Patent ID: 12255080

DESCRIPTION OF EMBODIMENTS

First Embodiment

A semiconductor device and a semiconductor manufacturing apparatus according to a first embodiment will be described.

(Semiconductor Device)

First of all, a semiconductor device manufactured by a semiconductor manufacturing apparatus will be described. As shown inFIG.1,FIG.2, andFIG.3, in a semiconductor device1as a power semiconductor device, power semiconductor elements21and IC elements29are mounted as semiconductor elements on a lead frame45. Lead frame45is sealed together with power semiconductor elements21and the like with a mold resin33as a sealing material.

Mold resin33has a first side portion33a, a second side portion33b, a third side portion33c, a fourth side portion33d, a first main surface33e, and a second main surface33f. First side portion33aand second side portion33bare opposed to each other at a distance from each other in the X-axis direction and each extend in the Y-axis direction. Third side portion33cand fourth side portion33dare opposed to each other at a distance from each other in the Y-axis direction and each extend in the X-axis direction. First main surface33eand second main surface33fare opposed to each other at a distance from each other in the Z-axis direction.

On a surface of mold resin33, a resin trace34is left as a result of injection of fluid resin serving as mold resin33into a mold die. First side portion33ahas a resin injection trace34aas a first sealing material trace. As will be described later, resin injection trace34ais a resin trace left at a position corresponding to a resin injection gate through which a mold resin (fluid resin) is injected.

Second side portion33bhas a resin reservoir trace34bas a second sealing material trace. As will be described later, resin reservoir trace34bis a resin trace left at a position corresponding to a resin reservoir gate. Here, resin reservoir trace34bis at a position opposed to resin injection trace34ain the X-axis direction in the second side portion. The area of resin reservoir trace34bis smaller than the area of resin injection trace34a.

FIG.1shows convex resin trace34protruding from a surface of mold resin33. Resin trace34may be concave resin trace34depressed from a surface of mold resin33, depending on how mold resin33is detached from the mold die. In this case, as shown inFIG.45, concave resin injection trace34ais left on first side portion33a. Concave resin reservoir trace34bis left on second side portion33b. Furthermore, as shown inFIG.46, for example, concave resin injection trace34amay be left on first side portion33a, and convex resin reservoir trace34bmay be left on second side portion33b. Convex resin injection trace34amay be left, and concave resin reservoir trace34bmay be left (not shown).

Lead frame45includes power lead terminals5, power leads3, lead step portions7, a large die pad9, small die pads15(15a,15b,15c), IC leads23, and IC lead terminals25. Small die pads15include three small die pads15a,15b, and15c. Large die pad9and the like on which power semiconductor elements21are mounted are arranged at a position lower than the position (height) in the Z-axis direction of power lead3. Large die pad9and the like are arranged on a side closer to first main surface33ein mold resin33relative to the position in the Z-axis direction of power lead3.

The distance from large die pad9to first main surface [11e]33eis defined as distance L1. The distance from large die pad9to second main surface33fis defined as distance L2. Distance L1is shorter than distance L2. More specifically, the thickness of a portion of mold resin33covering the side (first surface) opposite to the side on which power semiconductor element21is mounted in large die pad9is smaller than the thickness of a portion of mold resin33covering the side (second surface) on which power semiconductor element21is mounted in large die pad9. As will be described later, a mold die has a resin reservoir gate and a resin reservoir in order to prevent voids in a portion of mold resin33covering the first main surface of large die pad9.

For example, three power semiconductor elements21are mounted on large die pad9. Each of three power semiconductor elements21is bonded to large die pad9by conductive adhesive19. For example, one power semiconductor element21is mounted on each of small die pads15a,15b, and15c. One power semiconductor element21is bonded to each of small die pads15a,15b, and15cby conductive adhesive (not shown).

Power semiconductor element21is, for example, an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). For example, solder or silver paste is employed as conductive adhesive19.

Large die pad9is connected to power lead3through lead step portion7. Each of small die pads15a,15b, and15chas a bending portion13. Bending portion13has an X-direction component and a Y-direction component and extends obliquely.

It is preferable that the value of the X coordinate of a distal end17aof small die pad15ais greater than the value of the X coordinate of a terminal end11aof lead step portion7. It is preferable that the value of the X coordinate of a distal end17bof small die pad15bis greater than the value of the X coordinate of a terminal end11bof lead step portion7. It is preferable that the value of the X coordinate of a distal end17cof small die pad15cis greater than the value of the X coordinate of a terminal end11cof lead step portion7.

Because of bending portion13, even when the space to the side (the X-axis negative direction) of large die pad9is relatively narrow, one power semiconductor element21can be mounted on each of three small die pads15a,15b, and15cwhile three power semiconductor elements21are mounted on large die pad9. With this configuration, power semiconductor elements21can be arranged efficiently in a limited capacity of semiconductor device1, contributing to size reduction of semiconductor device1.

Each of small die pads15a,15b, and15cis connected to power lead3through bending portion13and lead step portion7of small die pad15. Power lead3is connected to power lead terminal5. Power lead terminal5protrudes outward from third side portion33cof mold resin33.

For example, two IC elements29are mounted on IC lead23. Each of two IC elements29is bonded to IC lead23by conductive adhesive27. IC lead23is connected to IC lead terminal25. IC lead terminal25protrudes outward from fourth side portion33dof mold resin33.

The corresponding power semiconductor element21and IC element29are electrically connected by wire31. The corresponding power semiconductor element21and power lead3are electrically connected by wire31. The corresponding IC element29and IC lead23are electrically connected by wire31.

Wire31is formed of metal such as gold, silver, copper, or aluminum. In this way, an electrical circuit is formed on lead frame45. The material or the thickness of wire31can be changed according to a portion to connect. The portion connected to wire31may be processed, for example, coated for increasing the bonding strength of wire31.

In semiconductor device1described above, the structure in which power lead terminal5and IC lead terminal25protrude from mold resin33has been illustrated by example. As shown inFIG.4, semiconductor device1may have a structure in which power lead terminal5and IC lead terminal25are exposed on a surface of mold resin33such that they do not protrude from mold resin33. In this case, in order to connect wire31, it is preferable that two steps including a lead step portion7aand a lead step portion7bare formed as lead step portion7connected to large die pad9.

As shown inFIG.5, in a case of semiconductor device1in which a relatively low voltage is applied to power lead terminal5, the position in the height direction of power lead terminal5may be the same position as the position in the height direction of large die pad9. A voltage applied to power lead terminal5is relatively low, for example, when the voltage is 24 V. In this case, the step of forming lead step portion7in the lead frame is not necessary, thereby contributing to reduction in production cost.

