JPH1140724A - Semiconductor device, its manufacturing method and its manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which comprises a heat sink having a high radiating effect and suitable for miniaturization of a package and radiating fin leads, and also to provide a method for manufacturing the semiconductor device and an apparatus for manufacturing the semiconductor device. SOLUTION: A heat sink 1 is formed in its side with a stepped part, and a radiating fin lead 3 of a metallic plate having a through hole made in its major surface is pressed against the heat sink along the configuration of the stepped part to surround it. In this case, the outer edges will cover the radiating fin lead 3. A metallic tool is pushed so as to make a groove 9 having first and second side faces 10 and 11 in each outer edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a heat sink and a radiating fin, a method of manufacturing the same, and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, proposals have been made on a structure of a small package in which a semiconductor integrated circuit having relatively large power consumption is built and a method of manufacturing the same in order to cope with miniaturization of equipment. For example, this specific technique is disclosed in
No. 86558.

FIGS. 10A and 10B are views showing a conventional semiconductor device. The semiconductor pellet 100 is bonded to a tab 102 via a bonding layer 101. The radiating fin lead 103 is continuous with the tab 102, and the radiating fin 105 is further connected to the resin package 104.
It is continuous outside. On the other hand, the heat sink 106 is in contact with the tab 102 inside the resin package 104,
A rivet 107 is provided at an end of the heat sink 106, and a coupling hole 108 is provided in the radiation fin lead 103 corresponding to the rivet 107. Here, the tip of the rivet 107 is fixed to the coupling hole 108 by swaging. By providing such a structure, heat generated in the semiconductor pellet 100 can be transferred to the radiation fins 1.
05 and the heat sink 106.

[0004]

However, such a conventional semiconductor device requires a plurality of pairs of rivet portions and coupling holes, and the distance between the rivet portions is equal to the distance between the coupling holes. Therefore, high processing accuracy was required.

Further, in order to secure the strength of the caulking process, it is necessary to increase the diameter of the rivet portion. In such a case, the area of the lead for wiring is relatively narrowed. A relatively large area was required for the shape of the package to secure the area.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a semiconductor device having a high heat radiation effect and suitable for downsizing of a package, a method of manufacturing the same, and a manufacturing apparatus thereof.

[0007]

According to a first aspect of the present invention, there is provided a heat sink having a step-like step formed on a side surface of a heat sink and including the step along the shape of the step. A radiation fin lead having a through hole formed in the main surface of the metal plate is provided, and the through hole is pressure-bonded to a step on the side surface of the heat sink. Here, a mechanical pressure is applied along the outer edge of the main surface of the heat sink, and the outer edge is crimped so as to cover the heat radiation fin lead. In this case, a groove shape is formed by the mechanical pressure. still,
This groove is formed along the outer edge of the heat sink,
It can also be formed at four corners in the form of dots.

[0008] With this configuration, the heat sink has the function of a rivet portion, so that the heat sink and the radiation fin lead can be crimped without requiring a special area for the rivet portion. By pressing the outer edge with the projection, the heat sink and the radiation fin lead can be easily pressed.

The measures taken by claim 2 of the present invention are different from the measures taken by claim 1 in that the first side surface of the groove is directed from inside the outer edge of the main surface of the heat sink to the inside of the heat sink. The second side surface is formed substantially perpendicular to the heat sink main surface.

When a force is applied from above the main surface of the heat sink to press the heat sink against the radiating fin lead, the first side surface is formed to have an inclination angle with respect to the main surface. Deformation occurs from the first side surface to the outer edge portion, and the deformed portion is covered with the radiating fin, and the crimped state is maintained. When the second side surface is perpendicular to the main surface, a problem such as a step does not occur in an inner region surrounded by the second side surface. Therefore, it is possible to secure a flat surface for bonding the semiconductor pellet and the heat sink.

According to a third aspect of the present invention, in the vicinity of the radiating fin lead, the projection of the outer edge of the heat sink as viewed from the main surface of the heat sink in a direction perpendicular to the main surface is as follows:
It is characterized in that it does not intersect with the outer edge of the inner lead located near the heat radiation fin lead and arranged along the outer edge of the heat sink.

