Semiconductor structure and its preparation method
By alternating ring-shaped dielectric and electrode layers in a semiconductor structure, increasing the relative area of the electrode layers, and stacking them horizontally, the process complexity and stability issues caused by the increased aspect ratio of capacitors in DRAM memory cells are solved, achieving capacitors with high capacitance and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGXIN MEMORY TECH INC
- Filing Date
- 2023-05-16
- Publication Date
- 2026-07-17
AI Technical Summary
In the existing technology, as the size of DRAM memory cells shrinks, the aspect ratio of capacitors increases, leading to increased process complexity and affecting device stability, making it difficult to achieve high capacitance values for capacitors.
By forming alternating ring-shaped dielectric and electrode layers in a semiconductor structure, the relative area of the electrode layers is increased, and they are stacked in a horizontal direction to reduce the height of the capacitor and improve structural stability.
While meeting the capacitance requirements, the height of the capacitor was reduced, thereby improving the capacitance and structural stability.
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Figure CN116347973B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of semiconductors, and more particularly to a semiconductor structure and a method for preparing the same. Background Technology
[0002] With the continuous advancement of Dynamic Random Access Memory (DRAM) design, the size of memory cells is becoming increasingly smaller. To ensure that capacitors maintain sufficient capacitance to meet data storage requirements, improvements are needed in aspects such as capacitor height, shape, and dielectric layer materials. As integration density increases, the aspect ratio of capacitors also increases. Excessively high aspect ratios can increase manufacturing complexity and pose potential risks to device stability.
[0003] Therefore, providing a capacitor that is simple to manufacture, has a low aspect ratio, and high capacitance is a problem that needs to be solved. Summary of the Invention
[0004] The technical problem to be solved by this disclosure is to reduce process complexity, increase capacitor capacitance, and provide a semiconductor structure and its fabrication method.
[0005] To address the aforementioned problems, this disclosure provides a method for fabricating a semiconductor structure, comprising: providing a first conductive contact layer; forming a columnar electrode layer on the upper surface of the first conductive contact layer; forming a first annular dielectric layer, a second annular electrode layer, and a third annular dielectric layer arranged radially along the columnar electrode layer on the side surface of the columnar electrode layer, wherein the second annular electrode layer is insulated from the first conductive contact layer; forming at least one loop unit on the side surface of the second annular dielectric layer, the loop unit comprising a first annular electrode layer, a third annular dielectric layer, and a fourth annular dielectric layer arranged radially along the columnar electrode layer, wherein the... The first annular electrode layer is in contact with the first conductive contact layer, and the third annular electrode layer is insulated from the first conductive contact layer; the top of the columnar electrode layer and the first annular electrode layer is removed to form a trench; a top dielectric layer is formed in the trench, the columnar electrode layer and the first annular electrode layer serve as the first electrode layer, the second annular electrode layer and the third annular electrode layer serve as the second electrode layer, and the second electrode layer, together with the first electrode layer and the first annular dielectric layer or the second annular dielectric layer, constitute a capacitor; a second conductive contact layer is formed, which covers the second electrode layer and the top dielectric layer.
[0006] In some embodiments, the step of forming the columnar electrode layer includes: forming a first sacrificial layer on the upper surface of the first conductive contact layer, the first sacrificial layer having a first via, the first via exposing a portion of the first conductive contact layer; forming the columnar electrode layer within the first via; and removing the first sacrificial layer to expose the first conductive contact layer and the columnar electrode layer.
[0007] In some embodiments, the step of forming a first annular dielectric layer, a second annular electrode layer, and a second annular dielectric layer arranged radially along the columnar electrode layer on the side surface of the columnar electrode layer includes: forming a first dielectric material layer on the side surface of the columnar electrode layer and at least a portion of the upper surface of the first conductive contact layer; forming a second annular electrode layer on the side surface of the first dielectric material layer, wherein the first dielectric material layer is present between the bottom surface of the second annular electrode layer and the upper surface of the first conductive contact layer; forming a second dielectric material layer on the top surface of the first dielectric material layer and the side surface of the second annular electrode layer; removing the second dielectric material layer on the upper surface of the first conductive contact layer and the second dielectric material layer on the top surface of the columnar electrode layer and the second annular electrode layer, and the first dielectric layer, retaining the first dielectric material layer on the side surface of the columnar electrode layer as the first annular dielectric layer, and retaining the second dielectric layer on the side surface of the second annular electrode layer as the second annular dielectric layer.
[0008] In some embodiments, the step of forming a second annular electrode layer on the side surface of the first dielectric material layer includes: depositing a second electrode material layer on the surface of the first dielectric material layer; removing the second electrode material from the top surface of the first dielectric material layer, and retaining the second electrode material layer on the side surface of the first dielectric material layer as the second annular electrode layer.
[0009] In some embodiments, the step of forming at least one loop unit on the side surface of the second annular dielectric layer includes: forming a first annular electrode layer on the side surface of the second annular dielectric layer, the first annular electrode layer being in contact with the first conductive contact layer; forming a third annular dielectric layer on the side surface of the first annular electrode layer and at least a portion of the upper surface of the first conductive contact layer; forming a third annular electrode layer on the side surface of the third annular dielectric layer, the third annular dielectric layer being present between the bottom surface of the third annular electrode layer and the upper surface of the first conductive contact layer; and forming a fourth annular dielectric layer on the side surface of the third annular electrode layer to obtain one loop unit.
