Semiconductor structure and method of manufacturing the same

Abstract

This invention relates to a semiconductor structure and its fabrication method. The semiconductor structure includes: an electrode capping layer located on a substrate; a first conductive structure located on the upper surface of the electrode capping layer; and a contact structure including a first contact layer and a second contact layer, wherein the first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer; wherein the lower surface of the contact structure is not lower than the lower surface of the electrode capping layer, and the resistivity of the first conductive structure is not greater than the resistivity of the contact structure and not greater than the resistivity of the electrode capping layer. This increases the contact area between the contact structure and the electrode capping layer while avoiding the formation of voids in the contact structure, thereby reducing the contact resistance and the bulk resistance between the contact structure and the capacitor structure below the electrode capping layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of integrated circuits, and in particular to a semiconductor structure and a preparation method thereof. BACKGROUND

[0002] In a typical preparation process of a metal interconnection layer of a dynamic random access memory, a via reaches into an electrode cover layer to reduce the contact resistance between the contact structure in the via and the electrode cover layer. However, when the via is too large, the load effect or the contact structure recess problem is prone to occur in a chemical polishing process due to the difference from adjacent pattern structures; when the via is too small, a void is prone to occur in the contact structure, resulting in a sharp increase in the contact resistance. SUMMARY

[0003] Therefore, it is necessary to provide a semiconductor structure and a preparation method thereof to solve the problems in the prior art.

[0004] To achieve the above-mentioned purpose, in one aspect, the present application provides a semiconductor structure, comprising:

[0005] an electrode cover layer located on a substrate;

[0006] a first conductive structure located on an upper surface of the electrode cover layer;

[0007] a contact structure comprising a first contact layer and a second contact layer, the first contact layer being in contact with the first conductive structure, and the bottom of the second contact layer being in contact with the top of the first contact layer; the width of the first contact layer being greater than the width of the bottom of the second contact layer;

[0008] wherein the lower surface of the contact structure is not lower than the lower surface of the electrode cover layer, the resistivity of the first conductive structure is not greater than the resistivity of the contact structure, and not greater than the resistivity of the electrode cover layer.

[0009] In one embodiment, the first contact layer is located on the upper surface of the first conductive structure, and the thermal expansion coefficient of the first contact layer is not greater than the thermal expansion coefficient of the first conductive structure.

[0010] In one embodiment, the semiconductor structure further comprises an insulating layer located on the upper surface of the first conductive structure.

[0011] The first contact layer comprises a first conductive layer and a first barrier layer, the first conductive layer is located in the insulating layer, and the first barrier layer is located between the first conductive layer and the insulating layer and between the first conductive layer and the first conductive structure.

[0012] The second contact layer includes a second conductive layer and a second barrier layer, the second conductive layer is located in the insulating layer, and the second barrier layer is located between the second conductive layer and the insulating layer and between the second conductive layer and the first conductive layer.

[0013] In one of the embodiments, the first contact layer is located at the lower surface of the first conductive structure; and the semiconductor structure further includes an insulating layer, the insulating layer is located at the upper surface of the first conductive structure.

[0014] The first contact layer includes a first conductive layer and a first barrier layer, the first conductive layer is located in the electrode cover layer, and the first barrier layer is located between the first conductive layer and the electrode cover layer.

[0015] The second contact layer includes a second conductive layer and a second barrier layer, the second conductive layer includes a portion located in the insulating layer and a portion located in the first conductive structure, and the second barrier layer is located between the second conductive layer and the insulating layer, between the second conductive layer and the first conductive structure, and between the second conductive layer and the first conductive layer.

[0016] In one of the embodiments, the electrode cover layer includes:

[0017] The electrode cover structure is located on the substrate.

[0018] The adhesion structure is located at the upper surface of the electrode cover structure.

[0019] In one of the embodiments, the lower surface of the first contact layer is higher than the lower surface of the adhesion structure, the first conductive layer is located in the adhesion structure, and the first barrier layer is located between the first conductive layer and the adhesion structure.

[0020] The adhesion structure has a doping concentration not less than a doping concentration of the electrode cover structure, and the first conductive structure has a doping concentration not greater than the doping concentration of the adhesion structure.

[0021] In one of the embodiments, the lower surface of the first contact layer is flush with the lower surface of the adhesion structure, the first conductive layer is located in the adhesion structure, and the first barrier layer is located between the first conductive layer and the adhesion structure and between the first conductive layer and the electrode cover structure.

[0022] In one of the embodiments, the lower surface of the first contact layer is lower than the lower surface of the adhesion structure, the first conductive layer includes a portion located in the adhesion structure and a portion located in the electrode cover structure, and the first barrier layer is located between the first conductive layer and the adhesion structure and between the first conductive layer and the electrode cover structure.

[0023] In one of the embodiments, the semiconductor structure further includes:

[0024] The metal wiring layer is located on the contact structure and in contact with the top of the contact structure.

[0025] The first conductive structure, the first conductive layer and the second conductive layer are first material layers, and the first material layers at least include one of a tungsten material layer, a tungsten-silicon material layer, a tungsten nitride material layer and a tungsten-silicon nitride material layer.

[0026] A method for manufacturing a semiconductor structure, comprising:

[0027] forming an electrode covering layer on a substrate;

[0028] forming a first conductive structure on an upper surface of the electrode covering layer;

[0029] forming an insulating layer on the first conductive structure and forming a contact structure in the insulating layer;

[0030] The contact structure includes a first contact layer and a second contact layer, the first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer; the lower surface of the contact structure is not lower than the lower surface of the electrode covering layer, the resistivity of the first conductive structure is not greater than the resistivity of the contact structure, and is not greater than the resistivity of the electrode covering layer.

[0031] In one embodiment, the insulating layer includes a first insulating layer and a second insulating layer, and the step of forming the insulating layer on the first conductive structure and forming the contact structure in the insulating layer includes:

[0032] forming the first insulating layer on an upper surface of the first conductive structure;

[0033] forming a first contact hole in the first insulating layer;

[0034] forming the first contact layer in the first contact hole;

[0035] forming the second insulating layer on an upper surface of the first insulating layer and an upper surface of the first contact layer;

[0036] forming a second contact hole in the second insulating layer, the second contact hole exposing the first contact layer, and the width of the bottom of the second contact hole is less than the width of the first contact layer;

[0037] forming the second contact layer in the second contact hole.

[0038] In one embodiment, the method for manufacturing a semiconductor structure further includes:

[0039] forming a metal wiring layer on the insulating layer, the metal wiring layer being in contact with the top of the contact structure;

[0040] The first conductive structure, the first contact layer and the second contact layer are first material layers, and the first material layers at least include one of a tungsten material layer, a tungsten silicon material layer, a tungsten nitride material layer and a tungsten silicon nitride material layer; the first contact layer has a thermal expansion coefficient not greater than a thermal expansion coefficient of the first conductive structure.

[0041] A method for manufacturing a semiconductor structure, comprising:

[0042] forming an electrode covering layer on a substrate;

[0043] forming a first contact layer in the electrode covering layer;

[0044] forming a first conductive structure on an upper surface of the electrode covering layer and an upper surface of the first contact layer;

[0045] forming an insulating layer on the first conductive structure;

[0046] forming a second contact layer in the insulating layer and the first conductive structure, a bottom of the second contact layer being in contact with a top of the first contact layer;

[0047] The contact structure includes the first contact layer and the second contact layer, a width of the first contact layer is greater than a width of a bottom of the second contact layer; a lower surface of the contact structure is not lower than a lower surface of the electrode covering layer, a resistivity of the first conductive structure is not greater than a resistivity of the contact structure, and not greater than a resistivity of the electrode covering layer.

[0048] In one of the embodiments, the electrode covering layer includes an electrode covering structure and an adhesion structure which are sequentially stacked from the substrate, and the step of forming the electrode covering layer on the substrate includes:

[0049] forming the electrode covering structure on the substrate;

[0050] forming the adhesion structure on an upper surface of the electrode covering structure.

[0051] In one of the embodiments, the step of forming the first contact layer in the electrode covering layer includes:

[0052] forming a first contact hole in the adhesion structure, a bottom of the first contact hole being higher than a lower surface of the adhesion structure;

[0053] forming the first contact layer in the first contact hole;

[0054] The adhesion structure has a doping concentration not less than a doping concentration of the electrode covering structure, and the first conductive structure has a doping concentration not greater than the doping concentration of the adhesion structure.

[0055] In one of the embodiments, the step of forming the first contact layer in the electrode covering layer includes:

[0056] forming a first contact hole in the adhesive structure, the first contact hole exposing an upper surface of the electrode covering structure;

[0057] forming a first contact layer in the first contact hole.

[0058] In one of the embodiments, the step of forming the first contact layer in the electrode covering layer comprises:

[0059] forming a first contact hole in the adhesive structure and the electrode covering structure, the first contact hole penetrating through the adhesive structure and extending into the electrode covering layer;

[0060] forming a first contact layer in the first contact hole.

