JP2012049195A - Semiconductor device and lead frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device in which a plate heat sink, a terminal board and a heat generator are sequentially layered in a thickness direction and encapsulated by a mold resin, which inhibits deterioration in quality and heat dissipation.SOLUTION: The lead frame 1 for semiconductor device manufacturing comprises terminal strips 2, 3, a coupling plate 4 for fixing the terminal strips 2, 3 to a heat sink 6, and a plate-like frame part 5 integrally linking the terminal strips 2, 3 and the coupling plate 4. The coupling plate 4 protrudes from the frame part 5 in a thickness direction of the frame body 5 such that a front end portion 42 of the coupling plate 4 is disposed below under surfaces of arrangement parts 22 of the terminal strips 2, 3 on which heat generators are mounted. The coupling plate 4 includes engaging parts for engagement with a mold resin.

Description

  The present invention relates to a semiconductor device and a lead frame used for manufacturing the semiconductor device.

  2. Description of the Related Art Conventionally, a semiconductor device that conducts a large current such as a diode product is energized like a semiconductor chip such as a diode on the surface of a substrate stacked on a thick heat sink as in Patent Document 1, for example. There is a structure in which a heating element that generates heat and a conductive terminal board that is electrically connected to the heating element through a substrate are fixed. In this semiconductor device, the heat sink, the insulating substrate, the terminal board, and the heating element are sealed with a mold resin so that only the lower surface of the heat sink is exposed. In this semiconductor device, the substrate is formed by forming a wiring pattern for electrically connecting the heating element and the terminal plate on the upper surface of an insulating plate made of an electrically insulating material such as ceramics.

  By the way, in this type of semiconductor device, the formation of the wiring pattern described above is omitted, and an insulating plate, a terminal plate for external terminals, and a heating element are sequentially stacked on the heat sink with a bonding agent such as solder. Some are fixed. In this semiconductor device, the heat generated in the heating element during energization can be released from the terminal plate to the heat sink via the insulating plate material. When manufacturing this semiconductor device, each component of a heat sink, an insulating substrate, a terminal board, and a heating element is separately prepared in advance. Then, while relatively positioning the plurality of components using a jig, the plurality of components are superposed in the order described above, and then the components are fixed to each other by solder reflow or the like.

JP 2009-238804 A

  However, when stacking multiple components, the relative position of multiple components is easily affected by the dimensional accuracy of each component and the dimensional accuracy of the jig. As a result, the relative positional accuracy of the plurality of components is greatly reduced. In this case, there is a high possibility that the bonding agent and the heating element are cracked in the manufactured semiconductor device, and the quality of the semiconductor device is deteriorated. For example, when a crack occurs in the bonding agent, heat generated in the heating element cannot be efficiently released to the heat sink, and a malfunction may occur in the semiconductor device.

  In the above conventional semiconductor device, in order to improve the adhesion between the heat sink and the mold resin, the mold resin covers not only the upper surface of the heat sink but also the side surface, or the heat sink itself has a complicated shape that engages with the mold resin. I do. However, if the side surface of the heat sink is covered with the mold resin, the heat sink must be formed as small as the volume of the mold resin covering the side surface of the heat sink. As a result, there is a problem that the heat capacity of the heat sink is reduced and the heat dissipation performance of the semiconductor device is lowered. Further, when a complicated shape for engagement is formed on the heat sink, there is a problem that the manufacturing cost of the semiconductor device increases.

  The present invention has been made in view of the above-described circumstances, and provides a semiconductor device capable of suppressing deterioration in quality and heat dissipation, and also capable of reducing manufacturing cost, and a lead frame used for manufacturing the semiconductor device. Objective.

In order to solve this problem, a lead frame of the present invention includes a plate-shaped heat sink, a terminal plate arranged on the upper surface of the heat sink with a space, and an upper surface of a plate-shaped arrangement portion of the terminal plate. A heat generating element fixed to a terminal plate and electrically connected to the terminal plate, and a heat sink, a terminal plate, and a mold resin for sealing the heat generating element are used for manufacturing a semiconductor device, and the terminal plate and the heat sink And a plate-like frame body portion that integrally couples them, and the connection plate protrudes in the thickness direction with respect to the frame body portion, so that the connection plate The front end is located below the lower surface of the arrangement part, and the connection part is formed with an engagement part for engaging with the mold resin.
In addition, the said heat generating body has shown the various electric / electronic components which are not limited to a semiconductor element.

  When a semiconductor device is manufactured using this lead frame, first, the tip of the connecting plate may be fixed to the upper surface of the heat sink so that the terminal plate placement portion is positioned on the upper surface of the heat sink. In this state, the heat sink and the terminal plate are integrally fixed via the frame portion of the lead frame and the connecting plate. Further, when the semiconductor device is manufactured, the heating element may be fixed to the upper surface of the terminal plate arrangement portion. Thereafter, the heat sink, the heating element, and the terminal frame and connecting plate of the lead frame may be sealed with a mold resin. Note that the terminal plate and the connecting plate can be electrically separated by cutting off the frame portion of the lead frame after forming the mold resin.

If the semiconductor device is manufactured in this way, the heat sink and the terminal plate can be directly fixed as compared with the conventional configuration in which the heat sink and the terminal plate are fixed via the insulating substrate. The relative position tolerance can be set small. Thereby, the fall of the relative positional accuracy of a heat sink, a terminal board, and a heat generating body can be suppressed. As a result, in the manufactured semiconductor device, it is possible to suppress the generation of cracks in the heating element and the bonding agent such as solder for fixing the heating element to the terminal board, and it is possible to suppress the deterioration of the quality of the semiconductor device.
Further, in the semiconductor device manufactured by the lead frame having the above-described configuration, since the engaging portion is formed on the connecting plate, the heat sink and the mold resin can be firmly fixed by the connecting plate. That is, the adhesion between the heat sink and the mold resin can be improved.

