CN110429072A - A flip chip radio frequency chip and a radio frequency device - Google Patents

Abstract

The invention discloses a flip-chip radio frequency chip, comprising a radio frequency bare chip and a substrate; the radio frequency bare chip is located on the surface of the substrate, and a surface of the radio frequency bare chip facing the substrate is provided with first signal pins, and the first signal pins pass through the first conductive The post is fixed on the side surface of the substrate facing the radio frequency bare chip; the conductive line layer of the substrate is provided with a conductive line for providing a preset matching inductance. The above RF bare chip is specifically mounted on the surface of the substrate in a flip-chip manner, and the heat generated during the information transfer process is mainly concentrated in the first conductive column. Because the first conductive column has a certain diameter, the heat dissipation is high, and the reliability is high and not easily damaged, so that the flip-chip radio frequency chip has high heat dissipation and reliability. The present invention also provides a radio frequency device, which also has the above beneficial effects.

Description

A flip chip radio frequency chip and a radio frequency device

technical field

The present invention relates to the technical field of communications, in particular to a flip-chip radio frequency chip and a radio frequency device.

Background technique

The fifth generation (5G) mobile communication standard is advancing in an orderly manner, and the next generation of mobile terminals such as smart phones, tablet computers and wearable devices will definitely need to support more working modes and frequency bands. In addition, to support such a wide variety of wireless communication protocols, multiple antenna designs are increasingly being adopted to achieve multiple-input multiple-output (MIMO) operation for high data rates, increased sensitivity, and avoidance of crosstalk.

However, in the prior art, especially radio frequency chips applied to the front end, such as radio frequency switches, have poor heat dissipation and low reliability. Therefore, how to improve the heat dissipation and reliability of the radio frequency chip is an urgent problem to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a flip-chip radio frequency chip with high heat dissipation and reliability; another object of the present invention is to provide a radio frequency device with high heat dissipation and reliability.

In order to solve the above technical problems, the present invention provides a flip-chip radio frequency chip, including a radio frequency bare chip and a substrate;

The radio frequency die is located on the surface of the substrate, and a surface of the radio frequency die facing the substrate is provided with a first signal pin, and the first signal pin is fixed to the substrate through a first conductive column and faces the substrate. A surface of one side of the radio frequency bare chip; a conductive line for providing a preset matching inductance is arranged in the conductive circuit layer of the substrate.

Optionally, the first conductive column is a copper column.

Optionally, the diameter of the cross section of the copper column is not greater than 1 mm.

Optionally, a side surface of the substrate facing away from the RF die has second signal pins, and a surface of the second signal pins is provided with second conductive pillars.

Optionally, the second signal pin is a tin column.

Optionally, the metal layers in the substrate are all provided with conductive lines for transmitting signals in the radio frequency die.

The present invention also provides a radio frequency device, comprising a circuit board and the flip-chip radio frequency chip according to any one of the above; the flip-chip radio frequency chip is communicatively connected to the circuit board.

A flip-chip radio frequency chip provided by the present invention includes a radio frequency bare chip and a substrate; the radio frequency bare chip is located on the surface of the substrate, and the surface of the side surface of the radio frequency bare chip facing the substrate is provided with a first signal pin, and the first signal pin passes through the first signal pin. The conductive column is fixed on the surface of the substrate on the side facing the radio frequency bare chip; the conductive line layer of the substrate is provided with a conductive line for providing a preset matching inductance. The above-mentioned RF die is mounted on the surface of the substrate in a flip-chip manner. The RF die communicates with the substrate through the first conductive column, and the corresponding heat generated during the information transfer process is mainly concentrated in the first conductive column. Because the first conductive column has a certain diameter, the heat dissipation is high, and the reliability is high and not easy to be damaged, so that the flip-chip RF chip has high heat dissipation and reliability; The volume of the radio frequency chip can be effectively reduced, which is conducive to the improvement of the integration degree of the radio frequency chip; since the bonding wire in the prior art is eliminated, in this application, a conductive circuit layer of the substrate is provided to provide a preset matching inductance conductive traces to match the parasitic capacitance introduced by the RF die.

The present invention also provides a radio frequency device, which also has the above beneficial effects, and will not be repeated here.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following will briefly introduce the accompanying drawings used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

1 is a schematic structural diagram of a radio frequency chip in the prior art;

Fig. 2 is the top view structure schematic diagram of Fig. 1;

3 is a schematic structural diagram of a flip-chip radio frequency chip according to an embodiment of the present invention;

Fig. 4 is the side view structure schematic diagram of Fig. 3;

Fig. 5 is the top view structure schematic diagram of Fig. 3;

6 is a schematic structural diagram of a specific flip-chip radio frequency chip provided by an embodiment of the present invention;

FIG. 7 is a schematic side view of the structure of FIG. 6 .

