JP2003110080A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small semiconductor device in which high density mounting can be realized while enhancing heat dissipation effect by forming a plurality of heat dissipation planes on the surface of a semiconductor chip. SOLUTION: The semiconductor device 21 comprises a semiconductor element 22, a lead frame 31 having a plurality of lead parts 23 extending toward the semiconductor element 22, and a resin material 24 for sealing the semiconductor element 22 and the lead parts 23. Each lead part 23 is formed integrally with a column part 26 and a supporting part 28 projecting from the side face of the column part 26 toward the semiconductor element 22 disposed on the upper surface at the forward end of the supporting part 28. When the semiconductor element 22 and the lead parts 23 are sealed with the resin material 24, the upper surface 23a, side face 23b and bottom face 23c of each column part 26 are exposed as the heat dissipation planes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type semiconductor device using a lead frame.

[0002]

2. Description of the Related Art Conventionally, a chip type semiconductor device having a plurality of electrode portions (hereinafter referred to as a semiconductor chip) has a semiconductor element mounted on a metal lead frame having a lead portion and an island portion. It is formed by sealing the top with a resin material. The island portion is for supporting the semiconductor element, and is provided in the central portion of the lead frame. The lead portion is connected to the element electrode portion of the supported semiconductor element via a bonding wire or the like, and one end thereof is an external electrode portion connected to an external substrate. FIG. 5 shows an internal structure of such a conventional semiconductor chip 1, and FIG. 6 shows a lead frame 2 for forming the semiconductor chip 1.
The lead frame 2 is a 42 alloy (Ni 42% Ni-
A thin metal strip such as a Fe alloy), aluminum, or copper is used to provide a plurality of chip forming regions A in which the island portions 4 and the lead portions 7 are punched and formed. The island part 4 is installed at a position lower by one step by recessing four arm parts 10 extending inward from the lead frame body 6. Further, the lead portion 7 is formed with an electrode portion 5 serving as an external electrode of the semiconductor chip 1 at the tip, and is bent downward toward the end portion of the island portion 4. Therefore, when the semiconductor material 1 is formed by filling the resin material 9 in the chip forming region A, the electrode portions 5 become lower surface electrodes connected to the external substrate 14 such as a mother board. On the other hand, the end portion of each arm portion 10 extending from the island portion 4 serves as a heat dissipation member with which the side surface of the resin material 9 is exposed.

One semiconductor chip 1 as shown in FIG.
First, the semiconductor element 3 is formed on the island portion 4 in order to form the
Then, the element electrode portion 11 of the semiconductor element 3 and the electrode portion 5 at the tip of the lead portion 7 are connected by the bonding wire 8. Then, the lead 7 and the arm 10 are filled with the resin material 9 centering around the semiconductor element 3 and sealed, and then the lead 7 and the arm 10 outside the resin material 9 are separated from the lead frame body 6 to form a single body. The semiconductor chip 1 is taken out. The semiconductor chip 1 thus formed is mounted by soldering the electrode portions 5 exposed on the lower surface of the resin material 9 to the electrode terminals 16 of the external substrate 14 such as a mother board.

The conventional semiconductor chips 12 and 15 shown in FIGS. 7 and 8 are provided with a heat dissipation member,
This is an example in which the heat dissipation effect is further enhanced. Semiconductor chip 1
2, the fins 13 for heat dissipation are separately provided on the back surface side of the island portion 4 on which the semiconductor element 3 is mounted.
The heat generated from the fins is radiated through the fins 13 (see Japanese Patent Laid-Open No. 3-214763). On the other hand, in the semiconductor chip 15, the tip of the arm portion 10 that supports the island portion 4 is projected from the resin material 9. In this way, the arm 1
By exposing one end of 0 from the resin material 9, the heat generated from the semiconductor element 3 is radiated from the tip of the arm 10 (see Japanese Patent Laid-Open No. 1-128887).

[0005]

However, in the semiconductor chip 12 shown in FIG. 7, since the fins 13 for heat radiation must be provided separately, the number of manufacturing steps and the number of manufacturing steps increase as the number of parts increases. There was a problem that the cost increased.

