JPH09213871A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which is capable of dealing with a large current and a high voltage without using an insulating board. SOLUTION: Semiconductor chips 211 to 215 are arranged on the islands 51 to 519 of a lead frame 16 to form a semiconductor device, and the islands 51 to 519 are isolated from a head rail 14 on the base of a hole inside a package, whereby the islands 51 to 519 and the head rail 14 are elongated in creepage distance between them. A recess is provided to a region where sealing material is poured, so that burrs are restrained from being exposed to the outside. In this case, the islands 51 to 519 are arranged near to the base of the package, whereby the package can be improved in heat dissipating properties, and a part of the package over the islands 51 to 519 is made thin, whereby sealing resin can be saved. Mounting holes are provided to the above thinned part of the package, and a heat dissipating fin is screwed down there, whereby the packages can be mounted high in density because the heads of screws are restrained from being exposed out of the package.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device using a package filled with a sealing material.

[0002]

2. Description of the Related Art In recent years, the size and density of electronic devices have been increasing, and power devices, which were conventionally used as individual components, are semiconductors that are incorporated in a single package together with drive circuits and protection circuits. Devices (hybrid ICs) have come to be widely used.

The conventional semiconductor device is shown in FIGS.
More specifically, the semiconductor device 102 has a package 107 formed by transfer molding of epoxy resin.
The lead portions 108 _{1 to} 108 ₆ are led out from one side surface thereof and are configured to be mounted on a printed board. Of these lead portions 108 ₁ to 108 _6, lead portions 108 ₃ disposed in the center, the electrical and the metal substrate 105 located in the package, are mechanically connected, the power device chip 106 on the surface And ceramic substrate 109
Are fixed with solder and epoxy resin, respectively.

The IC chip 103 is provided on the insulating substrate 109.
And a circuit component (not shown) are mounted on the power device chip 106 by electrical wiring made of a copper thin film.
A control circuit for operating the
16, the bonding pads 121 arranged in the control circuit are connected to the bonding pads on the chip and the lead parts 108 _{1 to} 108 ₆ to connect the wires between the chips and the chips and the lead parts 108 _{1 to} 108 ₆ . Wiring is made. Such a semiconductor device is widely used in a circuit that handles a high withstand voltage and a large current because it can reduce the mounting area and cost, but further cost reduction and miniaturization and thinning of the device are required. .

Therefore, in recent years, reduction of the insulating substrate 109 has been studied, and a semiconductor device called a multi-chip module in which elements are directly arranged on lead frames separated from each other without using the insulating substrate 109 has been developed. It has started to be done. However, due to problems of heat dissipation and creepage distance, it is difficult to incorporate a power device chip that handles a large current and a high voltage, and a solution has been desired.

[0006]

The present invention was created in order to solve the above-mentioned disadvantages of the prior art, and its object is a semiconductor device capable of handling a large current and a high voltage without using an insulating substrate.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 has a plurality of island portions fixed to a head rail by a plurality of separating portions which can be separated into two parts, and Of a lead frame having a plurality of lead portions connected to the respective island portions at the connection portions,
A semiconductor device in which a semiconductor chip is arranged on a desired island portion, each of the island portions is housed in a package formed of a sealing material in a flat plate shape, and the lead portion is led out from one side surface of the package, A recess is provided at a position where the sealing material is injected on the surface of the package, and a separation portion of the separation unit is located inside the package.

According to a second aspect of the present invention, a plurality of island portions are fixed to the head rail by a plurality of separating portions that can be separated into two parts, and a plurality of island portions are connected to the respective island portions by connecting portions. A semiconductor chip is arranged on a desired island portion of a lead frame having a lead portion and the island portion is housed in a package formed by molding a sealing material into a flat plate shape, and the lead is provided from one side surface of the package. In the semiconductor device, the island portion is located closer to the back surface of the package than the separation position of the separation portion and the lead position of the lead portion.

In this case, as in the invention described in claim 3,
5. The thickness of the sealing material between the island portion and the package surface is formed thinner than the thickness between the separated portion of the separation portion and the package surface, and the invention according to claim 4 further comprises: It may be formed thinner than the thickness between the lead-out position of the lead portion and the package surface.

