JP2000286379A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) Abstract: The present invention relates to a semiconductor device having a structure in which a semiconductor chip mounted on a die pad is sealed with a resin, and a method for manufacturing the same. The task is to achieve this. The semiconductor device includes a semiconductor chip, a die pad on which the semiconductor chip is mounted via a die attaching material, and a resin package for sealing at least the semiconductor chip and the die pad. A joining force increasing portion 30A including a through portion 31A and a step portion 32A is formed in 23A. The step portion 32A constituting the joining force increasing portion 30A is formed within the thickness range of the die pad 23A. Further, with the semiconductor chip 22 mounted on the die pad 23A, a gap 40 is provided between the semiconductor chip 22 and the step portion 32A.
Is formed, and a part of the resin package 27 is also interposed in the gap 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device having a structure in which a semiconductor chip mounted on a die pad is sealed with a resin and a method of manufacturing the same. In recent years, semiconductor devices have been reduced in size and thickness, and accordingly, the wall pressure of a resin package has tended to decrease. As a result, the mechanical strength of the package is reduced, and the difference in thermal expansion between the die pad on which the semiconductor chip is mounted and the resin package during application of heat such as reflow processing during mounting, and water vapor generated at the interface between the die pad and the resin package As a result, peeling may occur between the die pad and the resin package, and swelling may occur on the back surface of the resin package.

Therefore, a semiconductor device which is resistant to thermal stress and can maintain high reliability even when heat is applied is desired.

[0003]

2. Description of the Related Art In general, a semiconductor device having a structure in which a semiconductor package is formed by attaching a semiconductor chip to a die pad of a lead frame by die bonding on a die pad of the lead frame, and then performing resin molding after resin bonding is known. I have. In a semiconductor device having this resin package, when the resin absorbs moisture, when heated during mounting, water vapor is generated at the interface between the resin package and the die pad, and peeling occurs between the resin package and the die pad, or Swelling may occur on the back surface of the resin package.

[0004] Further, since the resin package and the die pad have different coefficients of thermal expansion, there is a possibility that peeling may occur between the resin package and the die pad due to the difference in thermal expansion during heating. Further, as a material of the die pad, a copper alloy, which is a lead frame material, is widely used in order to meet demands for thinner and higher performance. However, since a copper alloy has poor adhesion to a resin, when a die pad made of a copper alloy is used, peeling may occur between the resin package and the die pad due to the poor adhesion.

Conventionally, as means for preventing the occurrence of peeling or swelling, changing the shape of the interface of the die pad to be bonded to the resin package has been performed. 1 to 6 show specific examples of conventional means for preventing the occurrence of peeling or swelling. The example shown in FIG. 1 and FIG.
At the interface where the die pad 3A is bonded to the resin package 7,
Dimples 8 (hemispherical concave portions) are formed.
FIG. 1 shows a semiconductor device 1A having a die pad 3A on which dimples 8 are formed, and FIG. 2 shows a semiconductor device 1A.
Shows a lead frame 10A used in manufacturing the lead frame.

According to this structure, since the dimple 8 is cut into the resin package 7, the die pad 3
The bonding strength between A and the resin package 7 is improved, so that separation between the die pad 3A and the resin package 7 can be prevented, and swelling of the resin package 7 can be prevented. 3 and 4, the slit 9 is formed in the die pad 3B, and the resin package 7 is also interposed in the slit 9. FIG. 3 is an enlarged view of a main part of a semiconductor device 1B having a die pad 3B in which a slit 9 is formed, and FIG.
4B shows a lead frame 10B used when manufacturing B.

According to this configuration, since the plurality of slits 9 disperse the stress generated in the die pad 3B when heat is applied, the stress directly acting on the interface between the die pad 3B and the resin package 7 is reduced. Therefore, separation between the die pad 3C and the resin package 7 can be prevented, and swelling of the resin package 7 can be prevented. Further, in the examples shown in FIGS. 5 and 6, the die pad 3C is configured to be smaller than the semiconductor chip 2. That is, the length of the die pad 3C is L1, and the semiconductor chip 2
When the length is L2, L1 <L2. FIG. 5 shows that the die pad 3C is connected to the semiconductor chip 2.
The main part of the semiconductor device 1C, which is smaller than the main part, is shown in an enlarged manner, and FIG. 6 shows a lead frame 10C used when manufacturing the semiconductor device 1C.

According to this configuration, FIGS.
Since the bonding area between the die pad 3C and the resin package 7 is smaller than that of the configuration described above, the stress generated between the die pad 3C and the resin package 7 is also smaller, so that peeling between the die pad 3C and the resin package 7 can be prevented. In addition, the occurrence of swelling of the resin package 7 can be prevented.