With this configuration, when the tip of the inner lead near the heat radiation fin and having a short lead length is wire-bonded to the pad of the semiconductor pellet, these inner leads are placed below the inner lead. A mounting table can be installed. With this base, the short inner lead can be fixed, and the oscillation phenomenon that is likely to occur with the short inner lead can be avoided to perform the wire bonding stably.

According to a fourth aspect of the present invention, a heat sink has a main surface and a step portion inserted into a through hole of a heat radiation fin lead, and then the heat radiation fin lead is pressed against the heat sink with a fixing frame. The outer edge of the heat sink is covered with the through-hole of the radiating fin lead and press-bonded by applying mechanical pressure with a metal tool from vertically above the main surface of the heat sink. Here, the metal tool is provided on the heat sink main surface adjacent to the first surface and the first surface having an inclination with respect to the heat sink main surface in the heat sink main direction in order to push out the outer edge of the heat sink main surface. A second surface formed substantially perpendicularly, a surface adjacent to the second surface and parallel to a main surface of the heat sink, and a projection is formed on the first and second surfaces; .

According to this method, when a force is applied from above the main surface to press the heat sink and the radiating fin lead, the second side surface has an inclination angle with respect to the main surface, so that it is relatively weak. The shape of the outer edge can be deformed by force, and this outer edge can be easily covered on the radiation fin lead side, while the second side surface is perpendicular to the main surface, so that the main surface Even if a force is applied from above, no force is directly applied to the second side surface, so that a problem such as a step does not occur in an internal region surrounded by the second side surface. Therefore, it is possible to secure a flat surface for bonding the semiconductor pellet and the heat sink.

According to a fifth aspect of the present invention, there is provided a manufacturing apparatus for installing a radiation fin lead, an inner lead and a heat sink integrated in a wire connection step.
A recess for installing a heat sink, and a wall forming a periphery of the recess, the height of the wall being set such that a surface of the wall parallel to the recess contacts an inner lead near a radiation fin lead. Is set.

By disposing the raised wall below the first inner lead, the deflection of the first inner lead can be eliminated when the capillary presses the first inner lead, and the wire bond can be stably formed. It can be performed.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a main part of a semiconductor device according to an embodiment of the present invention. A in this plan view
A view showing a cross section of this main part at -A 'is shown by a cross-sectional view taken along AA', and a view showing a cross section of this main part at BB 'is shown at BB'.
This is shown in a sectional view.

In FIG. 1, reference numeral 1 denotes a heat sink formed by processing pure copper into a predetermined shape in order to enhance the heat radiation effect, 2 denotes a heat radiation fin formed of a copper alloy metal plate, and 3 denotes a heat radiation fin. This is a radiating fin lead that is continuous. Reference numeral 4 denotes an area showing the outer shape of the package. A plurality of inner leads 5 are arranged around the heat sink 1 inside the region 4 around the heat sink 1, while the inner leads 5 and the radiation fin leads 3 are fixed to each other outside the region 4. Connection region 6 is formed. The connection region 6 is removed after being sealed with a resin, and each lead is separated. Next, a rectangular through hole is formed in the heat radiation fin lead 3 at the center of the package, and this through hole forms the heat radiation fin 2, the inner lead 5, the connection region 6, and the lead 7 from a metal plate. Formed in a pressing step or an etching step. Further, a stepped projection 8 is formed on the heat sink 1, and the outer edge of the main surface on the upper surface of the projection 8, which is a surface for bonding the semiconductor pellet, is formed by the through hole of the radiation fin lead. It has a shape along the shape of the inner edge. The heat sink 1 and the radiating fin lead 3 are crimped at a step just below the main surface.
A cross section of the crimped shape is shown in an enlarged view of a part of the AA ′ cross-sectional view.

