Broadband connection structure and method

A broadband connection structure is disclosed. The broadband connection structure includes a carrier and a chip. The carrier includes a first resonator. The chip includes a second resonator and configured on the carrier using a flip-chip method. The first resonator is connected to the second resonator via a magnetic field and an electric field existing therebetween to transmit a broadband signal between the carrier and the chip. A broadband connection method is also disclosed.

CROSS REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of Taiwan Patent Application No. 102140587, filed on Nov. 7, 2013, at the Taiwan Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

FIELD OF THE INVENTION

The present disclosure relates to a broadband connection structure, specifically to a broadband connection structure for connecting a chip and a carrier or a chip and another chip.

BACKGROUND OF THE INVENTION

Wire bonding is a conventional method of making connections between a chip and a carrier or a chip and another chip. However, a relatively high inductance of wire bonds will lead to bandwidth limitations for the signal transmissions. Therefore, wire bonding is commonly used in a structure that transmits low-frequency signals.

Please refer toFIG. 1, which is a schematic diagram showing a connection structure10in the prior art. The connection structure10includes chips104and106and material108, wherein the chip104is electrically connected to the chip106using a ribbon structure102. However, in this connection mode, the two chips must be at the same height and thus the additional material108is usually added under the thinner chip106in an additional step during the manufacturing process, which causes increased cost. Although the inductance of the ribbon structure102is lower than that of the wire bonds, for transmissions of high-frequency and broadband signals, the operable frequency range is still limited (e.g. less than 100 GHz) due to the high inductance of the ribbon structure102.

Please refer toFIG. 2, which is a schematic diagram showing a connection structure20in the prior art. The connection structure20includes a carrier204, a chip202stacked on the carrier204using a flip-chip method, and a connecting unit206, e.g. a bumper, configured on a connecting face208of the chip202. The connecting unit206is capable of connecting the chip202and the carrier204after being heated and pressed, and via which signals between the chip202and the carrier204can be transmitted. When the connecting unit206is a bumper, the large size thereof will cause a severe parasitic effect, and thus the operable bandwidth of signal transmissions between the chip202and the carrier204is limited.

Please refer toFIG. 3, which is a schematic diagram showing a connection structure30in the prior art. In the connection structure30, the chip and the carrier share the same substrate. The connection structure30includes connecting pads301and302, conducting wires303and304, equivalent loads305and306, and wire bonds307and308connecting the connecting pad301to the connecting pad302. Typically, the connecting pads301and302have a width of 200 μm, the conducting wires303and304have a length of 190 μm and a width of 100 μm, the wire bonds307and308have a width of 25 μm and a length of 32 μm, and the distance between the connecting pads301and302is about 225 μm. The equivalent loads305and306are preferably 50 ohm. In the connection structure30, the conducting wires303and304are used as equivalent inductors, and the connecting pads301and302are used as equivalent capacitors. The microwave circuit3012includes the equivalent load305, the conducting wire303and the connecting pad301. The microwave circuit3013includes the equivalent load306, the conducting wire304and the connecting pad302. The connection structure30can realize a low-pass filter of orders1through5and transmit signals between two microwave circuits3012and3013via the wire bonds307and308.

Unfortunately, such connection structure30has a large area and high cost, so it can be applied to neither signal transmission between two separate chips, nor that between an independent chip and an independent carrier. Furthermore, the connection structure30has the parasitic effect due to the difference between the ground potentials of the microwave circuit3012and3013, and thus the bandwidth for signal transmissions is limited.

Please refer toFIG. 4, which is a schematic diagram showing a package structure40for transmitting signals in the THz frequency band in the prior art. The package structure40includes a chip401and a waveguide403. The chip401includes a chip body4010and a dipole antenna402. In the package structure40, signals from the chip body4010can be radiated to the waveguide403via the dipole antenna402. The waveguide403can be further connected to other chips or carriers to transmit signals in the THz frequency band. Although the package structure40has a less insertion loss, the dipole antenna402on the chip body4010usually occupies a large area and thus causes an increase in cost. Due to the large volume of the waveguide403, which typically has a length L1 of about 1000 μm, a width W1 of about 600 μm and a height H1 of about 600 μm, the package structure40cannot be used to realize the miniaturized terahertz signal transmission system, and cannot be placed in handheld electronic products.

Please refer toFIG. 5, which is a schematic diagram of a transmission device50in the prior art. The transmission device50includes chips501,502and503and spacer layers504and505. The spacer layer504is located between chips501and502, and the spacer layer505is located between chips502and503. The chip501includes a transmitting circuit5011, a receiving circuit5012, a transmitting coil5013and a receiving coil5014on the top surface thereof as indicated inFIG. 5. Similarly, the chip502includes a transmitting circuit5021, a receiving circuit5022, a transmitting coil5023and a receiving coil5024, and the chip503includes a transmitting circuit5031, a receiving circuit5032, a transmitting coil5033and a receiving coil5034.

InFIG. 5, the transmitting coil5013and the receiving coil5024can convey digital signals via inductive coupling, and the digital signals are decoded in the receiving circuit5022. However, the high attenuation of the transmission device50in the intensity of the transmitted digital signals is unsuitable for applications using connection structures, and due to a relatively narrow range of data transmission bandwidth, signal transmissions in the THz frequency band or millimetric wave band cannot be achieved. Because of the high signal attenuation, the amplitude of the signals output by the transmitting circuit must be large enough to allow the receiving circuit to demodulate the digital signals correctly. Based on this aspect, the transmission device50uses both the transmitting circuit and the receiving circuit to effectively convey signals, but this has the disadvantages of high cost and high power consumption. Furthermore, the transmission device50has another disadvantage, the need of thinning the chips501,502and503, and thus an additional process is required. Based on the above, the high-cost transmission device50is not a good choice for transmissions between a chip and a carrier or between chips.