[0010] In some embodiments, the step of forming at least one loop unit on the side surface of the second annular dielectric layer includes: forming at least one initial loop unit; thinning the initial loop unit to form the loop unit; the step of forming at least one initial loop unit includes: depositing a first electrode material layer on the surface of the second annular dielectric layer, wherein the first electrode material layer is in contact with the first conductive contact layer; depositing a third dielectric material layer on the surface of the first electrode material layer and at least a portion of the upper surface of the first conductive contact layer, depositing a third electrode material layer on the surface of the third dielectric layer, wherein the third dielectric material layer is disposed between the third electrode material layer and the first conductive contact layer, depositing a fourth dielectric material layer on the surface of the third electrode material layer and at least a portion of the upper surface of the first conductive contact layer; removing the fourth dielectric material layer from the top surface of the third electrode material layer and the upper surface of the first conductive contact layer to form one initial loop unit.
[0011] To address the aforementioned problems, this disclosure provides a semiconductor structure, characterized by comprising: a first conductive contact layer; a columnar electrode layer located on the upper surface of the first conductive contact layer; a first annular dielectric layer, a second annular electrode layer, and a second annular dielectric layer arranged radially along the columnar electrode layer, wherein the second annular electrode layer is insulated from the first conductive contact layer; at least one circulation unit located on the side surface of the second annular dielectric layer, the circulation unit comprising a first annular electrode layer, a third annular dielectric layer, and a fourth annular dielectric layer arranged radially along the columnar electrode layer, wherein the first annular electrode layer is in contact with the first conductive contact layer, and the second annular electrode layer is insulated from the first conductive contact layer, wherein the columnar electrode layer and the first annular electrode layer serve as a first electrode layer, and the second annular electrode layer and the third annular electrode layer serve as a second electrode layer, wherein the second electrode layer, the first electrode layer, and the first annular dielectric layer or the second annular dielectric layer constitute a capacitor; a top dielectric layer located on the top surface of the first electrode layer; and a second conductive contact layer covering the top surface of the second electrode layer and the top dielectric layer.
[0012] In some embodiments, the first annular electrode layer and the second annular electrode layer have the same thickness along the radial direction of the columnar electrode layer; the diameter of the columnar electrode layer is greater than the thickness of the first annular electrode layer along the radial direction of the columnar electrode layer.
[0013] In some embodiments, the first annular dielectric layer is further located between the second annular electrode layer and the first conductive contact layer, and the third annular dielectric layer is further located between the third annular electrode layer and the first conductive contact layer.
[0014] In some embodiments, the top surfaces of the columnar electrode layer and the first annular electrode layer are flush, and the top surfaces of the second annular electrode layer and the third annular electrode layer are flush.
[0015] The semiconductor structure fabrication method described in this disclosure increases the relative area between the first and second electrode layers by forming alternating annular first and second electrode layers, thereby increasing the capacitance value of the capacitor. Furthermore, the first and second electrode layers are stacked horizontally, which reduces the height of the capacitor while meeting capacitance requirements, thus improving structural stability.
[0016] The semiconductor structure described in this disclosure increases the relative area of the first and second electrode layers by alternately arranging annular first and second electrode layers, thereby increasing the capacitance value of the capacitor. Furthermore, the first and second electrode layers are stacked horizontally, which reduces the height of the capacitor while meeting capacitance requirements, thus improving structural stability.
[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are only some specific embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.
[0019] Figure 1 This is a schematic diagram of the structure of a capacitor in the prior art.
[0020] Figure 2 This is a flowchart illustrating the steps of an embodiment of the semiconductor structure fabrication method described in this disclosure.
[0021] Figures 3A to 3O This is a process flow diagram of one embodiment of the semiconductor structure fabrication method described in this disclosure.
[0022] Figures 4A to 4O for Figures 3A to 3O A sectional view along the AA' direction.
[0023] Figures 5A to 5D This is a process flow diagram of another embodiment of the semiconductor structure fabrication method described in this disclosure.
[0024] Figures 6A to 6D for Figures 5A to 5D A cross-sectional view along the BB' direction. Detailed Implementation
[0025] The specific embodiments of the semiconductor structure and its preparation method provided in this disclosure are described in detail below with reference to the accompanying drawings.
[0026] Figure 1 This is a schematic diagram of the structure of a capacitor. Figure 1 As shown, the capacitor includes a lower electrode 11, a dielectric layer 12, and an upper electrode 13. The lower electrode 11, dielectric layer 12, and upper electrode 13 form a folded structure in the vertical direction. As chip size shrinks, the aspect ratio of the capacitor will become increasingly higher, and the manufacturing process will become more complex.
[0027] To address the aforementioned problems, this disclosure provides a method for fabricating a semiconductor structure. Figure 2 This is a flowchart illustrating the steps of an embodiment of the semiconductor structure fabrication method disclosed herein. The fabrication method includes: step S21, providing a first conductive contact layer; step S22, forming a columnar electrode layer on the upper surface of the first conductive contact layer; step S23, forming a first annular dielectric layer, a second annular electrode layer, and a third annular dielectric layer arranged radially along the columnar electrode layer on the side surface of the columnar electrode layer, wherein the second annular electrode layer is insulated from the first conductive contact layer; and step S24, forming at least one loop unit on the side surface of the second annular dielectric layer, the loop unit including a first annular electrode layer, a third annular dielectric layer, and a third annular dielectric layer arranged radially along the columnar electrode layer. The first annular electrode layer and the fourth annular dielectric layer are in contact with the first conductive contact layer, and the third annular electrode layer is insulated from the first conductive contact layer; Step S25, the top of the columnar electrode layer and the first annular electrode layer are removed to form a trench; Step S26, a top dielectric layer is formed in the trench, the columnar electrode layer and the first annular electrode layer serve as the first electrode layer, the second annular electrode layer and the third annular electrode layer serve as the second electrode layer, and the second electrode layer, the first electrode layer and the first annular dielectric layer or the second annular dielectric layer constitute a capacitor; Step S27, a second conductive contact layer is formed, which covers the second electrode layer and the top dielectric layer.
[0028] Figures 3A to 3O This disclosure includes a process flow diagram of an embodiment of a semiconductor structure fabrication method. Figures 4A to 4O They are respectively Figures 3A to 3O A cross-sectional view along the AA' direction, wherein, Figure 3O The invisible parts of the middle surface are represented by dashed lines.
[0029] Please refer to Figure 3A and Figure 4AAnd in step S21, a first conductive contact layer 301 is provided. In this embodiment, the material of the first conductive contact layer 301 is tungsten metal. In other embodiments, the material of the first conductive contact layer 301 may also be titanium nitride, metal silicide, copper, or copper-tungsten alloy.
[0030] Please refer to Figure 3D and Figure 4D And in step S22, a columnar electrode layer 300 is formed on the upper surface of the first conductive contact layer 301. Please refer to... Figures 3B to 3D as well as Figures 4B to 4D This disclosure provides a method for forming a columnar electrode layer 300, comprising the following steps:
[0031] like Figure 3B and Figure 4B As shown, a first sacrificial layer 391 is formed on the upper surface of the first conductive contact layer 300. The first sacrificial layer 391 has a first via 392, which exposes a portion of the first conductive contact layer 301. In some embodiments, the method for forming the first sacrificial layer 391 includes, but is not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The first sacrificial layer 391 may be a silicon oxide layer.
[0032] like Figure 3C and Figure 4C As shown, a columnar electrode layer 300 is formed within the first via 392. In some embodiments, the columnar electrode layer 300 can be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the columnar electrode layer 300 is titanium nitride. In other embodiments, the material of the columnar electrode layer 300 can also be metal silicide, copper, tungsten, or copper-tungsten alloys. The diameter of the columnar electrode layer 300 can be 8 to 12 nanometers.
[0033] like Figure 3D and Figure 4D As shown, the first sacrificial layer 391 is removed, exposing the first conductive contact layer 301 and the columnar electrode layer 300.
[0034] After completing the above steps, you will get Figure 3D and Figure 4D The columnar electrode layer 300 shown.
[0035] Please refer to Figure 3H and Figure 4H In step S23, a first annular dielectric layer 311, a second annular electrode layer 320, and a second annular dielectric layer 321 are formed on the side surface of the columnar electrode layer 300, arranged radially along the columnar electrode layer 300. The second annular electrode layer 320 is insulated from the first conductive contact layer 301, and the first annular dielectric layer 311 is located between the second annular electrode layer 320 and the first conductive contact layer 301.
[0036] Please refer to Figures 3E to 3H as well as Figures 4E to 4H This disclosure provides a method for forming a first annular dielectric layer 311, a second annular electrode layer 320, and a second annular dielectric layer 321 arranged radially along the side surface of a columnar electrode layer 300, comprising the following steps:
[0037] like Figure 3E and Figure 4E As shown, a first dielectric material layer 313 is formed on the side surface of the columnar electrode layer 300 and at least a portion of the upper surface of the first conductive contact layer 301. In some embodiments, the methods for forming the first dielectric material layer 313 include, but are not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The material of the first dielectric material layer 313 is a high-k material, including but not limited to alumina, zirconium oxide, and titanium oxide. The thickness of the first dielectric material layer 313 along the radial direction of the columnar electrode layer 300 can be 4 to 8 nanometers.
[0038] like Figure 3F and Figure 4F As shown, a second annular electrode layer 320 is formed on the side surface of the first dielectric material layer 313, and the first dielectric material layer 313 is located between the bottom surface of the second annular electrode layer 320 and the upper surface of the first conductive contact layer 301. In some embodiments, the step of forming the second annular electrode layer 320 on the side surface of the first dielectric material layer 313 includes:
[0039] A second electrode material layer is deposited on the surface of the first dielectric material layer 313. In some embodiments, the second electrode material layer may be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the second electrode material layer is tungsten. In other embodiments, the material of the second electrode material layer may also be titanium nitride, metal silicide, copper, or copper-tungsten alloy.
