JP2015128120A - Multi-piece wiring board and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-piece wiring board which is unlikely to cause chips and cracks in wiring board at the time of dicing; and provide a multi-piece wiring board which can form a wiring board having another shape other than a rounded rectangle and a rectangle after being divided by dicing.SOLUTION: A wiring board 10 comprises: an etchable support substrate 1 in which a frame part 4 having an opening 4a to partition a tabular bottom plate 3 into a number of product formation regions X arranged in a matrix is installed on the bottom plate 3 in a protruding manner; an insulation layer 5 which is formed on a top face of the support substrate 1 to fill up the opening 4a and has a thickness to thinly cover a top face of the frame part 4; and a wiring conductor 6 which is formed on the insulation layer 5 on the produce formation regions X to form a wiring board 2 together with the insulation layer 5 on the product formation region X.

Description

  The present invention relates to a multi-piece wiring board formed by arranging a large number of small wiring boards vertically and horizontally and a method for manufacturing the same.

  Conventionally, as a multi-cavity wiring board for CSP (chip size package), a large number of small wiring boards formed by laminating an insulating layer and a conductor layer are integrally formed vertically and horizontally on a support substrate made of metal. A multi-cavity wiring board is known.

  In such a multi-cavity wiring board, a semiconductor element is mounted on each small wiring board formed integrally on a support substrate, and a sealing resin layer is provided so as to cover the semiconductor element on substantially the entire upper surface. After forming and then etching away the support substrate, the semiconductor element mounted on the wiring substrate is sealed with a sealing resin by cutting and dividing along the boundary of each small wiring substrate by dicing A large number of small semiconductor devices are manufactured simultaneously.

  However, in the conventional multi-cavity wiring board described above, since the resin layer forming the wiring board is thin and the mechanical strength is low, if the dicing is performed after the support substrate is removed by etching, the wiring is caused by the stress applied during the dicing. The substrate is easily cracked or chipped. In addition, since the multi-piece wiring board and the sealing resin thereon are diced to be divided into small semiconductor devices, the shape of the divided wiring board is limited to a rectangular shape with corners. Therefore, when a wiring board having a square shape with rounded corners or a shape other than a square is required according to the design of the casing of an electronic device in which a semiconductor device having a semiconductor element mounted on the wiring board is accommodated, this requirement is met. It is difficult to respond.

JP 2004-111641 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-piece wiring board that is less likely to be cracked or chipped when dicing. Furthermore, an object of the present invention is to provide a multi-piece wiring board capable of forming a wiring board having a quadrangular shape with rounded corners or a shape other than a quadrangular shape after being divided by dicing.

  The multi-cavity wiring board according to the present invention includes an etching support substrate formed by projecting a frame portion having openings on a flat bottom plate to divide the bottom plate into a large number of product formation regions arranged vertically and horizontally. An insulating layer formed on an upper surface of the support substrate, filling the opening and covering the upper surface of the frame portion thinly; and an insulating layer on the product forming region; And a wiring conductor that forms a wiring board together with the insulating layer on the formation region.

  The method of manufacturing a multi-cavity wiring board according to the present invention includes an etching process in which a frame portion having openings that divide the bottom plate into a large number of vertical and horizontal product forming regions is provided on a flat bottom plate. A first step of preparing a possible support substrate, a second step of forming an insulating layer having a thickness that fills the opening and thinly covers the frame portion on the support substrate, and each product formation And a third step of forming a wiring conductor on the insulating layer on the region.

  According to the multi-cavity wiring board of the present invention, the insulating layer having a thickness that fills the inside of the opening of the frame portion and thinly covers the upper surface of the frame portion is formed on the upper surface of the support substrate. Since the wiring conductor is formed on the upper surface, the semiconductor element is mounted on each wiring board and the sealing resin layer covering the semiconductor element is formed on the substantially entire upper surface, and then the supporting substrate is removed by etching. The boundary of the wiring board is formed by a step from which the frame portion is removed, and a thin insulating layer remains. Therefore, when cutting and dividing along the boundary of each wiring substrate by cutting, it is only necessary to cut the sealing resin layer and the thin insulating layer, thereby effectively preventing the wiring substrate from being cracked or chipped. be able to.

  Furthermore, according to the multi-cavity wiring board of the present invention, the shape of the inner periphery of the opening portion of the frame portion is, for example, a square shape with rounded corners or a shape other than a square shape, By forming a wiring board having an outer shape corresponding to the shape of the circumference, a semiconductor element is mounted on each wiring board, and a sealing resin layer covering the semiconductor element is formed on substantially the entire upper surface, and then the support substrate is etched. After removing, by cutting the sealing resin layer and the thin insulating layer by dicing along the boundary of each wiring board, the sealing resin is a square with a corner, but most of the thickness of the wiring board is The shape may be a quadrangular shape with rounded corners or a shape other than a quadrangular shape.