In this enlarged view, a groove 9 is formed inside the outer edge of the main surface of the projection 8, and this groove 9 is
And a second side surface 11. The first side surface 10 has a predetermined angle of inclination with respect to the main surface, and the second side surface 11 is perpendicular to the main surface. The first and second side surfaces are formed by strongly pressing a convex tooth profile corresponding to the side surface against the main surface of the heat sink. After the heat radiation fin lead 3 is pressed against the step portion of the heat sink 1, the tooth shape is pressed against the main surface of the heat sink. After being press-bonded in this way, the metal of the heat sink protrudes to the radiation fin lead side by about 0.1 mm at the maximum. On the other hand, the protrusion 8
Of the radiating fin lead 3 is 0.05
mm. Here, since no lateral force is applied to the region surrounded by the second side surface, the main surface of this region is flat. The semiconductor pellet is bonded to this flat surface.

FIG. 2 is an enlarged view of FIG. FIG. 2 (a)
FIG. 2 is an enlarged view of a cross section of the groove described in FIG.
(B) is an enlarged view of a cross section of a groove showing another embodiment.

In FIG. 2B, the second side surface 11 has an inclination with respect to the main surface. This inclination causes a bulge from the groove 9 toward the inside of the projection 8. Since the protrusion occurs in a relatively small area, an area for bonding the semiconductor pellet can be secured. However, FIG.
As shown in (a), it is preferably substantially perpendicular to the main surface.

FIG. 3 is a diagram showing a cross section and a plane of a semiconductor device according to an embodiment of the present invention.

FIG. 3C is a plan view of the resin-sealed semiconductor device as viewed from above, and FIG.
FIG. 3C is a view showing a cross section taken along line AA ′ of FIG.
FIG. 4 is a diagram showing a cross section taken along line BB ′ of FIG.

In FIG. 3A, the semiconductor pellet 20
Is bonded to the main surface of the protrusion 8 of the heat sink 1, while the inner lead 5 for signal transmission is electrically separated from the heat sink 1. The semiconductor pellet 20 and the inner lead 5 are connected by a wire 22. Reference numeral 21 denotes a resin-sealed package in which the semiconductor pellet 20, the heat sink 1, the inner lead 5, and the like are built.

In FIG. 3B, the radiation fin leads 3
Are pressed against the stepped portion of the heat sink 1, and the radiation fins 2 continuous with the radiation fin leads 3 are outside the package 21 and are bent.

As described above, since the semiconductor pellet 20 is directly bonded to the main surface of the projection 8 of the heat sink 1, the conventional tab is unnecessary, and the structure can be simplified. Further, since the heat radiation fins 2 are pressure-bonded to the step portions of the heat sink 1, the semiconductor pellets 2
The heat generated at 0 is efficiently discharged to the outside through two paths of the heat sink and the radiation fin.

When the package outer dimensions of FIG. 3C corresponding to 28 pins are 18 mm and 11 mm, an allowable loss of about 7 W is obtained at room temperature by using a structure in which pure copper is used for the heat sink and a copper alloy is used for the radiating fin leads. Can be.

FIG. 4 is a diagram showing a plane and a cross section of the heat sink of FIG. In the plan view, a cross section taken along the line CC ′ is shown by a cross section taken along the line CC ′, and a cross section taken along the line DD ′ is shown by a cross section along the line DD ′.

In the plane figure of FIG. 4, a concave portion is formed with respect to a rectangle in a region 30 surrounded by a broken line, and the tip of an inner lead having a short lead length described later is located in this region. As shown in the CC ′ cross-sectional view, the length from the main surface of the protrusion 8 to the surface of the adjacent step is 0.3 mm, and the length from the surface of the heat sink adjacent to the surface of the step is: 0.2 mm, and the length from the surface to the back surface of the heat sink is 0.8 mm. Further, as shown in the CC ′ and DD ′ cross-sectional views, the dimensions of the main surface of the protruding portion 8 are 4.7 mm and 3.8 mm, and the portion excluding the shape of the convex portion of the step portion is provided. Are 5.3 mm and 5.4 mm.

