Patent Publication Number: US-2023154670-A1

Title: Inductor device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Taiwan Application Serial Number 110142759, filed Nov. 17, 2021, which is herein incorporated by reference in its entirety. 
     BACKGROUND 
     Field of Invention 
     This disclosure relates to an electronic device, and in particular to an inductor device. 
     Description of Related Art 
     Various types of existing inductors have their own advantages and disadvantages. For a symmetrical differential inductor, its parasitic capacitance is large, which results in a low self-resonance frequency and a low quality factor. Therefore, the application range of the aforementioned inductor is limited. 
     SUMMARY 
     An aspect of present disclosure relates to an inductor device. The inductor device includes a first winding in a first metal layer, a second winding in a second metal layer, a first connecting structure and a second connecting structure. The first winding includes a first coil and a second coil. The second winding includes a third coil and a fourth coil, the third coil is overlapped with the first coil in a direction perpendicular to the first coil, and the fourth coil is overlapped with the second coil in a direction perpendicular to the second coil. The first connecting structure includes a first crossing structure and a second crossing structure. The first crossing structure has a first crossing point and is configured to couple the first coil and the second coil. The second crossing structure has a second crossing point and is configured to couple the third coil and the fourth coil. The first crossing point is not overlapped with the second crossing point. The second connecting structure is configured to couple the second coil and the third coil. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an inductor device in accordance with some embodiments of the present disclosure; 
         FIG.  2 A  is a schematic diagram of partial structure of the inductor device of  FIG.  1    in accordance with some embodiments of the present disclosure; 
         FIG.  2 B  is a schematic diagram of partial structure of the inductor device of  FIG.  1    in accordance with some embodiments of the present disclosure; 
         FIG.  3    is a schematic diagram of a cross-section of the inductor device along a virtual line A-A in  FIG.  1    in accordance with some embodiments of the present disclosure; 
         FIG.  4    is a schematic diagram of partial structure of a first connecting structure in accordance with some embodiments of the present disclosure; 
         FIG.  5    is a schematic diagram of partial structure of a second connecting structure in accordance with some embodiments of the present disclosure; and 
         FIG.  6    is a schematic diagram of experimental data of the inductor device in accordance with some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments are described in detail below with reference to the appended drawings to better understand the aspects of the present disclosure. However, the provided embodiments are not intended to limit the scope of the disclosure, and the description of the structural operation is not intended to limit the order in which they are performed. Any device that has been recombined by components and produces an equivalent function is within the scope covered by the disclosure. 
     The terms used in the entire specification and the scope of the patent application, unless otherwise specified, generally have the ordinary meaning of each term used in the field, the content disclosed herein, and the particular content. 
     The terms “coupled” or “connected” as used herein may mean that two or more elements are directly in physical or electrical contact, or are indirectly in physical or electrical contact with each other. It can also mean that two or more elements interact with each other. 
     Referring to  FIG.  1   ,  FIG.  1    a schematic diagram of an inductor device  100  in accordance with some embodiments of the present disclosure. The inductor device  100  includes a first winding C 1 , a second winding C 2 , a first connecting structure CN 1 , a second connecting structure CN 2  and an input-output terminal IOE. In some embodiments, the first winding C 1  and the second winding C 2  are overlapped with each other via a configuration of the first connecting structure CN 1  and the second connecting structure CN 2 . It can be appreciated that the terms “overlapped” as used herein refer to substantial overlapping or actual overlapping. 
     In particular, the second connecting structure CN 2  and the input-output terminal IOE are on a first side S 1  of the inductor device  100 , and the first connecting structure CN 1  is on a second side S 2  of the inductor device  100 . As shown in  FIG.  1   , the first side S 1  (e.g., a lower side) and the second side S 2  (e.g., an upper side) are two opposite sides. 
     For easily understanding, the structure of the inductor device  100  would be described in following paragraphs with reference to  FIGS.  2 A and  2 B . Referring to  FIGS.  2 A and  2 B ,  FIG.  2 A  is a schematic diagram of a structure of the inductor device  100  in a first metal layer in accordance with some embodiments of the present disclosure, and  FIG.  2 B  is a schematic diagram of a structure of the inductor device  100  in a second metal layer in accordance with some embodiments of the present disclosure. In some embodiments, the first metal layer is a lower layer, the second metal layer is an upper layer, but the present disclosure is not limited herein. 
