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 technology]

[0002] In recent years, the development of semiconductor devices that output or detect electromagnetic waves such as terahertz waves has accelerated due to the frequency band used in the next-generation communication standard 6G. Active antennas that integrate resonant tunneling diodes (RTDs) and antennas are expected to be high-frequency devices that operate at room temperature in the frequency range around 1 THz. Patent Document 1 discloses an active antenna array for terahertz waves using RTDs. Such high-frequency devices use materials such as indium gallium arsenide (InGaAs) with high electron mobility and are formed on semiconductor substrates such as indium phosphide (InP). Meanwhile, the control circuit for the high-frequency device is formed on a semiconductor substrate using semiconductor materials such as silicon (Si). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6373010 Summary of the Invention [Problem to be solved by the invention]

[0004] When the substrate on which the high-frequency elements are formed and the substrate on which the control circuit is formed are different types of substrates, it is necessary to fabricate each substrate separately. Here, depending on the connection method between the substrate on which the high-frequency elements and the control circuit are formed, inductance due to the wiring length may cause signal delay or signal loss, making high-speed signal control impossible. Furthermore, 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 the high-frequency elements are formed and a substrate on which the control circuit is formed, the connection between these substrates has not been thoroughly considered.

[0005] An object of the present invention is to provide a suitable antenna device having multiple substrates. [Means for solving the problem]

[0006] In order to achieve the above object, an antenna device according to the present invention comprises: An antenna device, a first substrate including an antenna array provided with a plurality of active antennas, each of which includes a semiconductor structure and an antenna that generate or detect electromagnetic waves, 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 bonded together 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. death, the antenna includes a first conductor formed on a first layer and a second conductor formed on a second layer; In a plan view, the semiconductor structure is disposed between the first layer and the second layer. It is characterized by: [Effects of the Invention]

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

[0008] [Figure 1] (a) is a block diagram showing the antenna device 10, (b) is a schematic top view showing the first substrate 151 of the antenna device 10, (c) is a schematic top view showing the second substrate 152 of the antenna device 10, and (d) is a schematic top view showing the second substrate 152 of the antenna device 10. [Figure 2A] 1 is a top view of an antenna device according to a first embodiment. [Figure 2B] (1) is an AA' cross-sectional view of the antenna device according to embodiment 1, (2) is a BB' cross-sectional view of the antenna device according to embodiment 1, and (3) is a CC' cross-sectional view of the antenna device according to embodiment 1. [Figure 3A] FIG. 10 is a top view of an antenna device according to a second embodiment. [Figure 3B] (1) is an AA' cross-sectional view of the antenna device of embodiment 2, (2) is a BB' cross-sectional view of the antenna device of embodiment 2, and (3) is a CC' cross-sectional view of the antenna device of embodiment 2. [Figure 4A] FIG. 10 is a top view of an antenna device according to a third embodiment. [Figure 4B] (1) is an A-A' cross-sectional view of the antenna device of embodiment 3, (2) is a B-B' cross-sectional view of the antenna device of embodiment 3, and (3) is a CC' cross-sectional view of the antenna device of embodiment 3. [Figure 5A] FIG. 10 is a top view of an antenna device according to a fourth embodiment. [Figure 5B] (1) is an A-A' cross-sectional view of the antenna device of embodiment 4, (2) is a B-B' cross-sectional view of the antenna device of embodiment 4, and (3) is a C-C' cross-sectional view of the antenna device of embodiment 4. [Figure 6] 1A is a diagram illustrating an example of the configuration of a camera system using an antenna device, and FIG. 1B is a diagram illustrating an example of the configuration of a communication system using an antenna device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] In the following explanation, the antenna device will be described as being used as a receiving device for detecting terahertz waves, but the antenna device can also be used as a transmitting device for emitting terahertz waves. Here, terahertz waves refer to electromagnetic waves within a frequency range of 10 GHz to 100 THz, for example, 30 GHz to 30 THz.

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

[0012] In FIG. 1(a), the antenna device 10 includes n active antennas AA1 to AA n and a second substrate 152 having 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 mnEach of the active antenna arrays 11 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 called 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 an m×n (m≧2, n≧2) matrix with m antennas vertically and n antennas horizontally.

[0014] The second substrate 152 includes an active antenna AA 11 ~AA mn The control circuit 165 includes a control unit (control circuit) 165 for individually controlling the control elements AC 11 ~AC mn In this embodiment, the control unit AC 11 ~AC mn is an active antenna AA 11 ~AA mn The active antenna AA 11 ~AA mn In this case, the control unit AC of the second substrate 152 is arranged in a matrix. 11 ~AC mn is the corresponding antenna AA 11 ~AA mn In this case, the corresponding antenna AN mn and control unit AC mn 1(c), the second substrate 152 includes a bias control section 12, a phase control section 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 disposed in the center of the second substrate 152. The control circuit 165 includes electronic integrated circuits 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] 1(d), the second substrate 152 may include a bias control unit 12, a vertical shift register 14, a horizontal shift register 15, and an ADC / DAC 16, and may be connected to a control circuit 165 disposed in the center of the second substrate 152. In this case, the control circuit 165 includes a semiconductor structure that is an electronic integrated circuit, such as a switch for switching a matrix controlled by a signal from the shift register, a transistor for controlling a bias signal to the semiconductor layer 100, and a transistor for controlling the phase and output of each antenna. When an active antenna is used as a receiver, the control circuit 165 may include a preamplifier or a low-noise amplifier. The control circuit 165 is a transistor-based electronic integrated circuit, and silicon (Si) devices such as CMOS (Complementary Metal Oxide Semiconductor) of 90 nm or later and FinFET (Fin Field-Effect Transistor) of 10 nm or later can be used. In addition, electronic integrated circuits based on transistors such as silicon germanium (SiGe)-BiCMOS, SiGe-HBT (heterojunction bipolar transistor), indium gallium arsenide (InGaAs) / indium phosphide (InP)-high electron mobility transistor (HEMT), InGaAs / InP-HBT, and gallium nitride (GaN)-HEMT, which are compound semiconductor devices operating in the terahertz band, can also be used. Here, BiCMOS is a semiconductor circuit that combines a bipolar circuit and a CMOS circuit. Note that the following embodiments will be described using Si-MOS-FETs as transistors, but the scope of the present invention is not limited to this.

