JP2013247236A - Component built-in substrate and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a void while thinning a substrate.SOLUTION: In a component built-in substrate, first to fourth printed wiring base materials 10-40 on which wiring patterns and vias are formed are laminated on an insulation base material, and an electronic component 90 is built in an opening 29 of the second printed wiring base material 20. The component built-in substrate manufacturing method is performed as follows. First, protection layers 92 are formed on an electrode formation face 9a and an opposite side face 9b of the electronic component 90 via an adhesive layer 9b. Next, an adhesive layer 9a is formed on one face of the first printed wiring base material 10. Then, the protection layers 92 and the adhesive layer 9a are opposed to each other, so as to crimp the electronic component 90 and the first printed wiring base material 10.

Description

  The present invention relates to a component-embedded substrate that incorporates an electronic component and a method for manufacturing the same.

  In recent years, mobile phones and the like have become more sophisticated and lower in cost, and further improvements have been required for electronic components and wiring boards provided therein. Therefore, various attempts have been made to achieve thinning of the wiring board and simplification of the manufacturing method (see Patent Document 1).

  In order to realize high-density mounting of electronic components, a component-embedded substrate in which electronic components are embedded in a wiring substrate is known. In the manufacturing process of such a component built-in substrate, an adhesive is attached to the wiring substrate and the electronic component. Next, an electronic component is put into a cavity (opening) formed in the wiring board, and the wiring board and the electronic component are pressure-bonded. Thereby, the adhesive material flows into the clearance (gap) between the cavity and the electronic component.

JP 2001-119148 A

  However, if the amount of the adhesive is reduced in order to reduce the thickness of the component-embedded substrate, the amount of the adhesive flowing into the clearance portion also decreases, and there is a problem that a void is formed in the clearance portion.

  An object of the present invention is to provide a method for manufacturing a component-embedded substrate that eliminates the above-described problems caused by the prior art and can reduce the thickness and suppress the generation of voids.

  A method for manufacturing a component-embedded substrate according to the present invention is a method for manufacturing a component-embedded substrate, in which a plurality of printed wiring substrates each having a wiring pattern formed on an insulating substrate are stacked and an electronic component is embedded. Forming a first adhesive layer on a surface of the component opposite to the electrode forming surface and covering the first adhesive layer with a protective layer; and forming a second adhesive layer on at least one surface of the printed wiring substrate. And a step of pressing the electronic component and the printed wiring substrate so that the protective layer and the second adhesive layer are opposed to each other.

  According to the method for manufacturing a component-embedded substrate according to the present invention, when the electronic component and the printed wiring substrate are pressure-bonded, pressure is applied to the first and second adhesive layers existing between them. And the second adhesive layer flows out along the protective layer. Thereby, since the 1st and 2nd adhesive layers enter into a clearance part appropriately, generation | occurrence | production of a void can be suppressed while reducing in thickness. Further, when the first adhesive layer is formed on the electronic component, the first adhesive layer is covered with the protective layer, so that the handling when the electronic component and the printed wiring substrate are pressure-bonded and laminated is also good.

  In one embodiment of the method for manufacturing a component-embedded substrate, the protective layer has a melting point higher than a pressure bonding temperature in a step of pressure bonding the electronic component and the printed wiring board. Thereby, a protective layer does not melt out in a press-bonding process, and the physical properties of the first and second adhesive layers do not change.

  The component-embedded substrate according to the present invention is a component-embedded substrate manufactured by the above-described manufacturing method according to the present invention.

  According to the component-embedded substrate according to the present invention, the electronic component and the printed wiring board are pressure-bonded by the first and second adhesive layers via the protective layer. Therefore, the adhesive can be efficiently poured into the clearance, and the first and second adhesive layers can stably adhere the electronic component and the printed wiring board without changing the physical properties. .

  According to the present invention, it is possible to reduce the thickness and suppress the generation of voids.

It is sectional drawing which shows the structure of the component built-in board | substrate which concerns on embodiment of this invention. It is a flowchart which shows the manufacturing process of the same component built-in board. It is a flowchart which shows the manufacturing process of the same component built-in board. It is a flowchart which shows the manufacturing process of the same component built-in board. It is a flowchart which shows the manufacturing process of the same component built-in board. It is a flowchart which shows the manufacturing process of the same component built-in board. It is sectional drawing which shows the same component built-in board | substrate for every manufacturing process. It is sectional drawing which shows the same component built-in board | substrate for every manufacturing process. It is sectional drawing which shows the same component built-in board | substrate for every manufacturing process.

