Connection structure, semiconductor device and method for manufacturing connection structure

Abstract

To provide a connection structure and a semiconductor device capable of suppressing adjacent connection terminals from being short-circuited.SOLUTION: A semiconductor device 10 has: a first connection terminal 30; a second connection terminal 50 opposed to the first connection terminal 30; and a junction member 60 for bonding between the first connection terminal 30 and the second connection terminal 50. The junction member 60 has an intermetallic compound layer 70 formed by: a roughening copper metal film 80 that has such a structure that deposits 81 formed of a metal are superimposed in a mutually intersecting manner, and has many voids therein; and a solder layer entering into the voids of the roughening copper metal film 80.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a connection structure, a semiconductor device, and a method for manufacturing the connection structure. [Background technology]

[0002] BACKGROUND ART Conventionally, semiconductor devices have been known in which electrode pads of a semiconductor element and connection terminals of a wiring board are joined by a solder layer (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-93547 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the pitch of connection terminals on wiring boards has been narrowed as semiconductor devices have become more sophisticated. However, as the pitch of connection terminals becomes narrower, adjacent solder layers are more likely to short-circuit after reflow. If adjacent solder layers short-circuit, this can lead to the problem of adjacent connection terminals shorting out. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a semiconductor device comprising a first connection terminal, a second connection terminal opposed to the first connection terminal, and a joining member joining the first connection terminal and the second connection terminal, wherein the joining member has an intermetallic compound layer formed of a roughened metal film having a structure in which metal deposits intersect and overlap and having a large number of voids therein, and a solder layer that has entered the voids. The intermetallic compound layer has a structure in which a first intermetallic compound layer and a second intermetallic compound layer different from the first intermetallic compound layer are stacked in the thickness direction of the joining members. . [Effects of the Invention]

[0006] According to one aspect of the present invention, it is possible to suppress short circuits between adjacent connection terminals. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view showing a semiconductor device according to a first embodiment. [Figure 2] 1 is a schematic cross-sectional view showing a part of a semiconductor device according to a first embodiment. [Figure 3] 1 is a schematic exploded cross-sectional view showing a part of a semiconductor device according to a first embodiment. [Figure 4] 2A to 2C are schematic cross-sectional views illustrating a method for manufacturing the semiconductor device of the first embodiment. [Figure 5] 2A to 2C are schematic cross-sectional views illustrating a method for manufacturing the semiconductor device of the first embodiment. [Figure 6] 2A to 2C are schematic cross-sectional views illustrating a method for manufacturing the semiconductor device of the first embodiment. [Figure 7] 2A to 2C are schematic cross-sectional views illustrating a method for manufacturing the semiconductor device of the first embodiment. [Figure 8] 5A to 5C are schematic cross-sectional views showing a method for manufacturing a semiconductor device according to a second embodiment. [Figure 9] 5A to 5C are schematic cross-sectional views showing a method for manufacturing a semiconductor device according to a second embodiment. [Figure 10] 5A to 5C are schematic cross-sectional views showing a method for manufacturing a semiconductor device according to a second embodiment. [Figure 11] FIG. 10 is a schematic cross-sectional view showing a semiconductor device according to a third embodiment. [Figure 12] FIG. 10 is a schematic cross-sectional view showing a part of a semiconductor device according to a third embodiment. [Figure 13] FIG. 10 is a schematic exploded cross-sectional view showing a part of a semiconductor device according to a third embodiment. [Figure 14] FIG. 10 is a schematic exploded cross-sectional view showing a semiconductor device according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Each embodiment will be described below with reference to the accompanying drawings. For convenience, the accompanying drawings may show characteristic portions enlarged to make the features more clearly visible, and the dimensional proportions of each component may differ between drawings. In cross-sectional views, the hatching of some components is replaced with a matte finish, and the hatching of some components is omitted, to make the cross-sectional structure of each component more clearly visible. In this specification, "plan view" refers to viewing an object from the vertical direction (the up-down direction in the drawing) as in Figure 1, and "planar shape" refers to the shape of an object viewed from the vertical direction as in Figure 1. The terms "up-down direction" and "left-right direction" in this specification refer to directions in which the symbols indicating each component in each drawing can be correctly read, assuming the correct position. In this specification, "parallel," "orthogonal," and "vertical" refer not only to strictly parallel, orthogonal, and vertical, but also to roughly parallel, orthogonal, and vertical within the scope of the effects of this embodiment.

[0009] (First embodiment) The first embodiment will be described below with reference to FIGS. (Overall configuration of semiconductor device 10) 1, the semiconductor device 10 has a wiring substrate 20 and one or more (here, one) semiconductor elements 40. The wiring substrate 20 has a first connection terminal 30. The semiconductor element 40 has a second connection terminal 50 that faces the first connection terminal 30. The semiconductor device 10 has a bonding member 60 that bonds the first connection terminal 30 and the second connection terminal 50. The semiconductor device 10 has, for example, an external connection terminal 100.

[0010] (Overall configuration of wiring board 20) The wiring board 20 has, for example, a substrate main body 21. A wiring layer 22 and a solder resist layer 23 are laminated in this order on the lower surface of the substrate main body 21. A wiring layer 24, an insulating layer 25, and a wiring layer 26 are laminated in this order on the upper surface of the substrate main body 21.

[0011] The substrate body 21 may be, for example, a wiring structure in which insulating resin layers and wiring layers are alternately laminated. The wiring structure may or may not have a core substrate. The insulating resin layer may be, for example, a thermosetting insulating resin. Examples of the thermosetting insulating resin include insulating resins such as epoxy resin, polyimide resin, and cyanate resin. The insulating resin layer may also be, for example, an insulating resin whose main component is a photosensitive resin such as a phenolic resin or polyimide resin. The insulating resin layer may contain a filler such as silica or alumina.

[0012] The wiring layer of the substrate main body 21 and the wiring layers 22 and 24 may be made of, for example, copper (Cu) or a copper alloy. The solder resist layer 23 may be made of, for example, an insulating resin whose main component is a photosensitive resin such as a phenolic resin or a polyimide resin. The solder resist layer 23 may contain a filler such as silica or alumina.

[0013] (Structure of wiring layer 22) The wiring layer 22 is formed on the lower surface of the substrate body 21. The wiring layer 22 is the lowest wiring layer of the wiring substrate 20.

[0014] (Structure of solder resist layer 23) The solder resist layer 23 is laminated on the lower surface of the substrate body 21 so as to cover a part of the wiring layer 22. The solder resist layer 23 is an insulating layer that is the outermost layer of the wiring substrate 20 (here, the bottom layer).

[0015] A plurality of openings 23X are formed in the solder resist layer 23 to expose portions of the lower surface of the wiring layer 22 as external connection pads P1. External connection terminals 100 are connected to the external connection pads P1, which are used when mounting the wiring board 20 on a mounting board such as a motherboard.

[0016] A surface treatment layer is formed, if necessary, on the lower surface of the wiring layer 22 exposed at the bottom of the opening 23X. Examples of the surface treatment layer include a gold (Au) layer, a nickel (Ni) layer / Au layer (a metal layer formed by laminating a Ni layer and an Au layer in this order), and a Ni layer / palladium (Pd) layer / Au layer (a metal layer formed by laminating a Ni layer, a Pd layer, and an Au layer in this order). Other examples of the surface treatment layer include a Ni layer / Pd layer (a metal layer formed by laminating a Ni layer and a Pd layer in this order) and a Pd layer / Au layer (a metal layer formed by laminating a Pd layer and an Au layer in this order). Here, the Au layer is a metal layer made of Au or an Au alloy, the Ni layer is a metal layer made of Ni or an Ni alloy, and the Pd layer is a metal layer made of Pd or a Pd alloy. The Au layer, Ni layer, and Pd layer may be, for example, a metal layer formed by electroless plating (electroless plated layer) or a metal layer formed by electrolytic plating (electroplated layer). The surface treatment layer may be an OSP (organic solderability preservative) film formed by applying an anti-oxidation treatment such as an OSP treatment to the lower surface of the wiring layer 22 exposed in the opening 23X. The OSP film may be an organic coating such as an azole compound or an imidazole compound. When a surface treatment layer is formed on the lower surface of the wiring layer 22, the surface treatment layer functions as the external connection pad P1.

