JP2009267061A - Method of manufacturing wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a wiring board which prevents the formation of a burr or an elongation on a metal heat sink and enables manufacturing the thin wiring board having the metal heat sink reduced in thickness. <P>SOLUTION: The method is provided for manufacturing the wiring board including a wiring board body 3 having a through-hole C at its center for housing a semiconductor device S and the metal heat sink 5 joined to the undersurface of the wiring board body 3 to close the through-hole C. The manufacturing method includes a step of integrally arranging a plurality of wiring board bodies 3 in a mother substrate 10 such that the wiring board bodies are lined up vertically and horizontally with cutting areas A interposed on boundaries thereof, a step of bonding a metal foil 5P to the undersurface of the mother substrate 10 to cover the wiring board bodies 3 and the cutting areas A, a step of removing the areas corresponding to the cutting areas A by etching from the metal foil 5P, and a step of cutting the mother substrate 10 along the cutting areas A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a wiring board for mounting a semiconductor element, and more specifically, a wiring conductor in which an electrode of the semiconductor element is connected to an upper surface of an insulating substrate having a through hole that accommodates the semiconductor element in a central portion. A method of manufacturing a wiring board comprising: a wiring board main body comprising a wiring board; and a heat sink that is bonded to a lower surface of the wiring board main body so as to close the opening, and on which an upper surface of the opening is mounted with a semiconductor element. It is about.

  2. Description of the Related Art Conventionally, as a wiring board on which a semiconductor element such as a semiconductor integrated circuit element is mounted, as shown in FIG. 2, a plurality of insulating plates in which a glass cloth base material is impregnated with a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin A copper foil or a copper plating in which the electrodes of the semiconductor element S are electrically connected from the upper surface to the lower surface of the insulating substrate 1 having a through hole C for accommodating the semiconductor element S in the center. The wiring board main body 3 on which the wiring conductor 2 composed of layers is disposed is bonded to the lower surface of the wiring board main body 3 via the adhesive layer 4 so as to close the through hole C, and is exposed to the inside C of the through hole. There is known a wiring board including a metal heat radiating plate 5 made of a copper plate on which a semiconductor element S is mounted.

  The wiring board has a through hole 6 formed with a through hole plating conductor for connecting the upper and lower wiring conductors 2 from the upper surface to the lower surface of the wiring board body 3. Is filled with a hole-filling resin 7 made of a thermosetting resin. Further, a part of the hole filling resin 7 covers the upper surface of the insulating substrate 1 and a part of the wiring conductor 2 on the surface thereof to form a resist layer, and the lower surface of the insulating substrate 1 and the wiring conductor 2 on the surface thereof are similarly heated. It is covered with a resist layer 8 made of a curable resin.

  In this wiring board, the semiconductor element S is mounted on the upper surface of the metal heat dissipating plate 5 exposed in the through hole C via the adhesive 9 and the electrode of the semiconductor element S and the wiring conductor 2 are connected via the bonding wire W. After the connection, a sealing resin (not shown) is deposited on the upper surface in and around the through hole C so as to cover the semiconductor element S and the bonding wire W, thereby obtaining a semiconductor device as a product.

  By the way, in order to join the metal heat radiating plate 5 to the wiring board body 3 in such a wiring board, the following method has been conventionally employed. First, as shown in FIG. 3A, a plurality of wiring board main bodies 3 are interposed in a mother board 10 having a size including a plurality of wiring board main bodies 3, and a cutting area A is interposed at the boundary of each area. In this way, the array is formed vertically and horizontally. Next, as shown in FIG. 3B, the cutting area A of the mother board 10 is cut and removed by using a cutting device such as a dicing machine or a router to separate the plurality of wiring board main bodies 3 into individual pieces. Next, as shown in FIG. 3 (c), a metal heat radiating plate 5 made of copper is provided on the lower surface of the wiring board main body 3 as a single piece through an adhesive layer 4 containing a thermosetting resin such as an epoxy resin. Join.

  In such a conventional method, since the metal heat sink 5 is individually joined to the wiring board main body 3 which became a piece, its manufacturing efficiency is inferior. Therefore, in Patent Document 1, as shown in FIG. 4 (a), a plurality of wiring board main bodies 3 are formed in a mother board 10 in a vertically and horizontally integrated manner with a cutting region A interposed at the boundary between them. In this state, a copper plate 5P having a size that simultaneously covers the plurality of wiring boards 3 and the cutting area A is bonded to the lower surface of the mother board 10 via the adhesive layer 4P, and then, as shown in FIG. The cutting area A of the mother board 10 and the boundary area between the copper plate 5P and the adhesive layer 4P that overlaps the cutting area A are cut and removed by using a cutting device such as a dicing machine or a router, and the metal heat sink 5 is attached to the wiring board main body 3. A method of separating a plurality of wiring boards joined via 4 into individual pieces has been proposed.

