JP2008034778A - Circuit module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact circuit module excellent in heat dissipation. <P>SOLUTION: The circuit module is composed of: a plurality of electronic components 3 including a heat generating component 3a, a wiring substrate 2 that has an internal wiring 4 and is mounted with the plurality of electronic components 3, an insulating resin 5 that covers the plurality of electronic components 3 except for at least a part of the heat generating component 3a, and a heat radiation layer 6 that covers the part not covered with the insulating resin 5 of the heat generating component 3a and a top surface of the insulating resin 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a circuit module such as a GPS module or a W-LAN (wireless run) module.

  In recent years, circuit modules in which a plurality of electronic components are mounted on a wiring board are rapidly spreading. These circuit modules are used in, for example, wireless communication devices such as mobile phones and have a function of processing high-frequency signals.

  The plurality of electronic components mounted on the wiring board includes a heat-generating component that generates heat such as Joule heat when the circuit module is used. If the heat generated from the exothermic component is not dissipated to the outside, excessive heat builds up in the exothermic component itself, resulting in large fluctuations in the electrical characteristics of the exothermic component and unstable circuit module operation. Become.

Therefore, in order to release heat generated from the heat-generating component to the outside of the circuit module, a heat dissipation structure in which a plurality of thermal via conductors are provided on the wiring board has been conventionally used. Specifically, a plurality of thermal via conductors penetrating the wiring board are provided in a region immediately below the heat-generating component of the wiring board, and the thermal via conductors are connected to a heat radiating pad installed on the lower surface of the wiring board. The heat generated in the heat-generating component is conducted to the heat dissipating pad through the thermal via conductor and released to the outside of the circuit module (see, for example, Patent Document 1).
JP 2004-172176 A

  By the way, many internal wirings are provided in the inside of the wiring board which comprises a circuit module. However, in the case of the above-described conventional circuit module, the heat dissipating structure including a plurality of thermal via conductors is provided in the wiring board in addition to the internal wiring, so that the internal structure of the wiring board becomes very complicated. Moreover, both must be formed so that the thermal via conductor and the internal wiring do not come into contact with each other, and the position where the thermal via conductor or the internal wiring is formed is restricted. For these reasons, in the conventional circuit module on which the heat generating component is mounted, the wiring board is enlarged, and it is difficult to reduce the overall structure of the circuit module.

  The present invention has been devised in view of the above problems, and an object thereof is to provide a circuit module that is small in size and excellent in heat dissipation.

The circuit module of the present invention includes a heat generating component, a wiring board on which the heat generating component is mounted,
An insulating resin that covers at least a lower region of the exothermic component; and a heat dissipation layer that is provided on the insulating resin and that is partly attached to at least a part of the upper surface and the side surface of the exothermic component; It is characterized by comprising.

  The circuit module of the present invention includes a plurality of electronic components including a heat-generating component, a wiring board having internal wiring and mounting the plurality of electronic components, and at least a part of the heat-generating component. The insulating resin that covers the plurality of electronic components except, and a heat dissipation layer that covers the portion of the heat generating component that is not covered with the insulating resin and the upper surface of the insulating resin, To do.

  In the circuit module of the present invention, the heat dissipation layer is made of a sintered metal.

  The circuit module of the present invention is characterized in that the heat dissipation layer is electrically connected to a ground conductor.

  In the circuit module of the present invention, an upper portion of the heat generating component is embedded in the heat dissipation layer.

  In the circuit module of the present invention, the height position of the upper surface of the exothermic component is higher than the height position of the upper surface of the other electronic component, and the height position of the upper surface of the insulating resin and the exothermic component The height position of the upper surface of each is equal.

  The circuit module of the present invention is characterized in that a plurality of grooves are provided in the heat dissipation layer.

  In the circuit module of the present invention, the plurality of electronic components include components having large temperature characteristic fluctuations, and a shielding layer is provided between the heat generating component and the parts having large temperature characteristic fluctuations. In addition, the shielding layer is connected to the heat dissipation layer.