Please refer toFIG. 6, which is a schematic diagram showing a near field communication (NFC) system60in the prior art. The system60includes resonators601and602, wherein the resonator601includes a ring conductor6011and an equivalent capacitor6012, and the resonator602includes a ring conductor6021and an equivalent capacitor6022. The resonators601and602are separated by a distance D, which is generally at least larger than thousands of μm. Because the NFC system60transmits power using a near field method, the resonators601and602are required to have large quality factors, e.g. over 100, but it is hard to generate a high quality factor for the transmissions between a chip and a carrier or between chips. In addition, the NFC system60has a narrow operable bandwidth (tens of MHz) and a bulky size. Therefore, the NFC system60is not a good choice for transmissions between a chip and a carrier or between chips.

To overcome the problems mentioned above, a novel broadband connection structure and method are disclosed in the present disclosure after a lot of research, analysis and experiments by the inventors.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present disclosure, a broadband connection structure is disclosed. The broadband connection structure comprises a carrier and a chip. The carrier includes a first resonator, and the chip includes a second resonator and is configured on the carrier using a flip-chip method. The first resonator is connected to the second resonator via a magnetic field and an electric field existing therebetween to transmit a broadband signal between the carrier and the chip.

In accordance with another aspect of the present disclosure, a broadband connection structure is disclosed. The broadband connection structure includes a first chip including a first resonator and a second chip including a second resonator and placed on the first chip using a flip-chip method. The first resonator is coupled to the second resonator via a magnetic field and an electric field existing therebetween to transmit a broadband signal between the first chip and the second chip.

In accordance with a further aspect of the present disclosure, a broadband connection method is disclosed. The method includes steps of configuring a first resonator on a carrier and a second resonator on a chip, and forming a resonant coupling network via a magnetic coupling and an electric coupling between the first resonator and the second resonator to transmit a broadband signal between the carrier and the chip.

The above objectives and advantages of the present disclosure will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which:

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments in this disclosure are presented herein for the purposes of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.

Please refer toFIG. 7(a), which is a schematic diagram showing a connection structure72for a chip and a carrier according to a first preferred embodiment of the present disclosure. The connection structure72includes a carrier701and a chip702. The carrier701includes a first resonator7011, and the chip702includes a second resonator7021. The chip702is stacked on the carrier701using a flip-chip method to form a broadband connection structure70, as shown inFIG. 7(b). A broadband signal Sig1_In is input into the second resonator7021, and then a broadband signal Sig1_Out is output from the first resonator7011. Preferably, the broadband signals Sig1_In and Sig1_Out are differential signals.

Please refer toFIG. 7(b), which is a schematic diagram showing a broadband connection structure70according to the first preferred embodiment of the present disclosure. The chip702may be fixed to the carrier701by a connecting pad (not shown) on the carrier701and a solder ball on the chip702. After the chip702is flipped and fixed on the carrier701, the second resonator7021and the first resonator7011form a resonant coupling network703. The transmissions of the broadband signals Sig1_In and Sig1_Out are achieved by using magnetic field coupling of equivalent inductors, electric field coupling of equivalent capacitors and the resonant coupling network703, which will be detailed hereafter.

Please refer toFIG. 7(c), which is a schematic diagram showing an equivalent circuit of the broadband connection structure70inFIG. 7(b)according to the first preferred embodiment of the present disclosure. The chip702includes a load ZP, an equivalent inductor LPand an equivalent capacitor CP. The carrier701includes a load ZS, an equivalent inductor LSand an equivalent capacitor CS. The second resonator7021includes the equivalent inductor LPand the equivalent capacitor CP, and the first resonator7011includes the equivalent inductor LSand the equivalent capacitor CS. When the chip702is configured on the carrier701using a flip-chip method, the first resonator7011and the second resonator7021are separated by a gap to form an equivalent capacitor CCinFIG. 7(c). The equivalent capacitor CCuses an electric field formed between the chip702and the carrier701to couple the broadband signals Sig1_In and Sig1_Out. The equivalent inductors LPand LSuse a magnetic field formed between the chip702and the carrier701to couple the broadband signals Sig1_In and Sig1_Out.

Please refer toFIGS. 8(a) and 8(b), which are respectively a schematic diagram and a cross-sectional diagram showing a broadband connection structure74according to the first preferred embodiment of the present disclosure. The broadband connection structure70inFIG. 7(b)can be realized by the broadband connection structure74inFIG. 8(a). InFIGS. 8(a) and 8(b), the broadband connection structure74includes a carrier701and a chip702configured on the carrier701using a flip-chip method. The carrier701includes a first resonator7011, and the chip702includes a second resonator7021. The first resonator7011includes a first split-rectangular conducting wire741, which has a width WM1and a length LM1. The second resonator7021includes a second split-rectangular conducting wire742, which has a width WM2and a length LM2. The first split-rectangular conducting wire741and the second split-rectangular conducting wire742are concentric, split and referred to as “split rings” despite their rectangular shape. Specifically, although the first split-rectangular conducting wire741and the second split-rectangular conducting wire742are shaped like rectangles, they are not limited to that shape. There is a magnetic field and an electric field between the first resonator7011and the second resonator7021, through which the first resonator7011is coupled to the second resonator7021to form the resonant coupling network703to transmit the broadband signal Sig1_In or Sig1_Out between the carrier701and the chip702. The carrier701and the chip702are separated by a gap denoted as “Gap1” inFIG. 8(a). The distance of Gap1(DGAP1) is small enough to generate the magnetic field coupling and the electric field coupling between the chip702and the carrier701. Preferably, the distance DGAP1is about several μm to about tens μm.