FIG. 5 is a plan view of the inner lead 5, the lead 7, the radiation fin 2 and the radiation fin lead 3 of FIG. A square through hole 40 is formed in the center of the radiation fin lead 3.
The through hole 40 has a shape corresponding to the outer edge of the main surface of the projection 8 of the heat sink 1 in FIG.

Further, inner leads 41 and 42 are formed in a region corresponding to the region 30 in FIG. The inner leads 41 and 42 are located in a region where the shape of the heat radiation fin lead 3 is cut off, and secure more wiring leads. These inner leads 41, 4
2 is relatively short with respect to the length of the other inner leads. Therefore, the inner lead 4
When a force due to the ultrasonic vibration is applied to the distal ends of the first and the second 42, a relatively strong repulsive force due to the vibration is likely to be generated with the connecting portion 6 as a fulcrum.

FIG. 6 is a view showing one embodiment of a method of manufacturing a semiconductor device according to the present invention. In FIG. 6A,
The heat sink 1 is installed on the fixing base 50, and the heat radiation fin leads 3 are fitted into the projections 8.

In FIG. 6B, the radiation fin leads 3
Are pressed against the step of the projection 8. In this state, the radiation fin lead 3 can be easily removed. FIG. 6C shows a state where the fixing frame 51 is pressed from above the radiation fin lead 3, and the tool 52 is pressed from above to the projection 8 in a state where the radiation fin lead 3 and the heat sink 1 are fixed. It shows the situation. In the enlarged view of the tip of the tool 52, the tool has a first surface 53 and a second surface 54 to form a projection 55. The first surface 53
The second surface 53 has a predetermined inclination angle with respect to the main surface of the heat sink, and is perpendicular to the main surface of the heat sink.
An acute angle is formed at a portion where the first surface 53 and the second surface 54 intersect. FIG. 6D illustrates a state in which the protrusion 55 is pressed near the outer edge of the main surface of the heat sink 1. The protrusion 55 cuts into the heat sink, and the outer edge of the main surface of the heat sink 1 is covered on the heat radiation fin lead 3 side. First surface 53 and second surface of projection
With the surface 54, the groove 9 having the first side surface 10 and the second side surface 11 is formed at the outer edge of the heat sink.

FIG. 7 is a view showing an embodiment of the manufacturing apparatus of the present invention. FIG. 7A shows an inner lead 42 based on a cross section GG ′ of a main part of the semiconductor device of FIG.
FIG. 7B is a diagram for comparing the configuration and operation.

In FIG. 7A, the heat sink 1 and the radiating fin lead 3 integrated on the upper surface of the fixed base 60 are installed, and the inner lead 42 is installed on the upper surface of a wall 61 connected to the fixed base 60. Here, the wire 22 is passed through the hollow capillary 62, and after the tip of the wire is pressed against the semiconductor pellet 20 by ultrasonic vibration,
Further, another portion of the wire 22 is crimped to the distal end portion of the inner lead 42 to perform the wire connection. Since the surface of the wall body 61 is in contact with the surface of the inner lead 42 opposite to the surface of the capillary 62, wire connection can be performed with the inner lead 42 stably installed. FIG.
(B) shows a case where a gap 63 exists between the surface of the fixed base 60 and the surface opposite to the surface where the capillary 62 contacts the inner lead 42. Because of the gap 63, a spring is formed with a portion 64 where the inner lead 42 contacts the end of the wall 61 as a fulcrum. For this reason, the inner lead 42 is likely to be vibrated by the spring at the time of crimping by the ultrasonic vibration, which causes a problem in the wire connection. As a result of the comparative test, the non-defective rate of the wire connection in FIG. 7B was 50% or less, while the non-defective rate of the wire connection in FIG. 7A was about 100%.

FIG. 8 shows a plan view and a sectional view of the manufacturing apparatus of FIG. FIG. 8A is a plan view of the entire fixing base 60, and FIG. 8B is an enlarged view showing a main part of the present invention. Here, a section taken along the line EE 'is shown in a sectional view taken along the line EE', and a section taken along the line FF 'is shown in a sectional view taken along the line FF'.

