KR100583239B1 - Transmitter/receiver module of communication - Google Patents

Abstract

The present invention relates to a communication transmitting / receiving module having a chip mounted thereon which can improve low thermal conductivity of a substrate and a mounted chip through flip chip technology using a low temperature co-fired ceramic (LTCC) substrate. A plurality of dielectric substrates; A plurality of cavities formed by locally opening the dielectric substrate of the upper partial layer; A chip mounted in the cavity in a flip chip manner, the chip being mounted to face an upper surface spaced apart from a bottom surface of the cavity; It is connected to the lower surface of the chip through a conductive adhesive, and provides a communication transmitting and receiving module comprising a conductive plate covering the top of the dielectric substrate.

Telecom Transceiver Modules, LTCC, MMIC, Flip Chip, Cavity

Description

Communication Transmit and Receive Module {TRANSMITTER / RECEIVER MODULE OF COMMUNICATION}             

1 is a cross-sectional view for explaining a communication transmission and reception module according to an embodiment of the present invention.

2 is a perspective view of the communication transmitting and receiving module shown in FIG.

3 is a perspective view of the communication transmitting and receiving module shown in FIG.

<Explanation of symbols for main parts of drawing>

11: conductive plate 12: ground plate

13 substrate layer 13a first substrate layer

13b: second substrate layer 131 to 138: LTCC substrate

14: cavity 15: chip

16: active element and / or passive element)

17, 18: circuit pattern 19a, 19b: via contact

20: bumper 21, 24, 27: conductive layer

22 conductive epoxy 23 transmission line

25: underfill material 26: pad

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication transmission and reception module, and particularly, to a millimeter wave in which a MMIC chip is mounted through a flip chip technology using a low temperature co-fired ceramic (LTCC). It relates to a communication transmission and reception module.

Advances in telecommunications and digital technology are driving the need for new materials, components, modules and substrates that are used in high frequency bands and have high data rates. In particular, in the mobile communication field, high frequency, high integration, and miniaturized components are required according to the trend of miniaturization, multi-band, and high customization of mobile communication devices. Accordingly, in chip manufacturing, chip miniaturization and integration are progressing, and in the package field, new packages and mounting methods that are light and short have been developed.

On the other hand, in recent years, in order to meet the demand for broadband wireless multimedia services, attention and technology development for a fixed frequency band of more than a millimeter wave (mm wave) band has been concentrated. Accordingly, much research has been made to develop parts and devices for millimeter waves. In implementing a millimeter wave communication transceiver module using these components and devices, a lot of researches have been conducted on a low loss transition technology and a package method for implementing a compact, lightweight and low cost module within a range that minimizes performance degradation.

As described above, in developing the millimeter wave communication transmission / reception module, important elements are miniaturization, low loss and low cost. One of the most difficult factors in the development of the millimeter wave communication transceiver module is a chip mounting method such as an MMIC chip. In general, wire bonding technology has been widely used as a chip mounting method, and when a chip is mounted using this technology, parasitic components are induced in microwave and millimeter wave communication transceiver modules. do. In order to prevent the occurrence of such parasitic components, an impedance matching circuit is essentially required in the communication transceiver module for microwave and millimeter wave.

Implementing the impedance matching circuit as described above requires a separate area, which adversely affects high integration. The proposed technique to compensate for this is flip chip technology. Such a flip chip technology can reduce not only the area of the package, but also the occurrence of parasitic components, etc., so that it is emerging as the most efficient method for chip mounting. However, the chip package technology using a conventional flip chip has severe distortion due to the change in the dielectric constant of the chip due to the low thermal conductivity of the substrate and the chip used for mounting the chip and the underfill material used to compensate for the chip. Induces characteristics.

 Therefore, the present invention has been proposed to solve the above problems of the prior art, and the following objects are proposed.

First, an object of the present invention is to provide a chip-mounted communication transmission / reception module that can improve low thermal conductivity of a substrate and a chip mounted through a flip chip technology using an LTCC substrate.

Secondly, another object of the present invention is to provide a chip-mounted communication transmission / reception module capable of minimizing a change in the dielectric constant of a chip due to an underfill material through a flip chip technology using an LTCC substrate.

According to an aspect of the present invention, there is provided a plurality of stacked dielectric substrates, a plurality of cavities formed by locally opening an upper portion of the dielectric substrate, and a flip chip method within the cavities. A communication chip including a chip mounted on the chip, the chip having a top surface facing away from a bottom surface of the cavity, and a conductive plate connected to a bottom surface of the chip through a conductive adhesive and covering the top dielectric substrate; Provides a transceiver module.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various other forms.