As will be described later, a mold die has a plurality of cavities into which mold resin is injected. In some mold dies, the cavities include, for example, a first cavity and a second cavity. The first cavity and the second cavity are connected through a runner. The mold resin injected into the first cavity is injected to the second cavity through the runner. Part of the mold resin injected into the second cavity flows through the resin reservoir gate to the resin reservoir.

A resin trace attributable to the resin injection gate and a resin trace attributable to the runner are left on a surface of the semiconductor device sealed with the mold resin injected to the first cavity. As shown inFIG.6, resin injection trace34ais left as resin trace34attributable to the resin injection gate. A runner trace34cis left as resin trace34attributable to the runner. The area of resin injection trace34aand the area of runner trace34care substantially the same.

A resin trace attributable to the runner and a resin trace attributable to the resin reservoir gate are left on a surface of the semiconductor device sealed with the mold resin injected to the second cavity. As shown inFIG.1, resin injection trace34ais left as resin trace34attributable to the runner trace. Resin reservoir trace34bis left as resin trace34attributable to the resin reservoir gate.

Since the mold resin is injected from the runner into the second cavity, runner trace34ccan be regarded as resin injection trace34a. The area of resin reservoir trace34bis smaller than the area of runner trace34c(resin injection trace34a). The mold die serving as a semiconductor manufacturing apparatus will now be described.

(Mold Die)

As shown inFIG.7andFIG.8, mold die51has an upper die53and a lower die55. Mold die51has a cavity52. Cavity52extends in the X-axis direction as a first direction. Cavity52includes, for example, a first cavity52aand a second cavity52b. As shown inFIG.7andFIG.9, mold die51has a resin injection gate59through which mold resin is injected into first cavity52a. Mold die51has a runner61communicatively connecting first cavity52aand second cavity52b. The mold resin injected into first cavity52ais also injected into second cavity52bthrough runner61.

As shown inFIG.7andFIG.10, mold die51has a resin reservoir63into which part of fluid resin serving as mold resin injected into second cavity52bflows. Mold die51has a resin reservoir gate65communicatively connecting second cavity52band resin reservoir63. As shown inFIG.8and the like, resin reservoir63and resin reservoir gate65are formed, fur example, in lower die53.

Resin reservoir63is arranged on the other side at a distance in the X-axis direction from one side on which resin injection gate59is arranged with cavity52interposed. Resin reservoir gate65includes an inclined portion67and a movable pin69serving as a shutter. Movable pin69is movable in the vertical direction (the Z-axis direction).

As shown inFIG.9andFIG.10, the opening cross-sectional area (for example, width LY2×height LZ2) as a second opening cross-sectional area at a portion where inclined portion67is located in resin reservoir gate65is set to be smaller than the opening cross-sectional area (for example, width LY1×height LZ1) as a first opening cross-sectional area of resin injection gate59.

In a state in which movable pin69is accommodated in lower die53, the distal end portion of movable pin69is at the same position as the surface of lower die53. Movable pin69can move in such a manner as to protrude in the height direction (the Z-axis direction) from the state in which it is accommodated in lower die53. It is required that wear of movable pin69moving in the Z-axis direction should be suppressed. Movable pin69is also required to have a function as a shutter to block the flow of mold resin. It is therefore preferable that the distal end of movable pin69in a protruding state is, for example, about 50 μm away from a frame37(lower surface).

FIG.10shows mold die51in such a manner that a gap corresponding to the thickness of frame37is formed between lower die53(upper surface53a) and the upper die (lower surface55a) in a state in which frame37in the lead frame is held between lower die53and upper die55. Mold die51is not limited to such a manner and, as shown inFIG.11, for example, mold die51may have a portion where lower die53(upper surface53a) and upper die55(lower surface55a) abut on each other.

The structure of resin reservoir gate65and the like will be described in more detail. As shown inFIG.10andFIG.12, inclined portion67is inclined so as to descend from a top portion67atoward resin reservoir63. The opening cross-sectional area (for example, LY3×LZ3) as a third opening cross-sectional area immediately before the flow into resin reservoir63in resin reservoir gate65is set to be larger than the opening cross-sectional area (for example, LY2×LZ2) of a portion where inclined portion67is located in resin reservoir gate65. As will be described later, the provision of inclined portion67facilitates release of the hardened mold resin from lower die53.

A portion66ahaving the second opening cross-sectional area (LY2×LZ2) corresponds to a first part of the sealing material reservoir gate. A portion66bhaving the third opening cross-sectional area (LY3×LZ3) corresponds to a second part of the sealing material reservoir gate.

In the step of sealing with mold resin, it is necessary that the mold resin (fluid resin) attempting to flow into resin reservoir63should not be left in resin reservoir63. In order to suppress wear or breakage of movable pin69, it is also necessary to reduce the distance by which movable pin69slides to upper die55. Specifically, the height LZ2(seeFIG.10) of a portion where inclined portion67is located is preferably, for example, about 300 to 500 μm. The height LZ3(seeFIG.10) of a portion of resin reservoir gate65immediately before the mold resin flows into resin reservoir63is preferably about twice the height LZ2, preferably, for example, about 600 to 1000 μm.

It is required that sliding friction of movable pin69against lower die53during movement in the vertical direction should be reduced. As shown inFIG.13, therefore, the cross-sectional shape (X-Y plane) of movable pin69is preferably, for example, circular or oval. The diameter D of movable pin69is preferably smaller than the width W in the Y direction of resin reservoir gate65, for example, by about 30 μm so that the flow of the mold resin is minimized when movable pin69protrudes to the height immediately before coming into abutment with the frame.

The distance L18from top portion67aof inclined portion67to the center of movable pin69in resin reservoir gate65is preferably as short as possible within a distance in which movable pin69does not overlap inclined portion67. When movable pin69is compared with the thrust valve described in PTL 1, movable pin69has a smaller diameter and is circular in cross section, whereby the sliding friction can be reduced, and movable pin69is less likely to be broken.

The width LY3(the Y direction) of resin reservoir gate65is preferably as small as possible, preferably equal to or smaller than half the width LY1(seeFIG.9) of resin injection gate59and the width of runner61. The width LY3of resin injection gate59is preferably, for example, about 0.5 to 1.5 mm since it is necessary to keep a cross section to some extent in order to release the mold resin flowing into resin reservoir63from lower die53. On the other hand, the width W of resin reservoir gate65is preferably 500 μm or more so that the mold resin flowing into resin reservoir63is not left in lower die53.

Compared with a structure according to a comparative example in which the width corresponding to the resin reservoir gate is the same as the width of the semiconductor device, the flow of the mold resin into resin reservoir63is suppressed, and cavity52can be reliably filled with the mold resin while the mold resin flowing into resin reservoir63is minimized. The capacity of resin reservoir63is adjusted by the length L11(the X-axis direction), the length L10(the Y-axis direction), and the length L12(the Z-axis direction).

