JP2016219705A - Wiring board and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board in which a semiconductor element connection pad of the top layer is less likely to be peeled, and which has a high electric insulation reliability between the semiconductor element connection pads, and an excellent electric connection between the semiconductor element connection pad and an electrode terminal of a semiconductor element.SOLUTION: A wiring board 10 comprises: an insulation base 1 formed so as to laminate a plurality of insulation resin layers 1a to 1d; a semiconductor element connection pad 4 which is embedded so that an upper surface is exposed to the insulation resin layer 1a, and is connected to an electrode terminal T of a semiconductor device S; an external connection pad 5 which is deposed in a lower surface of the insulation base 1, and electrically connected to the semiconductor element connection pad 4 through a wiring conductor 2 provided in an inner part of the insulation base 1. The semiconductor element connection pad 4 includes a base part 4a of which an upper surface external peripheral part is concavely exposed from the upper surface of the insulation resin layer 1a of the top surface, and a projection part 4b projecting from the upper surface of the insulation resin layer 1a to an upper surface central part of the base part 4a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wiring board used for mounting a semiconductor element and a manufacturing method thereof.

  FIG. 4 shows an example of a conventional wiring board 20 on which the semiconductor element S is mounted. A conventional wiring board 20 includes an insulating base 11 and a wiring conductor 12. The insulating base 11 is formed by laminating a plurality of insulating resin layers 11a to 11d. A via hole 13 is formed in each of the insulating resin layers 11a to 11b. The wiring conductor 12 is formed in the surface of the insulating resin layers 11 a to 11 d and the via hole 13. Thereby, the upper and lower wiring conductors 12 are electrically connected via the via hole 13. A large number of semiconductor element connection pads 14 are formed on the upper surface of the insulating substrate 11. A large number of external connection pads 15 are formed on the lower surface of the insulating substrate 11. The semiconductor element connection pad 14 and the external connection pad 15 are electrically connected to each other through the wiring conductor 12. The wiring conductor 12, the semiconductor element connection pad 14, and the external connection pad 15 are formed of a plated conductor layer. The electrode terminal T of the semiconductor element S is connected to the semiconductor element connection pad 14. The external connection pad 15 is connected to the wiring conductor of the external electric circuit board.

  The wiring board 20 is manufactured as follows. First, as shown in FIG. 5A, a metal foil 32 is supported on a flat support substrate 31. The support substrate 31 and the metal foil 32 are laminated with an intervening layer 33 interposed therebetween. The support substrate 31 and the intervening layer 33 are fixed to each other. The metal foil 32 and the intervening layer 33 are in close contact with each other through an adhesive layer (not shown) so as to be peeled off. The support substrate 31 and the metal foil 32 are fixed. The support substrate 31 is made of a thermosetting resin containing glass cloth. The metal foil 32 is made of copper foil. The intervening layer 33 is made of a copper foil or a resin film.

  Next, as shown in FIG. 5B, the plated conductor layer 14 a is formed on the metal foil 32. The plated conductor layer 14 a is to be the semiconductor element connection pad 14. The plated conductor layer 14a is made of electrolytic copper plating.

  Next, as shown in FIG. 5C, the first insulating resin layer 11a and the wiring conductor 12 are formed on the metal foil 32 and the plated conductor layer 14a. A via hole 13 for connecting to the plated conductor layer 14a is formed in the insulating resin layer 11a. The plated conductor layer 14 a and the wiring conductor 12 are electrically connected to each other through the via hole 13.

  Next, as shown in FIG. 5D, the next insulating resin layer 11b and the wiring conductor 12 are formed on the insulating resin layer 11a and the wiring conductor 12 thereon, and the next insulating resin layer 11c is further formed. Then, the wiring conductor 12 is formed. Via holes 13 are also formed in the insulating resin layers 11b and 11c. The upper and lower wiring conductors 12 are electrically connected to each other through the via hole 13.

