbon-based reducing solvent includes a monohydric alcohol.
[0009] In one embodiment, the size of the small molecule alcohol is smaller than the size of the pores in the carbon-doped porous material, and the small molecule alcohol infiltrates into the carbon-doped porous material. The size of the pores in the carbon-doped porous material ranges from 0.5 nm to 2 nm.
[0010] In one embodiment, the carbon-based reducing sol further includes: a film-forming solvent, the film-forming solvent includes a polyol, and the molecular weight of the film-forming solvent is less than 300 g / mol; a stabilizer, the stabilizer includes dimethylamide; a binder, the molecular weight of the binder is less than 10000 g / mol, and the binder includes polyvinyl alcohol.
[0011] In one embodiment, the weight percentage of the carbon-based reducing solvent is 5wt%~70wt%, the weight percentage of the membrane-forming solvent is 5wt%~50wt%, the weight percentage of the stabilizer is 5wt%~50wt%, and the weight percentage of the binder is 2wt%~20wt%.
[0012] In one embodiment, the low dielectric constant material layer includes carbon-doped silicon hydroxide, and the dielectric constant of the low dielectric constant material layer ranges from 2.7 to 3.3.
[0013] In one embodiment, the semiconductor device further includes: a hard mask layer, which is disposed on a surface of the sol protective layer facing away from the substrate, and the material of the hard mask layer includes silicon dioxide.
[0014] Another aspect of the present invention provides a method for preparing a semiconductor device, comprising the following steps:
[0015] providing a substrate;
[0016] forming a low dielectric constant material layer on a substrate, wherein the low dielectric constant material layer comprises a carbon-doped porous material;
[0017] The carbon-based reducing sol is coated on the surface of the low dielectric constant material layer away from the substrate to form a sol protection layer, and the carbon-based reducing sol forms reducing plasma on the surface of the low dielectric constant material layer.
[0018] In one embodiment, the method for preparing a semiconductor device further includes: forming a hard mask layer on a surface of the sol protective layer facing away from the substrate based on oxidizing ions.
[0019] According to the semiconductor device and preparation method thereof provided by the present invention, a sol protective layer formed by a carbon-based reducing sol is arranged on the surface of the low dielectric constant material layer. The sol protective layer can serve as a barrier layer to prevent external ions from contacting the surface of the low dielectric constant material layer and prevent the escape of ions on the surface of the low dielectric constant material layer. At the same time, the sol protective layer can form a reducing plasma on the surface of the low dielectric constant material layer, consume external oxidizing ions and repair damage to the surface of the low dielectric constant material layer, avoid a decrease in the carbon content and porosity of the carbon-doped porous material of the low dielectric constant material layer, avoid an increase in the dielectric constant value of the low dielectric constant material layer, and improve the performance of the semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to better describe and illustrate the embodiments and / or examples of those applications disclosed herein, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the embodiments and / or examples currently described, and the best modes of these applications currently understood.
[0021] Figure 1A A schematic diagram showing the reaction on the surface of the low dielectric constant material layer;
[0022] Figure 1B A schematic diagram of a structure after a hard mask is formed on a low dielectric constant material layer is shown;
[0023] Figure 2 is a flow chart of a method for preparing a semiconductor device provided in an embodiment;
[0024] Figure 3A It is a schematic cross-sectional structural diagram of the structure after the low dielectric constant material layer is formed in step S202 of the method for preparing a semiconductor device provided in an embodiment;
[0025] Figure 3B It is a schematic cross-sectional structural diagram of the structure after the sol protective layer is formed in step S203 of the method for preparing a semiconductor device provided in an embodiment;
[0026] Figure 3C It is a schematic cross-sectional structural diagram of the structure after a hard mask layer is formed in a method for preparing a semiconductor device provided in an embodiment.
[0027] Description of reference numerals:
[0028] 100, substrate; 110, low dielectric constant material layer; 111, damaged area; 120, hard mask layer; 130, sol protective layer. DETAILED DESCRIPTION
[0029] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0031] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.