[0061] In one of the embodiments, the method for preparing the semiconductor structure further comprises:

[0062] forming a metal wiring layer on the insulating layer, the metal wiring layer being in contact with the top of the contact structure;

[0063] The first conductive structure, the first contact layer and the second contact layer are all first material layers, and the first material layer at least comprises one of a tungsten material layer, a tungsten silicon material layer, a tungsten nitride material layer and a tungsten silicon nitride material layer; the thermal expansion coefficient of the first contact layer is not greater than the thermal expansion coefficient of the first conductive structure.

[0064] The semiconductor structure comprises an electrode covering layer on a substrate, a first conductive structure on an upper surface of the electrode covering layer, a contact structure comprising a first contact layer and a second contact layer, the first contact layer being in contact with the first conductive structure, and the bottom of the second contact layer being in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer, the lower surface of the contact structure is not lower than the lower surface of the electrode covering layer, the resistivity of the first conductive structure is not greater than the resistivity of the contact structure and is not greater than the resistivity of the electrode covering layer. Compared with directly forming a contact structure in contact with the electrode covering layer, the contact area between the contact structure and the electrode covering layer is increased, and the formation of a cavity in the contact structure is avoided, thereby reducing the contact resistance. Meanwhile, the contact structure is in contact with the electrode covering layer through the first conductive structure whose resistivity is not greater than the resistivity of the contact structure and is not greater than the resistivity of the electrode covering layer, thereby reducing the bulk resistance between the contact structure and the capacitor structure below the electrode covering layer. Furthermore, the first contact layer in contact with the first conductive structure plays a supporting role in the chemical mechanical polishing process, thereby avoiding the problem of load effect or depression of the contact structure.

[0065] The method for manufacturing the semiconductor structure comprises forming an electrode cover layer on a substrate; forming a first conductive structure on the upper surface of the electrode cover layer; forming an insulating layer on the first conductive structure, and forming a contact structure in the insulating layer; wherein the contact structure comprises a first contact layer and a second contact layer, the first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer; the lower surface of the contact structure is not lower than the lower surface of the electrode cover layer, the resistivity of the first conductive structure is not greater than the resistivity of the contact structure, and is not greater than the resistivity of the electrode cover layer. Compared with directly forming a contact structure in contact with the electrode cover layer, the contact area of the contact structure and the electrode cover layer is increased, and at the same time, the problem of forming a cavity in the contact structure is avoided, and the contact resistance is reduced. At the same time, the contact structure is in contact with the electrode cover layer through the first conductive structure whose resistivity is not greater than the resistivity of the contact structure, and is not greater than the resistivity of the electrode cover layer, so that the bulk resistance between the contact structure and the capacitor structure below the electrode cover layer is reduced. Moreover, the first contact layer in contact with the first conductive structure plays a supporting role in the chemical mechanical polishing process, and the problems of load effect or depression of the contact structure are avoided.

[0066] The method for manufacturing the semiconductor structure comprises forming a first contact layer in the electrode cover layer; forming a first conductive structure on the upper surface of the electrode cover layer and the upper surface of the first contact layer; forming an insulating layer on the first conductive structure; forming a second contact layer in the insulating layer and the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; wherein the contact structure comprises a first contact layer and a second contact layer, the first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer; the lower surface of the contact structure is not lower than the lower surface of the electrode cover layer, the resistivity of the first conductive structure is not greater than the resistivity of the contact structure, and is not greater than the resistivity of the electrode cover layer. The contact area of the contact structure and the electrode cover layer is increased, and the etching process for forming the second contact layer is provided with process redundancy, so that the etching process for forming the second contact layer does not etch to the electrode cover layer, and the bulk resistance between the contact structure and the capacitor structure below the electrode cover layer is reduced. Moreover, the first contact layer in contact with the first conductive structure plays a supporting role in the chemical mechanical polishing process, and the problems of load effect or depression of the contact structure are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0068] Figure 1 This is a schematic flowchart of the semiconductor structure fabrication method in the first embodiment;

[0069] Figure 2 This is a flowchart illustrating step S106 in one embodiment;

[0070] Figure 3 A schematic cross-sectional view of a semiconductor structure after the formation of the first contact hole in the method for fabricating the semiconductor structure provided in the first embodiment;

[0071] Figure 4 for Figure 3 A cross-sectional schematic diagram of a semiconductor structure after the formation of the second contact hole in a semiconductor structure fabrication method provided in a corresponding embodiment;

[0072] Figure 5 for Figure 4 A cross-sectional schematic diagram of a semiconductor structure after the formation of the second contact layer in a corresponding embodiment of the semiconductor structure fabrication method;

[0073] Figure 6 This is a schematic flowchart of the semiconductor structure fabrication method of the second embodiment;

[0074] Figure 7 A schematic cross-sectional view of a semiconductor structure after the formation of an insulating layer in the method for fabricating the semiconductor structure provided in the second embodiment;

[0075] Figure 8 for Figure 7 A cross-sectional schematic diagram of a semiconductor structure after the formation of the second contact layer in the semiconductor structure fabrication method provided in the corresponding embodiment;

[0076] Figure 9 This is a schematic diagram of the process of forming an electrode capping layer on a substrate according to an embodiment;

[0077] Figure 10 This is a schematic diagram of a process for forming a first contact layer within an electrode capping layer in a semiconductor structure fabrication method provided in one embodiment.

[0078] Figure 11 for Figure 10 A cross-sectional schematic diagram of a semiconductor structure after the formation of the second contact layer in a corresponding embodiment of the semiconductor structure fabrication method;

[0079] Figure 12 Another schematic diagram of a process for forming a first contact layer within an electrode capping layer in a method for fabricating a semiconductor structure according to another embodiment;

[0080] Figure 13 forFigure 12 FIG. 6 is a cross-sectional view of another semiconductor structure after forming a second contact layer in a method of fabricating a semiconductor structure according to an embodiment of the present application;

[0081] Figure 14 FIG. 7 is another flowchart of forming a first contact layer in an electrode covering layer in a method of fabricating a semiconductor structure according to another embodiment of the present application;

[0082] Figure 15 FIG. 8 is a cross-sectional view of another semiconductor structure after forming a second contact layer in a method of fabricating a semiconductor structure according to another embodiment of the present application; Figure 14

[0083] BRIEF DESCRIPTION OF DRAWINGS

[0084] 102, electrode covering layer; 104, first conductive structure; 106, insulating layer; 108, contact structure; 110, metal wiring layer; 202, first insulating layer; 204, second insulating layer; 206, first contact layer; 208, second contact layer; 210, electrode covering structure; 212, adhesion structure; 302, first contact hole; 304, second contact hole; 402, first barrier layer; 404, first conductive layer; 406, second barrier layer; 408, second conductive layer. DETAILED DESCRIPTION

[0085] In order to facilitate the understanding of the present application, a more complete understanding of the present application can be had by reference to the following description and the accompanying drawings. The preferred embodiments of the present application are described in the following description and illustrated in the accompanying drawings. However, various embodiments of the present application can be realized and achieved by different forms. The embodiments are selected to describe the best mode for the disclosure of the present application with the best mode.

[0086] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0087] ​It will be understood that when an element or layer is referred to as being "on" or "adjacent" another element or layer, it can be directly on the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "on surface", it is not present between intervening elements or layers. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application, for example, a first contact layer can be termed a second contact layer, and similarly, a first conductive layer can be termed a second conductive layer, without departing from the scope of the present application; both the first conductive layer and the second conductive layer are conductive layers, but they are not the same conductive layer.

[0088] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and / or

[0089] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. As used herein, the term "comprises" and / or "comprising", and the like are used synonymously with the term "includes" and / or "including" and / or "containing" and / or "containing", and are used to specify the presence of stated features, integers, steps, operations, elements, and / or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, the term "plurality" means at least two, for example, two, three or the like, unless otherwise specifically indicated. As used herein, the term "several" means at least one, for example, one, two or the like, unless otherwise specifically indicated.

[0090] Embodiments of the application are described herein with reference to the drawings, which show ideal embodiments (and intermediate structures) of the application. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments of the application should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle will, typically, have rounded or curved features and / or a gradient of implant concentration at its edges rather than a binary change between an implanted region and a non-implanted region. Similarly, a buried region formed by implantation can result in some implantation in a region between the buried region and a surface through which the implant was performed. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the application.

[0091] Figure 1 FIG. 1 is a flowchart illustrating a method for fabricating a semiconductor structure according to a first embodiment of the present application; Figure 1 In this embodiment, the method for fabricating a semiconductor structure comprises:

[0092] S102, forming an electrode covering layer on the substrate.

[0093] Specifically, the electrode covering layer is formed on the substrate, and covers the capacitor structure formed in the substrate. Exemplarily, the material of the electrode covering layer comprises at least one of boron-doped polysilicon material, boron-doped germanium-silicon material.

[0094] S104, forming a first conductive structure on the upper surface of the electrode covering layer.