  Next, as shown in FIG. 5E, the final insulating resin layer 11d is laminated, and the external connection pads 15 are formed on the insulating resin layer 11d. The external connection pad 15 is composed of a part of the wiring conductor 12. A via hole 13 is also formed in the insulating resin layer 11d. The external connection pad 15 is electrically connected to the underlying wiring conductor 12 through the via hole 13. As a result, the external connection pad 15 is electrically connected to the plating conductor layer 14 a via the wiring conductor 12.

  Next, as shown in FIG. 6F, a portion corresponding to the region where the metal foil 32 and the support substrate 31 are fixed is cut off. Thereby, only the part corresponding to the area | region where metal foil 32 and interposition layer 33 were stuck so that peeling was possible remains.

  Next, as shown in FIG. 6G, the metal foil 32 and the support substrate 31 are separated by peeling the metal foil 32 and the intervening layer 33. Thereby, the metal foil 32 is exposed to the outside.

  Finally, as shown in FIG. 6H, the exposed metal foil 32 is removed by etching. Thereby, the plating conductor layer 14a embedded in the insulating resin layer 11a is exposed to the outside. The exposed plated conductor layer 14 a becomes the semiconductor element connection pad 14. At this time, the plating conductor layer 14a is also etched by about 2 to 3 μm. Therefore, the exposed surface of the semiconductor element connection pad 14 is recessed by about 2 to 3 μm from the surface of the insulating resin layer 11a.

  However, in the conventional wiring board 20, as described above, the semiconductor element connection pad 14 is recessed by about 2 to 3 μm from the surface of the insulating resin layer 11a. Therefore, an electrical connection failure is likely to occur between the semiconductor element connection pad 14 and the electrode terminal T of the semiconductor element S. This is because good contact between the semiconductor element connection pad 14 recessed from the surface of the insulating resin layer 11a and the electrode terminal T of the semiconductor element S is hindered by the recess.

  In addition, there is a wiring board in which the semiconductor element connection pads are not embedded in the insulating resin layer, but are simply projected on the surface of the insulating resin layer. In this case, the semiconductor element connection pads are insulated particularly when the semiconductor element connection pads are small. It becomes easy to peel from the resin layer. Moreover, when the distance between adjacent semiconductor element connection pads is small, the electrical insulation reliability is low.

JP 2007-300167 A

  The problem to be solved by the present invention is that the semiconductor element connection pad is difficult to peel off from the uppermost insulating resin layer, and the electrical insulation reliability between adjacent semiconductor element connection pads is high, and the semiconductor element connection pad and the semiconductor An object of the present invention is to provide a wiring board having good electrical connection with electrode terminals of an element and a method for manufacturing the same.

  The wiring board of the present invention is embedded with an insulating base formed by laminating a plurality of insulating resin layers on the top and bottom, and the uppermost insulating resin layer so that the upper surface is exposed, and is connected to an electrode terminal of a semiconductor element. A semiconductor element connection pad, and an external connection pad that is attached to the lower surface of the insulating base and is electrically connected to the semiconductor element connection pad via a wiring conductor provided inside the insulating base; The semiconductor element connection pad has a base part whose upper surface outer peripheral part is recessed and exposed from the upper surface of the uppermost insulating resin layer, and is located at the uppermost center part of the base part. It has a projection part which protrudes from the upper surface of the insulating resin layer of the upper layer.

  The method for manufacturing a wiring board according to the present invention includes a step of supporting a metal foil on a flat support substrate in a separable manner, and forming a plating conductor layer having a large number of patterns serving as a base of a semiconductor element connection pad on the metal foil. And laminating a first insulating resin layer which is an uppermost insulating resin layer on the metal foil and the plated conductor layer, and electrically connecting the plated conductor layer to the first insulated resin layer. Forming a wiring conductor connected to each other, and laminating an insulating resin layer of the next layer on the first insulating resin layer and the wiring conductor, and forming the wiring on the insulating resin layer of the next layer A step of forming a wiring conductor of the next layer electrically connected to the conductor, and further lamination of the insulating resin layer of the next layer and wiring of the next layer on the insulating resin layer of the next layer and the wiring conductor of the next layer The process of repeating conductor formation multiple times as necessary A step of forming an external connection pad electrically connected to the plating conductor via the wiring conductor on the insulating resin layer laminated last, and separating the metal foil and the support substrate. The step of exposing the metal foil, the metal foil and the plated conductor layer are partially etched, and protrude from the surface of the first insulating resin layer to the center of the surface of the base formed of each pattern of the plated conductor layer And a step of leaving a part of the metal foil as a protruding portion and denting the outer peripheral portion of the surface of the base from the surface of the first insulating resin layer.

