JPH10256433A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the semiconductor device and the mounting method thereof, which can enlarge the bonding area of a package and can improve the temporary fixing adhesive property with a mounted substrate. SOLUTION: This is the surface mounting type package 1, which can be mounted on a mounting substrate in the planar pattern. Outer leads 2 are made to protrude from the side surface of the package 1. The outer leads 2 have the package structure molded in the gull-wing shape (L shape). In this package 1, a projection 3 having the square pole shape with the specified size and the specified thickness weight is formed along the central line of the rear surface for temporarily fixing the surface mounting type package 1 to the mounting substrate beforehand so that the mounted surface mounting type package 1 is not dropped when the mounting substrate is inverted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device technology using a surface mount type package, and more particularly to a semiconductor device suitable as a countermeasure against temporary adhesion failure when a package is mounted on a mounting board, and is effectively applied to a semiconductor device mounting method. Technology.

[0002]

2. Description of the Related Art For example, as a technique studied by the present inventor, when a package is mounted on a mounting board by a flow soldering method in a mounting process of a surface mounting type package, the mounting is performed when the mounting board is inverted. In order to prevent the package from dropping, a method of temporarily fixing the mounting surface of the package to the mounting substrate in advance with an adhesive before soldering can be considered.

[0003] With regard to the mounting technology of such a surface mounting type package, for example, Nikkei BP, May 1993
And other documents such as “Practical Course VLSI Packaging Technology (1)” published on March 31, P241 to P276.

[0004]

By the way, in the above mounting technology of the surface mounting type package, in order to improve the temporary fixing property between the package and the mounting board, for example, an adhesive suitable for the size of the package is used. It is important to select an adhesive in accordance with the amount of the material and the material of the package, and the adhesiveness between the package and the mounting board by the adhesive may be a problem.

Accordingly, an object of the present invention is to increase the bonding area by providing projections on the mounting surface of the package without depending on the amount of the adhesive and the selection of the adhesive as described above. It is an object of the present invention to provide a semiconductor device and a mounting method thereof capable of improving the temporary adhesion with the semiconductor device.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the semiconductor device according to the present invention is applied to a surface mount type package, and at least one semiconductor device is attached to a mounting surface of the package for temporary fixing when the package is mounted on a mounting substrate. Are provided. Thereby, the bonding area between the package and the mounting substrate can be increased via the protrusion, so that the temporary fixing adhesiveness between the package and the mounting substrate can be improved.

In particular, by forming one or a plurality of protrusions in a predetermined shape and size, the shape, size and number of the protrusions can be adjusted in accordance with factors which influence the adhesion such as the size and material of the package. Can be arbitrarily changed, so that an optimal temporary fixing adhesiveness corresponding to the package and the mounting substrate can be obtained.

Further, when the projections are formed at the same time when the package is sealed with the mold, it can be easily coped with by changing the mold dies. Further, a semiconductor device capable of improving the temporary fixing adhesiveness by simply adhering the projections after the package is completed can be obtained.

Further, in the method of mounting a semiconductor device according to the present invention, when mounting a surface mount type package having at least one protrusion provided on a mounting surface to a mounting substrate, the package is mounted on the mounting substrate via the protrusion. After the temporary fixing, the package is temporarily inverted and the mounting substrate is inverted, and the back surface of the mounting substrate is subjected to flow soldering and reflow soldering. As a result, mounting with improved temporary adhesion between the package and the mounting board is possible.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, the same members are denoted by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1) FIG. 1 is a schematic perspective view showing a semiconductor device according to Embodiment 1 of the present invention from the back, and FIG.
3 is a cross-sectional view showing the internal structure of the semiconductor device of the first embodiment, FIG. 3 is a flow chart for explaining a method of manufacturing the semiconductor device and a schematic diagram corresponding thereto, and FIG. 4 is a view for explaining a mounting method of the semiconductor device. 5A and 5B are a cross-sectional view and an enlarged cross-sectional view showing a state in which the semiconductor device is mounted on a mounting board.

