JP2014220302A - Mold package - Google Patents

Abstract

In a mold package in which components are mounted and bonded to a metal land on a substrate via a conductive bonding material such as solder and these are sealed with a mold resin provided on the substrate, Even if Au plating is performed, the speed at which the separation between the land and the mold resin reaches the substrate is made as slow as possible. A land 20 includes a first layer 21 made of metal and a second layer 22 made of metal sequentially stacked from one surface 11 side of a substrate 10, and the first layer 21 is made of a second layer. By making the plane size smaller than the layer 22 of the first layer 21, the end 21a of the first layer 21 is set to a position where the end 22a of the second layer 22 is retracted. Both end portions 21 a and 22 a of both layers 21 and 22 are in contact with the mold resin 50. [Selection] Figure 2

Description

  The present invention relates to a mold package in which components are mounted on a metal land on a substrate via a conductive bonding material such as solder, bonded, and sealed with a mold resin provided on the substrate.

  Conventionally, as a general mold package of this kind, a substrate, a land made of metal provided on one surface of the substrate, a conductive bonding material provided on the land, and a conductive bonding material are provided. There has been proposed a component including a component bonded to a land via a conductive bonding material and a mold resin provided on one surface of the substrate for sealing the land, the conductive bonding material, and the component.

  In such a mold package, shear stress is applied to the mold resin at the interface between the end portion of the component and the mold resin, and the component side portion on the land, in particular, the conductive bonding material and the upper surface of the land and the mold resin The mold resin is easily peeled off at the interface.

  The mold resin peeling proceeds from the upper surface of the land to the one surface side of the substrate through the end portion, but when the peeling reaches the one surface of the substrate, stress is generated on the substrate and the substrate is easily damaged. Become. For this reason, it is desirable from the viewpoint of improving the reliability, for example, to reduce the speed at which the separation between the land and the mold resin reaches the substrate.

  Here, conventionally, in order to suppress the peeling between the mold resin and the land, a method of securing physical adhesion by roughening the land surface has been proposed (for example, see Patent Document 1).

JP 2003-163454 A

  However, for example, when performing wire bonding with a component on a substrate, it is necessary to provide a wire pad with Au plating on the surface in addition to the land on the substrate. Also, it is necessary to apply Au plating.

  Then, even if the land surface is roughened as described above, the land surface becomes smooth due to the Au plating, and the effect of suppressing peeling due to the above roughening becomes insufficient.

  The present invention has been made in view of the above problems, and is a mold resin in which components are mounted and bonded to a metal land on a substrate via a conductive bonding material such as solder and these are provided on the substrate. In a sealed mold package, even if the land surface is plated with Au, the object is to reduce the speed at which the separation between the land and the mold resin reaches the substrate as much as possible.

In order to achieve the above object, according to the first aspect of the present invention, a substrate (10), a land (20) made of metal provided on one surface (11) of the substrate, and a conductive material provided on the land. Bonding material (30), components (40, 41) provided on the conductive bonding material and bonded to the lands via the conductive bonding material, and lands, conductive bonding material and components provided on one surface of the substrate A mold resin (50) for sealing
The land is formed by sequentially laminating a first layer (21) made of metal and a second layer (22) made of metal from one side of the substrate, and the first layer is more than the second layer. By setting the plane size to be small, the end (21a) of the first layer is set to a position where the end (22a) of the second layer is retracted, and both the first and second layers are formed. Both end portions are in contact with the mold resin.

  According to this, even if the peeling of the mold resin occurs from the second layer side which is the component side of the land, and the peeling proceeds to the first layer side which is the substrate side, the second layer is the first layer. It is assumed that the peeling progress path is bent and the number of places where the peeling progress direction is changed increases, so that the peeling progress speed can be reduced. Therefore, according to the present invention, even if Au plating is applied to the land surface, the speed at which the separation between the land and the mold resin reaches the substrate can be made as slow as possible.

  Here, as in the invention according to claim 2, in the mold package according to claim 1, if the first layer and the second layer are made of different metals, the first layer And the second layer can be manufactured as different planar shapes.

  Further, in the invention according to claim 3, in the mold package according to claim 1 or 2, the contact surface with the mold resin in the first layer is compared with the contact surface with the mold resin in the second layer. It is characterized by being a surface having high adhesion to the mold resin.