In the figure: 1. RF bare chip, 2. Substrate, 21. Conductive circuit layer, 3. First conductive column, 4. Second conductive column.

Detailed ways

The core of the present invention is to provide a flip chip radio frequency chip. Please refer to FIG. 1 and FIG. 2 , FIG. 1 is a schematic structural diagram of a radio frequency chip in the prior art; FIG. 2 is a top-view structural schematic diagram of FIG. 1 . Referring to FIG. 1 and FIG. 2 , in the prior art, the RF die is usually mounted on the surface of the substrate, the RF die is connected to the substrate through a bonding wire, and the electrical signal generated by the RF die will be transmitted to the substrate through the bonding wire . At this time, the heat generated in the information transfer process is mainly concentrated in the bonding wire. Because the bonding wire is very thin, the heat dissipation of the radio frequency chip is poor; at the same time, because the bonding wire is exposed above the substrate, the reliability of the radio frequency chip is low.

The flip-chip radio frequency chip provided by the present invention includes a radio frequency die and a substrate; the radio frequency die is located on the surface of the substrate, and the surface of the radio frequency die facing the substrate is provided with a first signal pin, and the first signal pin passes through the first signal pin. A conductive column is fixed on the surface of the substrate facing the side of the radio frequency bare chip; the conductive line layer of the substrate is provided with a conductive line for providing a preset matching inductance. The above-mentioned RF die is mounted on the surface of the substrate in a flip-chip manner. The RF die communicates with the substrate through the first conductive column, and the corresponding heat generated during the information transfer process is mainly concentrated in the first conductive column. Because the first conductive column has a certain diameter, the heat dissipation is high, and the reliability is high and not easy to be damaged, so that the flip-chip RF chip has high heat dissipation and reliability; The volume of the radio frequency chip can be effectively reduced, which is conducive to the improvement of the integration degree of the radio frequency chip; since the bonding wire in the prior art is eliminated, in this application, a conductive circuit layer of the substrate is provided to provide a preset matching inductance conductive traces to match the parasitic capacitance introduced by the RF die.

In order to make those skilled in the art better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 3 , FIG. 4 and FIG. 5 . FIG. 3 is a schematic structural diagram of a flip-chip RF chip according to an embodiment of the present invention; FIG. 4 is a side view structural schematic diagram of FIG. 3 ; FIG. 5 is a top-view structure of FIG. 3 Schematic.

Referring to FIG. 3 , FIG. 4 and FIG. 5 , in an embodiment of the present invention, a flip-chip radio frequency chip includes a radio frequency die 1 and a substrate 2 ; the radio frequency die 1 is located on the surface of the substrate 2 , and the radio frequency die 1 faces One side surface of the substrate 2 is provided with first signal pins, and the first signal pins are fixed to the side surface of the substrate 2 facing the RF die 1 through the first conductive posts 3; Conductive lines for providing preset matching inductance are provided in the conductive line layer 21 .

The above-mentioned radio frequency bare chip 1 , namely Die, is a component mainly used for realizing the function of a radio frequency chip in the embodiment of the present invention. For the specific structure of the radio frequency die 1 , reference may be made to the prior art, which will not be repeated here. In the embodiment of the present invention, the radio frequency die 1 is specifically packaged on the surface of the substrate 2 , that is, the radio frequency die 1 is located on the surface of the substrate 2 and is fixedly connected to the substrate 2 . Specifically, the surface of the radio frequency die 1 facing the substrate 2 is provided with first signal pins, and the first signal pins are fixed on the surface of the substrate 2 facing the radio frequency die 1 through the first conductive posts 3 , that is, the above-mentioned radio frequency The bare chip 1 is flip-chipped on the surface of the substrate 2 . It should be noted that the above-mentioned first signal pins generally do not have protruding pins, that is, the above-mentioned first signal pins are generally in a sheet shape and are located on the side surface of the RF die 1 facing the substrate 2 . At this time, the electrical signal generated by the communication between the RF die 1 and the substrate 2 is transmitted through the first conductive column 3 , and the copper column is one of the main heat concentrations of the RF chip during operation.

In the embodiment of the present invention, the first conductive column 3 is usually a copper column, and the copper column has good electrical conductivity, thermal conductivity, and low price, which can make the radio frequency chip provided by the embodiment of the present invention have sufficient heat dissipation performance At the same time, the production cost of the RF chip is effectively controlled. Usually, the diameter of the cross-section of the copper pillar is not greater than 1 mm, that is, the diameter of the cross-section of the copper pillar is usually in the order of microns. The above-mentioned copper pillars are usually grown between the RF die 1 and the substrate 2 through a growth process, and play the roles of fixing, supporting, and transmitting information.

