1. Field of the Invention
This invention relates to a component-mounting printed board having an electronic component surface-mounted thereon, and a method of manufacturing the component-mounting printed board.
2. Description of the Related Art
Known as a conventional component-mounting printed board having an electronic component mounted on a surface thereof is the component-mounting printed board disclosed in Unexamined Japanese Patent Application Publication No. JP 2011-44512 A (Document 1). In this semiconductor component, a solder bump formed on an electrode of an electronic component is joined to an electrode pad formed on a component-mounting surface of a wiring board, thereby securing electrical conduction of the two. Moreover, a solder bump is formed also on an electrode pad formed on a surface on an opposite side to the component-mounting surface of the wiring board, whereby connection is made to a mounting board such as a mother board, or the like. The electrode pads of each of the surfaces are connected via an interlayer-connecting conductor and an inner layer wiring.
However, in mounting technology such as a BGA system where an electronic component and a wiring board are connected via the likes of a solder bump as in the above-described component-mounting printed board disclosed in Document 1, a diameter of the solder bump attains a size of about 100 μm, hence there is a problem that thinning of the wiring board overall is difficult to achieve. In addition, a formation pitch of the solder bump is also limited due to the size of the solder bump itself, hence there is also a problem that narrowing of pitch of the electrode pad is difficult to achieve, and mounting by high density wiring is difficult.
This invention has an object of solving the above-mentioned problems due to conventional technology to provide a component-mounting printed board capable of being thinned and capable of high density mounting, and a method of manufacturing the component-mounting printed board.
A component-mounting printed board according to the present invention, the component-mounting printed board being a component-mounting printed board having an electronic component surface-mounted thereon, comprises: a resin base; an electronic component mounted on at least one of surfaces of the resin base; and a through-hole electrode formed penetrating the resin base at a position corresponding to an electrode of the electronic component, wherein the electrode of the electronic component and the through-hole electrode are directly joined, and an electrode pad of the through-hole electrode is embedded in the resin base and formed in a surface on an opposite side to a side of a mounting surface on which the electronic component is mounted of the resin base.
As a result of the component-mounting printed board according to the present invention, an electrode of an electronic component mounted on a mounting surface of a resin base and a through-hole electrode formed in the resin base are directly joined, thereby enabling greater thinning and enabling higher density mounting compared to a component-mounting printed board where these are joined via a solder bump. In addition, an electrode pad of the through-hole electrode is embedded in the resin base and formed in a surface on an opposite side to a side of a mounting surface on which the electronic component is mounted of the resin base, thereby enabling greater thinning compared to a component-mounting printed board where the electrode pad is formed on the surface of the resin base.
Note that in an embodiment of the present invention, the electrode of the electronic component is embedded in the resin base. Doing so enables further thinning.
Moreover, another embodiment of the present invention further comprises a circuit formed on the side of the mounting surface on which the electronic component is mounted of the resin base.
Moreover, in yet another embodiment of the present invention, an adhesive layer is formed between an electrode formation surface of the electronic component and the mounting surface of the resin base.
Moreover, in yet another embodiment of the present invention, the adhesive layer is formed only in an underside region of the electronic component.
A method of manufacturing a component-mounting printed board according to the present invention comprises: forming a circuit pattern in a resin base by imprinting, the circuit pattern including a through-hole; aligning an electrode of an electronic component with the through-hole of the circuit pattern to perform alignment, and then mounting the electronic component on the resin base; and filling a conductive paste into the circuit pattern to form in the resin base wiring including a through-hole electrode corresponding to the through-hole and directly join the electrode of the electronic component and the through-hole electrode, and forming an electrode pad of the through-hole electrode being embedded in the resin base in a surface on an opposite side to a side of a mounting surface on which the electronic component is mounted of the resin base.
As a result of the method of manufacturing a component-mounting printed board according to the present invention, a circuit pattern is formed in a resin base by imprinting, an electronic component undergoes alignment and is then mounted on the resin base, and a conductive paste is filled into the circuit pattern to form wiring, hence an electrode of the electronic component and a through-hole electrode can be directly joined and an electrode pad of the through-hole electrode can be embedded in the resin base and formed in a surface on an opposite side to a side of a mounting surface on which the electronic component is mounted of the resin base. As mentioned above, this enables thinning and enables high density mounting.
In an embodiment of the present invention, when mounting the electronic component on the resin base, the electronic component is mounted while the resin base is heated and while a contact surface with the electrode of the electronic component of the resin base is pressurized.
Moreover, in another embodiment of the present invention, an intermetallic compound is formed between the electrode of the electronic component and the conductive paste.
Moreover, in yet another embodiment of the present invention, prior to mounting the electronic component on the resin base, an adhesive layer is formed in a region where the electrode in an electrode formation surface of the electronic component is not formed.
In yet another embodiment of the present invention, the adhesive layer is formed such that a surface thereof is in a state of being more sunken to a side of the electrode formation surface of the electronic component than is an electrode surface of the electrode of the electronic component.
The present invention enables thinning and enables high density mounting.
A component-mounting printed board and a method of manufacturing the same according to embodiments of this invention will be described in detail below with reference to the accompanying drawings.
The resin base 10 is configured by, for example, a resin film having a thickness of about 25 μm. Employable as the resin film are, for example, a resin film configured from the likes of a thermoplastic polyimide, polyolefin, or liquid crystal polymer, or a resin film configured from a thermosetting epoxy resin, and so on.
The electronic component 20 is a semiconductor component such as an IC chip, and has formed on an electrode formation surface 21b thereof facing the mounting surface 10a of the resin base 10 a plurality of mounting-dedicated electrodes 21 each comprising an electrode surface 21a parallel to the electrode formation surface 21b. The through-hole electrode 12 and the rear surface wiring 13 are configured from a conductive paste filled into a concave circuit pattern that includes a through-hole 19 and is formed by impressing irregularities of an imprint mold into the resin base 10.
The conductive paste includes, for example, at least one kind of metallic particle of low electrical resistance selected from the likes of nickel, gold, silver, zinc, aluminum, iron, and tungsten, and at least one kind of metallic particle of low melting point selected from the likes of bismuth, indium, and lead. Moreover, the conductive paste has tin included as a component in these metallic particles, and is configured from a paste having mixed therein a binder component whose main component is an epoxy, an acrylic, a urethane, and so on.
The conductive paste configured in this way enables the tin and the metal of low melting point included therein to melt and form an alloy at a temperature of 200° C. or less, and specifically, the likes of copper or silver comprise characteristics allowing an intermetallic compound to be formed. Note that the conductive paste may also be configured by a nanopaste in which, for example, a filler of the likes of gold, silver, copper, or nickel with a nanolevel particle diameter is mixed into a binder component of the above-described kind. In addition, the conductive paste may also be configured by a paste having metallic particles of the above-described nickel, and so on, mixed into a binder component of the above-described kind. In this case, the conductive paste is characterized in that electrical connection is performed by contact between fellow metallic particles.
The through-hole electrode 12 comprises: an electrode 12a formed on a side of the mounting surface 10a of the resin base 10; and an electrode pad 12b formed on a side of a rear surface 10b on an opposite side to the mounting surface 10a of the resin base 10. The rear surface wiring 13 includes: a wiring main portion 13a formed on the rear surface 10b side of the resin base 10; and an interlayer connector 11 that makes interlayer connection between this wiring main portion 13a and the surface layer circuit 14. Provided on a mounting surface 10a side of the interlayer connector 11 is an electrode 11a connected to the surface layer circuit 14.
The surface layer circuit 14 is configured from a conductive member of copper, or the like, pattern formed on the mounting surface 10a of the resin base 10 after mounting of the electronic component 20, by a system of photolithography, printing, ink jet, or the like. Note that the resin base 10 and the electronic component 20 are connected by an adhesive layer 30 formed between the mounting surface 10a and the electrode formation surface 21b. The adhesive layer 30 is formed by filling an underfill between these mounting surface 10a and electrode formation surface 21b, the underfill being configured from the likes of a composite resin whose main agent is an epoxy system resin.
Note that although omitted from the drawings, the component-mounting printed board 100 may have a solder resist formed therein for protecting the rear surface wiring 13, the adhesive layer 30, the mounting surface 10a or rear surface 10b sides of the resin base 10, and so on. In this case, the solder resist is formed by, for example, a system of photolithography, or the like.
As a result of the component-mounting printed board 100 according to the first embodiment being configured in this way, the electrode 21 of the electronic component 20 and the electrode 12a of the through-hole electrode 12 are directly joined without mediation of a solder bump, or the like. Therefore, thinning of the component-mounting printed board 100 overall can be achieved, and an arrangement pitch of the electrodes 21 and 12a can be narrowed, thereby enabling high density mounting.
In addition, the wiring main portion 13a of the rear surface wiring 13 and the electrode pad 12b of the through-hole electrode 12 are formed in a state of being embedded further inside the resin base 10 than the rear surface 10b of the resin base 10, hence enabling further thinning to be achieved.
Next, a method of manufacturing a component-mounting printed board according to the first embodiment will be described.
First, as shown in
The imprint mold 40 is configured from, for example, a mold manufactured from silicon and including the circuit shaped pattern with a minimum line/space of 5 μm/5 μm and a height of 5 μm. The imprint mold 40 may also be formed by the likes of nickel, copper, and diamond-like carbon (DLC), besides silicon, and may be applied with a mold separation-facilitating processing by having its front surface coated with a fluorine system resin.
Next, as shown in
Then, as shown in
In this step S106, the resin base 10 is configured from a thermoplastic polyimide resin film, hence, for example, the electronic component 20 is mounted after heating to a temperature greater than or equal to a glass-transition point, and cooling is performed after mounting. As a result, a portion of the electrode surface 21a of the electrode 21 is adhered to the mounting surface 10a of the resin base 10, whereby the electronic component 20 can be provisionally adhered to the resin base 10. Note that in the case that the resin base 10 is configured from a thermosetting resin film, a resin hardens due to heating, whereby the two are provisionally adhered.
As shown in
Note that in the above-described step S108, an excess portion of the conductive paste protruding from each of the surfaces 10a and 10b of the resin base 10 are removed by etching, or the like. As a result, the electrode pad 12b of the through-hole electrode 12 and the wiring main portion 13a of the rear surface wiring 13 can be formed in a state of being flat with the rear surface 10b of the resin base 10.
Then, as shown in
The component-mounting printed board 100 according to the first embodiment manufactured in this way allows thinning to be achieved and is capable of high density mounting as mentioned above. Note that the processings of the above-described steps S110 and S112 may be performed having an order thereof reversed. Moreover, the component-mounting printed board 100 may be manufactured as follows.
Next, as shown in
Then, as shown in
Next, as shown in
Note that the component-mounting printed board 100 may have the following structure.
In addition, the component-mounting printed board 100A shown in
As a result, the component-mounting printed board 100C according to the second embodiment has similar working effects to those of the component-mounting printed board 100 according to the first embodiment, and by eliminating a protruding portion of the adhesive layer 30 in the mounting surface 10a of the resin base 10, a mounting area of the electronic component 20 can be reduced, whereby consequently a mounting area on the mounting surface 10a side can be increased.
Next, a method of manufacturing a component-mounting printed board according to the second embodiment will be described.
First, distinct from a main manufacturing process of the component-mounting printed board 100C shown in
The adhesive agent coated or laminated in this step S120 is preferably a liquid form or film form adhesive agent configured from the above-described kind of thermoplastic resin or semi-hardened-state thermosetting resin. Then, as shown in
Then, as shown in
Next, as shown in
Finally, as shown in
Next, as shown in
Finally, as shown in
The component-mounting printed board according to the second embodiment may be manufactured as follows.
Employable as the adhesive agent coated or laminated here is a liquid form or film form adhesive agent configured from the above-described kind of thermoplastic resin or semi-hardened-state thermosetting resin. Then, as shown in
Then, as shown in
Next, as shown in
Finally, as shown in
Number | Date | Country | Kind |
---|---|---|---|
2011-181271 | Aug 2011 | JP | national |
This application is a continuation application of PCT application No. PCT/JP2012/071052, filed on Aug. 21, 2012, which is based on and claims the benefit of priority from prior Japanese Patent Application No. 2011-181271, filed on Aug. 23, 2011, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2012/071052 | Aug 2012 | US |
Child | 14186345 | US |