Antenna device, communication device, and imaging system

Abstract

To provide a suitable antenna device having a plurality of substrates.SOLUTION: An antenna device includes: a first substrate which includes an antenna array provided with a plurality of active antennas each including a semiconductor structure for generating or detecting electromagnetic waves and an antenna, and a wiring line electrically connected to the plurality of active antennas; and a second substrate which is laminated with the first substrate and includes a control circuit of the antenna array. The first substrate and the second substrate are bonded by a bonding surface. The control circuit is electrically connected to the antenna array via the wiring line. The control circuit of the second substrate controls operations of the plurality of active antennas of the first substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an antenna device, a communication device, and an imaging system.

Background Art

[0002] In recent years, due to being in the frequency band of the next-generation communication standard 6G, the development of semiconductor devices that output or detect electromagnetic waves such as terahertz waves has been accelerating. An active antenna integrating a resonant tunneling diode (RTD) and an antenna is expected as a high-frequency element that operates at room temperature in the frequency region near 1 THz. Patent Document 1 discloses an active antenna array for terahertz waves using an RTD. Such high-frequency elements are formed on a semiconductor substrate such as InP (indium phosphide) using materials such as InGaAs (indium gallium arsenide) with high electron mobility. On the other hand, the control circuit of the high-frequency element is formed on a semiconductor substrate using a semiconductor material such as Si (silicon).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the substrate on which high-frequency elements are formed and the substrate on which the control circuit is formed are different types of substrates, it becomes necessary to manufacture each substrate individually. In this case, depending on the connection method between the substrate on which the high-frequency elements and the substrate on which the control circuit is formed, signal delay or signal loss may occur due to inductance caused by the wiring length, making high-speed signal control impossible. In addition, depending on the connection, the degree of freedom of control of the antenna array may be reduced. In other words, in antenna devices having a substrate on which high-frequency elements are formed and a substrate on which the control circuit is formed, detailed consideration has not been given to the connection between these substrates.

[0005] The present invention aims to provide a suitable antenna device having multiple substrates. [Means for solving the problem]

[0006] To achieve the above-mentioned objectives, the antenna device according to the present invention is An antenna device, A first substrate comprising an antenna array having a plurality of active antennas, each including a semiconductor structure for generating or detecting electromagnetic waves and an antenna, and wiring electrically connected to the plurality of active antennas, A second substrate is laminated with the first substrate and includes a control circuit for the antenna array, Equipped with, The first substrate and the second substrate are joined by a bonding surface. The control circuit is electrically connected to the antenna array via the wiring, The control circuit of the second substrate controls the operation of the plurality of active antennas of the first substrate. It is characterized by the following: [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a suitable antenna device having multiple substrates. [Brief explanation of the drawing]

[0008] [Figure 1] (a) is a block diagram showing the antenna device 10, (b) is a schematic top view showing the first circuit board 151 of the antenna device 10, (c) is a schematic top view showing the second circuit board 152 of the antenna device 10, and (d) is a schematic top view showing the second circuit board 152 of the antenna device 10. [Figure 2A] This is a top view of the antenna device according to Embodiment 1. [Figure 2B] (1) is a cross-sectional view A-A' of the antenna device according to Embodiment 1, (2) is a cross-sectional view B-B' of the antenna device according to Embodiment 1, and (3) is a cross-sectional view C-C' of the antenna device according to Embodiment 1. [Figure 3A] This is a top view of the antenna device according to Embodiment 2. [Figure 3B] (1) is a cross-sectional view of the antenna device according to Embodiment 2, (2) is a cross-sectional view of the antenna device according to Embodiment 2, and (3) is a cross-sectional view of the antenna device according to Embodiment 2, taken along line C. [Figure 4A] This is a top view of the antenna device according to Embodiment 3. [Figure 4B] (1) is a cross-sectional view of the antenna device according to Embodiment 3 along line A-A', (2) is a cross-sectional view of the antenna device according to Embodiment 3 along line B-B', and (3) is a cross-sectional view of the antenna device according to Embodiment 3 along line C-C'. [Figure 5A] This is a top view of the antenna device according to Embodiment 4. [Figure 5B] (1) is a cross-sectional view of the antenna device according to Embodiment 4, (2) is a cross-sectional view of the antenna device according to Embodiment 4, and (3) is a cross-sectional view of the antenna device according to Embodiment 4, taken along line C. [Figure 6] (a) This figure shows an example configuration of a camera system using an antenna device, and (b) an example configuration of a communication system using an antenna device. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] The following explanation will focus on the use of the antenna device as a receiving device for detecting terahertz waves, but it is also possible to use the antenna device as a transmitting device for emitting terahertz waves. Here, terahertz waves refer to electromagnetic waves in the frequency range of 10 GHz to 100 THz, for example, 30 GHz to 30 THz.

[0011] [Embodiment 1] (Stacked block diagram) The configuration of the antenna device 10 according to this embodiment will be explained with reference to Figure 1. Figure 1(a) is a block diagram illustrating the chip configuration of the antenna device 10. Figure 1(b) is a schematic top view of the first substrate 151 constituting the device 10, viewed from above. Figures 1(c) and (d) are examples of schematic top views of the second substrate 152 constituting the antenna device 10, viewed from above.

[0012] In Figure 1(a), the antenna device 10 consists of n active antennas AA1 to AA arranged in an array. n The system comprises a first substrate 151 on which an active antenna array 11 is integrated, and a second substrate 152 equipped with a control circuit for individually controlling the active antennas.

[0013] Each active antenna AA of the active antenna array 11 on the first substrate 151 11 ~AA mnIt includes a semiconductor structure which is a semiconductor layer (compound semiconductor layer) 100 for transmitting and receiving terahertz waves, and a conductor layer 101 on which wiring is formed. The conductor layer 101 is also referred to as an antenna wiring layer. Therefore, as shown in Fig. 1(a), the active antenna array 11 is an antenna array in which antennas are arranged in a matrix of m rows and n columns (m≥2, n≥2).

[0014] The second substrate 152 includes a control unit (control circuit) 165 for individually controlling the active antennas AA 11 ~AA mn The control circuit 165 has a plurality of control elements AC 11 ~AC mn In this embodiment, the control units AC 11 ~AC mn are connected to the active antennas AA 11 ~AA mn in a one-to-one relationship, and are arranged in a matrix in the same manner as the active antennas AA 11 ~AA mn Here, the control units AC 11 ~AC mn of the second substrate 152 may be arranged in the region directly below the corresponding antennas AA 11 ~AA mn In this case, the wiring length between the corresponding antenna AN mn and the control unit AC mn is the shortest, and the wiring lengths for connecting each antenna and the control unit are substantially equal, so that the wiring inductance can be reduced. For example, as shown in Fig. 1(c), the second substrate 152 includes a bias control unit 12, a phase control unit 13, a baseband integrated circuit (IC) 17, and an analog-to-digital converter (ADC) / digital-to-analog converter (DAC) 16, and is connected to a control circuit 165 arranged in the center of the second substrate 152. The control circuit 165 includes an integrated circuit of electronic components such as an ON / OFF switch for each antenna, a transistor for controlling a bias signal to the semiconductor layer 100, and a transistor for controlling the phase and output of each antenna.

[0015] Furthermore, as shown in the line drive circuit in Figure 1(d), the second substrate 152 may be configured to include a bias control unit 12, a vertical shift register 14, a horizontal shift register 15, and an ADC / DAC 16, and be connected to a control circuit 165 located in the center of the second substrate 152. In this case, the control circuit 165 includes a semiconductor structure which is an electronic integrated circuit, such as a switch for switching the matrix controlled by the signals from the shift registers, a transistor for controlling the bias signal to the semiconductor layer 100, and transistors for controlling the phase and output of each antenna. Also, when an active antenna is used as a receiver, the control circuit 165 may be configured to include a preamplifier or a low-noise amplifier. The control circuit 165 is an electronic integrated circuit based on transistors, and any silicon (Si) device can optionally use CMOS (Complementary Metal Oxide Semiconductor) of 90 nm or later and FinFET (Fin Field-Effect Transistor) of 10 nm or later. Furthermore, electronic integrated circuits based on transistors of compound semiconductor devices operating in the terahertz band, such as silicon germanium (SiGe)-BiCMOS, SiGe-HBT (Heterojunction Bipolar Transistor), indium gallium arsenide (InGaAs) / indium phosphide (InP)-high electron mobility transistors (HEMTs), InGaAs / InP-HBTs, and gallium nitride (GaN)-HEMTs, can also be used. Here, BiCMOS is a semiconductor circuit that combines bipolar and CMOS circuits. The following embodiments will describe the case where Si-MOS-FETs are used as transistors, but the scope of the present invention is not limited to this.

[0016] (3x3 active antenna array) Figures 2A and 2B show the active antenna array 11 within the antenna device 10. As shown in Figure 2A, square patch antennas are used for the antenna, and nine patch antennas are arranged in a 3x3 matrix array. Each of the active antennas AA1 to AA9 integrates at least one antenna and a semiconductor layer 100 which is an oscillation source, and the oscillation frequency f THz The terahertz waves are radiated perpendicular to the surface of the substrate. Each active antenna's semiconductor layer 100 includes a semiconductor structure for generating or detecting terahertz waves, and in this embodiment, an example using a resonant tunneling diode (RTD) is described. Note that the semiconductor layer 100 can be any semiconductor having electromagnetic wave gain or carrier nonlinearity (nonlinearity of current due to voltage change in the current-voltage characteristic) for terahertz waves, and is not limited to RTDs. The bias control unit 12 shown in Figure 1 is a power supply for controlling the bias signal applied to the semiconductor layer 100 and is electrically connected to the semiconductor layer 100.

