JP2017050354A - Semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor module capable of facilitating confirmation of bonding to a land on a wiring board of a semiconductor device in a top plan view.SOLUTION: A semiconductor module (100) according to one embodiment, comprises: a wiring board (10) that comprises a land (15a) having a first surface (151) and a second surface (152) higher than the first surface (151); a semiconductor device (20) that comprises an external connection terminal (25) arranged on the second surface (152); and a bonding member (30) arranged over the second surface (152) and the first surface (151) outside the semiconductor device (20), and that bonds between the external connection terminal (25) and the land (15a).SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a semiconductor module.

  For example, Patent Document 1 describes a light emitting device in which an LED lamp is joined to a metal core substrate via solder or the like.

JP 2008-021867 A

  In such a light emitting device, when solder or the like is hidden behind the LED lamp when viewed from above, it is difficult to confirm the bonding between the LED lamp and the metal core substrate.

  Accordingly, an embodiment of the present invention has been made in view of such circumstances, and an object thereof is to provide a semiconductor module that allows easy confirmation of bonding of a semiconductor device to a land portion of a wiring board in a top view. .

  A semiconductor module according to an embodiment of the present invention includes a wiring board including a land portion having a first surface and a second surface higher than the first surface, and an external connection terminal disposed on the second surface. And a bonding member that is disposed over the second surface and the first surface outside the semiconductor device, and that joins the external connection terminal and the land portion. It is characterized by.

  According to the semiconductor module of one embodiment of the present invention, the joining member is disposed to the outside of the semiconductor device, and it is easy to confirm the joining of the semiconductor device to the land portion of the wiring board in a top view.

It is the schematic top view (a) of the semiconductor module which concerns on one embodiment of this invention, and the schematic sectional drawing (b) in the AA cross section. FIG. 2 is a schematic top view (a) of the wiring board shown in FIG. 1, a schematic cross-sectional view (b) taken along the line BB, and schematic cross-sectional views (c) and (d) of the wiring board according to a modification. FIG. 2 is a schematic perspective view (a) of the upper surface side of the semiconductor device shown in FIG. 1 and a schematic perspective view (b) of the lower surface side.

  Hereinafter, embodiments of the invention will be described with reference to the drawings as appropriate. However, the semiconductor module described below is for embodying the technical idea of the present invention, and the present invention is not limited to the following unless otherwise specified. In addition, the size, positional relationship, and the like of members illustrated in the drawings may be exaggerated for clarity of explanation.

<Embodiment 1>
FIG. 1A is a schematic top view of the semiconductor module 100 according to the first embodiment, and FIG. 1B is a schematic cross-sectional view taken along the line AA. 2A is a schematic top view of the wiring board 10 shown in FIG. 1, and FIG. 2B is a schematic cross-sectional view taken along the line BB. 3A and 3B are a schematic perspective view on the upper surface side and a schematic perspective view on the lower surface side of the semiconductor device 20 shown in FIG. 1, respectively.

  In the figure, in a top view of the semiconductor module 100, the first direction is indicated as the x direction, and the second direction orthogonal to the first direction is indicated as the y direction. Also, the direction orthogonal to the x direction and the y direction is shown as the z direction. Here, the first direction can be selected, for example, as a direction parallel to one side forming the outline of the semiconductor device in a top view of the semiconductor module, and in a semiconductor device having a longitudinal direction and a short direction in the top view, the longitudinal direction. Can be selected. Hereinafter, the x direction may be described as the horizontal direction, the y direction as the vertical direction, and the z direction as the height (thickness) direction.

  As shown in FIGS. 1A and 1B, the semiconductor module 100 according to the first embodiment includes a wiring board 10, a semiconductor device 20, and a bonding member 30.

  As shown in FIGS. 2A and 2B, the wiring board 10 includes a land portion 15a. More specifically, the wiring board 10 includes a base body 11 and wirings 15, and the land portion 15 a is a part of the wiring 15 where the external connection terminals 25 of the semiconductor device 20 are joined by the joining member 30. The land portion 15a forms a positive / negative electrode pair. The upper surface of the land portion 15a is formed of an exposed metal surface. Here, the metal includes an alloy. The land portion 15a may be formed by patterning the metal itself constituting the wiring 15 as in the present embodiment, or may be an insulating protection such as a resist or a coverlay provided on the metal constituting the wiring 15. It may be formed by an opening in the film. And the land part 15a has the 1st surface 151 and the 2nd surface 152 whose height is higher than the 1st surface 151, for example, as shown to Fig.2 (a) and (b). That is, the land portion 15a has at least one step, the first surface 151 being a lower step, and the second surface 152 being an upper step. In the present embodiment, both the first surface 151 and the second surface 152 are flat surfaces and are substantially parallel to each other.