Further, as in the invention described in claim 5, a mounting hole is provided in a thinly formed portion of the package, and a screw is inserted into the mounting hole to radiate fins on the back surface of the package.
When the (heat sink) is attached, the screw head may not be higher than the surface of the package.

According to such a configuration of the present invention, the semiconductor chip is arranged on a desired island portion of the plurality of island portions, and the semiconductor chip and the lead portion are connected by a gold wire wire or the like, and the semiconductor chip is placed in the mold. When each island part is housed, the lead part is led out of the mold, the sealing material is injected, and a flat package is formed by the transfer molding method, and the island part and the head rail, and the lead part and the tie bar are separated. A semiconductor device called a multi-chip module in which each island portion is housed inside the package can be obtained.

In the transfer molding, if the separating portion of the separating portion is located inside the package, the separating portion left on the island portion side when the island portion and the head rail are separated from each other. Since the separated portion can be exposed at the bottom of the hole formed after the separation, the creeping distance of the semiconductor device can be increased by the depth of the hole. In particular, when the sealing material is injected into the mold, it is convenient to form a recess in the injection portion of the sealing material of the molded package, because burrs and the like do not stick out to the package surface. .

In the semiconductor device having the lead frame and the package as described above, when the island portion of the lead frame is located closer to the back surface than the separated portion of the separation portion or the lead-out position of the lead portion, This is convenient because the thermal resistance between the island portion and the radiation fin is reduced. In this case, the thickness of the sealing material between the island portion and the package surface is made thinner than the thickness between the separated portion of the separating portion and the package surface, and the lead position of the lead portion and the package surface. And the sealing material can be saved.

Further, in this case, when mounting holes are provided in the thinly formed portion so that the screw heads are not higher than the package surface when the heat radiation fins are mounted on the back surface of the package, it is possible to mount the mounting holes. Moreover, the screw head does not get in the way, and the mounting density can be improved.

[0015]

Embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, reference numeral 2 denotes a multi-chip module type semiconductor device according to an embodiment of the present invention, in which epoxy resin is transfer-molded.
The package 3 has a substantially rectangular shape with a thickness of about 4 mm and a planar external shape of about 50 mm × 20 mm. The lead portions 8 ₁ to 8 ₁₉ are led out from the one side surface 50 of the package 3 so that they can be processed into a ZIP array by forming in a subsequent step.

A lead frame 16 as shown in FIG. 2A is used in this semiconductor device 2, and island portions 5 _{1 to} 5 ₁₉ are housed inside the package 3, and each lead portion 8 ₁ to 8 ₁₉ is connected to the island portions 5 _{1 to} 5 ₁₉ by the connecting portions 7 _{1 to} 7 ₁₉ , respectively. Each lead 8 ₁
8 _19, the initial state immediately after the transfer molding, are connected to each other by tie bars 10.

A perspective view of the lead frame 16 is shown in FIG. Of the island portions 5 _{1 to} 5 ₁₉ , the island portions 5 ₁ , 5 ₁₀ and 5 ₁₉ are formed wider than the other island portions, and are configured so that semiconductor chips can be arranged. Island area 5 ₁ , 5 ₁₉
Is connected to the head rail 14 by the separating portions 9 _{1 to} 9 ₃ and is configured so as not to bend during transportation or transfer molding. Further, the tip ends of the lead portions 8 ₁ to 8 ₁₉ are connected to the side rails 13 so that they can be handled integrally.

[0018] The separation portion 91 _to 93 ₃ is formed into a triangular shape, a separating member 91 _{1-91 3} provided in the head rail 14 flush, is shaped similarly to the triangular shape, the island portion 5 ₁ , 5 ₁₉ and the separating member 92 _{1-92 3} erected from the upper end surface of, and is constituted by connecting substantially perpendicularly to a common one vertex of each other, becomes therefore a constricted central portion shape The separating portion is configured, and the separating member 91
_{1-91 3} and the separating member 92 _{1-92 3} are as likely to be separated.