In particular, since the connecting plate for improving the adhesion between the heat sink and the mold resin is fixed to the upper surface of the heat sink, in the manufactured semiconductor device, it is sufficient that the mold resin only seals the upper surface of the heat sink. Adhesion can be obtained. Therefore, when the size of the semiconductor device itself is not changed, the heat sink is increased in size by increasing the heat capacity by the volume of the mold resin that covers the side surface of the heat sink as in the past, and the heat dissipation performance of the semiconductor device Improvement can also be achieved.
In addition, since it is not necessary to form a complicated shape for engaging with the mold resin on the heat sink itself as in the prior art, the semiconductor device can be manufactured at low cost.

In the lead frame, the engaging portion may be a widened portion that is formed in a middle portion of the connecting plate protruding in the thickness direction and wider than the other portions.
In this configuration, since the mold resin enters between the upper surface of the heat sink and the widened portion when manufacturing the semiconductor device, it is possible to reliably prevent the mold resin from being caught by the widened portion and being peeled off from the upper surface of the heat sink.
In addition, since the lead frame including the connecting plate is made of a conductive material having excellent thermal conductivity, heat released from the semiconductor element or the like to the heat sink can be further released from the heat sink to the connecting plate. Since the heat capacity of the connecting plate can be increased by having the widened portion, the heat of the heat sink can be efficiently released to the connecting plate.

Further, in the lead frame, the widened portion may have a tapered portion that gradually becomes wider from the proximal end side to the distal end side of the connecting plate.
In this configuration, since the side closer to the heat sink in the widened portion is set to be particularly wide, the heat capacity in the portion closer to the heat sink in the connecting plate can be particularly increased. That is, the heat released from the semiconductor element or the like to the heat sink can be more efficiently released from the heat sink to the connecting plate side.

Furthermore, in the lead frame, the side end of the tapered portion may be formed in an arc shape that bulges outward.
In this configuration, since the volume of the widened portion can be set larger as much as the side end of the tapered portion bulges, the heat capacity of the connecting plate can be further increased.

In the lead frame, it is preferable that the engaging portion is a reverse tapered portion that gradually becomes wider from the distal end side to the proximal end side of the connecting plate.
In a semiconductor device manufactured using this lead frame, the reverse taper portion of the connecting plate is arranged so as to become wider as it moves away from the upper surface of the heat sink, so this reverse taper portion is embedded in the mold resin. In this state, it is possible to reliably prevent the mold resin from being caught on the reverse taper portion and peeled off from the upper surface of the heat sink.
In addition, the reverse tapered portion is also formed with a part of the connecting plate so that the heat capacity of the connecting plate is increased, and the heat of the heat sink is efficiently converted into the connecting plate, as in the case of the widened portion described above. I can escape.

In the lead frame, the engaging portion is preferably a corrugated plate portion that is formed in the connecting plate and undulates in the thickness direction of the connecting plate so as to extend in the thickness direction.
In this configuration, since the concavo-convex surface is formed on the connecting plate by the corrugated plate portion, the mold resin meshes with the concavo-convex surface in the state of the semiconductor device. In particular, since this uneven surface undulates in a direction away from the upper surface of the heat sink, it is possible to reliably prevent the mold resin from peeling off from the upper surface of the heat sink.

Furthermore, in the lead frame, it is preferable that the engaging portion has a meandering portion that extends while meandering from a proximal end side to a distal end side of the connecting plate.
In this configuration, since the meandering portion is embedded in the mold resin, it is possible to reliably prevent the mold resin from being caught by the meandering portion and peeled off from the upper surface of the heat sink. Even if only a part of the meandering part on the tip side of the connecting plate is embedded in the mold resin, a part of the meandering part can be engaged with the mold resin.

Further, in the lead frame, the arrangement portion may be arranged so as to be shifted in a protruding direction of the connecting plate with respect to the frame body portion.
In this configuration, since the distance between the placement portion and the upper surface of the heat sink can be set short, the heat generated in the heating element can be efficiently released from the placement portion to the heat sink. That is, the heat dissipation of the semiconductor device can be further improved.

Furthermore, in the lead frame, it is preferable that a plurality of the connecting plates are formed, and the plurality of connecting plates are arranged symmetrically with respect to the center of the heat sink in plan view.
In this configuration, when manufacturing the semiconductor device, the lead frame can be fixed to the upper surface of the heat sink in a stable state.

  And, in the semiconductor device of the present invention manufactured using the lead frame, the heating element is fixed to the upper surface of the arrangement portion, and the terminal plate is arranged on the upper surface of the heat sink with a space therebetween, In addition, the upper surface of the heat sink, the terminal plate, the connection plate, and the heating element are sealed with the mold resin in a state where the connection plate is erected and fixed on the upper surface of the heat sink, and the lower surface of the heat sink And the side surfaces are exposed to the outside.

In this semiconductor device, as described above, since the connecting plate for improving the adhesion between the heat sink and the mold resin is fixed to the upper surface of the heat sink, even if only the upper surface of the heat sink is sealed with the mold resin, Adhesiveness with the mold resin can be sufficiently obtained.
If the size of the semiconductor device is not changed, the heat sink is formed larger to increase the heat capacity by the volume of the mold resin that covered the side surface of the heat sink as in the past, improving the heat dissipation performance of the semiconductor device. Can also be planned.