[0017] In this example, an external connection terminal 100 is provided on the underside of the wiring layer 22, but the wiring layer 22 itself exposed in the opening 23X, or if a surface treatment layer is formed on the underside of the wiring layer 22, the surface treatment layer itself may also be used as the external connection terminal.

[0018] (Structure of wiring layer 24) The wiring layer 24 is formed on the upper surface of the substrate body 21. The wiring layer 24 is electrically connected to the wiring layer 22 via, for example, a wiring layer or a through electrode within the substrate body 21.

[0019] (Structure of insulating layer 25) The insulating layer 25 is laminated on the upper surface of the substrate main body 21 so as to cover a portion of the wiring layer 24. The insulating layer 25 is an outermost insulating layer provided on the outermost layer (here, the uppermost layer) of the wiring substrate 20. The insulating layer 25 may be, for example, the same insulating resin layer as the insulating resin layer used in the substrate main body 21. Alternatively, for example, a solder resist layer may be used as the insulating layer 25. For example, the same material as that of the solder resist layer 23 may be used as the material of the solder resist layer.

[0020] An opening 25X is formed in the insulating layer 25, penetrating the insulating layer 25 in the thickness direction (vertical direction in the figure) and exposing a portion of the upper surface of the wiring layer 24. The planar shape of the opening 25X can be set to any shape and size. In this example, the planar shape of the opening 25X is formed in a circular shape. In this example, the opening 25X is formed in a tapered shape such that the opening width (opening diameter) decreases from the upper side (the upper surface side of the insulating layer 25) to the lower side (the wiring layer 24 side) in FIG. 1.

[0021] (Structure of wiring layer 26) The wiring layer 26 is formed on the wiring layer 24 exposed from the opening 25X. The wiring layer 26 has, for example, a via wiring 26V formed in the opening 25X and a first connection terminal 30 electrically connected to the wiring layer 24 through the via wiring 26V and formed on the upper surface of the insulating layer 25. The first connection terminal 30 functions as, for example, an electronic component mounting pad for electrically connecting to an electronic component such as a semiconductor element 40.

[0022] The via wiring 26V is formed, for example, so as to fill the opening 25X. The via wiring 26V is formed in the same shape as the opening 25X. The via wiring 26V is formed, for example, in the shape of an inverted truncated cone in which the diameter of the upper surface is larger than the diameter of the lower surface.

[0023] The first connection terminal 30 is formed, for example, in a columnar shape so as to protrude upward from the upper surface of the insulating layer 25. The first connection terminal 30 is, for example, a metal post. In this example, the first connection terminal 30 is formed in a cylindrical shape. The first connection terminal 30 is, for example, formed integrally with the via wiring 26V. The planar shape of the first connection terminal 30 can be set to any shape and size. The planar shape of the first connection terminal 30 can be, for example, a circle with a diameter in the range of 15 μm to 40 μm. The thickness of the first connection terminal 30 can be, for example, in the range of 2 μm to 50 μm.

[0024] The first connection terminal 30 has a first opposing surface 31 (here, the upper surface) that faces the semiconductor element 40. The first opposing surface 31 of the first connection terminal 30 is formed, for example, as a flat surface. The first opposing surface 31 is formed, for example, so as to extend parallel to the upper surface of the substrate body 21. The first opposing surface 31 is, for example, a smooth surface with few irregularities.

[0025] Here, "facing" in this specification refers to surfaces or components facing each other, and includes not only cases where they are completely facing each other, but also cases where they are partially facing each other. Furthermore, "facing" in this specification includes both cases where a component separate from the two components is interposed between the two components, and cases where nothing is interposed between the two components.

[0026] The via wiring 26V and the first connection terminal 30 may be made of, for example, copper or a copper alloy. The first connection terminal 30 in this example is made of copper. The via wiring 26V and the first connection terminal 30 may be made of, for example, an electroless plated layer or an electrolytic plated layer.

[0027] (Configuration of semiconductor element 40) The semiconductor element 40 has a plurality of second connection terminals 50 formed on the circuit formation surface (here, the lower surface) of the semiconductor element 40. The semiconductor element 40 is flip-chip mounted on the wiring board 20. Specifically, the second connection terminals 50 of the semiconductor element 40 are electrically connected to the first connection terminals 30 of the wiring board 20. The second connection terminals 50 are electrically connected to the first connection terminals 30 via bonding members 60. As a result, the semiconductor element 40 is electrically connected to the first connection terminals 30 via the second connection terminals 50 and the bonding members 60.

[0028] The semiconductor element 40 may be, for example, a logic chip such as a CPU (Central Processing Unit) chip or a GPU (Graphics Processing Unit) chip. The semiconductor element 40 may also be, for example, a memory chip such as a DRAM (Dynamic Random Access Memory) chip, an SRAM (Static Random Access Memory) chip, or a flash memory chip. When multiple semiconductor elements 40 are mounted on the wiring board 20, a logic chip and a memory chip may be combined and mounted on the wiring board 20.

[0029] (Structure of second connection terminal 50) The multiple second connection terminals 50 are provided so as to face the multiple first connection terminals 30, respectively. The second connection terminals 50 are formed, for example, in a columnar shape so as to protrude downward from the circuit formation surface of the semiconductor element 40. The second connection terminals 50 are, for example, metal posts. The second connection terminals 50 in this example are formed in a cylindrical shape. The planar shape of the second connection terminals 50 can be set to any shape and size. The planar shape of the second connection terminals 50 can be, for example, a circular shape with a diameter in the range of 15 μm to 40 μm. The thickness of the second connection terminals 50 can be, for example, in the range of 2 μm to 50 μm.

[0030] The second connection terminal 50 may be made of, for example, copper or a copper alloy. The second connection terminal 50 in this example is made of copper. The second connection terminal 50 may be made of an electroless plated layer or an electrolytic plated layer.

[0031] The second connection terminal 50 has a second opposing surface 51 (here, the lower surface) opposing the first opposing surface 31 of the first connection terminal 30. The second opposing surface 51 of the second connection terminal 50 is formed, for example, as a flat surface. The second opposing surface 51 is formed, for example, so as to extend parallel to the circuit formation surface of the semiconductor element 40. The second opposing surface 51 is, for example, a smooth surface with few irregularities.

[0032] (Structure of Joining Member 60) The joining member 60 is joined to, for example, the first opposing surface 31 of the first connection terminal 30 and also joined to the second opposing surface 51 of the second connection terminal 50. The joining member 60 electrically connects the first connection terminal 30 and the second connection terminal 50.

[0033] As shown in FIG. 2 , the joining member 60 has an intermetallic compound layer 70. For example, most of the joining member 60 is composed of the intermetallic compound layer 70. In the joining member 60 of this example, the intermetallic compound layer 70 is composed of a portion other than the outer edge portion on the first opposing surface 31 side. The intermetallic compound layer 70 has, for example, a portion extending over the entire length in the thickness direction of the joining member 60. In other words, a portion of the intermetallic compound layer 70 extends from the first opposing surface 31 to the second opposing surface 51 in the thickness direction of the joining member 60. The intermetallic compound layer 70 of this example extends over the entire length in the thickness direction of the joining member 60 in the center of the joining member 60 in a plan view.

[0034] The intermetallic compound layer 70 has a structure in which, for example, a first intermetallic compound layer 71 and a second intermetallic compound layer 72 different from the first intermetallic compound layer 71 are stacked in the thickness direction of the joining member 60. The first intermetallic compound layer 71 is made of, for example, an intermetallic compound that is richer in Sn than the second intermetallic compound layer 72. The first intermetallic compound layer 71 is made of, for example, a Cu6Sn5 intermetallic compound. The second intermetallic compound layer 72 is made of, for example, an intermetallic compound that is richer in Cu than the first intermetallic compound layer 71. The second intermetallic compound layer 72 is made of, for example, a Cu3Sn intermetallic compound. The Cu3Sn intermetallic compound has better physical properties, such as resistivity, melting point, Young's modulus, tensile strength, and thermal conductivity, than the Cu6Sn5 intermetallic compound.