  Further, according to the method for manufacturing a multi-cavity wiring board of the present invention, an etchable support substrate having a projecting frame portion having openings for partitioning a flat bottom plate into a large number of product formation regions arranged in rows and columns. An insulating layer having a thickness that fills the inside of the opening and thinly covers the frame portion is formed on the upper portion, and then a wiring conductor is formed on the insulating layer on each product formation region. It is possible to provide a multi-cavity wiring board that is less likely to be cracked or chipped. Furthermore, if the shape of the inner periphery of the opening that divides the bottom plate into product formation areas is set to, for example, a square shape with rounded corners or a shape other than a quadrangle, after being divided by dicing, other shapes other than the square with a rounded corner or the quadrangle are formed. A multi-piece wiring board capable of forming a wiring board having the wiring board can be provided.

1A and 1B are a schematic cross-sectional view showing an example of an embodiment of a multi-cavity wiring board according to the present invention and an exploded perspective view seen from the upper surface side. 2A and 2B are a schematic cross-sectional view showing a state in which a semiconductor element is mounted on the multi-piece wiring board shown in FIGS. 1A and 1B and a perspective view seen from the upper surface side. 3A and 3B are schematic cross-sectional views showing a state in which a sealing resin layer is formed on a multi-piece wiring board on which the semiconductor elements shown in FIGS. 2A and 2B are mounted. It is the perspective view seen from the upper surface side. 4A and 4B are a schematic cross-sectional view and a top view showing a state in which solder bumps are formed on the multi-piece wiring board on which the sealing resin layer shown in FIGS. 3A and 3B is formed. It is the perspective view seen from the side. 5A and 5B are a schematic cross-sectional view showing a state where the support substrate in the multi-piece wiring substrate shown in FIGS. 4A and 4B is removed by etching and a perspective view seen from the lower surface side. is there. 6 (a) and 6 (b) are schematic cross-sectional views showing a state in which the multi-piece wiring board from which the supporting board shown in FIGS. 5 (a) and 5 (b) has been removed is divided by dicing, and viewed from the lower surface side. FIG. FIGS. 7A and 7B are a schematic cross-sectional view and a top view showing a state in which the multi-piece wiring board with the supporting substrate shown in FIGS. 4A and 4B is divided together with the sealing resin layer by dicing. It is the perspective view seen from the side. FIGS. 8A and 8B are a schematic cross-sectional view and a perspective view seen from the upper surface side for explaining the method for manufacturing a multi-piece wiring board of the present invention. 9A and 9B are a schematic cross-sectional view and a perspective view seen from the upper surface side for explaining the method for manufacturing a multi-piece wiring board of the present invention. 10A and 10B are a schematic cross-sectional view and a perspective view seen from the upper surface side for explaining the method for manufacturing a multi-piece wiring board according to the present invention. 11A and 11B are a schematic cross-sectional view and a perspective view seen from the upper surface side for explaining the method for manufacturing a multi-piece wiring board of the present invention.

  Next, an example of an embodiment of the multi-piece wiring board of the present invention will be described with reference to the accompanying drawings. As shown in FIGS. 1A and 1B, the multi-piece wiring substrate 10 of this example includes a support substrate 1 and a wiring substrate 2 formed on the support substrate 1.

  The support substrate 1 includes a flat bottom plate 3 and a frame portion 4 projecting from the bottom plate 3. The bottom plate 3 has a plurality of product forming regions X on its upper surface, and a frame portion 4 is projected so as to have an opening 4 a that partitions the upper surface of the bottom plate 3 into the product forming regions X. In this example, the inner periphery of the opening 4a has a quadrangular shape with rounded corners. The support substrate 1 is formed by projecting a frame portion 4 by etching the upper surface of a copper foil having a thickness of about 120 to 240 μm and etching the portion of the product formation region X, and the thickness of the bottom plate 3 is 100 to 100 mm. The thickness of the frame portion 4 is about 10 to 30 μm. In this example, the case where four product forming regions X are provided is shown for the sake of brevity, but a larger number of product forming regions X are actually arranged.

  The wiring substrate 2 is formed on the product formation region X of the support substrate 1 so as to be in close contact with the bottom plate 3 and the inner peripheral surface of the frame portion 4. The wiring board 2 includes an insulating layer 5 formed on the bottom plate 3 in the product formation region X, a wiring conductor 6 formed thereon, and a solder resist layer 7 formed thereon. A part of the insulating layer 5 covers the upper surface of the frame 4 thinly with a thickness of about 1 to 5 μm.

