JP2020150104A - Microwave integrated circuit - Google Patents

Abstract

To provide a microwave integrated circuit which effectively reduces an oscillation in an output signal.SOLUTION: A microwave integrated circuit includes: a semiconductor substrate 3; a plurality of amplification units formed in the semiconductor substrate 3; an electric wiring W3 that is formed in one electric wiring layer excluding the electric wiring layer of a top layer and the electric wiring layer of a bottom layer from a plurality of electric wiring layers formed on the semiconductor substrate 3, and supplies a power source to a plurality of amplification units; a plurality of conductive regions 51 formed while nipping the electric wiring W3 in the electric wiring layer; a plurality of vias 21a that connect an another conductive region 53 formed in a region that nips the electric wiring W3 in the two electric wiring layers just above and just under the electric wiring layer with a WG. Each of the plurality of vias 21a forms a via structure connected by a plurality of other vias 21b and 21d in conductive regions 55 and 59 of the electric wiring layer of the bottom layer.SELECTED DRAWING: Figure 6

Description

The present invention relates to microwave integrated circuits.

Conventionally, microwave integrated circuits that integrate microwave devices have been used. As a microwave integrated circuit, a multilayer MMIC (Monolithic Microwave Integrated Circuit) in which an insulating layer and a wiring layer are laminated on a semiconductor substrate on which a circuit element such as a transistor is formed is known (for example, the following patent documents). See 1-3). According to such a multi-layered MMIC structure, it is possible to reduce the occupied area of the circuit.

Japanese Unexamined Patent Publication No. 2003-309121 Japanese Unexamined Patent Publication No. 2010-205941 Japanese Unexamined Patent Publication No. 2017-085040

In recent years, in the microwave integrated circuit having the structure of the conventional multilayer MMIC described above, there is a demand for miniaturization of the circuit size. However, in a conventional microwave integrated circuit in which the circuit size is reduced, the isolation between each circuit unit is insufficient, and oscillation may occur in the output signal.

Therefore, the present invention has been made in view of such a problem, and an object of the present invention is to provide a microwave integrated circuit capable of effectively reducing oscillation in an output signal.

In order to solve the above problems, the microwave integrated circuit according to one aspect of the present invention comprises a semiconductor substrate, a plurality of amplification units formed in the semiconductor substrate, and a plurality of wiring layers formed on the semiconductor substrate. Of these, a power supply line formed in one wiring layer excluding the uppermost wiring layer and the lowermost wiring layer to supply power to a plurality of amplification units, and the power supply line sandwiched between the power supply lines in one wiring layer. It has a plurality of vias connecting a plurality of conductive regions and another conductive region formed in a region sandwiching the power supply line in two wiring layers directly above and below one wiring layer, and a plurality of vias. Each of the vias forms a via structure connected by a plurality of different vias to at least one of the uppermost wiring layer and the lowest wiring layer.

According to the present invention, oscillation in the output signal can be effectively reduced.

It is a top view of the microwave integrated circuit 1 which concerns on embodiment. It is sectional drawing of the microwave integrated circuit of FIG. It is a block diagram which shows the whole circuit structure of the microwave integrated circuit 1 of FIG. It is a figure which shows the arrangement of each circuit unit seen from the surface side in the microwave integrated circuit 1 of FIG. 1, the bias given to each circuit unit, and the path of the RF signal input / output between each circuit unit. It is a circuit diagram which shows the circuit structure of each amplification unit configured in the microwave integrated circuit 1 of FIG. It is sectional drawing in the direction perpendicular to the formation direction of the wiring W1 in the vicinity of wirings W1 and W3 in the microwave integrated circuit 1 of FIG. It is a top view of the via structure formed in the multilayer wiring layer 5. It is a top view which shows the state of the arrangement of the via structure of FIG. It is a graph which shows the effect of preventing the oscillation of an output signal by a microwave integrated circuit 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.
[Microwave integrated circuit configuration]

