BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a top view of a primary winding of a high coupling factor transformer according to an embodiment of the present invention.
FIG. 1B is a top view of a secondary winding of a high coupling factor transformer according to an embodiment of the present invention.
FIG 1C is a top view of an entire high coupling factor transformer according to an embodiment of the present invention.
FIG. 1D is a stereogram of a high coupling factor transformer according to an embodiment of the present invention.
FIG. 2 is a top view of a transformer according to another embodiment of the present invention.
FIG. 3A is a top view of the primary winding of a high coupling factor transformer according to another embodiment of the present invention.
FIG. 3B is a top view of the secondary winding of a high coupling factor transformer according to another embodiment of the present invention.
FIG. 3C is a top view of the entire high coupling factor transformer according to another embodiment of the present invention.
FIG. 4A-4D are top views of another high coupling factor transformer according to an embodiment of the present invention.
FIG. 5 is a stereogram illustrating the sectional view Line A of the protruding portions in the transformer in FIG. 4D.
FIG. 6A illustrates the characteristic of the coupling factor k of the transformer 400 in FIG. 4D when the measured frequency is between 0-20GHz.
FIG. 6B illustrates the characteristic of the coupling factor k of the transformer in FIG. 6A when the frequency is ranged between 0-3.5GHz.
FIG. 7 illustrates the layout of a general transformer.
FIG. 8A illustrates the characteristic of the coupling factor k of the transformer in FIG.7.
FIG. 8B illustrates the characteristic of the coupling factor k of the transformer in FIG.8A when the frequency is ranged between 0-3.5GHz.
DESCRIPTION OF EMBODIMENTS
FIGS. 1A-1D show a high coupling factor transformer according to an embodiment of the present invention. FIG. 1A is a top view of a primary winding 101 of a high coupling factor transformer 100 according to an embodiment of the present invention, FIG. 1B is a top view of a secondary winding 102 of the high coupling factor transformer 100, FIG. 1C is a top view of the entire high coupling factor transformer 100 which is formed by stacking the secondary winding 102 above the primary winding 101, and FIG. 1D is a stereogram of the entire high transformer 100.
Referring to FIGS. 1A-1D, the transformer 100 comprises a primary winding 101 and a secondary winding 102. The secondary winding 102 is adjacent to the primary winding 101, and the primary winding 101 and the secondary winding 102 induct with each other. In the present embodiment, the primary winding 101 of the transformer 100 is substantially disposed on a first plane, and the secondary winding 102 is substantially disposed on a second plane, wherein the first plane is parallel to the second plane. If the first plane is the fourth metal layer, the second plane is the fifth metal layer. Those of ordinary skill in the art would appreciate that the primary winding 101 and the secondary winding 102 may also be disposed on any two metal layers in an integrated circuit as required.
The primary winding 101 comprises a plurality of first protruding portions 111 and a plurality of first openwork slots 112. The first protruding portions 111 are disposed on the primary winding 101, and the first end of each of the first protruding portions is electrically connected to the primary winding 101. The secondary winding 102 comprises a plurality of second protruding portions 121 and a plurality of second openwork slots 122. The second protruding portions 121, indicated by dashed-line frames in FIG. 1B, are disposed under the secondary winding 102. The second protruding portions 121 extend from the secondary winding 102 to the primary winding 101. The first ends of the second protruding portions 121 are disposed in the first openwork slots and the second protruding portions 121 are not electrically connected to the primary winding 101. The second ends of the second protruding portions 121 are electrically connected to the secondary winding 102. The first protruding portions 111 extend to the secondary winding 102. The arrangement position of the second openwork slots 122 can just accommodate the second ends of the first protruding portions 111, and the first protruding portions 111 are not electrically connected to the secondary winding 102. The first protruding portions 111 and the second protruding portions 121 can be achieved by vias. The first protruding portions 111 and the second protruding portions 121 can be conductors having cuboidal shape, cylindrical shape, or other geometrical shapes. In the present embodiment, the first protruding portions 111 and the second protruding portions 121 are respectively arranged in the primary winding 101 and the secondary winding 102 in a single row. As shown in the figure, the first protruding portions 111 and the second protruding portions 121 are interdigitated with one another between the primary winding 101 and the secondary winding 102.