  The circuit module of the present invention is characterized in that the heat generating component is a semiconductor component incorporating a power amplifier.

  According to the circuit module of the present invention, most of the heat generated from the heat-generating component is released to the outside through the heat dissipation layer. Therefore, the heat generated from the heat-generating components can be released to the outside without providing a complicated heat dissipation structure inside the wiring board, so that the internal structure of the wiring board is simplified and the internal wiring can be freely designed. The degree can be improved. As a result, it is possible to reduce the size of the wiring board, and consequently to reduce the overall structure of the circuit module.

  Hereinafter, a circuit module of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an external perspective view of a circuit module according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the circuit module shown in FIG.

  A circuit module 1 shown in FIG. 1 includes a plurality of electronic components 3 arranged in parallel on the wiring substrate 2 and the wiring substrate 2, an insulating resin 5 that covers the plurality of electronic components, and a heat dissipation that covers the insulating resin 5. Layer 6 is provided. The plurality of electronic components 3 includes a heat generating component 3a and other electronic components 3b.

  The wiring board 2 is a substantially rectangular parallelepiped substrate having a size of 7 mm × 5 mm × 0.4 mm, for example, and is formed by laminating a plurality of insulating layers mainly composed of a ceramic material such as glass-ceramics, alumina, and mullite. ing. In particular, when the circuit module 1 is used in a high-frequency device, it is desirable to use a glass-ceramic material for the wiring board 2. By using a glass-ceramic material, Cu or Ag, which are low resistance conductors, can be easily used as wiring. This wiring substrate 2 is a screen printing of a well-known screen paste with a conductive paste serving as a circuit wiring or connection pad on the surface of a ceramic green sheet obtained by adding and mixing an appropriate organic solvent to a ceramic material powder such as a glass-ceramic material. It is manufactured by coating by a method or the like, laminating a plurality of these and press-molding, followed by firing at a high temperature.

  Internal wiring 4 is provided inside such a wiring board 2. The internal wiring 4 includes a wiring pattern 4a disposed between the insulator layers and a via-hole conductor 4b penetrating the insulator layer.

  Further, external terminals 7 are formed on the lower surface of the wiring board 2, and electrode pads 8 for mounting the electronic components 3 are formed on the upper surface.

  The internal wiring 4, the external terminal 7, the electrode pad 8, and the like described above are made of a material mainly containing a metal such as Ag, Cu, W, and Mo. For example, Ag-based powder, borosilicate-based low-melting glass frit, ethyl cellulose A conductive paste containing an organic binder, an organic solvent, etc. is applied on a ceramic green sheet serving as each insulator layer constituting the wiring board 2 by conventional screen printing or the like, and then fired. Is done.

  On the wiring board 2, a heat generating component 3a and other electronic components 3b are mounted.

  The exothermic component 3a is an electronic component that consumes relatively large power and easily generates Joule heat. In this embodiment, a semiconductor component incorporating a power amplifier is used. As shown in the plan view of FIG. 3 (the electronic component 3 is indicated by a dotted line), the heat-generating component 3a is preferably arranged so as to be positioned at the center of the heat radiation layer 6 in a plan view of the circuit module 1. By disposing the exothermic component 3a in this way, the thermal diffusibility is improved, and the heat from the exothermic component 3a can be efficiently radiated.

  On the other hand, the other electronic component 3b includes a capacitor, a resistor, an inductor, a SAW filter, and a crystal oscillator. A predetermined circuit is configured by electrically connecting the electronic component 3 and the internal wiring 4 to each other.

  These electronic components 3 are covered with an insulating resin 5 except at least a part of the heat-generating component 3a.

  The insulating resin 5 is formed of an insulating resin material such as a phenol resin or an epoxy resin. The insulating resin 5 is protected by covering a part of the heat-generating component 3a and other electronic components 3b, and the circuit module. 1 has the function of increasing the mechanical strength of itself.