FIG. 1 is a plan view of the microwave integrated circuit 1 according to the embodiment, and FIG. 2 is a cross-sectional view of the microwave integrated circuit. The microwave integrated circuit 1 shown in FIGS. 1 and 2 is an integrated circuit that amplifies and outputs a microwave signal, and is a WLCSP (Wafer Level Chip Size Package) chip that is a MMIC that can be flip-chip mounted face-down. is there. The microwave integrated circuit 1 includes a semiconductor substrate 3 which is a GaAs substrate in which a circuit unit including a FET (Field Effect Transistor) is formed, a multilayer wiring layer 5 laminated on the semiconductor substrate 3, and a multilayer wiring layer. 5 includes a solder ball 9 formed on the surface 7 opposite to the semiconductor substrate 3. The semiconductor substrate 3 and the multilayer wiring layer 5 have a rectangular planar shape having a size of, for example, 2.3 mm × 1.66 mm in a plan view.

On the surface of the semiconductor substrate 3 on the multilayer wiring layer 5 side, a conductive film 15 that functions as a terminal of each circuit element such as the FET 11 and the resistance element 13 formed inside the semiconductor substrate 3 is formed, and the back surface of the semiconductor substrate 3 is formed. A protective film 16 is formed on the semiconductor substrate 16, and the multilayer wiring layer 5 is laminated on the surface of the semiconductor substrate 3 on which the conductive film 15 is formed. The multilayer wiring layer 5 has a five-layer structure of a first insulating layer 17a, a second insulating layer 17b, a third insulating layer 17c, a fourth insulating layer 17d, and a fifth insulating layer 17e, and has a first insulating layer 17a. The first layer wiring 19a is formed on the surface of the second insulating layer 17b on the side of the second insulating layer 17b, the second layer wiring 19b is formed on the surface of the second insulating layer 17b on the side of the third insulating layer 17c, and the third insulating layer 17c is formed. The third layer wiring 19c is formed on the surface of the fourth insulating layer 17d on the side of the fifth insulating layer 17d, and the fourth layer wiring 19d is formed on the surface of the fourth insulating layer 17d on the side of the fifth insulating layer 17e.

The first insulating layer 17a is formed from the polyimide film and the SiN film on the surface of the semiconductor substrate 3 in which the conductive film 15 corresponding to each electrode of the FET 11 and the conductive film 15 between them are covered with a SiN film (SiN passivation film). It is formed of two layers. For example, the first insulating layer 17a is formed with a polyimide film having a thickness of 1.4 μm and a SiN film having a thickness of 0.1 μm. The surface of the first insulating layer 17a is plated with gold on the metal seed layer to form the first layer wiring 19a. For example, the first layer wiring 19a is formed with a metal seed layer having a thickness of 0.515 μm and a gold plating having a thickness of 1 μm.

The second to fourth insulating layers 17b to 17d are formed of two layers composed of a SiN film and a polyimide film on the first to third insulating layers 17a to 17c, respectively. For example, the second insulating layer 17b is formed with two layers having thicknesses of 0.33 μm and 2.0 μm, and the third insulating layer 17b is formed with two layers having thicknesses of 0.3 μm and 2.0 μm. The fourth insulating layer 17c is formed with two layers having a thickness of 0.2 μm and 2.0 μm. The surfaces of the second to fourth insulating layers 17b to 17d are gold-plated on the metal seed layer to form the second to fourth layer wirings 19b to 19d. For example, the second layer wiring 19b and the third layer wiring 19c are formed with a metal seed layer thickness of 0.205 μm and a gold plating thickness of 1 μm, and the fourth layer wiring 19d is formed with a metal seed layer thickness. Is 0.205 μm, and the thickness of the gold plating is 2 μm.

The fifth insulating layer 17e is formed on the fourth insulating layer 17d by two layers composed of a SiN film and a polyimide film. For example, the fifth insulating layer 17e is formed with two layers having a thickness of 0.2 μm and 2.5 μm. On the surface of the fifth insulating layer 17e, a plurality of solder balls 9 which are spherical conductors electrically connected to the circuit unit inside the semiconductor substrate 3 or the first to fourth layer wirings 19d are two-dimensional. Are arranged and formed. These solder balls 9 are electrically connected to the wiring on the mounting board when the microwave integrated circuit 1 is flip-chip mounted on the mounting board.

