Patent Application
20110074048
The present invention relates to a semiconductor device and a method of manufacturing the same.
In a typical semiconductor device, a semiconductor element mounted on the surface of a substrate is covered with a molding resin body. The molding resin body is typically formed as follows: the substrate on which the semiconductor element is mounted is clamped with dies and then molding resin is injected into a die cavity.
In the related art, it has been proposed to taper or round the sides of a die cavity to prevent a die from damaging a substrate during the formation of a molding resin body (e.g., see Japanese Patent Laid-Open No. 11-67801). To be specific, the sides of the die cavity are tapered or rounded and thus a stress concentration is reduced on a boundary portion between the side of the die cavity and the substrate contact surface of the die, so that damage is prevented on the substrate. Hereinafter, the boundary portion between the side of the die cavity and the substrate contact surface of the die will be called the inner circumference of the die.
As has been discussed, in the related art, the sides of the die cavity are tapered or rounded to prevent the die from damaging the substrate. However, in the presence of wiring under the inner circumference of the die, even the tapered or rounded sides of the die cavity may damage the substrate.
Specifically, a typical substrate includes wiring formed on the surface of a base material, and a solder resist covering the surface of the base material and the wiring. The wiring is not easily compressed by a clamping load applied from a die, unlike the solder resist. Thus in the presence of wiring under the inner circumference of the die, damage such as cracks like grooves may occur on the solder resist covering the wiring.
The present invention has been devised in view of the problem. An object of the present invention is to provide a semiconductor device and a method of manufacturing the same which can suppress the possibility of damage on a substrate when a molding resin body is formed using dies.
A semiconductor device of the present invention includes: a base material; a semiconductor element mounted on the base material; a solder resist covering a region outside the mounted semiconductor element on the base material; and a molding resin body covering the semiconductor element and a part of the solder resist together, wherein the solder resist has a recessed portion at the bottom of the outer circumference of the molding resin body and the molding resin body is partially embedded in the recessed portion.
The semiconductor device of the present invention, wherein the recessed portion may have the bottom away from the bottom of the solder resist.
The semiconductor device of the present invention, wherein the solder resist may have a multilayer structure of at least two layers. In this case, the recessed portion may be formed by partially removing the upper layer of the solder resist. Moreover, in this case, the recessed portion may be formed by cylindrically removing a part of the upper layer of the solder resist.
The semiconductor device of the present invention, wherein the molding resin body may contain filler. In this case, the recessed portion may have dimensions smaller than a value indicating the maximum particle size of the filler.
A method of manufacturing a semiconductor device according to the present invention, in which during the formation of a molding resin body covering a semiconductor element mounted on a substrate, the substrate on which the semiconductor element is mounted is clamped with dies and then molding resin is injected into the cavity of the die, the method including the step of, when the substrate is clamped with the dies, causing the inner circumstance of the die to face a recessed portion formed in advance on a solder resist covering the substrate.
The method of manufacturing a semiconductor device according to the present invention, wherein the solder resist may have a multilayer structure of at least two layers. In this case, the recessed portion may be formed by partially removing the upper layer of the solder resist. Further, in this case, the recessed portion may be a through hole formed on the upper layer of the solder resist.
The method of manufacturing a semiconductor device according to the present invention, wherein the recessed portion may have dimensions smaller than a value indicating the maximum particle size of filler contained in the molding resin body.
A preferred embodiment of the present invention can suppress the possibility of damage on a substrate when a molding resin body is formed using dies. In other words, a solder resist has a recessed portion at the bottom of the outer circumference of the molding resin body and the molding resin body is partially embedded in the recessed portion. In order to manufacture a semiconductor device configured thus, the inner circumference of the die has to face the recessed portion. With this configuration, a clamping load from the inner circumference of the die is not directly applied to the solder resist, thereby suppressing damage on the substrate.
An embodiment of the present invention will be described below in accordance with the accompanying drawings. The aforementioned members will be indicated by the same reference numerals and the explanation thereof is omitted when necessary.
As shown in
The substrate 1 includes a base material 5, a plurality of wires 6 formed on the top surface of the base material 5, and a plurality of connection terminals 7 formed on the underside of the base material 5. In the base material 5, vias 8 and inner wires 9 are formed. The vias 8 and the inner wires 9 connect the wires 6 on the top surface of the substrate 1 and the connection terminals 7 on the underside of the substrate 1. Further, external connection terminals 10 shaped like balls are connected to the connection terminals 7.