In mold die51described above, resin reservoir gate65and resin reservoir63are formed in lower die53. As shown inFIG.14, resin reservoir gate65and resin reservoir63may be formed in upper die55of mold die51. In this case, movable pin69protrudes to a position immediately before coming into contact the frame from the state in which it is accommodated in upper die55.

(Method of Manufacturing Semiconductor Device)

A method of manufacturing a semiconductor device using the mold die described above will now be described. First, lead frame45(seeFIG.15) is formed by etching a metal plate or blanking a metal plate. Large die pad9, small die pads15, IC leads23, and the like are formed in lead frame45. Next, a bending die is used to bend lead frame50to form lead step portion7(seeFIG.15).

Power semiconductor element21is bonded to each of large die pad9and small die pads15by conductive adhesive (seeFIG.15). IC elements29are bonded to IC leads23by conductive adhesive (seeFIG.15). Next, wires31are connected. In this way, as shown inFIG.15, a plurality of semiconductor devices including lead frame45having power semiconductor elements21and the like mounted thereon before sealed with mold resin are formed. One semiconductor device (on the left side of lead frame45) and the other semiconductor device (on the right side of lead frame45) arranged in the X-axis direction are connected by a tie bar35.

Next, the semiconductor devices are sealed with mold resin by transfer molding. As shown inFIG.16, mold die51including upper die55and lower die53is prepared. Lead frame45(seeFIG.15) having power semiconductor elements21and the like mounted thereon is arranged between lower die53and upper die55. It is preferable that resin injection gate59is located on the side closer to large die pad9than to small die pad15in lead frame45.

The area of large die pad9is larger than the area of small die pad15. Because of this, a region between large die pad9and lower die53(the bottom surface of cavity52) is sometimes less filled with the mold resin. Then, resin injection gate59is arranged closer to large die pad9to ensure that the region between large die pad9and lower die53(the bottom surface of cavity52) is filled with fluid resin serving as mold resin with a low viscosity.

In addition, in order to efficiently fill the region with mold resin (fluid resin), it is preferable that the position (the Y-axis direction) of resin injection gate59and the position (the Y-axis direction) of runner61are closer to the center position (the Y-axis direction) of large die pad9. The position (the Y-axis direction) of resin injection gate59and the position (the Y-axis direction) of runner61are almost the same position.

Resin reservoir63and second cavity52bare connected through resin reservoir gate65. At this point of time, movable pin69is located above, and resin reservoir gate65is closed.

Next, a tablet resin81is loaded in a plunger57. After lower die53and upper die55are clamped, plunger57is elevated while tablet resin81is melted, whereby the melted fluid resin serving as mold resin is injected from resin injection gate59into cavity52(52a). The injected fluid resin fills the first cavity52aand then reaches runner61.

As shown inFIG.17, the fluid resin reaching runner61flows through runner61and is injected into second cavity52b. The distance from large die pad9and small die pads15to upper die55(the upper surface of second cavity52b) is longer than the distance from large die pad9and small die pads15to lower die53(the bottom surface of second cavity52b).

Fluid resin83therefore flows more easily to a region RC1of cavity52above large die pad9and small die pads15than to a region RC2of cavity52below large die pad9and small die pads15. Accordingly, fluid resin83flowing through region RC1finally flows from region RC1into region RC2and ultimately merges with fluid resin83flowing through region RC2at a position87(region85) below small die pad15(15C).

While cavity52is gradually filled with fluid resin83, the air in cavity52is discharged from air vents79provided in cavity52. As shown inFIG.18, air vents79are arranged on the periphery of cavity52. Air vents79are formed with, for example, depressions with a depth of about 100 μm provided in upper die55or lower die53. Air vents79will be described in more detail later.

As shown inFIG.19, when fluid resin83flowing through region RC1and fluid resin83flowing through region RC2merge at region85below small die pad15(15C), the air tends to be trapped in fluid resin83. Movable pin69is located above and resin reservoir gate65is closed until fluid resins83merge at region85(position87). When the trapped air is not collapsed, it may remain as voids in fluid resin83(mold resin).

Then, a process (step) of preventing voids from remaining in fluid resin83is performed. As shown inFIG.20andFIG.21, movable pin69descends to open resin reservoir gate65. With resin reservoir gate65opened, fluid resin83in second cavity52battempts to flow into resin reservoir63through resin reservoir gate65. InFIG.21, a portion of frame37is depicted by a dashed-two dotted line to show the structure of lower die53. In the following drawings, a portion of frame37is depicted by a dashed-two dotted line, if necessary.

At this time, a portion of fluid resin83located at region85below small die pad15(15C) also flows toward resin reservoir gate65. Thus, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region RC2. This ensures the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like).

Next, a process (step) of detaching mold die51is performed. As shown inFIG.22, plunger57is pushed upward (see the arrow). Mold resin33sealing power semiconductor elements21and the like is thus separated from lower die53. At this time, mold resin99flowing into resin reservoir63and hardened may fail to be detached from lower die53.

Then, movable pin69is also pushed upward (see the arrow) together with plunger57. Pushing movable pin69upward ensures that mold resin99is removed from lower die53. Next, as shown inFIG.23, mold resin99removed from lower die53is removed from frame37by a die punch (not shown). Further, a portion of the mold resin located at the runner and a portion of the mold resin located at the resin injection gate are separated by a die punch (not shown). In this way, semiconductor device1sealed with mold resin33shown inFIG.1toFIG.3is manufactured.

In semiconductor device1described above, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like) can be ensured. This will be explained in comparison with a method of manufacturing a semiconductor device according to a comparative example.

As shown inFIG.24, in the method of manufacturing a semiconductor device according to a comparative example, air vent79is located at a portion opposed to runner61with second cavity52binterposed in mold die51. Air vent79is one air vent among a plurality of air vents arranged on the periphery of cavity52. The same members as those of mold die52according to the embodiment are denoted by the same reference signs and will not be further elaborated unless necessary.

Fluid resin83injected from resin injection gate59into first cavity52ais injected into second cavity52bthrough runner61. In second cavity52b, fluid resin83flowing through region RC1and fluid resin83flowing through region RC2merge at region85(position87) below small die pad15(15C). At this time, the air tends to be trapped in fluid resin83. A plurality of air vents including air vent79are arranged in mold die51, and the air in fluid resin83is discharged from the air vents.

However, the air trapped in fluid resin83is less discharged at region85where fluid resins83merge. In particular, when a large volume of air is trapped, the trapped air is not discharged from the air vents and sometimes remains as voids in fluid resin83. Therefore, in the completed semiconductor device, the remaining voids may deteriorate the electrical insulation on the first main surface33eside of mold resin33(seeFIG.3and the like).

