CN214898440U

CN214898440U - Bonding wire inductor for improving VCO low phase noise level

Info

Publication number: CN214898440U
Application number: CN202121508592.XU
Authority: CN
Inventors: 吴齐发; 方敏
Original assignee: Hefei Ruipukang Integrated Circuit Co ltd
Current assignee: Hefei Ruipukang Integrated Circuit Co ltd
Priority date: 2021-07-02
Filing date: 2021-07-02
Publication date: 2021-11-26
Anticipated expiration: 2031-07-02

Abstract

The utility model discloses an improve bonding wire inductance of VCO low phase noise level, including first pad group, second pad group, first pad group, second pad group set up in the top layer of VCO circuit board, first pad group includes 2 or a plurality of pads, second pad group include with the pad of first pad group corresponding quantity, every the pad in the first pad group pass through the bonding wire with its pad that corresponds in the second pad group is connected; the utility model provides an utilize the chip bonding line, through the method of routing between PAD, realize the inductance at the chip top layer, utilize the very low resistivity of bonding line and good electromigration characteristic to improve the Q value of inductance.

Description

Bonding wire inductor for improving VCO low phase noise level

Technical Field

The utility model relates to a low noise amplifier technical field specifically is an improve bonding wire inductance of VCO low phase noise level.

Background

The frequency synthesizer is used as a local oscillator generating circuit, exists in a radio frequency receiving and transmitting system, and plays an extremely important role in modern radio frequency communication. Local oscillator signals in radio frequency transceivers need to have precise frequencies, low phase noise and spurs, and fast response times. The frequency synthesizer generally consists of a phase locked loop that determines the in-band phase noise of the local oscillator and a Voltage Controlled Oscillator (VCO) whose out-of-band noise depends on the phase noise level of the VCO.

In order to obtain low phase noise performance, a VCO circuit generally adopts an inductor-capacitor resonant structure, that is, the VCO circuit is composed of an active device for providing energy and an inductor-capacitor resonator, the active device continuously provides energy to the resonator, and the energy performs mutual conversion between electric energy and magnetic energy in the resonator, so as to form periodic oscillation, and the Q value of the resonant circuit determines the phase noise level that the VCO can achieve.

In a modern CMOS (complementary metal oxide semiconductor) process, an inductance-capacitance oscillator generally adopts an on-chip integrated inductor and a capacitor, and the on-chip inductor is realized by a top copper metal wiring layer far away from a substrate. Analysis of inductance data provided by foundries shows that the Q value of the inductor is about 20 at 4GHz, the Q value of the on-chip capacitor is above 300, the Q value of the resonant circuit is determined by the inductor, and the limited Q value of the inductor severely limits the phase noise level which can be achieved by the VCO.

In order to improve the phase noise of VCO, need improve the Q value of inductance in the VCO on the piece, the utility model provides an utilize the chip bonding wire, through the method of routing between PAD, realize the inductance at the chip top layer, utilize the very low resistivity of bonding wire and good anti electromigration characteristic to improve the Q value of inductance.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an improve bonding wire inductance of VCO low phase noise level, cover the frequency channel width, do not have inductance, simple structure, can conveniently realize with the antenna between impedance match.

In order to achieve the above object, the utility model provides a following technical scheme: a bonding wire inductor for improving the low phase noise level of a VCO (voltage controlled oscillator) comprises a first bonding pad group and a second bonding pad group, wherein the first bonding pad group and the second bonding pad group are arranged on the top layer of a VCO circuit board, the first bonding pad group comprises 2 or more bonding pads, the second bonding pad group comprises bonding pads with the number corresponding to that of the first bonding pad group, and the bonding pads in each first bonding pad group are connected with the corresponding bonding pads in the second bonding pad group through bonding wires;

when the first bonding pad group comprises 2 bonding pads, the 2 bonding pads are connected through a metal wire on the top layer of the VCO circuit board, and the 2 bonding pads in the second bonding pad group are respectively connected with a required inductance access pin in the VCO circuit board through the metal wire;

when the first bonding pad group comprises a plurality of bonding pads, 2 bonding pads in the second bonding pad group are respectively connected with a required inductance access pin in the VCO circuit board through metal wires, and bonding pads corresponding to the 2 bonding pads in the first bonding pad group are connected with other bonding pads in the first bonding pad group and other bonding pads in the second bonding pad group in a staggered mode to form series connection.

