JP5066208B2 - Printed circuit board manufacturing method, printed circuit board, and electronic device including the printed circuit board - Google Patents

Description

  The present invention relates to a method for manufacturing a printed circuit board configured by mounting a semiconductor package on a printed wiring board, a printed circuit board, and an electronic apparatus including the printed circuit board.

  Conventionally, electronic devices such as personal computers and hard disk devices have printed circuit boards. The printed circuit board is configured by mounting a semiconductor package on a printed wiring board. A conventional printed circuit board is manufactured by, for example, a manufacturing method described in Patent Document 1. In this manufacturing method, a BGA (Ball Grid Array) mounting process on a printed wiring board having a through hole and an underfill material pouring process into a gap between the printed wiring board and the BGA are performed. Before these, a process of closing the through hole with a closing material such as an adhesive is performed.

JP 2004-79621 A

  Conventionally, in a printed circuit board, an underfill material is poured between the semiconductor package and the printed wiring board as in the above-described printed circuit board in order to increase the reliability of the joint portion between the semiconductor package and the printed wiring board. Sometimes.

  However, when a through hole is formed in the printed wiring board, there is a problem that when the underfill material is poured, the underfill material flows out to the back side through the through hole.

  In this respect, it is possible to prevent the underfill material from flowing out to the back surface side by performing a process of closing the through hole with the closing material as in the manufacturing method described in Patent Document 1 described above.

  However, the manufacturing method described in Patent Document 1 has a problem that the manufacturing process becomes complicated because a closing material must be adhered to the back surface (opposite side) of the mounting surface on which the semiconductor package is mounted. Moreover, even if the opposite side of the through hole is blocked, the mounting surface side is open and the through hole remains hollow, so it is not possible to eliminate the entry of the underfill material into the through hole. It is also impossible to prevent wetting and spreading on the mounting surface side. Therefore, the underfill material spreads more than necessary on the printed wiring board, and an extra underfill material must be applied.

  Patent Document 1 also discloses that the mounting surface side of the semiconductor package is closed with a closing material. However, in this method, it is necessary to use a material different from that for mounting the semiconductor package in order to close the through hole, which makes the manufacturing process complicated and may reduce the reliability at the joint portion. .

  In addition, there is an idea of avoiding the flow of the underfill material by moving the location of the through hole to another location, but this movement is necessary to ensure the electrical characteristics of the printed wiring board, such as the convenience of wiring. Can be difficult.

  Accordingly, the present invention has been made to solve the above-described problems, and a printed circuit board manufacturing method, a printed circuit board, and a printed circuit board thereof that can easily manufacture a printed circuit board that prevents the underfill material from flowing out to the back surface side. An object is to provide an electronic device including a circuit board.

  In order to solve the above problem, the present invention provides a mounting region having a plurality of electrode pads electrically connected to a plurality of solder bumps provided in a semiconductor package, and a first through hole located in the mounting region. A preparatory step of preparing a printed wiring board provided with a second through hole located at a position outside the mounting region, and the first through hole of the printed wiring board prepared by the preparatory step A coating step of applying a solder paste so as to cover the opening of the hole and the opening of the second through hole; and the opening of the first through hole and the opening of the second through hole by the coating step Mounting the plurality of solder bumps of the semiconductor package on the plurality of electrode pads of the printed wiring board to which the solder paste is applied. A mounting step; a side on which the printed wiring board on which the semiconductor package is mounted by the mounting step is heated to join the solder bump and the electrode pad, and the solder paste is dissolved and the solder paste is applied The second through-hole is disposed so that a part of the solder paste protrudes outside the printed wiring board to stop the filler flowing out between the semiconductor package and the printed wiring board. It has a joining process which fills up the inside of the hole with the solder paste, and a pouring process of pouring the filler between the semiconductor package and the printed wiring board.

  The present invention also includes a semiconductor package provided with a plurality of bumps, a mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, and a through hole located at a position outside the mounting region. , A printed wiring board provided with a filler, a filler filled between the semiconductor package and the printed wiring board, and the filler protruding from the surface of the printed wiring board on the side where the semiconductor package is disposed. A printed circuit board having a protrusion capable of suppressing the outflow of the solder and solder for closing the through hole is provided.