In FIGS. 1 to 6, reference numeral 4 denotes a die attaching material for joining the semiconductor chip 2 to the die pads 3A to 3C, and reference numeral 5 denotes a lead functioning as an external connection terminal.
Reference numeral 6 denotes wires for electrically connecting the semiconductor chip 2 and the leads 5.

[0010]

1 and 2 described above.
Although it is necessary to form a plurality of dimples 8 on the die pad 3A in the means described with reference to FIG.
Is formed by etching the die pad 3A. However, there is a problem in that the etching process is more expensive than the mechanical process, and the processing time is long and the throughput is poor.

In the means described with reference to FIGS. 3 and 4, the stress generated in the die pad 3B when heat is applied or the like is dispersed in the slits 9 to prevent peeling and swelling. The function of preventing swelling is weaker than that of the other means described above.
B and resin package 7 and resin package 7
There is a problem that the occurrence of swelling cannot be reliably prevented.

Further, the means described with reference to FIGS. 5 and 6 has a problem that the heat radiation efficiency of the semiconductor device 1C is reduced. That is, the die pad 3C functions as a stage on which the semiconductor chip 2 is mounted, and also functions as a heat radiating plate for radiating heat generated in the semiconductor chip 2. However, when the size of the die pad 3C is reduced, the function as a heat radiating plate is reduced, so that the heat radiation efficiency of the semiconductor device 1C is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a semiconductor device capable of improving the bonding property between a die pad and a resin package while maintaining a reduced thickness, and a method of manufacturing the same. I do.

[0014]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by taking the following means. 2. The semiconductor device according to claim 1, wherein the semiconductor device includes a semiconductor chip, a die pad on which the semiconductor chip is mounted via a die attaching material, and a resin package for sealing the semiconductor chip and the die pad. A bonding force increasing portion formed by a penetrating portion penetrating the die pad, and a step portion formed within a thickness range of the die pad and formed to have a gap between the semiconductor chip. A part of the resin package is also interposed in a gap between the semiconductor chip and the step.

According to a second aspect of the present invention, in the semiconductor device according to the first aspect, a part of the resin package is formed so as to surround the step portion. According to a third aspect of the present invention, in the semiconductor device according to the first or second aspect, a plurality of the joining force increasing portions are formed, and the arrangement position is set at a position symmetrical with respect to a center of the die pad. It is characterized by having been set.

[0016] Further, the invention according to claim 4 is characterized in that:
A lead frame forming step of forming a lead frame having at least a lead and a die pad, and after mounting a semiconductor chip on the lead frame, disposing a resin so as to seal at least the semiconductor chip and the die pad; In the method for manufacturing a semiconductor device having a package forming step of forming, in the lead frame forming step, a penetrating portion penetrating the die pad, and formed within a thickness range of the die pad and with respect to the thickness of the die pad A gap in which a bonding force increasing portion including a step portion having a small thickness is collectively formed on the die pad, and the resin is formed between the semiconductor chip and the step portion in the package forming step. It is characterized in that it is configured to be introduced into a department.

According to a fifth aspect of the present invention, in the method of manufacturing a semiconductor device according to the fourth aspect, in the lead frame forming step, the lead, the die pad, and the bonding force increasing portion are formed using a press working method. It is characterized by forming. According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to the fifth aspect, when the bonding force increasing portion is formed in the lead frame forming step, the through portion is first punched out, and then the The step portion is formed by crushing a position corresponding to the step portion.

According to a seventh aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor chip; a die pad on which the semiconductor chip is mounted via a die attaching material; and a resin package for sealing the semiconductor chip and the die pad. In the apparatus, the die pad is formed so as to have a slit-shaped penetrating portion penetrating the die pad, and to have a thickness within the thickness range of the die pad in the penetrating portion and to have a gap between the semiconductor chip. A joining force increasing portion formed by a plurality of stepped portions provided so that a part of the resin package is interposed also in a gap between the semiconductor chip and the stepped portion. Things.

Each of the above means operates as follows.
According to the first, second, and fourth aspects of the present invention, the bonding force formed by the penetrating portion penetrating the die pad and the step portion formed to have a gap between the semiconductor chip and the semiconductor chip is increased. By providing the portion on the die pad, the resin is introduced into the through portion and into the gap between the semiconductor chip and the step portion when forming the resin package.

