JP6815217B2 - Semiconductor device - Google Patents

Description

The present invention relates to a leadless type semiconductor device in which a semiconductor chip is sealed with a resin.

In recent years, due to the remarkable spread of smartphones, tablet PCs, and wristwatch-type wearable terminals, semiconductor devices housed in resin-sealed semiconductor packages of electronic components mounted on these devices are also required to be small, thin, and low cost. Has been done.

There is a high demand for extremely small resin-sealed semiconductor packages for these terminal products, and among them, the demand for leadless type small and thin semiconductor packages is increasing, and it is possible to reduce the total thickness of semiconductor packages. Not only the thickness of the lead frame itself used for the semiconductor package tends to be thin. The lead frame thickness used to be 200 micrometers, but now it is 80 to 125 micrometers.

As a leadless type small semiconductor package, there is SON (Small Outline Non-Leaded Package), which exposes a metal surface as a lead on the lower surface side of the package which is a mounting surface without projecting the lead from the side surface of the package. It is a semiconductor package.

FIG. 12 is a perspective view of a semiconductor device 1 using a leadless type resin-sealed semiconductor package.
The leadless type semiconductor package is a semiconductor package in which a semiconductor chip 4 is mounted on a portion 2a (hereinafter referred to as a die pad) called a die pad or a tab of a lead frame, and a plurality of pads are arranged on the upper surface of the semiconductor chip 4. After being connected to a plurality of leads 2b arranged on the side surface of the semiconductor chip 4 with a conductive wire 3, the semiconductor chip 4, the conductive wire 3 and the connecting portion thereof are covered with a sealing body 5 made of an insulating resin.

The semiconductor package has only four surfaces in which each lead 2b is in contact with the sealing body 5, and the shape is a simple rectangular parallelepiped shape, and the cross-sectional structure thereof is a quadrangle. Therefore, when the semiconductor package is mounted on the terminal substrate, the lead 2b has an interface peeling on the contact surface between the lead 2b and the sealing body 5 due to the thermal stress on the lead due to the difference in the coefficient of thermal expansion, and the lead 2b There was a problem that it dropped out. Similarly, the die pad 2a also has a problem of falling off from the sealing body 5.

Patent Document 1 introduces a method for manufacturing a semiconductor package for avoiding the influence of heat stress.
FIG. 13 shows a side perspective view (a) and a back view (b) of the Quad Flat Non-Leaded Package (hereinafter referred to as QFN), which is a leadless package described in Patent Document 1, as viewed from the lower surface of the package. It is reprinted. Further, the part A in FIG. 13 is shown in FIG. 14 (a) as an enlarged view of the lead cross-sectional shape of the lead 112b, and the enlarged view of the part B is shown in FIG. 14 (b). The lead 112b has a shape in which the recesses 116 are arranged on the two long sides to increase the adhesive area with the insulating resin and improve the adhesion. The two sides of the lead cross section shown in FIG. 14A on the lower surface side are tapered by pressing, so that the insulating resin 115 flows into the taper 117 of the lead 112b exposed on the lower surface of the package and involves the lead 112b. This prevents the leads from falling off toward the bottom surface of the package. The lead in which FIGS. 14 (a) and 14 (b) are used in combination has a shape as shown in the perspective view shown in FIG. 14 (c), and the contact area between the lead 112b and the insulating resin of the sealing body 115 increases. It is clear that it is doing.

FIG. 15 shows another example of the lead shape by press working to prevent the lead from falling off from the lower surface of the package, which is also described in Document 1. Part A in FIG. 13 is shown in FIG. 15A as an enlarged view of the lead cross-sectional shape of the lead 112b, and part B is shown in FIG. 15B. As shown in FIG. 15A, this is an example in which the lead cross section is T-shaped. The insulating resin of the sealing body 115 flows under the brim portion 119, which is a stepped portion of the lead 112b exposed on the lower surface of the package, and the lead 112b is formed into a shape that wraps around the lead 112b to prevent the lead from falling off from the lower surface of the package. There is. The lead in which FIGS. 15A and 15B are used in combination has a shape as shown in the perspective view shown in FIG. 15C, and the contact area between the lead 112b and the insulating resin of the sealing body 115 increases. It is clear that it is doing.