In comparison with the method of manufacturing a semiconductor device according to the comparative example, in the method of manufacturing a semiconductor device according to the first embodiment, after fluid resin83flowing through region RC1and fluid resin83flowing through region RC2merge at region85(position87), fluid resin83attempts to flow into resin reservoir63through resin reservoir gate65. Thus, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region RC2. As a result, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like) can be ensured.

In the completed semiconductor device, the portions of the mold resin located at resin injection gate59, runner61, and resin reservoir gate65(seeFIG.7and the like) are separated, so that resin trace34(seeFIG.1andFIG.6) having a coarser surface than the other portions is left on the surface of mold resin33of semiconductor device1as described at the beginning.

In particular, in the semiconductor device (seeFIG.1) sealed in second cavity52b, runner trace34cis left on first side portion33a, and resin reservoir trace34bis left on second side portion33b. Since the cross-sectional area of the runner is equal to the cross-sectional area of the resin injection gate and fluid resin is injected from the runner, runner trace34ccan be regarded as resin injection trace34a.

On the other hand, in the semiconductor device (seeFIG.6) sealed in first cavity52a, resin injection trace34ais left on first side portion33a, and runner trace34cis left on second side portion33b. The area of resin injection trace34aand the area of resin reservoir trace34bare substantially the same.

In the method of manufacturing a semiconductor device described above, in the step shown inFIG.23, mold resin99removed from lower die53is removed by a die punch from frame37and mold resin33serving as a semiconductor device. As shown inFIG.25, a notch39may be provided in frame37to efficiently remove mold resin99from mold resin33.

Notch39is formed so as to expose resin reservoir63in a state in which lead frame45is arranged in mold die51(lower die53). With this, when mold resin99is removed from mold resin33by a die punch, the die punch can be brought into direct abutment with mold resin99to efficiently remove it.

When lead frame45having such a notch39is employed, it is preferable that the distal end of movable pin69protrudes to a position about 50 μm away from the lower surface of upper die55in a state in which resin reservoir gate65is closed.

In the method of manufacturing a semiconductor device described above, resin reservoir gate65is arranged at a position closest to resin injection gate59. Specifically, mold die51in which the position (the Y-axis direction) of resin reservoir gate65and the position (the Y-axis direction) of runner61(resin injection gate59) are the same position has been described. Resin reservoir gate65may be arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61(resin injection gate59).

As shown inFIG.26, mold die51(lower die53) in which resin reservoir gate65is arranged, for example, at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis positive direction may be employed. In this case, the time taken for fluid resin83injected from runner61to reach resin reservoir gate65is longer.

Therefore, in the step of injecting fluid resin83into cavity52shown inFIG.27, even if voids remain in a portion of fluid resin83located at region85(seeFIG.18and the like), the voids are eliminated from region85(region RC2) before fluid resin83reaches resin reservoir gate65and attempts to flow into resin reservoir63. As a result, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like) can be ensured.

Furthermore, the capacity of resin reservoir63is preferably as large as possible to ensure that region85(seeFIG.18and the like) is filled with fluid resin83. To increase the capacity of resin reservoir63, as shown inFIG.28, for example, it is preferable that the length L10in the Y-axis direction is set to be long while the length L11in the X-axis direction of resin reservoir63is kept.

Thus, in the step of injecting fluid resin83into cavity52shown inFIG.29, even if voids remain in a portion of fluid resin83located at region85(seeFIG.18and the like), the voids are eliminated from region85(region RC2) reliably while fluid resin83flows into resin reservoir63. As a result, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like) can be reliably ensured.

When fluid resin (mold resin) is filled, for example, in a plurality of cavities (not shown) also arranged in the Y-axis direction, it is preferable that the length in the Y-axis direction of the resin reservoir is set to a length not exceeding the length of the cavities arranged in the Y-axis direction and the length in the X-axis direction thereof is set to be long. It is assumed that such a mold die51is used and lead frame45(seeFIG.25) including frame37having notch39is employed. In this case, it is preferable that the length in the X-axis direction of resin reservoir63does not exceed the width (the length in the X-axis direction) of the frame.

On the other hand, the length L11in the X-axis direction of resin reservoir63may exceed the width of frame37. In this case, as shown inFIG.30, it is preferable to provide a mechanism that presses mold resin99flowing into the resin reservoir and hardened from above and removes mold resin99from mold resin33.

The length L12(seeFIG.12) in the depth direction of resin reservoir63is preferably as long as possible. In order to remove mold resin99flowing into resin reservoir63and hardened from the lower die well, it is preferable that the bottom of resin reservoir63is at a position (height) equal to or higher than the bottom surface of cavity52.

Furthermore, as shown inFIG.31, for example, resin reservoir63having a region to store fluid resin may also be provided in upper die55of mold die51. In this case, in order to remove mold resin99flowing into resin reservoir63and hardened from upper die55well, it is preferable that the upper surface of resin reservoir63is at a position (height) not exceeding the upper surface of cavity52.

In such a mold die51, a sufficient capacity of resin reservoir63can be ensured, and even if voids remain in a portion of fluid resin83located at region85(seeFIG.18and the like), the voids can be reliably eliminated from region85while fluid resin83attempts to flow into resin reservoir63.

In the method of manufacturing a semiconductor device, as already explained, since fluid resin83attempts to flow into resin reservoir63through resin reservoir gate65, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region RC2. As a result, the electrical insulation on the first main surface33eside of mold resin33(seeFIG.3and the like) can be ensured.

Here, it is assumed that the thickness of mold resin33corresponding to the distance L1(seeFIG.3) from large die pad9to first main surface11eis about 500 μm. It is assumed that the thickness in the Z-axis direction of mold resin33of semiconductor device1is about 3.5 mm.

In manufacturing such a semiconductor device, in order to eliminate voids from region RC2if voids remain in a portion of fluid resin83located at region85, the volume of resin reservoir63need to be about one third of the volume of mold resin33of semiconductor device1.

In the method of manufacturing a semiconductor device described above, mold die51has resin reservoir gate65. The opening cross-sectional area of resin reservoir gate65is smaller than the opening cross-sectional area of resin injection gate59. Furthermore, resin reservoir gate65has movable pin69for controlling the flow of fluid resin into resin reservoir63.

This configuration can minimize the amount of fluid resin83flowing into resin reservoir63and can discharge voids remaining in fluid resin83. As a result, the electrical insulation of mold resin33can be ensured while the amount of discarded mold resin99(fluid resin83) is kept to the minimum. Movable pin69may simply have only the function that reliably detaches mold resin99from lower die53.