  According to the wiring board of the present invention, since the base portion of the semiconductor element connection pad is embedded in the uppermost insulating resin layer, it is difficult to peel off from the uppermost insulating resin layer. Further, since the exposed outer peripheral portion of the base portion of the semiconductor element connection pad is recessed from the upper surface of the uppermost insulating resin layer, even if the distance between adjacent semiconductor element connection pads is small, these Thus, the electrical insulation reliability between the semiconductor element connection pads is excellent. In addition, since a protrusion projecting from the upper surface of the uppermost insulating resin layer is provided at the center of the upper surface of the base portion of the semiconductor element connection pad, the electrical connection between the semiconductor element connection pad and the electrode terminal of the semiconductor element is achieved. Connection can be made good.

  Also, according to the method for manufacturing a wiring board of the present invention, after separating the metal foil and the support substrate to expose the metal foil, the plated conductor having a large number of patterns serving as the base of the metal foil and the semiconductor element connection pad The metal layer is partially etched to leave a part of the metal foil as a protrusion protruding from the surface of the first insulating resin layer at the center of the surface of the base composed of each pattern of the plated conductor layer, and the outer periphery of the surface of the base Since the portion is recessed from the surface of the first insulating resin layer, the upper surface is embedded in the uppermost insulating resin layer made of the first insulating resin layer, and the outer peripheral portion of the upper surface is the uppermost insulating layer. A wiring board having a base part that is recessed and exposed from the upper surface of the resin layer and having a protrusion protruding from the upper surface of the uppermost insulating resin layer at the center of the upper surface of the base part is manufactured. be able to. As a result, the semiconductor element connection pads are difficult to peel from the first insulating resin layer, are excellent in electrical insulation reliability between adjacent semiconductor element connection pads, and are electrically connected to the electrode terminals of the semiconductor element connection pads and the semiconductor elements. It is possible to provide a wiring board capable of improving the general connection.

FIG. 1 is a schematic sectional view showing an embodiment of a wiring board according to the present invention. FIG. 2 is a schematic cross-sectional view for each process for explaining an embodiment of the method for manufacturing a wiring board of the present invention. FIG. 3 is a schematic cross-sectional view for each step for explaining an embodiment of the method for manufacturing a wiring board of the present invention. FIG. 4 is a schematic cross-sectional view showing a conventional wiring board. FIG. 5 is a schematic cross-sectional view for each process for explaining a conventional method of manufacturing a wiring board. FIG. 6 is a schematic cross-sectional view for each process for explaining a conventional method of manufacturing a wiring board.

  Next, an embodiment of the wiring board according to the present invention will be described with reference to FIG. As shown in FIG. 1, the wiring board 10 includes an insulating base 1 and a wiring conductor 2. A large number of semiconductor element connection pads 4 are formed on the upper surface of the insulating substrate 1. Further, a large number of external connection pads 5 are formed on the lower surface of the insulating substrate 1.

  The insulating base 1 is formed by laminating a plurality of insulating resin layers 1a to 1d. Each of the insulating resin layers 1a to 1d is made of, for example, an electrically insulating material obtained by impregnating and applying a thermosetting resin to a glass cloth base material. As the thermosetting resin, epoxy resin, bismaleimide triazine resin, polyimide resin or the like is used. The thickness of each insulating resin layer 1a-1d is about 50-200 micrometers, respectively. Via holes 3 are formed in the respective insulating resin layers 1a to 1d. The diameter of the via hole 3 is about 30 to 100 μm.

