JP2008251623A - Manufacturing method of wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a wiring board capable of improving yields by reducing flaws on a substrate and suppressing warpage in the substrate. <P>SOLUTION: The manufacturing method of a wiring board comprises a coating process for coating, with solder paste, a pad arranged on the small substrate of a substrate body, having a product section with a plurality of small substrates and a connection section for connecting the plurality of small substrates and a peripheral section positioned at the periphery of the product section; a mounting process for mounting the substrate body on a stand plate DT1, having a frame body section DTS and a support projection DTB arranged in the opening of the frame body section DTS, so that the upper surface of the frame body section DTS and the lower surface of the peripheral section come into contact and the support projection DTB point-supports the connection section from a lower part; and a fixing process for fixing the substrate body to the stand plate, by inserting the peripheral section of the substrate body and the frame body section of the stand plate into a recessed groove in a holding tool, while the substrate body is placed on the stand plate with the holding tool having the recessed groove. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wiring board.

When the substrate on which the solder paste is applied is heated in a reflow furnace or the like, the substrate may be warped. In general, when a substrate warps, a connection failure is likely to occur when an electronic component such as an IC chip is mounted or when connected to another substrate such as a mother board. There is a need for a method of manufacturing a wiring board.
As a method for manufacturing a wiring board capable of suppressing board warpage, a frame-shaped peripheral edge portion DTS and a plurality of columnar members shown in FIG. 13 are arranged in a lattice shape so as to connect the inner side surfaces of the peripheral edge portion. FIG. 14 shows a cross-sectional shape of the columnar member, which is integrally formed with a frame portion DTW having a stepped shape (not shown) whose main surface side and back surface side are thinner than the inside. A substrate body 901 including a connected product portion 915 to which a plurality of small substrates 917 are connected is placed, and using a holding jig HJ having a recessed groove HJM shown in FIG. A technique for heating the substrate body 901 while inserting the peripheral edge portion DTS of the plate DT into the recessed groove HJM of the holding jig HJ and holding the substrate body 901 on the base plate DT is disclosed (for example, Patent Document 1). reference).
JP 2003-234366 A

However, it has been found that with the above method, the back surface of the substrate main body 901 may be damaged and the yield may be reduced.
According to the above method, the upper part of the frame part DTW formed in the grid pattern of the base plate DT is brought into contact with the connecting part 919 (not the product part) that connects the plurality of small substrates 917 (the product part). The substrate body 901 can be placed on the base plate DT. However, when the substrate body 901 is held (fixed) on the base plate DT at a position deviated from the intended placement position, the upper portion of the frame portion DTW formed in the lattice shape of the base plate DT is on the lower surface of the small substrate 917. There is a possibility that the insulating protective layer such as a solder resist on the lower surface of the small substrate 917, the pad or the like may be damaged. In particular, from the standpoint of improving yield, it is desirable that the connecting portion that is not a product portion has a narrow width. Therefore, a substrate body having a narrow connecting portion may be used. In such a case, the frame portion of the base plate DT is used. When the upper part of the DTW and the lower surface of the small substrate are in contact with each other, there is a higher possibility that the lower surface of the small substrate will be damaged.
If the lower surface of the small substrate 917 is scratched, as a result, the lower surface of the wiring board which is a product also remains, and the finished appearance of the wiring substrate deteriorates. Therefore, the wiring substrate may be defective and the yield may be reduced. is there.

  In view of the above, an object of the present invention is to provide a method of manufacturing a wiring board capable of improving the yield by reducing the damage to the board and suppressing the warpage of the board.

  A method for manufacturing a wiring board according to an aspect of the present invention includes a product part including a plurality of small boards and a connecting part that connects the plurality of small boards, and a peripheral part located at the periphery of the product part. An application step of applying a solder paste onto a pad disposed on the small substrate of the main body, a frame body portion, a support protrusion disposed in an opening of the frame body portion, the support protrusion and the frame body portion; The substrate body is mounted so that the upper surface of the frame body portion and the lower surface of the peripheral edge portion are in contact with a base plate having a connection portion for connecting the connection portion, and the support protrusions point-support the connection portion from below. And a holding jig having a concave groove to hold the peripheral portion of the substrate main body and the frame body portion of the base plate in a state where the substrate main body is placed on the base plate. By inserting into the concave groove of the tool and sandwiching the upper surface of the peripheral edge and the lower surface of the frame body , Characterized by comprising a fixing step of fixing the substrate main body to the base plate, a heating step of heating the substrate body fixed to the base plate, the.

  According to another aspect of the present invention, there is provided a method for manufacturing a wiring board, comprising: applying a solder paste on a pad disposed on a product portion of a substrate body having a product portion and a peripheral portion located at a peripheral edge of the product portion. A placing step of placing the substrate body such that an upper surface of the frame body portion and a lower surface of the peripheral edge portion are in contact with a base plate comprising the frame body portion, and a holding jig having a groove Using the substrate body placed on the base plate, the peripheral edge portion of the substrate main body and the frame body portion are inserted into the concave groove of the holding jig, and the upper surface of the peripheral edge portion and the frame body are used. A fixing step of fixing the substrate main body to the base plate by sandwiching the lower surface of the part, and a heating step of heating the substrate main body fixed to the base plate.

