JP2005183430A - Module comprising electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a module comprising electronic component which assures excellent close contact property and connection property in a module structure and enables reliable assembly and mounting. <P>SOLUTION: The module comprising electronic component includes at least one or more electronic components 4, electrode 3 for mounting electronic component 4 at the surface layer and a solder resist 6. A circuit board 2 including one or more wiring layers and electronic component 4 are bonded to the electrode 3 of the circuit board 2 with the solder 5, and these are covered with an insulating resin 7. In this module comprising electronic components, a part or the entire part of the solder resist 6 at the external circumference of the circuit board 2 are removed and the insulating resin 7 joins and hermetically seals with the removing portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic component built-in module in which various electronic components are mounted on a wiring board and covered with an insulating resin.

  In recent years, small electronic devices in which a plurality of electronic components are mounted and mounted on a high-density wiring board, or modules constituting the electronic devices have been rapidly spread. Conventionally, this type of module has a structure in which an electronic component is covered with a metal case or the whole is housed in a metal case for the purpose of protection from electromagnetic field or electrostatic field noise.

  Further, as an alternative to these metal cases, recently, resin-molded electronic components built-in as disclosed in JP-A-11-163583, JP-A-2001-24312 and JP-A-2001-168493 are disclosed. Modules have been proposed. Further, by reinforcing the electronic parts mounted by the resin mold and forming the module itself in a square block, it is easy to mount the final electronic device.

  FIG. 7 is a schematic cross-sectional view of a conventional electronic component built-in module of this type, and a circuit pattern 20 made of a conductive material and electrodes 23 are laminated on one surface (surface layer) of a plurality of layers. A solder resist 26 is formed on one surface (surface layer) excluding the electrode 23.

  Then, after the electronic component 24 and the electrode 23 are mechanically and electrically joined (connected) by the solder 25, a solder terminal 28 for mounting on the electronic device is formed, and the wiring board 22 is wrapped so as to enclose the electronic component 24. One surface (surface layer) is covered with an insulating resin 27, and a shield layer 29 against an electromagnetic field or an electrostatic field caused by metal plating is provided on the outer surface of the electronic component built-in module 21.

As prior art document information related to this application, for example, Patent Document 1 is known.
JP 2001-168493 A

  However, the conventional electronic component built-in module has a configuration in which an electronic component and a wiring board are mechanically and electrically joined (connected) with solder and covered with an insulating resin from above. Moisture and moisture permeated from between the wiring board and the wiring board are turned into water vapor at the intimate contact between the insulating resin and the wiring board due to high temperatures when the electronic component built-in module is joined (connected) with the mother board and solder in the electronic device. Will change.

  At that time, a strong expansion force due to water vaporization works to generate a gap between the insulating resin and the wiring board. Furthermore, since the solder is remelted in the electronic component built-in module, the molten and expanded solder may flow out to the gap portion between the insulating resin and the wiring board.

  As a result, a short circuit occurs between the solders and between the electrodes, which hinders the function of the electronic component built-in module. In addition, the adhesive force between the solder resist applied to the upper surface (surface layer) of the wiring board and the insulating resin is not sufficient, and there is a problem that a gap is easily generated between the insulating resin and the solder resist.

  The present invention is intended to solve the above-described problems, and provides an electronic component built-in module that has excellent adhesion and connectivity in a module configuration, and can be reliably and highly reliably assembled and mounted on an electronic device. It is intended.

  In order to achieve the above object, the present invention has the following configuration.

  The invention described in claim 1 of the present invention particularly has at least one or more electronic components, an electrode for mounting the electronic components on a surface layer, and a solder resist, and has at least one wiring layer. In the electronic component built-in module in which the wiring board and the electronic component are joined to the wiring board electrode and solder, and these are covered with an insulating resin, part or all of the solder resist on the outer peripheral portion of the wiring board is removed, The insulating resin is filled so as to be directly bonded to the removed portion, and thereby, the surface roughness due to the material and the forming process, the forming strength, the internal density and the structure of the composition Due to the difference, the wiring substrate and the insulating resin, which have higher adhesion than the solder resist, will be bonded and intimately bonded, and moisture and moisture will penetrate between the insulating resin and the wiring substrate. In addition, the adhesion between the insulating resin and the wiring board can be strengthened, and when the module with built-in electronic components is mounted on the mother board in an electronic device, the moisture contained in the solder resist and the module is heated. This has the effect of preventing generation of a gap between the insulating resin and the wiring board caused by steaming.

