KR101393771B1 - Front end module and method for fabricating the same - Google Patents

Abstract

Embodiments relate to a front end module (FEM) and a manufacturing method thereof. The front-end module includes a resonator circuit formed over the substrate upper surface and the substrate inner surface, and includes a filter for filtering the corresponding band signal, and a switching unit connected to the filter and mounted on the upper surface of the substrate. This minimizes the number and size of the components of the front-end module, thereby securing the degree of freedom in designing the low-pass filter and the degree of freedom in component placement on the multilayered board. The insertion loss of the filter The damping characteristic can be improved.

Front-end module, LTCC

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a front-

1 is a block diagram illustrating a communication terminal according to an embodiment.

2 is a circuit diagram of a first low-pass filter part of the front-end module according to the embodiment.

3 is a plan view showing a substrate on which a front end module according to an embodiment is mounted.

4 is a cross-sectional view taken along the line I-I 'of FIG. 3 to show a portion of the first low-pass filter.

5 is a circuit diagram of a first low-pass filter part of a front-end module according to another embodiment.

Embodiments relate to a front end module (FEM) and a manufacturing method thereof.

As the mobile communication terminal develops with high performance and miniaturization tendency, the parts built in the terminal are being developed by integration, miniaturization and light weight.

Also, a multi-band front-end module in which a terminal can cover other bands using one antenna or integrate components capable of transmitting or receiving signals in a plurality of frequency bands into one module Is being developed.

The embodiment provides a front-end module.

An embodiment provides a method of manufacturing a front-end module.

A front end module according to an embodiment includes a resonance circuit formed over an upper surface of a substrate and a substrate, and includes a filter for filtering a corresponding band signal, and a switching unit connected to the filter and mounted on the upper surface of the substrate.

A method of manufacturing a front-end module according to an embodiment of the present invention includes the steps of preparing a ceramic substrate having at least one inductor and at least one capacitor mounted thereon and baking at low temperature, a step of forming a part of at least one of the inductor and the capacitor Forming a metal pattern in the via hole and the via hole to be exposed, mounting an additional inductor on the upper surface of the ceramic substrate connected to the metal pattern, and a switch chip connected to the filter on the upper surface of the ceramic substrate, And mounting the semiconductor device.

Hereinafter, a front end module will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a communication terminal according to an embodiment.

1, the front-end module 100 is a module for transmitting and receiving RF signals of a frequency band of two or more bands, and includes a switching unit 103, a decoder unit 105, first through fourth matching units 111, 112, 113 and 114, first through fourth filter units 131, 132, 133 and 134, and first and second low-pass filter units 121 and 122.

The front-end module 100 transmits an RF signal received from the antenna 101 to a receiving terminal Rx connected to a corresponding receiving path and outputs an RF signal input from the transmitting terminal Tx to the antenna 111. [

The switching unit 103 is implemented as a semiconductor chip having a structure of at least one SPnT (Single Pole n Throw, where n is a natural number) for selectively conducting only a desired path among transmission / reception paths of multiple bands .

The switching unit 103 selects one of the low frequency transmission path b and the high frequency transmission path c and the low frequency reception path a and the high frequency reception path d.

Here, the low-frequency reception path (a) is a line commonly connected to the receiving ends of the GSM Rx and the EGSM Rx, which are the low frequency bands, and the high-frequency receiving path (d) connects the receiving ends of the DCS Rx and PCS Rx, It is a track.

For example, when the switching unit 103 is a quad band, six transmission / reception paths can be implemented by four paths.

The decoder 105 receives the two control voltages Vctrl 1 and Vctrl 2 and the power supply Vcc from the voltage supply unit 107 in the case of a quad band and controls the transmission and reception path of the switching unit 103 can do.

First to fourth matching units 111, 112, 113 and 114 and first to fourth filter units 131, 132, 133 and 134 are formed as a receiving filter at the rear end of the switching unit 103, The first and second low-pass filter portions 121 and 122 are formed as filters.

The first low-pass filter unit 121 is connected to the GSM / EGSM transmitter and removes high-frequency noise of a transmission signal in the GSM / EGSM band, and outputs the high-frequency noise to the switching unit 103.

