JP2018125508A - Multi-piece wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-piece wiring board where a foreign object is not left on joint surfaces bonded with each other.SOLUTION: A multi-piece wiring board 100 where a plurality of product regions 11 to become small-sized wiring boards each having a multiple electronic element connection pads 17 to be electrically connected with electrodes of an electronic element on one principal surface and a multiple external connection pads 18 to be connected with connection conductors of an electric circuit board via solders on another principal surface, are arranged in large-sized substrates 10A, 10B and integrally formed with the large-sized substrate 10A, 10B together with a waste region 12 to be cut off around each product region 11, two large-sized substrates 10A, 10B are arranged in such a manner as to face the other principal surfaces with each other and the waste regions 12 are joined to each other by an adhesive 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-piece wiring board in which a plurality of product regions that are small wiring boards for mounting electronic elements such as semiconductor integrated circuit elements are integrally arranged in a large board.

  2. Description of the Related Art Conventionally, a multi-piece wiring board has been used as a form for simultaneously handling a plurality of small wiring boards for mounting electronic elements such as semiconductor integrated circuit elements.

  This multi-cavity wiring board is formed by integrally arranging a product area that becomes a large number of small wiring boards in a single large board with a margin area around it.

  In this multi-cavity wiring board, an electronic element such as a semiconductor integrated circuit element is mounted in each product region via, for example, a solder bump, and the electronic element is resin-sealed by, for example, a transfer molding method. By cutting along the outer periphery of the product area, a large number of electronic devices in which electronic elements are mounted on a small wiring board are simultaneously and collectively manufactured.

  However, recently, with the demand for thinning of electronic devices, multi-cavity wiring boards used for mounting electronic elements have also been thinned. Therefore, the multi-cavity wiring board is likely to be greatly bent by a slight force, and the multi-cavity wiring board is used when mounting an electronic element in each product area or when sealing the mounted electronic element. Since it cannot be kept flat, it has become difficult to mount electronic elements and perform resin sealing well.

  Therefore, a method has been proposed in which two multi-piece wiring boards are mounted and resin-sealed with an electronic element in a state where the back surfaces opposite to the side on which the electronic element is mounted are bonded to each other with an adhesive tape. .

  However, according to this method, when the adhesive tape is peeled off after mounting the electronic element, there is a high risk that a part of the adhesive of the adhesive tape remains as a foreign substance on the back surface of the electronic device.

JP 2007-180305 A

  The problem to be solved by the present invention is to provide a multi-piece wiring board in which no foreign matter remains on the bonded surfaces bonded to each other.

  The multi-cavity wiring board of the present invention has a large number of electronic element connection pads to which electrodes of electronic elements are connected on one main surface, and is connected to the other main surface via a connection conductor of an electric circuit board via solder. A plurality of product areas to be a small wiring board having a large number of external connection pads are integrally arranged in a large board with a margin area cut and removed around each product area. It is a multi-piece wiring board, and the two large substrates are arranged with the other main surfaces facing each other, and the discard margin regions on the other main surfaces facing each other are made of adhesive. It is characterized by being joined via.

  According to the multi-cavity wiring board of the present invention, product regions that are small wiring boards having electronic element connection pads on one main surface and many external connection pads on the other main surface are integrally formed. The two large substrates are arranged with the other main surfaces facing each other, and the discard margin regions on the other main surfaces facing each other are joined together via an adhesive, so that the other When the main surfaces are separated from each other, the adhesive does not remain as foreign matter on the external connection pads in each product region.

FIG. 1 is a schematic sectional view showing an embodiment of a multi-piece wiring board according to the present invention. FIG. 2 is a schematic cross-sectional view for explaining a method of manufacturing the multi-cavity wiring board shown in FIG. FIG. 3 is a schematic cross-sectional view for each step for explaining an example of a method for manufacturing an electronic device using the embodiment of the multi-cavity wiring board of the present invention. FIG. 4 is a schematic cross-sectional view showing another example of the embodiment of the multi-cavity wiring board of the present invention. FIG. 5 is a schematic cross-sectional view for each process for explaining a method for manufacturing an electronic device using another example of the embodiment of the multi-cavity wiring board according to the present invention. FIG. 6 is a schematic plan view showing a preferred example of the embodiment of the multi-piece wiring board according to the present invention. FIG. 7 is a schematic cross-sectional view showing another preferred example in the embodiment example of the multi-cavity wiring board of the present invention. FIG. 8 is a schematic cross-sectional view showing still another preferred example of the embodiment of the multi-cavity wiring board according to the present invention.

