Method for integrating antennas fabricated using planar processes
11349217 · 2022-05-31
Assignee
Inventors
- Jørgen Bøjer (Vadum, DK)
- Mikkel Baumann-Jorgensen (Aalborg, DK)
- Brian Skjold Bertelsen (Vadum, DK)
- Ulrik Riis Madsen (Aalborg, DK)
- Mathias Zacho Vestergaard (Terndrup, DK)
- Arthur S. Morris, III (Lakewood, CO, US)
Cpc classification
H01Q19/106
ELECTRICITY
H01Q19/104
ELECTRICITY
H01Q3/22
ELECTRICITY
H01Q9/0407
ELECTRICITY
H01Q19/13
ELECTRICITY
H01Q9/30
ELECTRICITY
H01Q19/32
ELECTRICITY
H01Q3/44
ELECTRICITY
International classification
H01Q9/30
ELECTRICITY
H01Q19/13
ELECTRICITY
H01Q3/26
ELECTRICITY
H01Q3/22
ELECTRICITY
Abstract
Methods and devices for integrating antennas fabricated using planar laminate processes. The method includes laminating one or more conductive layers to a first dielectric material layer, forming one or more holes through at least the first dielectric material layer, forming a monopole antenna through at least a first of the holes, attaching one or more integrated circuit dies to one of the conductive layer, and connecting the integrated circuit dies to the monopole antenna. The device can include a planar laminate integrated circuit module including one or more dielectric material layers, one or more integrated circuit die on a surface of or attached to the planar laminate integrated circuit module, and an integrated monopole antenna interfaced with the integrated circuit dies. The integrated monopole antenna is formed in a through hole of the planar laminate integrated circuit module, the through hole being formed through at least one of the dielectric material layers.
Claims
1. A method for fabricating an integrated monopole antenna in a planar laminate module, the method comprising: laminating one or more conductive layers to a first dielectric material layer; forming one or more holes through at least the first dielectric material layer; forming a monopole antenna within at least a first of the one or more holes; attaching one or more integrated circuit dies to one of the one or more conductive layers; and connecting the one or more integrated circuit dies to the monopole antenna.
2. The method of claim 1 further comprising etching one or more patterns into the one or more conductive layers.
3. The method of claim 1 further comprising laminating one or more outer dielectric material layers onto and around a surface of the one or more conductive layers on the first dielectric material layer.
4. The method of claim 1, wherein forming the one or more holes comprises: etching and patterning a top layer of the planar laminate module to form one or more annular rings, each having a diameter that is greater than a diameter of the monopole antenna; and drilling a hole through each of the one or more annular rings to a desired depth in the planar laminate module.
5. The method of claim 1, wherein forming the monopole antenna comprises plating an inner surface of the first of the one or more holes.
6. The method of claim 5, wherein the method further comprises filling each of the one or more holes with a filling material.
7. The method of claim 5 further comprising using an electroless plating process for plating the one or more holes.
8. The method of claim 1, wherein a length of the monopole antenna is equal to about one-quarter of a wavelength of a desired operating or resonance frequency of the monopole antenna.
9. The method of claim 1 further comprising positioning a reflector near the monopole antenna, the reflector being configured to reflect radiation emitted from the monopole antenna.
10. The method of claim 9 further comprising drilling a slot configured such that the reflector can be in the slot.
11. The method of claim 1 further comprising machining a cavity in the planar laminate module configured such that the one or more integrated circuit dies can be integrated to the planar laminate module.
12. The method of claim 1 wherein the monopole antenna is connected to radio circuitry in the one or more integrated circuit dies.
13. The method of claim 12 wherein the radio circuitry includes circuitry configured to tune the monopole antenna to operate at different frequencies or different frequency bands.
14. The method of claim 12 further comprising forming one or more additional antenna elements through at least a second of the one or more holes.
15. The method of claim 14 wherein the one or more additional antenna elements are connected to impedance tuning circuitry or switching elements in the one or more integrated circuit dies.
16. A planar laminate integrated circuit module comprising: one or more dielectric material layers; one or more integrated circuit die on a surface of or attached to the planar laminate integrated circuit module; and an integrated monopole antenna interfaced with the one or more integrated circuit dies; wherein the integrated monopole antenna is formed within a through hole of the planar laminate integrated circuit module, the through hole being formed through at least one of the one or more dielectric material layers.