First, the configuration of the semiconductor device according to the first embodiment will be described with reference to FIG.

The semiconductor device according to the first embodiment is, for example, a surface mount type package 1 that can be mounted on a mounting board in a planar manner.
The outer lead 2 is projected from the side surface of the package 1 and has a package structure in which the outer lead 2 is formed in a gull wing shape (L shape).

For example, as a package 1 having a gull-wing outer lead 2, an SOP (Small Out-line Packag) having an outer lead 2 projecting in two directions is provided.
e), this thin TSOP (Thin Small Out-line Packa)
ge), QFP with outer leads 2 projected in four directions
(Quad Flat Package), this thin TQFP (Thin Q
uad Flat Package).

In order to prevent the surface-mounted package 1 mounted on the semiconductor device from being dropped when the mounting substrate is inverted, the surface-mounted package 1 is temporarily fixed to the mounting substrate in advance. As shown in the figure, a rectangular pillar-shaped projection 3 having a predetermined size and a predetermined thickness is formed along the center line of the back surface.

This semiconductor device has an internal structure as shown in FIG. 2, for example. A semiconductor chip 5 is bonded and fixed to a die pad portion of a lead frame 4.
The bonding pad and the inner lead 6 of the lead frame 4 are connected by a gold wire 7 to form a plastic package molded and sealed with a thermosetting plastic resin 8.

Next, the operation of the first embodiment will be described with reference to FIG. In FIG. 3, the diagram on the right is a schematic diagram corresponding to the flow on the left.

First, in a die bonding step of the semiconductor chip 5, a paste 9 is applied to a die pad portion of the lead frame 4 by a dispenser, and the semiconductor chip 5 adsorbed by the collet 10 is transferred to the die pad portion, and adhered and fixed by pressing. (Step 301).

After the wafer processing step of forming a predetermined integrated circuit such as memory and logic on the semiconductor wafer is completed, the semiconductor chip 5 is subjected to a back grinding step of grinding the back surface of the semiconductor wafer to a predetermined thickness, Further, it is formed by completing a dicing step of cutting into individual semiconductor chips 5.

Further, in the wire bonding step, a ball is formed at the tip of the gold wire 7 and the bonding pad of the semiconductor chip 5 and the inner lead 6 of the lead frame 4 are formed by ultrasonic wave and thermocompression from the capillary 11.
Are connected by the gold wire 7 (step 302).

Subsequently, in a mold sealing step, the tablet-shaped plastic resin 8 is pre-heated to
After that, the plastic resin 8 is transferred by applying pressure by a plunger, and curing is performed inside the mold 12 until the plastic resin 8 is thermally cured (step 303).

In this case, the projections 3
As the lower mold of the mold 12, a concave part 13 having a predetermined size and a predetermined thickness and having a quadrangular prism shape having a predetermined thickness is used. For example, the width dimension of the projection 3 is set to be equal to or less than the length of the short side of the package 1 and the thickness is set to be equal to or less than the dimension between the mounting board and the package 1, that is, the so-called stand-off height.

Then, in the lead forming step, the plastic package can be completed by cutting the package 1 and the outer lead 2 from the frame of the lead frame 4 and forming the outer lead 2 into a gull wing shape (step 304). ).

Next, an outline of a method of mounting a semiconductor device is shown in FIG.
It will be described based on. In FIG. 4, the diagram on the right is a schematic diagram corresponding to the flow on the left. Here, for example, a single-sided reflow process by a mixed mounting of a surface mount type package and a lead insertion mount type package will be described.

First, in the reflow soldering process for the front surface, the solder paste 15 is printed on the pattern of the mounting substrate 14 by a printing machine (step 401), and the surface mounting type package 16 without the projections 3 is mounted on the mounter (step 401). Step 402). At this time, the surface mount type package 16
The outer lead 2 is mounted on the printed solder paste 15.