[0017] In the active antenna array 11 described in this embodiment, each active antenna is connected to the others by a coupling line CL, which is a transmission line, and is electrically connected. The coupling line CL, which is a transmission line, transmits the frequencies f between the antennas. THz Mutual injection synchronization is possible. For example, between active antennas AA1 and AA2, the coupling line CL 12 They are connected by the connecting line CL 12 In the middle, there is an impedance variable VZ1 for adjusting the impedance of the coupling line between active antennas AA1 and AA2. In the example of the 3x3 array shown in Figure 2A, two coupling lines CL, which are microstrip lines, are used to synchronize active antennas AA1 and AA4 horizontally. 14a and CL 14b The connection is made. (Connecting line CL) 14a and CL 14b These are the impedance variable VZ 14a and VZ 14bA coupling wire CL is connected between the active antennas AA1 and AA2 for vertical synchronization. 12 And the impedance variable VZ connected in between. 12a They are placed.

[0018] (Active antenna configuration) Figures 2B(1) to 2B(3) are cross-sectional views A-A', B-B', and C-C' of the active antenna array 11. Active antenna AA serves as both a resonator that resonates with terahertz waves and a radiator that transmits or receives terahertz waves. In the antenna array, each active antenna can be arranged at a pitch (spacing) that is less than or equal to the wavelength of the detected or generated terahertz wave, or an integer multiple of that wavelength. Active antenna AA has at least a conductor layer (antenna layer, upper conductor layer) 101 (AA1) which is the upper conductor of the patch antenna, a conductor layer 109 which is both a GND layer and a reflector layer, and a semiconductor layer 100 arranged between them. The semiconductor layer 100 uses a resonant tunneling diode (RTD) in the semiconductor structure 162. An RTD is a typical semiconductor structure that has electromagnetic wave gain in the terahertz wave frequency band and is also called an active layer. The active antenna AA further includes a via 103 for connecting the conductor layer 101 and the semiconductor layer 100, and a conductor layer 111 that serves as the upper conductor of the coupling line CL. A conductor layer 102 is also placed between the conductor layer 101 and the conductor layer 109 to form a bias wiring, and the conductor layer 102 is located between the dielectric layer 104 and the dielectric layer 105. The bias wiring layer 102 is connected to the conductor layer 101 via wiring 108 and via 107. The conductor layer 109, which is the GND layer, is grounded.

[0019] As shown in (1) of Figure 2B, the semiconductor layer 100 is stacked in the order of lower electrode layer 164, semiconductor structure 162, and upper electrode layer 163 from the conductor layer 109 side, and these are electrically connected. The semiconductor structure 162 is a semiconductor structure that has electromagnetic wave gain or nonlinearity for terahertz waves, and in this embodiment, an RTD is used. The upper electrode layer 163 and lower electrode layer 164 are structures that also serve as electrode layers for connecting the upper and lower contact electrodes (ohmic or Schottky) of the semiconductor structure 162 and the upper and lower wiring layers in order to apply a potential difference or current to the semiconductor structure 162. The upper electrode layer 163 and lower electrode layer 164 can be composed of metallic materials (Ti, Pd, Au, Cr, Pt, AuGe, Ni, TiW, Mo, ErAs, etc.) known as ohmic electrodes or Schottky electrodes, or semiconductors doped with impurities.

[0020] The active antenna AA1 includes a conductor layer 101, a semiconductor layer 100, a conductor layer 109 (reflector), dielectric layers 104 and 105, and vias 103 connecting the conductor layer 101 and the semiconductor layer 100. In addition, a conductor layer 102 and vias 107, which form bias wiring individually provided for each antenna, a Metal Insulator Metal (MIM) capacitor 126, and a resistive layer 127 are connected to the active antenna AA1 to apply a control signal to the semiconductor layer 100. The MIM capacitor 126 is a capacitive element in which metal and metal are sandwiched between insulating layers, and is arranged to suppress low-frequency parasitic oscillations caused by the bias circuit. In this embodiment, the MIM capacitor 126 uses a structure in which a part of the dielectric layer 106 is sandwiched between a conductor layer 113 and a conductor layer 109 which is GND.

[0021] (Antenna array) To increase the gain of the active antenna array 11, it is conceivable to arrange multiple active antennas AA1 to AA9 in an array. Each active antenna has a semiconductor layer 100 including an RTD as described above, and the gain of the array antenna is increased by mutual injection synchronization between the active antennas. In order to synchronize the multiple active antennas AA1 to AA9, a coupling line CL is required to connect adjacent antennas. Each active antenna and each coupling line are connected by capacitive coupling. The length of the coupling line CL is designed so that when adjacent antennas are connected by the coupling line, the phase matching condition is satisfied in either the lateral direction (magnetic field direction, H direction) or the vertical direction (electric field direction, E direction), or both. It should be noted that the present invention is applicable not only to antennas that radiate horizontal and vertical polarization as described above, but also to antennas that radiate circular polarization. For example, circular polarization can be radiated by making the conductor layer 101 of a patch antenna a rectangle instead of a square and forming a notch. Alternatively, an antenna that radiates circular polarization different from that of a patch antenna may be applied.

[0022] In one example, the coupling line is designed to be such that the electrical distance between adjacent antenna RTDs is an integer multiple of 2π. For example, a coupling line CL extending horizontally. 14 This is the length at which the electrical length between the semiconductor layers 100 of active antennas AA1 and AA4 is 4π. Also, the coupling line CL extends in the vertical direction. 12 This is the length at which the electrical length between the semiconductor layers 100 of active antennas AA1 and AA2 is 2π. Here, the electrical length is the wiring length considering the propagation speed of high-frequency waves propagating within the coupling line. With this design, the semiconductor layers 100 of each active antenna AA1 to AA9 are mutually injected and synchronized in positive phase. The error in the length range is ±1 / 4π.

[0023] In the middle of the coupling wire CL1 connecting adjacent active antennas AA1 and AA2, there is an impedance variable VZ for adjusting the impedance of coupling wire CL1. 12The device is equipped with the following features. In this embodiment, a MOS-FET, which is advantageous in terms of circuit integration and cost reduction, is used as the impedance variable VZ. The configuration consists of a first substrate 151 integrating an antenna array for transmitting and receiving terahertz waves and a semiconductor layer 100 made of a compound semiconductor (semiconductor structure), and a second substrate 152 including a CMOS integrated circuit for controlling the antenna array, which are joined at a junction surface BS. This configuration is realized by stacking the compound semiconductor antenna substrate including the antenna array and the Si integrated circuit substrate using semiconductor stacking technology.

[0024] (Explanation of layered structure) As shown in (1) of Figure 2B, the semiconductor layer 100 is stacked in the order of lower electrode layer 164, semiconductor structure 162, and upper electrode layer 163 from the conductor layer 109 side, and these are electrically connected. The semiconductor structure 162 is a semiconductor structure that has electromagnetic wave gain or nonlinearity for terahertz waves, and in this embodiment, an RTD is used. The upper electrode layer 163 and lower electrode layer 164 are structures that also serve as electrode layers for connecting the upper and lower contact electrodes (ohmic or Schottky) of the semiconductor structure 162 and the upper and lower wiring layers in order to apply a potential difference or current to the semiconductor structure 162. The upper electrode layer 163 and lower electrode layer 164 can be composed of metallic materials (Ti, Pd, Au, Cr, Pt, AuGe, Ni, TiW, Mo, ErAs, etc.) known as ohmic electrodes or Schottky electrodes, or semiconductors doped with impurities.

[0025] Each active antenna AA consists of a conductor layer 101, a semiconductor layer 100, a conductor layer 109 (reflector), dielectric layers 104 and 105, and vias 103 connecting the conductor layer 101 and the semiconductor layer 100. In addition, to apply a control signal to the semiconductor layer 100, as shown in (2) and (3) of Figure 2B, a conductor layer 102 and vias 107, a MIM capacitor 126, and a resistive layer 127, which form bias wiring individually provided for each active antenna, are connected to the active antenna AA. The MIM capacitor 126 is a capacitive element consisting of metal sandwiched between insulating layers, and is placed to suppress low-frequency parasitic oscillations caused by the bias circuit. Active antennas AA1 to AA9 are connected by a transmission line CL for synchronizing each antenna at a terahertz frequency.

[0026] A bonding surface BS is provided on the lower surface of the first substrate 151, which integrates an antenna array and a compound semiconductor. The first substrate 151 is bonded to a second substrate 152, which includes an integrated circuit, via this bonding surface BS. Here, "bonding" is defined as the first substrate 151 and the second substrate 152 sharing the same bonding surface BS. The second substrate 152 to be bonded is composed of a semiconductor substrate, which is the base material, and an integrated circuit region in which the drive circuit is formed. The two different types of substrates 151 and 152 are bonded using metal bonding such as CuCu bonding, SiO2 bonding, etc. X / SiO X Bonding is performed by insulating bonding, adhesive bonding using adhesives such as BCB, and hybrid bonding which is a combination of these. The bonding process includes low-temperature bonding using plasma activation and conventional thermocompression bonding. Furthermore, methods such as bonding semiconductor wafers of the same size, bonding semiconductor wafers of different sizes, and bonding multiple semiconductor chips to a wafer at intervals (tiling) are used.