According to the method for manufacturing a wiring board according to one aspect of the present invention, since the peripheral portion of the substrate body and the frame body portion of the base plate are fixed using a holding jig during heating, the warpage of the substrate body is prevented. Can be suppressed. In addition, since the substrate main body is fixed to the base plate with the support protrusions of the base plate supporting the connecting portion of the substrate main body from below, it is possible to further suppress the warpage of the substrate main body.
Furthermore, even if the board body is fixed to the base plate at a position shifted from the intended mounting position, and the lower surface of the small board and the support protrusions of the base board are in contact, the support protrusions of the base board point to the board body. Therefore, the contact area between the base plate and the lower surface of the small substrate is small, and the occurrence of scratches over a wide range can be suppressed. This can improve the yield of the wiring board.

  In addition, according to the method for manufacturing a wiring board according to another aspect of the present invention, the peripheral part of the board body and the frame body part of the base plate are fixed using a holding jig during heating. Can be suppressed. In addition, even when the substrate body is fixed to the base plate at a position deviated from the intended placement position, the base plate is composed only of the frame body portion, and the part that contacts the lower surface of the product portion is the base plate. Since it is not formed, contact between the base plate and the lower surface of the product portion can be reliably prevented. As a result, it is possible to prevent the occurrence of scratches on the lower surface of the product portion of the board body, and to improve the yield of the wiring board.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 and FIG. 2 are plan views respectively showing the configuration of the first main surface of the wiring board 1 and the second main surface opposite to the first main surface. FIG. 3 is a cross-sectional view schematically showing a cross-sectional configuration of the wiring board 1. FIG. 4 is a schematic enlarged cross-sectional view showing a cross-sectional configuration around the pad 13 formed on the second main surface of the wiring board 1.

The wiring board 1 to which the present invention is applied has a substantially plate shape having an outer shape of approximately 35 mm × about 35 mm × about 1 mm in a substantially rectangular shape in plan view. Pads 11 made of copper are arranged on the first main surface of the wiring board 1, and pads 13 made of copper are arranged on the second main surface of the wiring board 1. The wiring board 1 includes a base 20 made of glass fiber reinforced epoxy resin, wiring layers made of copper platings 21, 22, 26, and 33, and resin insulating layers 29 and 35.
As a constituent material of the base 20, for example, a polyimide resin, a bismaleimide-triazine resin, a polyphenylene ether resin, or the like may be used in addition to the glass fiber reinforced epoxy resin described above.
In addition to the resin substrate described above, for example, a ceramic substrate or a metal substrate may be used as the substrate 20.

  The wiring board 1 has a plurality of pads 11 (hereinafter referred to as an array corresponding to an input / output terminal arrangement pattern of an IC chip as an uppermost wiring layer at a central portion (approximately 10 mm square in the center) of the first main surface. , Also expressed as “FC pad 11”). A plurality of pads 13 (hereinafter also referred to as “BGA pads 13”) are arranged on the second main surface of the wiring board 1 so as to be distributed over substantially the entire surface (approximately 30 mm square). The BGA pad 13 is a connection terminal connected to a terminal on the motherboard side, and can be connected to a motherboard (not shown).

  Also, a solder resist layer 15 is formed on the surface of the wiring substrate 1 with a part of the copper platings 21 and 22 constituting the FC pad 11 and the BGA pad 13 exposed. That is, the pads (FC pad 11 and BGA pad 13) on both sides are surrounded by the uppermost solder resist layer 15 of the wiring board 1 (periphery), and the recess 16 in which the solder resist layer 15 is not formed. , 17.

  Specifically, in the wiring board 1 of the present embodiment, the recess 16 is formed so that the diameter of the FC pad 11 is approximately 100 μm (however, the size depends on the IC chip to be mounted). Slightly different). And the recessed part 17 is formed so that the diameter of the BGA pad 13 may be set to about 500 micrometers. In addition, the solder resist layer 15 is formed approximately 20 μm higher than the surface of the BGA pad 13.

  Further, solder bumps 18 made of Pb—Sn eutectic solder for bonding an IC chip by a flip chip mounting method protrude from the solder resist layer 15 on the FC pad 11 arranged on the first main surface of the wiring board 1. It is formed like this. The solder bumps 18 are formed so as to directly contact the FC pad 11 and cover the surface of the FC pad 11 by a manufacturing method described later.

  Further, the BGA pad 13 arranged on the second main surface has a solder layer 19 made of Pb—Sn eutectic solder for bonding and attaching a solder ball (in this embodiment, φ = 600 μm is preferable). The BGA pad 13 is formed so as to cover the surface. The solder layer 19 is formed so as to be in contact with the BGA pad 13 such that the upper surface (more specifically, the apex) is positioned lower than the upper surface of the solder resist layer 15 by a manufacturing method described later. (See FIG. 4). More specifically, the solder layer 19 is formed so that its apex is at a position about 10 μm lower than the upper surface of the solder resist layer 15.

Next, a method for manufacturing the wiring board 1 having the above configuration will be described.
5A to 5G are explanatory views showing the manufacturing process of the wiring board 1. In this embodiment, the manufacturing process (FIG. 5A), the cleaning process (FIG. 5B), the printing process (FIGS. 5C and 5D), the placing process (FIG. 5E), the fixing process (FIG. 5F), and the reflow process. Since the wiring board 1 is manufactured through the steps (FIG. 5G) and the cutting step (not shown), each step will be described below in this order. However, since the substrate body 101 is manufactured by a well-known method, it will be briefly described here.

  FIG. 6 is a perspective view showing the substrate body 101 in a simplified manner. The substrate main body 101 includes a product part 115 including a plurality of small boards 117 and a connecting part 114 that connects the plurality of small boards 117, and a peripheral part 121 positioned at the periphery of the product part 115. The small board 117 is a portion that becomes the wiring board 1 through a cutting process after the reflow process (FIG. 5G).

