A space-sharing inductor with a switch

Abstract

The present invention discloses a space-sharing inductor with a switch, the inductor comprising: an RDL metal layer as the top metal, an aluminum metal layer, used to make an LNA inductor; an M6 metal layer as a copper metal layer, used to make a bridge metal of an inductor of a PA and an LNA inductor; an M5 metal layer as a copper metal layer, used to make a bridge metal of a PA inductor; a dielectric barrier exists between the RDL metal layer and the M6 ​​metal layer, and an electrical connection is made through a PA metal plug; a dielectric barrier exists between the M6 ​​metal layer and the M5 metal layer, and an electrical connection is made through a Via5 metal plug, and a space-sharing inductor is realized by stacking two inductors. The present invention realizes a high quality factor, i.e., a high Q value, and the two inductors can work without interfering with each other, and effectively reduces the chip area.

Description

Technical Field

[0001] The invention belongs to integrated circuits and relates to the field of radio frequency integrated circuit design, in particular to a space-sharing inductor with a switch and used for TX and RX at the same time. Background Art

[0002] In wireless transceiver circuits, inductors are one of the indispensable components. With the development of advanced CMOS technology, RF transceiver chips are moving towards full integration, and on-chip spiral inductors have gradually become the main choice for RF integrated circuit design inductors. Due to the simple structure of on-chip spiral inductors, the performance parameters of the inductors can be freely designed, and the functions of baluns and transformers can be realized by stacking. Therefore, they are widely welcomed by circuit designers.

[0003] However, since chip area and cost are positively correlated, a larger inductor layout area results in higher chip cost. In the transceiver link, low noise amplifiers, power amplifiers, matching networks, and LC oscillators all require inductors to implement circuit functions, so multiple inductors are required, which greatly increases the chip area.

[0004] In the existing transceiver circuits, low noise amplifiers, power amplifiers, matching networks, etc. all use on-chip spiral inductors, which occupy a very large area on the inductor chip, which affects the cost of the chip. The existing technology mainly reduces the number of inductors used by a) inductor-free circuit design, b) using package binding wire inductors, or reduces the inductor area by c) T-Coil or MLS inductor design. The disadvantage of method a) is that it cannot obtain sufficient bandwidth filtering and gain, so the power consumption will increase. The disadvantage of method b) is that the inductance value of the package binding wire cannot be accurately controlled, resulting in a decrease in chip yield. The disadvantage of method c) is that the Q value of the inductor is low, which will increase the power consumption of the chip. Summary of the invention

[0005] The purpose of the present invention is to provide a space-shared inductor with a switch, which can stack the inductors of PA and LNA together to save area while ensuring a high quality factor, ie, a high Q value, of the inductor through space design.

[0006] The specific technical solution for achieving the purpose of the present invention is:

[0007] A space-sharing inductor with a switch, characterized in that the inductor comprises: an RDL metal layer as the top metal, which is an aluminum metal layer, and is used to make an LNA inductor; an M6 metal layer as a copper metal layer, and is used to make a bridge metal between an inductor of a PA and an LNA inductor; an M5 metal layer as a copper metal layer, and is used as a bridge metal for a PA inductor; a dielectric barrier exists between the RDL metal layer and the M6 ​​metal layer, and an electrical connection is made through a PA metal plug; a dielectric barrier exists between the M6 ​​metal layer and the M5 metal layer, and an electrical connection is made through a Via5 metal plug;

[0008] The RDL metal layer includes an RDL first interface, an RDL first metal layer body, an RDL second interface, an RDL third interface, an RDL second metal layer body and an RDL fourth interface; the RDL first metal layer body extends in a ring shape from the RDL first interface to the RDL second interface; the RDL second metal layer body extends in a ring shape from the RDL third interface to the RDL fourth interface;

[0009] The M6 ​​metal layer includes an M6 first interface, an M6 first metal layer body, an M6 second interface, an M6 third interface, an M6 second metal layer body, an M6 fourth interface, an M6 fifth interface, an M6 third metal layer and an M6 sixth interface; the M6 ​​first metal layer body extends in a ring shape from the M6 ​​first interface to the M6 ​​second interface; the M6 ​​second metal layer body extends in a ring shape from the M6 ​​third interface to the M6 ​​fourth interface; two interfaces of the M6 ​​third metal layer, namely the M6 ​​fifth interface and the M6 ​​sixth interface, are respectively located directly below the RDL second interface and the RDL third interface;

[0010] The M5 metal layer includes an M5 first interface, an M5 first metal body layer and an M5 second interface;

[0011] The RDL second interface is connected to the M6 ​​fifth interface through a PA metal plug, and the RDL third interface is connected to the M6 ​​sixth interface through a PA metal plug;

[0012] The M6 ​​second interface is connected to the M5 first interface through a Via5 metal plug, and the M6 ​​third interface is connected to the M5 second interface through a Via5 metal plug;

[0013] A switch T1 is provided between the first RDL interface and the fourth RDL interface; a switch T2 is provided between the first M6 interface and the fourth M6 interface.