[0040] The second electrode material on the top surface of the first dielectric material layer 313 is removed, and the second electrode material layer on the side surface of the first dielectric material layer 313 is retained as the second annular electrode layer 320. The thickness of the second annular electrode layer 320 along the radial direction of the columnar electrode layer 300 can be 3 to 7 nanometers.
[0041] like Figure 3G and Figure 4GAs shown, a second dielectric material layer 323 is formed on the side surface of the second annular electrode layer 320. In some embodiments, the method for forming the second dielectric material layer 323 includes, but is not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The second dielectric material layer 323 covers the surfaces of the first dielectric material layer 313 and the second annular electrode layer 320. The material of the second dielectric layer 323 is a high-k material, including but not limited to alumina, zirconium oxide, and titanium oxide. The thickness of the second dielectric layer 323 along the radial direction of the columnar electrode layer 300 can be 4 to 8 nanometers.
[0042] like Figure 3H and Figure 4H As shown, the second dielectric material layer 323 and the first dielectric material layer 313 on the upper surface of the first conductive contact layer 301, the second dielectric material layer 323 and the first dielectric layer 313 on the top surface of the columnar electrode layer 300 and the second annular electrode layer 320 are removed, the first dielectric material layer 313 on the side of the columnar electrode layer 300 is retained as the first annular dielectric layer 311, and the second dielectric material layer 323 on the side surface of the second annular electrode layer 320 is retained as the second annular dielectric layer 321.
[0043] After completing the above steps, you will get the following: Figure 3H and Figure 4H The first annular dielectric layer 311, the second annular electrode layer 320, and the second annular dielectric layer 321 are shown.
[0044] Please refer to Figure 3L and Figure 4L In step S24, at least one loop unit 33 is formed on the side surface of the second annular dielectric layer 321. The loop unit 33 includes a first annular electrode layer 310, a third annular dielectric layer 331, a third annular electrode layer 330, and a fourth annular dielectric layer 341 arranged radially along the columnar electrode layer 300. The first annular electrode layer 310 is in contact with the first conductive contact layer 301, the third annular electrode layer 330 is insulated from the first conductive contact layer 301, and the third annular dielectric layer 331 is also located between the third annular electrode layer 330 and the first conductive contact layer 301.
[0045] Please refer to Figures 3I to 3L as well as Figures 4I to 4L This disclosure provides a method for forming at least one loop unit 33 on the side surface of a second annular dielectric layer 321, comprising the following steps:
[0046] like Figure 3I and Figure 4IAs shown, a first annular electrode layer 310 is formed on the side surface of the second annular dielectric layer 321, and the first annular electrode layer 310 is in contact with the first conductive contact layer 301. In some embodiments, the first annular electrode layer 310 can be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the first annular electrode layer 310 is titanium nitride. In other embodiments, the material of the first annular electrode layer 310 can also be metal silicide, copper, tungsten, or copper-tungsten alloy. The thickness of the first annular electrode layer 310 along the radial direction of the columnar electrode layer 300 can be 3 to 7 nanometers.
[0047] like Figure 3J and Figure 4J As shown, a third annular dielectric layer 331 is formed on the side surface of the first annular electrode layer 310 and at least a portion of the upper surface of the first conductive contact layer 301. In some embodiments, the method for forming the third annular dielectric layer 331 includes, but is not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The material of the third annular dielectric layer 331 is a high-k material, including but not limited to alumina, zirconium oxide, and titanium oxide. The thickness of the third annular dielectric layer 331 along the radial direction of the columnar electrode layer 300 can be 4 to 8 nanometers.
[0048] like Figure 3K and Figure 4K As shown, a third annular electrode layer 330 is formed on the side surface of the third annular dielectric layer 331, and the third annular dielectric layer 331 is located between the bottom surface of the third annular electrode layer 330 and the upper surface of the first conductive contact layer 301. In some embodiments, the third annular electrode layer 330 can be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the third annular electrode layer 330 is tungsten. In other embodiments, the material of the third annular electrode layer 330 can also be titanium nitride, metal silicide, copper, or copper-tungsten alloy. The thickness of the third annular electrode layer 330 along the radial direction of the columnar electrode layer 300 can be 3 to 7 nanometers.
[0049] like Figure 3L and Figure 4L As shown, a fourth annular dielectric layer 341 is formed on the side surface of the third annular electrode layer 330 to obtain a cycle unit 33. In some embodiments, the method for forming the fourth annular dielectric layer 341 includes, but is not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The material of the fourth annular dielectric layer 341 is a high-k material, including but not limited to alumina, zirconium oxide, and titanium oxide. The thickness of the fourth annular dielectric layer 341 along the radial direction of the columnar electrode layer 300 can be 4 to 8 nanometers.
[0050] After completing the above steps, you will get Figure 4L The loop unit 33 shown.
[0051] Please refer to Figure 3M and Figure 4M In step S25, the tops of the columnar electrode layer 300 and the first annular electrode layer 310 are removed, such that the top surfaces of the remaining columnar electrode layer 300 and the first annular electrode layer 310 are lower than the top surfaces of the first annular electrode layer 310, the second annular electrode layer 320, and the third annular electrode layer 330, to form a trench 393. In some embodiments, the columnar electrode layer 300 and the first annular electrode layer 310 are selectively etched using an etching solution to form the trench. In this embodiment, the columnar electrode layer 300 and the first annular electrode layer 310 are etched using a sulfuric acid-hydrogen peroxide mixture solution containing additives. Since the materials of the second annular electrode layer 320 and the third annular electrode layer 330 are different from those of the columnar electrode layer 300 and the first annular electrode layer 310, solution etching can achieve etching only the columnar electrode layer 300 and the first annular electrode layer 310 without affecting the second annular electrode layer 320 and the third annular electrode layer 330.
[0052] Please refer to Figure 3N and Figure 4N In step S26, a top dielectric layer 35 is formed within the trench 393. A columnar electrode layer 300 and a first annular electrode layer 310 serve as the first electrode layer 31, and a second annular electrode layer 320 and a third annular electrode layer 330 serve as the second electrode layer 32. The second electrode layer 32, together with the first electrode layer 31 and either the first annular dielectric layer 311 or the second annular dielectric layer 321, constitute a capacitor. In some embodiments, the method for forming the top dielectric layer 35 includes, but is not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The material of the top dielectric layer 35 is a high-k material, including but not limited to alumina, zirconium oxide, and titanium oxide.
[0053] Please refer to Figure 3O and Figure 4OIn step S27, a second conductive contact layer 302 is formed, which covers the second electrode layer 32 and the top dielectric layer 35. In some embodiments, the second conductive contact layer 302 can be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the second conductive contact layer 302 is tungsten. In other embodiments, the material of the second conductive contact layer 302 can also be titanium nitride, metal silicide, copper, or copper-tungsten alloy. In some embodiments, due to the etching load effect, the top surface of the columnar electrode layer 300 is lower than the top surface of the first annular electrode layer 310, and the top dielectric layer 35 located on the top surfaces of the columnar electrode layer 300 and the first annular electrode layer 310 has the same thickness. Therefore, the bottom surface of the formed second conductive contact layer 302 is non-planar. The bottom surface of the second conductive contact layer 302 includes a first region that contacts the top dielectric layer 35 on the columnar electrode layer 300 and a second region that contacts the top dielectric layer 35 on the first annular electrode layer 310. The bottom surface of the second conductive contact layer 302 located in the first region may be lower than the bottom surface of the second conductive contact layer 302 located in the second region. The second conductive contact layer 302 is self-aligned and embedded in the electrode and dielectric layer structure, which improves the stability of the semiconductor structure.
[0054] By completing the above steps, this disclosure can be obtained. Figure 3O and Figure 4O The semiconductor structure shown, wherein, Figure 3O The invisible parts of the middle surface are represented by dashed lines.
[0055] The semiconductor structure fabrication method disclosed herein increases the relative area of the first and second electrode layers by forming a ring-shaped alternating first electrode layer and a second electrode layer, thereby increasing the capacitance value of the capacitor. Furthermore, the first and second electrode layers are stacked horizontally, which reduces the height of the capacitor while meeting capacitance requirements, thus improving structural stability.
[0056] This disclosure also proposes another embodiment in which at least one cyclic unit 33 is formed on the side surface of the second annular dielectric layer 321.
[0057] Figures 5A to 5D This is a process flow diagram of another embodiment of the semiconductor structure fabrication method disclosed herein. Figures 6A to 6D for Figures 5A to 5D A cross-sectional view along the BB' direction. For example... Figures 5A to 5D as well as Figures 6A-6D As shown, forming at least one loop unit 33 on the side surface of the second annular dielectric layer 321 further includes the following steps:
[0058] like Figure 5C and Figure 6C As shown, at least one initial loop unit 339 is formed. Figures 5A to 5C as well as Figures 6A-6C As shown, in some embodiments, forming at least one initial loop unit 339 includes the following steps:
[0059] like Figure 5A and Figure 6A As shown, Figure 5A Is Figure 3H Draw based on the structure shown. Figure 6A Is Figure 4H Based on the structure shown, a first electrode material layer 312 is deposited on the surface of the second annular dielectric layer 321, and the first electrode material layer 312 is in contact with the first conductive contact layer 301. In some embodiments, the first electrode material layer 312 can be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the first electrode material layer 312 is titanium nitride. In other embodiments, the material of the first electrode material layer 312 can also be metal silicide, copper, tungsten, or copper-tungsten alloy. The thickness of the first electrode material layer 312 along the radial direction of the columnar electrode layer 300 can be 3 to 7 nanometers.
[0060] like Figure 5B and Figure 6B As shown, a third dielectric material layer 333 is deposited on the surface of the first electrode material layer 312 and at least a portion of the upper surface of the first conductive contact layer 301. A third electrode material layer 332 is deposited on the surface of the third dielectric material layer 333. A third dielectric material layer 333 is disposed between the third electrode material layer 332 and the first conductive contact layer 301. A fourth dielectric material layer 343 is deposited on the surface of the third electrode material layer 332 and at least a portion of the upper surface of the first conductive contact layer 301.
[0061] In some embodiments, the methods for forming the third dielectric layer 333 and the fourth dielectric layer 343 include, but are not limited to, thermal oxidation, chemical vapor deposition, plasma chemical vapor deposition, and atomic layer deposition. The materials of the third dielectric layer 333 and the fourth dielectric layer 343 are high-k materials, including but not limited to alumina, zirconium oxide, and titanium oxide. The thickness of the third dielectric layer 333 and the fourth dielectric layer 343 along the radial direction of the columnar electrode layer 300 can be 4 to 8 nanometers.
[0062] In some embodiments, the first electrode material layer 312 may be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the first electrode material layer 313 is titanium nitride. In other embodiments, the material of the first electrode material layer 313 may also be metal silicide, copper, tungsten, or a copper-tungsten alloy. The thickness of the first electrode material layer 313 along the radial direction of the columnar electrode layer 300 may be 3 to 7 nanometers.
[0063] In some embodiments, the third electrode material layer 332 may be formed using processes such as chemical vapor deposition or atomic layer deposition. In this embodiment, the material of the third electrode material layer 332 is tungsten. In other embodiments, the material of the third electrode material layer 332 may also be titanium nitride, metal silicide, copper, or copper-tungsten alloy. The thickness of the third electrode material layer 332 along the radial direction of the columnar electrode layer 300 may be 3 to 7 nanometers.
[0064] like Figure 5C and Figure 6C As shown, the fourth dielectric material layer on the top surface of the third electrode material layer and the upper surface of the first conductive contact layer 301 is removed to form an initial cycle unit 339.
[0065] like Figure 5D and Figure 6D As shown, the initial cycling unit 339 is thinned to form the cycling unit 33. In some embodiments, the initial cycling unit 339 is thinned to a desired height using chemical mechanical polishing (CMP) to form the cycling unit 33. The thinned first electrode material layer 312 forms a first annular electrode layer 310, the thinned third dielectric material layer 313 forms a third annular dielectric layer 311, the thinned third electrode material layer 332 forms a third annular electrode layer 330, and the thinned fourth dielectric material layer 343 forms a fourth annular dielectric layer 341.
[0066] After completing the above steps, you will get the following: Figure 5D and Figure 6D The loop unit 33 shown.
[0067] Continue to complete Figures 3I to 3O as well as Figures 4I to 4O The semiconductor structure disclosed herein can be obtained by following the process flow shown.
[0068] The semiconductor structure fabrication method disclosed herein increases the relative area of the first electrode layer 31 and the second electrode layer 32 by forming a ring-shaped alternating arrangement, thereby increasing the capacitance value of the capacitor. Furthermore, the first electrode layer 31 and the second electrode layer 32 are stacked horizontally, which can reduce the height of the capacitor while meeting the capacitance requirements, thus improving structural stability.
[0069] Based on the same inventive concept, this disclosure also provides a semiconductor structure. Please refer to [link / reference]. Figures 30-40 ,in, Figure 3O The invisible parts of the middle surface are represented by dashed lines.
[0070] like Figures 30-40As shown, the semiconductor structure includes: a first conductive contact layer 301, a pillar electrode layer 300, a first annular dielectric layer 311, a second annular electrode layer 320, a second annular dielectric layer 321, a loop unit 33, a top dielectric layer 35, and a second conductive contact layer 302.
[0071] The columnar electrode layer 300 is located on the upper surface of the first conductive contact layer 301. A first annular dielectric layer 311, a second annular electrode layer 320, and a second annular dielectric layer 321 are arranged radially along the columnar electrode layer 301, and the second annular electrode layer 320 is insulated from the first conductive contact layer 301.
[0072] The circulation unit 33 is located on the side surface of the second annular dielectric layer 321. The circulation unit 33 includes a first annular electrode layer 310, a third annular dielectric layer 331, a third annular electrode layer 330, and a fourth annular dielectric layer 341 arranged radially along the columnar electrode layer 301. The first annular electrode layer 310 is in contact with the first conductive contact layer 301, and the second annular electrode layer 320 is insulated from the first conductive contact layer 301. The columnar electrode layer 300 and the first annular electrode layer 310 serve as the first electrode layer 31, and the second annular electrode layer 320 and the third annular electrode layer 330 serve as the second electrode layer 32. The second electrode layer 32, together with the first electrode layer 31 and the first annular dielectric layer 311 or the second annular dielectric layer 321, constitute a capacitor. In this embodiment, the semiconductor structure includes one circulation structure 33. In other embodiments, the semiconductor structure may also include two or more circulation structures 33, arranged sequentially outwards along the radial direction of the columnar electrode layer 300.
[0073] The top dielectric layer 35 is located on the top surface of the first electrode layer 31 and is used to isolate the first electrode layer 31 from the second conductive contact layer 302.
[0074] The second conductive contact layer 302 covers the second electrode layer 32 and the top surface of the top dielectric layer 35, and is used to electrically connect the second electrode layer 32.
[0075] The semiconductor structure disclosed herein increases the relative area of the first electrode layer 31 and the second electrode layer 32 by alternately arranging the annular first electrode layer 31 and the second electrode layer 32, thereby increasing the capacitance value of the capacitor. Furthermore, the first electrode layer 31 and the second electrode layer 32 are stacked horizontally, which can reduce the height of the capacitor while meeting the capacitance requirements, thus improving structural stability.
