Antenna-in-Package (AiP) Technology

Transcription

1 Forum for Electromagnetic Research Methods and Application Technologies (FERMAT) Antenna-in-Package (AiP) Technology by Y. P. Zhang, FIEEE Micro Radio Group Integrated System Research Lab School of Electrical and Electronic Engineering Nanyang Technological University (NTU) Singapore SLIDE 1/53

2 Abstract The antenna-in-package (AiP ) technology combines an antenna (or antennas) with a single-chip radio die into a standard surface mounted device symbolizing an innovative and important development in the miniaturization of wireless communications systems in recent years. The AiP technology is now the mainstream antenna technology and has been widely adopted by chip makers for 60 GHz radios. The slides focus on the development of the AiP technology in low-temperature cofired ceramic (LTCC) process for 60 GHz radios by Y. P. Zhang and his students and collaborators. *This use of this work is restricted solely for academic purposes. The author of this work owns the copyright and no reproduction in any form is permitted without written permission by the author.* SLIDE 2/53

3 Key Words Antenna: Discrete antenna, integrat ed antenna, and AiP; Package: Wire-bond package, flip-chip package; Circuit: Discrete circuit, integrated circuit; Chip: Packaged die, bare die; Process: LTCC, PCB, and CMOS. SLIDE 3/53

4 What is AiP Technology? AiP technology is an antenna solution technology that implements an antenna or antennas on (or in) an IC package that can carry a highlyintegrated radio or radar transceiver die (or dies). Antenna RF Transceiver Die SLIDE 4/53

5 Why AiP Technology? As compared with current chip antenna solution, AiP has better system performance, smaller system PCB area, lower system and assembly cost, and shorter time to market. Obviously, AiP offers an elegant antenna solution to single-chip radio or radar transceivers. Chip Antenna AiP SLIDE 5/53

6 How AiP Technology Evolved? Inspired from the similarity between ceramic patch antenna 1 and hermetic ceramic package 2, AiP 5-7 evolved from used ceramic package 3 through PCB mockup 4. SLIDE 6/53

7 Who Have Created Knowledge about AiP? SLIDE 7/53

8 Who Have Created Knowledge about AiP? SLIDE 8/53

9 Who Have Been Recognized for AiP Technology? SLIDE 9/53

10 Who Else Contributed to AiP Technology? Incomplete list of early AiP contributors FRACTUS PRC IMEC CUHK YONSEI IMST Insight SiP ITRI AMKOR FRACTUS SLIDE 10/53

11 Who Else Contributed to AiP Technology? Incomplete list of early AiP contributors NEC IBM Panasonic SLIDE 11/53

12 Who Developing AiP Technology Right Now? Incomplete list of current AiP developers IBM STM SAMSUNG Infineon SLIDE 12/53

13 Who Developing AiP Technology Right Now? Incomplete list of current AiP developers Hittite Panasonic NTT Intel Qualcomm Tensorcom IMEC SLIDE 13/53

14 AiP Technology It is now the mainstream antenna technology for 60 GHz. AiP for Rx AiP for Tx 10 mm SLIDE 14/53

15 AiP Design Codesign of antenna and package will maximize the AiP performance. Of course, it would be much better if chip could be also included in the design flow. Provisional Specification Package Antenna Can not meet specification 2D EM Simulation IE3D Design Released Meet specification 3D EM Simulation HFSS Meet specification Fig. 4. Design methodology. SLIDE 15/53

16 AiP Fabrication Low temperature cofired ceramic (LTCC) material and process are suitable for AiP mass production. Fig. 5. LTCC Fabrication Facilities (SIMTech). SLIDE 16/53

17 AiP Measurement Probe-based measurement setup is needed to measure an AiP and a balun for a differential signal operation. Z d 2Z o 1 S 2 11 S S S11 S (1) Wave guide twist Antenna under test & probe RL Z Z d c 20 (2) Zd Zc log10 where Z o = 50 W and Z c = 100 W. Antenna arm Motor Fig. 6. Measurement setup (IBM). SLIDE 17/53

18 Regulations for 60-GHz Radio Realized in 1995 that unlicensed use could be an appropriate regime for using such spectrum since most of the justifications for radio licensing were not applicable in these frequencies. Japan first issued 60-GHz regulation for unlicensed utilization in the 60-GHz band in the year of SLIDE 18/53

19 Standards for 60-GHz Radio WirelessHD ECMA IEEE c WiGig IEEE ad CWPAN Supports data transmission rates up to 7 Gbps. To encompass available but inconsistent unlicensed frequencies, the IEEE c standard divides nearly 9 GHz of spectrum from GHz into four 2.16-GHz channels. SLIDE 19/53