  The wiring conductor 2 is deposited on the surfaces of the insulating resin layers 1 a to 1 d and the via holes 3. The wiring conductors 2 positioned above and below the insulating resin layers 1 a to 1 d are electrically connected to each other through the via hole 3. The wiring conductor 2 is mainly composed of a copper plating layer. The thickness of the wiring conductor 2 is about 5 to 20 μm.

  A large number of semiconductor element connection pads 4 are arranged in a lattice pattern. The electrode terminal T of the semiconductor element S is connected to the semiconductor element connection pad 4. The semiconductor element connection pad 4 includes a base portion 4a and a protruding portion 4b.

  The base 4a is circular in plan view. The diameter of the base 4a is about 30 to 100 μm. The base 4a is embedded in the insulating resin layer 1a. The buried depth is about 5 to 20 μm. The outer peripheral portion of the upper surface of the base portion 4a is recessed from the upper surface of the insulating resin layer 1a. The depth of the depression is about 2 to 3 μm. The base 4a is made of a plated conductor layer. As the plating conductor layer, an electrolytic copper plating layer is preferably used.

  The protrusion 4b is formed at the center of the upper surface of the base 4a. The protrusion 4b is circular. The diameter of the protrusion 4b is about 20 to 80 μm. The protrusion 4b protrudes from the upper surface of the insulating resin layer 1a. The protruding height is about 3 to 18 μm. The protrusion 4b is made of a metal foil. A copper foil is preferably used as the metal foil.

  Many external connection pads 5 are arranged in a grid pattern. The external connection pad 5 is connected to a wiring conductor of an external electric circuit board. The external connection pad 5 is circular in plan view. The diameter of the external connection pad 5 is about 200 to 800 μm. The external connection pad 5 is formed by a wiring conductor 2 deposited on the lower surface of the lowermost insulating resin layer 1d. The external connection pad 5 is electrically connected to the semiconductor element connection pad 4 through the wiring conductor 2.

  Then, the semiconductor element S is mounted on the wiring substrate 10 by connecting the electrode terminal T of the semiconductor element S to the upper surface of the protrusion 4 b of the semiconductor element connection pad 4. At this time, since the base portion 4a is embedded in the upper surface side of the insulating resin layer 11a, the semiconductor element connection pad 4 is firmly locked to the insulating resin layer 11a and hardly peels off. Further, since the outer peripheral portion of the upper surface of the base portion 4a of the semiconductor element connection pad 4 is recessed from the upper surface of the insulating resin layer 1a, these semiconductors can be used even when the distance between the adjacent semiconductor element connection pads 4 is small. The electrical insulation reliability between the element connection pads 4 is excellent. Furthermore, since the upper surface of the protrusion 4a connected to the electrode terminal T of the semiconductor element S protrudes from the surface of the insulating resin layer 1a, the electrical connection between the semiconductor element connection pad 4 and the electrode terminal T of the semiconductor element S is achieved. Can be made good.

  Next, an embodiment of the method for manufacturing a wiring board according to the present invention will be described with reference to FIGS. 2 and 3 by taking as an example the case of manufacturing the wiring board 10 described above.

  First, as shown in FIG. 2A, a metal foil 22 is supported on a flat support substrate 21. The support substrate 21 and the metal foil 22 are laminated with an intervening layer 23 interposed therebetween. The support substrate 21 and the intervening layer 23 are fixed to each other. The metal foil 22 and the intervening layer 23 are in close contact with each other via an adhesive layer (not shown) so as to be peeled off. The support substrate 21 and the metal foil 22 are fixed to each other. The support substrate 21 is made of a thermosetting resin containing glass cloth. The thickness of the support substrate 21 is about 400 to 800 μm. The metal foil 22 is made of copper foil. The thickness of the metal foil 22 is about 3 to 18 μm. The intervening layer 23 is made of a copper foil or a resin film. The thickness of the intervening layer 23 is about 3 to 18 μm. The thickness shown here is merely an example, and may be a thickness different from the thickness described above.

