Dielectric structure, method of manufacture, and semiconductor device

Abstract

The present application provides a dielectric structure, a preparation method and a semiconductor device. The method for preparing a dielectric structure comprises: forming a recess in a substrate; forming a filling layer in the recess, wherein the filling layer fills at least part of the space of the recess; and shrinking the volume of the filling layer to release at least part of the space in which the recess is filled.

Description

Technical Field

[0001] This application relates to the field of semiconductor design and manufacturing, and more specifically, to a dielectric structure, a method for preparing the dielectric structure, and a semiconductor device. Background Technology

[0002] With the continuous improvement of the performance of very large-scale integrated circuits (VLSI), higher requirements are placed on the size of components. The reduction in component size means that the metal interconnects in integrated circuits (ICs) must be thinner, and the line spacing and layer spacing must be reduced. The increased interconnect resistance R and parasitic capacitance C significantly increase the interconnect time constant RC. The transmission speed of electrical signals in ICs has gradually shifted from being controlled primarily by logic gate delay time to being mainly controlled by the interconnect time constant RC. Therefore, there is a technical need to reduce RC delay in order to improve the electrical performance of electronic circuits.

[0003] It should be understood that the content described in the background section is only for the purpose of helping to understand the technical solutions disclosed in this application, and is not necessarily prior art before the filing date of this application. Summary of the Invention

[0004] This application provides a method for fabricating a dielectric structure, comprising: forming a groove in a substrate; forming a filling layer in the groove, wherein the filling layer fills at least a portion of the space in the groove; and shrinking the volume of the filling layer to release at least a portion of the space in the groove that was filled.

[0005] In one embodiment, before shrinking the volume of the filler layer, the method further includes forming an initial dielectric layer on the filler layer and the substrate, wherein the initial dielectric layer has mesoporous structures.

[0006] In one embodiment, the filling layer comprises a swellable material that absorbs a solution and fills at least a portion of the space in the groove in a swollen state, and the method of shrinking the volume of the filling layer comprises: at least partially removing the solution.

[0007] In one embodiment, after shrinking the volume of the filler layer, the method further includes: removing the filler layer; and converting the initial dielectric layer into a dielectric layer, wherein the density of the dielectric layer is greater than the density of the initial dielectric layer.

[0008] In one embodiment, the method for removing the filler layer includes using a dry oxygen thermal oxidation process to remove the filler layer, and the method for converting the initial dielectric layer into the dielectric layer includes using a water vapor thermal oxidation process to convert the initial dielectric layer into the dielectric layer.

[0009] In one embodiment, the filler layer comprises a material with shrinkage properties.

[0010] In one embodiment, the method of forming the shrinkable material in the groove includes dissolving a first material in a first solvent and coating it into the groove using a spin coating process, and the method of shrinking the volume of the shrinkable material includes at least removing a portion of the first solvent; or the method of forming the shrinkable material in the groove includes depositing the shrinkable material into the groove using a flowable chemical vapor deposition process, and the method of shrinking the volume of the shrinkable material includes heating the shrinkable material and cooling it to solidify, wherein the shrinkable material includes the first material.

[0011] In one embodiment, after shrinking the volume of the filling layer, the method further includes: converting the initial dielectric layer into a dielectric layer, wherein the density of the initial dielectric layer is less than the density of the dielectric layer.

[0012] In one embodiment, the method of forming the fill layer includes: forming an initial fill layer in the groove and on the substrate; and removing a portion of the initial fill layer located on the substrate, and removing a portion of the initial fill layer located in the groove and connected to the initial fill layer portion on the substrate, wherein the unremoved portion of the initial fill layer forms the fill layer.

[0013] In one embodiment, the filler layer includes first filler particles, each of the first filler particles comprising a swellable material coated with a mesoporous material.

[0014] In one embodiment, the method of forming the first filling particle in the groove includes: forming the swellable material that absorbs the solution; coating the surface of the swellable material with a mesoporous material; and dissolving the swellable material coated with the mesoporous material in a second solvent and coating it into the groove.

[0015] In one embodiment, the method for shrinking the volume of the first filler particles includes at least partially removing the solution, wherein the step of shrinking the volume of the first filler particles is performed before the step of dissolving the swellable material coated with mesoporous material in the second solvent, or the step of shrinking the volume of the first filler particles is performed after the step of coating the swellable material coated with mesoporous material into the groove.

[0016] In one embodiment, the filling layer includes second filling particles, each of the second filling particles comprising a shrinkable material coated with a mesoporous material, wherein the shrinkage of the mesoporous material is less than the shrinkage of the shrinkable material.

[0017] In one embodiment, after shrinking the volume of the filling layer, the method further includes: converting the mesoporous material in the filling layer located at the top of the groove into a dielectric layer, wherein the density of the dielectric layer is greater than the density of the mesoporous material.

[0018] In one embodiment, before shrinking the volume of the filling layer, the method further includes: forming an initial dielectric layer on the filling layer and the substrate, wherein the initial dielectric layer has mesoporous structures; and after shrinking the volume of the filling layer, the method further includes: converting the initial dielectric layer and the mesoporous material in the filling layer located at the top of the groove into a dielectric layer, wherein the density of the dielectric layer is greater than the density of the mesoporous material.

[0019] This application also provides a dielectric structure comprising: a substrate having a groove; and a dielectric layer suspended at the top of the groove and in contact with the substrate to close the groove at the top, wherein the groove has a void.

[0020] In one embodiment, at least half of the surface of the dielectric layer facing the bottom of the groove is suspended.

[0021] In one embodiment, the dielectric structure further includes a filling layer located within the groove and filling at least a portion of the groove.