  As shown in FIGS. 3A and 3B, the semiconductor device 20 includes an external connection terminal 25. More specifically, the semiconductor device 20 is mainly a surface mount type. The semiconductor device 20 includes a semiconductor element 21 mounted on a package 23 and sealed with a sealing member 27. The package 23 is formed by holding a pair of positive and negative lead electrodes on a container body having a recess on the upper surface for housing the semiconductor element 21. The semiconductor element 21 is mounted on the upper surface of the lead electrode that forms the bottom surface of the recess of the package 23, and is connected to both the lead electrodes by wires. The sealing member 27 is filled in the recess of the package 23. The external connection terminal 25 is constituted by a part of a pair of positive and negative lead electrodes. That is, there is a pair of external connection terminals 25 for each semiconductor device 20. The external connection terminal 25 is the same surface as the lower surface of the container body, and constitutes a lower surface that is a mounting surface of the semiconductor device 20. And as shown in FIG.1 (b), the external connection terminal 25 is arrange | positioned on the 2nd surface 152 of the land part 15a.

  As shown in FIGS. 1A and 1B, the joining member 30 is melted by heat treatment and then solidified to join the external connection terminal 25 and the land portion 15a. The bonding member 30 is disposed over the second surface 152 and the first surface 151 outside the semiconductor device 20. Here, “outside of the semiconductor device 20” mainly refers to the outside of the semiconductor device 20 in the top view of the semiconductor module 100.

  In the semiconductor module 100 having such a configuration, the bonding member 30 is disposed outside the semiconductor device 20 in a top view, and it is easy to confirm the bonding of the semiconductor device 20 to the land portion 15a of the wiring board in the top view. This is because the height of the external connection terminal 25 with respect to the first surface 151 can be increased by the second surface 152 of the land portion 15a, whereby the joining member 30 that joins the external connection terminal 25 and the first surface 151. This is considered to be because the bottom of the side can be easily spread outward from the semiconductor device 20 in a top view.

  In the present embodiment, the land portion 15 a and the external connection terminal 25 are paired, and the same polarity of the land portion 15 a and the external connection terminal 25 is joined by the joining member 30. The bonding member 30 disposed over the second surface 152 and the first surface 151 outside the semiconductor device 20 in the top view may be provided on at least one of the poles, but from the viewpoint of bonding reliability, Preferably at both poles. Hereinafter, only one pole will be described, but the same applies to the other pole.

  In the present embodiment, the first surface 151 is disposed only in the first direction x with respect to the second surface 152, but the first surface 151 is in the second direction y with respect to the second surface 152. May be arranged only in the first direction x or in the second direction y with respect to the second surface 152. Therefore, the “first surface 151 outside the semiconductor device 20” is not limited to the first surface 151 disposed in the first direction x with respect to the second surface 152, but in the second direction with respect to the second surface 152. It may be the first surface 151 arranged at y, or both of them.

  Hereinafter, a preferred embodiment of the semiconductor module 100 will be described in detail.

As shown in FIGS. 1A and 2A, the first surface 151 and the second surface 152 are juxtaposed in the first direction x when viewed from above. The top surface shape of the second surface 152 and the external connection terminal 25 is preferably a rectangular shape having substantially the same width (W _152-1 , W _25-1 ) in the second direction y (FIG. 2A). And FIG. 3 (b)). Thereby, the base of the joining member 30 that joins the external connection terminal 25 and the first surface 151 is likely to spread toward the first surface 151, and the joining member 30 is on the first surface 151 outside the semiconductor device 20 in a top view. It becomes easy to be placed in. In addition, the self-alignment effect of the semiconductor device 20 is easily obtained.

In addition, the width L _{152-1 in} the first direction x of the second surface 152 is preferably equal to or smaller than the width L _{25-1 in} the first direction x of the external connection terminal 25, and is smaller than L _25-1. Preferred (see FIG. 2 (a) and FIG. 3 (b)). As a result, the base of the joining member 30 that joins the external connection terminal 25 and the first surface 151 becomes easier to expand to the first surface 151 side, and the joining member 30 is the first surface 151 outside the semiconductor device 20 in a top view. It will be easier to place on top.