[0027] In the active antenna array 11, the mesa structure of the semiconductor layer 100 is embedded by a dielectric layer 105 that surrounds it. The surface of the dielectric layer 105 on the junction surface BS side is planarized, and a conductor layer 109 that acts as a reflector is provided on this planarized surface. The dielectric layer 105 plays a role as a dielectric material that constitutes the antenna, and at the same time, it also plays a role as a planarization film in the manufacturing process that transfers the mesa structure of the semiconductor layer 100 to a different substrate. For example, silicon oxide (SiO₂) can be used as the dielectric layer 105. X ), silicon nitride (SiN X Inorganic insulating materials such as silicon oxynitride (SiON), silicon dioxide (SiOC), and silicon carbide (SiC) are used. The active antenna array 11 consists of an antenna region 52 (within the conductor layer 101, which is the upper conductor of the patch antenna) on which the antenna is provided, and a peripheral region 51 outside the antenna region on which bias wiring and transmission lines CL are provided. The antenna region 52 refers to the region that overlaps with the conductor layer 101, which is the upper conductor of the patch antenna, in the stacking direction of the substrate, and the peripheral region 51 refers to the region that does not overlap with the conductor layer 101, which is the upper conductor of the patch antenna. In one example, the peripheral region 51 refers to a region that does not overlap with the conductor layer 101, which is the upper conductor of the patch antenna, and is at least 1 / 10 of the wavelength of a terahertz wave away from the conductor layer 101. That is, the antenna region 52 is a region that includes the near-boundary of the terahertz wave, and the peripheral region 51 is a region that does not include the near-boundary of the terahertz wave.

[0028] On the side of the first substrate 151 opposite the second substrate 152, the layers are stacked in the order of conductor layer 109, dielectric layer 105, dielectric layer 104, and dielectric layer 112. Vias 103, via 107, and via 124, and conductor layers 101, 102, and 111 connected to them are formed on dielectric layers 105 and 104, respectively. The junction surface BS side of the first substrate 151 with the second substrate 152 is positioned opposite the semiconductor layer 100, with the reflector conductor layer 109 in between. The wiring layer conductor layer 102 is provided between the antenna layer conductor layer 101 and the reflector layer conductor layer 109. On the first substrate 151, the dielectric layer 105 on the second substrate 152 side is stacked in the order of a conductor layer 109 and an insulator layer 131, with through vias 137 and a bonding electrode layer 138 formed within the insulator layer 131. The insulator layer 131 and the electrode layer 138 are flattened at the bonding surface BS, and the bonding process is carried out with the flat bonding surface BS exposed. The second substrate 152 is stacked in the order of a semiconductor substrate 134, an insulator layer 133, a conductor layer 140, and an insulator layer 132, with vias 141 and a bonding electrode layer 139 formed within the insulator layer 132. The insulator layer 132 and the electrode layer 139 are flattened at the bonding surface BS, and the bonding process is carried out with the flat bonding surface BS exposed. Therefore, the bonding surface BS is provided between the conductor layer 109, which is a reflector, and the second substrate 152, which is a control circuit board. This configuration separates the antenna and control circuit, thus reducing noise caused by radio interference between the active antenna array operating at terahertz frequencies and the control circuit operating at RF frequencies. Insulator layers 131 to 134 are made of silicon oxide (SiO₂). X ), silicon nitride (SiN X The insulating layer can be formed using inorganic insulating materials such as silicon oxynitride (SiON), silicon dioxide (SiOC), and silicon carbide (SiC). Alternatively, the insulating layer 131 may be made from a compound semiconductor substrate.

[0029] Figure 2B(1) is a cross-sectional view of the antenna array 41 along line A-A'. The transmission line CL and the conductor layer 109, which acts as a reflector, of the first substrate 151, which integrates compound semiconductors, are electrically connected to the phase control transistor TRa (MOS-FET) and the conductor layer 140, respectively, which are located in the integrated circuit region of the second substrate 152. The conductor layer 111, which is the upper conductor of the transmission line CL of the first substrate 151, is connected to vias 124 formed in the dielectric layers 104 and 105, and to a wiring layer 135c provided in the opening 136c of the dielectric layer 104. Furthermore, the wiring layer 135c is electrically connected in the order of through via 137c provided in the insulator layer 131 and the bonding electrode layer 138c. With this configuration, the conductor layer 111 reaches the bonding surface BS. In addition, the transistor TR formed in the integrated circuit region of the second substrate 152 is connected in the order of via 141c formed in the integrated circuit region and the bonding electrode layer 139c, and reaches the bonding surface BS. The electrode layer 138c of the first substrate 151 and the electrode layer 139c of the second substrate 152 are electrically connected at the junction surface BS, thereby enabling conduction between the transmission line CL of the antenna array and the transistor TRa of the integrated circuit region 154, making it possible to apply a control signal. The transistors TRa and TRb are formed near the surface of the second semiconductor substrate 134, which is the base material of the second substrate 152.

[0030] Figure 2B(1) shows a cross-section of the active antenna array 11 along the line A-A'. The transmission line CL and the conductor layer 109, which acts as a reflector, of the first substrate 151, which integrates compound semiconductors, are electrically connected to the phase control transistor TRa (MOS-FET) and the conductor layer 140, which corresponds to the second GND, located in the integrated circuit region 154 of the second substrate 152. The conductor layer 111 is the upper conductor of the transmission line CL of the first substrate 151. The conductor layer 111 is electrically connected to the junction surface BS in the following order: vias 124 formed in the dielectric layers 104 and 105, wiring layer 135c provided in the opening 136c of the dielectric layer 104, through via 137c provided in the insulator layer 131, and bonding electrode layer 138c. In addition, the transistor TR formed in the integrated circuit region 154 of the second substrate 152 reaches the junction surface BS by being connected in the following order: via 141c formed in the integrated circuit region 154 and bonding electrode layer 139c. The electrode layer 138c of the first substrate 151 and the electrode layer 139c of the second substrate 152 are electrically connected at the junction surface BS, thereby enabling conduction between the transmission line CL of the antenna array and the transistor TRa of the integrated circuit region 154, making it possible to apply a control signal. Transistors TRa and TRb are formed near the surface of the second semiconductor substrate 134, which is the base material of the second substrate 152.

[0031] Similarly, the conductor layer 109, which is the reflector in the antenna of the first substrate 151, is electrically connected to the bonding surface BS in the order of through via 137g provided in the insulating layer 131 and bonding electrode layer 138g. Also, the conductor layer 140, which is the GND of the second substrate 152, is connected to the bonding surface BS in the order of via 141g formed in the insulating layer 132 and bonding electrode layer 139g. The GND potential of both substrates is shared by the electrical connection of the electrode layer 138g of the first substrate 151 and the electrode layer 139g of the second substrate 152 at the bonding surface BS. As an example of increasing the bonding strength, dummy electrode layers 138d and 139d that are not connected to signal lines may be provided at the bonding surface BS. By widely distributing the dummy electrode layers 138d and 139d in areas where wiring electrodes are not required, the bonding strength can be increased, and yield and reliability can be improved. Furthermore, by widely distributing the GND electrode layers 138g and 139g and the dummy electrode layers 138d and 139d across the entire junction surface BS, the influence of electromagnetic noise originating from the integrated circuit of the second substrate 152 on the terahertz antenna of the first substrate 151 can be reduced.

[0032] Similarly, the conductor layer 109, which acts as a reflector in the antenna of the first substrate 151, is electrically connected to the junction surface BS via a through via 137g provided in the insulator layer 131 and a bonding electrode layer 138g in that order. The conductor layer 101, which is the upper conductor, and the conductor layer 109, which has a larger area than the upper conductor formed on the conductor layer 101 and acts as GND, function as a patch antenna that resonates with terahertz waves. In addition, the conductor layer 140, which is the GND of the second substrate 152, is connected to the junction surface BS via a via 141g formed in the integrated circuit region 154 and a bonding electrode layer 139g in that order. The electrode layer 138g of the first substrate 151 and the electrode layer 139g of the second substrate 152 are electrically connected at the junction surface BS, so that the GND potential of both substrates is shared. By arranging a conductor layer 140 as a second GND in addition to the conductor layer 109, which is a reflector and the first GND, it becomes possible to reduce noise caused by radio wave interference between the active antenna array operating at terahertz frequencies and the control circuit operating at RF frequencies. To enhance the noise reduction effect, it is preferable that the conductor layers 109 and 140, which are GNDs, be solid planes. As an example of increasing the bonding strength, dummy electrode layers 138b and 139b that are not connected to signal lines may be provided on the bonding surface BS. By widely distributing the dummy electrode layers 138b and 139b in areas where wiring electrodes are not required, the bonding strength can be increased, contributing to improved yield and reliability. Furthermore, by widely distributing the GND electrode layers 138g, 139g and dummy electrode layers 138b and 139b on the bonding surface BS, the influence of electromagnetic wave noise originating from the integrated circuit of the second substrate on the antenna of the first substrate 151 can be reduced.