  The invention according to claim 2 of the present invention particularly has at least one or more electronic components, and an electrode and a solder resist for mounting the electronic components on a surface layer, and has at least one wiring layer. In the electronic component built-in module in which the wiring board and the electronic component are joined to the wiring board electrode with solder and covered with insulating resin, a part of the solder resist near the mounted electronic component on the wiring board is removed. In addition, the insulating resin is filled so as to be directly bonded to the removed portion, whereby the insulating resin is bonded and adhered to the wiring substrate having higher adhesion than the solder resist. As a result, the adhesion between the insulating resin and the wiring board can be further strengthened. When, with the effect that it is possible to further prevent the gap generation between the insulating resin caused by the water vapor of the water which was included with the wiring board.

  The invention described in claim 3 of the present invention particularly has a configuration in which a shield layer by metal plating is provided on the surface layer of the insulating resin. In addition, there is an effect that moisture and moisture hardly penetrate into the entire electronic component built-in module.

  The invention described in claim 4 of the present invention particularly has a configuration in which the solder resist removal portion in the vicinity of the electronic component on the wiring board is connected to the solder resist removal portion on the outer peripheral portion. As a result, the parts with strong adhesion are connected and continuous, and when the electronic component built-in module is mounted on the mother board in the electronic device, the insulation resin and the wiring board that are caused by the water vaporization of the contained water It is possible to more reliably prevent the occurrence of the gap.

  The invention according to claim 5 of the present invention particularly has a configuration in which a part of the solder resist in the vicinity of a plurality of electronic components is removed and the removed portions are connected, thereby providing an adhesive force. When the module with a built-in electronic component is mounted on the mother board in an electronic device, the gap between the insulating resin and the wiring board caused by the water vaporization included is more It has the effect that it can prevent reliably.

  The invention according to claim 6 of the present invention has a configuration in which a part of the solder resist in the vicinity of the electronic component is removed to form a plurality of removed portions, thereby providing strong adhesion. Many parts will exist widely, and when mounting the module with built-in electronic components on the mother board in electronic equipment, the gap between the insulating resin and the wiring board caused by the water vaporization of the contained water is more reliably generated. It has the effect that it can prevent.

The invention described in claim 7 of the present invention has a configuration in which an electronic component is mounted on a wiring board and mounted, and O ₂ ashing treatment is performed before the electronic component is covered with an insulating resin. Then, unnecessary organic films or oxides on the surface of the wiring board and the electronic component are removed, and there is an effect that the adhesion between them and the insulating resin can be further strengthened.

  The invention according to claim 8 of the present invention particularly has a configuration in which an electronic component is mounted and mounted on a wiring board, and a silane coupling agent coating treatment is performed before covering it with an insulating resin, Thereby, it has the effect that the adhesion | attachment with the surface and insulating resin in a wiring board or an electronic component can be strengthened.

The invention according to claim 9 of the present invention is particularly configured such that an electronic component is mounted on a wiring board and mounted, and O ₂ ashing treatment and silane coupling agent coating treatment are performed before the electronic component is covered with an insulating resin. Accordingly, a synergistic action and a synergistic effect occur, and the adhesion between the surface of the wiring board or electronic component and the insulating resin can be further enhanced.

  In the invention according to claim 10 of the present invention, in particular, a configuration in which the solder resist removed portion of the wiring board or the wiring pattern exposed in the removed portion is covered with an insulating resin after being subjected to cloth or roughening. As a result, it is possible to prevent a decrease in the adhesion force with the insulating resin, and the effect of further strengthening the adhesion between the wiring board and the insulating resin.

  The invention according to claim 11 of the present invention has a configuration in which the water absorption rate of the wiring board is not more than 0.3% under the standing condition of 60 ° C., 60%, and 20H. Water absorption of the wiring board can be suppressed, and when mounting a module with built-in electronic components on a mother board in an electronic device, between the insulating resin and the wiring board, or between the solder resist and the wiring board, which is caused by the water vapor contained therein It is possible to more reliably prevent the occurrence of the gap.

