JP2003017628A - Resin-sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optimal resin-sealed semiconductor device by considering respective characteristics which are in a relation of trade-off. SOLUTION: A first crank 2c-1 and a second crank 2c-2 are formed on a second lead 2 side. The crank 2c-1 is formed inside a resin sealing part 4, and the crank 2c-2 is formed outside a second lead 2 exposed from the side of the part 4. By this configuration, chipping of the corners of the part 4 is prevented, heat dissipating characteristics and moisture-resistance are improved, and current capacity is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved structure of a particularly small resin-sealed semiconductor device which can be surface-mounted on an electronic circuit board or the like.

[0002]

2. Description of the Related Art A structural example of a conventional resin-sealed semiconductor device of this type is shown in FIGS. In the resin-encapsulated semiconductor device of FIG. 8, the rising portion 1c of the first lead 1 and the similar rising portion 2c of the second lead 2 bent in a crank shape are exposed to the outside from the side surface of the resin-sealing portion 4, and , The first lead 1
The lower surface of the outer end 1b and the lower surface of the outer end 2b of the second lead 2 are formed so as to be flush with the lower surface of the resin sealing portion 4. Further, the semiconductor pellet 3 is fixed on the inner end 1a of the first lead 1, and a fine wire 5 is used between the surface electrode (not shown) of the semiconductor pellet 3 and the inner end 2a of the second lead 2. It is connected by bonding.

In the resin-sealed type semiconductor device of FIG. 9, a part of the outer end 1b of the first lead 1 and a rising part 1c continuous with the part are embedded in the resin-sealed part 4. A part of the outer end 1b is exposed on the bottom surface of the resin sealing portion 4. The configuration of the second lead 2 and other configurations are similar to those of the resin-encapsulated semiconductor device of FIG. 8, and thus the same reference numerals are given and the description thereof is omitted.

In the resin-sealed semiconductor device shown in FIG. 10, the semiconductor pellet 3 is soldered and fixed so as to sandwich the semiconductor pellet 3 between the inner ends 1a, 2a of the first lead 1 and the second lead 2. A part of the outer ends 1b, 2b of the second lead 2 and the rising portions 1c, 2c continuous with the part are both embedded in the resin sealing portion 4.

The resin-encapsulated semiconductor device of FIG. 11 was previously filed by the applicant as Japanese Patent Application No. 2000-112781. That is, this resin-sealed semiconductor device is
The rising portion 2c of the second lead 2 is not buried in the resin sealing portion 4 but is exposed to the outside.

[0006]

In the resin-sealed semiconductor device of FIG. 8, the outer end 1b of the first lead 1 and the second lead 2 are formed.
Creeping distance Lc between the outer ends 2b of the
(The portion shown by the thick line in FIG. 8 is the length corresponding to the creepage distance.)
Can be taken for a relatively long time. However, there is a problem to be solved in terms of how to meet the demand for further miniaturization of this type of device.

Since the rising portion 1c of the first lead 1 and the rising portion 2c of the second lead 2 are exposed to the outside from the side surface of the resin sealing portion 4, the semiconductor pellet 3 is formed.
There was a problem to be solved in that the thermal resistance generated during the operation of was increased by the length.

Further, since the surface of the semiconductor pellet 3 and the inner end 2a of the second lead 2 are bonded by the fine wire 5, the heat radiation from the upper surface of the semiconductor pellet 3 is poor, and the current that can be passed through the semiconductor pellet 3 is low. There was also a problem to be solved that the size could not be increased. Detailed consideration of heat dissipation in the resin-sealed semiconductor device of FIGS. 8 to 11 will be described later.

In the resin-encapsulated semiconductor device of FIG. 9, since the rising portion 1c of the first lead 1 is buried in the resin-encapsulated portion 4, heat dissipation is better than that of FIG. However, in other respects, there was a problem to be solved similar to the above.

In the resin-sealed semiconductor device of FIG. 10, the first
Rise 1c of lead 1 and rise 2c of second lead 2
Since the and are embedded in the resin sealing portion 4, the creepage distance Lc between the leads 1 and 2 is particularly small, and it is difficult to cope with a semiconductor device having a large reverse voltage. This type of resin-encapsulated semiconductor device has been further miniaturized in order to meet the demands for miniaturization of electronic circuit boards and high-density mounting, and the outer shape is about 4 mm in the longitudinal direction. Has become. Therefore, the creepage distance Lc is also relatively small, and in order to obtain a reverse breakdown voltage of 400 V or more, how to increase the creepage distance Lc is an issue in the demand for miniaturization. By the way, UL standard 400V / 2mm
The creepage distance Lc is calculated.