  Hereinafter, a component-embedded substrate and a manufacturing method thereof according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing the structure of a component-embedded substrate according to an embodiment of the present invention. As shown in FIG. 1, the component-embedded substrate according to the embodiment includes a first printed wiring substrate 10, a second printed wiring substrate 20, a third printed wiring substrate 30, and a fourth printed wiring substrate 40. Are laminated together by thermocompression bonding (adhesive layers 9a to 9d). The adhesive layers 9 a and 9 b adhere between the first printed wiring substrate 10 and the second printed wiring substrate 20. The adhesive layer 9c adheres between the second printed wiring base material 20 and the third printed wiring base material 30, and the adhesive layer 9d is between the third printed wiring base material 30 and the fourth printed wiring base material 40. Glue. The adhesive layers 9a to 9d are made of, for example, an organic adhesive containing a volatile component, such as an epoxy adhesive or an acrylic adhesive.

  Further, the component-embedded substrate is embedded in the opening 29 formed in the second resin substrate 21 of the second printed wiring substrate 20 while being sandwiched between the first and third printed wiring substrates 10 and 30. The electronic component 90 is provided. A clearance 50 (gap) exists between the opening 29 and the electronic component 90. The clearance portion 50 is filled with the adhesive layers 9a and 9b by suppressing the generation of voids by using a manufacturing process described later.

  The 1st-4th printed wiring base materials 10-40 are the 1st resin base material 11, the 2nd resin base material 21, the 3rd resin base material 31, and the 4th resin base material 41, respectively, these 1st-4th. Signal wirings 12, 22, 32, and 42 formed on at least one surface of the resin base materials 11 to 41 are provided. In addition, the first to fourth printed wiring substrates 10 to 40 are signal vias 14 and 34 that are filled in via holes formed in the first, third, and fourth resin substrates 11, 31, and 41, respectively. , 44 and a signal via 24 formed so as to conduct both surfaces of the second resin substrate 21 in a via hole formed in the second resin substrate 21. The signal via 14 electrically connects the signal wirings 12 and 22, the signal via 34 electrically connects the signal wirings 22 and 32, and the signal via 44 connects between the signal wirings 32 and 42. Are electrically connected.

  Further, the first and fourth printed wiring base materials 10 and 40 are respectively formed on the first resin base material 11 and the fourth resin base material 41 at portions where the signal wirings 12 and 42 are not formed. 48.

  As the first to fourth printed wiring substrates 10 to 40, for example, a single-sided copper-clad laminate (single-sided CCL), a double-sided copper-clad laminate (double-sided CCL), or the like can be used. In this example, the second printed wiring board 20 is formed based on the double-sided CCL, and the other is formed based on the single-sided CCL. Accordingly, the signal wiring 22 of the second printed wiring substrate 20 is formed on both surfaces of the second resin substrate 21, and the signal via 24 connects the signal wirings 22 on both surfaces with each other.

  The 1st-4th resin base materials 11-41 are each comprised by the resin film about 25 micrometers thick, for example. Here, as the resin film, for example, a resin film made of thermoplastic polyimide, polyolefin, liquid crystal polymer, or the like, or a resin film made of a thermosetting epoxy resin can be used.

  The signal wirings 12, 22, 32, and 42 are formed by patterning a conductive material such as copper foil. The signal vias 14, 34, and 44 are each made of a conductive paste filled in the via holes, and the signal via 24 is formed by plating.

  The conductive paste is, for example, at least one kind of low electrical resistance metal particles selected from nickel, gold, silver, copper, aluminum, iron and the like, and at least one kind selected from tin, bismuth, indium, lead and the like. And a metal paste having a melting point and a paste in which a binder component mainly composed of epoxy, acrylic, urethane or the like is mixed.

  The conductive paste thus configured has a characteristic that the contained low melting point metal can be melted at 200 ° C. or less to form an alloy, and in particular, can form an intermetallic compound with copper or silver. Prepare. Note that the conductive paste can also be formed of a nanopaste in which fillers such as gold, silver, copper, and nickel having a nanometer particle size are mixed with the binder component as described above.