In FIG. 8A, a bolt penetrates the hole 70 and is fixed to the wire bonding apparatus main body. FIG. 8 (a)
Has a shape corresponding to the two comb leads, and has a concave portion 71 corresponding to the planar shape of the heat sink in FIG.

FIG. 8B is an enlarged view of the vicinity of the concave portion 71. A through hole 72 penetrating the fixing table 60 is provided at the center of the concave portion 71.
Is opened, and the heat sink 1 is inserted through the through hole.
Is vacuum-sucked. Corresponding to the area 30 in FIG.
A convex portion 73 is formed in the concave portion 71 toward the inside of the concave portion, and the tips of the inner leads 41 and 42 are held by the surface of the convex portion 73 when a wire is connected. The length from the bottom surface of the heat sink 1 to the bottom surface of the radiation fin lead 3 is 1.0 mm, and the length from the plane of the concave portion 71 to the plane of the convex portion 73 is set to 1.0 mm corresponding to this length. Is done. In addition, the length of the gap between the inner lead 5 and the plane of the heat sink located under the inner lead 5 is set to 0.
2 mm, and the step between the plane of the portion adjacent to the concave portion 71 and excluding the convex portion 73 and the surface of the convex portion 73 is set to 0.2 mm corresponding to this length.

FIG. 9 is a perspective view showing the position of the fixed base in the wire bonding apparatus. The fixed base 60 is fixed to the fixed frame 8.
The wire is connected by a capillary 62 crimped to the tip of the arm 81. Fixed frame 8
0 is provided with a hole 82 for vacuum suction,
The end of the hole 82 communicates with the through hole 72.

[0041]

As described above, according to the present invention, a groove is formed in the outer edge of the heat sink by applying a mechanical pressure to the outer edge of the main surface of the heat sink, and the outer edge of the groove is crimped to the radiation fin lead. The heat sink and the heat radiation fin lead can be crimped without requiring a special area for the rivet part, and the heat sink and the heat radiation fin lead are easily crimped by pressing the outer edge of the heat sink with the projection. Semiconductor device can be realized.

Further, the first side surface of the groove is formed so as to be inclined from the inside of the outer edge of the heat sink main surface toward the inside of the heat sink, and the second side surface is formed of the main surface. As a result, the main body device having a flat surface for bonding the semiconductor pellet and the heat sink can be realized.

Further, in the vicinity of the radiating fin lead, the projection of the outer edge of the heat sink as viewed from the main surface of the heat sink in a direction perpendicular to the main surface is arranged along the outer edge of the heat sink near the radiating fin lead. By not intersecting the outer edges of the inner leads, it is possible to realize a semiconductor device in which a base on which these inner leads are mounted can be installed below the inner leads.

Further, a first surface which forms an inclination with respect to the main surface from the inside of the outer edge of the main surface of the heat sink toward the inside of the heat sink, is formed adjacent to the first surface and substantially perpendicular to the main surface of the heat sink. A metal tool having a second surface and a surface adjacent to the second surface and parallel to the main surface of the heat sink, and forming a projection on the first and second surfaces; By pressing the tool against the heat sink main surface from above to generate the second mechanical pressure, the shape of the outer edge can be deformed by a relatively weak force. Since the second side surface is perpendicular to the main surface, the semiconductor device can be easily covered on the lead side. Therefore, a method of manufacturing a semiconductor device which secures a flat surface for bonding a semiconductor pellet and a heat sink is implemented. It can be.

Further, a concave portion for installing a heat sink,
A wall forming the periphery of the recess, and the height of the wall is set such that the upper surface of the wall parallel to the recess is in contact with the inner lead near the radiation fin lead, so that the capillary is When the first inner lead is pressed, the bending of the first inner lead can be eliminated, and a semiconductor device manufacturing apparatus capable of performing stable wire bonding can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a main part of a semiconductor device according to an embodiment of the present invention;

FIG. 2 is an enlarged view of FIG. 1;

FIG. 3 is a diagram showing a cross section and a plane of a semiconductor device according to an embodiment of the present invention;

FIG. 4 is a diagram showing a plane and a cross section of the heat sink of FIG. 1;

FIG. 5 is a plan view of the inner lead, the lead, the radiation fin, and the radiation fin lead of FIG. 1;

FIG. 6 is a diagram showing one embodiment of a method for manufacturing a semiconductor device of the present invention.