1 is a cross-sectional view for explaining a communication transmission and reception module according to an embodiment of the present invention, Figure 2 is a perspective view from the front, Figure 3 is a perspective view from the back. The same reference numerals among the reference numerals shown in FIGS. 1 to 3 are the same elements.

1 to 3, a communication transmitting and receiving module according to a preferred embodiment of the present invention is a multilayer board type module using an LTCC, the conductive plate 11 positioned at the top and the ground positioned at the bottom in a direction opposite to each other. Inserted between the plates 12, the plurality of LTCC substrates 131 to 138 include a substrate layer 13 having a laminated structure. Here, the LTCC substrates 131 to 138 are made of a dielectric material. Meanwhile, although the substrate layer 13 includes eight LTCC substrates 131 to 138 in FIG. 1, this is illustrated as an example for convenience of description, and the number of LTCC substrates constituting the substrate layer 13 is a circuit. It may be appropriately changed depending on the structure.

In the multilayered substrate layer 13 of the multilayer structure 13, there are a plurality of passive elements 16 in the LTCC substrate layer 13a (hereinafter, referred to as a 'first substrate layer') positioned below and arbitrarily divided therefrom. A plurality of vias and via pads 19a and 19b are disposed, and the LTCC substrate of the upper partial layer is disposed in the LTCC substrate layer 13b (hereinafter, referred to as a 'second substrate layer') positioned thereon. This local opening opens a plurality of cavities 14, while a plurality of circuit patterns 18, 19 are formed. Here, the passive elements are resistors, capacitors and inductors.

The cavity 14 has a multilayer structure which consists of a wide upper part and a lower part narrower than the upper part. In addition, the cavity 14 may be formed to have a different depth depending on the device to be mounted. For example, the depth of the cavity in which the chip 15 such as the MMIC chip is mounted is formed deeper than the depth of the cavity in which the active element 16 is mounted. This is because the height can be increased by the chip 15 because it is mounted in the cavity 14 through the flip chip technology. Therefore, in order to planarize the conductive plate 11 connected to the uppermost LTCC substrate, the depth of the cavity 14 is preferably changed in consideration of the height of the chip 15 and the active element 16 to be mounted. Here, the active elements 16 are diodes and transistors. In the bottom portion of the cavity 14, a conductive layer 24 connected to the ground plate 12 is formed through a plurality of via contacts 19b.

The chip 15 is placed on a bumper 20 disposed on top of the LTCC substrate 136 of the second substrate layer 13b whose top surface forms the cavity 14 through flip chip technology, The face (or ground plane) is connected with the conductive plate 11 via a conductive adhesive, such as epoxy 22. Through this structure, the high heat generated when the chip 15 is driven is discharged to the outside through the conductive epoxy 22 and the conductive plate 11. In addition, since the conductive plate 11 covers the lower surface of the chip 15, a reliable shielding effect can also be obtained. Therefore, a package can be constructed in a single process, compared to a separate process step for shielding in a package using a conventional wire bonding technology.

In addition, the chip 15 is mounted so that the top surface thereof is spaced apart from the bottom surface of the cavity 14. As a result, a single layer or a multilayer air layer is formed between the chip 15 and the bottom portion of the cavity 14. The air layer may prevent the underfill material 25 from flowing into the upper surface of the chip 15 due to a capillary phenomenon when the underfill material 25 is introduced, thereby minimizing the change in characteristics.

The conductive layer 21 is interposed between the bumper 20 and the LTCC substrate 136 to electrically connect the chip 15 and the circuit patterns 17 and 18. On the other hand, the circuit pattern 17 is a matching circuit, and is formed for low loss transitions between the chips 15, a transmission line (not shown), a plurality of via contacts and via pads such as strip lines, micro strip lines, and the like. It is connected to the chip 15 through). This configuration can reduce the size of the overall system package. The circuit pattern 18 is a compensation circuit according to an impedance change that may occur when the bumper 20 and the LTCC substrate 136 are connected. One end of the circuit pattern 18 is connected to a transmission line 23 to which an RF signal is input / output. The conductive layer 21 connected with the bumper 20 is connected. Here, the transmission line 23 is electrically separated from the conductive plate 11.

Meanwhile, the pads 26 disposed between the ground plates 12 function as pads for applying a bias voltage to the chip 15 and are electrically connected to the conductive layer 21 through the vias 19b. Thus, the bias voltage is supplied to the chip 15 and / or the active device (and / or the passive device) 16 through the via and via pad 19 shielded by the substrate layer 13, thereby affecting the overall circuit characteristics. Minimize the cost and increase the density of the entire circuit, which is advantageous for miniaturization and low cost. In addition, the pad 26 can be connected to an IF input / output pad having a relatively low frequency.

In addition, the pad 26 and the transmission line 16 function as input / output ports, and the pad 26 is connected to external components or elements such as a mother board through a ball, and the transmission line The furnace 16 may be connected with external components or elements through a ball or connector.

Hereinafter, a method of manufacturing a communication transceiving module according to a preferred embodiment of the present invention described above will be described.

1 to 3, a plurality of vias and via pads 19a and 19b, circuit patterns 18 and 19, and passive elements are formed, and a ground plate 12 is disposed below and a transmission line on one side thereof. The upper partial layer of the LTCC substrate layer 13 on which the furnace 23 is disposed is locally patterned to form a plurality of cavities 14.

Then, conductive layers 21 and 24 are formed in a portion of the cavity 14 where the bottom portion of the cavity in which the chip 15 is mounted and the chip 15 are connected through the bumper 20. At this time, the conductive layer 21 is electrically connected to the pad 26 via the via 19b via the conductive layer 27 connected to the via 19b, and the conductive layer 24 connects the via 19b. It is electrically connected to the ground plate 12 through.

Then, the chip 15 is mounted in the cavity 14 using the flip chip method. At this time, the top surface of the chip 15 is opposed to the bottom surface of the cavity 14 so that a single layer or a multilayer air layer is formed between the top surface of the chip 15 and the bottom surface of the cavity 14. do.

For example, in the flip chip method, the bumper 20 is adhered to the upper portion of the conductive layer 21, the chip 15 is seated thereon, and the underfill material 25 is interposed between the chip 15 and the conductive layer 21. Flows into the air layer of the cavity 14 formed by the chip 15. In this case, the bumper 20 may be first adhered to the upper surface of the chip 15 and then to the upper surface of the conductive layer 21.

Then, the active and passive elements 16 are mounted in the cavity in which the active and passive elements 16 are to be mounted. In this case, the mounting process of the active and passive elements 16 may be performed first before the mounting process of the chip 15. copper

Then, the conductive plate 11 is bonded to the upper surface of the LTCC substrate 138 and the lower surface of the chip 15 using the conductive epoxy 22. At this time, the conductive plate 11 is connected to the ground plate 12 through the via 19b.

Although the technical spirit of the present invention described above has been described in detail in the preferred embodiments, it should be noted that this is for the purpose of description and not of limitation. In addition, it will be understood by those skilled in the art that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the communication transmitting and receiving module of the present invention has the following effects.

First, a plurality of cavities are formed in a multilayered LTCC substrate layer, a chip such as an active element and an MMIC chip is mounted therein, and the bottom surface of the chip is connected to a conductive plate to improve the heat dissipation efficiency of the chip. Can be improved.

Second, the underfill material used in flip chip technology is prevented from entering the upper surface of the chip by the air layer of the cavity formed in the portion corresponding to the upper surface of the chip after the chip is mounted inside the cavity. The change in the dielectric constant of the chip due to the penetration of the material can be minimized.

Third, a plurality of vias are formed in the multilayered LTCC substrate layer, and vias are supplied to the chip and / or the active and passive elements mounted in the cavity, respectively, to supply overall external circuit characteristics. Minimize the impact and increase the density of the entire circuit, which is advantageous for miniaturization and low cost of the communication transceiver module.

Fourth, the size of the entire system package can be reduced by constructing a transmission pattern (or conductive layer), a plurality of vias and via pads, which are formed for the impedance matching between the chips or between the chip and the dielectric substrate on which the chips are mounted. have.

Claims (8)

A plurality of stacked dielectric substrates; A plurality of cavities formed by locally opening the dielectric substrate of the upper partial layer; A chip mounted in the cavity in a flip chip manner, the chip being mounted to face an upper surface spaced apart from a bottom surface of the cavity; And A conductive plate connected to the lower surface of the chip through a conductive adhesive and covering the dielectric substrate on the top; Communication transmitting and receiving module comprising a. The method of claim 1, A ground plate covering a rear surface of the lowermost dielectric substrate; And And a pad formed on a rear surface of the lowermost dielectric substrate separated from the ground plate. The method of claim 1, And a circuit pattern formed between the chips for mutual impedance matching. The method of claim 1, And a circuit pattern formed to compensate for impedance changes occurring between the chip and the dielectric substrate connected to the bumper connected to the chip. The method according to claim 3 or 4, And the circuit pattern is connected to the chip through a via contact and a transmission line connected to the via contact. The method of claim 1, And a transmission line arranged to be electrically separated from the conductive plate to transmit an RF signal to the chip on one side of an uppermost dielectric substrate. The method of claim 1, And a conductive layer connected to a via contact connected to a ground plate covering a lowermost dielectric substrate at a bottom portion of the cavity. The method of claim 1, The cavity is a communication transmitting and receiving module is formed so that the upper portion is wider than the lower portion, the chip is mounted so that the air layer is formed on the lower side.

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