Preferably, when the first bonding pad group includes 4 bonding pads, the second bonding pad group also includes 4 bonding pads, 2 bonding pads arranged in the middle of the second bonding pad group are respectively connected with a required inductance access pin in the VCO circuit board through a metal wire, the bonding pad corresponding to the 2 bonding pads in the first bonding pad group is connected with the bonding pad adjacent to the bonding pad through the metal wire on the top layer of the VCO circuit board, and the other 2 bonding pads of the second bonding pad group are also connected through the metal wire on the top layer of the VCO circuit board.

Preferably, the bonding line is at least one or more of a straight bonding line, a diagonal bonding line and a curved bonding line.

Preferably, the positions of the bonding pads in the first bonding pad group and the second bonding pad group are adjusted according to the allowable range of the bonding wire torque.

Preferably, the VCO circuit board below the pad is capable of placing circuitry.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the utility model discloses a bonding wire inductance adopts the crisscross mode of establishing ties the pad of bonding wire and metal wire, realizes the inductance at the chip top layer, utilizes the extremely low resistivity of bonding wire and good anti electromigration characteristic to improve the Q value of inductance; in addition, the mode that bonding wires and metal wires are connected in series with bonding pads in a staggered mode is adopted, the expansion of the inductance of the bonding wires can be facilitated, the control of the length and the arch height of the bonding wires is facilitated, and the error of the inductance of the chip can be controlled within 5%.

2. The utility model discloses still through the bonding scheme that reachs after communicating with the encapsulation factory, the bonding line moment of torsion of different encapsulation factories is adjustable, just so can not adopt subtend straight line bonding mode, can expand the slash bonding, and the bonding goes out different figures to obtain the inductance of equidimension not, the PAD of chip need not the straight line relatively place simultaneously, adjusts the PAD position in bonding line moment of torsion allowed range, can improve chip PAD utilization ratio.

3. The utility model discloses a bonding wire inductance's area is little, can place the circuit under the pad, does not occupy chip effective area basically, can improve the area utilization of chip to the cost is very low, and preparation simple process can use widely on a large scale.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a diagram illustrating a structure of a general bonded bond wire inductor according to the present invention;

fig. 2 is a diagram illustrating an inductance structure of the bonding wire of the present invention;

in the figure: 1. a first pad group; 2. a second pad group; 3. a bonding wire; 4. a metal wire;

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The utility model provides a technical scheme: as shown in fig. 1-2, a bonding wire inductor for improving a low phase noise level of a VCO includes a first pad group 1 and a second pad group 2, where the first pad group 1 and the second pad group 2 are disposed on a top layer of a VCO circuit board, the first pad group 1 includes 2 or more pads, the second pad group 2 includes pads corresponding to the first pad group 1 in number, and the pads in each first pad group 1 are connected to their corresponding pads in the second pad group 2 through bonding wires 3.

As shown in fig. 1, when the first PAD group 1 includes 2 PADs (P3\ P4), the 2 PADs (P3\ P4) are connected through the metal line 4 on the top layer of the VCO circuit board, and the 2 PADs (P1\ P2) in the second PAD group 2 are respectively connected with the required inductance access pin in the VCO circuit board through the metal line 4, and at this time, the inductance between the two PADs (i.e., PADs) of P1/P2 is formed.

When the first bonding pad group 1 comprises a plurality of bonding pads, 2 bonding pads in the second bonding pad group 2 are respectively connected with the required inductance access pins in the VCO circuit board through the metal wires 4, and the bonding pads corresponding to the 2 bonding pads in the first bonding pad group 1 are connected with other bonding pads in the first bonding pad group 1 and other bonding pads in the second bonding pad group 2 in a staggered manner to form a series connection, which is an expanded bonding pad connection manner.

As shown in fig. 2, when the first PAD group 1 includes 4 PADs, the second PAD group 2 also includes 4 PADs, 2 PADs (P1\ P2) disposed in the middle of the second PAD group 2 are respectively connected to a required inductance access pin in the VCO circuit board through metal lines 4, a PAD (P3\ P4) corresponding to the 2 PADs (P1\ P2) in the first PAD group 1 is connected to a PAD (P5\ P6) adjacent to the PAD in the first PAD group 1 through a metal line 4 on the top layer of the VCO circuit board, and the other 2 PADs (P7\ P8) in the second PAD group 2 are also connected through a metal line 4 on the top layer of the VCO circuit board, so that an inductance between the two PADs (i.e., PADs) of P1/P2 is formed.

