MOM capacitor structure

Abstract

The invention provides an MOM capacitor structure which comprises a plurality of insulating dielectric layers, a plurality of first main body metal wires, a plurality of second main body metal wires, a plurality of first conductive plugs and a plurality of second conductive plugs which are sequentially stacked, according to the invention, the plurality of first conductive plugs are arranged between the longitudinally stacked first main body metal wires, the plurality of second conductive plugs are arranged between the longitudinally stacked second main body metal wires, and in the same insulating medium layer, the first conductive plugs and the second conductive plugs are arranged in a dotted staggered manner. The first conductive plug, the second conductive plug and the insulating medium layer between the first conductive plug and the second conductive plug form a plurality of MOM capacitors, so that the overall capacitance density of the laminated MOM capacitor structure is improved, the stability of the capacitors is improved, and the reliability of the device is also improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a MOM capacitor structure. Background Art

[0002] MOM (metal-oxide-metal) capacitors are generally interdigitated capacitors (also called interdigitated capacitors) formed by metal wiring, where the dielectric layer in the middle of the MOM capacitor is an insulating layer between metal wires, usually made of silicon dioxide. As process nodes advance, the spacing between metal wires in the back end decreases, and the capacitance value increases. At the same time, MOM capacitors can be stacked with multiple metal layers, which greatly increases the capacitance per unit area and saves chip area. Therefore, MOM capacitors are increasingly used, and it is more important to increase the capacitance density of MOM capacitors.

[0003] At present, there are usually two structures of MOM capacitors in the back-end process of some semiconductor devices. One is a stacked capacitor, in which the metal line layout at one end of the capacitor is completely overlapped, and the metal lines of each layer at the other end are also completely overlapped; the other is a staggered layer capacitor, in which the metal line layout of the first end of the upper layer overlaps with the metal line layout of the second end of the lower layer.

[0004] Due to structural differences, stacked capacitors have lower requirements for the overlay accuracy of the upper and lower layers, while the staggered capacitor value is more affected by the exposure alignment accuracy of the upper and lower layers. As the number of stacked layers increases, the error of the staggered capacitor will increase, so stacked capacitors are usually selected for MOM capacitors in the back-end process. However, since the overlapping metal wires of the upper and lower layers of the stacked capacitor are interconnected, the overlapping metal wires of the upper and lower layers of the stacked capacitor cannot provide capacitance. Therefore, under the same process conditions, the density of the stacked capacitor is smaller than that of the staggered capacitor. Summary of the invention

[0005] The present application provides a MOM capacitor structure, which can solve the problem of insufficient capacitance density of traditional MOM stacked capacitors.

[0006] The embodiment of the present application provides a MOM capacitor structure, comprising: first to nth insulating dielectric layers, a plurality of first main metal wires, a plurality of second main metal wires, a plurality of first conductive plugs, and a plurality of second conductive plugs, wherein n is an integer greater than or equal to 3; The first to nth insulating dielectric layers are stacked in sequence, the first main metal wire and the second main metal wire are arranged in a staggered manner in a fork-shaped manner and are located in the same insulating dielectric layer, and the first conductive plug and the second conductive plug are both located in the same insulating dielectric layer, wherein the insulating dielectric layer where the first main metal wire and the second main metal wire are located is staggered and stacked with the insulating dielectric layer where the first conductive plug and the second conductive plug are located; The first conductive plug and the first main metal line are stacked in a longitudinal direction and connected to the first main metal line stacked in a longitudinal direction, and the second conductive plug and the second main metal line are stacked in a longitudinal direction and connected to the second main metal line stacked in a longitudinal direction; The first main metal line and the first conductive plug constitute a first metal interconnect structure; the second main metal line and the second conductive plug constitute a second metal interconnect structure; In the transverse direction, the plurality of first conductive plugs between the longitudinally stacked first main metal lines and the plurality of second conductive plugs between the longitudinally stacked second main metal lines are arranged in a staggered manner in a dot-like manner.

[0007] Optionally, in the MOM capacitor structure, in the longitudinal direction, multiple first conductive plugs in the upper and lower insulating dielectric layers of any one of the first main metal wires are arranged alternately; multiple second conductive plugs in the upper and lower insulating dielectric layers of any one of the second main metal wires are arranged alternately.

[0008] Optionally, in the MOM capacitor structure, the MOM capacitor structure also includes: a first end metal wire and a second end metal wire, the first end metal wire is located in the insulating dielectric layer where the first main metal wire and the second main metal wire are located and connects the left ends of all the first main metal wires; the second end metal wire is located in the insulating dielectric layer where the first main metal wire and the second main metal wire are located and connects the right ends of all the second main metal wires.