  This insulating resin 5 is applied to the upper surface side of the wiring board 2 so as to cover the upper surfaces of the electronic component 3 and the wiring board 2 by a conventionally known screen printing method or the like. At this time, a part of the heat generating component 3 a is not covered with the insulating resin 5. This is because the heat radiation layer 6 is attached to the heat generating component 3a. In the present embodiment, the insulating resin 5 is patterned so that a plurality of passages 9 can be provided on the heat generating component 3a. That is, a plurality of locations on the top surface of the heat-generating component 3 a are exposed at the bottom surface of the passage 9. In addition, after forming the insulating resin 5 so that the whole exothermic component 3a is covered, a hole or a groove reaching the upper surface of the exothermic component 3a from the upper surface of the insulating resin 5 is formed using a laser beam or the like. Thus, the passage 9 may be formed. The applied insulating resin 5 is cured, for example, by heating at 150 ° C. for about 30 minutes.

  The passages 9 formed on the upper surface side of the exothermic component 3a have, for example, a circular planar shape as shown in FIG. 3, and are arranged uniformly over the entire upper surface of the exothermic component 3a. The shape, arrangement, and the like of the passage 9 can be changed as appropriate. For example, when the exothermic component 3a has a biased heat generation temperature distribution, the passage 9 may be formed only in a portion where the heat generation temperature tends to increase. When the portion where the temperature is likely to rise is located in the central region of the exothermic part 3a, as shown in FIG. 9 (a), the passages 9 may be formed so as to be concentrated in the central region of the exothermic component 3a. Alternatively, as shown in FIG. 9B, the planar shape of the passage 9 located at the center of the exothermic component 3a may be formed to be large. Thus, by providing a heat dissipation structure on the upper surface side of the exothermic component 3a, the formation density, the formation size, etc. of the passages 9 are adjusted in accordance with the exothermic temperature distribution of the exothermic component 3a so that the generated heat is efficiently dissipated. Can be changed. Thereby, the electrical performance and reliability performance of the circuit module can be further improved. The passage 9 can have an arbitrary shape such as a polygonal planar shape or a stripe shape.

  The upper surface of the insulating resin 5 is covered with the heat dissipation layer 6, and the heat dissipation layer 6 is filled in the passage 9, so that the upper surface of the heat-generating component 3 a exposed on the bottom surface of the passage 9 is covered with the heat dissipation layer 6. It will be coated.

  Examples of the heat dissipation layer 6 include a conductive resin, a metal film formed by vapor deposition or plating, and the like, but from the viewpoint of productivity, it is preferable to form a metal sintered body made only of sintered metal particles such as Ag. In addition, when the circuit module 1 is incorporated in a mobile phone or the like that handles radio frequencies of 800 MHz or higher, a metal sintered body is particularly effective from the viewpoint of electromagnetic shielding. The metal sintered body contains substantially no resin component such as a binder and is obtained by sintering metal fine particles. In this metal sintered body, metal nanoparticles having an average particle diameter of 1 nm to 100 nm, more preferably an average particle diameter of 10 nm to 50 nm are dispersed in an organic dispersion solvent such as toluene, terpineol, xylene, tetradecane, After forming into a paste, it is formed by applying it on the upper surface of the insulating resin 5 and subjecting it to a heat treatment at 130 to 300 ° C. Thus, by using the nano-order metal particles, a dense metal layer can be formed, and a layer having extremely excellent thermal conductivity and heat dissipation can be obtained, and the heat generated from the exothermic component 3a can be efficiently It can be released to the outside well. In addition, since nano-order metal particles are sintered at a relatively low temperature of 130 to 300 ° C., the heat-dissipating layer 5 is formed without causing deterioration of the insulating resin 5 and the electronic component 3 due to high-temperature heating. it can.

  In addition to Ag, Cu, Ni, or the like can be used as a material for the metal sintered body. Moreover, the thickness of the thermal radiation layer 5 by a metal sintered compact is set to 5-10 micrometers, for example.