[0076] In this embodiment, the columnar electrode layer 300 and the first annular electrode layer 310 are made of titanium nitride. In other embodiments, the columnar electrode layer 300 and the first annular electrode layer 310 may also be made of metal silicide, copper, tungsten, or copper-tungsten alloy.
[0077] In this embodiment, the second annular electrode layer 320 and the third annular electrode layer 330 are made of tungsten. In other embodiments, the material of the second electrode layer may also be titanium nitride, metal silicide, copper, or a copper-tungsten alloy.
[0078] In some embodiments, the first annular electrode layer 310 and the second annular electrode layer 320 have equal thicknesses along the radial direction of the columnar electrode layer 300; the diameter of the columnar electrode layer 300 is greater than the thickness of the first annular electrode layer 310 along the radial direction of the columnar electrode layer 300. In this embodiment, the thicknesses of the first annular electrode layer 310 and the second annular electrode layer 320 along the radial direction of the columnar electrode layer 300 are 3 to 7 nanometers; the diameter of the columnar electrode layer 300 is 8 to 12 nanometers.
[0079] In this embodiment, the materials of the first annular dielectric layer 311, the second annular dielectric layer 321, the third annular dielectric layer 331, and the fourth annular dielectric layer 341 are high-K materials, including but not limited to alumina, zirconium oxide, and titanium oxide.
[0080] In some embodiments, the first annular dielectric layer 311, the second annular dielectric layer 321, the third annular dielectric layer 331, and the fourth annular dielectric layer 341 have equal thicknesses. In this embodiment, the thicknesses of the first annular dielectric layer 311, the second annular dielectric layer 321, the third annular dielectric layer 331, and the fourth annular dielectric layer 341 are 4 to 8 nanometers.
[0081] In some embodiments, the first annular dielectric layer 311 is further located between the second annular electrode layer 320 and the first conductive contact layer 301, and the third annular dielectric layer 331 is further located between the third annular electrode layer 330 and the first conductive contact layer 301. The first annular dielectric layer 311 is also used to insulate the second annular electrode layer 320 and the first conductive contact layer 301, and the third annular dielectric layer 331 is also used to insulate the third annular electrode layer 330 and the first conductive contact layer 301.
[0082] In some embodiments, the top surfaces of the columnar electrode layer 300 and the first annular electrode layer 310 are flush, and the top surfaces of the second annular electrode layer 320 and the third annular electrode layer 330 are flush.
[0083] It should be noted that references to "an embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc., in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure, or characteristic is described in connection with an embodiment, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.
[0084] Generally, terms can be understood at least partially from their usage in context. For example, the term "one or more," as used herein, depends at least partially on the context and can be used to describe any feature, structure, or characteristic in a singular sense, or in a plural sense, to describe a combination of features, structures, or characteristics. Similarly, terms such as "a," "a," or "the" can also be understood, at least partially on the context, to express either a singular or plural usage. Furthermore, the term "based on" can be understood not necessarily to express an exclusive set of factors, but rather, alternatively, also at least partially on the context, to allow for the presence of other factors that are not necessarily explicitly described. It should also be noted in this specification that "connection / coupling" refers not only to a direct coupling of one component to another, but also to an indirect coupling of one component to another via an intermediate component.
[0085] It should be noted that the terms "comprising" and "having," and their variations, used in this disclosure are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context. It should be understood that such data used interchangeably where appropriate. Furthermore, embodiments and features within embodiments of this disclosure can be combined with each other unless otherwise specified. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this disclosure. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar or identical parts between embodiments can be referred to mutually.
[0086] The above are merely preferred embodiments of this disclosure. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this disclosure, and these improvements and modifications should also be considered within the scope of protection of this disclosure.
Claims
1. A method for fabricating a semiconductor structure, characterized in that, include: Provide a first conductive contact layer; A columnar electrode layer is formed on the upper surface of the first conductive contact layer; A first annular dielectric layer, a second annular electrode layer, and a third annular dielectric layer are formed radially along the columnar electrode layer, with the second annular electrode layer being insulated from the first conductive contact layer. At least one circulation unit is formed on the side surface of the second annular dielectric layer, the circulation unit including a first annular electrode layer, a third annular dielectric layer, and a fourth annular dielectric layer radially along the columnar electrode layer, with the first annular electrode layer in contact with the first conductive contact layer and the third annular electrode layer being insulated from the first conductive contact layer. The tops of the columnar electrode layer and the first annular electrode layer are removed to form a trench, and the remaining top surfaces of the columnar electrode layer and the first annular electrode layer are lower than the top surfaces of the second annular electrode layer and the third annular electrode layer, with the top surface of the columnar electrode layer being lower than the top surface of the first annular electrode layer. A top dielectric layer is formed in the trench. The columnar electrode layer and the first annular electrode layer serve as the first electrode layer, and the second annular electrode layer and the third annular electrode layer serve as the second electrode layer. The second electrode layer, together with the first electrode layer and the first annular dielectric layer or the second annular dielectric layer, constitute a capacitor. A second conductive contact layer is formed, which covers the second electrode layer and the top dielectric layer.
2. The method according to claim 1, characterized in that, The step of forming the columnar electrode layer includes: forming a first sacrificial layer on the upper surface of the first conductive contact layer, the first sacrificial layer having a first via, the first via exposing a portion of the first conductive contact layer; forming the columnar electrode layer within the first via; and removing the first sacrificial layer to expose the first conductive contact layer and the columnar electrode layer.
3. The method according to claim 1, characterized in that, The step of forming a first annular dielectric layer, a second annular electrode layer, and a second annular dielectric layer arranged radially along the side surface of the columnar electrode layer includes: forming a first dielectric material layer on the side surface of the columnar electrode layer and at least a portion of the upper surface of the first conductive contact layer; forming a second annular electrode layer on the side surface of the first dielectric material layer, with the first dielectric material layer between the bottom surface of the second annular electrode layer and the upper surface of the first conductive contact layer; forming a second dielectric material layer on the top surface of the first dielectric material layer and the side surface of the second annular electrode layer; removing the second dielectric material layer and the first dielectric layer on the upper surface of the first conductive contact layer, the second dielectric material layer and the first dielectric layer on the top surface of the columnar electrode layer and the second annular electrode layer, retaining the first dielectric material layer on the side surface of the columnar electrode layer as the first annular dielectric layer, and retaining the second dielectric layer on the side surface of the second annular electrode layer as the second annular dielectric layer.
4. The method according to claim 3, characterized in that, The step of forming a second annular electrode layer on the side surface of the first dielectric material layer includes: depositing a second electrode material layer on the surface of the first dielectric material layer; removing the second electrode material from the top surface of the first dielectric material layer, and retaining the second electrode material layer on the side surface of the first dielectric material layer as the second annular electrode layer.
5. The method according to any one of claims 1 to 4, characterized in that, The step of forming at least one loop unit on the side surface of the second annular dielectric layer includes: forming a first annular electrode layer on the side surface of the second annular dielectric layer, the first annular electrode layer being in contact with the first conductive contact layer; forming a third annular dielectric layer on the side surface of the first annular electrode layer and at least a portion of the upper surface of the first conductive contact layer; forming a third annular electrode layer on the side surface of the third annular dielectric layer, the third annular dielectric layer being present between the bottom surface of the third annular electrode layer and the upper surface of the first conductive contact layer; and forming a fourth annular dielectric layer on the side surface of the third annular electrode layer to obtain one loop unit.
6. The method according to any one of claims 1 to 4, characterized in that, The step of forming at least one loop cell on the side surface of the second annular dielectric layer includes: Form at least one initial loop unit; Thin the initial loop unit to form the loop unit; The formation of at least one initial cycle unit includes: depositing a first electrode material layer on the surface of the second annular dielectric layer, wherein the first electrode material layer is in contact with the first conductive contact layer; depositing a third dielectric material layer on the surface of the first electrode material layer and at least a portion of the upper surface of the first conductive contact layer; depositing a third electrode material layer on the surface of the third dielectric material layer, wherein the third dielectric material layer is disposed between the third electrode material layer and the first conductive contact layer; and depositing a fourth dielectric material layer on the surface of the third electrode material layer and at least a portion of the upper surface of the first conductive contact layer. The fourth dielectric material layer is removed from the top surface of the third electrode material layer and the upper surface of the first conductive contact layer to form one of the initial cycle units.
7. A semiconductor structure, characterized in that, include: First conductive contact layer; A columnar electrode layer is located on the upper surface of the first conductive contact layer; A first annular dielectric layer, a second annular electrode layer, and a third annular dielectric layer are arranged radially along the columnar electrode layer, and the second annular electrode layer is insulated from the first conductive contact layer; at least one circulation unit is located on the side surface of the second annular dielectric layer, the circulation unit including a first annular electrode layer, a third annular dielectric layer, and a fourth annular dielectric layer arranged radially along the columnar electrode layer, wherein the first annular electrode layer is in contact with the first conductive contact layer, and the second annular electrode layer is insulated from the first conductive contact layer, the columnar electrode layer and the first annular electrode layer serve as a first electrode layer, the second annular electrode layer and the third annular electrode layer serve as a second electrode layer, and the second electrode layer, the first electrode layer, and the first annular dielectric layer or the second annular dielectric layer form a capacitor, wherein the top surface of the columnar electrode layer and the first annular electrode layer is lower than the top surface of the second annular electrode layer and the third annular electrode layer, and the top surface of the columnar electrode layer is lower than the top surface of the first annular electrode layer; a top dielectric layer is located on the top surface of the first electrode layer. The second conductive contact layer covers the second electrode layer and the top surface of the top dielectric layer.
8. The semiconductor structure according to claim 7, characterized in that, The first annular electrode layer and the second annular electrode layer have the same thickness along the radial direction of the columnar electrode layer; the diameter of the columnar electrode layer is greater than the thickness of the first annular electrode layer along the radial direction of the columnar electrode layer.
9. The semiconductor structure according to claim 7, characterized in that, The first annular dielectric layer is also located between the second annular electrode layer and the first conductive contact layer, and the third annular dielectric layer is also located between the third annular electrode layer and the first conductive contact layer.
10. The semiconductor structure according to claim 7, characterized in that, The top surfaces of the columnar electrode layer and the first annular electrode layer are flush, and the top surfaces of the second annular electrode layer and the third annular electrode layer are flush.