[0022] In one embodiment, the filling layer includes first filling particles, each of the first filling particles including a swellable material coated with a mesoporous material, wherein the voids are located between the mesoporous material and the swellable material, and between pairs of the first filling particles; or the filling layer includes second filling particles, each of the second filling particles including a shrinkable material coated with a mesoporous material, wherein the voids are located between the mesoporous material and the shrinkable material, and between pairs of the second filling particles.

[0023] In another aspect, this application provides a semiconductor device, comprising: a dielectric structure as described in any of the above embodiments; and a first structure connected to the dielectric structure. Attached Figure Description

[0024] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0025] Figure 1 This is a flowchart of a method for fabricating a semiconductor structure according to an exemplary embodiment of this application;

[0026] Figure 2This is a schematic diagram of the substrate of a semiconductor structure according to an exemplary embodiment of this application;

[0027] Figures 3a to 3b These are schematic diagrams illustrating the formation of an initial filling layer in a semiconductor structure according to different exemplary embodiments of this application;

[0028] Figures 4a to 4b Based on Figures 3a to 3b A schematic diagram illustrating the formation of the initial fill layer in the process;

[0029] Figures 4c to 4f This is a schematic diagram illustrating the direct formation of a filling layer within a groove according to an exemplary embodiment of this application;

[0030] Figure 4g This is the structure of the first filling particle according to an exemplary embodiment of this application;

[0031] Figure 4h This is the structure of the second filling particle according to an exemplary embodiment of this application;

[0032] Figures 5a to 5c These are schematic diagrams illustrating the formation of an initial dielectric layer using dielectric structures according to different exemplary embodiments of this application;

[0033] Figures 6a to 6d This is a schematic diagram showing the shrinkage of the filler layer volume due to the dielectric structure according to different exemplary embodiments of this application;

[0034] Figure 6e It is a structure in which the dielectric structure of the exemplary embodiment of this application forms the first filling particle after shrinkage;

[0035] Figure 6f It is a structure in which the dielectric structure of the exemplary embodiment of this application forms a shrunken second filling particle;

[0036] Figure 7 This is a schematic diagram of the dielectric structure after the shrinkage of the filler layer is removed according to an exemplary embodiment of this application;

[0037] Figures 8a to 8e Based on Figures 6a to 7 as well as Figure 5c A schematic diagram of a dielectric structure forming a dielectric layer in an exemplary embodiment;

[0038] Figures 9a to 9d Based on Figures 8a to 8c as well as Figure 8e A schematic diagram of dielectric layer planarization of a dielectric structure in an exemplary embodiment;

[0039] Figures 10a to 10e These are partial structural schematic diagrams of the dielectric structure according to different exemplary embodiments of this application; and

[0040] Figure 11 This is a schematic diagram of a semiconductor device according to an exemplary embodiment of the fundamental application. Detailed Implementation

[0041] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0042] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features, especially not any order of precedence. Therefore, without departing from the teachings of this application, the first filling particle discussed herein may also be referred to as the second filling particle, and vice versa.

[0043] In this specification, references to "one embodiment," "implementation," "example embodiment," "some embodiments," etc., indicate that the described embodiment may include a specific feature, structure, or characteristic; however, each embodiment may not necessarily include that specific feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in connection with an embodiment, whether explicitly stated or not, implementing that feature, structure, or characteristic in conjunction with other embodiments will be within the knowledge of those skilled in the art.

[0044] In the accompanying drawings, the thickness, dimensions, and shapes of the components have been slightly adjusted for ease of illustration. The drawings are for illustrative purposes only and are not drawn to scale. For example, the thickness of the dielectric layer depicted in the drawings in this application is not proportional to actual production. Terms such as “approximately,” “about,” and similar expressions used herein are used as terms of approximation, not as terms of degree, and are intended to illustrate inherent deviations in measured or calculated values ​​that will be recognized by those skilled in the art.

[0045] It should be understood that expressions such as "comprising," "including," "having," "containing," and / or "comprising" are open-ended rather than closed-ended expressions in this specification, indicating the presence of the stated features, elements, and / or components, but not excluding the presence of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not just individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplarily" is intended to refer to examples or illustrations.

[0046] It should also be understood that the meanings of “above,” “above,” and “on top” in this disclosure should be interpreted in the broadest sense, such that “above” means not only “directly on something” but also includes “on something” with an intermediate feature or layer therebetween, and that “above” or “on top” means not only “above” or “on top” something but also includes “above” or “on top” something without an intermediate feature or layer therebetween (i.e., directly on something).

[0047] Unless otherwise specified, all terms used herein (including engineering and technical terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that, unless expressly stated herein, terms defined in common dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or overly formalized meaning.

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Furthermore, unless explicitly limited or contradicted by the context, the specific steps included in the methods described in this application are not limited to the order in which they are described, but can be performed in any order or in parallel. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0049] The features, principles and other aspects of this application are described in detail below.

[0050] To meet the demands of the integrated circuit industry, the electrical performance requirements of on-chip electronic circuits have become increasingly stringent in recent years. The inventors of this application have discovered that as integrated circuit dimensions shrink, the RC delay caused by inter-line and inter-layer parasitic capacitances, as well as crosstalk noise and heat dissipation issues, are increasingly constraining very large-scale integrated circuits. The RC delay can be limited using formula (1):

[0051] RC =2 ρεε0(4 L 2 / P 2 + L 2 / T 2 (1)

[0052] in, ρ The resistivity of the metal, P The slope of the metal wire; ε 0 is the dielectric constant of vacuum. ε is the relative permittivity of the inter-line insulation layer; T is the thickness of the metal wire.