In the multilayer wiring layer 5 having the above configuration, the solder balls 9, the conductive film 15, and the first to fourth layer wirings 19a to 19d penetrate one or more of the first to fifth insulating layers 17a to 17e. The vias 21 are electrically connected to each other. Further, in the multilayer wiring layer 5, for example, in the second insulating layer 17b, a passive element such as a capacitor 23 is connected to the wiring of any two layers such as the first layer wiring 19a and the second layer wiring 19b. It is formed in a state of being.

FIG. 3 is a block diagram showing the entire circuit configuration in the microwave integrated circuit 1. As shown in FIG. 3, the microwave integrated circuit 1, a first frequency input from an input terminal (signal input terminal) P _IN (e.g., frequency 38 GHz) in the first-stage amplifier for amplifying an RF signal (radio frequency signal) of A low-frequency amplifier (LNA) 31, a main-series amplifier stage that amplifies the RF signal of one of the first frequencies branched into two after being amplified by the low-frequency amplifier 31, and a low-noise amplifier 31. A branch stage that multiplies the RF signal of the other first frequency, which is amplified and then branched into two, to generate a multiplied wave (for example, an RF signal having a frequency of 77 GHz) that is twice the frequency of the first frequency. A sub-series amplification stage that amplifies and outputs the multiplication wave output from the branch stage is integrated on the semiconductor substrate 3.

The main series amplifier stage has a configuration of a two-stage amplifier circuit in which a driver amplifier (Driver Amplifier) 33 and a power amplifier (Power Amplifier) 35 are connected in series, and an output terminal (signal output terminal) P. The RF signal of the first frequency amplified to a predetermined signal strength (for example, 50 mW) is output from _OUT1 . The branch stage has a configuration in which a multiplier 39 is sandwiched between a low noise amplifier 37 and a low noise amplifier 41, which are two-stage amplifier circuits, and amplifies and outputs an RF signal of a second frequency. The sub-series amplifier stage has a configuration of a two-stage amplifier circuit in which a driver amplifier 43 and a power amplifier 45 are connected in series, and is connected to the subsequent stage of the branch stage. In this branching stage, the RF signal branched from the low noise amplifier 31 is amplified by the low noise amplifier 37, and the frequency of the RF signal is multiplied by the multiplier 39 to multiply the frequency of the second frequency (for example, frequency 77 GHz). After the RF signal) is generated, the multiplied wave is amplified again by the low noise amplifier 41. Further, the multiplication wave generated by the branch stage is sequentially amplified by the driver amplifier 43 and the power amplifier 45 of the sub-series amplification stage, and is output from the output terminal P _{OUT 2} as a multiplication wave having a predetermined signal strength (for example, 30 mW).

Among the above circuit configurations, the low noise amplifier 31, the low noise amplifiers 37 and 41 included in the branch stage, the driver amplifier 33 and the power amplifier 35 included in the main series amplification stage, and the driver amplifier 43 and power included in the sub series amplification stage. Each amplification unit including the amplifier 45 adopts the configuration of a current reuse type amplifier including a two-stage FET, as will be described later. On the other hand, the multiplier 39 is composed of a one-stage FET (field effect transistor) which is a non-linear element, and by setting the bias deeply or shallowly, the output including harmonic components from the drain due to the non-linearity of the input / output characteristics. Harmonics can be easily generated by performing a non-linear operation that outputs a signal. Then, the multiplier 39 outputs only a predetermined multiplied wave (for example, a double wave) from the drain output by providing a limitation of the band (cutoff frequency).

FIG. 4 shows the arrangement of each circuit unit seen from the surface side in the microwave integrated circuit 1, the bias given to each circuit unit, and the path of the RF signal input / output between each circuit unit. Here, the bias path is shown by a solid line, the RF signal (including the multiplication wave) path is shown by a dotted line, the bias path is formed by the third layer wiring 19c, and the RF signal path is the first layer wiring 19a and. It is formed by the second layer wiring 19b.