[0016] (3x3 active antenna array) 2A and 2B are diagrams showing the active antenna array 11 portion of the antenna device 10. As shown in FIG. 2A, a square patch antenna is used as the antenna, and nine patch antennas are arrayed in a 3×3 matrix. Each of the active antennas AA1 to AA9 integrates at least one antenna and a semiconductor layer 100 that serves as an oscillation source, and generates an oscillation frequency f THz The active antenna radiates terahertz waves in a direction perpendicular to the surface of the substrate. The semiconductor layer 100 of each active antenna includes a semiconductor structure for generating or detecting terahertz waves, and in this embodiment, an example using a resonant tunneling diode (RTD) will be described. Note that the semiconductor layer 100 is not limited to an RTD, and may be any semiconductor having electromagnetic wave gain or carrier nonlinearity (nonlinearity of current accompanying voltage change in current-voltage characteristics) for terahertz waves. Note that the bias control unit 12 shown in FIG. 1 is a power supply for controlling a 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, the active antennas are electrically connected to each other by coupling lines CL, which are transmission lines. The coupling lines CL are transmission lines that connect the antennas at a frequency f THz For example, the active antennas AA1 and AA2 are connected by a coupling line CL 12 and are connected by a bond line CL 12 In the example of the 3x3 array shown in Figure 2A, two coupled lines CL, which are microstrip lines, are used to synchronize the active antennas AA1 and AA4 in the horizontal direction. 14a and CL 14b are connected. 14a and CL 14b are the variable impedance devices VZ 14a and VZ 14bSimilarly, a coupling line CL is connected between the active antennas AA1 and AA2 for vertical synchronization. 12 and the variable impedance transformer VZ connected between them. 12a will be placed.

[0018] (Active antenna configuration) 2B(1) to 2B(3) are cross-sectional views of the active antenna array 11 taken along lines AA', BB', and CC'. The active antenna AA functions 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) equal to or less than the wavelength of the terahertz waves to be detected or generated, or at an integer multiple of that wavelength. The active antenna AA includes at least a conductor layer (antenna layer, upper conductor layer) 101 (AA1) that is the upper conductor of the patch antenna, a conductor layer 109 that also serves as a GND layer and a reflector layer, and a semiconductor layer 100 disposed therebetween. The semiconductor layer 100 uses a resonant tunneling diode (RTD) as the semiconductor structure 162. The 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 an upper conductor of the bonded line CL. In addition, a conductor layer 102 that forms a bias wiring is disposed between the conductor layer 101 and the conductor layer 109, 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 a wiring 108 and a via 107. In addition, the conductor layer 109, which serves as a GND layer, is grounded.

[0019] As shown in (1) of FIG. 2B , the semiconductor layer 100 includes a lower electrode layer 164, a semiconductor structure 162, and an upper electrode layer 163 stacked in this order 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 the lower electrode layer 164 also serve as electrode layers for connecting contact electrodes (ohmic or Schottky) above and below the semiconductor structure 162 with 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 the lower electrode layer 164 can be made of metal materials known as ohmic electrodes or Schottky electrodes (such as Ti, Pd, Au, Cr, Pt, AuGe, Ni, TiW, Mo, ErAs), 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 a via 103 connecting the conductor layer 101 and the semiconductor layer 100. To apply a control signal to the semiconductor layer 100, a conductor layer 102 and a via 107, which form bias wiring individually provided for each antenna, a MIM (Metal Insulator Metal) capacitor 126, and a resistive layer 127 are connected to the active antenna AA1. The MIM capacitor 126 is a capacitive element in which metal is sandwiched between insulator layers and is arranged to suppress low-frequency parasitic oscillation caused by the bias circuit. The MIM capacitor 126 in this embodiment has a structure in which a portion of the dielectric layer 106 is sandwiched between the conductor layer 113 and the conductor layer 109 (GND).

[0021] (antenna array) To increase the gain of the active antenna array 11, it is considered to arrange multiple active antennas AA1 to AA9 in an array. Each active antenna includes a semiconductor layer 100 containing an RTD, as described above. Mutual injection synchronization between the active antennas increases the gain of the array antenna. To synchronize the multiple active antennas AA1 to AA9, a coupling line CL is required to couple adjacent antennas. Each active antenna is connected to each coupling line by capacitive coupling. The length of the coupling line CL is designed to satisfy phase matching conditions in either or both the horizontal direction (magnetic field direction, H direction) and the vertical direction (electric field direction, E direction) when connecting adjacent antennas with a coupling line. Note that the present invention is applicable not only to antennas that radiate horizontally and vertically polarized waves as described above, but also to antennas that radiate circularly polarized waves. For example, circular polarization can be radiated by forming a notch in the conductor layer 101 of a patch antenna, rather than a square, in a rectangular shape. Alternatively, an antenna that radiates circularly polarized waves other than a patch antenna may be applied.

[0022] In one example, the coupling line is designed to have a length such that the electrical length between the RTDs of adjacent antennas is an integer multiple of 2π. For example, the coupling line CL extending in the horizontal direction 14 is the length at which the electrical length between the semiconductor layers 100 of the active antennas AA1 and AA4 is 4π. 12 is the length at which the electrical length between the semiconductor layers 100 of the active antennas AA1 and AA2 is 2π. Here, the electrical length is the wiring length taking into consideration the propagation speed of high frequency waves propagating within the coupled line. With this design, the semiconductor layers 100 of each active antenna AA1 to AA9 are mutually injection locked in positive phase. The error in the length range is ±1 / 4π.

[0023] Between the adjacent active antennas AA1 and AA2 is connected a variable impedance transformer VZ for adjusting the impedance of the coupled line CL1. 12In this embodiment, a MOS-FET, which is advantageous in terms of circuit integration and cost reduction, is used as the variable impedance device VZ. The configuration is such that a first substrate 151, on which an antenna array for transmitting and receiving terahertz waves and a semiconductor layer 100 made of a compound semiconductor (semiconductor structure) are integrated, is bonded at a bonding surface BS to a second substrate 152 containing a CMOS integrated circuit for controlling the antenna array. This configuration is realized by stacking the compound semiconductor antenna substrate containing the antenna array and the Si integrated circuit substrate using semiconductor stacking technology.

[0024] (Explanation of laminated structure) As shown in (1) of FIG. 2B , the semiconductor layer 100 includes a lower electrode layer 164, a semiconductor structure 162, and an upper electrode layer 163 stacked in this order 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 the lower electrode layer 164 also serve as electrode layers for connecting contact electrodes (ohmic or Schottky) above and below the semiconductor structure 162 with 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 the lower electrode layer 164 can be made of metal materials known as ohmic electrodes or Schottky electrodes (such as Ti, Pd, Au, Cr, Pt, AuGe, Ni, TiW, Mo, ErAs), or semiconductors doped with impurities.

[0025] Each active antenna AA is composed of the antenna's conductor layer 101, semiconductor layer 100, conductor layer 109 (reflector), dielectric layers 104 and 105, and via 103 connecting the conductor layer 101 and semiconductor layer 100. To apply a control signal to the semiconductor layer 100, the active antenna AA is connected to a conductor layer 102 and via 107, which form bias wiring individually provided for each active antenna, an MIM capacitor 126, and a resistive layer 127, as shown in (2) and (3) of FIG. 2B. The MIM capacitor 126 is a capacitive element formed by sandwiching metal between insulator layers, and is arranged to suppress low-frequency parasitic oscillation caused by the bias circuit. The active antennas AA1 to AA9 are connected by a transmission line CL for synchronizing the antennas at terahertz frequencies.

[0026] A bonding surface BS is provided on the bottom surface of the first substrate 151 on which the antenna array and compound semiconductor are integrated, and the first substrate 151 is bonded to a second substrate 152 including an integrated circuit via the bonding surface BS. Here, "bonded" 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 includes a semiconductor substrate as a base material and an integrated circuit region in which a drive circuit is formed. The two different types of substrates 151 and 152 can be bonded by metal bonding such as CuCu bonding, SiO X / SiO X Bonding is performed using insulator bonding such as SiO2 bonding, adhesive bonding using adhesives such as BCB, and hybrid bonding, which is a combination of these. Bonding processes include low-temperature bonding using plasma activation and conventional thermocompression bonding. Also used are bonding of semiconductor wafers of the same size, bonding of semiconductor wafers of different sizes, and bonding of multiple semiconductor chips spaced apart on a wafer (tiling).

[0027] In the active antenna array 11, the mesa structure of the semiconductor layer 100 is embedded in a dielectric layer 105 so as to cover the periphery. The surface of the dielectric layer 105 on the junction surface BS side is flattened, and a conductor layer 109 serving as a reflector is provided on this flattened surface. The dielectric layer 105 serves as a dielectric material constituting the antenna, and also serves as a flattening film in the manufacturing process of transferring the mesa structure of the semiconductor layer 100 to a heterogeneous substrate. The dielectric layer 105 may be made of, for example, silicon oxide (SiO X ), silicon nitride (SiN X Inorganic insulating materials such as silicon oxynitride (SiON), silicon dioxide containing carbon (SiOC), and silicon carbide (SiC) are used. The active antenna array 11 is composed of an antenna region 52 (inside the conductor layer 101, which is the upper conductor of the patch antenna) where the antenna is provided, and a peripheral region 51 outside the antenna region where 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, while 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 the region that does not overlap with the conductor layer 101, which is the upper conductor of the patch antenna, and is more than 1 / 10 of the wavelength of the terahertz wave away from the conductor layer 101. In other words, the antenna region 52 is a region that includes the near field of the terahertz wave, and the peripheral region 51 is a region that does not include the near field of the terahertz wave.

[0028] On the side of first substrate 151 opposite second substrate 152, conductor layer 109, dielectric layer 105, dielectric layer 104, and dielectric layer 112 are laminated in this order. Vias 103, vias 107, and vias 124, and conductor layers 101, 102, and 111 connected thereto, are formed in dielectric layer 105 and dielectric layer 104, respectively. The bonding surface BS side of first substrate 151 with second substrate 152 is disposed in a position facing semiconductor layer 100, with conductor layer 109, which serves as a reflector, interposed therebetween. Conductor layer 102, which serves as a wiring layer, is provided between conductor layer 101, which serves as an antenna layer, and conductor layer 109, which serves as a reflector layer. The planarized surface of the dielectric layer 105 of the first substrate 151 facing the second substrate 152 is laminated with the conductor layer 109 and the insulator layer 131 in this order, with the through via 137 and the bonding electrode layer 138 formed in the insulator layer 131. The insulator layer 131 and the electrode layer 138 are planarized at the bonding surface BS, and the bonding process is performed with the flat bonding surface BS exposed. The second substrate 152 is laminated with the semiconductor substrate 134, which is the base material, the insulator layer 133, the conductor layer 140, and the insulator layer 132 in this order, and the via 141 and the bonding electrode layer 139 are formed in the insulator layer 132. The insulator layer 132 and the electrode layer 139 are planarized at the bonding surface BS, and the bonding process is performed with the flat bonding surface BS exposed. Therefore, the bonding surface BS is provided between the conductor layer 109, which is the reflector, and the second substrate 152, which is the control circuit board. In this configuration, the antenna and the control circuit are separated, which makes it possible to reduce noise caused by radio wave interference between the active antenna array that operates at terahertz frequencies and the control circuit that operates at RF frequencies. The insulator layers 131 to 134 are made of silicon oxide (SiO X ), silicon nitride (SiN X The insulator layer 131 may be formed using an inorganic insulating material such as silicon oxynitride (SiON), silicon oxide containing carbon (SiOC), silicon carbide (SiC), etc. Alternatively, the insulator layer 131 may be formed using a compound semiconductor substrate.

[0029] FIG. 2B (1) is an A-A' cross-sectional view of the antenna array 41. The transmission line CL and the conductor layer 109, which is a reflector, of the first substrate 151, on which compound semiconductors are integrated, are electrically connected to a phase control transistor TRa (MOS-FET) and a conductor layer 140, respectively, arranged 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 the via 124 formed in the dielectric layer 104 and the dielectric layer 105, and to the wiring layer 135c provided in the opening 136c of the dielectric layer 104. Furthermore, the wiring layer 135c is electrically connected in this order to the 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. The transistor TR formed in the integrated circuit region of the second substrate 152 is connected in this order to the 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 bonding surface BS, thereby establishing electrical continuity between the transmission line CL of the antenna array and the transistor TRa of the integrated circuit region 154, allowing a control signal to be applied. 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] FIG. 2B(1) is an A-A' cross section of the active antenna array 11. The transmission line CL and the conductor layer 109, which is a reflector, of the first substrate 151, on which compound semiconductors are integrated, are electrically connected to a phase control transistor TRa (MOS-FET) arranged in the integrated circuit region 154 of the second substrate 152 and a conductor layer 140 corresponding to the second GND. 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 bonding surface BS in the following order: a via 124 formed in the dielectric layers 104 and 105; a wiring layer 135c provided in the opening 136c of the dielectric layer 104; a through via 137c provided in the insulator layer 131; and a bonding electrode layer 138c. The transistor TR formed in the integrated circuit region 154 of the second substrate 152 is connected to the bonding surface BS in the following order: a via 141c formed in the integrated circuit region 154; and a 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 bonding surface BS, so that the transmission line CL of the antenna array and the transistor TRa of the integrated circuit region 154 are conductive and can 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.