  The invention according to claim 12 of the present invention has a configuration in which the insulating resin is a mixture of an inorganic filler and a thermosetting resin. It has an effect that the characteristics such as the permittivity and the dielectric constant can be adjusted and set.

  The invention described in claim 13 of the present invention has a configuration in which the expansion coefficient of the insulating resin is particularly 30 ppm or less, whereby the expansion coefficient of the insulating resin is changed to the thermal expansion coefficient of the wiring board or electronic component. It is possible to reduce the internal stress in the electronic component built-in module and prevent the occurrence of distortion and cracks.

  The invention according to the fourteenth aspect of the present invention has a configuration in which the insulating resin particularly has a flexural modulus of 20 Gpa or less, whereby a flexible insulating resin is obtained, and the solder is remelted. It has the effect of absorbing and relaxing the expansion and preventing the outflow of solder to other than the electrodes and connection parts of the electronic component.

  The module with a built-in electronic component according to the present invention has a configuration in which part or all of the solder resist on the outer peripheral portion of the surface layer of the wiring board is removed or part of the solder resist in the vicinity of the electronic component is removed. The adhesion between the insulating resin and the wiring board can be strengthened by preventing moisture and moisture from penetrating from the interface with the wiring board and bonding the insulating resin to the wiring board that has stronger adhesion than the solder resist. When mounting a module with built-in electronic components on a mother board in an electronic device, the gap between the insulating resin and the wiring board caused by rapid volume expansion due to water vaporization contained in the module is prevented and remelted. This has the effect of preventing the solder that has flown out of the predetermined electrode.

(Embodiment 1)
In the following, the first aspect of the present invention will be described with reference to the drawings.

  Note that the same components and the like as those described in the background art are assigned the same reference numerals and detailed description thereof is omitted.

  FIG. 1 is a schematic sectional view of an electronic component built-in module according to an embodiment of the present invention, FIG. 2 is a schematic plan view of the wiring board, and FIG. 3 is a schematic diagram of a wiring board containing the same number of electronic components. It is a top view.

  In FIG. 1, an electronic circuit of the electronic component built-in module 1 constitutes an electronic circuit, and a wiring board 2 made of an insulating material includes an electrode 3 made of a conductive material on the surface layer (upper surface), a wiring pattern 11, and an inner layer (inside). Wiring pattern 12, and inner via 10 that electrically connects wiring pattern 11 and wiring pattern 12, back electrode 13 on the back layer (lower surface), and solder resists 6 and 16 applied to the surface layer and the back layer. It is the formed multilayer wiring board.

  The wiring patterns 11 and 12 are made of a material having electrical conductivity, for example, Cu (copper) foil or various conductive resin compositions, and Cu foil is used in the present embodiment. The inner via 10 is a thermosetting electric conductive material made of a conductive resin composition in which, for example, metal particles and a thermosetting resin are mixed. As the metal particles, Au, Ag, Cu, or the like is used. Can do.

  Au, Ag, or Cu as the metal particles is preferable because of high electrical conductivity and thermal conductivity, and Cu is more preferable because of its high electrical conductivity, low migration, and low cost.

  As the thermosetting resin, for example, an epoxy resin, a phenol resin, or a cyanate resin can be used. Among them, the epoxy resin is more preferable because of its high heat resistance.

  The electronic component 4 is mounted and mounted on a predetermined portion of the surface layer (upper surface) of the wiring board 2 using solder 5. The electronic component 4 is made of, for example, an active component, a passive component, or a composite thereof. A semiconductor element such as a transistor, a diode, an IC, or an LSI is used as the active component, and a chip such as a resistor, a capacitor, or an inductor is used as the passive component. Parts, vibrators, filters, etc. are used.

  For the solder 5, Pb—Sn eutectic solder or Pb free solder (for example, Sn—Ag—Cu, Au—Sn, or Sn—Zn) can be used. In any case, the melting point is 230. It is desirable that even a non-heat-resistant electronic component can be used at a temperature not higher than ° C.

  Further, the solder 5 for bonding and mounting the electronic component 4 and the solder terminal 14 for mounting the electronic component built-in module 1 on a mother board (not shown) in the electronic device may be made of the same material. Different materials may be used. However, in consideration of recent environmental problems, it is preferable to use Pb-free solder.

