WIRELESS COMMUNICATION DEVICE WITH ANTENNA ON PACKAGE
20200212536 ยท 2020-07-02
Inventors
Cpc classification
H01Q1/2283
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2221/68372
ELECTRICITY
H01L2224/08225
ELECTRICITY
H01L2224/97
ELECTRICITY
H01Q1/40
ELECTRICITY
H01L24/97
ELECTRICITY
H01L2224/95001
ELECTRICITY
H01L23/5389
ELECTRICITY
H01L21/568
ELECTRICITY
H01L2924/00012
ELECTRICITY
H01L2224/24155
ELECTRICITY
H01L24/25
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L2224/24137
ELECTRICITY
H01L2224/80
ELECTRICITY
H01L24/19
ELECTRICITY
H01L23/49816
ELECTRICITY
H01L24/96
ELECTRICITY
H01L21/481
ELECTRICITY
H01L2224/16235
ELECTRICITY
H01L2224/32225
ELECTRICITY
H01L2224/80
ELECTRICITY
H01L2224/04105
ELECTRICITY
H01L25/16
ELECTRICITY
H01L2221/68345
ELECTRICITY
H01L2224/97
ELECTRICITY
H01L2223/6677
ELECTRICITY
H01L23/49833
ELECTRICITY
H01L23/49827
ELECTRICITY
International classification
H01Q1/22
ELECTRICITY
H01L21/48
ELECTRICITY
H01L23/498
ELECTRICITY
Abstract
In a described example, a wireless communication device includes an antenna substrate having an antenna on an antenna side surface; a semiconductor die on an device side surface of the antenna substrate, opposite the antenna side surface; and an antenna protection layer covering the antenna and a portion of the antenna side surface of the antenna substrate having a uniform predetermined thickness across the antenna side surface of the antenna substrate within +/10%.
Claims
1. A wireless communication device, comprising: a substrate having an antenna on an antenna side surface; a semiconductor die on a device side surface of the substrate, opposite the antenna side surface; and an antenna protection layer covering the antenna and at least a portion of the antenna side surface of the substrate having a predetermined thickness across the antenna side surface of the substrate within +/10%.
2. The device of claim 1, wherein the antenna protection layer is deposited using ink jet deposition and the predetermined thickness of the antenna protection layer is in a range of 2 m to 20 m.
3. The device of claim 1, wherein a thickness of the antenna protection layer is in a range of 2 m to 100 m with a uniformity to within +/0.5 m.
4. The device of claim 1, wherein the predetermined thickness of the antenna protection layer is 2 m and is uniform to within +/0.2 m.
5. The device of claim 1, wherein the antenna protection layer is one selected from a group consisting essentially of: polyimide, polybenzoxazole, and epoxy.
6. The device of claim 1, and further comprising the substrate being a first substrate that is mounted to a second substrate.
7. The device of claim 6, wherein the first substrate is mounted to the second substrate by solder balls on the device side of the first substrate.
8. The device of claim 1 wherein the substrate is one selected from a group consisting essentially of: a molded interconnect substrate; a pre-molded lead frame with lead frame conductors and mold compound in a preformed structure; a tape based substrate carrying conductors; and film-based substrate carrying conductors; a laminate substrate with multiple layers of conductors and insulator layers; and a printed circuit board substrate of ceramic, fiberglass, epoxy or resin.
9. The device of claim 1, wherein the semiconductor die is a transceiver circuit coupled to the antenna by filled vias and traces on a multi-layer substrate.
10. A wireless communication device, comprising: an antenna coupled to a wireless communication circuit; and an antenna protection layer overlying the antenna with a thickness between 2 m and 20 m covering the antenna.
11. The wireless communication device of claim 10 wherein the antenna protection layer is deposited using ink jet deposition and a thickness of the antenna protection layer varies by less than +/.0.2 m.
12. The wireless communication device of claim 10 further comprising: the antenna over an antenna side surface of a substrate; and the substrate is one selected from a group consisting essentially of: a molded interconnect substrate; a pre-molded lead frame with lead frame conductors and mold compound in a preformed structure; a tape based substrate carrying conductors; a film-based substrate carrying conductors; a laminate substrate with multiple layers of conductors and insulator layers; and a printed circuit board substrate of ceramic, fiberglass, epoxy or resin.