  Furthermore, the present invention provides a semiconductor package provided with a plurality of bumps, a mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, and a through hole located at a position outside the mounting region. , A printed wiring board provided with a filler, a filler filled between the semiconductor package and the printed wiring board, and the filler protruding from the surface of the printed wiring board on the side where the semiconductor package is disposed. There is provided an electronic device including a protrusion having a protrusion capable of suppressing the outflow of the solder and closing the through hole.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the printed circuit board which can manufacture easily the printed circuit board which prevented the flow to the back surface side of an underfill material, a printed circuit board, and an electronic device provided with the printed circuit board are obtained.

It is a perspective view which shows the structure of the external appearance of a personal computer. It is the top view which abbreviate | omitted some printed wiring boards. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 of a printed circuit board obtained by mounting a BGA described later on a printed wiring board and pouring an underfill material. Similarly, it is a sectional view taken along line IV-IV. It is sectional drawing similar to FIG. 3 of BGA. It is sectional drawing similar to FIG. 3 of a printed wiring board. It is a figure which shows a through hole and a solder paste, (a) is before solder paste formation, (b) is after solder paste formation, (c) is sectional drawing which shows after solder reflow. It is a figure which shows the through hole and solder paste concerning a modification, (a) is sectional drawing which shows after solder paste formation, (b) is after solder reflow, (c) is another sectional drawing. It is sectional drawing similar to FIG. 3 of BGA in the printed circuit board relevant to this invention. Similarly, it is sectional drawing similar to FIG. 3 of a printed wiring board. Similarly, it is sectional drawing similar to FIG. 4 of a printed circuit board.

  Embodiments of the present invention will be described below. In addition, the same code | symbol is used for the same element and the overlapping description is abbreviate | omitted.

  FIG. 1 is a perspective view showing an external configuration of the personal computer 1. The personal computer 1 is an electronic device according to an embodiment of the present invention, and has a printed circuit board 10 to be described later. In this embodiment, a personal computer 1 as shown in FIG. 1 will be described as an example of an electronic device provided with a printed circuit board.

  A personal computer 1 shown in FIG. 1 is a portable notebook computer having a main body housing 2 and a display unit 3 in which a liquid crystal display panel is incorporated.

  The main body housing 2 is provided with a keyboard 4 on the front side and a printed circuit board 10 inside.

  Here, FIG. 2 is a plan view in which a printed wiring board 11 to be described later is partially omitted, and FIG. 3 is a printed circuit board obtained by mounting a BGA 20 to be described later on the printed wiring board 11 and pouring an underfill material 30 thereon. 10 is a cross-sectional view taken along line III-III, and FIG. 4 is a cross-sectional view taken similarly along line IV-IV.

  As shown in FIG. 3, the printed circuit board 10 includes a printed wiring board 11, a BGA 20 as a semiconductor package, and an underfill material 30 as a filler, and the BGA 20 is mounted on the printed wiring board 11. An underfill material 30 is poured between the BGA 20 and the printed wiring board 11.

  As shown in FIG. 2, the printed wiring board 11 has a mounting area 12 on which the BGA 20 is mounted on a surface (mounting surface) 11a on the side where the BGA 20 is mounted. Further, the printed wiring board 11 has a plurality of copper pads 13 as electrode pads for mounting solder bumps 25 to be described later and a through hole 14 formed in the mounting area 12 on the mounting surface 11a. Another through hole 15 is formed in the vicinity of the outer side of 12. The copper pad 13 is formed corresponding to a solder bump 25 described later of the BGA 20.

  The through holes 14 and 15 penetrate the mounting surface 11a of the printed wiring board 11 and the back surface (back surface) 11b. The through holes 14, 15 are closed by solder 17 and filled with solder 17.

  The BGA 20 includes an IC chip 21, a sealing resin 22, a core material 23, a solder resist 24, solder bumps 25, and a die attach film 26. The BGA 20 is a resin package in which an IC chip 21 is mounted on the front side of a core material 23 via a die attach film 26, and the entire front side is sealed with a sealing resin 22, and a plurality of solder bumps 25 are provided on the back side. Yes.

  Further, the underfill material 30 is prevented from flowing out in the outward direction by a solder protrusion (projection) 17 a, which will be described later, of the solder 17 disposed in the through hole 15, and is disposed inside the through hole 15.

  The printed circuit board 10 having the above configuration is manufactured as follows. Here, FIG. 5 is a cross-sectional view of the BGA 20 similar to FIG. 3, and FIG. 6 is a cross-sectional view of the printed wiring board 11 similar to FIG.

  First, the BGA 20 having the above-described configuration and the printed wiring board 11 are prepared. However, the through holes 14 and 15 of the printed wiring board 11 are in a hollow state without being filled with the solder 17.