JP-A-2007-243220

However, in a smaller and thinner semiconductor package, it has been found that the reeds and die pads are likely to fall off from the sealed body due to stress such as thermal stress due to the further narrowing of the lead pitch.

Due to the recess 116 on the side surface of the lead provided in the lead 112b described in Patent Document 1, the adhesion between the insulating resin of the sealing body 115 of the semiconductor package and the lead is improved, but the mounting with the terminal substrate is improved. Since the connection area is small, the connection force after mounting may be reduced, which may lead to a further decrease in connection reliability. When the cross-sectional shape of the reed is T-shaped, a step 119 is formed to prevent the lead from falling off from the insulating resin. Therefore, the X dimension on the step forming side and the exposed width Y dimension of the lead 112b in the side view of FIG. Since the relationship is Y <X and the lead width is narrower than the conventional connection lead width, the mounting connection area on the terminal board becomes small, the connection force after mounting decreases, and the connection reliability may decrease. was there.

The present invention has been made in view of the above problems, and a semiconductor package in which the lead or die pad has good adhesion strength with the insulating resin of the sealant even when the semiconductor package is further miniaturized and thinned. It is an object of the present invention to provide a semiconductor device using the above.

In order to solve the above problems, the following means were used in the present invention.
First, the semiconductor chip mounted on the die pad and
With the reeds arranged apart from each other around the die pad,
A sealant that seals the die pad, the semiconductor chip, and the reed,
Consists of
The back surface of the die pad and the lead is exposed from the sealing body.
The lead has a lead brim portion that is thinner than the lead and is bent in the direction opposite to the back surface of the lead along the side that is the upper end portion of the surface of the lead facing the die pad. The semiconductor device is characterized in that it is provided.

Further, the semiconductor chip placed on the die pad, leads arranged apart from each other around the die pad, and a sealant in which the die pad, the semiconductor chip, and the lead are sealed are composed of the die pad, the semiconductor chip, and the lead. A method for manufacturing a semiconductor device in which the back surface of a die pad and the lead is exposed from the sealing body.
A step of forming the die pad and the lead on the lead frame, and forming a lead brim portion protruding from the surface of the lead frame and having a thickness thinner than the lead on the upper end portion of the lead.
The step of fixing the semiconductor chip on the die pad with an adhesive and
A step of sealing the die pad, the semiconductor chip, and the reed with an insulating resin to form a sealed body, and
The step of cutting the lead frame around the encapsulant to separate it into individual pieces.
The method for manufacturing a semiconductor device is characterized by the above.

By using the above means, even when the semiconductor device is further miniaturized and thinned, the leads and die pads have good adhesion strength with the insulating resin of the sealant, and can be used with the terminal substrate after mounting. It is possible to provide a semiconductor device using a semiconductor package capable of maintaining high quality connection reliability.

It is a side view and the top view of the semiconductor package which is an Example of this invention. It is an enlarged view of the vicinity of the brim part of the semiconductor package which is the Example of this invention. It is a figure which shows the tip shape of the brim part of the semiconductor package which becomes the Example of this invention. It is a figure which shows the shape of the lead overhang part and the lead protrusion part of the brim part of the semiconductor package which is the Example of this invention. It is a figure which shows the protrusion shape of the brim part of the semiconductor package which becomes the Example of this invention. It is a figure which provided the notch and the through hole in the protrusion of the semiconductor package which is the Example of this invention. It is a figure which shows the manufacturing process of the semiconductor package which becomes the Example of this invention. It is a middle diagram of the manufacturing process of the semiconductor package which becomes the Example of this invention. It is a middle diagram of the manufacturing process of the semiconductor package which becomes the Example of this invention. It is a figure which shows the method of forming the lead frame of the semiconductor package which becomes the Example of this invention. It is a figure which shows the method of forming the lead frame of the semiconductor package which becomes the Example of this invention. It is a perspective view of the conventional resin-sealed semiconductor package. It is a side view and the bottom view of the Quad Flat Non-Leaded Package. It is an enlarged view of the part A and part B shown in FIG. It is an enlarged view of the part A and part B shown in FIG.

Hereinafter, a semiconductor package and a method for manufacturing the same will be described with reference to the embodiment of the present invention.