Then, the substrate is placed in a reflow furnace and
Is heated, the solder paste 15 is melted, and the outer leads 2 and the pattern are joined (step 40).
3). Thereby, the surface mount type package 16 without the protrusion 3 can be mounted on the surface of the mounting substrate 14.

Subsequently, the package 1 of the surface mounting type on the back surface
In the temporary fixing step, the mounting substrate 14 is inverted (step 404), and an adhesive 17 such as an epoxy-based adhesive is applied with a dispenser (step 405), and the surface mounting type having the protrusions 3 according to the structure of the first embodiment is used. Is temporarily fixed. The purpose is to prevent the package 1 adhered to the back surface from falling.

That is, the surface mount type package 1 is mounted by a chip mounter (step 406), and the entire mounting substrate 14 is heated in a curing furnace to cure the adhesive 17 (step 407). Thereby, the surface mounting type package 1 having the projections 3 can be temporarily fixed to the back surface of the mounting substrate 1.

In this case, in the surface mount type package 1 having the structure of the first embodiment, since the projection 3 is formed on the back surface of the package 1, the package 3 is bonded to the mounting board 14 via the projection 3. The area can be increased.
That is, as shown in FIG. 5, the surface mounting type package 1 can be temporarily fixed to the mounting board 14 in a range W equal to or larger than the size of the projection 3.

Further, in the backside flow soldering step, the mounting substrate 14 is again turned upside down (step 40).
8) Insert the lead insertion package 18 (step 409). Then, a flux is applied to the back surface by a flow soldering apparatus, and flow soldering is performed (step 410). Thereby, the surface mount type package 1 having the protrusions 3 can be mounted on the back surface of the mounting substrate 1, and the lead insertion mounting type package 18 can be mounted on the front surface of the mounting substrate 14.

As described above, first, the surface mount type package 16 having no protrusions 3 on the front surface is reflow-soldered, and then the surface mount type package 1 having the protrusions 3 on the back surface is soldered.
Is temporarily fixed, a package 18 of a lead insertion mounting type is inserted into the front surface, and the back surface is subjected to flow soldering to complete the one-sided reflow process, and the surface mounting type package 16 without the projections 3 and the surface mounting type with the projections 3 Package 1 and the lead insertion mounting type package 18 can be mixedly mounted on the mounting board 14.

Therefore, according to the semiconductor device of the first embodiment, the quadrangular prism-shaped projections 3 are formed along the center line of the back surface of the package 1, and the package 1 is connected to the package 1 via the projections 3. The bonding area with the mounting substrate 14 is increased, and the temporary adhesion between the package 1 and the mounting substrate 14 can be improved.

The protrusion 3 can be formed at the same time when the package 1 is molded and sealed by using a lower mold having a rectangular column-shaped recess 13 as the mold 12. Thereby, it is possible to easily cope with the manufacture of a semiconductor device capable of improving the temporary fixing adhesiveness.

Further, by providing the projections 3 on the back surface of the package 1, the strength of the package 1 itself can be improved, and an ejector for projecting the package 1 from the mold 12 so as to separate from the mold. In the package 1 having no pins (E-pins), E-pins can be provided, and further, the resin thickness by the plastic resin 8 is increased, and the effect of reducing stress by the E-pins can be obtained.

(Second Embodiment) FIG. 6 is a schematic perspective view showing a semiconductor device according to a second embodiment of the present invention from the back, and FIG.
Is a schematic perspective view showing a modified example of the semiconductor device of the second embodiment from the back, and FIG. 8 is a cross-sectional view showing a state where the semiconductor device of the second embodiment is mounted on a mounting board.

The semiconductor device according to the second embodiment is a surface-mount type package that can be mounted on a mounting board in a planar manner, similarly to the first embodiment. The difference from the first embodiment is that This is a point that the outer lead projecting from the side surface is formed into a J-shape, and a plurality of protrusions provided on the back surface of the package are formed.