As described above, since a part of the resin package is also interposed in the gap between the semiconductor chip and the step, the resin package has a structure surrounding (enclosing) the step. The bonding strength between the package and the die pad can be improved. Therefore, even if heat is applied during mounting or the like, peeling at the interface between the resin package and the die pad and swelling occurring on the back surface of the resin package can be prevented, and the reliability of the semiconductor device can be improved.

Further, since the step portion is formed within the thickness range of the die pad, the die pad does not become thick even if the step portion is provided. Therefore, high reliability can be realized while keeping the semiconductor device thin. Also,
According to the third aspect of the present invention, the arrangement positions of the plurality of joining force increasing portions are symmetric with respect to the center of the die pad, so that heat is applied to the semiconductor device and each joining force increasing portion is applied. Is applied, the stress applied to each joining force increasing portion is substantially uniform. That is, since the stress is not applied unevenly, peeling of the die pad from the resin package and swelling of the resin package can be more effectively prevented.

According to the fifth aspect of the present invention, in the lead frame forming step, the lead, the die pad, and the joining force increasing portion are formed by using a press working method, so that the joining force increasing portion is formed between the lead and the die pad. The lead frame can be formed simultaneously with the formation, and the lead frame can be formed easily and efficiently.

According to the invention, when forming the joining force increasing portion in the lead frame forming step, the through portion is first punched out, and then the position corresponding to the step portion is crushed. By forming a step,
The deformation (extension) of the step portion generated when the step portion is crushed is released to the through portion. Therefore, generation of distortion or warpage in the die pad can be prevented, and the flatness of the die pad can be maintained.

According to the seventh aspect of the present invention, the bonding force increasing portion provided on the die pad is formed so as to have a gap between the slit-shaped through portion penetrating the die pad and the semiconductor chip. When the resin package is formed, the resin is introduced into the penetrating portion and into the gap between the semiconductor chip and the step portion by forming a plurality of step portions in the portion.

As described above, since a part of the resin package is interposed also in the gap between the semiconductor chip and the step, the resin package has a structure surrounding (enclosing) the step. The bonding strength between the package and the die pad can be improved. Therefore, even if heat is applied during mounting or the like, peeling at the interface between the resin package and the die pad and swelling occurring on the back surface of the resin package can be prevented, and the reliability of the semiconductor device can be improved.

At this time, since the penetrating portion has a slit-like shape, a wide portion through which the resin can pass even if the inside has a step portion, and the flow resistance of the resin filled in forming the resin package is small. Thus, resin filling can be facilitated. On the other hand, if heat treatment (for example, heat treatment for mounting) is performed after the resin package is formed,
Stress is generated in the die pad due to the difference in thermal expansion between the die attach material and the resin package. By forming a through portion formed in the die pad into a slit shape, the through portion can have a stress relaxation function. Therefore, the stress generated due to the difference in thermal expansion can be reduced at the through portion. Thereby, even if the heat treatment is performed after the formation of the resin package, it is possible to prevent the separation from occurring between the die attaching material and the die pad.

That is, by forming the penetrating portion in a slit shape and forming a step portion in the inside thereof, the peeling at the interface between the resin package and the die pad and the swelling on the back surface of the resin package are formed in the same manner as in the above-mentioned inventions. Can be prevented, and further, separation prevention at the interface between the die attach material and the die pad can be realized together.

[0028]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a longitudinal sectional view of a semiconductor device 20A according to the first embodiment of the present invention. As shown in the figure, the semiconductor device 20A is roughly the semiconductor chip 2
2, a die pad 23A, a lead 25, a wire 26, a resin package 27, and the like.

The semiconductor chip 22 is bonded (mounted) to a die pad 23A using a die attaching material 24. A plurality of leads 25 are formed at an outer peripheral position of the semiconductor chip 22.
Are electrically connected to each other. As described later, the die pad 23 and the lead 25 are connected to a lead frame 36 (FIG. 9).
(B)), and the material is, for example, a Cu—Ni—Sn-based copper alloy (Fe—N
i alloy can also be applied). Further, since the semiconductor device 20A according to the present embodiment is, for example, a surface-mount type QFP (Quad Flat Package), the outer lead portion of the lead frame 36 is formed in a gull-wing shape.

The resin package 27 is made of, for example, an epoxy resin, and has a function of sealing the semiconductor chip 22, the die pad 23A, the leads 25 (inner lead portions), and the wires 26, and protecting them. Also,
The thickness of the semiconductor device 20A according to the present embodiment is reduced, and thus the thickness of the resin package 27 is reduced as much as possible.

