Stacked spiral differential inductor structure and manufacturing method

Abstract

The invention provides a stacked spiral differential inductor structure and a preparation method thereof, and the stacked spiral differential inductor structure comprises a plurality of inductor units which are stacked to form a first stacked inductor structure and a second stacked inductor structure. A good differential structure can be realized through the first stacked inductor structure and the second stacked inductor structure, so that the stacked spiral inductor structure has good differential performance, and the inductance efficiency and the anti-interference performance of the stacked spiral differential inductor structure can be improved. In addition, due to the fact that the inductor units are arranged in a stacked mode, the stacked spiral differential inductor structure occupies a small chip area, and therefore the area utilization rate of a chip can be increased.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency device manufacturing, and in particular to a stacked spiral differential inductor structure and a manufacturing method thereof. Background Art

[0002] In RF circuits, inductors, as basic components, often play important roles such as impedance matching, filtering, and current isolation. The main parameter for measuring inductor efficiency is the quality factor Q value; the higher the Q value, the higher the efficiency of the inductor and the lower the loss.

[0003] However, increasing the Q value requires increasing the area of ​​the inductor to the maximum extent, which will reduce the area utilization of the chip.

[0004] Therefore, how to simultaneously improve the inductor efficiency and the chip area utilization rate has become a technical problem that the industry urgently needs to solve. Summary of the invention

[0005] The present invention provides a stacked spiral differential inductor structure, which solves the problem of difficulty in simultaneously improving the inductor efficiency and the area utilization rate of the chip.

[0006] According to a first aspect of the present invention, there is provided a stacked spiral differential inductor structure, comprising:

[0007] A substrate having an interlayer dielectric layer formed thereon;

[0008] A plurality of inductor units are stacked on the interlayer dielectric layer, each of the inductor units comprises a first metal layer and a second metal layer which are stacked; any one of the first metal layer and the second metal layer serves as a connection structure, and the other metal layer serves as a winding layer; the winding layer comprises a first spiral metal winding unit and a second spiral metal winding unit; at least one of the first spiral metal winding unit and the second spiral metal winding unit is a segmented metal winding segment, and adjacent metal winding segments are connected to the corresponding connection structure via a first through hole to form a continuous winding; the first spiral metal winding units in adjacent inductor units and the second spiral metal winding units in adjacent inductor units are electrically connected via connection holes to form a first stacked inductor structure and a second stacked inductor structure respectively; the connection structure and the winding layer are isolated by an intermetallic dielectric layer;

[0009] A first differential input tap and a second differential input tap are located in the winding layer of the first inductor unit, the first differential input tap and the second differential input tap are electrically connected to the first spiral metal winding unit and the second spiral metal winding unit of the first inductor unit, respectively, and are used as input terminals to input differential signals;

[0010] An output tap, located in the winding layer of the second inductor unit, the output tap is electrically connected to the first spiral metal winding unit and the second spiral metal winding unit of the second inductor unit, and is used to output a signal as an output end;

[0011] The first inductor unit is any one of the top inductor unit and the bottom inductor unit of the plurality of inductor units, and the second inductor unit is the other one of the top inductor unit and the bottom inductor unit of the plurality of inductor units.

[0012] Optionally, the first spiral metal winding unit and the second spiral metal winding unit in each winding layer together form a coil of m turns; wherein m is a natural number greater than 1.

[0013] Optionally, when m is equal to 2, any one of the first spiral metal winding unit and the second spiral metal winding unit in each winding layer is a continuous metal winding segment, and the other spiral metal winding unit includes two metal winding segments, and adjacent metal winding segments are connected to the corresponding connecting structure through a first through hole to form a continuous winding.

[0014] Optionally, when m is greater than or equal to 3, any one of the first spiral metal winding units or the second spiral metal winding units in each winding layer is a continuous metal winding segment, and the other spiral metal winding unit includes multiple metal winding segments, and adjacent metal winding segments are connected to the corresponding connecting structure through a first through hole to form a continuous winding.

[0015] Optionally, when m is greater than or equal to 3, the first spiral metal winding unit and the second spiral metal winding unit in each winding layer are both segmented metal winding segments, and adjacent metal winding segments are connected to the corresponding connecting structure through a first through hole to form a continuous winding.