  According to this, it is preferable because the adhesion between the first layer close to one surface of the substrate and the molding resin can be increased, and peeling of both can be made less likely to occur.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a schematic sectional drawing which shows the mold package concerning 1st Embodiment of this invention. It is an enlarged view of the A section surrounded by the circle in FIG. It is a schematic sectional drawing which shows the principal part of the mold package concerning 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the mold package concerning 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
The mold package according to the first embodiment of the present invention will be described with reference to FIGS. This mold package is mounted on a vehicle such as an automobile and is applied as a device for driving various electronic devices for the vehicle.

  The mold package of this embodiment is broadly divided into a substrate 10, a land 20 made of metal provided on one surface 11 of the substrate 10, a conductive bonding material 30 provided on the land 20, and a conductive bonding material. The components 40 and 41 provided on the substrate 30 and bonded to the land 20 via the conductive bonding material 30 and the land 20, the conductive bonding material 30 and the components 40 and 41 provided on the one surface 11 of the substrate 10 are sealed. And a mold resin 50 to be configured.

  The substrate 10 has a plate shape in which one of the front and back plate surfaces 11 and 12 is one surface 11 and the other is the other surface 12, and is specifically formed of a printed circuit board or a ceramic substrate. The substrate 10 may be a multilayer substrate or a single layer substrate, but the one surface 11 is a component mounting surface on which the components 40 and 41 are mounted. Here, the board 10 is a printed board made of resin.

  On one surface 11 of the substrate 10, a land 20 as a component mounting land on which the components 40 and 41 are mounted and a wire pad 60 to be wire bonded are provided. On the other hand, the other surface side wiring 70 is provided on the other surface 12 of the substrate 10.

  Here, the land 20 is formed by sequentially laminating a first layer 21 made of metal and a second layer 22 made of metal from the one surface 11 side of the substrate 10. Furthermore, the surfaces of the first layer 21 and the second layer 22 in the stacked state in the land 20, that is, the surfaces in contact with the conductive bonding material 30 and the mold resin 50 are from the Au plating 23 applied to the surfaces. It is structured.

  Here, the first layer 21 is based on Cu or the like, and the second layer 22 is based on a metal different from the first layer 21 such as Ni, Cr, or Sn. Further, the Au plating 23 only needs to have the outermost surface made of Au plating, for example, Ni / Pd / Au plating in which Ni plating, Pd plating, and Au plating are sequentially laminated from the base side, or Ni plating from the base side. Ni / Au plating in which Au plating is sequentially laminated can be employed.

  The first layer 21 and the second layer 22 are formed by forming a film by plating, attaching a foil, vapor deposition, sputtering, etc., and etching and patterning the film. The Au plating 23 is formed by performing normal electroplating, electroless plating, or the like on the surface of the stacked body after the layers 21 and 22 are stacked.

  In FIG. 1, the wire pad 60 and the other surface side wiring 70 are made of a metal such as Cu similar to the first layer 21, and are formed by the same film formation and patterning as the first layer 21. Is. The wire pad 60 has a surface plated with Au to ensure wire bonding.

  In such a substrate 10, after forming the first layer 21 and the second layer 22 that become the land 20, the wire pad 60, and the other surface side wiring 70 on the one surface 11 and the other surface 12 of the substrate 10, respectively. It is manufactured by forming the Au plating 23 on the necessary part. That is, in this embodiment, the surface of the land 20 is also made of the Au plating 23 in accordance with the Au plating 23 treatment on the surface of the wire pad 60.

  In the mold package shown in FIG. 1, the wire pad 60 and the other-side wiring 70 also have a two-layer structure including the first layer 21 and the second layer 22 similar to the land 20, and the surface thereof is the same. Of course, it may be made of Au plating 23.

  Then, on one surface 11 of the substrate 10, components 40 and 41 are electrically and mechanically bonded to the upper surface of the land 20 (that is, the surface of the second layer 22) via the conductive bonding material 30. . Here, the conductive bonding material 30 is made of solder, a conductive adhesive, or the like.

  In the present embodiment, the components 40 and 41 include an active element 40 such as an IC chip located on the left side in FIG. 1 and a passive element 41 such as a capacitor and a resistor located on the right side in FIG. Here, the active element 40 and the wire pad 60 are connected by a bonding wire 80 and are electrically connected. This bonding wire 80 is made of Au, Al, or the like, and is formed by ordinary wire bonding.

  The mold resin 50 is made of a normal mold material such as an epoxy resin, and is formed by, for example, a transfer mold method, a compression mold method, or the like. Here, the mold resin 50 seals the other surface 12 side in addition to the one surface 11 of the substrate 10.

  In the mold package of this embodiment, after preparing the substrate 10 having the land 20, the wire pad 60, and the other surface side wiring 70, and bonding the components 40 and 41 to the substrate 10 via the conductive bonding material 30, It is manufactured by performing wire bonding and sealing it with a mold resin 50.

