JP2009224581A - Element mounting substrate and method of manufacturing the same, semiconductor module and method of manufacturing the same, electrode structure, and portable device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for reducing formation cost and improving connection reliability of a connecting metal to a protrusion by using a metal layer as a mask when the protrusion is formed on a wiring layer. <P>SOLUTION: An element mounting substrate includes an insulating resin layer 12, a wiring layer 14 provided on one principal surface of the insulating resin layer, the protrusion 16 which is electrically connected to the wiring layer 14 and protruded from a side opposite to the insulating resin layer side of the wiring layer, a metal layer 17 provided on a crowning of the protrusion 16, and a connecting metal 18 covering at least part of the side surface of the protrusion 16 and the metal layer 17. At least part of the metal layer 17 is protruded to the outside from the side surface of the protrusion 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an element mounting substrate and a manufacturing method thereof, a semiconductor module and a manufacturing method thereof, an electrode structure, and a portable device.

  In recent years, with the miniaturization and high functionality of electronic devices, there has been a demand for further miniaturization of semiconductor elements used in electronic devices. With the miniaturization of semiconductor elements, it is essential to narrow the pitch between electrodes for mounting on a printed wiring board. As a surface mounting method of a semiconductor element, a flip chip mounting method is known in which solder bumps are formed on electrodes of a semiconductor element, and solder bumps and electrode pads of a printed wiring board are soldered. In addition, BGA (Ball Grid Array) and CSP (Chip Size Package) structures are known as structures employing the flip chip mounting method.

Under such circumstances, a technique for improving pattern accuracy and forming high-density connection terminals on a substrate has been proposed (see Patent Document 1).
JP-A-8-125346

  However, in the structure shown in Patent Document 1, when a force is applied in the horizontal direction and / or the vertical direction with respect to the connection terminal, the molten solder for connection may come off, and the connection reliability of the connection terminal may be reduced. there were.

  The present invention has been made in view of such a situation, and an object of the present invention is to use a metal layer as a mask when forming a protrusion on a wiring layer, thereby reducing the formation cost and connecting to the protrusion. Is to provide technology for improving the connection reliability of metal.

  One embodiment of the present invention is an electrode structure. The electrode structure includes a wiring layer, a protrusion that is electrically connected to the wiring layer, protrudes from the wiring layer, a metal layer provided on the top of the protrusion, and at least a part of a side surface of the protrusion And a connecting metal covering the metal layer, and at least a part of the metal layer protrudes outward from the side surface of the protrusion.

  According to this aspect, the connection reliability of the connecting metal to the protrusion is improved due to the presence of the metal layer protruding from the side surface of the protrusion.

  Another aspect of the present invention is an element mounting substrate. The element mounting substrate is electrically connected to the insulating resin layer, the wiring layer provided on one main surface of the insulating resin layer, and the wiring layer, and on the opposite side of the insulating resin layer from the wiring layer. The protrusion part which protrudes, and the metal layer provided in the top part of the protrusion part are provided, and at least one part of the metal layer protrudes outside from the side surface of the protrusion part.

  According to this aspect, the connection reliability of the connecting metal to the protrusion is improved due to the presence of the metal layer protruding from the side surface of the protrusion.

  In the above aspect, irregularities may be formed on the side surfaces of the protrusions.

  In the above aspect, the metal layer may be a Ni / Au layer, and the Ni layer may be in contact with the protrusion.

  Yet another embodiment of the present invention is a semiconductor module. This semiconductor module includes the element mounting substrate according to any one of the aspects described above and a semiconductor element mounted on the element mounting substrate.

  In the above aspect, the element mounting substrate has a protruding electrode that is electrically connected to the wiring layer and protrudes from the wiring layer to the insulating resin layer side, and the semiconductor element has an element electrode facing the protruding electrode. The protruding electrode may penetrate the insulating resin layer, and the protruding electrode and the element electrode may be electrically connected.

  Yet another embodiment of the present invention is a portable device. This portable device is equipped with the semiconductor module according to any one of the above-described aspects.

  Yet another embodiment of the present invention is a method for manufacturing an element mounting substrate. The element mounting substrate manufacturing method includes a step of laminating a metal layer at a predetermined position on the metal plate where the protrusions are formed, and selectively removing the surface of the metal plate using the metal layer as a mask. Forming a protrusion and causing at least a part of the metal layer to protrude outward from a side surface of the protrusion.

  Still another embodiment of the present invention is a method for manufacturing a semiconductor module. The manufacturing method of the semiconductor module includes a step of preparing a metal plate in which a protruding electrode is protruded on one main surface and a metal layer is laminated at a predetermined position on the other main surface where a protruding portion is formed; A plate and a semiconductor element provided with an element electrode corresponding to the protruding electrode are pressure-bonded via an insulating resin layer, and the protruding electrode penetrates the insulating resin layer, thereby electrically connecting the protruding electrode and the element electrode. A crimping step of connecting, a step of selectively removing the other main surface using the metal layer as a mask, and forming a protrusion and projecting at least a part of the metal layer outward from the side surface of the protrusion; Covering at least part of the side surface of the protrusion and the metal layer with a connecting metal.

  According to the present invention, by using the metal layer as a mask when forming the protrusion on the wiring layer, the formation cost is reduced and the connection reliability of the connecting metal to the protrusion is improved.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing a configuration of an element mounting substrate 10 and a semiconductor module 30 using the same according to the first embodiment. The semiconductor module 30 includes an element mounting substrate 10 and a semiconductor element 50 mounted thereon.