[0035] The first intermetallic compound layer 71 is formed, for example, to extend from the second opposing surface 51 toward the first opposing surface 31. The first intermetallic compound layer 71 of the present example is formed in a central portion of the intermetallic compound layer 70 in a plan view so as to extend over the entire length in the thickness direction of the joining member 60. For example, a portion of the first intermetallic compound layer 71 provided at the planar center of the intermetallic compound layer 70 is formed so as to extend from the second opposing surface 51 to the first opposing surface 31. The first intermetallic compound layer 71 is formed, for example, to cover the entire surface of the second opposing surface 51. The first intermetallic compound layer 71 is formed, for example, to cover only a portion of the first opposing surface 31. The first intermetallic compound layer 71 is formed, for example, to cover a central portion of the first opposing surface 31. The first intermetallic compound layer 71 is formed so as to become thinner in the thickness direction of the joining member 60 from the second opposing surface 51 toward the first opposing surface 31.

[0036] The second intermetallic compound layer 72 is formed, for example, so as to be laminated with a portion of the first intermetallic compound layer 71 in the thickness direction of the joining member 60. The second intermetallic compound layer 72 of the present example is formed so as to be laminated with the first intermetallic compound layer 71 at the outer edge portion of the intermetallic compound layer 70 in a plan view. That is, the second intermetallic compound layer 72 of the present example is formed so as to be laminated with the outer edge portion of the lower surface of the first intermetallic compound layer 71. In other words, the second intermetallic compound layer 72 of the present example is provided so as to overlap only the outer edge portion of the first intermetallic compound layer 71 in a plan view. The second intermetallic compound layer 72 is formed, for example, so as to cover a portion of the first opposing surface 31. The second intermetallic compound layer 72 is formed, for example, so as to cover a portion of the first opposing surface 31 that is more outer circumferential than the portion of the first opposing surface 31 that is covered by the first intermetallic compound layer 71. The second intermetallic compound layer 72 is provided, for example, only on the first opposing surface 31 side (the lower side in FIG. 2 ) in the thickness direction of the joining member 60. The second intermetallic compound layer 72 does not cover, for example, the second opposing surface 51. The volume of the second intermetallic compound layer 72 is smaller than the volume of the first intermetallic compound layer 71, for example.

[0037] 3, the bonding member 60 is formed by a roughened copper metal film 80 formed on the first opposing surface 31 of the first connection terminal 30 and a solder layer 90 formed on the second opposing surface 51 of the second connection terminal 50. Here, Fig. 3 shows a cross-sectional structure of a portion of the semiconductor device 10 in a state before the semiconductor element 40 is bonded to the wiring substrate 20, that is, before the first connection terminal 30 and the second connection terminal 50 are bonded. The structures of the roughened copper metal film 80 and the solder layer 90 will be described below.

[0038] (Structure of the roughened copper metal film 80) The roughened copper metal film 80 is formed, for example, so as to cover the entire first opposing surface 31. The roughened copper metal film 80 is formed, for example, so as to expose the side surface of the first connection terminal 30. In other words, the roughened copper metal film 80 is formed, for example, so as to cover only the first opposing surface 31 of the surface of the first connection terminal 30. The thickness (film thickness) of the roughened copper metal film 80 can be, for example, in the range of 1 μm to 5 μm.

[0039] The roughened copper metal film 80 is a plating film whose surface (top and side surfaces, or only the top surface) is roughened. The surface of the roughened copper metal film 80 has a fine uneven structure. The roughened copper metal film 80 has a structure in which copper deposits 81 intersect and overlap on the first opposing surface 31 of the first connection terminal 30. The roughened copper metal film 80 has a structure in which copper plate-shaped deposits 81 intersect and overlap on the first opposing surface 31. The roughened copper metal film 80 is a plating film formed by an electrolytic copper plating method. The roughened copper metal film 80 is, for example, a metal film made of a copper plating film only. Here, "a structure in which deposits 81 made of copper intersect and overlap" refers to a structure (porous structure) in which numerous deposits 81 (electrodeposits) made of copper, the plating metal, intersect and overlap in random directions, forming numerous voids 82 in the metal film (plating film).

[0040] The roughened copper metal film 80 of this embodiment has a structure in which sheet-like (thin plate-like) deposits 81 made of copper are folded in various directions, and voids 82 are formed between the sheet-like deposits 81. Here, the thickness of the sheet-like deposits 81 can be, for example, in the range of 20 nm to 100 nm. More preferably, the thickness of the sheet-like deposits 81 is, for example, in the range of 20 nm to 50 nm. The roughened copper metal film 80 has a structure in which the sheet-like deposits 81 are stacked in multiple layers. The roughened copper metal film 80 has a three-dimensional nanostructure in which fine nano-sized sheet-like deposits 81 are folded in multiple layers in random directions. Such a roughened copper metal film 80 is formed in a structure in which the sheet-like deposits 81 are densely folded over the entire thickness of the roughened copper metal film 80, with multiple voids 82 formed therein. That is, the roughened copper metal film 80 has a structure in which numerous fine voids 82 are provided inside throughout the entire thickness direction. In the roughened copper metal film 80, for example, the density of the precipitates 81 varies in the thickness direction. In other words, in the roughened copper metal film 80, for example, the porosity varies in the thickness direction. For example, in the roughened copper metal film 80, the density of the precipitates 81 increases toward the first opposing surface 31 in the thickness direction, that is, the porosity decreases toward the first opposing surface 31. The porosity of the entire roughened copper metal film 80 can be, for example, in the range of 8% to 20%.

[0041] Thus, the roughened copper metal film 80 has a structure in which numerous precipitates 81 intersect and overlap, resulting in a roughened surface structure with concaves and convexes on the surface and numerous voids 82 in the thickness direction. The roughened surface structure of the roughened copper metal film 80 differs from roughened surface structures formed by general roughening treatments, such as chemical roughening treatments or physical processing. Examples of general roughening treatments include blackening, etching, and blasting. More specifically, a roughened surface structure formed by general roughening treatments on the first connection terminal 30 has concaves and convexes formed only on the surface of the first connection terminal 30. This roughened surface structure has a high density of copper precipitates throughout the thickness direction and width direction (i.e., the direction perpendicular to the thickness direction). This roughened surface structure does not have the structure in which precipitates 81 intersect and overlap as shown in FIG. 3 , and does not have voids 82 in the thickness direction or within the metal film. The rough surface structure formed by such a general roughening treatment does not have a structure in which the porosity varies in the thickness direction.

[0042] The roughened copper metal film 80 is bonded to, for example, the first opposing surface 31 of the first connection terminal 30. Here, no intermetallic compound is formed at the interface (bonding interface) between the first connection terminal 30 and the roughened copper metal film 80. That is, the first connection terminal 30 made of copper and the roughened copper metal film 80 made of copper are directly bonded to each other without any other member made of a material other than copper. The roughened copper metal film 80 is integrated with the first connection terminal 30. In each drawing, the first connection terminal 30 and the roughened copper metal film 80 are distinguished from each other by solid lines to make them easier to understand. In reality, the interface between the first connection terminal 30 and the roughened copper metal film 80 may disappear, and the boundary may not be clear.

[0043] (Structure of solder layer 90) The solder layer 90 is formed, for example, so as to cover the entire second opposing surface 51 of the second connection terminal 50. The solder layer 90 is provided, for example, so as to face the roughened copper metal film 80. The solder layer 90 is formed, for example, so as to protrude from the second opposing surface 51 toward the roughened copper metal film 80.