  The substrate main body 101 has a substantially plate shape having an outer shape of approximately 400 mm × approximately 400 mm × approximately 1 mm and having a substantially rectangular shape in plan view. The substrate body 101 has a product part 115 at the center thereof, and a peripheral part 121 at the periphery of the product part 115. Of these, the product portion 115 is a connected product portion in which 10 × 10 = 100 (in the figure, 16 simplified) small substrates 117 are connected via the connecting portion 114. Each small substrate 117 has a substantially plate shape having an outer shape of approximately 35 mm × about 35 mm × about 1 mm in a substantially rectangular shape in plan view.

  In the manufacturing process of the substrate body 101, first, copper foil 25 (about 10 to 15 μm) is formed on both surfaces of the base body 20. Thereafter, through holes (through holes) are formed in the base 20 with a drill or the like, and copper plating 26 is applied to both sides of the base 20 on which the copper foil 25 is formed and the side surfaces in the through holes. The plating 26 is connected through a through hole. Further, the surface of the copper plating 26 on the substrate 20 is roughened, and the through holes are filled with a filler 27 (for example, epoxy resin).

  Then, an etching resist layer (not shown) is formed on the copper platings 26 on both sides, and a part of the etching resist layer is removed by performing exposure and development using a glass mask corresponding to the wiring pattern. Then, etching is performed from above the etching resist layer using an etching solution, thereby removing a part of the copper plating 26 and the copper foil 25 below the copper plating 26 to form a wiring layer (wiring pattern) by the copper plating 26. To do.

  Thereafter, the remaining etching resist layer is removed from the substrate 20, the surface of the copper plating 26 is roughened, and a resin insulating layer 29 made of an insulating film is formed thereon. After the resin insulating layer 29 is formed, a part of the resin insulating layer 29 is removed by exposure and development to form a via 31 (hole), and the resin insulating layer 29 is thermoset and roughened. Then, a plating resist having a predetermined pattern is formed on the surface of the resin insulating layer 29, and selectively plated with copper 33 so as to be connected to the first-layer copper plating 26 (wiring layer). A layer (wiring pattern) is formed. Furthermore, a resin insulating layer 35 is formed on the substrate 20 on which the second wiring layer is formed. In addition, a wiring layer is formed in multiple layers by repeating the formation of a wiring layer (wiring pattern) by copper plating and the formation of a resin insulating layer by such a method (known photolithography technique, additive method, subtractive method, etc.). .

  Then, after forming the uppermost wiring layer, the surfaces of the copper platings 21 and 22 constituting the wiring layer are roughened, and a solder resist layer 15 made of a photosensitive epoxy resin is formed thereon. After the solder resist layer 15 is formed, only the solder resist layer 15 on the surfaces of the pads 11 and 13 to be arranged is selectively removed by exposure and development to form the recesses 16 and 17, thereby forming the copper platings 21 and 22. Are exposed, and pads 11 and 13 surrounded by the solder resist layer 15 are formed.

  After the pads 11 and 13 are formed, the solder resist layer 15 is subjected to treatment such as thermosetting and surface roughening. With the above processing, the substrate body 101 that electrically connects the FC pad 11 and the BGA pad 13 via the lower wiring layer is completed. In addition, after the substrate body 101 is completed in this way, the processing is shifted to a cleaning process.

  In the cleaning process, the surfaces of the pads 11 and 13 are soft-etched by immersing the surfaces of the pads (FC pad 11 and BGA pad 13) in a sodium persulfate solution, and impurities such as oxide films on the surfaces of the pads 11 and 13 are removed. To do. In addition, the surfaces of the pads 11 and 13 are cleaned by immersing the surfaces of the pads (FC pad 11 and BGA pad 13) in sulfuric acid, and oxide films and other impurities on the surfaces of the pads 11 and 13 are removed from the surfaces of the pads 11 and 13. To do.

  This process is mainly a process for improving the wettability of the solder by removing the oxide film by cleaning the surfaces of the pads 11 and 13. In this embodiment, two types of solutions (sodium persulfate solution and sulfuric acid) are used to remove the oxide film, and impurities are removed from the surfaces of the pads 11 and 13, but only one of these solutions is used. However, the oxide film and impurities can be sufficiently removed, and in the cleaning process, only cleaning with a sodium persulfate solution or cleaning with sulfuric acid may be performed.

  After this cleaning process, the solder paste 41 is directly screen-printed (ie, solder-printed) on the pads (FC pad 11 and BGA pad 13) (printing process). In this printing process, first, solder printing is performed on the FC pad 11 (first solder printing process). In the solder printing on the FC pad 11, a metal mask having a through hole having an array pattern corresponding to the FC pad 11 is used. The opening diameter of the through hole and the thickness of the metal mask are set according to the shape of the solder bump 18 to be formed.

  In the first solder printing process, the metal mask is placed on the upper surface of the substrate body 10 (that is, the first principal surface 101a) after being placed on the mounting table 43 with the second principal surface 101b of the substrate body 101 facing down. By applying the solder paste 41 from the upper surface of the metal mask, the solder paste 41 is directly printed on the surface of the FC pad 11 formed on the first main surface 101a of the substrate body 10 through the through hole. In the present embodiment, by using the metal mask, the printing amount of the solder paste 41 is adjusted so that the solder bumps 18 when the wiring board 1 is completed protrude from the solder resist layer 15.