  According to the circuit module 1 of the present invention described above, most of the heat generated from the exothermic component 3 a is released to the outside through the heat dissipation layer 6. That is, since the heat of the heat generating component 3a can be released to the outside without providing a complicated heat dissipation structure made of a thermal via conductor or the like on the wiring board 2, the internal structure of the wiring board 2 is simplified, The degree of freedom in designing the internal wiring 4 can be improved. Thereby, the wiring board 2 can be reduced in size, and as a result, the entire structure of the circuit module 1 can be reduced in size.

  FIG. 4 is a cross-sectional view showing a modification of the first embodiment. The characteristic of the circuit module shown in FIG. 2 is that the heat dissipation layer 6 is electrically connected to the ground conductor 10 provided on the wiring board 2. The ground conductor 10 is a conductor that is held at the ground potential when the circuit module is used. By electrically connecting the heat dissipation layer 6 to the ground conductor 10, the electromagnetic shielding function of the heat dissipation layer 6 is enhanced. Can do. As a result, the electronic component 3 mounted on the wiring board 2 is electromagnetically shielded, and it is possible to prevent malfunction of the electronic component due to unnecessary electromagnetic waves from the outside, fluctuation of electrical characteristics, and the like. Can be operated more stably. The ground conductor 10 is connected to the external terminal 7 for ground potential via the internal wiring 4.

  FIG. 5 is a sectional view showing a second embodiment of the circuit module 1 according to the present invention. In addition, the description which overlaps using the same code | symbol for the component similar to 1st Embodiment is omitted (it is the same also about the following embodiment). What is characteristic in the present embodiment is that the upper portion of the heat generating component 3 a is embedded in the heat dissipation layer 5. By embedding the upper part of the heat generating component 3a in the heat dissipation layer 5, the contact area between the heat generating component 3a and the heat dissipation layer 5 is increased, and the heat generated in the heat generating component 3a is more efficiently transmitted to the outside. Can be released. The upper part of the heat generating component 3a is the upper half area of the heat generating component 3b main body.

  FIG. 6 is a sectional view showing a third embodiment of the circuit module 1 according to the present invention. What is characteristic in the present embodiment is that the height position of the upper surface of the heat generating component 3a is higher than the height position of the upper surface of the other electronic component 3b and the height position of the upper surface of the insulating resin 5 and the heat generation. This is a point where the height position of the upper surface of the functional part 3a is equal. By making the height position of the upper surface of the insulating resin 5 equal to the height position of the upper surface of the heat generating component 3a, it is possible to reduce the height of the circuit module while flattening the upper surface of the heat dissipation layer 6. That is, when the heat dissipation layer 6 is formed so as to cover the upper surface of the insulating resin 5 when the upper surface of the insulating resin 5 is lower than the upper surface of the tallest heat-generating component 3, the heat-dissipating layer 6 becomes the heat-generating component 3 a. The part corresponding to is projected. On the other hand, if the height position of the upper surface of the insulating resin 5 and the height position of the upper surface of the heat-generating component 3a are made equal, the heat radiation layer 6 formed on the insulating resin 5 also has large unevenness. Will not be formed. Thus, for example, when the circuit module 1 is sucked and transported, suction can be reliably performed, and productivity can be improved. In addition, since the insulating resin 5 is not interposed between the upper surface of the heat generating component 3a and the heat radiation layer 6, the circuit module 1 can be reduced in height.

  FIG. 7 is a sectional view showing a fourth embodiment of the circuit module 1 according to the present invention. What is characteristic in the present embodiment is that a plurality of grooves 11 are provided in the heat dissipation layer 6. By providing the plurality of grooves 11 in the heat dissipation layer 6 in this manner, the surface area of the heat dissipation layer 6 is increased, and the heat dissipation performance to the outside can be improved.