FIG. 7 is a diagram showing an embodiment of the manufacturing apparatus of the present invention.

8 shows a plan view and a cross section of the manufacturing apparatus of FIG. 7;

FIG. 9 is a perspective view showing the position of the fixing base in the wire bonding apparatus.

FIG. 10 shows a conventional semiconductor device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 heat sink 2 heat radiation fin 3 heat radiation fin lead 4 region 5 inner lead 6 connection region 7 lead 8 protrusion 9 groove 10, 11 side surface 20 semiconductor pellet 21 package 22 wire 30 region 40 through hole 41, 42 inner lead 50 fixing base 51 fixed Frame 52 Tool 53, 54 Surface 55 Projection 60 Fixing base 61 Wall 62 Capillary 63 Gap 64 Portion 70 Hole 71 Depression 72 Through hole 73 Convex 80 Fixing frame 81 Arm 82 Hole 100 Semiconductor pellet 101 Bonding layer 102 Tab 103 Radiation fin Lead 104 resin package 105 radiating fin 106 heat sink 107 rivet part 108 coupling hole

Claims (5)

[Claims] 1. A heat sink having a stepped step formed on a side surface of a semiconductor pellet on one main surface, and a stepped step formed on a side surface of the semiconductor pellet, the shape including the step along the shape of the step adjacent to the main surface. And a radiating fin lead having a through hole formed in the main surface of the metal plate as described above, wherein the through hole is press-fitted to a step on the side surface of the heat sink, and the semiconductor pellet, the heat sink and the radiating fin lead are sealed. A semiconductor device, wherein a groove is formed in an outer edge portion of the heat sink by applying a mechanical pressure to an outer edge portion of the heat sink main surface, and the outer edge portion of the groove is crimped to the heat radiation fin lead. . 2. A first side surface of the groove is formed so as to be inclined from the inside of an outer edge of the heat sink main surface to an inside direction of the heat sink with respect to the main surface, and a second side surface is formed by the main surface. 2. The device according to claim 1, wherein the first member is formed substantially perpendicular to the first member.
13. The semiconductor device according to claim 1. 3. A projection of an outer edge of the heat sink viewed from a main surface of the heat sink in a direction perpendicular to the main surface in the vicinity of the heat radiation fin lead, is disposed along the outer edge of the heat sink in the vicinity of the heat radiation fin lead. A semiconductor device which does not intersect the outer edge of the inner lead. 4. A heat sink having a step-shaped step on the side surface with respect to the main surface, and a through hole formed in the main surface of the metal plate so as to include the shape along the shape of the step adjacent to the main surface. A heat radiation fin lead formed on the heat sink, the heat radiation fin lead being pressed against the heat sink by a first mechanical pressure, and then applying a second mechanical pressure from above the main surface vertically. A method of manufacturing a semiconductor device in which an outer edge of the heat sink fin is pressed into a through-hole of the heat radiation fin lead, wherein a first surface is formed to be inclined from the inside of the outer edge of the main surface of the heat sink toward the heat sink toward the main surface. A second surface adjacent to the first surface and formed substantially perpendicular to the main surface of the heat sink; and a second surface adjacent to the second surface and parallel to the main surface of the heat sink. In terms of Comprising a metal tool to form the raised, a method of manufacturing a semiconductor device, characterized in that for generating the second mechanical pressure from the vertical upward pressure to the tool to the heat sink main surface of the heat sink main surface. 5. A manufacturing apparatus for installing a radiating fin lead, an inner lead, and a heat sink integrated in a wire connection step, comprising: a recess for installing a heat sink; and a wall forming a periphery of the recess. A height of the wall body is set such that an upper surface of the wall body parallel to the recess is in contact with an inner lead near a radiation fin lead.