One side 5a side of the multilayer wiring layer 5 of a microwave integrated circuit 1, the solder balls 9a is provided with a function of the input terminal P _IN, in order to prevent oscillation of the output due to the coupling between the input and output, the sub-sequence amplification stage The solder ball 9b having the role of the output terminal P _OUT2 of the above is provided on the side 5b on the opposite side of the side 5a of the multilayer wiring layer 5. Further, the solder ball 9c having the role of the output terminal P _{OUT 1} of the main sequence amplification stage is provided with the multilayer wiring layer 5 in order to prevent the output from oscillating due to the coupling between the input and output and the coupling with the sub series amplification stage. It is provided on the side 5c adjacent to the sides 5a and 5b.

Corresponding to the arrangement of the solder balls 9a, 9b, 9c described above, the arrangement of each circuit unit is set as follows. The low noise amplifier 31 is arranged near the center of one side 5a corresponding to the position of the solder ball 9a, and constitutes a branch stage and a sub-series amplification stage, a multiplier 39, a low noise amplifier 41, a driver amplifier 43, and a power amplifier. The 45 is arranged side by side between the side 5a and the side 5b and closer to the side 5d on the opposite side of the side 5c. On the other hand, with respect to the driver amplifier 33 and the power amplifier 35 constituting the main sequence amplification stage, the driver amplifier 33 is arranged closer to one side 5b from the center of the surface in order to secure an arrangement space, and the power amplifier 35 is placed on the solder ball 9c. It is arranged on the closest side 5c side. Corresponding to the above arrangement, wiring for RF signal transmission along one side 5c as an RF signal path between the output of the driver amplifier 33 and the input of the power amplifier 35 in the first layer wiring 19a. W1 is provided.

Further, a path (power supply line) and a solder ball 9 for supplying a bias (power supply) to each circuit unit are also formed in the multilayer wiring layer 5 of the microwave integrated circuit 1. That is, a solder ball for supplying a common bias (first power supply voltage) VDD1 that drives the low noise amplifier 31 and the driver amplifier 33 of the first stage of the main series amplification stage to one side 5a side of the surface of the multilayer wiring layer 5. 9d and a solder ball 9e for supplying a bias (fourth power supply voltage) VDD4 for driving the power amplifier 35 at the final stage of the main series amplification stage are provided. Wiring W2 for electrically connecting the solder ball 9e and the power amplifier 35 is formed in the third layer wiring 19c, and wiring W3 for electrically connecting the solder ball 9d and the low noise amplifier 31 and the driver amplifier 33 is provided. It is formed. The wiring W3 is formed adjacent to the center side of the surface of the multilayer wiring layer 5 with respect to the RF signal path W1 between the driver amplifier 33 and the power amplifier 35. That is, the wiring W3 is between the position of the position and the output terminal P _OUT1 at which solder balls 9c of the solder balls 9a is an input terminal P _IN, and, between the position of the low-noise amplifier 31 and the position of the wire W1 Is formed in. In addition, a common bias (second power supply voltage) VDD2 for driving the low noise amplifier 37, the multiplier 39, and the low noise amplifier 41 included in the branch stage is supplied to one side 5b side of the surface of the multilayer wiring layer 5. Soldering balls 9f for supplying noise balls 9f and solder balls 9g and 9h for supplying a common bias (third power supply voltage) VDD3 for driving the driver amplifier 43 and the power amplifier 45 in the sub-series amplification stage are provided. Wiring that electrically connects each of these solder balls 9f, 9g, and 9h to each circuit unit is also provided in the third layer wiring 19c.

Next, with reference to FIG. 5, the circuit configuration of each amplification unit including the low noise amplifiers 31, 37, 41, the driver amplifiers 33, 43, and the power amplifiers 35, 45 will be described. Each circuit unit contains a two-stage FET that is connected in series DC between the power supply and ground and connected in series AC between the input of the RF signal and the output of the RF signal. Configure a reuse type amplifier.