  As shown in FIG. 3B, the external connection terminal 25 is preferably exposed only on the lower surface of the semiconductor device 20. When the external connection terminal is exposed on the side surface of the semiconductor device, the bonding member adheres to the side surface of the semiconductor device and is easily disposed outside the semiconductor device in a top view. On the other hand, when the external connection terminal 25 is exposed only on the lower surface of the semiconductor device 20, the bonding member 30 adheres only to the lower side of the semiconductor device 20 and is difficult to be disposed outside the semiconductor device 20 in a top view. The technical significance of the configuration of the form increases. Note that “external connection terminal 25 is exposed only on the lower surface of semiconductor device 20” refers to, for example, the case where the entire periphery of external connection terminal 25 is surrounded by the container body on the lower surface of semiconductor device 20.

  FIG. 2C is a schematic cross-sectional view of a wiring board 101 according to a modification. As shown in FIG. 2C, the land portion 15 a preferably has an inclined surface 153 between the first surface 151 and the second surface 152. As a result, the base of the joining member 30 that joins the external connection terminal 25 and the first surface 151 becomes easier to expand to the first surface 151 side, and the joining member 30 is the first surface 151 outside the semiconductor device 20 in a top view. It will be easier to place on top. The inclination angle θ of the inclined surface 153 (the inner angle formed by the second surface 152 and the inclined surface 153) is not particularly limited, but from the viewpoint of facilitating disposing the bonding member 30 outside the semiconductor device 20 in a top view. For example, it is 95 ° or more, preferably 100 ° or more, and more preferably 135 ° or more. Further, the inclination angle θ of the inclined surface 153 is, for example, 175 ° or less from the viewpoint of the relationship between the height difference d between the first surface 151 and the second surface 152 and / or the land portion 15a being formed in a small size, 170 degrees or less is preferable and 160 degrees or less is more preferable. The inclined surface 153 includes not only a flat surface but also a curved surface. In the case of a curved surface, the inclination angle θ is considered as a tangential plane.

  The height difference d between the first surface 151 and the second surface 152 is not particularly limited, but is, for example, 0.1 mm or more from the viewpoint of facilitating disposing the bonding member 30 outside the semiconductor device 20 in a top view. 0.15 mm or more is preferable, and 0.2 mm or more is more preferable. Further, the height difference d between the first surface 151 and the second surface 152 is, for example, 0.6 mm or less and preferably 0.5 mm or less from the viewpoint of forming the land portion 15a in a small size within the range where the above-described effects are achieved. 0.4 mm or less is more preferable.

  FIG. 2D is a schematic cross-sectional view of a wiring board 102 according to a modification. As shown in FIG. 2D, the semiconductor module includes a support member 40 that is disposed under the wiring substrate 102 and has a convex portion 45. This wiring board 102 is a flexible wiring board. The first surface 151 and the second surface 152 are preferably provided by bending the wiring board 102 along the convex portion 45. Thus, in order to form the first surface 151 and the second surface 152 in the land portion 15a, it is not necessary to partially change the thickness of the wiring 15 (land portion 15a) itself, for example, a wiring having a substantially constant thickness. 15 (land portion 15a), the first surface 151 and the second surface 152 can be formed on the land portion 15a.

  Hereinafter, each component in the semiconductor module 100 which concerns on one embodiment of this invention is explained in full detail.

(Wiring boards 10, 101, 102)
(Substrate 11)
The base 11 of the wiring board 10 is preferably one having electrical insulation, but even one having electrical conductivity can be electrically insulated from the wiring 15 through an insulating film or the like. Examples of the material of the substrate 11 of the wiring board 10 include ceramics containing aluminum oxide, aluminum nitride or a mixture thereof, metals containing copper, iron, nickel, chromium, aluminum, silver, gold, titanium, or alloys thereof, and epoxy. Examples thereof include resins such as resin, BT resin, and polyimide resin, or fiber reinforced resins thereof (the reinforcing material is glass or the like). The wiring board 10 can be a rigid board or a flexible board depending on the material and thickness of the base 11.
(Wiring 15)
The wiring 15 is formed on at least the upper surface of the substrate 11 and may be formed on the inside, the lower surface, and the side surface of the substrate 11. The wiring 15 preferably has a land portion 15a to which the semiconductor device 20 is bonded, a terminal portion for external connection, a lead-out wiring portion for connecting them, and the like. Examples of the material for the wiring 15 include copper, nickel, palladium, rhodium, tungsten, chromium, titanium, aluminum, silver, gold, and alloys thereof. In particular, copper or a copper alloy is preferable from the viewpoint of heat dissipation. In that case, the surface layer of the wiring 15 is preferably provided with a coating of silver, gold, or an alloy thereof. These wirings 15 can be formed by electrolytic plating, electroless plating, sputtering, vapor deposition, printing, application, sticking, pressure bonding, cofire method, postfire method, or the like.