In the resin-sealed semiconductor device of FIG. 11, the second
Since the rising portion 2c of the lead 2 is exposed to the outside from the side surface of the resin sealing portion 4, the creepage distance Lc is moderately set, and the semiconductor pellet 3 and the inner end 2a of the second lead 2 use a thin wire. Since it is directly fixed through the convex portion 2d without being formed, the heat dissipation is also good. However, when forming the crank-shaped rising portion 2c, the resin-sealed portion 4 starts from the crank-shaped bending start point.
Since the height h1 to the top surface of the resin is extremely thin (for example, h1 = 0.10 to 0.15 mm), mechanical stress is applied to the resin sealing portion 4 such as cracks or defects. It has been found that there is a risk that the electric characteristics of the semiconductor device are deteriorated.

Next, the thermal resistance of the resin-sealed semiconductor device having the structure shown in FIGS. 8 to 11 is calculated, and the results of the three-dimensional simulation are shown in FIGS. 12 to 15. Note that FIG. 12 is FIG. 8, FIG. 13 is FIG. 9, FIG. 14 is FIG. 10, and FIG. 15 is FIG. 11, which are results of three-dimensional simulation of a resin-sealed semiconductor device having a corresponding structure. is there. The outline of specific setting conditions is as follows.

Number of dividing elements: Approximately 2400 (Because it is symmetrical with respect to the center line of the resin-sealed semiconductor device in the longitudinal direction, only half the region in the longitudinal direction is calculated.) Dimension of semiconductor pellet: 1 .05 □ × 0.28t (m
m) Power consumption: 1.0 (W) Power density: 3.24 (W / cm3) Heat dissipation coefficient of outer surface: 1.0E-4 (W / cm2) Room temperature: 25 ° C Thermal conductivity (W / mm ・C): Si (84E-3), C
u (386.4E-3), solder 35.1E-3), mold resin (7E-4) of resin encapsulation part Under the above conditions, 1 W is applied to the resin-encapsulated semiconductor device of each structure.
It is a steady-state three-dimensional heat distribution simulation in which how many times the temperature of each part rises when a power of (1 A × 1 V) is continuously applied. In each figure, T1 has the highest temperature and T10 has the lowest temperature. That is, the temperature gradient is shown as an isotherm slope, T1>T2>T3> T4.
>T5>T6>T7>T8>T9> T10.

The actual numerical examples in FIG. 12 are as follows. T1 = 74.940 ° C., T2 = 69.37
5 ° C, T3 = 63.809 ° C, T4 = 58.244 ° C,
T5 = 52.678 ° C., T6 = 47.113 ° C., T7 =
41.547 ° C., T8 = 35.982 ° C., T9 = 30.
416 ° C., T10 = 24.851 ° C. Therefore, the thermal resistance (Rth) is Rth = T1−T10≈50 ° C./W.

Similarly, Rth of the resin-sealed semiconductor device having the structure of FIG. 13 is T1 = 50.811 ° C., T10.
= 24.948 ° C, Rth≈26 ° C / W. Similarly, Rth of the resin-sealed semiconductor device having the structure of FIG. 14 is T1 = 38.323 ° C., T10 = 25.
Since it is 000 ° C., Rth≈13 ° C./W. Similarly, the Rt of the resin-sealed semiconductor device having the structure of FIG.
h is T1 = 40.956 ° C, T10 = 24.983 ° C
Therefore, Rth≈16 ° C./W.

In addition, the isotherm slope α (° C /
If div) is shown, it is as follows. 12 (FIG. 8), α = 5.565, FIG. 13 (FIG. 9), α = 2.873, FIG. 14 (FIG. 10),
α = 1.480, in the case of FIG. 15 (FIG. 11), α = 1.
It was 594.

Further, as a result of the above three-dimensional heat distribution simulation, the features of the heat distribution will be shown as follows. In the structure of FIG. 12 (FIG. 8), the semiconductor pellet 3 and the second
Since the lead 2 is connected by the thin wire 5,
The heat transfer to the lead 2 is small, and the isotherm slope between the first lead 1 and the second lead 2 is large. Further, the heat radiation from the first lead 1 is relatively small. The temperature distribution of T1 which is the maximum reached temperature is also wide.