[0033] Figure 2B(2) is a cross-sectional view of the antenna array 41 along the line B-B'. A conductor layer 102, which forms a bias wiring connected to the compound semiconductor layer of the first substrate 151, is electrically connected to a transistor TRb (MOS-FET), which is a bias control circuit, provided in the integrated circuit region of the second substrate 152. The conductor layer 102 is electrically connected in the following order: via 107 formed in the dielectric layer 105, wiring layer 135b provided in the opening 136b of the conductor layer 109 which is a reflector, through via 137b provided in the insulator layer 131, and bonding electrode layer 138b. This allows the wiring layer 102 to reach the bonding surface BS. Similarly, the transistor TRb formed in the integrated circuit region of the second substrate 152 is connected in the following order: via 141b formed in the integrated circuit region and bonding electrode layer 139b, reaching the bonding surface BS. Then, the electrode layer 138b of the first substrate 151 and the electrode layer 139b of the second substrate 152 are electrically connected at the bonding surface BS. This creates conductivity between the wiring layer 102 for biasing the antenna array and the transistor TRa in the integrated circuit region, making it possible to apply individual control signals to each antenna.

[0034] Figure 2B(2) shows a B-B' cross-section of the active antenna array 11. A bias wiring layer 102 connected to the compound semiconductor layer of the first substrate 151 is electrically connected to a transistor TRb (MOS-FET), which is a bias control circuit, provided in the integrated circuit region 154 of the second substrate 152. The bias wiring layer 102 of the first substrate 151 is electrically connected to the junction surface BS in the following order: via 117, wiring layer 135b provided in the opening 136b of the conductor layer 109 which is a reflector, through via 137b provided in the insulator layer 131, and bonding electrode layer 138b. Here, the opening 136 and each electrode (wiring layer 135, through via 137, and conductor layer 138) that electrically connect the first substrate 151 and the second substrate 152 are provided in the peripheral region 51. By arranging the reflector opening 136 and bonding members in positions that do not overlap with the antenna region, improved radiation efficiency and noise reduction effects can be expected. However, it is not always necessary to place them in the peripheral region 51. For example, if the influence on the antenna is negligible, it can be ignored if it is sufficiently small compared to the electrical length of the electromagnetic waves expected to propagate through the aperture 136, wiring layer 135, and through via 137 (typically less than 1 / 10 of the electrical length λ). In this case, the aperture 136, wiring layer 135, and through via 137 may be placed within the antenna region.

[0035] Similarly, the transistor TRb formed in the integrated circuit region 154 of the second substrate 152 is electrically connected to the junction surface BS via 141b formed in the integrated circuit region 154 and then to the junction electrode layer 139b. The electrode layer 138b of the first substrate 151 and the electrode layer 139b of the second substrate 152 are electrically connected at the junction surface BS, causing the transistor TRa between the wiring layer 102 for biasing the antenna array and the integrated circuit region 154 to conduct. This makes it possible to apply control signals to each antenna individually.

[0036] The transistor TRa, which is a phase control circuit, adjusts the impedance of the transmission line CL by connecting the source and drain of a MOS-FET in the middle of the transmission line CL, thereby using a variable resistor or switching operation. Furthermore, the transistor TRa for phase control can also be used as a variable capacitor by connecting its gate and source. The MOS-FET of the transistor TRa, which is a bias control circuit, also functions as a bias control unit, supplying a bias signal to the semiconductor layer 100 by operating as a switching regulator. Alternatively, a configuration may be adopted in which a terminal for applying the bias signal is provided separately on the second substrate 152, causing the transistor TRa to operate as an analog switch and supplying voltage from outside the second substrate 152.

[0037] (Device operation) The active antenna array 11 shown in Figures 2A and 2B uses a hybrid coupler as an impedance variable. The active antenna array 11 has four hybrid couplers VZ 1245 VZ 2356 VZ 4578 , and VZ 5689 It has two coupling wires CL that connect adjacent 2x2 array active antennas. For example, active antennas AA1, AA2, AA4, and AA5 are connected by two coupling wires CL. 14b and CL 25a Hybrid coupler VZ placed in the middle 1245 It connects to the Hybrid Coupler VZ. 1245 It has four impedance variables VZ 12b VZ 45a VZ 14b , and VZ 25a It consists of, of which, the impedance variable VZ 12b and VZ 45a The two connecting lines CL 14b and CL 25a They are connected so as to connect them vertically, and the ON / OFF switch controls the coupling line CL 14b and CL 25a Switches the coupling. Also, the impedance variable VZ 14b The connecting line CL14b The impedance variable VZ 25a The connecting line CL 25a It is located in the middle and is a switch that switches the coupling between adjacent antennas. Hybrid Coupler VZ 1245 It is possible to control the intermodulation within the antenna to create a phase difference between ports. Alternatively, the electrical length of the coupling line CL can be changed simply by changing the impedance of the impedance variable VZ from capacitive to inductive. In this case, the phase difference between adjacent active antennas can be adjusted to a certain value, and the phase of the coupling line CL between active antennas AA1 to AA9 can be adjusted. This allows beamforming to be performed by creating an arbitrary phase difference between each active antenna AA1 to AA9.

[0038] In a terahertz wave active array antenna, multiple wires are required to individually control each antenna, including bias lines that energize the compound semiconductor, synchronization lines that control the synchronization between antennas, and control lines that inject baseband signals into the antennas. On the other hand, increasing the number of antennas is necessary to improve antenna gain, but as the number of antennas increases, the wiring inductance due to the layout increases, which can hinder higher frequencies. In contrast, in this embodiment, a compound semiconductor antenna substrate (first substrate 151) containing the antenna array and a Si integrated circuit substrate (second substrate) 152 are stacked using semiconductor bonding technology. This eliminates the need to integrate the peripheral circuits necessary for controlling the active antenna array on the compound semiconductor substrate or to use an external connection method. As a result, the increase in inductance due to wiring is suppressed, and can typically be suppressed to 1 nH or less, thereby suppressing signal loss and signal delay of baseband signals modulated and controlled at high frequencies of 1 GHz or higher.

[0039] Furthermore, since there are no circuits unrelated to the transmission and reception of terahertz waves around the antenna, or the number of such circuits can be significantly reduced, noise due to unwanted reflections is reduced, and the antenna's characteristics can be maximized. When controlling the bias signal of a compound semiconductor for each antenna, it is necessary to arrange each bias wiring individually. In contrast, in this embodiment, the first substrate 151, which includes the antenna array, can be directly connected to the integrated circuit of the second substrate 152 via through vias 137b, 137c, 137d, and 137g. When using an active antenna array, wiring can be arranged on the back side of the compound semiconductor antenna substrate (first substrate 151) including the antenna array (i.e., the back side of the conductor layer 109 that acts as a reflector). Therefore, the number of active antennas included in the antenna array can be increased without being affected by the layout. In addition, the second substrate 152, which includes the integrated circuit, can be configured with complex circuits such as detection circuits and signal processing circuits using conventional CMOS integrated circuit technology. Therefore, by using a configuration like that of this embodiment, it is possible to improve the sophistication and cost reduction of the antenna device, and to easily utilize terahertz electromagnetic waves.

[0040] [Embodiment 2] Figure 3A shows a plan view of the antenna array 21, which is the second embodiment, and Figures 3B(1), 3B(2), and 3B(3) show the A-A', B-B', and C-C' cross-sections of the antenna array 21, respectively. In the antenna array 21, a semi-insulating InP substrate (4 inches), which is a compound semiconductor substrate obtained by crystal growth of a compound semiconductor, was used as the insulating layer 131 of the first substrate 151 on which the compound semiconductor is integrated. Hereinafter, in this embodiment, the insulating layer 131 will be described as a semiconductor layer. Here, from the viewpoint of reducing wiring inductance, it is preferable to thin the thickness of the semiconductor substrate 10 to 100 μm or less, preferably to 10 μm or less. The plate thickness is designed to be within the range of 1 / 10 or less of the wavelength of the terahertz wave to be operated. In one example, the plate thickness is 1 / 20 or less of the wavelength of the terahertz wave to be operated.

[0041] A bonding surface BS is provided on the lower surface of the semiconductor substrate 131, which is the base material of the first substrate 151, and the second substrate 152, which includes an integrated circuit, is bonded to it. In this embodiment, Cu-Cu bonding and SiO X / SiO X Using a hybrid bonding method, tiling is performed by bonding the cut-out first substrate 151 to a 12-inch Si integrated circuit substrate.