     It can be appreciated that the structure of the inductor device  100  in the first metal layer is represented as inclined line grids in  FIGS.  1  and  2 A , and the structure of the inductor device  100  in the second metal layer is represented as dot grids in  FIGS.  1  and  2 B . 
     As shown in  FIG.  2 A , the first winding C 1  is in the first metal layer, and the first winding C 1  is configured with a plurality of coils FC 1 -FC 4  from outside to inside. The coil FC 1  includes a half coil DP 1  and a half coil DP 2 , and the half coil DP 1  and the half coil DP 2  are symmetrically configured in the first metal layer to substantially present a square. In particular, the half coil DP 1  is on a third side S 3  of the inductor device  100 , and the half coil DP 2  is on a fourth side S 4  of the inductor device  100 . The third side S 3  (e.g., a left side) and the fourth side S 4  (e.g., a right side) are two opposite sides. The structures of other coils FC 2 -FC 4  can be deduced by analogy, and therefore the descriptions thereof are omitted herein. 
     As shown in  FIG.  2 B , the second winding C 2  is in the second metal layer different from the first metal layer, and the second winding C 2  is also configured with a plurality of coils SC 1 -SC 4  from outside to inside. The coil SC 1  includes a half coil UP 1  and a half coil UP 2 , and the half coil UP 1  and the half coil UP 2  are symmetrically configured in the second metal layer to substantially present a square. In particular, the half coil UP 1  is on the third side S 3  of the inductor device  100  and is overlapped with the half coil DP 1  in a direction perpendicular to the half coil DP 1 . The half coil UP 2  is on the fourth side S 4  of the inductor device  100  and is overlapped with the half coil DP 2  in a direction perpendicular to the half coil DP 2 . In other words, the coil SC 1  of the second winding C 2  is overlapped with the coil FC 1  of the first winding C 1  in a direction perpendicular to the coil FC 1  of the first winding C 1 . The structures of other coils SC 2 -SC 4  can be deduced by analogy, and therefore the descriptions thereof are omitted herein. 
     As shown in  FIGS.  2 A and  2 B , the first connecting structure CN 1  includes a plurality of connecting members  101 ,  103 ,  105  and  107  which are in the first metal layer and a plurality of connecting members  102 ,  104 ,  106  and  108  which are in the second metal layer. The second connecting structure CN 2  includes a plurality of connecting members  201 ,  203  and  205  which are in the first metal layer and a plurality of connecting members  202 ,  204 ,  206  and  207  which are in the second metal layer. 
     In detail, the half coil DP 2  of the first winding C 1  is directly coupled to the input-output terminal IOE on the first side S 1  and is coupled to one terminal of the connecting member  102  through a via on the second side S 2 . The other terminal of the connecting member  102  is coupled to the half coil DP 3  of the first winding C 1  through a via. That is, the half coil DP 2  in the first metal layer is coupled to the half coil DP 3  in the first metal layer through the connecting member  102  in the second metal layer. 
     The half coil DP 3  is coupled to one terminal of the connecting member  202  through a via on the first side S 1 . The other terminal of the connecting member  202  is directly coupled to the half coil UP 2  of the second winding C 2 . That is, the half coil DP 3  in the first metal layer is coupled to the half coil UP 2  in the second metal layer through the connecting member  202  in the second metal layer. 
     The half coil UP 2  is directly coupled to one terminal of the connecting member  104  on the second side S 2 . The other terminal of the connecting member  104  is directly coupled to the half coil UP 3  of the second winding C 2 . That is, the half coil UP 2  in the second metal layer is coupled to the half coil UP 3  in the second metal layer through the connecting member  104  in the second metal layer. 
     The half coil UP 3  is coupled to one terminal of the connecting member  203  through a via on the first side S 1 . The other terminal of the connecting member  203  is directly coupled to the half coil DP 6  of the first winding C 1 . That is, the half coil UP 3  in the second metal layer is coupled to the half coil DP 6  in the first metal layer through the connecting member  203  in the first metal layer. 