[0031] Similarly, the conductor layer 109, which is a reflector for the antenna of the first substrate 151, is electrically connected to the through via 137g provided in the insulator layer 131 and the bonding electrode layer 138g in this order, and reaches the bonding surface BS. The conductor layer 140, which is the GND of the second substrate 152, is electrically connected to the via 141g formed in the insulator layer 132 and the bonding electrode layer 139g in this order, and reaches the bonding surface BS. The electrode layer 138g of the first substrate 151 and the electrode layer 139g of the second substrate 152 are electrically connected at the bonding surface BS, so that the GND potential of both substrates is shared. For example, to increase 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 distributing the GND electrode layers 138g and 139g and the dummy electrode layers 138d and 139d widely over the entire bonding surface BS, the influence of electromagnetic noise caused by the integrated circuit on the second substrate 152 on the terahertz antenna on the first substrate 151 can be reduced.

[0032] Similarly, conductor layer 109, which is a reflector in the antenna of first substrate 151, is electrically connected in this order to through via 137g provided in insulator layer 131 and bonding electrode layer 138g, and reaches bonding surface BS. Conductor layer 101, which is the upper conductor, and conductor layer 109, which has a larger area than the upper conductor and is formed on conductor layer 101 and functions as GND, function as a patch antenna that resonates with terahertz waves. Furthermore, conductor layer 140, which is the GND of second substrate 152, is connected in this order to via 141g formed in integrated circuit region 154 and bonding electrode layer 139g, and reaches bonding surface BS. Electrode layer 138g of first substrate 151 and electrode layer 139g of second substrate 152 are electrically connected at bonding surface BS, so that both substrates share the GND potential. By disposing conductor layer 140 as a second GND, separate from conductor layer 109, which serves as a reflector and a first GND, noise due to radio wave interference between an active antenna array operating at terahertz frequencies and a control circuit operating at RF frequencies can be reduced. To enhance the noise reduction effect, conductor layers 109 and 140, which serve as GNDs, preferably have a solid pattern. To increase bonding strength, dummy electrode layers 138b and 139b not connected to signal lines may be provided on bonding surface BS. Widely distributing dummy electrode layers 138b and 139b in areas where wiring electrodes are not required increases bonding strength, contributing to improved yield and reliability. Furthermore, by distributing GND electrode layers 138g and 139g and dummy electrode layers 138b and 139b widely on bonding surface BS, the influence of electromagnetic noise on the antenna of first substrate 151 due to the integrated circuit on the second substrate can be reduced.

[0033] 2B (2) is a B-B' cross-sectional view of the antenna array 41. The conductor layer 102, which forms bias wiring connected to the compound semiconductor layer of the first substrate 151, is electrically connected to a transistor TRb (MOS-FET) that is a bias control circuit provided in the integrated circuit region of the second substrate 152. The conductor layer 102 is electrically connected to a via 107 formed in the dielectric layer 105, a wiring layer 135b provided in an opening 136b of the conductor layer 109 that serves as a reflector, a through via 137b provided in the insulator layer 131, and a bonding electrode layer 138b in this order. As a result, the wiring layer 102 reaches the bonding surface BS. Similarly, the transistor TRb formed in the integrated circuit region of the second substrate 152 is connected to a via 141b formed in the integrated circuit region and a bonding electrode layer 139b in this order, and reaches the bonding surface BS. 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 brings the bias wiring layer 102 of the antenna array and the transistor TRa in the integrated circuit region into conduction, making it possible to apply individual control signals to each antenna.

[0034] FIG. 2B(2) shows the B-B' cross section of the active antenna array 11. The bias wiring layer 102 connected to the compound semiconductor layer of the first substrate 151 is electrically connected to a transistor TRb (MOS-FET) that 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 bonding surface BS in the following order: the via 117, the wiring layer 135b provided in the opening 136b of the conductor layer 109 that serves as the reflector, the through via 137b provided in the insulator layer 131, and the bonding electrode layer 138b. Here, the opening 136 and the electrodes (the wiring layer 135, the through via 137, and the 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 opening 136 of the reflector and the bonding member in a position that does not overlap with the antenna region, radiation efficiency and noise reduction effects can be expected. However, it is not necessarily required to place them in the peripheral region 51. For example, if the length is sufficiently smaller than the electrical length of the electromagnetic wave expected to propagate through the opening 136, the wiring layer 135, and the through via 137 (typically 1 / 10 or less of the electrical length λ), the effect on the antenna can be ignored. In this case, the opening 136, the wiring layer 135, and the through via 137 may be placed within the antenna region.

[0035] Similarly, transistor TRb formed in integrated circuit region 154 of second substrate 152 is electrically connected to bonding surface BS through via 141b formed in integrated circuit region 154 and bonding electrode layer 139b in that order. Electrode layer 138b of first substrate 151 and electrode layer 139b of second substrate 152 are electrically connected at bonding surface BS, thereby establishing electrical connection between bias wiring layer 102 of the antenna array and transistor TRa in integrated circuit region 154. This allows control signals to be applied individually to each antenna.

[0036] The transistor TRa, which is a phase control circuit, adjusts the impedance of the transmission line CL by variable resistance or switch operation by connecting the source and drain of a MOS-FET to the middle of the transmission line CL. The phase control transistor TRa can also be used as a variable capacitor by connecting the gate and source. The MOS-FET of the transistor TRa, which is a bias control circuit, also functions as a bias control unit and operates as a switching regulator to supply a bias signal to the semiconductor layer 100. As an alternative configuration, a terminal for applying a bias signal may be provided separately on the second substrate 152, the transistor TRa operates as an analog switch, and a voltage may be supplied from outside the second substrate 152.