[0095] Specifically, the first conductive structure is formed on the upper surface of the electrode covering layer using a deposition process well known to those skilled in the art. Exemplarily, the material of the first conductive structure comprises at least one of tungsten, tungsten nitride, tungsten silicide.

[0096] S106, forming an insulating layer on the first conductive structure, and forming a contact structure in the insulating layer.

[0097] In this embodiment, the insulating layer is formed on the upper surface of the first conductive structure, and the contact structure is formed in the insulating layer. Specifically, the contact structure comprises a first contact layer and a second contact layer, the first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer. Further, the lower surface of the contact structure is not lower than the lower surface of the electrode covering layer, the resistivity of the first conductive structure is not greater than the resistivity of the contact structure, and further, the resistivity of the first conductive structure is not greater than the resistivity of the electrode covering layer.

[0098] Compared with directly forming the contact structure in contact with the electrode cover layer, the contact area of the contact structure with the electrode cover layer is increased in the embodiment, and the contact resistance is reduced. At the same time, the formation of a cavity in the contact structure is avoided, the contact structure is in contact with the electrode cover layer through the first conductive structure whose resistivity is not greater than the resistivity of the contact structure and not greater than the resistivity of the electrode cover layer, the thickness of the contact structure (the distance between the lower surface and the upper surface of the contact structure) is reduced, and the body resistance between the contact structure and the capacitor structure below the electrode cover layer is reduced. Moreover, the first contact layer in contact with the first conductive structure plays a supporting role in the chemical mechanical polishing process, avoiding the problem of load effect or depression of the contact structure.

[0099] Figure 2 For a flowchart of step S106 in an embodiment, see Figure 2 In the embodiment, the insulating layer includes a first insulating layer and a second insulating layer, and step S106 includes:

[0100] S202, forming a first insulating layer on the upper surface of the first conductive structure;

[0101] S204, forming a first contact hole in the first insulating layer;

[0102] S206, forming the first contact layer in the first contact hole;

[0103] S208, forming a second insulating layer on the upper surface of the first insulating layer and the upper surface of the first contact layer;

[0104] S210, forming a second contact hole in the second insulating layer to expose the first contact layer;

[0105] S212, forming a second contact layer in the second contact hole.

[0106] Specifically, Figure 3 A cross-sectional schematic diagram of a semiconductor structure after forming the first contact hole 302 in the preparation method of the semiconductor structure provided in the first embodiment, Figure 4 For Figure 3 A cross-sectional schematic diagram of a semiconductor structure after forming the second contact hole 304 in the preparation method of the semiconductor structure provided in the corresponding embodiment; see Figure 3 、 Figure 4First, a first insulating layer 202 is formed on the upper surface of the first conductive structure 104 using deposition processes well known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, and atomic layer deposition. Further, the material of the first insulating layer 202 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride. Second, the first insulating layer 202 is patterned using photolithography to form a first contact hole 302 penetrating the first insulating layer 202. The bottom of the first contact hole 302 exposes the first conductive structure 104, and the depth D1 of the first contact hole 302 is not greater than the distance between the upper surface of the first insulating layer 202 and the second conductive structure. The distance T1 between the lower surfaces of the first conductive structure 104 is exemplarily such that the bottom of the first contact hole 302 exposes the upper surface of the first conductive structure 104. Further, the first contact hole 302 is formed using a dry etching process and / or a wet etching process. Next, a first contact layer 206 is formed by filling the first contact hole 302. Further, after forming a first contact material layer in the first contact hole 302 with an upper surface higher than the upper surface of the first insulating layer 202, the excess first contact material layer is removed by a chemical polishing process to obtain a first contact layer 206 composed of the remaining first contact material layer. The upper surface of the first contact layer 206 is flush with the upper surface of the first insulating layer 202.

[0107] Furthermore, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the first conductive structure 104. During the operation of the semiconductor structure, the device temperature will rise. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the first conductive structure 104, the abnormality of cracks appearing and extending in the first conductive structure 104 due to the mismatch of thermal expansion coefficients is avoided.

[0108] Figure 5 for Figure 4 One of the cross-sectional schematic diagrams of a semiconductor structure after the formation of the second contact layer 208 in the semiconductor structure fabrication method provided in one corresponding embodiment is shown below. Figure 4 , Figure 5First, a second insulating layer 204 is formed on the upper surface of the first insulating layer 202. The second insulating layer 204 simultaneously covers the upper surface of the first contact layer 206, wherein the first insulating layer 202 and the second insulating layer 204 together constitute the insulating layer 106. Further, the material of the second insulating layer 204 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride; even further, the materials of the second insulating layer 204 and the first insulating layer 202 are the same, for example, both are silicon oxide. Next, a second contact hole 304 exposing the first contact layer 206 is formed in the second insulating layer 204 by photolithography etching. The width W1 of the bottom of the second contact hole 304 along the X-axis is smaller than the width W2 of the first contact layer 206 along the X-axis (where the X-axis is perpendicular to the contact structure extension direction, and the Y-axis is parallel to the line connecting the first and second parts). At this time, the cross-sectional schematic diagram of the semiconductor structure is as follows. Figure 4 As shown; further, the second contact hole 304 exposes the upper surface of the first contact layer 206, and can be formed using a dry etching process and / or a wet etching process. Next, a second contact layer 208 is formed within the second contact hole 304. In this case, the second contact layer 208 can be formed using the same method as the first contact layer 206, which will not be described again. Further, the upper surface of the second contact layer 208 is flush with the upper surface of the second insulating layer 204. At this point, the cross-sectional view of the semiconductor structure is as shown. Figure 4 As shown.

[0109] Continue to refer to Figure 5 Furthermore, the first contact layer 206 includes a first barrier layer 402 and a first conductive layer 404. The step of filling the first contact hole 302 to form the first contact layer 206 includes: forming the first barrier layer 402 in the first contact hole 302, the first barrier layer 402 covering the sidewalls and bottom of the first contact hole 302. In practical applications, the first barrier layer 402 can be made of different materials according to process requirements, such as a titanium nitride barrier layer, a titanium barrier layer, etc.; then, forming the first conductive layer 404 on the surface of the first barrier layer 402 that is away from the first insulating layer 202 and away from the first conductive structure 104, the first conductive layer 404 filling the first contact hole 302. In practical applications, the first barrier layer 402 can be made of different materials according to process requirements, such as a tungsten conductive layer, a copper conductive layer, an aluminum conductive layer, etc. By setting the first barrier layer 402, the diffusion of conductive particles in the first conductive layer 404 can be blocked.

[0110] Continue to refer to Figure 5Furthermore, the second contact layer 208 includes a second barrier layer 406 and a second conductive layer 408. The step of filling the second contact hole 304 to form the second contact layer 208 includes: forming a second barrier layer 406 in the second contact hole 304, the second barrier layer 406 covering the sidewalls and bottom of the second contact hole 304. In practical applications, the second barrier layer 406 can be made of different materials according to process requirements, such as a titanium nitride barrier layer, a titanium barrier layer, etc.; then, forming a second conductive layer 408 on the surface of the second barrier layer 406 that is away from the second insulating layer 204 and away from the first contact layer 206, the second conductive layer 408 filling the second contact hole 304. In practical applications, the second barrier layer 406 can be made of different materials according to process requirements, such as a tungsten conductive layer, a copper conductive layer, an aluminum conductive layer, etc. By setting the second barrier layer 406, the diffusion of conductive particles in the first conductive layer 404 can be blocked. Furthermore, the second barrier layer 406 is made of the same material as the first barrier layer 402, and / or the second conductive layer 408 is made of the same material as the first conductive layer.

[0111] In one embodiment, the first conductive structure 104, the first contact layer 206, and the second contact layer 208 are all first material layers, and the first material layer includes at least one of tungsten material layer, tungsten silicon material layer, tungsten nitride material layer, and tungsten silicon nitride material layer.

[0112] Continue to refer to Figure 5 In one embodiment, the method for fabricating the semiconductor structure further includes:

[0113] A metal interconnect layer 110 is formed on the insulating layer 106. The metal interconnect layer 110 is in contact with the top of the contact structure 108, that is, the metal interconnect layer 110 is in contact with the top of the second contact layer 208. The capacitor array under the electrode cover layer 102 can be led out to the surface of the device through the metal interconnect layer 110, so that the capacitor array can be connected to the required location.

[0114] Furthermore, the metal interconnect layer 110 includes a metal ion blocking layer and a metal connecting layer. The step of forming the metal interconnect layer 110 on the insulating layer 106 includes: forming a metal ion blocking layer on the upper surface of the insulating layer 106, thereby preventing metal ions in the metal interconnect layer 110 from diffusing into the insulating layer 106; forming a metal connecting layer on the upper surface of the metal ion blocking layer and the second contact layer 208, wherein the metal connecting layer is in contact with the top surface of the second contact layer 208.

[0115] Figure 6 This is a schematic flowchart of the semiconductor structure fabrication method of the second embodiment, referencing... Figure 6 In this embodiment, the method for fabricating the semiconductor structure includes:

[0116] S302, forming an electrode capping layer 102 on the substrate.