Specifically, the thickness of the resin package 27 is set to 1.4 mm or less. Therefore, in the semiconductor device 20A thus thinned, the strength and rigidity of the resin package 27 are reduced to some extent as compared with the conventional semiconductor device having a large thickness. Here, attention is paid to the die pad 23A which is a main part of the present invention, and it will be described in detail below with reference to FIGS. 9B, 10 and 11 in addition to FIG. FIG. 9 (B) is a view showing a lead frame 36 used when manufacturing the semiconductor device 20A, and FIG.
FIG. 11 is an enlarged view of FIG. 0A, and FIG. 11 is a sectional view of the die pad 23A before the resin package 27 is formed.

As shown in FIG. 9B, a plurality of bonding force increasing portions 30A are formed on the die pad 23A provided on the semiconductor device 20 according to the present embodiment. As shown in FIG. 10, the joining force increasing portion 30A has a through portion 31A.
And a step portion 32A. Penetration part 31
A is a hole formed so as to vertically penetrate the die pad 23A.

In this embodiment, as shown in FIG. 10B, the step portion 32A is formed to have a cross shape in a plan view, and as shown in FIG. The thickness W2 is formed within the range of the thickness W1 of the die pad 23A (that is, W1> W2). The lower surface of the step portion 32A according to the present embodiment has a die pad 32A.
Is formed so as to be flush with the lower surface of the
A gap 40 indicated by a dimension W3 (W3 = W1−W2) is formed above 2A. That is, the step portion 32A has a step with respect to the upper surface (the surface on which the semiconductor chip 22 is mounted) of the die pad 23A.

As described above, since the step portion 32A is formed within the range of the thickness W1 of the die pad 23A, the step portion 32A does not protrude from the die pad 23A. Therefore, even if the step portion 32A is provided on the die pad 23A, the die pad 23A does not become thicker.
Therefore, the semiconductor device 20A can be kept thin.

Subsequently, the joining force increasing portion 3 having the above-described structure is used.
Attention is paid to the bonding state between the die pad 23A having 0A and the resin package 27. When the resin package 27 is formed by providing the die pad 23A with a bonding force increasing portion 30A including a penetrating portion 31A penetrating the die pad 23A and a step portion 32A having a gap 40 on the upper portion, the resin package 27 is formed by the penetrating portion 31A. And the step portion 32
It is also interposed in the gap 40 above A (hereinafter, in the resin package 27, a portion interposed in the gap 40 in particular is referred to as an interposed resin portion 33).

In this embodiment, when the semiconductor chip 22 is mounted on the die pad 23A, the semiconductor chip 22 is mounted on the side where the gap 40 is formed. Therefore, as shown in FIG.
Has an upper part in contact with the semiconductor chip 22 and a lower part surrounding (enveloping) the step 32A. That is, the resin package 27 has a configuration surrounding (enveloping) the step 32A, and thus the bonding strength between the resin package 27 and the die pad 23A can be improved.

As a result, even if heat is applied to the semiconductor device 20A during mounting or the like, separation occurs at the interface between the resin package 27 and the die pad 23A,
Further, even if the absorbed moisture becomes steam, the resin package 2
7 can be prevented from occurring on the back surface, and the reliability of the semiconductor device 20A can be improved. In particular, even when a copper alloy having low bonding property with the resin package 27 is used as the material of the die pad 23A as in the present embodiment, the bonding property between the die pad 23A and the resin package 27 is high as described above. And die pad 23A
There is no occurrence of delamination between them.

The resin package 27 and the die pad 2
Since the bonding property with 3A is high, the area of the die pad 23A can be increased. Therefore, the die pad 23
The thermal resistance of A is reduced, and the heat generated in the semiconductor chip 22 can be efficiently radiated. Further, in this embodiment, as shown in FIG. 9B, the arrangement positions of the plurality of bonding force increasing portions 30A formed on the die pad 23A are configured to be symmetric with respect to the center position of the die pad 23A. I have. Thereby, even when heat is applied to the semiconductor device 20A during mounting or the like and stress is generated in each of the joining force increasing portions 30A, the stress applied to each of the joining force increasing portions 30A can be made substantially uniform. Accordingly, the stress is not biased and applied to the bonding force increasing portion 30A, and the die pad 23A
Of resin and resin package 27, and resin package 2
7 can be prevented more effectively.

FIG. 8 shows the semiconductor device 20A shown in FIG.
Shows a semiconductor device 20B which is a modification example of FIG. The semiconductor device 20B has a configuration in which the leads 25 are bonded to the die pad 23B using an adhesive 34. In this configuration, in order to further improve the heat radiation characteristics of the die pad 23B, the die pad 2 of the semiconductor device 20A according to the first embodiment is used.
The area is set wider than 3A. Also,
In this modification, the lead 25 and the die pad 23B are formed separately, so that a material suitable for each function can be selected.

