JP2005217579A - High frequency power amplification module and mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency power amplification module with a high efficiency without causing a transmission loss of an output signal pattern and a bias pattern or the like while attaining downsizing and low profile. <P>SOLUTION: The high frequency power amplification module includes an input signal pattern 3 for supplying a signal to a power amplifier element 2 mounted on the front side of a dielectric board 1, the output signal pattern 4 for extracting the signal from the power amplifier element 2, and the bias pattern 5 for supplying power to the power amplifier element 2, and the input signal pattern 3, the output signal pattern 4, and the bias pattern 5 are formed on the surface or the inside of the dielectric board 1, and the conductor thickness of at least one of the output signal pattern 4 and the bias pattern 5 is thicker than that of the input signal pattern 3. Particularly, a relation of t2≥1.5×t1 or t3≥1.5×t1 holds, wherein t1 is the conductor thickness of the input signal pattern, t2 is the conductor thickness of the output signal pattern, and t3 is the conductor thickness of the bias pattern. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a small-sized, high-performance, low-cost, high-frequency power amplification module that is used in electronic devices and devices such as portable information terminals, wireless LANs, and WLL (Wireless Local Loop).

  Conventionally, a high-frequency power amplification module used for wireless communication or the like has various circuits provided by a conductor layer on a dielectric substrate made of ceramics due to excellent physical properties of ceramics, such as dielectric properties and heat dissipation. .

  Conventional high-frequency power amplification modules produce a green sheet by a doctor blade method or the like using glass powder or ceramic powder as a dielectric layer, and after forming a through hole in this sheet with an NC punch or a mold, A conductive paste is filled, and a wiring pattern is printed on the surface of the green sheet, and then a plurality of these sheets are laminated and fired (see Patent Document 1). As a result, as shown in FIG. 6, the power amplifying element 2 is mounted on the surface of the dielectric substrate 21, and the input signal pattern 23, the output signal pattern 24, and the bias printed on the surface of the dielectric substrate 21 are biased. The pattern 25 is wire-bonded. In each pattern 23, 23, 25, electrodes are formed with a dielectric layer interposed therebetween, and capacitors 26, 27, 28 are formed. Further, a plurality of via conductors 29 are formed immediately below the power amplification element 2 and connected to the ground electrode 30.

In recent years, with the spread of mobile communication devices such as mobile phones, there has been a strong demand for miniaturization and low profile of high frequency power amplification modules. Along with this, the circuit density has been increased, the thickness per dielectric layer has been reduced, the inner capacitance has been reduced, and the product height has been reduced to meet the market demands. .
JP 2002-359321 A

  However, as the thickness per dielectric layer is reduced, it is necessary to reduce the thickness of the inner conductor pattern. For example, when the thickness of the dielectric layer is 50 μm, if the conductor thickness is 20 μm or more, the step between the conductor layer and the dielectric layer becomes large. As a result, delamination occurs at the step portion between the conductor layer, In order to reduce the reliability as a circuit board, the conductor thickness needs to be 10 μm or less.

  However, when the thickness of the conductor layer is reduced, for example, in a high frequency power amplifier module used in a CDMA mobile phone, a current of several hundred mA is passed through the bias pattern, and a high frequency of about 1 W is applied through the output signal pattern. Although it is necessary to flow electric power, when the conductor thickness is reduced, the resistance values of these conductor layers are increased, causing a transmission loss, resulting in a decrease in efficiency.

  Accordingly, it is an object of the present invention to provide a high-efficiency high-frequency power amplification module that does not cause a transmission loss such as an output signal pattern or a bias pattern, while achieving a reduction in size and height.

  The high frequency amplifier circuit module of the present invention includes a dielectric substrate, a power amplifying element mounted on the surface of the dielectric substrate, an input signal pattern for supplying a signal to the power amplifying element, and a signal from the power amplifying element. An output signal pattern to be extracted and a bias pattern for supplying power to the power amplifying element, and the input signal pattern, the output signal pattern, and the bias pattern are formed on the surface or inside of the dielectric substrate. The amplification module is characterized in that a conductor thickness of at least one of the output signal pattern and the bias pattern is thicker than the input signal pattern. According to the present invention, such a structure can realize a reduction in the height and size of the module while maintaining the conductor thickness of the wiring that affects the efficiency.