The second low-pass filter 122 is connected to the DCS / PCS transmitter and removes high-frequency noise of a transmission signal in the DCS / PCS band and outputs the high-frequency noise to the switching unit 103.

Each of the first to fourth filter units 131, 132, 133, and 134 may include at least one SAW filter.

The first filter unit 131 filters the GSM band from the RF signal received from the switching unit 103 through the low-frequency receiving path (a) and outputs the filtered signal.

The second filter unit 132 filters the EGSM band from the RF signal received through the low frequency receiving path (a) from the switching unit 103 and outputs the filtered signal.

The low frequency receiving path (a) connected to one path of the switching unit 103 is branched and connected to the input ends of the first filter unit 131 and the second filter unit 132, respectively.

The third filter unit 133 filters the DCS band from the RF signal received through the high frequency receiving path (d) from the switching unit 103 and outputs the DCS band.

The fourth filter unit 134 filters the PCS band from the RF signal received through the high frequency receiving path (d) from the switching unit 103 and outputs the filtered signal.

The high frequency receiving path d connected to one path of the switching unit 103 is branched and connected to the input terminals of the third filter unit 133 and the fourth filter unit 134, respectively.

A first matching unit 111 is connected in series to an input terminal of the first filter unit 131. The first matching unit 111 performs impedance matching on a received RF signal and outputs the impedance matching signal to the first filter unit 131 Output.

A second matching unit 112 is connected in series to an input terminal of the second filter unit 132. The RF signal received by the second matching unit 112 is impedance matched to the second filter unit 132, Output.

A third matching unit 113 is connected in series to an input terminal of the third filter unit 133. The RF signal received by the third matching unit 113 is impedance matched to the third filter unit 133, Output.

A fourth matching unit 114 is connected in series to an input terminal of the fourth filter unit 134. The RF signal received by the fourth matching unit 114 is impedance matched to the fourth filter unit 134 Output.

The first to fourth matching units 111, 112, 113 and 114 are implemented by a combination of at least one inductor and / or at least one capacitor element.

For example, the first to fourth matching units 111, 112, 113, and 114 may be a combination of a series capacitor and a parallel inductor, or may be a combination of parallel inductors.

The first to fourth matching units 111, 112, 113, and 114 may block adjacent frequency bands input to the respective filter units and perform impedance matching with a desired frequency band.

2 is a circuit diagram of a first low-pass filter part of the front-end module according to the embodiment.

2, the first low pass filter 121 includes a first inductor 151, a second inductor 152, a third inductor 153, a first capacitor 154, a second capacitor 155, And a third capacitor 156, as shown in FIG.

The first inductor 151 and the first capacitor 154 are connected in parallel to form a parallel resonant circuit and are connected to the input and output terminals of the first low pass filter 121.

The output terminal is connected to the switching unit 103 and the input terminal is connected to a transmitting terminal (GSM / EGSM Tx).

The second inductor 152 and the second capacitor 155 constitute a series resonance circuit and are connected in parallel at one end of the parallel resonance circuit.

The third inductor 153 and the third capacitor 156 constitute a series resonance circuit and are connected in parallel at the other end of the parallel resonance circuit.

The front-end module having the first low-pass filter part 121 formed as described above is formed on the substrate.

For example, the substrate may be a multilayer substrate made using a low temperature fired ceramic (LTCC) laminating process. The substrate may be made of a conductive metal having excellent conductivity such as gold or silver and capable of being fired in an oxidizing atmosphere, and various passive elements such as a resistor, a capacitor, and an inductor may be formed in the substrate.

At least one of the first to third inductors 151, 152 and 153 and the first to third capacitors 154, 155 and 156 may be mounted on the upper surface of the substrate.

For example, the first and second inductors 151 and 152 and the first to third capacitors (not shown) except for the third inductor 153, for example, 154, 155, 156 may be formed in the substrate.

The elements mounted on the substrate and the elements formed in the substrate inner region may be electrically connected to each other by the via holes and the via metal filled in the via holes.

Referring to FIG. 2, the "A" portion of the first low-pass filter 121 is mounted on the upper surface of the substrate as a third inductor 153. In other words, the first low-pass filter portion 121 is formed over the substrate upper surface and the substrate internal region.

