A transceiver frequency conversion module based on 3D micropackaging technology

The idea of Ku-band transceiver frequency conversion module design based on 3D micropackaging technology is proposed. By using the double frequency conversion technology,the dual transceiver circuit from Ku-band to L-band is realized by combining with the local oscillator and the power control circuit to complete functions such as amplification, filtering and gain. In order to achieve the performance optimization and a high level of integration of the Ku-band monolithic microwave integrated circuits(MMIC) operating chip, the 3 D vertical interconnection micro-assembly technology is used. By stacking solder balls on the printed circuit board(PCB), the technology decreases the volume of the original transceiver to a miniaturized module. The module has a good electromagnetic compatibility through special structure designs. This module has the characteristics of miniaturization, low power consumption and high density, which is suitable for popularization in practical application.

Design and characterization of a 3D encapsulation with silicon vias for radio frequency micro-electromechanical system resonator

In this paper, we present a three-dimensional（3D） vacuum packaging technique at a wafer level for a radio frequency micro-electromechanical system（RF MEMS） resonator, in which low-loss silicon vias is used to transmit RF signals.Au–Sn solder bonding is adopted to provide a vacuum encapsulation as well as electrical conductions. A RF model of the encapsulation cap is established to evaluate the parasitic effect of the packaging, which provides an effective design solution of 3D RF MEMS encapsulation. With the proposed packaging structure, the signal-to-background ratio（SBR） of 24 dB is achieved, as well as the quality factor（Q-factor） of the resonator increases from 8000 to 10400 after packaging.The packaged resonator has a linear frequency–temperature（ f –T） characteristic in a temperature range between 0℃ and 100℃. And the package shows favorable long-term stability of the Q-factor over 200 days, which indicates that the package has excellent hermeticity. Furthermore, the average shear strength is measured to be 43.58 MPa among 10 samples.

TXV Technology:The cornerstone of 3D system-in-packaging

System-in-packaging(Si P) can realize the integration and miniaturization of electronic devices and it is significant to continue Moore’s law.Through-X-via(TXV) technology is the cornerstone of 3 D-SiP,which enables the vertical stacking and electrical interconnection of electronic devices.TXV originated from through-hole(TH) in PCB substrates and evolved in different substrate materials,such as silicon,glass,ceramic,and polymer.This work provides a comprehensive review of four distinguishing TXV technologies(through silicon via(TSV),through glass via(TGV),through ceramic via(TCV),and through mold via(TMV)),including the fabrication mechanisms,processes,and applications.Every TXV technology has unique characteristics and owns particular processes and functions.The process methods,key technologies,application fields,and advantages and disadvantages of each TXV technology were discussed.The cutting-edge through-hole process and development direction were reviewed.

Ka-band broadband filtering packaging antenna based on through-glass vias (TGVs)

This work presents a novel design of Ka-band(33 GHz)filtering packaging antenna(FPA)that features broadband and great filtering response,and is based on glass packaging material and through-glass via(TGV)technologies.Compared to traditional packaging materials(printed circuit board,low temperature co-fired ceramic,Si,etc.),TGVs are more suitable for miniaturization(millimeter-wave three-dimensional(3D)packaging devices)and have superior microwave performance.Glass substrate can realize 3D high-density interconnection through bonding technology,while the coefficient of thermal expansion(CTE)matches that of silicon.Furthermore,the stacking of glass substrate enables high-density interconnections and is compatible with micro-electro-mechanical system technology.The proposed antenna radiation patch is composed of a patch antenna and a bandpass filter(BPF)whose reflection coefficients are almost complementary.The BPF unit has three pairs ofλg/4 slots(defect microstrip structure,DMS)and twoλg/2 U-shaped slots(defect ground structure,DGS).The proposed antenna achieves large bandwidth and high radiation efficiency,which may be related to the stacking of glass substrate and TGV feed.In addition,the introduction of four radiation nulls can effectively improve the suppression level in the stopband.To demonstrate the performance of the proposed design,a 33-GHz broadband filtering antenna is optimized,debugged,and measured.The antenna could achieve|S11|<-10 dB in 29.4‒36.4 GHz,and yield an impedance matching bandwidth up to 21.2%,with the stopband suppression level at higher than 16.5 dB.The measurement results of the proposed antenna are a realized gain of~6.5 dBi and radiation efficiency of~89%.