  Here, with reference to FIG. 2 as well, the details of the connecting portion between the components 40 and 41 and the land 20 will be described. The detailed portion of the connecting portion described below is common to both the active element 40 and the passive element 41. It is.

  In the present embodiment, as shown in FIGS. 1 and 2, the planar size of one surface 11 of the substrate 10 is larger in the first layer 21 of the land 20 than in the conductive bonding material 30. The end 21 a of one layer 21 protrudes beyond the end 30 a of the conductive bonding material 30. For example, when the second layer 22 is a plane rectangle, the conductive bonding material 30 that is slightly smaller than the second layer 22 is provided on the second layer 22.

  As shown in FIGS. 1 and 2, in the land 20 of this embodiment, the first layer 21 has a smaller planar size than the second layer 22. As a result, the end portion 21 a of the first layer 21 is in a position where the end portion 22 a of the second layer 22 is retracted.

  The surface of the end portion 21a of the first layer 21 (here, Au plating 23) and the surface of the end portion 22a of the second layer 22 (here, Au plating 23) are both in contact with the mold resin 50. It is sealed.

  For example, when the second layer 22 forms a planar rectangle, the first layer 21 therebelow can have a planar rectangle that is slightly smaller than that. In this case, each side of the first layer 21 is in a position retracted from each side of the second layer 22.

  In order to allow the mold resin 50 to enter the lower side of the second layer 22 so that the mold resin 50 contacts the end portion 21a of the first layer 21, the thickness of the first layer 21 is set to the thickness of the first layer 21. It is necessary to ensure such a thickness. Considering this point, the thickness of the first layer 21 is not limited, but is preferably 20 nm or more, for example.

  By the way, according to this embodiment, the land 20 is formed by sequentially laminating the first layer 21 and the second layer 22, and the end 21 a of the first layer 21 is the end of the second layer 22. The position is retracted from 22a.

  Here, as indicated by a solid arrow H1 in FIG. 2, the mold resin 50 is peeled off from the second layer 22 side on the parts 40 and 41 side of the land 20, and this peeling is caused on the substrate 10 side. Suppose that it progresses to a certain first layer 21 side. At this time, conventionally, since the substrate 10 side of the end portion of the land 20 is not retracted as in the present embodiment, the peeling is directly performed on one surface of the substrate 10 as indicated by a broken-line arrow H2 in FIG. 11 is reached and the substrate 10 is damaged.

  On the other hand, in this embodiment, in the land 20, the mold resin 50 is in contact with both the end portion 21 a of the first layer 21 and the end portion 22 a of the second layer 22. The portion 21 a is a position where the end portion 22 a of the second layer 22 is retracted. Therefore, the interface between the end portion of the land 20 and the mold resin 50 has a shape having more bent portions than in the past.

  For example, in the present embodiment, as shown in FIG. 2, a bent portion M <b> 1 constituted by a corner portion on the lower surface side at the end portion 21 a of the first layer 21, a lower surface of the first layer, and a second layer The two bent portions including the bent portion M <b> 2 constituted by the end portions of the two are added in comparison with the conventional one.

  Therefore, in this embodiment, since the number of places where the peeling progress direction is changed is larger than that in the past, the speed of the peeling can be reduced. Therefore, according to this embodiment, even if the surface of the land 20 is Au-plated, the speed at which the separation between the land 20 and the mold resin 50 reaches the one surface 11 of the substrate 10 is made as slow as possible. Can do. Further, the reliability of the mold package can be improved.

  As described above, in the present embodiment, the first layer 21 and the second layer 22 in the land 20 are made of different metals. This is because it is easy to manufacture the first layer 21 and the second layer 22 with different planar shapes. This will be further described.

  As described above, a part of the land 20 including the first layer 21 and the second layer 22 is specifically formed after the first layer 21 is formed and patterned by etching. The second layer 22 is formed on the entire surface and is patterned by etching.

  Here, in the land 20 of the present embodiment, the first layer 21 and the second layer 22 may be made of the same metal. However, in that case, when the second layer 22 on the already patterned first layer 21 is patterned with the etching solution, both layers 21 and 22 are etched with the same etching solution, so the lower first layer 21 is etched. A device such as masking the layer 21 is required.

  In that regard, if the first layer 21 and the second layer 22 are different metals, the etching liquids of the second layer 21 are not etched by the etching liquid of the second layer 21 because the etching liquids are different from each other. You can Therefore, both the first layer 21 and the second layer 22 can be easily controlled to have a desired planar shape, and land formation is facilitated.