[0037] (Device operation) The active antenna array 11 shown in Figures 2A and 2B uses hybrid couplers as impedance variable devices. The active antenna array 11 includes four hybrid couplers VZ 1245 , V.Z. 2356 , V.Z. 4578 , and VZ 5689 For example, active antennas AA1, AA2, AA4, and AA5 are connected by two coupling wires CL 14b and CL 25a Hybrid coupler VZ placed between 1245 Hybrid coupler VZ 1245 are four variable impedance devices VZ 12b , V.Z. 45a , V.Z. 14b , and VZ 25a Of these, the variable impedance transformer VZ 12b and VZ 45a is two bond lines CL 14b and CL 25a are connected vertically, and the ON / OFF switch turns on / off the connecting wire CL 14b and CL 25a The variable impedance VZ 14b is the connecting line CL14b The variable impedance VZ 25a is the bond line CL 25a It is placed in the middle of the two and acts as a switch to switch the coupling between adjacent antennas. 1245 It is possible to control the multiplexing within the ports to generate a phase difference between them. It is also possible to change the electrical length of the coupling line CL simply by changing the impedance of the variable impedance device 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 the active antennas AA1 to AA9 can be adjusted. This allows beamforming to be performed by generating any phase difference between each of the active antennas AA1 to AA9.

[0038] In order to individually control each antenna in a terahertz wave active array antenna, multiple wiring lines are required, including bias lines for energizing the compound semiconductor, synchronization lines for controlling synchronization between antennas, and control lines for injecting baseband signals into the antennas. While increasing the number of antennas is necessary to improve antenna gain, increasing the number of antennas increases wiring inductance due to layout, potentially hindering higher frequencies. In contrast, in this embodiment, a compound semiconductor antenna substrate (first substrate 151) including the antenna array and a Si integrated circuit substrate (second substrate) 152 are stacked using semiconductor bonding technology. This eliminates the need to integrate peripheral circuits required for active antenna array control on the compound semiconductor substrate or to implement external connections. This suppresses the increase in inductance due to wiring, typically keeping it below 1 nH, thereby reducing signal loss and signal delay for baseband signals modulated at high frequencies of 1 GHz or higher.

[0039] Furthermore, since there are no circuits around the antenna unrelated to the transmission and reception of terahertz waves, or the number of such circuits can be sufficiently reduced, noise due to unnecessary reflections is reduced, allowing the antenna characteristics to 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 including the antenna array can be directly connected to the integrated circuit on 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, which serves as a reflector). This allows the number of active antennas included in the antenna array to be increased without being affected by the layout. Furthermore, the second substrate 152 including the integrated circuit can be configured with complex circuits such as detection circuits and signal processing circuits using conventional CMOS integrated circuit technology. Therefore, using a configuration such as that of this embodiment enables more sophisticated and cost-effective antenna devices and makes it easier to utilize electromagnetic waves in the terahertz band.

[0040] [Embodiment 2] FIG. 3A shows a plan view of the antenna array 21 according to the second embodiment, and FIGS. 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) is used as the insulator layer 131 of the first substrate 151 on which compound semiconductors are integrated. Hereinafter, in this embodiment, the insulator layer 131 is described as a semiconductor layer. To reduce wiring inductance, the thickness of the semiconductor substrate 10 is preferably 100 μm or less, and more preferably 10 μm or less. The thickness is designed to be 1 / 10 or less of the wavelength of the terahertz wave to be used. In one example, the thickness is 1 / 20 or less of the wavelength of the terahertz wave to be used.

[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 a second substrate 152 including an integrated circuit is bonded to the bonding surface BS. In this embodiment, Cu-Cu bonding and SiO X / SiO X It is assumed that tiling is performed by joining the cut-out first substrate 151 to a 12-inch Si integrated circuit substrate using hybrid joining.

[0042] The first substrate 151 is formed by laminating an insulator layer 148, a semiconductor substrate 131, a conductor layer 109, and insulator layers 105, 104, and 112 in this order from a bonding surface BS with the second substrate 152. Vias 103, 107, and 117, and conductor layers 101, 102, and 111 are formed in the insulator layers 105 and 104, respectively. The bonding surface BS side of the first substrate 151 with the second substrate 152 is disposed opposite the semiconductor layer 100, with the conductor layer 109, which serves as a reflector, interposed therebetween. A through via 137 is formed in the semiconductor substrate 131 so as to penetrate the semiconductor substrate 131. Copper (Cu) or gold (Au) is preferably used as the material for the through via 137. The bonding insulator layer 148 and electrode layer 138 are planarized at the bonding surface BS, and the bonding process is performed with the flat bonding surface BS exposed. On the second substrate 152 side, a semiconductor substrate 134 as a base material and an insulator layer 132 are laminated in this order, and within the insulator layer 132, a conductor layer 140 constituting multilayer wiring, a via 141, and an electrode layer 139 for bonding are formed. 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. The insulator layers 132 and 148 are made of silicon oxide (SiO X ), silicon nitride (SiN XInorganic insulating materials such as silicon oxynitride (SiON), silicon dioxide containing carbon (SiOC), and silicon carbide (SiC) are used. As described above, the plate thickness is designed to be within the range of 1 / 10 or less of the wavelength of the terahertz wave to be used. Therefore, the distance between the conductor layer 111 and the semiconductor substrate 134 can also be set to 1 / 10 or less 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] 3B(1) is an AA' cross section of the antenna array 21. The active antennas AA1 to AA on the first substrate 151 n Conductor layer 109, which serves as a reflector in the semiconductor substrate 131, is electrically connected to bonding surface BS in the order of through via 137g provided in semiconductor substrate 131 and bonding electrode layer 138g formed in insulator layer 148. Conductor layer 140, which is the GND of second substrate 152, is connected to via 141g formed in integrated circuit region 154 and bonding electrode layer 139g in that order, and reaches bonding surface BS. Electrode layer 138g of first substrate 151 and electrode layer 139g of second substrate 152 are electrically connected at bonding surface BS, so that both substrates share the GND potential.

[0044] 3B(2) is a B-B' cross section of the antenna array 21. The 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 this order to the via 117 formed in the dielectric layer 105, the wiring layer 135b provided in the opening 136b, the through via 137b provided in the semiconductor substrate 131, and the 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 is connected in this order to the via 141b formed in the integrated circuit region 154 and the junction electrode layer 139b, and reaches the junction surface BS.

[0045] Each antenna is individually electrically connected 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. This allows the bias wiring layer 102 for the antenna array and the transistor TRa in the integrated circuit region 154 to be electrically connected, enabling individual control signals to be applied to each antenna. The MOS-FET of the transistor TRb in the bias control wiring layer 102 also functions as a bias control unit and operates as a switching regulator, individually controlling the bias signal to the semiconductor layer 100. Alternatively, a terminal for applying a bias signal may be provided separately on the second substrate 152, and the transistor TRa may be operated as an analog switch that turns the antennas on and off individually, thereby supplying voltage from outside the second substrate 152. With this configuration, the bias of each active antenna can be individually changed to create a phase difference between adjacent antennas, thereby achieving beamforming.