[0117] S304, a first contact layer 206 is formed within the electrode cover layer 102.

[0118] Specifically, a first contact layer 206 with a lower surface not lower than the lower surface of the electrode cover layer 102 is formed within the electrode cover layer 102 using a preparation process well known to those skilled in the art.

[0119] S306, a first conductive structure 104 is formed on the upper surface of the electrode cover layer 102 and the upper surface of the first contact layer 206.

[0120] S308, an insulating layer 106 is formed on the first conductive structure 104.

[0121] S310, a second contact layer 208 is formed in the insulating layer 106 and the first conductive structure 104, the bottom of which is in contact with the top of the first contact layer 206.

[0122] The contact structure 108 includes a first contact layer 206 and a second contact layer 208. The width of the first contact layer 206 is greater than the width of the bottom of the second contact layer 208. The lower surface of the contact structure 108 is not lower than the lower surface of the electrode cover layer 102. The resistivity of the first conductive structure 104 is not greater than the resistivity of the contact structure 108 and not greater than the resistivity of the electrode cover layer 102.

[0123] The method for fabricating a semiconductor structure according to the present invention includes forming a first contact layer 206 within an electrode capping layer 102; forming a first conductive structure 104 on the upper surface of the electrode capping layer 102 and the upper surface of the first contact layer 206; forming an insulating layer 106 on the first conductive structure 104; and forming a second contact layer 208 in the insulating layer 106 and the first conductive structure 104, wherein the bottom of the second contact layer 208 is in contact with the top of the first contact layer 206; wherein the contact structure 108 includes a first contact layer 206 and a second contact layer 208, the first contact layer 206 is in contact with the first conductive structure 104, and the bottom of the second contact layer 208 is in contact with the top of the first contact layer 206; the width of the first contact layer 206 is greater than the width of the bottom of the second contact layer 208; the lower surface of the contact structure 108 is not lower than the lower surface of the electrode capping layer 102; and the resistivity of the first conductive structure 104 is not greater than the resistivity of the contact structure 108 and not greater than the resistivity of the electrode capping layer 102. Compared to the first embodiment, the contact area between the contact structure 108 and the electrode capping layer 102 is increased, and process redundancy is provided for the etching process forming the second contact layer 208, preventing the etching process forming the second contact layer 208 from etching into the electrode capping layer 102, and reducing the bulk resistance between the contact structure 108 and the capacitor structure below the electrode capping layer 102. Furthermore, the first contact layer 206, which is in contact with the first conductive structure 104, plays a supporting role during chemical mechanical polishing, avoiding the problems of load effect or contact structure 108 depression.

[0124] Figure 7 A schematic cross-sectional view of a semiconductor structure after forming an insulating layer 106 in the method for fabricating the semiconductor structure provided in the second embodiment; Figure 8 for Figure 7 A cross-sectional schematic diagram of a semiconductor structure after the formation of the second contact layer 208 in a corresponding embodiment of the semiconductor structure fabrication method; see also Figure 7In this embodiment, the semiconductor structure fabrication method is as follows: First, a first contact hole 302 is formed in the electrode capping layer 102 using a photolithography etching process. The depth D2 of the first contact hole 302 is not greater than the thickness T2 of the electrode capping layer 102. Then, a first contact layer 206 is formed by filling the first contact hole 302. Further, the first contact layer 206 is flush with the upper surface of the electrode capping layer 102. Further still, the first contact layer 206 includes a first barrier layer 402 covering the bottom and sidewalls of the first contact hole 302 and a first conductive layer 404 filling the first contact hole 302. The definitions of the first barrier layer 402 and the first conductive layer 404 are as described in the first embodiment and will not be repeated here. Second, a first conductive structure 104 is formed on the upper surface of the electrode capping layer 102 using a deposition process well known to those skilled in the art. The first conductive structure 104 extends along the upper surface of the electrode capping layer 102 and covers the upper surface of the first contact layer 206. Then, an insulating layer 106 is formed on the upper surface of the first conductive structure 104. The material of the insulating layer 106 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride. Thirdly, a second contact hole 304 is formed in the insulating layer 106 by photolithography etching. (See [link to documentation]). Figure 8 Furthermore, the second contact hole 304 penetrates the first conductive structure 104, exposing the upper surface of the first contact layer 206. At this point, the depth D3 of the second contact hole 304 is equal to the distance T3 between the upper surface of the insulating layer 106 and the lower surface of the first conductive structure 104. Then, a second contact layer 208 is formed in the second contact hole 304, with its bottom contacting the top of the first contact layer 206. Further, the second contact layer 208 includes a second barrier layer 406 covering the bottom and sidewalls of the second contact hole 304 and a second conductive layer 408 filling the second contact hole 304. The definitions of the second barrier layer 406 and the second conductive layer 408 are described in the first embodiment and will not be repeated here.

[0125] Compared to the first embodiment, the contact area between the contact structure 108 and the electrode cover layer 102 in the second embodiment is increased by the sidewall contact portion of the first contact layer 206 (e.g., Figure 8 The sum of the areas of the corresponding parts of S1 and S2 reduces the contact resistance between the contact structure 108 and the electrode cover layer 102, and increases the adhesion between the contact structure 108 and the electrode cover layer 102.

[0126] Furthermore, the first conductive structure 104 and the first contact layer 206 are made of the same material. In this case, the second contact hole 304 penetrates the insulating layer 106, exposing the first conductive structure 104. The depth D3 of the second contact hole 304 is greater than or equal to the thickness of the insulating layer 106 and less than or equal to the distance T3 between the upper surface of the insulating layer 106 and the lower surface of the first conductive structure 104. For example, the depth D3 of the second contact hole 304 is equal to the thickness of the insulating layer 106. The second contact layer 208 is connected to the top of the first contact layer 206 through the first conductive structure 104; that is, the first conductive structure 104 is equivalent to a part of the first contact layer 206, and can be considered as the second contact layer 208 contacting the top of the first contact layer 206. This increases the adhesion between the contact structure 108 and the first conductive structure 104, and between the first contact layer 206 and the second contact layer 208. It also reduces the etching depth of the second contact hole, avoiding the problem of voids in the contact structure 108 during subsequent filling.

[0127] In one embodiment, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the electrode capping layer 102. During the operation of the semiconductor structure, the device temperature rises. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the electrode capping layer 102, the abnormality of cracks appearing and extending in the electrode capping layer 102 due to a mismatch in the coefficients of thermal expansion is avoided.

[0128] Furthermore, the coefficient of thermal expansion of the second contact layer 208 is not greater than the coefficient of thermal expansion of the first conductive structure 104. During the operation of the semiconductor structure, the device temperature will rise. By setting the coefficient of thermal expansion of the second contact layer 208 to be no greater than the coefficient of thermal expansion of the first conductive structure 104, the abnormality of cracks appearing and extending in the first conductive structure 104 due to the mismatch of thermal expansion coefficients is avoided.

[0129] In one embodiment, the resistivity of the first conductive structure 104 is less than the resistivity of the electrode capping layer 102. For example, the doping concentration of the first conductive structure 104 is greater than the doping concentration of the electrode capping layer 102. This setting can reduce the resistivity of the contact resistance between the contact structure 108 and the electrode capping layer 102, thereby reducing the resistance value of the contact resistance.

[0130] In one embodiment, the resistivity of the first conductive structure 104 is less than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. This setting can also reduce the resistivity of the contact resistance between the contact structure 108 and the electrode cover layer 102, thereby reducing the resistance value of the contact resistance.

[0131] Figure 9 This is a schematic diagram of the process of forming an electrode capping layer 102 on a substrate according to an embodiment. See alsoFigure 9 In this embodiment, the electrode capping layer 102 includes: an electrode capping structure 210 and an adhesion structure 212 sequentially stacked from the substrate. The step of forming the electrode capping layer 102 on the substrate includes:

[0132] S402, forming an electrode covering structure 210 on the substrate;

[0133] S404, an adhesion structure 212 is formed on the upper surface of the electrode covering structure 210.

[0134] This embodiment increases the adhesion between the electrode covering structure 210 and the first conductive structure 104 by setting the adhesion structure 212.

[0135] In one embodiment, the material of the electrode covering structure 210 includes at least one of boron-doped polycrystalline silicon and boron-doped germanium-silicon. Further, the material of the electrode covering structure 210 is boron-doped germanium-silicon.

[0136] In one embodiment, the material of the adhesion structure 212 includes at least one of boron-doped silicon, boron-doped amorphous silicon, boron-doped polycrystalline silicon, tungsten nitride, tungsten silicide, and tungsten nitride silicon. Further, the material of the adhesion structure 212 is boron-doped polycrystalline silicon.

[0137] In one embodiment, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the adhesion structure 212. During the operation of the semiconductor structure, the device temperature rises. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the adhesion structure 212, the abnormality of cracks appearing and extending in the adhesion structure 212 due to a mismatch in the coefficients of thermal expansion is avoided.