When the lead frame 16 described above undergoes a die bonding process, the power device chips 21 ₁ and 21 ₂ are directly fixed onto the island portions 5 ₁ and 5 ₁₉ by soldering, respectively, as shown in FIG. It Further, the semiconductor chip 21 ₃ is placed on the island portion 5 ₁₉ and the semiconductor chip 2 3
1 ₄ and 21 ₅ are directly fixed on the island portion 5 ₁₀ by silver paste, and a semiconductor chip is provided without using an insulating substrate.

Further, the tip portions of the island portions 5 _{1 to} 5 ₆ and the island portions 5 _{14 to} 5 ₁₉ are extended so as to be located near the center of the package 3, and the gold wire 22 is attached in the wire bonding step. Used to connect the semiconductor chips 21 _{3 to} 21 ₅ and to connect the semiconductor chips 21 _{1 to} 21 ₅
It is configured such that ball bonding can be easily performed when the and the island portions 5 _{1 to} 5 ₁₉ are connected. Therefore, the central position far from the island portion 5 _{2-5 6} and the island portion 5 _{14-5 18} is made more flexible lead frame material will be molded elongated. Therefore, the resin sheets 11 ₁ and 11 ₂ are provided on the surfaces of the island portions 5 _{1 to} 5 ₇ and the island portions 5 _{13 to} 5 _19, and the island portions 5 _{2 to} 5 ₆ and 5 are formed.
₁₄ 5 _18, the opposite ends island portions 5 _1, 5 _7, 5
_13, 5 ₁₉ or be secured to, and is prevented flex during transport and transfer molding.

The lead frame 16 constructed in this way
Is placed in the mold used for transfer molding in the molding step, and epoxy resin is injected from the injection hole of the mold inner peripheral surface where the cut-off parts 9 _{1 to} 9 ₃ are located,
The package 3 is formed as shown in FIG.

At the time of the transfer molding, since the lead portions 8 ₁ to 8 ₁₉ and the tie bar 10 are located outside the cavity of the mold, each lead portion 8 ₁ to 8 ₁₉
8 ₁₉ is led out from one side surface 50 of the package 3. On the other hand, a concave portion 4 is formed on the side surface opposite to the one side surface 50, and the injection hole is at the position of the concave portion 4. Therefore, the epoxy resin is injected from the position where the concave portion 4 is formed. When the package 3 is taken out of the mold, the burr is housed in the recess 4 and does not appear on the surface. In addition, the separation members 91 ₁ to
The reference numeral 91 ₃ is adapted to be projected from the recess 4 to the outside of the package 3.

Further, connecting portions 7 _{1 to} 7 ₁₉ are provided between the island portions 5 _{1 to} 5 ₁₉ and the lead portions 8 ₁ to 8 ₁₉ , respectively, and these connecting portions 7 _{1 to} 7 ₁₉ are provided. The plane in which the lead portions 8 ₁ to 8 ₁₉ are located is higher than the plane in which the island portions 5 _{1 to} 5 ₁₉ are located by the amount of the step to be created. When the lead frame 16 in the state of (4) is placed in the mold and transfer molding is performed, the respective island portions 5 _{1 to} 5 ₁₉ are located near the back surface of the package 3, and lead is performed from near the center in the thickness direction of one side surface of the package 3. The parts 8 ₁ to 8 ₁₉ are configured to be led out.

In addition, during transfer molding,
A strip-shaped thin portion 6 is provided on the surface of the package 3 near the center in the vertical direction. Since the island portions 5 _{1 to} 5 ₁₉ are located between the thin portion 6 and the back surface, the surface of the package 3 provided with the thin portion 6 and the island portions 5 _{1 to} 5 ₁₉ The thickness of the epoxy resin between the two is formed thinner than the thickness between the portion where the separating portions 9 _{1 to} 9 ₃ are left and the surface of the package 3, and the package 3 to the lead portions 8 ₁ to 8 _{19 are formed.} Is formed to be thinner than the thickness between the position where the is extracted and the surface of the package 3, and the amount of epoxy resin used is reduced.