[0009] Optionally, in the MOM capacitor structure, the first end metal line, the second end metal line, the first main metal line, the second main metal line, the first conductive plug and the second conductive plug are all made of copper.

[0010] Optionally, in the MOM capacitor structure, the insulating dielectric layer is made of silicon dioxide.

[0011] Optionally, in the MOM capacitor structure, in the insulating dielectric layer where the first main metal line and the second main metal line are located, the line width of the first main metal line and the second main metal line, and the spacing between the first main metal line and the second main metal line both comply with the minimum design rules.

[0012] The technical solution of this application has at least the following advantages: In the MOM capacitor structure provided in the present application, a first conductive plug is connected to a first main metal line stacked vertically, and a second conductive plug located in the same layer as the first conductive plug is connected to a second main metal line stacked vertically. The present application arranges a plurality of the first conductive plugs between the first main metal lines stacked vertically and a plurality of the second conductive plugs between the second main metal lines stacked vertically, and in the same insulating dielectric layer, the first conductive plugs and the second conductive plugs are arranged in a staggered manner in a dot-like manner, so that the first conductive plug, the second conductive plug and the insulating dielectric layer therebetween constitute a plurality of MOM capacitors, thereby improving the overall capacitance density of the stacked MOM capacitor structure, improving the stability of the capacitor, and also improving the reliability of the device.

[0013] Furthermore, the preparation process of the first conductive plug and the second conductive plug of the present application is compatible with the preparation process of the metal through-hole structure in the metal interconnection process, so there is no need to add a new mask to prepare the first conductive plug and the second conductive plug, thereby improving the overall capacitance density of the stacked MOM capacitor structure without increasing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 It is the structural representation of the MOM capacitor structure of an embodiment of the present invention; Figure 2 is a schematic top view of an insulating dielectric layer where a first main metal line and a second main metal line are located in a MOM capacitor structure according to an embodiment of the present invention; Figure 3 is a schematic top view of an insulating dielectric layer where a first conductive plug and a second conductive plug are located in a MOM capacitor structure according to an embodiment of the present invention; Figure 4 yes Figure 1 A schematic cross-sectional view of the MOM capacitor structure vertically downward along the AA' direction; Figure 5 yes Figure 1 A schematic cross-sectional view of the MOM capacitor structure vertically downward along the BB' direction; Figure 6 yes Figure 1 A schematic cross-sectional view of the MOM capacitor structure vertically downward along the CC' direction; The reference numerals are described as follows: 10-insulating dielectric layer, 11-insulating dielectric layer where the first main metal wire and the second main metal wire are located, 12-insulating dielectric layer where the first conductive plug and the second conductive plug are located, 20-first main metal wire, 21-first conductive plug, 22-first end conductive plug, 30-second main metal wire, 31-second conductive plug, 32-second end conductive plug, 41-first end metal wire, 42-second end metal wire. DETAILED DESCRIPTION

[0016] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0017] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0018] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0019] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0020] The present application embodiment provides a MOM capacitor structure, referring to Figure 1 , Figure 1It is a structural schematic diagram of the MOM capacitor structure of an embodiment of the present invention, and the MOM capacitor structure includes: first to nth insulating dielectric layers 10, a plurality of first main metal wires 20, a plurality of second main metal wires 30 and a plurality of first conductive plugs 21 and a plurality of second conductive plugs 31, wherein n is an integer greater than or equal to 3.

[0021] refer to Figure 2 The first main metal wires 20 and the second main metal wires 30 are arranged in a staggered manner in a fork-shaped manner and are located in the same insulating dielectric layer 11 .

[0022] For further reference, Figure 6 , the first to nth insulating dielectric layers 10 are stacked in sequence.

[0023] Preferably, the first main metal wires 20 in the same insulating dielectric layer 11 overlap in space, and the first main metal wires 20 are all located in the insulating dielectric layer 11 of odd or even layers, which can also be understood as the first main metal wires 20 in the insulating dielectric layers 11 of each odd layer (or each even layer) are stacked in the vertical direction; similarly, the second main metal wires 30 in the same insulating dielectric layer 11 overlap in space, and the second main metal wires 30 are all located in the insulating dielectric layer 11 of odd or even layers, which can also be understood as the second main metal wires 30 in the insulating dielectric layers 11 of each odd layer (or each even layer) are stacked in the vertical direction. Specifically, refer to Figure 2 In the nth insulating dielectric layer, a plurality of the first main metal wires 20 are parallel to each other, a plurality of the second main metal wires 30 are parallel to each other, and the first main metal wires 20 and the second main metal wires 30 are arranged alternately so that the first main metal wires 20 and the second main metal wires 30 located in the same insulating dielectric layer are in a fork-shaped shape.