  In the high-frequency power amplification module, when the conductor thickness t1 of the input signal pattern, the conductor thickness t2 of the output signal pattern, and the conductor thickness t3 of the bias pattern, t2 ≧ 1.5 × t1 or t3 ≧ 1.5 × By maintaining the relationship of t1, efficiency can be maintained even when the module is reduced in height and size.

  In the high-frequency power amplification module, at least one of the conductor thickness t2 of the output signal pattern and the conductor thickness t3 of the bias pattern is set to 20 μm or more, so that the module is reduced in height and size without deteriorating the efficiency. Can be realized.

  The conductor layer of at least one of the output signal pattern and the bias pattern is formed of a dielectric layer and a composite layer in which a conductor layer having substantially the same thickness as the dielectric layer is embedded through the dielectric layer. As a result, even if the thickness of the conductor layer is increased, a step difference from the dielectric layer does not occur, so that there is no reduction in reliability due to delamination or the like. In addition, the thickness of the conductor layer can be arbitrarily adjusted in accordance with the number of laminated composite layers.

  In particular, the entire module is composed of a dielectric layer and a laminate composed of a composite layer in which a conductor layer having substantially the same thickness as the dielectric layer is embedded through the dielectric layer. It is not necessary to perform steps such as forming a through hole and filling a through hole with a conductor paste in order to form a via conductor in the method, and the reliability can be further improved.

  Note that, by setting the thickness of the composite layer to 50 μm or less, the high-frequency module can be reduced in height and size.

  In addition, the composite layer includes, for example, (a) a step of forming a predetermined light-impermeable conductive pattern layer on a surface of a light-transmissive carrier film by using a conductive paste containing at least a metal powder and an organic binder. (B) A photocuring slurry containing at least a photocurable monomer, a photopolymerization initiator, and a dielectric material on the carrier film on which the conductor pattern layer is formed, has a thickness equal to or greater than the thickness of the conductor pattern layer. (C) from the back surface of the carrier film, light is irradiated from the back surface of the carrier film to photocure the photocurable dielectric layer in a region other than the conductor pattern layer formation, A step of applying a developing solution to solubilize and remove the non-photocured portion including the conductor pattern layer surface of the photocured dielectric layer to form a composite layer; and (d) a step of firing the composite layer. When It can be through in formation.

  In the high-frequency module of the present invention, the high-frequency power amplification module is provided with high functionality by including at least one of a diplexer, an antenna duplexer, a directional coupler, an isolator, a high-frequency switch, and a bandpass filter. Can do.

  By mounting the high-frequency module, it is possible to reduce the size and height of the mobile terminal device and improve the reliability.

  According to the present invention, in reducing the size and height of a high-frequency power amplification module, even if the thickness of the dielectric layer is reduced, the thickness of the output signal pattern and bias pattern that greatly affects the efficiency is increased. Accordingly, it is possible to provide a high-frequency power amplification module that has a long battery life and is suitable for electronic devices and electronic devices such as small and thin portable information terminals.

  FIG. 1A is a schematic perspective view, FIG. 1B is a schematic cross-sectional view of A-A ′, and FIG. 1C is a schematic cross-sectional view of B-B ′. FIG. 2 is a circuit diagram showing an example of a circuit formed by the high-frequency power amplification module of the present invention.

  In the figure, 1 is a dielectric substrate, 2 is a power amplification element, 3 is an input signal pattern, 4 is an output signal pattern, 5 is a bias pattern, 6 to 8 are capacitances, 9 is a heat dissipation conductor, and 10 is a ground pattern. . In FIG. 2, 11 is an input signal terminal, 12 is a power supply terminal, and 13 is an output signal terminal.

