JPH0254957A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To increase bonding strength between leads and a package by placing a semiconductor pellet having wire bonding parts at its both sides on an insulating sheet and disposing a plurality of leads at the below side of the above sheet and then, making slender through holes at inner lead parts communicating with the lead when the leads are bent. CONSTITUTION:A semiconductor pellet 14 on which wire bonding parts 9A and 9B are mounted at both end parts is placed on an insulating sheet 11 and pointed ends of a plurality of leads 6 and 7 which pass through below the sheet 14 are located on the bonding parts 9A and 9B and they are connected each other by using bonding wires 15. In this configuration, the leads 6 and 7 are bent at right angles at end parts of a resin package 16 which supports the leads and further, a slender, long through holes 10 are made at inner leads 8 of the leads communicating with respective bent parts. In this way, when the leads 6 and 7 are buried into the package 16, the through holes 10 which are made in the inner leads 8 having broad widths make bonding strength strong and no cracks develop in the package 16.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to semiconductor device manufacturing technology, particularly to improvement of lead wiring technology. The present invention relates to a technique effective for use in manufacturing a semiconductor integrated circuit device (hereinafter sometimes referred to as DILP/IC1 or simply IC).

[Conventional technology]

Traditionally, memory-based semiconductor integrated circuit devices have a capacity of 300m1! A dual-in-line resin-sealed package with a bending width of (7.62 m) is used.

Recently, as the degree of integration of memory-based semiconductor integrated circuit devices has increased, semiconductor pellets have become larger in the longitudinal direction. Furthermore, memory-based semiconductor integrated circuit devices are characterized in that the bonding pads on the semiconductor pellet are arranged biased toward both short sides of the semiconductor pellet, which is formed into an elongated shape.

Therefore, if the degree of integration of memory semiconductor integrated circuit devices increases further, it will become difficult to maintain a bending width of 300ml in a dual-in-line resin-sealed package. There is. In other words, dual
In-line type (7) When trying to accommodate a semiconductor pellet that is long and has bonding pads biased toward the short side in a 1m long I1 package, wiring for the inner leads within the package is required. This is because there is a lack of space.

Therefore, even when sealing semiconductor pellets that are long and have bonding pads biased toward the short sides, a resin-sealed package can secure sufficient wiring space for the inner leads. It is desired to provide a semiconductor device having the following features.

In order to meet such demands, the following semiconductor devices have been proposed.

That is, a semiconductor pellet, a plurality of leads that are electrically independent from each other and constitute external terminals, bonding wires that are bridged between each lead and the semiconductor pellet, and these semiconductor pellets. A semiconductor device comprising a package for resin-sealing leads and a group of bonding wires, the inner portions (hereinafter sometimes referred to as inner leads) of at least some of the leads of the group of leads are sealed in the package. Wiring is provided below the semiconductor pellet, and an insulating layer is interposed between the inner lead and the semiconductor pellet.

According to this semiconductor device, at least some of the inner leads of the lead group are partially wired below the semiconductor pellet within the resin-sealed package.
Sufficient wiring space can be secured for this inner lead.

Thus, for example, dual
In an in-line resin-sealed package, even if you are trying to accommodate a semiconductor pellet that is long and has bonding pads biased toward its short side, it is difficult to keep the inner leads inside the package. Can be wired sufficiently.

Further, since an insulating layer is interposed between the semiconductor pellet and the inner lead wired below the semiconductor pellet, good insulation between the semiconductor pellet and the lead group can be maintained. The semiconductor pellet can be firmly fixed within the resin-sealed package.

An example of such a semiconductor device is as follows.
Japan Patent Office Published Patent Publication, JP 57-114261
No., JP-A No. 61-218139, and JP-A No. 61-Sho.
There is No.-258458.

[Problem to be solved by the invention]

In the semiconductor device described above, when a temperature cycle is applied or applied, the semiconductor pellet, the lead, the resin-sealed package, and the insulating layer interposed between the semiconductor pellet and the lead are damaged. Cracks that are considered to be caused by differences in thermal expansion coefficients of materials are
The inventor of the present invention has revealed that there is a problem in that resin-sealed packages have localized problems.

An object of the present invention is to provide a semiconductor device and a method for manufacturing the same that can prevent the occurrence of racks as described above.

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

[Means to solve the problem]

A summary of typical inventions disclosed in this field is as follows.

That is, a semiconductor pellet, a plurality of leads that are electrically independent from each other and each constitute an external terminal,
The device includes bonding wires bridged between the inner portion of each lead and the semiconductor pellet, and a package for sealing the semiconductor pellet, the inner portion of the lead, and the bonding wire with resin, and A part of the inner part of at least some of the leads is wired below the semiconductor pellet within the package, and there is no space between this inner part group and the semiconductor pellet! In the semiconductor device in which the & layer is interposed, at least some of the leads of the group of leads wired below the semiconductor pellet have a resin portion on the boundary line facing the outer edge of the semiconductor pellet. In order to increase the occupied area ratio, a through hole is opened across this boundary line in both the interior and exterior directions.

Further, in the semiconductor device, at least some of the leads of the group of leads wired below the semiconductor pellet are arranged such that stress between the leads is reduced at least in a portion corresponding to the periphery of the lower surface of the semiconductor pellet. Each lead is branched into multiple branches in the width direction.

Further, in the semiconductor device, the insulating layer is formed of an insulating sheet formed in a rectangular sheet shape, and the short side of the insulating sheet is smaller than the short side of the semiconductor pellet (by setting). This is what I did.

[Effect]

According to the first means described above, the effective area of the inner lead is reduced by the through hole formed in the inner lead wired below the semiconductor pellet, and
Since the effective area of the resin part is increased, the adhesive strength between the lead and the resin part is increased. As a result, the occurrence of resin crank inside the package due to stress generated under conditions of temperature cycling is prevented.

In addition, according to the second means in which the inner lead is branched into a plurality of pieces in the width direction, even if the upper surface of the lead group is separated from the resin part, the inner leads are separated from each other by crack-like gaps. Since the width can be narrowed, stress at the end of the lead can be reduced without reducing the strength of the lead and the strength of fixing the lead. As a result, the occurrence of resin cracks due to stress that occurs under conditions where temperature cycles are applied can be prevented.

