Patent Publication Number: US-9406740-B2

Title: Silicon process compatible trench magnetic device

Description:
DOMESTIC PRIORITY 
     This application claims priority to U.S. application Ser. No. 14/200,503, filed Mar. 7, 2014, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The present invention relates generally to semiconductor integrated magnetic devices, and more specifically, to a toroidal trench inductor. 
     When constructing a semiconductor integrated magnetic device using a magnetic film, it is desirable to make the magnetic film sufficiently thick to obtain desirable operating characteristics for a given frequency of operation. However, the thickness of a single magnetic layer that is required for a given operating frequency of the magnetic device may result in the build-up of eddy currents in the magnetic material during operation, thereby resulting in some loss. As such, the magnetic film is typically made sufficiently thin to avoid eddy current losses, but with the tradeoff of lower energy storage ability. 
     The energy storage of an integrated magnetic device can be increased, however, by building a magnetic structure using a stack of alternating thin magnetic and insulating films, wherein the magnetic layers are separated by a thin insulating layer. In general, the use of multiple layers of magnetic material separated by layers of insulating material serves to prevent the build-up of eddy currents in the magnetic material, while providing an effective thickness of magnetic material, which is sufficient to obtain the desired operating characteristics for a given frequency of operation. 
     Conventional techniques for building multilayer magnetic-insulator structures include sputtering techniques. In general, a sputtering process includes forming a multilayer stack by alternately sputtering layers of a magnetic material and a dielectric material, patterning a photoresist layer to form an etch mask, using the etch mask to etch the multilayer stack of magnetic-insulating layers and remove unwanted regions of the multilayer stack, and then removing the etch mask. While sputtering can be used to build stacks of magnetic-insulating layers, the material and manufacturing costs for sputtering are high. 
     BRIEF SUMMARY 
     According to an exemplary embodiment, a method of integrating an inductor into a semiconductor is provided. The method includes providing a circular or other closed loop trench in a substrate, in which the trench is formed with sidewalls connected by a bottom surface in the substrate. The method includes depositing a first insulator layer on the sidewalls of the trench so as to coat the sidewalls and the bottom surface, and depositing a conductor layer on the sidewalls and the bottom surface of the trench so as to coat the first insulator layer in the trench such that the conductor layer is on top of the first insulator layer in the trench. A first magnetic layer is deposited on the sidewalls and the bottom surface of the trench so as to coat the first insulator layer in the trench without filling the trench. The first magnetic layer deposited on the sidewalls forms an inner closed magnetic loop and an outer closed magnetic loop within the trench. An interior conductor path is formed by the conductor layer at an inside wall of the trench, such that the interior conductor path connects to a first exterior conductor connection. A second exterior conductor connection separately connects to the conductor layer formed on an outside wall of the trench. An electrical path from the first exterior conductor connection to the second exterior connection by way of the conductor layer in the trench forms a continuous electrical path that passes through the inner and outer closed magnetic loops. 
     According to another exemplary embodiment, an integrated inductor in a semiconductor is provided. The integrated inductor includes a circular or other closed loop trench in a substrate, in which the trench is formed with sidewalls connected by a bottom surface in the substrate. A first insulator layer is deposited on the sidewalls of the trench so as to coat the sidewalls and the bottom surface. A conductor layer is deposited on the sidewalls and bottom surface of the trench so as to coat the first insulator layer in the trench such that the conductor layer is on top of the first insulator layer in the trench. A second insulator layer is deposited on top of the conductor layer on the sidewalls and the bottom surface of the trench. A first magnetic layer is deposited on the sidewalls and the bottom surface of the trench so as to coat the second insulator layer in the trench without filling the trench. The first magnetic layer deposited on the sidewalls forms an inner closed magnetic loop and an outer closed magnetic loop within the trench. An interior conductor path is formed by the conductor layer at an inside wall of the trench, such that the interior conductor path connects to a first exterior conductor connection. A second exterior conductor connection separately connects to the conductor layer formed on an outside wall of the trench. An electrical path from the first exterior connection to the second exterior connection by way of the conductor layer in the trench forms a continuous electrical path that passes through the inner and outer closed magnetic loops. 
     According to another exemplary embodiment, a method of integrating an inductor into a semiconductor is provided. The method includes providing a circular or other closed loop trench in a substrate, in which the trench is formed with sidewalls connected by a bottom surface in the substrate such that the trench forms a closed loop formation in the substrate. The method includes forming a first through silicon via (TSV) outside of the closed loop formation, forming a second through silicon via near a center of the closed loop formation, and depositing a first magnetic material layer on the sidewalls of the trench so as to coat the sidewalls and the bottom surface without filling the trench. The first magnetic material layer deposited on the sidewalls forms a first inner closed magnetic loop and a first outer closed magnetic loop within the trench. An electrical connection is formed between the first and second through silicon via, so as to define a continuous electrical path that passes from the first through silicon via to the second through silicon via and passes through the inner and outer closed magnetic loops. 
     Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the features, refer to the description and to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIGS. 1A through 1E  illustrate a fabrication process to form an embedded toroidal trench inductor structure according to an embodiment, in which: 
         FIG. 1A  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 1B  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 1C  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 1D  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 1E  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIGS. 2A through 2F  illustrate a fabrication process to form an embedded toroidal trench inductor structure according to an embodiment, in which: 
         FIG. 2A  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 2B  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 2C  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 2D  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 2E  illustrates a cross-sectional view and its corresponding top view of fabricating the toroidal trench inductor structure according to an embodiment. 
         FIG. 2F  illustrates an optional process that continues from  FIG. 2C  according to an embodiment. 
         FIGS. 3A and 3B  together illustrate a method of integrating an inductor into a semiconductor such as the substrate according to an embodiment. 
         FIG. 4  illustrates a method of integrating an inductor into a semiconductor according to an embodiment. 
         FIG. 5  illustrates a cross-sectional view that combines the embedded toroidal trench inductor structure in  FIG. 1  with the though silicon vias in  FIG. 2  according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     For high frequency integrated inductors, one needs a closed loop of magnetic material and a coil that passes through the closed loop. According to embodiments, examples are provided of a toroidal ring of magnetic material embedded flat in the substrate with a coil around the magnetic material. 
     In the present disclosure, this is done by making a circular or other closed loop trench and depositing magnetic material on the walls of the trench. There are two closed loops of magnetic material made at once: the interior and exterior walls. So instead of depositing twice to achieve one closed magnetic loop, the process herein deposits once and makes two closed loops of magnetic material. If there is more than one concentric trench loop, the result is that the process makes two more layers of magnetic material for each additional trench. This means one can get many (for multiple concentric loops) thin layers of magnetic material in one deposition step. The advantage of many thin magnetic layers is that the eddy current losses in the magnetic film are determined by the thickness of a film, while the overall inductance and magnetic saturation current increase with the amount of magnetic material. The ring trench approach allows for a high inductance in a small substrate surface area. It is noted that the trench should not be filled with conducting magnetic material as this shorts the interior and exterior walls of the magnetic layers together. 
     The coil (i.e., conductor material such as copper) has to pass through these loops of magnetic material. There are two ways to accomplish this: 
     1. Depositing conductor (usually copper) on the side walls and bottom of the trench so that there is path down the side of the trench, across the bottom and up the interior wall. This is like wrapping a very wide flat wire through the torroid. 
     2. Create separately silicon through visa (TSVs) by techniques understood by one skilled in the art and have one inside the magnetic loop and one outside, and then connect the two at the wafer back surface. Note that embodiments may use more TSVs and/or may use more copper layers with insulation in between to create additional coils and coil turns. 
     In order to facilitate the use of thin film magnetic material, embodiments ensure that the magnetic easy axis is oriented perpendicular to the wafer (substrate) surface. This is accomplished by applying a magnetic field perpendicular to the substrate plane during depositions and anneals. (Conventional systems have the applied magnetic filed and induced magnetic easy axis in the plane field of the substrate.) 
     Embodiments deposit a thin nonmagnetic layer (examples: NiP, Ta, TaN, TiN, Cu, Ni or other metal or insulator between 5 nm (nanometers) and 1000 nm) on top of the magnetic materials on the trench walls, and the deposit a second layer of magnetic material on the trench walls. A bilayer of magnetic material with a thin nonmagnetic separator has better magnetic domain properties. If the separator is insulating, implementations achieve twice the magnetic thickness without increased eddy current loss. If the separator is insulating, implementations may deposit an additional conducting seed layer when the magnetic layer is to be electroplated. 
     Some implementations may have more than one coil passing through the magnetic loops done by: 1) two layers of copper on the trench walls separated by insulator; 2) copper on the trench walls and coil(s) made using TSVs and substrate surface wires; and/or 3) two or more coils made using TSVs and substrate surface wires. 
     Having two or more coils allows for transformer and coupled inductor applications. Also, implementations may connect the coils in series to achieve more turns and a higher inductance. 