In the structure of FIG. 13 (FIG. 9), the structure of FIG.
Similar to the structure of FIG. 8, the semiconductor pellet 3 and the second
Since the lead 2 is connected by the thin wire 5,
The heat transfer to the lead 2 is small, and the isotherm slope between the first lead 1 and the second lead 2 is also large. However, since a part of the outer end 1b of the first lead 1 and the rising portion 1c continuous with the outer end 1b are embedded in the resin sealing portion 4 and the heat transfer distance from the semiconductor pellet 3 is shortened, the first lead 1 The heat dissipation of No. 1 is good. The heat radiation effect from the first lead 1 contributes to narrow the temperature distribution range of T1 which is the maximum reached temperature.

In the structure shown in FIG. 14 (FIG. 10), since the semiconductor pellet 3 is directly soldered to the inner end 2a of the second lead 2, heat transfer to the second lead 2 is large. Further, the disturbance of the isotherm slope between the first lead 1 and the second lead 2 is small, and the heat radiation from both leads 1 and 2 is good. Furthermore, the method of fixing the semiconductor pellets 3 and the effect of radiating heat from the second leads 2 have been added to provide a substantially even heat distribution on the left and right.

In the structure shown in FIG. 15 (FIG. 11), the semiconductor pellet 3 is directly soldered to the inner end 2a of the second lead 2 in the same manner as described above.
Since the distance from to the outer end 2b of the second lead 2 becomes relatively long, the temperature distribution range of T1 which is the maximum reached temperature is shifted to the second lead 2 side. Further, the temperature distribution range of T3 on the quasi-high temperature side is expanded to the second lead side, and the heat radiation effect from the second lead 2 is reduced.

Next, comparing the creepage distance Lc in each structure, FIG. 12 (FIG. 8)> FIG. 15 (FIG. 11)> FIG.
3 (FIG. 9)> FIG. 14 (FIG. 10). Also, in terms of current capacity, the structures of FIG. 12 (FIG. 8) and FIG. 13 (FIG. 9) are not sufficient in heat dissipation characteristics, so that the electric capacity is limited. On the other hand, in the structure of FIG. 14 (FIG. 10), the creepage distance Lc is the shortest, so there is a risk of a short circuit during bottom surface reflow. Further, in the structure of FIG. 15 (FIG. 11), as described above, the height h1 to the top surface of the resin sealing portion 4 is low and the resin sealing portion 4 is easily damaged during the forming process. Forming is difficult because the height h2 to the bottom surface (see FIG. 11) is high. In this way, there is a trade-off relationship between the characteristics such as thermal resistance, creepage distance, and current capacity in each structure.
A major problem to be solved is how to optimize those characteristics and realize them in an extremely small device having a total length of 4 mm or less.

[0022]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and improves the heat dissipation characteristics, increases the creepage distance, and secures the height h1 to the top surface of the resin sealing portion.
Ensuring ease of lead forming processing, sufficient tensile strength in the longitudinal direction of the second lead, lengthening the moisture entry path to the semiconductor pellet as much as possible to improve moisture resistance, and between the leads within the resin encapsulation part Optimum resin at the present time in consideration of securing suitable shape for dielectric strength, consideration of heat distribution and stress inside resin encapsulation, simplicity of assembly process and reduction of total cost. It is an object to provide a sealed semiconductor device.

[0023]

According to another aspect of the present invention, there is provided a resin-encapsulated semiconductor device, wherein a semiconductor pellet is fixed between opposing surfaces of inner ends of a first lead and a second lead. In a resin-sealed semiconductor device in which the periphery of one end is sealed with resin to form a resin-sealed portion, the lower surface of the outer end of the first lead is flush with the lower surface of the resin-sealed portion. And, a part of the outer end exposes only its lower surface to the lower surface of the resin sealing portion, and a rising part continuous with a part of the outer end is embedded in the resin sealing portion, An inner end continuous to the rising portion is fixed to the semiconductor pellet, a surface of the semiconductor pellet and an inner end of the second lead are fixed, and the second lead is continuous from the inner end. The first claw bent downward at a predetermined angle and embedded in the resin sealing portion. Links and bend folded by a predetermined angle inclined downward continuously with the first crank and a second crank which is exposed to the resin sealing portion outside the second
The flat portion at the outer end of the lead is formed so as to be flush with the lower surface of the resin sealing portion.

In the resin-encapsulated semiconductor device of the second invention, the first lead and the second lead are formed of a plate material, and the plate thickness t1 of the first lead is relatively greater than the plate material t2 of the second lead. It is characterized in that it is formed so as to be thick so that t1> t2.

In the resin-sealed semiconductor device of the third invention, the plate thickness t1 of the first lead is t1 = 0.10 to 0.16.
mm, and the plate thickness t2 of the second lead
Is in the range of t2 = 0.10-0.12.