13. The wireless communication device of claim 12 further comprising a transceiver semiconductor die mounted on a non-antenna side surface of the substrate that is opposite to the antenna side surface, the transceiver semiconductor die electrically coupled to the antenna.
14. The wireless communication device of claim 12 wherein the substrate is a first substrate and further comprising a second substrate, and the first substrate is mounted on the second substrate.
15. The wireless communication device of claim 14, wherein the first substrate is mounted on the second substrate with ball bonds.
16. The wireless communication device of claim 12, wherein the antenna protection layer is one selected from a group consisting essentially of: polyimide, polybenzoxazole, and epoxy.
17. A method for forming a wireless communication device, comprising: coating an antenna on an antenna side of a substrate strip with an antenna protection layer, where a thickness of the antenna protection layer is deposited to a predetermined thickness that is uniform to within +/10%; singulating antenna substrates from the substrate strip by cutting through saw streets between at least two antenna substrates on the substrate strip; and coupling the antenna on an antenna substrate to a wireless communication circuit.
18. The method of claim 17, further comprising: prior to singulating the antenna substrates, forming solder balls on electrical leads on a non-antenna side of the substrate strip that is opposite the antenna side of the substrate strip; mounting a singulated antenna substrate on a second substrate; and using the solder balls, forming ball bonds between the electrical leads on the non-antenna side of the antenna substrate and electrical leads on the second substrate.
19. The method of claim 18, further comprising mounting a semiconductor die on the non-antenna side of the antenna substrate and electrically coupling the semiconductor die to the antenna.
20. The method of claim 17, wherein coating an antenna further comprises performing ink jet deposition, and a thickness of the antenna protection layer is uniform to within +/0.2 m.
21. The method of claim 17, wherein coating an antenna further comprises performing screen deposition of an ink residue and a thickness of the antenna protection layer is in a range of 10 m to 20 m with a uniformity that is +/1 m.
22. The method of claim 17, wherein the antenna protection layer is one selected from a group consisting essentially of: polyimide, polybenzoxazole, and epoxy.
23. The method of claim 17, wherein after deposition, the antenna protection layer is cured at a temperature of 150 C.-200 C. for a time greater than zero to up to one hour.
24. The method of claim 17, wherein after deposition, the antenna protection layer is cured using exposure to light.
25. A wireless communication device, comprising: a semiconductor die having a circuit side on a device side surface of a redistribution layer; mold compound covering the semiconductor die on a non-circuit side and covering portions of the redistribution layer; first antenna conductors in the redistribution layer coupled to the semiconductor die; second antenna conductors over a surface of the mold compound facing away from the redistribution layer; and an antenna protection layer covering the second antenna conductors having a predetermined thickness across the second antenna conductors within +/10%.
26. The device of claim 25, wherein the antenna protection layer is deposited using ink jet deposition and the thickness of the antenna protection layer is in a range of 2 m to 20 m and is uniform to within +/0.2 m.
27. The device of claim 25, wherein a thickness of the antenna protection layer is in a range of 2 m to 100 m.
28. The device of claim 25, wherein a thickness of the antenna protection layer is in range of 2 m to 35 m.
29. The device of claim 25, wherein the antenna protection layer is selected from a group consisting essentially of: polyimide, polybenzoxazole, and epoxy.
30. The device of claim 25, wherein the semiconductor die is a transceiver circuit.
31. The device of claim 25, wherein the antenna protection layer is screen deposited and has a thickness in a range of 10 m to 20 m with a uniformity that is +/1 m.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0018] Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are not necessarily drawn to scale.
[0019] In this description, the term semiconductor die is used. As used herein, the term semiconductor die means a die formed using semiconductor material. Examples include dies containing integrated circuits, where several and sometimes hundreds or thousands of transistors are formed and are coupled together using patterned conductors to perform a desired function. An example function is a transceiver. Additional examples include dies including passive devices such as resistors, capacitors, inductors and diodes formed on a semiconductor substrate. Discrete devices such as one, or a few, power field effect transistors (FETs), bipolar junction transistors (BJTs), rectifiers, and amplifiers formed on semiconductor substrates are also examples of semiconductor dies. Analog-to-digital converters, RF filters, transceivers, photocells, photodiodes, digital micromirror devices (DMDs), and transformers are additional examples of semiconductor dies. As used herein, a packaged semiconductor device is a semiconductor die that has been mounted on a substrate with leads or terminals for making electrical connections, and which is wholly or partially covered by a protective package. In an example packaged semiconductor device, mold compound covers all or portions of the semiconductor die and leads coupled to the semiconductor die.