[0053] As can be seen from formula (1), reducing the resistivity of the metal ρ and reduce the relative permittivity of the inter-line insulation layer ε All of these are beneficial for reducing RC delay. Therefore, the above problems can be improved in the following three ways, for example. First, use resistivity ρ The first step is to replace aluminum wires with lower dielectric constants (e.g., copper wires) as interconnecting metal wires; the second is to develop materials with lower dielectric constants to replace silicon dioxide materials; and the third is to introduce porous structures into the materials to further reduce the dielectric constant.

[0054] This application proposes a dielectric structure and its manufacturing method, which can at least partially improve or solve the above-mentioned problems. According to this application, by introducing a porous structure into the substrate material, the dielectric constant of the substrate material can be reduced, thereby reducing the RC delay in the circuit. Simultaneously, the RC delay caused by inter-line / inter-layer parasitic capacitance can be reduced without significantly increasing costs, which is beneficial for the miniaturization of integrated circuits.

[0055] Figure 1 This is a flowchart of a method 1000 for preparing a dielectric structure according to an embodiment of this application. For example... Figure 1 As shown, this application provides a method 1000 for preparing a dielectric structure, comprising:

[0056] Step S1100: Forming a substrate with grooves;

[0057] Step S1200: Forming a filling layer within the groove, wherein the filling layer fills at least a portion of the space within the groove; and

[0058] Step S1300 involves shrinking the volume of the filling layer to release at least a portion of the space in the groove that was filled.

[0059] It should be understood that the steps shown in method 1000 are not exclusive, and other steps may be performed before, after, or between any of the steps shown. Furthermore, some of the steps shown may be performed simultaneously or in a sequence different from the steps described. Figure 1 The execution is performed in the order shown.

[0060] Figure 2 Figure 9 is a schematic diagram of the fabrication method 1000 of the dielectric structure according to an embodiment of this application. It should be noted that the dielectric structure described in this application context can be applied to various circuit structures requiring reduced RC delay. As an example, the dielectric structure of this application can be applied to a three-dimensional memory. The following is in conjunction with... Figure 2 The above steps S1100 to S1300 are further described in Figure 9.

[0061] Step S1100: A groove is formed in the substrate.

[0062] Figure 2 This is a schematic diagram of the substrate of a dielectric structure according to an exemplary embodiment of this application. For example... Figure 2 As shown, a groove 111 can be formed in the substrate 110. Figure 2 In the embodiment shown, the groove 111 is in xz On the plane and in xy The projected shapes on the plane are all rectangles. However, those skilled in the art will understand that the grooves are... xz On the plane and in xy The projected shape on the plane can be either regular or irregular. This application does not impose any restrictions on this. The groove 111 can be formed on the substrate 110 using an etching process.

[0063] Exemplarily, the substrate 110 may be made of semiconductor materials, such as single-crystal silicon, polycrystalline silicon, silicon-germanium (SiGe), germanium (Ge), silicon-on-insulator (SOI), germanium-on-insulator (GOI), gallium arsenide (GaAs), gallium nitride (GaN), silicon carbide (SiC), III-V compound semiconductors, or any combination thereof. It should be understood that the material of the substrate 110 is merely illustrative, and those skilled in the art may select other suitable materials depending on the specific implementation; this application does not impose any limitations on this.

[0064] Step S1200: A filling layer is formed in the groove, wherein the filling layer fills at least a portion of the space in the groove.

[0065] Figures 3a to 3b This is a schematic diagram illustrating the formation of an initial filling layer using dielectric structures according to different exemplary embodiments of this application. For example... Figure 3aAs shown, an initial filling layer 121 can be formed within the groove 111. The initial filling layer 121 is composed of a swellable material 161. It should be noted that the swellable material described in the context of this application has swelling properties, being in an expanded state when absorbing a solution and in a contracted state when not absorbing a solution. The swellable material 161 absorbs the solution and completely fills the space of the groove 111 in a swollen state. In some embodiments, the swellable material 161 also covers the upper surface of the substrate 110. The swellable material 161 can be formed within the groove 111 and on the upper surface of the substrate 110 by a coating process. In other embodiments, the swellable material 161 in a swollen state may only fill a portion of the groove 111.

[0066] Exemplarily, the swelling material 161 comprises a polymeric material, such as phenolic resin, which absorbs an ethanol solution and swells to fill the groove 111. The process of forming the phenolic resin may include reacting resorcinol with formaldehyde in an ammonia atmosphere to generate the phenolic resin, after which an ethanol solution can be used as a swelling agent to swell the phenolic resin ester. In other embodiments, the swelling material 161 may also be polyvinyl alcohol, polyacrylamide, or agar, which absorbs an aqueous solution and swells to fill the groove 111.

[0067] like Figure 3b As shown, in some embodiments, an initial filling layer 151 may be formed within the groove 111. The initial filling layer 151 comprises a shrinkable material. This shrinkable material completely fills the space of the groove 111 and covers the upper surface of the substrate 110. It should be noted that the shrinkable material described in this application context can be either solvent-containing or solvent-free. When the shrinkable material contains a solvent, its volume will decrease after at least a portion of the solvent is removed; when the shrinkable material does not contain a solvent, its volume will also decrease after undergoing some processing, exemplarily, such processing, which may be heat treatment, and the shrinkable material volume decreases after cooling and curing.