Next, a method of manufacturing a semiconductor device according to an embodiment of the present invention will be described with reference to FIGS. In the following description, the method for manufacturing the semiconductor device 20A according to the first embodiment described above will be described as an example. In FIGS. 9 to 13, components corresponding to the components shown in FIG. 7 will be described with the same reference numerals.

Further, as is well known, the semiconductor manufacturing process includes a number of processes. The present invention is characterized by a lead frame forming process for forming a lead frame and a package forming process for forming a resin package. Since there is no difference from the related art, these two steps will be mainly described, and the description of the other steps will be omitted. 9 and 10 are views for explaining a lead frame forming process. To manufacture the semiconductor device 20A, first, FIG.
A base material 35 shown in (A) is prepared. The base material 35 is made of a copper alloy (Fe-Ni, for example, MF-202, EFTEC-64, etc.).
Alloy is also applicable), which is the same as that generally used as a lead frame base material for a semiconductor device.

The base material 35 is subjected to press working,
The lead frame 36 shown in FIG. 9B is formed. The lead frame 36 includes a plurality of leads 25 that are wire-bonded to the semiconductor chip 22 and a die pad 23A on which the semiconductor chip 22 is mounted and die-attached.
And a support bar 3 supporting the die pad 23A.
8, a positioning hole 39 used for positioning, and a bonding force increasing portion 30A for improving bonding between the resin package 27 and the die pad 23A as described above. In the state of the lead frame 36, each lead 25 is fixed by a diver 37.

In this embodiment, the joining force increasing portion 30A is formed in the lead frame forming step by using a pressing method to form the lead 25, the die pad 23A, and the support bar 3A.
8, and simultaneously with the formation of the positioning holes 39. As described with reference to FIG. 10, the joining force increasing portion 30A is formed by the through portion 31A and the step portion 32A.
Since it has a simple configuration, it can be formed using a press working method (mechanical processing).

Accordingly, it is not necessary to provide a separate step in forming the joining force increasing portion 30A, and the joining force increasing portion 3
OA can be formed easily, efficiently, and at low cost. The joining force increasing portion 30A can be formed by using another processing method such as etching. However, the pressing method (mechanical processing) can perform the processing at a lower cost and with higher efficiency. .

Further, it is not always necessary to simultaneously form the penetrating portion 31A and the step portion 32A which constitute the joining force increasing portion 30A. That is, when forming the bonding force increasing portion 30A in the lead frame forming step, first, a through portion 31A is punched out and formed, and then a position corresponding to the step portion 32A of the die pad 23A is crushed to form the step portion 32A. May be used.

By using this forming method, the deformation (extension) of the step portion 32A generated when the step portion 32A is crushed is released to the through portion 31A. Therefore, even if the bonding force increasing portion 30A is formed on the die pad 23A, it is possible to prevent the die pad 23A from being warped or warped, and to maintain the flatness of the die pad 23A. A predetermined plating process is performed on the lead frame 36 manufactured as described above, and then the die attaching material 2 is attached to the die pad 23A.
4, the semiconductor chip 22 is mounted. At this time, the die attaching material 24 is used as the bonding force increasing portion 30 of the die pad 23A.
It is arranged at the position except A. By arranging the die attaching material 24 except for the joining force increasing portion 30A in this manner, it is possible to prevent the die attaching material 24 from adhering to the penetrating portion 31A and the step portion 32A constituting the joining force increasing portion 30A. .

That is, when the die attaching material 24 adheres to the through portion 31A and the stepped portion 32A and fills them, the bonding force between the die pad 23A and the resin package 27 is sufficiently exhibited. Can not. However, by arranging the die attaching material 24 except for the joining force increasing portion 30A, the joining force between the joining force increasing portion 30A and the resin package 27 can be ensured. The joining force can be reliably improved.

When the semiconductor chip 22 is mounted on the die pad 23A as described above, a wire 26 is subsequently wire-bonded between the semiconductor chip 22 and the lead 25. Subsequently, the lead frame 36 on which the semiconductor chip 22 is mounted is mounted on a resin molding die (not shown), and a package forming step is performed. 11 to 13 are views for explaining a package forming process. In each figure, for convenience of explanation, the die pad 23A
Only the vicinity of is shown enlarged.