InFIG. 8(a), the broadband signal Sig1_In is an alternating current (AC) signal, which may be composed of differential signals Sig1_In+ and Sig1_In−. The width WM1or the length LM1is preferably equal to or smaller than ⅕ of a wavelength λ1 to which a lowest frequency in the operable bandwidth corresponds. For example, the value of the width WM1or the length LM1is in a range of ⅕ to 1/10 of the wavelength λ1. Therefore, the size of either the first split-rectangular conducting wire741or the second split-rectangular conducting wire742is quite small, which will facilitate chip packaging for mobile devices. The common length of wire antennas transmitting signals via electromagnetic waves is equal to ½ or ¼ of the wavelength for the signal transmission to obtain optimal impedance matching. In the present disclosure, signals are transmitted by the magnetic field coupling and the electric field coupling, and the width WM1or the length LM1of the wire can be smaller than ⅕ of the wavelength of the signal transmission or even less. In this aspect, the package structure for the chip702is minimized because no large-sized antenna is integrated in the chip702. The first split-rectangular conducting wire741and the second split-rectangular conducting wire742may have other shapes, e.g. circular, elliptical or polygonal shapes. Preferably, they have the same and symmetric shape, which will be conducive for the chip702and the carrier701to have the same virtual ground potential. Similarly, the broadband signal Sig1_Out is an AC signal and may be composed of differential signals Sig1_Out+ and Sig1_Out−. The differential signals Sig1_In+ and Sig1_In− are input from Port2and pass through the resonant coupling network703, and afterward, the differential signals Sig1_Out+ and Sig1_Out− are output from Port1.

InFIG. 8(b), the chip702includes a substrate7022, a dielectric layer7023, a conducting layer7025and a passivation layer7024. Preferably, the conducting layer7025is a metal layer, which is usually a top metal layer in the semiconductor fabrication process. The passivation layer7024is used to prevent the surface of the conducting layer7025from a chemical reaction, which may corrode the chip702. Similarly, the carrier701includes a substrate7012, a dielectric layer7013, a conducting layer7015and a passivation layer7014. Preferably, the conducting layer7015is a metal layer. The passivation layer7014is used to prevent the carrier701from corrosion caused by a chemical reaction on the surfaces of the conducting layer7015. The metal layer7025includes the second split-rectangular conducting wire742forming the equivalent inductor LPThe metal layer7015includes the first split-rectangular conducting wire741forming the equivalent inductor LS. The equivalent inductor LPand the equivalent inductor LScouple the broadband signals Sig1_In and Sig1_Out via the magnetic field existing therebetween. The dielectric layers7013and7023include grounding pads705and706electrically connected to the end of the ground potential.

Please refer toFIGS. 8(a) and 8(b). The second split-rectangular conducting wire742, the insulating layer7023and the substrate7022form the equivalent capacitor CP. Alternatively, the chip702can use the parasitic capacitance of the second split-rectangular conducting wire742to form the equivalent capacitor CP. Similarly, the first split-rectangular conducting wire741, the insulating layer7013and the substrate7012form the equivalent capacitor CS. Alternatively, the equivalent capacitor CScan be formed from the parasitic capacitance of the first split-rectangular conducting wire741. The equivalent inductor LSand the equivalent capacitor CSare included in the first resonator7011, and the equivalent inductor LPand the equivalent capacitor CPare included in the second resonator7021. The first split-rectangular conducting wire741, the Gap1and the second split-rectangular conducting wire742constitute the equivalent capacitor CCto couple the broadband signals Sig1_In and Sig1_Out via the electric field.

InFIG. 8(a), the first split-rectangular conducting wire741has a symmetric shape and a symmetric conducting structure743, and the second split-rectangular conducting wire742has a symmetric shape and a symmetric conducting structure744as well. The differential signals Sig1_In+ and Sig1_In− are input to the symmetric conducting structure744and coupled to the symmetric conducting structure743via the magnetic field and the electric field, and finally the differential signals Sig1_Out+ and Sig1_Out− are output from the symmetric conducting structure743. Alternatively, the differential signals Sig1_In+ and Sig1_In− can be input to the symmetric conducting structure743and coupled to the symmetric conducting structure744via the magnetic field and the electric field, and finally the differential signals Sig1_Out+ and Sig1_Out− are output from the symmetric conducting structure744. The equivalent inductances VLP and VLS of the equivalent inductors LPand LSand the equivalent capacitance VC of the equivalent capacitor CCcan be adjusted to allow the operable bandwidth of this structure to cover the desired frequency band, such as the millimetric wave band or the THz frequency band. The equivalent inductance VLS can be adjusted by changing the width WM1and the length LM1of the first split-rectangular conducting wire741, and the equivalent inductance VLP can be adjusted by changing the width WM2and the length LM2of the second split-rectangular conducting wire742. The equivalent capacitance VC can be adjusted by changing the thickness TM1of the first split-rectangular conducting wire741and the thickness TM2of the second split-rectangular conducting wire742. The thickness TM1and the thickness TM2are associated with areas of two plates constituting the equivalent capacitor CC. One skilled in the art knows that the capacitance of parallel plate capacitors is given by C=∈×A÷d, where ∈ is permittivity of the dielectric between two parallel plates, A is the area of the plates, and d is the separation distance between the two parallel plates. Therefore, the equivalent capacitance VC of the equivalent capacitor CCcan be adjusted using the variables mentioned in the above equation. Because the broadband connection structure74does not realize a substantial connection to transmit the broadband signals Sig1_In and Sig1_Out, the chip702and the carrier701inFIG. 8(b)can be made of the same or different materials and do not need to share an identical substrate. That is, the substrate7012and the substrate7022inFIG. 8(b)may be made of the same or different materials, which increases flexibility in the fabrication process.