FIG. 1 is a side perspective view and a top perspective view of a semiconductor package according to an embodiment of the present invention. FIG. 1B is a top perspective view of the encapsulant passing through the top surface of the semiconductor package, and FIG. 1A is a side perspective view of FIG. 1B from the AA direction. As shown in FIG. 1B, a die pad 2a is provided for a lead frame made of a thin metal plate, a hanging lead 2c for connecting the die pad to the lead frame frame, and a lead 2b separated from the die pad 2a near the periphery of the die pad. It is provided. The semiconductor chip 4 is mounted on the die pad 2a via an adhesive made of a conductive paste such as silver paste, and a plurality of electrode pads on the semiconductor chip 4 are connected to the internal lead portion 7 of the lead 2b via the conductive wire 3. The sealing body 5 is electrically connected so as to cover the semiconductor chip, the conductive wire, the lead, and the die pad with an insulating resin, but the back surface (lower surface) of the die pad and the lead is sealed. Exposed from body 5.

FIG. 1A is a side perspective view of FIG. 1B from the direction AA. A crushing space 10 is provided between the lead 2b and the die pad 2a, and a surface of the die pad 2a facing the lead 2b is provided above the crushing space 10 so as to project upward from the joint portion between the die pad 2a and the semiconductor chip 4. The pad brim portion 11 projects along the side that becomes the upper end portion. Further, the lead brim portion 12 projects along the upper end portion of the surface of the inner lead portion 7 of the lead 2b facing the die pad 2a so as to project upward from the joint portion between the lead 2b and the conductive wire. In this embodiment, the pad brim portion 11 is provided only in the region facing the lead brim portion 12.

The pad brim portion 11 and the lead brim portion 12 are thin and are formed to be thinner than the thickness of the die pad 2a and the thickness of the lead 2b. The tip of the pad brim portion is bent in the internal direction of the sealing body 5, that is, in the direction opposite to the back surface of the die pad and the lead, and the thermal stress exerted on the die pad 2a is released from the pad brim portion 11 to the sealing body 5 inside the package. It has a structure that makes it possible. Further, the lead brim portion 12 also has a structure in which the thermal stress from the lead 2b is released from the lead brim portion 12 to the sealing body 5 inside the package, similarly to the pad brim portion 11.

Although FIG. 1B shows a structure in which the lead brim portion 12 is arranged only at the tip of the lead 2b facing the die pad 2a, the lead brim portion may be provided on the peripheral edge portion embedded in the sealing body 5. In the illustrated semiconductor package, three surfaces are embedded in the sealing body 5 in a plan view, and by providing the lead brim portion on the three surfaces, the adhesion to the insulating resin is further enhanced.

FIG. 2 is an enlarged view of the vicinity of the brim portion of the semiconductor package according to the embodiment of the present invention.
The pad brim portion 11 is composed of a pad overhang portion 11a and a pad protrusion 11b, and the insulating resin of the sealing body 5 smoothly flows into the lower portion of the pad overhang portion 11a. Since the insulating resin is cured and formed so as to wrap around the pad brim, the structure is such that it does not easily fall off from the insulating resin.

It is well known that stress due to thermal stress or the like causes a large stress at a portion where the cross-sectional shape changes or a portion where the outline changes. Therefore, since the pad protrusion 11b is arranged at the tip of the pad overhang portion 11a and the tip of the pad protrusion 11b faces the inside direction of the insulating resin, the thermal stress from the die pad 2a is pad over from each die pad. It flows to the hang portion 11a, further flows from the pad overhang portion 11a to the pad protrusion 11b, and the maximum stress value is generated at the tip portion. Then, since the stress is released to the inside of the resin of the partial sealing body 5, the relaxation of the thermal stress is promoted, and the interface peeling at the contact surface between the insulating resin and the die pad 2a can be eliminated.

Further, the lead brim portion 12 existing on the lead side is composed of a lead overhang portion 12a and a lead protrusion portion 12b so that the insulating resin of the sealing body 5 flows into the lower portion of the lead overhang portion 12a. Therefore, the insulating resin is hardened and formed so as to wrap around the lead brim portion, so that the insulating resin does not easily fall off from the insulating resin.