Furthermore, in the semiconductor device, it is preferable that the mold resin is filled between an upper surface of the heat sink and a lower surface of the arrangement portion.
In this configuration, even if the heat sink has conductivity like the terminal plate, the heat insulation and the terminal plate can be electrically insulated by the mold resin.
Since a separate member for electrically insulating the heat sink and the terminal board is not necessary, it is possible to improve the manufacturing efficiency of the semiconductor device and reduce the manufacturing cost.

According to the present invention, since the deterioration of the relative positional accuracy of the heat sink, the terminal plate, and the heating element can be suppressed during the manufacture of the semiconductor device, the heating element and this are fixed to the terminal plate in the manufactured semiconductor device. Therefore, it is possible to suppress the occurrence of cracks in the bonding agent such as solder to suppress deterioration in the quality of the semiconductor device.
Further, in the semiconductor device, since the heat sink and the mold resin are firmly fixed by the engaging portion of the connecting plate, the adhesion between the heat sink and the mold resin can be improved.

Furthermore, even if the mold resin seals only the upper surface of the heat sink, the improvement in the adhesion between the heat sink and the mold resin can be achieved. It is also possible to improve the heat dissipation performance of the semiconductor device.
Further, as the adhesion between the heat sink and the mold resin is improved, the heat sink can be formed in a simple shape, and the manufacturing cost of the semiconductor device can be reduced.

It is a perspective view which shows the state which attached the heat sink to the lead frame which concerns on 1st embodiment of this invention. FIG. 2 is a schematic top view showing the lead frame and heat sink of FIG. 1. It is AA arrow sectional drawing of FIG. It is a schematic top view which shows the semiconductor device manufactured using the lead frame of FIGS. It is a BB arrow sectional view of Drawing 4. It is a lead frame which concerns on 2nd embodiment of this invention, (a) is a perspective view, (b) is a principal part enlarged plan view which shows the level | step-difference part of a connection board. It is a lead frame which concerns on 3rd embodiment of this invention, (a) is a perspective view, (b) is a principal part enlarged plan view which shows the level | step-difference part of a connection board. It is a lead frame which concerns on 4th embodiment of this invention, (a) is a perspective view, (b) is a principal part enlarged plan view which shows the level | step-difference part of a connection board. It is a lead frame which concerns on 5th embodiment of this invention, (a) is a perspective view, (b) is a principal part enlarged plan view which shows the level | step-difference part of a connection board. It is a lead frame which concerns on 6th embodiment of this invention, (a) is a perspective view, (b) is a principal part expansion perspective view which shows the level | step-difference part of a connection board. It is a perspective view which shows the lead frame which concerns on 7th embodiment of this invention. FIG. 12 is a schematic top view showing a state after a resin sealing step in a manufacturing process of a semiconductor device using the lead frame of FIG. 11.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 3, the lead frame 1 according to this embodiment includes a heat sink 6, a plurality of terminal plates 2, 3, a semiconductor element (heating element) 7, and a connector 8 sealed with a mold resin 9. A plurality of (four in the illustrated example) terminal plates 2, 3 and a plurality (two in the illustrated example) of connecting plates 4, The terminal plate 2, 3 and the connecting plate 4 are integrally configured to have a plate-like frame portion 5 that connects the connecting plate 4 together. The lead frame 1 can be obtained by subjecting a conductive plate material such as a copper plate to press processing or etching processing.
In the illustrated lead frame 1, only the units of the terminal plates 2 and 3 and the connecting plate 4 required for manufacturing one semiconductor device 100 are formed. For example, a plurality of units are provided via the frame body portion 5. May be formed continuously. That is, the lead frame 1 may be configured so that a plurality of semiconductor devices 100 can be manufactured simultaneously.
The frame body portion 5 includes an outer frame portion 51 having a rectangular inner edge in plan view, and a plurality of tie bars 52 that connect the inner edge of the outer frame portion 51 to the terminal plates 2 and 3 and the connecting plate 4. ing.

Each of the terminal plates 2 and 3 is formed so as to protrude inward from the inner edge of the outer frame portion 51 in a plan view, and exhibits a crank shape in a cross-sectional view by bending in the middle portion in the longitudinal direction. Yes.
That is, the terminal plates 2 and 3 are arranged at the same height position as the frame body portion 5 and connected to the tie bar 52 with the flat base end plate portions 21 and 31 and the base end plate portions 21 and 31. On the other hand, flat distal plate portions 22 and 32 that are positioned lower in the thickness direction of the frame body portion 5, and proximal end plate portions 21 and 31 and the distal plate portion 22 that extend in the thickness direction of the frame body portion 5. , 32 are integrally formed with flat stepped plate portions 23, 33 for connecting the two. In the illustrated example, the surface directions of the base end plate portions 21 and 31 and the front end plate portions 22 and 32 are parallel to each other.

The plurality of terminal plates 2 and 3 protrude in opposite directions so that the pair of terminal plates 2 and 3 approach each other, and the front end plate portions 22 and 32 of the pair of terminal plates 2 and 3 are adjacent to each other with a space therebetween. It is arranged. And the front-end | tip board part 22 which comprises one (1st terminal board 2) of a pair of terminal boards 2 and 3 is the terminal board 2 rather than the front-end | tip board part 32 of the other terminal board (2nd terminal board 3). , 3 is formed long in the projecting direction, and constitutes an arrangement portion on which the semiconductor element 7 is mounted. The surface of the tip plate portion 22 on which the semiconductor element 7 is mounted is an upper surface 22a that faces the frame body portion 5 side.
The first terminal plate 2 and the second terminal plate 3 are each formed in a plurality (two in the illustrated example), and are arranged at intervals in the width direction of the terminal plates 2 and 3. The first terminal plate 2 and the second terminal plate 3 are arranged in parallel to each other.
The plurality of terminal plates 2 and 3 arranged as described above are connected to the outer frame portion 51 by connecting tie bars 52 to both side ends of the respective base end plate portions 21 and 31.