Please refer toFIG. 8(c), which is a schematic diagram showing a virtual ground plane745of the broadband connection structure74. The first split-rectangular conducting wire741includes a first symmetric portion747, and the second split-rectangular conducting wire742includes a second symmetric portion748. The virtual ground plane745is perpendicular to the first split-rectangular conducting wire741and the second split-rectangular conducting wire742. Each of the first symmetric portion747and the second symmetric portion748is symmetric with respect to the virtual ground plane745so that the carrier701and the chip702have an identical ground potential, which can prevent any parasitic effect generated between the carrier701and the chip702. Also, each of the symmetric conducting structures743and744is axially symmetric with respect to an axis746included in the virtual ground plane745. The first split-rectangular conducting wire741and the second split-rectangular conducting wire742are concentrically stacked and the stacked structure is symmetric with respect to an axis749. When the signal Sig1_In+ of the differential signals Sig1_In+ and Sig1_In− has a voltage of V1_In+, and the other signal Sig1_In− in the differential signals has a voltage of V1_In−, the ground potential formed on the virtual ground plane745is equal to V1_In+−V1_In−. Similarly, when the signal Sig1_Out+ in the differential signals Sig1_Out+ and Sig1_Out− has a voltage of V1_Out+, and the signal Sig1_Out− has a voltage of V1_Out−, the ground potential formed on the virtual ground plane745is equal to V1_Out+−V1_Out−. The voltages at turns7441and7442of the symmetric conducting structure744are respectively V2_In+ and V2_In−, which are different from the voltages V1_In+ and V1_In− due to the inductive effect. Because of the small Gap1(as shown inFIG. 8(a)), the voltages at the turns7441and7442have a tiny difference, which is small enough to be ignored, from those of portions of the first split-rectangular conducting wire741directly below the turns7441and7442. Therefore, for the second split-rectangular conducting wire741and the first split-rectangular conducting wire742, the voltage on the virtual ground plane745near the turns7441and7442and that on the virtual ground plane745near the portions of the first split-rectangular conducting wire741directly below the turns7441and7442can be considered an identical ground potential.

Please refer toFIG. 9, which is a schematic diagram showing scattering-parameters of the resonant coupling network703of the first preferred embodiment of the present disclosure. In this case, the defined bandwidth is in a range of 150 GHz to 250 GHz, while other operation frequency ranges can be realized as well by similar methods described in this disclosure. InFIG. 9, the horizontal axis shows the operation frequency in unit of GHz of the broadband signals Sig1_In and Sig1_Out. The vertical axis represents a return loss or gain of parameters S11, S22, S21and S12in unit of GHz, which are respectively denoted by rectangles, triangles, diamonds and circles. The parameters S11, S22, S21and S12respectively represent forward return loss, reverse return loss, forward gain and reverse gain of the resonant coupling network703.

InFIG. 9, the parameter S11is smaller than −25 dB in the frequency band BW1(about 150 GHz to 250 GHz), which means that when the broadband signal Sig1_In is input from Port2(as shown inFIG. 8(b)), the forward return loss generated in the frequency band BW1is low. Namely, during the transmission of the broadband signal Sig1_In in the frequency band BW1, the forward return loss is small. The parameter S21is larger than −1 dB in the frequency band BW2(about 140 GHz˜260 GHz), which means that when the broadband signal Sig1_In is input from Port2, the forward gain generated in the frequency band BW2is large. Namely, the energy loss is less than 1 dB after the broadband signal Sig1_In is transmitted from the chip702to the carrier701, which is particularly beneficial for the forward transmissions of the broadband signals Sig1_In and Sig1_Out. Similarly, the parameter S22is smaller than −25 dB in the frequency band BW1, which means that when the broadband signal Sig1_Out is input from Port1(as shown inFIG. 8(b), the reverse return loss in the frequency band BW1is low. Namely, during the transmission of the broadband signal Sig1_Out in the frequency band BW1, the reverse return loss is small. The parameter S12is larger than −1 dB in the frequency band BW2, which means that when the broadband signal Sig1_Out is input from Port1, the reverse gain generated in the frequency band BW2is large. The energy loss less than 1 dB after the transmission of the broadband signal Sig1_Out from the carrier701to the chip702is particularly beneficial for the reverse transmissions of the broadband signals Sig1_In and Sig1_Out. As shown inFIG. 9, preferred transmission properties can be obtained in the intersection region (about 150 GHz˜250 GHz) of the frequency bands BW1and BW2. Based on the above, it can be seen that bi-directional transmission of the broadband signals Sig1_In and Sig1_Out between the chip702and the carrier701has good transmission properties in the THz frequency band. One skilled in the art will be aware that the first preferred embodiment of the present disclosure used in the package of the chip702and the carrier701can be applied to the package of chips as well.

Please refer toFIG. 10(a), which is a schematic diagram showing the gain band of the resonant coupling network703of the present invention. InFIG. 10(a), the horizontal axis shows the operation frequency band of the resonant coupling network703, and the vertical axis shows the gain of the parameter S21, wherein ωLand ωHare two frequencies at the gain peaks, and ωminrepresents the frequency with the minimum gain between the two gain-peak frequencies ωLand ωH. Based onFIG. 10(a)illustrating features of the gain band of the forward gain, one skilled in the art will appreciate the features of the gain bands of reverse gains. The resonant coupling network703has a M-like signal gain band704, which includes two gain-peak frequencies ωLand ωH, and a frequency ωminbetween the two gain-peak frequencies ωLand ωHwith a gain lower than that at ωLor ωH. The M-like signal gain band704further includes a bandwidth BW3and a signal gain flatness Rflat1. The signal gain flatness Rflat1is determined by the gain difference between ωminand ωLand the gain difference between ωminand ωH.

Please refer toFIG. 7(c). The first resonator7011and the second resonator7021have a mutual inductance M1and a coupling capacitance CCexisting therebetween. The value of the mutual inductance M1is directly proportional to the length LM1and the width WM1of the first split-rectangular conducting wire741. Also, the value of the mutual inductance M1is directly proportional to the length LM2and the width WM2of the second split-rectangular conducting wire742. In addition, the value of the coupling capacitance CCis directly proportional to the thickness TM1of the first split-rectangular conducting wire741and the thickness TM2of the second split-rectangular conducting wire742. In addition, the length LM1and the width WM1of the first split-rectangular conducting wire741are directly proportional to the value of the equivalent inductor LS. Also, the length LM2and the width WM2of the second split-rectangular conducting wire742are directly proportional to the value of the equivalent inductor LP. In addition, the thickness TM1of the first split-rectangular conducting wire741is directly proportional to the capacitance of the equivalent capacitor CS, and the thickness TM2of the second split-rectangular conducting wire742is directly proportional to the capacitance of the equivalent capacitor CP. Please refer toFIGS. 7(c) and 10(a). The bandwidth BW3is associated with the mutual inductance M1and the coupling capacitance CC, and the signal gain flatness Rflat1is associated with a first quality factor parameter QLOADSof the first resonator7011or a second quality factor parameter QLOADPof the second resonator7021, where the parameter QLOADS=the capacitance of the equivalent capacitor CS×ω0×the impedance of the load ZS, the parameter QLOADP=the capacitance of the equivalent capacitor CP×ω0×the load ZP, QLOADS=QLOADP, and W0=1/((the inductance of the equivalent inductor LP×the capacitance of the equivalent capacitor CP)×(1−k2))1/2or ω0=1/((the inductance of the equivalent inductor LS×the capacitance of the equivalent capacitor CS)×(1−k2))1/2. The parameter k is a function of the mutual inductance M1and the coupling capacitance CC. Specifically, the parameter k is directly proportional to either the coupling capacitance CCor the mutual inductance M1. Based on the above, the mutual inductance M1can be adjusted by adjusting the widths WM1and WM2or the lengths LM1and LM2, and the coupling capacitance CCcan be adjusted by adjusting the thickness TM1of the first split-rectangular conducting wire741and the thickness TM2of the second split-rectangular conducting wire742.

Please refer toFIG. 10(b), which is a schematic diagram showing relationship between signal gain flatness Rflat1and parameter QLOADS. The horizontal axis shows the normalized operation frequency band of the resonant coupling network703. The vertical axis represents the normalized gain of the parameter S21. ωmindenotes the frequency with a minimum gain between the two gain-peak frequencies ωLand ωH. As shown inFIG. 10(b), the larger the parameter QLOADSis, the larger will be the slope of the curve between the two gain-peak frequencies ωLand ωH, which represents that the signal gain flatness Rflat1is not flat. A flat gain with a small gain variation is desired, and thus inFIG. 10(b), the parameter QLOADSis preferred to be 4.

Please refer toFIG. 10(c), which is a schematic diagram showing relationship between bandwidth and parameter k. The frequencies ωmin1, ωmin2and ωmin3respectively represent the frequencies with the minimum gains between two gain-peak frequencies ωL1and WH1, ωL2and ωH2, and ωL3and ωH3. The bandwidths between two gain-peak frequencies ωL1and ωH1, ωL2and ωH2, and ωL3and ωH3are BW3, BW4and BW5, respectively. With the increase of the parameter k from 0.3 to 0.5 to 0.7, the bandwidth is increased from BW4to BW3to BW5. The value of the parameter k can be increased by increasing the width WM1, the length LM1or the thickness TM1of the first split-rectangular conducting wire741or the width WM2, the length LM2or the thickness TM2of the second split-rectangular conducting wire742. However, it is preferred that the first and the second split-rectangular conducting wires have symmetric shapes to have a better effect of a common virtual ground. In order to have a wide range of bandwidth and a better gain property, the flatness of signals between ωL, ωHshould be stabilized. By using the adjustment manner above, the bandwidth and gain properties of the broadband signals Sig1_In and Sig1_Out can be optimized.