20 Package Technology Choices for 60-GHz Radio Technology Si-interposer /Through-Si-Via LTCC Laminate Interconnect Density Mechanical Stability Thermal Conductivity RF Loss Antenna Cost Maturity Si-interposers/ TSV Current efforts for 3D-integration don t address the needs of 60GHz. Low temperature co-fired ceramic (LTCC) technology is established for mm-wave applications. Laminate requires compromise / material development to provide better capability. Wire bonding possible and flip-chip bonding suitable for 60-GHz die attach. SLIDE 20/53

21 Antenna Type Choices for 60-GHz Radio Patch Pole Yagi Slot Grid Others Others: Silica, glass, quartz, ceramic, foam, polymer, resin and MEMS. Others: Lens, PIFA, IFA, cavity, horn, and waveguide antennas. Silicon LTCC III-V LCP PCB Others SLIDE 21/53

22 LTCC Material Properties LTCC Electrical Mechanical Thermal Conductor ε r tanδ MPa GPa ppm/k W/mK A6 M Au ACX NA NA 4.7 NA Cu Ag GL Ag GL Ag GL Cu GL Cu GL Cu SLIDE 22/53

23 LTCC Design Rules Substrate edge L 2 via E L 1 Inner pattern J M Q P H J O F G N B K C A W/B pads D Items Symbol Specification (Min in mm) W/B pad width A W/B pad width B Gap between W/B pads C Line width D Line to part pad spacing E Cavity to part pad spacing F Cavity to W/B pad spacing G Cavity to cavity spacing H Cavity to substrate edge J Line to line spacing K Cavity to line (surface) L Cavity to line (inner) L Via (d) pitch or to part edge M 2d W/B pad to line N Conner of cavity O W/B pad to via edge P Via edge to cavity edge Q SLIDE 23/53

24 0.15 mm LTCC Design Rules 0.2 mm = 0.35 mm 0.4 mm = 0.25 mm = 0.55 mm = 0.38 mm Au catch pad diameter 0.25 mm Au extension = 0.15 mm 0.35 mm Au W/B pad = 0.25 mm 0.25 mm W/B pad offset = 0.25 mm SLIDE 24/53

25 LTCC Tolerances Finished part dimensional tolerance is generally ± 0.7 % of part size but not less than ± 100μm for green cut parts. The shrinkage tolerance of circuit features in x and y direction is typically less than ± 0.1 % (production ± 0.2% typically). The minimum recommended substrate thickness is 500 μm. Layer thickness tolerance is ± 7 % (typically < ± 2% within manufacturing lot). The via hole punching to the tape sheet can be made typically to 10 μm accuracy in production. The layer-to-layer alignment accuracy for via and conductor is typically 10~20 μm. The screen printed conductor alignment error is typically 5~10 μm. The line width tolerance is typically 5%. Dielectric constant of 5.9 ± 0.2, loss tangent of ± 0.02%, and conductivity of S/m for A6M at 60 GHz. SLIDE 25/53

26 LTCC Roughness Conductor roughness Increase in conductor loss more than 2 times (experimentally demonstrated). Affects effective permittivity. Affects phase constant especially in thinner substrates Ceramic roughness Affects thickness (so impedance). Affects effective permittivity. SLIDE 26/53

27 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio Microstrip Patch Array Antenna Major advantages: Low profile, conformable to planar and non-planar surfaces, easy to design, simple to manufacture, compatible with both single-ended and differential silicon radio. Major disadvantages: Low efficiency, high Q, poor polarization purity, spurious feed radiation and very narrow impedance bandwidth. SLIDE 27/53

28 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Patch Array Antenna SLIDE 28/53

29 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Patch Array Antenna SLIDE 29/53

30 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio Microstrip Grid Array Antenna It was invented by Kraus in 1964, revived by Conti, et al in 1981, and studied by Nakano, et al at lower microwave frequencies. Major structural advantages: Low profile, conformable to planar and non-planar surfaces, easy to design, simple to manufacture, simple feeding network, compatible with both single-ended and differential silicon radio. Major operational advantages: High efficiency, high gain, good polarization purity, wide impedance and gain bandwidth, can be travelling-wave and able to beam steering by frequency shift, can be resonant with boresight beam radiation. SLIDE 30/53

31 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio Microstrip Grid Array Antenna Design Guidelines and Examples Choice of substrate: A thick substrate means using a low dielectric constant to limit the generation of surface waves. Number of loops: Given the specified gain G, the number of loops can be estimated by 2 10 (G-Gd)/10 where G d is the gain of microstrip halfwave dipole. Loop short side design: A short side is a radiating element. The length is required to be λ g /2 for resonance. The width sets the radiation resistance, which is governed by the desired amplitude taper on the array. Loop long side design: A long sideis a transmission line. The length is required to be λ g for resonance. The width sets the characteristic impedance, which should match the short side impedance. SLIDE 31/53