[0044] The solder layer 90 can be made of, for example, lead (Pb)-free solder. The solder layer 90 can be made of, for example, lead-free solder containing a relatively large amount of tin (Sn). The solder layer 90 can be made of, for example, tin (Sn)-silver (Ag)-based, Sn-Cu-based, or Sn-Ag-Cu-based lead-free solder.

[0045] The bonding member 60 is formed by, for example, integrating a roughened copper metal film 80 and a solder layer 90 by a reflow process. The intermetallic compound layer 70 shown in Fig. 2 is formed by a reaction between a metal (e.g., Cu) constituting the roughened copper metal film 80 and a metal (e.g., Sn) constituting the solder layer 90 that has entered numerous voids 82 in the roughened copper metal film 80. Here, the first intermetallic compound layer 71 and the second intermetallic compound layer 72 shown in Fig. 2 have, for example, a higher melting point than the solder layer 90.

[0046] As shown in FIG. 2 , the joining member 60 of this example has a roughened copper metal film 80. In other words, in the joining member 60 of this example, a portion of the roughened copper metal film 80 does not form an intermetallic compound layer 70, and remains as it is in a state of having sheet-like deposits 81 made of copper. For example, the side surface of the joining member 60 has a structure in which the sheet-like deposits 81 intersect and overlap. For example, the portion of the side surface of the joining member 60 on the first opposing surface 31 side (the lower side in the figure) is formed in a structure in which the sheet-like deposits 81 intersect and overlap. In other words, the portion of the side surface of the joining member 60 on the first opposing surface 31 side is composed of the roughened copper metal film 80. This roughened copper metal film 80 is made of, for example, simple Cu.

[0047] The bonding member 60 does not protrude outward beyond the side surface of the first connection terminal 30, for example. That is, the solder layer 90 (see FIG. 3 ) and the like of the bonding member 60 do not protrude outward beyond the side surface of the first connection terminal 30 in the planar direction (left-right direction in the figure). Here, the planar direction is, for example, a direction perpendicular to the thickness direction of the roughened copper metal film 80 in a cross-sectional view. The bonding member 60 does not protrude outward beyond the side surface of the second connection terminal 50, for example. The first connection terminal 30 and the second connection terminal 50 are vertically bonded by this bonding member 60.

[0048] The first connection terminal 30, the joining member 60, and the second connection terminal 50 described above constitute a connection structure. (Structure of external connection terminal 100) As shown in FIG. 1, the external connection terminals 100 are formed on external connection pads P1 of the wiring substrate 20. The external connection terminals 100 are connection terminals that are electrically connected to pads provided on a mounting substrate such as a motherboard (not shown). For example, solder balls or lead pins can be used as the external connection terminals 100. In this embodiment, solder balls are used as the external connection terminals 100.

[0049] (Method of manufacturing the semiconductor device 10) Next, a method for manufacturing the semiconductor device 10 will be described with reference to Figures 4 to 7. Here, a method for manufacturing the connection structure will be described in detail.

[0050] First, as shown in FIG. 4, a wiring substrate 20 is prepared, in which a wiring layer 22 and a solder resist layer 23 are formed on the lower surface of a substrate main body 21, and a wiring layer 24, an insulating layer 25, and a wiring layer 26 are formed on the upper surface of the substrate main body 21. This wiring substrate 20 can be manufactured by a known manufacturing method, and detailed description thereof will be omitted here. The wiring layer 26 having the via wiring 26V and the first connection terminal 30 can be formed, for example, by a semi-additive method. Specifically, first, a seed layer (not shown) is formed to cover the inner surface of the opening 25X and the upper surface of the wiring layer 24 and the upper surface of the insulating layer 25 exposed at the bottom of the opening 25X. Then, a resist pattern (not shown) having openings corresponding to the shape of the first connection terminal 30 is formed on the seed layer. Thereafter, the via wiring 26V and the first connection terminal 30 are formed by electrolytic copper plating using the resist pattern as a plating mask.

[0051] Next, a roughened copper metal film 80 is formed on the first opposing surface 31 of the first connection terminal 30. The roughened copper metal film 80 can be formed by an electrolytic copper plating method. For example, the roughened copper metal film 80 can be formed by an electrolytic copper plating method using an electrolytic copper plating bath containing a roughening agent (additive) as the plating bath and using the first connection terminal 30 and the like as a plating power supply layer. In the electrolytic copper plating method of this step, for example, a resist pattern (not shown) used in forming the wiring layer 26 can be used as a plating mask. Furthermore, for example, a polymer compound can be used as the roughening agent added to the electrolytic copper plating bath. Here, by adjusting the composition, current density, amount of current, etc. of the plating bath used in the electrolytic copper plating method, the roughened copper metal film 80 can be formed into a desired roughened surface structure, i.e., a structure in which copper deposits 81 (see FIG. 3) intersect and overlap. In particular, by adjusting the concentration of the roughening agent (additive), current density, amount of current, bath temperature of the plating bath, etc. in the electrolytic copper plating method, the shape and density of the deposit 81 (see Figure 3) in the roughened copper metal film 80 can be controlled.

[0052] In the step shown in FIG. 4, a semiconductor element 40 having second connection terminals 50 formed on the circuit formation surface and solder layers 90 formed on the lower surfaces of the second connection terminals 50 is prepared. 5, the semiconductor element 40 having the second connection terminals 50 and the solder layer 90 is placed above the wiring substrate 20. At this time, the wiring substrate 20 and the semiconductor element 40 are placed so that the first connection terminals 30 and the second connection terminals 50 face each other. Then, the solder layer 90 is superimposed on the roughened copper metal film 80.

[0053] Next, in the process shown in FIG. 6 , the roughened copper metal film 80 and the solder layer 90 are bonded together by a reflow process. Specifically, after the solder layer 90 is superimposed on the roughened copper metal film 80, a reflow process is performed to melt the solder layer 90 and bond the solder layer 90 to the roughened copper metal film 80. In the reflow process, heating is performed at a temperature higher than the melting point of the solder layer 90. In the reflow process, the molten solder layer 90 penetrates into the numerous voids 82 in the roughened copper metal film 80. At this time, the molten solder layer 90 penetrates into the interior of the roughened copper metal film 80 through the voids 82 in the roughened copper metal film 80, thereby preventing the molten solder layer 90 from spreading in the planar direction. In other words, the molten solder layer 90 spreads in the thickness direction of the roughened copper metal film 80 through the voids 82 in the roughened copper metal film 80, preventing the solder layer 90 from spreading in the planar direction perpendicular to the thickness direction. Then, the metal (here, Sn) constituting the solder layer 90 that has entered the voids 82 of the roughened copper metal film 80 reacts with the metal (here, Cu) constituting the roughened copper metal film 80 to form an intermetallic compound. Specifically, as shown in FIG. 7 , a first intermetallic compound layer 71 made of a Cu6Sn5 intermetallic compound is formed, extending from the second connection terminal 50 to the first connection terminal 30. Also, a second intermetallic compound layer 72 made of a Cu3Sn intermetallic compound is formed and laminated on the outer edge portion of the lower surface of the first intermetallic compound layer 71. In this example, a portion of the roughened copper metal film 80 remains in the state of the roughened copper metal film 80 without forming an intermetallic compound. As a result, a bonding member 60 is formed, which includes the intermetallic compound layer 70 having a structure in which the first intermetallic compound layer 71 and the second intermetallic compound layer 72 are laminated, and the roughened copper metal film 80. The first connection terminal 30 and the second connection terminal 50 are electrically connected via the bonding member 60. This allows the second connection terminal 50 of the semiconductor element 40 to be flip-chip bonded onto the first connection terminal 30 of the wiring substrate 20.

[0054] 6, i.e., the reflow process, heating is performed at a temperature higher than the melting point of the solder layer 90, for example, until all of the Sn in the solder layer 90 forms an intermetallic compound. For example, in the reflow process, the heating is performed until all of the Sn in the solder layer 90 reacts with the Cu in the roughened copper metal film 80 to form an intermetallic compound of Cu6Sn5 or Cu3Sn. For example, in the reflow process, the heating is performed until all of the molten solder layer 90 forms an intermetallic compound.