That is, each amplification unit is composed of FETs T1 and T2, transmission lines L1 to L4, capacitors C1 to C4, and a resistance element R1. The gate G1 of the FET T1 is AC-connected to the input terminal In via the capacitor C3, and the source S1 is grounded. This input terminal In is a terminal for inputting an RF signal. In addition, the gate G1 of the FET T1 is electrically connected to the power supply terminal VGG for applying the gate bias via the transmission line L1, and the power supply terminal VGG is AC grounded via the capacitor C1. Further, the gate G2 of the FET T2 is electrically connected to the drain D1 of the FET T1 via the transmission lines L2 and L3, and the source S2 thereof is AC grounded via the capacitor C2. Further, the source S2 of the FET T2 is electrically connected to the connection point N1 between the transmission line L2 and the transmission line L3 via the transmission line L4 and the resistance element R1. In addition, the drain D2 of the FET T2 is AC-connected to the output terminal Out for RF signal output via the capacitor C4, and is also connected to the power supply terminal VDD for applying bias. Capacitors C3 and C4 are coupling capacitors for blocking DC components.

In the amplification unit having such a configuration, the bias current flowing from the power supply terminal VDD into the FETT2 flows out from the source S2, passes through the resistance element R1 and the transmission line L4, flows into the drain D1 of the FETT1, and flows from the source S1 of the FETT1. It is discharged to the ground. In this way, by connecting the FETT2 and the FETT2 in series in a direct current manner between the power supply terminal VDD and the ground, it is possible to realize a configuration in which the bias current supplied to the FETT2 is reused in the FETT1 as well.

Further, the resistance element R1 has a role of operating the FET T2 with self-bias. That is, a voltage drop occurs due to the bias current flowing through the resistance element R1, and the voltage drop results in giving the gate bias of the FET T2.

Further, the transmission line L4 has a length of λ / 4 corresponding to the wavelength λ of the RF signal (including the multiplied wave) targeted by the amplification unit. As a result, it is possible to prevent the bias path from affecting the RF signals propagating on the transmission lines L2 and L3. That is, since one end side of the transmission line L4 is AC-grounded by the capacitor C2, the transmission line L4 is substantially AC-opened when viewed from the connection point N1. As a result, the path of the transmission line L4 does not affect the RF signal propagating through the transmission lines L2 and L3.

Further, a gate bias (fixed bias) is directly applied to the gate G1 of the FET T2 from the power supply terminal VGG. Since the transmission line L1 between the power supply terminal VGG and the gate G1 is also set to the length of λ / 4 and one end thereof is AC grounded, the path of the transmission line L1 is from the input terminal In to the gate G1. It also has virtually no effect on the propagating RF signal. In this way, the FET T1 and the FET T2 are connected in series in an alternating current manner between the input terminal In and the output terminal Out, so that the RF signal can be efficiently amplified and output.

The amplification unit having the above configuration has a configuration in which the FET T1 operates with a fixed bias and the FET T2 operates with a self-bias, but the source S1 of the FET T1 is arranged in parallel with the resistor element having the same resistance value as the resistance element R1 and the capacitor. The FET T1 may also be operated by self-bias by grounding the circuit and directly grounding the gate G1 with a resistance element having a significant resistance value or a transmission line having a length of λ / 4. At this time, by setting the two FETs T1 and T2 to the same size (same gate width), the operating conditions of the two FETs are made the same. In the configuration in which one FETT1 is a fixed bias and the other FETT2 is a self-bias as in the circuit configuration of FIG. 5, the fixed bias is adjusted to adjust the operating point of the FETT1 to obtain a two-stage amplifier circuit. The distortion characteristic and the maximum output characteristic can be balanced.

The size (gate width) of the FET included in each amplification unit is set to be the same, for example, as follows.
Low noise amplifier 31 ... 80 μm,
Driver amplifier 33 (38 GHz) ... 240 μm,
Power amplifier 35 (38 GHz) ... 400 μm
Driver amplifier 43 (77GHz) ... 160μm
Power amplifier 45 (77 GHz) ... 300 μm
That is, the size ratio of the FETs included in the two amplifiers 33 and 35 constituting the main series amplification stage is 3: 5, and the size ratio of the FETs included in the two amplifiers 43 and 45 constituting the subseries amplification stage is It is 8:15, and the total size of the FETs contained in the two amplifiers 33 and 35 constituting the main series amplification stage and the total size of the FETs contained in the two amplifiers 43 and 45 constituting the sub-series amplification stage. The ratio with is set to 32:23. This gives the desired output in the specified temperature range.

