JP5311162B1 - Manufacturing method of component mounting board - Google Patents

Abstract

A reflow process and an underfill process are not required, a temperature load on an electronic component and a substrate is reduced, connection stability of a mounting portion is improved, and connection reliability of the substrate is increased.
A component mounting board 1 includes an adhesive layer 41 formed on a surface layer of the substrate, and component mounting portions 42 and 43 formed on the adhesive layer 41 and having openings for mounting electronic components 110 and 120. A film material 40, a conductive paste via 44 filled in via openings 45 on the wirings 12 a and 12 b of the substrate in the adhesive layer 41, and a film so that the electrodes 111 and 121 are connected to the conductive paste via 44. Electronic components 110 and 120 mounted on the adhesive layer 41 in the component mounting portions 42 and 43 of the material 40, and the electrodes 111 and 121 of the electronic components 110 and 120 and the conductive paste vias 44 are directly connected. Yes.
[Selection] Figure 1

Description

  The present invention relates to a component mounting board on which electronic components are surface-mounted, a manufacturing method thereof, and a component mounting board mounting body.

  Generally, a solder material is used for mounting electronic components on a substrate (see, for example, Patent Document 1). In recent years, lead (Pb) -free type solder has become mainstream in consideration of the environment, but usually solder has high connection reliability, but has a high melting point of 200 ° C or higher, and remelts when reheated. It is necessary to use it in consideration of what to do.

JP 2010-10671 A

  However, when using the current solder, there is a problem in that the temperature change during solder connection, reflow, underfill, etc. is large with respect to component mounting, and the temperature load on the electronic component and the substrate is large. In particular, if there is a defect such as a void in the resin after underfill, there is a problem that the remelted solder flows during reflow of the secondary mounting, which may lead to damage of the mounting portion.

  The present invention eliminates the problems caused by the prior art described above, eliminates the need for a reflow process and an underfill process, reduces the temperature load on the electronic components and the board, improves the connection stability of the mounting part, and improves the connection reliability of the board. An object of the present invention is to provide a component mounting board, a method of manufacturing the same, and a component mounting board mounting body that can improve the performance.

  A method for manufacturing a component mounting board according to the present invention is a method for manufacturing a component mounting board, in which a plurality of printed wiring boards each having a wiring pattern including wiring pads and vias formed on a resin base material are stacked and electronic components are surface-mounted. A step of forming a plurality of printed wiring boards by forming at least one of the wiring patterns and vias on a plurality of resin base materials, and a surface of the printed wiring board serving as a surface layer on the wiring pads. Forming an adhesive layer having via openings formed therein, filling the via openings in the adhesive layer with a conductive paste to form conductive paste vias, and connecting electrodes directly to the conductive paste vias A step of mounting the electronic component on the adhesive layer, and arranging a plurality of the printed wiring boards by arranging auxiliary materials on the printed wiring board on which the electronic components are mounted. 200 ° C. and thermocompression bonding at a temperature below characterized by comprising the step of batch lamination.

  According to the method for manufacturing a component mounting board according to the present invention, the same effects as the above component mounting board can be obtained, and thermocompression bonding is performed at a temperature of 200 ° C. or lower, so that the temperature is applied to the electronic component and the board. Can be reduced.

  According to the present invention, the reflow process and the underfill process are unnecessary, the temperature load on the electronic component and the substrate is reduced, the connection stability of the mounting portion is improved, and the connection reliability of the substrate can be increased.

It is sectional drawing which shows the component mounting board which concerns on one Embodiment of this invention. It is a flowchart which shows the manufacturing process by the manufacturing method of the component mounting board | substrate. It is a flowchart which shows the manufacturing process by the manufacturing method of the component mounting board | substrate. It is sectional drawing which shows the said component mounting board | substrate for every manufacturing process. It is sectional drawing which shows the said component mounting board | substrate for every manufacturing process. It is sectional drawing which shows the said component mounting board | substrate for every manufacturing process. It is sectional drawing which shows the said component mounting board | substrate for every manufacturing process. It is sectional drawing which shows the component mounting board | substrate mounting body which concerns on one Embodiment of this invention.

  Hereinafter, a component mounting board, a manufacturing method thereof, and a component mounting board mounting body 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 a component mounting board according to an embodiment of the present invention. As shown in FIG. 1, the component mounting board 1 includes a first printed wiring board 10, a second printed wiring board 20, and a third printed wiring board 30.