In the method of manufacturing a semiconductor device described above, fluid resin83injected into first cavity52athrough resin injection gate59flows through runner61and is injected into second cavity52b. In order to make the flow of fluid resin83in first cavity52asubstantially equal to the flow of fluid resin83in second cavity52b, it is preferable that the cross-sectional shape of resin injection gate59and the cross-sectional shape of runner61are the same cross-sectional shape. On the other hand, it is preferable that the cross-sectional shape of resin reservoir gate65is smaller than the cross-sectional shape of resin injection gate59(runner61).

With this configuration, the area of resin injection trace34aleft on a surface of semiconductor device1sealed in first cavity52aand the area of runner trace34care substantially the same, as already explained (seeFIG.6). The area of resin reservoir trace34bleft on a surface of semiconductor device1sealed in second cavity52bis smaller than the area of runner trace34c(resin injection trace34a) (seeFIG.1). In this way, resin trace34including resin reservoir trace34bis left on a surface of semiconductor device1and can be easily recognized from the appearance (mold resin33) of semiconductor device1.

(Air Vent in Mold Die)

As described above, the air in cavity52is gradually discharged from air vents79formed in mold die51while cavity52is gradually filled with fluid resin83(seeFIG.18).

FIG.32andFIG.33show air vents79located in the vicinity of resin reservoir63in mold die51, as an example of air vents79. Upper die55has an air vent79a. Lower die53has an air vent79b. Air vent79bis communicatively connected to resin reservoir63.

To efficiently discharge the air in cavity52, the gap serving as air vent79need to be large. However, for example, if the height LZ4of the gap serving as air vent79aprovided in upper die55is increased, the possibility that the fluid resin excessively flows out becomes high. Then, air vent79bis provided in lower die53so as to be opposed to air vent79ain the height direction (Z axis) so that the height of the gap serving as air vent79can be ensured.

Furthermore, the provision of resin reservoir63accelerates hardening of fluid resin flowing into resin reservoir63and prevents leakage of the fluid resin through air vent79bcommunicatively connected to resin reservoir63. Thus, the height LZ5of the gap serving as air vent79bcan be increased, compared with when resin reservoir63is not provided. As a result, the air in cavity52can be discharged to the outside of mold die51more efficiently.

In order to ensure a region (area) where lead frame45is sandwiched between upper die55and lower die53, it is preferable that air vent79aand air vent79bare arranged at positions opposed to each other in the height direction.

The width LY1of air vent79aand the width LY2of air vent79bmay be the same width or may be different from each other. The center position in the width direction (the Y-axis direction) of air vent79aand the center position in the width direction (the Y-axis direction) of air vent79bmay be the same position or may be shifted from each other.

Second Embodiment

A semiconductor manufacturing apparatus according to a second embodiment will be described. Here, a semiconductor manufacturing apparatus employing a mold die having a plurality of resin reservoirs for one cavity will be described.

(Mold Die)

A mold die as a semiconductor manufacturing apparatus will be described. As shown inFIG.34, mold die51(lower die53) has, for example, a resin reservoir63aand a resin reservoir63bas resin reservoir63. A resin reservoir gate65ais formed to communicatively connect second cavity52band resin reservoir63a. A resin reservoir gate65bis formed to communicatively connect second cavity52band resin reservoir63b.

Resin reservoir gate65ais arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis positive direction. Resin reservoir gate65bis arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis negative direction. The other configuration is similar to the configuration of mold die51shown inFIG.7andFIG.8, and the same member is denoted by the same reference sign and will not be further elaborated unless necessary.

(Method of Manufacturing Semiconductor Device)

A method of manufacturing a semiconductor device using the mold die described above will now be described.

First, a plurality of semiconductor devices including a lead frame having power semiconductor elements and the like mounted thereon before sealed with mold resin are formed in the same manner as the method of manufacturing a semiconductor described above. Next, the semiconductor devices are sealed with mold resin by transfer molding. As shown inFIG.35, lead frame45having power semiconductor elements21and the like mounted thereon is arranged in mold die51.

After lower die53and the upper die (not shown) are clamped, fluid resin83is injected into cavity52(52a) from resin injection gate59. Fluid resin83injected into first cavity52aflows through runner61and is injected into second cavity52bto gradually fill second cavity52b.

Meanwhile, as previously mentioned, fluid resin83flowing through region RC1finally flows from region RC1into region RC2and ultimately merges with fluid resin83flowing through region RC2at region85(position87) below small die pad15(15C) (seeFIG.17andFIG.19).

When fluid resin83flowing through region RC1and fluid resin83flowing through region RC2merge at region85, the air tends to be trapped in fluid resin83, and if the trapped air is not collapsed, it may remain as voids in fluid resin83(mold resin).

Next, resin reservoir gate65(65a,65b) is opened in the same manner as the step shown inFIG.20. With resin reservoir gate65(65a,65b) opened, fluid resin83in second cavity52battempts to flow into resin reservoir63athrough resin reservoir gate65aor attempts to flow into resin reservoir63bthrough resin reservoir gate65b.

At this time, a portion of fluid resin83located at region85also flows toward resin reservoir gate65. Thus, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region85.

Subsequently, the mold die is detached in the same manner as the step shown inFIG.22andFIG.23, resulting in a semiconductor device sealed with mold resin. As shown inFIG.36, in the completed semiconductor device1, specifically, two resin reservoir traces34bare left on second side portion33b.

In the method of manufacturing a semiconductor device described above, each resin reservoir gate65(65a,65b) is arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis direction (positive or negative). The time taken for fluid resin83injected from runner61to reach resin reservoir gate65is therefore longer, as with mold die51shown inFIG.26.

Therefore, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region85(position87) while fluid resin83reaches resin reservoir gate65and attempts to flow into the resin reservoir. As a result, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like) can be reliably ensured.

In mold die51described above, a sufficient volume of resin reservoir63can be ensured. In manufacturing a semiconductor device, a lead frame may have a positioning hole for a mold die. In such a case, the length in the Y direction of the resin reservoir is limited, and the capacity of the resin reservoir may be insufficient.

In the mold die described above, a sufficient capacity of resin reservoir65can be ensured with two resin reservoirs65aand65bwhile such a positioning hole (not shown) in the frame is circumvented. Since a sufficient capacity of resin reservoir65is ensured, voids are eliminated reliably even if voids remain in region85(seeFIG.19and the like).

Furthermore, in mold die51described above, wear of a die punch for removing a portion of mold resin flowing into resin reservoir65and hardened can be suppressed. Mold die51has two resin reservoirs65aand65bas resin reservoir65. This configuration can reduce the cross-sectional area of the die punch that removes a portion of mold resin flowing into each of resin reservoirs65aand65band hardened. Therefore, compared with one die punch having a large cross-sectional area, wear of the die punch can be suppressed, thereby contributing to reduction in production cost.