[0014] The present invention uses the RDL layer to make a complete LNA inductor (with a higher Q value than the ordinary metal layer inductor) and uses the Cu metal top layer to complete the PA inductor (which can also obtain a high Q value). By utilizing the space design, the two inductors are not connected to each other and the high quality factor (high Q value) of the inductor is guaranteed.

[0015] Due to the circuit operating characteristics of the PA and LNA of the transceiver, the two modules will not work at the same time. Therefore, when one of the two inductors is working, the other one only exists as a metal wire or shielding wire, and does not affect the inductance performance of each other (the L value and Q value remain unchanged), so the circuit performance is not affected. In the transceiver, when the transmitter is turned on, the T2 switch at the output end of the LNA inductor is closed, and the mutual inductance eddy current will not affect the performance of the PA inductor. When the receiver is turned on, the T1 switch at the output end of the PA inductor is closed, and the mutual inductance eddy current will not affect the performance of the LNA inductor. Therefore, this stacked inductor with shared space is feasible in the transceiver.

[0016] An active switch circuit is added to each terminal of the two inductors. When the PA and LNA are working, the other inductor is closed respectively, so that the inductor itself becomes a floating material located below or above the inductor (the eddy currents are symmetrical and cancel each other out). In this way, the mutual influence is reduced to the lowest level.

[0017] The advantage of the present invention is that the LNA inductor and the PA inductor are made of two metal layers at the top of the circuit under the premise of sharing space, thereby achieving a high quality factor (high Q value), and the two inductors can work without interfering with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a plan view of the inductor structure of the present invention;

[0019] Figure 2 It is a three-dimensional diagram of the inductor structure of the present invention. DETAILED DESCRIPTION

[0020] As introduced in the background art, in existing transceiver circuits, low noise amplifiers, power amplifiers, matching networks, etc. all use on-chip spiral inductors. These inductors occupy a very large area on the chip, which affects the cost of the chip.

[0021] To solve the above problems, the present invention provides a space-shared inductor with a switch for both TX and RX. The inductor structure of the present invention includes two copper metal layers and a top aluminum metal layer stacked together. The copper metal layer is used as the metal wire of the PA inductor, and the aluminum metal layer is used as the metal wire of the LNA inductor. The inductor is closed or not by switches T1 and T2. Since the eddy currents in the closed inductor are symmetrical and will cancel each other out, when the switch is closed, the inductor will become a floating material and will not affect the characteristics of another inductor that is working. Therefore, the space-shared inductor of the present invention effectively reduces the area occupied while ensuring the inductor characteristics.

[0022] In order to make the above structure and advantages of the present invention more clearly understood, the specific implementation of the present invention is described in detail below with reference to the accompanying drawings.

[0023] The present invention provides a space-sharing inductor structure with a switch for both TX and RX. The specific structure is shown in FIG. Figure 1 and Figure 2 , Figure 1 is a plan view of the inductor structure of the present invention, Figure 2 It is a three-dimensional structural schematic diagram of the structure of the present invention, including:

[0024] The top RDL metal layer is an aluminum metal layer, and the shapes of the metal layer bodies 1 and 2 in the metal layer are close to two octagons. The metal layer body 1 includes a half octagonal outer ring, all octagonal inner rings and the connecting wires between the two, and the metal layer body 2 is the remaining octagonal outer ring. Excluding the connecting wires, the eight sides of the inner and outer metal layers 1 and 2 are parallel to each other. The RDL first interface a of the top metal layer body 1 is connected to the RDL second interface d of the metal layer body 2 through a switch T1.

[0025] The M6 ​​metal layer located below the top RDL metal layer is a copper metal layer. The two interfaces i and interface j of the M6 ​​third metal layer body 5 of the M6 ​​metal layer are connected to the second interface b of the top metal layer body 1 and the first interface c of the top metal layer body 2 through PA metal plugs 7 and PA metal plugs 8 respectively.