  In addition, the conductive paste can also be composed of a paste in which metal particles such as nickel are mixed with the binder component as described above. In this case, the conductive paste has a characteristic that electrical connection is made when metal particles come into contact with each other. As a method for filling the via holes with the conductive paste, for example, a printing method, a spin coating method, a spray coating method, a dispensing method, a laminating method, and a method using these in combination can be used.

  The electronic component 90 is configured by WLP (Wafer Level Package). As shown in FIG. 1, an electrode 91 </ b> B is provided on the electrode formation surface 91 b of the electronic component 90. An adhesive layer 9b is provided on the back surface 91a opposite to the electrode forming surface 91b of the electronic component 90, and a protective layer 92 is provided on the surface of the adhesive layer 9a. The electronic component 90 and the first printed wiring substrate 10 are pressure-bonded so that the protective layer 92 and the adhesive layer 9a provided on the surface of the first printed wiring substrate 10 are opposed to each other.

  Here, said protective layer 92 has melting | fusing point higher than the temperature in the process of crimping | bonding the 1st-4th printed wiring base materials 10-40 and the electronic component 90 which are mentioned later. For example, the protective layer 92 may be a substance having a melting point of 250 ° C. or higher, and is composed of a metal foil (copper, aluminum, etc.) or an insulating layer (PET, polyimide, liquid crystal polymer, etc.). The protective layer 92 may be a laminate of a metal foil and an insulating layer.

  Next, a method for manufacturing the component-embedded substrate according to the embodiment will be described. 2 to 5 are flowcharts showing manufacturing steps of the component built-in substrate. 6 to 9 are cross-sectional views showing the component-embedded substrate for each manufacturing process. 2 and 6 show the manufacturing process of the third printed wiring substrate 30, and FIGS. 3 and 7 show the manufacturing process of the second printed wiring substrate 20. 4 and 8 show the manufacturing process of the electronic component 90, and FIGS. 5 and 9 show the final process of the manufacturing process of the component built-in substrate.

  First, the manufacturing process of the 1st, 3rd and 4th printed wiring base materials 10, 30, and 40 is demonstrated. Since these can be manufactured in the same process, here, the manufacturing process of the third printed wiring substrate 30 will be described as a representative with reference to FIG. 2, but the first and fourth printed wiring substrates will be described. The same applies to 10, 40.

  As shown in FIG. 6A, a single-sided copper-clad laminate (single-sided CCL) in which the conductor layer 8 is formed on one surface of the third resin base material 31 is prepared (step S100). Next, after forming an etching resist on the conductor layer 8 by photolithography, etching is performed to form a wiring pattern such as the signal wiring 32 as shown in FIG. 6B (step S102).

  When the wiring pattern is formed, as shown in FIG. 6C, the adhesive layer 9c is attached to the surface of the third resin base 31 opposite to the signal wiring 32 forming surface by thermocompression bonding (step S104). . Then, as shown in FIG. 6D, the via hole 6 penetrating the adhesive layer 9c and the third resin base material 31 toward the signal wiring 32 is formed at a predetermined location (step S106), and plasma is formed in the via hole 6. Apply desmear treatment.

  Finally, as shown in FIG. 6E, the signal via 34 is formed by filling the formed via hole 6 with a conductive paste, for example, by screen printing (step S108), and the signal wiring 32 and the signal via. 34, the third printed wiring board 30 having the third resin base 31 provided with the adhesive layer 9c is formed. By performing such a process, the first and fourth printed wiring substrates 10 and 40, and in the case of a multilayer, other printed wiring substrates are formed and prepared. The first and fourth printed wiring substrates 10 and 40 are provided with adhesive layers 9a and 9d.

  Next, the manufacturing process of the second printed wiring board 20 will be described with reference to FIG. In addition, the part already demonstrated may attach | subject the same code | symbol, and may omit description, and suppose that the content mentioned above is applicable to the specific processing content of each step. First, as shown in FIG. 7A, a double-sided copper-clad laminate (double-sided CCL) in which the conductor layer 8 is formed on both sides of the second resin base material 21 is prepared (step S110), and FIG. As shown in FIG. 5, via holes 6 are formed at predetermined locations (step S112), and plasma desmear processing is performed.

  Next, as shown in FIG. 7C, panel plating is performed on the entire surface of the second resin base material 21 (step S114), and a plating layer is formed on the conductor layer 8 in which the via hole 6 is formed and in the via hole 6. 23 is formed. The plating layer 23 is later used as a signal via 24 and electrically connects the conductor layers 8 on both surfaces of the second resin base material 21.