Third Embodiment

A semiconductor manufacturing apparatus according to a third embodiment will be described.

(Mold Die)

As shown inFIG.37, mold die51(lower die53) as a semiconductor manufacturing apparatus has, for example, a resin reservoir63aand a resin reservoir63bas resin reservoir63. A resin reservoir gate65ais formed to communicatively connect second cavity52band resin reservoir63a. A resin reservoir gate65bis formed to communicatively connect second cavity52band resin reservoir63b. In each of resin reservoir gate65aand resin reservoir gate65b, a movable pin serving as a shutter is not arranged.

As shown inFIG.38, lower die53has a protrusion93aprotruding toward resin reservoir63aand a protrusion93bprotruding toward resin reservoir63b. When a portion of mold resin flowing into resin reservoir63and hardened is removed by a die punch, frame37is supported from below by a portion of lower die53including protrusions93aand93b.

In resin reservoir63a, the length in the Y-axis direction of a portion of resin reservoir63awhere protrusion93ais located in the X-axis direction is defined as length L16a. The length in the Y-axis direction of a portion of resin reservoir63awhere protrusion93ais not located in the X-axis direction is defined as length L15a. The length L16ais preferably shorter than the length L15a.

In resin reservoir63b, the length in the Y-axis direction of a portion of resin reservoir63bwhere protrusion93bis located in the X-axis direction is defined as length L16b. The length in the Y-axis direction of a portion of resin reservoir63bwhere protrusion93bis not located in the X-axis direction is defined as length L15b. The length L16bis preferably shorter than the length L15b.

The length L15aand the length L15bmay be different lengths or may be the same length. The length L16aand the length L16bmay be different lengths or may be the same length.

In resin reservoir63a, the length in the X-axis direction of a portion of resin reservoir63awhere protrusion93ais not located in the Y-axis direction is defined as length L14a. In resin reservoir63b, the length in the X-axis direction of a portion of resin reservoir63bwhere protrusion93bis not located in the Y-axis direction is defined as length L14b. It is preferable that the length L14aand the length L14bare set to a length about half the width of frame37. This configuration can ensure a region where frame37is held down when a portion of mold resin flowing into resin reservoir63and hardened is removed by a die punch.

As shown inFIG.37, resin reservoir gate65ais arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis positive direction. Resin reservoir gate65bis arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis negative direction. It is preferable that each of resin reservoir gate65aand resin reservoir gate65bis arranged at a position as far as possible from region85(position87) below small die pad15(15C) (seeFIG.19and the like) in which fluid resin is finally filled when the lead frame is arranged in mold die51.

It is preferable that resin reservoir gate65ais arranged at a position about 0.5 to 2.0 mm away in the Y-axis negative direction from a portion extending in the X-axis direction (the upper portion in the drawing) in second cavity52b. It is preferable that resin reservoir gate65bis arranged at a position about 0.5 to 2.0 mm away in the Y-axis positive direction from a portion extending in the X-axis direction (the lower portion in the drawing) in second cavity52b. This configuration can prevent chipping of the mold resin of the semiconductor device when a portion of mold resin flowing into resin reservoir63and hardened is removed by a die punch.

The length in the Y-axis direction of resin reservoir gate65ais defined as width Wa. The length in the Y-axis direction of resin reservoir gate65bis defined as width Wb. The width Wa and the width Wb are preferably as small as possible. The width Wa and the width Wb are preferably equal to or smaller than about half the width LY1(seeFIG.9) of resin injection gate59and the width of runner61. The width Wa and the width Wb are preferably, for example, about 0.5 to 15 mm so that a portion of mold resin flowing into resin reservoir63and hardened is easily removed from lower die53.

The length (height) in the Z direction of each of resin reservoir gate65aand resin reservoir gate65bis preferably as small as possible. The length in the Z direction is preferably, for example, about 0.2 to 0.6 mm so that a portion of mold resin flowing into resin reservoir63and hardened is easily removed from lower die53. The length in the X-axis direction of each of resin reservoir gate65aand resin reservoir gate65bis defined as length L17. An appropriate length is set as the length L17in consideration of the opening cross-sectional area of resin reservoir gate65and the like.

(Method of Manufacturing Semiconductor Device)

A method of manufacturing a semiconductor device using the mold die described above will now be described. First, a plurality of semiconductor devices including a lead frame having power semiconductor elements and the like mounted thereon before sealed with mold resin are formed in the same manner as the method of manufacturing a semiconductor described above.

Next, the semiconductor devices are sealed with mold resin by transfer molding. As shown inFIG.39, lead frame45having power semiconductor elements21and the like mounted thereon is arranged in mold die51. Here, frame37of lead frame45has notches41aand41b. Notch41ais formed so as to expose resin reservoir39a. Notch41bis formed so as to expose resin reservoir39b.

Lead frame45has a suspender lead43connecting IC lead23to frame37in order to prevent IC lead23from being displaced vertically (the Z-axis direction) in cavity52when fluid resin is injected.

After lower die53and the upper die (not shown) are clamped, fluid resin83is injected into cavity52(52a) from resin injection gate59. Fluid resin83injected into first cavity52aflows through runner61and is injected into second cavity52bto gradually fill second cavity52b.

Meanwhile, as previously mentioned, fluid resin83flowing through region RC1finally flows from region RC1into region RC2and ultimately merges with fluid resin83flowing through region RC2at region85(position87) below small die pad15(15C) (seeFIG.17andFIG.19).

When fluid resin83flowing through region RC1and fluid resin83flowing through region RC2merge at region85, the air tends to be trapped in fluid resin83, and if the trapped air is not collapsed, it may remain as voids in fluid resin83(mold resin).

Next, fluid resin83is injected from runner61, so that fluid resin83in second cavity52battempts to flow into resin reservoir63athrough resin reservoir gate65aor attempts to flow into resin reservoir63bthrough resin reservoir gate65b.

At this time, a portion of fluid resin83located at region85also flows toward resin reservoir gate65. Thus, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region RC2.

Subsequently, the mold die is detached in the same manner as in the step shown inFIG.22andFIG.23, resulting in a semiconductor device sealed with mold resin. In the completed semiconductor device1, two resin reservoir traces34bare left on second side portion33b, in the same manner as semiconductor device1shown inFIG.36.

In the method of manufacturing a semiconductor device described above, each resin reservoir gate65(65a,65b) is arranged at a position (the Y-axis direction) away from the position (the Y-axis direction) of runner61in the Y-axis direction (positive or negative). Therefore, even if voids remain in a portion of fluid resin83located at region85, the voids are eliminated from region85(position87) while fluid resin83attempts to flow into resin reservoir63through resin reservoir gate65, in the same manner as described above. As a result, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3) can be reliably ensured.