The inductance of the third inductor 153 mounted on the substrate may vary according to the design.

The inductance and the capacitance of the preformed inductor and the capacitor in the substrate are fixed at a constant value in manufacturing the substrate.

Although the first and second inductors 151 and 152 and the first to third capacitors 154 and 155 and 156 formed in the substrate inner region have a fixed value, the third inductor 153 and the third inductor 153, The insertion loss and the attenuation characteristic of the desired low-pass filter can be obtained. Further, since the third inductor 153 is mounted on the upper surface of the substrate, it is possible to secure a sufficient area for device formation at the time of designing the substrate, so that a sufficient area for designing an inductor having a large inner diameter can be obtained And it is easy to implement an inductor having a high quality (high Q), thereby realizing a low-pass filter having a better insertion loss.

Among the elements constituting the first low pass filter 121, the element mounted on the upper surface of the substrate may be a capacitor or an inductor. The device mounted on the upper surface of the substrate may be a device in which a capacitor and an inductor are connected in series or in parallel. The arrangement of such devices can be various embodiments in consideration of the characteristics of the low-pass filter.

For example, the third inductor 153 may be mounted on the upper surface of the substrate, and one side of the third inductor 153 may be connected to the ground.

In addition, the embodiment can be designed with a single-stage low-pass filter having the same or higher performance as that of the two-stage low-pass filter, and the inductor and / or the capacitor of the low- The insertion loss and the attenuation characteristics can be improved, and design and tuning are free.

Although the embodiment is described as the first low-pass filter unit 121, the second low-pass filter unit 122 may have the structure of the above-described embodiment.

FIG. 3 is a plan view showing a substrate on which a front end module according to the embodiment is mounted, and FIG. 4 is a cross-sectional view showing a part of the first low-pass filter portion taken along the line I-I 'of FIG.

As shown in FIGS. 3 and 4, a switching unit 103, a first matching unit 111, a second matching unit 112, a first filter unit 131, 2 filter portion 132 and the third inductor 153 of the first low-pass filter portion 121 are mounted.

The substrate 140 may be a multi-layer substrate made of LTCC.

Although not shown, the third matching unit, the fourth matching unit, the third filter unit, and the fourth filter unit may be further mounted on the upper surface of the substrate 140.

At least one inductor and / or capacitor of the second low-pass filter portion may be mounted on the upper surface of the substrate 140.

The elements of the first low-pass filter 121 and the elements of the second low-pass filter 122 are mounted in the substrate 140. For example, the elements of the first low pass filter 121 may include a first inductor 151 and a second inductor 152, and first through third capacitors 154, 155, and 156 .

The elements constituting the surface or the inner region of the substrate 140 are electrically connected to each other and may be arranged in consideration of electrical signal characteristics.

3 and 4, the first low-pass filter 121 includes a third inductor 153 formed on the upper surface of the substrate 140, a third capacitor (not shown) formed in the substrate 140, 156 are vertically connected to the surface of the substrate 140 by the metal pattern 171 formed in the via hole.

A manufacturing method of the front end module according to the embodiment will be briefly described as follows.

At least one inductor and at least one capacitor are mounted inside to prepare a ceramic substrate which is baked at low temperature. A via hole exposing a part of at least one of the inductor and the capacitor and a metal pattern in the via hole are formed in the ceramic substrate. And an additional inductor is mounted on the upper surface of the ceramic substrate connected to the metal pattern. And a switch chip connected to the filter is mounted on the upper surface of the ceramic substrate.

Whereby said at least one inductor, said at least one capacitor and said additional inductor form resonant circuits. The resonant circuits may implement a low-pass filter.

5 is a circuit diagram of a first low-pass filter part of a front-end module according to another embodiment.

5, the first low-pass filter unit 221 includes a first inductor 251, a second inductor 252, and first to fifth capacitors 253, 254, 255, 256, and 257 .

The first inductor 251 and the first capacitor 253 are connected in parallel to form a resonant circuit and the second inductor 252 and the second capacitor 254 are connected in parallel with each other to form another resonant circuit .

The resonant circuits are connected in series to form a two-stage filter.

The output terminal of the first low-pass filter unit 221 is connected to the switching unit 103 and the input terminal is connected to a transmitter (GSM / EGSM Tx).

The third capacitor 255 is connected in parallel between the resonant circuits and the output terminal, and the third capacitor 255 is grounded.

The fourth capacitor 256 is connected in parallel between the resonant circuits and the fourth capacitor 256 is grounded.

The fifth capacitor 257 is connected in parallel between the resonant circuits and the input terminal, and the fifth capacitor 257 is grounded.

The front-end module having the first low-pass filter part 221 formed as described above is formed on the substrate.

The substrate may be a multi-layer substrate made of LTCC.

At least one element of the first and second inductors 251 and 252 and the first to fifth capacitors 253, 254, 255 and 256 may be mounted on the upper surface of the substrate. An element mounted on the upper surface of the substrate may be electrically connected to elements formed in an inner region of the substrate through a via hole to implement the first low-pass filter.

5, the third capacitor 255 is mounted on the upper surface of the substrate, and the third capacitor 255 is mounted on the same surface as the switching unit 103.

According to the embodiment, since the capacitance of the third capacitor 255 can be set according to the design and arrangement of the elements, the design and tuning of the low-pass filter are advantageous.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications not illustrated in the drawings are possible. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

By minimizing the number and size of the components of the front-end module, the degree of freedom in designing the low-pass filter and the degree of freedom in component placement can be ensured on a multilayered substrate.

 The embodiment can realize a high-quality inductor on a multilayer substrate, thereby improving the characteristics of the low-pass filter and improving the insertion loss and damping characteristics in the low-pass filter.

The product reliability in the terminal to which the front-end module according to the embodiment is applied can be improved.

Claims (13)

A filter for filtering the input signal; And And a switching unit connected to the filter and mounted on an upper surface of the substrate, The filter includes: And a parallel resonant circuit connected between the switching unit and the input terminal, the parallel resonant circuit including first and second serial resonant circuits, The other end of the first series resonant circuit is connected to the switching unit, The other end of the second series resonant circuit is connected to the input end, Wherein the first series resonance circuit and the parallel resonance circuit are constituted by an inductor and a capacitor formed in an inner region of the substrate, Wherein the second series resonant circuit comprises a capacitor formed in an inner region of the substrate and an inductor mounted on an upper surface of the substrate. delete The method according to claim 1, Wherein the substrate is a multilayer substrate made of a low temperature co-fired ceramic. The method according to claim 1, Wherein the resonant circuit includes a via hole for connecting the substrate inside area and the substrate upper surface, and a metal pattern filled in the via hole. delete delete Preparing a ceramic substrate having at least one inductor and at least one capacitor mounted therein so as to be low temperature baked; Forming a via hole for exposing a part of at least one of the inductor and the capacitor on the ceramic substrate and a metal pattern in the via hole; Mounting at least one of an inductor and a capacitor on a top surface of the ceramic substrate connected to the metal pattern; And And mounting a switch chip connected to a low-pass filter for filtering a signal at an input terminal on the upper surface of the ceramic substrate, Wherein the inductor and the capacitor constitute the low-pass filter. A low-pass filter composed of at least one inductor and a capacitor for filtering a signal at an input terminal; And And a switching unit connected to the low-pass filter and mounted on a top surface of the substrate, Wherein at least one of the inductor and the capacitor is mounted on an upper surface of the substrate. 9. The method of claim 8, The low- And first and second parallel resonant circuits and first to third capacitors, Wherein the first and second parallel resonant circuits are connected between the switching unit and the input terminal. 10. The method of claim 9, The first capacitor is connected to the switching unit, The second capacitor is connected between the first and second parallel resonant circuits, And the third capacitor is connected to the input terminal. 11. The method of claim 10, Wherein the first capacitor is mounted on an upper surface of the substrate. 9. The method of claim 8, Wherein the substrate is a multilayer substrate made of a low temperature co-fired ceramic. The method of claim 8, wherein Wherein the low-pass filter includes a via-hole for connecting an inner region of the substrate with an upper surface of the substrate, and a metal pattern filled in the via-hole.

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