  FIG. 8A is a cross-sectional view showing a fifth embodiment of the circuit module 1 according to the present invention, and FIG. 8B is a plan view. What is characteristic in the present embodiment is that the plurality of electronic components 3 include a component 3c having a large temperature characteristic variation, and a shielding layer 12 that partitions the heat generating component 3a and the component 3c having a large temperature property variation. This is the point. The shielding layer 12 is connected to the heat dissipation layer 6 and can suppress the heat generated from the exothermic component 3a from being transmitted to the component 3c having a large temperature characteristic fluctuation. As a result, it is possible to prevent the electrical characteristics of the component 3c having a large temperature characteristic fluctuation from being greatly fluctuated by heat, and to operate the circuit module 1 more stably. The shielding layer 12 is preferably formed of a metal sintered body made only of sintered metal particles such as Ag for the same reason as the heat dissipation layer 5, and after the passage 9 is formed in the insulating resin 5, the passage 9 is filled with a precursor of a metal sintered body and heat-treated. Also, if the shielding layer 12 is connected to the ground conductor 10, the electronic component 3 mounted on the wiring board 2 is electromagnetically shielded, and the influence on the electronic component 3 due to unnecessary electromagnetic waves from the outside is exerted. Therefore, the circuit module 1 can be operated more stably. Therefore, it is preferable to connect the shielding layer 12 to the ground conductor 10. Examples of the component 3c having a large temperature characteristic fluctuation include a SAW filter and a crystal oscillator.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

  In the above-described embodiment, the example of the circuit module having the highest height position of the upper surface of the exothermic component 3a among the plurality of electronic components 3 has been described. However, the height position of the upper surface of the exothermic component 3a is different from the others. The present invention is applicable even when the height is lower than the height position of the upper surface of the electronic component 3b. In this case, as shown in FIG. 10, a passage 9 having a height matching the distance between the heat radiation layer 6 and the heat-generating component 3 a is formed, and a part of the heat radiation layer 6 is filled in the passage 9. What should I do?

1 is an external perspective view of a circuit module according to a first embodiment of the present invention. It is sectional drawing of the circuit module shown in FIG. It is a top view of the circuit module shown in FIG. It is sectional drawing which shows the modification of the circuit module which concerns on the 1st Embodiment of this invention. It is sectional drawing of the circuit module which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the circuit module which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the circuit module which concerns on the 4th Embodiment of this invention. (A) is sectional drawing of the circuit module which concerns on the 5th Embodiment of this invention, (b) is a top view. It is a top view of the circuit module shown in FIG. 1, (a) is what changed the arrangement | positioning of a channel | path, (b) is what changed the shape of the channel | path. It is sectional drawing of the circuit module which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Circuit module 2 ... Wiring board 3 ... Electronic component 4 ... Internal wiring 5 ... Insulating resin 6 ... Heat dissipation layer

Claims (9)

Exothermic parts,
A wiring board on which the exothermic component is mounted;
An insulating resin covering at least the lower region of the heat-generating component;
A circuit module comprising: a heat-dissipating layer provided on the insulating resin and partially attached to at least a part of an upper surface and a side surface of the heat-generating component. A plurality of electronic components including exothermic components;
A wiring board having internal wiring and on which the plurality of electronic components are mounted;
An insulating resin that covers the plurality of electronic components except at least a portion of the heat-generating component; and
The circuit module provided with the part which is not coat | covered with the said insulating resin of the said exothermic component, and the thermal radiation layer which coat | covers the upper surface of the said insulating resin. The circuit module according to claim 2, wherein the heat dissipation layer is made of a sintered metal. The circuit module according to claim 3, wherein the heat dissipation layer is electrically connected to a ground conductor. The circuit module according to claim 4, wherein an upper portion of the heat generating component is embedded in the heat dissipation layer. The height position of the upper surface of the exothermic component is higher than the height position of the upper surface of another electronic component, and the height position of the upper surface of the insulating resin and the height position of the upper surface of the exothermic component are The circuit module according to claim 2, wherein the circuit modules are equal. The circuit module according to claim 2, wherein a plurality of grooves are provided in the heat dissipation layer. The plurality of electronic components include components having a large temperature characteristic variation, and a shielding layer is provided between the heat-generating component and the component having a large temperature property variation, and the shielding layer The circuit module according to claim 2, wherein the circuit module is connected to the heat dissipation layer. The circuit module according to claim 2, wherein the heat-generating component is a semiconductor component incorporating a power amplifier.

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