The connecting plate 4 is for fixing the lead frame 1 to the heat sink 6 when the semiconductor device 100 is manufactured, and protrudes in the thickness direction with respect to the frame body portion 5.
More specifically, like the terminal plates 2 and 3 described above, the connecting plate 4 is formed in a band shape protruding from the tie bar 52 toward the inside of the inner edge of the outer frame portion 51 in the plan view, and its longitudinal direction. A crank shape in a cross-sectional view is obtained by bending the middle part. That is, the connecting plate 4 is connected to the tie bar 52 and is located at the same height as the frame body part 5, and is lower than the base end part 41 in the thickness direction of the frame body part 5. A distal end portion (front end) 42 that is positioned and a stepped portion 43 that extends in the thickness direction of the frame body portion 5 and connects the base end portion 41 and the distal end portion 42 to each other are integrally formed. Therefore, in the connecting plate 4, bent portions 44 and 45 are formed between the base end portion 41 and the stepped portion 43 and between the stepped portion 43 and the tip end portion 42 by bending. Yes. In the illustrated example, the surface directions of the proximal end portion 41 and the distal end portion 42 are parallel to each other.
And the front-end | tip part 42 of the connecting plate 4 is located below the lower surfaces 22b and 32b of the front-end plate parts 22 and 32 which comprise the terminal plates 2 and 3, and is located in the lower surface 22b of the front-end plate parts 22 and 32. , 32b, the lower surface 42b of the tip 42 facing in the same direction is a surface to be fixed to the heat sink 6.

A plurality (two in the illustrated example) of the connecting plates 4 configured as described above are formed, and each of the connecting plates 4 protrudes from the tie bar 52 in the same direction as the first terminal plate 2 or the second terminal plate 3 in plan view. The one terminal plate 2 and the second terminal plate 3 are arranged at an interval in the width direction.
Further, the plurality of connecting plates 4 are arranged at positions that are symmetric with respect to the center of the heat sink 6 in plan view. More specifically, for example, as shown in FIG. 2, the first terminal plate 2 and one connecting plate 4 </ b> A arranged at intervals in the width direction are arranged in the arrangement direction of the plurality of first terminal plates 2. The other connecting plate 4 </ b> B only needs to be positioned at the other end in the arrangement direction of the plurality of second terminal plates 3. In this case, the two connecting plates 4A and 4B do not oppose the protruding direction of the connecting plate 4 in plan view. Further, for example, when one connecting plate 4 </ b> A is positioned between the two first terminal plates 2, the other connecting plate 4 </ b> B may be positioned between the two second terminal plates 3. In this case, the two connecting plates 4A and 4B are opposed to the protruding direction of the connecting plate 4 in plan view.

Next, an example of a method for manufacturing the semiconductor device 100 using the lead frame 1 will be described.
When manufacturing the semiconductor device 100, first, the lead frame 1 having the above-described configuration is prepared (frame preparation step). Next, the lower surfaces 42b of the front end portions 42 of the plurality of connecting plates 4 are bonded and fixed to the upper surface 6a of the heat sink 6 formed in a plate shape via a bonding agent such as solder (attachment process). In this step, each connecting plate 4 is fixed to the heat sink 6 so that the plurality of connecting plates 4 are symmetrical with each other with respect to the center of the heat sink 6 in plan view.
In this fixed state, the heat sink 6 and the plurality of terminal plates 2 and 3 are integrally fixed via the connecting plate 4 and the frame body portion 5 of the lead frame 1. That is, the heat sink 6 and the plurality of terminal boards 2 and 3 are relatively positioned. Further, in this state, a gap is defined between the lower surfaces 22 b and 32 b of the tip plate portions 22 and 32 of the terminal plates 2 and 3 and the upper surface 6 a of the heat sink 6.
The heat sink 6 serves to efficiently dissipate heat generated in the semiconductor element 7. The heat sink 6 may be made of at least a material having high heat dissipation such as copper (Cu), tungsten, molybdenum or the like, but may be Ni plated, for example.

Next, as shown in FIGS. 4 and 5, the plate-like semiconductor elements 7 are respectively fixed to the upper surface 22 a of the tip plate portion 22 constituting each first terminal plate 2 (mounting process). Here, the semiconductor element 7 has electrodes on the upper surface 7a and the lower surface 7b, and generates heat when energized like a diode. For this reason, in this mounting process, the semiconductor element 7 is joined to the upper surface of the tip plate portion by bonding the lower surface of the semiconductor element 7 to the upper surface of the tip plate portion through a conductive bonding agent such as solder. 2 to be electrically connected.
After this mounting step, both ends of the connector 8 formed in the shape of a strip having conductivity are connected to the top end of the upper surface 7a of the semiconductor element 7 and the second terminal plate 3 through a conductive bonding agent such as solder. It joins to the upper surface 32a of the board part 32 (connection process). As a result, the semiconductor element 7 and the second terminal plate 3 are electrically connected.

Thereafter, the upper surface 6a of the heat sink 6, the tip plate portions 22 and 32 and the step plate portions 23 and 33 of the plurality of terminal plates 2 and 3, the tip portion 42 and the step portion 43 of the plurality of connecting plates 4, the semiconductor element 7, and The connector 8 is sealed with the mold resin 9 (resin sealing step). In this state, the mold resin 9 is also filled between the heat sink 6 and the end plate portions 22 and 32 of the terminal plates 2 and 3. Further, the bent portion 44 between the base end portion 41 and the stepped portion 43 forming the connecting plate 4 is also sealed.
On the other hand, the frame body portion 5, the base end plate portions 21 and 31 of the plurality of terminal plates 2 and 3, and the base end portions 41 of the plurality of connecting plates 4 are located outside the mold resin 9 (see FIG. 2). . Further, the lower surface 6 b and the side surface 6 c of the heat sink 6 are exposed to the outside without being sealed by the mold resin 9.