On the other hand, in the semiconductor chip 15 shown in FIG. 8, since the tip of the arm portion 10 protruding from the side surface of the resin material 9 functions as a heat sink, the heat sink is separately provided as described above. Although it is not necessary to provide the above, when mounting on the external substrate 14 such as a mother board as shown in FIG. 5, the mounting area of the semiconductor chip 15 becomes wider by the amount that the arm portion 10 projects laterally. Therefore, there are restrictions on high-density mounting and miniaturization.

Therefore, a first object of the present invention is to provide a semiconductor device capable of efficiently radiating heat generated from a semiconductor element without increasing the number of parts, the number of manufacturing steps and the cost.

A second object of the present invention is to provide a small-sized semiconductor device capable of high-density mounting while enhancing the heat dissipation effect by forming a plurality of heat dissipation surfaces on the surface of a semiconductor chip. is there.

[0009]

In order to solve the above-mentioned problems, a semiconductor device according to claim 1 of the present invention includes a semiconductor element and a lead frame having a plurality of lead portions extending toward the semiconductor element. In a semiconductor device including the semiconductor element and a resin material for sealing the lead section, each of the lead sections is integrally formed of a pillar section and a support section protruding from a side surface of the pillar section toward the semiconductor element. The semiconductor element is installed on the upper surface of the tip of the supporting portion, and the outer peripheral surface of each column portion is exposed when the semiconductor element and the lead portion are sealed with a resin material.

According to the present invention, since each lead portion has the support portion on which the semiconductor element is mounted and the column portion whose outer peripheral surface is exposed, the heat generated in the semiconductor element is generated from the support portion by the column portion. To the outside of the column, and is further discharged from the outer peripheral surface of the column. In addition, by exposing the top surface, the side surface, and the bottom surface of the pillar portion, it is possible to more effectively release the heat generated from the semiconductor element.

According to a third aspect of the present invention, in the semiconductor device according to the first aspect, the supporting portion is projected from a side surface below the center of the column portion in the height direction, and a semiconductor element is installed at the tip of the supporting portion. The top surface of the pillar portion is located above the semiconductor element when the above is performed.

According to the present invention, since the supporting portion on which the semiconductor element is mounted projects from the lower side of the center of the pillar portion,
When the resin material is filled up to the vicinity of the upper surface of the pillar portion, the semiconductor element, the bonding wire and the like can be completely embedded and sealed.

According to a fourth aspect of the present invention, in the semiconductor device according to the first aspect, the lead portion is formed of a thick metal strip plate constituting a lead frame, and has the same height as the thickness of the metal strip plate. It is characterized in that it is composed of a pillar portion having and a supporting portion formed by recessing a metal strip plate.

According to the present invention, since the thickness of the thick metal strip plate is directly set to the height of the column portion, the area exposed to the outside can be effectively increased. Further, the supporting portion can be easily formed by recessing the metal strip plate by etching or the like, and the lead portion is formed integrally with the pillar portion.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a semiconductor chip according to the present invention will be described in detail below with reference to the accompanying drawings. Figure 1
2 is a perspective view of a semiconductor chip showing a first embodiment of the present invention, and FIG. 2 is a sectional view of the semiconductor chip mounted on an external substrate such as a mother board.

As shown in FIGS. 1 and 2, the semiconductor chip 21 according to this embodiment includes a semiconductor element 22, four lead portions 23 on which the semiconductor element 22 is mounted, and the lead portion 23. It is composed of a resin material 24 that seals the semiconductor element 22. The semiconductor element 22 is a square silicon crystal thin plate, and has element electrode portions 25 at four corners. Each lead portion 23 is formed with a thickness in the height and width directions, and has a block-shaped column portion 26 extending vertically and a flat plate-shaped support portion 28 protruding horizontally from one side surface of the column portion 26. And form a substantially L-shaped cross section.
The lead portions 23 thus formed are arranged in two rows with the tips of the support portions 28 facing each other, as shown in FIG. Then, the four corners of the semiconductor element 22 are placed on the upper surface of each support portion 28, and the element electrode portions 25 are electrically connected to the support portions 28 via the solder bumps 29. After that, the semiconductor element 22 and the entire lead portion 23 are sealed with the resin material 24 to form one semiconductor chip 21. The semiconductor chip 21 thus formed is made of the resin material 2
The upper surface 23a, the side surface 23b, and the bottom surface 23c of the pillar portion 26 are exposed on the surface of No. 4. Since the exposed upper surface 23a, side surface 23b, and bottom surface 23c serve as a heat dissipation surface in contact with the outside air, the heat generated in the semiconductor element 22 can be efficiently released to the outside of the semiconductor chip 21. Further, the bottom surface 23c of the pillar portion 26 serves as an electrode surface installed on the electrode pattern 30b of the external substrate 30a such as a mother board. The bottom surface 23c may be recessed to slightly float the lower surface of the supporting portion 28, as shown in FIG. 1, in order to match the connection surface with the electrode pattern 30b of the external substrate 30a.