[0042] The first substrate 151 is laminated in the following order from the junction surface BS with the second substrate 152: insulating layer 148, semiconductor substrate 131, conductor layer 109, insulating layers 105, 104, and 112. Vias 103, 107, and 117 and conductor layers 101, 102, and 111 are formed on insulating layers 105 and 104, respectively. The junction surface BS side of the first substrate 151 with the second substrate 152 is positioned opposite the semiconductor layer 100, with the conductor layer 109 acting as a reflector in between. Through-vias 137 are formed within the semiconductor substrate 131, penetrating through the substrate. Copper (Cu) or gold (Au) are preferably used as the material for the through-vias 137. The insulating layer 148 and electrode layer 138 for bonding are planarized at the junction surface BS, and the bonding process is carried out with the flat junction surface BS exposed. On the second substrate 152 side, the semiconductor substrate 134, which is the base material, and the insulating layer 132 are stacked in that order. Conductor layers 140, vias 141, and electrode layers 139 for bonding are formed within the insulating layer 132 to constitute the multilayer wiring. The insulating layer 132 and the electrode layer 139 are planarized at the bonding surface BS, and the bonding process is carried out with the flat bonding surface BS exposed. The insulating layers 132 and 148 are made of silicon oxide (SiO₂). X ), silicon nitride (SiN XInorganic insulating materials such as silicon oxynitride (SiON), silicon oxide (SiOC), and silicon carbide (SiC) are used. As described above, the plate thickness is designed to be less than or equal to 1 / 10 of the wavelength of the terahertz wave being operated. Therefore, the distance between the conductor layer 111 and the semiconductor substrate 134 can also be less than or equal to 1 / 10 of the wavelength of the terahertz wave, and the impedance of the through via 137, the bonding electrode layers 138 and 139, and the via 141 can be reduced.

[0043] Figure 3B(1) shows a cross-section of the antenna array 21 along the line A-A'. Active antennas AA1~AA on the first substrate 151 n The conductor layer 109, which acts as a reflector, is electrically connected to the junction surface BS in the order of through via 137g provided in the semiconductor substrate 131 and bonding electrode layer 138g formed in the insulating layer 148. In addition, the conductor layer 140, which is the GND of the second substrate 152, reaches the junction surface BS by being connected in the order of via 141g formed in the integrated circuit region 154 and bonding electrode layer 139g. The electrode layer 138g of the first substrate 151 and the electrode layer 139g of the second substrate 152 are electrically connected at the junction surface BS, thereby sharing the GND potential of both substrates.

[0044] Figure 3B(2) shows a B-B' cross-section of the antenna array 21. A bias wiring layer 102 connected to the semiconductor layer 100 of the first substrate 151 is electrically connected to a bias control transistor TRb (MOS-FET) provided in the integrated circuit region 154 of the second substrate 152. The bias wiring layer 102 is electrically connected to the junction surface BS by being connected in the following order: via 117 formed in the dielectric layer 105, wiring layer 135b provided in the opening 136b, through via 137b provided in the semiconductor substrate 131, and electrode layer 138b provided in the insulator layer 148. Similarly, the transistor TRb formed in the integrated circuit region 154 of the second substrate 152 reaches the junction surface BS by being connected in the following order: via 141b formed in the integrated circuit region 154 and junction electrode layer 139b.

[0045] At the junction surface BS between the electrode layer 138b of the first substrate 151 and the electrode layer 139b of the second substrate 152, each antenna is electrically connected individually. This allows the wiring layer 102 for biasing the antenna array and the transistor TRa in the integrated circuit region 154 to conduct, enabling the application of individual control signals to each antenna. The MOS-FET of transistor TRb in the bias control wiring layer 102 also functions as a bias control unit, operating as a switching regulator to individually control the bias signal to the semiconductor layer 100. Alternatively, a terminal for applying the bias signal may be provided separately on the second substrate 152, and the transistor TRa may be operated as an analog switch to individually turn the antennas on and off, with voltage supplied from outside the second substrate 152. With such a configuration, by individually changing the bias of each active antenna, a phase difference can be created between adjacent antennas, thereby achieving beamforming.

[0046] [Embodiment 3] Figure 4A is a plan view of the antenna array 31, which is the third embodiment, and Figures 4B(1) to (3) show the A-A', B-B', and C-C' cross-sections of the antenna array 31, respectively. The antenna array 31 is an example in which wiring from the second substrate 152, which includes an integrated circuit, is electrically connected individually to the active antennas AA1 to AA9. The active antenna AA1 consists of an antenna conductor layer 101, two semiconductor layers 100a and 100b, a conductor layer 109 (reflector), dielectric layers 104 and 105, and vias 103a and 103b connecting the conductor layer 101 and the semiconductor layer 100. RTDs are used in the semiconductor layers 100a and 100b, and the two RTDs are positioned opposite each other with respect to a node of the resonant electric field in antenna AA (i.e., the position where the electric field of the standing wave of the terahertz wave is zero). In this configuration, the two RTDs oscillate in a push-pull mode, mutually injecting and synchronously synchronized with each other in a phase-inverted state (out of phase). As shown in Figure 4A, the configuration in which the RTDs are arranged symmetrically within the antenna, both horizontally and vertically, is a configuration that more easily yields the effect of improving directivity as the number of arrays increases.

[0047] To generate terahertz waves, the semiconductor layer 100 is stacked in the order of upper electrode layer 163, semiconductor structure 162, and lower electrode layer 164. The semiconductor structure 162 is an RTD formed on a semiconductor layer that has electromagnetic wave gain or nonlinearity for terahertz waves. The upper electrode layer 163 and lower electrode layer 164 are structures that have electrode layers for connecting to the upper and lower contact electrodes and upper and lower wiring layers of the semiconductor structure 162 in order to apply a potential difference or current to the RTD which is the semiconductor structure 162. The upper electrode layer 163 is connected to via 103, and the lower electrode layer 164 is connected to conductor layer 109, thereby providing a potential difference or current to the semiconductor structure 162. Therefore, it can be said that the upper electrode layer 163 and via 103, and the lower electrode layer 164 and conductor layer 109 are connected to two power lines, respectively.

[0048] A common bias wiring layer 102 is provided for all active antennas AA1 to AA9 in order to apply a bias control signal to the semiconductor layer 100. The wiring layer 102 transmits frequency f via vias 107a and 107b, which are arranged for each antenna. THz In this configuration, the position is set so that it is connected to the active antennas AA1 to AA9 at the node position of the resonant electric field formed on the active antennas AA1 to AA9. The wiring layer 102 is connected to the MIM capacitor 126 and the resistance layer 127, which are arranged for each antenna, and the frequency f THz By AC shorting out other high frequencies, the impedance at high frequencies is reduced. This suppresses multimode oscillation in the array antenna.

[0049] Figure 3B(3) shows a C-C' cross-section of the antenna array 31. A bias wiring layer 102 connected to the semiconductor layer 100 of the first substrate 151 is electrically connected to a bias control wiring layer 143 provided in the integrated circuit region 154 of the second substrate 152. The wiring layer 102 is electrically connected to the junction surface BS in the following order: via 117 formed in the dielectric layer 105, wiring layer 135b provided in the opening 136b of the conductor layer 109, through via 137b provided in the semiconductor substrate 131, and bonding electrode layer 138b provided in the insulator layer 148. Similarly, a transistor TRb formed in the integrated circuit region 154 of the second substrate 152 reaches the junction surface BS by being connected in the following order: via 141b formed in the integrated circuit region 154 and bonding electrode layer 139b. At the junction surface BS between the electrode layer 138b of the first substrate 151 and the electrode layer 139b of the second substrate 152, the wiring layer 102 for biasing the antenna array and the wiring layer 143 of the integrated circuit region 154 are conductive, allowing bias control signals to be applied to all antennas. The bias signal, which is separately provided on the second substrate 152, is supplied to the bias control wiring layer 143 from an external voltage via an application terminal.

[0050] Active antennas AA1 to AA9 are provided with vias 130 for coupling the injection synchronization signal from the master oscillator 60. Via 130 is capacitively coupled to the conductor layer 101 of the active antenna via capacitance C, and the master oscillator 60 and active antennas AA are electrically connected such that they are short in the terahertz band and open in the RF band. Via 130 also provides frequency f within the active antennas AA1 to AA9. THz The connection point is set so that it is connected at the node position of the resonant electric field. As a result, via 130 has a frequency f within the antenna. THz This results in high impedance and low impedance at subharmonic frequencies, achieving both terahertz radiation efficiency and master signal injection efficiency.

[0051] The master oscillator 60 emits terahertz waves at subharmonic frequencies (f THzThe master oscillator 60 is an oscillator source that oscillates at 2 / 2 and controls the phase of each active antenna. The master oscillator 60 outputs a signal larger than the output of the slave active antenna alone. Active antenna AA is electrically connected to the gate of the transistor TRa (MOS-FET) of the master oscillator 60, which is provided in the integrated circuit region 154 of the second substrate 152, via 130 for master oscillation. The master synchronization via 130 formed in the dielectric layers 104 and 105 of the first substrate 151 is electrically connected to the junction surface BS in the order of wiring layer 135a provided in the opening 136a of the conductor layer 109, through via 137a provided in the insulator layer 131, and bonding electrode layer 138a. Similarly, the transistor TRa formed in the integrated circuit region 154 of the second substrate 152 is electrically connected to the junction surface BS in the order of via 141a formed in the integrated circuit region 154 and bonding electrode layer 139b.