Next, a via structure for signal shielding formed in the multilayer wiring layer 5 of the microwave integrated circuit 1 will be described with reference to FIGS. 6 to 8. FIG. 6 is a cross-sectional view in a direction perpendicular to the formation direction of the wirings W1 and W3 in the vicinity of the wirings W1 and W3 in the microwave integrated circuit 1, and FIG. 7 is a plan view of the via structure formed in the multilayer wiring layer 5. FIG. 8 is a plan view schematically showing the arrangement of via structures. In FIG. 6, the solder ball 9 is not shown.

As shown in FIG. 6, the third layer wiring 19c on the third insulating layer 17c is provided with the wiring W3 for bias supply, and the first layer wiring 19a on the first insulating layer 17a is RF in parallel with the wiring W3. Wiring W1 for signal transmission is provided, and a ground wiring layer WG connected to the ground via a solder ball 9 is provided on the fourth layer wiring 19d on the fourth insulating layer 17d. A plurality of conductive regions 51 formed in parallel with the wiring W3 from both sides are formed on the third insulating layer 17c as the third layer wiring 19c, and the wiring W3 is formed on the second insulating layer 17b. A conductive region 53 is formed over a region including a plurality of conductive regions 51 sandwiching the conductive region 51. The plurality of conductive regions 51 are electrically connected to the ground wiring layer WG of the fourth layer wiring 19d directly above by the via 21a penetrating the fourth insulating layer 17d formed corresponding to the planar shape of the conductive region 51. The via 21a is connected and penetrates the third insulating layer 17c formed corresponding to the planar shape of the conductive region 51, and is electrically connected to the conductive region 53 of the second layer wiring 19b directly below. Since the ground wiring layer WG is formed in a range that covers the wiring W3 and the plurality of conductive regions 51, the wiring W3 extends by the ground wiring layer WG, the via 21a, the conductive region 51, and the conductive region 53. Surrounded from a direction perpendicular to the direction, these vias 21a and conductive regions 51 and 53 are grounded via the ground wiring layer WG.

Further, the following via structure is added to the via structure formed by the via 21a and the conductive regions 51 and 53. That is, between the conductive region 53 and the semiconductor substrate 3, the via 21b penetrating the second insulating layer 17b, the conductive region 55 formed as the first layer wiring 19a, the via 21c penetrating the first insulating layer 17a, and An additional via structure is provided that includes a conductive region 57 formed on the semiconductor substrate 3. In addition, additional via structures are also provided. That is, between the conductive region 53 and the semiconductor substrate 3, the via 21d is formed in parallel with the via 21b through the second insulating layer 17b, the conductive region 59 formed as the first layer wiring 19a, and the first insulation. An additional via structure is provided that includes a via 21e penetrating the layer 17a and a conductive region 61 formed on the semiconductor substrate 3. With these additional via structures, the via structure including the via 21a is electrically connected to the conductive regions 55 and 59 on the first layer wiring 19a and the conductive regions 57 and 61 on the semiconductor substrate 3.

A plurality of these via structures and additional via structures are provided along the plurality of wirings for bias supply in the multilayer wiring layer 5. In FIG. 7, the solid line indicated by the reference numeral BS1 indicates the shape of the additional via structure formed by the vias 21b and 21c along the wiring W3, and the solid line indicated by the reference numeral BS2 in FIG. 7 indicates the shape of the via 21d and 21d along the wiring W3. The shape of the additional via structure formed by 21e is shown. In this way, the two additional via structures are formed so as to be staggered with each other along the wiring W3. Further, as shown in FIG. 8, in these additional via structures, the length of the vias 21b, 21c and the vias 21d, 21e along the wiring W3 is the wavelength λ of the RF signal to be processed by the microwave integrated circuit 1. Correspondingly, it is set shorter than λ / 8, and the arrangement spacing (gap) of the plurality of vias 21b, 21c and vias 21d, 21e along the wiring W3 is also set shorter than λ / 8. Further, the via structure including the via 21a may be formed in the same shape and arrangement.