The insulating resin 7 is applied so as to completely cover the entire electronic component 4, and the insulating resin 7 is made of a mixture containing an inorganic filler and a thermosetting resin. As the inorganic filler, for example, Al ₂ O ₃ , MgO, BN, AlN, SiO ₂ and BaTiO ₃ can be used.

  As the thermosetting resin, an epoxy resin, a phenol resin, or a cyanate resin is preferable. Of these, an epoxy resin is more preferable because of its high heat resistance. If necessary, a shield layer 15 made of a metal film by plating may be formed on the outer surface layer of the insulating resin 7 so as to act as a shield against an electromagnetic field or an electrostatic field.

  The shield layer 15 of the metal film by plating is formed by using at least one material such as Au, Ag, Cu, Ni, Fe, Cr, Zn, Ti, and Al.

  In the embodiment shown in FIGS. 2 and 3, the solder resist 6, 6 a on the outer peripheral portion (edge) of the surface layer in the wiring substrate 2 is removed, and the solder resist removed portion in the surface layer of the wiring substrate 2 is removed. 17 and 17a are provided.

  As shown in FIGS. 1 to 3, in the electronic component built-in module 1 of the present invention, the outer peripheral portion (edge portion) of the wiring board 2 has the solder resists 6 and 6a removed, The insulating resin 7 joins and adheres to the surface (surface layer) of the wiring board 2 having higher adhesion than the solder resists 6 and 6a due to differences in surface roughness, formation strength, and internal density configuration due to materials and forming processes. Will do.

  As a result, moisture and moisture are prevented from penetrating into the module from between the insulating resin 7 and the wiring board 2 and the adhesion between the insulating resin 7 and the wiring board 2 is also improved. When the electronic component built-in module 1 is mounted, it is possible to prevent generation of a gap between the insulating resin 7 and the wiring board 2 caused by rapid volume expansion due to moisture or water vapor contained in the module.

In addition, since the electronic component 4 mounted and mounted on the wiring board 2 is subjected to O ₂ ashing treatment before being covered with the insulating resin 7, an organic film on the surface of the wiring board 2 or the electronic component 4 can be removed. Adhesion between them and the insulating resin 7 can be further strengthened.

Alternatively, it is also effective to perform a silane coupling agent coating treatment, and the adhesion between the surface of the wiring board 2 or the electronic component 4 and the insulating resin 7 can be strengthened. Then, after the O ₂ ashing treatment, these actions and effects can be further enhanced by performing a silane coupling agent coating treatment.

  Furthermore, the circuit pattern 11 exposed in the portions 17 and 17a from which the solder resist has been removed and the portions from which the solder resists 6 and 6a have been removed may remain as a Cu material or may be roughened, and a separate Au plating process may not be performed. desirable.

  This is because Au plating has insufficient adhesion as compared to Cu or other metal materials or their plating, and when the wiring board 2 absorbs water, the moisture is absorbed in the wiring board 2 or the solder resist 6, In the interface with 6a or the insulating resin 7, it expands when it becomes water vapor by heating, and a peeling phenomenon may occur between them due to the expansion force.

  Therefore, the water absorption rate of the wiring board 2 is preferably as low as possible, but it is desirable that the water absorption rate (when left under conditions of 60 ° C., 60%, and 20H) is 0.3% or less in the experimental results.

  With the above structure and construction method, moisture and moisture permeation from the interface between the insulating resin 7 and the wiring board 2 to the inside of the electronic component built-in module 1 are prevented, and the adhesion between the insulating resin 7 and the wiring board 2 is further strengthened. Therefore, the electronic component built-in module 1 is also included in the electronic component built-in module 1 when the solder 5 is remelted when the electronic component built-in module 1 is mounted on a mother board (not shown) in the electronic device. Generation of a gap between the insulating resin 7 and the wiring board 2 caused by rapid expansion of the volume due to water vaporization can be prevented, and as a result, the solder 5 can be prevented from flowing out and a short circuit due to the electrode 3 can be prevented. be able to.

  At this time, it is important that the bending elastic modulus of the insulating resin 7 is 20 Gpa or less. When a material having a bending elastic modulus of 20 Gpa or more is used for the insulating resin 7, stress acts on the insulating resin 7 due to the volume expansion at the time of remelting of the solder 5, but since the bending elastic modulus is high, the volume expansion of the solder 5 is increased. Suppressing stress also works.