  According to the circuit of FIG. 2, the signal input from the input signal terminal 11 is input to the power amplifying element 2 through the capacitance 6 and the input signal pattern 3 and is amplified by the power amplifying element 2. The amplified signal is output to the output signal terminal 13 via the output signal pattern 4 and the capacitances 7 and 8. DC power is supplied to the power amplifying element 2 from the power supply terminal 12 via the bias pattern 5.

  According to FIG. 1, an input signal pattern 3, an output signal pattern 4, and a bias pattern 5 are formed on the surface of the dielectric substrate 1. The power amplifying element 2 is mounted on the substrate surface and connected to the input signal pattern 3, the output signal pattern 4, and the bias pattern 5 by bonding wires or solder. Further, in order to form capacitances 6, 7, and 8 inside the dielectric substrate 1, the input signal pattern 3, the output signal pattern 4, and the bias pattern 5 are respectively interposed through the dielectric layers 3a, 4a, and 5a. Thus, counter electrode patterns 3b, 4b and 5b are formed. The counter electrode patterns 3b, 4b, and 5b are connected to an input signal terminal 11, an output signal terminal 13, and a power supply terminal 12 formed on the back surface of the dielectric substrate 1, respectively. Further, a heat dissipating conductor 9 is buried immediately below the portion where the power amplifying element 2 is mounted, and heat generated during the amplification operation of the power amplifying element 2 passes through the heat dissipating conductor 9 and the GND pattern 10. Released outside the system.

  According to the present invention, in the above-described high frequency module, the conductor thickness of at least one of the output signal pattern 4 and the bias pattern 5 is formed thicker than the input signal pattern 3. Thus, by forming the conductor thickness of at least one of the output signal pattern 4 and the bias pattern 5 to be thicker than that of the input signal pattern 3, it is possible to avoid deterioration in efficiency due to the conductor thickness being reduced.

  For example, if the thickness t1 of the power amplification input signal pattern used in the CDMA system which is a 800 MHz band mobile phone system is 10 μm, the output signal pattern thickness t2 and the bias pattern thickness t3 are t2 ≧ 1.5. It is desirable that xt1 or t3 ≧ 1.5 × t1, particularly t2 ≧ 2 × t1 or t3 ≧ 2 × t1. Thereby, a decrease in efficiency due to the conductor resistance value can be avoided.

  For example, assuming that the minimum distance between conductors is 50 μm in order to reduce the area of the built-in capacitances 6, 7, and 8, the thicknesses t1, t2, and t3 of the respective patterns when manufactured based on the conventional green sheet method are used. Must be 10 μm or less, resulting in a reduction in efficiency. On the other hand, according to the present invention, in particular, by setting at least one of the conductor thickness t2 of the output signal pattern 4 and the conductor thickness t3 of the bias pattern 5 to 20 μm or more, 30 μm or more, and further 40 μm or more, Furthermore, the efficiency can be increased.

  On the other hand, when the thickness of the dielectric layer constituting the dielectric substrate 1 is set to 50 μm or less, particularly 40 μm or less, the module can be reduced in height and multifunctionalized.

  When a conductor pattern having a thickness of 20 μm or more is formed on such a thin dielectric layer, a step due to a difference in thickness between the two becomes large, and problems such as delamination tend to occur.

  Therefore, according to the present invention, at least one conductor layer of the output signal pattern 4 and the bias pattern 5 includes a dielectric layer, and a conductor layer having substantially the same thickness as the dielectric layer penetrates the dielectric layer. Formed by embedded composite layers.

  Such a composite layer can be produced, for example, by the following method. FIG. 3 shows a process chart for manufacturing the composite layer. According to FIG. 3, (a) a conductive pattern layer 101 having a predetermined pattern of light non-transmission is formed on a surface of a light transmissive carrier film 100 with a conductive paste, and (b) a photocuring slurry is formed thereon. The photo-curing ceramic layer 102 is formed by coating to a thickness greater than the thickness of the conductor pattern layer 101. Next, (c) light is irradiated from the back surface of the carrier film 100 to photocure the photocurable ceramic layer 102 in a region other than the formation of the conductor pattern layer 101, and (d) this is developed and developed. Thus, a composite layer composed of the photocurable ceramic layer 12 and the conductor pattern layer 11 is produced. In addition, (e) The carrier film 100 can be removed suitably.