  Finally, the frame body 5 is cut off from the terminal plates 2 and 3 and the connecting plate 4 (cutting process), whereby the manufacture of the semiconductor device 100 is completed. By carrying out this cutting step, the plurality of terminal plates 2 and 3 and the connecting plate 4 are electrically separated from each other. In the present embodiment, a part of the base end portion 41 of each connection plate 4 is also cut off together with the frame body portion 5 in the cutting step so that each connection plate 4 does not protrude from the mold resin 9.

  In the semiconductor device 100 manufactured as described above, the end plate portions 22 and 32 of the terminal plates 2 and 3 are electrically connected to the semiconductor element 7 directly or via the connector 8, that is, the semiconductor element. 7 functions as an internal terminal for electrical connection. On the other hand, the base end plate portions 21 and 31 of the terminal plates 2 and 3 project outside the mold resin 9 and function as external terminals for electrically connecting the semiconductor element 7 to the outside. In other words, the terminal plates 2 and 3 and the connector 8 function as electrical wiring for drawing out the electrode of the semiconductor element 7 to the outside of the mold resin 9.

Further, since the mold resin 9 is interposed between the heat sink 6 and the end plate portions 22 and 32 of the terminal plates 2 and 3, the heat sink 6 and the terminal plates 2 and 3 are electrically insulated from each other. Has been. Further, the tip plate portions 22 and 32 and the step plate portions 23 and 33 of the plurality of terminal plates 2 and 3 embedded in the mold resin 9 are formed by the mold resin 9 interposed between the plurality of terminal plates 2 and 3. They are electrically isolated from each other.
In the semiconductor device 100, heat generated in the semiconductor element 7 by energization is radiated mainly through the first terminal plate 2, the mold resin 9, and the heat sink 6.

  As described above, according to the lead frame 1 of the present embodiment and the semiconductor device 100 manufactured thereby, the semiconductor device is compared with the conventional configuration in which the heat sink and the terminal plate are fixed via the insulating substrate. Since the heat sink 6 and the plurality of terminal plates 2 and 3 can be directly fixed at the time of manufacturing 100, the tolerance of the relative position between the heat sink 6 and the plurality of terminal plates 2 and 3 can be set small. Thereby, the fall of the relative positional accuracy of the heat sink 6, the terminal boards 2 and 3, and the semiconductor element 7 can be suppressed. As a result, in the manufactured semiconductor device 100, it is possible to suppress the occurrence of cracks in the semiconductor element 7 and a bonding agent such as solder for fixing the semiconductor element 7 to the first terminal plate 2, thereby reducing the quality of the semiconductor device 100. Can be suppressed.

In the semiconductor device 100 of the present embodiment, not only the distal end portion 42 and the stepped portion 43 of the connecting plate 4 but also the bent portion 44 between the base end portion 41 and the stepped portion 43 is embedded in the mold resin 9. Therefore, the mold resin 9 can be reliably prevented from being pulled off from the upper surface 6 a of the heat sink 6 by being caught by the bent portion 44. In other words, the heat sink 6 and the mold resin 9 can be firmly fixed by the connecting plate 4 because the bent portion 44 forms an engaging portion for engaging with the mold resin 9. That is, the adhesion between the heat sink 6 and the mold resin 9 can be improved.
Further, since it is not necessary to form a complicated shape for engaging the heat sink 6 with the mold resin 9 as in the prior art, the semiconductor device 100 can be manufactured at low cost.

Further, in the semiconductor device 100 of the present embodiment, as described above, since the mold resin 9 seals only the upper surface 6a of the heat sink 6, sufficient adhesion between the heat sink 6 and the mold resin 9 can be obtained. If the size of the device 100 itself is not changed, the heat capacity can be increased by forming the heat sink 6 larger by the volume of the mold resin 9 that has covered the side surface 6c of the heat sink 6 as in the prior art.
Furthermore, the distal end plate portion 22 of the first terminal plate 2 on which the semiconductor element 7 is mounted is arranged so as to be shifted in the same direction as the connecting plate 4 with respect to the proximal end plate portion 21 and the frame body portion 5. The distance between the tip plate portion 22 and the upper surface 6a of the heat sink 6 can be set short. Therefore, the heat generated in the semiconductor element 7 can be efficiently released from the tip plate portion 22 to the heat sink 6.
In this semiconductor device 100, since the lead frame 1 including the connecting plate 4 is made of a conductive material having excellent heat conductivity, the heat generated in the semiconductor element 7 is not only connected to the heat sink 6, but also connected to the heat sink 6. The plate 4 can also escape. In other words, the substantial heat capacity of the heat sink 6 can be further increased by the connecting plate 4.
From the above, in the semiconductor device 100 of this embodiment, the heat dissipation performance can be improved.

Furthermore, since the plurality of connecting plates 4 are arranged at positions symmetrical to each other with respect to the center of the heat sink 6 in plan view, a resin sealing step is performed particularly after the mounting step when the semiconductor device 100 is manufactured. In the meantime, since the lead frame can be stably held on the upper surface of the heat sink, a unit in which the lead frame is fixed to the heat sink can be easily handled.
Further, in the semiconductor device 100 of the present embodiment, the heat sink 6 and the terminal plates 2 and 3 are conventionally insulated because they are electrically insulated from each other by the mold resin 9 interposed between the heat sink 6 and the terminal plates 2 and 3. There is no need for a separate member for electrical insulation. Therefore, it is possible to improve the manufacturing efficiency of the semiconductor device 100 and reduce the manufacturing cost.