In the embodiment of the present invention, the conductive line layer 21 of the substrate 2 is provided with a conductive line for providing a preset matching inductance. The above-mentioned substrate 2 is provided with a conductive circuit layer 21 . As the name implies, the above-mentioned conductive circuit layer 21 is provided with conductive lines. The conductive lines are generally used to transmit electrical signals in the substrate 2 , ie, electrical signals generated by the RF die 1 . Due to the structure of the radio frequency die 1 , specifically due to the parasitic coupling effect of the metal connecting lines in the radio frequency die 1 , a capacitive effect that is not conducive to the performance of the radio frequency chip, that is, parasitic capacitance is introduced.

In the embodiment of the present invention, in order to better complete port matching and achieve good insertion loss and isolation performance, it is necessary to set an inductance matching the above-mentioned parasitic capacitance in the radio frequency chip, that is, a preset matching inductance. The inductance value of the preset matching inductance needs to form a good match with the capacitance value of the parasitic capacitance introduced by the RF bare chip 1 . The specific inductance value of the preset matching inductance needs to be set according to the actual situation, which is not specifically limited here. In the embodiment of the present invention, the conductive line layer 21 in the substrate 2 is specifically provided with a conductive line corresponding to the preset matching inductance, so as to realize the setting of the preset matching inductance, that is, the above-mentioned conductive line can be used as the preset matching inductance, Therefore, the radio frequency chip has a matching inductance value corresponding to the parasitic capacitance value.

It should be noted that, in the prior art, a traditional bonding wire generally has an equivalent length of 1 mm equal to an inductance value of 1 nH, while a bonding wire of a certain equivalent length generally exists between the RF die 1 and the substrate 2 , the equivalent length of the bonding wire is at least the length that the substrate 2 needs to increase relative to the RF bare chip 1 . In the embodiment of the present invention, since the radio frequency die 1 is flip-chipped on the surface of the substrate 2, no bonding wire is provided, so that the length of the substrate 2 in the flip-chip radio frequency chip provided by the embodiment of the present invention can be the same as that of the radio frequency die. The lengths of 1 are approximately equal, thereby reducing the length of the radio frequency chip, thereby reducing the area of the radio frequency die 1 .

A flip-chip radio frequency chip provided by an embodiment of the present invention includes a radio frequency die 1 and a substrate 2; the radio frequency die 1 is located on the surface of the substrate 2, and the radio frequency die 1 is provided with a first signal pin on the side of the surface facing the substrate 2, The first signal pin is fixed to the surface of the substrate 2 on the side facing the RF die 1 through the first conductive column 3 ; the conductive line layer 21 of the substrate 2 is provided with a conductive line for providing a preset matching inductance. The above RF bare chip 1 is specifically mounted on the surface of the substrate 2 in a flip-chip manner. The RF bare chip 1 communicates with the substrate 2 through the first conductive column 3, and the corresponding heat generated during the information transfer process is mainly concentrated in the first conductive column. in a conductive column 3 . Because the first conductive column 3 has a certain diameter, the heat dissipation is high, and the reliability is high and not easy to be damaged, so that the flip-chip radio frequency chip has high heat dissipation and reliability; at the same time, the radio frequency bare chip 1 is flip-chipped on the substrate 2 surface, can effectively reduce the volume of the radio frequency chip, which is conducive to the improvement of the integration degree of the radio frequency chip; since the bonding wire in the prior art is eliminated, in this application, the conductive circuit layer 21 of the substrate 2 will be provided for Conductive lines with preset matching inductance are provided to match the parasitic capacitance brought by the RF die 1 .

The specific structure of a flip-chip radio frequency chip provided by the present invention will be described in detail in the following embodiments of the invention.

Please refer to FIG. 6 and FIG. 7 , FIG. 6 is a schematic structural diagram of a specific flip-chip radio frequency chip according to an embodiment of the present invention; FIG. 7 is a schematic side view of the structure of FIG. 6 .

Different from the above embodiments of the invention, the embodiments of the present invention further specifically limit the structure of the flip-chip radio frequency chip on the basis of the above embodiments of the invention. The rest of the content has been described in detail in the above embodiments of the invention, and will not be repeated here.

Referring to FIG. 6 and FIG. 7 , in the embodiment of the present invention, the surface of the substrate 2 facing away from the RF die 1 has second signal pins, and the surface of the second signal pins is provided with second conductive posts 4.