  The element mounting substrate 10 is electrically connected to the insulating resin layer 12 made of an insulating resin, the wiring layer 14 provided on one main surface S1 of the insulating resin layer 12, and the wiring layer 14, Covers the protrusion 16 projecting from the wiring layer 14 on the opposite side of the insulating resin layer 12, the metal layer 17 provided in contact with the top surface of the protrusion 16, the side surface of the protrusion 16 and the metal layer 17. And a low melting point metal ball 18.

  The insulating resin layer 12 is made of an insulating resin, and is formed of a material that causes plastic flow when pressed, for example. An example of a material that causes plastic flow when pressed is an epoxy thermosetting resin. The epoxy thermosetting resin used for the insulating resin layer 12 may be any material having a viscosity of 1 kPa · s under conditions of a temperature of 160 ° C. and a pressure of 8 Mpa, for example. Moreover, this epoxy-type thermosetting resin, for example, when the pressure is increased at 5 to 15 Mpa under the condition of a temperature of 160 ° C., the viscosity of the resin is reduced to about 1/8 compared with the case where no pressure is applied. Is. On the other hand, the B stage epoxy resin before thermosetting is not as viscous as when the resin is not pressurized under the condition of the glass transition temperature Tg or lower, and does not cause viscosity even when pressurized.

  The wiring layer 14 is provided on one main surface S1 of the insulating resin layer 12, and is formed of a conductive material, preferably a rolled metal, and further rolled copper. Or you may form with electrolytic copper. On the wiring layer 14, a protrusion 16 is integrally provided on the side opposite to the insulating resin layer 12. Therefore, the protrusion 16 is also made of the same conductive material as that of the wiring layer 14, for example, a rolled metal. The projecting position of the projecting portion 16 is, for example, a position that is routed by rewiring.

  The protrusion 16 is for supporting a connecting metal such as a low melting point metal ball (for example, a solder ball) for electrical connection with a printed wiring board or the like. When the low melting point metal ball 18 is provided in the protruding region of the protrusion 16, the side surface of the protrusion 16 and the entire metal layer 17 are covered with the low melting point metal ball 18, and the low melting point metal ball 18 is covered with the protrusion 16. And supported by the metal layer 17. Therefore, the height from the main surface of the wiring layer 14 to the apex of the low melting point metal ball 18 (hereinafter referred to as the ball height) is kept high.

  The protrusion 16 has a round shape in a plan view, for example, and the side surface thereof has a tapered shape whose diameter decreases from the main surface of the wiring layer 14 toward the top of the protrusion 16. Since the side surface of the protrusion 16 has a tapered shape, the contact area between the protrusion 16 and the low melting point metal ball 18 increases, so that the ball height can be kept high. The shape of the protrusion 16 is not particularly limited, and may be, for example, a cylindrical shape having a predetermined diameter, or a polygon such as a quadrangle in plan view. Furthermore, the side surface of the protrusion 16 in a cross-sectional view may have a curved shape (for example, Mt. Fuji) whose curvature changes. In addition, predetermined unevenness may be formed on the side surface of the protruding portion 16. Here, the predetermined unevenness means that the bonding strength between the protrusion 16 and the low melting point metal ball 18 can be increased by an anchor effect. The irregularities are, for example, irregularities in the range of 0.5 to 3.0 μm (0.5 μm or more and 3.0 μm or less) in terms of ten-point average roughness (Rz). When the unevenness is smaller than 0.5 μm in Rz, a desired anchor effect that can increase the bonding strength between the protrusion 16 and the low melting point metal ball 18 cannot be obtained. Further, when the unevenness is larger than 3.0 μm in Rz, the low melting point metal ball 18 cannot enter the recess, and there is a possibility that a space is formed between the low melting point metal ball 18 and the protrusion 16. is there. As a result, the low melting point metal ball 18 is easily peeled off from the protrusion 16 when thermal stress occurs. Therefore, the unevenness is preferably within the above range. The degree of unevenness may be determined by experiment.

  The metal layer 17 is provided in contact with the top surface of the top of the protrusion 16. The end portion of the metal layer 17 protrudes outward from the side surface of the protruding portion 16, and at least a part of the metal layer 17 is formed on the protruding portion 16 in order to improve the connection reliability of the low melting point metal ball 18 to the protruding portion 16. It needs to protrude outward from the side. With such a structure, the low-melting point metal ball 18 that has turned below the protruding portion of the metal layer 17 is locked to the protruding portion of the metal layer 17. Therefore, even if a force is applied to the low melting point metal ball 18 in the horizontal direction and / or the vertical direction, it is possible to make the low melting point metal ball 18 difficult to come off from the protrusion 16. It is desirable to provide the metal layer 17 so that the area of the metal layer 17 is larger than the area of the upper surface of the protrusion 16 so as to increase the portion that the low melting point metal ball 18 is locked.

  The metal layer 17 in this embodiment is a Ni (nickel) / Au (gold) layer composed of two upper and lower layers in the direction perpendicular to the wiring layer 14. The upper Au layer is in contact with the low melting point metal ball 18, and the lower Ni layer is in contact with the protrusion 16. Since Au has high wettability with respect to the solder used for the low melting point metal ball 18, the low melting point metal ball 18 is arranged by placing the Au layer on the upper side so that the area in contact with the low melting point metal ball 18 is increased as compared with the Ni layer. It becomes easy to install.

  The side surface of the protrusion 16 may also be coated with a metal layer such as an Au / Ni plating layer formed by, for example, an electrolytic plating method or an electroless plating method. For example, when rolled copper is used for the wiring layer 14 and the protruding portion 16 and a solder ball is used as the low melting point metal ball 18, the protruding portion 16 becomes hollow due to the reaction between copper (Cu) and tin (Sn) in the solder. There is a risk that. In addition, cracks may occur at the interface between copper and solder. Such a phenomenon can be suppressed by covering the protrusion 16 with the metal layer. However, it is necessary that a part of the metal layer 17 protrudes more than the metal layer covered on the side surface so that the low melting point metal ball 18 is locked.