  This stress cannot be balanced, and as a result, a crack is generated in the insulating resin 7, and the melted solder 5 flows out to the crack portion, resulting in deterioration of characteristics.

  However, when the bending elastic modulus of the insulating resin 7 is set to 20 Gpa or less, the insulating resin 7 can deform and follow the volume expansion when the solder 5 melts. For this reason, the insulating resin 7 is not cracked, and the molten solder 5 can be prevented from flowing out. Therefore, the short circuit caused by the solder 5 does not occur, and the characteristics and functions of the electronic component built-in module 1 are deteriorated. There is nothing.

  Furthermore, if the expansion coefficient of the insulating resin 7 is small, preferably 30 ppm or less, the above characteristics can be further improved.

  As described above, in Embodiment 1 of the present invention, part or all of the solder resist on the outer peripheral portion (edge) of the surface layer in the wiring board is removed, so that the electronic component is embedded from the interface between the insulating resin and the wiring board. While preventing moisture or moisture from penetrating into the module, it is possible to further strengthen the adhesion between the insulating resin and the wiring board. When the module with built-in electronic components is mounted on the mother board in an electronic device, it is remelted. It is possible to prevent the solder from flowing out of the predetermined electrode.

  In addition, as described above, it is important to use a material having a bending elastic modulus of 20 Gpa or less for the insulating resin. By doing so, it is possible to follow the expansion of the remelted solder, and the insulating resin is cracked. This makes it possible to prevent the solder from flowing out.

(Embodiment 2)
Next, the second aspect of the present invention will be described with reference to the drawings.

  4 is a schematic cross-sectional view of an electronic component built-in module according to Embodiment 2 of the present invention, FIG. 5 is a schematic plan view of the wiring board, and FIG. 6 is a schematic diagram of a wiring board containing the same number of electronic components. It is a top view. 4 is a side cross-sectional view of FIG. 1 of the first embodiment.

  As shown in FIGS. 4 and 5, the solder resist 6 in the vicinity (between) the electronic components 4 is removed, and a solder resist removal portion 17b is provided. In this way, the insulating resin 7 is bonded and adhered to the surface layer (upper surface) of the wiring board 2 having higher adhesion than the solder resist 6, so that the adhesion force between the insulating resin 7 and the wiring board 2 is achieved. Therefore, when the circuit component built-in module 31 is mounted on a mother board in an electronic device, the insulating resin causes a rapid volume expansion due to water vaporization contained in the electronic component built-in module 31. Generation of a gap between the wiring board 2 and the wiring board 2 can be prevented.

Further, O ₂ ashing, application of a silane coupling agent, low moisture absorption of the wiring substrate 2, or the exposed circuit pattern 11 and the elastic modulus and expansion coefficient of the insulating resin 7 are the same as those in the first embodiment described above. If it does, it will have much more excellent operation | movement and an effect.

  FIG. 6 shows an example in which the solder resist 6a is removed from the wiring board 2 on which various electronic components 4 are mounted and mounted, and a solder resist removal portion 17c is provided.

  In this case, the solder resist removal portion 17c has a shape in which the portion where the solder resist 6a in the vicinity (between) the electronic components 4 is removed and the portion where the solder resist 6a on the outer peripheral portion of the electronic component built-in module is removed are connected. Yes.

  Depending on the arrangement of the electronic component 4, the portion from which the solder resist 6 a has been removed may not be connected, and may have to be made into individual shapes. However, it is desirable that the portion from which the solder resist 6a is removed, that is, the solder resist removed portion 17c is as many as possible.

  As described above, in Embodiment 2 of the present invention, by removing the solder resist in the vicinity (between) the electronic components, the insulating resin has a surface layer (upper surface) of the wiring board having higher adhesion than the solder resist. When the module with built-in circuit components is mounted on the mother board of an electronic device, the module is built into the module with built-in electronic components. It is possible to prevent generation of a gap between the insulating resin and the wiring board caused by rapid volume expansion due to the included water vaporization.