Returning to FIG. 6, in the multilayer wiring layer 5, another via structure for electrically connecting the semiconductor substrate 3 to the fourth layer wiring 19d of the uppermost layer is also formed in the vicinity of the side portion thereof. That is, a plurality of conductive regions 63 are formed on the semiconductor substrate 3, and the conductive regions 65, 67, and 69 have shapes and ranges corresponding to the conductive regions 63 on the first to third insulating layers 17a to 17c, respectively. Are formed, and these plurality of conductive regions 63, 65, 67, 69 are electrically connected to the ground wiring layer WG via a plurality of vias 21f formed in the shapes and ranges corresponding to these. .. As shown by the solid line BS3 in FIG. 7, a plurality of these other via structures are formed along the respective sides 5a, 5b, 5c, 5d of the multilayer wiring layer 5, and are formed on the respective sides 5a, 5b, 5c, 5d. The length and spacing along are set shorter than λ / 8.

In the microwave integrated circuit 1 described above, the wiring W3 that supplies power to the plurality of amplification units has a plurality of vias 21a, second layer wirings 19b, and third layers that straddle the second layer to fourth layer wirings 19b to 19d. It is surrounded by conductive regions 53 and 51 on the layer wiring 19c, and the plurality of vias 21a and the conductive regions 53 and 51 are electrically connected to the ground wiring layer WG. Further, this via structure is connected to an additional via structure formed between the second layer wiring 19b and the semiconductor substrate 3. With such a via structure, electrical interference between a plurality of amplification units formed on the semiconductor substrate 3 is reduced. As a result, oscillation in the output signal can be effectively reduced. Specifically, such a via structure electrically shields the input of the low noise amplifier 31 from the wiring W1 (input of the power amplifier 35) connecting the driver amplifier 33 and the power amplifier 35. It is possible to reduce the oscillation in the output signal of the main series. In particular, the solder balls 9c having the role of output terminals P _OUT1 of solder balls 9a and main sequence having a role of input terminal P _IN is adjacent sides 5a, is provided on the 5c side (see FIG. 4), the According to the via structure of the embodiment, these solder balls 9a and 9c are electrically separated from each other. As a result, oscillation in the output signal can be reduced more effectively.

In particular, the length along the wiring of the via structure is shorter than the length of λ / 8 corresponding to the wavelength λ of the RF signal targeted by the microwave integrated circuit 1. According to such a configuration, it is possible to prevent the via structure from functioning as an antenna and picking up the RF signal, and it is possible to enhance the signal shielding effect of the plurality of via structures. Furthermore, since the spacing along the wiring of the plurality of via structures is also shorter than the length of λ / 8, the propagation of the RF signal between the plurality of via structures is prevented and the signal shielding effect due to the plurality of via structures is obtained. Can be increased, and oscillation in the output signal can be reduced more effectively.

Further, in the present embodiment, another via structure connecting the surface of the semiconductor substrate 3 to the fourth layer wiring 19d of the uppermost layer is also formed. By doing so, the signal shielding effect can be exhibited between the semiconductor substrate 3 and the fourth layer wiring 19d, and the oscillation in the output signal can be further reduced. In particular, since these other via structures are formed in a rectangular shape along the sides 5a, 5b, 5c, 5d of the multilayer wiring layer 5, the outside of the sides 5a, 5b, 5c, 5d of the multilayer wiring layer 5 is formed. It is possible to prevent the propagation of the RF signal between the input terminal and the output terminal (for example, between the two solder balls 9a and 9c).

Further, the plurality of via structures provided in the present embodiment are arranged in two rows in a staggered manner along the wiring. As a result, the shielding effect of the RF signal can be enhanced by reducing the gap through which the signal passes linearly due to the plurality of via structures arranged in parallel along the wiring. As a result, oscillation in the output signal can be reduced more effectively.