[0016] Optionally, the first spiral metal winding unit and the second spiral metal winding unit in each winding layer are symmetrical with respect to a first vertical plane, wherein the first vertical plane is a vertical plane where a perpendicular bisector of a corresponding connection structure and an output tap are located.

[0017] Optionally, the difference between the length of the winding path of the first stacked inductor structure and the length of the winding path of the second stacked inductor structure is within a preset value, and the difference between the number of connection structures in the winding path of the first stacked inductor structure and the number of connection structures in the winding path of the second stacked inductor structure does not exceed 1.

[0018] Optionally, the connecting hole includes a connecting metal located in the metal layer where the connecting structure is located, a second through hole and a third through hole, wherein the second through hole is used to connect the connecting metal and the winding end point of a first spiral winding unit or a second spiral winding unit located below and adjacent to the connecting metal; the third through hole is used to connect the connecting metal and the winding starting point of the first spiral winding unit or the second spiral winding unit located above and adjacent to the connecting metal.

[0019] Optionally, the winding layer in each of the inductor units is located above the connecting structure.

[0020] According to a second aspect of the present invention, a method for manufacturing a stacked spiral differential inductor structure is provided, comprising:

[0021] Providing a substrate, on which a semiconductor device has been formed and an interlayer dielectric layer has been filled;

[0022] forming a first inductor unit, the first differential input tap and the second differential input tap or the output tap on the interlayer dielectric layer;

[0023] A metal interlayer dielectric layer is formed on the first inductor unit, and all subsequent inductor units and connection holes are prepared in sequence; and the output tap or the first differential input tap and the second differential input tap are formed in the winding layer of the last inductor unit.

[0024] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0025] In the stacked spiral differential inductor structure provided in the embodiment of the present invention, a plurality of inductor units are stacked to form a first stacked inductor structure and a second stacked inductor structure. A good differential structure can be achieved through the first stacked inductor structure and the second stacked inductor structure, so that the stacked spiral inductor structure has good differential performance, thereby improving the inductance efficiency and anti-interference performance of the stacked spiral differential inductor structure. In addition, since the inductor units are stacked, the stacked spiral differential inductor structure occupies a smaller chip area, thereby improving the area utilization rate of the chip.

[0026] Furthermore, by controlling the difference in the number of connection structures in the winding paths of the first stacked inductor structure and the second stacked inductor structure to be no more than 1, the difference in the length of the winding path of the first stacked inductor structure and the length of the winding path of the second stacked inductor structure is within a preset value, so that the stacked spiral differential inductor structure has good symmetry, further improving the anti-interference performance of the stacked spiral differential inductor structure.

[0027] Furthermore, the winding layers in each of the inductor units are located above the connecting structure, and the first metal layer serves as the connecting structure, and the second metal layer serves as the winding layer, so that the winding layer closest to the substrate is separated from the substrate by the connecting structure, thereby effectively reducing interference and parasitic capacitance of the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a view from A1 to A2 of a stacked spiral differential inductor structure including three inductor units provided by an embodiment of the present invention;

[0029] Figure 2 is a three-dimensional structural diagram of a stacked spiral differential inductor structure including three inductor units provided in one embodiment of the present invention;

[0030] Figure 3 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 1 ;

[0031] Figure 4 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 2 ;

[0032] Figure 5 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 3 ;

[0033] Figure 6 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 4 ;

[0034] Figure 7 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 5 .

[0035] Reference numerals:

[0036] 1- substrate;

[0037] 2-interlayer dielectric layer;

[0038] 3-intermetallic dielectric layer;

[0039] 4- inductor unit;

[0040] 41-a first spiral metal winding unit;

[0041] 42-a second spiral metal winding unit;

[0042] 421-Connection winding;

[0043] 43-connection structure;

[0044] 44-first through hole;

[0045] 5-Connection hole;

[0046] 51- second through hole;

[0047] 52-connecting metal;

[0048] 53-third through hole;

[0049] 6- first differential input tap;

[0050] 7- Second differential input tap;

[0051] 8-Output taps. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the embodiments in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] As described in the background art, it is difficult for the inductor in the prior art to simultaneously improve the inductor efficiency and the chip area utilization rate.