[0068] Exemplarily, a method for forming a shrinkable material within the groove 111 includes dissolving a first material in a first solvent and spin-coating it into the groove 111 using a spin-dip coating (SOD) process. In this embodiment, the shrinkable material comprises a solution consisting of the first material and the first solvent. The first solvent can then be removed by a heat treatment process at a temperature, for example, between 100°C and 1000°C. In other embodiments, the shrinkable material can be directly deposited into the groove 111 using a flowable chemical vapor deposition (FCVD) process. In this embodiment, the shrinkable material can be the first material. Exemplarily, the first material comprises silicon dioxide, and the first solvent comprises n-butyl ether. The n-butyl ether can be removed at 950°C, and the density of the silicon dioxide can be increased (i.e., the overall volume shrinks) by high temperature, thereby forming partial voids within the groove 111. When the shrinkable material contains the first solvent, the shrinkable material can be silicon dioxide dissolved in n-butyl ether; when the shrinkable material does not contain the first solvent, it can be silicon dioxide. When using the flowable chemical vapor deposition (FCVD) process, the shrinkable material does not contain solvent, and its operating temperature is, for example, 65°C, and its operating pressure is, for example, 200 torr.

[0069] Next, a fill layer can be formed based on the initial fill layer. Figure 4a Based on Figure 3a A schematic diagram illustrating the formation of the initial fill layer in the diagram. Figure 4b Based on Figure 3b A schematic diagram illustrating the formation of the initial fill layer in [the diagram]. For example... Figure 4a As shown, the portion of the initial filler layer 121 located on the substrate 110 can be removed, as well as the portion of the initial filler layer 121 located within the groove 111 and connected to the initial filler layer 121 on the substrate 110. The remaining portion of the initial filler layer 121 forms the filler layer 120. According to another embodiment (not shown), only the portion of the initial filler layer 121 located on the substrate 110 can be removed, and the remaining portion of the initial filler layer 121 located within the groove 111 forms the filler layer 120. Exemplarily, the material of the filler layer 120 is a swelled phenolic resin, and the aforementioned portion of the initial filler layer 121 can be removed by means of ethanol dissolution or dry etching to form the filler layer 120.

[0070] like Figure 4bAs shown, in some embodiments, the portion of the initial filler layer 151 located on the substrate 110 may be removed, and the portion of the initial filler layer 151 located within the groove 111 and connected to the initial filler layer 151 located on the substrate 110 may also be removed, with the remaining portion of the initial filler layer 151 forming the filler layer 150. According to another embodiment (not shown), only the portion of the initial filler layer 151 located on the substrate 110 may be removed, with the remaining portion of the initial filler layer 151 located within the groove 111 forming the filler layer 120. Exemplarily, the filler layer 150 is made of a shrinkable material, and the aforementioned portion of the initial filler layer 151 can be removed by an etching process to form the filler layer 150.

[0071] exist Figures 3a to 4b In the illustrated embodiment, an initial filler layer is first formed, and then a portion of the initial filler layer is removed to form the filler layer. However, those skilled in the art will understand that a filler layer filling at least a portion of the groove 111 can also be formed directly within the groove 111 using a swellable or shrinkable material through a suitable process.

[0072] Figures 4c to 4f A schematic diagram is shown of a filling layer directly formed in a groove 111 according to some exemplary embodiments of the present application.

[0073] like Figure 4c As shown, in some embodiments, a filling layer 180 can be formed directly within the groove 111, and the filling layer 180 can be composed of a plurality of first filling particles 181. Figure 4c In the embodiment shown, the filler layer 180 completely fills the groove 111. For example... Figure 4d As shown, according to another embodiment, the filling layer 180 may fill only a portion of the groove 111. Figure 4g The structure of a first filler particle 181 according to an exemplary embodiment of this application is illustrated schematically. Reference Figure 4g The first filler particle 181 includes a swellable material 161 covered by a mesoporous material 170, wherein the swellable material 161 may be in a swellable state.

[0074] Exemplarily, a method for forming the first filler particle 181 includes first forming a swellable material 161 that has absorbed a solution, then coating the surface of the swellable material 161 in a swellable state with a mesoporous material 170; and finally dissolving it in a second solvent and coating it into the groove 111. Exemplarily, the swellable material 161 includes phenolic resin, the mesoporous material 170 includes mesoporous silica, and the second solvent includes deionized water. The first filler particle 181 may be a phenolic resin microsphere coated with mesoporous silica, having a core-shell structure in its three-dimensional space, with the mesoporous silica forming the outer shell and the phenolic resin forming the core. The phenolic resin can absorb the ethanol solution, swell, and completely fill the space within the mesoporous silica shell.

[0075] like Figure 4e As shown, in some other embodiments, the filler layer 180 may consist of a plurality of second filler particles 182. Figure 4e and Figure 4f These represent two states where the second filling particle 182 fills the groove 111. Figure 4e In the embodiment shown, a plurality of second filler particles 182 completely fill the groove 111. Figure 4f In the embodiment shown, the plurality of second filling particles 182 fill only a portion of the groove 111. Figure 4h The structure of a second filling particle according to an exemplary embodiment of this application is illustrated schematically. Reference Figure 4h The second filler particle 182 includes a shrinkable material 162 coated with a mesoporous material 170, wherein the shrinkage of the mesoporous material 170 is less than that of the shrinkable material 162. It should be noted that the shrinkage magnitude described in this application context is a comparison of the shrinkage of different materials under the same operating conditions, such as 25°C and 1 standard atmosphere.

[0076] For example, the mesoporous material 170 includes mesoporous silica, the shrinkable material 162 includes alumina ceramic, carbon fiber, or silicon-carbon composite material, and the second filler particle 182 may be alumina ceramic microspheres, carbon fiber microspheres, or silicon-carbon composite microspheres coated with mesoporous silica. All of these particles have a core-shell structure, with the mesoporous silica forming the outer shell and the alumina ceramic / carbon fiber / silicon-carbon composite material forming the core. The alumina ceramic / carbon fiber / silicon-carbon composite material core completely fills the space within the mesoporous silica shell.

[0077] Figures 5a to 5cThis is a schematic diagram illustrating the formation of an initial dielectric layer according to different exemplary embodiments of the present application. It should be noted that embodiments of the present application also include forming an initial dielectric layer 130 based on the exemplary embodiments mentioned above where the filling layers 120, 150, and 180 completely fill the groove 111. The initial dielectric layer 130 is located only on the substrate 110 and does not extend into the groove 111. Because it is related to… Figures 5a to 5c The principle of initial dielectric layer formation is the same in the exemplary embodiments, and will not be repeated here. Those skilled in the art can refer to the following description. Figures 5a to 5c The exemplary embodiments provide a detailed description of the initial dielectric layer to obtain the process of forming the initial dielectric layer in embodiments where the groove 111 is completely filled by the filling layers 120, 150 and 180 respectively, and the material of the initial dielectric layer in the corresponding scheme.

[0078] like Figure 5a As shown, an initial dielectric layer 130 can be formed on the filler layer 120 and the substrate 110. The initial dielectric layer 130 covers the upper surface of the substrate 110 and extends to the upper surface of the filler layer 120 within the groove 111.

[0079] like Figure 5b As shown, in some embodiments, an initial dielectric layer 130 may be formed on the filler layer 150 and the substrate 110. The initial dielectric layer 130 covers the upper surface of the substrate 110 and extends to the upper surface of the filler layer 150 within the recess 111. The initial dielectric layer 130 has mesopores, and the material of the initial dielectric layer 130 includes mesoporous silicon dioxide.

[0080] like Figure 5c As shown, in some embodiments, an initial dielectric layer 130 may be formed on the filler layer 180 and the substrate 110. The initial dielectric layer 130 covers the upper surface of the substrate 110 and extends to the upper surface of the filler layer 180 within the groove 111. The initial dielectric layer 130 has mesopores, and the material of the initial dielectric layer 130 is, for example, mesoporous silicon dioxide.

[0081] exist Figures 5a to 5c In the exemplary embodiment shown, the initial dielectric layer 130 has mesopores, and the material of the initial dielectric layer 130 includes mesoporous silica. The process for forming mesoporous silica includes reacting tetraethyl orthosilicate (TEOS) with a cationic surfactant (CTAB) dissolved in a hexane solution to generate mesoporous silica.

[0082] Step S1300 involves shrinking the volume of the filling layer to release at least a portion of the space in the groove that was filled.

[0083] Figures 6a to 6dThis is a schematic diagram illustrating the volume shrinkage of the filling layer according to different exemplary embodiments of the present application. It should be noted that the embodiments of the present application may include shrinking the volume of the filling layer based on an embodiment where the initial dielectric layer is only located on the substrate 110 (i.e., the filling layer completely fills the groove 111), or shrinking the volume of the filling layer based on an embodiment where the initial dielectric layer is located on the substrate and extends into the groove 111 (i.e., the filling layer only fills a portion of the groove 111). Since the location and state of the initial dielectric layer are not the focus of the description in step S1300, to avoid redundancy, the following only describes the embodiments of the present application. Cause the filler layer volume to shrink Some implementation methods are described in detail by way of example.

[0084] like Figure 6a As shown, at least a portion of the solution in the swollen filler layer 120 can be removed, causing its volume to shrink and form a shrunken filler layer 120', thereby releasing at least a portion of the space in the groove 111 occupied by the swollen filler layer 120, the released space being the void 140. Exemplarily, a method for removing at least a portion of the solution in the swollen filler layer 120 includes flushing the filler layer 120 with gas. For example, ethanol gas can be used to flush the filler layer 120 to remove at least a portion of the solution and cause its volume to shrink. The operating temperature (i.e., the ambient temperature under operating conditions) during ethanol gas flushing of the filler layer 120 is, for example, 75°C, and the operating pressure (i.e., the ambient pressure under operating conditions) is, for example, 500 torr.

[0085] After the shrinking filler layer 120' is formed, the lower surface of the portion of the initial dielectric layer 130 located within the groove 111 is suspended, and the gap 140 is located between the initial dielectric layer 130 and the shrinking filler layer 120'.

[0086] In other embodiments, after forming the shrunken filler layer 120', the shrunken filler layer 120' is completely removed to further release the space occupied by the recess 111 (see reference). Figure 7 (As shown). Combined Figure 5a and Figure 7 As shown, the space released after the filler layer 120 is completely removed is the void 140. Exemplarily, the shrunken filler layer 120' can be treated by a dry oxygen thermal oxidation process to completely remove the shrunken filler layer 120'. The temperature of the dry oxygen thermal oxidation process includes, for example, 900°C to 1000°C.

[0087] like Figure 6bAs shown, in some embodiments, the filler layer 150 may include a shrinkable material that allows the volume of the filler layer 150 to shrink to form a shrunken filler layer 150', thereby releasing at least a portion of the space in the groove 111 occupied by the filler layer 150, the released space being the void 140. Exemplarily, a method for forming the shrunken filler layer 150' includes applying the filler layer 150 dissolved in a first solvent to the groove 111 using a spin-coating (SOD) process, followed by removing the first solvent using a heat treatment process to shrink the filler layer 150 into the filler layer 150'. The material of the filler layer 150 is, for example, silicon dioxide, the first solvent is, for example, n-butyl ether, and the temperature of the heat treatment process is, for example, 900°C to 1000°C. In other embodiments, a method for forming the shrunken filler layer 150' includes depositing the filler layer 150 into the groove 111 using a flowable chemical vapor deposition (FCVD) process, followed by a heat treatment process that heats and then cools to solidify, forming the shrunken filler layer 150'.