  Next, as shown in FIG. 2B, a plated conductor layer 24 having a large number of circular patterns to be the base portions 4a of the semiconductor element connection pads 4 is formed on the metal foil 22 in a predetermined pattern. The plated conductor layer 24 becomes the semiconductor element connection pad 4. The plated conductor layer 24 is made of electrolytic copper plating. The thickness of the plating conductor layer 24 is about 5 to 20 μm. Such a plating conductor layer 24 is formed by forming a plating mask having an opening pattern corresponding to the plating conductor layer 24 on the metal foil 22 and then electrolytically plating the metal foil 22 exposed in the opening pattern of the plating mask. After depositing the layer to the desired thickness, it is formed by removing the plating mask.

  Next, as shown in FIG. 2C, the first insulating resin layer 1 a and the wiring conductor 2 are formed on the metal foil 22 and the plated conductor layer 24. A via hole 3 for connecting to the first plated conductor layer 4a is formed in the first insulating resin layer 1a. The plated conductor layer 24 and the wiring conductor 2 are electrically connected to each other through the via hole 3. The first insulating resin layer 1a heats while placing a prepreg obtained by impregnating and drying an uncured thermosetting resin on a glass cloth substrate on the metal foil 22 on which the plated conductor layer 24 is formed. After pressing, it is formed by thermosetting. The via hole 3 is formed by laser processing, blast processing, or the like. The wiring conductor 2 is formed by a known semi-additive method.

  Next, as shown in FIG. 2D, on the first insulating resin layer 1a and the wiring conductor 2 thereon, the next insulating resin layer 1b is laminated and the wiring conductor 2 is further formed. The next insulating resin layer 1c and the wiring conductor 2 are formed. Via holes 3 are also formed in these insulating resin layers 1b and 1c. The upper and lower wiring conductors 2 are electrically connected to each other through the via hole 3. The insulating resin layers 1b and 1c and the wiring conductor 2 thereon are formed in the same manner as the first insulating resin layer 1a and the wiring conductor 2 thereon.

  Next, as shown in FIG. 2E, the final insulating resin layer 1d is laminated, and the wiring conductor 2 including the external connection pads 5 is formed on the insulating resin layer 1d. A via hole 3 is also formed in the insulating resin layer 1d. The external connection pad 5 is electrically connected to the underlying wiring conductor 2 through the via hole 3. As a result, the external connection pad 5 is electrically connected to the first plating conductor layer 4 a via the wiring conductor 2. The insulating resin layer 1d and the wiring conductor 2 thereon are formed in the same manner as the insulating resin layers 1a to 1c and the wiring conductor 2 thereon.

  Next, as shown in FIG. 3F, a portion corresponding to a region where the metal foil 22 and the support substrate 21 are fixed is cut off by cutting. Thereby, only the part corresponding to the area | region where metal foil 22 and the intervening layer 23 contact | adhered so that peeling was possible remains. A dicer or a router is used for cutting.

  Next, as illustrated in FIG. 3G, the metal foil 22 and the support substrate 21 are separated by separating the metal foil 22 and the intervening layer 23. Thereby, the metal foil 22 is exposed to the outside.

  Next, an etching mask M is formed on the surface of the metal foil 22 as shown in FIG. The etching mask M has a mask pattern that covers the metal foil 23 in a region corresponding to the central portion of each pattern of the plated conductor layer 24 to be the base portion 4a of the semiconductor element connection pad 4. Each mask pattern is circular. The diameter of each mask pattern is about 5 to 50 μm smaller than each pattern of the plated conductor layer 24.

  Next, as shown in FIG. 3 (i), the metal foil 23 and the plating conductor layer 24 exposed from the mask M are partially etched to insulate the center portion of the surface of the base portion 4 a made up of each pattern of the plating conductor layer 24. While leaving a part of the metal foil 22 as the protrusion 4b protruding from the surface of the resin layer 1a, the outer peripheral portion of the surface of the base 4a is recessed from the surface of the insulating resin layer 1a.