It is well known that stress due to thermal stress or the like causes a large stress at a portion where the cross-sectional shape changes or a portion where the outline changes. Therefore, since the lead protrusion 12b is arranged at the tip of the lead overhang portion 12a and the tip of the lead protrusion 12b faces the inside direction of the insulating resin, the thermal stress from the lead 2b is from the lead to the lead overhang portion. It flows to 12a, further flows from the lead overhang portion 12a to the lead protrusion portion 12b, and the maximum stress value is generated at the tip portion. Then, since the stress is released to the inside of the resin of the sealing body 5, the relaxation of the thermal stress is promoted, and the interfacial peeling of the adhesive portion between the insulating resin and the lead 2b can be eliminated.

As described above, by forming the brim portion at the upper end of the die pad and the lead, high quality connection reliability with improved connection resistance against thermal stress is maintained without significantly changing the external dimensions of the semiconductor package. A semiconductor package can be realized. Since the lead frame used in the present invention can be formed by press working, it is a highly productive and inexpensive semiconductor package.

FIG. 3 is a diagram showing the shapes of the pad brim portion and the tip of the lead brim portion of the semiconductor package according to the embodiment of the present invention, that is, the pad protrusion portion 11b and the lead protrusion portion 12b.
FIG. 3A shows a shape in which the protrusion is directed upward of the semiconductor package.

The size 13a of the crushed space portion is determined by the press working size, but as an absolute amount, it depends on the thickness of the lead frame 2. That is, the crushing amount of the lead frame thickness of 100 micrometers used this time was set to 50%, but the actual dimensional value of 13a was 45 micrometers.

FIG. 3B shows a shape in which the protrusion is directed downward of the semiconductor package, which is a comparative example. When the pad protrusion 11b and the lead protrusion 12b are directed toward the lower side of the semiconductor package, the lower dimension 13b of the protrusion is 45 micrometers or less, and the stress due to thermal expansion during mounting and the package are formed by press working from the lead frame. At that time, even if it receives an impact or mechanical stress, a crack is generated, and there is a risk that the lead 2b may fall off. Further, since the opening dimensions 14a and 14b between the two protrusions were substantially the same, the adhesion to the resin and the cured state were good, but the burrs on both protrusions in FIG. 3B were found in the sealing body 5. Since it is exposed, cracks occur even when it receives an impact or mechanical stress, and there is a risk that the lead 2b may fall off.

FIG. 3C shows a shape in which both overhangs on the die pad side and the lead side are bent at a predetermined angle (elevation angle) toward the inside of the sealing body (upper part of the semiconductor package). When the overhang portion of FIG. 3C is formed at an elevation angle of 15 degrees, the dimensional value of 13c is about 130 micrometers, which is the same level as the spatial dimension of the crushed space portion in FIG. 3A, which is sufficient. Strength was obtained.

FIG. 3D shows a shape in which both the overhang portions on the die pad side and the lead side are bent at a predetermined angle (blind angle) toward the outside of the sealing body (lower part of the semiconductor package), which is a comparative example. FIG. 3D shows an example in which the overhang portion has a dip angle of 15 degrees. Both tips of the overhangs are directed toward the lower part of the semiconductor package, a part of the overhangs is exposed from the insulating resin of the sealant 5, and the stresses of both overhangs are concentrated on the lower part of the semiconductor package. Resin cracks occurred in the concentrated area.

As described above, good results were obtained by directing the tips of both brim portions toward the inside of the sealing body 5 of the semiconductor package as shown in FIGS. 3A and 3C.

FIG. 4 is a diagram showing the shapes of the lead overhang portion and the lead protrusion portion of the brim portion of the semiconductor package according to the embodiment of the present invention. Here, the angles of the overhang portions of both brim portions of the pad overhang portion 11a and the lead overhang portion 12a toward the inside of the sealing body 5 of the semiconductor package will be described. Since the principle of avoiding stress concentration due to thermal expansion of the pad brim portion 11 of the die pad 2a and the lead brim portion 12 of the lead 2b is the same principle, only the lead brim portion will be described.