(Semiconductor device 20)
(Semiconductor element 21)
The semiconductor element 21 may be a light emitting element, a light receiving element, or an electronic element. Examples of the light emitting element include a light emitting diode (LED) chip and a semiconductor laser (LD) chip. A photodiode chip etc. are mentioned as a light receiving element. Examples of the electronic element include a transistor chip, an IC chip, and an LSI chip. As a semiconductor material, nitriding is a material that can emit short-wavelength light that can excite phosphors efficiently, can realize a high-efficiency solar cell, and can realize high-frequency and high-temperature electronic devices. It is preferable to use a physical semiconductor (mainly represented by the general formula In _x Al _y Ga _1-xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1)).
(Package 23)
The package 23 mainly includes a lead electrode that is electrically connected to the semiconductor element 21 and a container body that holds the lead electrode (premold package). The lead electrode can be formed of gold, silver, copper, iron, aluminum, tungsten, cobalt, molybdenum, chromium, titanium, nickel, palladium, or an alloy thereof, phosphor bronze, iron-containing copper, or the like. In addition, a film made of silver, aluminum, rhodium, gold, copper, or an alloy thereof may be provided on the surface layer of the lead electrode. The container body usually has a recess for housing a semiconductor element, but may be flat (in this case, referred to as a substrate body). The container body is a thermoplastic resin such as alicyclic polyamide resin, semi-aromatic polyamide resin, polycyclohexylene dimethylene terephthalate, polycyclohexane terephthalate, or thermosetting epoxy resin, modified epoxy resin, silicone resin, modified silicone resin, etc. And those having a base resin as a base material. In addition, particles or fibers such as silica, titanium oxide, aluminum oxide, zinc oxide, carbon black, glass, calcium silicate (wollastonite), and potassium titanate are mixed in these base materials as fillers or coloring pigments. Can be made. In addition, the container body can be made of ceramics containing aluminum oxide, aluminum nitride, or a mixture thereof. In addition, when the semiconductor element 21 is an electronic element, the package 23 and the sealing member 27 may be integrated (full mold package).
(Sealing member 27)
The sealing member 27 is a member that seals the semiconductor element 21. Examples of the base material of the sealing member 27 include a silicone resin, an epoxy resin, or a modified resin or a hybrid resin thereof. The sealing member 27 may contain a filler and / or a phosphor in the base material. Examples of the filler include silica. Examples of the phosphor include YAG: Ce (cerium-activated yttrium / aluminum / garnet).

(Jointing member 30)
The joining member 30 is a member that joins the land portion 15a of the wiring board and the external connection terminal 25 of the semiconductor device. Examples of the bonding member 30 include various solders and low melting point metal brazing materials. More specific solders include, for example, tin-bismuth, tin-copper, tin-silver, and gold-tin. The joining member 30 may be in the form of a paste containing an organic solvent, a flux and the like before the heat treatment.

(Supporting member 40)
The material of the support member 40 is not particularly limited as long as it is a solid that can support the flexible wiring board, but for example, a metal plate excellent in heat dissipation or a relatively inexpensive resin plate is preferable. Examples of the material for the metal plate include copper, aluminum, and alloys thereof. Examples of the material for the resin plate include acrylic resin, polycarbonate resin, and polyamide resin. The support member 40 may be a housing that houses the semiconductor module 100.

  Examples according to the present invention will be described in detail below. Needless to say, the present invention is not limited to the following examples.

<Example 1>
The semiconductor module of Example 1 is a linear light source module having a structure shown in FIGS. 1A and 1B and used for an edge type backlight unit or the like. In this semiconductor module, 24 semiconductor devices are bonded to each land portion of the wiring board as follows by bonding members at substantially equal intervals.

The wiring board is formed by forming a copper-coated wiring with a gold coating (maximum thickness of 0.4 mm) on a polyimide (flexible) substrate having a width of 160 mm, a length of 1.9 mm, and a thickness of 0.025 mm. The first surface on the negative electrode side of the land portion has a rectangular shape with a width of 0.75 mm and a length of 0.86 mm, and the second surface has a width of 1.56 mm (L _152-1 ) and a length of 0.86 mm (W _{152 -1} ) rectangular shape. The first surface on the positive electrode side of the land portion has a rectangular shape with a width of 0.75 mm and a length of 0.86 mm, and the second surface has a width of 0.54 mm (L _152-2 ) and a length of 0.86 mm (W _{152 -2} ). The height difference (d) between the first surface and the second surface is 0.2 mm on both the negative electrode side and the positive electrode side.

The semiconductor device is an LED capable of emitting white light having a width of 3.0 mm, a length of 1.4 mm, and a thickness of 0.52 mm. The package has a recess for accommodating semiconductor elements on the top surface, and a pair of positive and negative lead electrodes (thickness 0.2 mm) made of a copper alloy with a silver coating is integrally formed with a container body of a cured product of titanium oxide containing epoxy resin Being done. The semiconductor element is an LED chip that emits blue light, and is mounted on the upper surface of the lead electrode on the negative electrode side that constitutes the bottom surface of the recess of the package, and is connected to both the lead electrodes with gold wires. The sealing member is a cured product of a silicone resin containing a YAG: Ce phosphor that emits yellow light, and is filled in a recess of the package. The external connection terminal is constituted by the lower surfaces of a pair of positive and negative lead electrodes, the negative electrode side is 1.56 mm (L _25-1 ) wide, 0.86 mm (W _25-1 ) long, and the positive electrode side is 0.54 mm wide (L _{25- 2} ), a rectangular shape of 0.86 mm (W _25-2 ) in length (the corners are rounded). The external connection terminal is flush with the lower surface of the container body and constitutes the lower surface of the semiconductor device. In addition, the part exposed to the side surface of the package of the lead electrode is a cut surface of the suspension lead part and is not included in the external connection terminal.

  The joining member is tin-3.0 silver-0.5 copper solder. The heat treatment is a reflow method, and the maximum temperature reached is 250 ° C.

  In the semiconductor module according to the first embodiment configured as described above, the bonding member is disposed outside the semiconductor device in a top view as compared with the case where the land portion is configured by one flat surface, and the wiring board of the semiconductor device It is easy to check the connection to the land part from the top view.

  A semiconductor module according to an embodiment of the present invention includes a backlight device for a liquid crystal display, various lighting fixtures, a large display, various display devices such as advertisements and destination guides, a projector device, a digital video camera, a facsimile, a copy It can be used for an image reading apparatus in a machine, a scanner or the like.

10, 101, 102 ... Wiring substrate (11 ... Base, 15 ... Wiring (15a ... Land (151 ... First surface, 152 ... Second surface, 153 ... Inclined surface)))
20 ... Semiconductor device (21 ... Semiconductor element, 23 ... Package, 25 ... External connection terminal, 27 ... Sealing member)
30 ... Joining member 40 ... Supporting member (45 ... Projection)
100: Semiconductor module

Claims (6)

A wiring board comprising a land portion having a first surface and a second surface higher than the first surface;
A semiconductor device comprising an external connection terminal disposed on the second surface;
A bonding member that is disposed over the second surface and the first surface outside the semiconductor device, and bonds the external connection terminal and the land portion;
A semiconductor module comprising:   The semiconductor module according to claim 1, wherein the land portion has an inclined surface between the first surface and the second surface. A support member disposed under the wiring board and having a convex portion;
The wiring board is a flexible wiring board,
The semiconductor module according to claim 1, wherein the first surface and the second surface are provided by bending the wiring board along the convex portion. In top view, the first surface and the second surface are juxtaposed in the first direction,
4. The semiconductor module according to claim 1, wherein the top surface shape of the second surface and the external connection terminal is a rectangular shape having substantially the same width in a second direction orthogonal to the first direction. 5.   The semiconductor module according to claim 4, wherein a width of the second surface in the first direction is equal to or less than a width of the external connection terminal in the first direction.   The semiconductor module according to claim 1, wherein the external connection terminal is exposed only on a lower surface of the semiconductor device.

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