[0055] Through the steps described above, the semiconductor element 40 can be mounted on the wiring substrate 20. After that, the external connection terminals 100 shown in Fig. 1 are formed on the external connection pads P1 shown in Fig. 5. In this way, the semiconductor device 10 shown in Fig. 1 can be manufactured.

[0056] Next, the effects of this embodiment will be described. (1-1) A roughened copper metal film 80 is formed on the first opposing surface 31 of the first connection terminal 30, and a solder layer 90 is formed on the second opposing surface 51 of the second connection terminal 50. The roughened copper metal film 80 and the solder layer 90 are then joined to form a joining member 60. During a reflow process for joining the roughened copper metal film 80 and the solder layer 90, the molten solder layer 90 penetrates into the voids 82 in the roughened copper metal film 80. At this time, the molten solder layer 90 spreads in the thickness direction of the roughened copper metal film 80 through the voids 82 in the roughened copper metal film 80, thereby preventing the solder layer 90 from spreading in a planar direction perpendicular to the thickness direction. This prevents the joining member 60 joining the first connection terminal 30 and the second connection terminal 50 from spreading in the planar direction. As a result, even if the pitch of the first connection terminals 30 becomes narrower, it is possible to prevent adjacent bonding members 60 from shorting out, and to preferably prevent adjacent first connection terminals 30 from shorting out. In other words, the adjacent first connection terminals 30 can be designed to have a narrow pitch.

[0057] (1-2) The joining member 60 has an intermetallic compound layer 70 formed of a roughened copper metal film 80 and a solder layer 90 that has entered voids 82 in the roughened copper metal film 80. The intermetallic compound layer 70 has a higher melting point than the solder layer 90. Therefore, even when the joining member 60 is exposed to a high-temperature environment, the joining member 60 can be suitably prevented from remelting.

[0058] (1-3) In the reflow process for joining the roughened copper metal film 80 and the solder layer 90, heating is performed at a temperature higher than the melting point of the solder layer 90 until the entire molten solder layer 90 forms an intermetallic compound. This makes it possible to more effectively prevent the joining member 60 from remelting.

[0059] (1-4) The intermetallic compound layer 70 has a portion that extends over the entire thickness direction of the joining member 60. That is, a portion of the intermetallic compound layer 70 extends in the thickness direction of the joining member 60 from the first opposing surface 31 of the first connection terminal 30 to the second opposing surface 51 of the second connection terminal 50. This allows the first connection terminal 30 and the second connection terminal 50 to be joined by a stable intermetallic compound layer 70, thereby improving the connection reliability between the first connection terminal 30 and the second connection terminal 50.

[0060] (1-5) The intermetallic compound layer 70 has a structure in which a first intermetallic compound layer 71 and a second intermetallic compound layer 72 are stacked in the thickness direction of the joining member 60. The first intermetallic compound layer 71 is formed so as to extend over the entire length of the joining member 60 in the thickness direction at the center of the intermetallic compound layer 70 in a plan view. That is, the center of the first intermetallic compound layer 71 in a plan view extends from the first opposing surface 31 of the first connection terminal 30 to the second opposing surface 51 of the second connection terminal 50. This allows the first connection terminal 30 and the second connection terminal 50 to be joined by the single first intermetallic compound layer 71 in a part of the joining member 60. In other words, at the planar center of the joining member 60, only the first intermetallic compound layer 71 exists on the straight line connecting the first opposing surface 31 and the second opposing surface 51, and no interface exists. Therefore, at the planar center of the joining members 60, the physical property values ​​of the joining members 60 are determined only by the physical property values ​​of the first intermetallic compound layer 71. Therefore, at the planar center of the joining members 60, the physical property values ​​such as the resistance value of the joining members 60 can be constant from the first opposing surface 31 to the second opposing surface 51.

[0061] (1-6) The roughened copper metal film 80 has a structure in which sheet-like (thin plate-like) deposits 81 made of copper are folded in various directions, and voids 82 are formed between the sheet-like deposits 81. This roughened copper metal film 80 has a relatively high porosity. Therefore, during the reflow treatment, the molten solder layer 90 easily penetrates into the roughened copper metal film 80 through the voids 82. This allows the amount of solder in the solder layer 90 to be reduced.

[0062] (Second embodiment) The second embodiment will be described below with reference to Figures 8 to 10. In this embodiment, the method of manufacturing a semiconductor device differs from that of the first embodiment. The following description will focus on the differences from the first embodiment. The same components as those shown in Figures 1 to 7 above are designated by the same reference numerals, and detailed description of each element will be omitted.

[0063] First, in the step shown in Fig. 8, a surface-roughened copper metal film 85 is formed on the first opposing surface 31 of the first connection terminal 30. The surface-roughened copper metal film 85 has a different roughness structure from the surface-roughened copper metal film 80 shown in Fig. 3. The structure of the surface-roughened copper metal film 85 will be described in detail below.

[0064] The roughened copper metal film 85 is formed, for example, so as to cover the entire first opposing surface 31. The roughened copper metal film 85 is directly bonded to the first opposing surface 31. The roughened copper metal film 85 is integrated with the first connection terminal 30. In each drawing, the first connection terminal 30 and the roughened copper metal film 85 are distinguished from each other by solid lines to make them easier to understand. In reality, the interface between the first connection terminal 30 and the roughened copper metal film 85 may disappear, and the boundary may not be clear. The thickness (film thickness) of the roughened copper metal film 85 may be, for example, in the range of 0.5 μm to 2 μm.

[0065] The surface (top and side surfaces, or only the top surface) of the roughened copper metal film 85 has a finely uneven structure. The roughened copper metal film 85 has a structure in which granular deposits 86 made of copper, which is the plating metal, intersect and overlap on the first opposing surface 31 of the first connection terminal 30. The roughened copper metal film 85 has a structure in which voids 87 are formed between the granular deposits 86. In other words, the roughened copper metal film 85 has a structure in which a large number of voids 87 are formed inside (a porous structure). The roughened copper metal film 85 is a plating film formed by an electrolytic copper plating method. The roughened copper metal film 85 is, for example, a metal film made of a plating film of only copper.

[0066] The granular precipitates 86 are formed, for example, in a spherical shape. Here, the particle size of the granular precipitates 86 can be, for example, in the range of 20 nm to 100 nm. More preferably, the particle size of the granular precipitates 86 is, for example, in the range of 20 nm to 50 nm. The roughened copper metal film 85 has a structure in which the granular precipitates 86 are stacked in multiple layers. The roughened copper metal film 85 has a three-dimensional nanostructure in which fine nano-sized granular precipitates 86 are randomly oriented and folded into multiple layers. Such a roughened copper metal film 85 has a structure in which the granular precipitates 86 are densely folded over the entire thickness of the roughened copper metal film 85, with multiple voids 87 provided therein. That is, the roughened copper metal film 85 has a structure in which multiple fine voids 87 are provided therein throughout the entire thickness. In the roughened copper metal film 85, for example, the density of the precipitates 86 varies in the thickness direction. For example, in the roughened copper metal film 85, the density of the precipitates 86 increases in the thickness direction toward the first opposing surface 31. The porosity of the entire roughened copper metal film 85 can be set to, for example, in the range of 10% to 25%.

[0067] In this way, the roughened copper metal film 85 has a structure in which numerous granular precipitates 86 intersect and overlap, resulting in an uneven surface and a rough surface structure with numerous voids 87 in the thickness direction.

[0068] The surface-roughened copper metal film 85 having the structure described above can be formed by an electrolytic copper plating method using an electrolytic copper plating bath containing a polymer compound as a surface-roughening agent (additive) as the plating bath and using the first connection terminal 30 and the like as a plating power supply layer, as in the first embodiment. Here, by adjusting the composition, current density, amount of current, and the like of the plating bath used in the electrolytic copper plating method, the surface-roughened copper metal film 85 can be formed into a desired roughened structure, i.e., a structure in which copper deposits 86 (see FIG. 8 ) intersect and overlap. In particular, by adjusting the concentration of the surface-roughening agent (additive), current density, amount of current, bath temperature, and the like in the electrolytic copper plating method, the shape and density of the deposits 86 in the surface-roughened copper metal film 85 can be controlled. Note that the composition of the plating bath and the electrodeposition conditions used in the electrolytic copper plating method differ from those in the first embodiment.

[0069] In the step shown in FIG. 8, a semiconductor element 40 having second connection terminals 50 with solder layers 90 formed on the lower surfaces thereof is prepared. 9, the roughened copper metal film 85 and the solder layer 90 are joined to form a joining member 65 (see FIG. 10) that joins the first connection terminal 30 and the second connection terminal 50. Specifically, after the solder layer 90 is superimposed on the roughened copper metal film 85, a reflow process is performed to melt the solder layer 90 and join the solder layer 90 and the roughened copper metal film 85. The reflow process involves heating at a temperature higher than the melting point of the solder layer 90. The reflow process causes the molten solder layer 90 to penetrate into the numerous voids 87 in the roughened copper metal film 85. At this time, the molten solder layer 90 penetrates into the interior of the roughened copper metal film 85 through the voids 87 in the roughened copper metal film 85, thereby preventing the molten solder layer 90 from spreading in the planar direction. That is, the molten solder layer 90 spreads in the thickness direction of the roughened copper metal film 85 through the voids 87 in the roughened copper metal film 85, thereby preventing the solder layer 90 from spreading in a planar direction perpendicular to the thickness direction. Then, the metal (here, Sn) constituting the solder layer 90 that has entered the voids 87 in the roughened copper metal film 85 reacts with the metal (here, Cu) constituting the roughened copper metal film 85 to form an intermetallic compound.

[0070] Specifically, as shown in FIG. 10 , a first intermetallic compound layer 76 is formed on the second connection terminal 50 side, and a second intermetallic compound layer 77 is formed on the first connection terminal 30 side. The first intermetallic compound layer 76 and the second intermetallic compound layer 77 are stacked to form an intermetallic compound layer 75. The first intermetallic compound layer 76 is made of, for example, an intermetallic compound that is richer in Sn than the second intermetallic compound layer 77. The first intermetallic compound layer 76 is made of, for example, a Cu6Sn5 intermetallic compound. The second intermetallic compound layer 77 is made of, for example, a Cu3Sn intermetallic compound. In this example, a portion of the roughened copper metal film 85 remains as the roughened copper metal film 85 without forming an intermetallic compound. This results in the formation of a bonding member 65 having the intermetallic compound layer 75 and the roughened copper metal film 85. The structure of the joining member 65 will be described in detail below.

[0071] The first intermetallic compound layer 76 is formed, for example, to extend from the second opposing surface 51 toward the first opposing surface 31. The first intermetallic compound layer 76 of the present example is formed to extend from the second opposing surface 51 to partway in the thickness direction of the joining member 65. In other words, the first intermetallic compound layer 76 of the present example does not extend to the first opposing surface 31. The first intermetallic compound layer 76 is formed, for example, to cover the entire surface of the second opposing surface 51. The first intermetallic compound layer 76 is formed, for example, to become thinner in the thickness direction of the joining member 65 as it approaches the first opposing surface 31 from the second opposing surface 51. The lower surface of the first intermetallic compound layer 76 is formed, for example, as a curved surface curved in an arc shape. The lower surface of the first intermetallic compound layer 76 is formed as a curved surface that curves toward the first opposing surface 31 as it approaches the plane center from the outer edge of the joining member 65.

[0072] The second intermetallic compound layer 77 is formed, for example, so as to be laminated on the lower surface of the first intermetallic compound layer 76. The second intermetallic compound layer 77 is formed, for example, so as to cover the entire lower surface of the first intermetallic compound layer 76. The second intermetallic compound layer 77 of the present example does not extend to the first opposing surface 31. In other words, the second intermetallic compound layer 77 of the present example does not cover the first opposing surface 31. The second intermetallic compound layer 77 is formed, for example, so as to become thinner in the thickness direction of the joining member 65 from the first intermetallic compound layer 76 toward the first opposing surface 31. The lower surface of the second intermetallic compound layer 77 is formed, for example, as a curved surface curved in an arc shape. The lower surface of the second intermetallic compound layer 77 is formed as a curved surface that curves toward the first opposing surface 31 as it approaches the center of the plane from the outer edge of the joining member 65. The volume of the second intermetallic compound layer 77 is, for example, smaller than the volume of the first intermetallic compound layer 76.

[0073] The joining members 65 have, for example, a roughened copper metal film 85. In other words, in the joining members 65, a portion of the roughened copper metal film 85 does not form an intermetallic compound and remains as it is, with granular precipitates 86 made of copper. For example, the side surfaces of the joining members 65 have a structure in which the granular precipitates 86 intersect and overlap. For example, a portion of the side surfaces of the joining members 65 on the first opposing surface 31 side (lower side in the figure) is formed with a structure in which the granular precipitates 86 intersect and overlap. That is, a portion of the side surfaces of the joining members 65 on the first opposing surface 31 side is formed with the roughened copper metal film 85. This roughened copper metal film 85 is made of, for example, simple Cu. The roughened copper metal film 85 is provided, for example, closer to the first opposing surface 31 than the intermetallic compound layer 75. The roughened copper metal film 85 is formed, for example, to cover the lower surface of the second intermetallic compound layer 77. The roughened copper metal film 85 is formed, for example, so as to cover the entire lower surface of the second intermetallic compound layer 77. The roughened copper metal film 85 is formed, for example, so as to cover the entire first opposing surface 31.

[0074] The bonding member 65 does not protrude outward beyond the side surface of the first connection terminal 30, for example. That is, the solder layer 90 (see FIG. 9 ) and the like of the bonding member 65 do not protrude outward beyond the side surface of the first connection terminal 30 in the planar direction (left-right direction in the figure). The bonding member 65 does not protrude outward beyond the side surface of the second connection terminal 50, for example. The first connection terminal 30 and the second connection terminal 50 are vertically bonded together by this bonding member 65. This electrically connects the first connection terminal 30 and the second connection terminal 50 via the bonding member 65. The semiconductor element 40 can be mounted on the wiring board 20 through the steps described above.

[0075] In this embodiment, the first connection terminal 30, the joining member 65, and the second connection terminal 50 form a connection structure. According to the present embodiment described above, in addition to the effects (1-1) to (1-3) of the first embodiment, the following effects can be achieved.

[0076] (2-1) The first intermetallic compound layer 76 is formed to overlap the entire second intermetallic compound layer 77 in a planar view. According to this configuration, the first intermetallic compound layer 76 and the second intermetallic compound layer 77 are formed in a layered manner across the entire planar direction of the intermetallic compound layer 75. When the first intermetallic compound layer 76 and the second intermetallic compound layer 77 are layered in this manner, after the joining member 65 is formed, Cu diffuses into the first intermetallic compound layer 76 made of Cu6Sn5, making it easier for a portion of the first intermetallic compound layer 76 to change into a Cu3Sn intermetallic compound. In this case, the region of the second intermetallic compound layer 77 made of Cu3Sn becomes larger. This allows the region of the second intermetallic compound layer 77 made of Cu3Sn, which has superior physical properties such as resistivity, melting point, Young's modulus, tensile strength, and thermal conductivity to Cu6Sn5, to be expanded, thereby improving the physical properties of the joining member 65.

[0077] (Third embodiment) The third embodiment will be described below with reference to Figures 11 to 13. The semiconductor device of this embodiment differs from the first and second embodiments in the configuration of the connection structure. The following description will focus on the differences from the first embodiment. The same components as those shown in Figures 1 to 10 above are designated by the same reference numerals, and detailed description of each element will be omitted.

