JP3715590B2 - Insert molding case and semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insert molding case and a semiconductor device to which the insert molding case is applied, and more particularly to a technique for firmly fixing a terminal to a case body in an insert molding case.
[0002]
[Prior art]
FIG. 7 is a plan view for explaining a power semiconductor device 750 according to the first prior art. Moreover, the enlarged view of the part 8 enclosed with the broken line in FIG. 7 is shown in FIG. 8, and sectional drawing in the 9-9 line in FIG. 8 is shown in FIG.
[0003]
In the power semiconductor device 750, an insulating substrate 756 made of, for example, ceramic is disposed on the heat dissipation plate 757 via solder. A circuit pattern 754 is formed on the insulating substrate 756, and a plurality of power semiconductor chips 753 are arranged on the circuit pattern 754 via solder. A frame-shaped insert-molded case (hereinafter also simply referred to as “case”) 800 is disposed on the heat dissipation plate 757 so as to surround the power semiconductor chip 753.
[0004]
The case 800 includes an insulating case body 810 made of, for example, resin, and a plurality of terminals 850 inserted into the case body 810. The bonding surface 853 of the terminal 850, the power semiconductor chip 753, and the circuit pattern 754 are connected to each other by a wire 752 in a predetermined manner.
[0005]
As shown in FIGS. 8 and 9, the terminal 850 has a bulge portion 855 whose thickness is reduced by a bulge process at a part of the tip side portion, and the bulge portion 855 has a level difference (for example, 0. 2 to 0.3 mm). The terminal 850 is embedded (inserted) in the case body 810 such that the bush portion 855 is embedded in the case body 810 and the bonding surface 853 is exposed at the same level as the surface of the case body 810. ing).
[0006]
Next, FIG. 10 shows a plan view of the vicinity of the terminal 950 of the insert molding case 900 according to the second prior art, and FIG. 11 shows a cross-sectional view taken along line 11-11 in FIG. Case 900 is applied to power semiconductor device 750 instead of case 800 described above. The molding die for the case 900 is provided with a guide pin, and the guide pin guides and holds the terminal 950 during molding. For this reason, hereinafter, the case 900 is also referred to as a pin guide type case 900.
[0007]
As shown in FIGS. 10 and 11, the case 900 has a hole 912 caused by the above-described guide pin, and the electrode 950 is exposed in the hole 912. Also in the case 900, the bonding surface 953 of the terminal 950 is formed so as to have the same height level as the surface of the case main body 910.
[0008]
The cases 800 and 900 are filled with silicon gel (not shown), and the power semiconductor chip 753 and the like are sealed.
[0009]
[Problems to be solved by the invention]
As described above, the case 800 is insert-molded so that the bonding surface 853 of the terminal 850 is at the same height as the surface of the case main body 810, and therefore the gap between the molding die and the bush portion 855 is the bonding surface 853. This corresponds to the above-described step difference (for example, 0.2 to 0.3 mm) between the heel and the bush portion 855. Due to such a narrow gap, there may occur a case where the resin for the case main body 810 is not sufficiently disposed (filled) on the bush portion 855 as shown in FIG. 9, that is, the bush portion 855 is not sufficiently buried. . In such a case, since the terminal 850 is not sufficiently held by the case main body 810, for example, the terminal 850 is lifted and wire bonding cannot be stably performed. In other words, the strength of wire bonding becomes insufficient.
[0010]
Further, since the terminal 850 needs to process the bush portion 855, the processing cost makes the case 800 and the semiconductor device 750 expensive.
[0011]
On the other hand, in the pin guide type case 900, air in the guide pin hole 912 forms bubbles in the silicon gel, which may cause problems in the semiconductor device due to the bubbles.
[0012]
Further, since it is necessary to provide guide pins with high precision in the molding die for case 900, case 900 and semiconductor device 750 become expensive.
[0013]
The present invention has been made in view of such a point, and a first object thereof is to provide an insert molded case in which terminals are firmly fixed to a case main body at a lower cost than conventional cases 800 and 900.
[0014]
Furthermore, a second object of the present invention is to provide a semiconductor device at a low cost by using an insert molding case that can realize the first object.
[0015]
[Means for Solving the Problems]
The insert-molded case according to claim 1 is an insert-molded case that houses an electric circuit to form a semiconductor device, and has an insulating case body, a bonding surface, and a side surface that follows the bonding surface, A terminal inserted in the case main body so that the bonding surface is exposed, and the case main body is provided on both sides of the bonding surface in the width direction of the terminal and on the side surface following the bonding surface. And includes a projecting portion that is in contact with and is not in contact with the bonding surface and projecting further than that, and when the distance between the projecting portions is L1 and the width of the terminal is L2, L1 ≦ L2 and L1 ≈L2 is satisfied.