  In the first embodiment, the bent portion 44 between the base end portion 41 and the stepped portion 43 sealed by the mold resin 9 is engaged with the mold resin 9, but the bent portion 44 is sealed. The step part 43 of the connecting plate 4 arranged so as to protrude at least from the upper surface 6 a of the heat sink 6 may be sealed with the mold resin 9. Even in such a configuration, the anchor portion is obtained by the stepped portion 43 of the connecting plate 4 being pierced into the mold resin 9, so that the adhesion between the heat sink 6 and the mold resin 9 can be improved. In other words, the stepped portion 43 of the connecting plate 4 may serve as an engaging portion that engages with the mold resin 9.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 6, the lead frame according to this embodiment is different from the lead frame 1 of the first embodiment only in the shape of the connecting plate 4.
In the lead frame 11 of this embodiment, a middle portion of the connecting plate 4 in the protruding direction among the stepped portions 43 protruding in the thickness direction of the frame body portion 5 from the proximal end portion 41 side toward the distal end portion 42 side. In addition, a widened portion (engagement portion) 46 that is wider than other portions of the connecting plate 4 is formed. Here, the other portions of the connecting plate 4 indicate both ends of the stepped portion 43 in the protruding direction, the base end portion 41, and the tip end portion 42.
In the illustrated example, the widened portion 46 is formed in a rectangular shape in plan view, but may be formed in a circular shape in plan view, for example. Moreover, although the wide part 46 is formed so that it may protrude from the both ends of the connection board 4, it may be formed, for example so that it may protrude only from one side end.

According to the lead frame 11 of the present embodiment, the same effects as in the first embodiment can be obtained.
Further, when a semiconductor device similar to that of the first embodiment is manufactured using the lead frame 11, the mold resin 9 enters between the upper surface 6 a of the heat sink 6 and the widened portion 46, so that the mold resin 9 enters the widened portion 46. It is possible to reliably prevent the hooked heat sink 6 from peeling off from the upper surface 6a.
Furthermore, in the manufactured semiconductor device, the portion of the connecting plate 4 embedded in the mold resin 9 has the widened portion 46 so that the heat capacity of the connecting plate 4 can be increased. It is possible to escape.

[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 7, the lead frame according to the present embodiment is different from the lead frame 11 of the second embodiment only in the shape of the widened portion.
In the lead frame 12 of this embodiment, the widened portion 46 formed in the midway portion of the stepped portion 43 in the protruding direction is from the base end portion (base end) 41 side of the connecting plate 4 toward the tip end portion 42 side. The taper portion 461 is gradually widened. In this embodiment, both side ends of the taper portion 461 are inclined in a straight line, so that the taper portion 461 has a substantially trapezoidal shape in plan view.

According to the lead frame 12 of the present embodiment, the same effects as those of the second embodiment are achieved.
Moreover, in this structure, since the side close to the heat sink 6 in the widened portion 46 is set to be particularly wide, the heat capacity in the portion closer to the heat sink 6 in the connecting plate 4 can be particularly increased. That is, the heat released from the semiconductor element 7 or the like to the heat sink 6 can be more efficiently released from the heat sink 6 to the connecting plate 4 side.

[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 8, the lead frame according to this embodiment differs from the lead frame 12 according to the third embodiment only in the shape of the tapered portion formed in the stepped portion 43 of the connecting plate 4. That is, in the lead frame 13 of this embodiment, both side ends of the tapered portion 462 forming the widened portion 46 are formed in an arc shape that bulges outward, whereby the tapered portion 462 is substantially semicircular in plan view. It has a shape.

According to the lead frame 13 of the present embodiment, the same effect as that of the third embodiment can be obtained. However, since the volume of the widened portion 46 can be set larger by the extent that both side ends of the tapered portion 462 bulge, the connecting plate 4 The heat capacity of can be further increased.
In the third and fourth embodiments, the taper portions 461 and 462 are formed over the entire longitudinal direction of the widened portion 46 along the protruding direction of the stepped portion 43. For example, a part of the widened portion 46 in the longitudinal direction is formed. It may be formed only on.

[Fifth embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 9, the lead frame according to this embodiment differs from the lead frames according to the first to fourth embodiments in the shape of the connecting plate 4.
In the lead frame 14 of this embodiment, the stepped portion 43 of the connecting plate 4 has a reverse taper portion (engaging portion) 47 that gradually becomes wider from the distal end portion 42 side to the proximal end portion 41 side of the connecting plate 4. Is formed. In this embodiment, both side ends of the reverse taper portion 47 are inclined linearly, whereby the reverse taper portion 47 has a substantially trapezoidal shape in plan view. In the illustrated example, the reverse tapered portion 47 is formed without a gap between the tip portion 42, but, for example, like the widened portion 46 of the second embodiment, the gap between the tip portion 42 is provided. It may be formed with a gap.

According to the lead frame 14 of the present embodiment, the same effects as those of the second embodiment can be obtained. That is, when a semiconductor device similar to that of the first embodiment is manufactured using the lead frame 14, the reverse taper portion 47 is arranged so as to become wider as it moves away from the upper surface 6a of the heat sink 6. In a state where the taper portion 47 is embedded in the mold resin 9, it is possible to reliably prevent the mold resin 9 from being caught by the reverse taper portion 47 and peeled off from the upper surface 6 a of the heat sink 6.
Further, in the semiconductor device after manufacture, as in the case of the widened portion 46 of the second embodiment, a part of the connecting plate 4 is formed wide so that the heat capacity of the connecting plate 4 is increased, and the heat sink 6 Heat can be efficiently released to the connecting plate 4.

[Sixth embodiment]
Next, a sixth embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 10, the lead frame according to this embodiment is different in the shape of the connecting plate 4 from the lead frames of the first to fifth embodiments. That is, in the lead frame 15 of this embodiment, a corrugated plate portion (engaging portion) 48 that corrugates in the thickness direction of the connecting plate 4 is formed in the stepped portion 43 of the connecting plate 4 so as to extend in the protruding direction. .
According to the lead frame 15 of the present embodiment, the corrugated plate portion 48 has the uneven portions 48 a and 48 b formed on the step portion 43, so that the mold resin 9 is in a state where the step portion 43 is embedded in the mold resin 9. The uneven surfaces 48a and 48b are engaged with each other. In particular, since the concavo-convex surfaces 48 a and 48 b undulate so as to extend upward from the upper surface 6 a of the heat sink 6, it is possible to reliably prevent the mold resin 9 from being peeled off from the upper surface 6 a of the heat sink 6.

In the sixth embodiment, the corrugated plate portion 48 is formed in the stepped portion 43. However, it is sufficient that at least the stepped portion 43 has corrugated surfaces 48a and 48b that extend in the protruding direction. Therefore, the stepped portion 43 may be formed with, for example, a recess that is recessed in the thickness direction. As in the case of the corrugated plate portion 48, the concave portion may extend in the width direction of the stepped portion 43 so as to reach the side end of the stepped portion 43, but does not reach the side end of the stepped portion 43. Also good. Further, only one concave portion may be formed, but a plurality of concave portions may be arranged at intervals in the protruding direction of the stepped portion 43 as in the case of the corrugated plate portion 48.
Further, the corrugated plate portion 48 of the sixth embodiment is not limited to being formed on the stepped portion 43 having a simple band plate shape as in the first embodiment, and for example, the widening of the second to fifth embodiments. It may be formed in the stepped portion 43 having the portion 46, the tapered portions 461, 462, and the reverse tapered portion 47.

[Seventh embodiment]
Next, a seventh embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 11, the lead frame according to this embodiment is different in the shape of the connecting plate 4 from the lead frames of the first to sixth embodiments.
In the lead frame 16 of this embodiment, the stepped portion 43 of the coupling plate 4 meanders in the width direction of the proximal end portion 41 and the distal end portion 42 from the proximal end portion 41 side to the distal end portion 42 side of the coupling plate 4. A meandering portion (engaging portion) 49 extending while being formed is formed.
In this embodiment, the meandering portion 49 meanders in a crank shape in plan view, so that the proximal end portion 41 and the distal end portion 42 of the connecting plate 4 are mutually connected by the meandering portion 49 to the proximal end portion 41 and the distal end portion. The portion 42 is shifted in the width direction. Further, the distal end portion 42 of the connecting plate 4 is disposed closer to the terminal plates 2 and 3 than the proximal end portion 41.

When manufacturing the same semiconductor device as that of the first embodiment using this lead frame 16, in the resin sealing step, the entire stepped portion 43 including the meandering portion 49 is molded resin as in the first to sixth embodiments. For example, as shown in FIG. 12, only a part of the distal end portion 42 and the meandering portion 49 on the distal end portion 42 side is embedded in the mold resin 9, and the remaining portion of the meandering portion 49 and The base end portion 41 can be disposed outside the mold resin 9. In other words, a portion of the meandering portion 49 that extends in the width direction of the base end portion 41 and the tip end portion 42 (arrangement direction of the plurality of first terminal plates 2 or the second terminal plates 3) protrudes from the outer surface of the mold resin 9. Thus, the meandering portion 49 can be sealed with the mold resin 9.
When the meandering portion 49 is sealed as described above, the remaining portion of the meandering portion 49 protruding to the outside of the mold resin 9 and the base end portion 41 may be cut off in the cutting step of cutting off the frame body portion 5.

And in the semiconductor device manufactured in this way, since the mold resin 9 is caught by the meandering part 49 embedded in the inside, it can prevent reliably peeling from the upper surface 6a of the heat sink 6. FIG. Further, since the base end plate portions 21 and 31 of the terminal plates 2 and 3 and the meandering portion 49 of the connecting plate 4 protrude or are exposed in different directions from the outer surface of the mold resin 9, the terminal plates 2 and 3 It is possible to more reliably prevent an electrical short circuit from occurring between the base end plate portions 21 and 31 and the meandering portion 49 of the connecting plate 4.
In the seventh embodiment, the meandering portion 49 meanders in a crank shape in plan view, but may meander in, for example, an S shape in plan view. Moreover, although the base end part 41 and the front-end | tip part 42 of the connection board 4 were shifted and located in the width direction by the meander part 49, it does not need to be shifted in the width direction, for example. In this case, the entire meandering portion 49 may be embedded in the mold resin 9.

The details of the present invention have been described above with reference to the first to seventh embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Is possible.
For example, in all the embodiments, the front end portion 42 of the connecting plate 4 is located below the lower surfaces 22b and 32b of the front end plate portions 22 and 32 constituting the terminal plates 2 and 3, but at least connected. The lower surface 42b of the front end portion 42 of the plate 4 only needs to be positioned below the lower surfaces 22b, 32b of the front end plate portions 22, 32 of the terminal plates 2, 3. Even in this case, a gap is provided between the lower surfaces 22b and 32b of the tip plate portions 22 and 32 and the upper surface 6a of the heat sink 6 in a state where the lower surface 42b of the tip portion 42 of the connecting plate 4 is fixed to the upper surface 6a of the heat sink 6. It is possible.