[0032] Spatially relative terms such as "under," "below," "below," "under," "above," "above," etc., may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatially relative terms are intended to include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "on" the other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.
[0033] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.
[0034] Embodiments of the application are described herein with reference to cross-sectional views that are schematic diagrams of ideal embodiments (and intermediate structures) of the application. Thus, variations from the shapes shown due to, for example, manufacturing techniques and / or tolerances can be expected. Therefore, embodiments of the application should not be limited to the specific shapes of the zones shown herein, but rather include shape deviations due to, for example, manufacturing, and the zones shown in the figures are schematic in nature, and their shapes are not intended to display the actual shapes of the zones of the device and are not intended to limit the scope of the application.
[0035] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner. Although the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation, the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout type may also be more complicated.
[0036] At present, SiOCH (carbon-doped silicon hydroxide) is one of the most widely used low dielectric constant (k) materials. Figure 1A and Figure 1B In the example shown, the low dielectric constant material layer 110 is a SiOCH film, which is porous due to its rich methyl groups (-CH3). A hard mask layer 120 is usually formed on the surface of the SiOCH film. Figure 1A and Figure 1B In the example shown, the hard mask layer 120 includes tetraethyl orthosilicate deposited silicon dioxide (TEOS-SiO2). When TEOS-SiO2 is formed on the surface of the SiOCH film, the generated high-energy photons (UV) cause the methyl groups (-CH3) on the surface of the SiOCH to be separated, such as Figure 1AAs shown in the figure, the loss of methyl (-CH3) in SiOCH leads to a decrease in film porosity, an increase in dielectric constant K, and a decrease in electrical properties. Furthermore, as a hydrophobic group, methyl (-CH3) is removed from the surface of SiOCH and makes it easier to absorb water, which further increases the dielectric constant K and further reduces the electrical properties. In addition, when depositing TEOS-SiO2, there is a high density of oxidizing ions (such as O x y- Oxygen ions, such as oxygen ions, react with methyl (-CH3), methylene (-CH2) and other groups in SiOCH, such as Figure 1A As shown in FIG. 1 , the carbon content in SiOCH is reduced, the SiOCH film is densified, the dielectric constant K is increased, and the electrical properties are deteriorated. Therefore, the process of depositing TEOS-SiO2 forms a damaged area 111 on the surface of the low dielectric constant material layer 110. Finally, the stacked structure formed by the low dielectric constant material layer 110 and the hard mask layer 120 is as shown in FIG. Figure 1B shown.
[0037] In view of the above problems, the present invention provides a method for preparing a semiconductor device, such as Figure 2 As shown, the following steps are included:
[0038] Step S201: providing a substrate;
[0039] Step S202: forming a low dielectric constant material layer on the substrate, wherein the low dielectric constant material layer includes a carbon-doped porous material;
[0040] Step S203: coating the carbon-based reducing sol on the surface of the low dielectric constant material layer facing away from the substrate to form a sol protection layer, and the carbon-based reducing sol forms reducing plasma on the surface of the low dielectric constant material layer.
[0041] First, execute step S201, refer to Figure 3A As shown, a substrate 100 is provided.
[0042] In one embodiment, the substrate 100 may be at least one of the following materials: silicon, silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI), germanium on insulator (GeOI), etc.
[0043] Then execute step S202, refer to Figure 3A As shown, a low dielectric constant material layer 110 is formed on a substrate 100 , and the low dielectric constant material layer 110 includes a carbon-doped porous material.