In the resin-sealed semiconductor device of the fourth invention,
The length L2 of a part of the outer end of the first lead exposed on the lower surface of the resin sealing portion is in the range of L2 = 0.35 to 0.45 mm.

In the resin-encapsulated semiconductor device of the fifth invention, the center position of the semiconductor pellet fixed to the inner end of the first lead is set to be greater than the center position of the resin-sealed portion in the longitudinal direction. It is characterized by being unevenly distributed on the second lead side.

In the resin-sealed semiconductor device of the sixth invention, when the height from the bottom surface to the top surface of the resin-sealed portion is H, from the second crank upper surface to the top surface of the second lead. It is characterized in that the height h1 thereof is within the range of h1 ≧ 0.5H.

[0029]

In the resin-sealed semiconductor device of the first invention, the first
A part of the outer end of the lead is embedded in the resin encapsulation portion, the bottom surface of the part is exposed to the outside so as to be flush with the bottom surface of the resin encapsulation portion, and the inner end of the second lead is formed. Is directly connected to the surface electrode of the semiconductor pellet, the first crank which is continuous with the inner end and is inclined obliquely is embedded in the resin sealing portion, and exposed to the outside from the side surface of the resin sealing portion,
Further, the second crank inclined further downward is formed so that the outer end of the second lead is flush with the bottom surface of the resin sealing portion.

Therefore, the height h1 from the bending start point of the second crank, which is exposed from the side surface of the resin seal portion of the second lead, to the top surface of the resin seal portion can be made relatively larger than in the prior art. Therefore, it is possible to prevent the corner angle of the resin-sealed portion from being damaged during the forming process. A part of the outer end on the second lead side is not embedded in the resin sealing portion, and its bottom surface is also not exposed to the bottom surface side of the resin sealing portion. Therefore, the creepage distance between the first lead and the second lead is reduced. Can be secured for a while. Since the second crank is formed, the height h2 from the second crank bending start point exposed to the outside from the side surface of the resin sealing portion to the bottom surface of the resin sealing portion can be suppressed to a low level.
Since the mounting state is stable and the length from the semiconductor pellet is shortened, the heat dissipation effect is improved. By bending a portion of the second lead, which is continuous with the inner end, downward in the resin-sealed portion to form the first crank, the length of the moisture entry path of the second lead reaching the side surface of the resin-sealed portion is reduced. Since it becomes longer, the moisture resistance is improved. The shortest distance between the bending position of the first crank embedded in the resin sealing portion and the end position of the inner end of the first lead is set to be approximately equal to the inner end distance of the first lead and the second lead sandwiching the semiconductor pellet. Therefore, the shape suitable for maintaining the internal dielectric strength can be secured.

In the resin-sealed semiconductor device of the second invention,
The first lead and the second lead are formed of a plate material, and the plate thickness t1 of the first lead is formed to be relatively thicker than the plate material t2 of the second lead so that t1> t2. The heat distribution is further promoted, and the heat distribution characteristics can be balanced with the heat dissipation on the second lead side.

In the resin-sealed semiconductor device of the third invention,
The plate thickness t1 of the first lead is t1 = 0.10 to 0.16 m
m, and the plate thickness t2 of the second lead is t2
Since the range of 0.10 to 0.12 is set, if both plate thicknesses are selected in such a range, further promotion of heat radiation from the first lead can be surely expected, and heat distribution of the semiconductor device can be expected. A balance can be secured.

In the resin-encapsulated semiconductor device of the fourth invention, the length L2 of a part of the outer end of the first lead exposed on the lower surface of the resin-encapsulated portion is L2 = 0.35-0. Since it is set in the range of 0.45 mm, heat dissipation is surely promoted through an external member such as a substrate that comes into contact with the exposed surface in the range.

In the resin-sealed semiconductor device of the fifth invention,
Since the center position of the semiconductor pellet fixed to the inner end of the first lead is arranged more eccentrically to the second lead side than the center position of the resin sealing portion in the longitudinal direction, the heat dissipation characteristics are improved and the heat distribution characteristics are improved. Can contribute to the equilibrium of.

In the resin-sealed semiconductor device of the sixth invention,
When the height from the bottom surface to the top surface of the resin sealing portion is H,
Since the height h1 from the upper surface of the second crank to the top surface of the second lead is set in the range of h1 ≧ 0.5H, the required strength of the corner angle of the resin-sealed portion against forming process or other external force. It is possible to secure the required height h2 from the bottom surface of the resin sealing portion to the lower surface of the second crank, and to secure the required creepage distance while making a compromise in the drape-off relationship.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
It will be described with reference to the drawings. FIG. 1 is a vertical sectional view of a resin-sealed semiconductor device of the present invention. In the figure, in a resin-sealed semiconductor device 10, a semiconductor pellet 3 is fixed between opposing surfaces of inner ends 1a, 2a of a first lead 1 and a second lead 2, and the semiconductor pellet 3 and the inner end 1a are fixed. , 2a are sealed with resin to form a predetermined resin sealing portion 4.

In the resin-sealed semiconductor device 10 described above, the lower surface of the outer end 1b of the first lead 1 has the resin-sealed portion 4
Is formed so as to be flush with the lower surface of the resin, and a part of the outer end 1b is formed so that only the lower surface is exposed to the lower surface of the resin sealing portion 4. Further, the rising portion 1c which is continuous with a part of the outer end 1b is embedded in the resin sealing portion 4, and
An inner end 1a continuous with the rising portion 1c is horizontally bent, and the semiconductor pellet 3 is placed on the horizontal inner end 1a.
Is placed and fixed by soldering.

On the other hand, the surface electrode (not shown) of the semiconductor pellet 3 and the inner end 2a of the second lead 2 are fixed by soldering,
The second lead 2 is continuously bent from the inner end 2 a thereof and is bent downward at a predetermined angle, and the resin sealing portion 4 is provided.
A first crank 2c-1 buried inside is formed. A second crank 2c-2 is formed at a position where the second crank 2c-1 is bent downward at a predetermined angle and is continuous with the first crank 2c-1, and is exposed to the outside of the resin sealing portion 4, and
The flat portion of the outer end 2b of the second lead is formed so as to be flush with the lower surface of the resin sealing portion 4.

With the above-mentioned structure, the following effects can be obtained. The second crank 2 exposed to the outside from the side surface of the resin sealing portion 4
The height h1 from the bending start point of c-2 to the top surface of the resin-sealed portion 4 can be made relatively large, especially compared with the resin-sealed semiconductor device having the structure shown in FIG. It is possible to effectively prevent the occurrence of cracks and cracks in the corners of the resin-sealed portion 4 at this time. A part of the outer end 2b on the second lead 2 side is provided with the resin sealing portion 4
The first lead 1 and the second lead 2 are not embedded in the inside and the bottom surface thereof is not exposed to the bottom surface side of the resin sealing portion 4.
The creepage distance Lc between them can be secured to the required limit. Since the second crank 2c-2 is formed, the height h2 from the bending start point at the position exposed to the outside from the side surface of the resin sealing portion 4 to the bottom surface of the resin sealing portion 4 can be suppressed to a low level. Since the mounting state of the static semiconductor device 10 is stable and the length from the semiconductor pellet 3 is shortened, the heat dissipation effect is improved. The second lead reaching the side surface of the resin sealing portion 4 is formed by bending the portion of the second lead 2 that is continuous with the inner end 2a once downward in the resin sealing portion 4 to form the first crank 2c-1. Since the moisture penetration path length of 2 can be lengthened, the moisture resistance is improved.

[0040]

EXAMPLES Examples of the above invention will be described below. (1) When the dimensions of the resin-sealed portion 4 of the resin-sealed semiconductor device 10 are length (L) × width (W) × height (H), 2.
It is 3 × 1.6 × 1.0 (mm). (2) The plate thickness t1 of the first lead 1 is t1 = 0.10-0.
-It is 16 (mm). (3) The length L1 of the outer end 1b exposed from the resin sealing portion 4 of the first lead 1 is about L1 = 0.25 to 0.35 mm.

(4) The length L2 of the portion which is continuous with the outer end 1b and is embedded in the resin sealing portion 4 and whose bottom surface is exposed so as to be the same as the bottom surface of the resin sealing portion 4 is L2 = 0. .35-0.
It is 45 mm. (5) The dimension e1 from the lower surface of the inner end 1a of the first lead 1 on which the semiconductor pellet 3 is placed and fixed to the bottom surface of the resin sealing portion 4 is about e1 = 0.14 to 0.18 mm. (6) The center position of the semiconductor pellet 3 placed on the inner end 1a of the first lead 1 is slightly closer to the second lead 2 side than the position of half L / 2 of the length L of the resin sealing portion 4. Is unevenly distributed.

(7) The plate thickness t2 of the second lead 2 is t2 =
The range is 0.10 to 0.12 mm. (8) A convex portion 2d is formed on a side of the inner end 2a of the second lead 2 facing the surface of the semiconductor pellet 3, and the convex portion 2d is formed.
And the surface electrode (not shown) of the semiconductor pellet 3 is fixed by soldering. (9) The distance e2 between the surface side of the inner end 2a of the second lead 2 and the top surface of the resin sealing portion 4 is e2 = 0.14 to 0.18.
mm.

(10) The height h1 from the bending start point of the second crank 2c-2 exposed from the side surface of the resin sealing portion 4 of the second lead 2 to the top surface of the resin sealing portion 4 is h1 ≧
It is 0.5H. Here, H is the height of the resin sealing portion 4,
H = 1 mm. (11) The height h2 from the bending start point of the second crank 2c-2 to the bottom surface of the resin sealing portion 4 is h2 = 0.29 to
It is 0.33H. (12) The length R1 of the flat outer end 2b exposed from the side surface of the resin sealing portion 4 of the second lead 2 is R1 = 0.85-0.
The range is 95 mm. (13) The length R2 from the side surface of the resin sealing portion 4 to the end point of the second crank 2c-2 is R2 = 0.50 to 0.70 m.
The range is m.

Next, the thermal resistance of the resin-encapsulated semiconductor device of the present invention manufactured under the above conditions was calculated,
A three-dimensional simulation of the results is shown in FIG. It should be noted that FIG. 3 is a mesh division diagram in which the number of division elements is about 2400 when calculating the above-mentioned thermal resistance.
As can be seen from FIG. 2, the heat distribution characteristic is significantly improved. That is, as compared with the structure of FIG. 15 (FIG. 11), the range of the maximum reached temperature T1 is reduced, and the T3 region as the quasi-high temperature portion is also improved. The heat radiation from the second lead 2 side is also improved. Also, although slightly to the right of the one in FIG. 15 (FIG. 11), the heat distribution approaches the structure in FIG. 14 (FIG. 10) and has a substantially uniform heat distribution. Therefore, there is no problem in terms of thermal stress.

According to the above embodiments, the thermal resistance (Rth)
= 13.7 ° C./W, the maximum reached temperature is 38.68 ° C., and the isotherm slope is 1.520 ° C./div. The creepage distance Lc is Lc = 2.24 mm. As described above, the present invention improves the heat dissipation characteristics and the heat distribution as compared with the conventional structure.
We have secured the maximum creeping distance and the avoidance of loss of the corner angle of the resin encapsulation in a trade-off relationship.

Next, a method of manufacturing the resin-sealed semiconductor device will be described. As shown in FIG. 4, a series of cathode frames 1 is used to manufacture the resin-sealed semiconductor device of the present invention.
1 and the anode frame 21 are used. The cathode frame 11 is made of a copper (Cu) material, and has a plate thickness of, for example, 0.
The first lead 1 is formed by a machine such as a press using a 15 mm one. That is, the first lead 1 has an inner end 1a, a rising portion 1c, and an outer end 1b, and the first leads 1 are arranged so as to face each other with the connecting portion 6 interposed therebetween, and a plurality of them are formed so as to form a pair. . These first leads 1 are
The cathode frame 11 has a shape extending from the main body connecting portion 12 in a right angle direction. The body connecting portion 12
The guide holes 13 are formed at regular intervals.

A copper (Cu) material is used for the anode frame 21 similarly to the cathode frame 11, but the plate thickness is thinner than the cathode frame 11, for example, a plate thickness of 0.10 mm is used, and the second lead 2 is It is formed by a machine such as a press. That is, the second lead 2 has an inner end 2 a, a rising portion 2 c, and an outer end 2 b, and the second lead 2 is sandwiched by the connecting portion 7.
The leads 2 are arranged so as to face each other, and a plurality of leads 2 are formed so as to form a pair. Many of these second leads 2 extend from the main body connecting portion 22 of the anode frame 21 in the perpendicular direction. Similar to the cathode frame 11, the body connecting portion 22 has guide holes 23 formed at regular intervals.

The solder paste is applied on the inner end 1a of the first lead 1 in the cathode frame 11, the semiconductor pellet 3 is placed thereon, and the solder paste is applied thereon.

A convex portion 2d is formed on the lower surface of the center of the inner end 2a of the second lead 2, and the cathode frame 11 is opposed to the surface electrode (not shown) of the semiconductor pellet 3.
And the anode frame 21 are overlapped. At that time, a guide pin (not shown) is inserted between the guide hole 13 of the cathode frame 11 and the guide hole 23 of the anode frame 21 to position them, and the convex portion 2d of the second lead 2 is placed on the upper surface of the semiconductor pellet 3. Set so that they face each other securely. Then, the semiconductor pellet 3 is soldered and fixed between the first lead 1 and the second lead 2 through a process such as reflow.