That is, the package 1 of the second embodiment
For example, as shown in FIG. 6, a rectangular prism-shaped projection 3a of a predetermined size and a predetermined thickness is formed along a center line on the back surface of a package 1a having a J-shaped outer lead 2a. Are formed in three pieces. In addition, this projection 3
The number of a is not limited to three, but may be two, four or more.

Further, the shape of the projection 3a may be other than the square pillar, such as a cylindrical projection 3b as shown in FIG.
The size and number can be arbitrarily changed.

As the package 1a having the J-shaped outer leads 2a as in the second embodiment, an SOJ (Small Out-
lineJ-leaded Package), outer lead 2 in four directions
QFP (QuadFlat J-leaded Package)
This QFP has PLCC (Plastic Leaded)
Chip Carrier) and CLCC (Ceramic Leaded Chip Ca)
rrier).

Therefore, according to the semiconductor device of the second embodiment, the rectangular prism is formed along the center line on the back surface of the package 1a.
By forming a plurality of projections 3a and 3b having a shape such as a column, as shown in FIG.
By temporarily fixing a and 3b to the mounting board 14 with the adhesive 17, the bonding area between the package 1a and the mounting board 14 via the protrusions 3a and 3b is increased, as in the first embodiment. Temporary adhesion between the substrate and the mounting substrate 14 can be improved. The protrusions 3a,
3b is a quadrangular prism when the package 1a is molded and sealed.
It can be formed at the same time by using a mold in which a concave portion having a shape such as a column is formed.

In particular, as in the second embodiment, the protrusion 3
When a and 3b are formed in a plurality, the package 1a
The shape of the projections 3a and 3b corresponding to the size and material of the
Since the dimensions and number can be changed arbitrarily,
It is possible to obtain the optimum temporary adhesiveness corresponding to the package 1a and the mounting board 14.

(Embodiment 3) FIG. 9 is a schematic perspective view showing a semiconductor device according to Embodiment 3 of the present invention from the back.

The semiconductor device according to the third embodiment is a surface mount type package that can be mounted on a mounting board in a planar manner, similarly to the first embodiment. The difference from the first embodiment is that Form a plurality of protrusions to be provided on the back,
In addition, this projection is not formed at the same time as molding the package, but is formed by bonding after molding.

That is, the package 1 of the third embodiment
For example, as shown in FIG. 9, after the package 1b having the gull wing-shaped outer lead 2b is completed, the projections 3c and 3d are bonded using an adhesive.
Along the center line of the back surface, projections 3c and 3d of a predetermined size and a predetermined thickness, such as a square pillar or a cylinder, are formed by three.
Or five. The protrusions 3c,
The shape, size, number, and the like of 3d can be arbitrarily changed.

Therefore, according to the semiconductor device of the third embodiment, the protrusions 3 are adhered after the mold sealing, and are shaped like quadrangular prisms, cylinders, or the like along the center line on the back surface of the package 1b.
By forming a plurality of c and 3d, the package 1 is formed via the protrusions 3c and 3d in the same manner as in the first embodiment.
b and the mounting area between the mounting substrate and the package
It is possible to improve the temporary fixing adhesiveness between b and the mounting substrate.

In particular, as in the third embodiment, the protrusion 3
In the case where c and 3d are formed by bonding after molding, the protrusions 3c and 3d having shapes, dimensions and numbers corresponding to the size and material of the package 1b are formed.
By simply adhering after completion of b, it is possible to obtain a semiconductor device capable of improving temporary adhesion.

As described above, the invention made by the inventor has been specifically described based on the first to third embodiments. However, the present invention is not limited to the above-described embodiment, and does not depart from the gist of the invention. It is needless to say that various changes can be made.