[0044] In one embodiment, the low dielectric constant material layer 110 includes a carbon-doped porous material, and the carbon-doped porous material includes but is not limited to SiOCH (carbon-doped silicon hydroxide). The dielectric constant range of the low dielectric constant material layer includes 2.7~3.3, such as 2.7, 3.0, 3.3, etc. The precursor used to form SiOCH usually contains silicon (Si) elements, carbon (C) elements, oxygen (O) elements and hydrogen (H) elements. In this embodiment, the precursor used to form SiOCH usually contains methyl (-CH3). For example, the precursor used to form SiOCH includes but is not limited to hexamethyldisiloxane, octamethylcyclotetrasiloxane (OMCTS), etc. The reaction gas used to form SiOCH includes oxygen (O2). Specifically, the precursor and the reaction gas are formed by chemical vapor deposition (CVD) and the like under the action of a high-frequency radio frequency power supply. Chemical vapor deposition (CVD) includes but is not limited to one of low-pressure chemical vapor deposition (LPCVD), plasma enhanced chemical vapor deposition (PECVD), ultra-high vacuum chemical vapor deposition (UHVCVD), rapid thermal chemical vapor deposition (RTCVD) and molecular beam epitaxy (MBE).
[0045] In one embodiment, the low dielectric constant material layer 110 includes a carbon-doped porous material, and the carbon-doped porous material includes but is not limited to SiOCH (carbon-doped silicon hydroxide). The method of reducing the dielectric constant of the material includes reducing the polarity of the material itself. In this embodiment, the low dielectric constant material layer 110 adopts a carbon-doped material, and the carbon (C) element is introduced into silicon dioxide, and the dielectric constant is reduced by using the low polarity network formed by the formed Si-C and CC bonds. The method of reducing the dielectric constant of the material includes increasing the void density in the material. In this embodiment, the low dielectric constant material layer 110 adopts a porous material, and a loose porous SiOCH is formed by introducing a methyl group (-CH3) during the growth of silicon dioxide. Specifically, the size range of the holes in the carbon-doped porous material includes 0.5nm~2nm, for example 0.5nm, 1nm, 2nm.
[0046] Then execute step S203, as Figure 3B As shown, the carbon-based reducing sol is coated on the surface away from the substrate 100 to form a sol protective layer 130, and the carbon-based reducing sol forms reducing plasma on the surface of the low dielectric constant material layer 110. Further, the carbon-based reducing sol includes a carbon-based reducing solvent, a film-forming solvent, a stabilizer and a binder.
[0047] In one embodiment, the carbon-based reducing solvent uses small molecule alcohols, such as methanol (CH3OH), ethanol (C2H6O) and other monohydric alcohols as solvents to improve the dispersibility of the carbon-based reducing sol. The molecular weight of the small molecule alcohol is less than 100 g / mol, such as the molecular weight (i.e., relative molecular mass) of methanol (CH3OH) is 32.04, and the molecular weight of ethanol (C2H6O) is 46.07. The size of the small molecule alcohol is smaller than the size of the pores in the carbon-doped porous material, and the small molecule alcohol penetrates into the carbon-doped porous material and attaches to the polar center. The weight percentage of the carbon-based reducing solvent in the carbon-based reducing sol is 5wt%~70wt%, for example, 5wt%, 50wt%, and 70wt%.
[0048] In one embodiment, the film-forming solvent includes a polyol, such as ethylene glycol (CH2OH)2, etc., which is used to increase the viscosity and surface tension of the solution so that the sol can be spin-coated evenly to facilitate film formation. The molecular weight of the film-forming solvent is usually greater than the molecular weight of the carbon-based reducing solvent, and the molecular weight of the film-forming solvent is less than 300g / mol, such as the molecular weight of ethylene glycol (CH2OH)2 is 46.07. The film-forming solvent is not easy to penetrate into the carbon-doped porous material, but forms a sol protective layer 130 on the surface of the low dielectric constant material layer 110 away from the substrate 100. The weight percentage of the film-forming solvent in the carbon-based reducing sol is 5wt%~50wt%, for example, 5wt%, 30wt%, 50wt%.