On the top surface and the underside of the substrate 1, a solder resist 11a and a solder resist lib are formed, respectively. To be specific, the solder resist 11a on the top surface of the substrate 1 is formed over a region outside the semiconductor mounting part 4 and on the outer circumference of the semiconductor mounting part 4. The solder resist 11b on the underside of the substrate 1 is formed in a region other than the region of the external connection terminals 10.
The wires 6 are formed from the inside to the outside of the substrate 1. The wires 6 are each made up of a covered portion that is covered with the solder resist 11a and an uncovered portion that is not covered with the solder resist 11a. The uncovered portions act as connection terminals 12. In other words, the connection terminals 12 are formed in the semiconductor mounting part 4 and the wires 6 have the covered portions connected to the connection terminals 12 and formed from the inside to the outside of the semiconductor mounting part 4.
The semiconductor element 2 is formed in the semiconductor mounting part 4. To be specific, the semiconductor element 2 is fixed on the substrate 1 with, e.g., an adhesive 13. Terminals 14 of the semiconductor element 2 and the connection terminals 12 on the top surface of the substrate 1 are electrically connected via thin metallic wires 15.
The molding resin body 3 integrally covers and resin-molds the semiconductor element 2, the solder resist 11a on the top surface of the substrate 1 and in the semiconductor mounting part 4, the connection terminals 12, and the thin metallic wires 15.
As shown in
The molding resin body 3 is partially embedded in the recessed portion 16 thus, so that moisture or the like from the outside of the molding resin body 3 passes through a long path formed of an outer wall 16a, a bottom wall 16b, and an inner wall 16c of the recessed portion 16. Thus the moisture or the like hardly enters the semiconductor mounting part 4.
The dimensions of the recessed portion 16 will be discussed below. As shown in
The formation position and the cross-sectional shape of the recessed portion 16 are preferably set such that from the bottom of the outer circumference of the molding resin body 3, a region of the recessed portion 16 on the outer side of the substrate 1 is formed larger than the other region of the recessed portion 16 on the inner side of the substrate 1. With this configuration, the molding resin easily flows into the recessed portion 16 during the formation of the molding resin body 3. Thus the recessed portion 16 is more reliably filled with a part of the molding resin body 3. Further, the upper corners of the recessed portion 16 are preferably rounded. This configuration improves the strength of the recessed portion 16 against damage.
The recessed portion 16 can be formed by partially removing the upper layer of the solder resist 11a on the top surface of the substrate 1, the solder resist 11a having a multilayer structure of at least two layers. With this configuration, the underside of the recessed portion 16 is separated from the top surfaces of the wires 6, so that moisture or the like hardly enters the wires 6 from the recessed portion 16.
The following will describe another example of the recessed portion 16. As shown in
In the manufacturing process of the semiconductor device configured thus, a process of forming the molding resin body 3 will be discussed below.
As shown in
The position of the substrate 1 is set on the lower die 19 as follows: when the substrate 1 is clamped, as shown in
Outside the recessed portion 16, a clamping load is applied from the upper die 18 to the solder resist 11a. However, the contact surface of the upper die 18 with the substrate is flat outside the recessed portion 16. Thus an extremely large clamping load is not applied outside the recessed portion 16, and the solder resist 11a and the base material 5 are not damaged outside the recessed portion 16.
The molding resin is injected into the cavity of the upper die 18 in a state in which the upper die 18 and the lower die 19 are set thus. At this point, conditions such as the feed rate and pressure of the molding resin are adjusted to allow the molding resin to flow into the recessed portion 16. Thus the molding resin body 3 is formed so as to integrally cover the semiconductor element 2, the solder resist 11a in the semiconductor mounting part 4, the connection terminals 12, and the thin metallic wires 15, and fill the recessed portion 16.
The recessed portion 16 may be integrally formed over the bottom of the outer circumference of the molding resin body 3 or multiple recessed portions 16 may be separately formed over the bottom of the outer circumference of the molding resin body 3.
The semiconductor device and the method of manufacturing the same according to the present invention can suppress the possibility of damage on the substrate when the molding resin body is formed using the dies, and thus the present invention is widely applicable to the configurations of semiconductor devices used for various kinds of electronic equipment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-152347 | Jun 2008 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2009/002584 | Jun 2009 | US |
| Child | 12964253 | US |