[0052] The electrode layer 138a of the first substrate 151 and the electrode layer 139a of the second substrate 152 are electrically connected at the junction surface BS. As a result, the transistor TRa, which is arranged in the active antenna array AA1 to AA9 and the integrated circuit region 154 for individually controlling each antenna, conducts in the terahertz band and becomes capable of receiving control signals. Each active antenna forms a bias structure that applies a potential difference from above and below the semiconductor structure 162 using the upper electrode layer 163 and via 103 and the lower electrode layer 164 and conductor layer 109. The subharmonic signal from the master oscillator 60 is injected into the semiconductor layers 100a and 100b via this bias structure. Therefore, the subharmonic frequency (f) from the master oscillator 60 is injected into the semiconductor layers 100a and 100b, which consist of RTDs that act as oscillation sources within the antennas. THz The phase of each active antenna can be controlled by injecting a power signal of ( / 2). A device with such a configuration uses harmonics (f) of an integer fraction of the terahertz band. THz As a master oscillator, which is a harmonic oscillator circuit that outputs f / n (where n is a natural number), the frequency f THz The active antenna array operating at frequency f is injected and synchronized. This synchronizes the frequency f of the active antenna array. THzThis allows for control of the timing in the process, enabling a reduction in phase noise.

[0053] [Embodiment 4] As a fourth embodiment, an example of using the present invention in a receiving device will be described. Figure 5A is a schematic top view of the antenna array 41 according to this embodiment, and Figures 5B(1) to 5B(3) are schematic cross-sectional views of the antenna array 41 in the A-A', B-B', and C-C' planes. The antenna array 41 has one central element which is a transmitting antenna 504 for transmission, and the eight elements surrounding it are receiving antennas 503 for reception.

[0054] The receiving antenna 503 is a patch antenna with a structure in which a negative resistance element 300 and a dielectric 312 are sandwiched between a conductor layer 507, which is the upper conductor for the receiving antenna, and a conductor layer 309, which is the reflector. The upper terminal of the negative resistance element 300 is electrically connected to via 301, and via 301 is electrically connected to conductor layer 507. The lower terminal of the negative resistance element 300 is electrically connected to conductor layer 309, which is also GND. Conductor layer 507 is f THz The individual bias conductor layer 303 is connected via a feed via 307, which supplies bias power at the node position of the resonant electric field. This structure allows bias to be applied above and below the negative resistance element 300. The conductor layer 303 is connected to the MIM capacitor 320 via the MIM capacitor connection section 321. The MIM capacitor connection section 321 has a resistive layer made of TiW and acts as an AC short connected in series with the MIM capacitor structure. When a signal of a predetermined bias voltage that generates negative resistance is applied to the negative resistance element, self-oscillation occurs, and the connection section plays a role in preventing output degradation and oscillation instability due to parasitic oscillation. The transmitting antenna 504 has almost the same configuration as the receiving antenna except that it has a conductor layer 1001 which is the upper conductor for the transmitting antenna. These antennas are connected and synchronized by multiple transmission lines 1808a to 1808r.

[0055] Figure 5A shows the cross-sectional structure of each active antenna 503 and 504. The back surface of the first substrate 151 has a bonding surface BS, which bonds the outermost surface on the bonding surface BS side of the semiconductor substrate 302, which is the base material of the first substrate 151, to the outermost surface on the bonding surface BS side of the second substrate 152, on which the integrated circuit is formed. The second substrate 152 has an integrated circuit region 154 formed thereon, which includes a semiconductor substrate 1901, which is the base material, and a control circuit 165 formed on the insulating layer 1902 of the integrated circuit. The bonding surface BS is a bonding interface in which the conductor layer 1910 formed on the back surface of the first substrate, the semiconductor substrate 302, and the conductor layer 1911 exposed on the outermost surface of the second substrate 152 are directly bonded. Here, the bonding form is a metal bonding such as Cu-Cu bonding, SiO X / SiO X Insulator bonding such as jointing, adhesive bonding using adhesives such as BCB, and hybrid bonding which is a combination of these can be used. In addition, low-temperature bonding using plasma activation and conventional thermocompression bonding can be used as bonding processes. Furthermore, bonding of semiconductor wafers of the same size, bonding of semiconductor wafers of different sizes, and methods of bonding multiple semiconductor chips spaced apart on a wafer (tiling) can be used. In addition, although the drive circuit integrated on the second substrate 152 is described as an example in this embodiment, the connections and structure are not limited to this.

[0056] In Figure 5B(1), the conductor layer 309 of the first substrate 151, which functions as both GND and reflector, is electrically connected to the conductor layer 1908 of the second substrate 152, which is GND. The first substrate 151 has a through via GND 1904 extending from the conductor layer 309 toward the junction surface BS and an electrode layer 1905 which is a GND terminal formed on the junction surface. In contrast, the conductor layer 1908 of the second substrate 152, which is GND, has a wiring via GND 1907 extending toward the junction surface BS and an electrode layer 1906 which is a GND terminal formed on the junction surface. The electrode layers 1905 and 1906, which are GND terminals on both sides, are electrically coupled at the junction and share the GND potential.

[0057] In Figure 5B(2), a MIM capacitor 320 is provided in the bias path of the first substrate 151. The MIM capacitor 320 is a capacitive structure formed by a conductor layer 325 connected to a conductor layer 303 that is connected to the conductor layer 507 of the receiving antenna and the conductor layer 1001 of the transmitting antenna via a power feed via 307, and a conductor layer 309 which is GND. However, any structure that forms capacitance may be an MIS (Metal-Insulator-Semiconductor) structure, and this is not limited to this. Also, the conductor layer 1908 which is GND of the second substrate 152 may be common with the GND layer and GND potential of the integrated circuit region 154 of the second substrate 152, or there may be multiple layers. Furthermore, the conductor layers 309 and 140 which are GND may be solid planes, and as an example to increase the bonding strength, dummy electrode layers 1909 and 1912 that are not connected to signal lines may be provided on the bonding surface BS. By widely distributing dummy electrode layers 1909 and 1912 in a solid pattern in areas where wiring electrodes are not required, the bonding strength can be increased, contributing to improved yield and reliability. Furthermore, such a solid ground configuration can reduce the influence of electromagnetic noise from the integrated circuit on the second substrate on the terahertz antenna of the first substrate 151.

[0058] The bias control will now be explained. Electrical connections are made to the conductor layer (electrode layer) 1910, which forms the electrode that is the bias terminal formed on the junction surface BS, in the following order: through via 305 connected to the conductor layer 303, wiring layer 135b provided in the opening 136b of the conductor layer 309 which is a reflector, and through via 137b formed on the semiconductor substrate 302. Similarly, on the second substrate 1903 side, the conductor layer 1911 which is the bias terminal formed on the junction surface BS is electrically connected to the MOS-FET 322, which is a transistor formed in the integrated circuit region 154. The MOS-FET 322 constitutes a common-gate amplifier circuit as the first-stage amplifier. The amplified signal is further amplified by a common-source amplifier circuit including MOS-FET 324. The common-gate amplifier circuit and the common-source amplifier circuit are coupled by an MIM capacitor 323 for AC coupling. The MIM capacitor 323 is just an example, and a configuration using the gate insulating film capacitance of the FET may also be used. MOS-FET1322 also functions as a bias control unit and is connected to the semiconductor substrate via MOS-FET322 to apply a bias voltage to the negative resistance element 300. Alternatively, the terminal for applying the bias voltage may be located on the second substrate 152, and the voltage may be supplied from an external source.

[0059] As in this embodiment, by joining a first substrate 151 having a transmitting and receiving active antenna and a second substrate 152 having an electronic integrated circuit using semiconductor bonding technology, it becomes unnecessary to integrate and mount the control circuit of the active antenna on the same plane. This reduces the space required for the control circuit to be placed on the same plane as the antenna, preventing the antenna characteristics from degrading due to coupling between the control circuit and the antenna. When bias control is individually controlled for each antenna, it is necessary to prepare each bias terminal individually, but in this embodiment, it is possible to easily connect to the integrated circuit area 154 with a through via 305. In this way, by wiring the control circuit on the back side of the first substrate 151, even when using an active antenna array as in the above-described embodiment, the number of antenna arrays can be increased without being affected by placement constraints. Since the electronic integrated circuit of the second substrate 152, which is the control circuit, is made using conventional CMOS technology, complex circuits can be configured for the detection circuit and signal processing circuit. This further expands the use of the terahertz wave receiving device using the active antenna according to this embodiment.

[0060] [Embodiment 5] This embodiment describes the case in which any of the antenna devices of the above embodiments is applied to a terahertz camera system (imaging system). The following description will be made with reference to Figure 6(a). The terahertz camera system 1100 has a transmitter 1101 that emits terahertz waves and a receiver (detection unit) 1102 that detects terahertz waves. Furthermore, the terahertz camera system 1100 has a control unit 1103 that controls the operation of the transmitter 1101 and the receiver 1102 based on an external signal, processes an image based on the detected terahertz waves, or outputs it to the outside. The antenna device of each embodiment may be the transmitter 1101 or the receiver 1102.

[0061] Terahertz waves emitted from the transmitter 1101 are reflected by the subject 1105 and detected by the receiver 1102. A camera system having such a transmitter 1101 and receiver 1102 can also be called an active camera system. In a passive camera system without a transmitter 1101, the antenna device of each embodiment described above can be used as the receiver 1102.

[0062] By using the antenna devices of each embodiment that are capable of beamforming, it becomes possible to improve the detection sensitivity of the camera system and obtain high-quality images.

