JP3040235B2 - Lead frame and resin-sealed semiconductor device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a resin-sealed semiconductor device using the same, and more particularly to a package (resin molded portion) structure.

[0002]

2. Description of the Related Art A resin molded portion of a resin-sealed semiconductor device is intended to protect a semiconductor element from an external environment and to prevent destruction by an external force. The improvement in the performance required of the resin mold portion of the recent resin-encapsulated semiconductor device must follow the enhancement of the function of the semiconductor element mounted therein. The enhancement of the function of a semiconductor element is to make the semiconductor element multifunctional. That is, the function of the circuit in the semiconductor element becomes sophisticated, and the circuit becomes complicated. Further, in forming a semiconductor element, the pattern on the surface of the semiconductor element has been miniaturized, and the wiring has been multilayered. As described above, the area of the semiconductor element is becoming larger.

On the other hand, the resin mold portion of the resin-encapsulated semiconductor device must respond to the increase in the area of the semiconductor element, and furthermore, must meet the needs of the market for the development of a small and thin resin mold portion. Resin-sealed semiconductor devices on which semiconductor elements are mounted are roughly classified into pin insertion type and surface mount type. The surface mount type semiconductor device has a thinner resin mold portion than the pin insertion type. Therefore, when the surface-mounted semiconductor device is left in a high-temperature, high-humidity environment, moisture is absorbed into the sealing resin by diffusion from the outside.
In addition, the inside of the surface mount semiconductor device equilibrates with the surrounding environment in a short time. Such a surface-mounted semiconductor device that easily absorbs moisture is mounted on a printed circuit board or the like by soldering.

In this case, the semiconductor device is immersed in a solder bath heated to about 260 ° C.
It is heated by infrared rays of about ℃ or exposed to a gas phase of about 215 ℃ . There is a difference in thermal expansion coefficient between the semiconductor element mounting table and the sealing resin. For this reason, peeling occurs at the interface between the semiconductor element mounting table and the sealing resin that is the material of the resin mold portion due to the heat treatment. In this case, the moisture absorbed or the moisture that has invaded through the tie bar accumulates at the peeled portion. Exposure to the above heat treatment temperature in such a state induces destruction (package crack) of the resin mold portion. That is, the moisture absorbed at the heat treatment temperature reaches the saturated water vapor pressure of water (30 to 40 kg / cm2). This saturated water vapor pressure exceeds the mechanical strength of the resin and induces destruction of the resin mold portion.

The destruction resistance of the resin used for the resin mold portion is proportional to the distance from the lower surface of the semiconductor element mounting table to the back surface of the resin mold portion, that is, the square of the thickness of the sealed resin. That is, in order to manufacture a resin-encapsulated semiconductor device having high resistance to resin destruction, the thickness of the resin may be increased. However, the surface mount type semiconductor device required in the market needs to reduce the thickness of the resin. For this reason, the surface mount type semiconductor device has an unfavorable outer shape against heat treatment when soldering to a substrate.

FIGS. 6 to 8 show a conventional surface mount type semiconductor device. In FIG. 6, as an example, an oxide film, an interlayer insulating film, a polycrystalline silicon layer, and a metal film are formed on a silicon single crystal, and then a fine pattern is formed using a normal photolithography technique. In addition, large-capacity memories are manufactured by combining ordinary diffusion or ion implantation techniques. This semiconductor element 1 has a rectangular parallelepiped shape. It is fixed to the upper surface of the square semiconductor element mounting table 3 of the lead frame 2 with an adhesive such as silver paste or solder. Bonding pads are provided corresponding to the respective circuit lead-out terminals of the semiconductor element mounting table 3. The bonding pad and the plurality of leads 4 are connected via a thin metal wire 5. The semiconductor element 1 connected to the lead 4 in this way is molded with a resin for sealing while leaving the tip region of the lead 4. The resin-sealed semiconductor device is configured as described above.

FIG. 7 shows a cross section of the semiconductor device shown in FIG. Here, for example, the outer dimensions of the resin mold portion 6 are
It is 2.7 mm thick, 8.89 mm wide and 17.15 mm long. The outer dimensions of the semiconductor element mounting table 3 are 0.2 mm in thickness.
mm, width 6.00 mm, and length 15.4 mm. The thickness of the lead 4 is 0.2 mm. Semiconductor element mounting table 3
The thickness from the lower surface to the bottom surface of the resin mold part 6 is 1.05
mm. In this example, due to the size of the semiconductor element 1, the plane area of the semiconductor element mounting table 3 is 6 mm ×
15.4 mm. That is, the ratio of the plane area of the semiconductor element mounting table 3 to the plane area of the resin mold portion 6 is about 61
%.

As described above, the resin molded portion 6 of the resin-encapsulated semiconductor device has a semiconductor element having a larger area, and a small and thin resin molded portion 6 has been developed.

The semiconductor element mounting table 3 is formed of a rigid material such as 42 alloy (iron-nickel alloy). For this reason, when the semiconductor element 1 is resin-molded by the resin mold portion 6, contraction stress is generated.

The generation of the contraction stress will be described in detail with reference to FIG. FIG. 8 is an enlarged view of a region where the semiconductor element 3 and the lead 4 mounted on the semiconductor element mounting table 3 are connected by the thin metal wire 5.

This shrinkage stress is generated in the resin mold portion 6 below the semiconductor element mounting table 3 in the direction of converging at the center of the semiconductor element mounting table 3 (the direction of arrow A in the figure). A stress branch line B is generated to extend vertically from the end of the semiconductor element mounting table 3.

Further, the semiconductor element mounting table 3 is usually formed by punching a thin plate. Thus, the cut surface is perpendicular to the bottom surface. Stress concentrates on the stress concentration portion C of the resin mold portion 6 that contacts the right-angled end of the semiconductor element mounting table 3.

In such a thin resin-encapsulated semiconductor device, cracks easily occur due to heat. For example, when quenching and heating from −65 ° C. to 150 ° are repeated several times, cracks occur in the stress concentration portion C of the resin mold portion 6.
The stress is generated when the semiconductor element mounting table 3 and the resin for sealing the resin mold portion 6 have different coefficients of thermal expansion. The crack generated in the stress concentration portion C is indicated by the stress branch line B.
Grow along. As a result, cracks are formed in the resin mold portion 6 in contact with the outside air. Moisture and impurities contained in the outside air enter from the crack. Moisture and impurities reach the semiconductor element 1 through cracks.

In order to solve these problems, a semiconductor element mounting table having dimples and slits has been proposed.

FIG. 9 is a cross-sectional view of the semiconductor device having dimples cut along the center line of the tie bar.

The dimple structure indicates a structure in which a groove 7 or a depression is provided on the back surface of the semiconductor element mounting table 3.

Separation occurs at the interface between the semiconductor element mounting table 3 and the sealing resin which is the material of the resin mold portion 6. Moisture that has absorbed moisture in the peeling area and water that has entered through the tie bar accumulates in the peeling area. The destruction of the resin mold portion 6 caused by performing the heat treatment in such a state has already been described above. The dimple structure is particularly provided to prevent the separation between the semiconductor element mounting table 3 and the sealing resin which is the material of the resin mold portion 6 from occurring. By providing the groove 7 and the depression in the semiconductor element mounting table 3, the contact area with the resin for sealing is increased.

FIG. 10 is a cross-sectional view of a semiconductor device having a slit, taken along a center line of a tie bar.

FIG. 11 is a plan view of a semiconductor element mounting table having a slit. What is the slit structure?
1 shows a structure in which elliptical holes 8 penetrating through the front surface and the back surface are provided.

Similarly to the dimples, the slits are provided to prevent the peeling from occurring at the interface between the semiconductor element mounting table 3 and the sealing resin which is the material of the resin mold portion 6.

[0021]

However, in the above-described conventional structure, a thin surface-mount type semiconductor device using the semiconductor element mounting table 3 having dimples does not have sufficient mechanical strength. In other words, when the moisture accumulated in the peeled portion reaches the saturated water vapor pressure of the water by the heat treatment, the mechanical strength of the resin is exceeded and the resin mold portion 6 is broken.

The area of contact with the resin for sealing is increased by the grooves 7 and the depressions of the semiconductor element mounting table 3 having dimples. However, the adhesive strength between the resin and the semiconductor element mounting table 3 cannot be significantly improved only by the resin being buried in the grooves 7 and the depressions.

A thin surface-mount type semiconductor device using the semiconductor element mounting table 3 having a slit also does not have sufficient mechanical strength. This is because the hole 8 in the semiconductor element mounting table 3 increases the contact area with the resin for sealing. But not can significantly improve the adhesion strength between the only resin and semiconductor element mounting table 3 are embedded resin in voids 8. However, the adhesive strength of the dimple Sri
Of Tsu door larger than it.

The slit is formed as shown in FIG. When the stress is uniformly distributed in the semiconductor element 1, the semiconductor element mounting table 3 having a slit is suitable. However, when the distribution of the stress is non-uniform or the stress changes in a minute region in the semiconductor element 1, it is difficult to control the stress.

Semiconductor device mounting table 3 having slits
No solder or the like for bonding the semiconductor element 1 is applied to the region of the hole 8. The contact area between the semiconductor element 1 and the semiconductor element mounting table 3 is reduced. For this reason, when the moisture accumulated in the peeling portion reaches the saturated water vapor pressure of the water by the heat treatment, the mechanical strength of the resin is exceeded and the resin mold portion 6 is broken.

As described above, in the conventional semiconductor device having dimples and slits, it is difficult to sufficiently prevent the resin mold portion 6 from being broken. If the resin mold portion 6 is broken or a crack is formed in the resin mold portion 6 that comes into contact with the outside air, moisture and impurities contained in the outside air enter from the crack. Moisture and impurities reach the semiconductor element 1 through cracks. As a result, the adjacent leads 4 are short-circuited by moisture, causing an operation failure.

Further, impurities contained in the sealing resin are extracted by the water. Therefore, the wiring is corroded by the extracted impurities. This corrosion causes disconnection of the wiring.

The moisture that has entered through the cracks enters the solder or silver paste that bonds the semiconductor element 1 and the semiconductor element mounting table 3. For this reason, the semiconductor element 1 is peeled off from the semiconductor element mounting table 3, or the semiconductor element 1 is warped by a later heat treatment. When the semiconductor element 1 warps, the characteristics of each element formed therein are deteriorated.

As described above, when cracks occur in the semiconductor device, the reliability of the semiconductor element 1 is greatly deteriorated.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a highly reliable semiconductor device which is a thin surface-mounted semiconductor device, has sufficient mechanical strength, can control stress in a minute area, and has high reliability.

[0031]

In order to solve the above-mentioned problems, a lead frame according to the present invention comprises a tie bar connected to a frame, a semiconductor element mounting table connected to the tie bar, and a semiconductor element mounting table. , And a plurality of slits and recesses are provided in the semiconductor element mounting table.

In order to solve the above problems, a resin-encapsulated semiconductor device according to the present invention is provided with a plurality of slits and recesses formed in a semiconductor element mounting table of a lead frame, and mounted on the semiconductor element mounting table. The semiconductor device includes a semiconductor element, a lead to which the semiconductor element is connected via a thin metal wire, and a resin mold part that at least surrounds the semiconductor element and the semiconductor element mounting table.

[0033]

According to the above arrangement, a resin for sealing is injected around the recess. Therefore, the semiconductor element mounting table is mechanically and firmly connected to the resin mold portion. Thereby, the corrosion of the wiring due to the impurities contained in the sealing resin can be eliminated. Further, it is possible to have mechanical strength sufficient to prevent the destruction of the resin mold portion.

Further, since it is possible to prevent moisture from entering into the solder or silver paste bonding the semiconductor element and the semiconductor element mounting table, the semiconductor element is peeled off from the semiconductor element mounting table or the semiconductor element is subjected to heat treatment in a later step. No warping.

Further, in the case where the concave portion and the slit are combined and their area is small and the stress is evenly distributed in the semiconductor element 1, even if the stress distribution is not uniform, Since the stress can be controlled in a minute region in the semiconductor element, it is possible to sufficiently cope with a case where the resin mold portion is further reduced in thickness.

[0036]

An embodiment of the present invention will be described below with reference to the drawings. In the following drawings, reference numeral 11 denotes a lead frame, 1
2, 12a and 12b are frames, 13 is a semiconductor element, 14 is a semiconductor element mounting table, 15 is a lead, 16 is a tie bar, 1
7 is a dam bar, 18 is a slit, 19 is a recess, and 20 is a thin metal wire.

FIG. 3 is a plan view of a lead frame used in the resin-sealed semiconductor device according to the first embodiment.

The lead frame 11 is made of, for example, an iron nickel material (Fe-Ni 42%, Fe-Ni 48%, Fe-Ni
50%), Kovar, copper alloy, or the like, and is formed by punching a thin plate or using chemical etching.

The sheet remains in the desired shape, while the other parts are completely removed. As described above, the lead frame 11 is made up of the punched space portion and the thin plate portion.

The region integrating the space portion and the thin plate portion is
It is formed continuously on a thin plate. A frame 12 is provided to continuously and stably form the space portion and the thin plate portion with high reliability. The frame 12a region is provided at both ends of the thin plate along the longitudinal direction. Further, the frame 1 is also provided in an area that blocks an adjacent space portion and a thin plate portion in the short direction of the thin plate.
2b area is provided.

A semiconductor element mounting table 14 is formed on the lead frame 11. The semiconductor element 13 is mounted on the semiconductor element mounting table 14. Therefore, the semiconductor element mounting table 1
The shape of 4 is square. Also, the semiconductor element mounting table 1
A tie bar 16 is provided to fix the tie bar 4.
The tie bar 16 connects the longitudinal frame 12 a and the semiconductor element mounting table 14. Thus, the semiconductor element mounting table 14 is supported by the tie bars 16. At this time, the tie bar 16 extends from the longitudinal end of the semiconductor element mounting table 14. By doing so, the semiconductor element mounting table 14 can be provided stably.

A plurality of leads 15 extend toward the semiconductor element mounting table 14. The lead 15 is formed at right angles to the frame 12b. The number of leads 15 is equal to the number of predetermined pins. The lead 15 is supported by a dam bar 17 to keep the lead 15 in a flat shape. The width of the dam bar 17 is thinner than the frame 12b. The dam bar 17 is formed perpendicular to the frame 12a (parallel to the frame 12b). Both ends of the dam bar 17 are attached to the frame 12a. Thus, the lead 15 is made flat.

The leads 15 extend perpendicularly to the frame 12b from the dam bar 17 to the resin mold portion 21 (dotted line area in the figure) formed after the semiconductor element 13 is mounted. The leads 15 located inside the resin mold portion 21 are formed so that wire bonding between the bonding pads of the semiconductor element 13 and the leads 15 can be easily performed. That is, the leads 15 are bent toward the semiconductor element mounting table 14 located at the center of the lead frame 11. In this manner, the fine metal wires 20 can be easily formed on the bonding pads of the semiconductor element 13 and the tips of the leads 15. Here, since the semiconductor element mounting table 14 and the leads 15 must be electrically insulated, a physical space is provided between them.

FIG. 1 is an enlarged plan view of the semiconductor element mounting table 14 of the resin-sealed semiconductor device of the present invention.

The semiconductor element mounting table 14 is supported by the tie bars 16 as described above. A plurality of slits 18 and recesses 19 are provided in a plane portion. Slit 18
Penetrates from the front surface to the back surface of the semiconductor element mounting table 14. For forming the slit 18, for example, punching or chemical etching is used. These forming methods are based on the lead frame 11.
Is the same as the method of forming. Therefore, even if the slits 18 are provided at the same time when the lead frame 11 is formed, the process does not become complicated. Further, it can be formed by a conventional technique.

The slits 18 are spaced apart by the width of the concave portion 19, and a pair of slits 18 of the same type are formed substantially in parallel . It is pushed out to the back side by a pressing means with the slit 18 as a boundary line, and the semiconductor element is sandwiched between a pair of the slits.
The flat bottom is formed by recessing a part of the
A surface groove type recess 19 is formed. As described above, the concave portion 19 is formed integrally with the slits 18 at both ends.

Although the slit 18 is provided in the direction of the tie bar 16 here, the slit 1 is perpendicular to the tie bar 16.
8 may be formed. In this case, the recess 19 is also formed at right angles to the tie bar 16.

The pair of the pair of slits 18 and the recess 1 9 in the figure is in a line symmetry about the center line A-A 'of the semiconductor device mounting table 14. Alternatively, the lead frame is formed so as to be symmetric with respect to a line BB ′ connecting the centers in the longitudinal direction of the lead frame . Thus, the slit 18 and the concave portion 19
The pair is axisymmetric about each line in order to evenly distribute the stress applied to the semiconductor element mounting table 14. That is, how the stress is applied depends on the shape of the semiconductor element 13. In this example, one semiconductor element 13 is installed on the semiconductor element mounting table 14. A substantially uniform stress is applied to one semiconductor element 13.

For example, in a multichip in which two or more semiconductor elements 13 are mounted on one semiconductor element mounting table 14, stress is not uniformly applied. As described above, when the stress is not uniformly applied to the semiconductor element 13, a pair of the slit 18 and the concave portion 19 is provided according to the distribution state of the stress. That is, in this case, the pairs of the slits 18 and the concave portions 19 are not necessarily symmetrically distributed on the semiconductor mounting table 14.

The concave portion 19 of the embodiment shown here has a width of 0.2 to 1.2 mm and a length of 0.4 to 1.5 mm. The width of the slit 18 is 0.1 to 0.8 mm.

The width and length of the concave portion 19 and the width of the slit 18 depend on processing restrictions. If a press technique or an etching technique is developed, those smaller than the respective lower limit values can be used. If the concave portion 19 and the slit 18 can be finely formed, the dispersion of stress can be controlled with high accuracy. That is, a pair of the slit 18 and the concave portion 19 is provided at a position corresponding to the stress induced in the process step in which the resin mold portion 21 is formed. Thereby, the locally generated stress can be evenly dispersed.

The upper limit of the width of the concave portion 19 varies depending on the area of the semiconductor mounting table. If the area of the semiconductor mounting table increases, a semiconductor mounting table larger than the upper limit can be manufactured. However, when used above the upper limit, stress control becomes difficult, and cracks occur due to stress concentration.

As described above, when the concave portion 19 and the slit 18 are combined and their area is small, when the stress is uniformly distributed in the semiconductor element 13, the stress distribution is of course uneven. Even in this case, since the stress can be controlled in a minute area in the semiconductor element 13, it is possible to sufficiently cope with a case where the resin mold portion is further reduced in thickness.

FIG. 2 shows a cross section taken along the line AA ′ of the resin-sealed semiconductor device of the present invention shown in FIG.

The semiconductor element mounting table 14 has one tie bar 1
6 and the other tie bar 16. Here, the semiconductor element base 14 is shown with three concave portions 19 provided along the AA 'section . The gap between the cross-section is a cross-sectional shape along the longitudinal direction of the slit 18 provided at both ends of the recess 19, and the upper surface line C of the bottom portion of the bottom line B and the recess 19 of the semiconductor element mounting table 14 Is present.

When the resin mold portion 21 is formed, the resin flows into the concave portion 19 and the semiconductor element 13 and the semiconductor element mounting table 14 are firmly connected. For this purpose, the size of the cavity 22 only needs to be large enough to allow the resin of the resin mold portion 21 to flow into the concave portion 19 and penetrate therethrough.

As described above, the resin for sealing is injected around the concave portion 19. For this reason, the semiconductor element mounting table 14
Is firmly connected to the resin mold part. This can eliminate the corrosion of the wiring due to impurities contained in the sealing resin. Further, it is possible to have mechanical strength sufficient to prevent the destruction of the resin mold portion.

Further, since it is possible to prevent the semiconductor element mounting table 14 from invading the solder or silver paste that is bonded to the semiconductor element mounting table 14, the semiconductor element 13 is peeled off from the semiconductor element mounting table 14 or the semiconductor element 13 is warped by a subsequent heat treatment. Nothing.

The semiconductor element 13 is die-bonded to the surface of the semiconductor element mounting table 14 using a synthetic resin adhesive. Although a synthetic resin adhesive was used for this die bonding, the same bonding can be performed using tin-lead solder.

At this time, it should be noted that the atmosphere in the reduced state is sufficiently maintained during the die bonding. If the atmosphere in the reduced state is maintained, the solder will be in an alloy state with the film formed by plating. Therefore, there is no adverse effect such as entering the recess 19 and closing the recess 19.

If a cover is formed in the concave portion 19, a deformed dimple structure generally called is obtained. In this case, the adhesive strength between the semiconductor element mounting table 14 and the semiconductor element 13 is lower than in this embodiment.

The bonding pads formed on the semiconductor element 13 are wire-bonded to the leads 15 with thin metal wires 20. Thereafter, the resin mold portion 21 is formed in a region indicated by a dotted line in FIG. That is, the area within the dotted line is molded with a synthetic resin in a mold. Thereafter, sealing is performed to form the resin mold portion 21.

Thereafter, a resin plate formed between the inside of the dam bar 17 and the wall surface of the resin mold portion 21 is punched. Next, the portion of the dam bar 17 between the leads 15 and the outer peripheral tip of the lead 15 are cut to form the lead 15 into a predetermined shape. Through the above steps, a resin-sealed semiconductor device is completed.

FIG. 4 is a plan view of a lead frame for explaining generation of a resin plate. The overall configuration is the same as described in FIG.

That is, the frame 12 is attached to the lead frame 11.
Is provided. In the region of the frame 12a, a region of the frame 12b is provided in the short direction along the longitudinal direction of the thin plate.

A semiconductor element mounting table 14 is formed on the lead frame 11. The semiconductor element 13 is mounted on the semiconductor element mounting table 14. A tie bar 16 is provided to fix the semiconductor element mounting table 14. As described above, the semiconductor element mounting table 14 is supported by the tie bars 16.

A plurality of leads 15 extend toward the semiconductor element mounting table 14. The lead 15 is supported by a dam bar 17 to keep the lead 15 in a flat shape.

The lead 15 extends perpendicularly to the frame 12b from the dam bar 17 to the resin mold portion 21 (dotted area) formed after mounting the semiconductor element 13. Lead 15
Are bent toward the semiconductor element mounting table 14 located at the center of the lead frame 11. The bonding pad of the semiconductor element 13 and the tip of the lead 15 are
Are tied together.

[0069] Thereafter, when Ru resin model <br/> Lumpur dos in the area indicated by the dotted line in FIG. 4, the inner and the resin mold portion 2 of the dam bar 17
The resin adheres to the C region between the one wall surface. The resin thus attached is called a resin plate. Resin sealing is performed by dam bar 17 to prevent resin from flowing out when resin is injected.
Are formed. The injected resin solidifies the resin flowing toward the dam bar 17 to form a resin plate (also referred to as a thick burr). As described above, the resin plate is generated in the region C between the inside of the dam bar 17 and the wall surface of the resin mold portion 21.
This resin plate is removed for plating the surface of the lead 15 protruding from the resin side wall in a later step. Next, lead 15
The portion between the dam bar 17 and the outer peripheral tip of the lead 15 is cut. The outer peripheral tip is the outer end of the D region in the figure. The lead 15 is formed in a predetermined shape as described above.

The resin for sealing fills the inside of the recess 19 from the cavity 22 of the recess 19. At this time, the resin is
The back surface of the upper semiconductor element 13 is also in contact. In this way, the semiconductor element mounting table 14 is firmly connected to the resin mold section 21.

Even if the semiconductor element 13 thus resin-molded is rapidly heated and rapidly cooled, no crack is generated.

Generally, the coefficient of thermal expansion between the semiconductor element mounting table 14 and the resin mold portion 21 is different. For this reason, rapid heating or rapid cooling generates a stress having a difference in thermal expansion coefficient. However, since the semiconductor element mounting table 14 is provided with the slits 18 and the concave portions 19 as in this embodiment, the stress is dispersed and absorbed by the concave portions 19. For this reason, generation of cracks due to stress can be prevented.

When the occurrence of cracks is prevented, moisture and impurities in the air do not enter the internal semiconductor element 13. Therefore, the reliability of the semiconductor device can be greatly improved.

Further, even when the temperature of the resin-encapsulated semiconductor device thus formed was rapidly increased to about 260 ° C. , the resin mold portion 21 and the semiconductor element mounting table 14 did not peel off. Furthermore, it was confirmed that even if rapid heating and rapid cooling were performed in a temperature range of -65 ° C to 150 ° C , cracks did not occur in the resin mold portion 21.

In the above embodiment, the slits 18 are formed in parallel and the recesses 19 are formed in a straight line. However, the shape of the recesses 19 may be square, star, rhombus, triangle, circle, their deformation,
That is, the side portion may be depressed in a slit shape while leaving a part such as a corner.

The linear recess 19 is suitable for a semiconductor element having a rectangular shape. Because, when the semiconductor element 13 is compressed from the outside, the square semiconductor element 13 is deformed with a larger force than the rectangular semiconductor element 13. That is, in the case of a rectangular shape, it is easily deformed by the stress of strain.

If the square semiconductor element 13 receives an external force uniformly, it is desirable that the drag applied to the semiconductor element 13 be equal. For this purpose, if the shape of the concave portion 19 is a point-symmetric shape, stress can be uniformly received. That is, a square in which the shape of the concave portion 19 is point-symmetric,
A star, a diamond, a triangle, a circle, and their deformed shapes receive uniform stress.

Next, FIG. 5 is an enlarged view around the concave portion 19 when the concave portion 19 is half-etched by a method such as chemical etching.

FIG. 5A is an enlarged view showing a state where half etching is not performed, and FIG. 5B is an enlarged view showing a state after half etching is performed.

Looking at the recess 19 from the cross section, a cavity 22 is formed. The size of the cavity 22 differs before and after the half etching. The thickness of the concave portion 19 is reduced by the half etching. Therefore, the area of the cavity 22 becomes substantially large. As a result, the resin used for the resin mold portion 21 flows more easily from the cavity 22 of the concave portion 19, and the semiconductor element 13 and the semiconductor element mounting table 14 are firmly connected. By performing half etching in this way, the cavity 2
2 can be increased, and the resin of the resin mold portion 21 flows into the concave portion 19 and can easily penetrate. As described above, the material strength of the resin can be given a margin by the half etching.

[0081]

According to the semiconductor device of the present invention, the semiconductor element mounting table is firmly connected to the resin mold portion. Thereby, the corrosion of the wiring due to the impurities contained in the sealing resin can be eliminated. Further, it is possible to have mechanical strength sufficient to prevent the destruction of the resin mold portion.

Further, it is possible to prevent intrusion into the solder or silver paste bonding the semiconductor element mounting table.

Further, even if the distribution of stress in the semiconductor element is not uniform, the stress in a minute area in the semiconductor element can be controlled.

[Brief description of the drawings]

FIG. 1 is an enlarged plan view of a semiconductor element mounting table of a resin-sealed semiconductor device of the present invention.

FIG. 2 is a diagram showing a cross-sectional shape along the line AA ′ of the resin-sealed semiconductor device shown in FIG. 1 of the present invention;

FIG. 3 is a plan view of a lead frame used in the resin-encapsulated semiconductor device of the present invention.

FIG. 4 is a plan view of a lead frame for explaining generation of a resin plate.

FIG. 5 is an enlarged view around a concave portion when half-etching is performed on the concave portion.

FIG. 6 is a perspective view of a conventional surface mount semiconductor device.

FIG. 7 is a sectional view of a conventional surface mount type semiconductor device.

FIG. 8 is a partially enlarged view of a conventional surface mount type semiconductor device.

FIG. 9 is a cross-sectional view of a conventional semiconductor device having dimples.

FIG. 10 is a sectional view of a conventional semiconductor device having a slit.

FIG. 11 is a plan view of a conventional semiconductor element mounting table having a slit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Lead frame 12, 12a, 12b Frame 13 Semiconductor element 14 Semiconductor element mounting base 15 Lead 16 Tie bar 17 Dam bar 18 Slit 19 Concave part 20 Metal thin wire

Claims (11)

(57) [Claims] [1 claim: a tie bar connected to the frame, and a lead extending plural toward the connected semiconductor element mounting table to said tie bar to said semiconductor element mounting table, and a dam bars connected to the lead The semiconductor device mounting table includes a plurality of slits and the half-space between a pair of the slits.
A flat bottom formed by recessing a part of the conductive element mounting table
A lead frame provided with a flat three-sided groove-shaped recess. 2. A pair of the slits penetrate from a front surface to a rear surface of the semiconductor element mounting table in a pair ,
2. The semiconductor device according to claim 1 , wherein said pair of slits are formed so as to be pushed out to the back side of said semiconductor element mounting table.
Lead frame according to. 3. The lead frame according to claim 2 , wherein the shape of the recess is point-symmetric. 4. A plurality of slits formed in a semiconductor element mounting table of a lead frame and a pair of said slits.
The bottom of the semiconductor element mounting table
And the recess of the flat three-sided groove-type, a semiconductor element mounted on the semiconductor element mounting on table, the electrode portion of the semiconductor element, a lead connected via a thin metal wire, said semiconductor element 及
Fine the resin-sealed semiconductor device characterized by comprising a resin mold portion Komu viewed wrap the semiconductor element mounting table. 5. A pair of said slits penetrate from a front surface to a rear surface of said semiconductor element mounting table in a pair ,
5. The semiconductor device according to claim 4 , wherein said pair of slits are formed so as to be pushed out to the back side of said semiconductor element mounting table.
Resin-encapsulated semiconductor device according to. Wherein said slit penetrates from the surface of the semiconductor element mounting table in parallel pair to the back, the concave portion, wherein is extruded in the semiconductor element mounting table back side between said pair of slits The resin-sealed semiconductor device according to claim 4 , wherein the semiconductor device is formed. The method according to claim 7, wherein the slit and the recess, according to claim 4 or 5, characterized in that it forms a cavity between the upper surface of the bottom portion of the bottom and front Symbol recess of the semiconductor element mounting table Resin-sealed semiconductor device. 8. A semiconductor device mounting table for a lead frame.
A plurality of slits formed and a pair of the slits
The bottom of the semiconductor element mounting table
A flat three-sided groove-shaped recess is provided on the semiconductor element mounting table.
The semiconductor element placed and the electrodes of the semiconductor element
A lead connected through a metal wire and the semiconductor element and
And the semiconductor element mounting table, and the slit
And the recess, the bottom of the semiconductor element mounting table and the front
Fill the cavity formed between the bottom of the recess and the top of the recess.
Tree Aburafutome type semiconductor device you comprising the resin molded portions. 9. A semiconductor device mounting table for a lead frame.
Made is, the passes through the center of the semiconductor element mounting table, and a plurality of slits arranged in line symmetry with respect to any edge parallel to the side line of the semiconductor element mounting table, a pair of the slit
The semiconductor element mounting table is formed by depressing a part of the mounting table.
A three-sided groove-shaped recess having a flat bottom portion;
A semiconductor element installed on a table, and a power supply for the semiconductor element.
A lead connected to the pole via a thin metal wire,
Enclose the conductor element and the semiconductor element mounting table, and
The semiconductor element mounting table is formed by the slit and the recess.
Formed between the bottom of the recess and the upper surface of the bottom of the recess.
And a resin mold part filled with a cavity .
That tree Aburafutome type semiconductor device. 10. The recess has a width of 0.2 to 1.2 mm,
6. The resin-sealed semiconductor device according to claim 5 , wherein the length is 0.4 to 1.5 mm. 11. The resin-sealed semiconductor device according to claim 5 , wherein the shape of the recess is point-symmetric.