[0024] For further reference, Figure 3-Figure 6 , the first conductive plug 21 and the second conductive plug 31 are both located in the same insulating dielectric layer 12 .

[0025] The insulating dielectric layer 11 where the first main metal wire 20 and the second main metal wire 30 are located is alternately stacked with the insulating dielectric layer 12 where the first conductive plug 21 and the second conductive plug 31 are located.

[0026] It is worth noting that if the first main metal wire 20 and the second main metal wire 30 are both located in odd-numbered insulating dielectric layers, then the first conductive plug 21 and the second conductive plug 31 are both located in even-numbered insulating dielectric layers; if the first main metal wire 20 and the second main metal wire 30 are both located in even-numbered insulating dielectric layers, then the first conductive plug 21 and the second conductive plug 31 are both located in odd-numbered insulating dielectric layers.

[0027] like Figure 4 and Figure 6 As shown, the first conductive plug 21 and the first main metal line 20 are stacked in the longitudinal direction and the first conductive plug 21 is connected to the first main metal line 20 stacked in the longitudinal direction. Figure 5 and Figure 6 As shown, the second conductive plug 31 and the second main metal line 30 are stacked in the longitudinal direction and the second conductive plug 31 is connected to the second main metal line 30 stacked in the longitudinal direction.

[0028] Preferably, the MOM capacitor structure also includes: a first end metal wire 41 and a second end metal wire 42, the first end metal wire 41 is located in the insulating dielectric layer where the first main metal wire and the second main metal wire are located and connected to one end of the first main metal wire 20; the second end metal wire 42 is located in the insulating dielectric layer where the first main metal wire and the second main metal wire are located and connected to one end of all second main metal wires 30, one end of all second main metal wires 30 connected to the second end metal wire 42 is away from one end of all first main metal wires 20 connected to the first end metal wire 41, and it can also be understood that one end of all second main metal wires 30 connected to the second end metal wire 42 is opposite to one end of all first main metal wires 20 connected to the first end metal wire 41.

[0029] The first end metal line 41 is connected to the first main metal line 20 of the top insulating dielectric layer through the first end conductive plug 22, and further, the second end metal line 42 is connected to the second main metal line 30 of the top insulating dielectric layer through the second end conductive plug 32.

[0030] It can be seen that the first end metal line 41, the first end conductive plug 22, the first main metal line 20 and the first conductive plug 21 constitute a first metal interconnection structure; the second end metal line 42, the second end conductive plug 32, the second main metal line 30 and the second conductive plug 31 constitute a second metal interconnection structure.

[0031] refer to Figure 3In the transverse direction, the plurality of first conductive plugs 21 between the longitudinally stacked first main metal wires 20 and the plurality of second conductive plugs 31 between the longitudinally stacked second main metal wires 30 are arranged in a staggered manner in a dotted manner.

[0032] In the present application, by designing the first conductive plug 21 and the second conductive plug 31 in the same insulating dielectric layer 12 to be arranged in a staggered manner in a point-like manner, the capacitance density is improved while the reliability of the MOM capacitor is also improved. Even if the first main metal wire 20 and / or the second main metal wire 30 is broken due to high-voltage pulses or stress migration, it will have little effect on the capacitance value of the MOM capacitor structure provided in the present application.

[0033] For further reference, Figure 4 , in the longitudinal direction, the plurality of first conductive plugs 21 in the upper and lower insulating dielectric layers of any first main metal wire 20 are arranged in a staggered manner; Figure 5 In the longitudinal direction, the plurality of second conductive plugs 31 in the upper and lower insulating dielectric layers of any second main metal wire 30 are arranged in a staggered manner.

[0034] In the present application, by designing the first conductive plugs 21 in the insulating dielectric layer 12 of adjacent even-numbered layers (or odd-numbered layers) to be arranged in a staggered manner, and by designing the second conductive plugs 31 in the insulating dielectric layer 12 of adjacent even-numbered layers (or odd-numbered layers) to be arranged in a staggered manner, the stress of the insulating dielectric layer around the through hole of the conductive plug can be improved, the first main metal line and / or the second main metal line inside the device can be avoided from being disconnected or short-circuited, and the reliability of the device can be improved.

[0035] In this embodiment, the first end metal wire 41, the second end metal wire 42, the first main metal wire 20, the second main metal wire 30, the first conductive plug 21, and the second conductive plug 31 are all made of copper. In addition, the first end conductive plug 22 and the second end conductive plug 32 are also made of copper.

[0036] In this embodiment, the insulating dielectric layer 10 is made of silicon dioxide.

[0037] It is worth noting that in the insulating dielectric layer 11 where the first main metal wire and the second main metal wire are located, the line width of the first main metal wire 20 and the second main metal wire 30 and the spacing between the first main metal wire 20 and the second main metal wire 30 both comply with the minimum design rules.

[0038] In this embodiment, the first main metal line 20, the insulating dielectric layer 11 between the first main metal line 20 and the second main metal line 30 constitute a MOM capacitor; the first conductive plug 21, the second conductive plug 31 and the insulating dielectric layer 12 therebetween also constitute a plurality of MOM capacitors.

[0039] In the present application, by arranging a plurality of the first conductive plugs between the first main metal wires stacked vertically and arranging a plurality of the second conductive plugs between the second main metal wires stacked vertically, and in the same insulating dielectric layer, the first conductive plug and the second conductive plug are arranged in a staggered manner in a dotted manner, so that the first conductive plug, the second conductive plug and the insulating dielectric layer between the two constitute a plurality of MOM capacitors, thereby improving the overall capacitance density of the stacked MOM capacitor structure, improving the stability of the capacitor, and also improving the reliability of the device. Furthermore, the preparation process of the first conductive plug and the second conductive plug of the present application is compatible with the preparation process of the metal through hole structure in the metal interconnection process, so there is no need to add a new mask to prepare the first conductive plug and the second conductive plug, and the overall capacitance density of the stacked MOM capacitor structure is improved without increasing the manufacturing cost.

[0040] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection created by this application.

Claims

1. A MOM capacitor structure, characterized in that: include: First to nth insulating dielectric layers, a plurality of first main metal wires, a plurality of second main metal wires, a plurality of first conductive plugs, and a plurality of second conductive plugs, wherein n is an integer greater than or equal to 3; The first to nth insulating dielectric layers are stacked in sequence, the first main metal wire and the second main metal wire are arranged in a staggered manner in a fork-shaped manner and are located in the same insulating dielectric layer, and the first conductive plug and the second conductive plug are both located in the same insulating dielectric layer, wherein the insulating dielectric layer where the first main metal wire and the second main metal wire are located is staggered and stacked with the insulating dielectric layer where the first conductive plug and the second conductive plug are located; The first conductive plug and the first main metal line are stacked in a longitudinal direction and connected to the first main metal line stacked in a longitudinal direction, and the second conductive plug and the second main metal line are stacked in a longitudinal direction and connected to the second main metal line stacked in a longitudinal direction; The first main metal line and the first conductive plug constitute a first metal interconnect structure; the second main metal line and the second conductive plug constitute a second metal interconnect structure; In the transverse direction, the plurality of first conductive plugs between the longitudinally stacked first main metal lines and the plurality of second conductive plugs between the longitudinally stacked second main metal lines are arranged in a staggered manner in a dot-like manner.

2. MOM capacitor structure according to claim 1, is characterized in that, In the longitudinal direction, the multiple first conductive plugs in the upper and lower insulating dielectric layers of any first main metal wire are arranged alternately; the multiple second conductive plugs in the upper and lower insulating dielectric layers of any second main metal wire are arranged alternately.

3. MOM capacitor structure according to claim 1, is characterized in that, The MOM capacitor structure also includes: a first end metal wire and a second end metal wire, the first end metal wire is located in the insulating dielectric layer where the first main metal wire and the second main metal wire are located and connects the left ends of all the first main metal wires; the second end metal wire is located in the insulating dielectric layer where the first main metal wire and the second main metal wire are located and connects the right ends of all the second main metal wires.

4. MOM capacitor structure according to claim 1, is characterized in that, The first end metal line, the second end metal line, the first main metal line, the second main metal line, the first conductive plug and the second conductive plug are all made of copper.

5. MOM capacitor structure according to claim 1, is characterized in that, The insulating dielectric layer is made of silicon dioxide.

6. MOM capacitor structure according to claim 1, is characterized in that, In the insulating dielectric layer where the first main metal line and the second main metal line are located, the line widths of the first main metal line and the second main metal line and the spacing between the first main metal line and the second main metal line both meet minimum design rules.

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