FIG. 9 is a graph showing the effect of preventing the oscillation of the output signal by the microwave integrated circuit 1 (isolation effect between terminals). Here, the intensity (isolation between terminals) (dB) of the oscillating component observed when the frequency of the RF signal processed in the main sequence is changed is shown in comparison with the comparative example not including the via structure. ing. According to this result, in the microwave integrated circuit 1, the oscillation intensity (isolation between terminals) is improved by about 5 dB at 38 GHz.

Although the principles of the present invention have been illustrated and described above in preferred embodiments, it will be appreciated by those skilled in the art that the invention may be modified in arrangement and detail without departing from such principles. The present invention is not limited to the specific configuration disclosed in the present embodiment. Therefore, we claim all amendments and changes that come from the claims and their spiritual scope.

In the above embodiment, the wiring for supplying bias in the multilayer wiring layer 5 is formed in the third layer wiring 19c, but other wiring layers other than the uppermost wiring layer 19d and the lowermost wiring layer 19a. May be formed in. In this case, the via structure surrounding the wiring is arranged corresponding to the position of the wiring.

Further, the plurality of via structures need not be electrically connected to both the uppermost wiring layer 19d and the lowermost wiring layer 19a, and may be connected to either one of them. Further, the ground wiring layer WG does not necessarily have to be formed in the uppermost wiring layer 19d, and may be formed in, for example, the lowermost wiring layer 19a. In that case, the plurality of via structures (including another via structure) are formed by being electrically connected to the ground wiring layer WG of the lowermost wiring layer 19a.

1 ... Microwave integrated circuit, _PIN ... Input terminal, P _OUT1 , P _OUT2 ... Output terminal, W2, W3 ... Wiring (power supply line), WG ... Ground wiring layer (conductive region), 17a to 17e ... 1st to 1st 5 layer insulating layer, 19a to 19d ... 1st to 4th layer wiring (wiring layer), 3 ... semiconductor substrate, 5 ... multilayer wiring layer, 5a, 5b ... one side, 9 ... solder ball, 21,21a to 21f ... via , 31, 37, 41 ... Low noise amplifier (amplification unit), 33, 43 ... Driver amplifier (amplification unit), 35, 45 ... Power amplifier (amplification unit), 51, 53, 55, 57, 59, 61, 63 , 65, 67, 69 ... Conductive region.

Claims (7)

With a semiconductor substrate
A plurality of amplification units formed in the semiconductor substrate, and
Of the plurality of wiring layers formed on the semiconductor substrate, a power supply line formed in one wiring layer excluding the uppermost wiring layer and the lowest wiring layer and supplying power to the plurality of amplification units, and
A plurality of conductive regions formed across the power supply line in the one wiring layer, and another conductive region formed in a region sandwiching the power supply line in the two wiring layers directly above and below the one wiring layer. And, with multiple vias connecting,
Have,
Each of the plurality of vias forms a via structure connected to at least one of the uppermost wiring layer and the lowermost wiring layer by a plurality of other vias.
Microwave integrated circuit. The length of each of the plurality of vias along the power line is shorter than the length of λ / 8 corresponding to the signal wavelength λ targeted by the microwave integrated circuit.
The microwave integrated circuit according to claim 1. The spacing of the plurality of vias along the power line is shorter than the length of λ / 8 corresponding to the signal wavelength λ.
The microwave integrated circuit according to claim 1 or 2. The plurality of vias are grounded via the uppermost wiring layer or the lowest wiring layer.
The microwave integrated circuit according to any one of claims 1 to 3. The semiconductor substrate has a rectangular planar shape, has a signal input terminal on one side of the rectangle, and has a signal output terminal on the other side adjacent to the one side.
The signal input terminal and the signal output terminal are electrically separated by the via structure.
The microwave integrated circuit according to any one of claims 1 to 4. Includes yet another plurality of vias that penetrate the plurality of wiring layers and connect the semiconductor substrate and the topmost wiring layer.
The microwave integrated circuit according to any one of claims 1 to 5. The via structure further includes a plurality of additional vias formed along the plurality of other vias, wherein the plurality of other vias and the plurality of additional vias are staggered with each other. ,
The microwave integrated circuit according to any one of claims 1 to 6.

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