  A protective layer 20 for preventing the wiring layer 14 from being oxidized is provided on the main surface of the wiring layer 14 on the side from which the protrusions 16 protrude. Examples of the protective layer 20 include a solder resist layer. An opening 20a is formed in the protective layer 20 in a region corresponding to the protruding portion 16, and the protective layer 20 is provided so that the protruding portion 16 protrudes from the opening 20a. Although the low melting point metal ball 18 is not in contact with the opening 20a, as shown in FIG. 2, a part thereof may be in contact with the inner surface of the opening 20a. In this case, a part of the low-melting-point metal ball 18 is inserted into a recess surrounded by the inner surface of the opening 20 a of the protective layer 20, the side surface of the protrusion 16, and the surface of the wiring layer 14. Thereby, since the spread of the low melting point metal ball 18 in the direction parallel to the main surface of the wiring layer 14 is suppressed, the ball height can be kept high.

  Further, the element mounting substrate 10 may have a protruding electrode 22 that is electrically connected to the wiring layer 14 and protrudes from the wiring layer 14 to the insulating resin layer 12 side. The protruding electrode 22 is shaped so that its overall shape becomes thinner as it approaches the tip. Further, the side surface of the protruding electrode 22 in a cross-sectional view may have a curved shape (for example, Mt. Fuji) whose curvature changes. A metal layer 19 is provided on the lower surface of the top of the protruding electrode 22 in the same manner as the protruding portion 16.

  The semiconductor element 50 is mounted on the element mounting substrate 10 having the above-described configuration, and the semiconductor module 30 is formed. In the semiconductor module 30 of the present embodiment, the metal layer 19 provided on the lower surface of the top of the protruding electrode 22 of the element mounting substrate 10 and the element electrode 52 of the semiconductor element 50 are electrically connected via the insulating resin layer 12. Structure. The structure of the semiconductor module 30 is not particularly limited, and the semiconductor element 50 may be mounted at an arbitrary position on the element mounting substrate 10 by an arbitrary method such as wire bonding. As the metal layer 19, for example, a Ni (nickel) / Au (gold) layer can be used similarly to the metal layer 17.

  The semiconductor element 50 includes element electrodes 52 that face the protruding electrodes 22. In addition, an element protection layer 54 provided so that the element electrode 52 is opened is laminated on the main surface of the semiconductor element 50 on the side in contact with the insulating resin layer 12. Specific examples of the semiconductor element 50 include semiconductor chips such as an integrated circuit (IC) and a large scale integrated circuit (LSI). A specific example of the element protective layer 54 is a polyimide layer. Further, for example, aluminum (Al) is used for the element electrode 52.

  In the present embodiment, the insulating resin layer 12 is provided between the element mounting substrate 10 and the semiconductor element 50, and the element mounting substrate 10 is crimped to one main surface S 1 of the insulating resin layer 12. 50 is crimped to the other main surface. The protruding electrode 22 penetrates the insulating resin layer 12 and is electrically connected to the element electrode 52 provided on the semiconductor element 50. Since the insulating resin layer 12 is made of a material that causes plastic flow when pressed, the insulating resin layer 12 is provided on the lower surface of the top of the protruding electrode 22 in a state where the element mounting substrate 10, the insulating resin layer 12, and the semiconductor element 50 are integrated in this order. The remaining film of the insulating resin layer 12 is suppressed from being interposed between the metal layer 19 and the device electrode 52, and connection reliability is improved.

(Element mounting substrate and semiconductor module manufacturing method)
3A to 3E are process cross-sectional views illustrating a method for forming the metal layer 17, the metal layer 19, and the protruding electrode 22.

  As shown in FIG. 3A, a copper plate 13 is prepared as a metal plate having a thickness that is at least larger than the sum of the heights of the protruding portions 16 and the protruding electrodes 22 and the thickness of the wiring layer 14.

  Next, as shown in FIG. 3B, a resist 70 is selectively formed on the upper and lower surfaces of the copper plate 13 according to the pattern of the protrusions 16 and the protrusion electrodes 22 by lithography. Specifically, a resist film having a predetermined thickness is attached to the copper plate 13 using a laminator device, exposed using a photomask having a pattern of the projections 16 and the projection electrodes 22, and then developed, thereby developing the copper plate 13. A resist 70 is selectively formed on the upper and lower surfaces. In order to improve the adhesion to the resist, it is desirable to perform pretreatment such as polishing and washing on the surface of the copper plate 13 as necessary before laminating the resist film.

  Next, as shown in FIG. 3C, the metal layer 17 corresponding to a predetermined pattern is formed on the upper surface of the copper plate 13 with a predetermined pattern on the lower surface by using, for example, an electrolytic plating method or an electroless plating method with the resist 70 as a mask. A metal layer 19 corresponding to the pattern is formed.

  Next, as shown in FIG. 3D, the resist 70 is stripped using a stripping agent. Further, a resist (not shown) is formed on the entire surface of the copper plate 13 including the metal layer 17 in order to protect the upper surface of the copper plate 13.

  Next, as shown in FIG. 3E, a protruding electrode 22 having a predetermined pattern is formed on the lower surface of the copper plate 13 using the metal layer 19 as a mask. Specifically, the bump electrode 22 having a predetermined pattern is formed by etching the copper plate 13 using the metal layer 19 as a mask. Since a resist (not shown) is formed on the upper surface of the copper plate 13, the metal layer 17 does not function as a mask by this etching. After the formation of the protruding electrode 22, the resist (not shown) on the upper surface of the copper plate 13 is peeled off using a peeling agent.