[0046] [Embodiment 3] FIG. 4A is a plan view of an antenna array 31 according to a third embodiment, and FIGS. 4B(1) to 4B(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 a second substrate 152 including an integrated circuit is electrically connected to active antennas AA1 to AA9 individually. The active antenna AA1 is composed 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 within the antenna AA (i.e., a position where the electric field of the standing wave of the terahertz wave becomes zero). In this configuration, the two RTDs oscillate in a push-pull mode where they are mutually injection locked with their phases reversed (anti-phase). As shown in Figure 4A, a configuration in which the RTDs are arranged symmetrically in the left and right directions and up and down within the antenna is a configuration that makes it easier to obtain an improvement in directivity as the number of arrays increases.

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

[0048] A bias wiring layer 102 common to all active antennas AA1 to AA9 is provided to apply a bias control signal to the semiconductor layer 100. The wiring layer 102 is connected to the active antennas AA1 to AA9 via vias 107a and 107b arranged for each antenna, and a frequency f THz The wiring layer 102 is connected to the MIM capacitors 126 and the resistive layers 127 arranged for each antenna, and is positioned so as to be connected to the active antennas AA1 to AA9 at the node positions of the resonant electric field formed on the active antennas AA1 to AA9 at a frequency f THz By AC shorting out the high frequencies other than the above, the impedance at high frequencies is reduced, which suppresses multimode oscillation in the array antenna.

[0049] 3B(3) is a CC' cross section of the antenna array 31. The 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 bonding surface BS in the following order: a via 117 formed in the dielectric layer 105, a wiring layer 135b provided in the opening 136b of the conductor layer 109, a through via 137b provided in the semiconductor substrate 131, and a bonding 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 is connected to the via 141b and the bonding electrode layer 139b formed in the integrated circuit region 154 in this order, and reaches the bonding surface BS. 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 electrically connected, making it possible to apply bias control signals to all antennas. The bias control wiring layer 143 receives a bias signal, which is separately provided on the second substrate 152, as a voltage supplied from the outside via an application terminal.

[0050] The active antennas AA1 to AA9 are provided with vias 130 for coupling injection-locked signals from the master oscillator 60. The vias 130 are capacitively coupled to the conductor layer 101 of the active antenna through a capacitance C, and the master oscillator 60 and the active antennas AA are electrically connected to each other so as to be shorted in the terahertz band and open in the RF band. The vias 130 are also used to couple the injection-locked signals of the frequency f THz The connection position is set so that the via 130 is connected at the node position of the resonant electric field of frequency f THz The impedance is high at the terahertz frequency and low at the subharmonic frequency, realizing both terahertz radiation efficiency and master signal injection efficiency.

[0051] The master oscillator 60 generates a subharmonic frequency (f THz / 2) and controls the phase of each active antenna. The master oscillator 60 outputs a signal larger than the output of each slave active antenna. The active antenna AA is electrically connected to the gate of a transistor TRa (MOS-FET) of the master oscillator 60 provided in an integrated circuit region 154 of the second substrate 152 through a master oscillation via 130. 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 following order: a wiring layer 135a provided in an opening 136a of the conductor layer 109; a through via 137a provided in the insulator layer 131; and a 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 following order: a via 141a formed in the integrated circuit region 154; and a 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 bonding surface BS. As a result, the transistors TRa for individually controlling each antenna, which are arranged in the active antenna arrays AA1 to AA9 and the integrated circuit region 154, become conductive in the terahertz band and are ready to apply control signals. Each active antenna has a bias structure that applies a potential difference between the top and bottom of the semiconductor structure 162, consisting of the upper electrode layer 163 and the via 103, and the lower electrode layer 164 and the conductor layer 109. A 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 THz By injecting a power signal of f / 2, the phase of each active antenna can be controlled. A device with this configuration can generate subharmonic waves (f THz / n, where n is a natural number) is used as the master oscillator, which is a subharmonic oscillator circuit that outputs a frequency f THz This injection locks the active antenna array operating at frequency f THzThis allows for control of the timing in the phase noise, thereby reducing the phase noise.

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

[0054] The receiving antenna 503 is a patch antenna having a structure in which the negative resistance element 300 and the dielectric 312 are sandwiched between a conductor layer 507, which is an upper conductor for the receiving antenna, and a conductor layer 309, which is a reflector. The upper terminal of the negative resistance element 300 is electrically connected to the via 301, which is electrically connected to the conductor layer 507. The lower terminal of the negative resistance element 300 is electrically connected to the conductor layer 309, which is also a GND. The conductor layer 507 is THz The negative resistance element 300 is configured to be connected to the individual bias conductor layer 303 via a power feed via 307 that 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 an MIM capacitor connection 321. The MIM capacitor connection 321 includes a resistive layer made of TiW and acts as an AC short connected in series with the MIM capacitor structure. When a signal with a predetermined bias voltage that generates negative resistance is applied to the negative resistance element, self-oscillation occurs, and the connection 321 prevents output reduction and oscillation instability due to parasitic oscillation. The transmitting antenna 504 has a configuration similar to the receiving antenna, except for the 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] 5A shows the cross-sectional structure of each active antenna 503, 504. A bonding surface BS is provided on the back surface of the first substrate 151, and the outermost surface of the bonding surface BS side of the semiconductor substrate 302, which is the base material of the first substrate 151, is bonded to the outermost surface of the bonding surface BS side of the second substrate 152 on which an integrated circuit is formed. An integrated circuit region 154 is formed on the second substrate 152, and the integrated circuit region 154 includes a semiconductor substrate 1901, which is the base material, and a control circuit 165 formed on an insulator layer 1902 of the integrated circuit. The bonding surface BS is a bonding interface formed by directly bonding a conductor layer 1910 formed on the back surface of the semiconductor substrate 302, which is the first substrate, to the metal of the conductor layer 1911 exposed on the outermost surface of the second substrate 152. Here, bonding forms include metal bonding such as Cu-Cu bonding, SiO X / SiO X Insulator bonding such as bonding, adhesive bonding using an adhesive such as BCB, and hybrid bonding, which is a combination of these, can be used. Furthermore, bonding processes such as low-temperature bonding using plasma activation and conventional thermocompression bonding can be used. Also, bonding of semiconductor wafers of the same size, bonding of semiconductor wafers of different sizes, and a method of bonding multiple semiconductor chips spaced apart on a wafer (tiling) can be used. Although the drive circuit integrated on the second substrate 152 is described as an example of this embodiment, the connection and structure are not limited to this.