[0020] In this description, the term ink jet deposition is used for an example process of depositing material. As used herein, the term ink jet deposition means depositing material from a liquid in a reservoir that feeds a nozzle. Deposition is performed by forming drops in response to an electrical signal as the nozzle is moved with respect to a surface (or alternatively as the surface moves with respect to the nozzle). An ink jet deposition tool may have tens, hundreds or more nozzles. In a printing application, the material is ink, and the ink jet deposition process is referred to as ink jet printing. In deposition of materials in manufacturing, the liquid to be deposited can be referred to as ink and as used herein the term ink can include solder, dielectrics, conductive materials, adhesives, and polymers as used in the arrangements. Ink jet deposition allows precise placement of material by using drop on demand (DOD) technology, where a reservoir of the liquid has a nozzle, and a small volume of the liquid is forced from the nozzle in response to an electrical signal. The liquid forms a drop as it falls vertically onto a surface. In this description, the term ink residue is used. Ink residue is material deposited in liquid form by ink jet deposition or by screen deposition that may then be cured to form a solid layer, and the material is referred to herein as ink residue. The ink jet deposition in the arrangements can be used to deposit multiple layers so that a thin layer can be additively deposited over prior ink residue layers to form a thicker layer of material. The precision of the ink jet deposition tool allows deposition of the liquid material in some areas and not in others as the tool traverses across the surface (or if the tool is fixed, as the surface moves beneath the tool). The reservoir can include a piezo-electric actuator that expels a known volume of ink through a nozzle in response to an electrical signal, or in a thermal ink jet deposition tool, the liquid can be heated quickly by a resistive element in the reservoir and expand, forcing a known volume of liquid through the nozzle. The liquid forms drops that travel vertically to land on the surface that the material is deposited on. Because the material can be very accurately placed even in small areas, no etch or material removal step is needed to remove ink residue material after the ink jet deposition. Also, the material is used very efficiently with little waste when compared to spin coating, squeegee coating, screen deposition (sometimes referred to as screen printing) or slit print deposition processes.
[0021] In this description, the term predetermined thickness is used in reference to a deposited protection layer. As used herein, a predetermined thickness is a designed thickness for a layer. In this description, the term uniform predetermined thickness is used. As used herein, a uniform predetermined thickness is a designed thickness for a layer that varies only slightly, for example, a layer having a predetermined thickness that varies less than +/10% over the entire area of the layer is a layer with uniform predetermined thickness.
[0022] In the arrangements, the problem of antenna uniformity and control of antenna characteristics is solved by controlling thickness of an antenna protective layer deposited over antennas. In an example arrangement, the antenna protective layer is formed by ink jet deposition of an ink residue material. In another example arrangement, a screen deposition process leaves an ink residue layer as the antenna protective layer.
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[0024] In the wireless communication device 100 shown in
[0025] Solder balls 118 connect electrical leads 108 on the non-antenna side of the antenna substrate 102 to electrical leads 122 on a wireless communication system on second substrate 120 forming the wireless communication system 100. The second substrate 120 can be any of the substrate materials described hereinabove with respect to the antenna substrate, and can be a semiconductor wafer or portion thereof, or another semiconductor die. Because the semiconductor die 110 is carried on the underside of antenna substrate 102, the arrangement is sometimes referred to as a possum package for the semiconductor die 110. The semiconductor die 110 may be a wireless transceiver, transmitter, receiver or other wireless communication circuit.
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[0027] In the wireless communication device 200, a wireless communication module 207 is formed by a first set of ball bonds 218 that connects leads 208 on the non-antenna side of the antenna substrate 202 to leads 226 on a circuit substrate 224. In
[0028] In this wireless communication device 200, a second set of ball bonds 234, which can be solder balls or copper balls, pillars or bumps, electrically connects leads 232 on the non-antenna side of the circuit substrate module 207 to leads 222 on a wireless communication substrate 220, forming the wireless communications device 200.