[0054] The following takes a planar spiral inductor structure and a vertical series inductor embodiment as examples to analyze in detail the problems existing in the existing inductor structure.

[0055] The planar spiral inductor structure is characterized by a gradually decreasing radius of the metal coil, which is connected through the underlying metal in the inner circle. This causes the planar inductor structure to occupy a larger substrate area when the number of turns is large, and is prone to eddy current effect and skin effect, resulting in increased losses.

[0056] The vertical series inductor structure can occupy a much smaller substrate area than the planar inductor structure under the same number of inductor turns, and the coupling coefficient between the vertical series inductor coils is also higher than that of the planar spiral inductor, so it can further reduce the inductor area under the same inductance value. However, due to the close distance between the upper and lower metal layers, the parasitic capacitance and series resistance between the metals are large, resulting in low inductor efficiency.

[0057] In view of this, the present invention creatively proposes a stacked spiral differential inductor structure.

[0058] An embodiment of the present invention provides a stacked spiral differential inductor structure, which may include:

[0059] A substrate having an interlayer dielectric layer formed thereon;

[0060] A plurality of inductor units are stacked on the interlayer dielectric layer, each of the inductor units comprises a first metal layer and a second metal layer which are stacked; any one of the first metal layer and the second metal layer serves as a connection structure, and the other metal layer serves as a winding layer; the winding layer comprises a first spiral metal winding unit and a second spiral metal winding unit; at least one of the first spiral metal winding unit and the second spiral metal winding unit is a segmented metal winding segment, and adjacent metal winding segments are connected to the corresponding connection structure via a first through hole to form a continuous winding; the first spiral metal winding units in adjacent inductor units and the second spiral metal winding units in adjacent inductor units are electrically connected via connection holes to form a first stacked inductor structure and a second stacked inductor structure respectively; the connection structure and the winding layer are isolated by an intermetallic dielectric layer;

[0061] A first differential input tap and a second differential input tap are located in the winding layer of the first inductor unit, the first differential input tap and the second differential input tap are electrically connected to the first spiral metal winding unit and the second spiral metal winding unit of the first inductor unit, respectively, and are used as input terminals to input differential signals;

[0062] An output tap, located in the winding layer of the second inductor unit, the output tap is electrically connected to the first spiral metal winding unit and the second spiral metal winding unit of the second inductor unit, and is used to output a signal as an output end;

[0063] The first inductor unit is any one of the top inductor unit and the bottom inductor unit of the plurality of inductor units, and the second inductor unit is the other one of the top inductor unit and the bottom inductor unit of the plurality of inductor units.

[0064] It can be seen that a good differential structure can be achieved through the first stacked inductor structure and the second stacked inductor structure, so that the stacked spiral inductor structure has good differential performance, thereby improving the inductance efficiency and anti-interference performance of the stacked spiral differential inductor structure. In addition, since the inductor units are stacked, the stacked spiral differential inductor structure occupies a smaller chip area, thereby improving the area utilization rate of the chip.

[0065] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0066] For ease of description, in the following embodiments, a stacked spiral differential inductor structure consisting of three inductor units is used for illustration. Those skilled in the art can understand that in other embodiments, the stacked spiral differential inductor structure described in the present application may include more inductor units.

[0067] Figure 1 is a view from A1 to A2 of a stacked spiral differential inductor structure including three inductor units provided by an embodiment of the present invention; Figure 2 is a three-dimensional structural diagram of a stacked spiral differential inductor structure including three inductor units provided in one embodiment of the present invention; Figure 3 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 1 ; Figure 4 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 2 ; Figure 5 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 3 ; Figure 6 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 4 ; Figure 7 A top view of a stacked spiral differential inductor structure provided by an embodiment of the present invention Figure 5 .