[0078] As shown in FIG. 11 , the wiring board 20 of this embodiment has a bonding member 60 formed on the board body 21. The semiconductor element 40 of this embodiment has a second connection terminal 50 formed on the circuit formation surface (here, the lower surface) of the semiconductor element 40. The second connection terminal 50 is bonded to the bonding member 60. In the semiconductor device 10 of this embodiment, the semiconductor element 40 is mounted on the wiring board 20 by bonding the second connection terminal 50 to the bonding member 60. In other words, in the semiconductor device 10 of this embodiment, the bonding member 60 functions as a first connection terminal that is connected to the semiconductor element 40. That is, in the semiconductor device 10 of this embodiment, the entire first connection terminal is formed by the bonding member 60.

[0079] (Structure of Joining Member 60) The bonding members 60 are formed on the upper surface of the substrate body 21. In the wiring board 20 of this embodiment, a plurality of bonding members 60 are formed on the upper surface of the substrate body 21. Each bonding member 60 is provided partially on a part of the upper surface of the substrate body 21. The bonding members 60 are electrically connected to the wiring layer 22, for example, via a wiring layer or a through electrode (not shown) in the substrate body 21. The thickness (film thickness) of the bonding members 60 can be, for example, in the range of 1 μm to 20 μm.

[0080] As shown in FIG. 12 , the bonding member 60 has an intermetallic compound layer 70. For example, most of the bonding member 60 is composed of the intermetallic compound layer 70. In the bonding member 60 of this example, the intermetallic compound layer 70 is composed of a portion other than the outer edge portion on the upper surface side of the substrate body 21. The intermetallic compound layer 70 has, for example, a portion extending over the entire thickness direction of the bonding member 60. In other words, a portion of the intermetallic compound layer 70 extends from the second opposing surface 51 to the upper surface of the substrate body 21 in the thickness direction of the bonding member 60. The intermetallic compound layer 70 of this example extends over the entire thickness direction of the bonding member 60 in the center of the bonding member 60 in a plan view.

[0081] The intermetallic compound layer 70 has a structure in which, for example, a first intermetallic compound layer 71 and a second intermetallic compound layer 72 different from the first intermetallic compound layer 71 are stacked in the thickness direction of the joining member 60. The first intermetallic compound layer 71 is made of, for example, a Cu6Sn5 intermetallic compound. The second intermetallic compound layer 72 is made of, for example, a Cu3Sn intermetallic compound. The first intermetallic compound layer 71 and the second intermetallic compound layer 72 have the same structures as the first intermetallic compound layer 71 and the second intermetallic compound layer 72 shown in FIG. 2.

[0082] 13, the bonding member 60 is formed by a roughened copper metal film 80 formed on the upper surface of the substrate body 21 and a solder layer 90 formed on the second opposing surface 51 of the second connection terminal 50. Here, Fig. 13 shows a cross-sectional structure of a portion of the semiconductor device 10 in a state before the semiconductor element 40 is bonded to the wiring substrate 20. The structures of the roughened copper metal film 80 and the solder layer 90 will be described below.

[0083] (Structure of the roughened copper metal film 80) The roughened copper metal film 80 is formed on the upper surface of the substrate body 21. In the wiring board 20 of this embodiment, a plurality of roughened copper metal films 80 are formed on the upper surface of the substrate body 21. Each roughened copper metal film 80 is provided partially on a part of the upper surface of the substrate body 21. The roughened copper metal film 80 is electrically connected to the wiring layer 22 shown in FIG. 11 via, for example, a wiring layer or a through electrode (not shown) in the substrate body 21. The thickness (film thickness) of the roughened copper metal film 80 can be, for example, in the range of 1 μm to 20 μm.

[0084] The roughened copper metal film 80 is a plating film whose surface (top and side surfaces, or only the top surface) is roughened. The surface of the roughened copper metal film 80 has a fine uneven structure. The roughened copper metal film 80 has a structure in which sheet-like deposits 81 made of copper, which is the plating metal, intersect and overlap on the top surface of the substrate body 21. The roughened copper metal film 80 has a structure in which voids 82 are formed between the sheet-like deposits 81. The roughened copper metal film 80 is a plating film formed by an electrolytic copper plating method. The roughened copper metal film 80 is, for example, a metal film made of a plating film of only copper.

[0085] The roughened copper metal film 80 is formed, for example, on a seed layer (not shown) formed on the upper surface of the substrate body 21. The roughened copper metal film 80 is, for example, integrated with the seed layer. The seed layer may be made of, for example, copper or a copper alloy.

[0086] (Structure of solder layer 90) The solder layer 90 is formed, for example, so as to cover the entire second opposing surface 51 of the second connection terminal 50. The solder layer 90 is provided, for example, so as to face the roughened copper metal film 80. The solder layer 90 is formed, for example, so as to protrude from the second opposing surface 51 toward the roughened copper metal film 80.

[0087] The joining member 60 is formed by, for example, integrating a roughened copper metal film 80 and a solder layer 90 by a reflow process. The intermetallic compound layer 70 shown in FIG. 12 is formed by a reaction between a metal (e.g., Cu) constituting the roughened copper metal film 80 and a metal (e.g., Sn) constituting the solder layer 90 that has entered numerous voids 82 in the roughened copper metal film 80. As shown in FIG. 12, the joining member 60 has, for example, a roughened copper metal film 80. In other words, in the joining member 60, a portion of the roughened copper metal film 80 does not form the intermetallic compound layer 70 but remains as it is, containing a sheet-like deposit 81 made of copper. For example, a portion of the side surface of the joining member 60 facing the substrate body 21 is formed of the roughened copper metal film 80. This roughened copper metal film 80 is made of, for example, simple Cu.

[0088] The bonding member 60 does not protrude outward beyond the side surface of the second connection terminal 50. That is, the bonding member 60 has a solder layer 90 (see FIG. 13) and the like that do not protrude outward beyond the side surface of the second connection terminal 50 in the planar direction (the left-right direction in the figure).

[0089] The second connection terminal 50 and the joining member 60 described above constitute a connection structure. (Method of manufacturing the semiconductor device 10) Next, a description will be given of a method for manufacturing the semiconductor device 10. Here, the steps of forming the roughened copper metal film 80 and the bonding members 60 will be described in detail.

[0090] As shown in Fig. 13, the roughened copper metal film 80 is formed on the upper surface of the substrate body 21. More specifically, first, a seed layer (not shown) is formed to cover the upper surface of the substrate body 21. The seed layer can be formed by, for example, electroless copper plating or sputtering. Next, a resist pattern (not shown) having openings corresponding to the shape of the roughened copper metal film 80 is formed on the seed layer. Next, the roughened copper metal film 80 is formed in the openings of the resist pattern by electrolytic copper plating using the resist pattern as a plating mask and the seed layer as a plating power supply layer.

[0091] Also, as shown in FIG. 13, a semiconductor element 40 having second connection terminals 50 with solder layers 90 formed on the undersides thereof is prepared. Next, the roughened copper metal film 80 and the solder layer 90 are bonded by a reflow process. Specifically, after the solder layer 90 is superimposed on the roughened copper metal film 80, a reflow process is performed to melt the solder layer 90 and bond the solder layer 90 and the roughened copper metal film 80. This forms the bonding member 60 shown in FIG. 12 , that is, the bonding member 60 having the intermetallic compound layer 70 and the roughened copper metal film 80.

[0092] According to the present embodiment described above, it is possible to achieve the same effects as the first embodiment. (Other embodiments) The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0093] In the first and second embodiments, the roughened copper metal films 80, 85 are formed to cover only the first opposing surface 31 of the surface of the first connection terminal 30, but the present invention is not limited to this.

[0094] 14, for example, a surface-roughened copper metal film 80 may be formed so as to cover the side surface and first opposing surface 31 of the first connection terminal 30. Similarly, a surface-roughened copper metal film 85 (see FIG. 8) may be formed so as to cover the side surface and first opposing surface 31 of the first connection terminal 30.

[0095] The structure of the joining member 60 in the first and third embodiments can be modified as needed. For example, the bonding member 60 may be formed only from the intermetallic compound layer 70. In this case, the entire surface-roughened copper metal film 80 is formed on the intermetallic compound layer 70, for example, in a reflow treatment.