[0063] [Embodiment 6] This embodiment describes the case where any of the antenna devices of the above embodiments are applied to a terahertz communication system (communication device). The following description will be made with reference to Figure 6(b). The antenna device can be used as the antenna 1200 of the communication system. As a communication system, various methods can be envisioned, from a simple ASK method to superheterodyne and direct conversion. A superheterodyne communication system, for example, includes an antenna 1200, an amplifier 1201, a mixer 1202, a filter 1203, a mixer 1204, a converter 1205, a digital baseband modulator / demodulator 1206, and local oscillators 1207 and 1208. In the case of a receiver, the terahertz wave received via the antenna 1200 is converted to an intermediate frequency signal by the mixer 1202, then converted to a baseband signal by the mixer 1204, and the analog waveform is converted to a digital waveform by the converter 1205. The digital waveform is then demodulated in the baseband to obtain a communication signal. In the case of a transmitter, after the communication signal is modulated, it is converted from a digital waveform to an analog waveform by the converter 1205, then frequency-converted via mixers 1204 and 1202, and output as a terahertz wave from the antenna 1200. The direct conversion communication system includes the antenna 1200, an amplifier 1211, a mixer 1212, a modulator / demodulator 1213, and a local oscillator 1214. In the direct conversion method, during reception, the received terahertz wave is directly converted into a baseband signal by the mixer 1212, and during transmission, the baseband signal to be transmitted is converted into a terahertz signal by the mixer 1212. The other configurations are the same as those of the superheterodyne method. The antenna devices according to each of the above embodiments can perform terahertz wave beamforming by electrical control of the chip alone. Therefore, radio wave alignment between the transceiver and receiver is possible. Therefore, by using the antenna devices of each embodiment that are capable of beamforming, it becomes possible to improve wireless quality such as the signal-to-noise ratio in a communication system, and to transmit large amounts of information over a wide coverage area at low cost.

[0064] [Other embodiments] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist.

[0065] For example, the above embodiment is described assuming that the carrier is an electron, but it is not limited to this, and holes may also be used. Furthermore, the substrate and dielectric materials can be selected according to the application, and semiconductor layers such as silicon, gallium arsenide, indium arsenide, and gallium phosphide, or resins such as glass, ceramic, polytetrafluoroethylene, and polyethylene terephthalate can be used.

[0066] Furthermore, although a square patch antenna is used as the terahertz wave resonator in the above-described embodiment, the shape of the resonator is not limited to this. For example, resonators with structures using patch conductors of polygonal shapes such as rectangles and triangles, or circular and elliptical shapes may be used.

[0067] Furthermore, the number of differential negative resistive elements integrated into the element is not limited to one, and a resonator containing multiple differential negative resistive elements may be used. The number of transmission lines is also not limited to one, and a configuration with multiple transmission lines may be used. By using the antenna device described in the above embodiment, it is possible to generate and detect terahertz waves.

[0068] Furthermore, in each of the embodiments described above, a double-barrier RTD made of InGaAs / AlAs grown on an InP substrate was described as the RTD. However, the present invention is not limited to these structures or material systems, and other structures and material combinations can also be used to provide the device. For example, an RTD having a triple-barrier quantum well structure or an RTD having four or more multi-barrier quantum wells may be used.

[0069] Furthermore, any of the following combinations may be used as materials for the RTD. • GaAs / AlGaAs and GaAs / AlAs, InGaAs / GaAs / AlAs formed on a GaAs substrate InGaAs / InAlAs, InGaAs / AlAs, InGaAs / AlGaAsSb formed on an InP substrate InAs / AlAsSb and InAs / AlSb formed on an InAs substrate • SiGe / SiGe formed on a Si substrate The above-mentioned structure and materials can be appropriately selected depending on the desired frequency and other factors.

[0070] Furthermore, a quantum cascade laser (QCL) structure having a multilayer semiconductor structure of several hundred to several thousand layers may be used as the semiconductor layer 100. In this case, the semiconductor layer 100 is a semiconductor layer containing the QCL structure. Alternatively, negative resistance elements such as Gunn diodes and INPAT diodes, which are commonly used in the millimeter-wave band, may be used as the semiconductor layer 100. Alternatively, high-frequency elements such as transistors terminated at one terminal may be used as the semiconductor layer 100. Suitable transistors include heterojunction bipolar transistors (HBTs), compound semiconductor layer FETs, and high electron mobility transistors (HEMTs). Alternatively, a differential negative resistance of a Josephson element using a superconductor layer may be used as the semiconductor layer 100.

[0071] The relationship between the active antenna array 11 and the control circuit 165 may take any form. The active antenna array 11 consists of multiple active antennas AA 11 ~AA mn The control circuit 165 includes multiple control elements AC 11 ~AC mn Includes. Multiple active antenna AA 11 ~AA mn Each of these controls multiple AC control elements. 11 ~AC mnIt may be controlled by signals from each of them. That is, one control element may control one active antenna. The degree of freedom in controlling the antenna can be increased. Note that the control circuit 165 includes a plurality of control elements AC 11 ~AC mn is not limited to the form including, and it is only necessary that the active antennas can be individually controlled.

[0072] Also, one control element may control a plurality of active antennas included in one group. In this case, the plurality of active antennas included in one group may be each row or each column of the plurality of active antennas AA 11 ~AA mn Moreover, the plurality of active antennas included in one group may be each region of a plurality of rows and a plurality of columns. By operating each of the plurality of active antennas, control becomes easy. Also, the output can be increased for each of the plurality of active antennas.

[0073] Furthermore, a plurality of control elements may control one active antenna. In this case, the degree of freedom of operation can be increased, such as when controlling one active antenna at each timing and when controlling a plurality of active antennas.

[0074] Also, when complex operations are desired, the above connection methods can be arbitrarily combined.

[0075] [Summary of Embodiments] Summarizing at least a part of the above embodiments, it is as follows.

[0076] (Item 1) An antenna device, An antenna array provided with a plurality of active antennas each including a semiconductor structure and an antenna that generate or detect electromagnetic waves, and a wiring electrically connected to the plurality of active antennas, a first substrate including the same; A second substrate is laminated with the first substrate and includes a control circuit for the antenna array, Equipped with, The first substrate and the second substrate are joined by a bonding surface. The control circuit is electrically connected to the antenna array via the wiring, The control circuit of the second substrate controls the operation of the plurality of active antennas of the first substrate. An antenna device characterized by the following features.

[0077] (Item 2) The antenna device according to item 1, characterized in that the control circuit is electrically connected to the semiconductor structure via the wiring.

[0078] (Item 3) The antenna device according to item 1 or 2, characterized in that the control circuit has a plurality of control elements, and each of the plurality of control elements is connected to each of the plurality of active antennas in a one-to-one relationship.

[0079] (Item 4) The antenna device according to any one of items 1 to 3, characterized in that the control circuit controls the plurality of active antennas by applying a signal of a predetermined voltage to the plurality of active antennas.

[0080] (Item 5) The antenna device according to any one of items 1 to 4, characterized in that the plurality of active antennas include a first conductor formed in a first layer of the first substrate and a second conductor formed in a second layer disposed between the first layer and the bonding surface, and having a larger area than the first conductor.

[0081] (Item 6) The antenna device according to item 5, characterized in that the second layer is provided between the bonding surface and the semiconductor structure.

[0082] (Item 7) The antenna device according to item 5 or 6, characterized in that the wiring includes a first via connecting the first conductor and a third layer provided between the first layer and the second layer.

[0083] (Item 8) The antenna device according to item 7, characterized in that the wiring includes a second via connecting the third layer and the control circuit through an opening provided in the second layer.

[0084] (Item 9) The antenna device according to item 8, characterized in that the lengths of the first and second vias are 1 / 10 or less of the wavelength of the electromagnetic wave.

[0085] (Item 10) The antenna device according to item 8 or 9, characterized in that the second via is positioned so as not to overlap with the first conductor in the stacking direction of the first substrate.

[0086] (Item 11) An antenna device according to any one of items 5 to 10, characterized in that it comprises a coupling line for electrically coupling adjacent active antennas, the length of which is set based on the electrical length of the electromagnetic wave in the coupling line.

[0087] (Item 12) The antenna device according to item 11, characterized in that a third via is provided through an opening in the second layer for electrically connecting the coupling wire and the control circuit.

[0088] (Item 13) The antenna device according to item 12, characterized in that the length of the third via is 1 / 10 or less of the length of the electrical length of the electromagnetic wave in the third via.

[0089] (Item 14) A third layer is provided between the first layer and the second layer. The antenna device according to any one of items 11 to 13, characterized in that the coupling line is connected to wiring provided in the third layer by a fourth via.

[0090] (Item 15) The antenna device according to item 14, characterized in that the fourth via is positioned at a location different from the position of the node of the standing wave of the electromagnetic wave in the coupling line.

[0091] (Item 16) The antenna device according to item 14, characterized in that the fourth via is positioned at the node of the standing wave of the electromagnetic wave in the coupling line.

[0092] (Item 17) The antenna device according to any one of items 5 to 16, characterized in that the bonding surface is disposed between the second layer and the control circuit.

[0093] (Item 18) The antenna device according to any one of items 5 to 17, characterized in that a fourth layer including a third conductor having a larger area than the first conductor is provided between the bonding surface and the control circuit.

[0094] (Item 19) The antenna device according to item 18, characterized in that the third conductor is a solid plane.

[0095] (Item 20) The antenna device according to any one of items 1 to 19, characterized in that the thickness of the first substrate is 1 / 10 or less of the wavelength of the electromagnetic wave.