[0049] In one embodiment, the stabilizer is used to increase the thermal stability of the carbon-based reducing sol and prevent excessive loss of solvent (carbon-based reducing solvent and film-forming solvent) during the drying process of the carbon-based reducing sol. The stabilizer includes but is not limited to dimethylamide compounds, such as N,N-dimethylformamide (C3H7NO, DMF). The weight percentage of the stabilizer in the carbon-based reducing sol is 5wt%~50wt%, such as 5wt%, 30wt%, 50wt%.
[0050] In one embodiment, the binder is used to increase the viscosity of the carbon-based reducing sol so that the carbon-based reducing sol can be evenly coated. The binder includes but is not limited to polyvinyl alcohol ([C2H4O] n , PVA). The molecular weight of the binder is usually greater than the molecular weight of the membrane-forming solvent, and the molecular weight of the binder is less than 10000 g / mol. The weight percentage of the binder in the carbon-based reducing sol is 2wt% to 20wt%, such as 2wt%, 10wt%, and 20wt%.
[0051] In one embodiment, the carbon-based reducing sol can be coated on the surface of the low dielectric constant material layer 110 by spin coating. Specifically, the carbon-based reducing sol can be dripped on the surface of the low dielectric constant material layer 110 when stationary, and then accelerated to a predetermined speed (i.e., static spin coating); or the glue can be dripped when the substrate is rotating (i.e., dynamic spin coating). The carbon-based reducing sol is diffused on the surface of the low dielectric constant material layer 110 by the centrifugal force to form a uniform sol protective layer 130, and the thickness of the sol protective layer 130 can be controlled by the rotation speed and / or the rotation time. In addition, the sol protective layer 130 can also be cured by processes such as light irradiation or heating.
[0052] By forming a sol protective layer 130 on the surface of the low dielectric constant material layer, the sol protective layer covers the surface of the low dielectric constant material layer as a solid coating, and can serve as a barrier layer to block high-energy photons, oxygen-based plasma and other substances from contacting the surface of the low dielectric constant material layer, and at the same time block methyl (-CH3) and other substances from escaping from the surface of the low dielectric constant material layer. Figure 3B On the other hand, the formed sol protective layer 130 includes reducing carbon bonds (e.g. -C x H y , -CC, etc.), dissociate into reducing plasma on the surface of the low dielectric constant material layer, which can react with oxidizing substances such as oxygen-based plasma to consume oxidizing substances, and can also repair the damaged surface of the low dielectric constant material layer, avoiding the decrease of carbon content and porosity of the low dielectric constant material layer, thereby avoiding the increase of the k value of the low dielectric constant material layer. Further, by adjusting the carbon content of the sol protective layer 130, when the carbon content of the sol protective layer 130 matches the amount of oxidizing substances, the oxidizing ions in the TEOS-SiO2 deposition process can be completely exhausted, thereby maintaining the k value of the low dielectric constant material layer to the greatest extent.
[0053] Next, refer to Figure 3C As shown, the method further includes forming a hard mask layer 120 on a surface of the sol protective layer 130 facing away from the substrate 100 based on oxidative ions.
[0054] In one embodiment, the material of the hard mask layer 120 includes but is not limited to tetraethyl orthosilicate-deposited silicon dioxide (TEOS-SiO2). Specifically, when tetraethyl orthosilicate (TEOS) is used as a precursor to deposit silicon dioxide (SiO2), on the one hand, oxygen (O2) is used as a reaction gas, and on the other hand, a high-density oxygen plasma (e.g., O x y-), in the process of forming the hard mask layer 120 based on oxidizing ions, the carbon-based reducing solvent in the sol protective layer 130 dissociates into reducing plasma on the surface of the low dielectric constant material layer 110, which is used to consume the oxidizing ions and repair the damaged SiOCH, thereby avoiding damage to the low dielectric constant material layer 110, avoiding a reduction in the carbon content of the carbon-doped porous material, and avoiding a reduction in the size and number of pores in the carbon-doped porous material, thereby avoiding an increase in the dielectric constant K and improving electrical properties.
