JPH05160309A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the heat radiation property of the power element of a semiconductor device. CONSTITUTION:To eliminate voids in the solder between a power element and a primary heat sink 7 and between a primary heat sink 10 and an insulating board 9, the heat sink 10 is provided with an inclination or a groove, and soldering is performed by heating it in inert atmosphere or reductive atmosphere. Accordingly, since no void is present, each part contacts with each other only by the solder, so the heat conductivity from the power element 1 to the heat sink 7 improves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a semiconductor device having a power element heat generating portion.

[0002]

2. Description of the Related Art FIGS. 5A to 5I are assembly diagrams of a conventional semiconductor device manufacturing method. In FIG. 5a, an electrode 2 for forming a circuit is fired on a ceramic substrate 1 which is a substrate for forming a control circuit for controlling a power element. Further, mounting electrodes called lands for mounting components are arranged. Next, FIG. 5b shows that the above-mentioned mounting electrode 2 is made into a paste form by mixing solder powder called solder paste 3, flux, solvent and the like, and applied to necessary places by a printing method or the like. FIG. 5c shows that the integrated circuit element 4, the passive component 6, the connection pad 5 used for connection with the power element, and the like, which constitute the circuit, are placed at predetermined positions and heated to remelt the solder in the solder paste 3, This is soldering, and this is called the solder reflow method. After that, the lead wire 12 used to connect to the outside
To solder. FIG. 5d shows a step of mounting the power element and the control circuit on the heat sink. The insulating substrate 9, the primary heat sink 10, and the power element 11 are stacked at predetermined positions of the heat sink 7 with the solder plate 8 interposed therebetween.
The figure shows a state in which the solder is remelted by heating in an inert atmosphere or a reducing atmosphere to perform soldering, and thereafter the substrate 1 of the control circuit is bonded to a predetermined position of the heat sink with an adhesive. .. FIG. 5e shows a state where the control circuit board is connected to the power element by wire bonding after being bonded. The control circuit board is bonded to the predetermined position of the heat sink 7 with the adhesive 13, and then the power element 11 and the control circuit board are bonded. The upper connection pad 5 is connected by bonding an aluminum wire 14 by an ultrasonic wire bonding method. FIG. 5f shows a resin molded package 15 with an adhesive 13 in order to protect the above components mechanically and environmentally.
Then, the lead wire 12 is connected to the external terminal 15a integrally formed with the package 15 by soldering or welding. In FIG. 5g, the lid 16 is adhered to the one shown in FIG. Next, FIG. 6a is a diagram showing that the solder is remelted by heating in an inert atmosphere or a reducing atmosphere. Since the solder is heated in the above atmosphere, the product is in contact with the above atmosphere. Since the heat is further transferred to the inside, it is temporarily divided into the molten solder portion 19 and the unmelted portion 20. Further, although the solder 8 is plate-shaped, it is not always flat, and therefore it may contain air. FIG. 6B shows the place where all the solder has melted. Since the solder begins to melt from the outside, voids 1 remain in the solder 19 where the gas generated inside melts.
It will be 8.

[0003]

In the conventional primary heat sink, since the heat sink and the power element mounting surface are designed to be parallel to each other and to be horizontal with the insulating substrate, voids are generated in the solder after fusion. Even if it occurs, it will not come out. Therefore, there is a problem in that the voids deteriorate the thermal conductivity, the heat dissipation effect expected at the time of design cannot be obtained, and the reliability is deteriorated.

The present invention has been made to solve the above problems, and an object thereof is to eliminate variations in heat conduction from a power element to a heat sink as designed.

[0005]

In a primary heat sink of a semiconductor device according to the present invention, an inclination is provided so that the secondary heat sink and the component mounting surface are not parallel, and the surface facing the insulating substrate is also parallel to the insulating substrate. It does not. Further, grooves are provided on both upper and lower surfaces of the primary heat sink.

[0006]

In the primary heat sink according to the present invention, since the void is removed from the upper surface of the slope by forming the slope on the solder-bonding surface, the insulating substrate and the primary heat sink, and the primary heat sink and the power element are contacted only by the solder, so that the heat radiation performance is improved. Is improved. Further, by providing the groove, the voids escape to the outside of the groove, which improves the heat dissipation.

[0007]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 10 is a primary heat sink having an inclination, and 7, 8, 9, and 11 are the same as those in the prior art. That is, in the prior art, the primary heat sink 10 is parallel to the heat sink 7, but the component mounting surface 10a and the insulating substrate surface 10b are inclined so that they are not horizontal as shown in FIG. When the solder 8 is used for fusion, the voids in the solder 8 escape to the outside from the upper surface of the slope due to the inclination, so that the fusion can be performed only by the solder.

