Circuit device

Priority is claimed to Japanese Patent Application Number JP2003-208094 filed on Aug. 20, 2003, the disclosure of which is incorporated herein by reference in its entirety.

1. Field of the Invention

The preferred embodiments of the present invention relate to, among other things, a circuit device having leads extending outwardly as external terminals.

2. Description of the Related Art

The following description sets forth the inventors' knowledge of the related art and problems therein and should not be construed as an admission of knowledge in the prior art.

A conventional circuit device 100 is hereby described with reference to FIG. 5 , wherein FIG. 5A is a plan view of the circuit device 100 and FIG. 5B is a cross-sectional view thereof.

In FIGS. 5A and B, a land 102 formed of conductive material is disposed in a central portion of the circuit device 100 and a plurality of leads 101 have one end thereof disposed in the periphery of the land 102 . The one end of the plurality of leads 101 is electrically connected to a semiconductor element 104 via fine metal wires 105 , whereas the other end of the leads 101 is exposed from a sealing resin 103 . The sealing resin 103 has the function of sealing and integrally supporting the semiconductor element 104 , the land 102 and the leads 101 .

The leads 101 of this circuit device 100 only have the function of electrically extending outwardly electrodes of the semiconductor element 104 and could not form rewiring sections, etc., thus making it impossible to achieve a complex electrical circuitry inside the circuit device using the leads 101 .

The preferred embodiments of the present invention were developed in view of the aforementioned and/or other problems and a main aspect thereof is to provide a semiconductor device having leads and electrical circuitry.

A circuit device according to some preferred embodiments includes: a plurality of semiconductor elements, first leads connected to bonding pads of the semiconductor elements and forming external terminals by extending outside of a package and second leads interconnecting the semiconductor elements inside the package.

A circuit device according to some preferred embodiments includes a first semiconductor element and a second semiconductor element, first leads electrically connected to the first semiconductor element or the second semiconductor element via fine metal wires and having an end thereof extending outwardly, second leads electrically connected to both the first semiconductor element and the second semiconductor element via fine metal wires for electrically connecting the first semiconductor element and the second semiconductor element.

Furthermore, a circuit device preferably includes: first leads, second leads extending in the vicinity of one of the first leads and comprising a first prominent portion projecting upwardly, third leads extending in the vicinity of another one of the first leads and comprising a second prominent portion projecting upwardly and a chip element attached to the first prominent portion and to the second prominent portion via brazing material to jump over the first leads.

Furthermore, a circuit device preferably includes: a first circuit element, first leads electrically connected to the first circuit element via first fine metal wires and having one end thereof extending outwardly, second leads connected to the first leads via second fine metal wires and a second circuit element electrically connected to the second leads.

Furthermore, a circuit device preferably includes: an island, first leads having inner leads first leads having external leads formed by providing an end thereof in a periphery of the island via inner leads and projecting another end thereof from a sealing resin and a semiconductor element disposed on the island, further comprising wiring leads extending from one region on one side of a package formed of the sealing resin inside a package and from the inside of the package to another region on the one side of the package, wherein the semiconductor element is sealed inside the package and is electrically connected to a separate circuit element via the wiring leads.

A circuit device having a plurality of islands, first leads having external leads formed by providing an end thereof in a periphery of the plurality of islands via inner leads and projecting another end thereof from a sealing resin and a plurality of semiconductor elements disposed on the plurality of islands respectively, further comprising wiring leads extending from one region on one side of a package formed of the sealing resin to a vicinity of the plurality of islands and from the vicinity of the plurality of islands to another region on the one side of the package, wherein the plurality of semiconductor elements are sealed inside the package and are electrically interconnected via the wiring leads.

FIG. 1 is a plan view illustrating a circuit device according to some embodiments of the present invention.

FIG. 2 is a plan view illustrating a circuit device according to some embodiments of the present invention.

FIGS. 3A to D are cross-sectional views illustrating a circuit device according to some embodiments of the present invention.

FIG. 4A is a plan view and FIG. 4B is a cross-sectional view illustrating a circuit device according to some embodiments of the present invention.

FIG. 5A is a plan view and FIG. 5B is a cross-sectional view illustrating a conventional circuit device.

The present invention relates to a technology implementing leads inside a package which function as wiring to achieve an SIP.

Typically, a lead frame has one or two islands, inner leads having one end thereof disposed in the vicinity of the island(s) and leads exposed outwardly from the package as exterior leads and functioning as electrodes. Semiconductor chips are respectively provided on each island and the leads are used to pass an input/output signal in electrodes of the respective semiconductor chips, thus interconnecting the semiconductor elements.

There are two types of packages which are an exception: the stacked multi-chip package comprising stacked semiconductor elements and the plain multi-chip package comprising a bridge between islands.

In the stacked-type package, the leads are provided for semiconductor elements interconnections, but they are used as external lead electrodes. On the other hand, in the plain-type package, a bridge is provided between islands for electrical interconnection. The bridge, which can be attached by an adhesive sheet, interconnects electrodes formed on side walls of mutually opposing semiconductor chips.

In FIG. 1 of the present invention, second leads having the shape of key brackets are used as wiring. Leads are used in FIG. 1 to provide connections among a plurality of semiconductor elements, whereas in FIG. 4 , they are used to provide connections among semiconductor elements and passive elements. These leads are not electrically connected to electrodes provided on a mounting board, so that they can be formed inside the package in the periphery of the island, irrespective of their shape.

Taking into consideration the drop of the second leads, the key brackets are positioned so that the second leads can be supported by the upper and lower mold. In case of using an adhesive tape, the shape does not have to be that of key brackets. With this invention, an inner lead refers to a part of a lead embedded in the package or in the sealing resin. A wiring lead refers to a lead that has the function of electrically interconnecting circuit elements. Leads as used in this invention include not only frame-like leads described in the following embodiments, but also conductive patterns, etc. formed on a mounting board.

A circuit device according to some preferred embodiments is described below with reference to FIG. 1 which is a plan view of a circuit device 10 . The circuit device 10 comprises a first semiconductor element 13 A and a second semiconductor element 13 B, first leads 11 A electrically connected to the first semiconductor element 13 A or to the second semiconductor element 13 B via fine metal wires 15 A and having an end thereof exposed outwardly, second leads 11 B electrically connected to both the first semiconductor element 13 A and the second semiconductor element 13 B via fine metal wires, thus providing electrical connections between the first and second semiconductor elements 13 A and 13 B. These elements are further described in more detail in what follows.

The first semiconductor element 13 A can be an LSI (Large Scale Integration) chip secured to a first island 12 A provided in the vicinity of the center of the circuit device 10 via an adhesive. Conductive materials such as solder or conductive paste or insulating materials made of resin can be used as adhesive, depending on the application.

The second semiconductor element 13 B can be an LSI chip similar to the first semiconductor element 13 A described above and is secured to a second island 12 B connected to the first island 12 A. The islands described above may be electrically separated.

The first island 12 A and the second island 12 B are formed by punching or etching a thin conductive foil. These two islands are linked by a connecting portion 18 . Lifting leads 19 extend from upper right and left corners of the first island 12 A disposed in an upper part of the paper to the upper right and left corners of the circuit device. Furthermore, lifting leads 19 also extend from lower right and left corners of the second island 12 B disposed in a lower part of the paper to the lower right and left corners of the circuit device. These lifting leads 19 have a function of mechanically supporting the first island 12 A and the second island 12 B during the manufacturing process of the circuit device 10 .

The first leads 11 A have an end thereof connected to the first semiconductor element 13 A or to the second semiconductor element 13 B via fine metal wires 15 A and another end thereof functioning as an exterior terminal for inputting/outputting electrical signals extends outside of a sealing resin 16 which seals this entirety.

The second leads 11 B are electrically connected to the first semiconductor element 13 A and further, with the second semiconductor element 13 B via fine metal wires 15 C. Accordingly, the first semiconductor element 13 A and the second semiconductor element 13 B are electrically connected via fine metal wires 15 C and second leads 11 B. In the paper, the first and second semiconductor elements 13 A and 13 B are aligned in a vertical direction in the vicinity of a central portion of the circuit device 10 . A plurality of second leads 11 B extend laterally in a vertical direction so as to clip the aligned first and second semiconductor devices 13 A and 13 B. Here, the second leads 11 B are shown by the hatched area. Second leads 11 B extend in the direction of alignment of the first and second semiconductor elements 13 A and 13 B so as to clip the first and second semiconductor elements 13 A and 13 B. Both ends of the second leads 11 B extend outwardly from the sealing resin 16 .

Third leads 11 C do not provide any electrical connections between the other components inside the circuit device 10 and have an end thereof extending outwardly from the sealing resin 16 . The third leads 11 C have an end thereof extending at regular intervals to the periphery of the circuit device 10 to form terminals. A plurality of third leads 11 C are provided in the area clipped by second leads 11 B in the left and right corners of the circuit device 10 in the paper.

The sealing resin 16 covers and supports the first and second semiconductor elements 13 A and respectively 13 B, leads 11 and the fine metal wires 15 . A configuration where a rear surface of leads 11 is exposed or where the sealing resin 16 covers the entirety including the rear surface of the leads 11 is also possible.

With this invention, leads 11 B are employed to provide electrical connections among semiconductor elements. Here, electrodes formed on sides opposing the first and second semiconductor elements 13 A, respectively 13 B are directly electrically connected by fine metal wires 15 B. However, it is difficult to electrically connect electrodes formed at locations other than opposing sides of the first and second semiconductor elements 13 A and respectively 13 B, using only fine metal wires 15 . The use of the second leads 11 B can help solve this issue. Electrodes formed on a lateral periphery of the first semiconductor element 13 A are electrically connected to the second leads 11 B via fine metal wires 15 C. The second leads 11 B extend vertically on the paper from the lateral periphery of the first semiconductor element 13 A to the lateral periphery of the second semiconductor element 13 B. The second semiconductor element 13 B and the second leads 11 B are electrically connected via fine metal wires 15 C. Electrodes of the first semiconductor element 13 A at locations other than the area adjacent the second semiconductor element 13 B and electrodes of the second semiconductor element 13 B at locations other than the area adjacent the first semiconductor element 13 A are electrically connected via the second leads 11 B.

Further wiring can be configured by connecting leads 11 via fine metal wires 15 . Next, a configuration is described where electrode E 1 of the first semiconductor element 13 A and electrode E 2 of the second semiconductor element 13 B are electrically connected via fine metal wires 15 and leads 11 . Here, electrode E 1 is an electrode formed in the first semiconductor element 13 A in a peripheral portion opposing an area adjacent the second semiconductor element 13 B. Electrode E 2 is a electrode formed in the second semiconductor element 13 B in a peripheral portion opposing an area adjacent the first semiconductor element 13 A. Electrode E 1 is connected to a first lead 11 A 1 via a fine metal wire 15 A and the first lead 11 A 1 is connected to a second lead 11 B 1 in the upper paper via a fine metal wire 15 D. The second leads 11 B 1 extend vertically in the paper in a right lateral direction of the first and second semiconductor elements 13 A and 13 B. Then, the electrode E 2 is electrically connected to the lower paper of the second lead 11 B 1 via a fine metal wire 15 E.

Next, the electrical coupling structure in the vicinity of the first lead 11 A 1 is described. First lead 11 A 1 has an end thereof extending out of the sealing resin 16 forming the package outline to form an exterior terminal. Another end of the first lead 11 A 1 extends to the vicinity of the first semiconductor element 13 A which functions as a circuit element and is electrically connected to the bonding pads of the first semiconductor element 13 A via the fine metal wires 15 A. The first lead 11 A 1 and the second lead 11 B 1 are electrically connected via a fine metal wire 15 D. Here, the fine metal wires 15 D rise above a plurality of leads and electrically connect leads of the same type. The use of such fine metal wire 15 D enables provision of electrical connections among leads at random locations which renders possible the increase of the degree of freedom in wiring using leads. First lead 11 A 1 has an end thereof extending outwardly and functioning as an external terminal and, at the same time, by providing connections via fine metal wires 15 D, they also function as a part of a wiring pattern embedded in the package.

In the circuit device 10 shown in FIG. 1 , exterior terminals formed by one end of the first leads 11 A, second leads 11 B and third leads 11 C extend outwardly from 4 peripheral portions of the sealing resin 16 at regular intervals. These exterior terminals are secured to the mounting board to thus enable mounting of the circuit device 10 and stabilization in mounting the circuit device 10 .

Another embodiment of a circuit device 10 is next described with reference to FIG. 2 . The fundamental configuration of the circuit device in FIG. 2 is similar to that of the circuit device described with reference to FIG. 1 , accordingly, only differences thereinbetween are described in what follows.

The third semiconductor element 13 C is preferably a bare transistor chip, etc. and is secured to a third island 12 C disposed somewhere halfway the second leads 11 B. The semiconductor element 13 C is directly connected to either a first semiconductor element 13 A or to a second semiconductor element 13 B via fine metal wires 15 . Here, the semiconductor element 13 C may be electrically connected to the first or second leads 11 A or respectively 11 B via fine metal wires 15 . Two third islands 12 C extend from the second leads 11 B so as to approach the connecting portion 18 .

The fourth semiconductor element 13 D is preferably an LSI chip, etc. and is secured to a surface of a second semiconductor element 13 B. A stacked structure is thus obtained by a second semiconductor element 13 B and a forth semiconductor element 13 D secured to the second semiconductor element 13 B. The fourth semiconductor element 13 D is electrically connected to the first leads 11 A and the second leads 11 B, or with other circuit elements via fine metal wires 15 .

The second leads 11 B are embedded in the sealing resin that forms the package. The main role of the second leads 11 B is to electrically connect circuit elements embedded in the package and therefore, they can be embedded in the package. With this configuration wherein third leads 11 C have been omitted, a circuit device with a simplified structure can be achieved.

Support tape 25 has the role of supporting the second leads 11 B. Since the second leads 11 B are mechanically separated, a mechanism is needed to mechanically support each of these leads until the process of forming the sealing resin. Displacement of the second leads 11 B can be prevented during the manufacturing process by securing the second leads 11 B using an adhesion tape 25 which is applied to a surface or rear surface of the second leads 11 B. Concretely, the support tape 25 has a function of securing the second leads 11 B to the first leads 11 A or to other leads. In the process of resin sealing, an adhesive sheet formed of resin, etc. may be attached to the rear surface of the leads to prevent the resin from wrapping around the rear surface of the leads.

Next, a detailed description is given with reference to FIG. 3B of a prominent portion 17 provided on a second lead 11 B at a location where fine metal wires 15 C are formed. FIG. 3 is a view of a region A shown in FIG. 1 , taken in an X 1 direction. The prominent portion 17 is formed of an inclined portion 20 extending obliquely upward towards the second leads 11 B extending in a horizontal direction and a planar portion 21 extending in a horizontal direction from the inclined portion 20 . With this configuration, it is possible to place the planar portion 21 at a position above the other second leads 11 B. The planar portion 21 which continues via the inclined portion 20 improves resistance of the prominent portion 17 and prevents dispersion of ultrasonic energy at the time of wire bonding. The prominent portion 17 can be provided on the second leads 11 B or on the first leads 11 A.

The coupling structure of the second leads 11 B and semiconductor element 13 is next described with reference to FIG. 3B which is a view taken in the X 2 direction of the region A shown in FIG. 1 . Fine metal wires 15 C jump over at least a lead 11 and are connected to the prominent portion 17 provided on the second leads 11 B. This structure enables the heightening of the position of the entire fine metal wires 15 C to thus increase the clearance between the fine metal wires 15 C and the leads 11 (in particular, the second leads 11 B located nearest to the prominent portion 17 ). Accordingly, even in case the fine metal wires 15 C deform downwardly due to their own weight or to the pressure applied thereto during the resin sealing process, the second leads 11 B and the fine metal wires 15 C extending between the prominent portion 17 and the semiconductor element 13 are prevented from coming into contact.

In FIG. 3C , the second lead 11 B abutting to the island 12 is connected to the semiconductor element 13 secured on the island 12 via fine metal wires 15 C. The semiconductor element 13 and the second nearest lead 11 can be connected without providing a prominent portion 17 in the lead 11 B at the location where fine metal wires 15 are connected. This represents the common wire-bonding process.

Prominent portions 17 provided halfway leads 11 are connected by fine metal wires 15 C jumping over a plurality of leads 11 , as shown in FIG. 3D . That means that one prominent portion 17 and the fine metal wire 15 C are connected by ball bonding, whereas the other prominent portion 17 and the fine metal wire are connected by wedge bonding.

Another embodiment of a structure of a circuit device 30 is described with reference to FIG. 4 . FIG. 4A is a plan view of the circuit device 30 and FIG. 4B is a cross-sectional view of a region C shown in FIG. 4A taken along the X 4 direction. The fundamental structure of a circuit device 30 shown here is same as that of the device described with reference to FIG. 1 and the difference therebetween is in the coupling structure of a chip element 44 .

Here, the circuit device 30 includes: first leads 31 A, second leads 31 B extending in the vicinity of one of the first leads 31 A and comprising a first prominent portion 45 A projecting upwardly, third leads 31 C extending in the vicinity of other first leads 31 A and comprising a second prominent portion 45 B projecting upwardly and provided in the vicinity of the first prominent portion 45 A, and a chip element 44 attached to the first prominent portion 45 and to the second prominent portion 45 B via brazing material to jump over the first leads 31 A. Here, the chip element 44 can be a chip resistor or a chip capacitor and can be electrically connected to the leads via brazing material 46 , such as solder, etc.

Electrodes provided at both ends of the chip element 44 are connected to the leads 31 via brazing material 46 as shown in FIG. 4B . The chip element 44 is mounted so as to act as a bridge between the first prominent portion 45 A of the second lead 31 B and the second prominent portion 45 B of the third lead 31 C. Accordingly, by forming the prominent portion 45 , the position of the chip element 44 becomes higher relative to the leads 31 thus enabling prevention of shorts between the other leads and the brazing material 46 used in connecting the chip element 44 .

With reference to the same figure, the chip element 44 is connected to second and third leads 31 B and respectively 31 C so as to jump over the first leads 31 A. This disposition of the chip element 44 allows for the adoption of chip elements which can be relatively large-scale chip capacitors, etc. The second and third leads 31 B and 31 C can be formed in accordance with the size of the chip element 44 and so as to jump over a plurality of first leads 31 A. Compared to leads 31 at other locations, the width of the prominent portion 45 is large so that leaks of the brazing material 46 are prevented.

The above description concerns packages which have leads, but the described structure can be applied to other types of packages without limitation. Such other types of packages can include QFP (Quad Flat Package), QFN (Quad Flat Non-leaded Package), packages using an interposer of glass epoxy substrate, etc.

Second leads which extend in the alignment direction of a plurality of semiconductor elements and the fine metal wires provide electrical connections among semiconductor elements. It is thus possible to achieve a relatively complex wiring structure by employing leads. In case a design modification of the electrical circuit is required inside the circuit device, this modification can be implemented by modifying locations where fine metal wires are formed or by increasing/reducing the number of fine metal wires, without performing any modification to the lead pattern.

With this invention, fine metal wires connecting the semiconductor elements and the leads are also connected to a prominent portion projecting upwardly from the leads. It is therefore possible to place the entire fine metal wires at a position above the leads and even in case the fine metal wires are long, unnecessary contact between the fine metal wires and the leads can be prevented. It is also possible to secure the chip element to the prominent portion via brazing material. The structure described above prevents any shorts between the brazing material and the other leads.