[0096] For example, the intermetallic compound layer 70 does not have to have a portion that extends over the entire thickness direction of the joining member 60. In this case, the intermetallic compound layer 70 is formed, for example, to extend from the second opposing surface 51 to partway in the thickness direction of the joining member 60. Then, a surface-roughened copper metal film 80 is provided between the intermetallic compound layer 70 and the first opposing surface 31 or the upper surface of the substrate body 21.

[0097] For example, the volume of the first intermetallic compound layer 71 may be equal to the volume of the second intermetallic compound layer 72, or may be smaller than the volume of the second intermetallic compound layer 72. The structure of the joining member 65 in the second embodiment can be modified as needed.

[0098] For example, the intermetallic compound layer 75 may have a portion extending over the entire thickness direction of the bonding member 65. In this case, for example, at least a portion of the second intermetallic compound layer 77 is formed to cover the first opposing surface 31.

[0099] For example, the bonding member 65 may be formed only from the intermetallic compound layer 75. In this case, the entire surface-roughened copper metal film 85 is formed on the intermetallic compound layer 75, for example, in a reflow process.

[0100] For example, the volume of the first intermetallic compound layer 76 may be equal to the volume of the second intermetallic compound layer 77 or may be smaller than the volume of the second intermetallic compound layer 77. In the first and second embodiments, the roughened copper metal films 80, 85 are directly bonded to the first opposing surface 31 of the first connection terminal 30, but this is not limiting. For example, a surface treatment layer may be formed to cover the first opposing surface 31 of the first connection terminal 30, and the roughened copper metal films 80, 85 may be formed on the surface treatment layer. Note that the surface treatment layer may be, for example, a metal layer such as an Au layer, a Ni layer / Au layer, or a Ni layer / Pd layer / Au layer.

[0101] In the first and second embodiments, the roughened copper metal films 80, 85 are formed on the first connection terminal 30 of the wiring layer 26, but this is not limiting. For example, the entire wiring layer 26 may be formed of the roughened copper metal films 80, 85. That is, the via wiring 26V and the first connection terminal 30 may be formed of the roughened copper metal films 80, 85. In this case, the roughened copper metal films 80, 85 are formed on the upper surface of the wiring layer 24 exposed from the opening 25X. That is, the roughened copper metal films 80, 85 in this case are formed on the upper surface of the wiring layer 24 exposed from the opening 25X in a structure in which deposits 81, 86 made of copper, which is the plating metal, intersect and overlap with each other on the upper surface of the wiring layer 24 exposed from the opening 25X.

[0102] In the first and second embodiments, the roughened copper metal films 80, 85 are formed on the first connection terminals 30 of the wiring substrate 20, and the solder layers 90 are formed on the second connection terminals 50 of the semiconductor elements 40, but this is not limiting. For example, the solder layers 90 may be formed on the first connection terminals 30 of the wiring substrate 20, and the roughened copper metal films 80, 85 may be formed on the second connection terminals 50 of the semiconductor elements 40.

[0103] In the third embodiment, the roughened copper metal film 80 is formed on the upper surface of the substrate body 21, and the solder layer 90 is formed on the second connection terminal 50 of the semiconductor element 40. However, this is not limiting. For example, the solder layer 90 may be formed on the upper surface of the substrate body 21, and the roughened copper metal film 80 may be formed on the second connection terminal 50 of the semiconductor element 40.

[0104] The joining member 60 in the third embodiment may be changed to a joining member 65. The surface-roughened copper metal film 80 in the third embodiment may be changed to a surface-roughened copper metal film 85 .

[0105] The roughened copper metal films 80 and 85 in the above embodiments may be changed to roughened metal films made of a metal material other than copper. The structure of the wiring board 20 in each of the above embodiments can be modified as appropriate.

[0106] The structure of the semiconductor element 40 in each of the above embodiments can be modified as appropriate. The first connection terminal 30 in the first and second embodiments is not limited to a metal post.

[0107] The second connection terminal 50 in each of the above embodiments is not limited to a metal post. The first connection terminal 30 in the first and second embodiments may be made of a metal material other than copper.

[0108] The second connection terminal 50 in each of the above embodiments may be made of a metal material other than copper. The external connection terminals 100 in the semiconductor device 10 of each of the above embodiments may be omitted. [Explanation of symbols]

[0109] 10 Semiconductor devices 20 Wiring board 26 wiring layer 30 First connection terminal 31 First opposing surface 40 Semiconductor elements 50 Second connection terminal 51 Second opposing surface 60,65 Joint members 70,75 Intermetallic compound layer 71,76 1st intermetallic compound layer 72,77 Second intermetallic compound layer 80,85 Roughened copper metal film 81,86 Precipitate 82,87 void 90 solder layer

Claims

1. A first connection terminal; a second connection terminal facing the first connection terminal; a joining member that joins the first connection terminal and the second connection terminal, the joining member has an intermetallic compound layer formed by a roughened metal film having a structure in which metal deposits are intertwined and overlapped and having a large number of voids therein, and a solder layer that has entered the voids; The intermetallic compound layer is a connection structure having a structure in which a first intermetallic compound layer and a second intermetallic compound layer different from the first intermetallic compound layer are stacked in the thickness direction of the joining member.

2. The connection structure according to claim 1 , wherein the intermetallic compound layer has a portion extending over the entire thickness of the joining member.

3. the roughened metal film is made of a metal material containing copper, the solder layer is made of a metal material containing tin, The first intermetallic compound layer is Cu ６ Sn ５ and The second intermetallic compound layer is Cu ３ 2. The connection structure according to claim 1, which is made of an intermetallic compound of Sn.

4. the first intermetallic compound layer is formed at a central portion of the intermetallic compound layer in a plan view so as to extend over an entire length in a thickness direction of the joining members, The connection structure according to claim 1 , wherein the second intermetallic compound layer is laminated with the first intermetallic compound layer at an outer edge portion of the intermetallic compound layer in a plan view.

5. The connection structure according to claim 1 , wherein the first intermetallic compound layer is formed so as to overlap the entire second intermetallic compound layer in a plan view.

6. The connection structure according to claim 1 , wherein the side surface of the joining member has a structure in which the sheet-like deposits intersect and overlap each other.

7. The connection structure according to claim 1 , wherein the side surface of the joining member has a structure in which the granular precipitates intersect and overlap each other.

8. a wiring substrate having a first connection terminal; a semiconductor element mounted on the wiring substrate, the semiconductor element having a second connection terminal facing the first connection terminal; a joining member that joins the first connection terminal and the second connection terminal, the joining member has an intermetallic compound layer formed by a roughened metal film having a structure in which metal deposits are intertwined and overlapped and having a large number of voids therein, and a solder layer that has entered the voids; The intermetallic compound layer has a structure in which a first intermetallic compound layer and a second intermetallic compound layer different from the first intermetallic compound layer are stacked in the thickness direction of the joining member.

9. forming a first connection terminal having a first opposing surface; forming a surface-roughened copper metal film having a structure in which copper deposits intersect and overlap on the first opposing surface and having a large number of voids therein by an electrolytic copper plating method; forming a second connection terminal having a solder layer provided on a second opposing surface opposite to the first opposing surface; and joining the roughened copper metal film and the solder layer by a reflow treatment, The roughened copper metal film is formed by an electrolytic copper plating method using an electrolytic copper plating bath containing a polymer compound as a plating bath, In the step of joining the roughened copper metal film and the solder layer, the solder layer melted by the reflow treatment enters into the voids in the roughened copper metal film, and a metal constituting the solder layer reacts with a metal constituting the roughened copper metal film to form an intermetallic compound layer, and a joining member having the intermetallic compound layer and joining the first connection terminal and the second connection terminal is formed; A method for manufacturing a connection structure in which the intermetallic compound layer is formed in a structure in which a first intermetallic compound layer and a second intermetallic compound layer different from the first intermetallic compound layer are stacked in the thickness direction of the joining member.

Images