(Second Embodiment)
The second embodiment of the present invention will be described with reference to FIG. 3. In the present embodiment, differences from the first embodiment will be mainly described.

  In the first embodiment, as shown in FIG. 2, in the land 20, both surfaces of the first layer 21 and the second layer 22 that are stacked are configured by the Au plating 23. As a result, both the first layer 21 and the second layer 22 had the Au plating 23 on the entire surface in contact with the mold resin 50.

  On the other hand, as shown in FIG. 3, in the present embodiment, the surface of the second layer 22 that contacts the mold resin 50, that is, the surface of the end 22 a of the second layer 22 is Au plated 23. Instead, the base metal constituting the second layer 22 is the surface. Such a configuration can be realized by masking the end 21a of the first layer 21 during the Au plating 23 treatment.

  The Au plating 23 originally has low adhesion to the mold resin 50. Therefore, according to this embodiment, the contact surface with the mold resin 50 in the first layer 21 (without the Au plating 23) is the contact surface with the mold resin 50 in the second layer 22 (with the Au plating 23). Compared to the mold resin 50, the surface can be made higher.

  And according to this embodiment, since the adhesive force of the 1st layer 21 near the one surface 11 of the board | substrate 10 and the mold resin 50 is improved, both of these can be made hard to generate | occur | produce and the mold resin 50 can be made. Is preferable in that it is difficult to reach the surface 11 of the substrate 10.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. In the present embodiment, as in the second embodiment, the contact surface of the first layer 21 with the mold resin 50 is closer to the mold resin 50 than the contact surface of the second layer 22 with the mold resin 50. It is a surface with high properties.

  In the present embodiment, as shown in FIG. 4, the end portion 21 a of the first layer 21 to which the Au plating 23 is not applied is further a roughened surface. Specifically, Ni roughening plating treatment or the like may be performed. According to this, the further improvement of the adhesiveness of the edge part 21a of the 1st layer 21 and the mold resin 50 can be anticipated.

(Other embodiments)
If possible, the Au plating 23 may be omitted. That is, the entire surface of the land 20 is not subjected to the Au plating 23, and the base metal of the first layer 21 and the second layer 22 may constitute the surface of the land 20. For example, such a configuration can be adopted in a case where the mold package does not have the wire pad 60.

  Moreover, in each said figure, the edge part 30a of the electroconductive joining material 30 was retracted rather than the edge part 22a of the 2nd layer 22 in the land 20. FIG. However, if the first layer 21 is not reached, the end 30a of the conductive bonding material 30 hangs down from the upper surface of the second layer 22 to the end 22a of the second layer 22, so that the second The layer 22 may protrude beyond the end 22a.

  Further, the present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope described in the claims. The above embodiments are not irrelevant to each other, and can be combined as appropriate unless the combination is clearly impossible, and the above embodiments are not limited to the illustrated examples. Absent. In each of the above-described embodiments, it is needless to say that elements constituting the embodiment are not necessarily essential unless explicitly stated as essential and clearly considered essential in principle. Yes. Further, in each of the above embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is clearly limited to a specific number when clearly indicated as essential and in principle. The number is not limited to the specific number except for the case. Further, in each of the above embodiments, when referring to the shape, positional relationship, etc. of the component, etc., the shape, unless otherwise specified and in principle limited to a specific shape, positional relationship, etc. It is not limited to the positional relationship or the like.

DESCRIPTION OF SYMBOLS 10 Substrate 11 One side of substrate 20 Land 21 First layer 21a End portion of first layer 22 Second layer 22a End portion of second layer 30 Conductive bonding material 40 Active element 41 as component 41 Passive as component Element 50 Mold resin

Claims (3)

A substrate (10);
A land (20) made of metal provided on one surface (11) of the substrate;
A conductive bonding material (30) provided on the land;
Components (40, 41) provided on the conductive bonding material and bonded to the land via the conductive bonding material;
A mold resin (50) provided on one surface of the substrate for sealing the land, the conductive bonding material, and the component;
The land is formed by sequentially laminating a first layer (21) made of metal and a second layer (22) made of metal from one side of the substrate,
The first layer has a planar size smaller than that of the second layer, so that the end (21a) of the first layer is recessed more than the end (22a) of the second layer. A mold package characterized in that both ends of the first and second layers are in contact with the mold resin.   The mold package according to claim 1, wherein the first layer and the second layer are made of different metals.   The contact surface of the first layer with the mold resin is a surface having higher adhesion to the mold resin than the contact surface of the second layer with the mold resin. The mold package according to claim 1 or 2.

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