     The half coil DP 6  is coupled to one terminal of the connecting member  106  through a via on the second side S 2 . The other terminal of the connecting member  106  is coupled to the half coil DP 7  of the first winding C 1  through a via. That is, the half coil DP 6  in the first metal layer is coupled to the half coil DP 7  in the first metal layer through the connecting member  106  in the second metal layer. 
     The half coil DP 7  is coupled to one terminal of the connecting member  206  through a via on the first side S 1 . The other terminal of the connecting member  206  is directly coupled to the half coil UP 6  of the second winding C 2 . That is, the half coil DP 7  in the first metal layer is coupled to the half coil UP 6  in the second metal layer through the connecting member  206  in the second metal layer. 
     The half coil UP 6  is directly coupled to one terminal of the connecting member  108  on the second side S 2 . The other terminal of the connecting member  108  is directly coupled to the half coil UP 7  of the second winding C 2 . That is, the half coil UP 6  in the second metal layer is coupled to the half coil UP 7  in the second metal layer through the connecting member  108  in the second metal layer. 
     The half coil UP 7  is directly coupled to one terminal of the connecting member  207  on the first side S 1 . The other terminal of the connecting member  207  is directly coupled to the half coil UP 8  of the second winding C 2 . That is, the half coil UP 7  in the second metal layer is coupled to the half coil UP 8  in the second metal layer through the connecting member  207  in the second metal layer. In some embodiments, a central tap terminal (not shown) can be configured on the connecting member  207 . 
     The half coil UP 8  is coupled to one terminal of the connecting member  107  through a via on the second side S 2 . The other terminal of the connecting member  107  is coupled to the half coil UP 5  of the second winding C 2  through a via. That is, the half coil UP 8  in the second metal layer is coupled to the half coil UP 5  in the second metal layer through the connecting member  107  in the first metal layer. 
     The half coil UP 5  is coupled to one terminal of the connecting member  205  through a via on the first side S 1 . The other terminal of the connecting member  205  is directly coupled to the half coil DP 8  of the first winding C 1 . That is, the half coil UP 5  in the second metal layer is coupled to the half coil DP 8  in the first metal layer through the connecting member  205  in the first metal layer. 
     The half coil DP 8  is directly coupled to one terminal of the connecting member  105  on the second side S 2 . The other terminal of the connecting member  105  is directly coupled to the half coil DP 5  of the first winding C 1 . That is, the half coil DP 8  in the first metal layer is coupled to the half coil DP 5  in the first metal layer through the connecting member  105  in the first metal layer. 
     The half coil DP 5  is coupled to one terminal of the connecting member  204  through a via on the first side S 1 . The other terminal of the connecting member  204  is directly coupled to the half coil UP 4  of the second winding C 2 . That is, the half coil DP 5  in the first metal layer is coupled to the half coil UP 4  in the second metal layer through the connecting member  204  in the second metal layer. 
     The half coil UP 4  is coupled to one terminal of the connecting member  103  through a via on the second side S 2 . The other terminal of the connecting member  103  is coupled to the half coil UP 1  of the second winding C 2  through a via. That is, the half coil UP 4  in the second metal layer is coupled to the half coil UP 1  in the second metal layer through the connecting member  103  in the first metal layer. 
     The half coil UP 1  is coupled to one terminal of the connecting member  201  through a via on the first side S 1 . The other terminal of the connecting member  201  is directly coupled to the half coil DP 4  of the first winding C 1 . That is, the half coil UP 1  in the second metal layer is coupled to the half coil DP 4  in the first metal layer through the connecting member  201  in the first metal layer. 
     The half coil DP 4  is directly coupled to one terminal of the connecting member  101  on the second side S 2 . The other terminal of the connecting member  101  is directly coupled to the half coil DP 1  of the first winding C 1 . That is, the half coil DP 4  in the first metal layer is coupled to the half coil DP 1  in the first metal layer through the connecting member  101  in the first metal layer. In addition, the half coil DP 1  is directly coupled to the input-output terminal IOE on the first side S 1 . 