[0026] The shapes of the M6 ​​metal layer bodies 3 and 4 of the M6 ​​metal layer located below the top RDL metal layer are close to two octagons. The M6 ​​metal layer body 3 includes a half octagonal outer ring, a full octagonal inner ring and a connecting line between the two, and the M6 ​​metal layer body 4 is the remaining octagonal outer ring. Excluding the connecting line, the octagonal sides of the inner and outer M6 metal layers 3 and 4 are parallel to each other. The first interface e of the M6 ​​metal layer body 3 is connected to the second interface h of the M6 ​​metal layer body 4 through a switch T2.

[0027] The M5 metal layer below the M6 ​​metal layer is a copper metal layer. The two interfaces k and l of the M5 metal layer body 6 are connected to the second interface f of the M6 ​​metal layer body ring 3 and the first interface g of the M6 ​​metal layer body 4 through Via5 metal plugs 9 and 10 respectively.

[0028] It should be noted that the metal layers with different names must not be in contact with each other, and there needs to be a certain distance between the two metal layers.

[0029] The RDL first interface a and the RDL fourth interface d are two ports for LNA inductor access typing.

[0030] The M6 ​​first interface e and the M6 ​​fourth interface h are two ports for PA inductor access typing.

[0031] The switch T1 is an LNA inductor switch, connected between the RDL first interface a and the RDL fourth interface d, and controls whether the LNA inductor is connected to the circuit; when the T1 inductor is turned on, the LNA inductor is short-circuited and is not connected to the circuit; when the T1 inductor is closed, the LNA inductor works.

[0032] Switch T2 is a PA inductor switch, connected between the first interface e of M6 and the fourth interface h of M6, to control whether the PA inductor is connected to the circuit. When the T2 inductor is turned on, the PA inductor is short-circuited and is not connected to the circuit; when the T2 inductor is closed, the PA inductor works.

[0033] The PA inductor and LNA inductor will not work at the same time.

Claims

1. A space-sharing inductor with a switch, characterized in that: The spatial shared inductor includes: the RDL metal layer is the top metal, which is an aluminum metal layer and is used to make the inductor of the LNA; the M6 ​​metal layer is a copper metal layer and is used to make the bridge metal of the inductor of the PA and the LNA inductor; the M5 metal layer is a copper metal layer and is used as the bridge metal of the PA inductor; there is a dielectric barrier between the RDL metal layer and the M6 ​​metal layer, and they are electrically connected through the PA metal plug; there is a dielectric barrier between the M6 ​​metal layer and the M5 metal layer, and they are electrically connected through the Via5 metal plug; The RDL metal layer comprises an RDL first interface (a), an RDL first metal layer body (1), an RDL second interface (b), an RDL third interface (c), an RDL second metal layer body (2) and an RDL fourth interface (d); the RDL first metal layer body (1) extends in a ring shape from the RDL first interface (a) to the RDL second interface (b); the RDL second metal layer body (2) extends in a ring shape from the RDL third interface (c) to the RDL fourth interface (d); The M6 ​​metal layer comprises an M6 first interface (e), an M6 first metal layer body (3), an M6 second interface (f), an M6 third interface (g), an M6 second metal layer body (4), an M6 fourth interface (h), an M6 fifth interface (i), an M6 third metal layer (5) and an M6 sixth interface (j); the M6 ​​first metal layer body (3) extends in a ring shape from the M6 ​​first interface (e) to the M6 ​​second interface (f); the M6 ​​second metal layer body (4) extends in a ring shape from the M6 ​​third interface (g) to the M6 ​​fourth interface (h); two interfaces of the M6 ​​third metal layer (5), namely the M6 ​​fifth interface (i) and the M6 ​​sixth interface (j), are respectively located directly below the RDL second interface (b) and the RDL third interface (c); The M5 metal layer includes an M5 first interface (k), an M5 first metal body layer (6) and an M5 second interface (l); The RDL second interface (b) is connected to the M6 ​​fifth interface (i) through a PA metal plug (7), and the RDL third interface (c) is connected to the M6 ​​sixth interface (j) through a PA metal plug (8); The M6 ​​second interface (f) is connected to the M5 first interface (k) via a Via5 metal plug (9), and the M6 ​​third interface (g) is connected to the M5 second interface (l) via a Via5 metal plug (10); A switch T1 is provided between the RDL first interface (a) and the RDL fourth interface (d); a switch T2 is provided between the M6 ​​first interface (e) and the M6 ​​fourth interface (h).

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