Specifically, in order to achieve good gain flatness of the M-like signals, while also maintaining a wide operation frequency band, the length LM1and the width WM1of the first split-rectangular conducting wire741and the length LM2and the width WM2of the second split-rectangular conducting wire742can be increased to increase the mutual inductance M1, and the coupling capacitance CCcan be increased by increasing the thickness TM1of the first split-rectangular conducting wire741and the thickness TM2of the second split-rectangular conducting wire742. The increase in the mutual inductance M1and the coupling capacitance CCwill cause an increase in the value of the parameter k, but will also cause an increase in the parameter QLOADSor QLOADS, which will lead to the degradation of the signal gain flatness Rflat1. Therefore, the parameters k, QLOADSand QLOADSshould be adjusted properly to obtain the optimal effect.

Please refer toFIG. 10(d), which is a schematic diagram showing the relationship among Rflat1, parameter k and parameter QLOADSor parameter QLOADP. The horizontal axis shows the parameter k, and the vertical axis represents either the parameter QLOADSor parameter QLOADP. The parameter Rflat1is a parameter that represents the signal gain flatness, i.e. the gain variation. Therefore, the parameter Rflat1with a small value indicates a small variation in gain and thus a flat gain. Based onFIG. 10(d), it can be seen that the parameter k is inversely proportional to either the parameter QLOADSor the parameter QLOADP.

When the broadband signals Sig1_In and Sig1_Out are in the frequency of hundreds of Gigahertz, the capacitor will have poor capacitance and even minor inductance. That is, such a capacitor has a low ratio of stored energy to consumed energy. In this case, an increase in the number of parallel capacitors is unlikely to generate better resonance characteristics. Therefore, the use of the parasitic capacitance inherent in the inductor itself as the capacitor connected to the inductor in the resonator can not only simplify the resonator structure, but is also favourable to the improvement of the resonance characteristic.

Please refer toFIG. 11(a), which is a schematic diagram showing a broadband connection structure80according to a second preferred embodiment of the present disclosure. The broadband connection structure80includes a chip801and a chip802, wherein the chip802is stacked on the chip801using a flip-chip method. The chip801includes a resonator803, and the chip802includes a resonator804, wherein there are a magnetic field and an electric field existing between the resonator803and the resonator804. Coupling between the resonator803and the resonator804can be realized by the magnetic field coupling and the electric field coupling so as to transmit a broadband signal Sig2_In or Sig2_Out between the chip801and the chip802. The broadband signal Sig2_In is an AC signal and composed of differential signals Sig2_In+ and Sig2_In−.

Please refer toFIG. 11(b), which is a sectional drawing of the broadband connection structure80inFIG. 11(a)with the flip-chip stack of chips. In the second preferred embodiment of the present disclosure, the broadband connection structure80is used to package the chip801and the chip802. One skilled in the art will appreciate that the broadband connection structure80can be used to package a chip and a carrier as well. The broadband connection structure80has an equivalent circuit similar to that shown inFIG. 7(7). Please refer toFIGS. 11(a), 11(b) and 7(c). The resonator803includes an equivalent inductor LSand an equivalent capacitor CS, and the resonator804includes an equivalent inductor LPand an equivalent capacitor CP. The equivalent inductor LSis formed from a transmission line83, which preferably is a microstrip. The transmission line83includes a conducting layer830, a dielectric layer833and a substrate832. The conducting layer830includes a conducting wire831serving as the equivalent inductor LS. A parasitic capacitance formed by the conducting wire831, the dielectric layer833and the substrate832acts as the equivalent capacitor CS. The equivalent inductor LPis formed from a transmission line84. The transmission line84includes a conducting layer840, a dielectric layer843and a substrate842. The conducting layer840includes a conducting wire841. The conducting wire841acts as the equivalent inductor LP. A parasitic capacitance formed by the conducting wire841, the dielectric layer843and the substrate842acts as the equivalent capacitor CP. The equivalent inductors LSand LPcouple the broadband signals Sig2_In and Sig2_Out through the magnetic field existing therebetween.

As shown inFIG. 11(b), there is a gap, denoted as “Gap2”, between the two chips801and802in the broadband connection structure80. The distance (DGAP2) of the Gap2between the conducting wires831and841is very small. The conducting wire831, the Gap2and the conducting wire841form the equivalent coupling capacitor CCand use the electric field to couple the broadband signals Sig2_In and Sig2_Out. The differential signals constituting the broadband signal Sig2_In are input into the transmission line84and then coupled to the transmission line83through the magnetic field and the electric field to output the differential signals constituting the broadband signal Sig2_Out. Alternatively, the differential signals constituting the broadband signal Sig2_In are input into the transmission line83and then coupled to the transmission line84through the magnetic field and the electric field to output the differential signals constituting the broadband signal Sig2_Out. The transmission line84and the transmission line83have similar symmetric shapes, which are symmetric with a virtual plane. A virtual ground is formed on the virtual plane, so that the chip801and the chip802have the same ground potential, which can prevent a parasitic effect from being generated between the chip801and the chip802.

InFIG. 11(b), the two transmission lines83and84form a resonant coupling network87. The substrates832and842may be directly and electrically connected to the ground potential end. Alternatively, the substrates832and842may be electrically connected to portions85and86of the chips, respectively, with the portions85and86electrically connected to the ground potential end. The conducting wire831has a length,831L, preferably equal to or smaller than ⅕, e.g. about ⅕˜ 1/10, of a wavelength to which a lowest frequency in the operable bandwidth of this structure corresponds. The width831W or the length831L of the conducting wire831will affect the coupling capacitance CC, and the length831L of the conducting wire831will affect the inductance VLS of the equivalent inductor LS. Similarly, the width841W or the length841L of the conducting wire841will affect the coupling capacitance CC, and the length841L of the conducting wire841will affect the inductance VLP of the equivalent inductor LPThe conducting wire831and the conducting wire841have a very small size and their projections completely overlap in a vertical direction.