  The protruding electrode 22 is formed by the process described above. The diameter of the base portion, the diameter of the tip portion, and the height of the protruding electrode 22 of the present embodiment are, for example, 40 μmφ, 30 μmφ, and 50 μm, respectively.

  4A to 4F are process cross-sectional views illustrating a method for forming the wiring layer 14, the low melting point metal ball 18 and the protrusion 16, and a method for connecting the protrusion electrode 22 and the element electrode 52.

  As shown in FIG. 4A, a copper plate 13 provided with a protective film 15 on the upper surface is disposed on one main surface S1 side of the insulating resin layer 12 in order to eliminate a step due to the metal layer 17. Further, the semiconductor element 50 provided with the element electrode 52 facing the protruding electrode 22 is disposed on the other main surface of the insulating resin layer 12. The thickness of the insulating resin layer 12 is about the height of the protruding electrode 22 and is about 35 μm. And the copper plate 13 and the semiconductor element 50 are crimped | bonded via the insulating resin layer 12 using a press apparatus. By providing the protective film 15, the copper plate 13 can be uniformly pressed downward. The pressure and temperature during pressing are about 5 Mpa and 180 ° C., respectively.

  By press working, the insulating resin layer 12 causes plastic flow, and the protruding electrodes 22 and the metal layer 19 penetrate the insulating resin layer 12. Then, as shown in FIG. 4B, the copper plate 13, the insulating resin layer 12, and the semiconductor element 50 are integrated, the metal layer 19 and the element electrode 52 are pressure-bonded, and the protruding electrode 22 and the element electrode 52 are connected. Electrically connected. Since the protruding electrode 22 has a shape such that its overall shape becomes thinner as it approaches the tip, the protruding electrode 22 smoothly penetrates the insulating resin layer 12. In the present embodiment, the copper plate 13 is pressure-bonded to the insulating resin layer 12, and the copper plate 13 is laminated on one main surface S <b> 1 of the insulating resin layer 12.

  Next, as shown in FIG. 4C, after the protective film 15 is removed, a protrusion 16 having a predetermined pattern is formed on the upper surface of the copper plate 13 using the metal layer 17 as a mask. Specifically, the protrusion 16 having a predetermined pattern is formed by etching the copper plate 13 using the metal layer 17 as a mask. When the protrusion 16 is formed, the etching of the copper plate 13 is adjusted so that the end of the metal layer 17 protrudes outward from the side surface of the protrusion 16. The diameter of the base part, the diameter of the tip part, and the height of the protrusion 16 in the present embodiment are, for example, 150 μmφ, 100 μmφ, and 50 μm, respectively.

  Next, as shown in FIG. 4D, a resist (not shown) is selectively applied to the main surface of the copper plate 13 on the side where the protrusions 16 are formed, according to the pattern of the wiring layer 14 by lithography. Form. Then, the copper plate 13 is etched using the resist as a mask to form a wiring layer 14 having a predetermined pattern on the copper plate 13. Thereafter, the resist is removed. The thickness of the wiring layer 14 in this embodiment is about 20 μm.

  Here, following the formation of the wiring layer 14, predetermined irregularities having a ten-point average roughness (Rz) in the range of 0.5 to 3.0 μm, for example, may be formed on the side surface of the protrusion 16. Good. The unevenness can be formed, for example, by subjecting the surface of the protrusion 16 to a roughening treatment. Examples of the roughening treatment include chemical treatment such as CZ treatment (registered trademark), plasma treatment, and the like. When the protrusion 16 is made of rolled copper, the orientation of the copper crystal grains forming the protrusion 16 is aligned in a direction parallel to the main surface of the wiring layer 14. For this reason, the unevenness | corrugation can be easily formed in the side surface of the projection part 16 by the roughening process of the projection part 16 surface. Further, the wiring layer 14 may be roughened at the same time as the roughening of the protrusions 16. In this case, irregularities are also formed on the surface of the wiring layer 14, and the bonding strength between the protective layer 20 and the wiring layer 14 formed in the next step can be increased by the anchor effect.

  Next, as shown in FIG. 4E, the main surface of the wiring layer 14 on the side from which the protruding portion 16 protrudes is formed by forming the protective layer 20 in the region corresponding to the protruding portion 16 by lithography. Further, the protrusion 16 is formed so as to protrude from the opening 20a.

  Next, as shown in FIG. 4F, low-melting point metal balls 18 are formed on the protrusions 16 by using, for example, a solder printing method. Specifically, for example, a low-melting-point metal ball 18 is formed by printing a solder paste made of a resin and a solder material in a paste form at a desired location using a screen mask and heating to a solder melting temperature. Alternatively, as another method, flux may be applied in advance to the wiring layer 14 side, and the low melting point metal ball 18 may be mounted on the wiring layer 14. The low melting point metal ball 18 covers the entire metal layer 17 and the side surface of the protrusion 16. The diameter of the low melting point metal ball 18 in the present embodiment in the direction parallel to the wiring layer 14 is about 160 to 250 μm, and the ball height is about 140 μm when mounted on the printed wiring board.

  In order to manufacture the semiconductor module 30 shown in FIG. 2, a protective film may be formed so that the distance between the inner surface of the opening 20a and the protrusion 16 is closer in FIG. Further, it may be formed by increasing the amount of solder paste printed on the protrusion 16 in FIG. The low melting point metal ball 18 formed in this manner covers the entire side surface of the protrusion 16 and a part thereof is in contact with the inner surface of the opening 20a. Thereby, since the spread of the low melting point metal ball 18 in the direction parallel to the main surface of the wiring layer 14 is suppressed, the ball height can be kept high.