The above-mentioned second signal pins located on the side surface of the substrate 2 facing away from the RF die 1 are the pins of the entire RF chip. The surface of the second signal pins is fixed with a second conductive column 4, and the second conductive column 4 is ready for use. During the process, the radio frequency chip and other external components are beneficial to the communication channel between the circuit board on which the radio frequency chip is installed. When installing the radio frequency chip provided by the embodiment of the present invention, the radio frequency chip will be flipped on the surface of the circuit board, and the radio frequency chip will be electrically connected to the second conductive column 4 through the second signal pin. It should be noted that the above-mentioned second signal pins generally do not have protruding pins, that is, the above-mentioned second signal pins are generally in the shape of sheets and are located on the side of the substrate 2 facing away from the RF die 1 . At this time, the electrical signal generated by the communication between the radio frequency chip and the circuit board will be transmitted through the second conductive column 4 .

Specifically, in the embodiment of the present invention, the above-mentioned second conductive column 4 is usually a tin column. The tin column has a certain degree of flexibility while having good electrical conductivity, and its shape can be slightly deformed, which is conducive to flipping the radio frequency chip. on the surface of the circuit board.

In the embodiment of the present invention, the metal layers in the substrate 2 are all provided with conductive lines for transmitting signals in the radio frequency die 1 . In the conventional substrate 2, the metal layer includes a conductive line layer 21 and a ground layer, wherein the conductive line layer 21 is provided with conductive lines for transmitting electrical signals generated by the RF die 1, and the ground layer is usually a whole metal layer. is usually not used to transmit the electrical signal generated by the RF die 1, but is defined as the ground, that is, GND. In the embodiment of the present invention, the metal layers in the substrate 2 are all provided with conductive lines for transmitting signals in the RF die 1, that is, the metal layers in the substrate 2 are all conductive circuit layers 21 instead of ground layers. In this case, no formation is provided in the substrate 2 . During use, the circuit board on which the radio frequency chip provided by the embodiment of the present invention is installed must be provided with a ground layer, and the substrate 2 of the radio frequency chip is not provided with a ground layer, which can effectively improve the performance of the ground layer after installation and the internal use of the above-mentioned substrate 2 The height between the conductive lines providing the preset matching inductance, that is, increasing the height between the preset matching inductance and the ground layer, thereby effectively increasing the Q value of the preset matching inductance, so that the above-mentioned conductive lines for providing the preset matching inductance The wire can provide high-quality inductance, enabling broadband and low-loss designs.

In the flip-chip radio frequency chip provided by the embodiment of the present invention, the metal layers in the substrate 2 are all provided with conductive lines for transmitting signals in the radio frequency bare chip 1, so that the substrate 2 is not provided with a ground layer, thereby improving the preset The height between the matching inductance and the ground layer can effectively increase the Q value of the preset matching inductance, so that the above-mentioned conductive line for providing the preset matching inductance can provide high-quality inductance, and realize a design of broadband and low loss.

The present invention also provides a radio frequency device, including a circuit board and the flip-chip radio frequency chip provided in any of the above embodiments of the invention, wherein the flip-chip radio frequency chip is communicatively connected to the circuit board. For the remaining structures of the radio frequency device, reference may be made to the prior art, which will not be repeated here.

Since the flip-chip radio frequency chip provided by the above embodiments of the present invention has high heat dissipation and reliability, the radio frequency device provided by the embodiments of the present invention also has high heat dissipation and reliability.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments may be referred to each other.

Finally, it should also be noted that in this document, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply these entities or that there is any such actual relationship or sequence between operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

A flip-chip radio frequency chip and a radio frequency device provided by the present invention have been described in detail above. The principles and implementations of the present invention are described herein by using specific examples, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (7)

1. a flip chip radio frequency chip, is characterized in that, comprises radio frequency bare chip and substrate; The radio frequency die is located on the surface of the substrate, and a surface of the radio frequency die facing the substrate is provided with a first signal pin, and the first signal pin is fixed to the substrate through a first conductive column and faces the substrate. A surface of one side of the radio frequency bare chip; a conductive line for providing a preset matching inductance is arranged in the conductive circuit layer of the substrate. 2 . The flip-chip radio frequency chip of claim 1 , wherein the first conductive pillars are copper pillars. 3 . 3 . The flip-chip radio frequency chip according to claim 2 , wherein the diameter of the cross section of the copper pillar is not greater than 1 mm. 4 . 4 . The flip-chip RF chip according to claim 1 , wherein a surface of the substrate facing away from the RF die has a second signal pin, and a surface of the second signal pin is provided with a second signal pin. 5 . Conductive post. 5 . The flip-chip radio frequency chip of claim 4 , wherein the second signal pins are tin pillars. 6 . 6 . The flip-chip radio frequency chip according to claim 1 , wherein the metal layers in the substrate are all provided with conductive lines for transmitting signals in the radio frequency die. 7 . 7. A radio frequency device, comprising a circuit board and the flip-chip radio frequency chip according to any one of claims 1 to 6, wherein the flip-chip radio frequency chip is communicatively connected to the circuit board.