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

[0057] In FIG. 5B(2), an MIM capacitor 320 is provided in the bias path of the first substrate 151. The MIM capacitor 320 has a capacitance structure formed by a conductor layer 325 connected to the tip of an MIM capacitor connection portion 321 extending from a conductor layer 303 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 serving as a GND. However, this is not limiting and any MIS (Metal-Insulator-Semiconductor) structure may be used as long as it forms capacitance. Furthermore, the conductor layer 1908 serving as a GND of the second substrate 152 may be common to the GND layer and GND potential of the integrated circuit region 154 of the second substrate 152, or multiple conductor layers 1908 and 1912 serving as GND may be provided. Furthermore, the conductor layers 309 and 140 serving as GND may be solid patterns. For example, to increase bonding strength, dummy electrode layers 1909 and 1912 not connected to signal lines may be provided on the bonding surface BS. By distributing dummy electrode layers 1909 and 1912 in a wide solid pattern in areas where wiring electrodes are not required, the bonding strength can be increased, contributing to improved yield and reliability. In addition, such a solid GND configuration can reduce the influence of electromagnetic noise caused by the integrated circuit on the second substrate on the terahertz antenna on first substrate 151.

[0058] The bias control will now be described. The through via 305 connected to the conductor layer 303, the wiring layer 135b provided in the opening 136b of the conductor layer 309 serving as a reflector, and the through via 137b formed in the semiconductor substrate 302 are electrically connected in this order to a conductor layer (electrode layer) 1910 that forms an electrode serving as a bias terminal formed on the junction surface BS. Similarly, on the second substrate 1903 side, a conductor layer 1911 serving as a bias terminal formed on the junction surface BS is electrically connected to a MOS-FET 322 that is a transistor formed in the integrated circuit region 154. The MOS-FET 322 constitutes a grounded-gate amplifier circuit as a first-stage amplifier. The amplified signal is further amplified by a grounded-source amplifier circuit including a MOS-FET 324. The grounded-gate amplifier circuit and the grounded-source amplifier circuit are coupled by an MIM capacitor 323 for AC coupling. The MIM capacitor 323 is an example, and a configuration using a gate insulating film capacitance of a FET may also be used. The MOS-FET 1322 also serves as a bias control section, and is connected to the semiconductor substrate through the MOS-FET 322 to apply a bias voltage to the negative differential resistance element 300. Alternatively, a terminal for applying the bias voltage may be provided on the second substrate 152, and a voltage may be supplied from outside.

[0059] In this embodiment, by bonding the first substrate 151, which has the transmitting and receiving active antennas, and the second substrate 152, which has the electronic integrated circuit, using semiconductor bonding technology, it is not necessary to integrate and mount the control circuit for the active antenna on the same plane. This reduces the space required for arranging the control circuit on the same plane as the antenna, preventing degradation of antenna characteristics due to coupling between the control circuit and the antenna. Individual control of bias and other parameters for each antenna requires individual bias terminals. However, in this embodiment, through-vias 305 allow easy connection to the integrated circuit region 154. By wiring the control circuit on the backside of the first substrate 151, the number of antenna arrays can be increased without being affected by layout constraints, even when using an active antenna array as in the previous embodiment. The electronic integrated circuit on the second substrate 152, which serves as the control circuit, is fabricated using conventional CMOS technology, allowing for complex circuits to be configured for the detection circuit and signal processing circuit. This further expands the applications of the terahertz wave receiving device using the active antenna of this embodiment.

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

[0061] Terahertz waves emitted from transmitting unit 1101 are reflected by subject 1105 and detected by receiving unit 1102. A camera system having such transmitting unit 1101 and receiving unit 1102 may also be called an active camera system. Note that in a passive camera system without transmitting unit 1101, the antenna device of each of the above-described embodiments can be used as receiving unit 1102.

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

[0063] [Embodiment 6] In this embodiment, a case will be described in which the antenna device according to any of the above-described embodiments is applied to a terahertz communication system (communication device). The following description will be given with reference to FIG. 6(b). The antenna device can be used as an antenna 1200 in the communication system. Possible communication systems include a simple ASK system, a superheterodyne system, a direct conversion system, and the like. A superheterodyne communication system includes, for example, 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 receiver, a terahertz wave received via the antenna 1200 is converted into an intermediate frequency signal by the mixer 1202, and then converted into a baseband signal by the mixer 1204. The analog waveform is converted into a digital waveform by the converter 1205. The digital waveform is then demodulated at baseband to obtain a communication signal. In the transmitter, a communication signal is modulated and then converted from a digital waveform to an analog waveform by converter 1205. It is then frequency-converted via mixer 1204 and mixer 1202 and output as a terahertz wave from antenna 1200. A direct-conversion communication system includes antenna 1200, amplifier 1211, mixer 1212, modulator / demodulator 1213, and local oscillator 1214. In the direct-conversion system, during reception, mixer 1212 directly converts the received terahertz wave into a baseband signal. During transmission, mixer 1212 converts the baseband signal to be transmitted into a terahertz signal. The other configurations are the same as those of the superheterodyne system. The antenna devices according to the above-described embodiments can perform terahertz wave beamforming by electrical control of the chip alone. This allows for alignment of radio waves between transmitters and receivers. Therefore, by using the antenna device of each embodiment capable of beamforming, it is possible to improve wireless quality such as signal-to-noise ratio in a communication system, and transmit large amounts of information over a wide coverage area at low cost.

[0064] [Other embodiments] Although the 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 the gist of the present invention.

[0065] For example, in the above-described embodiment, the carriers are assumed to be electrons, but the present invention is not limited to this and may be implemented using holes. Furthermore, the materials for the substrate and dielectric may be selected according to the intended use, and semiconductor layers such as silicon, gallium arsenide, indium arsenide, and gallium phosphide, and resins such as glass, ceramic, polytetrafluoroethylene, and polyethylene terephthalate may be used.

[0066] Furthermore, although the above-described embodiment uses a square patch antenna as a terahertz wave resonator, the shape of the resonator is not limited to this. For example, a resonator having a structure using a patch conductor of a polygonal shape such as a rectangle or a triangle, a circle, an ellipse, or the like may be used.

[0067] Furthermore, the number of negative differential resistance elements integrated in the element is not limited to one, and a resonator including multiple negative differential resistance elements may be used. The number of lines is also not limited to one, and a configuration having multiple lines may be used. By using the antenna device described in the above-mentioned embodiments, it is possible to oscillate and detect terahertz waves.