In the chip layout design stage, two bonding pads (P1/P2) are reserved at the place where the inductor is required to be accessed in a VCO circuit and are used as inductor access points for connecting pins of the inductor required in the VCO circuit board, when the chip is packaged, the bonding pads are connected in series according to the routing mode shown in figure 1 or figure 2, the inductor can be generated between the two bonding pads P1/P2, and if the length, the arch height and the torque of a bonding wire are controlled, the inductor between 0.5nH and 5nH can be obtained. The method can also adopt a mode of connecting bonding wires and metal wires in series in a staggered mode, the length and the arch height of the bonding wires can be accurately controlled, the inductance error of a chip can be controlled within 5%, because most LC VCOs adopt a switched capacitor array, the tuning range is improved, a larger margin is reserved during design, and the correct frequency output by the VCO can be ensured by combining an AFC (auto frequency calibration) technology.

The utility model provides an adopt bonding wire inductance to replace on-chip inductance, carry out PAD (PAD) according to the routing mode on the figure 1-2 and distribute to thereby carry out the preparation of bonding connection realization high Q value inductance.

According to the method, through a bonding scheme obtained after communication with packaging factories, the bonding wire torques of different packaging factories are adjustable, so that the method can be expanded to oblique line bonding without adopting an opposite straight line bonding mode, different patterns are bonded, inductors with different sizes are obtained, simultaneously, PADs of chips are not required to be placed in a straight line opposite mode, the PAD positions are adjusted within the allowable range of the bonding wire torques, and the utilization rate of the PADs of the chips can be improved.

The inductor adopts a bonding wire connection mode, is positioned on the top layer of the VCO chip, is positioned above the passivation layer and is far away from the substrate, so the substrate loss is very small; secondly, in order to improve the Q value of the inductor in the modern process, a doped barrier layer is adopted at the place where the inductor is manufactured, the substrate resistance is improved, in order to prevent interference, other circuits are not placed below and at the periphery of the inductor, and the inductor occupies a larger area; because the inductance metal adopts the bonding wire, the diameter is generally more than 0.7mil, the thickness of the metal wire in the chip is far higher, the resistance is extremely low, the series parasitic resistance of the inductance is greatly reduced, and the Q value is very high.

The high-Q value inductor is formed through the bonding wire, the inductor can be independently manufactured through other processes such as IPD (integrated digital phase-locked loop) and the like, and then the design work of the low-phase noise VCO is completed through bonding or TSV connection.

In the description of the present invention, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A bond wire inductor for increasing a low phase noise level of a VCO, comprising: the VCO circuit board comprises a first bonding pad group (1) and a second bonding pad group (2), wherein the first bonding pad group (1) and the second bonding pad group (2) are arranged on the top layer of the VCO circuit board, the first bonding pad group (1) comprises 2 or more bonding pads, the second bonding pad group (2) comprises bonding pads with the number corresponding to that of the first bonding pad group (1), and the bonding pads in each first bonding pad group (1) are connected with the corresponding bonding pads in the second bonding pad group (2) through bonding wires (3);

when the first bonding pad group (1) comprises 2 bonding pads, the 2 bonding pads are connected through a metal wire (4) on the top layer of the VCO circuit board, and the 2 bonding pads in the second bonding pad group (2) are respectively connected with a required inductance access pin in the VCO circuit board through the metal wire (4);

when the first bonding pad group (1) comprises a plurality of bonding pads, 2 bonding pads in the second bonding pad group (2) are respectively connected with a required inductance access pin in the VCO circuit board through metal wires (4), and bonding pads corresponding to the 2 bonding pads in the first bonding pad group (1) are connected with other bonding pads in the first bonding pad group (1) and other bonding pads in the second bonding pad group (2) in a staggered mode to form series connection.

2. Bond wire (3) inductance to improve VCO low phase noise level according to claim 1, characterized in that: when the first bonding pad group (1) comprises 4 bonding pads, the second bonding pad group (2) also comprises 4 bonding pads, 2 bonding pads arranged in the middle of the second bonding pad group (2) are respectively connected with a required inductance access pin in the VCO circuit board through metal wires (4), bonding pads corresponding to the 2 bonding pads in the first bonding pad group (1) are connected with the adjacent bonding pads through the metal wires (4) on the top layer of the VCO circuit board, and the other 2 bonding pads of the second bonding pad group (2) are also connected through the metal wires (4) on the top layer of the VCO circuit board.

3. The bond wire inductance for increasing a low phase noise level of a VCO of claim 1 wherein: the bonding wire (3) at least adopts one or more of a straight bonding wire, a diagonal bonding wire and a curve bonding wire.

4. The bond wire inductance for increasing a low phase noise level of a VCO of claim 1 wherein: the positions of the bonding pads in the first bonding pad group (1) and the second bonding pad group (2) are adjusted and set within a torque allowable range according to the bonding wire (3).

5. The bond wire inductance for increasing a low phase noise level of a VCO of claim 1 wherein: the VCO circuit board under the pad can place circuitry.