Solid–liquid Interdiffusion Bonding of Cu/Sn/Ni Micro-joints with the Assistance of Temperature Gradient

A novel solid-liquid interdiffusion(SLID)bonding method with the assistance of temperature gradient(TG)was carried out to bonding Cu and Ni substrates with Sn as interlayer.The element distribution and grain morphology of interfacial intermetallic compound(IMC)in Cu/Sn/Ni micro-joints during both SLID and TG-SLID bonding and in the final Cu/(Cu,Ni)_(6)Sn_(5)/Ni full IMC micro-joints were analyzed.Under the effect of Cu-Ni cross-interaction,interfacial(Cu,Ni)_(6)Sn_(5) dominated the IMC growth at all the interfaces.The morphology of the(Cu,Ni)_(6)Sn_(5) grains was closely related to Ni content with three levels of low,medium and high.The full IMC micro-joints consisted of L-(Cu,Ni)_(6) Sn_(5),M-(Cu,Ni)_(6)Sn_(5) and H-(Cu,Ni)_(6)Sn_(5) grains after SLID bonding or TG-SLID bonding with Ni as hot end,while only L-(Cu,Ni)_(6)Sn_(5) grains after TG-SLID bonding with Cu as hot end,showing that the direction of TG had a remarkably effect on the growth and morphology of the interfacial(Cu,Ni)_(6)Sn_(5) during TG-SLID bonding.Thermodynamic analysis revealed the key molar latent heat and critical Ni content between fine-rounded-like(Cu,Ni)_(6)Sn_(5) and block-like(Cu,Ni)_(6)Sn_(5) were 17,725.4 J and 11.0 at.%at 260℃,respectively.Moreover,the growth kinetic of the interfacial IMC was analyzed in detail during bonding with and without TG.Under the combination of TG and Cu-Ni cross-interaction,void-free full IMC micro-joints were fast formed by TG-SLID bonding with Cu as hot end.This bonding method may present a feasible solution to solve the problems of low formation efficiency and inevitable Cu_(3) Sn growth of full IMC joints for 3 D packaging applications.

Morphology and orientation evolution of Cu_(6)Sn_(5)grains on(001)Cu and(011)Cu single crystal substrates under temperature gradient

The morphology and orientation evolution of Cu_(6)Sn_(5)grains formed on(001)Cu and(011)Cu single crystal substrates under temperature gradient(TG)were investigated.The initial orientated prism-type Cu_(6)Sn_(5)grains transformed to non-orientated scallop-type after isothermal reflow.However,the Cu_(6)Sn_(5)grains with strong texture were revealed on cold end single crystal Cu substrates by imposing TG.The Cu_(6)Sn_(5)grains on(001)Cu grew along their c-axis parallel to the substrate and finally merged into one grain to form a fully IMC joint,while those on(011)Cu presented a strong texture and merged into a few dominant Cu_(6)Sn_(5)grains showing about 30°angle with the substrate.The merging between neighboring Cu_(6)Sn_(5)grain pair was attributed to the rapid grain growth and grain boundary migration.Accordingly,a model was put forward to describe the merging process.The different morphology and orientation evolutions of the Cu_(6)Sn_(5)grains on single crystal and polycrystal Cu substrates were revealed based on crystallographic relationship and Cu flux.The method for controlling the morphology and orientation of Cu_(6)Sn_(5)grains is really benefitial to solve the reliability problems caused by anisotropy in 3 D packaging.