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

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

[0070] The semiconductor layer 100 may also be a quantum cascade laser (QCL) structure having a multilayer structure of several hundred to several thousand semiconductor layers. In this case, the semiconductor layer 100 is a semiconductor layer including a QCL structure. The semiconductor layer 100 may also be a negative resistance element such as a Gunn diode or an IMPATT diode, which are often used in the millimeter wave band. The semiconductor layer 100 may also be a high-frequency element such as a transistor terminated at one terminal. Suitable transistors include a heterojunction bipolar transistor (HBT), a compound semiconductor layer-based FET, and a high electron mobility transistor (HEMT). The semiconductor layer 100 may also be a Josephson device using a superconductor layer, which has a negative differential resistance.

[0071] The relationship between the active antenna array 11 and the control circuit 165 may be any form. The active antenna array 11 includes a plurality of active antennas AA 11 ~AA mn The control circuit 165 includes a plurality of control elements AC 11 ~AC mn Includes. Multiple active antennas AA 11 ~AA mn Each of them has multiple control elements AC 11 ~AC mnIn other words, one control element may control one active antenna. This increases the degree of freedom in controlling the antenna. Note that the control circuit 165 may control a plurality of control elements AC 11 ~AC mn However, the present invention is not limited to the above, and it is sufficient if the active antennas can be individually controlled.

[0072] Alternatively, one control element may control multiple active antennas included in one group. In this case, the multiple active antennas included in one group may be multiple active antennas AA arranged in a matrix. 11 ~AA mn The active antennas in one group may be arranged in rows or columns. The active antennas in one group may be arranged in multiple rows or columns. Operating each active antenna individually makes control easier. Furthermore, the output of each active antenna can be increased.

[0073] Furthermore, multiple control elements may control one active antenna, which increases the degree of freedom of operation, such as controlling one active antenna at a time or controlling multiple active antennas.

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

[0075] [Summary of the embodiment] At least some of the above-described embodiments can be summarized as follows.

[0076] (Item 1) An antenna device, a first substrate including an antenna array provided with a plurality of active antennas, each of which includes a semiconductor structure and an antenna that generate or detect electromagnetic waves, 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 bonded together 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:

[0077] (Item 2) 2. The antenna device according to item 1, wherein 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, each of which is connected to each of the plurality of active antennas in a one-to-one relationship.

[0079] (Item 4) 4. The antenna device according to any one of items 1 to 3, wherein 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 described in any one of items 1 to 4, characterized in that the multiple active antennas include a first conductor formed on a first layer of the first substrate and a second conductor formed on a second layer arranged between the first layer and the bonding surface and having a larger area than the first conductor.

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

[0082] (Item 7) 7. The antenna device according to item 5 or 6, 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.

[0083] (Item 8) 8. The antenna device according to item 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.

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

[0085] (Item 10) 10. The antenna device according to item 8 or 9, wherein the second via is arranged at a position where it does not overlap with the first conductor in the stacking direction of the first substrate.

[0086] (Item 11) The antenna device according to any one of items 5 to 10, further comprising a coupling line that electrically couples adjacent active antennas, the length of the coupling line being set based on the electrical length of the electromagnetic wave in the coupling line.

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

[0088] (Item 13) Item 13. The antenna device according to item 12, wherein the length of the third via is 1 / 10 or less 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; 14. The antenna device according to any one of items 11 to 13, wherein the coupling wire is connected to a wiring provided on the third layer by a fourth via.

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

[0091] (Item 16) Item 15. The antenna device according to item 14, wherein the fourth via is arranged at a node position of the standing wave of the electromagnetic wave in the coupled line.

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

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

[0094] (Item 19) Item 19. The antenna device according to item 18, wherein the third conductor is a solid pattern.

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

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

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

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

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

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

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

[0102] (Item 27) 12. The antenna device according to item 11, wherein the control circuit is a phase control circuit for controlling the phase of the electromagnetic wave output to the antenna array.

[0103] (Item 28) 28. The antenna device according to item 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.

[0104] (Item 29) 28. The antenna device according to item 27, wherein the phase control circuit has an impedance variable device that adjusts the impedance of the coupling line at the frequency of the electromagnetic wave.

[0105] (Item 30) 30. The antenna device according to any one of items 1 to 29, 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.

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

[0107] (Item 32) 32. The antenna device according to any one of items 1 to 31, wherein the electromagnetic waves are electromagnetic waves in the terahertz band.

[0108] (Item 33) The antenna device according to any one of items 1 to 32, a transmitter that emits the electromagnetic wave; a receiving unit that detects the electromagnetic waves; A communication device comprising:

[0109] (Item 34) The antenna device according to any one of items 1 to 32, a transmitter that emits the electromagnetic waves toward a subject; a detection unit that detects the electromagnetic waves reflected by the subject; An imaging system comprising: [Explanation of symbols]

[0110] AA active antenna, 100 semiconductor (RTD), CL transmission line (coupled line), VZ impedance variable device, 101 upper conductor layer of patch antenna, 102 wiring layer for bias, 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 capacitor, 127 resistive layer (TiW), 128 conductor layer (D), 130 via (master synchronization line), 131 insulator layer, 132 insulator layer, 133 Insulator layer, 134 second semiconductor substrate, 135 wiring layer (reflector opening), 136 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 supply), 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 capacitor (second), 162 upper electrode layer, 163 semiconductor structure layer, 164 lower electrode layer

Claims

1. An antenna device, a first substrate including an antenna array provided with a plurality of active antennas, each of which includes a semiconductor structure and an antenna that generate or detect electromagnetic waves, 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 bonded together 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; 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. 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. An antenna device as 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 joint 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 lengths of the first and second vias are 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 where it does not overlap with the first conductor in the stacking direction of the first substrate.

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

12. 12. The antenna device according to claim 11, further comprising a third via provided through an opening in the second layer, the third via electrically connecting the coupled wire 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. 15. The antenna device according to claim 14, wherein the fourth via is arranged at a position different from a node of the standing wave of the electromagnetic wave on 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 provided between the joint surface and the control circuit, the fourth layer including a third conductor having an area larger than that of the first conductor.

19. 19. 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 supplying 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 the 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 variable device that adjusts the impedance of the coupled wire 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 transmission and a second active antenna for reception.

32. 2. The antenna device according to claim 1, wherein the electromagnetic waves are in the terahertz band.

33. an antenna device according to any one of claims 1 to 32; a transmitter that emits the electromagnetic wave; a receiving unit that detects the electromagnetic waves; A communication device comprising:

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

Images