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[0030] The performance of a wireless communication device or system is sensitive to the impedance matching between the antenna(s) and the transceiver circuits. One important component that impacts antenna impedance is an antenna protection layer. The antenna protection layer attenuates transmitted and received RF signals and reduces the antenna bandwidth. During design and development of the wireless communication system, the impedance of the communications system circuitry is matched to the impedance of the antenna. Any change in the thickness of the antenna protection layer from the target thickness changes the antenna bandwidth and, hence, degrades the performance of the wireless communication system. The change in thickness of the antenna protection layer between individual wireless communication systems over a manufacturing run can cause the performance distribution across the individual wireless communication systems in the manufacturing run to broaden. Wireless communications systems in the tail of the performance distribution can fail a performance specification, resulting in costly scrap. Further, variations in the thickness obtained between different manufacturing runs may require tuning after the systems are produced to create uniform performance within a specified performance criteria. Tuning adds costs to the manufacture of the systems.
[0031] In arrangements for wireless communication devices, the antenna protection layer is deposited with a thickness in the range of 2 m to 100 m and with a thickness variation of less than +/10%. While a thin layer is desireable, layers less than 2 ms may not be sufficient to protect the antennas and to form a controllable thickness. Layers greater than 100 ms will attenuate the signals, which is undesirable. A layer of thickness between 2 and 100 ms has sufficient thickness for the needed antenna protection and yet is thin enough to provide low signal attenuation. The arrangements herein provide for uniformity in the thickness of the layer, which is advantageous because devices produced by the arrangements will have the same performance, a requirement for efficient and low cost manufacture. An antenna protection layer with a thickness of 10 m or less is preferred for reduced negative impact on RF bandwidth. Other thicknesses in the range between 2 m to 100 ms can be used depending on materials chosen for the antenna protection layer.
[0032] Example methods of deposition that enable antenna protection films with thicknesses of 10 m or less and with thickness control of +/10% or less include screen deposition and ink jet deposition. When ink jet deposition is utilized, thickness variation in the ink residue deposited of less than +/0.2 ms can be achieved. Tightly controlled thickness variation narrows the distribution in performance across the individual wireless communication devices or systems produced within one manufacturing run and in between different manufacturing runs. This reduces scrap resulting from some of the wireless communication systems failing performance specifications.
[0033] The thinner antenna protection layer results in less signal attenuation. The thinner antenna protection layers obtained using the arrangements improve the performance of the wireless communication systems.
[0034] Example antenna protective layer materials useful with the arrangements include polyimide, polybenzoxazole (PBO), epoxies, resins, and solder mask or solder resist materials.
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[0038] In an example, a 5 m layer of antenna protection material was obtained by ink jet deposition of two layers. Each layer was targeted at approximately 2.4 m. In another example, a 10 m layer was obtained using ink jet deposition of four layers, with each layer targeted at approximately 2.4 m. In both examples the average thickness deviation over many samples was 0.2 m. Ink jet deposition deposits the antenna protection layer 316 very efficiently with little waste when compared to spin coating, squeegee coating, screen deposition or slit print deposition. In
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[0047] Each of the singulated wireless communication modules 507 can be mounted on a separate wireless system substrate 520 to form individual wireless communication devices 500. The variation in the thickness of the antenna protection layer 516 across the individual wireless communication systems 500 in a manufacturing run is less than 10%. This reduces the variation in performance between the wireless communication devices 500 in the manufacturing run and reduces the number of wireless communications devices 500 that would be otherwise scrapped because of failure to meet performance specifications.
[0048] In addition, the thickness of the antenna protection layer 516 on each of the wireless communications devices 500 can be 2 m or thicker. The thin antenna protection layer 516 provides less attenuation of the transmitted and received RF signals thus improving the performance of the wireless communication devices 500. Variation in the thickness of the antennal protection layer 516 of 10% or less provides narrow bandwidth spread across the wireless devices.
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[0061] In step 805 antenna conductors are formed over a surface of the redistribution layer. This is shown in
[0062] Modifications are possible in the described arrangements, and other alternative arrangements are possible within the scope of the claims.