17. The planar laminate integrated circuit module of claim 16 wherein pads of the one or more integrated circuit dies are wire bonded to pads of the surface of the planar laminate integrated circuit module.
18. The planar laminate integrated circuit module of claim 16 wherein an inner surface of the through hole is plated.
19. The planar laminate integrated circuit module of claim 18 wherein the through hole is plated using electroless plating.
20. The planar laminate integrated circuit module of claim 19 wherein the through hole comprises a filling material.
21. The planar laminate integrated circuit module of claim 16 wherein the integrated monopole antenna has a dimension that is equal to approximately one-quarter wavelength of an operating or resonating frequency of the integrated monopole antenna.
22. The planar laminate integrated circuit module of claim 16 wherein the integrated monopole antenna is connected to radio circuitry in one of the one or more integrated circuit dies.
23. The planar laminate integrated circuit module of claim 22 wherein the radio circuitry comprises circuitry configured to tune the monopole antenna to operate at different frequencies or different frequency bands.
24. The planar laminate integrated circuit module of claim 22 further comprising one or more additional integrated antenna elements formed in respective through holes of the planar laminate integrated circuit module.
25. The planar laminate integrated circuit module of claim 24 wherein the one or more additional integrated antenna elements are connected to impedance tuning circuitry or switching elements in one of the one or more integrated circuit dies.
26. The planar laminate integrated circuit module of claim 16 further comprising one or more reflector configured to reflect radiation from the integrated monopole antenna away from the one or more reflector.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The features and advantages of the present subject matter will be more readily understood from the following detailed description which should be read in conjunction with the accompanying drawings that are given merely by way of explanatory and non-limiting example, and in which:
(2)
(3)
(4)
(5)
DETAILED DESCRIPTION
(6) The present subject matter provides methods for, and devices formed by, fabricating an integrated monopole antenna in a planar laminate processed module. In one aspect, the present subject matter provides a method of fabricating an integrated monopole antenna in a planar laminate processed module.
(7) Referring to
(8) Referring next to
(9) Next, as illustrated by
(10) As a hypothetical example, given a radio wave at a frequency of about 28 GHz and the module 100 surrounding the integrated monopole 106 having a relative permittivity of ε.sub.r=3, the wavelength (λ) of the signal would be about 6.18 mm.
λ=v/f v=velocity of the radio signal, f=frequency
v=c/√{square root over (ε)} c=speed of light through vacuum (i.e. 2.998×10.sup.8 m/s); and ε is the relative permittivity of the medium
v=(2.998×10.sup.8)/√{square root over (3)}=1.7308×10.sup.8 m/s
λ=(1.7308×10.sup.8 m/s)/28×10.sup.9 Hz λ=6.18 mm
Throughout the remainder of the description herein, the hypothetical described above will be used to demonstrate the wavelength values of the dimensions of some of the devices described herein. However, those having ordinary skill in the art will appreciate that, by changing the medium surrounding the monopole (i.e. to free space or a medium having a relative permittivity of ε.sub.r=1) the adjusted wavelength, and thus the length of the monopole, will change according to the formulations described above.
(11) Those having ordinary skill in the art will appreciate that as the relative permittivity of the surrounding space changes, so would the wavelength. Thus, in this hypothetical, the length of the integrated monopole 106, at ¼ wavelength, would be about 1.5 mm (i.e., 0.25*6.18 mm). In some embodiments, the layer that includes the top layer 102 can be etched and patterned to include an annular ring, where a hole for the integrated monopole 106 can be drilled or otherwise formed, wherein the annular ring is a circular conductive ring on the surface of the top layer 102 that has a diameter that is greater than the planned diameter of the hole for the integrated monopole 106. Those having ordinary skill in the art will appreciate that adding the annular ring will increase the effective length of the integrated monopole 106 so that the integrated monopole 106 can be shorter for a given frequency of operation.