[0016]
The insert molding case according to claim 2 is the insert molding case according to claim 1, wherein the side surface of the terminal includes a sagging surface generated by press shear following the bonding surface, and the sagging surface. The protruding portion is in contact with.
[0017]
According to a third aspect of the present invention, there is provided a semiconductor device according to the first or second aspect, and an electric circuit that is accommodated in the insert molded case and connected to the bonding surface of the terminal by a wire. And comprising.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a plan view for explaining a power semiconductor device or a power semiconductor module 50 according to an embodiment of the present invention. The power semiconductor device 50 includes a heat sink 57, an insulating substrate 56 made of, for example, ceramic, an electric circuit 51, a wire 52, a frame-shaped insert-molded case (hereinafter also simply referred to as “case”) 100, Is included.
[0019]
Specifically, the insulating substrate 56 is disposed on the heat radiating plate 57 via solder (not shown). A conductive circuit pattern 54 is formed on the insulating substrate 56 so as to face the heat sink 57 with the insulating substrate 56 interposed therebetween, and a plurality of power semiconductor chips 53 are not formed on the circuit pattern 54. It arrange | positions through the solder of illustration. The power semiconductor chip 53 is, for example, a switching element, and an IGBT (insulated gate bipolar transistor) is an example. The plurality of power semiconductor chips 53 and the circuit pattern 54 are connected to each other by wires 55. That is, the electric circuit 51 is formed on the insulating substrate 56 with the power semiconductor chip 53, the circuit pattern 54, and the wire 55. A resist 58 for positioning the power semiconductor chip 53 is disposed on the circuit pattern 54.
[0020]
And the heat sink 57 is arrange | positioned so that one opening of the frame-shaped case 100 may be block | closed, and the box or the container body is formed by the case 100 and the heat sink 57 by this. At this time, the case 100 and the heat radiating plate 57 are arranged in the box, in other words, in the frame-like case 100 so that the electric circuit 51 is accommodated.
[0021]
The case 100 includes a case main body 110 made of an insulating material made of resin, for example, and forming a frame, and a plurality of terminals 150 inserted into the case main body 110, and a bonding surface 153 (see FIG. 2 to 5) and the electric circuit 51 are electrically connected by a wire 52. The case 100 will be described in detail later.
[0022]
The power semiconductor device 50 further includes silicon gel, a lid, and a circuit board. Specifically, the box formed by the case 100 and the heat radiating plate 57 is filled with, for example, silicon gel (not shown) so as to cover the electric circuit 51 and is further covered with a lid (not shown). In the power semiconductor device 50, a circuit board (not shown) is connected to the tip of the first portion 151 (FIGS. 2 to 5) of the terminal 150 in the case 100.
[0023]
Next, the case 100 will be described in detail with reference to FIGS. 2 is an enlarged view of a portion 2 surrounded by a broken line in FIG. 1, and FIG. 3 is a view of the case 100 seen from the direction of the arrow 3 in FIG. 2 (hatching is given for explanation). 4 is a cross-sectional view taken along line 4-4 in FIG. 2, and FIG. 5 is a cross-sectional view taken along line 5-5 in FIGS. In order to avoid complication of the drawings, for example, in FIG. 3 and FIG. 4, a part of the case main body 110 (portion facing the first portion 151 of the terminal 150) is omitted.
[0024]
Here, for simplicity of explanation, the terminal 150 is made of a plate-like member bent into an L shape, and one side and the other side of the L shape are referred to as a first portion 151 and a second portion 152, respectively. .
[0025]
The terminal 150 is arranged so that the plate-like main surface of the first portion 151 faces the side wall portion of the frame body and the tip of the second portion 152 protrudes toward the inside of the frame body inside the frame body. The vicinity of the bent portion of the terminal 150 is embedded (inserted) in the case main body 110.
[0026]
At least the tip of the first portion 151 protrudes from the surface of the case body 110. In the power semiconductor device 50, since the tip of the first portion 151 is connected to a circuit board (not shown) in the case body 110, the case where the first portion 151 is lower than the side wall portion of the case body 110 is shown in FIG. Although illustrated, it is also possible to make the tip higher than the side wall portion of the case body 110 and use it as an external lead terminal.
[0027]
On the other hand, one main surface of the plate-shaped member in the second portion 152 forms a bonding surface 153, and the second portion further has a plate-shaped main surface (hereinafter also referred to as a back surface) 154 facing the bonding surface 153. And a side surface 155 following the back surface 154 and the bonding surface 153 between the back surface 154 and the bonding surface 153. Of the side surfaces 155, the end surface in the length direction of the second portion 152 is also referred to as a tip surface 156.
[0028]
The second portion 152 is embedded (inserted) in the case body 110 so that the bonding surface 153 is exposed. That is, the back surface 154 and the side surface 155 of the second portion 152 are in contact with the case main body 110. 2 and the like illustrate the case where the tip surface 156 of the second portion 152 is exposed, but the tip surface 156 may not be exposed.
[0029]
In particular, in the case main body 110, a portion 111 in contact with the side surface 155 of the second portion 152 protrudes from the bonding surface 153, and the portion 111 and the bonding surface 153 are second in the plan view of the bonding surface 153 (see FIG. 2). The portions 152 are alternately arranged in the width direction DW. Hereinafter, the portion 111 is referred to as a “projection 111”. That is, the protrusions 111 are provided on both sides of the second part 152 in the width direction DW of the second part 152, respectively. The protrusions 111 are in contact with the side surface 155 of the second part 152 and protrude from the bonding surface 153. Yes. The protrusion amount (protrusion height) a of the protrusion 111 with respect to the bonding surface 153 is set so that the wire bonding apparatus can perform wire bonding work, and is, for example, 0.25 mm or less.
[0030]
In addition, the distance L1 between the protrusions 111 and the width L2 of the second portion 152 are set to be equal (L1 = L2) or substantially equal (L1≈L2). Here, in plan view of the bonding surface 153 in the second portion 152 (see FIG. 2), the vicinity of the distal end surface 156 or the distal end side portion 152A is narrower than the bent portion side portion 152B. Both of 152A and the bent portion side portion 152B satisfy the above-described L1 = L2 (or L1≈L2). Note that the narrow distal end portion 152A can reduce the load on the distal end portion 152A when the terminal 150 is press-sheared. The width L2 of the second portion 152 is, for example, about 0.8 mm at the distal end side portion 152A and about 1.4 mm at the bent portion side portion 152B.
[0031]
As described above, the protruding portion 111 of the case main body 110 is in contact with the side surface 155 of the terminal 150 and protrudes from the bonding surface 153. Further, the distance L1 between the protruding portions 111 and the width L2 of the second portion 152 of the terminal 150 are (Roughly) equal. For this reason, the resin for the case main body 110 as the protruding portion 111 is sufficiently disposed on both sides of the second portion 152 in the width direction DW as compared with the conventional cases 800 and 900, and the protruding portion 111 extends the bonding surface 153 in the width direction. It arrange | positions so that it may pinch | interpose in DW. Accordingly, the terminal 150, particularly the bonding surface 153 can be firmly fixed to the case body 110 while the bonding surface 153 is sufficiently secured, so that wire bonding can be stably performed to increase the bonding strength. Can do. As a result, by using the case 100, productivity and yield can be improved, and the power semiconductor device 50 can be provided at low cost.
[0032]
In addition, according to the case 100, it is not necessary to perform the lip processing on the terminal 850 unlike the conventional case 800, or to provide the guide pin with high accuracy in the molding die unlike the conventional case 900. That is, the power semiconductor device 50 can also be made inexpensive by reducing the costs for the bushing and the guide pin arrangement. In addition, since the case 100 does not have the guide pin hole 912 itself, bubbles due to the hole 912 are not formed in the silicon gel, and thus the bubbles may cause a problem in the power semiconductor device 50. Absent.
[0033]
Now, when the terminal 150 is formed by press shearing, a sag surface 157 is formed at the edge (edge) of the terminal 150 as shown in FIG. 6 corresponding to the enlarged views of FIGS. Here, the sagging surface 157 is treated as a part of the side surface 155. By using the sagging surface 157, the terminal 150 can be more firmly fixed to the case body 110.
[0034]
Specifically, the plate-like main surface following the sag surface 157 (in other words, the side close to the sag surface 157) is selected as the bonding surface 153, and the projecting portion 111 is in contact with (covers) the sag surface 157. As). The width of the sag surface 157 in the plan view of the bonding surface 153 (dimension in the width direction DW) is, for example, about 0.2 mm. At this time, the width L1 between the protrusions 111 and the width L2 of the second portion 152 of the terminal 150 are Are approximately equal (L1≈L2), but L1 is slightly smaller than L2 (L1 <L2, where L2−L1 = 0.4 mm).
[0035]
By forming the protruding portion 111 on the sag surface 157 in this way, the end portion in the width direction DW of the second portion 152 is embedded in the case main body 110, so that the thickness of the plate-like member forming the terminal 150 is increased. The second part 152 is also fixed by the protrusion 111 in the direction DT. For this reason, the terminal 150 and hence the bonding surface can be more firmly fixed to the case body 110, and the stability and bonding strength of wire bonding can be further increased. At this time, such an effect is obtained by a simple means of selecting the plate-like main surface following the sag surface 157 in the press-sheared terminal 150 as the bonding surface 153.
[0036]
Since the width of the sag surface 157 is smaller than the width L2 of the second portion 152 as in the above example, the bonding surface 153 is sufficiently secured.
[0037]
By the way, the terminal 150 may be a control terminal in the power semiconductor device 50, or may be a high voltage / high current terminal having a wider width than the control terminal.
[0038]
The electric circuit 51 may include a low-voltage semiconductor chip instead of or in addition to the power semiconductor chip 53, that is, the application range of the case 100 is not limited to the power semiconductor device 50.
[0039]
【The invention's effect】
According to the first aspect of the present invention, the protruding portion of the case body is in contact with the side surface of the terminal and protrudes from the bonding surface, and the distance L1 between the protruding portions and the terminal width L2 are L1 ≦ L2 and L1≈. Satisfy L2. For this reason, protrusions of sufficient size (amount) are arranged on both sides of the terminal in the width direction, and the protrusions are arranged so as to sandwich the bonding surface in the width direction. Accordingly, since the terminals, particularly the bonding surface, are firmly fixed to the case body while sufficiently securing the bonding surface, stable wire bonding can be achieved and the bonding strength can be increased. At this time, in the insert molding case of the present invention, it is not necessary to perform a bulge process on the terminal or to provide a guide pin on the molding die, so that the above effect can be obtained at a low cost. In addition, since no guide pin is used, a guide pin hole is not formed in the case body, and therefore, a semiconductor device that does not suffer from problems caused by air in the hole can be provided.
[0040]
According to the second aspect of the present invention, since the projecting portion is in contact with the sag surface, the end portion in the width direction of the terminal is embedded in the case body, whereby the terminal is also fixed in the thickness direction by the projecting portion. Is done. For this reason, a terminal and hence a bonding surface can be more firmly fixed to the case body. Therefore, the stability of wire bonding and the bonding strength can be further increased. Moreover, in the terminal manufactured by press shear, the above effect can be obtained by a simple means of selecting a surface following the sag surface as a bonding surface.
[0041]
According to the invention of claim 3, since the insert molded case of claim 1 or claim 2 is used, productivity and yield are improved, and as a result, an inexpensive semiconductor device can be provided.
[Brief description of the drawings]
FIG. 1 is a plan view for explaining a power semiconductor device according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion 2 surrounded by a broken line in FIG.
FIG. 3 is a view of an insert molding case as seen from the direction of an arrow 3 in FIG. 2;
4 is a cross-sectional view taken along line 4-4 in FIG.
FIG. 5 is a cross-sectional view taken along line 5-5 in FIGS.
FIG. 6 is an enlarged view for explaining the insert molding case according to the embodiment of the present invention.
FIG. 7 is a plan view for explaining a power semiconductor device according to a first prior art.
FIG. 8 is an enlarged view of a portion 8 surrounded by a broken line in FIG.
9 is a cross-sectional view taken along line 9-9 in FIG.
FIG. 10 is a plan view for explaining an insert molding case according to a second prior art.
11 is a cross-sectional view taken along line 11-11 in FIG.
[Explanation of symbols]
50 Power Semiconductor Device, 51 Electrical Circuit, 52 Wire, 100 Insert Molded Case, 110 Insulating Case Body, 111 Protruding Portion, 150 Terminal, 153 Bonding Surface, 155 Side Surface, 157 Sag Surface, DW Width Direction, L1 Protruding Portion Distance between, the width of the second part of the L2 terminal.

Claims (3)

An insert molding case that houses an electric circuit to form a semiconductor device,
An insulating case body,
A bonding surface and a side surface following the bonding surface, and a terminal inserted in the case body so that the bonding surface is exposed, and
The case body includes protrusions that are provided on both sides of the bonding surface in the width direction of the terminal, are in contact with the side surface following the bonding surface, and protrude beyond the bonding surface without contacting the bonding surface. And
When the distance between the protrusions is L1, and the width of the terminal is L2, L1 ≦ L2 and L1≈L2 are satisfied.
Insert molded case. The insert molded case according to claim 1,
The side surface of the terminal includes a sag surface generated by press shear following the bonding surface,
The protrusion is in contact with the sag surface;
Insert molded case. The insert molding case according to claim 1 or 2,
It is accommodated in the insert molding case, and comprises an electric circuit connected to the bonding surface of the terminal by a wire,
Semiconductor device.

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