After performing such transfer molding, the tie bar 10 is cut and the separating portion 9 is cut.
_{1-9 3} each island from the constricted portion and to separate the head rail 14 5 _{1-5 19,} and respective lead portions 8 _{1-8 19}
Are electrically and mechanically separated while being fixed with an epoxy resin, and the semiconductor device 2 shown in FIG. 3D is obtained.

FIG. 5 shows a state in which each of the lead portions 8 ₁ to 8 _{19 is formed} into a ZIP array and a radiation fin is attached to the semiconductor device 2. Mounting holes 15 ₁ and 15 ₂ are provided at the left and right ends of the thin portion 6, and a radiation fin 17 is arranged on the back surface of the package 3, and screws (not shown) inserted into the mounting holes 15 ₁ and 15 ₂ are provided. When screwed by, the package 3 and the radiation fin 17 are brought into close contact with each other. that time,
Since the mounting holes 15 ₁ and 15 ₂ are provided in the thin portion 6,
It is possible that the screw head does not protrude from the surface of the package 3.

The creepage distance on the side of the lead portions 8 ₁ to 8 _{19 at} this time is a linear distance between each of the lead portions 8 ₁ to 8 ₁₉ and the heat radiation fin 17, but is not limited to the island portions 5 ₁ , 5 _19. On the side, the head rail 14 is formed at the constricted portion of the separating portions 9 _{1 to} 9 _3.
The separating member 92 ₁ inside the package 3 when the
To 92 ₃ and is left, the separation member 91 _{1-91 3} the separation member 92 _{1-92 3} inside hole 19 Deki been removed is
Since the end portion of is exposed, the creepage distance at that portion is the sum (a + b) of the depth a of the hole 19 and the distance b from the opening end of the hole 19 to the heat dissipation fin 17, and the creepage distance is Can be large. Here, the creepage distance is set to 2 mm or more.

Unlike the semiconductor device 2 described above, FIG.
Like the semiconductor device 2'shown in (a), the lead portions 8 ₁ to 8
Lead portion 8 without changing the size of the ₁₉ side of the creepage distance f _'1 ~
'If you lose the step between the _19, the package 3' 8 _'19 and the island portion 5' _1-5, the upper thickness d _1, the thickness d ₂ of the central portion, the lead portion side thickness d ₃ together Since the values are the same, a large amount of epoxy resin is required due to the inability to provide a thin portion, which is uneconomical. Further, in this case, since the epoxy resin between the island portions 5 ′ _{1 to} 5 ′ ₁₉ and the heat radiation fin becomes thick, the heat radiation property deteriorates.

On the other hand, unlike the semiconductor device 2 "shown in FIG. 1B, the island portion 5" ₁
If the island portions 5 " _{1 to} 5" ₁₉ are arranged near the back surface of the package 3 "with the heights of ~ 5" ₁₉ and the lead portions 8 ₁ to 8 ₁₉ being the same, the thickness g of the upper portion of the package 3 "g The thickness h _{1 in the} vicinity of the center and the thickness h _{2 in the} lower portion on the lead portion side can be made smaller than the above, but the creepage distance j on the lead portion 8 " ₁ to 8" ₁₉ side becomes short and high voltage cannot be handled. The semiconductor device 2 of the present invention does not have such an inconvenience.

Although the case where the package is made of the epoxy resin has been described above, the sealing material is not limited to this, and for example, a silicone resin can be used. Also, the method of molding the package is not limited to transfer molding, but the recess 4 is particularly effective as a burr countermeasure when molding epoxy resin by transfer molding.

Further, the cut-off portion of the present invention is not limited to the one that connects two separate members 91 ₁ to 91 ₃ and 92 ₁ to 92 ₃ in one corner a in the common, e.g., FIG. 7 ( As shown in the separation part 9 ′ in a), the separation member 97a vertically standing on the island portion and the separation member 97b provided on the head rail side are connected substantially vertically at the narrow portion 87, The narrow portion 87 may be cut and separated when the separating member 97b is pulled.

A separating member 9 which is erected vertically on the island portion side, like a separating portion 9 '' in FIG.
8a and a separating member 98b provided on the head rail side are provided so as to be substantially perpendicular to each other.
When 8b is pulled, it may be separated by a groove 88 provided in the separating member 98b so that the head rail is removed from the island portion side.