  In addition, by providing many removal parts from which the solder resist has been removed, the adhesion strength of the entire electronic component built-in module can be increased, and the solder resist in the vicinity (between) the electronic components on the wiring board has been removed. By connecting the removed part and the removed part from which the solder resist on the outer periphery of the wiring board is removed, not only the adhesion strength of the entire electronic component built-in module is increased, but also from the interface between the insulating resin and the wiring board. By preventing the moisture or moisture from penetrating, the remelted solder can be prevented from flowing out of the predetermined electrode.

  The module with a built-in electronic component according to the present invention has excellent adhesion and connectivity in the module configuration, and has an effect that enables reliable and highly reliable assembly and mounting on an electronic device. It is useful for applications such as electronic component built-in modules and small electronic circuit blocks that are mounted on and mounted with insulating resin.

Overview sectional drawing of the electronic component built-in module in embodiment of this invention Outline plan view of the wiring board Outline top view of the wiring board containing the same number of electronic components Outline sectional view of electronic component built-in module in other embodiment Outline plan view of the wiring board Outline top view of the wiring board containing the same number of electronic components Overview of conventional electronic component built-in module

Explanation of symbols

1,2,31 Electronic component built-in module 2,22 Wiring board 3,3a, 23 Electrode 4,24 Electronic component 5,25 Solder 6,6a, 16,26 Solder resist 7,27 Insulating resin 10 Inner via 11,12, 20 Wiring pattern 13 Back electrode 14, 28 Solder terminal 15, 29 Shield layer 17, 17a, 17b, 17c Removal part

Claims (14)

At least one or more electronic components, an electrode for mounting the electronic component on a surface layer and a solder resist, a wiring substrate having at least one wiring layer, and the electronic component as an electrode of the wiring substrate In the electronic component built-in module in which these are bonded with solder and covered with insulating resin, part or all of the solder resist on the outer peripheral portion of the wiring board is removed, and the insulating resin is bonded directly to the removed portion. An electronic component built-in module characterized by being filled. At least one or more electronic components, an electrode for mounting the electronic component on a surface layer and a solder resist, a wiring substrate having at least one wiring layer, and the electronic component as an electrode of the wiring substrate In the electronic component built-in module in which these are bonded with solder and covered with insulating resin, a part of the solder resist near the mounted electronic component on the wiring board is removed, and the insulating resin is bonded directly to the removed portion. The electronic component built-in module is characterized by being filled as described above. 3. The electronic component built-in module according to claim 1, wherein a shield layer made of metal plating is provided on the surface layer of the insulating resin. 4. The electronic component built-in according to claim 1, wherein a solder resist removal portion in the vicinity of the electronic component on the wiring board is connected to a solder resist removal portion on the outer peripheral portion. module. 4. The electronic component built-in module according to claim 1, wherein a part of the solder resist in the vicinity of the plurality of electronic components is removed and the removed portions are connected. 6. The electronic component built-in module according to claim 1, wherein a plurality of removed portions are formed by removing a part of the solder resist near the electronic component. The electronic component built-in module according to claim 1, wherein an electronic component is mounted on the wiring board and mounted, and O ₂ ashing is performed before the electronic component is covered with an insulating resin. The electronic component built-in module according to any one of claims 1 to 6, wherein an electronic component is mounted on the wiring board and mounted, and a silane coupling agent coating treatment is performed before the electronic component is covered with an insulating resin. . The electronic component is mounted on a wiring board and mounted, and O ₂ ashing treatment and silane coupling agent coating treatment are performed before the electronic component is covered with an insulating resin. Module with built-in electronic components. The solder resist removed portion of the wiring board, or the wiring pattern exposed in the removed portion is covered with an insulating resin after being subjected to a cloth or roughening, according to any one of claims 1 to 6 The electronic component built-in module described. 7. The electronic component built-in module according to claim 1, wherein the wiring board has a water absorption rate of 0.3% or less under standing conditions of 60 ° C., 60%, and 20H. The electronic component built-in module according to any one of claims 1 to 11, wherein the insulating resin is a mixture of an inorganic filler and a thermosetting resin. 12. The electronic component built-in module according to claim 1, wherein an expansion coefficient of the insulating resin is 30 ppm or less. The electronic component built-in module according to claim 1, wherein the insulating resin has a flexural modulus of 20 Gpa or less.

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