For example, in the above embodiment, the case where the protrusions are formed along the center line of the back surface of the package has been described. However, the present invention is not limited to this. In the case where the projections are formed by polygonal pillars, the shape, dimensions and number of the projections can be arbitrarily changed.

[0051]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1) By providing at least one protrusion on the mounting surface of the package, the bonding area between the package and the mounting substrate can be increased via the protrusion.
The temporary adhesion between the package and the mounting substrate can be improved.

(2) The protrusion is formed in a predetermined shape and size.
By forming them individually or in multiples, the shape, size and number of projections can be changed arbitrarily according to factors that affect the adhesion such as the size and material of the package. It is possible to obtain the optimal temporary fixing adhesiveness corresponding to the above.

(3) By forming the projections simultaneously with the package sealing, it is possible to easily cope with the improvement of the temporary adhesion of the semiconductor device by changing the mold.

(4) By forming the protrusions by bonding after the package is molded, it is possible to easily cope with the improvement of the temporary fixing adhesiveness of the semiconductor device by simply bonding the protrusions after the package is completed. It becomes possible.

(5) When mounting a surface mount type package having at least one protrusion provided on a mounting surface on a mounting board, the package is temporarily fixed to the mounting board via the protrusion, and then the mounting board is mounted. By performing the flow soldering and the reflow soldering on the back surface, it is possible to mount the package on the mounting board with the improved temporary fixing adhesiveness between the package and the mounting board.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a semiconductor device according to a first embodiment of the present invention from a back surface.

FIG. 2 is a sectional view showing an internal structure of the semiconductor device according to the first embodiment of the present invention;

FIG. 3 is a flow chart illustrating a method of manufacturing the semiconductor device according to the first embodiment of the present invention and a schematic diagram corresponding thereto.

FIG. 4 is a flow chart for explaining a method of mounting the semiconductor device according to the first embodiment of the present invention and a schematic diagram corresponding thereto;

FIGS. 5A and 5B are a cross-sectional view and an enlarged cross-sectional view showing a state where the semiconductor device according to the first embodiment of the present invention is mounted on a mounting board.

FIG. 6 is a schematic perspective view showing a semiconductor device according to a second embodiment of the present invention from the back surface.

FIG. 7 is a schematic perspective view showing a modified example of the semiconductor device according to the second embodiment of the present invention from the back surface.

FIG. 8 is a cross-sectional view showing a state where the semiconductor device according to the second embodiment of the present invention is mounted on a mounting board.

FIG. 9 is a schematic perspective view showing a semiconductor device according to a third embodiment of the present invention from a back surface.

[Explanation of symbols]

 1, 1a, 1b Package 2, 2a, 2b Outer lead 3, 3a, 3b, 3c, 3d Projection 4 Lead frame 5 Semiconductor chip 6 Inner lead 7 Gold wire 8 Plastic resin 9 Paste 10 Collet 11 Capillary 12 Mold 13 Recess 14 Mounting board 15 Solder paste 16 Package 17 Adhesive 18 Package

Claims (6)

[Claims] 1. A semiconductor device using a surface mount type package, wherein at least one projection is provided on a mounting surface of the package for temporary bonding when the package is mounted on a mounting substrate. A semiconductor device characterized by the above-mentioned. 2. The semiconductor device according to claim 1, wherein said projection is formed as a single piece having a predetermined shape and size. 3. The semiconductor device according to claim 1, wherein the plurality of protrusions are formed in a predetermined shape and size. 4. The semiconductor device according to claim 2, wherein the projection is formed simultaneously with molding the package. 5. The semiconductor device according to claim 2, wherein the projection is formed by bonding the package after molding and sealing the package. 6. A step of temporarily fixing the package to the mounting board via the projection when mounting a semiconductor device using a surface mount type package having at least one projection provided on a mounting surface on the mounting board. And a step of inverting the mounting substrate to which the package is temporarily fixed, and a step of subjecting the back surface of the mounting substrate to flow soldering and reflow soldering.