[0068] Please refer to Figure 1 as well as Figure 2 In one embodiment of the present invention, a stacked spiral differential inductor structure is provided, which may include:

[0069] A substrate 1, wherein an interlayer dielectric layer 2 is formed on the substrate 1;

[0070] Three inductance units 4 are stacked on the interlayer dielectric layer 2, each of the inductance units 4 includes a first metal layer and a second metal layer which are stacked; any one of the first metal layer and the second metal layer serves as a connection structure 43, and the other metal layer serves as a winding layer; the winding layer includes a first spiral metal winding 41 unit and a second spiral metal winding 42 unit; at least one of the first spiral metal winding 41 unit and the second spiral metal winding 42 unit is a segmented metal winding segment, and adjacent metal winding segments are connected to the corresponding connection structure 43 through a first through hole 44 to form a continuous winding; the first spiral metal winding 41 units in adjacent inductance units 4 and the second spiral metal winding 42 units in adjacent inductance units 4 are electrically connected through connection holes 5 to form a first stacked inductance structure and a second stacked inductance structure respectively; the connection structure 43 and the winding layer are isolated by the intermetallic dielectric layer 3.

[0071] In this embodiment, the stacked spiral differential inductor structure may include six metal layers, wherein the first metal layer and the second metal layer, the third metal layer and the fourth metal layer, and the fifth metal layer and the sixth metal layer respectively form three inductor units.

[0072] The two ends of the connection structure 43 are respectively connected to the connection end points of two adjacent metal winding segments through the two first through holes 44 , so that the segmented metal winding segments, the first through holes 44 and the connection structure 43 form a continuous winding.

[0073] Specifically, the first stacked inductor structure and the second stacked inductor structure each include only one winding path, so the winding end points of the first spiral metal winding 41 unit or the second spiral metal winding 42 unit in the winding layer of the previous inductor unit 4 are correspondingly connected to the winding starting points of the first spiral metal winding 41 unit or the second spiral metal winding 42 unit in the winding layer of the next inductor unit 4 through the connecting hole 5 to form the first stacked inductor structure and the second stacked inductor structure.

[0074] The difference between the length of the winding path of the first stacked inductor structure and the length of the winding path of the second stacked inductor structure is within a preset value, and the difference between the number of connection structures 43 in the winding path of the first stacked inductor structure and the number of connection structures 43 in the winding path of the second stacked inductor structure does not exceed 1. The preset value is used to represent the sum of the lengths of one connection structure and two first through holes.

[0075] For further information, please refer to Figure 3, the second spiral metal winding unit 42 is a continuous winding, the first spiral metal winding unit 41 is a segmented winding, and adjacent metal winding segments are connected to the corresponding connecting structure 43 through the first through hole to form a continuous winding. Wherein, the second spiral metal winding unit 42 includes a connecting winding 421, and the connecting winding 421 is located at the corresponding upper position of the connecting structure 43, and the preset value is further used to characterize the difference between the sum of the lengths of one connecting structure 43 and two first through holes 44 and the corresponding connecting winding 421.

[0076] Those skilled in the art can understand that segmented winding means that the spiral metal winding unit consists of at least two metal winding segments, and continuous winding means that the spiral metal winding unit has only one metal winding segment.

[0077] In this embodiment, the substrate 1 may be an SOI substrate 1, or a substrate 1 of other materials such as germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium, and the present invention does not impose any limitation on this.

[0078] Among them, the first spiral metal winding unit 41 and the second spiral metal winding unit 42 in each winding layer together form an m-turn coil. Among them, m is a natural number greater than 1. The shape of the coil includes a regular octagon, a square and a circle. Coils of different shapes will have an impact on the inductance efficiency of the stacked spiral differential inductor structure. For example: the eddy current effect at the corners of the square-shaped coil will be very obvious, and its inductance efficiency is also the lowest; the circular coil has the highest inductance efficiency, but its design is more difficult, which limits the process application; the inductance efficiency of the regular octagon is in the middle, and the process manufacturing is also relatively simple. Of course, those skilled in the art should be aware that there are many other shapes of the coil, and the present invention is not limited to this.

[0079] In a specific embodiment, please refer to Figure 4 , when m is equal to 2, there is only one connecting structure 43 in each inductor unit 4, and any one of the first spiral metal winding unit 41 and the second spiral metal winding unit 42 in each winding layer is a continuous metal winding segment, and the other spiral metal winding unit may include two metal winding segments, and the connection end points of adjacent metal winding segments are respectively connected to the two ends of the corresponding connecting structure 43 through the first through hole 44 to form a continuous winding.