  Next, a solder printing process for the printed wiring board 11 is performed, and the same solder is applied to the surfaces of the copper pads 13 and the through holes 14 and 15 formed on the mounting surface 11a at a time, as shown in FIG. Thus, the solder paste 18 is formed on the surfaces of the copper pad 13 and the through holes 14 and 15. In this case, an amount of solder corresponding to the size of the surface of the copper pad 13 is applied, and the openings of the through holes 14 and 15 can be closed and the interior of the through holes 14 and 15 can be filled. Apply the amount of solder. In this case, a flux 19 is applied to the surface of the solder paste 18. Also, solder is applied to the through holes 14 and 15 so as to close the respective openings.

  Next, the positions of the solder bumps 25 and the copper pads 13 are made to face each other, and the solder bumps 25 are placed on the copper pads 13 via the solder paste 18 and mounted.

  Subsequently, the printed wiring board 11 together with the BGA 20 is placed in a reflow furnace (not shown) and heated to perform solder reflow. As a result, the solder paste 18 is melted and the solder bumps 25 and the copper pads 13 are joined by solder. At this time, the bonding between the solder bump 25 and the copper pad 13 may be cured by heating the printed wiring board 11 together with the BGA 20. Instead of heating the printed wiring board 11, the printed wiring board 11 may be irradiated with ultraviolet rays together with the BGA 20 to cure the bonding between the solder bump 25 and the copper pad 13.

  Further, when this solder reflow is performed, as shown in FIGS. 7B and 7C, the solder paste 18 applied to the through holes 14 and 15 is also melted, and the solder paste 18 is put inside the through holes 14 and 15. Get in. However, since the through holes 14 and 15 are coated with an amount of solder that can close the openings of the through holes 14 and 15 and fill the inside thereof, a part of the applied solder is formed in the through holes 14 and 15. It is located on the outside, and the opening is closed from the outside. As a result, as shown in FIG. 7C, solder protrusions 17 a formed by melting the solder paste 18 are formed on the through holes 15. Further, the flux 19 remains on the surface of the solder protrusion 17a.

  Subsequently, an underfill material 30 is poured between the BGA 20 and the printed wiring board 11. Thus, the above-described printed circuit board 10 can be manufactured.

  Here, with reference to FIGS. 9-11, the printed wiring board 101 relevant to this invention is demonstrated. As shown in FIG. 9, the printed wiring board 101 is obtained by mounting a BGA 20 similar to the printed circuit board 10 described above on a printed wiring board 91 and pouring an underfill material 30 between the BGA 20 and the printed wiring board 91. is there.

  However, as shown in FIG. 10, since the printed wiring board 91 is subjected to solder printing only for the copper pad 13 excluding the through holes 14 and 15 when the solder printing process is performed, Although a solder paste 18 is formed on 13, the solder paste 18 is not formed on the through holes 14 and 15. Therefore, the through holes 14 and 15 remain penetrating without entering the solder.

  Therefore, as shown in FIG. 11, when the BGA 20 is mounted and then the underfill material 30 is poured, the underfill material 30 is formed from the mounting surface 91a side through the through holes 14, as shown by the circle P1. 15 flows out to the back surface 91b side. In addition, the underfill material 30 spreads outside the through hole 15 on the mounting surface 91a like the part marked with the circle P2, and the wetting spread outside the through hole 15 occurs. There are challenges.

  On the other hand, in the printed circuit board 10, solder paste 18 is formed on the copper pad 13 and the through holes 14 and 15 by performing solder printing on the copper pad 13 and the through holes 14 and 15 at the manufacturing stage. Yes. Therefore, the through holes 14 and 15 are filled with the solder 17 (and the flux 19).

  Therefore, in the printed circuit board 10, even when the underfill material 30 is poured, the underfill material 30 does not flow out through the through holes 14 and 15 to the back surface 11 b side. Therefore, since the printed circuit board 10 can be manufactured without pouring the unnecessary underfill material 30, the amount of the required underfill material 30 can be suppressed. In addition, in the case of the printed circuit board 10, since the solder protrusions 17 a are formed, the movement of the underfill material 30 is prevented by the solder protrusions 17 a, and the underfill material 30 is wet outside the through holes 15. Expansion is difficult to occur, and the underfill material 30 is arranged inside the through hole 15. Therefore, the amount of the underfill material 30 required can be further suppressed.