[0138] Figure 10 This is a schematic flowchart illustrating the process of forming a first contact layer 206 within an electrode capping layer 102 in a semiconductor structure fabrication method provided in one embodiment. In this embodiment, the step of forming the first contact layer 206 within the electrode capping layer 102 includes:

[0139] S502, a first contact hole 302 is formed in the adhesion structure 212, and the bottom of the first contact hole 302 is higher than the lower surface of the adhesion structure 212.

[0140] S504, A first contact layer 206 is formed in the first contact hole 302;

[0141] Figure 11 for Figure 10A cross-sectional schematic diagram of a semiconductor structure after the formation of the second contact layer 208 is provided in a corresponding embodiment of the semiconductor structure fabrication method. Specifically, firstly, a first contact hole 302 is formed in the adhesion structure 212 using a photolithography etching process well known to those skilled in the art. The depth D4 of the first contact hole 302 is less than the thickness T4 of the adhesion structure 212. Secondly, a first contact layer 206 is formed within the first contact hole 302. For example, the upper surface of the first contact layer 206 is flush with the upper surface of the adhesion structure 212. For a description of the first contact layer 206 in this embodiment, please refer to [link to relevant documentation]. Figure 8 The corresponding embodiments are not described in detail here. Next, a first conductive structure 104 and an insulating layer 106 are sequentially formed on the electrode covering structure 210, and a second contact layer 208 is formed in the insulating layer 106 and the first conductive structure 104. The second contact layer 208 penetrates the insulating layer 106 and contacts the top of the first contact layer 206; for a description of the second contact layer 208 in this embodiment, please refer to [link to relevant documentation]. Figure 8 The corresponding embodiments will not be described in detail here. By setting the adhesion structure 212, the adhesion between the first conductive structure 104 and the electrode covering layer 102 is increased, while the contact area between the contact structure 108 and the electrode covering layer 102 is increased, thereby reducing the contact resistance.

[0142] In one embodiment, the resistivity of the first conductive structure 104 is not greater than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. In this case, the contact portion between the first conductive structure 104 and the adhesion structure 212 is equivalent to a part of the contact area between the contact structure 108 and the electrode cover layer 102, which further reduces the contact resistance.

[0143] Furthermore, the resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210. For example, the doping concentration of the adhesion structure 212 is not less than the doping concentration of the electrode covering structure 210. The resistivity of the first conductive structure 104 is not less than the resistivity of the adhesion structure 212. For example, the doping concentration of the first conductive structure 104 is not greater than the doping concentration of the adhesion structure 212. In this case, the contact area between the contact structure 108 and the electrode covering layer 102 is equivalent to the contact area between the adhesion structure 212 and the electrode covering structure 210, thereby reducing the contact resistance.

[0144] Furthermore, the resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210. For example, the doping concentration of the adhesion structure 212 is not less than the doping concentration of the electrode covering structure 210. The resistivity of the first conductive structure 104 is less than the resistivity of the adhesion structure 212. For example, the doping concentration of the first conductive structure 104 is greater than the doping concentration of the adhesion structure 212. In this case, the contact area between the contact structure 108 and the electrode covering layer 102 is equivalent to the contact area between the first conductive structure 104 and the adhesion structure 212 and the contact area between the contact structure 108 (first contact layer 206) and the electrode covering structure 210. While reducing the bulk resistance of the contact structure 108, the resistance value of the contact resistance is also reduced.

[0145] Figure 12 Another schematic diagram of the process for forming a first contact layer 206 within an electrode capping layer 102 in a semiconductor structure fabrication method provided in another embodiment. In this embodiment, the step of forming the first contact layer 206 within the electrode capping layer 102 includes:

[0146] S602, a first contact hole 302 is formed in the adhesion structure 212, the first contact hole 302 exposes the upper surface of the electrode covering structure 210;

[0147] S604, a first contact layer 206 is formed in the first contact hole 302.

[0148] Figure 13 for Figure 12 A cross-sectional schematic diagram of another semiconductor structure after the formation of the second contact layer 208 in the semiconductor structure fabrication method provided in one corresponding embodiment is shown. Specifically, firstly, a first contact hole 302 is formed in the adhesion structure 212 using a photolithography etching process well known to those skilled in the art. The depth D5 of the first contact hole 302 is equal to the thickness T5 of the adhesion structure 212, that is, the first contact hole 302 exposes the upper surface of the electrode cover structure 210. Secondly, a first contact layer 206 is formed in the first contact hole 302. For example, the upper surface of the first contact layer 206 is flush with the upper surface of the adhesion structure 212. The description of the first contact layer 206 in this embodiment is also referred to Figure 8 The corresponding embodiments are not described in detail here. Furthermore, a first conductive structure 104 and an insulating layer 106 are sequentially formed on the electrode covering structure 210, and a second contact layer 208 is formed in the insulating layer 106 and the first conductive structure 104. The second contact layer 208 penetrates the insulating layer 106 and contacts the top of the first contact layer 206; the description of the second contact layer 208 in this embodiment is also referred to... Figure 8The corresponding embodiments will not be described in detail here. By setting the adhesion structure 212, the adhesion between the first conductive structure 104 and the electrode covering layer 102 is increased, while the contact area between the contact structure 108 and the electrode covering layer 102 is increased, thereby reducing the contact resistance.

[0149] Furthermore, the resistivity of the first conductive structure 104 is not greater than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. The resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210. For example, the doping concentration of the adhesion structure 212 is not less than the doping concentration of the electrode covering structure 210. In this case, the contact portion between the first conductive structure 104 and the adhesion structure 212, the contact portion between the first contact layer 206 and the adhesion structure 212, and the contact portion between the first contact layer 206 and the electrode covering layer 102 together constitute the contact area between the contact structure 108 and the electrode covering layer 102, further reducing the contact resistance.

[0150] Furthermore, the resistivity of the first conductive structure 104 is less than that of the adhesive structure 212. For example, the doping concentration of the first conductive structure 104 is greater than that of the adhesive structure 212, which further reduces the bulk resistance of the contact structure 108.

[0151] Figure 14 This is another schematic diagram of the process for forming a first contact layer 206 within an electrode capping layer 102 in a method for fabricating a semiconductor structure according to another embodiment. In this embodiment, the step of forming the first contact layer 206 within the electrode capping layer 102 includes:

[0152] S702, a first contact hole 302 is formed in the adhesion structure 212 and the electrode covering structure 210, the first contact hole 302 penetrates the adhesion structure 212 and extends into the electrode covering layer 102.

[0153] S704, a first contact layer 206 is formed in the first contact hole 302.

[0154] Figure 15 for Figure 14A cross-sectional view of another semiconductor structure after the formation of the second contact layer 208 in the semiconductor structure fabrication method provided in one corresponding embodiment is shown. Specifically, firstly, a first contact hole 302 is formed in the adhesion structure 212 using a photolithography etching process well known to those skilled in the art. The first contact hole 302 penetrates the adhesion structure 212 and extends into the electrode cover structure 210. The depth D6 of the first contact hole 302 is greater than the thickness T5 of the adhesion structure 212 and less than the sum of the thickness T5 of the adhesion structure 212 and the thickness T6 of the electrode cover structure 210, that is, the bottom of the first contact hole 302 remains inside the electrode cover structure 210. Secondly, a first contact layer 206 is formed in the first contact hole 302. For example, the upper surface of the first contact layer 206 is flush with the upper surface of the adhesion structure 212. The description of the first contact layer 206 in this embodiment is also referred to Figure 8 The corresponding embodiments are not described in detail here. Furthermore, a first conductive structure 104 and an insulating layer 106 are sequentially formed on the electrode covering structure 210, and a second contact layer 208 is formed in the insulating layer 106 and the first conductive structure 104. The second contact layer 208 penetrates the insulating layer 106 and contacts the top of the first contact layer 206; the description of the second contact layer 208 in this embodiment is also referred to... Figure 8 The corresponding embodiments will not be described in detail here. By setting the adhesion structure 212, the adhesion between the first conductive structure 104 and the electrode covering layer 102 is increased, while the contact area between the contact structure 108 and the electrode covering layer 102 is increased, thereby reducing the contact resistance.

[0155] Furthermore, the resistivity of the first conductive structure 104 is not greater than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. In this case, the contact portion between the first conductive structure 104 and the adhesion structure 212, the contact portion between the first contact layer 206 and the adhesion structure 212, and the contact portion between the first contact layer 206 and the electrode cover layer 102 together constitute the contact area between the contact structure 108 and the electrode cover layer 102, which further increases the contact area, reduces the contact resistance, and at the same time reduces the bulk resistance of the contact structure 108. Furthermore, the resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210, and the resistivity of the adhesion structure 212 is less than the resistivity of the first conductive structure 104. At this time, the contact portion between the adhesion structure 212 and the electrode covering structure 210, and the contact portion between the first contact layer 206 and the electrode covering layer 102 together constitute the contact area between the contact structure 108 and the electrode covering layer 102, which further increases the contact area, reduces the contact resistance value and the volume resistance of the contact structure 108.

[0156] In one embodiment, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the first conductive structure 104. During the operation of the semiconductor structure, the temperature of the device will rise. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the first conductive structure 104, the abnormality of cracks appearing and extending at the contact surface between the first contact layer 206 and the first conductive structure 104 caused by the mismatch of thermal expansion coefficients is avoided.

[0157] Furthermore, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the adhesive structure 212, and the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the electrode cover layer 102. This setting avoids the abnormality of cracks and extensions between the first contact layer 206 and the adhesive structure 212 and / or between the first contact layer 206 and the electrode cover layer 102 caused by the mismatch of thermal expansion coefficients.

[0158] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 At least some of the steps may include multiple steps or stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the steps or stages in other steps. It is understood that in the above embodiments, the first contact hole 302 refers to the opening filled by the first contact layer 206, and the second contact hole 304 refers to the opening filled by the second contact layer 208. The positions of the first contact hole 302 and the second contact hole 304 in the cross-sectional view of the corresponding semiconductor structure in each embodiment may be the same or different.

[0159] See Figure 5This application also provides a semiconductor structure, including: an electrode capping layer 102, a first conductive structure 104, and a contact structure 108. The electrode capping layer 102 is located on a substrate (not shown in the figure). Exemplarily, the material of the electrode capping layer 102 includes at least one of boron-doped polycrystalline silicon and boron-doped germanium-silicon. The first conductive structure 104 is located on the upper surface of the electrode capping layer 102. Exemplarily, the first conductive structure 104 includes at least one of a tungsten conductive structure, a tungsten nitride conductive structure, a tungsten silicide conductive structure, and a tungsten nitride-silicon conductive structure. The contact structure 108 includes a first contact layer 206 and a second contact layer 208. 06 is in contact with the first conductive structure 104, and the bottom of the second contact layer 208 is in contact with the top of the first contact layer 206; the width W2 (length along the X-axis) of the first contact layer 206 is greater than the width W1 (length along the X-axis) of the bottom of the second contact layer 208; wherein, the lower surface of the contact structure 108 is not lower than the lower surface of the electrode cover layer 102, and the resistivity of the first conductive structure 104 is not greater than the resistivity of the contact structure 108 and not greater than the resistivity of the electrode cover layer 102.

[0160] The semiconductor structure of the present invention includes an electrode capping layer 102 located on a substrate, a first conductive structure 104 located on the upper surface of the electrode capping layer 102, and a contact structure 108 including a first contact layer 206 and a second contact layer 208. The first contact layer 206 is in contact with the first conductive structure 104, and the bottom of the second contact layer 208 is in contact with the top of the first contact layer 206. The width of the first contact layer 206 is greater than the width of the bottom of the second contact layer 208. The lower surface of the contact structure 108 is not lower than the lower surface of the electrode capping layer 102. The resistivity of the first conductive structure 104 is not greater than the resistivity of the contact structure 108 and not greater than the resistivity of the electrode capping layer 102. Compared with directly forming a contact structure 108 in contact with the electrode capping layer 102, this increases the contact area between the contact structure 108 and the electrode capping layer 102, while avoiding the formation of voids in the contact structure 108 and reducing the contact resistance. Meanwhile, the contact structure 108 contacts the electrode cover layer 102 via a first conductive structure 104 whose resistivity is no greater than that of the contact structure 108 and no greater than that of the electrode cover layer 102. This reduces the volume resistance between the contact structure 108 and the capacitor structure below the electrode cover layer 102, as well as the thickness of the contact structure 108 (the distance between the lower and upper surfaces of the contact structure). Furthermore, the first contact layer in contact with the first conductive structure provides support during chemical mechanical polishing, preventing problems such as load effects or contact structure depressions.

[0161] See also Figure 5In one embodiment, the first contact layer 206 is located on the upper surface of the first conductive structure 104, and the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the first conductive structure 104. During the operation of the semiconductor structure, the device temperature will rise. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the first conductive structure 104, the abnormality of cracks appearing and extending in the first conductive structure 104 due to a mismatch in the coefficients of thermal expansion is avoided.

[0162] See also Figure 5 In one embodiment, the semiconductor structure further includes an insulating layer 106106, located on the upper surface of the first conductive structure 104. The insulating layer 106 is made of at least one of silicon oxide, silicon nitride, and silicon oxynitride. The first contact layer 206 includes a first conductive layer 404 and a first barrier layer 402. The first conductive layer 404 is located within the insulating layer 106, and the first barrier layer 402 is located between the first conductive layer 404 and the insulating layer 106, and between the first conductive layer 404 and the first conductive structure 104. In practical applications, different materials for the first barrier layer 402 and the first conductive layer 404 can be selected according to process requirements. For example, the first barrier layer 402 can be a titanium nitride barrier layer, a titanium barrier layer, etc., and the first conductive layer 404 can be a tungsten conductive layer, a copper conductive layer, an aluminum conductive layer, etc. By setting the first barrier layer 402, the diffusion of conductive particles in the first conductive layer 404 can be blocked. Furthermore, the second contact layer 208 includes a second conductive layer 408 and a second barrier layer 406. The second conductive layer 408 is located within the insulating layer 106, and the second barrier layer 406 is located between the second conductive layer 408 and the insulating layer 106, and between the second conductive layer 408 and the first conductive layer 404. In practical applications, different materials can be selected for the second barrier layer 406 and the second conductive layer 408 according to process requirements. For example, the second barrier layer 406 can be a titanium nitride barrier layer, a titanium barrier layer, etc., and the second conductive layer 408 can be a tungsten conductive layer, a copper conductive layer, an aluminum conductive layer, etc. By setting the second barrier layer 406, the diffusion of conductive particles in the second conductive layer 408 can be blocked. Furthermore, the second barrier layer 406 and the first barrier layer 402 are made of the same material, and / or the second conductive layer 408 and the first conductive layer are made of the same material.

[0163] In one embodiment, the upper surface of the second contact layer 208 is flush with the upper surface of the second insulating layer 204.

[0164] See also Figure 5Furthermore, the insulating layer 106 includes a first insulating layer 202 located on the upper surface of the first conductive structure 104 and a second insulating layer 204 located on the upper surface of the first insulating layer 202. The first contact layer 206 is located in the first insulating layer 202. Furthermore, the upper surface of the first contact layer 206 is flush with the upper surface of the first insulating layer 202. The second contact layer 208 is located in the second insulating layer 204. Furthermore, the upper surface of the second contact layer 208 is flush with the upper surface of the second insulating layer 204.

[0165] In one embodiment, the material of the first insulating layer 202 and / or the second insulating layer 204 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride. Furthermore, the second insulating layer 204 and the first insulating layer 202 are made of the same material, for example, both of which are silicon oxide.

[0166] See also Figure 5 In one embodiment, the semiconductor structure further includes a metal interconnect layer 110, which is located on the contact structure 108 and in contact with the top of the contact structure 108. The metal interconnect layer 110 can lead the capacitor array below the electrode cover layer 102 to the surface of the device, making it easy to connect the capacitor array to the required location.

[0167] Furthermore, the metal interconnect layer 110 includes a metal ion blocking layer and a metal connecting layer. The metal ion blocking layer is located on the upper surface of the insulating layer 106. By setting the metal ion blocking layer, the purpose of preventing metal ions in the metal interconnect layer 110 from diffusing into the insulating layer 106 is achieved. The metal connecting layer is located on the upper surface of the metal ion blocking layer and the second contact layer 208, and the metal connecting layer is in contact with the top surface of the second contact layer 208.

[0168] See Figure 7 In one embodiment, the first contact layer 206 is located on the lower surface of the first conductive structure 104; the semiconductor structure also includes an insulating layer 106 located on the upper surface of the first conductive structure 104.

[0169] The first contact layer 206 includes a first conductive layer 404 and a first barrier layer 402. The first conductive layer 404 is located inside the electrode cover layer 102, and the first barrier layer 402 is located between the first conductive layer 404 and the electrode cover layer 102.

[0170] The second contact layer 208 includes a second conductive layer 408 and a second barrier layer 406. The second conductive layer 408 includes a portion located within the insulating layer 106 and a portion located within the first conductive structure 104. The second barrier layer 406 is located between the second conductive layer 408 and the insulating layer 106, between the second conductive layer 408 and the first conductive structure 104, and between the second conductive layer 408 and the first conductive structure 104. Figure 4 Compared with the corresponding embodiment, the contact area between the contact structure 108 and the electrode cover layer 102 is increased, and process redundancy is provided for the etching process of forming the second contact layer 208, so as to avoid the etching process of forming the second contact layer 208 from etching the electrode cover layer 102, and to reduce the bulk resistance between the contact structure 108 and the capacitor structure below the electrode cover layer 102.

[0171] Compared to the first embodiment, the contact area between the contact structure 108 and the electrode cover layer 102 in the second embodiment is increased by the sidewall contact portion of the first contact layer 206 (e.g., Figure 8 The sum of the areas of the corresponding parts of S1 and S2 reduces the contact resistance between the contact structure 108 and the electrode cover layer 102, and increases the adhesion between the contact structure 108 and the electrode cover layer 102.

[0172] Furthermore, the first conductive structure 104 and the first contact layer 206 are made of the same material. In this case, the second contact hole 304 penetrates the insulating layer 106, exposing the first conductive structure 104. The depth D3 of the second contact hole 304 is greater than or equal to the thickness of the insulating layer 106 and less than or equal to the distance T3 between the upper surface of the insulating layer 106 and the lower surface of the first conductive structure 104. For example, the depth D3 of the second contact hole 304 is equal to the thickness of the insulating layer 106. The second contact layer 208 is connected to the top of the first contact layer 206 through the first conductive structure 104; that is, the first conductive structure 104 is equivalent to a part of the first contact layer 206, and can be considered as the second contact layer 208 contacting the top of the first contact layer 206. This increases the adhesion between the contact structure 108 and the first conductive structure 104, and between the first contact layer 206 and the second contact layer 208. It also reduces the etching depth of the second contact hole, avoiding the problem of voids in the contact structure 108 during subsequent filling.

[0173] In one embodiment, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the electrode capping layer 102. During the operation of the semiconductor structure, the device temperature rises. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the electrode capping layer 102, the abnormality of cracks appearing and extending in the electrode capping layer 102 due to a mismatch in the coefficients of thermal expansion is avoided.

[0174] Furthermore, the coefficient of thermal expansion of the second contact layer 208 is not greater than the coefficient of thermal expansion of the first conductive structure 104. During the operation of the semiconductor structure, the device temperature will rise. By setting the coefficient of thermal expansion of the second contact layer 208 to be no greater than the coefficient of thermal expansion of the first conductive structure 104, the abnormality of cracks appearing and extending in the first conductive structure 104 due to the mismatch of thermal expansion coefficients is avoided.

[0175] In one embodiment, the resistivity of the first conductive structure 104 is less than the resistivity of the electrode capping layer 102. For example, the doping concentration of the first conductive structure 104 is greater than the doping concentration of the electrode capping layer 102. This setting can reduce the resistivity of the contact resistance between the contact structure 108 and the electrode capping layer 102, thereby reducing the resistance value of the contact resistance.

[0176] In one embodiment, the resistivity of the first conductive structure 104 is less than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. This setting can also reduce the resistivity of the contact resistance between the contact structure 108 and the electrode cover layer 102, thereby reducing the resistance value of the contact resistance.

[0177] See Figure 11 , Figure 13 , Figure 15 In one embodiment, the electrode capping layer 102 includes an electrode capping structure 210 and an adhesion structure 212, wherein the electrode capping structure 210 is located on a substrate, and the adhesion structure 212 is located on the upper surface of the electrode capping structure 210. This embodiment increases the adhesion between the electrode capping structure 210 and the first conductive structure 104 by providing the adhesion structure 212.

[0178] In one embodiment, the material of the electrode covering structure 210 includes at least one of boron-doped polycrystalline silicon and boron-doped germanium-silicon. Further, the material of the electrode covering structure 210 is boron-doped germanium-silicon.

[0179] In one embodiment, the material of the adhesion structure 212 includes at least one of boron-doped silicon, boron-doped amorphous silicon, boron-doped polycrystalline silicon, tungsten nitride, tungsten silicide, and tungsten nitride silicon. Further, the material of the adhesion structure 212 is boron-doped polycrystalline silicon.

[0180] In one embodiment, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the adhesion structure 212. During the operation of the semiconductor structure, the device temperature rises. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the adhesion structure 212, the abnormality of cracks appearing and extending in the adhesion structure 212 due to a mismatch in the coefficients of thermal expansion is avoided.

[0181] See Figure 11 In one embodiment, the lower surface of the first contact layer 206 is higher than the lower surface of the adhesion structure 212, the first conductive layer 404 is located inside the adhesion structure 212, and the first barrier layer 402 is located between the first conductive layer 404 and the adhesion structure 212. By setting the adhesion structure 212, the adhesion between the first conductive structure 104 and the electrode cover layer 102 is increased, while the contact area between the contact structure 108 and the electrode cover layer 102 is increased, and the contact resistance is reduced.

[0182] In one embodiment, the resistivity of the first conductive structure 104 is not greater than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. In this case, the contact portion between the first conductive structure 104 and the adhesion structure 212 is equivalent to a part of the contact area between the contact structure 108 and the electrode cover layer 102, which further reduces the contact resistance.

[0183] Furthermore, the resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210. For example, the doping concentration of the adhesion structure 212 is not less than the doping concentration of the electrode covering structure 210. The resistivity of the first conductive structure 104 is not less than the resistivity of the adhesion structure 212. For example, the doping concentration of the first conductive structure 104 is not greater than the doping concentration of the adhesion structure 212. In this case, the contact area between the contact structure 108 and the electrode covering layer 102 is equivalent to the contact area between the adhesion structure 212 and the electrode covering structure 210, thereby reducing the contact resistance.

[0184] Furthermore, the resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210. For example, the doping concentration of the adhesion structure 212 is not less than the doping concentration of the electrode covering structure 210. The resistivity of the first conductive structure 104 is less than the resistivity of the adhesion structure 212. For example, the doping concentration of the first conductive structure 104 is greater than the doping concentration of the adhesion structure 212. In this case, the contact area between the contact structure 108 and the electrode covering layer 102 is equivalent to the contact area between the first conductive structure 104 and the adhesion structure 212 and the contact area between the contact structure 108 (first contact layer 206) and the electrode covering structure 210. While reducing the bulk resistance of the contact structure 108, the resistance value of the contact resistance is also reduced.

[0185] See Figure 13In one embodiment, the lower surface of the first contact layer 206 is flush with the lower surface of the adhesion structure 212, the first conductive layer 404 is located within the adhesion structure 212, and the first barrier layer 402 is located between the first conductive layer 404 and the adhesion structure 212, and between the first conductive layer 404 and the electrode cover structure 210. Furthermore, the upper surface of the first contact layer 206 is flush with the upper surface of the adhesion structure 212. By providing the adhesion structure 212, the adhesion between the first conductive structure 104 and the electrode cover layer 102 is increased, while the contact area between the contact structure 108 and the electrode cover layer 102 is increased, thereby reducing the contact resistance.

[0186] Furthermore, the resistivity of the first conductive structure 104 is not greater than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. The resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210. For example, the doping concentration of the adhesion structure 212 is not less than the doping concentration of the electrode covering structure 210. In this case, the contact portion between the first conductive structure 104 and the adhesion structure 212, the contact portion between the first contact layer 206 and the adhesion structure 212, and the contact portion between the first contact layer 206 and the electrode covering layer 102 together constitute the contact area between the contact structure 108 and the electrode covering layer 102, further reducing the contact resistance.

[0187] Furthermore, the resistivity of the first conductive structure 104 is less than that of the adhesive structure 212. For example, the doping concentration of the first conductive structure 104 is greater than that of the adhesive structure 212, which further reduces the bulk resistance of the contact structure 108.

[0188] See Figure 15 In one embodiment, the lower surface of the first contact layer 206 is lower than the lower surface of the adhesion structure 212. The first conductive layer 404 includes a portion located within the adhesion structure 212 and a portion located within the electrode covering structure 210. The first barrier layer 402 is located between the first conductive layer 404 and the adhesion structure 212, and between the first conductive layer 404 and the electrode covering structure 210. That is, the bottom of the first contact hole 302 rests inside the electrode covering structure 210. Furthermore, the upper surface of the first contact layer 206 is flush with the upper surface of the adhesion structure 212. By providing the adhesion structure 212, the adhesion between the first conductive structure 104 and the electrode covering layer 102 is increased, while the contact area between the contact structure 108 and the electrode covering layer 102 is increased, thereby reducing the contact resistance.

[0189] Furthermore, the resistivity of the first conductive structure 104 is not greater than the resistivity of the first contact layer 206. For example, the doping concentration of the first conductive structure 104 is not less than the doping concentration of the first contact layer 206. In this case, the contact portion between the first conductive structure 104 and the adhesion structure 212, the contact portion between the first contact layer 206 and the adhesion structure 212, and the contact portion between the first contact layer 206 and the electrode cover layer 102 together constitute the contact area between the contact structure 108 and the electrode cover layer 102, which further increases the contact area, reduces the contact resistance, and at the same time reduces the bulk resistance of the contact structure 108. Furthermore, the resistivity of the adhesion structure 212 is not greater than the resistivity of the electrode covering structure 210, and the resistivity of the adhesion structure 212 is less than the resistivity of the first conductive structure 104. At this time, the contact portion between the adhesion structure 212 and the electrode covering structure 210, and the contact portion between the first contact layer 206 and the electrode covering layer 102 together constitute the contact area between the contact structure 108 and the electrode covering layer 102, which further increases the contact area, reduces the contact resistance value and the volume resistance of the contact structure 108.

[0190] In one embodiment, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the first conductive structure 104. During the operation of the semiconductor structure, the temperature of the device will rise. By setting the coefficient of thermal expansion of the first contact layer 206 to be no greater than the coefficient of thermal expansion of the first conductive structure 104, the abnormality of cracks appearing and extending at the contact surface between the first contact layer 206 and the first conductive structure 104 caused by the mismatch of thermal expansion coefficients is avoided.

[0191] Furthermore, the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the adhesive structure 212, and the coefficient of thermal expansion of the first contact layer 206 is not greater than the coefficient of thermal expansion of the electrode cover layer 102. This setting avoids the abnormality of cracks and extensions between the first contact layer 206 and the adhesive structure 212 and / or between the first contact layer 206 and the electrode cover layer 102 caused by the mismatch of thermal expansion coefficients.

[0192] In one embodiment, the first conductive structure 104, the first conductive layer 404, and the second conductive layer 408 are all first material layers, and the first material layer includes at least one of tungsten material layer, tungsten silicon material layer, tungsten nitride material layer, and tungsten silicon nitride material layer.

[0193] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above 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.

[0194] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A semiconductor structure, characterized in that, include: Electrode capping layer, located on the substrate; A first conductive structure is located on the upper surface of the electrode cover layer; The contact structure includes a first contact layer and a second contact layer, wherein the first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer; the width of the first contact layer is greater than the width of the bottom of the second contact layer. Wherein, the lower surface of the contact structure is not lower than the lower surface of the electrode covering layer, and the resistivity of the first conductive structure is not greater than the resistivity of the contact structure and not greater than the resistivity of the electrode covering layer; The first contact layer is located on the lower surface of the first conductive structure; the semiconductor structure further includes an insulating layer, which is located on the upper surface of the first conductive structure. The first contact layer includes a first conductive layer and a first barrier layer, wherein the first conductive layer is located within the electrode cover layer and the first barrier layer is located between the first conductive layer and the electrode cover layer; The second contact layer includes a second conductive layer and a second barrier layer. The second conductive layer includes a portion located within the insulating layer and a portion located within the first conductive structure. The second barrier layer is located between the second conductive layer and the insulating layer, between the second conductive layer and the first conductive structure, and between the second conductive layer and the first conductive layer.

2. The semiconductor structure according to claim 1, characterized in that, The first contact layer is located on the upper surface of the first conductive structure, and the coefficient of thermal expansion of the first contact layer is not greater than the coefficient of thermal expansion of the first conductive structure.

3. The semiconductor structure according to claim 2, characterized in that, The semiconductor structure further includes an insulating layer located on the upper surface of the first conductive structure; The first contact layer includes a first conductive layer and a first barrier layer. The first conductive layer is located within the insulating layer, and the first barrier layer is located between the first conductive layer and the insulating layer, and between the first conductive layer and the first conductive structure. The second contact layer includes a second conductive layer and a second barrier layer. The second conductive layer is located within the insulating layer, and the second barrier layer is located between the second conductive layer and the insulating layer, and between the second conductive layer and the first conductive layer.

4. The semiconductor structure according to claim 1, characterized in that, The electrode covering layer includes: Electrode covering structure, located on the substrate; An adhesion structure is located on the upper surface of the electrode covering structure.

5. The semiconductor structure according to claim 4, characterized in that, The lower surface of the first contact layer is higher than the lower surface of the adhesive structure, the first conductive layer is located inside the adhesive structure, and the first barrier layer is located between the first conductive layer and the adhesive structure. Wherein, the doping concentration of the adhesion structure is not less than the doping concentration of the electrode covering structure, and the doping concentration of the first conductive structure is not greater than the doping concentration of the adhesion structure.

6. The semiconductor structure according to claim 4, characterized in that, The lower surface of the first contact layer is flush with the lower surface of the adhesive structure, the first conductive layer is located within the adhesive structure, and the first barrier layer is located between the first conductive layer and the adhesive structure and between the first conductive layer and the electrode covering structure.

7. The semiconductor structure according to claim 4, characterized in that, The lower surface of the first contact layer is lower than the lower surface of the adhesive structure. The first conductive layer includes a portion located within the adhesive structure and a portion located within the electrode covering structure. The first barrier layer is located between the first conductive layer and the adhesive structure and between the first conductive layer and the electrode covering structure.

8. The semiconductor structure according to any one of claims 1-7, characterized in that, Also includes: A metal interconnect layer is located on the contact structure and is in contact with the top of the contact structure; The first conductive structure, the first conductive layer, and the second conductive layer are all first material layers, and the first material layer includes at least one of the following: a tungsten material layer, a tungsten-silicon material layer, a tungsten nitride material layer, and a tungsten-silicon nitride material layer.

9. A method for preparing a semiconductor structure as described in claim 1, characterized in that, include: An electrode capping layer is formed on the substrate; A first conductive structure is formed on the upper surface of the electrode cover layer; An insulating layer is formed on the first conductive structure, and a contact structure is formed within the insulating layer; The contact structure includes a first contact layer and a second contact layer. The first contact layer is in contact with the first conductive structure, and the bottom of the second contact layer is in contact with the top of the first contact layer. The width of the first contact layer is greater than the width of the bottom of the second contact layer. The lower surface of the contact structure is not lower than the lower surface of the electrode cover layer. The resistivity of the first conductive structure is not greater than the resistivity of the contact structure and is not greater than the resistivity of the electrode cover layer.

10. The preparation method according to claim 9, characterized in that, The insulating layer includes a first insulating layer and a second insulating layer, and the step of forming an insulating layer on the first conductive structure and forming a contact structure within the insulating layer includes: A first insulating layer is formed on the upper surface of the first conductive structure; A first contact hole is formed within the first insulating layer; The first contact layer is formed within the first contact hole; A second insulating layer is formed on the upper surface of the first insulating layer and the upper surface of the first contact layer; A second contact hole is formed in the second insulating layer, the second contact hole exposes the first contact layer, and the width of the bottom of the second contact hole is smaller than the width of the first contact layer; The second contact layer is formed in the second contact hole.

11. The preparation method according to claim 9 or 10, characterized in that, Also includes: A metal interconnect layer is formed on the insulating layer, and the metal interconnect layer is in contact with the top of the contact structure; Wherein, the first conductive structure, the first contact layer, and the second contact layer are all first material layers, and the first material layer includes at least one of tungsten material layer, tungsten silicon material layer, tungsten nitride material layer, and tungsten silicon nitride material layer; the thermal expansion coefficient of the first contact layer is not greater than the thermal expansion coefficient of the first conductive structure.

12. A method for preparing a semiconductor structure as described in claim 1, characterized in that, include: An electrode capping layer is formed on the substrate; A first contact layer is formed within the electrode cover layer; A first conductive structure is formed on the upper surface of the electrode cover layer and the upper surface of the first contact layer; An insulating layer is formed on the first conductive structure; A second contact layer is formed in the insulating layer and the first conductive structure, wherein the bottom of the second contact layer is in contact with the top of the first contact layer; The contact structure includes a first contact layer and a second contact layer, wherein the width of the first contact layer is greater than the width of the bottom of the second contact layer; the lower surface of the contact structure is not lower than the lower surface of the electrode cover layer, and the resistivity of the first conductive structure is not greater than the resistivity of the contact structure and not greater than the resistivity of the electrode cover layer.

13. The preparation method according to claim 12, characterized in that, The electrode capping layer comprises: an electrode capping structure and an adhesion structure stacked sequentially from the substrate, wherein the step of forming the electrode capping layer on the substrate includes: An electrode covering structure is formed on the substrate; An adhesion structure is formed on the upper surface of the electrode covering structure.

14. The preparation method according to claim 13, characterized in that, The step of forming the first contact layer within the electrode capping layer includes: A first contact hole is formed within the adhesive structure, the bottom of the first contact hole being higher than the lower surface of the adhesive structure; The first contact layer is formed within the first contact hole; Wherein, the doping concentration of the adhesion structure is not less than the doping concentration of the electrode covering structure, and the doping concentration of the first conductive structure is not greater than the doping concentration of the adhesion structure.

15. The preparation method according to claim 13, characterized in that, The step of forming the first contact layer within the electrode capping layer includes: A first contact hole is formed within the adhesion structure, the first contact hole exposing the upper surface of the electrode cover structure; The first contact layer is formed within the first contact hole.

16. The preparation method according to claim 13, characterized in that, The step of forming the first contact layer within the electrode capping layer includes: A first contact hole is formed in the adhesion structure and the electrode covering structure, the first contact hole penetrating the adhesion structure and extending into the electrode covering layer; The first contact layer is formed within the first contact hole.

17. The preparation method according to any one of claims 12 to 16, characterized in that, Also includes: A metal interconnect layer is formed on the insulating layer, and the metal interconnect layer is in contact with the top of the contact structure; Wherein, the first conductive structure, the first contact layer, and the second contact layer are all first material layers, and the first material layer includes at least one of tungsten material layer, tungsten silicon material layer, tungsten nitride material layer, and tungsten silicon nitride material layer; the thermal expansion coefficient of the first contact layer is not greater than the thermal expansion coefficient of the first conductive structure.

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