[0088] like Figure 6c As shown, in some other embodiments, the filler layer 180 may consist of a plurality of first filler particles 181, the first filler particles 181 including a swellable material 161 covered by a mesoporous material 170. Figure 6e An exemplary embodiment of the present application illustrates the structure of a first filler particle 181' formed after shrinkage. (In conjunction with...) Figure 4g and Figure 6e As shown, the swelling material 161 in the first filler particle 181 can be shrunk in volume to form a shrunk first filler particle 181'. The method includes at least partially removing the solution absorbed in the swelling material 161 to cause the volume of the swelling material 161 to shrink and form the shrunk swelling material 161'. The space released by the volume shrinkage of the swelling material 161 is the first gap 141.

[0089] like Figure 6d As shown, in some other embodiments, the filler layer 180 may consist of a plurality of second filler particles 182, the second filler particles 182 including shrinkable material 162 covered by mesoporous material 170. Figure 6f An exemplary embodiment of the present application illustrates the structure of a shrunken second filler particle 182' formed according to an exemplary embodiment of this application. (Combined with...) Figure 4h and Figure 6fAs shown, the shrinkable material 162 in the second filler particle 182 can be shrunk in volume to form a shrunk second filler particle 182'. The method includes heat-treating the shrinkable material 162 and the mesoporous material 170, followed by cooling and curing. Exemplarily, the heat treatment temperature can be between 900°C and 1000°C. The volume shrinkage of the shrinkable material 162 forms the shrunk shrinkable material 162'. It is understood that because the shrinkage of the shrinkable material 162 is greater than that of the mesoporous material 170, after cooling and curing, a first gap 141 is formed between the mesoporous material 170 and the shrunk shrinkable material 162'.

[0090] It should be noted that the step of shrinking the volume of the first filler particle 181 can be performed before the step of dissolving the swellable material 161 coated with the mesoporous material 170 in the second solvent, or after the step of coating the swellable material 161 coated with the mesoporous material 170 into the groove 111. Similarly, the step of shrinking the volume of the second filler particle 182 can be performed before the step of coating the shrinkable material 162 coated with the mesoporous material 170 into the groove 111, or after the step of coating it into the groove 111.

[0091] Figures 8a to 8e Based on Figures 6a to 7 as well as Figure 5c A schematic diagram of a dielectric structure forming a dielectric layer in an exemplary embodiment. Specifically, in conjunction with... Figure 6a and Figure 8a , Figure 7 and Figure 8b or Figure 6b and Figure 8c As shown, the initial dielectric layer 130 can be transformed into a dielectric layer 130'. The density of the initial dielectric layer 130 is less than the density of the dielectric layer 130'. Exemplarily, the initial dielectric layer 130 can be transformed into a dielectric layer 130' by a hydrothermal oxidation process. The initial dielectric layer 130 comprises mesoporous silica, which is transformed into denser silica (i.e., transformed into dielectric layer 130') by a hydrothermal oxidation process at a temperature range of 500°C to 700°C.

[0092] Combination Figures 6c to 6d and Figure 8d As shown, in some embodiments, a portion of the mesoporous material 170 may be shrunk to form a dielectric layer 130'. Exemplarily, the mesoporous material 170 located in the upper portion of the groove 111 can be oxidized into the dielectric layer 130' using a steam thermal oxidation process. The density of the dielectric layer 130' is greater than the density of the mesoporous material 170, which comprises mesoporous silica, and the dielectric layer 130' comprises silica. The steam thermal oxidation temperature can be from 500°C to 700°C.

[0093] Combination Figure 5c and Figure 8e As shown, in some embodiments, an initial dielectric layer 130 is formed on the filler layer 180. The initial dielectric layer 130 and a portion of the mesoporous material 170 in contact with the initial dielectric layer 130 can be combined to form a dielectric layer 130'. The densities of both the initial dielectric layer 130 and the mesoporous material 170 are less than the density of the dielectric layer 130'. Exemplarily, the initial dielectric layer 130 and the mesoporous material 170 can be processed by a hydrothermal oxidation process to form the dielectric layer 130'. The initial dielectric layer 130 and the mesoporous material 170, for example, both comprise mesoporous silica, which is converted into denser silica (i.e., converted into dielectric layer 130') by a hydrothermal oxidation process at a temperature range of 500°C to 700°C.

[0094] It is understandable that forming a relatively dense medium layer 130' at the top of the groove 111 helps to ensure the stability of the space formed after the volume shrinkage of the filling layer / filling particles, and avoids the collapse of the space in subsequent processes.

[0095] Figures 9a to 9d Based on Figures 8a to 8c as well as Figure 8e A schematic diagram of the dielectric layer planarization of the dielectric structure in an exemplary embodiment. (Combined with...) Figure 8a and Figure 9a , Figure 8b and Figure 9b , Figure 8c and Figure 9c Or combination Figure 8e and Figure 9d As shown, after converting the initial dielectric layer 130 into dielectric layer 130', the process also includes removing the portion of dielectric layer 130' located outside the groove 111 and smoothing the surface of the retained portion of dielectric layer 130' so that it is flush with the upper surface of the substrate 110.

[0096] exist Figure 9a In the exemplary embodiment shown, the retained portion of the dielectric layer 130' forms a surrounding space with the substrate 110, surrounding the shrunken filler layer 120' and the void 140; Figure 9b In the exemplary embodiment shown, the surrounding space formed by the retained portion of the dielectric layer 130' and the substrate 110 only surrounds the void 140; Figure 9c In the exemplary embodiment shown, the surrounding space formed by the retained portion of the dielectric layer 130' and the substrate 110 surrounds the shrunken filler layer 150' and the void 140. Figure 9d In the exemplary embodiment shown, the space formed by the retained portion of the dielectric layer 130' and the substrate 110 surrounds the shrunken filler layer 180'.

