Circuit device

Priority is claimed to Japanese Patent Application Number JP2003-331635 filed on Sep. 24, 2003, the disclosure of which is incorporated herein by reference in its entirety.

1. Field of the Invention

The present invention relates to a circuit device, more particularly to a circuit device having a wiring part for forming an electric circuit therein.

2. Description of the Related Art

With reference to FIGS. 8A and 8B , a constitution of a conventional semiconductor device 100 will be described. FIG. 8A is a plan view of the semiconductor device 100 and FIG. 8B is a section view thereof (see Patent Document 1).

With reference to FIG. 8A , a land 102 made of a conductive material is formed at the central portion of the semiconductor device 100 and one end of each of a plurality of leads 101 is made close to the periphery of the land 102 . The one end of each of the plurality of leads 101 is electrically connected to a semiconductor element 104 by a thin metal wire 105 and the other end thereof is exposed from a sealing resin 103 . The sealing resin 103 has a function to seal and collectively support the semiconductor element 104 , the land 102 and the leads 101 .

[Patent Document 1]

Japanese Patent Laid-Open Hei 11 (1999)-340257

However, in the device described above, the leads 101 only function as external terminals. Thus, it was required to form conductive paths for forming an electric circuit on a surface of a mounting board on which the semiconductor device 100 is mounted. Consequently, there was a problem that a wiring structure of the mounting board is complicated.

The preferred embodiment of the present invention was made in view of the above described problem. A principal object of the preferred embodiment of the present invention is to provide a circuit device having a wiring part for forming an electric circuit therein.

A circuit device of the preferred embodiment of the present invention, which has circuit element and conductive pattern for forming an electric circuit, includes: a conductive pattern through which an electric signal passes, the electric signal being inputted/outputted between the electric circuit and the outside; and a wiring part which branches off from the conductive pattern and through which the electric signal passes, the electric signal being inputted to another portion of the electric circuit.

Furthermore, a circuit device of the preferred embodiment of the present invention, which has circuit element and conductive pattern for forming an electric circuit, includes: a first conductive pattern through which a first electric signal passes, the first electric signal being inputted/outputted between the electric circuit and the outside; a second conductive pattern through which a second electric signal passes, the second electric signal being inputted/outputted between the electric circuit and the outside and having a potential different from that of the first electric signal; a first wiring part which branches off from the first conductive pattern and through which the first electric signal passes; and a second wiring part which branches off from the second conductive pattern and through which the second electric signal passes. In the circuit device, any of the first electric signal passing through the first wiring part and the second electric signal passing through the second wiring part is inputted to the electric circuit.

According to the circuit device of the preferred embodiment of the present invention, an electric signal inputted/outputted between a built-in electric circuit and the outside can be inputted to another spot of the electric circuit through wiring formed inside the device. Therefore, a pattern structure of a mounting board can be simplified.

FIGS. 1A and 1B are a plan view and a section view showing a circuit device of a preferred embodiment of the present invention.

FIG. 2 is a plan view showing a circuit device of the preferred embodiment of the present invention.

FIG. 3 is a plan view showing a circuit device of the preferred embodiment of the present invention.

FIG. 4 is a section view showing a circuit device of the preferred embodiment of the present invention.

FIGS. 5A and 5B are a plan view and a section view showing a circuit device of the preferred embodiment of the present invention.

FIGS. 6A and 6B are a plan view and a section view showing a circuit device of the preferred embodiment of the present invention.

FIG. 7 is a section view showing a circuit device of the preferred embodiment of the present invention.

FIGS. 8A and 8B are a plan view and a section view showing a conventional circuit device.

With reference to FIGS. 1A and 1B , description will be given of a constitution of a circuit device 10 A of this embodiment. FIG. 1A is a plan view of the circuit device 10 A and FIG. 1B is a section view thereof.

With reference to FIG. 1A , the circuit device 10 A of this embodiment has a constitution in which a circuit element 13 and conductive patterns 12 , which form an electric circuit, are integrally resin-molded. Furthermore, the circuit device 10 A includes: a conductive pattern 12 A through which an electric signal passes, the electric signal being inputted/outputted between the electric circuit described above and the outside; and a wiring part 12 B which branches off from the conductive pattern 12 A and through which an electric signal passes, the electric signal being inputted to another portion of the electric circuit. Details of each component and a constitution relating thereto will be described below.

The conductive patterns 12 are made of a metal such as copper. These conductive patterns 12 are separated by a sealing resin 18 filled in a isolation trench 19 formed by etching. Here, the conductive patterns 12 mainly form a die pad, on which a semiconductor element 13 A is mounted, bonding pads, which are disposed so as to surround the die pad and to which thin metal wire is connected, and the like.

The conductive pattern 12 A is electrically connected to the semiconductor element 13 A through thin metal wire 15 . An electric signal inputted/outputted from/to the outside passes through the conductive pattern 12 A. As the electric signal described above, there is an input signal which is supplied from the outside to the electric circuit formed in the circuit device 10 A. Furthermore, as the electric signal described above, there is an output signal which is processed by the electric circuit formed in the circuit device 10 A and outputted to the outside. To be more specific, as the electric signal described above, a power supply potential, a ground potential, an output signal processed inside the device and the like are conceivable. Here, the electric circuit formed in the device means, for example, an electric circuit including the conductive patterns 12 , the thin metal wire 15 and the circuit element 13 .

The wiring part 12 B is formed of the conductive pattern 12 described above and electrically connects the conductive pattern 12 A to a conductive pattern 12 C. The conductive patterns 12 A and 12 C are disposed apart from each other while interleaving a plurality of the conductive patterns 12 therebetween. The both patterns can be electrically connected to each other by the wiring part 12 B. Here, the conductive patterns 12 positioned on the same side are connected to each other by the wiring part 12 B. However, the conductive patterns 12 positioned on different sides can be also connected to each other by the wiring part 12 B. Specifically, by connecting the conductive patterns to each other by the wiring part 12 B, an electric signal outputted from the built-in electric circuit can be outputted from the plurality of conductive patterns 12 which are disposed apart from each other. Moreover, an electric signal inputted through one of the conductive patterns 12 can be also branched off through the wiring part 12 B. Consequently, one input signal can be also supplied to a plurality of spots of the built-in electric circuit.

As the circuit element 13 , the semiconductor element 13 A is herein adopted. An active element such as, an LSI chip, a bare transistor chip, and a diode can be adopted as the circuit element 13 . Furthermore, a passive element such as a chip resistor, a chip capacitor, and an inductor can be also adopted as the circuit element 13 . The semiconductor element 13 A has its back die bonded to the die pad formed of the conductive pattern 12 . Electrodes on a surface of the semiconductor element 13 A and the bonding pads formed of the conductive patterns 12 are electrically connected to each other through the thin metal wire 15 . Moreover, the semiconductor element 13 A can be also connected thereto face down. A chip element 13 B has electrodes on its both ends, which are die bonded to the conductive patterns 12 with a brazing material such as soft solder.

The sealing resin 18 is made of thermoplastic resin formed by injection molding or thermosetting resin formed by transfer molding. The sealing resin 18 has a function to seal the whole device as well as to mechanically support the whole device. With reference to FIG. 1B , the sealing resin 18 exposes rear surface of the conductive patterns 12 to the outside and seals the circuit element 13 , the thin metal wire 15 and the conductive patterns 12 .

With reference to FIG. 1B , description will be given of a connection structure between the circuit device 10 A and a mounting board 25 . A bottom surface of the sealing resin 18 , on which the conductive patterns 12 are exposed, is covered with a resist 16 made of resin except spots where external electrodes 17 are formed. The external electrodes 17 are made of a brazing material such as soft solder and formed on the rear surface of the conductive patterns 12 . By melting the external electrodes 17 by reflow, conductive paths 26 formed on a surface of the mounting board 25 and the circuit device 10 A are electrically connected to each other. Moreover, on the surface of the mounting board 25 , a plurality of elements may be mounted other than the circuit device 10 A.

With reference to FIG. 1A , conductive paths 26 B are electrically connected to the conductive patterns 12 through the external electrodes 17 and are connected to other device on the mounting board 25 .

Here, description will be given of an advantage of having the wiring part 12 B. The conductive pattern 12 A is electrically connected to the conductive pattern 12 C through the wiring part 12 B. A conductive path 26 A at the mounting board 25 side is connected to the conductive pattern 12 C through the external electrode 17 . The conductive path 26 A and a conductive path 26 C are connected to each other through a switching part SW formed on the surface of the mounting board 25 . A conductive pattern 12 D of the circuit device 10 A and the conductive path 26 C are connected to each other through the external electrode 17 . Moreover, the conductive pattern 12 D is electrically connected to the semiconductor element 13 A through the metal thin wire 15 . Here, it is also possible to have the switching part SW built into the circuit device 10 A.

According to the constitution described above, for example, when an output signal from the semiconductor element 13 A is supplied to the conductive pattern 12 A, the output signal is fed back to the electric circuit in the circuit device 10 A through the wiring part 12 B. Specifically, a route of the feedback includes the wiring part 12 B, the conductive pattern 12 C, the external electrode 17 , the conductive path 26 A, the switching part SW, the conductive path 26 C and the conductive pattern 12 D. Accordingly, the electric signal is interrupted or conducted by the switching part SW. Thus, operations of the electric circuit built into the circuit device 10 A can be switched. Specifically, the operations of the electric circuit are changed based on whether or not the electric signal outputted to the outside through the conductive pattern 12 A is supplied to the conductive pattern 12 D.

Moreover, the conductive pattern 12 C, from which the electric signal is outputted, and the conductive pattern 12 D, through which the electric signal inputted via the switching part SW passes, are adjacent to each other. Therefore, the conductive paths 26 which connect the conductive patterns 12 C and 12 D via the switching part SW can be shortened.

As described above, by routing the wiring part 12 B in the device, a pattern structure of the conductive paths 26 at the mounting board 25 side can be simplified. Particularly, as shown in FIG. 1A , considering the case where the external electrodes are formed in a peripheral portion of the circuit device 10 A, a complicated constitution of the conductive paths 26 is required when the wiring part is formed on the mounting board 25 side. To be more specific, when wiring formed of the conductive paths 26 is formed on the mounting board 25 , the wiring has to cross the conductive paths 26 B connected to the external electrodes 17 in most cases. Therefore, such an intersecting constitution of the conductive paths 26 leads to a complicated wiring structure and costs may be increased. In the present embodiment, the wiring part 12 B is provided in the circuit device 10 A. Thus, the constitution of the conductive paths 26 can be significantly simplified.

Moreover, in the above description, the electric circuit including one semiconductor element 13 A is built into the circuit device 10 A. However, an electric circuit including a plurality of semiconductor elements or passive elements may be formed therein. Furthermore, in the above description, the output signal from the built-in electric circuit is branched off through the wiring part 12 B. However, the electric signal inputted from the outside may be branched off through the wiring part 12 B.

With reference to a plan view of FIG. 2 , a constitution of a circuit device 10 B of another embodiment will be described.

In the circuit device 10 B, conductive patterns 12 include a first and a second conductive patterns 12 A and 12 E. Through the first conductive pattern 12 A, a first electric signal inputted/outputted between the device and the outside passes. Through the second conductive pattern 12 E, a second electric signal having a potential different from that of the first electric signal passes. A basic constitution of the circuit device 10 B shown in FIG. 2 is common to that of the circuit device 10 A shown in FIG. 1A . The circuit device 10 B is different from the circuit device 10 A in having a second wiring part 12 B 2 . Such a difference will be mainly described.

The first conductive pattern 12 A is connected to a conductive pattern 12 C through a first wiring part 12 B 1 . The conductive pattern 12 C is connected to a conductive path 26 A at a mounting board side through an external electrode 17 . In such a manner, input/output of the branched off first electric signal to the outside is performed through the first wiring part 12 B 1 .

The second conductive pattern 12 E is connected to a conductive pattern 12 F through the second wiring part 12 B 2 . The second conductive pattern 12 E is a conductive pattern through which the second electric signal having a potential different from that of the first electric signal described above passes. The conductive pattern 12 F is connected to a conductive path 26 B at the mounting board side through the external electrode 17 and electrically connected to a switching part SW.

A conductive pattern 12 D is a conductive pattern to which the first or the second electric signal described above is inputted. The conductive pattern 12 D is connected to a semiconductor element 13 A through a thin metal wire 15 and is connected to a conductive path 26 C, to which an output signal of the switching part SW is supplied, through the external electrode 17 .

The switching part SW has a function to selectively supply the first electric signal, which is supplied through the conductive path 26 A, or the second electric signal, which is supplied through the conductive path 26 B, to the conductive path 26 C. Therefore, this function of the switching part SW makes it possible to change the electric signal supplied to the semiconductor element 13 A from the conductive pattern 12 D. Thus, operations of the circuit built into the circuit device 10 B can be changed.

By use of the first and second wiring parts 12 B 1 and 12 B 2 described above, the first and second electric signals can be branched off and outputted from the vicinity of the conductive pattern 12 D. Therefore, a constitution of the conductive paths 26 which connect the respective conductive patterns 12 to the switching part SW can be simplified. Furthermore, a length of the conductive paths 26 can be shortened.

According to the constitution described above, any of the first electric signal, which is outputted from the first conductive pattern 12 A, and the second electric signal, which is outputted from the second conductive pattern 12 E, can be supplied to the electric circuit in the circuit device through the conductive pattern 12 D. Therefore, the electric circuit built into the circuit device 10 B performs different operations between the case where the first electric signal is supplied and the case where the second electric signal is supplied. As a combination of the first and second electric signals, a power supply potential and a ground potential, of which potentials are significantly different from each other, can be adopted.

With reference to a plan view of FIG. 3 , a constitution of a circuit device 10 C of another embodiment will be described. The constitution of the circuit device 10 C shown in FIG. 3 is basically similar to that of the circuit device 10 B shown in FIG. 2 . The circuit device 10 C is different from the circuit device 10 B in that a switching part SW is built therein. Specifically, a switching part SW formed of a switching element such as a transistor is formed on a conductive pattern 12 . According to the constitution described above, a constitution of conductive paths 26 formed on a surface of a mounting board 25 , on which the circuit device 10 C is mounted, can be more simplified.

With reference to a section view of FIG. 4 , in a circuit device 10 D shown in FIG. 4 , a semiconductor element 13 A and a chip element 13 B are adopted as circuit elements 13 . In each of the circuit devices 10 shown in FIGS. 1 to 3 , one semiconductor element 13 A is provided. However, as described above, the electric circuit in the circuit device may include a plurality of circuit elements 13 . As a concrete connection structure of the circuit elements, electrodes of the semiconductor element 13 A, which is die bonded to the conductive pattern 12 face up, are connected to the conductive patterns 12 through thin metal wire 15 . The chip element 13 B has electrodes on its both ends, which are die bonded to the conductive patterns 12 by use of a brazing material such as soft solder.

With reference to FIGS. 5A and 5B , a constitution of a circuit device 10 E of another embodiment will be described. FIG. 5A is a plan view of the circuit device 10 E and FIG. 5B is a section view thereof.

With reference to FIG. 5A , the constitution of the circuit device 10 E is similar to that of the circuit device 10 B shown in FIG. 2 and is different therefrom in a constitution of wiring parts 12 B. Specifically, here, first and second wiring parts 12 B 1 and 12 B 2 extend below a semiconductor element 13 A. To be more specific, the first wiring part 12 B 1 extends below the semiconductor element 13 A from a first conductive pattern 12 A through which a first electric signal passes. The first conductive pattern 12 A is connected to a conductive pattern 12 C positioned in a peripheral portion of a different side. Moreover, a second conductive pattern 12 E, through which a second electric signal passes, is connected to a conductive pattern 12 F through the second wiring part 12 B 2 extending below the semiconductor element 13 A. A constitution of a switching part SW and conductive paths 26 other than those described above is similar to that shown in FIG. 2 .

With reference to FIG. 5B , a cross-sectional structure of the circuit device 10 E will be described. The conductive patterns 12 are covered with a coating resin 24 and the semiconductor element 13 A is die bonded to a surface of this coating resin 24 . According to the constitution described above, the conductive patterns 12 can be routed below a region where the circuit element 13 such as the semiconductor element 13 A is disposed. Thus, wiring density can be improved. Moreover, upper surfaces of the conductive patterns 12 in spots to be electrically connected to the circuit element 13 are exposed from the coating resin 24 . Here, upper surfaces of the conductive patterns 12 in regions to be bonding pads are exposed from the coating resin 24 .

An advantage of the constitution described above will be described. Since the wiring parts 12 B can be extended below the semiconductor element 13 A, a degree of freedom in designing the conductive patterns 12 can be improved. For example, even if the first conductive pattern 12 A and the conductive pattern 12 C are provided apart from each other, the both patterns can be connected to each other through the first wiring part 12 B 1 . Here, the first conductive pattern 12 A and the conductive pattern 12 C, which are positioned in peripheral portions opposite to each other, are connected to each other through the first wiring part 12 B 1 .

With reference to FIGS. 6A and 6B , a constitution of a circuit device 10 F of another embodiment will be described. FIG. 6A is a plan view of the circuit device 10 F and FIG. 6B is a section view thereof. A basic constitution of the circuit device 10 F shown in FIGS. 6A and 6B is similar to that of the circuit device 10 E shown in FIGS. 5A and 5B and is different therefrom in having a plurality of wiring layers. This difference will be mainly described.

With reference to FIG. 6A , a first wiring layer 20 that is an upper wiring layer is indicated by a solid line, and a second wiring layer 21 that is a lower wiring layer is indicated by a dotted line. The first wiring layer 20 , the upper layer, forms a bonding pad part, to which thin metal wire 15 is connected, and is connected to the second wiring layer 21 , the lower layer, through connection parts 23 . First and second wiring parts 12 B 1 and 12 B 2 are formed of the second wiring layer 21 , the lower layer. Moreover, it is also possible that the wiring parts 12 B are formed of the first wiring layer 20 . Other than those described above, the constitution of the circuit device 10 F is similar to that shown in FIGS. 5A and 5B .

With reference to FIG. 6B , here, the circuit device 10 F has two wiring layers including the first and second wiring layers 20 and 21 , which are laminated on each other with an insulation layer 32 interposed therebetween. The first and second wiring layers 20 and 21 are electrically connected to each other through the connection parts 23 penetrating the insulation layer 32 . Note that, as a structure of the wiring layers, a wiring structure including three layers or more is also possible.

With reference to FIG. 7 , a constitution of a circuit device 10 G of another embodiment will be described. FIG. 7 shows a section of the circuit device 10 G A basic constitution of the circuit device 10 G shown in FIG. 7 is similar to that of the circuit device 10 F shown in FIGS. 6A and 6B and is different therefrom in having a supporting board 31 . As this supporting board 31 , a well known board, including a board made of resin board such as a glass epoxy resin board, a ceramic board, a metal board can be used.