Due to heat, the insulating resin of the sealant 5 expands toward the outside of the package on the left side, that is, toward the lead side. The lead frame in the present invention uses a copper alloy, the coefficient of thermal expansion thereof is 16.7 × 10 ^-6 / ° C., and the insulating resin of the sealant 5 is an epoxy resin and its thermal expansion thereof. Since the coefficient is 45 to 65 × 10 ^-6 / ° C, the relationship is
Since the relationship is that the coefficient of expansion of the lead frame is less than the coefficient of expansion of the insulating resin, strain is generated at the interface between the surface of the lead 2b and the insulating resin due to the expansion difference between the two substances, and interface peeling is likely to occur.

Therefore, as shown in FIG. 4, the resin expansion starts from the inside of the sealing body 5 mounted on the semiconductor chip on the right side at the transformation point P rising from the lead 2b leading to the lead overhang portion 12a, and the inside of the sealing body 5 Since thermal expansion occurs from the lead side to the left side, the stress value is small with respect to the area 16.

Further, since the lead brim portion 12 expands from the P point to the R point toward the upper part of the device, it is considered that compressive stress is generated in the area 17 due to the expansion of the insulating resin, but the lead protrusion portion 12b is the upper part of the package. Since it expands in the direction, the stress of the lead brim portion 12 moves from the pole change point R to the upper part of the sealing body 5 and to the tip of the lead protrusion portion 12b. Therefore, it can be seen that the largest stress is generated at the overhang portion 12a between the polarization point P and the polarization point R.

From this, the lead overhang portion 12a to which the thermal stress is applied can relax the stress concentration of compression and tension at the contact interface between the two substances by having an angle toward the upper part of the sealing body 5 rather than being horizontal. It can help prevent the lead from falling off. Further, the thickness of the insulating resin from the lower surface of the lead 2b of the insulating resin cured so as to involve the polarization point P to the variation point P becomes thicker toward the tip of the lead overhang portion 12a, that is, the variation point R. Therefore, the adhesion strength between the insulating resin and the lead overhang portion 12a becomes strong, and it contributes to stress relaxation with respect to the proof stress of mechanical external stress and thermal stress due to thermal expansion, which is effective as a measure to prevent the lead and die pad from falling off. Is.

The lead frame thickness used in this example was 100 micromate, and the crushed space portion had a depression depth of 45 micromail. Therefore, the overhang 12a has about 300 micrometers to 500 micrometers, and if the elevation angle of the overhang 12a is 15 °, the dimension 15 up to the change point R of the overhang 12a with the lead protrusion 12b. Since the amount of change of 77 micrometers is obtained and the depression depth 13 of the crushed space portion 10 is 45 micrometers, the total thickness is about 120 micrometers. A large stress is also generated at the transition point R connecting the lead overhang portion 12a to the lead protrusion 12b, but by angling the tip of the lead protrusion 12b toward the upper part of the sealing body 5, at the contact interface between the two substances. It is possible to relax the stress concentration of compression and tension.

That is, the tip of the lead protrusion 12b is directed toward the upper part of the sealing body 5, so that the thermal expansion stress of the insulating resin exists as a compressive stress in the area 17, but in the area 18, the tensile stress due to the expansion of the insulating resin. Is present, and the contact surfaces of the insulating resins on both sides and the lead protrusions 12b, which are the same substances, are in a stress equilibrium state, so that the occurrence of interfacial peeling can be prevented.

Further, in the expansion direction due to the thermal influence on the lead protrusion 12b, stress concentration due to the thermal influence occurs inside the sealing body 5, that is, in the area 19 of FIG. 4, but the set length of the lead protrusion 12b is the lead. Since the length is less than 50% of the set length of the overhang portion 12a, the amount of change in thermal expansion is smaller than that of the lead overhang portion 12a, so that it can be judged that the influence on the thermal stress is small.

FIG. 5 is a diagram showing the shape of a protrusion of a brim portion of a semiconductor package according to an embodiment of the present invention. A preferable installation direction of the lead protrusions 11b and 12b will be described with reference to this figure.
As shown above, the installation angle of the lead protrusion 12b is as shown in FIG. 5A in consideration of the expansion direction due to the thermal influence of the insulating resin and the expansion direction due to the thermal influence on the lead protrusion 12b. It can be said that it is preferable to install the lead protrusion 12b in the direction opposite to the surface exposed from the sealing body 5 of 2b, that is, inside the semiconductor package in the vertical direction.

Preferably, at an angle S + 90 degrees of the lead overhang portion 12a of FIG. 4, the tip of the lead protrusion 12b is directed to the side surface of the semiconductor package 1 and the pad protrusion 11b is directed to the die pad as shown in FIG. 5 (b). The shape that faces is good.

Then, a pad overhang 11a portion is formed on the pad brim portion 11 of the die pad 2a with the same structure, and a pad protrusion 11b is further formed at the tip thereof to prevent the die pad from falling off from the sealing body 5 due to the same thermal effect. It becomes possible to prevent. At that time, it is preferable that the tip of the pad protrusion 11b has the shape shown in FIG. 5 (b) toward the upper part of the semiconductor package or toward the semiconductor chip 4.

A comparative example is shown in FIG. 5 (c). The same effect can be obtained even when both the pad protrusion 11b at the tip of the pad brim portion 11 of the die pad 2a and the lead protrusion 12b at the tip of the lead brim portion 12 of the lead 2b are directed toward the lower part of the semiconductor package as shown in FIG. 5C. However, if the crushed space dimension 13 in FIG. 5 (c) is small, burrs at the tips of both protrusions or a part of the protrusions may be exposed, and the same state as in FIG. 3 (b) can be obtained. It cannot be said that it is preferable because of concern.

Based on the above, the pad overhang 11a of the die pad 2a is bent to give an angle S, the lead overhang portion 12a is bent to give an angle S of the lead 2b, and the tips of both overhangs are bent. By bending the pad protrusion 11b and the lead protrusion 12b at an angle of S + 90 degrees at the ends, the lead width exposed to the outside and the connection resistance to thermal stress are not required without major changes to the die pad. It is possible to realize a semiconductor package using an inexpensive lead frame that improves strength and maintains high-quality connection reliability that can prevent leads and die pads from falling off. It is desirable that the angle S is 0 degrees or more and 35 degrees or less with respect to the lower surface of the semiconductor package and the exposed lower surface of the lead 2b.

FIG. 6 is a view in which a notch is provided in a protrusion of a semiconductor package according to an embodiment of the present invention, and a through hole is provided.
By providing a through hole 21 or a notch 20 at the tip of the pad protrusion 11b located at the tip of the pad brim portion 11 of the die pad 2a, the insulating resin of the sealing body 5 flows into the through hole or the notch, which causes a thermal effect. It is possible to prevent the leads and die pads from falling off due to mechanical stress from the outside.

FIG. 6A shows a structure in which a notch 20 is formed on the side surface of the overhang portion. Further, FIG. 6B has a structure in which a notch 20 is formed on the side surface of the overhang portion and a through hole 21 is provided at the tip of the protrusion. By doing so, the adhesive area between the pad brim portion or the lead brim portion and the insulating resin is increased, and the adhesive force between them is improved.
This structure may be applied to either the lead 2b or the die pad 2a, or may be applied to both.

A method of manufacturing a semiconductor package according to an embodiment of the present invention will be described with reference to FIGS. 7 to 11.
FIG. 7 is a diagram showing a manufacturing process of a semiconductor package according to an embodiment of the present invention. 8 and 9 are intermediate views of the manufacturing process of the semiconductor package according to the embodiment of the present invention. In addition, FIGS. 10 and 11 are views showing a method of forming a lead frame.

First, as shown in FIG. 7, in the first step, a thin tape-shaped metal plate such as a copper alloy or a nickel alloy is used as a lead frame material for a semiconductor package, and a mold in which a desired pattern is formed is used. The lead frame 2 is formed by a few shots. In the present invention, the thickness of the lead frame material is 100 micrometers.

The lead frame after being pressed is shown in FIG. (A) is a top view, and (b) is a cross-sectional view taken along the line AA of (a). The lead frame 2 has a die pad 2a and a lead 2b formed inside the surrounding lead frame frame 2d. The leads 2b are formed apart from each other in the vicinity of the die pad 2a, and the adjacent leads 2b are connected by a dam bar 6. Further, the die pad 2a is connected to the lead frame frame 2d by the hanging lead 2c. A crushing space 10 is provided between the die pad 2a and the lead 2b, and a thin pad brim portion 11 is formed at the upper end portion of the die pad 2a and a thin lead brim portion 12 is formed at the upper end portion of the lead 2b so as to project from the surface of the lead frame. Has been done.

The manufacturing method will be described again with reference to FIG. 7. In the second step, the semiconductor chip formed on the wafer in another step is individualized by a dicing method, and the fragmented semiconductor chip is placed on the die pad 2a of the lead frame 2 by using a conductive paste or the like to lead the frame. It is fixed to the die pad 2a of 2.

The third step is a step of ball-bonding the conductive wire to a plurality of individual electrode pads serving as leads of the semiconductor chip 4 and stitch-bonding the conductive wire to the other plurality of internal leads 7. The conductive wire, which is a bonding wire, usually has a diameter of 15 micrometers to 25 micrometers, and 25 micrometers was used in this manufacturing method.

The fourth step is a step of coating with an insulating resin to protect the semiconductor chip, the conductive wire, the internal lead, and the die pad, and is usually sealed in a mold formed into a desired shape.

FIG. 9 shows an intermediate view of the manufacturing process after the fourth process. (A) is a top perspective view, and (b) is a side perspective view of (a) from the AA direction. A semiconductor chip is mounted on a die pad 2a of a lead frame 2 press-processed into a predetermined shape via an adhesive made of a conductive paste such as silver paste, and a plurality of electrode pads on the semiconductor chip are connected via a conductive wire 3. The sealing body 5 is electrically connected to the internal lead portion 7 of the lead 2b, and further, the sealing body 5 is formed so as to seal the semiconductor chip, the conductive wire, the internal lead portion, and the upper surface of the die pad with an insulating resin. ..

The manufacturing method will be described again with reference to FIG. 7. The fifth step is a step called trim foam, which is a step of cutting unnecessary metal (lead frame frame or the like) from the lead frame with a press die to separate the sealed body.
Through the above steps, the semiconductor package according to the embodiment of the present invention as shown in FIG. 1 is completed.

Next, a method of forming the pad brim portion and the lead brim portion will be described with reference to FIGS. 10 and 11. A method of simultaneously forming both the pad brim portion and the lead brim portion will be described with reference to FIG. 10, and a method of forming only the lead brim portion will be described with reference to FIG.

10 (a) and 10 (g) are views showing the first pressing process. After the reed and the portion to be the die pad are formed, the brim portion forming area 10a around the die pad is press-processed by using the first upper die 26 and the first lower die 22 to form the die pad and the lead. A thin part is formed between them. Later, the pad brim portion 11 and the lead brim portion 12 shown in FIG. 8 will be formed in the thin-walled region.

FIG. 10B is a diagram showing a second pressing process. After forming the thin-walled portion, the brim portion forming area 10a is fixed by the second lower mold 24 and the second upper mold 23, and then the thin-walled portion is set to the die pad side and the lead side by the shear blade 25. Divide into and. The lead frame after the mold and the shear blade are retracted from the lead frame are shown in FIGS. 10 (c) and 10 (h). The thin-walled part, which later becomes the brim part, extends horizontally without any change from other parts in the lead frame at this point, and since the thin-walled part is thinly processed and formed, even if it is 45 micrometers thick by work hardening. It can be formed without frequent defects such as lead bending. 11 (a) and 11 (e) correspond to the case where only the lead brim portion is formed, and the lead brim portion is formed from the second pressing step.

FIG. 11 (g) is an enlarged view of the L portion in FIG. 10 (h). The notch 20 and the through hole 21 can be formed by using a round or corrugated shear blade in the second pressing step. Even with such a simple method, it is possible to form notches and through holes in the pad protrusions 11b and the lead protrusions 12b as described in the third embodiment to increase the adhesion area with the insulating resin. .. When only the lead brim portion is formed, FIG. 11 (h) is an enlarged view of the M portion in FIG. 11 (e).