[0096] (Item 21) The antenna device according to any one of items 1 to 20, characterized in that the plurality of active antennas in the antenna array are arranged in a matrix.

[0097] (Item 22) The antenna device according to any one of items 1 to 21, characterized in that the plurality of active antennas in the antenna array are arranged at intervals less than or equal to the wavelength of the electromagnetic wave.

[0098] (Item 23) The antenna device according to any one of items 1 to 22, characterized in that the aforementioned antenna is a patch antenna.

[0099] (Item 24) The antenna device according to any one of items 1 to 23, characterized in that the semiconductor structure includes a negative resistance element.

[0100] (Item 25) The antenna device according to item 24, characterized in that the negative resistive element is a resonant tunneling diode.

[0101] (Item 26) The antenna device according to any one of items 1 to 25, characterized in that the control circuit is a bias control circuit for supplying a bias signal to the semiconductor structure.

[0102] (Item 27) The antenna device according to item 11, characterized in that the control circuit is a phase control circuit for controlling the phase of electromagnetic waves output to the antenna array.

[0103] (Item 28) The antenna device according to item 27, characterized in that the phase control circuit is connected to the coupling line at the position of a node of a standing wave that is present on the coupling line at the frequency of the electromagnetic wave.

[0104] (Item 29) The antenna device according to item 27, characterized in that the phase control circuit has an impedance variable that adjusts the impedance of the coupling line with respect to the frequency of the electromagnetic wave.

[0105] (Item 30) The antenna device according to any one of items 1 to 29, characterized in that the control circuit includes an oscillator circuit that oscillates electromagnetic waves with a frequency that is an integer fraction of the frequency of the electromagnetic waves.

[0106] (Item 31) The antenna device according to any one of items 1 to 30, characterized in that the plurality of active antennas comprises a first active antenna for transmission and a second active antenna for reception.

[0107] (Item 32) The antenna device according to any one of items 1 to 31, characterized in that the electromagnetic wave is an electromagnetic wave in the terahertz band.

[0108] (Item 33) An antenna device as described in any one of items 1 to 32, The transmitting unit that emits the aforementioned electromagnetic waves, The receiving unit for detecting the electromagnetic waves, A communication device characterized by having the following features.

[0109] (Item 34) An antenna device as described in any one of items 1 to 32, A transmitting unit that emits the aforementioned electromagnetic waves toward the subject, A detection unit for detecting the electromagnetic waves reflected by the subject, An imaging system characterized by having the following features. [Explanation of Symbols]

[0110] AA Active antenna, 100 Semiconductor (RTD), CL Transmission line (coupling line), VZ Impedance variable, 101 Upper conductor layer of patch antenna, 102 Bias wiring layer, 103 Via (mesa), 104-106 Dielectric layer, 107 Via (bias), 108 Wiring layer, 109 GND layer, 110 Substrate, 111 Conductor layer, 112 Dielectric layer, 113 Conductor layer (MIM), 114 Via (MIM), 115 Conductor layer (VL), 117 Conductor layer (penetrating reflector), 124 Via (Z control), 125 Wiring layer (Z control), 126 MIM capacitance, 127 Resistive layer (TiW), 128 Conductor layer (D), 130 Via (master synchronization line), 131 Insulator layer, 132 Insulator layer, 133 134 Insulator layer, 135 Second semiconductor substrate, 136 Wiring layer (reflector opening), 137 Opening (reflector), 137 Through via (first), 138 Electrode layer (junction, first), 139 Electrode layer (junction, second), 140 GND layer (shield), 141 Wiring via (second), 142 Opening (shield), 143 Wiring layer (power), 144 GND layer (junction, first), 145 GND layer (junction, second), 146 GND via (first), 147 GND via (second), 151 First substrate, 152 Second substrate, 154 Integrated circuit area, 155 MIM capacitance (second), 162 Upper electrode layer, 163 Semiconductor structure layer, 164 Lower electrode layer

Claims

1. 1. An antenna device, comprising: A first substrate including an antenna array having a plurality of active antennas, each of which includes a semiconductor structure and an antenna for generating or detecting an electromagnetic wave, and wiring electrically connected to the plurality of active antennas; a second substrate laminated on the first substrate and including a control circuit for the antenna array; Equipped with the first substrate and the second substrate are joined by a joining surface, the control circuit is electrically connected to the antenna array via the wiring; the control circuit of the second substrate controls the operation of the plurality of active antennas of the first substrate; the antenna includes a first conductor formed on a first layer and a second conductor formed on a second layer; An antenna device, characterized in that, in a plan view, the semiconductor structure is disposed between the first layer and the second layer.

2. The antenna device according to claim 1 , wherein the control circuit is electrically connected to the semiconductor structure via the wiring.

3. The control circuit has a plurality of control elements, 2. The antenna device according to claim 1, wherein each of the plurality of control elements is connected to each of the plurality of active antennas in a one-to-one relationship.

4. 2. The antenna device according to claim 1, wherein the control circuit controls the plurality of active antennas by applying a signal of a predetermined voltage to the plurality of active antennas.

5. The antenna device described in claim 1, characterized in that the first layer is formed on the first substrate, and the second layer includes a second conductor arranged between the first layer and the joining surface and having an area larger than the first conductor.

6. 6. The antenna device according to claim 5, wherein the second layer is provided between the junction surface and the semiconductor structure.

7. 6. The antenna device according to claim 5, wherein the wiring includes a first via that connects the first conductor and a third layer provided between the first layer and the second layer.

8. 8. The antenna device according to claim 7, wherein the wiring includes a second via that connects the third layer and the control circuit through an opening provided in the second layer.

9. 9. The antenna device according to claim 8, wherein the length of the first and second vias is equal to or less than 1 / 10 of the wavelength of the electromagnetic wave.

10. The antenna device according to claim 8 , wherein the second via is disposed at a position not overlapping with the first conductor in a stacking direction of the first substrate.

11. 6. The antenna device according to claim 5, further comprising a coupling line that electrically couples adjacent active antennas, the length of the coupling line being set based on an electrical length of the electromagnetic wave in the coupling line.

12. 12. The antenna device according to claim 11, further comprising a third via hole provided through the second layer to electrically connect the bond line and the control circuit.

13. 13. The antenna device according to claim 12, wherein the length of the third via is equal to or less than 1 / 10 of the electrical length of the electromagnetic wave in the third via.

14. a third layer is provided between the first layer and the second layer; The antenna device according to claim 11, wherein the bonded wire is connected to a wiring provided on the third layer by a fourth via.

15. The antenna device according to claim 14, wherein the fourth via is disposed at a position different from a node position of the standing wave of the electromagnetic wave in the coupled line.

16. The antenna device according to claim 14, wherein the fourth via is disposed at a node of the standing wave of the electromagnetic wave in the coupled line.

17. 6. The antenna device according to claim 5, wherein the bonding surface is disposed between the second layer and the control circuit.

18. 6. The antenna device according to claim 5, further comprising a fourth layer including a third conductor having an area larger than that of the first conductor, the fourth layer being provided between the joint surface and the control circuit.

19. 20. The antenna device according to claim 18, wherein the third conductor is a solid pattern.

20. 2. The antenna device according to claim 1, wherein the thickness of the first substrate is equal to or less than 1 / 10 of the wavelength of the electromagnetic wave.

21. 2. The antenna device according to claim 1, wherein the plurality of active antennas are arranged in a matrix in the antenna array.

22. 2. The antenna device according to claim 1, wherein the plurality of active antennas in the antenna array are arranged at intervals equal to or less than the wavelength of the electromagnetic waves.

23. 2. The antenna device according to claim 1, wherein the antenna is a patch antenna.

24. 2. The antenna device of claim 1, wherein the semiconductor structure comprises a negative resistance element.

25. 25. The antenna device according to claim 24, wherein the negative resistance element is a resonant tunneling diode.

26. 2. The antenna device according to claim 1, wherein the control circuit is a bias control circuit for providing a bias signal to the semiconductor structure.

27. 12. The antenna device according to claim 11, wherein the control circuit is a phase control circuit for controlling the phase of an electromagnetic wave output to the antenna array.

28. 28. The antenna device according to claim 27, wherein the phase control circuit is connected to the coupled line at a node of a standing wave that exists in the coupled line at the frequency of the electromagnetic wave.

29. 28. The antenna device according to claim 27, wherein the phase control circuit has an impedance variator that adjusts the impedance of the coupling line at the frequency of the electromagnetic wave.

30. 2. The antenna device according to claim 1, wherein the control circuit includes an oscillation circuit that oscillates an electromagnetic wave having a frequency that is an integer fraction of the frequency of the electromagnetic wave.

31. 2. The antenna device according to claim 1, wherein the plurality of active antennas comprises a first active antenna for transmitting and a second active antenna for receiving.

32. 2. The antenna device according to claim 1, wherein the electromagnetic wave is an electromagnetic wave in the terahertz band.

33. An antenna device according to any one of claims 1 to 32, A transmitter that radiates the electromagnetic wave; A receiving unit that detects the electromagnetic wave; A communication device comprising:

34. An antenna device according to any one of claims 1 to 32, a transmitter that radiates the electromagnetic wave toward a subject; a detection unit that detects the electromagnetic wave reflected by the subject; An imaging system comprising:

Images