[0080] In another specific embodiment, when m is greater than or equal to 3, each inductor unit 4 has (m-1) connection structures 43, and any one of the first spiral metal winding unit 41 or the second spiral metal winding unit 42 in each winding layer is a continuous metal winding segment, and the other spiral metal winding unit may include multiple metal winding segments, and the connection endpoints of adjacent metal winding segments are respectively connected to the two ends of the corresponding connection structure 43 through the first through hole 44 to form a continuous winding. For example, please refer to Figure 6 The first spiral metal winding unit 41 and the second spiral metal winding unit 42 together form a three-turn coil, and an inductor unit 4 includes two connecting structures 43. In the inductor unit 4, the first spiral metal winding unit 41 is a continuous metal winding segment, and the metal winding segments in the second spiral metal winding unit 42 are connected through two connecting structures 43 and a first through hole 44 to form a continuous winding.

[0081] In another specific embodiment, when m is greater than or equal to 3, each inductor unit 4 has (m-1) connection structures 43, and the first spiral metal winding unit 41 and the second spiral metal winding unit 42 in each winding layer are both segmented metal winding segments, and the connection ends of adjacent metal winding segments are respectively connected to the two ends of the corresponding connection structure 43 through the corresponding first through holes 44 to form a continuous winding. For example, please refer to Figure 7 The first spiral metal winding unit 41 and the second spiral metal winding unit 42 together form a three-turn coil, and an inductor unit 4 includes two connecting structures 43. In the inductor unit 4, the metal winding segments in the first spiral metal winding unit 41 and the second spiral metal winding unit 42 are connected by a connecting structure 43 and a first through hole 44 to form a continuous winding.

[0082] As a specific embodiment, the first spiral metal winding unit 41 and the second spiral metal winding unit 42 in each winding layer are symmetrical with respect to a first vertical plane, wherein the first vertical plane is a vertical plane where the perpendicular midline of the corresponding connection structure 43 and the output tap 8 are located. The symmetry of the first spiral metal winding unit 41 and the second spiral metal winding unit 42 in each winding layer with respect to the first vertical plane can reduce the parasitic capacitance of the stacked spiral differential inductor structure to the substrate 1, and has advantages such as a higher power supply voltage suppression ratio and the ability to eliminate even-order noise.

[0083] As a specific embodiment, the winding layers in each of the inductor units 4 are located above the connection structure 43, that is, the first metal layer, the third metal layer and the fifth metal layer are respectively used as the connection structures 43 in the three inductor units 4, and the second metal layer, the fourth metal layer and the sixth metal layer are respectively used as the winding layers in the three inductor units 4. Therefore, the winding layer closest to the substrate 1, that is, the second metal layer, is separated from the substrate 1 by the connection structure 43, that is, the first metal layer, thereby effectively reducing the interference and parasitic capacitance of the substrate 1.

[0084] As a specific embodiment, the connection hole 5 may include a connection metal 52, a second through hole 51 and a third through hole 53 located in the metal layer where the connection structure 43 is located, wherein the second through hole 51 is used to connect the connection metal 52 and the winding end point of the first spiral winding unit or the second spiral winding unit located below and adjacent to the connection metal 52; the third through hole 53 is used to connect the connection metal 52 and the winding start point of the first spiral winding unit or the second spiral winding unit located above and adjacent to the connection metal 52. The production of the connection hole 5 is divided into three parts: the second through hole 51, the connection metal 52 and the third through hole 53, so that the process difficulty is reduced.

[0085] As a specific embodiment, the thickness of the first metal layer and the second metal layer of each inductor unit 4 is equal, and the height of each through hole between adjacent metal layers is equal. The thickness of the metal layer may be, for example, 3200 angstroms, and the height of each through hole between the two adjacent metal layers may be, for example, 3100 angstroms. Of course, those skilled in the art can adjust the thickness of the metal layer and the height of each through hole between the two adjacent metal layers according to actual conditions, and the present invention does not limit this.