FIG. 10D is a diagram showing a third pressing process. After the die pad 2a and the lead 2b are supported by the press support lower die 28, the press presser upper die 27 is arranged on the upper surface of the overhang portion and the protrusion portion so as to form a desired shape, and then the push-up forming die 29 It is pushed up from the lower surface of the thin-walled parts (which will later become the brim parts) on both sides that extend horizontally at. The corresponding FIG. 11B is a molding method in which only the lead brim portion is formed, and the pad brim portion is unnecessary.

Next, when the push-up forming die 29 is retracted as shown in FIG. 10 (e) and the press support lower die 28 and the press presser upper die 27 are retracted, FIGS. 10 (f) and 10 (i) are drawn. As shown in the above, a pad overhang portion 11a and a pad protrusion 11b are formed on the upper end of the die pad 2a, and a lead overhang portion 12a and a lead protrusion 12b are formed on the upper end of the lead 2b, respectively. When only the lead brim portion is formed, the push-up forming die 29 is retracted as shown in FIG. 11 (c), and when the press support lower die 28 and the press presser upper die 27 are retracted, FIG. 11 (d) and As shown in (f), a lead overhang portion 12a and a lead protrusion portion 12b are formed at the upper end portion of the lead 2b.
As described above, the desired lead frame is completed through the first press step to the third press step.

In the process diagram of FIG. 7, for convenience, the manufacturing process diagram of the semiconductor package including the press working process of the lead frame is used, but in the stage before this process, an etching method for improving the adhesion with the insulating resin is used. The fine perforation and surface roughness treatment used may be applied to the pad brim portion or the lead brim portion partially or the entire surface of the lead frame material. Further, FIG. 7 is a process diagram in which the curing process, the lead plating process, and the like are omitted, and is composed of only the necessary processes. However, it can be seen that the lead frame and the semiconductor package are manufactured only by this process diagram. It does not stipulate. Furthermore, the manufacturing order of each process is not particularly specified.

The present invention contributes to thinning of a semiconductor device using a small leadless type semiconductor package in which a semiconductor chip is sealed with a resin.

1 Semiconductor device (semiconductor package)
2 Lead frame 2a Die pad 2b Lead 2c Die pad hanging lead 2d Lead frame frame 3 Conductive wire 4 Semiconductor chip 5 Encapsulant 6 Dam bar 7 Internal lead part 10 Crushed space part 10a Brim part forming area 11 Pad brim part 11a Pad overhang 11b Pad protrusion Part 12 Lead brim part 12a Lead overhang part 12b Lead protrusion part 13 Crushed space part Dimensions 14a, 14b, 14c, 14d Projection opening size 15 Dimensions up to change point R 16, 17, 18, 19 Area 20 Notch 21 Through hole 22 , 24 Lower die 23, 26 Upper die 25 Shear blade 27 Press presser Upper die 28 Press support Lower die 29 Push-up forming die S angle

Claims (6)

A semiconductor chip mounted on a die pad and
With the reeds arranged apart from each other around the die pad,
A sealant that seals the die pad, the semiconductor chip, and the reed,
Consists of
The back surface of the die pad and the lead is exposed from the sealing body.
The lead has a lead brim portion that is thinner than the lead and is bent in the direction opposite to the back surface of the lead along the side that is the upper end of the surface of the lead facing the die pad. provided Te,
The lead brim portion is composed of a lead overhang portion and a lead protrusion portion, and the semiconductor device is characterized in that the lead overhang portion has a predetermined elevation angle in a sealing body direction opposite to the back surface. .. The semiconductor device according to claim 1, wherein said lead is the protrusion notch or through-hole. At the upper end of the die pad facing the reed, a pad brim portion that is bent in the direction opposite to the back surface and is thinner than the thickness of the die pad is formed on the upper end of the surface of the die pad facing the lead. The semiconductor device according to claim 1 or 2 , wherein the semiconductor device is provided in a region facing the lead brim portion along a side that is a portion. The claim is characterized in that the pad brim portion includes a pad overhang portion and a pad protrusion portion, and the pad overhang portion has a predetermined elevation angle in a sealing body direction opposite to the back surface. 3. The semiconductor device according to 3 . The semiconductor device according to claim 4, wherein the pad protrusion is provided with a notch or a through hole. The semiconductor device according to claim 1 or 4, wherein the predetermined elevation angle is 0 to 35 degrees with respect to the back surface.

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