(12) As illustrated in
(13) In some embodiments, the conductive foil 204 will need to be etched away so as to allow the integrated monopole 106 to operate properly. For example, as indicated in
(14) Referring next to
(15) Following the plating process a mechanical hole is left behind that is the center of the integrated monopole 106. In some embodiments, the mechanical hole can be filled with a filling material (i.e., an underfill) configured to help absorb mechanical stress from solder connections. If the mechanical hole is not filled prior to mounting the module, an air cavity will remain in the module encapsulated by the underfill material. An air cavity can stress the connection as the air (or air and moisture) will expand during heating. Alternatively, a hole near a solder connection can make the solder connection unreliable if solder material floods into the hole. In some embodiments, dielectric loading of the integrated monopole 106 is required, in which case, a layer of dielectric (i.e., a dielectric loading layer) can be laminated over the monopole end side of the integrated monopole 106.
(16) As described above with respect to
(17) As illustrated in
(18) Although the above embodiments illustrate a core dielectric layer 202 as the layer of the module 100 where the top copper foil layer is placed, those having ordinary skill in the art will appreciate that although core dielectric layers 202 and prepreg layers 206 are shown in this particular figure, the dielectric layers used in this procedure could be either core dielectric layers or prepreg layers or any other suitable dielectric layer. With that being said the core layers 202 will have much tighter thickness tolerances and thus, should be used for critical vertical dimensions. Any valid PCB sequence is acceptable, the key is to ensure the appropriate thickness for the monopole antenna 106. The exact sequence in which the prepreg 206 or core layers 202 are layered is also not as important, the key is to use a mixture of dielectric layers to achieve the desired thickness based on the most efficient way to build the module 100.
(19) As described above with respect to
(20) It should be noted that the subject matter of the present disclosure is configured such that the inner-shield layer (i.e., the core dielectric layer 202 closest to the top layer 102) in
(21) Referring next to
(22) In some embodiments, as shown in
(23) In some other embodiments, the integrated circuit die 108 can be casted into or molded together with the module 100. In such an embodiment, the integrated circuit die 108 is placed on the top layer 102 (i.e. on the laminate) or in the cavity 112 and casted or molded into/together with the module 108. From there, conductive traces can be plated between the laminate interconnect traces and the integrated circuit die 108 pads using integrated processes. Those having ordinary skill in the art will appreciate that various other steps in the process can be incorporated into the steps described above. Additionally, those having ordinary skill in the art will appreciate that the integration of the chip can be performed where the chip is “flip-chipped” onto/into the module or where the module is formed around an embedded chip. In some other embodiments, the integration of the chip can be performed using wafer level packaging processes.
(24) Referring next to
(25) Depending on the aspects and positioning of the reflector 110, it can be used to further steer or direct the radio signals from the integrated antenna 106 away from the reflector 110. Moreover, as shown in
(26) Referring next to
(27) In some embodiments, the third step 406 in the process comprises laminating further dielectric layers and conductive foil layers (inner layers) onto the core conductive material layers. In some embodiments, the fourth step 408 in the process comprises etching the now outer conductive layer patterns according to previous steps described above. If the inner layer is an interconnect layer to the integrated monopole antenna the layer pattern can have a remaining conductive trace from the antenna towards the transmitter or receiver circuit as well as a ring, such as, for example and without limitation, an annular ring or similar pattern used in the later plating process for the integrated monopole antenna. If the inner layer is used as a ground reference for the integrated monopole antenna the ground pattern will have a hole in the area where the antenna cylinder can be drilled. In some embodiments, the fifth step 410 in the process comprises laminating further dielectric layers and conductive foil layers (outer layers) onto and around a surface of the inner layers and the core dielectric material layers until the desired thickness from the integrated antenna monopole end to the selected ground plane is achieved. In some embodiments, the length of the monopole can be about a quarter wavelength of an operating or resonating frequency of the integrated monopole antenna.
(28) For example and without limitation, the hypothetical described above, where the operating frequency of the monopole antenna is about 28 GHz, the desired length of the monopole antenna would be about 1.5 mm (i.e., assuming the material surrounding the monopole antenna is a material with a relative permittivity of ε.sub.r=3).
(29) As a different hypothetical, say for example, the operating frequency is about 10 GHz. In such a hypothetical, the wavelength of the signals would be about 1.7 cm and a quarter of that wavelength would be about 4.3 mm. Those having ordinary skill in the art will appreciate that the thickness of the layers and the length of the monopole antenna will range based on the operating frequency of the monopole antenna. In some embodiments, the dielectric layers can be either prepreg layers or core dielectric layers depending on the manufacturing preferences associated with a particular module being developed.
(30) In some embodiments, the sixth step 412 in the process comprises forming (i.e., etching and/or patterning) annular ring, one or more annular rings, or other similar pattern, in the outer layers (i.e., through the dielectric material layers) of the module. In some embodiments, each of the annular rings is formed with a diameter larger than the intended diameter for the integrated monopole antenna and can be used for the plating process. Next, in some embodiments, the seventh step 414 in the process comprises forming a hole, or one or more holes, having a location and diameter of the integrated monopole antenna within the annular ring(s). In some embodiments, the hole can be formed by drilling or other suitable methods. Once the hole has been formed in the annular ring, the eighth step 416 in the process comprises plating the drilled hole to form an antenna monopole. In some embodiments, the hole can be plated using procedures known to those having ordinary skill in the art. For example and without limitation, the hole can be plated using an electroless plating process. Once the hole is plated, in some embodiments, the ninth step 418 in the process can comprise filling the drilled and plated hole with a filling material as described above (i.e., underfill). In some embodiments, the process of the present disclosure can comprise a tenth step 420 comprising optionally laminating a dielectric loading layer to the monopole end side of the integrated monopole antenna. However, the tenth step 420 is usually only performed if dielectric loading of the antenna monopole is required. In some embodiments, a reflector is needed for the module, in which case the process of the present disclosure can comprise an eleventh step 422 comprising optionally forming (i.e., drilling) a slot in the outer layers for a reflector to be included. Additionally, in this same vein, a twelfth step 424 comprising optionally plating the reflector in the slot can be performed in order to form the reflector after the slot has been formed (i.e., drilled). In some embodiments, the reflector can be plated using any technique known to those having ordinary skill in the art. For example and without limitation, in some embodiments, the reflector can be plated using edge plating processes.
(31) Once the layers of dielectric material have been finished and the antenna(s) have been formed and plated, in some embodiments, the thirteenth step 426 in the process comprises machining a cavity, or one or more cavities, in the top layer of the laminate (i.e., conductive layers) for integrating an integrated circuit die, or one or more integrated circuit dies, to the module. Once the cavity is machined, those having ordinary skill in the art will appreciate that any number of techniques can be utilized to attach or otherwise bond the integrated circuit die to the module. In some embodiments, for example and without limitation, the integrated circuit die is wire bonded to the module. In such a process, the fourteenth step 428A comprises attaching the integrated circuit die to the machined cavity in the laminate. Next, the fifteenth step 430A in the process comprises wire bonding the integrated circuit die to the module using conductive wires (i.e., short wedge-to-wedge wire bonds where the laminate bond pads and the integrated circuit die pads are at the same level) to connect the laminate bond pads to the integrated circuit die pads. This allows the integrated circuit die to interface with the monopole antenna.
(32) In some other embodiments, the integrated circuit die is casted into or molded together with the module. In such a process, the fourteenth step 428B comprises placing the integrated circuit die on the laminate or in the laminate cavity and casting the die into or molding the die together with the module. Finally, the fifteenth step 430B in the process comprises plating conductive traces between the laminate interconnect traces and the integrated circuit die pads using integrated processes known to those having ordinary skill in the art. In some embodiments, the interconnect traces are on the top layer or surface of the module. In such an embodiment, in some case, one or more other layer of dielectric material can be applied to protect the interconnects and form pads.
(33) More than one antenna can be produced using the above methods. In other words, multiple annular rings can be formed and drilled, and each of those drilled rings can be plated and filled as well. In some embodiments, the method further comprises forming two more additional antenna elements through at least a second and a third of the one or more holes drilled. In such an embodiment, a first monopole antenna element drilled and formed in steps 412 through 418, can be connected to radio circuitry in the one or more integrated circuit dies. The radio circuit can include circuitry configured to tune the monopole antenna to operate at different frequencies or different frequency bands. Additionally, antenna elements formed in the second and third of the holes drilled can be connected to impedance tuning circuitry or switching elements in the one or more integrated circuit dies.
(34) The present subject matter can be embodied in other forms without departure from the spirit and essential characteristics thereof. The embodiments described therefore are to be considered in all respects as illustrative and not restrictive. Although the present subject matter has been described in terms of certain specific embodiments, other embodiments that are apparent to those of ordinary skill in the art are also within the scope of the present subject matter.