Furthermore, frame37has notches41aand41b. Notch41ais formed so as to expose resin reservoir39a. Notch41bis formed so as to expose resin reservoir39b. With this configuration, when a portion of mold resin flowing into each of resin reservoirs63aand63band hardened is removed by a die punch, the die punch can be brought into contact with the portion of mold resin and efficiently remove it without coming into contact with frame37.

Furthermore, since frame37has notches41aand41b, the capacity of resin reservoirs63aand63bcan be increased by the amount corresponding to the volume of notches41aand41b(the area in the XY plane of notches41aand41b×the thickness of frame37).

In addition, since frame37has notches41aand41b, compared with when no notch is formed, the cross-sectional area of a portion connecting to the air vent (not shown) is increased. With this configuration, more air can be introduced into the air vent, and the amount of air trapped in the fluid resin can be reduced, thereby suppressing remaining voids.

Furthermore, in the method of manufacturing a semiconductor device described above, when suspender lead43is stripped by a die punch (not shown), the area where frame37is supported by lower die53is ensured because of protrusion93aand protrusion93bformed in lower die53. This configuration ensures that suspender lead43is stripped.

In the semiconductor manufacturing apparatus described above, mold die51(lower die53) has protrusion93aand protrusion93b. As shown inFIG.40, mold die51may be mold die51that does not have protrusion93aor protrusion93b. In this case, it is preferable that a portion of mold resin flowing into each of resin reservoirs63aand63band hardened and suspender lead43are simultaneously removed by a die punch (not shown).

In the semiconductor manufacturing apparatus described above, resin reservoir gate65(65a,65b) extends in the X-axis direction. As shown inFIG.41, in mold die51, the direction in which resin reservoir gate65(65a,65b) extends may be inclined in a direction intersecting the X-axis direction.

Resin reservoir gate65amay be inclined in the Y-axis direction (negative direction), for example, by an angle AL1relative to the X-axis direction. Resin reservoir gate65bmay be inclined in the Y-axis direction (positive direction), for example, by an angle AL2relative to the X-axis direction.

When such a mold die51is employed, the fluid resistance of the fluid resin flowing through resin reservoir gates65aand65bis increased, and remaining voids can be suppressed while the amount of fluid resin flowing into resin reservoirs63aand63bis reduced.

As shown inFIG.42, a step portion97may be provided, together with inclined portion67on the side closer to resin reservoir gate65at a portion of resin reservoir63. Such a step portion97can widen the gap between mold resin33and mold resin99flowing into resin reservoir63and hardened, as shown inFIG.43(dotted frame S). Thus, the hardened mold resin99can be easily removed from mold resin33by a die punch (not shown).

As shown inFIG.44, mold die51does not necessarily have a step portion in terms of keeping the capacity of resin reservoir63as much as possible. In each ofFIG.42andFIG.44, an inclined portion64provided at a portion of resin reservoir63in which resin reservoir gate65is not located is depicted by a dotted line resin.

In resin reservoir63of mold die51described above, because of the provision of resin reservoir gate65having a smaller opening cross-sectional area and communicatively connected to resin reservoir63, the flow of fluid resin83into resin reservoir63is suppressed, compared with the technique in the comparative example (PTL 1). Furthermore, since resin reservoir gate65aand resin reservoir gate65bare provided as resin reservoir gate65, the flow of fluid resin toward resin reservoir gate65is distributed.

With this configuration, even when the capacity of resin reservoir63is equivalent to about one tenth of the volume of semiconductor device1, the time taken for fluid resin83to flow into resin reservoir63can be prolonged. As a result, even if voids remain in a portion of fluid resin83located at region85(seeFIG.19), the voids can be eliminated from region85(position87) before fluid resin83flows into resin reservoir63. Furthermore, the amount of fluid resin83flowing into resin reservoir63can be reduced, thereby contributing to reduction in production cost.

In the completed semiconductor device1, resin injection trace34aand runner trace34care left on a surface of semiconductor device1sealed in first cavity52a. The area of resin injection trace34aand the area of runner trace34care substantially the same (seeFIG.6). On the other hand, runner trace34cand resin reservoir trace34bare left on a surface of semiconductor device1sealed in second cavity52b. The area of resin reservoir trace34bis smaller than the area of runner trace34c(seeFIG.1). The surface of resin trace34including resin reservoir trace34bis coarse and can be easily recognized from the appearance (mold resin33) of semiconductor device1.

Fourth Embodiment

A semiconductor manufacturing apparatus according to a fourth embodiment will be described. Here, a semiconductor manufacturing apparatus employing a mold die in which mold resin flowing into resin reservoir63and hardened can be used for mounting will be described.

First, a mold die will be described. As shown inFIG.47, in mold die51, upper die55has resin reservoir gate65and resin reservoir63. The position (the Z-axis direction) of the ceiling of resin reservoir63is arranged at a position higher than the position (the Z-axis direction) of the ceiling of cavity52.

The distance from the lower end of upper die55to the ceiling of cavity52is defined as distance L19a, and the distance from the lower end of upper die55to the ceiling of resin reservoir63is defined as distance L19b. In mold die51, resin reservoir63is formed in upper die55such that the distance L19bis longer than the distance L19a.

A method of manufacturing a semiconductor device using mold die51described above will now be described. Lead frame45having power semiconductor elements21and the like mounted thereon is formed in the same manner as the method of manufacturing a semiconductor device described in the first embodiment (seeFIG.15). Next, lead frame45(seeFIG.15) is arranged in mold die51shown inFIG.47.

Next, cavity52is gradually filled with fluid resin, in the same manner as in the step shown inFIG.16toFIG.21. In resin reservoir63, the fluid resin flowing into the resin reservoir63is hardened. Subsequently, mold die51is detached. At this time, mold resin99(seeFIG.48) flowing into resin reservoir63and hardened is not removed, and mold resin99is left connected to mold resin33. Thus, semiconductor device1(seeFIG.48) is completed with mold resin99as a sealing material mass being connected to mold resin33.

Next, as shown inFIG.48andFIG.49, semiconductor device1is mounted on an electronic circuit board101. Semiconductor device1is arranged on electronic circuit board101with conductive adhesive103interposed. At this time, mold resin99is fitted in an opening101aprovided in advance in electronic circuit board101. Cream solder, for example, is used as conductive adhesive103.

Next, conductive adhesive103is melted by reflowing and then cooled, whereby conductive adhesive103is hardened, resulting in semiconductor device1mounted on electronic circuit board101.

When semiconductor device1described above is mounted on electronic circuit board101, displacement of semiconductor device1in the reflowing step can be prevented. This will be described.

The weight of semiconductor device1having power semiconductor elements and the like mounted thereon is heavier than the weight of a conventional surface-mounted component mounted on an electronic circuit board. The adhesive force of conductive adhesive103before conductive adhesive103is hardened is weaker than the bonding force after conductive adhesive103is hardened.