  The insulating layer 5 is made of an electrically insulating material in which an inorganic insulating filler such as silica is dispersed in a thermosetting resin such as an epoxy resin or a polyimide resin. The thickness of the insulating layer 5 is, for example, about 10 to 30 μm. The wiring conductor 6 is made of, for example, a copper plating layer. The thickness of the wiring conductor 6 is, for example, about 5 to 15 μm.

  The wiring conductor 6 has a semiconductor element connection pad 8 and an external connection pad 9 in a part thereof. These semiconductor element connection pads 8 and external connection pads 9 are exposed to the outside through openings provided in the solder resist layer 7.

  The solder resist layer 7 is made of a photosensitive thermosetting resin such as an acrylic-modified epoxy resin. The thickness of the solder resist layer 7 is about 5 to 15 μm on the wiring conductor 6.

  Here, a manufacturing method of a semiconductor device in which a semiconductor element is mounted on each wiring board 2 and resin-sealed using the multi-cavity wiring board 10 of this example will be described.

  First, as shown in FIGS. 2A and 2B, the semiconductor element S is mounted on each wiring board 2 of the multi-piece wiring board 10. The semiconductor element S is mounted by flip-chip connecting the electrode terminals T of the semiconductor element S to the semiconductor element connection pads 8 of the wiring board 2 via solder.

  Next, as shown in FIGS. 3A and 3B, an opening Ma that covers the semiconductor element S and exposes the external connection pad 9 on the upper surface of the multi-piece wiring substrate 10 on which the semiconductor element S is mounted is formed. An encapsulating resin layer M is formed by a transfer molding method.

  Next, as shown in FIGS. 4A and 4B, solder bumps B are formed on the external connection pads 9 exposed in the openings Ma. The solder bump B is formed by applying a flux in the opening Ma, and then placing a solder ball thereon to perform a reflow process.

  Next, as shown in FIGS. 5A and 5B, the support substrate 1 is removed by etching. Since the support substrate 1 is made of copper, it can be easily etched with an etchant containing, for example, ferric chloride or cupric chloride. At this time, the boundary of each wiring board 2 is formed by a step of the trace from which the frame portion 4 is removed. Only the thin insulating layer 5 and the sealing resin layer M exist in the stepped portion.

  Next, as shown in FIGS. 6A and 6B, the semiconductor element S mounted on the wiring board 2 is resin-sealed by the sealing resin layer M by dicing along the boundary of each wiring board 2. The formed semiconductor device is formed. At this time, since only the thin insulating layer 5 and the sealing resin layer M located at the boundary of the wiring board 2 have to be cut, the wiring board 2 is not cracked or chipped due to dicing stress.

  Further, according to the multi-piece wiring board 10 of the present invention, the inner periphery of the opening 4a of the support substrate 1 has a square shape with rounded corners, and the wiring board 2 is located on the product formation region X of the support substrate 1. Are formed so as to be in close contact with the inner surface of the bottom plate 3 and the opening 4a. Therefore, as described above, the semiconductor element S is mounted on each wiring board 2, and the semiconductor element S is formed on substantially the entire upper surface. In the semiconductor device to be obtained, the sealing resin layer M is formed by cutting the support substrate 1 by etching and then cutting the support substrate 1 by dicing along the boundaries of the wiring substrates 2. Is a quadrangular shape with corners, but the wiring board 2 itself can be a quadrangular shape with rounded corners. Furthermore, the shape of the opening 4a of the frame portion 4 is a shape other than a quadrangle, and the wiring substrate 2 is formed so as to be in close contact with the inner peripheral surface of the opening 4a, thereby obtaining the wiring substrate 2 having a shape other than the quadrangle. Can do.

  In the above-described example, the support substrate 1 of the multi-piece wiring substrate 10 is diced after being removed by etching. However, as shown in FIGS. 7A and 7B, the support substrate 1 of the wiring substrate 10 is left attached. After dicing, the support substrate 1 may be removed by etching from the divided wiring substrate 2.

  Next, a method for manufacturing the multi-piece wiring board 10 described above will be described. First, as shown in FIGS. 8A and 8B, a support substrate 1 is prepared. As described above, the support substrate 1 is formed by protruding the frame portion 4 having a thickness of about 10 to 30 μm on the upper surface of the bottom plate 3 having a thickness of about 100 to 200 μm. An opening 4 a that partitions the upper surface of the bottom plate 3 into a plurality of product formation regions X is formed in the frame portion 4. Such a support substrate 1 is formed by etching the upper surface of a copper foil having a thickness of about 120 to 240 μm.

  Next, as shown in FIG. 9, the insulating layer 5 is formed so as to fill the inside of the opening 4 a on the upper surface of the bottom plate 3 and cover the frame 4 with a thin thickness of about 1 to 5 μm. As described above, the insulating layer 5 is made of an electrically insulating material in which an inorganic insulating filler such as silica is dispersed in a thermosetting resin such as an epoxy resin or a polyimide resin, and has a thickness of about 10 to 30 μm. The insulating layer 5 is formed, for example, by sticking an uncured film of an electrically insulating material to the upper surface of the support substrate 1 by hot pressing and then thermosetting.

  Next, as shown in FIG. 10, the wiring conductor 6 is formed on the upper surface of the insulating layer 5 on each product formation region X. The wiring conductor 6 is made of a copper plating layer having a thickness of about 5 to 15 μm and is formed by a known semi-additive method.

  Finally, as shown in FIG. 11, a solder resist layer having openings for exposing a part of the wiring conductor 6 as the semiconductor element connection pad 8 and the external connection pad 9 on the upper surface of the insulating layer 5 on which the wiring conductor 6 is formed. 7 is formed. The solder resist layer 7 is made of a photosensitive thermosetting resin such as an acrylic-modified epoxy resin, and the thickness on the wiring conductor 6 is about 5 to 15 μm. The solder resist layer 7 is formed by applying a photosensitive thermosetting resin paste to the upper surface of the insulating layer 5 on which the wiring conductor 6 is formed so as to completely cover the wiring conductor 6 and drying it, and then performing well-known photo processing. The semiconductor device connection pad 8 and the external connection pad 9 are exposed and developed so as to have an opening for exposing the semiconductor element connection pad 8 and the external connection pad 9, and then thermally cured.

  Thus, according to the manufacturing method of the multi-cavity wiring board 10 of the present invention, the frame portion 4 having the openings 4a that divide the bottom plate 3 into a large number of product formation regions X arranged vertically and horizontally on the flat bottom plate 3. Is prepared, and an insulating layer 5 is formed on the support substrate 1 so as to fill the opening 4a and cover the frame 4 thinly. By forming the wiring conductor 6 on the insulating layer 5 on each product forming region X, it is possible to provide a multi-piece wiring substrate 10 in which the wiring substrate 2 is not easily cracked or chipped when dicing. Furthermore, if the shape of the inner periphery of the opening 4a that divides the bottom plate 3 into the product formation region X is set to a square shape with a rounded corner or a shape other than a square, for example, after being divided by dicing, A multi-piece wiring board 10 capable of forming wiring boards 2 having other shapes can be provided.

  Note that the present invention is not limited to the above-described embodiment, and various modifications are possible as long as they do not depart from the gist of the present invention. For example, in the above-described embodiment, the wiring conductor 6 has Although formed by the semi-additive method, it may be formed by a well-known subtractive method. In this case, a copper foil can be used as the wiring conductor 6. In the above-described embodiment, the wiring board 2 is formed with one insulating layer 5 and one wiring conductor 6 each. However, the wiring board 2 may be formed with a multilayer structure in which a plurality of insulating layers 5 and wiring conductors 6 are stacked. good.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Wiring board 3 Bottom plate 4 Frame part 4a Opening part 5 Insulating layer 6 Wiring conductor 7 Solder resist layer X Product formation area

Claims (4)

  An etchable support substrate is formed on a flat bottom plate by projecting a frame portion having openings for partitioning the bottom plate into a large number of product formation regions arranged vertically and horizontally, and formed on the upper surface of the support substrate. And an insulating layer having a thickness that fills the opening and thinly covers the upper surface of the frame portion, and the insulating layer on the product forming region, and together with the insulating layer on the product forming region, a wiring board And a wiring conductor for forming a multi-piece wiring board.   2. The multi-cavity wiring board according to claim 1, wherein the inner periphery of the opening has a quadrangular shape with rounded corners or a shape different from the quadrangular shape.   A first step of preparing an etchable support substrate in which a frame having an opening for partitioning a plurality of product forming regions arranged vertically and horizontally on the bottom plate is provided on a flat bottom plate; A second step of forming an insulating layer having a thickness that fills the inside of the opening and covers the frame portion thinly on the substrate; and a third step of forming a wiring conductor on the insulating layer on each product formation region And a process for producing a multi-piece wiring board.   4. The method for manufacturing a multi-piece wiring board according to claim 3, wherein an inner periphery of the opening is a quadrangular shape with rounded corners or a shape different from the quadrangular shape.

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