[0055] By forming a sol protective layer 130 on the surface of the low dielectric constant material layer 110, during TEOS-SiO2 deposition, the sol protective layer 130 can play the following roles: (1) acting as a barrier layer to block the irradiation of high-energy photons in the plasma, thereby preventing the methyl groups (-CH3) in the low dielectric constant material layer 110 from escaping; (2) acting as a barrier layer to block the heavy oxidizing ions in the plasma from diffusing into the carbon-doped porous material, thereby preventing the methyl groups (-CH3) in the doped porous material from being oxidized; (3) acting as a supporting structure to prevent the pores in the carbon-doped porous material from collapsing at high temperatures during TEOS-SiO2 deposition; (4) acting as a sacrificial layer and a repair layer, during TEOS-SiO2 deposition, the small molecule reducing alcohol solvent in the carbon-based reducing sol diffuses to the SiOCH surface and dissociates into reducing plasma, which is used to consume the O-based ions (-O x H y ) and repair SiOCH damaged by plasma.
[0056] So far, the introduction of the relevant steps of the method for preparing a semiconductor device according to an embodiment of the present invention has been completed. It can be understood that the method for preparing a semiconductor device according to this embodiment not only includes the above steps, but also may include other necessary steps before, during or after the above steps, which are all included in the scope of the manufacturing method according to this embodiment.
[0057] The present invention provides a semiconductor device, referring to Figure 3C As shown, including:
[0058] Substrate 100;
[0059] A low dielectric constant material layer 110 is located on one side of the substrate 100, and the low dielectric constant material layer 110 includes a carbon-doped porous material;
[0060] The sol protective layer 130 is disposed on the surface of the low dielectric constant material layer 110 facing away from the substrate 100 . The sol protective layer 130 is formed of a carbon-based reducing sol, and the carbon-based reducing sol forms a reducing plasma on the surface of the low dielectric constant material layer 110 .
[0061] In one embodiment, the substrate 100 may be at least one of the following materials: silicon, silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI), germanium on insulator (GeOI), etc.
[0062] In one embodiment, the low dielectric constant material layer 110 includes a carbon-doped porous material, and the carbon-doped porous material includes but is not limited to SiOCH (carbon-doped silicon hydroxide). The dielectric constant range of the low dielectric constant material layer includes 2.7~3.3, such as 2.7, 3.0, 3.3, etc. The method of reducing the dielectric constant of the material includes reducing the polarity of the material itself. In this embodiment, the low dielectric constant material layer 110 adopts a carbon-doped material, and the carbon (C) element is introduced into silicon dioxide, and the dielectric constant is reduced by the low polarity network formed by the formed Si-C and CC bonds. The method of reducing the dielectric constant of the material includes increasing the void density in the material. In this embodiment, the low dielectric constant material layer 110 adopts a porous material, and a methyl group (-CH3) is introduced during the growth of silicon dioxide to form a loose and porous SiOCH. Specifically, the size range of the pores in the carbon-doped porous material includes 0.5nm~2nm, such as 0.5nm, 1nm, 2nm.