  Finally, as shown in FIG. 3J, the etching mask M is stripped and removed. As a result, the base 4a is embedded in the uppermost insulating resin layer 1a and the outer peripheral portion of the upper surface is recessed and exposed from the upper surface of the uppermost insulating resin layer 1a. The wiring substrate 10 including the semiconductor element connection pads 4 having the protrusions 4b protruding from the upper surface of the upper insulating resin layer 1a is completed. Note that FIG. 3J shows a state in which the wiring board 10 is completed in an upside down state.

  Thus, according to the manufacturing method of the wiring board of this example, after separating the metal foil 22 and the support substrate 21 to expose the metal foil 22, the metal foil 22 and the base portion 4a of the semiconductor element connection pad 4 The plating conductor layer 24 having a large number of patterns is partially etched, and the metal foil 22 is formed as a protrusion 4b protruding from the surface of the insulating resin layer 1a at the center of the surface of the base portion 4a composed of each pattern of the plating conductor layer 24. Since the outer peripheral portion of the surface of the base 4a is recessed from the surface of the insulating resin layer 1a, the upper surface of the insulating resin layer 1a is buried so that the upper surface is exposed. A semiconductor element connection pad having a base 4a that is recessed and exposed from the upper surface of the upper insulating resin layer 1a, and a protrusion 4b that protrudes from the upper surface of the uppermost insulating resin layer 1a at the center of the upper surface of the base 4a. It is possible to manufacture the wiring substrate 10 provided with a de-4. As a result, the semiconductor element connection pad 4 is difficult to peel off from the uppermost insulating resin layer 1a, and the electrical insulation reliability between the adjacent semiconductor element connection pads 4 is excellent, and the semiconductor element connection pad 4 and the semiconductor element S It is possible to provide the wiring substrate 10 that can make an excellent electrical connection with the electrode terminal T.

DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 1a-1d ... Insulation layer 2 ... Wiring conductor 4 .... Semiconductor element connection pad 4a ... Base part 4b ... Projection Part 5... External connection pad 21... Support substrate 22... Metal foil 23.

Claims (2)

  An insulating base formed by laminating a plurality of insulating resin layers, a semiconductor element connection pad embedded in the uppermost insulating resin layer so that an upper surface is exposed, and connected to an electrode terminal of the semiconductor element; A wiring board comprising: an external connection pad attached to a lower surface of the insulating base and electrically connected to the semiconductor element connection pad via a wiring conductor provided inside the insulating base. In the semiconductor element connection pad, the outer peripheral portion of the upper surface has a base that is recessed and exposed from the upper surface of the uppermost insulating resin layer, and the uppermost insulating resin layer of the uppermost layer is formed in the center of the upper surface of the base. A wiring board having a protrusion protruding from an upper surface.   A step of detachably supporting a metal foil on a flat support substrate, a step of forming a plated conductor layer having a large number of patterns serving as a base of a semiconductor element connection pad on the metal foil, the metal foil, and the A first insulating resin layer serving as the uppermost insulating resin layer is laminated on the plated conductor layer, and a wiring conductor electrically connected to the plated conductor layer is formed on the first insulating resin layer. And a step of laminating a next insulating resin layer on the first insulating resin layer and the wiring conductor, and a next layer electrically connected to the wiring conductor on the insulating resin layer Forming a wiring conductor of the next layer, and further laminating the insulating resin layer of the next layer and forming the wiring conductor of the next layer a plurality of times as necessary on the insulating resin layer of the next layer and the wiring conductor of the next layer. The process of repeating and the insulation tree laminated last A step of forming an external connection pad electrically connected to the plating conductor via the wiring conductor on a layer; a step of separating the metal foil and the support substrate to expose the metal foil; The metal foil and the plated conductor layer are partially etched, and a protrusion projecting from the surface of the first insulating resin layer is formed at the center of the surface of the base made of each pattern of the plated conductor layer. And a step of recessing the outer peripheral portion of the surface of the base from the surface of the first insulating resin layer while leaving a portion.

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