In all the embodiments, the lead frames 1, 11 to 16 are used for manufacturing the semiconductor device 100 having a configuration in which the mold resin 9 is interposed between the upper surface 6 a of the heat sink 6 and the terminal plates 2, 3. However, it may be used for manufacturing a semiconductor device having a configuration in which an insulating plate material having electrical insulating properties such as ceramics is provided between the heat sink 6 and the terminal plates 2 and 3. The insulating plate material may be sandwiched between the heat sink 6 and the end plate portions 22 and 32 of the terminal plates 2 and 3 in the mounting process, for example.
Furthermore, when manufacturing the semiconductor device 100, the attachment process of attaching the lead frames 1, 11 to 16 to the upper surface 6a of the heat sink 6 is performed before the mounting process and the connection process, but at least after the frame preparation process. What is necessary is just to implement before the resin sealing process.

Further, the semiconductor element 7 is not limited to having the electrodes on the upper surface 7a and the lower surface 7b, and may have a plurality of electrodes only on the upper surface 7a, for example. In this case, for example, a plurality of second terminal plates 3 are prepared for one semiconductor element 7, and a plurality of electrodes of the semiconductor element 7 and a plurality of second terminal plates 3 are connected via a plurality of connectors. What is necessary is just to make an electrical connection.
Furthermore, although the semiconductor device 100 of the above-described embodiment includes the semiconductor element 7 as a heating element, any other heating element can be used as long as it is fixed to the upper surface 22a of the distal end plate portion 22 of the first terminal board 2. The electronic parts / electric parts may be provided.

Further, in all the embodiments, the plurality of first terminal boards 2 are arranged so that the longitudinal directions from the base end plate portion 21 toward the front end plate portion 22 are all the same direction. Or you may arrange | position so that it may become reverse direction. The plurality of second terminal plates 3 may also be arranged so as to be in different directions or in opposite directions, for example, similarly to the first terminal plate 2. Therefore, for example, the longitudinal directions of the first terminal plate 2 and the second terminal plate 3 from the proximal end plate portions 21 and 31 toward the distal end plate portions 22 and 32 may be set in the same direction.
Further, although the terminal plates 2 and 3 are formed in a crank shape in a sectional view, they may be formed in a simple flat plate shape, for example.
In addition, the connector 8 that electrically connects the second terminal plate 3 and the semiconductor element 7 is formed in a plate shape, but may be a bonding wire, for example.

1,11,12,13,14,15,16 Lead frame 2 First terminal board 22 End plate part (arrangement part)
22a Upper surface 22b Lower surface 3 Second terminal plate 32 Tip plate portion 32b Lower surface 4, 4A, 4B Connecting plate 41 Base end (base end)
42 Tip (tip)
43 Step part (engagement part)
44 Bent part (engagement part)
46 Widening part (engagement part)
461, 462 Taper part 47 Reverse taper part (engagement part)
48 Corrugated plate part (engagement part)
49 Meandering part (engaging part)
5 Frame body part 6 Heat sink 6a Upper surface 6b Lower surface 6c Side surface 7 Semiconductor element (heating element)
9 Mold Resin 100 Semiconductor Device

Claims (11)

A plate-shaped heat sink, a terminal plate arranged on the upper surface of the heat sink with a space, and a heating element fixed to the upper surface of the plate-shaped arrangement portion of the terminal plate and electrically connected to the terminal plate; A lead frame used for manufacturing a semiconductor device comprising a mold resin for sealing the heat sink, the terminal plate and the heating element,
The terminal plate, a connection plate for fixing to the heat sink, and a plate-like frame body portion that integrally connects them,
By projecting the connecting plate in the thickness direction with respect to the frame body portion, the tip of the connecting plate is positioned below the lower surface of the arrangement portion,
The lead frame according to claim 1, wherein an engaging portion for engaging with the mold resin is formed on the connecting plate.   2. The lead frame according to claim 1, wherein the engaging portion is a widened portion that is formed in a middle portion of the connecting plate protruding in the thickness direction and is wider than other portions.   3. The lead frame according to claim 2, wherein the widened portion has a tapered portion that gradually increases in width from the proximal end side to the distal end side of the connecting plate.   The lead frame according to claim 3, wherein a side end of the tapered portion is formed in an arc shape that bulges outward.   2. The lead frame according to claim 1, wherein the engaging portion is a reverse tapered portion that gradually increases in width from the distal end side to the proximal end side of the connecting plate.   The lead frame according to claim 1, wherein the engaging portion is a corrugated plate portion that is formed in the connecting plate and extends in the thickness direction of the connecting plate so as to extend in the thickness direction.   2. The lead frame according to claim 1, wherein the engaging portion has a meandering portion extending while meandering from a proximal end side to a distal end side of the connecting plate.   The lead frame according to any one of claims 1 to 7, wherein the arrangement portion is arranged so as to be shifted in a protruding direction of the connecting plate with respect to the frame body portion. A plurality of the connecting plates are formed,
The lead frame according to any one of claims 1 to 8, wherein the plurality of connecting plates are arranged symmetrically with respect to a center of the heat sink in plan view. A semiconductor device manufactured using the lead frame according to any one of claims 1 to 9,
The heating element is fixed to the upper surface of the arrangement portion, the terminal plate is arranged on the upper surface of the heat sink with a space, and the connecting plate is fixed upright on the upper surface of the heat sink. In the state, the upper surface of the heat sink, the terminal plate, the connecting plate and the heating element are sealed with the mold resin,
A semiconductor device, wherein a lower surface and a side surface of the heat sink are exposed to the outside.   The semiconductor device according to claim 10, wherein the mold resin is filled between an upper surface of the heat sink and a lower surface of the arrangement portion.

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