  Further, since it is not necessary to move the positions of the through holes 14 and 15 in order to avoid the underfill material 30 from flowing out, the through holes 14 and 15 are optimally positioned in consideration of electrical characteristics such as the convenience of wiring. Therefore, the printed circuit board 10 has a high degree of design freedom.

  In addition, the printed circuit board 10 uses the same solder for the surfaces of the through holes 14 and 15 together with the copper pad 13 during the solder printing process on the copper pad 13 on the mounting surface 11a side of the printed wiring board 11. The solder paste 18 is formed at the same timing.

  As described above, in the method of manufacturing the printed circuit board 10, the through holes 14 and 15 are closed only by slightly changing the solder printing location. Therefore, it is described in Japanese Patent Application Laid-Open No. 2004-79621. Unlike the case where the back side is closed with a plugging material as in this manufacturing method, the manufacturing process is not complicated, and the printed circuit board 10 can be easily manufactured.

  Further, since the through holes 14 and 15 are closed using the same solder as the copper pad 13 on the mounting surface 11a side, the reliability at the joint portion is not lowered.

(Modification)
In the above embodiment, the solder paste 18 is formed on the mounting surface 11a side of the through holes 14 and 15, but as shown in FIGS. 15 may be formed on the back surface 11b side. In this case, when performing solder printing, the through holes 14 and 15 are coated with an amount of solder that can close the opening and fill the interior. Then, when solder reflow is performed and the printed wiring board 11 is heated, the solder paste 18 melts and enters the through holes 14 and 15, and as shown in FIG. , 15 is filled with solder 17, the through holes 14, 15 are closed, and the respective openings are closed. Depending on the amount of solder to be applied, as shown in FIG. 8C, there may be a slight solder wetting spread 18a on the mounting surface 11a side. In this case as well, the inside of the through holes 14 and 15 is the solder 17. The through holes 14 and 15 are closed by being filled.

  Therefore, even if the underfill material 30 is poured after the BGA 20 is mounted on the mounting surface 11a side, the underfill material 30 does not flow through the through holes 14 and 15 to the back surface 11b side. Therefore, even if it manufactures in this way, the unnecessary pouring of the underfill material 30 becomes unnecessary. In this manufacturing method, it is necessary to perform solder printing on the back surface 11b side, but since the same solder as the solder applied to the copper pad 13 can be used, the manufacturing process is not complicated. In this case, the amount of solder applied to the back surface 11b side of the through holes 14 and 15 may be increased so that the solder protrudes to the mounting surface 11a side. If it carries out like this, the wetting spread in the mounting surface 11a side of the underfill material 30 can be prevented by the protruding solder.

  Furthermore, in the above embodiment, the BGA 20 is mounted on either the mounting surface 11a or the back surface 11b, but the BGA 20 may be mounted on both the mounting surface 11a and the back surface 11b. In this case, for example, the mounting surface 11a is subjected to a process of applying solder to both the copper pad 13 and the through holes 14 and 15 (extended application process), and the back surface 11b is applied only to the copper pad 13. What is necessary is just to perform the process (application | coating process for mounting). Even in this case, since the through holes 14 and 15 can be closed with solder, it is possible to prevent the underfill material 30 from flowing out to the back surface.

  The above description is the description of the embodiment of the present invention, and does not limit the apparatus and method of the present invention, and various modifications can be easily implemented. In addition, an apparatus or a method configured by appropriately combining components, functions, features, or method steps in each embodiment is also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Personal computer, 10 ... Printed circuit board, 11 ... Printed wiring, 12 ... Mounting area, 13 ... Copper pad, 14, 15 ... Through-hole, 17 ... Solder, 18 ... Solder paste, 20 ... BGA, 21 ... IC chip 25 ... solder bumps, 30 ... underfill material.

Claims (15)