     In some implementations, the magnetic materials are insulated from the substrate, and the magnetic materials are insulated from the conductor (which improves performance). Also, after the magnetic material is deposited, the trench may then be filled in with a nonmagnetic, non-conducting material such as oxide or polymer. This allows wiring on the top surface and is required if the inductor is not connected to another substrate that contains a path to close the inductor coil loop. The trench loops may be circular which provides better magnetic properties. Also, the layers of magnetic material may be deposited by electroplating: this requires deposition of a continuous conducting seed layer that is removed after the magnetic film deposition. The magnetic properties are better (fewer domain walls) if the magnetic material is continuous from the walls across the bottom of the trench. 
     Now turning to the figures,  FIGS. 1A, 1B, 1C, 1D, and 1E  (generally referred to as  FIG. 1 ) illustrate a schematic to fabricate an embedded toroidal trench inductor structure  10  according to an embodiment. For the toroidal trench inductor structure  10 ,  FIGS. 1A through 1E  illustrate cross-sectional views on the left and corresponding top views on the right. 
       FIG. 1A  illustrates etching a substrate  100  to eventually form two concentric closed loop rings of magnetic material in per single (circular and/or closed loop) trench  150 . The substrate  100  may be silicon. Only one trench is shown but it is understood that two or more concentric (circular) trenches may be utilized as discussed herein. 
       FIG. 1B  illustrates depositing an oxide insulator  101  in the trench  150 . The sidewalls and bottom surface of the trench  150  are coated with the oxide insulator  101 . The oxide insulator  101  is also deposited on the top surface  160  of the substrate. A damascene groove  162  is etched into the oxide insulator  101  to define the wiring traces for connection to the inductor at the trench interior and exterior. Other materials are also deposited in the damascene groove  162  as discussed further in  FIG. 1 . Note that the oxide insulator  101  is deposited so as not to fill the trench  150  but to leave a cavity in the trench. The oxide insulator  101  material may have a thickness of 50 nm (nanometers) to 1000 nm on each sidewall and a thickness of 50 nm to 1000 nm on the bottom surface. 
       FIG. 1C  illustrates (optionally) depositing an adhesion layer/liner  102  on top of the coated oxide insulator  101  in the circular trench  150  and also on the top surface  160  of the substrate  100 . Examples of the adhesion layer/liner  102  include Ti/TiN, Ta/TaN, etc. The adhesion layer/liner  102  is deposited (and patterned) on the top surface  160  of the substrate  100  in the elongated pattern wiring trace  162  so as to fit within the rectangular shape of the (previously deposited) oxide insulator  101  material. Note that the adhesion layer/liner  102  is deposited on the sidewalls and bottom surfaces of the trench  150  so as to leave a cavity in the trench  150 . The adhesion layer/liner  102  may have a thickness of 10 nm to 1000 nm on each sidewall and a similar thickness on the bottom surface. 
     After depositing the adhesion layer/liner  102  in the trench  150 , a conductor layer  103  is deposited on the coated adhesion layer/liner  102  in the trench  150  and also on the top surface  160  of the substrate  100 . A seed metal may be applied first to grow the conductor layer  103 . Examples of the conductor layer  103  include copper, aluminum, Ni, NiFe, Co, CoW. Note that if a magnetic film is to be plated, a magnetic seed material (metal) is desirable first (even in  FIG. 2  below), and in one case, the magnetic seed may be a bilayer with copper for conductivity and then magnetic material. The conductor layer  103  is deposited on the top surface  160  of the substrate  100  so as to fill the damascene groove or wiring trace  162 . Excess conductor and seed on the surface outside the groove  162  can then be removed by CMP (chemical-mechanical-polishing). Alternatively, the damascene groove  162  can be omitted from the design, and the conductor plating region restricted to the wiring traces may be formed with a photopatterned photoresist layer in which case the excess seed is removed by etching following the removal of the photoresist. Note that the conductor layer  103  is deposited so as to leave a cavity in the trench  150 . The conductor layer  103  may have a thickness of 50 nm to 1000 nm on each sidewall on the bottom surface. Since there may be some reduction in thickness on the trench bottom, the deposition thickness may be chosen to achieve a minimum thickness of 25 nm on the trench bottom. As a result of deposition, the conductor layer  103  has an inner closed loop of conductor material lining the inner sidewall and an outer closed loop of conductive material lining the outer sidewall of the trench  150 . The inner closed loop of the conductor layer  103  and the outer closed loop of the conductor layer  103  are connected by the bottom surface of conductor layer  103  at the bottom of the trench. 
       FIG. 1D  illustrates depositing a second insulator  104  on top of the coated conductor layer  103  in the trench  150  and also on the top surface  160  of the substrate  100 . Examples of the insulator  104  include silicon dioxide, SiN, SiCNi, polyimide, and polybenzoxazole (PBO). The insulator  104  is deposited on the top surface  160  of the substrate  100  in the elongated pattern wiring trace  162  so as to fit within the rectangular shape of the (previously deposited) oxide insulator  101 , the adhesion layer/liner  102 , and conductor layer  103 . Note that the second insulator  104  is deposited in the trench  150  so as to leave a cavity in the trench  150 . The second insulator material  104  may have a thickness of 10 nm to 1000 nm on each sidewall and on the bottom surface. 
     After depositing the second insulator  104  within the trench  150 , a seed metal  105  is deposited on the coated insulator  104  in both the trench  150  and also on the top surface  160  of the substrate  100 . Examples of the seed metal  105  copper, aluminum, Ni, NiFe, Co, and CoW. The seed metal  105  is deposited on the top surface  160  of the substrate  100 . Note that the seed metal  105  is deposited in the trench  150  so as leave a cavity in the trench  150 . The seed metal  105  may have a thickness of 10 nm to 1000 nm on each sidewall and on the bottom surface. 
     A photomask  106  is deposited on the top surface  106  as a pattern for depositing a magnetic film  107 . The photomask  106  covers the entire substrate  100  (including the elongated pattern wiring trace  162 ) except for the trench  150 . The magnetic film  107  is deposited on the coated seed metal  105  in the trench  150  and also on the top surface  160  of the substrate  100 . The magnetic film  107  is magnetic material. The magnetic film  107  is deposited and/or thermally annealed within (the presence) of a vertical (perpendicular to the substrate plane) magnetic field  120  (represented by an arrow) such that the magnetic film  107  has an induced magnetic anisotropy, which means that the easy axis of the magnetic film  107  is aligned with the magnetic field and is perpendicular to the (horizontal) plane of the substrate. The magnetic material of the magnetic film  107  may be deposited by electroplating. Examples of the magnetic film  107  include NiFe, CoWP, Fe, CoFeB, etc. The magnetic film  107  is not deposited on the top surface  160  of the substrate  100  in the elongated pattern  162  or at least is removed when the photomask  106  is removed. Note that the magnetic film  107  is deposited in the trench  150  so as to leave a cavity in the trench  150 . The magnetic film  107  may have a thickness of 100 nm to 3000 nm on each sidewall and on the bottom surface. If plating or deposition process limitations cause the film thickness to vary and be thinner on and near the bottom of the trench, this is undesirable. In this case, the inductor will still work albeit with smaller inductance even if the magnetic film  107  thickness is zero on the trench bottom. The magnetic film  107  has an inner closed loop of magnetic material lining the inner sidewall and an outer closed loop of magnetic material lining the outer sidewall of the trench  150 . These the inner and outer closed loops of magnetic film  107  are two magnetic laminate layers currently deposited in the trench  150 . 
       FIG. 1E  illustrates removing the photomask  106 . A photopatterned insulator  108  is deposited to fill in the trench  150  and as an overcoat on top of the substrate  100 . Examples of the photopatterned insulator  108  may include photosensitive-polyimide (PSPI), polybenzoxazole (PBO), etc. 
     Two via openings  109 A and  109 B are opened (i.e., etched) down to the conductor layer  103  on the elongated rectangular pattern (portion)  162 , such that the conductor layer  103  is exposed at two separate locations on the elongated pattern  162 . The via opening  109 A is on the outside of the circular trench  150  while the via opening  109 B is in about the center of the circular formation made by the circular trench. The toroidal trench inductor structure  10  is complete and can be connected further by depositing wiring over the via openings  109 A and  109 B. 
     As noted above, the conductor layer  103  has the inner closed loop of conductive material lining the inner sidewall and the outer closed loop of conductive material lining the outer sidewall of the trench  150 , along with the bottom surface of conductor layer  107  connecting the inner and outer loops of conductor material. Via the elongated pattern  162 , the opening  109 A is configured so that one polarity (e.g., positive) of a voltage source electrically connects to the outer closed loop of conductor layer  103  while the opening  109 B is configured so that the opposite polarity (e.g., negative) of the voltage source electrically connects to the inner closed loop of the conductor layer  103 . When the voltage source is turned on, electrical current flows from the positive side of the voltage source, into the opening  109 A, through the elongated pattern  162 , down the outer closed loop of conductor layer  103  in the trench  150 , through the bottom conductor layer  103  on the bottom surface in the trench  150 , up the inner closed loop of conductor layer  103 , out the elongated pattern  162 , and out the opening  109 B back to the voltage source. Note that the elongated pattern wiring trace  162  has a first exterior conductor connection  164 A that connects (electrically) to the conductor layer  103  at the inside wall (i.e., the inner closed loop of the conductor layer  103 ) of the trench  150 . Also, the elongated pattern wiring trace  162  has a second exterior conductor connection  164 B that separately (electrically) connects to the conductor layer  103  formed on an outside wall of the trench  150 . 
     According to another embodiment,  FIGS. 2A, 2B, 2C, 2D, 2E, and 2F  (generally referred to as  FIG. 2 ) illustrate a schematic to fabricate an embedded toroidal trench inductor structure  20 . For the toroidal trench inductor structure  20 ,  FIGS. 2A through 2F  illustrate cross-sectional views on the left and corresponding top views on the right. 
       FIG. 2A  illustrates forming two through silicon vias (TSVs)  201 A and  201 B etched into a substrate  200  as understood by one skilled in the art. The substrate  200  (or  100  in  FIG. 1 ) may be a silicon wafer. Other substrates may include glasses, SiO 2 , polymers (such as polymide, SiC, tungsten carbide, titanium carbide, and N58), and aluminum oxide. The TSVs  201 A and  201 B are vertical electrical connections also referred to as vertical interconnect vias. The TSVs  201 A and  201 B are filled with conductor material  26  surrounded by insulating material  28 . When the substrate is not silicon, the through silicon vias (TSVs) can be replaced with other through-substrate-via structures, as the utilization of the through silicon via structure is not a requirement. An example would be the copper filled vias used with glass substrates. 
     Back end of line (BEOL) wiring  202  is deposited on top of the substrate  200  including the TSVs  201 A and  201 B. The BEOL wiring  202  may be metal wiring such as copper, aluminum, gold, etc. An optional handler  203  is attached to the top of the substrate  200  including the BEOL wiring  202 . The handler  203  is an additional substrate attached temporarily to the wafer with an adhesive to give structural support during processing of a thinned wafer. If the thinned wafer thickness is sufficient for mechanical stability during processing it may not be necessary. Handlers are most commonly silicon-thermal-expansion-matched borosilicate glass or silicon. 
       FIG. 2B  shows that that the substrate  200  is flipped over and the substrate  200  (wafer) is thinned, e.g., by polishing, to expose the TSVs  201 A and  201 B. A circular trench  204  (as discussed above) is etched into the substrate  200  to form a ring. The exposed TSV  201 A is outside (i.e., to the exterior) of the trench  204 . The circular trench  204  encircles the TSV  201 B. Since the substrate (wafer)  200  has been flipped over, the previous bottom side will now be referred to as the top side, such that the handler  203  is now on the bottom side. 
       FIG. 2C  illustrates depositing a blanket deposit of seed  205  in the trench  204 . The sidewalls and bottom surface of the trench  204  are coated with the seed  205 . The seed  205  is also deposited on a top surface  260  of the substrate  200 . Note that the seed  205  is deposited in the trench  204  so as to leave a cavity in the trench  204 . Examples of the seed  205  include Ti/TiN, TaTaN, Cu, Ni, NiFe, Co, CoW, and/or several of these materials deposited in sequence or other conducting materials. The seed  205  material may have a thickness of 10 to 1000 nm on each sidewall and on the bottom surface. Some reduction in thickness on the trench bottom due to process limitations can be tolerated as long as the film is continuous. 
     Additionally, photomask  206  is deposited and patterned on the substrate  200  in  FIG. 2C . The photomask  206  covers the entire substrate  200  except for the trench  204 . A (first) magnetic film  207  is deposited on (and/or grown from) the seed  205  in the trench  204 . The magnetic film  207  is magnetic material. The magnetic film  207  is deposited and/or thermally annealed within (the presence) of a magnetic field  220  (represented by an arrow) such that the magnetic film  207  has an magnetic anisotropy or “easy axis” of the magnetic film  207  that is perpendicular to the substrate plane. The magnetic material of the magnetic film  207  may be deposited by electroplating. Examples of the magnetic film  207  include NiFe, CoWP, Fe, CoFeB, etc. The magnetic film  207  is not deposited on the top surface  260  of the substrate  200  except as desired to allow for alignment tolerances, or in the case when multiple concentric trenches are used, the magnetic material can be continuous between trenches. Note that the magnetic film  207  is deposited in the trench  204  so as to leave a cavity in the trench  204 . The magnetic film  207  may have a thickness of 100 to 3000 nm on each sidewall and on the bottom surface. If plating or deposition process limitations cause the film thickness to vary and be thinner on and near the bottom of the trench, this is undesirable. In this case, the inductor will still work albeit with smaller inductance even if the magnetic film thickness is zero on the trench bottom. The magnetic film  207  has an inner closed loop of magnetic material lining the inner sidewall and an outer closed loop of magnetic material lining the outer sidewall of the trench  204 . 
     In an alternate method, the magnetic film  207  is not a single magnetic layer but instead is formed as a coupled magnetic multilayer where the a first magnetic layer of half the intended thickness is deposited, then a nonmagnetic conductor such as NiP or Cu is deposited to a thickness between 10 nm and 1000 nm, and a second magnetic film making up the remaining magnetic material is deposited. An example is the NiFe/NiP/NiFe coupled magnetic film where the plating conditions are changed during electroplating to alter the material composition. Coupled magnetic films have improved magnetic domain properties as known to those skilled in the art. 
       FIG. 2D  illustrates that the cavity in the magnetic film  207  in the trench  204  is going to be filled. Also, the photomask  206  is etched away and the seed  205  on the top surface  260  is etched away. 
     Now, a blanket of oxide  208  is deposited on the top surface  260 . The oxide layer  208  covers the entire the top surface  260  of the substrate  200 . The oxide layer  208  is deposited on the coated magnetic film  207  in the trench  204 . Note that the oxide layer  208  is deposited in the trench  204  so as to leave a cavity in the trench  204 . The oxide layer  208  may have a thickness of 10 nm to 1000 nm on each sidewall and on the bottom surface. 
     A blanket of seed  209  is deposited on the top surface  260 . The seed  209  covers the entire the top surface  260  of the substrate  200 . The seed  209  is deposited on the oxide layer  208  in the trench  204 . Note that the seed  209  is deposited in the trench  204  so as to leave a cavity in the trench  204 . The seed  209  material may have a thickness of 10 to 1000 nm on each sidewall on the bottom surface. 
     Also, a photomask  210  is deposited and patterned on the top surface  260  of the substrate  200 , so as to leave an opening for depositing a (second) magnetic film  211  in the trench  204 . The magnetic film  211  is deposited on (and/or grown from) the coated seed  209 . The magnetic film  211  is magnetic material (which may be the same magnetic material or different magnetic material than the magnetic film  207 ). The magnetic film  211  is deposited within (the presence) of the magnetic field  220  (represented by an arrow) such that the magnetic film  207  has an anisotropy direction perpendicular to the wafer surface. Examples of the magnetic film  211  include NiFe, CoWP, Fe, CoFeB, etc. The magnetic film  211  is not deposited on the top surface  260  of the substrate  200 , and the magnetic film  211  leaves a cavity in the trench  204 . The magnetic film  211  may have a thickness 100 to 3000 nm on each sidewall and on the bottom surface. If plating or deposition process limitations cause the film thickness to vary and be thinner on and near the bottom of the trench this is undesirable. The inductor will still work albeit with smaller inductance even if the magnetic film thickness is zero on the trench bottom. The magnetic film  211  also has an inner closed loop of magnetic material lining the inner sidewall and an outer closed loop of magnetic material lining the outer sidewall of the trench  204 . 
     The process discussed in  FIG. 2D  may be repeated (multiple times) to build up more laminated magnetic film layers  211  in the trench  204 . Currently, two magnetic film layers  207  and  211  are shown which result in four closed loops of magnetic material. 
       FIG. 2E  illustrates that the photomask  210  is etched away and the seed  209  (only) on the top surface  260  is etched away. An insulator  228  is applied on the top surface  260  and to fill the trench  204 . The insulator  228  and insulator  208  are patterned/etched to expose the inductor electrical contacts which are the TSVs  201 A and  201 B. Examples of the insulator  228  may include photosensitive-polyimide (PSPI), polybenzoxazole (PBO), etc. Although not shown, the process may continue by adding wiring, pads, and solder balls as understood by one skilled in the art. When complete, the handler  203  is removed. 
     Optionally,  FIG. 2D  (and  FIG. 2E ) may be skipped in one implementation and the process may flow directly from  FIG. 2C  to  FIG. 2F . In that case,  FIG. 2F  illustrates that that the deposition of the magnetic film  207  in the trench  204  leaves a cavity to be filled. Also, the photomask  206  is etched away and the seed  205  on the top surface  260  is etched away. The insulator  228  is applied on the top surface  260  and to fill the trench  204 . The insulator  228  is patterned to expose the inductor electrical contacts which are the TSVs  201 A and  201 B. Examples of the  228  may include photosensitive-polyimide (PSPI), polybenzoxazole (PBO), etc. Although not shown, the process may continue with by adding wiring, pads, and solder balls as understood by one skilled in the art. When complete, the handler  203  is removed. The implementation in  FIG. 2F  only has one application/deposition of magnetic film layer  207  which results into two closed loops of magnetic material (i.e., two magnetic laminate layers). 
     It is noted that the magnetic materials discussed herein may be deposited by any method such as sputtering, evaporation, CVD, electroplating, and electroless plating. Further,  FIG. 5  illustrates a cross-sectional view  500  that combines the embedded toroidal trench inductor structure  10  with the TSV  201 A and  201 B from  FIG. 2  according to an embodiment. Reference can be made to  FIGS. 1 and 2  discussed above. The inductor  10  shown in  FIG. 5  provides a two coil structure that is useful for coupled inductors. As discussed in  FIG. 1E , the elongated pattern wiring trace  162  (via the first exterior conductor connection  164 A) electrically connects to the conductor layer  103  at the inside wall (i.e., the inner closed loop of the conductor layer  103 ) of the trench  150 . Also, the elongated pattern wiring trace  162  (via the second exterior conductor connection  164 B) separately connects electrically to the conductor layer  103  formed on an outside wall of the trench  150 . In addition to that (first) electrical path formed by the wiring trace  162  in  FIG. 1 , the through silicon vias  201 A and  201 B along with BEOL  202  for a separate electrical path. For example, the first through silicon via (TSV)  201 A is formed outside of the circular trench  150 , and the second through silicon  201 B is formed near the center of the circular trench  150 . An electrical connection is formed between the first and second through silicon vias (and the BEOL  202 ), so as to define a continuous electrical path that passes from the first through silicon via  201 A to the second through silicon via  201 B and passes through the inner and outer closed magnetic loops. 
       FIGS. 3A and 3B  together illustrate a method  300  of integrating the inductor  10  into a semiconductor such as the substrate  100  according to an embodiment. Reference can be made to  FIG. 1 . The method includes providing a circular trench  150  in the substrate  100 , where the trench  150  is formed with sidewalls connected by a bottom surface in the substrate  150  at block  305 . 
     At block  310 , a first insulator layer  101  is deposited on the sidewalls of the trench  150  so as to coat the sidewalls and the bottom surface. At block  315 , a conductor layer  103  is deposited on the sidewalls and the bottom surface of the trench  150  so as to coat the first insulator layer  101  in the trench such that the conductor layer  103  is on top of the first insulator layer  101  in the trench. 
     At block  320 , a second insulator layer  104  is deposited on top of the conductor layer  103  on the sidewalls and the bottom surface of the trench  150 . At block  325 , magnetic material  107  is deposited on the sidewalls and the bottom surface of the trench  150  so as to coat the second insulator layer  104  in the trench  150  without filling the trench. Note that the seed layer  105  is optional for electroplating. 
     At block  330 , the conductor layer  103  deposited on the sidewalls forms an inner closed loop (i.e., the closed loop of conductor layer  103  material on the inner wall of the trench  150 ) and an outer closed loop (i.e., the closed loop of conductor layer  103  material on the outer wall of the trench  150 ) within the trench  150  connected by a bottom conductor layer  103  on the bottom surface of the trench  150 , in which the inner closed loop, the outer closed loop, and the bottom conductor layer  130  form an interior conductor path inside the trench  150 , such that the interior conductor path passes underneath and around sides of the magnetic material  107  in the trench  150 . Note that the magnetic material  107  also has its own inner closed loop and outer closed loop easier seen when viewed from a top view. 
     At block  335 , the interior conductor path inside the trench  150  connects to an exterior conductor path (which is the wiring trace  162  of the conductor layer  130 ), and the exterior conductor path separately connects to the inner loop of the conductor layer  103  (by the wiring trace  162  of the conductor layer  103  on the surface  160  encircled by the trench  150  connecting to the inner wall of the conductor layer  103  in the trench  150 ) and the outer loop of the conductor layer  103  (by the elongated pattern  162  of the conductor layer  103  on the surface  160  not encircled by the trench  150  connecting to the outer wall of the conductor layer  103  in the trench  150 ). 
     The exterior conductor path is a wiring trace  162  of the conductor layer  103  applied on a top surface  160  of the substrate  100 . The wiring trace  162  of the conductor layer  130  is concurrently deposited on the top surface of substrate  100  (but is not in the trench  150 ) when depositing the conductor layer  130  inside the trench  150 . 
     The method can continue by depositing a third insulator layer (just like insulator layer  104  but within the previously deposited magnetic material  107 ) on the sidewalls and the bottom surface of the trench  150  so as to coat the magnetic material  107  in the trench  150  without filling the trench  150 , and then depositing a second magnetic material (just as the magnetic material  107  was previously deposited on/grown from the seed material  105 ) on the sidewalls and the bottom surface of the trench  150  so as to coat the third insulator layer in the trench  150  without filling the trench  150 . 
     A magnetic field  120  aligned perpendicular to the substrate plane is applied while depositing the magnetic material  107  and/or during a subsequent thermal anneal causing the magnetic material to have an induced anisotropy perpendicular (i.e., vertical) to the plane of the substrate  100 . 
     The method where depositing the magnetic material  107  comprises a coupled magnetic film made by electroplating NiFe as the magnetic material, subsequently electroplating NiP, and then electroplating NiFe again in a (single) continuous electroplating process of the magnetic material  107 . An alternative method where the magnetic layer is a coupled magnetic film as known in the art where the magnetic film has sublayers made by depositing a magnetic material, subsequently electroplating a conducting nonmagnetic material, and then electroplating another magnetic layer. For eddy current purposes the two layers together need to be thin enough to avoid eddy current losses and then multiple pairs of these magnetic bilayers are built up separated by having an insulator in between. The nonmagnetic material would be a conductor which means one does not need to deposit a new adhesion layer and seed metal. Nonmagentic layers include Ni, Cu, NiP, Ta, Ti, and others. 
       FIG. 4  illustrates a method  400  of integrating an inductor  20  into a semiconductor (substrate  200 ) according to an embodiment. The method includes providing a circular trench  204  in the substrate  200 , where the trench  204  is formed with sidewalls connected by a bottom surface in the substrate  200  such that the trench forms a circular formation in the substrate  200  at block  405 . 
     A first through silicon via (TSV)  201 A is formed outside of the circular formation at block  410 , and a second through silicon via  201 B is formed near a center of the circular formation at block  415 . In one case, note that the first and second through silicon vias  201 A and  201 B may be formed prior to the trench  204 . 
     A first magnetic material layer  207  is deposited on the sidewalls of the trench  204  so as to coat the sidewalls and the bottom surface without filling the trench  204  at block  420 . The first magnetic material layer  207  deposited on the sidewalls forms a first inner closed loop and a first outer closed loop within the trench  204  at block  425 . 
     The method includes depositing a first insulator layer  208  on the sidewalls and the bottom surface of the trench  204  so as to coat the first magnetic material layer  207  in the trench  204  such that the first insulator layer  208  is on top of the first magnetic material layer  207  in the trench  204  without filling the trench. The method includes depositing a second magnetic material layer  211  (seed layer  209  is optional) on top of the first insulator layer  208  on the sidewalls and the bottom surface of the trench  204  without filling the trench. The second magnetic material  211  is deposited on the sidewalls and the bottom surface of the trench  204  so as to coat the first insulator layer  208  in the trench  204  without filling the trench. Note that the seed material  205  may be deposited first when electroplating the second magnetic material  211 . 
     The second magnetic material layer  211  deposited on the sidewalls forms a second inner closed loop and a second outer closed loop within the trench. A (top) second insulator  228  is deposited to fill in the trench  204  and cover the surface of the substrate  200 . The method includes etching two separate openings  201 A and  201 B in the second insulator  228  and first insulator  208  to expose both the first through silicon via  201 A and the second through silicon via  201 B through the second insulator  228 . 
     For illustration purposes, various deposition techniques are discussed below and can be utilized in embodiments, as understood by one of ordinary skill in the art. Thin film deposition is the act of applying a thin film to a surface which is any technique for depositing a thin film of material onto a substrate or onto previously deposited layers. Thin is a relative term, but most deposition techniques control layer thickness within a few tens of nanometers. Molecular beam epitaxy allows a single layer of atoms to be deposited at a time. Deposition techniques fall into two broad categories, depending on whether the process is primarily chemical or physical. Chemical vapor deposition utilizes a fluid precursor that undergoes a chemical change at a solid surface, leaving a solid layer. Chemical deposition is further categorized by the phase of the precursor and examples of chemical deposition include, but are not limited to: plating; chemical solution deposition (CSD) or chemical bath deposition (CBD); spin coating or spin casting; chemical vapor deposition (CVD); plasma enhanced CVD (PECVD); atomic layer deposition (ALD); and so forth. 
     Physical vapor deposition (PVD) uses mechanical, electromechanical, or thermodynamic means to produce a thin film of solid. Examples of physical deposition include but are not limited to: a thermal evaporator (i.e., molecular beam epitaxy); an electron beam evaporator; sputtering; pulsed laser deposition; cathodic arc physical vapor deposition (arc-PVD); electrohydrodynamic deposition (electrospray deposition); reactive PVD; and so forth. 
     Note that eddy currents are electric currents induced within conductors by a changing magnetic field in the conductor. These circulating eddies of current have inductance and thus induce magnetic fields. The stronger the applied magnetic field, the greater the electrical conductivity of the conductor, or the faster the field changes, then the greater the eddy currents that are developed and the greater the fields produced. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 
     The diagrams depicted herein are just one example. There may be many variations to this diagram or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention. 
     While the preferred embodiment to the invention had been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.