FIG. 3 shows a lead frame 31 which is a base for forming the semiconductor chip 21. The lead frame 31 is made of a material such as 42 alloy (Ni 42% Ni—Fe alloy), aluminum, copper, etc. as in the conventional case, but in the present embodiment, the lead frame 31 is made of a thick metal strip. The thickness is the same as the height of the semiconductor chip 21. A large number of chip forming regions B for forming the semiconductor chips 21 are arranged on the long lead frame 31, and four lead portions 23 are formed in each chip forming region B so as to face each other. Each lead portion 23 is a block-shaped column portion 2 having the same height as the thickness of the lead frame 31.
6 and a flat plate-shaped support portion 28 formed by recessing the inside of the column portion 26.

Next, a description will be given of a case where the lead frame 31 having the above-mentioned structure is manufactured by two steps of punching and etching, but the lead frame 31 can be formed only by etching. The following (1) to (2) show the manufacturing steps of the lead frame 31 and the semiconductor chip 21 using the lead frame 31 in order. This manufacturing process will be described with reference to FIGS. First, a thick metal strip is punched by a pressing process, an etching process, or the like, leaving a portion to be formed in the lead portion 23, to form a chip forming region B. Next, the tip portion of each lead portion 23 toward the central portion in the chip forming region B is deeply recessed by etching from above. As a result, the lead portion 23 is formed in an L-shaped cross section by the pillar portion 26 and the support portion 28 that horizontally projects from the inner side surface of the pillar portion 26. Further, the lower surface of the lead portion 23 is also provided with a recessed portion by etching if necessary. However, it is the pillar portion 26 that the lower surface side is recessed.
This is because the support portion 28 is slightly floated from the bottom surface 23c of the base plate 23c, so that it is not necessary to make a deep recess. The solder bump 2 is formed on the tip of the formed support portion 28.
The element electrode portion 25 of the semiconductor element 22 on which 9 is formed is placed and subjected to a reflow process to be welded to the tip portion of the support portion 28. Next, the resin material 24 is filled in the chip forming region B in which the semiconductor element 22 is mounted. At this time, the amount of filling is adjusted so that the upper surface 23a and the bottom surface 23c of each lead portion 23 are exposed, and resin sealing is performed. Chip forming area B sealed by the resin material 24
The lead frame 31 is cut along the outer frame of the semiconductor chip to divide it into individual semiconductor chips 21. Through the above steps, the semiconductor chip 21 as shown in FIG. 1 can be manufactured.

FIG. 4 shows a second embodiment of the semiconductor chip of the present invention. Semiconductor chip 41 of the present embodiment
The semiconductor chip 42 is mounted on the semiconductor chip 21.
The flip chip mounting method is replaced with the wire bond mounting method. Therefore, the element electrode portion 45 of the semiconductor element 42 is placed in an upward state, the opposite surface is fixed to the end portion of the support portion 28 with an adhesive, and then the element electrode portion 45 of the semiconductor element 42 is supported by the bonding wire 43. The one end of the portion 28 is electrically connected.