In the reflowing step, therefore, the adhesive force of conductive adhesive103is unable to keep semiconductor device1fixed on electronic circuit board101, for example, when electronic circuit board101is transported, and semiconductor device1may be displaced from the mounting position on electronic circuit board101.

In semiconductor device1described above, mold resin99is left connected to mold resin33. Electronic circuit board101has opening101ain which mold resin99is fitted. When semiconductor device1is arranged on electronic circuit board101, mold resin99is fitted in opening101aprovided in electronic circuit board101.

Thus, positioning of semiconductor device1on electronic circuit board101is performed. As a result, displacement of semiconductor device1from the mounting position of electronic circuit board101can be suppressed in the reflowing step. Furthermore, since displacement of semiconductor device1from the mounting position on electronic circuit board101is suppressed, the amount of conductive adhesive103can be kept to the minimum necessary.

Fifth Embodiment

A semiconductor manufacturing apparatus according to a fifth embodiment will be described. Here, a semiconductor manufacturing apparatus employing a mold die having a plurality of resin reservoirs will be described.

First, a mold die will be described. As shown inFIG.50, mold die51(lower die53) has, for example, a resin reservoir63c, a resin reservoir63d, and a resin reservoir63eas resin reservoir63. Resin reservoir63e, resin reservoir63d, and resin reservoir63eare connected in series.

A resin reservoir gate65is formed to communicatively connect resin reservoir63cand second cavity52b. An inter-resin reservoir gate70is formed as an inter-sealing material reservoir gate that communicatively connects resin reservoirs63to each other. An inter-resin reservoir gate70ais formed as inter-resin reservoir gate70that communicatively connects resin reservoir63cand resin reservoir63d. An inter-resin reservoir gate70bis formed as inter-resin reservoir gate70that communicatively connects resin reservoir63dand resin reservoir63e. The cross-sectional areas of resin reservoir gate65and inter-resin reservoir gates70aand70bmay be the same or may be different, but preferably are smaller than the cross-sectional area of resin injection gate59.

The other configuration is similar to the configuration of mold die51shown inFIG.8, and the same member is denoted by the same reference sign and will not be further elaborated unless necessary.

A method of manufacturing a semiconductor device using mold die51described above will now be described. Lead frame45having power semiconductor elements21and the like mounted thereon is formed in the same manner as the method of manufacturing a semiconductor device described in the first embodiment (seeFIG.15). Next, as shown inFIG.51, lead frame45is arranged in mold die51.

Next, cavity52is gradually filled with fluid resin, in the same manner as in the step shown inFIG.16toFIG.21. The fluid resin in second cavity52bflows into resin reservoir63cthrough resin reservoir gate65. When resin reservoir62is filled with the fluid resin, the fluid resin flows into resin reservoir63dthrough inter-resin reservoir gate70a. The fluid resin flowing into resin reservoir63dflows into resin reservoir63ethrough inter-resin reservoir gate70b. After the fluid resin flowing into cavity52is hardened, mold die51is detached, resulting in a semiconductor device sealed with mold resin.

In the method of manufacturing a semiconductor device described above, mold die51has resin reservoir63c, resin reservoir63d, and resin reservoir63eas resin reservoir63. Resin reservoir63c, resin reservoir63d, and resin reservoir63eare connected in series by inter-resin reservoir gates70.

Therefore, compared with when a mold die having one resin reservoir having the same capacity as the total capacity of resin reservoir63c, resin reservoir63d, and resin reservoir63eis used, the rate of the fluid resin successively filling resin reservoir63c, resin reservoir63d, and resin reservoir630is decreased.

Thus, voids in region85(seeFIG.17and the like) in cavity52are easily discharged from cavity52. As a result, the electrical insulation on the first main surface33eside in mold resin33(seeFIG.3and the like) can be ensured.

In the embodiments, power semiconductor elements are taken as an example of semiconductor elements. However, the embodiments can also be applied to semiconductor elements other than power semiconductor elements.

The semiconductor manufacturing apparatuses and the manufacturing methods described in the embodiments can be combined in various ways, if necessary.

The semiconductor device includes the following aspect.

(Note 1)

A semiconductor device comprising:a lead terminal;a die pad connected to the lead terminal;a semiconductor element mounted on the die pad; anda sealing material sealing the die pad and the semiconductor element such that a part of the lead terminal is exposed, whereinthe sealing material has a first side portion and a second side portion opposed to each other at a distance from each other in a first direction,the first side portion has a sealing material trace, anda sealing material mass protrudes on the second side portion.
(Note 2)

The semiconductor device according to Note 1, further comprising an electronic circuit board having an opening,wherein the semiconductor device is mounted on the electronic circuit board with the sealing material mass being fitted in the opening.

Embodiments disclosed here should be understood as being illustrative rather than being limitative in all respects. The scope of the present invention is shown not in the foregoing description but in the claims, and it is intended that all modifications that come within the meaning and range of equivalence to the claims are embraced here.

INDUSTRIAL APPLICABILITY

The present disclosure is effectively utilized in a semiconductor device manufactured by transfer molding and a method of manufacturing the same.

REFERENCE SIGNS LIST

1power semiconductor device,3power lead,5power lead terminal,7,7a,7blead step portion,9large die pad,11a,11b,11cterminal end,13bending portion,15,15a,15b,15csmall die pad,17a,17b,17cdistal end,19conductive adhesive,21power semiconductor element,23IC lead,25IC lead terminal,27conductive adhesive,29IC element,31wire,33mold resin,33afirst side portion,33bsecond side portion,33cthird side portion,33dfourth side portion,330first main surface,33fsecond main surface,34resin trace,34aresin injection trace,34bresin reservoir trace,34crunner trace,35tie bar,37frame,39,41a,41bnotch,43suspender lead,45lead frame,51mold die,52cavity,52afirst cavity,52bsecond cavity,53lower die,53aupper surface,55upper die,55alower surface,57plunger,59resin injection gate,61runner,63,63a,63b,63c,63d,63eresin reservoir,64inclined portion,65,65a,65b,65c,65dresin reservoir gate,66a,66bportion,67inclined portion,67atop portion,69movable pin,79,79a,79bair vent,70,70a,70binter-resin reservoir gate,81tablet resin,83fluid resin,85region,87position,93a,93bprotrusion,97step,99mold resin, D diameter, W, Wa, Wb width, AL1, AL2angle, L10, L11, L12, L14a, L14b, L15a, L15b, L16a, L16b, L17length, L18distance, L19a, L19blength, LZ4, LZ5height, LY1, LY2width,101electronic circuit board,101aopening,103conductive adhesive.