  The component mounting board 1 includes a plurality of electronic components 110 and 120 mounted on the first printed wiring board 10 on the surface layer. The component mounting board 1 has a structure in which first to third printed wiring boards 10 to 30 and electronic components 110 and 120 are collectively laminated by thermocompression bonding. In the electronic components 110 and 120, the electrodes 111 and 121 are electrically conductive in the component mounting portions 42 and 43 formed of openings formed in the film material 40 disposed on the surface of the first printed wiring board 10 via the adhesive layer 41. It is mounted on the adhesive layer 41 in a state of being directly connected to the conductive paste via 44.

  The first, second, and third printed wiring boards 10, 20, and 30 are respectively the first, second, and third resin base materials 11, 21, 31, and the first to third resin base materials 11-31. Wirings 12a, 12b, 22, and 32 formed on at least one side, and an interlayer connection via 13 made of a conductive paste filled in, for example, the via holes 2 formed in the first and second resin base materials 11 and 21. , 23. These 1st-3rd printed wiring boards 10-30 can be comprised by single-sided CCL and double-sided CCL.

  The 1st-3rd resin base materials 11-31 are each comprised by the resin film about 25 micrometers thick, for example. As the resin film, for example, polyimide, polyolefin, liquid crystal polymer (LCP), or the like can be used. The wirings 12a, 12b, 22, 32 are made of, for example, a patterned copper foil. The illustrated portions of the wirings 12 a and 12 b of the first printed wiring board 10 function as wiring pads that are electrically connected to the electrodes 111 and 121 of the electronic components 110 and 120.

  The electronic component 110 is made of a semiconductor element such as a transistor, an integrated circuit (IC), or a diode. The electronic component 120 includes a resistor, a capacitor, a relay, a piezoelectric element, and the like. The electronic component 110 shown in FIG. 1 is, for example, a WLP (Wafer Level Package) subjected to rewiring. A plurality of electrodes (redistribution electrodes) 111 formed on the pads 111c are provided on the electrode formation surface 111b of the electronic component 110, and an insulating layer 111d is formed around the electrodes.

  The interlayer connection vias 13 and 23 and the conductive paste via 44 are made of conductive paste filled in the via holes 45 formed in the via holes 2 and the wirings 12a and 12b of the adhesive layer 41, respectively. 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. Low melting point metal particles. The conductive paste is made of a paste obtained by mixing these metal particles with a binder component mainly composed of epoxy, acrylic, urethane, or the like.

  The conductive paste thus configured has the ability to form an alloy by melting the contained low melting point metal at 200 ° C. or less, and in particular, can form an intermetallic compound with copper or silver. Is provided. Therefore, the connection portion between each via and the wiring is alloyed by the intermetallic compound at the time of thermocompression bonding of the batch lamination.

  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 first to third printed wiring boards 10 to 30 and the film material 40 are laminated via the adhesive layer 9 and the adhesive layer 41. The adhesive layers 9 and 41 are made of, for example, a thermosetting resin.

Next, a method for manufacturing the component mounting board 1 according to the present embodiment will be described.
FIG. 2A and FIG. 2B are flowcharts showing a manufacturing process according to a method for manufacturing a component mounting board. 3 to 6 are cross-sectional views showing the component mounting board for each manufacturing process. Note that the second and third printed wiring boards 20 and 30 can be manufactured in the same process as the manufacturing process of the first printed wiring board 10, and therefore the description thereof is omitted here unless otherwise specified.

  First, the manufacturing process of the 1st printed wiring board 10 is demonstrated, referring FIG. 2A. As shown in FIG. 3A, a single-sided CCL in which a conductor layer 12c made of a solid copper foil or the like is formed on one surface of the first resin substrate 11 is prepared (step S100). Next, after forming an etching resist on the conductor layer 12c by photolithography, etching is performed to form wiring patterns such as wirings 12a and 12b as shown in FIG. 3B (step S102).

  The single-sided CCL used in step S100 has a structure in which a first resin base material 11 having a thickness of about 25 μm is bonded to a conductor layer 12c made of, for example, a copper foil having a thickness of about 12 μm. As this single-sided CCL, for example, a material produced by applying a polyimide varnish to a copper foil and curing the varnish by a known casting method can be used.

  In addition, as single-sided CCL, a seed layer is formed on a polyimide film by sputtering and copper is grown by plating to form a conductor layer 12c, or a rolled or electrolytic copper foil and a polyimide film are bonded together with an adhesive. It is also possible to use the one produced by the above.

  Note that the first resin base 11 does not necessarily need to be made of polyimide, and may be made of a plastic film such as a liquid crystal polymer as described above. In addition, an etchant mainly composed of ferric chloride or cupric chloride can be used for the etching in step S102.

  When the wiring pattern is formed, as shown in FIG. 3C, the adhesive 9a is attached to the surface of the first resin substrate 11 opposite to the wiring 12a, 12b formation side by thermocompression bonding (step S104). . For example, an epoxy thermosetting film having a thickness of about 25 μm can be used as the adhesive material 9a attached in step S104. For thermocompression bonding, a vacuum laminator is used, and the adhesive 9a is pressed under a pressure of 0.3 MPa at a temperature at which the adhesive 9a is not cured in a reduced pressure atmosphere.

  The interlayer adhesive used for the adhesive layer 9 and the adhesive 9a is not only an epoxy thermosetting resin, but also an acrylic adhesive, a thermoplastic adhesive represented by thermoplastic polyimide, and the like. It is done. Further, the interlayer adhesive does not necessarily need to be in the form of a film, and may be obtained by applying a varnish-like resin. The same applies to the adhesive layer 41.

  Then, as shown in FIG. 3D, laser light is irradiated from, for example, the bonded material 9a side toward the wiring 12a using, for example, a UV-YAG laser device, and the adhesive 9a and the first material The via hole 2 penetrating the resin base material 11 is formed at a predetermined location (step S106). The formed via hole 2 is subjected to, for example, a plasma desmear process after the formation.

In addition, the via hole 2 formed in step S106 may be formed by a carbon dioxide laser (CO ₂ laser), an excimer laser, or the like, or may be formed by drilling or chemical etching. The desmear treatment can be performed with a mixed gas of CF ₄ and O ₂ (tetrafluoromethane + oxygen), but other inert gas such as Ar (argon) can also be used. Alternatively, wet desmear treatment using a chemical solution may be used.

  When the via hole 2 is formed, as shown in FIG. 3E, the via hole for interlayer connection 13 is formed by filling the formed via hole 2 with the conductive paste as described above by, for example, screen printing or the like (step S108). ), The first printed wiring board 10 having the first resin base material 11 provided with the adhesive layer 9 is manufactured. The second and third printed wiring boards 20 and 30 can be manufactured in the same manner. In the case of a multilayer structure, other printed wiring boards may be formed and prepared.

  When the first to third printed wiring boards 10 to 30 are manufactured in this way, as shown in FIG. 2B and FIG. 4A, the interlayer connection vias 13 and 23 and the wirings 22 and 32 are connected by an electronic component mounting machine. Each printed wiring board 10-30 is positioned in a state in which the conductive paste of each adhesive layer 9 and interlayer connection vias 13 and 23 is not cured, as shown in FIG. (Step S120).

  Next, as shown in FIG. 5A, for example, a film having component mounting portions 42 and 43 in which mounting positions of electronic components 110 and 120 corresponding to the wirings 12a and 12b of the first printed wiring board 10 are opened in advance. The material 40 is disposed on the surface of the first printed wiring board 10 via the adhesive layer 41 (step S122).

  Then, as shown in FIG. 5B, the via opening 45 is formed by irradiating the laser beam on the wirings 12a and 12b in the adhesive layer 41 on the first printed wiring board 10 as described above (step S124). 5C, a conductive paste via 44 is formed by filling the formed via opening 45 with a conductive paste by screen printing or the like (step S126).

  When the conductive paste 44 is formed in this way, as shown in FIG. 5D, the electronic components 110 and 120 are arranged on the component mounting portions 42 and 43, and the electrodes 111 and 121 and the conductive paste via 44 are thermocompression bonded. The electronic components 110 and 120 are mounted on the adhesive layer 41 in the component mounting portions 42 and 43 of the film material 40 so that they are sometimes connected (step S128). In the state shown in the drawing, the electrode 111 of the electronic component 110 is not in contact with the conductive paste via 44, but the conductive paste via 44 may be formed so as to be in contact with the mounting on the adhesive layer 41.

  Thereafter, as shown in FIG. 6A, the first print is performed on the first printed wiring board 10 on which the electronic components 110 and 120 are mounted (that is, on the film material 40 and the electronic components 110 and 120) with pressure or temperature. A secondary material 50 made of a thermoplastic resin or the like that can be deformed into the surface shape of the wiring board 10 is disposed (step S130).

  Finally, as shown in FIG. 6 (b), each printed wiring board 10-30 together with the auxiliary material 50 as shown by a white arrow in a reduced pressure atmosphere of 1 kPa or less using, for example, a vacuum press machine. Is heated and pressed at a temperature of 200 ° C. or less, and is laminated by thermocompression bonding (step S132), the auxiliary material 50 is removed (step S134), and the component mounting board 1 as shown in FIG. To manufacture. The secondary material 50 may be formed sufficiently thicker than the thickness of the electronic components 110 and 120, and the contact surface with the component mounting substrate 1 may be subjected to an easy mold release process coated with, for example, a fluororesin.

  At the time of batch lamination, the interlayer connection vias 13 and 23 filled in the via holes 2 and the via openings 45 and the conductive layers are simultaneously formed with the curing of the adhesive layers 9 between the layers, the adhesive layer 41 on the surface layer, and the resin base materials 11 to 31. Curing and alloying of the conductive paste of the paste via 44 is performed. Accordingly, an intermetallic compound alloy layer as described above is formed between the wirings 12a, 12b, 22, 32 and the electrodes 111, 121 in contact with the conductive paste.

  In the component mounting board 1 configured in this way, the conductive paste via 44 is used to connect the electrodes 111 and 121 of the electronic components 110 and 120 to the board, so that the solder material in the reflow process after component mounting is used. Remelting does not occur. In addition, since the electronic components 110 and 120 are thermocompression bonded after the conductive paste is filled in the via openings 45 formed in the adhesive layer 41, vias and underfills for connecting components can be formed at a time.

  In addition, since it is not necessary to consider underfill filling formation, the opening dimensions of the component mounting portions 42 and 43 can be adjusted to the outer dimensions of the electronic components 110 and 120, and the gap between the electronic components 110 and 120 can be narrowed. Thus, the overall height of the component mounting board 1 can be suppressed. Furthermore, since the electronic components 110 and 120 are pressurized by the auxiliary material 50, variations in pressurization caused by differences in component height can be alleviated and variations in mechanical strength can be reduced.

  Moreover, since the heating temperature in thermocompression bonding is 200 ° C. or less, it is possible to suppress changes in characteristics of the electronic components 110 and 120, warpage of the printed wiring boards 10 to 30, and residual stress compared to the conventional case. Since the auxiliary material 50 is used in place of the solder resist, not only the manufacturing process is simplified, but also the reflow and underfill processes after component mounting are not required, and the cost can be reduced as compared with the conventional method.

  FIG. 7 is a cross-sectional view showing a component mounting board mounting body according to an embodiment of the present invention. As shown in FIG. 7, the component mounting board mounting body 1 </ b> A is connected to the component mounting board 1 described above, for example, via the interlayer connection via 33 formed in the third printed wiring board 30. The wiring board 60 is added, and the wiring board 60 is mounted on the mounting surface 91 of the mounting substrate 90 via the solder bumps 92.

  The fourth printed wiring board 60 is made of, for example, a double-sided CCL, and has a structure in which the wirings 62 on both sides of the fourth resin base 61 are connected by plating vias. A solder resist 69 is formed on the surface of the mounting substrate 90 on the mounting surface 91 side. The solder bump 92 is formed on the wiring 62 on the solder resist 69 side. Also in the component mounting board mounting body 1A configured as described above, the same operational effects as those of the component mounting board 1 can be obtained.

DESCRIPTION OF SYMBOLS 1 Component mounting board 1A Component mounting board mounting body 2 Via hole 9, 41 Adhesion layer 10 1st printed wiring board 11 1st resin base material 12a, 12b Wiring 13, 23 Via for interlayer connection 20 2nd printed wiring board 21 2nd resin Base material 22 Wiring 30 Third printed wiring board 31 Third resin base material 32 Wiring 40 Film material 42, 43 Component mounting portion 44 Conductive paste via 45 Via opening 110, 120 Electronic component

Claims (1)

A method for manufacturing a component mounting board, wherein a plurality of printed wiring boards each having a wiring pattern and vias formed on a resin base material are laminated and surface-mounting an electronic component,
Forming a plurality of printed wiring boards by forming at least one of the wiring patterns and vias on a plurality of resin substrates; and
Forming a bonding layer having a via opening formed on the wiring pad on the surface of the printed wiring board to be a surface layer;
Filling the via opening in the adhesive layer with a conductive paste to form a conductive paste via;
Mounting the electronic component on the adhesive layer such that an electrode is directly connected to the conductive paste via;
A step of arranging a secondary material on the printed wiring board on which the electronic component is mounted, and thermo-compressing the plurality of printed wiring boards at a temperature of 200 ° C. or less and laminating them at once. Manufacturing method of mounting substrate.

Images