     It can be seen from above descriptions that the first connecting structure CN 1  is configured to couple the coils in the same metal layer, and that the second connecting structure CN 2  is configured to couple the coils in the different layers. 
     In some embodiments, the input-output terminal IOE is configured to input or output signal. It can be seen from the structure of the inductor device  100  that two half coils overlapped with each other can transmit signals with same polarity (e.g., same positive polarity signals or same negative polarity signals). For example, the signal transmitted by the half coil DP 1  of the first winding C 1  and the signal transmitted by the half coil UP 1  of the second winding C 2  have same polarity. The arrangements of other half coils DP 2 -DP 8  and UP 2 -UP 8  can be deduced by analogy, and therefore the descriptions thereof are omitted herein. 
     Two half coils which are on the same side and are separated by one half coil can transmit signals with same polarity (e.g., same positive polarity signals or same negative polarity signals), and two adjacent half coils which are on the same side can transmit signals with different polarities (e.g., one is positive polarity signal, and another one is negative polarity signal). For example, the signal transmitted by the half coil DP 1  of the first winding C 1  has same polarity as the signal transmitted by the half coil DP 5  of the first winding C 1 , but has different polarity from the signal transmitted by the half coil DP 3  of the first winding C 1 . The arrangements of other half coils DP 2 , DP 4 , DP 6 -DP 8  and UP 1 -UP 8  can be deduced by analogy, and therefore the descriptions thereof are omitted herein. 
     It can be further appreciated that two half coils of the same coil can transmit signals with different polarities (e.g., one is positive polarity signal, and another one is negative polarity signal). For example, the signal transmitted by the half coil DP 1  of the first winding C 1  has different polarity from the signal transmitted by the half coil DP 2  of the first winding C 1 . The arrangements of other half coils DP 3 -DP 8  and UP 1 -UP 8  can be deduced by analogy, and therefore the descriptions thereof are omitted herein. 
     Accordingly, in the embodiments of  FIGS.  2 A and  2 B , the half coils DP 2 , DP 3 , UP 2 , UP 3 , DP 6 , DP 7 , UP 6  and UP 7  are configured to transmit a first polarity signal (not shown), and the half coils DP 1 , DP 4 , UP 1 , UP 4 , DP 5 , DP 8 , UP 5  and UP 8  are configured to transmit a second polarity signal (not shown) different from the first polarity signal. For convenience of understanding, the transmission of first polarity signal and the second polarity signal in the inductor device  100  would be described in following paragraphs with reference to  FIG.  3   . 
     Referring to  FIG.  3   ,  FIG.  3    is a schematic diagram of a cross-section of the inductor device  100  along a virtual line A-A in  FIG.  1    in accordance with some embodiments of the present disclosure. In the embodiment of  FIG.  3   , the first polarity signal transmitted in the half coils DP 2 , DP 3 , UP 2 , UP 3 , DP 6 , DP 7 , UP 6  and UP 7  is a negative polarity signal, and the second polarity signal transmitted in the half coils DP 1 , DP 4 , UP 1 , UP 4 , DP 5 , DP 8 , UP 5  and UP 8  is a positive polarity signal. It can be seen from the distribution of polarity as shown in  FIG.  3    that the parasitic capacitors Cp are mostly formed between two adjacent half coils in the same layer (e.g., the half coil DP 1  and the half coil DP 3 ). It can be appreciated that the number and the position of the parasitic capacitors Cp are not limited to those of  FIG.  3   . For example, the parasitic capacitor might be formed between the half coil DP 1  and the half coil UP 3  which are in the different layers, however, the capacitance thereof might be much smaller than the capacitance of the parasitic capacitor Cp between the half coil DP 1  and the half coil DP 3 . Since the distance between the half coils (e.g., the half coil DP 1  and the half coil DP 3 ) which are responsible for transmitting signals with different polarities in the inductor device  100  is increased, the capacitance of each parasitic capacitor Cp is reduced, so that the equivalent parasitic capacitance of the inductor device  100  can be reduced dramatically. In some embodiments, the equivalent parasitic capacitance of the inductor device  100  is 125 fF, which is reduced by 83% in comparison to the prior art. 
     Referring to  FIG.  4   ,  FIG.  4    is a schematic diagram of partial structure of the first connecting structure CN 1  in accordance with some embodiments of the present disclosure. The symbol of  FIG.  4    which is same as those of  FIG.  1 ,  2 A or  2 B  represents same or similar component, and therefore the description thereof is omitted herein. In the first connecting structure CN 1 , the connecting member  101  in the first metal layer is intersected with the connecting member  102  in the second metal layer to constitute a first crossing structure. The connecting member  103  in the first metal layer is intersected with the connecting member  104  in the second metal layer to constitute a second crossing structure. As shown in  FIG.  4   , the first crossing structure has a first crossing point CP 1 , the second crossing structure has a second crossing point CP 2 , and the first crossing point CP 1  and the second crossing point CP 2  are not overlapped. In other words, the first crossing structure and the second crossing structure are not overlapped. 
     Notably, by the first crossing structure and the second crossing structure which are not overlapped, the couple of the coils FC 1  and FC 2  and the couple of the coils SC 1  and SC 2  can be implemented without a connecting member in a third layer (which is different from the first and the second layers). 
     As shown in  FIG.  4    again, the connecting member  103  in the first metal layer is intersected with the connecting member  102  in the second metal layer, and is not overlapped with the connecting member  101  in the first metal layer. In addition, the connecting member  104  in the second metal layer is intersected with the connecting member  101  in the first metal layer, and is not overlapped with the connecting member  102  in the second metal layer. 
     Referring to  FIG.  5   ,  FIG.  5    is a schematic diagram of partial structure of the second connecting structure CN 2  in accordance with some embodiments of the present disclosure. In the second connecting structure CN 2 , the connecting member  201  is intersected with the connecting member  202 , the connecting member  203  is intersected with the connecting member  204 , the connecting member  205  is intersected with the connecting member  206 , and the connecting member  207  is not overlapped with the connecting members  201 - 206 . 
     In some embodiments, the first metal layer is an ultra-thick metal (UTM) layer, the second metal layer is aluminum redistribution layer (AL-RDL), and the thickness of the second metal layer is smaller than the thickness of the first metal layer. It can be appreciated that the present disclosure is not limited herein. 
     In the aforementioned embodiments, the inductor  100  has a square structure (i.e., a quadrilateral structure). It can be appreciated that the inductor device can also be other polygonal structure in other embodiments. In addition, it can be appreciated that the number of the coils of the first winding C 1  and the number of the coils of the second winding C 2  are only for example, and the present disclosure is not limited to the number as shown in the drawings. 
     Referring to  FIG.  6   ,  FIG.  6    is a schematic diagram of experimental data of the inductor device  100  in accordance with some embodiments of the present disclosure. As shown in  FIG.  6   , by adopting the structural configuration of the present disclosure, the experimental curve of the quality factor of the inductor device is Q, and the experimental curve of the inductance value of the inductor device is L. In comparison to the prior art, the inductor device  100  adopting the structure of the present disclosure has better quality factor and inductance value. For example, the quality factor (Q) of the inductor device  100  is about 10.97 at the working frequency 2 GHz, which is increased by 5% in comparison to the prior art. In addition, the self-resonance frequency (Fsr) of the inductor device  100  is about 4.9 GHz, which is increased by 88% in comparison to the prior art. Since the working frequency of 2 GHz of the inductor device  100  is away from the self-resonance frequency of 4.9 GHz of the inductor device  100 , the inductance value of the inductor device  100  is more stable at the working frequency of 2 GHz (that is, the inductance value of the inductor device  100  changes less obviously in the range centered at the working frequency of 2 GHz). 
     It can be seen from the above embodiments of the present disclosure that the inductor device  100  of the present disclosure has the advantage of reduced equivalent parasitic capacitance by stacked structure (that is, the first winding C 1  and the second winding C 2  are substantially overlapped with each other). In addition, the inductor device  100  can further increase the self-resonance frequency and the quality factor by the structure of the present disclosure. 
     Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.