FIG. 11 shows the die pad 23A in a state before the resin 41 serving as the resin package 27 is filled. As described above, when the semiconductor chip 22 is mounted, the gap 40 indicated by the dimension W3 is formed between the step portion 32A and the semiconductor chip 22.
FIG. 12 shows a state where the resin 41 to be the resin package 27 is introduced (filled). As described above, the joining force increasing portion 30A includes the penetrating portion 31A and the stepped portion 3A.
2A, and the gap 40 above the step portion 32A communicates with the outside through the through portion 31A. Therefore, the resin 41
Is introduced, the resin 41 is also interposed inside the gap 40 to form the interposed resin portion 33.

FIG. 13 shows a state where the resin package 27 is formed. As shown in the figure, the interposition resin portion 33 which is a part of the resin package 27 is
A is surrounded (wrapped around) A, so that the bonding strength between the resin package 27 and the die pad 23A is improved.
Therefore, as described above, the semiconductor device 20 is mounted at the time of mounting or the like.
Even if heat is applied to A, separation at the interface between the resin package 27 and the die pad 23A can be prevented, and swelling on the back surface of the resin package 27 can be prevented even if the absorbed moisture becomes water vapor. , Semiconductor device 2
0A reliability can be improved.

14 to 20 show another embodiment of the joining force increasing portion. FIG. 14 shows a bonding force increasing portion 30B according to the second embodiment. FIG. 15 shows a semiconductor device 20C according to a second embodiment of the present invention, which is characterized by using a bonding force increasing portion 30B. The joining force increasing portion 30A described with reference to FIG.
Although 2A has a cross shape, the joining force increasing portion 30B of the present embodiment is characterized in that the step portion 32B is configured to extend in a cantilever shape into the through portion 31B. By applying the joining force increasing portion 30B, as shown in FIG. 15, the area of the penetrating portion 31B is widened, and the interposed resin portion 33 is surely introduced into the gap portion 40 and the step portion 32B
Is wrapped around. Thereby, the bonding strength between the resin package 27 and the die pad 23C can be further improved.

FIG. 16 shows a joining force increasing portion 30C of the third embodiment. Bonding force increasing portion 30C of this embodiment
Is characterized in that a step portion 32C is extended in a doubly supported manner into the through portion 31C. In the joining force increasing portion 30B having the cantilever-shaped step portion 32B shown in FIG. 14, when the thickness of the die pad 23C is small,
The step 32B may be deformed. When the step portion 32B is deformed as described above, the bonding strength between the resin package 27 and the die pad 23C may be reduced depending on the state of the deformation.

However, as in this embodiment, the step portion 32C
Is formed as a doubly supported beam, it is possible to prevent the deformation of the step portion 32C while maintaining the operation and effect of the joining force increasing portion 30C of the second embodiment described above. Therefore, the bonding strength between the resin package 27 and the die pad 23D can be maintained high. 17 to 19 show a bonding force increasing portion 30D according to a fourth embodiment. 17 is a plan view of the die pad 23E provided with the bonding force increasing portion 30D, FIG. 18 is a cross-sectional view along the line AA in FIG. 17, and FIG. 19 is an enlarged view of the bonding force increasing portion 30D. FIG.

In the bonding force increasing portion 30D according to the present embodiment, the penetrating portions 31D penetrating the die pad 23E are formed in a slit shape (a long hole shape), and a plurality of (four in this embodiment) are provided inside each penetrating portion 31D. ) Is formed. In the example shown in FIG. 17, four slit-shaped penetration portions 31D are formed in the die pad 23, and are arranged so as to form a cross shape.

Further, inside each slit-shaped through portion 31D, a step portion 32D is formed so as to extend alternately from the left and right into the through portion. The thickness of each step 32D is
It is set smaller than the thickness of the die pad 23E,
Therefore, each step 32D is formed at a position where a step is formed on the surface of the die pad 23 (see FIG. 18).

In the structure of this embodiment, as in the above-described embodiments, when forming the resin package 27 (not shown), the resin is filled in the through portion 31D and the semiconductor chip 22 (not shown). ) And the step 32D. Therefore, the resin package 27 surrounds (encloses) the step 32D, and the resin package 2
7 and the die pad 23E can be improved in bonding strength. Thereby, even if heat is applied during mounting or the like, separation at the interface between the resin package 27 and the die pad 23E and swelling generated on the back surface of the resin package can be prevented, and the reliability of the semiconductor device can be improved. it can.