  In the formation of the composite layer, the photocurable slurry used is desirably a ceramic powder, a photocurable monomer, a photopolymerization initiator, an organic binder, and a plasticizer mixed in an organic solvent, Prepare by kneading with a ball mill.

  As the photocurable monomer, it is desirable that the monomer is excellent in thermal decomposability in order to cope with a low-temperature and short-time baking process. In addition, the photo-curable monomer needs to be photopolymerized by exposure after application and drying of the slip material, and can form free radicals and chain-growth addition polymerization, and has a secondary or tertiary carbon. Preferred examples include alkyl acrylates such as butyl acrylate having at least one polymerizable ethylene group, and alkyl methacrylates corresponding thereto. In addition, polyethylene glycol diacrylates such as tetraethylene glycol diacrylate and methacrylates corresponding thereto are also effective. Examples of the photoinitiating material include benzophenones and acyloin ester compounds.

  In addition, the organic binder is desired to have good thermal decomposability like the photo-curable monomer, and at the same time, it determines the viscosity of the slip, so it is necessary to consider the wettability with the solid content. is there. According to the present invention, an ethylenically unsaturated compound having a carboxyl group and an alcoholic hydroxyl group such as an acrylic acid or methacrylic acid polymer is preferred.

  Examples of the organic solvent include at least one selected from the group consisting of ethyl carbitol acetate, butyl cellosolve, and 3 methoxybutyl acetate.

  The content of each component is 5 to 20 parts by mass of a photocurable monomer and a photopolymerization initiator, 10 to 40 parts by mass of an organic binder, 1 to 5 parts by mass of a plasticizer, and an organic solvent per 100 parts by mass of the ceramic powder. A ratio of 50 to 100 parts by mass is appropriate.

  Further, the conductive paste for forming the conductive pattern layer 101 is made of ethyl cellulose, acrylic resin with respect to an inorganic component obtained by adding a ceramic material to the powder of the conductive material having an average particle size of about 1 to 3 μm as necessary. Add an organic binder such as dibutyl phthalate, α-terpineol, butyl carbitol, and mix with a suitable solvent such as 2,2,4-trimethyl-3,3-pentadiol monoisobutyrate. It is prepared by homogeneously kneading.

  According to the composite layer, the thickness of the dielectric layer 102 and the conductor layer 101 forming the composite layer can be determined by the thickness of the conductor layer 101 formed first, the thickness of the dielectric layer 102 is thin, and the conductor The layer 101 can be formed thick.

  Further, when the thicknesses of the output signal pattern 4 and the bias pattern 5 are increased, the output signal pattern 4 and the bias pattern 5 can be thickened by stacking the required number of the composite layers until a predetermined thickness is reached. .

  For example, in FIG. 1, the input signal pattern 3 is formed of one composite layer, whereas the output signal pattern 4 is formed by stacking three composite layers, and the bias pattern 5 is combined. It is formed by laminating two layers.

  According to the present invention, as shown in FIG. 1, it is most desirable that the entire high-frequency amplifier circuit module is formed of the composite layer stack. In that case, in the composite layer in which the dielectric layer and the conductor layer are integrated, the position of the conductor layer is appropriately changed, and after laminating them, the laminate is fired to obtain a planar circuit as shown in FIG. A high-frequency power amplification module in which a dielectric substrate having a three-dimensional circuit is made of ceramics can be formed by a vertical circuit.

  For example, in a conventional high-frequency module, as shown in FIG. 5, instead of a heat radiating via in which a plurality of via conductors are formed, a heat radiating body can be provided with a heat radiating region formed entirely by a conductor layer. Compared with the heat dissipation efficiency can be increased. In addition, since the dielectric layers and electrodes forming the capacitors 6, 7, and 8 can be thinned, the capacitors 6, 7, and 8 can be downsized.

  The surface of the output signal pattern 4, the bias pattern 5 and the input signal pattern 3 formed on the surface of the dielectric substrate 1 has a plated layer of nickel, gold or the like in order to improve wettability with solder. Is formed with a thickness of 1 to 3 μm.

  Further, if necessary, the surface treatment further includes input signal pattern 3, output signal pattern 4, bias pattern 5 printing / baking a thick film resistance film or thick film protective film on the substrate surface, plating treatment, and further including an IC chip. Electronic parts may be mounted. Further, if necessary, the input / output signal patterns 3 and 4, the bias pattern 5 and the power amplifying element 2 are connected by wire bonding. Furthermore, various circuits formed on the surface of the dielectric substrate 1 and electronic components mounted and mounted are sealed with a resin or the like, or a lid is attached to complete a high frequency power amplification module.

In the above-described high-frequency power amplification module according to the present invention, the dielectric substrate 1 includes: (1) a ceramic material having a firing temperature of 1100 ° C. or higher mainly composed of Al ₂ O ₃ , AlN, Si ₃ N ₄ , and SiC; A ceramic material fired at 1100 ° C. or lower, particularly 1050 ° C. or lower, comprising a mixture of metal oxides containing at least SiO ₂ and an alkaline earth metal oxide such as BaO, CaO, SrO, MgO, etc. (3) Glass powder Alternatively, at least one selected from the group of low-temperature sinterable ceramic materials which are fired at 1100 ° C. or less, particularly 1050 ° C. or less, comprising a mixture of glass powder and ceramic filler powder is selected.

As the mixture of (2) and the glass composition of (3) used, SiO ₂ —BaO—Al ₂ O ₃ system, SiO ₂ —B ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ systems, SiO ₂ —Al ₂ O ₃ —alkali metal oxide systems, and compositions in which alkali metal oxides, ZnO, PbO, Pb, ZrO ₂ , TiO _2, etc. are blended with these systems. Examples of the ceramic filler in (3) include at least one selected from the group consisting of Al ₂ O ₃ , SiO ₂ , forsterite, cordierite, mullite, AlN, Si ₃ N ₄ , SiC, MgTiO ₃ , and CaTiO _3. The glass is preferably mixed at a rate of 20 to 80% by mass with respect to the glass.

  On the other hand, the input / output signal pattern, bias pattern, terminal electrode, and vertical conductor are variously combined depending on the firing temperature of the ceramic material. For example, when the ceramic material is (1), it is selected from the group of tungsten, molybdenum, and manganese. A conductive material mainly containing at least one selected from the above is preferably used. Moreover, it is good also as a mixture with copper etc. for resistance reduction. When the ceramic material is (2), a conductor material mainly composed of at least one selected from the group consisting of copper, silver, gold, and aluminum is preferably used. The conductor material preferably contains a component constituting the ceramic material when co-firing with the ceramic material.

  Note that the above examples are merely examples of the present invention, and the present invention is not limited to these, and various modifications and improvements can be made without departing from the spirit of the present invention. .

  For example, by forming a cavity on the upper surface of the dielectric substrate 1 and housing the power amplifying element 2 in the cavity, the height and size of the module can be reduced.

  Further, as shown in FIG. 4, a high frequency switch 21 for switching to a test signal, a diplexer 22 for distributing frequency (for example, distributing a CDMA signal of 800 MHz band and a GPS signal of 1575 MHz), a Tx signal and an Rx An antenna duplexer 23 that distributes signals, an isolator 24 that absorbs reflected waves due to antenna impedance mismatch, a directional coupler 25 that monitors the output of the high-frequency power amplification module, and a signal that is input to the high-frequency power amplification module By providing the high-frequency power amplification module of the present invention with the band-pass filter 26 for increasing the purity of the present invention, the connection to each block circuit can be realized with the shortest wiring length, so that the efficiency can be increased. Moreover, the efficiency of the communication device is improved by mounting the high frequency power amplification module of FIG. 2 and the high frequency module of FIG. 4 on the portable communication device. For example, in the case of a portable communication device, the usage time by one charge is reduced. Can be extended.

1A is a schematic perspective view showing an example of a high-frequency power amplification module of the present invention, FIG. 1B is a cross-sectional view taken along A-A ′, and FIG. 1C is a cross-sectional view taken along B-B ′. It is a circuit diagram which shows an example of the high frequency power amplification module of this invention. The process drawing for forming the composite layer in this invention is shown. The circuit diagram of the high frequency module using the high frequency power amplification module of this invention is shown. 1A is a schematic perspective view showing an example of a conventional high-frequency power amplification module, FIG. 1B is a cross-sectional view taken along line A-A ′, and FIG. 1C is a cross-sectional view taken along line B-B ′.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dielectric substrate 2 ... Power amplification element 3 ... Input signal pattern 4 ... Output signal pattern 5 ... Bias patterns 6-8 ... Capacitance 9 ... Radiator 10- ..Ground electrode 11 ... Input signal terminal 12 ... Power supply terminal 13 ... Output signal terminal

Claims (9)

A dielectric substrate, a power amplification element mounted on the surface of the dielectric substrate, an input signal pattern for supplying a signal to the power amplification element, an output signal pattern for extracting a signal from the power amplification element, and the power amplification A high-frequency power amplification module having a bias pattern for supplying power to an element, wherein the input signal pattern, the output signal pattern, and the bias pattern are formed on a surface of or inside the dielectric substrate; A high-frequency power amplification module, wherein a conductor thickness of at least one of the pattern and the bias pattern is thicker than the input signal pattern. The conductor thickness t1 of the input signal pattern, the conductor thickness t2 of the output signal pattern, and the conductor thickness t3 of the bias pattern have a relationship of t2 ≧ 1.5 × t1 or t3 ≧ 1.5 × t1. The high frequency power amplification module according to claim 1. 3. The high frequency power amplification module according to claim 1, wherein at least one of the conductor thickness t2 of the output signal pattern and the conductor thickness t3 of the bias pattern is 20 [mu] m or more. At least one conductor layer of the output signal pattern and the bias pattern is formed in a composite layer in which a dielectric layer and a conductor layer having substantially the same thickness as the dielectric layer are embedded through the dielectric layer. The high-frequency power amplification module according to any one of claims 1 to 3, wherein the high-frequency power amplification module is provided. The whole is composed of a laminate of a dielectric layer and a composite layer in which a conductor layer having substantially the same thickness as the dielectric layer is embedded through the dielectric layer. The high frequency power amplification module according to any one of claims 1 to 4. 6. The high frequency power amplification module according to claim 4, wherein the composite layer has a thickness of 50 [mu] m or less. The composite layer is
(A) a step of forming a predetermined light-opaque conductor pattern layer on a surface of a light-transmissive carrier film with a conductor paste containing at least a metal powder and an organic binder;
(B) A photocuring slurry containing at least a photocurable monomer, a photopolymerization initiator, and a dielectric material on the carrier film on which the conductor pattern layer is formed has a thickness equal to or greater than the thickness of the conductor pattern layer. A step of applying a photo-curing dielectric layer to the coating,
(C) From the back surface of the carrier film, light is irradiated to photocure the photocuring dielectric layer in a region other than the formation of the conductor pattern layer, and a developer is applied to the conductor of the photocuring dielectric layer. A step of solubilizing and removing the non-photocured portion including the surface of the pattern layer to form a composite layer;
(D) firing the composite layer;
The multilayer wiring board according to claim 5 or 6, wherein the multilayer wiring board is formed. The high-frequency power amplification module according to claim 1, comprising at least one of a diplexer, an antenna duplexer, a directional coupler, an isolator, a high-frequency switch, and a band-pass filter. A portable terminal device comprising the high-frequency module according to any one of claims 1 to 8.

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