CN115472381A - Space sharing inductance with switch - Google Patents

Abstract

The invention discloses a space sharing inductor with a switch, which comprises: the RDL metal layer is a top metal layer and an aluminum metal layer and is used for manufacturing the inductor of the LNA; the M6 metal layer is a copper metal layer and is used for manufacturing bridge metal of the PA inductor and the LNA inductor; the M5 metal layer is a copper metal layer and is used as bridging metal of the PA inductor; a dielectric barrier exists between the RDL metal layer and the M6 metal layer, and electric connection is carried out through a PA metal plug; and a medium barrier exists between the M6 metal layer and the M5 metal layer, the Via5 metal plug is used for electrical connection, and the two inductors are stacked to realize space sharing inductance. The invention realizes high quality factor, namely high Q value, and the two inductors can not interfere with each other when working, and the area of the chip is effectively reduced.

Description

Space sharing inductance with switch

Technical Field

The invention belongs to an integrated circuit, relates to the field of radio frequency integrated circuit design, and particularly relates to a space sharing inductor which is provided with a switch and used for TX and RX simultaneously.

Background

In a wireless transceiver circuit, an inductance is one of indispensable devices. With the development of advanced CMOS process, the chip of the radio frequency transceiver is developed towards full integration, and the on-chip spiral inductor gradually becomes the main choice for designing the inductor of the radio frequency integrated circuit. Due to the fact that the spiral inductor on the chip is simple in structure, performance parameters of the inductor can be freely designed, and functions of a balun, a transformer and the like can be achieved through stacking. And thus is widely popular with circuit designers.

However, since the chip area and the cost are positively correlated, the chip cost is high due to the large layout area of the inductor. In a transceiver link, a low noise amplifier, a power amplifier, a matching network and an LC oscillator all need inductors to realize circuit functions, so that a plurality of inductors are needed, and the chip area is greatly increased.

In the existing transceiver circuit, a low noise amplifier, a power amplifier, a matching network and the like respectively adopt on-chip spiral inductors, and the inductor chips occupy a very large area, namely, the cost of the chips is influenced. The prior art mainly reduces the number of inductors used by a) inductor-free circuit design, b) using package-bound wire inductors, or reduces the inductor area by c) inductor design such as T-Coil or MLS. The disadvantage of the method a) is that sufficient bandwidth filtering and gain cannot be obtained, and thus the consumed power consumption increases. The disadvantage of the method b) is that the inductance value of the package binding wire cannot be precisely controlled, resulting in the reduction of the chip yield. The disadvantage of c) is the low Q of the inductor, which leads to increased chip power consumption.

Disclosure of Invention

The invention aims to provide a space sharing inductor with a switch, and the inductors of a PA (power amplifier) and an LNA (low-noise amplifier) are stacked together to save area while ensuring high quality factor, namely high Q value of the inductor through space design.

The specific technical scheme for realizing the aim of the invention is as follows:

a space-sharing inductor with a switch, characterized in that said inductor comprises: the RDL metal layer is a top metal layer and an aluminum metal layer and is used for manufacturing the inductor of the LNA; the M6 metal layer is a copper metal layer and is used for manufacturing bridge metal of the PA inductor and the LNA inductor; the M5 metal layer is a copper metal layer and is used for bridging metal of the PA inductor; a dielectric barrier exists between the RDL metal layer and the M6 metal layer, and electric connection is carried out through a PA metal plug; a medium barrier exists between the M6 metal layer and the M5 metal layer, and the Via5 metal plug is used for electrical connection;

the RDL metal layer comprises 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 to the RDL second interface from the RDL first interface in a ring shape; the RDL second metal layer body extends to the RDL fourth interface from the RDL third interface in a ring shape;

the M6 metal layer comprises 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 body and an M6 sixth interface; the M6 first metal layer body extends from the M6 first interface to the M6 second interface in a ring shape; the M6 second metal layer body extends from the M6 third interface to the M6 fourth interface in a ring shape; two interfaces of the M6 third metal layer, namely an M6 fifth interface and an M6 sixth interface, are respectively positioned right below the RDL second interface and the RDL third interface;