According to the third means in which the short side dimension of the vA edge receipt interposed between the semiconductor pellet and the lead group is smaller than the short side dimension of the semiconductor pellet, the resin portion generated at the end of the insulating sheet can be reduced. Since the stress concentration at the end of the insulating sheet can be reduced to a minimum, it is possible to prevent resin cracks from occurring at the end of the insulating sheet due to the stress generated under conditions where the temperature cycle is severe.

[Example 1] Fig. 1 is a partially cutaway perspective view showing a DILP-IC which is an embodiment of the present invention, Fig. 2 is a side view of the DILP-IC, and Fig. 3 is a front view of the DILP-IC. It is a diagram.

In this embodiment, the semiconductor device according to the present invention is a DILP.
・It is configured as an IC17 (semiconductor bellet) 14
and an outer part (hereinafter referred to as outer lead) 7, which is electrically independent from each other and constitutes an external terminal, and which is drawn out to the outside of the resin-sealed package (described later), and which is wired inside the package. A plurality of glue parts 6 consisting of an inner part (hereinafter referred to as inner lead) 8,
It includes bonding wires 15 that are bridged between each inner lead and the semiconductor pellet, and a package 16 that seals the semiconductor pellet, the inner lead, and the bonding wire group with resin. At least some of the inner leads 8B of the group of 8 inner leads are partially wired below the semiconductor pellet within the package, and the inner leads 8B of the group of inner leads 8B are wired below the semiconductor pellet. An insulating sheet 11 is fixed on a portion of the insulating sheet, and a semiconductor pellet is bonded onto this insulating sheet. Furthermore, a through hole 10 is formed in each inner lead 8B so as to extend inside and outside the outer edge of the semiconductor pellet 14.

Further, on the outside of the package, the outer lead group is bent into a bat wing shape, and the bending width of the opposing leads is set to 300 ml. The DILPiC configured as described above is manufactured by the following manufacturing method.

Hereinafter, a method for manufacturing DILP-Ic, which is an embodiment of the present invention, will be explained. With this explanation, the DILP・
Configuration details for the IC are revealed.

In this embodiment, the method for manufacturing a DILP-IC according to the present invention includes a multi-lead frame 1 shown in FIG.
is used. This multiple series-1 frame is 4270
A thin (for example, wall thickness of 0.25
+w) Using a plate material, it is integrally formed by suitable means such as punching press processing or etching processing. In this multiple lead frame 1, a plurality of unit lead frames 2 are arranged in parallel in one row in one direction.

The unit lead frame 2 includes a pair of outer frames 3 each having a positioning hole 3a, and both outer frames 3.3 are parallel to each other at a predetermined interval and extend in series. A pair of section frames 4 are disposed parallel to each other between both outer frames 3.3 and integrally constructed between adjacent unit lead frames 2.2. A unit lead frame 2 is constructed within a rectangular frame.

In each unit lead frame 2, a pair of dam members 5 are disposed on both outer frames 3.3 at inner positions of both section frames 4.4 so as to be parallel to each other and have a substantially symmetrical shape. 6-car dam member being constructed 5.5
A plurality of glue portions 6 are arranged at equal intervals in the longitudinal direction,
They are parallel to each other and integrally protrude perpendicular to the dam member 5. Adjacent leads 6 in the dam member 5.
The portion between 6 substantially constitutes a dam 5a that blocks the flow of resin, which will be described later, during package molding, which will be described later.

As will be described later, the outer portion of each lead 6 protrudes to the outside of the resin-sealed package, and therefore constitutes an outer lead 7. The tip of each outer lead 7 is mechanically attached to the section frame 4. By being connected to each other, the state is maintained.

On the other hand, since the inner portions of each lead 6 are sealed inside a resin-sealed package as described later, they constitute inner leads 8, respectively. The inner ends, which are the free ends of each inner lead 8, are arranged so as to be aligned on a straight line passing through predetermined positions on both short sides in the empty space of the unit lead frame 2. The portions substantially constitute wire bonding portions 9 by being opposed to bonding pads of a semiconductor pellet to be described later.

In this embodiment, the eight groups of inner leads can be roughly divided into two types. That is, one is a normal DILP
Similar to the inner leads in an IC, the inner leads (hereinafter referred to as peripheral inner leads 8A) are wired using the empty space at the periphery of the unit REIT' frame 2.
That's what it means. ), and the other is the normal DILP-I
Completely different from the inner lead in C, the inner lead (hereinafter referred to as center inner lead 8) is wired using the empty space in the center of the unit lead frame 2.
It's called B. ). The wire bonding portion 9A of the peripheral inner lead 8A extends from the peripheral side toward the center, and the wire bonding portion 9B of the center inner lead 8B extends from the center toward the peripheral portion. has been done. However, the wire bonding portions 9A and 9B in the inner leads 8A and 8B in both the peripheral portion and the central portion are also aligned in a straight line at a predetermined position.

The central inner lead 8B group will be wired below the semiconductor pellet to be described later.

In this way, the unit lead frame 2 according to this embodiment
In this case, the group of central inner leads 8B are wired in the central region within the empty space of the unit lead frame 2, so the entire empty space can be used extremely effectively. Even if the empty space is set to be elongated, all eight groups of inner leads can be properly and safely wired without coming into contact with each other.

Furthermore, in this embodiment, each center inner lead 8
A through hole 10 is formed in each of the holes B. This through hole 10 is a hole for increasing the occupied area ratio of the resin part at the boundary line opposite to the outer edge of the semiconductor pellet, which will be described later, of this inner lead 8B, and the details of the operation of this through hole will be explained later. . This through hole 10 is formed in an oval shape and extends inwardly and outwardly, straddling the boundary line. That is, the through hole 10 extends from a position directly below the semiconductor pellet to the dam member 5.

The lead frame 1 constructed in this way is subjected to insulating sheet bonding work and bonding work for each unit lead frame 2.
A pellet bonding operation is performed followed by a wire bonding operation.

These bonding operations are sequentially performed for each unit lead frame 2 by pitch-feeding the lead frame 1 in the serial direction. Through these bonding operations, intermediate products shown in FIGS. 5 and 6 are manufactured.

First, by an insulating sheet bonding operation, the insulating sheet 11 is placed on the central inner lead 8B group of the unit lead frame 2 by bonding Ji51 made of adhesive.
2 is interposed and bonded. At this time, the insulation sheet
are arranged so that their outer edges are perpendicular to the substantially central portions in the longitudinal direction of the through holes 10 respectively opened in the group of central inner leads 8B.

In this embodiment, the insulating sheet 11 is made of a material with good insulation properties, such as a polyimide resin film. The insulating sheet 11 is formed into a rectangular shape that is slightly larger than the planar shape of a semiconductor pellet to be described later. In view of the correlation between maintaining insulation and mechanical strength, it is desirable that the thickness of the insulating sheet 1 is about 125 μm.

As the adhesive forming the bonding layer 12, a thermoplastic adhesive such as polyether amide imide is used.

Next, a semiconductor pellet (hereinafter referred to as a pellet) into which the required integrated circuit has been fabricated in the previous process.

) 14 is an insulating sheet l in each unit lead frame 2
A bonding layer 13 made of adhesive is interposed on top of the bonding layer 13 for bonding. At this time, the pellets 14 are arranged approximately concentrically with respect to the insulating sheet 11.

As the adhesive for forming the bonding layer 13 that fixes the pellets to the insulating sheet, for example, a non-conductive paste material on a thermosetting polyimide resin adhesive such as polypyromellitic acid imide or polyketone imide, for example,
Multilayer adhesives are used that are made by laminating silicone rubber, epoxy rubber, epoxy resin, polyimide resin, etc.

In this embodiment, the pellet 14 is a 4 megabit random access memory (hereinafter referred to as 4MDRA).
There is a thing called M. ) type semiconductor integrated circuit element, and the circuit layout is as shown in FIG.

That is, the memory mat 2 is placed in the center of the pellet 14.
0 is provided, and in the center in the X direction, Y is provided parallel to the Y axis.
A decoder 21 is provided along the memory mat 20,
In the center of the Y direction is a word driver 2 parallel to the X axis.
2 and an X decoder 23 are provided along the memory mat 20. Further, at one end in the longitudinal direction, a RAS system circuit 24, a CAS system/WE system circuit 25, and an X9, IO, and Y9.10 address buffer 26 are provided, and a main amplifier 27 is provided inside thereof, and a corner A Dout buffer 28 is provided in the section. At the other end, there is a RAS circuit 24, an X address buffer 29, an X generator 30, an X, an X generator 31. A Y address buffer 32 and a 5HR-PC generator 33 are provided. In addition, a sense amplifier, common input/output, and common source 34 are provided at the right end in the short direction.
The upper terminal 20 of the memory mat 20 is located at the upper end of the left side.
A is provided, and a lower terminal 20B of the memory mat 20 is provided at the lower end.

Then, as shown in Fig. 8, this pellet 1
Electrodes (pads) Al to A of each circuit provided in 4
+s, P, and S-P are arranged at both ends of the pellet in the longitudinal direction, that is, at both short sides. 1t
i (Pads) At to A+s are bonding pads, and electrodes (pads) P1 to P are blowing pads used during electrical property testing.

Next, in the wire bonding process, the insulating sheet 1
T-dig bud A1 with 14 pellets bonded to 1
A wire 15 is connected between A11 and the wire bonding portion 9 of the inner lead 8 in each unit lead frame 2.
are bridged by bonding their respective ends.

Examples of the material for this bonding wire 15 include:
A gold (Au) wire with a diameter of 30 μm is used.

Further, as the wire bonding device, an ultrasonic thermocompression type wire bonding device (not shown) is used.

This wire bonding device uses a capillary as a bonding tool, and the first bonding part on the pellet side is formed by pressing a ball melted at the tip of the wire material by the discharge electrode against the electrode pad of the pellet by the capillary. is formed by.

Further, the second bonding portion on the inner lead side is formed by pressing the intermediate portion of the wire material against the bonding portion of the inner lead while being energized with ultrasonic energy by a capillary. In addition, inner lead 8
A silver plating III (not shown) is deposited on the surface of the bonding portion 9 in the region of the bonding portion 9 .

As a result, the integrated circuit built into the pellet 14 is electrically extracted to the outside via the electrode pads, wires 15, inner leads 8, and outer leads 7.

The multiple lead frames that have been pellet- and wire-bonded in this way are then molded using a transfer molding apparatus as shown in FIGS. used to simultaneously mold unit lead frames.

The transfer molding apparatus 50 shown in FIGS. 9 and 10 is equipped with a pair of upper mold 51 and lower mold 52 that are clamped together by a cylinder device or the like (not shown). A plurality of upper mold cavity recesses 53a and lower mold cavity recesses 53b are recessed in the mating surface of the mold 51 and the lower mold 52 so as to cooperate with each other to form the cavity 53. The tee 53 is configured to accommodate the insulating sheet 11.

A bot 54 is provided on the mating surface of the upper mold 51,
A plunger 55, which is moved forward and backward by a cylinder device (not shown), is attached to the bot 54 using a resin as a molding material (epoxy resin with reinforcing material such as silica, hereinafter referred to as
It's called resin. ) is inserted so that it can be delivered.

On the other hand, on the mating surface of the lower die 52, a cull 56 is arranged and sunk in a position facing the bot 54, and a plurality of runners 57 are arranged radially and sunk so as to connect to the bot 54, respectively. It is set up. The other end of each runner 57 is connected to the lower cavity recess 53b, and a gate 58 is formed at the connection portion so that resin can be injected into the cavity 53. In addition, an escape recess 59 on the mating surface of the lower die 52 is a rectangle slightly larger than the outer shape of the multiple lead frame 1 so that the thickness of the lead frame can escape. It is embedded in.

When molding a resin-sealed package using the transfer molding apparatus using the multi-lead frame 1 having the above configuration, each cavity 53 in the upper mold 51 and the lower mold 52 is formed by a pair of molds in each unit lead frame 2. Each corresponds to the space between the dam members 5.5.

During transfer molding, the multi-lead frame 1 according to the above-mentioned structure has a relief recess 5 recessed in the lower mold 52.
9, insulating sheet 1 in each unit lead frame 2
1 and pellets 14 are arranged and set so as to be accommodated in each cavity 53, respectively. At this time,
As shown in FIG. 10, the central inner lead 8
The configurations of the mold and lead frame are set such that each of the through holes 10 opened in group B projects inwardly and outwardly from the opening edge of the four cavity parts 53b.

Subsequently, the upper mold 51 and the lower mold 52 are clamped, and the bond 5
4, resin 60 is fed into each cavity 53 by a plunger 55 through a runner 57 and a gate 58, and is press-fitted therein. The resin 60 injected into the cavity 53 from the gate 58 is diffused throughout the cavity 53.

At this time, since the through-holes 10 are formed in each of the central inner leads 8B, the resin 60 can easily flow through these through-holes 10, so that the resin 60 enters the upper and lower spaces of the cavity 53. It spreads effectively and reliably fills the entire cavity 53.

Further, the inside of this through hole 10 is also filled with the resin 60. A portion of the resin 60 filled inside the through hole 10 reaches the portion of the through hole 10 extending from the inside of the cavity 53 to the outside.

After injection, the resin is thermally cured to form a resin-sealed package 1.
6 is molded, the upper mold 51 and the lower mold 52 are opened, and the group of packages 16 is released from the mold by an ejector pin (not shown).

In this way, as shown in FIG. 11, the multiple lead frame 1 on which the packages 16 have been molded is removed from the transfer molding apparatus 50. The insulating sheet 11, pellets 14, inner leads 8, and bonding wires 15 are sealed with resin inside the package 14 molded with resin in this manner.

Thereafter, in the resin-sealed package 16, the burrs generated between the dam 5a and the outer leads 7.7 on both sides, and the burrs generated in the exposed space of the through hole IO are removed.

Next, a solder coating is applied to the entire exposed metal surface of the multiple lead frame by a suitable means such as an electroplating device (not shown) or a solder dipping device (not shown).

In addition, in the lead cutting and forming process, the multi-lead frame is processed by a lead cutting device (
After the outer frame and dam are cut off by a reed molding device (not shown), the outer lead is bent into a bat wing shape by a reed molding device (not shown). At this time, since the through hole 10 is formed in the bent portion 7a of the outer lead 7, the bending can be properly performed without generating excessive strain force.

By the manufacturing method described above, DILP-1c17 shown in FIGS. 1 to 3 was manufactured.

Next, the action will be explained.

The DILP-IC manufactured by the above manufacturing method is subjected to a sampling inspection before being shipped. As a sampling inspection,
Environmental tests will be conducted including temperature cycling tests and thermal shock tests. Further, when this DILP-IC is mounted on a printed wiring board or the like, the DILP-IC is heated also by solder dipping treatment or reflow soldering treatment, and is therefore subjected to temperature cycles. Furthermore, even when the DILP-IC is in operation after being mounted, it is heated due to self-heating or the influence of other electronic devices, so it may be placed under a temperature cycle.

By the way, when a temperature cycle is applied to the DILP-IC during such an environmental test or during mounting, the inner lead group is wired below the pellet, and an insulating layer is placed between the central inner lead group and the bellet 1-. The present inventor has revealed that in a semiconductor device equipped with an interposed resin-sealed package, there is a problem in that a rack occurs due to the resin-sealed package.

In other words, during temperature cycling, the thermal expansion coefficient (42N
i-Fe tx=o, 4X10-'/”C, Cu cr
= 1. 7
．． OX 10-S/''C), cracks are locally generated within the body of the resin-sealed package at the contact points with the inner leads.

However, in this embodiment, the central inner lead 8B
Since the through hole 10 is opened so as to extend from the position directly below the pellet 14 to the outside of the package 16, the occurrence of cracks due to stress that occurs when temperature cycles are applied is prevented. .

That is, the center inner lead 8B in which the through hole 10 is formed has a smaller area ratio to the sealing resin portion than the conventional center inner lead in which no through hole is formed. The adhesive strength between the lead 8B and the sealing resin portion is increased. As a result, the stress generated when temperature cycles are applied to the central inner lead 8
Even if this occurs between the center inner lead 8B and the resin part bonded to it, the bond between the central inner lead 8B and the resin part can withstand this, so cracks will not occur in the sealing resin part. do not have.

Here, FIG. 12 is a diagram showing the results of an experiment regarding the relationship between the resin thermal expansion coefficient α and the number of cycles when 1% of all cracks occur under temperature cycling conditions.

In FIG. 12, (Al) is a characteristic curve showing the case of this embodiment in which a rectangular through hole is formed in the central inner lead, and (B) is a characteristic curve in which a through hole is formed in the central inner lead. 3 is a characteristic curve showing the case of a conventional example in which there is no

Figure 13 shows the resin occupation area ratio at the edge of the package,
It is a diagram showing the results of an experiment regarding the relationship with the number of temperature cycles.

In FIG. 13, (A) has a resin thermal expansion coefficient α of 1.
This is the characteristic line in the case of Ox 10-'/'c, (B)
is a characteristic curve when the resin thermal expansion coefficient α is 1.7×10 −′/°C.

FIG. 14 is a diagram showing the results of an experiment regarding the relationship between the hardness of the lead frame and the number of times the lead breaks due to 90-degree repeated bending in this example.

In FIG. 14, (A) is a characteristic curve showing the case of this embodiment in which a rectangular through hole 10 is formed in the inner lead, and is 0.5.0.45.0°4.0.25 etc. The number is the lead width of the portion where the rectangular through hole is formed. (B) is a characteristic curve showing a conventional example in which no through hole is provided in the inner lead.

It will be understood from the experimental results shown in each of these diagrams that the above-mentioned effects can be obtained according to this embodiment.

According to the embodiment described above, the following effects can be obtained.

(1) By wiring at least some of the inner leads of the inner lead group below the semiconductor pellet within the resin-sealed package, sufficient wiring space can be secured for the inner lead group.
As in the case of highly integrated memory-based semiconductor integrated circuit devices, dual-in-line resin-sealed packages are elongated and the bonding pads are placed biased toward the short sides. Even if a semiconductor pellet is to be accommodated, the inner leads can be properly wired within the resin-sealed package.

(2) Due to the above (+), it is possible to maintain the standard of 300 m1 I for the bending interval even in DILP ICs mounted with highly integrated pellets such as 4M DRAM, so it is possible to maintain the standard of 300 m1 I for the bending interval, so it is suitable for memory semiconductor integrated circuits. The desired versatility or compatibility can be maintained in the device.

(3) By wiring at least some of the inner leads of the inner lead group below the semiconductor pellet within the resin-sealed package, the free space outside the semiconductor pellet can be set relatively large. , the degree of freedom in designing the inner lead wiring can be relatively increased, and changes in the arrangement of the bonding pads in the semiconductor pellet can be easily handled.

(4) Prepare a lead frame in which at least some of the inner lead groups are wired in the empty space in the center, and fix an insulating sheet on the inner lead group in the center of the lead frame, By bonding the semiconductor pellet onto this insulating sheet, the semiconductor pellet can be firmly fixed in the resin-sealed package, and the insulation between the semiconductor pellet and the inner lead can be maintained well. Also in (1), it is possible to prevent the performance of a semiconductor device equipped with a resin-sealed package from deteriorating.

(5) By creating a through hole in the central inner lead to increase the area ratio of the sealing resin part, the adhesive strength between the inner lead and the sealing resin part can be increased, so temperature cycles can be reduced. It is possible to prevent cracks in the sealing resin from occurring due to stress generated under such conditions.

(6) By extending the through hole to the outside of the package, the bending load during bending of the outer lead can be alleviated, so a gap will not be generated between the lead and the edge of the package opening during bending. It is possible to prevent this from occurring.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, as shown in FIGS. 15 to 22, the through hole formed in the central inner lead can be modified as appropriate.

The through hole 10A shown in FIG. 15 is formed to have a large width inside the resin-sealed package 1G, and is formed to have a small width outside the package 16.

According to this through hole 10A, it is possible to ensure a sufficient area ratio of the sealing resin portion inside the package, and to suppress the occurrence of fraying to a minimum level outside the package. can. Moreover, since the reduction in the cross-sectional area of the outer lead 7 is suppressed,
A decrease in the strength of the outer lead can be avoided.

Further, in this embodiment, the narrow external portion of the through hole 10A does not extend to the bent portion of the outer lead 7.
Therefore, even if burrs are generated in this area, the bending process of the outer lead 7 will not be affected.Furthermore, since the degree of burr generation is extremely slight, it is possible to omit the burring process. It is.

The through hole 10B shown in FIG.
The externally exposed portion of the outer lead 7 is formed to have a small width, and this narrow portion extends to the bent portion of the outer lead 7.

According to this embodiment, by setting the dimensions of the narrow portion, it is possible to achieve a balance between the effect of reducing the bending load during bending of the outer lead 7 and the strength of the outer lead after bending.

Through hole 1 shown in FIG. The outer end of the OC is formed into a semicircular shape, and only the semicircular portion is exposed to the outside of the package 16.

According to this embodiment, the occupied area ratio of the sealing resin inside the package/jet 16 can be increased to a sufficient degree.

The through hole LOD shown in FIG. 18 is formed in a rectangular shape with slightly chamfered outer ends at both corners, so that the rectangular portion is exposed from the package 16 by a minute dimension. is set to .

According to this embodiment, the degree of burr generation can be suppressed compared to the case shown in FIG. 17.

The through hole 10E shown in FIG. 19 is configured such that its outer end is located on the inner and outer boundaries of the package 16.

According to this embodiment, it is possible to sufficiently increase the occupied area ratio of the sealing resin inside the package 16, and it is also possible to avoid exposing the through hole 10E to the outside. Therefore, generation of burrs can be avoided, and a decrease in the strength of the outer lead 7 can also be avoided.

The through hole 10F shown in FIG. 20 is configured such that its outer end is located near the boundary line inside the package 16.

According to this embodiment, even if an error occurs in the alignment accuracy of the molds during molding of the package 16 as described above, the end of the through hole 10F may be exposed to the outside of the package 16. can be avoided.

In the modification shown in FIGS. 21 and 22, a rib IOG formed of resin on the outer lead 7 is formed integrally with the through hole 10 exposed to the outside of the package 16. The through holes 10 of this rib IOG are filled with resin, and the outer lead 7 in which the through hole IO, which is formed to protrude into the inner space of the bent portion of the outer lead 7, is reinforced by this rib IOG. That will happen.

[Embodiment 2] FIG. 23 is a partially cutaway perspective view showing another embodiment of the present invention.

In this embodiment, each of the group of central inner leads 8B wired directly below the pellet 14 is divided into two parts in the width direction of the lead at the portion facing the periphery of the lower surface of the semiconductor pellet 14, and each of the divided parts 1 Gap between day and 18 1
A resin portion is formed in 8a.

According to this embodiment, the portion of the central inner lead 8B that is subjected to high thermal stress due to the pellet 14 is divided into a plurality of narrow portions and separated from each other with an interval, so that the leads are sealed. The stress acting on the resin sealing portion is reduced, and as a result, occurrence of crank inside the resin sealing package 16 can be prevented. Its action is explained as follows.

By the way, when a pellet is mounted on the central inner lead group through an insulating sheet, the upper surface of the lead in the part where the semiconductor pellet is not mounted is caused by the difference in linear expansion coefficient between the semiconductor pellet and the sealing resin. thermal stress is applied.

Since the coefficient of linear expansion of resin is usually larger than that of semiconductor pellets, tensile stress as shown by F in Fig. 24 is generated in the lead portion around the semiconductor pellet by cooling from the resin mold temperature. The stress is particularly large near the lower end of the semiconductor pellet.

The adhesive interface between the lead and the encapsulating resin has only a very weak adhesive strength against tensile stress, so the encapsulating resin easily peels off on the top surface of the lead around the semiconductor pellet, and this area It becomes impossible to bear tensile stress.

Therefore, the tensile stress between adjacent leads is F! in FIG. Concentrate on the top end of the lead as shown in
Under severe temperature environments such as temperature cycle tests, there was a problem in that resin cranks C occurred between the leads, as shown in FIG. 26. Here, FIGS. 25 and 26 are sectional views taken along the line XX in FIG. 24.

Then, in the vicinity of the lower end of the semiconductor pellet, the upper surface of each lead is peeled off, resulting in a state in which crack-like gaps are periodically lined up in the tensile stress field. When cracks are arranged periodically in a tensile stress field, the stress at the crack ends becomes smaller as the crack length becomes shorter and as the ratio between the crack length and the crack interval becomes smaller. In this periodic crack model, the crack length corresponds to the width of each lead sealed in the resin-sealed package, and the crack spacing corresponds to the lead spacing.

Therefore, by narrowing the width of the central lead immediately below the lower end of the semiconductor pellet, it is possible to reduce the stress at the inner lead end of the resin filled between adjacent inner leads. However, if the width of the central inner lead is narrowed while maintaining the conventional structure, the strength of the lead and the strength of fixing the lead with the resin will be insufficient, so the lead width cannot be sufficiently narrowed.

Therefore, according to this embodiment in which the central inner lead is divided into a plurality of leads in the width direction, even if peeling occurs on the upper surface of the lead, the width of each crack-like gap can be narrowed, which improves the strength of the lead. without reducing the fixation strength of
Stress at the lead ends can be reduced.

The manufacturing method of DILP・■C17A shown in FIG. 23 is the same as that of the previous embodiment. That is, first,
The insulating sheet 11 is disposed and adhered onto the group of central inner leads 8B so that its edges are perpendicular to the gap L8a between the divided portions 18 and 18. Next, the pellets 14 are adhered onto the insulating sheet 11. Subsequently, a wire 15 is bridged between the pad of the pellet 14 and the bonding portion 9 of the inner lead 8. After that, the resin-sealed package 16
is molded so that the insulating sheet 11, pellet 14, inner lead 8, and wire 15 are sealed with resin.

According to this embodiment, by dividing the inner lead wired directly under the pellet in the width direction, the width can be suppressed without reducing the overall cross-sectional area of the lead. The stress between the leads can be reduced without reducing the strength and the strength with which the leads are fixed by the resin, and as a result, the occurrence of resin cracks between the leads can be prevented.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the above-mentioned Examples (although various changes can be made without departing from the essential points). Needless to say.

For example, the central inner lead may be divided not only into two, but also into three or more. However, if the width of the gap between the plurality of divided parts is narrow, the stress in the resin in that part becomes high, making it easier for cracks to occur. In order to prevent cracks from occurring, it is desirable to provide as wide a gap as possible between the individual narrow parts of the divided parts, and at the very least, it is desirable to provide a gap with a width equal to or greater than the plate thickness of the lead. is necessary.

The shape of the divided parts of the central inner lead is not limited to the parallel straight lines as shown in the figure, but may be bent in the middle or the width may be changed in the middle. The length of the divided portion may be the same as or slightly shorter than the width of the gap.

In the part where the central inner lead 8B passes directly under the upper end of the pellet 14 on the side of the bonding part 9B, the width of the inner lead 8B can be made as narrow as desired regardless of the lead fixing strength. There is no need to divide it in the width direction as in .

In addition, it is not necessary to divide the central inner lead for all inner leads, but only for leads that are under particularly severe stress conditions, such as the lead directly below the center on the side of the pellet. Good too.

The directions in which the leads are drawn out of the package are not limited to two directions as shown in FIG. 23, but may be in the {circle around (2)} direction, or in three or more directions. Also,
The leads may be drawn out not only from the side of the package but also from the top or bottom of the package.

Further, although FIG. 23 shows an example in which the outer leads are bent downward outside the package, the leads outside the package may be bent in any direction or shape, or may not be bent.

If there is a dimensional margin between the outer shape of the resin-sealed package and the end of the pellet, or if the leads are pulled out from four directions of a package with a quadrilateral outer shape, connect the bonding wires as shown in Figure 27. It may also be done on the lead external drawer side of the pellet as shown in . in this case,
The wire 15 is connected to the inner lead 8 only to one of the parts 18 and 18 that are divided into a plurality of parts, as shown in FIG. The process may be performed repeatedly on a plurality of books, or may be performed on undivided portions.

In both Fig. 23 and Fig. 27, tabs are eliminated,
A structure is shown in which the pellet is supported only by the lead group. However, if this embodiment has a structure in which a part of the lead is disposed directly below the pellet, it is possible to
This is also effective in the case of a structure in which tabs are used together, as described in Japanese Patent No. 18139. Further, as described in Hiroma Publication and Japanese Unexamined Patent Publication No. 61-218139, either the circuit-forming surface or the non-circuit-forming surface of the pellet may be directed toward the lead side.

The insulating layer between the pellet and the lead may be formed not only by the film-like insulating sheet 11 but also by forming an oxygen film on the upper surface of the lead or the lower surface of the pellet, or by applying an electrically insulating coating. It is also effective to use an insulating adhesive as the adhesive.

In addition, the area to be insulated does not have to cover the entire bottom surface of the pellet, and may be limited to only the part where the pellet and the lead contact, or by partially inserting an insulating sheet to remove a part of the bottom surface of the pellet. A gap may be provided between the top surface and the top surface.

FIG. 28 is a perspective view of a lead portion that is a modification of this embodiment, with the upper portion of the lead removed. The divided portions 8 do not need to be connected on both sides of the divided portion to form a closed loop, but may remain divided and extend below the pellet 14 as shown in FIG. .

FIG. 29 is a perspective view showing a lead portion as another modification. The total width of the individual divided portions 18 of the lead 8 does not necessarily have to be smaller than the maximum width of the lead 8 outside the package 16. As shown in FIG. 29, if the individual widths of the divided portions 18 of the lead 8 are narrow and are spaced apart from each other with a sufficient distance, even if the total width is wider than the external lead width, It has the effect of preventing tarawaku and can provide strong lead strength and fixing strength.

FIG. 30 is a perspective view showing a lead portion as yet another modification. As the size of the pellet 14 increases, the edge of the pellet 14 approaches the side edge of the package 16, and the thermal stress generated by the pellet is applied not only to the bottom edge of the pellet but also to the area between the package side edge and the pellet edge. It will have a strong effect on the whole. Especially package 1
At the side ends of 6, the adhesive interface between the leads and the resin is likely to peel off due to cutting and molding of the outer leads 7 after resin molding, and as in the case of the lower end of the pellet, high stress concentration occurs in the resin between adjacent leads. easy. As in the embodiment shown in FIG. 30, if the lead division just below the bottom end of the pellet 14 is extended to the outside of the package 16, even if the end of the pellet is close to the side edge of the package 16, the adjacent This can prevent resin cranks between the leads.

FIG. 31 is a perspective view showing a lead portion as yet another modification. The stress acting on the resin part in the region between the bottom end of the pellet and the package side end is particularly high at the bottom end of the pellet and the package side end, as shown in FIG. , divided part 1
8, (2) A portion 18b may be provided to connect the 8s to each other, and the leads may be divided into a plurality of independent locations in the width direction. In this case, the stress concentration generated by the connecting portion 18b is reduced as the width of the connecting portion 18b becomes narrower, as in the case of the divided portion 18. The following is desirable. However, the width of the connecting portion 18b here refers to the width measured in the direction perpendicular to the width direction of the lead.

FIG. 32 is a perspective view showing a lead portion as yet another modification. The bent part of the outer lead 7 is the package 16
If the lead width of the lead bent portion 7a is wider than the total lead width of the side end of the package 16, as in the embodiments shown in FIGS. 30 and 31, During lead molding, the large force required to bend the wide part acts on the narrow lead at the end of the package 16, so the adhesive interface between the lead and the resin part and the resin part around the lead may be damaged. It's easy to accept. As shown in FIG. 32, by further extending the lead division beyond the lead bending portion 7a, damage to the vicinity of the lead-resin adhesive interface during lead molding can be prevented.

FIGS. 33 and 34 are perspective views showing still another modification of the lead portion. The stress applied to the resin parts between adjacent parts is greater at the lower end of the pellet 14 than at the side end of the resin part. In addition, in order to ensure lead strength and lead fixing strength, it is desirable to make the lead width near the side end of the package 16 as wide as possible. Therefore, the width of each divided portion 18 of the lead 8 is By changing the width gradually as shown in the example shown in the figure or stepwise as shown in the example shown in FIG. This method can improve the lead strength and lead fixing strength without impairing the resin crack prevention effect. It is also effective when performing it inside the package up to the vicinity of the side edge.

Furthermore, as illustrated in FIG. 35, the dividing portion 19 of each lead
may be composed of a plurality of wires; in short, it is sufficient that the sealing resin enters into the lead dividing portion.

(Embodiment 3) FIG. 36 is a plan sectional view showing another embodiment of the present invention,
FIG. 37 is a front sectional view thereof, and FIGS. 38 to 40 are explanatory diagrams for explaining its operation.

In this embodiment, the insulating sheet LLA interposed between the pellet 14 and the group of central inner leads 8B wired directly below it has a dimension on its short side that is the same as the dimension on the short side of the pellet 14. It is designed to be smaller than the

By the way, in a conventional resin-sealed package in which a pellet is fixed to an inner lead group wired in the center via an insulating sheet, and the dimensions of the insulating sheet are larger than the dimensions of the pellet, When this package is subjected to a temperature cycle, cracks C1 and C2 may occur inside the package, as shown in FIGS. 38 and 39.

The reason why cracks CI occur from the edges of the insulating sheet is that the insulating sheet is soft (film) and does not share much of the stress. This is because thermal stress due to the difference in linear expansion coefficients concentrates, causing fatigue failure of the resin part.

Further, the resin crack C1 that occurs between the leads 8 and 8 is caused by stress concentration at the lead corner portion. One of the causes of this crack generation is that the stress between the leads is increased by the crack C1 generated from the corner portion of the insulating sheet. Therefore, the crank C2 at the lead corner is the crank C1 from the insulating sheet corner.
It is a subordinate rack.

In a resin-sealed package with the above configuration, the thermal fatigue life can be reduced to about 1/10 compared to a normal package in which the pellet is fixed to the tab of the lead frame, and reliability is lowered. It wasn't always satisfying. For this reason, there has been a demand for improvement in reliability through temperature cycling and the like.

This embodiment solves this problem by making the dimension of the short side of the electrical insulator smaller than the dimension of the short side of the element.

Next, the action will be explained.

FIG. 40 is a diagram showing changes in stress generated in the sealing resin portion of the resin sealing package when the dimensions of the pellet are constant and the dimensions of the insulating sheet are changed.

As can be understood from Fig. 40, in the conventional structure where X>o, excessive stress occurs due to stress concentration at point a at the end of the insulating sheet, causing cracks. . Here, X is a value given by the following equation.

X-(insulating sheet size-pellet size)/2 As the value of X becomes smaller, the stress at point a of the insulating sheet decreases slightly. This is because the distance Nd between the insulating sheet and the package end increases as the value of X decreases. However, it does not drop to the point where resin cranking does not occur.

As shown in Figure 40, when the insulating sheet size is smaller than the pellet size (X becomes a negative value), a
The stress concentration at a point decreases discontinuously, and there is almost no stress concentration. Conversely, at this time, the stress at the end of the pellet increases, but if no separation occurs between the resin part and the pellet, the generated stress is not so high and can be suppressed to a level that does not cause cracks.

Therefore, in such a case, for example, a resin that has good adhesion to the material constituting the pellet may be selected.

Comparing the case where X = +IQOμm in the conventional structure and the case where x = -100tIm in this embodiment, the generated stress is
As shown in FIG. 0, the stress σ1 in the conventional case is σ2, and the stress σ2 in the present example is approximately 40% lower than the stress σ in the conventional product.

Note that even if the short side dimension of the insulating sheet is made smaller by about 100 μm than the short side dimension of the element, no inconvenience will occur in terms of manufacturing.

According to this embodiment, by making the short side dimension of the insulating sheet between the pellet and the central inner lead smaller than the short side dimension of the pellet, the resin part generated at the end of the insulating sheet can be reduced. Since stress concentration can be extremely reduced, it is possible to prevent resin cracks from occurring from the ends of the insulating sheet.

FIG. 41 is an enlarged partial vertical cross-sectional view showing a modification of this embodiment, in which a step 19 is arranged in the central inner lead 8B at a position substantially facing the outer edge of the insulating sheet 11A, and is formed downward. This step 19 increases the distance e between the lower surface of the pellet and the upper surface of the lead.

The effect will be explained with reference to FIGS. 42 and 43. FIG. 42 shows a partial cross-sectional view of the tablez package, and FIG. 43 shows the resin stress distribution at the Z-2 section in the figure. The resin stress is highest on the side surface of the pellet, and decreases rapidly as the distance from the pellet increases in the package thickness direction. Therefore, by adding a step to the lead, the resin stress near the top surface of the lead decreases from σ3 to σ4 as shown in Figure 43, thereby preventing the occurrence of resin cracks from the lead. can.

FIG. 44 is an enlarged partial sectional view showing another modification, in which, in addition to the structure shown in FIG. 41, a groove is carved on the outer circumference of the beret t-m plane. As a result, the pellet and the resin are stably fixed, so that stress concentration in the resin at the end of the pellet due to peeling between the pellet and the resin portion can be prevented.

[Effects of the Invention] The effects obtained by typical inventions disclosed in this application are briefly explained as follows.

In a semiconductor device equipped with a resin-sealed package in which a pellet is fixed to the inner lead via an insulating layer, the adhesive strength between the lead and the sealing resin part can be increased, and the stress between the leads can be increased. It is also possible to reduce the stress concentration in the sealing resin part that occurs at the end of the insulating layer, so it is possible to prevent the package from cracking due to temperature cycling.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a DILP/IC which is an embodiment of the present invention, FIG. 2 is a side view and central vertical sectional view, and FIG. 3 is a front view and central cross-sectional view. FIG. 4 to FIG. 11 show a DILP-1 which is an embodiment of the present invention.
Figure 4 is a partially omitted plan view showing the multi-lead frame used in the IC manufacturing method, and Figures 5 and 6 are plan views showing the insulating sheet, pellets, and wires after bonding. 7 is a plan view showing the circuit layout of the pellet; FIG. 8 is a plan view showing the pad layout of the pellet; FIG. 9 is a longitudinal sectional view showing the molding process of the resin-sealed package; FIG. 10 is a partially omitted plan view, and FIG. 11 is a partially omitted plan view showing the multi-lead frame after molding the resin-sealed package. FIG. 12, FIG. 13, and FIG. 14 are diagrams for explaining the operation. Figure 15, Figure 16, Figure 17, Figure 18, Figure 19,
FIGS. 20, 21, and 22 are enlarged partial perspective views showing modifications of this embodiment, respectively. FIG. 23 shows another embodiment of the present invention.
A partially cutaway perspective view of the IC, FIGS. 24, 25, and 26 are explanatory diagrams for explaining its functions. FIG. 27 is a partially cutaway perspective view showing a modification of the second embodiment; FIGS. 28, 29, 30, 31, 32,
33, 34, and 35 are perspective views of the lead portion showing other modified examples, respectively. FIG. 36 is a plan sectional view showing another embodiment of the present invention. FIG. 37 is a front sectional view thereof, and FIGS. 38, 39, and 40 are explanatory diagrams for explaining its operation. Fig. 41 is an enlarged partial longitudinal cross-sectional view showing a modification of the third embodiment; Figs. 42 and 43 are explanatory diagrams for explaining its operation; Fig. 44 is an enlarged partial longitudinal cross-sectional view showing another modification. It is a front view. 1...Multiple lead frame, 2...Unit lead frame, 3...Outer frame, 4...Section frame, 5...
Dam member, 5a...Dam, 6...Lead, 7...
Outer lead (outer part), 8... Inner lead, 8
A...Peripheral inner lead, 8B...Central inner lead, 9.9A, 9B...Wire bonding part,
10,10A~IOF...through hole, IOG...rib, 11...insulating sheet, 12.13...bonding layer, 14...berent, 15...bonding wire, 16... Resin sealed package, 17...DI
LP-IC (semiconductor device U), 18... division part, 18a
...Gap, 19...Step.

Claims (1)

[Claims] 1. A semiconductor pellet, a plurality of leads that are electrically independent from each other and each constitute an external terminal, and a bridge between the inner part of each lead and the semiconductor pellet, respectively. and a package for resin-sealing the semiconductor pellet, the inner part of the lead, and the bonding wire, and at least some of the leads in the lead group have a part of the inner part in the package. In a semiconductor device, the leads are wired below the semiconductor pellet within the semiconductor pellet, and an insulating layer is interposed between the inner group and the semiconductor pellet. At least some of the leads have through-holes that extend across the boundary line in the inner and outer directions to increase the occupied area ratio of the resin portion at the boundary line facing the outer edge of the semiconductor pellet of the lead. A semiconductor device characterized by being opened. 2. The semiconductor device according to claim 1, wherein the through hole extends outside the package to a bent portion in an outer portion of the lead. 3. The first aspect of the present invention is characterized in that the through hole extends outside the package to a position that is closer to the inside than the bent portion of the outer portion of the lead.
1. Semiconductor device described in Section 1. 4. Claim 2 or 3, characterized in that the portion of the through hole extending outward of the package is formed to have a narrower width than the inner portion of the package.
1. Semiconductor device described in Section 1. 5. The semiconductor device according to claim 1, wherein an end of the through hole is located inside the package. 6. The semiconductor device according to claim 1, wherein the wire bonding portion group of the lead is unevenly distributed in a position facing the short side of the semiconductor pellet within the package. . 7. A semiconductor pellet, a plurality of leads that are electrically independent from each other and each constitute an external terminal, and a bonding wire that is bridged between the inner part of each lead and the semiconductor pellet, The package includes a package for resin-sealing the semiconductor pellet, the inner part of the lead, and the bonding wire, and at least some of the leads in the lead group have a part of the inner part of the semiconductor pellet inside the package. In a semiconductor device in which the leads are wired downwardly, and an insulating layer is interposed between the inner part group and the semiconductor pellet, at least some of the leads of the lead group wired below the semiconductor pellet. A semiconductor device characterized in that the leads are branched into a plurality of leads in the width direction of each lead so as to reduce stress between the leads at least in a portion corresponding to the periphery of the lower surface of the semiconductor pellet. 8. The semiconductor device according to claim 7, wherein the branch portion of the lead is constituted by a plurality of wire rods. 9. A semiconductor pellet, a plurality of leads that are electrically independent from each other and each constitute an external terminal, and a bonding wire that is bridged between the inner part of each lead and the semiconductor pellet, The package includes a package for resin-sealing the semiconductor pellet, the inner part of the lead, and the bonding wire, and at least some of the leads in the lead group have a part of the inner part of the semiconductor pellet inside the package. In a semiconductor device in which wiring is arranged below and an insulating layer is interposed between the inner part group and the semiconductor pellet, the insulating layer is formed of an insulating sheet formed in a rectangular sheet shape. and a short side dimension of the insulating sheet is set smaller than a short side dimension of the semiconductor pellet. 10. The insulating sheet is provided with a step near the end of the short side, and the outer side of the insulating sheet in the lead group is lowered from the adhesive end, thereby increasing the distance between the semiconductor pellet and the surface of the lead group. The semiconductor device according to claim 9, characterized in that it is formed as follows. 11. The semiconductor device according to claim 10, wherein a groove is formed on the back surface of the semiconductor pellet so as to be located outside the outer edge of the short side of the insulating sheet. 12. A part of the inner part of at least some of the leads in the group of leads is wired to the empty space in the center, and at least part of the inner part has a through hole extending in the longitudinal direction. a step of preparing a lead frame which is opened as shown in FIG. A step of bonding a semiconductor pellet onto an insulating sheet, a step of bridging a bonding wire between the semiconductor pellet and each of the wire bonding parts of the lead group, and a step of bonding the semiconductor pellet, the inner part of the lead, and bonding. 1. A method of manufacturing a semiconductor device, comprising the step of resin-molding a package for resin-sealing a group of wires.