When the resin is introduced into the penetrating portion 31D, the penetrating portion 31D has a slit-like shape. Therefore, the flow resistance of the resin filled at the time of forming the resin package is reduced, and the resin filling can be facilitated. On the other hand, if heat treatment (for example, heat treatment for mounting) is performed after the resin package is formed, stress is generated in the die pad 23E due to the difference in thermal expansion between the die attach material 24 (see FIG. 7) and the resin package 27. I do. However, in this embodiment, since the through portion 31D formed in the die pad 23E is formed in a slit shape, the through portion 31D is formed.
D has a configuration having a stress relaxation function.

That is, when a stress is applied to the die pad 23E, the penetrating portion 31D is deformed (the resin in the penetrating portion 31D is also flexibly deformed at this time), whereby the stress generated due to the difference in thermal expansion is caused. Is absorbed and relaxed by the through portion 31D. Thereby, even if the heat treatment is performed after the formation of the resin package, it is possible to prevent the separation from occurring between the die attaching material 24 and the die pad 23E.

Thus, similarly to the above-described embodiments,
It is possible to prevent peeling at the interface between the resin package 27 and the die pad 23E and to prevent swelling on the back surface of the resin package, and furthermore, in this embodiment, to prevent peeling at the interface between the die attach material 24 and the die pad 23E. And the reliability of the semiconductor device can be further improved.

FIG. 20 is a plan view of a die pad 23F according to a fifth embodiment on which a bonding force increasing portion 30E is formed.
20, the same components as those shown in FIGS. 17 to 19 are denoted by the same reference numerals, and description thereof will be omitted. The joining force increasing portion 30D according to the fourth embodiment shown in FIG.
In this embodiment, four slit-shaped through portions 31D are provided, and these are arranged in a cross shape. On the other hand, in the joining force increasing portion 30D according to the present embodiment, the center position (the center position of the die pad 23F) of each of the four penetrating portions 31E arranged in a cross shape.
The end portions close to are connected to each other.

As described above, by communicating the central positions of the four penetrating portions 31E, the stress relaxing function of the four penetrating portions 31E as a whole can be further increased, and the die attaching material 24 and the die pad 23E are formed. The separation at the interface with the substrate can be more reliably prevented. Note that the configurations of the penetrating portion and the step portion that constitute the joining force increasing portion are not limited to the above-described configurations, and the resin package is disposed so as to surround the step portion, whereby the joining strength between the resin package and the die pad is increased. Any other configuration may be used as long as the configuration improves.

[0062]

According to the present invention as described above, the following various effects can be realized. According to the first, second, fourth, and seventh aspects of the invention, the bonding strength between the resin package and the die pad can be improved, so that even when heat is applied during mounting or the like. In addition, peeling at the interface between the resin package and the die pad and swelling occurring on the back surface of the resin package can be prevented, and the reliability of the semiconductor device can be improved.

Further, since the step portion is formed within the thickness range of the die pad, the die pad does not become thick even if the step portion is provided. Therefore, high reliability can be realized while keeping the semiconductor device thin. Also,
According to the third aspect of the present invention, even if heat is applied to the semiconductor device and a stress is generated in each of the joining force increasing portions, the stress applied to each of the joining force increasing portions is substantially uniform, so that the stress is applied unevenly. Therefore, separation of the die pad from the resin package and swelling of the resin package can be more effectively prevented.

According to the fifth aspect of the present invention, the bonding force increasing portion can be formed simultaneously with the formation of the lead and the die pad, and the lead frame can be formed easily and efficiently. According to the sixth aspect of the present invention, since the deformation (extension) of the stepped portion generated when the stepped portion is crushed is released to the penetrating portion, distortion and warpage of the die pad can be prevented, and the die pad can be prevented. Can be maintained flat.

According to the seventh aspect of the present invention, since the penetrating portion is formed in a slit shape, even though the step portion is provided inside, the portion through which the resin can pass is wide, so that the resin package is formed. The flow resistance of the sometimes filled resin is reduced, so that the filling of the resin can be facilitated.
In addition, since the through-hole formed in the die pad has a slit shape, the through-hole can have a stress relaxation function. Therefore, the stress generated in the die pad due to a difference in thermal expansion between the die pad and the die-attaching material can be increased. Can be reduced by the penetrating portion. Thus, in the same manner as in each of the above-described claims, separation prevention at the interface between the resin package and the die pad and swelling on the back surface of the resin package can be prevented, and further, separation prevention at the interface between the die attach material and the die pad can be realized. As a result, the reliability of the semiconductor device can be further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a conventional semiconductor device (part 1).

FIG. 2 is a plan view of a lead frame used to manufacture the semiconductor device shown in FIG.

FIG. 3 is an enlarged sectional view of a main part for explaining a semiconductor device as an example of the related art (part 2).

4 is a plan view of a lead frame used for manufacturing the semiconductor device shown in FIG.

FIG. 5 is an enlarged sectional view of a main part for describing a semiconductor device as an example of the related art (part 3).

6 is a plan view of a lead frame used to manufacture the semiconductor device shown in FIG.

FIG. 7 is a cross-sectional view of the semiconductor device according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a modification of the semiconductor device according to the first embodiment;

FIG. 9 is a view for explaining a lead frame forming step in the method of manufacturing a semiconductor device according to one embodiment of the present invention;

FIG. 10 is an enlarged view of a first embodiment of a bonding force increasing portion formed in a lead frame forming step.

FIG. 11 is a view for explaining a package forming step in the method of manufacturing a semiconductor device according to one embodiment of the present invention (part 1);

FIG. 12 is a view for explaining a package forming step in the method for manufacturing a semiconductor device according to one embodiment of the present invention (part 2);

FIG. 13 is a view for explaining a package forming step in the method of manufacturing a semiconductor device according to one embodiment of the present invention (part 3);

FIG. 14 is an enlarged view showing a second embodiment of a bonding force increasing portion formed in a lead frame forming step.

FIG. 15 is a sectional view of a semiconductor device according to a second embodiment of the present invention.

FIG. 16 is an enlarged view showing a third embodiment of a bonding force increasing portion formed in a lead frame forming step.

FIG. 17 is an enlarged view of a fourth embodiment of the joining force increasing portion.

FIG. 18 is a sectional view taken along the line AA in FIG.

19 is an enlarged perspective view showing a joining force increasing portion in FIG. 17;

FIG. 20 is an enlarged view of a fifth embodiment of the joining force increasing portion.

[Explanation of symbols]

 Reference Signs List 20A to 20C Semiconductor device 22 Semiconductor chip 23A to 23F Die pad 24 Die attaching material 27 Resin package 30A to 30E Bonding force increasing part 31A to 31E Penetrating part 32A to 32D Step part 33 Interposed resin part 34 Adhesive 35 Base material 36 Lead frame 40 gap 41 resin

Claims (7)

[Claims] 1. A semiconductor device comprising: a semiconductor chip; a die pad on which the semiconductor chip is mounted via a die attaching material; and a resin package for sealing the semiconductor chip and the die pad. A bonding portion formed by a penetrating portion penetrating the die pad and a step portion formed within a thickness range of the die pad and formed to have a gap between the semiconductor chip; A semiconductor device wherein a part of a package is interposed in a gap between the semiconductor chip and the step. 2. The semiconductor device according to claim 1, wherein a part of the resin package is formed so as to surround the step. 3. The semiconductor device according to claim 1, wherein a plurality of said joining force increasing portions are formed, and an arrangement position thereof is set at a position symmetrical with respect to a center of said die pad. Semiconductor device. 4. A lead frame forming step of forming a lead frame having at least a lead and a die pad from a base material, and after mounting a semiconductor chip on the lead frame, sealing at least the semiconductor chip and the die pad. In a method for manufacturing a semiconductor device having a package forming step of arranging a resin and forming a resin package, in the lead frame forming step, a penetrating portion penetrating the die pad and formed within a thickness range of the die pad are formed. And a bonding force increasing portion comprising a step portion having a thickness smaller than the thickness of the die pad is collectively formed on the die pad, and in the package forming step, the resin is formed between the semiconductor chip and the step portion. Characterized in that it is configured to be introduced also into a gap formed between the semiconductor and the semiconductor device. Manufacturing method of body device. 5. The semiconductor device manufacturing method according to claim 4, wherein in the lead frame forming step, the lead, the die pad, and the bonding force increasing portion are formed using a press working method. Device manufacturing method. 6. The method for manufacturing a semiconductor device according to claim 5, wherein, when the bonding force increasing portion is formed in the lead frame forming step, the through portion is first punched out, and thereafter, corresponds to the step portion. A method of manufacturing a semiconductor device, wherein the step is formed by crushing a position. 7. A semiconductor device comprising: a semiconductor chip; a die pad on which the semiconductor chip is mounted via a die attaching material; and a resin package for sealing the semiconductor chip and the die pad. A slit-shaped penetrating portion penetrating the die pad, and a plurality of step portions formed in the penetrating portion with a thickness within the thickness range of the die pad and configured to have a gap between the semiconductor chip. A semiconductor device, comprising: a bonding force increasing portion configured so that a part of the resin package is interposed also in a gap between the semiconductor chip and the step portion.