A mounting area having a plurality of electrode pads electrically connected to a plurality of solder bumps provided in the semiconductor package, a first through hole located in the mounting area, and a position away from the mounting area A preparation step of preparing a printed wiring board provided with a second through hole;
An application step of applying a solder paste so as to cover the opening of the first through hole and the opening of the second through hole of the printed wiring board prepared in the preparation step; The plurality of solder bumps of the semiconductor package are opposed to the plurality of electrode pads of the printed wiring board in which the solder paste is applied to the opening of one through hole and the opening of the second through hole. Mounting process to mount,
Heating the printed wiring board on which the semiconductor package is mounted by the mounting step to join the solder bump and the electrode pad, and dissolving the solder paste to apply the solder paste A portion of the solder paste protrudes from the outside of the board, and a protrusion is disposed to stop the flow of the filler material flowing between the semiconductor package and the printed wiring board. A joining step filled with the solder paste;
A method for manufacturing a printed circuit board, comprising: a pouring step of pouring the filler between the semiconductor package and the printed wiring board.   The solder paste is applied to the opening portion of the first through hole and the opening portion of the second through hole in the applying step. The opening portion of the first through hole and the opening of the second through hole are applied. 2. The method of manufacturing a printed circuit board according to claim 1, wherein the method is performed so as to block the portion.   When heating the printed wiring board, the solder paste to the opening of the first through-hole and the opening of the second through-hole applied in the application step becomes the first through-hole and 2. The opening of the first through hole and the opening of the second through hole on the side opposite to the side to which the solder paste is applied flown into the second through hole. A method for producing a printed circuit board according to claim 1.   The solder paste is applied so as to cover the opening of the first through hole and the opening of the second through hole located in the vicinity of the mounting region in the applying step. The manufacturing method of printed circuit board as described.   2. The printed circuit board according to claim 1, further comprising a curing step of curing the bonding between the solder bump and the electrode pad with respect to the printed wiring board before the filling material is poured in the pouring step. Production method.   6. The method for manufacturing a printed circuit board according to claim 5, wherein the curing step is performed by irradiating the printed wiring board with ultraviolet rays.   6. The method for manufacturing a printed circuit board according to claim 5, wherein the curing step is performed by heating the printed wiring board. A semiconductor package provided with a plurality of bumps;
A printed wiring board provided with a mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, and a through hole located out of the mounting region;
A filler filled between the semiconductor package and the printed wiring board;
A solder that protrudes from the surface of the printed wiring board on the side where the semiconductor package is disposed and can suppress outflow of the filler, and closes the through hole;
Printed circuit board with The filler has an inclined surface that extends along the surface of the printed wiring board as it goes from the semiconductor package side to the printed wiring board side;
The printed circuit board according to claim 8, wherein the protruding portion is provided corresponding to a peripheral edge portion of the inclined surface that contacts the printed wiring board. A semiconductor package provided with a plurality of bumps;
A printed wiring board provided with a mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, and a through hole located out of the mounting region;
A filler filled between the semiconductor package and the printed wiring board;
Solder having a protruding portion protruding from the surface of the printed wiring board on which the semiconductor package is disposed, and closing the through hole;
With
The printed circuit board according to claim 1, wherein the protruding portion is provided corresponding to a peripheral edge portion of the filler that contacts the printed wiring board.   The solder is filled in the through hole from the opening on the side where the protrusion of the through hole is provided to the opening on the side opposite to the side where the protrusion is provided. The printed circuit board as described in any one of Claims 8-10. The printed circuit board according to claim 11 , wherein the protrusion protrudes outward from a peripheral edge of the opening. A semiconductor package provided with a plurality of bumps;
A mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, a first through hole located in the mounting region, and a second through hole located in a position away from the mounting region; A printed wiring board provided with
A filler filled between the semiconductor package and the printed wiring board;
The bump and the electrode pad are joined and embedded in the first through hole and the second through hole, and the opening of the first through hole and the opening of the second through hole are formed. Each covered and closed solder,
A protrusion provided integrally with the solder embedded in the second through-hole, and protruding to the outside of the printed wiring board to suppress the outflow of the filler;
A printed circuit board comprising: A semiconductor package provided with a plurality of bumps;
A printed wiring board provided with a mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, and a through hole located out of the mounting region;
A filler filled between the semiconductor package and the printed wiring board;
A solder that protrudes from the surface of the printed wiring board on the side where the semiconductor package is disposed and can suppress outflow of the filler, and closes the through hole;
With electronic equipment. A semiconductor package provided with a plurality of bumps;
A mounting region having a plurality of electrode pads electrically connected to the plurality of bumps, a first through hole located in the mounting region, and a second through hole located in a position away from the mounting region; A printed wiring board provided with
A filler filled between the semiconductor package and the printed wiring board;
The bump and the electrode pad are joined and embedded in the first through hole and the second through hole, and the opening of the first through hole and the opening of the second through hole are formed. Each covered and closed solder,
A protrusion provided integrally with the solder embedded in the second through-hole, protruding outside the printed wiring board and capable of suppressing the outflow of the filler;
An electronic device comprising:

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