[0097] In some embodiments, the shrunken filler layer 180' may consist of a plurality of shrunken first filler particles 181' (see reference). Figure 6e The first filler particle 181' after shrinkage has a first gap 141. A second gap 142 also exists between each pair of first filler particles 181' after shrinkage. The first gap 141 and the second gap 142 together form a void 140.

[0098] In other embodiments, the shrunken filler layer 180' consists of a plurality of shrunken second filler particles 182' (see reference). Figure 6f The shrunken second filler particle 182' has a first gap 141. A second gap 142 also exists between each pair of shrunken second filler particles 182'. The first gap 141 and the second gap 142 together form a void 140.

[0099] Understandably, the presence of the 140 gap is equivalent to introducing a porous structure into the material, which helps to increase the dielectric constant of the material and reduce the RC delay in the circuit.

[0100] For example, the portion of the dielectric layer 130' located outside the groove 111 can be removed by a process such as chemical mechanical polishing.

[0101] Another aspect of this application provides a dielectric structure 100, which can be prepared using the preparation method described in any of the above embodiments.

[0102] Figures 10a to 10e These are partial structural schematic diagrams of dielectric structures according to different exemplary embodiments of this application. (See Figures 10 to...) Figure 10e As shown, the dielectric structure 100 includes a substrate 110 and a dielectric layer 130'. The substrate 110 may have a groove 111, and the dielectric layer 130' is suspended at the top of the groove 111, contacting the substrate 110 and closing the top of the groove 111. Exemplarily, the groove 111 has a void 140.

[0103] It should be noted that the term "suspension" above describes the state in which the medium layer 130' exists at the top of the groove 111. The medium layer 130' can contact the substrate 110 through the sidewall. "Suspension" is defined as the lower surface of the medium layer 130' (facing...). y At least half of the area of ​​the surface on the opposite side of the dielectric layer 130' is suspended, meaning the ratio of the area of ​​the suspended portion to the total area of ​​the lower surface exceeds 1 / 2. This suspended portion may include multiple discontinuous sections or only a single continuous section. Figure 10aAs shown, in some exemplary embodiments, the dielectric structure 100 may further include a filler layer 120' located within the groove 111 and filling only a portion of the groove 111. Exemplarily, the portion of the groove 111 filled by the filler layer 120' is less than half the total space of the groove 111. A gap 140 is located between the filler layer 120' and the dielectric layer 130'. Exemplarily, the dielectric layer 130' is made of silicon dioxide, and the filler layer 120' is made of phenolic resin, which is not in contact with the silicon dioxide.

[0104] like Figure 10c As shown, in some other exemplary embodiments, the dielectric structure 100 may further include a filler layer 150' located within the groove 111 and filling only a portion of the groove 111. Exemplarily, the portion of the groove 111 filled by the filler layer 150' is less than half the total space of the groove 111. A gap 140 is located between the filler layer 150' and the dielectric layer 130'. Exemplarily, the filler layer 150' is made of cured silicon dioxide. Figures 10a to 10c In the embodiment shown, the dielectric layer 130' is suspended at the top of the groove 111, with its lower surface completely suspended.

[0105] like Figure 10d As shown, in some further exemplary embodiments, the dielectric structure 100 may also include a filling layer 180' located within the groove 111 and filling only a portion of the groove 111. The filling layer 180' is composed of a plurality of first filling particles 181', which may be swellable materials 161' coated with mesoporous material 170. The mesoporous material 170 forms a shell structure that completely covers the core structure formed by the swellable material 161'. A first gap 141 exists between the core structure formed by the swellable material 161' and the shell structure formed by the mesoporous material 170; a second gap 142 also exists between pairs of first filling particles 181'. The first gap 141 and the second gap 142 together constitute a void 140.

[0106] like Figure 10e As shown, in some further exemplary embodiments, the filling layer 180' may also be composed of a plurality of second filling particles 182', wherein the second filling particles 182' may be shrinkable materials 162' coated with mesoporous material 170, and the mesoporous material 170 forms a shell structure that completely covers the shrinkable material 162'. A first gap 141 exists between the shrinkable material 162' and the shell formed by the mesoporous material 170; a second gap 142 also exists between each pair of second filling particles 182'. The first gap 141 and the second gap 142 together constitute a void 140.

[0107] Understandably, the presence of the 140 gap is equivalent to introducing a porous structure into the material, which helps to increase the dielectric constant of the material and reduce the RC delay in the circuit.

[0108] according to Figures 10d to 10e In the illustrated embodiment, at least a portion of the dielectric layer 130' may be formed by shrinking the mesoporous material 170. The density of the mesoporous material 170 is less than the density of the dielectric layer 130'. Exemplarily, the mesoporous material 170 is mesoporous silicon dioxide, and the dielectric layer 130' is made of silicon dioxide.

[0109] For example, the substrate 110 may be made of semiconductor materials, such as single-crystal silicon, polycrystalline silicon, silicon-germanium (SiGe), germanium (Ge), silicon-on-insulator (SOI), germanium-on-insulator (GOI), gallium arsenide (GaAs), gallium nitride (GaN), silicon carbide (SiC), III-V compound semiconductors, or any combination thereof.

[0110] It should be noted that the substrate 110 may also be made of non-semiconductor materials. The substrate 110 formed of non-semiconductor materials has the porous structure (voids 140) described above and can be applied in different scenarios. For example, the substrate 110 may be made of a metallic material (including tungsten). The porous structure in this material increases the relative permittivity of the substrate 110, which can be applied in metal interconnect layers and reduce the RC delay between metal interconnects.

[0111] Another aspect of this application provides a semiconductor device 200. The semiconductor device 200 may include the dielectric structure 100 and the first structure 210 in any of the embodiments described above, wherein the first structure 210 is connected to the dielectric structure 100.

[0112] refer to Figure 11 The semiconductor device 200 is a DRAM memory, and the first structure 210 can be a DRAM cell disposed on the dielectric structure 100. The DRAM cell can be any suitable configuration, such as a 2T1C cell, a 3T1C cell, etc.

[0113] In some other examples, the semiconductor device 200 is a memory (not shown) with an Xtacking architecture, which may include multiple wafers bonded to each other, at least one of the wafers being formed by the first structure 210 and the dielectric structure 100.

[0114] As an example, the semiconductor device 200 has a gap 140. The presence of the gap 140 is beneficial to increasing the dielectric constant of the material and reducing the RC delay in the circuit.

[0115] It should be noted that the semiconductor device 200 may also be other types of storage devices or storage equipment. The context of this application only provides an exemplary description of the semiconductor device 200 and is not intended to limit its specific type or specific use case.

[0116] The above description is merely an illustration of the embodiments of this application and the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the technical concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method of producing a dielectric structure, characterized by, The method comprises: forming a recess in a substrate; forming a fill layer in the recess, wherein the fill layer fills at least part of the space of the recess, and the fill layer comprises a swellable material or a shrinkable material; and shrinking the volume of the fill layer to release at least part of the space filled by the fill layer.

2. The method of claim 1, wherein, Before shrinking the volume of the fill layer, the method further comprises: forming an initial medium layer on the fill layer and on the substrate, wherein the initial medium layer has mesopores.

3. The method of claim 2, wherein, The fill layer comprises the swellable material, which absorbs a solution and fills at least part of the space of the recess in a swollen state, and The method of shrinking the volume of the fill layer comprises: at least partially removing the solution.

4. The method of claim 3, wherein, After shrinking the volume of the fill layer, the method further comprises: removing the fill layer; and converting the initial medium layer into a medium layer, wherein the medium layer has a density greater than that of the initial medium layer.

5. The method of claim 4, wherein, The method of removing the fill layer comprises removing the fill layer by a dry-oxygen thermal oxidation process, and The method of converting the initial medium layer into the medium layer comprises converting the initial medium layer into the medium layer by a water-vapor thermal oxidation process.

6. The method of claim 1, wherein, The method of forming the shrinkable material in the recess comprises dissolving a first material in a first solvent and coating into the recess by a spin-coating process, and the method of shrinking the volume of the shrinkable material comprises at least partially removing the first solvent; or The method of forming the shrinkable material in the recess comprises depositing the shrinkable material into the recess by a flowable chemical vapor deposition process, and the method of shrinking the volume of the shrinkable material comprises heating the shrinkable material and solidifying by cooling, wherein the shrinkable material comprises the first material.

7. The method of claim 3, wherein, After shrinking the volume of the fill layer, the method further comprises: converting the initial medium layer into a medium layer, wherein the initial medium layer has a density less than that of the medium layer.

8. The method of claim 1, wherein, The method of forming the fill layer comprises: forming an initial fill layer in the recess and on the substrate; and removing the part of the initial fill layer on the substrate and the part of the initial fill layer in the recess and connected to the part of the initial fill layer on the substrate, wherein the unremoved part of the initial fill layer forms the fill layer.

9. The method of claim 1, wherein, The fill layer comprises first fill particles, each of which comprises the swellable material coated by mesoporous material.

10. The method of claim 9, wherein, The method of forming the first fill particles in the recess comprises: forming the swellable material absorbing a solution; coating mesoporous material on the surface of the swellable material; and dissolving the swellable material coated by mesoporous material in a second solvent and coating into the recess.

11. The method of claim 10, wherein, The method of shrinking the volume of the first fill particles comprises: at least partially removing the solution, wherein the step of shrinking the volume of the first fill particles is performed before the step of dissolving the swellable material coated by mesoporous material in the second solvent, or The step of shrinking the volume of the first filler particles is performed after the step of coating the swellable material with the mesoporous material into the recess.

12. The method of claim 1, wherein, The filler layer includes second filler particles, each of the second filler particles including the shrinkable material coated with the mesoporous material, wherein the shrinkability of the mesoporous material is less than the shrinkability of the shrinkable material.

13. The method of claim 10 or 12, wherein, After shrinking the volume of the filler layer, the method further includes: converting the mesoporous material in the filler layer on top of the recess into a dielectric layer, wherein the dielectric layer has a density greater than the density of the mesoporous material.

14. The method of claim 9 or 12, wherein, Before shrinking the volume of the filler layer, the method further includes forming an initial dielectric layer on the filler layer and on the substrate, wherein the initial dielectric layer has mesopores; and After shrinking the volume of the filler layer, the method further includes converting the mesoporous material in the filler layer on top of the recess and the initial dielectric layer into a dielectric layer, wherein the dielectric layer has a density greater than the density of the mesoporous material.

15. A dielectric structure, characterized by, The dielectric structure includes: a substrate having a recess; and a dielectric layer suspended on top of the recess and in contact with the substrate to close the recess on the top, wherein the recess has a void therein; and a filler layer located in the recess and filling at least a portion of the recess, the filler layer including a swellable material or a shrinkable material.

16. The dielectric structure of claim 15, wherein, At least half of the area on the surface of the dielectric layer facing the bottom of the recess is suspended.

17. The dielectric structure of claim 15, wherein, The filler layer includes first filler particles, each of the first filler particles including a swellable material coated with a mesoporous material, wherein the void is located between the mesoporous material and the swellable material, and between two of the first filler particles; or The filler layer includes second filler particles, each of the second filler particles including the shrinkable material coated with a mesoporous material, wherein the void is located between the mesoporous material and the shrinkable material, and between two of the second filler particles.

18. A semiconductor device, comprising: the dielectric structure of any one of claims 15-17; and a first structure connected to the dielectric structure. ​

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