Each of the protruding portions extends into one of the openwork slots in “one-to-one” manner, but the implementation of the present invention is not limited as such. For example, a designer can make two or more protruding portions extend into one openwork slot.
In the transformer, the arrangement of the protruding portions of the primary winding and the secondary winding is not limited to those described in the above embodiment. Those of ordinary skill in the art would appreciate that the protruding portions of the primary winding and the secondary winding may be arranged in a single row, double rows, multiple rows, or in other geometrical arrangements. FIG. 2 is a top view of the transformer according to another embodiment of the present invention. The transformer 200 is formed by stacking the secondary winding 202 above the primary winding 201. The present embodiment is similar to the embodiment described above, those not described in the present embodiment can be implemented with reference to the above embodiment. The primary winding 201 of the transformer 200 is substantially disposed on the first plane, and the secondary winding 202 is substantially disposed on the second plane, wherein the first plane is parallel to the second plane. The primary winding 201 comprises a plurality of first protruding portions 211 and a plurality of first openwork slots 212. The first protruding portions 211 are disposed on the primary winding 201 and the first end of each of the protruding portions 211 is electrically connected to the primary winding 201. The secondary winding 202 comprises a plurality of second protruding portions 221 and a plurality of second openwork slots 222. In the present embodiment, the first protruding portions 211 and the second protruding portions 221 are arranged in double rows and interdigitated with one another between the primary winding 101 and the secondary winding 102.
The number of turns of the primary winding and the secondary winding are not limited. Those of ordinary skill in the art would appreciate that the transformer may be implemented in any number of turns as required. FIG. 3A-3C are top views of a high coupling factor transformer according to another embodiment of the present invention. The transformer 300 is formed by stacking a primary winding 301 above a secondary winding 302. FIG. 3A is a top view of the primary winding 301 of the high coupling factor transformer 300 according to another embodiment of the present invention. FIG. 3B is a top view of the secondary winding 302 of the high coupling factor transformer 300 according to another embodiment of the present invention. FIG. 3C is a top view of the entire high coupling factor transformer 300 according to another embodiment of the present invention. Those not described in the present embodiment can be implemented with reference to the above embodiment.
Referring to FIGS. 3A-3C, the transformer 300 comprises the primary winding 301 and the secondary winding 302. The secondary winding 302 is adjacent to the primary winding 301, and the secondary winding 302 and the primary winding 301 induct with each other. In the present embodiment, the primary winding 301 of the transformer 300 is substantially disposed on the first plane and the secondary winding 302 is substantially disposed on the second plane, wherein the first plane is parallel to the second plane.
Referring to FIG. 3A, the primary winding 301 is substantially disposed on the first plane. Since the primary winding 301 is a planar inductor with three turns, a part of electrical paths (such as electrical paths 331 and 334) in the primary winding 301 must be disposed on other planes. For example, if the first plane is the fourth metal layer, a part of the electrical paths 331 and 334 of the primary winding 301 can be disposed on the fifth metal layer. The electrical path 331 can be electrically connected to the primary winding 301 through the vias 332 and 333. Additionally, the electrical path 334 can also be electrically connected to the primary winding 301 through the vias 335 and 336. The primary winding 301 comprises a plurality of first protruding portions 311 and a plurality of first openwork slots 312. The first protruding portions 311, indicated by dashed-line frames in FIG. 3A, are disposed under the secondary winding 301, and the first end of each of the first protruding portions 311 is electrically connected to the primary winding 301.
Referring to FIG. 3B, the secondary winding 302 is substantially disposed on the second plane. Since the secondary winding 302 is also a planar inductor with three turns, a part of electrical paths (such as electrical paths 341 and 344) in the secondary winding 302 must be disposed on other planes. For example, if the second plane is the third metal layer, a part of the electrical paths 341 and 344 of the secondary winding 302 are disposed on the second metal layer. The electrical path 341 can be electrically connected to the secondary winding 302 through the vias 342 and 343. Additionally, the electrical path 344 can also be electrically connected to the secondary winding 302 through the vias 345 and 346. Those of ordinary skill in the art would appreciate that the primary winding 301 and the secondary winding 302 may be disposed on any two metal layers in an integrated circuit as required.
Referring to FIGS. 3A-3C, the secondary winding 302 comprises a plurality of second protruding portions 321 and a plurality of second openwork slots 322. The second protruding portions 321 are disposed on the secondary winding 302. The second protruding portions 321 extend from the secondary winding 302 to the primary winding 301. The first ends of the second protruding portions 321 are disposed in the first openwork slots 312, and the second protruding portions 312 are not electrically connected to the primary windings 301. The second ends of the second protruding portions 312 are electrically connected to the secondary winding 302. The first protruding portions 311 extend to the secondary winding 302. The arrangement position of the second openwork slots 322 can just accommodate the second ends of the first protruding portions 311, and the first protruding portions 311 are not electrically connected to the secondary windings 302. The first protruding portions 311 and the second protruding portions 321 can be achieved by vias. The first protruding portions 311 and the second protruding portions 321 can be conductors of cuboidal shape, cylindrical shape, or other geometrical shapes. In the present embodiment, the first protruding portions 311 and the second protruding portions 321 are respectively arranged on the primary winding 301 and the secondary winding 302 in a single row. As shown in the figure, the first protruding portions 311 and the second protruding portions 321 are interdigitated with one another between the primary winding 301 and the secondary winding 302.
Each of the protruding portions extends into one of the openwork slots in “one-to-one” manner in the above embodiment, but the implementation of the present invention is not limited to this. For example, a designer can make two or more protruding portions extend into one openwork slot. In the transformer, the arrangement of the protruding portions of the primary winding and the secondary winding is not limited to those described in the above embodiment. Those of ordinary skill in the art would appreciate that the protruding portions of the primary winding and the secondary winding may be arranged in a single row, double rows, multiple rows, or in other geometrical arrangements.
The method of manufacturing the transformer comprises forming the primary winding substantially on the first plane, wherein the primary winding comprises a plurality of first openwork slots. Then, a plurality of first protruding portions and a plurality of second protruding portions are formed above the primary winding. Each of the first protruding portions is disposed on the primary winding and the first end of each of the first protruding portions is electrically connected to the primary winding. And the first ends of the second protruding portions are disposed in the first openwork slots, and each of the second protruding portions is not electrically connected to the primary winding. Finally, the secondary winding is substantially formed the second plane, wherein the secondary winding comprises a plurality of second openwork slots. The second openwork slots are disposed on the second ends of the first protruding portions, and each of the first protruding portions is not electrically connected to the secondary winding. The second ends of the second protruding portions are electrically connected to the secondary winding.
In the present invention, the first and second protruding portions can have a cuboidal shape, cylindrical shape, or other columnar shape. The first and second protruding portions can be arranged in single row or multiple rows respectively on the primary winding and the secondary winding. The first protruding portions and the second protruding portions are interdigitated with one another between the primary winding and the secondary winding, or disposed between the primary winding and the secondary winding in other manners.
According to another embodiment of the present invention, the primary winding is substantially disposed on a first plane and the secondary winding is substantially disposed on a second plane, wherein the first plane is parallel to the second plane.
According to another embodiment of the present invention, each of the first protruding portions extends into one of the second openwork slots in one-to-one manner, and each of the second protruding portions extends into one of the first openwork slots in one-to-one manner. However, a designer can make two or more protruding portions stretch into one openwork slot.
Those skilled in the art shall be able to implement the present invention by using other embodiments according to the spirit, teachings and suggestions of the present invention described above. For example, FIG. 4A˜4C are top views of another high coupling factor transformer according to an embodiment of the present invention. The transformer 400 includes the primary winding 401 and the secondary winding 402. Wherein, FIG. 4A illustrates the layout of the third plane 400-3 of the transformer 400, FIG. 4B illustrates the layout of the second plane 400-2 of the transformer 400, and FIG. 4C illustrates the layout of the first plane 400-1 of the transformer 400. The primary winding 401 of the transformer 400 is substantially disposed on the first plane 400-1 and the third plane 400-3, and the secondary winding 402 is substantially disposed on the second plane 400-2. Wherein, the second plane 400-2 is located between the first plane 400-1 and the third plane 400-3, and the three planes are parallel one another. The first plane 400-1, the second plane 400-2 and the third plane 400-3 can be any layer of the conductive layers, such as a metal layer or a polysilicon layer. For example, the first plane 400-1 is the sixth metal layer M6, the second plane 400-2 is the seventh metal layer M7, and the third plane 400-3 is the eighth metal layer M8. FIG. 4D is a top view of the entire transformer 400. Those not described in the present embodiment can be implemented with reference to the above-described embodiment.
The primary winding includes a plurality of protruding portions 410. The secondary winding includes a plurality of openwork slots 420. Wherein, the protruding portions 410 of the primary winding 401 extend to the openwork slots 420 of the secondary winding 402, and the primary winding and the secondary winding are not electrically connected. FIG. 5 is a stereogram illustrating the sectional view Line A of the protruding portions in the transformer in FIG. 4D. The electrical paths on the first plane 400-1 and the third plane 400-3 of the primary winding 401 are electrically connected through a plurality of the protruding portions 410. The protruding portions 410 penetrate the openwork slots 420, and the protruding portions 410 and the secondary winding 402 are not electrically connected. The protruding portions 410 can be achieved by vias. The protruding portions 410 can be conductors having cuboidal shape, cylindrical shape or other geometrical shapes, and the openwork slots can have any geometrical shapes.
In the present embodiment, the protruding portions 410 and the openwork slots 420 are respectively arranged on the primary winding 401 and the secondary winding 402 in a single row. However, the arrangement of the protruding portions 401 of the primary winding 401 and the openwork slots 402 of the secodnary winding 402 is not limited to those described in the above embodiment. Those of ordinary skill in the art would appreciate that the protruding portions and the openwork slots may be arranged in a single row, double rows, multiple rows, or in other geometrical arrangements.
Though each of the protruding portions 410 extends into one of the openwork slots in one-to-one matter in the present embodiment, the implementation of the present invention should not be limited by this. A designer can make two or more protruding portions stretch into a same openwork slot.
Those skilled in the art can decide the turns, width and winding distance of the primary winding 401 and the secondary 402, and the outer diameter of the transformer 400 according to the practical requirements. To facilitate the comparison between the prior art and the present invention, the outer diameter of the transformer 400, the width and the winding distance are assumed 250um, 9um and 1.6um respectively. The number of the turns of the primary winding 401 and the secondary winding 402 is 2, and the first plane 400-1, the second plane 400-2 and the third plane 400-3 are respectively M6, M7 and M8. FIG. 6A illustrates the characteristic of the coupling factor k of the transformer 400 in FIG. 4D when the measured frequency is between 0˜20 GHz. FIG. 6B illustrates the characteristic of the coupling factor k of the transformer in FIG. 6A when the frequency is ranged between 0˜3.5 GHz. It can be seen from FIG. 6B that the coupling factor k is about 0.942 when the transformer 400 is at the working frequency 1 GHz. Compared with the conventional transformer 700 in FIG. 7, the coupling factor k has been significantly increased.
An example of the manufacturing method of the transformer 400 is illustrated below. First, a part of electrical path (as shown in FIG. 4C) of the primary winding 401 and a part of electrical path of the secondary winding 402 are substantially formed on the first plane 400-1 (as shown in FIG. 4C). A plurality of protruding portions 410 is formed on the electrical path of the primary winding 401 of the first plane 400-1, wherein each protruding portion 410 is electrically connected to the electrical path of the primary winding 401 of the first plane 400-1. In addition, vias 403 and 404 are formed at two ends of the electrical path of the secondary winding 402 of the first plane 400-1.
Next, a secondary winding 402 is substantially formed on the second plane 400-2 (as shown in FIG. 4B). Wherein, two turns of winding are formed by the electrical connection between vias 403 and 404 and the electrical paths of the secondary winding 402 of the second plane 400-2. A plurality of openwork slots 420 is formed. The protruding portions 410 penetrate the openwork slots 420, and the protruding portions are not electrically connected with the secondary winding 402.
Then, another part of electrical path of the primary winding 401 is substantially formed on the third plane 400-3 (as shown in FIG. 4A). The first winding 401 is formed by the electrical connection of the protruding portions 410 and the electrical path of the first plane 400-1 and the third plane 400-3.
In the application of a transformer, the coupling factor k is quite an important parameter in circuit design. A high k value means a high energy (or signal) conversion rate and means that the energy (or signal) loss of the transformer can be reduced. In the present invention, the protruding portions are formed between the primary winding and the secondary winding, so as to efficiently increase the coupling factor k of the transformer, thereby improving the energy (or signal) conversion rate and reducing energy (or signal) loss.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention 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 and their equivalents.
Patent Application
20080094166