As shown in the first and second embodiments, in the semiconductor chips 21 and 41 of the present invention, the lead portions 23 which are the bases of the semiconductor elements 22 and 42 make use of the thickness of the lead frame 31. Since the upper surface 23a, the side surface 23b, and the bottom surface 23c of the lead portion 23 are three-dimensionally exposed, the heat generated by the semiconductor elements 22 and 24 can be efficiently radiated to the outside of the semiconductor chips 21 and 41. it can. Further, the heat radiation direction is also the upper surface 23 of each lead portion 23.
Since a, the side surface 23b, and the bottom surface 23c are even, it is possible to uniformly cool the entire semiconductor chips 21 and 41. Depending on the size of the lead portion 23, the upper surface 23
A predetermined heat dissipation effect can be obtained without exposing all of a, the side surface 23b, and the bottom surface 23c.

The surface for radiating heat is the semiconductor chip 21,
Since it has a structure in which it is formed flat along the outer surface without protruding from 41, the overall shape and size of the semiconductor chips 21 and 41 are different from those in the case where a conventional heat sink is separately formed or lead portions are extended. It is smaller than the semiconductor chip used as a heat sink. For this reason, it is possible to perform high-density mounting on an external substrate such as a mother board with a narrow space.

The semiconductor chip 21 of the above embodiment,
41, the element electrode portions 25, 4 of the semiconductor elements 22, 42
Although the example of the case where 5 is 4 poles is shown, it is not limited to such a semiconductor chip structure, but by changing the lead part structure of the lead frame, a small number of poles such as 2 poles or a multi pole of 4 poles or more can be obtained. It can also be applied to semiconductor devices.

[0023]

As described above, according to the semiconductor device of the present invention, each lead portion includes the support portion on which the semiconductor element is mounted and the column portion whose outer peripheral surface is exposed.
The heat generated in the semiconductor element can be transferred from the supporting portion to the pillar portion, and can be further radiated to the outside from the outer peripheral surface of the pillar portion. Further, when the top surface, side surface and bottom surface of the pillar portion are exposed, the heat received from the semiconductor element can be efficiently radiated to the outside of the semiconductor device.

Further, according to the present invention, since the thickness of the thick lead frame is the height of the column portion as it is, the area exposed to the outside can be effectively increased.
Further, there is an effect that the supporting portion can be easily formed by recessing the metal strip plate by etching or the like.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of a semiconductor device according to the present invention.

FIG. 2 is a sectional view of the semiconductor device of FIG.

FIG. 3 is a perspective view of a lead frame of the semiconductor device of FIG.

FIG. 4 is a perspective view of a second embodiment of a semiconductor device according to the present invention.

FIG. 5 is a cross-sectional view of a semiconductor device manufactured using a conventional lead frame.

FIG. 6 is a perspective view of the lead frame used in FIG. 5;

FIG. 7 is a perspective view showing an example of a conventional semiconductor device provided with heat dissipation measures.

FIG. 8 is a perspective view showing another example of a conventional semiconductor device provided with heat dissipation measures.

[Explanation of symbols]

21,41 Semiconductor device (semiconductor chip) 22,42 Semiconductor element 23 Lead 23a upper surface 23b side 23c bottom 24 Resin material 25,45 Element electrode part 26 Pillars 28 Support 31 lead frame

Claims (4)

[Claims] 1. A semiconductor device comprising a semiconductor element, a lead frame having a plurality of lead portions extending toward the semiconductor element, and a resin material for sealing the semiconductor element and the lead portion, wherein each of the lead portions is provided. Is formed integrally with a pillar portion and a supporting portion protruding from the side surface of the pillar portion toward the semiconductor element, and the semiconductor element is installed on the top surface of the tip of the supporting portion, and the semiconductor element and the lead portion are made of resin. A semiconductor device, wherein an outer peripheral surface of each pillar portion is exposed when sealed with a material. 2. The semiconductor device according to claim 1, wherein the outer peripheral surface of the pillar portion is an upper surface, a side surface and a bottom surface of the pillar portion. 3. The support portion is projected from a side surface below the center of the column portion in the height direction, and the upper surface of the column portion is located above the semiconductor element when the semiconductor element is installed at the tip of the support portion. The semiconductor device according to claim 1, wherein 4. The lead portion is formed of a thick-walled metal strip plate which constitutes a lead frame, and a column portion having the same height as the thickness of the metal strip plate is formed by recessing the metal strip plate. 2. The semiconductor device according to claim 1, wherein the semiconductor device is formed of: