JP2003051560A - Package of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent imperfect wire bonding to inner leads of main circuit terminals which are subjected to insert molding on an enveloping case, by improving the shape of an adhesive agent spreading trench on a bottom surface of the case bonded to a metal base. SOLUTION: In a package structure, the metal base 1 mounting a power circuit is bonded to the bottom surface of the enveloping case 2 which is collectively formed integrally with terminals, and wire bonding is performed by an ultrasonic compression bonding method on parts between the inner leads 4a of the main circuit terminals 4 which are subjected to insert molding on the case 2, and the power circuit. In the structure, corresponding to parts in which at least the inner leads of the main circuit terminals overlap vertically with inner leads of other terminals, a trench width enlarging part 2b wherein trench width is enlarged partially toward the lower surface regions of the inner leads is formed in a recessed trench 2a which is formed on the bottom surface of the case 2 and used for spreading adhesive agent. The lower surface region of the inner leads 4a is bonded perfectly to the metal base 1, so that ultrasonic bonding of wires is stabilized.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an intelligent power module (IP) applied to an inverter device or the like.
M: relates to the package structure of a semiconductor device targeted for Intelligent Power Module).

[0002]

2. Description of the Related Art First, as an example of an IPM applied to the above-mentioned inverter device, the module assembly structure is shown in FIG.
(b) to FIG. 4 and its equivalent circuit are shown in FIG. In the figure, 1 is a metal base (copper base) for heat dissipation, 2 is a terminal integrated type enclosure case which is a resin molded product, 3 is a top cover attached to the upper surface of the enclosure case 2, and 4 is an enclosure case 2 Input / output main circuit terminals (copper frame terminals) for the power circuit integrally insert-molded with, 5 is an external terminal block for the control circuit, 6 is a solder mount on a metal base 1 via an insulating circuit board such as a ceramic board. Power circuit (inverter circuit), 7 is a control circuit arranged above the power circuit 6 in a two-story system, and 8 is integrated with the inner peripheral side of the outer casing 2 so as to connect between the power circuit 6 and the control circuit 7. The molded relay terminal block 9 is a bonding wire for internal wiring, and the bonding wire 9 is provided between each semiconductor element of the power circuit 6 and the conductor pattern of the circuit board, and a circuit board. A main circuit terminal 4 are wired between the relay terminals 8.

Here, the power circuit 6 of the illustrated example is a set of seven power semiconductor devices (IGBTs) 6a corresponding to the upper arm circuit, the lower arm circuit and the brake circuit of the inverter circuit shown in FIG. 5, and free wheeling. The diodes 6b are separately mounted on the circuit boards (ceramic boards) 6c-1 and 6c-2 which are divided into two pieces and arranged side by side. The diodes 6b correspond to the conductor patterns of the circuit boards 6c-1 and 6c-2. As described below, the main circuit terminals 4 are arranged in a line on the left and right sides and insert-molded in the enclosure case 2. On the other hand, the control circuit 7 has a structure in which various circuit components including a driving IC for the power semiconductor element 6b are mounted on a printed circuit board,
As shown in Fig. 2 (b), the lead protruding inside the case from the external terminal block 5 of the control circuit and the relay terminal block 8
Is installed so as to straddle the lead that stands up from.

Further, regarding terminal symbols marked on the case lid 3 in FIG. 2 (a), P and N are DC input terminals,
U, V, and W are three-phase AC output terminals, B is a terminal of the brake unit, and Nos. 1 to 19 are terminal numbers of control terminals. The main circuit terminals (copper frame terminals) 4 corresponding to the terminal symbols P, N, U, V, W are arranged in a layout as shown in FIGS. Regarding AC output terminals of V and W phases, U, V and W whose inner leads are formed on the two left and right circuit boards 6c-1 and 6c-2 described above.
An inner lead 4a extending in a bifurcated manner so as to straddle the conductor pattern corresponding to the phase and bent in an L shape as shown in FIG. As described above, wire bonding is performed between the tip portion of the inner lead 4a and the power circuit 6 for connection. Also, in this terminal arrangement, as shown in the drawing, V,
The inner leads of the W-phase terminal and the inner leads of the N- and U-phase terminals are arranged so as to be vertically overlapped with each other.

The IPM having the above structure is assembled by the following procedure. First, the circuit board 6c of the power circuit 6 is solder-mounted on the metal base plate 1, and then the terminal-integrated enclosure case 2 is bonded onto the metal base plate 1 with an adhesive. In this state, the power circuit board 6c Conductor pattern and enclosure case 2
Inner lead 4 of main circuit terminal 4 protruding inward from
The internal wiring is performed by performing wire bonding between the terminal a and the lead of the relay terminal block 8 by the ultrasonic pressure bonding method. Next, after assembling the external terminal block 5 of the control circuit near the center of the upper surface of the outer case 2, the tip end of the terminal lead protruding inward from the terminal block 5 and the relay terminal block 8 are projected upward. The printed circuit board of the control circuit 7 is laid across the two leads in a two-story manner and soldered. Next, in this assembled state, a gel filler (for example, silicone gel) is injected into the package to seal the main circuit 6 and the control circuit 7, and finally, the outer case 2
The upper lid 3 is put on and fixed with an adhesive.

Here, in order to join the metal base 1 and the outer case 2 with an adhesive, the adhesive is applied in advance along the peripheral area of the bottom surface of the outer case 2 facing the outer peripheral edge of the metal base 1. The shallow groove 2a (see FIG. 2 (b)) is formed, and the fluid adhesive supplied from an adhesive dispenser (not shown) that moves along the route of the groove 2a is evenly distributed. Apply and then enclose the case 2 on the metal base 1.
Are piled up, and the adhesive is hardened to bond them while applying a pressure.

The inner lead 4a of the main circuit terminal 4
In the ultrasonic bonding process for connecting between the power circuit 6 and the circuit board 6c of the power circuit 6, as is well known, the module assembly is placed on the work holder of the ultrasonic bonder with the metal base 1 facing down, and the inner of the main circuit terminal 4 is inserted. Ultrasonic vibration is applied while pressing the bonding wire (Al wire) stacked on the lead 4a with the wedge attached to the horn of the bonder.
As a result, impurities (oxides) on the joint surface are removed by the friction of ultrasonic vibration, and the wire is plastically deformed by the heat generated on the joint surface at the same time, so that the electrode portion and the wire are solid-phase joined.

[0008]

By the way, it has been found that the IPM having the above-mentioned structure has the following problems to be solved in the assembling process. That is, (1) ultrasonically attach a bonding wire 8 to the tip of the inner lead 4a of the main circuit terminal 4 which is insert-molded integrally with the outer case 2 while the outer case 2 is bonded to the metal base 1 with an adhesive. At the time of bonding by the crimping method, the case portion covering the lower surface area (see FIG. 2 (b)) of the inner lead 4a drawn to the inner peripheral side of the outer case 2 is completely adhered to the metal base 1. If it is not, the exciting force of ultrasonic vibration applied from the bonder to the bonding wire 9 escapes and does not act effectively on the bonding portion, which causes defective bonding.

With respect to this point, in the conventional structure, the concave groove 2a which is an adhesive coating surface formed along the peripheral area of the bottom surface of the outer casing 2 is formed along the outer peripheral edge of the metal base 1, and
While the groove width of the recessed groove 2a is set to the minimum width required to secure the required adhesive strength, the application amount (consumption amount) of the adhesive is suppressed as much as possible to achieve cost reduction. As described with reference to FIG. 4, in the portion where the L-shaped inner leads 4a of the main circuit terminal 4 are vertically overlapped and protrude toward the inner peripheral side of the outer casing 2, the upper inner lead is located inside the lower inner lead. Since it is located at, the inner lead on the upper side is projected to the inner peripheral side from the concave groove 2a serving as the adhesive application surface. For this reason, the lower surface area of the inner lead on the tip side is not completely adhered to the metal base 1, and as a result, when the bonding wire 9 is ultrasonically bonded to the inner lead 4a in the wire bonding process, the above-mentioned bonding failure occurs. Is likely to occur.

In order to prevent the occurrence of such a defective bonding, it is conceivable that the groove width of the above-mentioned groove 2a is set to be wide in its entire area in advance.
It is not practical to widen the groove width of a more than necessary because the amount of adhesive applied (consumption amount) increases and the product cost increases. (2) Also, the concave groove 2a formed in the peripheral area of the bottom surface of the outer casing 2
In the step of applying the adhesive to the adhesive, the adhesive dispenser is used as described above, the nozzle of the dispenser is aligned with the start point defined on the route of the concave groove 2a, and the supply of the adhesive is started. The adhesive is applied while moving the dispenser nozzle along the route of the groove 2a, and the adhesive supply of the dispenser is stopped when the dispenser nozzle moves to the end point of the groove route. The amount of adhesive applied may be slightly excessive compared to other ranges due to the timing difference between the start of supply of the agent and the start of movement of the dispenser, and the end point of the adhesive dripping from the dispenser nozzle. Is inevitable.

Therefore, in the subsequent assembling process, the outer case 2
When is superimposed on the metal base 1 and pressure is applied,
At the start / end point, there is a problem that the excess adhesive overflowing from the concave groove 2a sticks out to the inner peripheral side of the outer case 2 and adheres to the circuit board of the power circuit 6 to stain the bonding surface of the conductor pattern. May cause. The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor device package improved so as to solve the above-mentioned problems in the assembly process and improve the quality of products.

[0012]

In order to achieve the above object, according to the present invention, a metal base on which a power circuit is mounted is combined with a terminal-integrated enclosure case and an upper lid, and they are bonded together. A semiconductor device package with a structure.In the outer case, the main circuit terminals for input and output for the power circuit are arranged on the left and right sides and insert-molded, and the outer case of the outer case faces the outer peripheral edge of the metal base. A groove is formed in the peripheral area of the bottom surface to serve as an adhesive application surface, the adhesive is applied to the groove and is joined to a metal base, and then bent into an L-shape and drawn out to the inner peripheral side of the enclosure case. Among the main circuit terminals insert-molded in the outer case, the main circuit terminals are wire-bonded by an ultrasonic pressure bonding method between the inner leads of the main circuit terminals and the power circuit.
At least the inner lead corresponds to a terminal that vertically overlaps with the inner lead of another terminal, and the groove width of the concave groove formed on the bottom surface of the case is partially enlarged toward the lower surface area of the inner lead (claim Item 1).

When the adhesive is applied to the concave groove formed on the bottom surface of the outer case, the adhesive is applied to the groove width enlarged portion, so that the amount of the adhesive applied is greater than necessary. In the state where the enclosure case is superposed on and joined to the metal base without increasing the thickness, the lower surface area of the inner lead of the main circuit terminal is completely bonded to the metal base. Accordingly, in the subsequent wire bonding process by ultrasonic pressure bonding, the inner lead of the main circuit terminal and the bonding wire can be reliably bonded to each other to prevent defective bonding.

Further, according to the present invention, there is provided a semiconductor device package having a structure in which a metal base on which a power circuit is mounted is combined with a terminal-integrated enclosure case and an upper lid, and the two are bonded together. A groove is formed in the peripheral area of the bottom surface of the outer case facing the periphery of the adhesive case, and the adhesive supplied from the adhesive dispenser is applied along the groove to apply the adhesive to the metal base. In the case where the surrounding cases are overlapped and pressure-bonded, the groove width of the concave groove is set to the outer peripheral side of the groove at a position corresponding to the adhesive application start / end point defined on the route of the concave groove. It is set so as to partially enlarge the image (claim 2).

According to the above, when the adhesive supplied from the adhesive dispenser is applied along the route of the concave groove, and when the pressure is applied by stacking the enclosure case on the metal base, the application of the adhesive is started. ， At the end point, the adhesive applied a little more than the fixed amount escapes to the groove width expansion part, and as a result, the excess adhesive sticks out to the inside of the enclosure case and adheres to the power circuit board. Can be avoided. This facilitates control of the amount of adhesive applied.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
Description will be made based on the examples shown in (a) to (c). In the drawings of the embodiments, members corresponding to those in FIGS. 2 to 4 are designated by the same reference numerals, and the description thereof will be omitted. The IPM package of the illustrated example is basically the same as the structure shown in FIGS.
The outer case 2 has main circuit terminals 4 for input and output to the power circuit (terminal symbols P, N, U, V, W attached to each terminal).
And B correspond to the terminal symbols shown in FIG. 3) and are insert-formed side by side in a line.
In contrast to the tip of the inner lead 4a bent in a letter shape protruding toward the inner peripheral side of the outer case 2, in this embodiment, as shown in FIG. The concave groove 2a (the portion shown by hatching in the figure) which is an adhesive application surface formed along the side is formed in the following pattern.

That is, the concave grooves 2a are basically formed to have the same width along the route corresponding to the peripheral edge of the metal base 1 joined to the outer case 2, but especially the right and left side main circuits are arranged side by side. In the range in which the terminals 4 are arranged, at least the inner leads 4a of the main circuit terminals 4 correspond to the portions vertically overlapping the inner leads 4a of the other terminals, and are indicated by a to d in the figure.
In each of the portions shown by, the groove width enlarged portion 2b is formed so that the groove width of the concave groove 2a is partially enlarged toward the lower surface region of the inner lead tip portion, and the groove width enlarged portion 2b is included. In the range, the concave groove 2a is formed in a pattern having a wavy shape.

Further, in the step of applying the adhesive to the groove 2a using an adhesive dispenser, a portion corresponding to the start / end point on the adhesive application route (usually an enclosure case having a rectangular outer shell) 2) is defined on the short side of 2), the groove width enlarged portion 2c is formed by partially enlarging the groove width of the concave groove 2a toward the outer peripheral side of the groove. It has a dam function that allows excess adhesive to escape.

With the above structure, when the adhesive is applied to the concave groove 2a formed on the bottom surface of the outer casing 2, the adhesive is also applied to the groove width enlarged portion 2b, so that the metal base is formed. In the state where the outer case 2 is superposed on and bonded to the outer case 1, the lower surface region of the inner lead 4a of the main circuit terminal 4 is completely bonded to the metal base 1. As a result, in the subsequent ultrasonic bonding step, the inner leads 4a of the main circuit terminals 4 and the bonding wires 9 (see FIGS. 2 and 3) can be reliably bonded without causing defective bonding.

Further, after applying the adhesive supplied from the adhesive dispenser along the route of the concave groove 2a, when the pressure is applied by stacking the outer case on the metal base, the adhesive is applied. The adhesive applied a little more than the fixed amount at the start and end points comes to escape to the groove width enlarged portion 2c. As a result, it is possible to prevent the excess amount of the adhesive from sticking out to the inside of the enclosure case 2 and adhering to the circuit board of the power circuit 6 (see FIGS. 2 and 3), which becomes an obstacle in the subsequent wire bonding process. . This facilitates control management of the adhesive application amount in the step of applying the adhesive to the concave groove 2a using the adhesive dispenser.

In the illustrated embodiment, the groove width enlarged portion 2b is limited to the specified portion corresponding to the inner lead 4a of the main circuit terminal 4, but all inner leads of the main circuit terminal 4 are formed. It can also be formed by forming it at a corresponding portion.

[0022]

As described above, the structure of the present invention has the following effects. (1) A semiconductor device package that has a structure in which a metal base on which a power circuit is mounted and a terminal-integrated enclosure case, and an upper lid are combined and the two are bonded together. The main circuit terminals for output are arranged on the left and right sides and insert-molded, and at the same time, a groove is formed in the peripheral area of the bottom surface of the enclosure case as an adhesive application surface facing the outer peripheral edge of the metal base. A wire formed by ultrasonic bonding between the inner lead of the main circuit terminal and the power circuit, which is bent in an L shape and is drawn out to the inner peripheral side of the outer case in a state where the adhesive is applied and bonded to the metal base. Among the main circuit terminals, which have been internally wired by bonding, at least the inner lead corresponds to the terminal vertically overlapping the inner lead of another terminal, and the groove width of the concave groove formed on the bottom surface of the case. By partially enlarging it toward the lower surface area of the inner lead, the main circuit described above can be used in a state where the enclosure case is overlaid and adhered to the metal base without increasing the adhesive application amount more than necessary. Since the lower surface area of the inner lead of the terminal is completely adhered to the metal base, the inner lead of the main circuit terminal and the bonding wire are securely joined in the wire bonding process by the ultrasonic bonding method which follows. Therefore, the occurrence of defective bonding can be effectively prevented.

(2) Further, the groove width of the concave groove is partially enlarged toward the outer peripheral side of the groove at a position corresponding to the adhesive application start / end point defined on the route of the concave groove. According to the configuration of Item 2, when the adhesive supplied from the adhesive dispenser is applied along the route of the concave groove, and the pressing force is applied by overlapping the outer case on the metal base, the start, At the end point, the adhesive applied a little more than the fixed amount will escape to the groove width expansion part, and as a result, excess adhesive will stick out to the inside of the enclosure case and adhere to the power circuit board. This can be avoided and the control of the amount of adhesive applied can be controlled easily.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an IPM package according to an embodiment of the present invention, in which (a), (b) and (c) are respectively a plan view of an outer case and a side view showing an arrangement of main circuit terminals, And bottom view of enclosure

FIG. 2 is an overall view of an IPM to which the present invention is applied,
(a) is an external plan view, (b) is a cross-sectional side view of (a)

FIG. 3 is a plan view showing an assembled state in which an IPM of FIG. 2 has a metal base on which a power circuit is mounted and an outer case is joined to perform wire bonding.

FIG. 4 is a diagram showing an arrangement of main circuit terminals in FIG.
(a) to (c) are terminal arrangement diagrams showing the U, V, and W phase AC output terminals separately.

5 is an equivalent circuit diagram of FIG.

[Explanation of symbols]

1 Metal base 2 Envelope case 2a Groove width 2b corresponding to inner lead of main circuit terminal 2c Groove width expansion part corresponding to inner lead of main circuit terminal 2c Groove width expansion part 4 corresponding to start / end points of adhesive application 4 Main Circuit terminal 4a Inner lead 6 Power circuit 6a Power semiconductor element 6c-1, 6c-2 Circuit board 9 Bonding wire

Claims (2)

[Claims] 1. A package of a semiconductor device having a structure in which a metal base on which a power circuit is mounted, a terminal-integrated enclosure case, and an upper lid are combined and bonded to each other. The main circuit terminals for input and output are arranged on the left and right sides and insert-molded, and at the same time, a concave groove is formed on the peripheral area of the bottom surface of the enclosure case as an adhesive application surface facing the outer peripheral edge of the metal base. Ultrasonic pressure bonding method between the inner lead of the main circuit terminal and the power circuit, which is bent in an L shape and is pulled out to the inner circumference side of the outer case in a state where the groove is coated with an adhesive and joined to the metal base. Of the main circuit terminals, at least the inner leads corresponding to the terminals vertically overlapping the inner leads of the other terminals of the main circuit terminals. A package of a semiconductor device, wherein a groove width of a groove is partially enlarged toward a lower surface region of an inner lead. 2. A package of a semiconductor device having a structure in which a metal base on which a power circuit is mounted, a terminal integrated type enclosure case, and an upper lid are combined and bonded to each other, the package being opposed to the peripheral edge of the metal base. A groove is formed on the bottom surface of the outer case as an adhesive application surface, the adhesive supplied from the adhesive dispenser is applied along the route of the groove, and then the outer case is attached to the metal base. In a case where they are overlapped and pressure-bonded, the groove width of the concave groove is directed toward the outer peripheral side of the groove at a position corresponding to the adhesive application start / end point defined on the root of the concave groove. The semiconductor device package is characterized in that it has been expanded.