CN115472381B - A space-sharing inductor with a switch - Google Patents

Abstract

The invention discloses a space sharing inductor with a switch, which comprises an RDL metal layer, an M6 metal layer, an M5 metal layer, a dielectric barrier and a Via5 metal plug, wherein the RDL metal layer is top metal and is an aluminum metal layer and is used for manufacturing an inductor of an LNA, the M6 metal layer is a copper metal layer and is used for manufacturing bridging metal of an inductor of a PA and an inductor of the LNA, the M5 metal layer is a copper metal layer and is used for bridging metal of the inductor of the PA, the RDL metal layer and the M6 metal layer are electrically connected through a PA metal plug, the M6 metal layer and the M5 metal layer are electrically connected through the dielectric barrier, and the space sharing inductor is realized through stacking the two inductors. The invention realizes high quality factor, namely high Q value, and the two inductors can not interfere with each other when working, and effectively reduces the chip area.

Description

Space sharing inductor with switch

Technical Field

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

Background

In a wireless transceiver circuit, inductance is one of indispensable devices. With the development of advanced CMOS processes, the development of radio frequency transceiver chips has been advanced toward full integration, and on-chip spiral inductors have become a major choice for designing inductors for radio frequency integrated circuits. The on-chip spiral inductor has a simple structure, and can freely design performance parameters of the inductor and realize functions of balun, transformer and the like by stacking. And are therefore widely welcome by 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 the transceiver link, the low noise amplifier, the power amplifier, the matching network and the 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, the low noise amplifier, the power amplifier, the matching network and the like all 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 uses a) inductance-free circuit design and b) packaging binding wire inductance to reduce the number of used inductors or uses c) T-Coil or MLS and other inductance designs to reduce the inductance area. The disadvantage of the approach a) is that adequate bandwidth filtering and gain is not available, so the consumed power consumption increases. The disadvantage of b) is that the inductance of the package bond wire cannot be precisely controlled, resulting in a reduced chip yield. The disadvantage of the method c) is that the Q value of the inductor is low, which leads to an increased chip power consumption.

Disclosure of Invention

The invention aims to provide a space sharing inductor with a switch, which is designed through space, and the inductors of a PA and an LNA are stacked together to save area while ensuring a high quality factor, namely a high Q value of the inductor.

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

A space sharing inductor with a switch is characterized by comprising an RDL metal layer, an M6 metal layer, an M5 metal layer, a dielectric barrier, an M6 metal layer, a dielectric barrier and a Via5 metal plug, wherein the RDL metal layer is top metal and is an aluminum metal layer and is used for manufacturing an inductor of an LNA;

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, wherein the RDL first metal layer body extends from the RDL first interface to the RDL second 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 and an M6 sixth interface, wherein 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, and two interfaces of the M6 third metal layer, namely the M6 fifth interface and the M6 sixth interface, are respectively positioned under the RDL second interface and the RDL third interface;

The M5 metal layer comprises an M5 first interface, an M5 first metal body layer and an M5 second interface;

the RDL second interface is connected with the M6 fifth interface through the PA metal plug, and the RDL third interface is connected with the M6 sixth interface through the 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 RDL layer to make complete LNA inductance (Q value is higher than that of common metal layer inductance), and uses Cu metal top layer to make PA inductance (high Q value can be obtained). By means of space design, the mutual disconnection of the two inductors is realized, and the high quality factor (high Q value) of the inductors is ensured.

Because the circuit operating characteristics of the PA and LNA of the transceiver do not operate simultaneously, the two inductors are present as a section of wire or shield only when one of them is operating, and do not affect each other's inductance performance (both L and Q values remain unchanged), so the circuit performance is not affected. In a transceiver, when operating at transmitter on, the T2 switch at the output of the LNA inductor is closed, and no mutual inductance eddy currents will affect the performance of the PA inductor. When the receiver is started to work, the T1 switch at the output end of the PA inductor is closed, and the performance of the LNA inductor is not affected by mutual inductance eddy current, so that the stacking inductor with a stacking shared space is feasible in the transceiver.

An active switching circuit is added to the respective terminal of the two inductors, and the other inductor is closed when the PA and the LNA are in operation, respectively, so that the inductor itself becomes a section of floating material (eddy currents are bilaterally symmetrical and cancel each other) located below or above the inductor. Thus influencing each other reduced to a minimum level.

The invention has the advantages that the LNA inductor and the PA inductor are respectively manufactured by two layers of metals at the top of the circuit on the premise of space sharing, so that 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 view 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, and the like each use on-chip spiral inductors, and these inductor chips occupy a very large area, that is, 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, wherein the inductor structure of the present invention comprises two copper metal layers and a top aluminum metal layer stacked, the copper metal layer is used as the metal line of the PA inductor, the aluminum metal layer is used as the metal line of the LNA inductor, and the switch T1 and the switch T2 determine whether the inductor is closed. Because eddy currents in the closed inductor are bilaterally symmetrical and can offset each other, after the switch is closed, the inductor becomes a floating material and the inductance characteristic of the other inductor in operation cannot be influenced, so that the space sharing inductor of the invention effectively reduces occupied area while ensuring the inductance characteristic.

In order that the above-recited structure and advantages of the present invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings.

The invention relates to a space sharing inductance structure with a switch for TX and RX, which is concretely provided with reference to fig. 1 and 2, wherein fig. 1 is a plan view of the inductance structure, and fig. 2 is a three-dimensional structure schematic diagram of the structure, and the space sharing inductance structure comprises:

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 are similar to two octagons. The metal layer body 1 comprises a half-octagon outer ring, all octagon inner rings and connecting lines between the half-octagon outer ring and all octagon inner rings, and the metal layer body 2 is a residual octagon outer ring. The connection lines are removed, and the octagons 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 with the RDL second interface d of the metal layer body 2 through a switch T1.

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

The M6 metal layer body 3, the M6 metal layer body 4 of the M6 metal layer located below the top RDL metal layer is shaped like two octagons. The M6 metal layer body 3 comprises a half octagonal outer ring, all octagonal inner rings and connecting lines between the half octagonal outer ring and the half octagonal inner rings, and the M6 metal layer body 4 is the rest octagonal 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 lines. The first interface e of the M6 metal layer body 3 is connected with the second interface h of the M6 metal layer body 4 through a switch T2.

The M5 metal layer below the M6 metal layer is a copper metal layer, and two interfaces k and l of the M5 metal layer body 6 are respectively connected with 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 the Via5 metal plug 9 and the Via5 metal plug 10.

It should be noted that, there must not be contact between the various named metal layers, 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 for LNA inductance access keying.

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

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

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

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

Claims (1)

1. A space sharing inductor with a switch is characterized by comprising an RDL metal layer, an M6 metal layer, an M5 metal layer, a dielectric barrier and a Via5 metal plug, wherein the RDL metal layer is top metal and is an aluminum metal layer and is used for manufacturing an inductor of an LNA;

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), wherein the RDL first metal layer body (1) extends from the RDL first interface (a) to the RDL second interface (b) in a ring shape, and 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 (5) and an M6 sixth interface (j), wherein the M6 first metal layer body (3) extends from the M6 first interface (e) to the M6 second interface (f) in a ring shape, the M6 second metal layer body (4) extends from the M6 third interface (g) to the M6 fourth interface (h) in a ring shape, and two interfaces of the M6 third metal layer (5), namely the M6 fifth interface (i) and the M6 sixth interface (j), are respectively positioned under 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 body layer (6) and an M5 second interface (l);

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