32 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 1 60 GHz in Ferro LTCC A6M l w Bandwidth = 7 GHz, efficiency > 80%, and maximum gain = 15 dbi Single Feed Design x v y v d a d v Number of meshes 14 Mesh dimensions l = 2.5 mm λg, w = mm λg/2 Substrate dimensions 13.5mm 8mm mm Line width and thickness 0.15mm and 0.01 mm Excitation location x v = 7.3 mm, y v = 3.98 mm Feeding dimensions d v = 0.1 mm, d a = 0.3mm SLIDE 32/53

33 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 1 Simulations show that large impedance bandwidth of 13 GHz 61.5 GHz), maximum gain of 15 dbi, and 3-dB gain bandwidth of 10 GHz are achieved mag(s11) (db) Peak Realized Gain (dbi) Frequency (GHz) Frequency (GHz) SLIDE 33/53

34 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 1 Simulations show that desirable patterns with low side lobe and week cross-polarization radiation are achieved. z x 300 y z = dB dB 60-20dB -30dB z = dB dB 60-20dB dB x 90-40dB 270 y 90-40dB Co Cross Co Cross SLIDE 34/53

35 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 1 SLIDE 35/53

36 mag(s 11 ) (db) Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example Measured Simulated Frequency (GHz) Peak gain (dbi) 5 Measured gain.7 0 Simulated gain Simulated efficiency Frequency (GHz) An excellent matching to a 50-Ω source achieved from GHz. The measured and calculated peak gain values are both 14.5 dbi with estimated efficiency better than 95% at 60-GHz. No de-embedding was made between the post-layout simulation and measurement Efficiency SLIDE 36/53

37 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 1 30 z 0 = 0 0dB z = 0 0 0dB dB -10dB 60-20dB dB dB -30dB x 90-40dB 270 y 90-40dB Measured, Co Measured, Cross Simulated, Co Simulated, Cross GHz 150 Measured, Co Measured, Cross Simulated, Co Simulated, Cross SLIDE 37/53

38 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 2 60 GHz in Ferro LTCC A6M l w Bandwidth = 7 GHz, efficiency > 80%, and maximum gain = 15 dbi Dual Feed Design Number of meshes 14 x v1 d a d v x v2 Mesh dimensions l = 2.5 mm λg, w = mm λg/2 Substrate dimensions 13.5mm 8mm mm y v y v Line width and thickness 0.15mm and 0.01 mm Excitation location x v1 = 4.57 mm, x v2 = 3.5 mm, y v = 3.98 mm Feeding dimensions d v = 0.1 mm, d a = 0.3mm SLIDE 38/53

39 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 2 Simulations show that large impedance bandwidth of 10 GHz 61.5 GHz) and maximum gain of 14 dbi for single-ended excitation and of 8 GHz 61.5 GHz) maximum gain of 16 dbi for differential excitation are achieved, respectively. Return loss (db) diff 30 single Frequency (GHz) Peak realized gain (dbi) diff single Frequency (GHz) SLIDE 39/53

40 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 2 Simulations show that differential excitation has narrower beamwidth in the E plane and similar beamwidth in the H plane than those of single-ended excitation z = x z y z = x 90-40dB 270 x 90-40dB dB -30dB 120 co, diff cross, diff co, single cross, single dB -10dB 0dB co, diff cross, diff co, single cross, single dB -10dB 0dB SLIDE 40/53

41 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 2 Solder balls M3 V d+ V d- M1 M2 M4 V s PCB board 60-GHz radio die PCB cavity SLIDE 41/53

42 Return loss (db) Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example Measured Simulated Frequency (GHz) Peak realized gain (dbi) Measured peak realized gain.7 0 Simulated peak realized gain Simulated efficiency Frequency (GHz) An excellent matching to a 50-Ω source achieved from GHz. The measured and calculated peak realized gain values agree well with estimated efficiency better than 95% at 60-GHz. No de-embedding was made between the post-layout simulation and measurement Efficiency SLIDE 42/53

43 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 2 30 z = 0 0 0dB z = 0 0 0dB dB -10dB 60-20dB dB dB -30dB x 90-40dB 270 x 90-40dB GHz SLIDE 43/53

44 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 3 60 GHz in Ferro LTCC A6M 3 4 Bandwidth = 7 GHz, efficiency > 80%, and gain 15 dbi over 7-GHz Number of meshes 32 Substrate dimensions 15mm 15mm 0.5 mm Linearly polarized SLIDE 44/53

45 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 3 SLIDE 45/53

46 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 3 S 11 (db) Pre simulation without signal traces Measured without signal traces Measured with signal traces Post simulation without signal traces Frequency (GHz) Peak realized gain (dbi) Pre simulation without signal traces Measured without signal traces Measured with signal traces Post simulation wihout signal traces Frequency (GHz) SLIDE 46/53

47 Array-Antenna-in-Package Design for Highly-Integrated 60-GHz Radio LTCC Microstrip Grid Array Antenna Design Example 3 60 GHz (a) 60 GHz (b) SLIDE 47/53

48 Concluding Remarks The AiP technology originated from Zhang s work has emerged as the most elegant antenna solution to modern radio systems. The AiP technology has been demonstrated for WLAN, UWB, and millimeterwave (60 GHz) radios, respectively. The AiP technology combines an antenna (or antennas) with a single-chip radio die into a standard surface mounted device symbolizing an innovative and important development in the miniaturization of wireless communications systems in recent years. SLIDE 48/53

49 Acknowledgement Zhang would like to acknowledge the contribution from his former students: Mr. Xue Yang, Mr. Lin Wei, Dr. Wang Junjun, Dr. Sun Mei, Dr. Zhang Bing and from his collaborators: Mr. Chua Kai Meng, Ms. Wai Lai Lai, and Dr. Albert Lu Chee Wai from Singapore Institute of Manufacturing Technology, Dr. Liu Duixian and Mr. Brain P. Gaucher from IBM T. J. Watson Research Center, USA, and Prof. C. Luxey, Dr D. Titz, and Dr. F. Ferrero from Université Nice Sophia- Antipolis, France in the development of AiP technology. SLIDE 49/53

50 References Y. P. Zhang, Integrated circuit ceramic ball grid array package antenna, IEEE Transactions on Antennas and Propagation, Vol. 52, No. 10, pp , October Y. P. Zhang, M. Sun, W. Lin, Novel antenna-in-package design in LTCC for single-chip RF transceivers, IEEE Transactions on Antennas and Propagation, vol. 56, no. 7, pp , July 2008 Y. P. Zhang, Enrichment of package antenna approach with dual feeds, guard ring, and fences of vias, IEEE Transactions on Advanced Packaging, vol. 32, no. 3, pp , August Y. P. Zhang, D. Liu, Antenna-on-chip and antenna-in-package solutions to highly-integrated millimeter-wave devices for wireless communications, IEEE Transactions on Antennas and Propagation, vol. 57, no. 10, pp , October Y. P. Zhang, M. Sun, K. M. Chua, L. L. Wai, D. Liu, Antenna-in-package design for wirebond interconnection to highly-integrated 60-GHz radios, IEEE Transactions on Antennas and Propagation, vol. 57, no. 10, pp , October SLIDE 50/53

51 References Y. P. Zhang, M. Sun, D. Liu, Y. L. Lu, Dual grid array antennas in a thin-profile package for flipchip interconnection to highly-integrated 60-GHz radios, IEEE Transactions on Antennas and Propagation, vol. 59, no. 4, pp , April D. Liu, Y. P. Zhang, Integration of array antenna in chip package for 60-GHz radios, Proceedings of the IEEE, vol. 100, no. 7, pp , July 2012 B. Zhang, Y. P. Zhang, D. Titz, F. Ferrero, C Luxey, A circularly-polarized array antenna using linearly-polarized sub grid arrays for highly-integrated 60-GHz radio, IEEE Transactions on Antennas and Propagation, vol. 61, no. 1, pp , January B. Zhang, D. Titz, F. Ferrero, C Luxey, Y. P. Zhang, Integration of quadruple linearly-polarized microstrip grid array antennas for 60-GHz antenna-in-package application, IEEE Transactions on Components, Packaging and Manufacturing Technology, vol. 3, no. 8, pp , August W. M. Zhang, Y. P. Zhang, M. Sun, C. Luxey, D. Titz, F. Ferrero, A 60-GHz circularly-polarized array antenna-in-package in LTCC technology, IEEE Transactions on Antennas and Propagation, vol. 61, no. 12, pp , December SLIDE 51/53

52 Biography Y. P. ZHANG is a Professor of Electronic Engineering with the School of Electrical and Electronic Engineering at Nanyang Technological University, Singapore. He serves as an Associate Editor of the IEEE Transactions on Antennas and Propagation. He received the S. A. Schelkunoff Transactions Prize Paper Award of the IEEE Antennas and Propagation Society (2012). He was the Chair, leading the Singapore Chapter to win the Best Chapter Award of the IEEE Antennas and Propagation Society (2013). He was the Advisor, guiding the Singapore Chapter to win the Outstanding Chapter Award of the IEEE Microwave Theory and Technique Society (2014). He was elevated as a Fellow of IEEE in 2009 for his contributions in subsurface radio and integrated antenna. SLIDE 52/53

53 Antenna Boy Questions and Comments to SLIDE 53/53