the M5 metal layer comprises an M5 first interface, an M5 first metal layer and an M5 second interface;

the RDL second interface is connected with the M6 fifth interface through a PA metal plug, and the RDL third interface is connected with the M6 sixth interface through a PA metal plug;

the M6 second interface is connected with the M5 first interface through a Via5 metal plug, and the M6 third interface is connected with the M5 second interface through a Via5 metal plug;

a switch T1 is arranged between the RDL first interface and the RDL fourth interface; and a switch T2 is arranged between the M6 first interface and the M6 fourth interface.

The invention adopts the RDL layer to manufacture the complete LNA inductor (the Q value is higher than that of a common metal layer), and finishes manufacturing the PA inductor (the high Q value can be obtained) by using the Cu metal top layer. The mutual disconnection of the two inductors is realized by utilizing a space design, and the high quality factor (high Q value) of the inductors is ensured.

Due to the circuit operating characteristics of the PA and LNA of the transceiver, the two modules do not operate simultaneously, so that when one of the two inductors operates, the other inductor only exists as a section of metal wire or a shielded wire, and does not affect the inductance performance of each other (the L value and the Q value are both kept unchanged), so that the circuit performance is not affected. In the transceiver, when the transmitter is started to work, the T2 switch at the output end of the LNA inductor is closed, and the performance of the PA inductor cannot be influenced by mutual inductance eddy current. When the receiver is started to work, the T1 switch at the output end of the PA inductor is closed, and the mutual inductance eddy current does not influence the performance of the LNA inductor, so that the stacked inductor with the stacked shared space is feasible in the transceiver.

An active switch circuit is added to each terminal of the two inductors, and when the PA and the LNA work, the other inductor is closed respectively, so that the inductors are changed into a section of floating material below or above the inductors (eddy currents are symmetrical left and right and mutually offset). This reduces the mutual influence to a minimum level.

The invention has the advantages that the LNA inductor and the PA inductor are respectively made of two layers of metal at the top of the circuit on the premise of space sharing, high quality factor (high Q value) is realized, and the two inductors can not interfere with each other when working.

Drawings

FIG. 1 is a plan view of an inductor structure according to the present invention;

fig. 2 is a three-dimensional diagram of an inductor structure according to the present invention.

Detailed Description

As described in the background, in the existing transceiver circuit, the low noise amplifier, the power amplifier, the matching network, etc. each use an on-chip spiral inductor, and these inductors occupy a very large area on a chip, i.e. affect the cost of the chip.

In order to solve the above problems, the present invention provides a space-sharing inductor with a switch for TX and RX, where the inductor structure includes two copper metal layers stacked together and one top aluminum metal layer stacked together, the copper metal layer is used as a metal line of a PA inductor, and the aluminum metal layer is used as a metal line of a LNA inductor, and whether the inductor is turned on or off is determined by the switch T1 and the switch T2. Because the eddy current in the closed inductor is symmetrical left and right and can be mutually offset, when the switch is closed, the inductor becomes a floating material and cannot influence the inductance characteristic of the other inductor which is in operation, and therefore the space sharing inductor effectively reduces the occupied area while ensuring the inductance characteristic.

In order to make the aforementioned structure and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings.

The specific structure of the space-sharing inductor structure with switch and used for TX and RX of the present invention refers to fig. 1 and 2, fig. 1 is a plan view of the inductor structure of the present invention, fig. 2 is a schematic diagram of a three-dimensional structure of the present invention, including:

the RDL metal layer is an aluminum metal layer, and the shapes of the metal layer body 1 and the metal layer body 2 in the metal layer approach to two octagons. Wherein the metal layer body 1 comprises a half octagon outer ring, a whole octagon inner ring and a connecting line between the half octagon outer ring and the whole octagon inner ring, and the metal layer body 2 is the residual octagon outer ring. The eight sides of the inner and outer metal layers 1 and 2 are parallel to each other except for the connecting wires. The first interface a of the RDL of the top metal layer body 1 is connected with the second interface d of the RDL of the metal layer body 2 through a switch T1.

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

The shapes of the M6 metal layer 3 and the M6 metal layer 4 of the M6 metal layer under the top RDL metal layer approach to two octagons. Wherein the M6 metal layer body 3 comprises a half octagon outer ring, a whole octagon inner ring and a connecting line between the half octagon outer ring and the whole octagon inner ring, and the M6 metal layer body 4 is a residual octagon outer ring. The eight sides of the inner and outer M6 metal layers 3 and 4 are parallel to each other except for the connecting wires. The first interface e of the M6 metal layer 3 is connected with the second interface h of the M6 metal layer 4 through a switch T2.

The M5 metal layer located below the M6 metal layer is a copper metal layer, and the two interfaces k and l of the M5 metal layer 6 are connected to the second interface f of the M6 metal layer ring 3 and the first interface g of the M6 metal layer 4 through the Via5 metal plug 9 and the Via5 metal plug 10, respectively.

It should be noted that there should not be contact between the metal layers named differently, and a certain space is required between the two metal layers.

The RDL first interface a and the RDL fourth interface d are two ports keyed to LNA inductance access.

The first interface e of M6 and the fourth interface h of M6 are two ports of PA inductance access key.

The switch T1 is an LNA inductive switch, is connected between the RDL first interface a and the RDL fourth interface d, and controls whether the LNA inductance is connected to the circuit or not; when the T1 inductor is conducted, the LNA inductor is short-circuited and is not connected into a circuit; when the T1 inductor is closed, the LNA inductor operates.

The switch T2 is a PA inductance switch and is connected between the M6 first interface e and the M6 fourth interface h to control whether the PA inductance is connected into the circuit or not. When the T2 inductor is conducted, the PA inductor is short-circuited and is not connected into the circuit; when the T2 inductor is closed, the PA inductor operates.

The PA inductance and the LNA inductance do not operate simultaneously.

Claims (1)

1. A space-sharing inductor with a switch, said space-sharing inductor comprising: the RDL metal layer is a top metal layer and an aluminum metal layer and is used for manufacturing the inductor of the LNA; the M6 metal layer is a copper metal layer and is used for manufacturing bridge metal of the PA inductor and the LNA inductor; the M5 metal layer is a copper metal layer and is used for bridging metal of the PA inductor; a dielectric barrier exists between the RDL metal layer and the M6 metal layer, and electric connection is carried out through a PA metal plug; a medium barrier exists between the M6 metal layer and the M5 metal layer, and the Via5 metal plug is used for electrical connection;

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 from the RDL first interface (a) to the RDL second interface (b) in a ring shape; the RDL second metal layer body (2) extends from the RDL third interface (c) to the RDL fourth interface (d) in a ring shape;

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 body (5) and an M6 sixth interface (j); the M6 first metal layer body (3) annularly extends from the M6 first interface (e) to the M6 second interface (f); the M6 second metal layer body (4) extends from the M6 third interface (g) to the M6 fourth interface (h) in a ring shape; two interfaces of the M6 third metal layer (5), namely an M6 fifth interface (i) and an M6 sixth interface (j), are respectively positioned right below the RDL second interface (b) and the RDL third interface (c);

the M5 metal layer comprises an M5 first interface (k), an M5 first metal layer (6) and an M5 second interface (l);

the RDL second interface (b) is connected with the M6 fifth interface (i) through a PA metal plug (7), and the RDL third interface (c) is connected with the M6 sixth interface (j) through a PA metal plug (8);

the M6 second interface (f) is connected with the M5 first interface (k) through a Via5 metal plug (9), and the M6 third interface (g) is connected with the M5 second interface (l) through a Via5 metal plug (10);

a switch T1 is arranged between the RDL first interface (a) and the RDL fourth interface (d); and a switch T2 is arranged between the M6 first interface (e) and the M6 fourth interface (h).

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