  When this step is completed, the metal mask is peeled off as shown in FIG. 5C. FIG. 5C shows an aspect of the substrate body 101 in a state where the metal mask is peeled off after the solder printing on the surface of the FC pad 11. Then, after turning the substrate body 101 upside down and placing it on the mounting table 43 with the first main surface 101a facing down, a metal mask 47 having a through-hole 45 with a pattern corresponding to the BGA pad 13 is placed on the second side of the substrate body 101. After placing on the main surface 101 b and then applying the solder paste 41 from the upper surface of the metal mask 47, the surface of the BGA pad 13 formed on the second main surface 101 b of the substrate body 101 through the through hole 45 is applied. The solder paste 41 is directly printed (second solder printing process).

FIG. 5D shows an aspect of the substrate body 101 when the solder paste 41 is printed on the surface of the BGA pad 13.
FIG. 7 is an explanatory diagram showing an enlarged configuration of the surface of the BGA pad 13 when the solder paste 41 is printed.

  As in the case of solder printing on the FC pad 11, in the second solder printing process, the metal mask 47 is formed by setting the opening diameter and thickness of the through hole 45 for the BGA pad 13. By using the solder paste, the printing amount of the solder paste is adjusted so that the upper surface of the solder layer 19 when the wiring board 1 is completed is lower than the upper surface of the solder resist layer 15.

  Further, the mounting table 43 supports the end portion of the substrate body 101 on which the FC pad 11 is not formed so as not to contact the central portion of the first main surface 101a of the substrate body 101 where the FC pad 11 is formed. In this embodiment, by using this mounting table 43, solder printing is performed in the order of the FC pad 11 and the BGA pad 13, so that the solder paste 41 printed on the FC pad 11 side is not destroyed. Both sides are solder printed.

In the second solder printing process, when the metal mask 47 is placed on the second main surface 101b of the substrate body 101 where the BGA pad 13 is exposed, the through hole 45 is shifted from the BGA pad 13 by a predetermined distance. Then, it may be arranged on the second main surface 101b of the substrate body 101 and printed (so-called offset printing). FIG. 8 is an explanatory diagram when offset printing is performed in the second solder printing process. A part of the BGA pad 13 is a printed part on which the solder paste 41 is printed, and the exposed part is left exposed. When the metal mask 47 is removed from the second main surface 101b of the substrate body 101 after the solder paste 41 is printed, the second main surface 101b is applied to the surface of the BGA pad 13 and the solder resist layer 15 corresponding to the through holes 45. 41 is printed.
According to this offset printing method, the solder paste flows so as to spread over the entire surface of the BGA pad 13 during reflow, and the air trapped in the solder paste is discharged to the outside along with the flow of the solder paste. The generation of voids can be suppressed. Thereby, generation | occurrence | production of the solder particle by the burst of the void at the time of reflow can be reduced.

Next, a base plate DT1 on which the substrate main body 101 is placed is prepared during heating in the reflow furnace.
FIG. 9 is a perspective view showing the base plate DT1. FIG. 10 is a cross-sectional view illustrating a state in which the base plate DT1 is cut along AA in FIG.
The base plate DT1 is made of stainless steel, has an outer shape of about 400 mm × about 400 mm × about 3 mm, and has the same outer peripheral shape as the substrate body 101. The base plate DT1 includes a frame body portion DTS, a support protrusion DTB, and a connection portion DTW. The frame body portion DTS, the connection portion DTW, and the support protrusion DTB are integrally configured. The base plate DT1 can be created by cutting a stainless steel substrate with a machine.

The frame body portion DTS has a plate shape in a frame shape in which both the outer periphery and the inner periphery are substantially square in a plan view. The outer periphery of the frame body portion DTS coincides with the outer periphery of the substrate body 101, and the inner periphery of the frame body portion DTS is more than the outer periphery of the product portion 115 of the substrate body 101 (that is, the inner periphery of the peripheral edge portion 121 of the substrate body 101). large. Therefore, when the substrate body 101 is placed on the base plate DT1 so that the outer peripheries thereof overlap, the upper surface of the frame body portion DTS comes into contact with the lower surface of the peripheral edge portion 121 of the substrate body 101 and the lower surface of the product portion 115. Does not touch.
The connection portion DTW connects the frame body portion DTS and the support protrusion DTB, and is formed in a lattice shape so as to connect the lower sides of the inner side surface of the frame body portion DTS. The thickness of the connection part DTW is thinner than the thickness of the frame body part DTS.

The support protrusions DTB are hemispherical shapes that are arranged in the openings 150 of the frame body part DTS, respectively, on the intersecting portions of the connection parts DTW formed in a lattice shape, and project upward. The top of the support protrusion DTB has the same height as the top surface of the frame body part DTS. When the substrate main body 101 is placed on the base plate DT1 so that the outer peripheries of the support protrusions DTB overlap each other, the support protrusion DTB makes point contact with the lower surface of the connecting portion 114 of the substrate main body 101 (in other words, the lower surface of the connecting portion 114 is point-supported). ).
As the shape of the support protrusion DTB, from the viewpoint of preventing the occurrence of scratches on the lower surface of the substrate body 101 to be placed, it is preferable that the upper end portion that makes point contact with the lower surface of the substrate body 101 is rounded. For example, the taper shape which rounded the vertex of the cone can be mentioned.
In the present embodiment, the plurality of support protrusions DTB are arranged on the intersecting portions of the lattice-shaped connection portions DTW. However, the support protrusions DTB may be disposed on other portions other than the intersecting portions. Good. From the viewpoint of effectively suppressing the warpage of the substrate body 101 during reflow, it is preferable to disperse and arrange the plurality of support protrusions DTB on the connecting portions 114 of the product portion 115 as in this embodiment.

  The base plate DT1 is provided with the same number of through-holes DTH as the small substrate 117 of the substrate main body 101 (100 (in the figure, 16 simplified)) through which the substrate main body 101 is placed. At the position corresponding to the product part 115 (center part). The through hole DTH is for improving thermal efficiency during reflow. Specifically, each through-hole DTH has a substantially rectangular shape in a plan view of about 32 mm × about 32 mm, is a position corresponding to the small substrate 117 when the substrate body 101 is placed, and has a large number of solder layers 19. A solder layer projection region obtained by projecting the solder layer region to be formed in the thickness direction is formed so as to be positioned in the hole.

  In addition to the stainless steel described above, for example, an aluminum alloy, a magnesium alloy, titanium, or the like may be used as a constituent material of the base plate DT1.

  Next, the substrate body 101 is placed on the base plate DT1 so that the outer peripheries of the substrates overlap (placement process). FIG. 5E shows a state where the substrate body 101 is placed on the base plate DT1. The first main surface 101a of the substrate body 101 on which the solder paste 41 is printed on the surface of the FC pad 11 is placed on the base plate DT1.

  The reason why the first main surface 101a of the substrate body 101 is placed on the base plate DT1 will be described below. Since the solder resist layer 15 has poor solder wettability to the extent that it repels the solder that has flowed out, it functions as a solder resist layer and suppresses the solder from flowing out. However, since the solder bump 18 protrudes from the solder resist layer 15 and is formed over the solder resist layer 15, the solder resist layer 15 may not sufficiently prevent the solder outflow. Therefore, when the first main surface 101a of the substrate main body 101 is placed on the base plate DT1, the solder melted on the surface of the FC pad 11 is dropped or the solder of the adjacent FC pads 11 flows between the solders. Is placed on the base plate DT1 with the first main surface 101a of the substrate body 101 facing up.

  Next, four holding jigs HJ for holding the substrate body 101 on the base plate DT1 are prepared (see FIG. 5F). The holding jig HJ is a U-shaped metal plate made of stainless steel and having a thickness of about 1 mm. Accordingly, the inner surfaces facing each other have a concave groove HJM that is flat. The outer shape of the holding jig HJ is about 6.5 mm in width, about 10 mm in depth, and about 380 mm in length. The recessed groove HJM has a width of about 4.5 mm and a depth of about 9 mm. The holding jig HJ may be made of an aluminum alloy, a magnesium alloy, a heat resistant resin, or the like.

  Next, using the holding jig HJ, the substrate body 101 is fixed in a state of being placed on the base plate DT1 (fixing step). FIG. 5F shows a state in which the holding jig HJ is attached to the substrate body 101 and the base plate DT1. With the substrate body 101 placed on the base plate DT1, the peripheral edge portion 121 of the substrate main body 101 and the frame body portion DTS of the base plate DT1 are inserted into the concave groove HJM of the holding jig HJ, and the peripheral edge portion of the substrate main body 101 The substrate body 101 is fixed on the base plate DT1 by sandwiching the upper surface of 121 and the lower surface of the frame body portion DTS. Specifically, four sides of the peripheral edge portion 121 and the frame body portion DTS are inserted together into the concave groove HJM of the holding jig HJ.

  In the present embodiment, most of the outer periphery of the substrate body 101 is inserted into the holding jig HJ and fixed to the base plate DT1, but it is not necessary to be the most outer periphery, and is a part of the outer periphery. Also good. This is because even when only a part of the outer periphery is inserted into the holding jig HJ, it is possible to suppress warping of the substrate body 101 during heating.

Thereafter, in the reflow process, the substrate main body 101 having both sides solder-printed is reflowed with the first main surface 101a of the substrate main body 101 having the solder paste 41 printed on the surface of the FC pad 11 as shown in FIG. 5G. Heat in a furnace.
FIG. 11 is an explanatory diagram showing a state in which the substrate body 101 and the base plate HJ with the holding jig HJ are placed in the reflow furnace RF. The substrate body 101 is transported on a transport chain (support member) SJ arranged in two rows at a predetermined interval. Specifically, the substrate body 101 and the base plate DT1 to which the substrate body 101 is placed on the upper side and the holding jig HJ is attached are transported while being erected on the protrusions of the transport chain SJ. In this state, the substrate body 101 is placed in the reflow furnace RF, and the solder paste 41 is heated and reflowed to form the solder bumps 18 for flip chip mounting on the surface of the FC pad 11, and the solder balls on the BGA pad 13. A solder layer 19 for attachment is formed. During this reflow, the solder paste 41 is well spread over the entire surface of the pads 11 and 13 by removing the oxide film on the surfaces of the pads 11 and 13 in the cleaning step, and the solder bumps 18 and the solder layer 19 having the above-described structure are formed. Form.

A large number of wiring boards 1 can be obtained at a time by cutting the substrate body 101 provided with solder layers (solder bumps 18, solder layers 19) for each small substrate 117.
The wiring board 1 is completed through the above steps.

  Note that the solder bumps 18 are melted on the FC pad 11 of the wiring board 1 manufactured in this manner in a state where an IC chip (not shown) is placed by a well-known technique. Bonded to the FC pad 11. In addition, the solder layer 19 is dissolved in a state in which a solder ball (not shown) is placed on the BGA pad 13 of the wiring board 1, whereby the solder ball is bonded to the BGA pad 13. At the same time, the solder balls are joined to input / output terminals such as a mother board (not shown), whereby the wiring board 1 is joined to the mother board or the like.

  According to the method for manufacturing the wiring substrate 1 of the present embodiment, the following advantages (effects) can be obtained.

In the manufacturing method of the present embodiment, the peripheral edge 121 of the substrate main body 101 is fixed to the frame body DTS of the base plate DT1 by the holding jig HJ. Therefore, it is possible to suppress warping of the substrate body 101 in the reflow process. As a result, the co-polarity of the solder bump 18 and the BAG pad 13 is improved, so when each terminal of the IC chip is connected to the solder bump 18 or when another board such as a motherboard is connected to the BAG pad 13, Connection failure can be suppressed. As shown in FIG. 16, in general, a conventional substrate body heated in a reflow furnace tends to be deformed so that the peripheral edge portion faces upward. On the other hand, in this embodiment, since the peripheral part 121 of the board | substrate body 101 is being fixed to the frame part DTS with the holding jig HJ, the curvature of the board | substrate body 101 can be suppressed.
Further, since the support protrusion DTB of the base plate DT1 supports the connecting portion 114 of the substrate main body 101 from below, it is possible to further suppress the warpage of the substrate main body 101 in the reflow process.

Further, even when the substrate main body 101 is fixed to the base plate DT1 at a position deviated from the planned placement position and the upper end of the support protrusion DTB contacts the lower surface of the small substrate 117, the support protrusion DTB of the base plate DT1. Supports the lower surface of the substrate body 101 with dots. Therefore, since the contact area between the base plate DT1 and the lower surface of the small substrate 117 is small, it is possible to suppress the occurrence of scratches over a wide range. Thereby, it is possible to improve the manufacturing yield of the wiring board 1.
Further, the support protrusions DTB are distributed and arranged only on the intersecting portions of the connection portions DTW formed in a lattice shape. Therefore, since the total contact area between the plurality of support protrusions DTB and the product portion 115 of the substrate body 101 is small, the occurrence of scratches on the lower surface of the small substrate 117 can be reduced. Thereby, it is possible to further improve the manufacturing yield of the wiring board 1.
Further, since the support protrusion DTB has a hemispherical shape and the upper end portion that makes point contact with the lower surface 101b of the substrate body 101 is rounded, the occurrence of scratches on the lower surface 101b (the lower surface of the small substrate 117) of the substrate body 101 is prevented. be able to. Thereby, it is possible to further improve the manufacturing yield of the wiring board 1.

  In the present embodiment, the solder layer disposed on the surface of the BGA pad 13 when the solder bump 18 and the solder layer 19 are formed in the reflow process so that the second main surface 101b of the substrate main body 101 is located downward. 19 is formed lower than the height of the solder resist layer 15. Therefore, it is possible to prevent the molten solder from flowing out and dripping from the surface of the BGA pad 13 to the outside of the recess 17. Since the solder resist layer 15 has poor solder wettability to the extent that the solder that has flowed out is repelled, the solder resist layer 15 functions as a solder resist layer and suppresses the outflow of solder. Since the solder layer 19 is formed lower than the height of the solder resist layer 15, the solder resist layer 15 functions as a solder resist layer, and the outflow of solder to the outside of the recess 17 can be suppressed.

  In the present embodiment, the surface of the BGA pad 13 is cleaned in the cleaning process to remove the oxide film and improve the wettability of the solder. Therefore, it is possible to prevent the solder paste 41 on the surface of the BGA pad 13 printed on the lower surface side of the substrate body 101 from being heated and melted during the reflow process, and the solder flowing out of the recesses 17 or dripping down. can do.

Further, in the present embodiment, the support protrusion DTB of the base plate DT1 supports the product portion 115 of the placed substrate body 101 with a point, and on the intersecting portion of the connection portions DTW formed in a lattice shape. Are distributed. Therefore, the total contact area between the base plate DT1 and the product portion 115 of the substrate body 101 is small. As a result, during the reflow process, the molten solder that has temporarily flowed out of the recess 17 from the surface of the BGA pad 13 on the lower surface of the substrate body 101 comes into contact with the base plate DT1 having high solder wettability, thereby It can be suppressed from flowing out.
Further, since the total contact area between the base plate DT1 and the product portion 115 of the substrate main body 101 is small, the case where the substrate main body 101 is fixed to the base plate DT1 at a position deviated from the intended placement position or the second solder printing is performed. Even when offset printing is performed in the process, it is possible to suppress the solder melted on the lower surface (second main surface 101b) of the substrate body 101 from coming into contact with the base plate DT1 having high solder wettability and flowing out through the base plate DT1.

  In the present embodiment, as described above, during the reflow process, the solder paste 41 printed on the lower surface side (second main surface 101b) of the substrate main body 101 is heated and melted to the outside of the recess 17. Solder can be prevented from flowing out or dripping down. As a result, solder layers (solder bumps 18 and solder layers 19) can be formed on both sides of the substrate body 101 with a single heating, so that the productivity of the wiring substrate 1 can be improved and the manufacturing cost can be reduced. Thermal degradation of the wiring board 1 can be suppressed.

In the present embodiment, a nickel plating layer that is generally formed in the method of manufacturing a wiring board is not formed on the FC pad 11 and the BGA pad 13. Therefore, when flip chip mounting or solder ball mounting, nickel diffuses inside the solder, and a brittle nickel-tin intermetallic compound is formed at the boundary between the nickel plating layer and the solder (solder bump 18 or solder layer 19). Can be prevented. As a result, the bonding strength between the IC chip and the FC pad 11 or between the solder ball and the BGA pad 13 can be improved.
In this embodiment, since the solder bumps 18 are formed on the FC pads 11 and the solder layer 19 is formed on the BGA pads 13, the oxidation of the surfaces of the pads 11 and 13 can be effectively suppressed.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 12 is a perspective view showing the base plate DT2 used in the present embodiment. Portions common to FIG. 9 are denoted by the same reference numerals, and redundant description is omitted.

  The manufacturing method of the wiring board 1 of this embodiment is different from that of the first embodiment in that the base plate made of the frame body portion DTS is placed on the base plate on which the substrate body 101 is placed in the reflow process (including the placement process and the placement process). The difference is that the plate DT2 is used.

  According to the method for manufacturing the wiring substrate 1 of the present embodiment, the following advantages (effects) can be obtained.

In the manufacturing method according to the present embodiment, even when the substrate body 101 is fixed to the base plate DT2 at a position shifted from the intended placement position, the base plate DT2 is configured only by the frame body portion DTS. There is no part in contact with the lower surface of the product part 115 of 101. Therefore, contact between the base plate DT2 and the lower surface of the product portion 115 can be reliably prevented. As a result, it is possible to prevent the lower surface of the small substrate 117 of the substrate body 101 from being scratched, and to improve the yield of the wiring substrate 1.
Further, in this embodiment, since the base plate DT2 and the lower surface of the product portion 115 do not come into contact with each other, scratches on the lower surface of the small substrate 117 occur, and the lower surface (second main surface 101b) of the substrate body 101 is heated and melted in the reflow process. Thus, it is possible to reliably prevent the solder that has flowed through the base plate DT2. Therefore, the width of the connecting part of the product part of the board main body can be narrowed, or the small board can be arranged without a gap without providing the connecting part, so that more small boards can be arranged in the board main body, and the wiring board It is possible to further improve the yield of 1.
Further, in the present embodiment, since the contact between the base plate DT2 and the lower surface of the product portion 115 can be reliably prevented, the solder melted on the lower surface (second main surface 101b) of the substrate body 101 in the reflow process becomes the base plate DT2. Can be surely prevented from flowing out through. Therefore, it is easy to suppress the generation of voids in the solder layer 19 by performing offset printing in the second solder printing process.

  Also in the manufacturing method of the present embodiment, since the peripheral portion 121 of the substrate body 101 is fixed to the frame body portion DTS by the holding jig HJ, as described above, the warpage of the substrate body 101 in the reflow process is suppressed. Can do.

Also in this embodiment, when forming the solder bumps 18 and the solder layer 19 in the reflow process, the solder layer 19 disposed on the surface of the BGA pad 13 on the lower surface of the substrate body 101 is made lower than the height of the solder resist layer 15. Forming. In addition, the oxide film is removed by cleaning the surface of the BGA pad 13 in the cleaning process to improve the wettability of the solder. Further, the base plate DT2 does not come into contact with the product portion 115 of the substrate body 101, and the solder melted on the lower surface (second main surface 101b) of the substrate body 101 comes into contact with the base plate DT2 having high solder wettability. It is prevented from flowing out through DT2.
Therefore, as described above, during the reflow process, the solder paste 41 on the surface of the BGA pad 13 printed on the lower surface side of the substrate main body 101 is melted, and the solder flows out or droops out of the recess 17. Can be suppressed. As a result, solder layers (solder bumps 18 and solder layers 19) can be formed on both sides of the substrate body 101 with a single heating, so that the productivity of the wiring substrate 1 can be improved and the manufacturing cost can be reduced. Thermal degradation of the wiring board 1 can be suppressed.

Also in this embodiment, no nickel plating layer is formed on the FC pad 11 and the BGA pad 13. Therefore, as described above, the bonding strength between the IC chip and the FC pad 11 or the solder ball and the BGA pad 13 can be improved.
Also in this embodiment, since the solder bumps 18 are formed on the FC pad 11 and the solder layer 19 is formed on the BGA pad 13, the oxidation of the surfaces of the pads 11 and 13 can be effectively suppressed.

(Modification)
In the manufacturing methods of the first and second embodiments described above, the printing process of printing the solder paste 41 directly on the FC pad 11 and the BGA pad 13 is performed after the cleaning process, and the solder bumps 18 and the solder layer 19 are formed through the reflow process. Forming.
On the other hand, after the cleaning process, Au plating is directly applied to the FC pad 11 and the BGA pad 13 in the Au plating process to form an Au plating layer (for example, 20 nm to 200 nm). Alternatively, the process may be shifted to a printing process in which the solder paste 41 is directly screen-printed (ie, solder-printed) on the Au layer.

  By forming the Au layer in this manner, it is possible to effectively suppress the oxidation of the surfaces of the copper pads 11 and 13 that are easily oxidized during the process after the Au plating process. Therefore, by suppressing this oxidation, it becomes possible to form solder layers (solder bumps 18 and solder layers 19) on the surfaces of the FC pad 11 and the BGA pad 13 with the solder wettability improved. As a result of improving the solder wettability, the solder paste 41 on the surface of the BGA pad 13 printed on the lower surface side of the substrate body 101 is melted during the reflow process, and the solder flows out or droops out of the recess 17. Can be further suppressed. Further, since the Ni plating layer is not formed as in the prior art, it is necessary to effectively secure the bonding properties such as the bonding strength between the pads (FC pads 11 and BGA pads 13) and the solder layers (solder bumps 18 and 19). Is possible.

  In addition, since the layer thickness of the Au layer is, for example, about 20 nm to 200 nm, after the solder layer is formed by reflow, the Au layer itself disappears due to excessive flow of Au, or the surfaces of the pads 11 and 13 are removed. In some cases, the Au layer remains only in a partially covered form. Even in such a case, the effect of not forming the Ni plating layer as in the past and the main purpose of forming the Au layer are to suppress the oxidation of the pad surface until the solder layer is formed. Itself can function as well

  In the above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.

  For example, in the above embodiment, the substrate main body 101 is placed on the base plates DT1 and DT2 with the second main surface 101b of the substrate main body 101 facing the base plates DT1 and DT2, but printing is performed on the surface of the pad 11, for example. When the flow of molten solder or dripping from the surface of the pad 11 can be suppressed due to a small amount of solder paste applied, the first main surface 101a faces the base plates DT1 and DT2, and the substrate body 101 can be mounted on the base plates DT1 and DT2.

  Further, when the width of the concave groove HJM of the holding jig HJ is extremely wider than the combined thickness of the substrate body 101 and the base plates DT1, DT2, stainless steel, aluminum alloy, magnesium alloy, heat resistant resin, etc. The peripheral portion 121 of the substrate body 101 and the peripheral portion DTS of the base plates DT1 and DT2 may be held with a spacer (flat plate) made of Even if it takes such a form, the curvature which arises in substrate body 101 can be controlled.

  In the above embodiment, the solder layer (solder bump 18 or solder layer 19) is formed on both the pads 11 and 13. However, the solder layer may be formed only on the pad 11 or only on the pad 13. .

  Further, eutectic solder such as Sn—Ag or Sn—Ag—Cu may be used for the solder bump 18 and the solder layer 19.

It is a top view showing the composition of the 1st principal surface of the wiring board concerning the embodiment of the present invention. It is a top view showing the structure of the 2nd main surface of the wiring board which concerns on embodiment of this invention. It is sectional drawing which represents roughly the structure of the cross section of the wiring board which concerns on embodiment of this invention. It is a general | schematic expanded sectional view showing the cross-sectional structure of the BGA pad periphery formed in the 2nd main surface of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is explanatory drawing showing the manufacturing process of the wiring board which concerns on embodiment of this invention. It is a perspective view which simplifies and shows the substrate main body concerning the embodiment of the present invention. It is explanatory drawing which expanded and represented the structure of the BGA pad surface at the time of printing of solder paste. It is explanatory drawing at the time of performing offset printing in the 2nd solder printing process. It is a perspective view showing the baseplate which concerns on the 1st Embodiment of this invention. It is sectional drawing showing the state which cut | disconnected the baseplate which concerns on the 1st Embodiment of this invention along AA of FIG. It is explanatory drawing which shows a mode that the baseplate which attached the holding jig and the baseplate which concerns on embodiment of this invention were put into the reflow furnace. It is a perspective view showing the baseplate which concerns on the 2nd Embodiment of this invention. It is a perspective view showing the baseplate which concerns on a prior art form. It is a perspective view which simplifies and shows the board | substrate body which concerns on a prior art form. It is explanatory drawing which shows the state which attached the holding jig to the board | substrate body and base plate which concern on a prior art form. It is explanatory drawing which shows the mode of the board | substrate body after manufacture regarding the manufacturing method of the wiring board which concerns on a prior art form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board, 11 ... Pad (FC pad), 13 ... Pad (BGA pad), 18 ... Solder bump, 19 ... Solder layer, 101 ... Substrate body, 101a ... First main surface, 101b ... Second main surface, 114 ... Connecting part, 115 ... Product part, 117 ... Small substrate, 121 ... Peripheral part, 150 ... Opening, DT1, DT2 ... Base plate, DTS ... Frame body part, DTB ... Support protrusion, DTW ... Connection part, DTH ... Through hole , HJ: holding jig, HJM: concave groove, SJ: support member.

Claims (3)

Solder paste on a pad disposed on the small substrate of the substrate body having a product portion having a plurality of small substrates and a connecting portion for connecting the plurality of small substrates, and a peripheral portion located at the periphery of the product portion An application process of applying
An upper surface of the frame body and the peripheral edge are provided on a base plate having a frame body, a support protrusion disposed in the opening of the frame body, and a connecting portion that connects the support protrusion and the frame body. A placing step of placing the substrate body such that the lower surface of the part abuts and the support protrusions point-support the connection part from below;
Using a holding jig having a concave groove, the peripheral portion of the substrate main body and the frame body portion of the base plate are inserted into the concave groove of the holding jig while the substrate main body is placed on the base plate. And fixing step of fixing the substrate body to the base plate by sandwiching the upper surface of the peripheral portion and the lower surface of the frame body portion,
A heating step of heating the substrate body fixed to the base plate;
A method for manufacturing a wiring board, comprising: An application step of applying a solder paste on a pad disposed on the product part of the substrate body having a product part and a peripheral part located at a peripheral part of the product part;
A placing step of placing the substrate body such that an upper surface of the frame body part and a lower surface of the peripheral edge part abut on a base plate made of a frame body part;
Using a holding jig having a concave groove, the peripheral part of the substrate main body and the frame body part are inserted into the concave groove of the holding jig while the substrate main body is placed on the base plate. A fixing step of fixing the substrate body to the base plate by sandwiching an upper surface of a peripheral portion and a lower surface of the frame body portion;
A heating step of heating the substrate body fixed to the base plate;
A method for manufacturing a wiring board, comprising:   A first pad disposed on the first main surface of the substrate body; and a second pad disposed on a second main surface opposite to the first main surface of the substrate body. The method for manufacturing a wiring board according to claim 1, comprising:

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