However, if the mother board 10 and the copper plate 5P overlap with each other in this manner, there is a problem that burrs and elongation occur in the cut copper plate 5P. Therefore, Patent Document 2 proposes a technique in which a slit is provided in advance in a portion corresponding to the cutting region A of the copper plate 5P. However, when a slit is provided in the copper plate 5P, particularly when the copper plate 5P is thin, the mechanical strength of the copper plate 5P is reduced, and the copper plate 5P is distorted or deformed to form each wiring board body 3 formed on the mother board 10. And the copper plate 5P are difficult to accurately align and join. Furthermore, even when the slits are provided in this way, the copper plate 5P is connected at, for example, a portion corresponding to the corner of each wiring board body 3, so that it is completely possible to prevent burrs and elongation from occurring on the copper plate 5P. It cannot be prevented.
Japanese Patent Laid-Open No. 7-3150 JP 2006-10098 A

  The present invention has been devised in view of such problems, and the problem is that it is possible to efficiently join the wiring board body and the metal heat sink, and burrs and stretches occur in the metal heat sink. It is another object of the present invention to provide a method for manufacturing a wiring board that can manufacture a thin wiring board having a thin metal heat sink.

In the method for manufacturing a wiring board according to the present invention, a wiring board in which a wiring conductor to which an electrode of the semiconductor element is electrically connected is disposed on an upper surface of an insulating substrate having a through hole for accommodating a semiconductor element in the center. A method of manufacturing a wiring board, comprising: a main body; and a metal heat radiating plate that is joined to a lower surface of the wiring board main body so as to close the through hole and on which an upper surface is exposed in the through hole. In the mother board having a size including a plurality of the wiring board main bodies, a plurality of the wiring board main bodies are integrally arranged vertically and horizontally with a cutting region at the boundary of the wiring board main bodies. A step of forming, a step of bonding a metal foil serving as the metal heat sink so as to cover the wiring board main body and the cutting region on the lower surface of the mother substrate, and etching a region corresponding to the cutting region in the metal foil Remove And step is the mother substrate which is characterized in that it comprises a step of cutting in the cutting region.
Furthermore, the method for manufacturing a wiring board according to the present invention is characterized in that a surface of the metal foil to be bonded to the mother substrate is a roughened surface.

  According to the method for manufacturing a wiring board of the present invention, a plurality of wiring board bodies are formed on the lower surface of the mother board in which a plurality of wiring board bodies are integrally formed vertically and horizontally with a cutting region at the boundary between them. And joining a metal foil to be a metal heat sink so as to cover the cutting region, then etching away the region corresponding to the cutting region in the metal foil, and then cutting the mother substrate in the cutting region A thin wiring board that can efficiently join the wiring board body and the metal heat sink, is free from burrs and stretches, and has a thin metal heat sink. A method of manufacturing a wiring board that can be manufactured can be provided.

  Furthermore, when the surface of the metal foil to be bonded to the mother substrate is a roughened surface, there is an advantage that the metal heat sink and the semiconductor element can be firmly adhered.

  Next, the manufacturing method of the wiring board of this invention is demonstrated in detail based on Fig.1 (a)-(d). These drawings are schematic cross-sectional views for each process for explaining the method for manufacturing a wiring board of the present invention, and the wiring board shown in FIG. 2 is manufactured through these processes. In the figure, reference numeral 1a denotes an insulating plate and 1b denotes an insulating layer, which form the insulating substrate 1. Further, 2a is an inner wiring conductor layer, and 2b is a surface wiring conductor layer, and a part of the wiring conductor 2 is formed by these. 3 is a wiring board body, 4 is an adhesive layer, 4P is an adhesive sheet for the adhesive layer 4, 5 is a metal heat sink, 5P is a copper foil for the metal heat sink 5, 6 is a through hole, and 7 is a hole filling Resin, 8 is a resist layer, A is a cutting region, and C is a through hole for accommodating a semiconductor element.

  First, as shown in FIG. 1 (a), an uncured adhesive and a mother board 10 in which a plurality of wiring board main bodies 3 are integrally arranged vertically and horizontally with a cutting region A interposed therebetween. An adhesive sheet 4P for the layer 4 and a copper foil 5P for the heat radiating metal plate 5 are prepared.

  The mother substrate 10 has a thickness of 7 to 35 μm on both surfaces of an insulating plate 1a having a thickness of 0.06 to 1.40 mm, for example, a glass cloth base material impregnated with a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin. An inner wiring conductor layer 2a made of copper foil, an insulating layer 1b having a thickness of 0.02 to 0.15 mm obtained by impregnating a glass cloth base material with a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin, and a thickness A surface layer wiring conductor layer 2b composed of a copper foil having a thickness of 3 to 35 μm and a copper plating having a thickness of 10 to 70 μm is sequentially laminated, and is a large laminated substrate having a length and width of about 500 to 600 mm. Through holes C and through holes 6 are received, and the inner walls of the through holes C and the inner walls of the through holes 6 have predetermined upper and lower wiring conductors 2 each other. Conductor layer thickness for electrical connection is made of copper plating of 10~70μm is adhered. Further, a hole-filling resin 7 made of a thermosetting resin such as an epoxy resin that covers a part of the wiring conductor 2 on the upper surface and fills the inside of the through hole 6 is attached to the upper surface of each wiring board body 3. A resist layer 8 made of a thermosetting resin such as an epoxy resin that covers the wiring conductor 2 on the lower surface is attached to the lower surface of each wiring board body 3.

  Such a mother substrate 10 has an inner-layer wiring conductor on both surfaces of an insulating plate 1a having a thickness of 0.06 to 1.40 mm in which a glass cloth base material is impregnated with a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin. The copper foil in the double-sided copper-clad board to which a copper foil having a thickness of 7 to 35 μm for the layer 2a is adhered is etched into a predetermined pattern corresponding to the inner wiring conductor layer 2a, and then the inner wiring conductor layer 2a is A thickness of 0.02 to 0.15 mm for an insulating layer 1b in which a glass cloth base material is impregnated with a thermosetting resin component such as an epoxy resin or a bismaleimide triazine resin on both sides of the formed double-sided copper-clad plate Laminated insulating sheets (prepregs) and copper foils having a thickness of 3 to 35 μm for the surface wiring conductor layer 2b are laminated and heated while being pressed by a press device to insulate the insulating layer 1b. The sheet is thermally cured to form a laminated body for the mother substrate 10, and then through holes C and through holes 6 are drilled in the laminated body using a cutting device such as a router or a drill machine, and then the through holes C are formed. Electroless copper plating and electrolytic copper plating are applied to the inner wall of the through hole 6 and the inner wall of the through hole 6 and the surface of the copper foil for the surface wiring conductor layer 2b, and the surface wiring conductor layer 2b and the through hole conductor are formed by a so-called solder peeling method. It is formed by depositing hole filling resin 7 and resist layer 8. The hole-filling resin 7 fills the through-hole 6 with a resin paste containing a thermosetting resin component having photosensitivity such as an acrylic-modified epoxy resin on the insulating layer 1b and the surface wiring conductor layer 2b on the upper surface side. In this way, it is formed by applying and exposing to a predetermined pattern and developing. The resist layer 8 is also applied to a resin paste containing a thermosetting resin component having photosensitivity, such as an acrylic-modified epoxy resin, on the insulating layer 1b and the surface wiring conductor layer 2b on the lower surface side. This pattern is formed by exposure and development.

  The adhesive sheet 4P is obtained by molding an uncured composition of a thermosetting resin such as an epoxy resin into a sheet having a thickness of about 60 to 150 μm and drying or semi-curing it, and is commercially available as an adhesive sheet. Can be used. Note that the adhesive sheet 4P is punched by punching a portion corresponding to the through hole C in the mother board 10.

  Further, the copper foil 5P is made of an electrolytic copper foil or a rolled copper foil having a thickness of about 75 to 300 μm, and one main surface thereof is roughened to an arithmetic average roughness Ra of Ra = 0.3 to 1.8 μm. It is preferable that the surface is covered with nickel plating having a thickness of 1 to 20 μm. Further, no slit or the like is formed in the portion corresponding to the cutting area A of the mother substrate 10, and therefore, distortion and deformation are hardly caused even though the thickness is as thin as about 75 to 300 μm.

  Next, as shown in FIG.1 (b), the copper foil 5P is joined to the lower surface of the motherboard 10 via the adhesive sheet 4P. In order to bond the copper foil 5P to the lower surface of the mother substrate 10 via the adhesive sheet 4P, the uncured or semi-cured adhesive sheet 4P and the copper foil 5P are stacked on the lower surface of the mother substrate 10, and these are pressed. A method is employed in which the adhesive sheet 4P is thermally cured by heating while being pressurized. At this time, the copper foil 5P for the metal heat radiating plate 5 is joined to a large number of wiring board bodies 3 at the same time, so that the operation becomes extremely simple. Therefore, a large number of wiring boards can be manufactured extremely efficiently. In addition, the copper foil 5P is not processed with slits or the like, and is less likely to be distorted or deformed when bonded to the mother board 10. Therefore, although it is as thin as 75 to 300 μm, it can be satisfactorily bonded to the mother board 10, and as a result, a thin wiring board can be provided. The copper foil 5P and the mother board 10 can be firmly bonded via the adhesive sheet 4P by bonding the roughened surface of the copper foil 5P to the mother board 10 side, and the copper foil 5P. It is possible to bond the metal heat sink 5 and the semiconductor element S, which are formed from the above, extremely firmly. Therefore, it is preferable to bond the roughened surface of the copper foil 5P with the mother substrate 10 side.

  Next, as shown in FIG. 1 (c), the part corresponding to the cutting area A of the copper foil 5P is removed by etching with a width slightly wider than the cutting area A, and each of them is independent on the lower surface of each wiring board body 3. A metal heat sink 5 is formed. In order to etch away the portion corresponding to the cut region A of the copper foil 5P, the entire upper surface of the mother substrate 10 is protected with an etching resist, and the portion corresponding to the cut region A of the mother substrate 10 is exposed on the lower surface of the copper foil 5P. The copper foil 5P exposed from the etching resist may be etched with a commercially available copper etching solution containing ferric chloride or cupric chloride. The etching resist is stripped and removed using a commercially available resist stripping solution containing sodium hydroxide after etching the copper foil 5a.

  Next, as shown in FIG. 1 (d), a large number of wiring boards in which the mother board 10 is cut in the cutting area A and the individual metal heat sinks 5 are joined to the lower surface of the individual wiring board main body 3. Produced simultaneously and intensively. At this time, since the copper foil 5P at the portion corresponding to the cutting area A of the mother board 10 is removed by etching, even if the mother board 10 is cut in the cutting area A, the metal heat radiating plate 5 is burred or extended. There is nothing at all. Therefore, according to the method for manufacturing a wiring board of the present invention, it is possible to efficiently join the wiring board body and the metal heat sink, and the metal heat sink does not generate burrs or stretches, and has a thickness. It is possible to manufacture a thin wiring board provided with a thin metal heat sink.

(A)-(d) is a schematic sectional drawing for every process for demonstrating the manufacturing method of the wiring board of this invention. It is a schematic sectional drawing of the wiring board manufactured by the manufacturing method of the past and this invention. (A)-(c) is a schematic sectional drawing for every process for demonstrating the manufacturing method of the conventional wiring board. (A) And (b) is a schematic sectional drawing for every process for demonstrating another manufacturing method of the conventional wiring board.

Explanation of symbols

1: Insulating substrate 1a: Insulating plate 1b for forming insulating substrate 1: Insulating layer 2 for forming insulating substrate 1: Wiring conductor 2a: Inner layer wiring conductor layer 2b for forming wiring conductor 2: Wiring conductor 2 Surface wiring conductor layer 3 to be formed: Wiring board body 4: Adhesive layer 4P: Adhesive sheet 5 for forming the adhesive layer 4: Metal heat sink 5P: Copper foil 10 for forming the metal heat sink 5: Mother board A: Cutting region C: Through hole S for accommodating semiconductor element S: Semiconductor element

Claims (2)

  A wiring board body in which a wiring conductor to which an electrode of the semiconductor element is electrically connected is disposed on an upper surface of an insulating substrate having a through hole for accommodating a semiconductor element in the center, and a lower surface of the wiring board body A method of manufacturing a wiring board, which is joined so as to close the through-hole, and has a metal heat dissipating plate on which the semiconductor element is mounted on an upper surface exposed in the through-hole. Forming a plurality of wiring board main bodies in a matrix including a plurality of wiring board bodies in a vertical and horizontal arrangement with a cutting region at the boundary of the wiring board main bodies, and a lower surface of the mother board. Bonding a metal foil serving as the metal heat sink so as to cover the plurality of wiring board main bodies and the cutting region, etching and removing a region corresponding to the cutting region in the metal foil, and the mother Board Method for manufacturing a wiring board, which comprises a step of cutting the serial cutting region.   2. The method for manufacturing a wiring board according to claim 1, wherein a surface of the metal foil to be bonded to the mother substrate is a roughened surface.

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