In this case, instead of the groove 88, a notch 89 is provided in the separating member 99b on the head rail side to form a separating member 99a on the island portion side, as in the separating portion 9 '''shown in FIG. May be connected with.

In short, when the head rail is removed from the island portion by pulling the head rail side or the like, the portions of the cut-off portions 9'-9 '''left on the island portion side are located in the package, and If the surface exposed portion is at the bottom of the hole, the creepage distance can be increased and is included in the present invention.

[0035]

Since the creepage distance can be increased, it is effective for a semiconductor device that handles a high voltage, and the deburring work in the manufacturing process can be omitted. It is possible to incorporate a power device with a large current and a high breakdown voltage without incorporating an insulating substrate. Since the heated island portion can be located near the radiation fins, the heat radiation is good, and the package of that portion can be formed thin, so that the sealing material can be saved and a low-cost semiconductor device can be manufactured. . If the mounting holes for the heat radiation fins are provided in the thin portion, the screw heads do not protrude from the package surface, so that the mounting density on the printed circuit board can be improved.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining the manufacturing process of the semiconductor device (a): state of lead frame (b): state of die-bonding and wire-bonding

FIG. 3 (c): Molded state (d): Cutting state

FIG. 4 is a perspective view of a lead frame.

FIG. 5 is a diagram for explaining a creepage distance.

6A and 6B are diagrams for explaining the thickness and creepage distance of the package.

FIG. 7 (a) to (c): Example of separation part

8A is a perspective view of a conventional semiconductor device, FIG. 8B is a plan view of the inside, and FIG. 8C is a side view of the inside.

[Explanation of symbols]

2 ... Semiconductor device 3 ... Package 4 ... Recessed portion 5 _{1 to} 5 ₁₉ ... Island portion 6 ... Thin portion 7 ₁ ...
7 ₁₉ ...... Connection part 8 ₁ to 8 ₁₉ ...... Lead part 9 _{1 to} 9 ₃ ...... Disconnection part
10 tie bar 11 ₁ 11 ₂ resin sheet 13 side rail 14 head rail 15 ₁ 15 ₂ mounting hole 16 lead frame 17 radiating fin 1
9 ...... hole 21 _{1 to} 21 ₅ ...... semiconductor chip 22 ...... gold wire 50 ...... one side surface of package 91 _{1 to} 91 ₃ , 92 ₁
~ 923 ₃ Separation member

Claims (5)

[Claims] 1. A lead frame having a plurality of island portions fixed to a head rail by a plurality of detachable portions that can be separated into two portions, and a plurality of lead portions each connected to each of the island portions by a connecting portion. , A semiconductor device in which a semiconductor chip is arranged on a desired island portion, each of the island portions is housed in a package formed by molding a sealing material into a flat plate, and the lead portion is led out from one side surface of the package. A semiconductor device is characterized in that a recess is provided at a sealing material injection position on the surface of the package, and a separation part of the separation part is located inside the package. 2. A lead frame having a plurality of island portions fixed to a head rail by a plurality of detachable portions that are separable into two portions, and a plurality of lead portions each connected to each of the island portions by a connecting portion. , A semiconductor device in which a semiconductor chip is arranged on a desired island portion, each of the island portions is housed in a package formed by molding a sealing material into a flat plate, and the lead portion is led out from one side surface of the package. The semiconductor device is characterized in that the island portion is located closer to the back surface of the package than the separation position of the separation portion and the lead-out position of the lead portion. 3. The thickness of the sealing material between the island portion and the package surface is formed thinner than the thickness between the separated portion of the separation portion and the package surface. 2. The semiconductor device according to 2. 4. The thickness of the sealing material between the island portion and the package surface is formed thinner than the thickness between the lead-out position of the lead portion and the package surface. The semiconductor device according to claim 2 or claim 3. 5. A mounting hole is provided in a thinly formed portion of the package, and when a screw is inserted through the mounting hole and a heat radiation fin is mounted on the back surface of the package, the screw head is located above the surface of the package. The semiconductor device according to any one of claims 2 to 4, wherein the semiconductor device is configured so as not to increase in height.