[0086] In this embodiment, please refer to Figure 2 as well as Figure 5 The first differential input tap 6 and the second differential input tap 7 are located in the winding layer of the first inductor unit. The first differential tap 6 and the second differential input tap 7 are electrically connected to the first spiral metal winding unit 41 and the second spiral metal winding unit 42 of the first inductor unit respectively, and are used as input terminals to input differential signals.

[0087] In this embodiment, please refer to Figure 2 as well as Figure 3 The output tap 8 is located in the winding layer of the second inductor unit. The output tap 8 is electrically connected to the first spiral metal winding unit 41 and the second spiral metal winding unit 42 of the second inductor unit and is used as an output end to output signals.

[0088] The first inductor unit is any one of the top inductor unit and the bottom inductor unit of the plurality of inductor units, and the second inductor unit is the other one of the top inductor unit and the bottom inductor unit of the plurality of inductor units.

[0089] Specifically, the first end of the first differential input tap 6 is electrically connected to the winding start point of the first spiral metal winding unit 41 of the bottom inductor unit, or the winding end point of the first spiral metal winding unit 41 of the top inductor unit; the first end of the second differential input tap 7 is electrically connected to the winding start point of the second spiral metal winding unit 42 of the bottom inductor unit, or the winding end point of the second spiral metal winding unit 42 of the top inductor unit; the second end of the first differential input tap 6 and the second end of the second differential input tap 7 are used as input ends to input differential signals. The first differential input tap 6 and the second differential input tap 7 are symmetrical about the first vertical plane.

[0090] Specifically, the first end of the output tap 8 is electrically connected to the winding end point of the first spiral metal winding unit 41 of the top-level inductance unit and the winding end point of the corresponding second spiral metal winding unit 42; or, the first end of the output tap 8 is electrically connected to the winding starting point of the first spiral metal winding unit 41 of the bottom-level inductance unit 4 and the winding starting point of the corresponding second spiral metal winding unit 42; the second end of the output tap 8 is used as an output end to output a signal.

[0091] In summary, the stacked spiral differential inductor structure provided in the embodiment of the present invention includes a plurality of inductor units stacked to form a first stacked inductor structure and a second stacked inductor structure. A good differential structure can be achieved through the first stacked inductor structure and the second stacked inductor structure, so that the stacked spiral inductor structure has good differential performance, thereby improving the inductance efficiency and anti-interference performance of the stacked spiral differential inductor structure. In addition, since the inductor units are stacked, the stacked spiral differential inductor structure occupies a smaller chip area, thereby improving the area utilization rate of the chip.

[0092] Furthermore, by controlling the difference in the number of connection structures in the winding paths of the first stacked inductor structure and the second stacked inductor structure to be no more than 1, the difference in the length of the winding path of the first stacked inductor structure and the length of the winding path of the second stacked inductor structure is within a preset value, so that the stacked spiral differential inductor structure has good symmetry, further improving the anti-interference performance of the stacked spiral differential inductor structure.

[0093] Furthermore, the winding layers in each of the inductor units are located above the connecting structure, and the first metal layer serves as the connecting structure, and the second metal layer serves as the winding layer, so that the winding layer closest to the substrate is separated from the substrate by the connecting structure, thereby effectively reducing interference and parasitic capacitance of the substrate.

[0094] Please refer to Figures 1 to 5 The present invention also provides a method for manufacturing a stacked spiral differential inductor structure, which may include:

[0095] S1: providing a substrate 1 on which a semiconductor device has been formed and an interlayer dielectric layer 2 has been filled.

[0096] S2: Please refer to Figure 2 , and combined with Figure 3 or Figure 5 , a bottom layer inductor unit, the first differential input tap 6 and the second differential input tap 7 or the output tap 8 are formed on the interlayer dielectric layer 2.

[0097] In this embodiment, S2 specifically includes:

[0098] S21 : forming a first intermetallic dielectric layer 3 on the interlayer dielectric layer 2 .

[0099] S22 : forming at least one lower connection structure 43 in the first intermetallic dielectric layer 3 .

[0100] S23 : forming a second intermetallic dielectric layer 3 on the first intermetallic dielectric layer 3 , wherein the second intermetallic dielectric layer 3 covers the connection structure 43 .

[0101] S24: at least two first through holes 44, a first spiral metal winding unit 41, a second spiral metal winding unit 42 and the first differential input tap 6 and the second differential input tap 7 or the output tap 8 are formed in the second intermetallic dielectric layer 3 to form a bottom layer inductor unit.

[0102] Among them, S22 specifically includes:

[0103] S221: forming a patterned first mask layer on the first intermetallic dielectric layer 3, wherein the patterned first mask layer includes at least one connection structure 43 pattern.

[0104] S222 : using the patterned first mask layer as a mask, etching the first intermetallic dielectric layer 3 to form a connection structure 43 pattern in the first intermetallic dielectric layer 3 .

[0105] S223 : depositing a metal material in the pattern of the connection structure 43 to form a first metal layer serving as the connection structure 43 .

[0106] The material of the first mask layer may be photoresist. Of course, there are many other materials for the first mask layer, and the present invention does not limit this.

[0107] Among them, the specific steps in S24 are similar to the process steps of S221 to S223, so they are not repeated here.

[0108] The metal material may include, for example, tantalum, tantalum nitride and copper. Of course, there are many other types of metal materials, which are not limited in the present invention.

[0109] S3: Please refer to Figure 1 as well as Figure 2 , forming an intermetallic dielectric layer 3 on the bottom inductor unit, and completing the preparation of all subsequent inductor units 4 and connecting holes 5 in sequence; and forming the output tap 8 or the first differential input tap 6 and the second differential input tap 7 in the winding layer of the top inductor unit.

[0110] As a specific implementation, please refer to Figure 2 as well as Figure 4 In step S3, the kth inductor unit 4 (k is a positive integer greater than 1 and k is less than N, where N is used to represent the number of inductor units) and the connection hole 5 are prepared, which specifically includes:

[0111] S31 : forming a (4k-5)th intermetallic dielectric layer 3 on the (4k-6)th intermetallic dielectric layer 3 , wherein the third intermetallic dielectric layer 3 covers the (k-1)th inductor unit 4 .

[0112] S32: forming two second through holes 51 in the (4k-5)th intermetallic dielectric layer 3.

[0113] S33 : forming a (4k-4)th intermetallic dielectric layer 3 on the (4k-5)th intermetallic dielectric layer 3 , wherein the (4k-4)th intermetallic dielectric layer 3 covers the two second through holes 51 .

[0114] S34: forming at least one connection structure 43 and two connection metals 52 in the (4k-4)th intermetallic dielectric layer 3 .

[0115] S35 : forming a (4k-3)th intermetallic dielectric layer 3 on the (4k-4)th intermetallic dielectric layer 3 , wherein the (4k-3)th intermetallic dielectric layer 3 covers the at least one connection structure 43 and the two connection metals 52 .

[0116] S36: at least two first through holes 44, two third through holes 53, a first spiral metal winding unit 41 and a second spiral metal winding unit 42 are formed in the (4k-3)th intermetallic dielectric layer 3 to constitute the kth inductor unit 4 and the connecting hole 5.

[0117] Among them, please refer to Figure 2 , and combined with Figure 3 or Figure 5 , when k=N, preparation is performed according to S31~S35, and finally at least two first through holes 44, two third through holes 53, a first spiral metal winding unit 41, a second spiral metal winding unit 42 and the output tap 8 or the first differential input tap 6 and the second differential input tap 7 are formed in the (4k-3)th intermetallic dielectric layer 3 to form the Nth inductor unit 4 and the connecting hole 5.

[0118] Among them, the specific steps in S32, S34, and S36 are similar to the process steps of S221 to S223, so they are not repeated here.

[0119] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A stacked spiral differential inductor structure, characterized in that: include: A substrate having an interlayer dielectric layer formed thereon; A plurality of inductor units are stacked on the interlayer dielectric layer, each of the inductor units comprises a first metal layer and a second metal layer which are stacked; any one of the first metal layer and the second metal layer serves as a connection structure, and the other metal layer serves as a winding layer; the winding layer comprises a first spiral metal winding unit and a second spiral metal winding unit; at least one of the first spiral metal winding unit and the second spiral metal winding unit is a segmented metal winding segment, and adjacent metal winding segments are connected to the corresponding connection structure through a first through hole to form a continuous winding; the first spiral metal winding units in adjacent inductor units and the second spiral metal winding units in adjacent inductor units are electrically connected through connection holes to form a first stacked inductor structure and a second stacked inductor structure respectively; the connection structure and the winding layer are isolated by an intermetallic dielectric layer; A first differential input tap and a second differential input tap are located in the winding layer of the first inductor unit, the first differential input tap and the second differential input tap are electrically connected to the first spiral metal winding unit and the second spiral metal winding unit of the first inductor unit, respectively, and are used as input terminals to input differential signals; An output tap, located in the winding layer of the second inductor unit, the output tap is electrically connected to the first spiral metal winding unit and the second spiral metal winding unit of the second inductor unit, and is used to output a signal as an output end; The first inductor unit is any one of the top inductor unit and the bottom inductor unit of the plurality of inductor units, and the second inductor unit is the other one of the top inductor unit and the bottom inductor unit of the plurality of inductor units.

2. The stacked spiral differential inductor structure according to claim 1, characterized in that: The first spiral metal winding unit and the second spiral metal winding unit in each of the winding layers together form a coil of m turns; wherein m is a natural number greater than 1.

3. The stacked spiral differential inductor structure according to claim 2, characterized in that: When m is equal to 2, any one of the first spiral metal winding unit and the second spiral metal winding unit in each winding layer is a continuous metal winding segment, and the other spiral metal winding unit includes two metal winding segments, and adjacent metal winding segments are connected to the corresponding connecting structure through a first through hole to form a continuous winding.

4. The stacked spiral differential inductor structure according to claim 2, characterized in that: When m is greater than or equal to 3, any one of the first spiral metal winding units or the second spiral metal winding units in each winding layer is a continuous metal winding segment, and the other spiral metal winding unit includes multiple metal winding segments, and adjacent metal winding segments are connected to the corresponding connecting structure through a first through hole to form a continuous winding.

5. The stacked spiral differential inductor structure according to claim 2, characterized in that: When m is greater than or equal to 3, the first spiral metal winding unit and the second spiral metal winding unit in each winding layer are both segmented metal winding segments, and adjacent metal winding segments are connected to the corresponding connection structure through a first through hole to form a continuous winding.

6. The stacked spiral differential inductor structure according to any one of claims 2 to 5, characterized in that: The first spiral metal winding unit and the second spiral metal winding unit in each winding layer are symmetrical with respect to a first vertical plane, wherein the first vertical plane is a vertical plane where the midline of the corresponding connection structure and the output tap are located.

7. The stacked spiral differential inductor structure according to claim 1, characterized in that: A difference between a length of a winding path of the first stacked inductor structure and a length of a winding path of the second stacked inductor structure is within a preset value, and a difference between a number of connection structures in the winding path of the first stacked inductor structure and a number of connection structures in the winding path of the second stacked inductor structure does not exceed 1; wherein the preset value is used to characterize the sum of the lengths of one of the connection structures and the two first through holes.

8. The stacked spiral differential inductor structure according to claim 1 or 7, characterized in that: The connecting hole includes a connecting metal located in the metal layer where the connecting structure is located, a second through hole and a third through hole, wherein the second through hole is used to connect the connecting metal and the winding end point of a first spiral winding unit or a second spiral winding unit located below and adjacent to the connecting metal; the third through hole is used to connect the connecting metal and the winding starting point of a first spiral winding unit or a second spiral winding unit located above and adjacent to the connecting metal.

9. The stacked spiral differential inductor structure according to claim 1, characterized in that: The winding layer in each of the inductor units is located above the connecting structure.

10. A method for manufacturing a stacked spiral differential inductor structure, characterized in that: For manufacturing the stacked spiral differential inductor structure according to any one of claims 1 to 9, the method comprises: Providing a substrate, on which an interlayer dielectric layer is formed; forming a bottom layer inductor unit, the first differential input tap and the second differential input tap or the output tap on the interlayer dielectric layer; A metal interlayer dielectric layer is formed on the bottom layer inductor unit, and all subsequent inductor units and connection holes are prepared in sequence; and the output tap or the first differential input tap and the second differential input tap are formed in the winding layer of the top layer inductor unit.

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