  The semiconductor module 30 is formed by the manufacturing process described above. Further, when the semiconductor element 50 is not mounted, the element mounting substrate 10 is obtained.

  As described above, in the element mounting substrate 10 of the present embodiment, the wiring layer 14 and the protrusion 16 are integrally formed. Therefore, even when a stress due to heat is generated, there is little possibility that a crack will occur between the wiring layer 14 and the protrusion 16. Therefore, even when the semiconductor module 30 in which the semiconductor element 50 is mounted on the element mounting substrate 10 is mounted on the printed wiring board, the connection reliability between the semiconductor module 30 and the printed wiring board is improved. Further, unevenness is formed on the side surface of the protruding portion 16 and the bonding strength between the protruding portion 16 and the low melting point metal ball 18 is increased, so that the connection reliability is further improved.

  Further, since the low melting point metal ball 18 is supported by the protrusion 16 and the metal layer 17, the ball height can be kept high. Further, in the semiconductor module 30 as shown in FIG. 2, a part of the low melting point metal ball 18 is in contact with the inner side surface of the opening 20 a and is parallel to the main surface of the wiring layer 14 of the low melting point metal ball 18. Therefore, the height of the ball can be kept higher. Since the ball height is kept high, it is possible to reduce the pitch between the electrodes of the semiconductor module 30 for mounting on the printed wiring board, and to the printed wiring board of the semiconductor module 30 in the structure with the fine pitch. Mounting reliability is improved.

  Further, since the end portion of the metal layer 17 protrudes outward from the side surface of the protruding portion 16, the low melting point metal ball 18 is locked to the end portion of the metal layer 17, and the low melting point metal ball 18 is detached from the protruding portion 16. It becomes difficult. Therefore, the bonding strength between the protrusion 16 and the low melting point metal ball 18 is increased, and the connection reliability is further improved. Thus, since the copper plate 13 can be etched using the metal layer 17 contributing to the improvement of connection reliability as a mask, the manufacturing process is further simplified, and the manufacturing cost of the semiconductor module 30 can be reduced.

(Embodiment 2)
In Embodiment 1 described above, the end of the metal layer 17 provided on the top surface of the protrusion 16 protrudes from the side surface of the protrusion 16 in a direction parallel to the wiring layer 14, but as shown in FIG. The protrusion 16 may protrude along the side surface. In the present embodiment, a semiconductor module 30 including such a metal layer 17 will be described. In addition, the same code | symbol is attached | subjected about the structure same as Embodiment 1, and the description is abbreviate | omitted.

  FIG. 5 is a schematic cross-sectional view showing the configuration of the element mounting substrate 10 according to the second embodiment and the semiconductor module 30 using the same. The semiconductor module 30 includes an element mounting substrate 10 and a semiconductor element 50 mounted thereon.

  The end of the metal layer 17 protrudes from the side surface of the protrusion 16 so as to cover the top side surface of the protrusion 16. Thereby, the top surface and the top side surface of the protrusion 16 are covered with the metal layer 17. Therefore, as in the first embodiment, since the low melting point metal ball 18 that wraps around below the protruding portion of the metal layer 17 is locked to the protruding portion, the low melting point metal ball 18 is horizontally and / or vertically oriented. Even if force is applied, the low melting point metal ball 18 is unlikely to be detached from the protrusion 16. Since the bonding strength between the protrusion 16 and the low melting point metal ball 18 is increased, the connection reliability is further improved.

(Element mounting substrate and semiconductor module manufacturing method)
6A to 6D are process cross-sectional views illustrating a method for forming the protruding electrode 22.

  As shown in FIG. 6A, a copper plate 13 is prepared as a metal plate having a thickness that is at least greater than the sum of the heights of the projections 16 and the projection electrodes 22 and the thickness of the wiring layer 14.

  Next, as shown in FIG. 6B, a resist 70 is selectively formed on the upper surface of the copper plate 13 in accordance with the pattern of the protruding electrodes 22 by lithography. Specifically, a resist film having a predetermined film thickness is attached to the copper plate 13 using a laminator device, exposed using a photomask having a pattern of the protruding electrodes 22, and then developed to form a resist on the copper plate 13. 70 is selectively formed. In order to improve the adhesion to the resist, it is desirable to perform pretreatment such as polishing and washing on the surface of the copper plate 13 as necessary before laminating the resist film. Further, a resist (not shown) is formed on the entire lower surface of the copper plate 13 in order to protect the lower surface of the copper plate 13.

  Next, as shown in FIG. 6C, a bump electrode 22 having a predetermined pattern is formed on the copper plate 13 using the resist 70 as a mask. Specifically, the bump electrode 22 having a predetermined pattern is formed by etching the copper plate 13 using the resist 70 as a mask. Since a resist (not shown) is formed on the lower surface of the copper plate 13, the lower surface of the copper plate 13 is protected from this etching. After the formation of the protruding electrode 22, the resist (not shown) on the lower surface of the copper plate 13 is peeled off using a peeling agent.

  Next, as shown in FIG. 6D, the resist 70 is stripped using a stripping agent. The protruding electrode 22 is formed by the process described above. The diameter of the base portion, the diameter of the tip portion, and the height of the protruding electrode 22 of the present embodiment are, for example, 40 μmφ, 30 μmφ, and 50 μm, respectively. In addition, although the lower surface of the copper plate 13 is protected using a resist, the thickness of the copper plate 13 is adjusted by etching shown in FIG. 6C (for example, the thickness is reduced by etching the lower surface of the copper plate 13). In this case, it is not necessary to form a resist on the lower surface of the copper plate 13.

  7A to 7F are process cross-sectional views illustrating a method for forming the wiring layer 14, the metal layer 17, and the low melting point metal ball 18 and a method for connecting the protruding electrode 22 and the element electrode 52.

  As shown in FIG. 7A, the copper plate 13 is disposed on one main surface S1 side of the insulating resin layer 12 so that the protruding electrodes 22 face the insulating resin layer 12 side. Further, the semiconductor element 50 provided with the element electrode 52 facing the protruding electrode 22 is disposed on the other main surface of the insulating resin layer 12. The thickness of the insulating resin layer 12 is about the height of the protruding electrode 22 and is about 35 μm. And the copper plate 13 and the semiconductor element 50 are crimped | bonded via the insulating resin layer 12 using a press apparatus. The pressure and temperature during pressing are about 5 Mpa and 180 ° C., respectively.

  By press working, the insulating resin layer 12 causes plastic flow, and the protruding electrodes 22 penetrate the insulating resin layer 12. Then, as shown in FIG. 7B, the copper plate 13, the insulating resin layer 12, and the semiconductor element 50 are integrated, and the protruding electrode 22 and the element electrode 52 are pressure-bonded so that the protruding electrode 22 and the element electrode 52 are connected. Electrically connected. Since the protruding electrode 22 has a shape such that its overall shape becomes thinner as it approaches the tip, the protruding electrode 22 smoothly penetrates the insulating resin layer 12. In the present embodiment, the copper plate 13 is pressure-bonded to the insulating resin layer 12, and the copper plate 13 is laminated on one main surface S <b> 1 of the insulating resin layer 12.

  Next, as shown in FIG. 7C, a resist (not shown) is selectively applied to the main surface of the copper plate 13 opposite to the insulating resin layer 12 according to the pattern of the protrusions 16 by lithography. Form. Then, the main surface of the copper plate 13 is etched using the resist as a mask to form the protrusions 16 having a predetermined pattern on the copper plate 13. Thereafter, the resist is removed. The diameter of the base part, the diameter of the tip part, and the height of the protrusion 16 in the present embodiment are, for example, 150 μmφ, 100 μmφ, and 50 μm, respectively.

  After forming the projections 16, the protective film 21 is formed by a lithography method so as to cover a region excluding the top surface and the top side surface of the projections 16.

  Next, as shown in FIG. 7D, a metal layer 17 is formed on the top surface and the top side surface of the protruding portion 16 protruding from the protective film 21 and exposed by, for example, an electrolytic plating method or an electroless plating method.

  Next, as shown in FIG. 7E, the protective film 21 is removed so that the top surface and top side surface of the protrusion 16 are covered with the metal layer 17.

  Next, as shown in FIG. 7F, a wiring layer 14 having a predetermined pattern is formed on the copper plate 13 by lithography, as in FIG. 4D. The thickness of the wiring layer 14 in this embodiment is about 20 μm. Further, as in FIG. 4E, a protective layer 20 having an opening 20a formed in a region corresponding to the protrusion 16 is formed on the main surface of the wiring layer 14 on the side from which the protrusion 16 protrudes by lithography. The protrusion 16 is formed so as to protrude from the opening 20a.

  Further, as in FIG. 4F, the low melting point metal ball 18 is formed on the protrusion 16 by using, for example, a solder printing method. The low melting point metal ball 18 covers the entire side surface of the metal layer 17 and the protrusion 16. The diameter of the low melting point metal ball 18 in the present embodiment in the direction parallel to the wiring layer 14 is about 160 to 250 μm, and the ball height is about 140 μm when mounted on the printed wiring board.

  Also in this embodiment, as shown in FIG. 2, the low melting point metal ball 18 may be in contact with the inner surface of the opening 20a, and can be manufactured by the same method as the manufacturing method of FIG. In addition, as in the first embodiment, the unevenness may be formed by performing a roughening process on the side surface of the protrusion 16 that is not covered with the metal layer 17. Further, the protruding electrode 22 may be formed by a method using the metal layer 19 as a mask, as in the first embodiment.

  The semiconductor module 30 is formed by the manufacturing process described above. Further, when the semiconductor element 50 is not mounted, the element mounting substrate 10 is obtained.

  Similar to the first embodiment, the element mounting substrate 10 of the present embodiment integrally forms the wiring layer 14 and the protrusion 16. Therefore, even when a stress due to heat is generated, there is little possibility that a crack will occur between the wiring layer 14 and the protrusion 16. Therefore, even when the semiconductor module 30 in which the semiconductor element 50 is mounted on the element mounting substrate 10 is mounted on the printed wiring board, the connection reliability between the semiconductor module 30 and the printed wiring board is improved. Further, when unevenness is formed on the side surface of the protrusion 16, the bonding strength between the protrusion 16 and the low melting point metal ball 18 is increased, so that the connection reliability is further improved.

  Further, since the low melting point metal ball 18 is supported by the protrusion 16 and the metal layer 17, the ball height can be kept high. Further, in the semiconductor module 30 as shown in FIG. 2, a part of the low melting point metal ball 18 is in contact with the inner side surface of the opening 20 a and is parallel to the main surface of the wiring layer 14 of the low melting point metal ball 18. Therefore, the height of the ball can be kept higher. Since the ball height is kept high, it is possible to reduce the pitch between the electrodes of the semiconductor module 30 for mounting on the printed wiring board, and to the printed wiring board of the semiconductor module 30 in the structure with the fine pitch. Mounting reliability is improved.

(Embodiment 3)
In the first embodiment described above, the metal layer 17 is provided in contact with the top surface of the protrusion 16, but the side surface of the top without contacting the top surface of the protrusion 16 as shown in FIG. 8. It may protrude so as to cover only. In the present embodiment, a semiconductor module 30 including such a metal layer 17 will be described. In addition, the same code | symbol is attached | subjected about the structure same as Embodiment 1, and the description is abbreviate | omitted.

  FIG. 8 is a schematic cross-sectional view showing configurations of the element mounting substrate 10 and the semiconductor module 30 using the same according to the third embodiment. The semiconductor module 30 includes an element mounting substrate 10 and a semiconductor element 50 mounted thereon.

  The metal layer 17 covers only the top side surface of the protrusion 16 without contacting the top surface of the protrusion 16, and protrudes outward from the side surface of the protrusion 16. As a result, as in the first embodiment, the low melting point metal ball 18 that wraps around below the protruding portion of the metal layer 17 is locked to the protruding portion, so that the horizontal direction and / or the vertical direction with respect to the low melting point metal ball 18. Even if a force is applied to the low melting point metal ball 18, it is difficult for the low melting point metal ball 18 to be detached from the protrusion 16. Since the bonding strength between the protrusion 16 and the low melting point metal ball 18 is increased, the connection reliability is further improved.

(Element mounting substrate and semiconductor module manufacturing method)
9A and 9B are process cross-sectional views illustrating a method for forming the wiring layer 14, the metal layer 17, and the low melting point metal ball 18.

  7A to 7E, a state in which the top surface and the top side surface of the protrusion 16 are covered with the metal layer 17 is manufactured.

  Next, as shown in FIG. 9A, the metal layer 17 in contact with the top surface of the protrusion 16 is removed by polishing using CMP (Chemical Mechanical Polishing), and the top surface of the top of the protrusion 16 is removed. To expose.

  Next, as shown in FIG. 9B, a wiring layer 14 having a predetermined pattern is formed on the copper plate 13 by lithography, as in FIG. 4D. The thickness of the wiring layer 14 in this embodiment is about 20 μm. Further, as in FIG. 4E, a protective layer 20 having an opening 20a formed in a region corresponding to the protrusion 16 is formed on the main surface of the wiring layer 14 on the side from which the protrusion 16 protrudes by lithography. The protrusion 16 is formed so as to protrude from the opening 20a.

  Further, as in FIG. 4F, the low melting point metal ball 18 is formed on the protrusion 16 by using, for example, a solder printing method. The low-melting-point metal ball 18 covers the top surface of the protrusion 16, the metal layer 17, and the entire side surface of the protrusion 16. The diameter of the low melting point metal ball 18 in the present embodiment in the direction parallel to the wiring layer 14 is about 160 to 250 μm, and the ball height is about 140 μm when mounted on the printed wiring board.

  Also in this embodiment, as shown in FIG. 2, the low melting point metal ball 18 may be in contact with the inner surface of the opening 20a, and can be manufactured by the same method as the manufacturing method of FIG. In addition, as in the first embodiment, the unevenness may be formed by performing a roughening process on the side surface of the protrusion 16 that is not covered with the metal layer 17. Further, the protruding electrode 22 may be formed by a method using the metal layer 19 as a mask, as in the first embodiment.

  The semiconductor module 30 is formed by the manufacturing process described above. Further, when the semiconductor element 50 is not mounted, the element mounting substrate 10 is obtained.

  Similar to the first embodiment, the element mounting substrate 10 of the present embodiment integrally forms the wiring layer 14 and the protrusion 16. Therefore, even when a stress due to heat is generated, there is little possibility that a crack will occur between the wiring layer 14 and the protrusion 16. Therefore, even when the semiconductor module 30 in which the semiconductor element 50 is mounted on the element mounting substrate 10 is mounted on the printed wiring board, the connection reliability between the semiconductor module 30 and the printed wiring board is improved. Further, when unevenness is formed on the side surface of the protrusion 16, the bonding strength between the protrusion 16 and the low melting point metal ball 18 is increased, so that the connection reliability is further improved.

  Further, since the low melting point metal ball 18 is supported by the protrusion 16 and the metal layer 17, the ball height can be kept high. Further, in the semiconductor module 30 as shown in FIG. 2, a part of the low melting point metal ball 18 is in contact with the inner side surface of the opening 20 a and is parallel to the main surface of the wiring layer 14 of the low melting point metal ball 18. Therefore, the height of the ball can be kept higher. Since the ball height is kept high, it is possible to reduce the pitch between the electrodes of the semiconductor module 30 for mounting on the printed wiring board, and to the printed wiring board of the semiconductor module 30 in the structure with the fine pitch. Mounting reliability is improved.

(Embodiment 4)
Next, a portable device provided with the semiconductor module of the present invention will be described. In addition, although the example mounted in a mobile telephone is shown as a portable apparatus, electronic devices, such as a personal digital assistant (PDA), a digital video camera (DVC), and a digital still camera (DSC), may be sufficient, for example.

  FIG. 10 is a diagram showing a configuration of a mobile phone including the semiconductor module 30 according to the embodiment of the present invention. The mobile phone 111 has a structure in which a first housing 112 and a second housing 114 are connected by a movable portion 120. The first housing 112 and the second housing 114 can be rotated about the movable portion 120 as an axis. The first housing 112 is provided with a display unit 118 and a speaker unit 124 that display information such as characters and images. The second housing 114 is provided with an operation unit 122 such as operation buttons and a microphone unit 126. The semiconductor module 30 according to each embodiment of the present invention is mounted inside such a mobile phone 111.

  FIG. 11 is a partial cross-sectional view (cross-sectional view of the first casing 112) of the mobile phone shown in FIG. The semiconductor module 30 according to each embodiment of the present invention is mounted on the printed wiring board 128 via the low melting point metal ball 18 and is electrically connected to the display unit 118 and the like via the printed wiring board 128. Further, a heat radiating substrate 116 such as a metal substrate is provided on the back side of the semiconductor module 30 (the surface opposite to the low melting point metal ball 18), and for example, heat generated from the semiconductor module 30 is transferred to the first housing 112. The heat can be efficiently radiated to the outside of the first housing 112 without causing any internal fog.

  According to the semiconductor module 30 according to each embodiment of the present invention, since the connection reliability between the semiconductor module 30 and the printed wiring board is improved, the portable device according to the present embodiment on which the semiconductor module 30 is mounted is described. , Improve its reliability.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art, and the embodiments to which such modifications are added are also possible. It can be included in the scope of the present invention.

  For example, in each of the above-described embodiments, the wiring layer is a single layer, but is not limited to this, and the wiring layer may be a multilayer.

  Further, in each of the above-described embodiments, the low melting point metal ball is exemplified as an example of the connection metal of the present application, but the shape is not limited to the ball shape. For convenience, the expression “ball height” is used, but it is not limited to the ball shape.

  In the above-described embodiments, only one protrusion 16 is shown, but a plurality of protrusions 16 may be formed on the wiring layer 14. Further, in each of the above-described embodiments, the metal layer 17 is completely covered with the low melting point metal ball 18, but if the low melting point metal ball 18 is locked to the protruding portion of the metal layer 17, the metal layer 17 is partially made of metal. Layer 17 may be exposed.

  Furthermore, the configuration of the present invention can be applied to a semiconductor package manufacturing process called a wafer level CSP (Chip Size Package) process. According to this, the semiconductor module can be reduced in thickness and size.

It is a schematic sectional drawing which shows the structure of the element mounting substrate which concerns on Embodiment 1, and a semiconductor module using the same. It is a schematic sectional drawing which shows the structure of a semiconductor module in case the low melting metal ball is contact | abutting to the inner surface of an opening part. It is process sectional drawing which shows the formation method of a metal layer, a metal layer, and a protruding electrode. It is process sectional drawing which shows the formation method of a wiring layer, a low melting metal ball | bowl, and a projection part, and the connection method of a projection electrode and an element electrode. It is a schematic sectional drawing which shows the structure of the element mounting substrate which concerns on Embodiment 2, and a semiconductor module using the same. It is process sectional drawing which shows the formation method of a protruding electrode. It is process sectional drawing which shows the formation method of a wiring layer, a metal layer, a low melting-point metal ball | bowl, and the connection method of a protruding electrode and an element electrode. It is a schematic sectional drawing which shows the structure of the element mounting board | substrate which concerns on Embodiment 3, and a semiconductor module using the same. It is process sectional drawing which shows the formation method of a wiring layer, a metal layer, and a low melting metal ball. 6 is a diagram illustrating a configuration of a mobile phone according to Embodiment 4. FIG. It is a fragmentary sectional view of a mobile phone.

Explanation of symbols

  10 element mounting substrate, 12 insulating resin layer, 13 copper plate, 14 wiring layer, 15 protective film, 16 protrusion, 17 metal layer, 18 low melting point metal ball, 19 metal layer, 20 protective layer, 20a opening, 21 protection Membrane, 22 Projection electrode, 30 Semiconductor module, 50 Semiconductor element, 52 Element electrode, 54 Element protective layer, 70 Resist.

Claims (9)

A wiring layer;
A protrusion that is electrically connected to the wiring layer and protrudes from the wiring layer;
A metal layer provided on the top of the protrusion,
A connecting metal covering at least a part of the side surface of the protruding portion and the metal layer;
With
At least a part of the metal layer protrudes outward from a side surface of the protrusion. An insulating resin layer;
A wiring layer provided on one main surface of the insulating resin layer;
A protrusion that is electrically connected to the wiring layer and protrudes from the wiring layer to the side opposite to the insulating resin layer;
A metal layer provided on the top of the protrusion,
With
At least a part of the metal layer protrudes outward from a side surface of the protruding portion.   The element mounting substrate according to claim 2, wherein unevenness is formed on a side surface of the protrusion.   The element mounting substrate according to claim 3, wherein the metal layer is a Ni / Au layer, and the Ni layer is in contact with the protrusion. The element mounting substrate according to any one of claims 2 to 4,
A semiconductor element mounted on the element mounting substrate;
A semiconductor module comprising: The element mounting substrate has a protruding electrode that is electrically connected to the wiring layer and protrudes from the wiring layer to the insulating resin layer side,
The semiconductor element has an element electrode facing the protruding electrode,
6. The semiconductor module according to claim 5, wherein the protruding electrode penetrates the insulating resin layer, and the protruding electrode and the element electrode are electrically connected.   A portable device comprising the semiconductor module according to claim 5. A step of laminating a metal layer at a predetermined position on the metal plate where the protrusion is formed;
Selectively removing the surface of the metal plate using the metal layer as a mask to form the protrusion and projecting at least part of the metal layer outward from the side surface of the protrusion;
A method for manufacturing an element mounting board, comprising: A step of preparing a metal plate in which a protruding electrode is projected on one main surface and a metal layer is laminated at a predetermined position on the other main surface where a protruding portion is formed;
The metal plate and a semiconductor element provided with an element electrode corresponding to the protruding electrode are pressure-bonded via an insulating resin layer, and the protruding electrode penetrates the insulating resin layer. A crimping step for electrically connecting the device electrodes;
Selectively removing the other main surface using the metal layer as a mask to form the protrusion and projecting at least a part of the metal layer outward from a side surface of the protrusion;
Coating at least part of the side surface of the protrusion and the metal layer with a connecting metal;
A method for manufacturing a semiconductor module, comprising:

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