  Then, as shown in FIG. 7D, the plating layer 23 and the conductor layer 8 on the second resin base material 21 are etched to form wiring patterns such as the signal wiring 22 and the signal via 24. (Step S116). Finally, as shown in FIG. 7 (e), the second resin base material 21 where the electronic component 90 is embedded is removed by a UV laser or the like to form an opening 29 (step S118), and the second The printed wiring board 20 is formed.

  Next, the manufacturing process of the electronic component 90 will be described with reference to FIG. First, as shown in FIG. 8A, a wafer 94 is prepared, and an electrode 91B having a predetermined pattern is formed on one surface of the wafer 94 (step S120). Next, as shown in FIG. 8B, a protective layer 92 is formed on the other surface of the wafer 94 via the adhesive layer 9b (step S122). Subsequently, as shown in FIG. 8C, the electronic component 90 is produced by dicing into pieces (step S124).

  The process of step S122 in FIG. 4 is performed by sticking a film composed of the adhesive layer 9b and the protective layer 92 to the other surface of the wafer 94. Further, the process of step S122 may be executed by the following process. That is, first, a film composed of the adhesive layer 9 b and the protective layer 92 is attached to the other surface of the wafer 94. Next, the protective layer 92 is peeled off from the film, and a new protective layer is attached to the other surface of the wafer 94 via the adhesive layer 9b.

  If the 1st-4th printed wiring base materials 10-40 and the electronic component 90 are produced as mentioned above, the manufacturing process of step S130, S132 shown in FIG. 5 will be performed. That is, first, as shown in FIG. 9, each printed wiring board 10-40 and the electronic component 90 are positioned and laminated (step S130). Here, the electronic component 90 is inserted into the opening 29 of the second printed wiring board 20, and a clearance 50 is generated between the opening 29 and the electronic component 90.

  Next, for example, using a vacuum press machine, heat lamination is performed by heating and pressurizing in a reduced pressure atmosphere of 1 kPa or less (step S132), and a component built-in substrate as shown in FIG. 1 is manufactured. At this time, the conductive paste filled in the via hole 6 is cured and alloyed simultaneously with the curing of the adhesive layers 9a to 9d between the layers, the resin base materials 21 and 31, and the like.

  In the steps shown in FIGS. 5 and 9, when the electronic component 90 and the first printed wiring substrate 10 are pressure-bonded, the pressure applied to the protective layer 92 causes the adhesive layers 9a and 9b to be cleared with the protective layer 92 as a boundary. The adhesive layers 9a and 9b appropriately enter the clearance portion 50. Therefore, this embodiment can suppress the generation of voids in the clearance portion 50 and can be thinned.

  Moreover, since the protective layer 92 has a melting point higher than the temperature in the pressure bonding step (step S132), it does not melt in step S132. Therefore, the physical properties of the adhesive layers 9a and 9b do not change.

  DESCRIPTION OF SYMBOLS 6 ... Via hole, 8 ... Conductor layer, 9a-9d ... Adhesion layer, 10-40 ... 1st-4th printed wiring base material, 11-41 ... 1st-4th resin base material, 12-42 ... 1st-1st 4th signal wiring, 14 to 44 ... 1st to 4th signal via, 18, 48 ... Solder resist, 23 ... Plating layer, 29 ... Opening, 50 ... Clearance part, 90 ... Electronic component, 91B ... Electrode, 91a ... back surface, 91b ... electrode formation surface, 92 ... protective layer, 94 ... wafer.

Claims (3)

A method of manufacturing a component-embedded substrate in which a plurality of printed wiring substrates having a wiring pattern formed on an insulating substrate are laminated and an electronic component is built in an opening formed in the printed wiring substrate,
Forming a first adhesive layer on a surface opposite to the electrode forming surface of the electronic component and covering the first adhesive layer with a protective layer;
Forming a second adhesive layer on at least one surface of the printed wiring board;
And a step of crimping the electronic component and the printed wiring substrate so that the protective layer and the second adhesive layer are opposed to each other. The method for manufacturing a component built-in substrate according to claim 1, wherein the protective layer has a melting point higher than a pressure bonding temperature in a step of pressure bonding the electronic component and the printed wiring substrate. A component-embedded substrate manufactured by the manufacturing method according to claim 1.

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