In the second preferred embodiment, the resonant coupling network87has an equivalent circuit the same as that shown inFIG. 7(c), a M-like signal gain band the same as that shown inFIG. 10(a), relationships between signal gain flatness Rflat1and parameter QLOADSthe same as those shown inFIG. 10(b), and relationships between bandwidths of the broadband signals Sig2_In and Sig2_Out and parameter k the same as those shown inFIG. 10(c). Please refer toFIG. 11(b),FIGS. 10(a) to (c)andFIG. 7(c). The resonant coupling network87has an M-like signal gain band704, and the descriptions therefor are similar to the illustrations forFIG. 10(a)and thus are omitted here. The value of the coupling capacitance CCbetween the first resonator7011and the second resonator7021of the resonant coupling network87is directly proportional to the width831W of the conducting wire831and the width841W of the conducting wire841. The mutual inductance M1between the first resonator7011and the second resonator7021of the resonant coupling network87is directly proportional to the length831L and the length841L. Either the length831L or the length841L is directly proportional to the values of the equivalent inductors LSand LPEither the width831W or the width841W is directly proportional to the values of the equivalent capacitor CSand CP. The inductance of each of the equivalent inductors LSand LPcan be adjusted by adjusting the length831L of the conducting wire831and the length841L of the conducting wire841, and the capacitance of each of the equivalent capacitors CSand CPcan be adjusted by adjusting the widths831W and841W. The mutual inductance M1and the inductances of the equivalent inductors LSand LPare in direct proportion, and the capacitance of the coupling capacitance CCis directly proportional to the capacitances of the equivalent capacitors CSand CP. Based on the above, one skilled in the art can realize how to adjust the values of the mutual inductance M1and the coupling capacitance CCvia the sizes of the conducting wires831and841.

In order to achieve good gain flatness of the M-like signals, while maintaining a wide operation frequency band, the lengths831L and841L of the conducting wires831and841can be increased to increase the mutual inductance M1, and the widths831W and841W can also be increased to raise the coupling capacitance CC. The increase in the mutual inductance M1and the coupling capacitance CCwill cause an increase in the parameter QLOADSor parameter QLOADS, which will lead to a worse signal gain flatness Rflat1. However, the increase in the parameter QLOADSor QLOADS, i.e. a worse signal gain flatness, is conducive to forming two distinct operation frequencies so as to transmit different signals at two different frequencies.

Please refer toFIG. 12, which is a schematic diagram showing a method for transmitting a broadband signal according to the present disclosure. In step S101, a first resonator7011or803including a first magnetic field and a first conducting layer7015or830is provided. In addition, a second resonator7012or804including a second magnetic field and a second conducting layer7025or840is provided. In step S102, the two magnetic fields are coupled. In step S103, the two conducting layers7015/830and7025/840are coupled to generate an electric field for transmitting a broadband signal Sig1_In, Sig1_Out, Sig2_In or Sig2_Out.

Please refer toFIG. 13, which is a schematic diagram showing a broadband connection method according to the present disclosure. In step S201, a first resonator7011is configured on a carrier701, and a second resonator7021is configured on a chip702. In step S202, a broadband signal is provided to the first resonator7011or the second resonator7021. In step S203, a resonant coupling network703is formed by a magnetic coupling and an electric coupling between the first resonator7011and the second resonator7021to transmit a broadband signal Sig1_In or Sig1_Out between the carrier701and the chip702. In step S203, the method to generate the magnetic coupling and the electric coupling can be realized by flipping over the chip702to make its top side face down and then configuring the chip702on the carrier701.

Please refer toFIGS. 14(a) and 14(b), which are schematic diagrams respectively showing the magnetic field coupling and electric field coupling of a third preferred embodiment of the present disclosure. The transmitting device90used to transmit a broadband signal Sig3_In or Sig3_Out includes a first resonator901, a second resonator902and a device body94receiving the first resonator901and the second resonator902. The first resonator901includes a first magnetic field91and a first conducting layer903. The second resonator902being in communication connection with the first resonator901includes a second magnetic field92and a second conducting layer904. The first conducting layer903and the second conducting layer904couple to each other to form therebetween an electric field93, and the two magnetic fields91and92are coupled to each other to transmit the broadband signals Sig3_In and Sig3_Out.

The specific structure of the transmitting device90is the same as or similar to the first or second preferred embodiment of the present disclosure, as shown inFIGS. 8(a)-8(b)orFIG. 11(b), and has similar circuit features. As to how the shape or size of the conductors of the first and second conducting layers903and904affects the parameters k, QLOADSand QLOADP, and how the adjustments of the parameters k, QLOADSand QLOADPaffect the bandwidth of the broadband signals Sig3_In and Sig3_Out are described above and thus are omitted here.

Some embodiments of the present disclosure are described in the following.

1. A broadband connection structure comprises a carrier and a chip. The carrier includes a first resonator. The chip includes a second resonator and is configured on the carrier using a flip-chip method. The first resonator is connected to the second resonator via a magnetic field and an electric field existing therebetween to transmit a broadband signal between the carrier and the chip.

2. A broadband connection structure of Embodiment 1, wherein the first resonator includes a first equivalent inductor, and the carrier includes a first split-rectangular conducting wire constituting the first equivalent inductor; the second resonator includes a second equivalent inductor, and the chip further includes a second split-rectangular conducting wire constituting the second equivalent inductor; the first split-rectangular conducting wire has two first terminals, and the second split-rectangular conducting wire has two second terminals; and the broadband signal is a differential signal.

3. A broadband connection structure of any one of the above embodiments, wherein the first equivalent inductor and the second equivalent inductor couple the broadband signal via the magnetic field therebetween.

4. A broadband connection structure of any one of the above embodiments, wherein the differential signal is input to the first terminals, coupled to the second split-rectangular conducting wire via the magnetic field and the electric field and output from the second terminals.

5. A broadband connection structure of any one of the above embodiments, wherein the differential signal is input to the second terminals, coupled to the first split-rectangular conducting wire via the magnetic field and the electric field and output from the first terminals.

6. A broadband connection structure of any one of the above embodiments, further comprising: a virtual ground plane set between the first terminals and between the second terminals, and each of the first and second split-rectangular conducting wires is symmetric with respect to the virtual ground plane so that the carrier and the chip have an identical ground potential.

7. A broadband connection structure of any one of the above embodiments, wherein the first split-rectangular conducting wire has a length and a width, the broadband connection structure has an operable bandwidth, and one of the length and the width is less than one-fifth of a wavelength to which a lowest frequency in the operable bandwidth corresponds.

8. A broadband connection structure of any one of the above embodiments, wherein the carrier further includes a first substrate and a first insulating layer between the first substrate and the first split-rectangular conducting wire; the chip further includes a second substrate and a second insulating layer between the second substrate and the second split-rectangular conducting wire; and the first substrate and the second substrate are formed from one of an identical material and different materials.

9. A broadband connection structure of any one of the above embodiments, wherein the first resonator further includes a first equivalent capacitor formed from the first split-rectangular conducting wire, the first insulating layer and the first substrate; and the second resonator further includes a second equivalent capacitor formed from the second split-rectangular conducting wire, the second insulating layer and the second substrate constitute.

10. A broadband connection structure of any one of the above embodiments, wherein the first split-rectangular conducting wire has a first parasitic capacitance; the second split-rectangular conducting wire has a second parasitic capacitance; the first resonator further includes a first equivalent capacitor formed from the first parasitic capacitance; and the second resonator further includes a second equivalent capacitor formed from the second parasitic capacitance.

11. A broadband connection structure of any one of the above embodiments further comprises a gap between the carrier and the chip; and an equivalent coupling capacitor formed from the first split-rectangular conducting wire, the second split-rectangular conducting wire and the gap and coupling the broadband signal via the electric field.

12. A broadband connection structure of any one of the above embodiments further comprises a first chip including a first resonator; and a second chip including a second resonator and placed on the first chip by a flip-chip method, wherein the first resonator is coupled to the second resonator by a magnetic field and an electric field existing therebetween to transmit a broadband signal between the first chip and the second chip.

13. A broadband connection structure of Embodiment 12, wherein the first resonator includes a first equivalent inductor and a first equivalent capacitor, and the first chip further includes a first transmission line. The first transmission line includes a first conducting wire acting as the first equivalent inductor, a first substrate, and a first dielectric layer. The first chip has a first parasitic capacitance formed from the first conducting wire, the first dielectric layer and the first substrate and acting as the first equivalent capacitor.

14. A broadband connection structure of any one of Embodiments 12-13, wherein the second resonator includes a second equivalent inductor and a second equivalent capacitor. The second chip further includes a second transmission line, and the second transmission line includes a second conducting wire acting as the second equivalent inductor, a second substrate, and a second dielectric layer. The second chip has a second parasitic capacitance formed from the second conducting wire, the second dielectric layer and the second substrate and acting as the second equivalent capacitor.

15. A broadband connection structure of any one of Embodiments 12-14 further comprises a gap between the first and the second chips; and an equivalent coupling capacitor formed from the first conducting wire, the gap and the second conducting wire and coupling the broadband signal via the electric field.

16. A broadband connection structure of any one of Embodiments 12-15, wherein the first resonator having a first quality factor parameter is coupled to the second resonator having a second quality factor parameter to form a resonant coupling network; the resonant coupling network has an M-like signal gain band including a bandwidth and a signal gain flatness; the first resonator and the second resonator have a mutual inductance therebetween and a coupling capacitance; and the bandwidth is a function of the mutual inductance and the coupling capacitance, the signal gain flatness is a function of one of the first quality factor parameter and the second quality factor parameter.

17. A broadband connection method comprises steps of configuring a first resonator on a carrier and a second resonator on a chip and forming a resonant coupling network through a magnetic coupling and an electric coupling between the first resonator and the second resonator to transmit a broadband signal between the carrier and the chip.

18. A broadband connection method of Embodiment 17 further comprises steps of providing a first split-rectangular conducting wire on the carrier to act as a first equivalent inductor, and providing a second split-rectangular conducting wire on the chip to act as a second equivalent inductor, placing the chip on the carrier using a flip-chip method, and forming the magnetic coupling using the first equivalent inductor and the second equivalent inductor.

19. A broadband connection method of any one of Embodiments 17-18 further comprises steps of configuring a first conducting layer in the first resonator, configuring a second conducting layer in the second resonator, and coupling the first conducting layer and the second conducting layer to form an electric field.

20. A broadband connection method of any one of Embodiments 17-19, wherein the first resonator has a first magnetic field, and the second resonator has a second magnetic field. The method further comprises a step of coupling the first magnetic field and the second magnetic field.