Example 2. FIG. 2 shows another embodiment of the present invention, in which the primary heat sink 10 is provided with an air vent hole 16 on the side of the insulating substrate 9 that is inclined toward the inner side and that is inwardly upward from the center portion. Is.

Embodiment 3. Although the slopes are provided on both sides in the first embodiment, as shown in FIG.
The power element surface 10a may be inclined.

Embodiment 4. It should be noted that although in the above-described embodiment, the one having the inclination is shown, as shown in FIG. 4, by providing the grooves 17 on the upper and lower sides of the primary heat sink 10, the void 18 generated in the solder is desired to form the groove. When it is made to escape to the outside, the heat generated by the power element 11 is efficiently transmitted to the solder 8, the primary heat sink 10, the solder 8, the insulating substrate 9, the solder 8, and the heat sink 7 as long as there are no voids in the solder. Therefore, the heat dissipation effect is improved.

[0011]

As described above, according to the present invention, since voids (air) do not enter the solder, connection can be made only by solder, which improves the thermal conductivity from the power element to the heat sink. Since there is no occurrence of poor conductivity, manufacturing can be performed with high yield, and product cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

5A to 5G are assembly diagrams of a conventional manufacturing method.

FIG. 6 is a diagram showing a molten state of solder in a conventional manufacturing method.

[Explanation of symbols]

 1 Ceramic Substrate 2 Electrode 3 Solder Paste 4 Integrated Circuit Element 5 Connection Pad 6 Passive Component 7 Heat Sink 8 Solder Plate 9 Insulating Substrate 10 Primary Heat Sink 11 Power Element 16 Air Vent Hole 17 Groove

[Procedure amendment]

[Submission date] December 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Semiconductor device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a semiconductor device having a power element heat generating portion.

[0002]

5 to 11 are assembly diagrams of a conventional method of manufacturing a semiconductor device. In FIG. 5, an electrode 2 for forming a circuit is fired on a ceramic substrate 1 which is a substrate for forming a control circuit for controlling a power element. Further, mounting electrodes called lands for mounting components are arranged. Next, FIG. 6 shows the above-mentioned mounting electrode 2 in which a solder powder called a solder paste 3, a flux, a solvent and the like are mixed to form a paste, which is applied to necessary places by a printing method or the like. In FIG. 7 , the integrated circuit element 4, the passive component 6, and the connection pad 5 used for connection with the power element, which form the circuit, are placed at predetermined positions and heated to remelt the solder in the solder paste 3, This is soldering, and this is called the solder reflow method. After that, the lead wire 12 used for connection to the outside is soldered. FIG. 8 shows a process of mounting the power element and the control circuit on the heat sink . The insulating substrate 9, the primary heat sink 10, and the insulating substrate 9 are provided at predetermined positions of the heat sink 7.
It shows a state in which the power elements 11 are stacked with the solder plate 8 sandwiched therebetween, and heated in an inert atmosphere or a reducing atmosphere to remelt the solder for soldering, and thereafter, at a predetermined position on the heat sink. The substrate 1 of the control circuit is bonded with an adhesive. FIG. 9 shows a state in which the control circuit board is connected to the power element by wire bonding after being bonded . The control circuit board is bonded to the predetermined position of the heat sink 7 with the adhesive 13, and then the power element 11 and the control circuit board are bonded. The upper connection pad 5 is connected by bonding an aluminum wire 14 by an ultrasonic wire bonding method. In FIG. 10, in order to protect the above components mechanically and environmentally, a resin-molded package 15 is adhered with an adhesive agent 13, and then a lead wire 12 is attached to an external terminal 15a integrally molded with the package 15. They are connected by soldering or welding. In FIG. 11 , the lid 16 is bonded to the one in FIG. Next, FIG. 12 is a diagram showing that the solder is remelted by heating in an inert atmosphere or a reducing atmosphere. However, since the solder is heated in the above atmosphere, the product is in contact with the above atmosphere. Since the heat is further transferred to the inside, the molten solder portion 19 and the unmelted portion 20 are temporarily separated. Further, the solder 8 is plate-shaped, but is not necessarily flat, and therefore it may contain air. FIG. 13 shows a portion where all the solder has melted . Since the solder begins to melt from the outside, voids 18 remain in the solder 19 where the gas generated inside melts.
become.

[0003]

In the conventional primary heat sink, since the heat sink and the power element mounting surface are designed to be parallel to each other and to be horizontal with the insulating substrate, voids are generated in the solder after fusion. Even if it occurs, it will not come out. Therefore, there is a problem in that the voids deteriorate the thermal conductivity, the heat dissipation effect expected at the time of design cannot be obtained, and the reliability is deteriorated.

The present invention has been made to solve the above problems, and an object thereof is to eliminate variations in heat conduction from a power element to a heat sink as designed.

[0005]

In a primary heat sink of a semiconductor device according to the present invention, an inclination is provided so that the secondary heat sink and the component mounting surface are not parallel, and the surface facing the insulating substrate is also parallel to the insulating substrate. It does not. Further, grooves are provided on both upper and lower surfaces of the primary heat sink.

[0006]

In the primary heat sink according to the present invention, since the void is removed from the upper surface of the slope by forming the slope on the solder-bonding surface, the insulating substrate and the primary heat sink, and the primary heat sink and the power element are contacted only by the solder, so that the heat radiation performance is improved. Is improved. Further, by providing the groove, the voids escape to the outside of the groove, which improves the heat dissipation.

[0007]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 10 is a primary heat sink having an inclination, and 7, 8, 9, and 11 are the same as those in the prior art. That is, in the prior art, the primary heat sink 10 is parallel to the heat sink 7, but the component mounting surface 10a and the insulating substrate surface 10b are inclined so that they are not horizontal as shown in FIG. When the solder 8 is used for fusion, the voids in the solder 8 escape to the outside from the upper surface of the slope due to the inclination, so that the fusion can be performed only by the solder.

Example 2. FIG. 2 shows another embodiment of the present invention in which the insulating substrate 9 side of the primary heat sink 10 is inclined toward the inner side, and the air vent hole 16 is provided inward from the central portion toward the upper side. Is.

Embodiment 3. Although the slopes are provided on both sides in the first embodiment, as shown in FIG.
The power element surface 10a may be inclined.

Embodiment 4. It should be noted that although in the above-described embodiment, the one having the inclination is shown, as shown in FIG. 4, by providing the grooves 17 on the upper and lower sides of the primary heat sink 10, the void 18 generated in the solder is desired to form the groove. When it is made to escape to the outside, the heat generated by the power element 11 is efficiently transmitted to the solder 8, the primary heat sink 10, the solder 8, the insulating substrate 9, the solder 8, and the heat sink 7 as long as there are no voids in the solder. Therefore, the heat dissipation effect is improved.

[0011]

As described above, according to the present invention, since voids (air) do not enter the solder, connection can be made only by solder, which improves the thermal conductivity from the power element to the heat sink. Since there is no occurrence of poor conductivity, manufacturing can be performed with high yield, and product cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

FIG. 5 is an assembly diagram of a conventional manufacturing method.

FIG. 6 is an assembly diagram of a conventional manufacturing method.

FIG. 7 is an assembly diagram of a conventional manufacturing method.

FIG. 8 is an assembly diagram of a conventional manufacturing method.

FIG. 9 is an assembly diagram of a conventional manufacturing method.

FIG. 10 is an assembly diagram of a conventional manufacturing method.

FIG. 11 is an assembly diagram of a conventional manufacturing method.

FIG. 12 shows a molten state of solder in a conventional manufacturing method.
FIG.

FIG. 13 shows a molten state of solder in a conventional manufacturing method.
FIG.

[Explanation of symbols] 1 ceramic substrate 2 electrode 3 solder paste 4 integrated circuit element 5 connection pad 6 passive component 7 heat sink 8 solder plate 9 insulating substrate 10 primary heat sink 11 power element 16 air vent hole 17 groove

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

FIG. 11

[Fig. 12]

[Fig. 13]

Claims (4)

[Claims] 1. A semiconductor device having a three-layer structure in which an insulating substrate, a primary heat sink, and a power element are fused together by solder on a heat dissipation plate, wherein an inclination is provided on the power element side of the primary heat sink. Semiconductor device. 2. A semiconductor device having a three-layer structure in which an insulating substrate, a primary heat sink, and a power element are fused on a heat sink by soldering, respectively, and a tilt is provided on both sides of the power element side and the insulating substrate side of the primary heat sink. A semiconductor device provided. 3. A semiconductor device having a three-layer structure in which an insulating substrate, a primary heat sink, and a power element are fused on a heat dissipation plate with solder, respectively, in which the insulating substrate side of the primary heat sink faces upward from both sides inward. With a slope,
Further, a semiconductor device is characterized in that an oblique air vent hole is provided inward and upward from a central portion thereof. 4. A semiconductor device having a three-layer structure in which an insulating substrate, a primary heat sink and a power element are fused on a heat sink by soldering, respectively, and grooves are provided on both upper and lower sides of the primary heat sink. Semiconductor device.