  FIG. 1 shows an embodiment of a multi-cavity wiring board according to the present invention. In FIG. 1, 10A and 10B are large substrates, and 20 is an adhesive. The large-sized substrate 10A, 10B is bonded through the adhesive 20, whereby the multi-piece wiring substrate 100 of this example is formed.

  The large substrates 10A and 10B have a rectangular flat plate shape. In the large substrates 10A and 10B, a large number of product regions 11 are integrally formed with a margin region 12 around them. The product region 11 is a region that becomes a small wiring board on which the electronic element E is mounted. The disposal allowance area 12 is an area necessary for manufacturing and handling the large substrate 10 and is a part that is finally discarded.

  The large substrates 10A and 10B are formed by alternately laminating a plurality of insulating layers 13 and conductor layers 14 and depositing a solder resist layer 15 on the outermost surface thereof.

  The insulating layer 13 is made of, for example, a thermosetting resin containing glass cloth. As the thermosetting resin, epoxy resin, bismaleimide triazine resin, or the like is used. The thickness of the insulating layer 13 is about 15 to 50 μm. A plurality of via holes 16 are formed in each insulating layer 13. The diameter of the via hole 16 is about 30 to 100 μm.

  The conductor layer 14 is deposited on the surface of each insulating layer 13 and the inside of the via hole 16. The conductor layer 14 is made of, for example, copper. The thickness of the conductor layer 14 deposited on the surface of each insulating layer 13 is about 5 to 25 μm. The conductor layer 14 completely fills each via hole 16.

  The solder resist layer 15 is made of a photosensitive thermosetting resin. As the photosensitive thermosetting resin, for example, an acrylic-modified epoxy resin or the like is used. The thickness of the solder resist layer 15 is about 10 to 30 μm.

  A large number of electronic element connection pads 17 are formed on one main surface of each product region 11. The electronic element connection pad 17 is formed by a part of the conductor layer 14. The electronic element connection pad 17 is circular. The diameter of the electronic element connection pad 17 is about 50 to 150 μm. The electronic element connection pad 17 is exposed from the solder resist layer 15. The electrode of the electronic element E is connected to the electronic element connection pad 17 via solder.

  A large number of external connection pads 18 are formed on the other main surface of each product region 11. The external connection pad 18 is formed by a part of the conductor layer 14. The external connection pad 18 is circular. The diameter of the external connection pad 18 is about 200 to 800 μm. The external connection pad 18 is exposed from the solder resist layer 15. The external connection pad 18 is connected to a connection conductor of an electric circuit board (not shown) such as a mother board via solder.

  In the solder resist layer 15 on the other main surface of the disposal margin region 12, openings 19 are formed at positions facing each other. The diameter of the opening 19 is about 50 to 1000 μm. In the opening 19, the large substrates 10 </ b> A and 10 </ b> B are bonded via an adhesive 20.

  The adhesive 20 is made of a thermosetting resin such as an epoxy resin. The adhesive 20 joins the disposal margin regions 12 on the other main surfaces of the large substrates 10 </ b> A and 10 </ b> B in the opening 19 of the solder resist layer 15. Thereby, the two large substrates 10A and 10B are joined to each other in a state where the solder resist layers on the other main surface are in contact with each other. As described above, since the two large substrates 10A and 10B are joined to each other while being in contact with each other, a gap may be formed between the two large-sized substrates 10A and 10B even though they are joined only by the disposal allowance region 12. Absent.

  Thus, since the multi-piece wiring board 100 of this example has two large-sized boards 10A and 10B joined together via the adhesive 20, the rigidity that is difficult to bend with a slight force is given. Yes. In addition, the two large substrates 10A and 10B are bonded in a state where the solder resist layers 15 on the other main surface are in contact with each other, so that when mounting the electronic element E or sealing the resin, It is possible to effectively prevent the slight bending caused by the gap.

  Next, a method of manufacturing an electronic device in which the electronic element E is mounted on a small wiring board using the multi-piece wiring board 100 of this example will be described.

  First, as shown in FIG. 1, the multi-piece wiring board 100 and the electronic element E of this example are prepared. As shown in FIG. 2 (a), the multi-piece wiring board 100 prepares two large substrates 10A and 10B individually, and, as shown in FIG. Obtained by joining. The adhesive 20 is preferably applied in advance to at least one of the large substrates 10A and 10B.

  Next, as shown in FIG. 3A, the electronic element E is mounted on each product region 11 of the large substrate 10 and resin-sealed with a mold resin R. At this time, the multi-piece wiring board 100 of this example has two large substrates 10A and 10B joined together via the adhesive 20 and is not easily bent, so that the mounting of the electronic element E and the resin sealing are good. It can be carried out.

Next, as shown in FIG. 3B, the assembly in which the electronic element E is mounted on the multi-piece wiring board 100 is cut along the boundary of each product region 11. As a result, each product region 11 and the mold resin R corresponding thereto are divided into individual pieces, and a large number of electronic devices in which the electronic elements E are mounted on a small wiring board are simultaneously and collectively manufactured. In addition, a dicer or a router is used for cutting. At this time, an adhesive tape or the like may be attached to the surface of the mold resin R in order to prevent the product divided into individual pieces from being scattered.

  At this time, since the large substrates 10A and 10B are joined to each other only in the disposal allowance region 12, the adhesive 20 does not remain as a foreign substance in the separated product region 11. Therefore, according to the multi-cavity wiring board 100 of this example, it is possible to provide the multi-cavity wiring board 100 in which no foreign matter remains on the bonded surfaces bonded to each other.

  In the above-described embodiment, the large substrates 10A and 10B are joined via an adhesive made of an epoxy resin. However, the large substrates 10A and 10B may be joined via an adhesive other than the epoxy resin. As shown in FIG. 4, bonding may be performed via solder 30. In this case, as shown in FIG. 5A, after the electronic element E is mounted on each product region 11 of the large substrates 10A and 10B and sealed with the mold resin R, as shown in FIG. 5B. Then, the large substrates 10A and 10B are separated, and then the large substrates 10A and 10B and the mold resin R are cut along the boundaries of the product regions 11 as shown in FIG. May be.

  Further, as shown in a plan view of the large substrates 10A and 10B viewed from the lower surface side in FIG. 6, slits S for stress relaxation may be provided in the disposal margin region 12 in the large substrates 10A and 10B. By providing such a slit S, thermal stress generated when the large substrates 10A and 10B are joined to each other or when the electronic element E is mounted on the large substrates 10A and 10B is absorbed and relaxed by the slit S. It is possible to more effectively prevent the warpage of the individual wiring substrate 100 from occurring.

  Such a slit S is preferably a long hole shape along each side of the outer periphery of each product region 11. The width of the slit S is, for example, about 50 to 500 μm. The slit S is formed by, for example, router processing or laser processing. The slit S is completely included in the portion to be cut or completely removed from the portion to be cut when the large substrates 10A and 10B and the mold resin R are cut along the boundaries of the respective product regions 11. It is preferable to form it like this. Thereby, the escape of the cutting blade due to the presence of the slit S can be prevented and cutting can be performed accurately.

  Furthermore, as shown in FIG. 7 and FIG. 8, a resin injection hole H may be provided in a portion where the two large substrates 10A and 10B are joined via the adhesive 20. By providing such a resin injection hole H, the large substrates 10A and 10B can be easily joined to each other by injecting the adhesive 20 from the resin injection hole H. Further, by accommodating the excess adhesive 20 in the resin injection hole H, it is possible to satisfactorily prevent the adhesive 20 from protruding in the horizontal direction.

  As shown in FIG. 7, when the resin injection hole H is provided only in one of the large substrates 10A and 10B, a positioning mark M corresponding to the resin injection hole H is provided on the surface of the other large substrate 10A or 10B, for example, a conductor layer. If the positioning marks M and the resin injection holes H are aligned, the large substrates 10A and 10B can be joined with high accuracy. Further, as shown in FIG. 8, when the resin injection holes H are provided in both of the large substrates 10A and 10B, the large substrates 10A and 10B can be accurately joined by aligning the resin injection holes H. it can.

10A, 10B Large substrate 11 Product area 12 Discard allowance area 17 Electronic element connection pad 18 External connection pad 19 Temporary pad 20 Adhesive E Electronic element H Resin injection hole S Slit

Claims (4)

  A small size having a large number of electronic element connection pads connected to the electrodes of the electronic element on one main surface and a large number of external connection pads connected to the connection conductors of the electric circuit board via solder on the other main surface A plurality of product areas which are integrally formed in a large-sized substrate with a margin area to be cut and removed around each product area, The large substrates are arranged with the other main surfaces facing each other, and the discard margin regions on the other main surfaces facing each other are bonded together with an adhesive. Multi-cavity wiring board.   A solder resist layer having openings facing each other is attached to the abandon margin region on the other opposing main surface, and the bonding is performed in the openings in a state where the solder resist layers facing each other are in contact with each other. The multi-cavity wiring board according to claim 1, wherein an agent is accommodated.   The multi-cavity wiring board according to claim 1 or 2, wherein a slit along the outer periphery of each product area is formed in the discard margin area.   The resin injection hole penetrating at least one of the two large substrates is formed in a portion bonded through the adhesive, wherein a plurality of resin injection holes according to any one of claims 1 to 3 are provided. Wiring board.