[0063] In one embodiment, the sol protective layer 130 is formed by a carbon-based reducing sol, and the carbon-based reducing sol includes a carbon-based reducing solvent, a film-forming solvent, a stabilizer and a binder. The carbon-based reducing solvent uses a small molecule alcohol, such as a monohydric alcohol such as methanol (CH3OH) and ethanol (C2H6O) as a solvent to improve the dispersibility of the carbon-based reducing sol. The molecular weight of the small molecule alcohol is less than 100g / mol, such as the molecular weight (i.e., relative molecular mass) of methanol (CH3OH) is 32.04, and the molecular weight of ethanol (C2H6O) is 46.07. The size of the small molecule alcohol is smaller than the size of the pores in the carbon-doped porous material, and the small molecule alcohol penetrates into the carbon-doped porous material and adheres to the polar center. The weight percentage of the carbon-based reducing solvent in the carbon-based reducing sol is 5wt%~70wt%, for example, 5wt%, 50wt%, and 70wt%. The film-forming solvent includes a polyol, such as ethylene glycol (CH2OH)2, etc., which is used to increase the viscosity and surface tension of the solution so that the sol can be evenly spin-coated to facilitate film formation. The molecular weight of the film-forming solvent is usually greater than that of the carbon-based reducing solvent, and the molecular weight of the film-forming solvent is less than 300g / mol, such as the molecular weight of ethylene glycol (CH2OH)2 is 46.07. The film-forming solvent is not easy to penetrate into the carbon-doped porous material, but forms a sol protective layer 130 on the surface of the low dielectric constant material layer 110 away from the substrate 100. The weight percentage of the film-forming solvent in the carbon-based reducing sol is 5wt%~50wt%, such as 5wt%, 30wt%, 50wt%. The stabilizer is used to increase the thermal stability of the carbon-based reducing sol and prevent the excessive loss of solvents (carbon-based reducing solvents and film-forming solvents) during the drying process of the carbon-based reducing sol. Stabilizers include but are not limited to dimethylamide compounds, such as N,N-dimethylformamide (C3H7NO, DMF). The weight percentage of the stabilizer in the carbon-based reducing sol is 5wt% to 50wt%, such as 5wt%, 30wt%, and 50wt%. The binder is used to increase the viscosity of the carbon-based reducing sol so that the carbon-based reducing sol can be evenly coated. The binder includes but is not limited to polyvinyl alcohol ([C2H4O] n , PVA). The molecular weight of the binder is usually greater than the molecular weight of the membrane-forming solvent, and the molecular weight of the binder is less than 10000 g / mol. The weight percentage of the binder in the carbon-based reducing sol is 2wt% to 20wt%, such as 2wt%, 10wt%, and 20wt%.
[0064] By forming the sol protective layer 130 on the surface of the low dielectric constant material layer, on the one hand, the sol protective layer covers the surface of the low dielectric constant material layer as a solid coating, and can serve as a barrier layer to block high-energy photons, oxygen-based plasma and other substances from contacting the surface of the low dielectric constant material layer, and at the same time block methyl (-CH3) and other substances from escaping from the surface of the low dielectric constant material layer. On the other hand, the formed sol protective layer 130 includes reducing carbon bonds (such as -C x Hy , -CC, etc.), dissociate into reducing plasma on the surface of the low dielectric constant material layer, which can react with oxidizing substances such as oxygen-based plasma to consume oxidizing substances, and can also repair the damaged surface of the low dielectric constant material layer, avoiding the decrease of carbon content and porosity of the low dielectric constant material layer, thereby avoiding the increase of the k value of the low dielectric constant material layer. Further, by adjusting the carbon content of the sol protective layer 130, when the carbon content of the sol protective layer 130 matches the amount of oxidizing substances, the oxidizing ions in the TEOS-SiO2 deposition process can be completely exhausted, thereby maintaining the k value of the low dielectric constant material layer to the greatest extent.
[0065] In one embodiment, the material of the hard mask layer 120 includes but is not limited to tetraethyl orthosilicate-deposited silicon dioxide (TEOS-SiO2). Specifically, when tetraethyl orthosilicate (TEOS) is used as a precursor to deposit silicon dioxide (SiO2), oxygen (O2) is used as a reaction gas on the one hand, and on the other hand, there is a high-density oxygen-based plasma in the reaction chamber. In the process of forming the hard mask layer 120 based on oxidizing ions, the carbon-based reducing solvent in the sol protective layer 130 dissociates into reducing plasma on the surface of the low dielectric constant material layer 110, which is used to consume oxidizing ions and repair damaged SiOCH, thereby preventing the low dielectric constant material layer 110 from being damaged, preventing the carbon content of the carbon-doped porous material from being reduced, and preventing the size and number of holes in the carbon-doped porous material from being reduced, thereby preventing the dielectric constant K from increasing and improving electrical performance.
[0066] According to the semiconductor device and preparation method thereof provided by the present invention, a sol protective layer formed by a carbon-based reducing sol is arranged on the surface of the low dielectric constant material layer. The sol protective layer can serve as a barrier layer to prevent external ions from contacting the surface of the low dielectric constant material layer and prevent the escape of ions on the surface of the low dielectric constant material layer. At the same time, the sol protective layer can form a reducing plasma on the surface of the low dielectric constant material layer, consume external oxidizing ions and repair damage to the surface of the low dielectric constant material layer, avoid a decrease in the carbon content and porosity of the carbon-doped porous material of the low dielectric constant material layer, avoid an increase in the dielectric constant value of the low dielectric constant material layer, and improve the performance of the semiconductor device.
[0067] Please note that the above embodiments are for illustrative purposes only and are not intended to limit the present application.
[0068] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.
[0069] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0070] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.
Claims
1. A semiconductor device, characterized in that: include: substrate; A low dielectric constant material layer, located on one side of the substrate, the low dielectric constant material layer comprising a carbon-doped porous material; The sol protective layer is arranged on the surface of the low dielectric constant material layer away from the substrate. The sol protective layer is formed by a carbon-based reducing sol, and the carbon-based reducing sol forms a reducing plasma on the surface of the low dielectric constant material layer.
2. The semiconductor device according to claim 1, wherein: The carbon-based reducing sol comprises: A carbon-based reducing solvent, wherein the carbon-based reducing solvent comprises a small molecule alcohol, and the molecular weight of the small molecule alcohol is less than 100 g / mol.
3. The semiconductor device according to claim 2, characterized in that The carbon-doped porous material includes a plurality of methyl groups, and the carbon-based reducing solvent includes a monohydric alcohol.
4. The semiconductor device according to claim 2, characterized in that The size of the small molecule alcohol is smaller than the size of the pores in the carbon-doped porous material. The small molecule alcohol infiltrates into the carbon-doped porous material. The size of the pores in the carbon-doped porous material ranges from 0.5 nm to 2 nm.
5. The semiconductor device according to claim 2, wherein: The carbon-based reducing sol also includes: A film-forming solvent, wherein the film-forming solvent comprises a polyol, and the molecular weight of the film-forming solvent is less than 300 g / mol; A stabilizer, the stabilizer comprising dimethyl amide; The binder has a molecular weight of less than 10000 g / mol and comprises polyvinyl alcohol.
6. The semiconductor device according to claim 5, characterized in that In the carbon-based reducing sol, the weight percentage of the carbon-based reducing solvent is 5wt%~70wt%, the weight percentage of the membrane-forming solvent is 5wt%~50wt%, the weight percentage of the stabilizer is 5wt%~50wt%, and the weight percentage of the binder is 2wt%~20wt%.
7. The semiconductor device according to claim 1, wherein: The low dielectric constant material layer includes carbon-doped silicon hydroxide, and the dielectric constant of the low dielectric constant material layer ranges from 2.7 to 3.
3.
8. The semiconductor device according to claim 1, wherein: Also includes: A hard mask layer is arranged on a surface of the sol protective layer away from the substrate, and a material of the hard mask layer includes silicon dioxide.
9. A method for preparing a semiconductor device, characterized in that: The steps include: providing a substrate; forming a low dielectric constant material layer on the substrate, wherein the low dielectric constant material layer comprises a carbon-doped porous material; A carbon-based reducing sol is coated on a surface of the low dielectric constant material layer facing away from the substrate to form a sol protection layer, and the carbon-based reducing sol forms reducing plasma on the surface of the low dielectric constant material layer.
10. The method for preparing a semiconductor device according to claim 9, characterized in that: Also includes: A hard mask layer is formed on a surface of the sol protective layer facing away from the substrate based on oxidative ions.