Next, the cathode frame 11 and the anode frame 21 are housed in a mold (not shown), resin molding is performed, and the resin sealing portion 4 is shown as shown by the hatched lines in FIG.
To form. FIG. 6 is a sectional view taken along the line AA in FIG. In this state, the first crank 2 of the second lead 2
Only c-1 is formed in the resin sealing portion 4, and from the portion following the first crank 2c-1 to the horizontal outer end 2b,
The side surface of the resin sealing portion 4 is horizontally led out to the outside.

Next, the frames 11 and 21 are housed in a forming die and subjected to a forming process to form a second crank 2c-2 inclined at a predetermined angle on the second lead 2 exposed from the side surface of the resin sealing portion 4. Form. After that, the connecting portions 6 and 7 and the main body connecting portions 12 and 22 are cut by a press or the like, and the individual resin-sealed semiconductor device 1 as shown in FIG.
Get 0.

The cathode lead frame 11 described above is used.
The reason for changing the plate thickness of the anode lead frame 21 is that the thickness of the first lead 1 is finally made larger than the plate thickness of the second lead 2 so that the thermal resistance generated during the operation of the semiconductor pellet 3 is increased. This is because it is transmitted to the first lead 1 side near the electronic circuit board (not shown), and as a result, the current capacity can be increased.

Therefore, if the increase in the current capacity is not particularly expected as compared with the conventional structure, and the other characteristics, for example, prevention of chipping of the corners of the resin-sealed portion 4 are emphasized, the plate thickness is the same. However, the object of the present invention can be sufficiently achieved.

[0054]

Since the resin-encapsulated semiconductor device of the present invention is constructed as described above, it has the following effects. (1) Since the second crank of the second lead exposed to the outside from the side surface of the resin sealing portion is formed, the creeping distance Lc between the first lead and the second lead can be increased. (2) The degree of mechanical stress applied to the corners of the resin-sealed portion during the forming process of the second crank is small, and there is no possibility of causing defects or cracks in the resin-sealed portion. (3) The pressing force during forming of the second crank is
Since it is relatively small as compared with the conventional one, the mechanical stress applied to the semiconductor pellet is small and the electrical characteristics of the semiconductor device are not adversely affected. (4) By forming the second crank, the height h2 from the rear surface of the crank start point to the bottom surface of the resin-sealed portion can be suppressed to a low level, and when mounting the resin-sealed semiconductor device on an electronic circuit board or the like. The placement state can be stabilized. (5) Excellent heat dissipation compared to the conventional one in which the semiconductor pellet is bonded to the second lead with a thin wire,
Moreover, when the plate thickness of the first lead is made thicker than the plate thickness of the second lead, the thermal resistance generated during the operation of the semiconductor pellet is dispersed on the side of the first lead close to the electronic circuit board, so that the current The capacity can be increased. (6) Both the first lead and the second lead are bent portions (starting portion, first crank) that are inclined at a predetermined angle inside the resin sealing portion.
Are formed, and the length of the moisture invasion path can be lengthened, so that the moisture resistance can be improved. (7) Since the external shapes of the first lead and the second lead are different, it is possible to easily determine the polarities corresponding to the different shapes. (8) Since the first crank of the second lead is embedded inside the resin sealing portion, it is possible to sufficiently secure the tensile strength of the second lead in the longitudinal direction. (9) The shape is suitable for the withstand voltage between the leads in the resin-sealed portion, and the heat distribution state and stress inside the resin-sealed portion are sufficiently taken into consideration. (10) The resin-encapsulated semiconductor device is the most suitable at the present time in consideration of the simplicity of the assembling process and the reduction of the total cost, and the trade-off relationship of each element.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a resin-encapsulated semiconductor device of the present invention.

FIG. 2 is a display diagram showing a result of three-dimensional simulation by calculating thermal resistance characteristics of the resin-encapsulated semiconductor device of the present invention.

FIG. 3 is a mesh division diagram when the above three-dimensional simulation is performed.

FIG. 4 is a perspective view showing each component for explaining the manufacturing process of the resin-encapsulated semiconductor device of the present invention.

FIG. 5 is a plan view showing a state in which an anode frame and a cathode frame are combined with a semiconductor pellet sandwiched in the manufacturing process.

6 is a cross-sectional view taken along the line AA in FIG.

FIG. 7 is a vertical sectional view of a resin-encapsulated semiconductor device of the present invention finally obtained through the above manufacturing steps.

FIG. 8 is a vertical cross-sectional view showing a conventional resin-encapsulated semiconductor device.

FIG. 9 is a vertical cross-sectional view showing a conventional resin-sealed semiconductor device.

FIG. 10 is a vertical cross-sectional view showing a conventional resin-encapsulated semiconductor device.

FIG. 11 is a vertical sectional view showing a conventional resin-sealed semiconductor device.

FIG. 12 is a display diagram showing a result of three-dimensional simulation by calculating thermal resistance characteristics of the resin-encapsulated semiconductor device of FIG.

FIG. 13 is a display diagram showing a result of three-dimensional simulation by calculating thermal resistance characteristics of the resin-encapsulated semiconductor device of FIG.

FIG. 14 is a display diagram showing a result of three-dimensional simulation by calculating thermal resistance characteristics of the resin-encapsulated semiconductor device of FIG.

FIG. 15 is a display diagram showing a result of three-dimensional simulation by calculating thermal resistance characteristics of the resin-encapsulated semiconductor device of FIG.

[Explanation of symbols]

1st lead 1a inner edge 1b outer edge 1c Rising part 2 second lead 2a inner edge 2b outer edge 2c Rising part 2c-1 1st crank 2c-2 2nd crank 2d convex part 3 Semiconductor pellet 4 Resin sealing part 5 fine wire 6 connection 7 connection 10 Resin-sealed semiconductor device 11 Cathode frame 12 Body connection part 13 Guide hole 21 Anode frame 22 Body connection part 23 Guide hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiyasu Yokosu             1204 Soya, Hadano City, Kanagawa Prefecture Japan Inter             -Inside the corporation (72) Inventor Takao Senda             1204 Soya, Hadano City, Kanagawa Prefecture Japan Inter             -Inside the corporation (72) Inventor Tsuchiya Showa             1204 Soya, Hadano City, Kanagawa Prefecture Japan Inter             -Inside the corporation (72) Inventor Atsushi Ochiya             1204 Soya, Hadano City, Kanagawa Prefecture Japan Inter             -Inside the corporation F-term (reference) 4M109 AA01 BA01 FA01

Claims (6)

[Claims] 1. A semiconductor pellet is fixed between opposing surfaces of inner ends of a first lead and a second lead, and the periphery of the semiconductor pellet and the inner end is sealed with a resin, and a resin sealing portion is provided. In the formed resin-encapsulated semiconductor device, the lower surface of the outer end of the first lead is flush with the lower surface of the resin-encapsulation portion, and a part of the outer end has only the lower surface of the resin. Exposed on the lower surface of the encapsulation portion, a rising portion continuous with a part of the outer end is embedded in the resin sealing portion, an inner end continuous with the rising portion is fixed to the semiconductor pellet, The surface of the semiconductor pellet and the inner end of the second lead are fixed to each other, and the second lead is continuously bent downward from the inner end at a predetermined angle and is bent by the resin. A first crank embedded in the section, and a downward inclination of a predetermined angle continuously from the first crank. A second crank that is obliquely bent and is exposed to the outside of the resin sealing portion, and a flat portion of the outer end of the second lead is flush with the lower surface of the resin sealing portion. 1. A resin-encapsulated semiconductor device, which is formed in. 2. The first lead and the second lead are formed of a plate material, and the plate thickness t1 of the first lead is formed to be relatively thicker than the plate material t2 of the second lead so that t1> t2. The resin-encapsulated semiconductor device according to claim 1, wherein 3. The plate thickness t1 of the first lead is t1 = 0.
The resin-sealed mold according to claim 1, wherein the second lead has a plate thickness t2 in the range of 10 to 0.16 mm and in the range of t2 = 0.10 to 0.12. Semiconductor device. 4. The first portion exposed on the lower surface of the resin sealing portion.
The length L2 of a part of the outer end of the lead is L2 = 0.35-
The resin-encapsulated semiconductor device according to claim 1, wherein the resin-encapsulated semiconductor device is in a range of 0.45 mm. 5. The center position of the semiconductor pellet fixed to the inner end of the first lead is more eccentrically located on the second lead side than the center position of the resin sealing portion in the longitudinal direction. The resin-encapsulated semiconductor device according to claim 1. 6. When the height from the bottom surface to the top surface of the resin sealing portion is H, the height h1 from the second crank upper surface to the top surface of the second lead is h1 ≧ 0.5H. The resin-encapsulated semiconductor device according to claim 1, wherein: