JPH10284691A - Semiconductor device and noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the increase of a delay time and, at the same time, reduce a component cost and an assembly and mounting cost in the manufacture of an electronic apparatus by a method, wherein a spiral-shaped filter is built in a semiconductor device itself. SOLUTION: A distributed constant type low-pass filter is composed of a distributed capacitance 16, formed between a semiconductor substrate 1 and a 1st metal wiring 3 and the inductance of the 1st metal wiring 3 formed into a spiral shape. If, for instance, a spiral is formed around a pad of 60 μm-square, the noises of an electronic apparatus used in a GHz frequency band can be effectively removed. Further, the increase in a delay time can be avoided and, a component cost and an assembly and mounting costs in the manufacture of the electronic apparatus can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a noise filter and a noise filter.

[0002]

2. Description of the Related Art With the recent increase in the speed of electronic devices, measures against noise in internal circuits have become indispensable, and the demand for noise filters used in internal circuits is increasing year by year. In order to reduce the total cost of products, low cost and high performance noise filters are required from the market. Recently, a noise filter using a semiconductor process that can be mass-produced at low cost has been attracting attention.

A conventional noise filter utilizing a semiconductor process is disclosed in Japanese Patent Application Laid-Open No. Hei 6-77711. FIG. 5 is a sectional view of a conventional noise filter, and FIG.
FIG. 1 shows an equivalent circuit of a conventional noise filter.

In FIG. 5, reference numeral 1 denotes a semiconductor substrate, 2 denotes an insulating film, 3 denotes a first metal wiring, 5 denotes a second metal wiring, and 8 denotes an extraction electrode of the first metal wiring 3.

In a conventional noise filter process, a first metal wiring 3 is formed in a spiral shape on a semiconductor substrate 1, and then an insulating film 2 is formed on the surface of the first metal wiring 3. A second metal wiring 5 is formed in a spiral shape on the insulating film 2 and the first metal wiring 3 is formed.
The extraction electrode 8 is formed at the end of the substrate.

After the above-described steps, bonding is performed to the extraction electrodes 8 at both ends of the second metal wiring 5 and at the end of the first metal wiring 3.

In FIG. 6, 3 is a first metal wiring, 5 is a second metal wiring, 8 is an extraction electrode of the first metal wiring 3, 15
Is a distributed capacitance formed between the first metal wiring 3 and the second metal wiring 5, and 20 is an inductance owned by the first metal wiring 3 and the second metal wiring 5.

The first metal wiring 3 and the second metal wiring 5 formed in a spiral shape have a predetermined inductance 20, and the first metal wiring 3 is formed by the insulating film 2 of FIG. 5 acting as a dielectric. Since the distributed capacitance 15 is formed between the third metal wiring 3 and the second metal wiring 5, it can be used as a distributed constant low-pass filter based on inductance and distributed capacitance.

[0009]

In a conventional semiconductor device, a noise filter is not formed in a process step.
By taking a logical product using a delay inverter in the internal logic circuit, noise is prevented from propagating inside, but there is a problem that the delay time increases.

[0010] Further, the noise filter using the conventional semiconductor process is a single piece of the noise filter itself, so that the cost of parts for manufacturing electronic equipment products is reduced.
There has been a problem that assembly and mounting costs increase.

Further, the noise filter of the conventional semiconductor process has a two-layer structure process of metal wiring, and there is a problem that the weight of the process cost is increasing with the price reduction of the noise filter alone. Was.

Therefore, the present invention has a built-in noise filter in the semiconductor device itself to avoid an increase in delay time, and to reduce the cost of parts in manufacturing electronic equipment products.
An object of the present invention is to reduce assembly and mounting costs.

Another object of the present invention is to make it possible to reduce the manufacturing cost by simplifying the conventional process steps to form a one-layer structure of metal wiring.

[0014]

In a semiconductor device according to a first aspect of the present invention, in each of the pads, for the signal wiring from the pad to the internal circuit, the signal wiring is arranged at least several times around the pad. The semiconductor chip itself is provided with a spiral noise filter by being laid out in a spiral shape and then routed to the internal circuit through an electrostatic protection circuit.

According to a second aspect of the present invention, there is provided the semiconductor device according to the first aspect, wherein the semiconductor substrate (or the well) is partially formed on a surface of a semiconductor substrate (or a well formed on the surface of the substrate). A region of a conductive type different from the conductive type (region 1) is formed, and a part of a spiral noise filter forming portion of the signal wiring is in contact with the region 1.

According to a third aspect of the present invention, in the noise filter, a first metal wiring is formed in a spiral shape on a semiconductor substrate with a first insulating film interposed therebetween, and the first metal wiring operates as a signal line. The semiconductor substrate operates as a ground line.

According to a fourth aspect of the present invention, there is provided the noise filter according to the third aspect, wherein the semiconductor substrate (or the well) is partially provided on a surface of a semiconductor substrate (or a well formed on the surface of the substrate). A region of a conductivity type different from the conductivity type (region 2) is formed, and a part of the first metal wiring is in direct contact with the region 2.

According to a fifth aspect of the present invention, in the noise filter according to the third aspect, a part of a first metal wiring (different from a signal line) forming a pad of a ground line is directly connected to the semiconductor. It is characterized by being in contact with a substrate.

A noise filter according to a sixth aspect of the present invention is the noise filter according to the fifth aspect, wherein the semiconductor substrate (or the well) is partially formed on a surface of a semiconductor substrate (or a well formed on the surface of the substrate). A region of a conductivity type different from the first conductivity type is formed in a spiral shape while facing the first metal wire (signal line) (referred to as region 3), and a first metal wire forming a pad of a ground line is formed. (Particularly different from the signal line) is brought into contact with a part of the region 3, and the region 3 is operated as a ground line.

[0020]

By incorporating a noise filter in a semiconductor device, it is possible to prevent propagation of noise to internal circuits without increasing delay time.

The noise filter in which the metal wiring is composed of one layer uses a semiconductor substrate as a ground line, so that the cost can be reduced as compared with the related art.

Further, by forming a protection diode against electrostatic breakdown between the signal line and the semiconductor substrate (ground line), the resistance against static electricity can be increased as compared with a noise filter without a diode.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a view showing the vicinity of a pad of a semiconductor device according to the first aspect of the present invention.

In FIG. 1A, 40 is a pad, 41 is an electrostatic protection circuit, 42 is an internal circuit, and 43 is a spiral noise filter. Here, it is assumed that 43 is formed of the first metal wiring.

FIG. 1B shows an equivalent circuit of the noise filter. 3 is a first metal wiring, 20 is a first metal wiring 3
Is a distributed capacitance (MOS capacitance) formed between the first metal wiring 3 and the semiconductor substrate 1 (or a well formed on the substrate surface), and 1 is an inductance formed on the semiconductor substrate (or the substrate surface). Wells) and 8 are pad extraction electrodes.

As is apparent from FIG. 1B, a distributed capacitor 16 formed between the semiconductor substrate 1 (or a well formed on the substrate surface) and the first metal wiring 3 and a spirally formed distributed capacitor 16 are formed. The inductance possessed by the first metal wiring 3 forms a distributed constant low-pass filter.

For example, when a spiral is formed around a pad of 60 μm square, the inductance value of the spiral is about 1.25 nH, and the capacitance is about 0.2 pF when the interlayer film thickness with the semiconductor substrate is 0.8 μm. Become.

In this case, the resonance frequency is about 10 GHz, and it is possible to effectively remove noise particularly from electronic equipment using a frequency in the GHz band.

Also, without increasing the delay time,
In addition, it is possible to reduce the cost of parts and the cost of assembling and mounting when manufacturing electronic equipment products.

(Embodiment 2) FIG. 2 is a sectional view of a noise filter provided in a semiconductor device according to the second aspect of the present invention.

In FIG. 2A, reference numeral 1 denotes a semiconductor substrate;
Is a first insulating film, 3 is a first metal wiring, 8 is a pad lead electrode, 10 is a conductive paste, 12 is a lead frame, and 25 is a conductive layer of the semiconductor substrate 1 (or a well formed on the substrate surface). Area of conductive type different from type,
7 is a second insulating film. Here, the semiconductor substrate 1 (or a well formed on the substrate surface) is described as p-type, and 25 is described as n-type.

In the process step, a first insulating film 6 is formed on the semiconductor substrate 1 (or the well), and then a part of the first insulating film 6 is removed by etching. Next, the diffusion or ion
A region 25 of a conductivity type different from the conductivity type of the semiconductor substrate 1 (or the well) is formed by implantation. Next, a first metal wiring 3 is formed in a spiral shape on the first insulating film 6, and a part of the first metal wiring 3 and a contact 25 are made. Then, C
A passivation film (second insulating film 7) is formed by deposition of VD or the like, and the passivation film is removed by etching only at the extraction electrodes 8 at both ends of the first metal wiring 3, and the process is completed.

FIG. 2B shows an equivalent circuit of the noise filter. FIG. 1 (b) except that a pn junction diode 26 formed at the junction surface between the semiconductor substrate 1 (or the well) and a region 25 of a conductivity type different from the conductivity type of the semiconductor substrate 1 (or the well) is added. Is the same as

As apparent from the equivalent circuit diagram, according to the second embodiment, a protection diode against electrostatic breakdown is formed in addition to the low-pass filter.

With the above-described structure, not only can the noise immunity be improved, but also the electrostatic immunity of the semiconductor device can be further increased.

(Embodiment 3) FIG. 3 is a sectional view of a noise filter according to the third aspect of the present invention.

In FIG. 3, 1 is a semiconductor substrate, and 6 is a first substrate.
Insulating film, 3 is the first metal wiring, 8 is the first metal wiring 3
, A conductive paste; 12, a lead frame; and 7, a second insulating film.

In the process step, a first insulating film 6 is formed on the semiconductor substrate 1, and then a first insulating film 6 is formed on the first insulating film 6.
Is formed in a spiral shape, a passivation film (second insulating film 7) is formed by deposition or the like by CVD, and the passivation film is etched only at the extraction electrodes 8 at both ends of the first metal wiring 3. To end.

After the completion of the process steps, the extraction electrodes 8 at both ends of the first metal wiring 3 are bonded. In this embodiment, the lead frame 12 where the semiconductor substrate 1 is bonded with the conductive paste 10 plays the role of a ground potential.

FIG. 1B shows an equivalent circuit of the noise filter.
Is the same as

The noise filter according to the present invention can be reduced in cost as compared with the conventional one because the metal wiring is constituted by one layer.

Also, since the noise filter is a single product, the resonance frequency can be selected by selecting the film thickness and film type of the first insulating film 6 (the product lineup is abundant). There are benefits.

(Embodiment 4) FIG. 4 is a sectional view of a noise filter according to the fourth aspect of the present invention.

In FIG. 4, reference numeral 25 denotes a region of a conductivity type different from the conductivity type of the semiconductor substrate 1 (or a well formed on the substrate surface), and the other portions are the same as those of FIG.
Here, the semiconductor substrate 1 (or the well) is p-type,
25 is described as n-type.

In the process step, a first insulating film 6 is formed on the semiconductor substrate 1 (or the well), and then a part of the first insulating film 6 is removed by etching. Next, the diffusion or ion
A region 25 of a conductivity type different from the conductivity type of the semiconductor substrate 1 (or the well) is formed by implantation. Next, the first metal wiring 3 is formed in a spiral shape on the first insulating film 6 and the first metal wiring 3 is formed.
Contact with a part of. After that, a passivation film (second insulating film 7) is formed by deposition or the like by CVD, and the passivation film is removed by etching only at the extraction electrodes 8 at both ends of the first metal wiring 3, and the process is completed.

After the completion of the process, bonding is performed to the extraction electrodes 8 at both ends of the first metal wiring 3. In this embodiment, the lead frame 12 where the semiconductor substrate 1 is bonded with the conductive paste 10 plays the role of a ground potential.

FIG. 2B shows an equivalent circuit of the noise filter.
Is the same as

Thus, according to the fourth embodiment, the same distributed constant type low-pass filter as that of the third embodiment is formed, and a protection diode against electrostatic breakdown is also formed, so that the noise resistance of the noise filter is improved.

Further, a first insulating film 6 for insulating the semiconductor substrate 1 and the first metal wiring 3 to have a protection diode.
Can be made smaller than when there is no protection diode, so that it is possible to make a noise filter with a higher capacity than when there is no protection diode, and to make the chip size smaller than when there is no protection diode. Can be smaller.

According to a fifth aspect of the present invention, there is provided a structure in which a part of a first metal wiring (different from a signal line) forming a pad of a ground line directly contacts the semiconductor substrate. Is also good.

According to a sixth aspect of the present invention, a conductive type different from the conductive type of the semiconductor substrate (or the well) is formed on a part of the surface of the semiconductor substrate (or the well formed on the substrate surface). A region is formed in a spiral shape (referred to as a region 3) while being opposed to the first metal wiring (signal line), and one of the first metal wirings (different from the signal line) forming pads of the ground line is formed. The structure may be such that the portion is brought into contact with a part of the region 3 and the region 3 is operated as a ground line.

In this case, by increasing the impurity concentration of the region 3, the ground line resistance can be reduced, and the ground line is formed in a spiral shape.

[0053]

By incorporating a noise filter in a semiconductor device, it is possible to prevent noise from propagating to an internal circuit without increasing the delay time.

The noise filter in which the metal wiring is constituted by one layer uses the semiconductor substrate as the ground line, so that the cost can be reduced as compared with the conventional one.

Further, by forming a protection diode between the signal line and the semiconductor substrate (ground line) against electrostatic destruction, it is possible to increase the resistance to static electricity as compared with a noise filter without a diode.

When a protection diode is provided, a noise filter having a higher capacity can be produced than when the protection diode is not provided, and the chip size can be made smaller than when the protection diode is not provided.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a noise filter included in a semiconductor device according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a noise filter according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of a noise filter according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional noise filter.

FIG. 6 is a diagram of an equivalent circuit of a conventional noise filter.

[Explanation of symbols]

1. . . . Semiconductor substrate 2. . . . 2. Insulating film . . . First metal wiring 5. . . . Second metal wiring 6. . . . First insulating film 7. . . . Second insulating film 8. . . . Extraction electrode 10. . . . Conductive paste 12. . . . Lead frame 15. . . . 15. Distributed capacitance formed between the first metal wiring and the second metal wiring . . . 20. Distributed capacitance formed between the first metal wiring and the semiconductor substrate . . . Inductance owned by the first metal wiring and the second metal wiring 25. . . . 26. A region of a conductivity type different from the conductivity type of the semiconductor substrate . . . pn junction diode 40 pad 41 electrostatic protection circuit 42 internal circuit 43 spiral noise filter

Claims (6)

[Claims] In each pad, for a signal wiring from the pad to an internal circuit, the signal wiring is laid out in a spiral shape at least several times around the pad, and then passed through an electrostatic protection circuit to the internal wiring. A semiconductor device in which a semiconductor chip itself is provided with a spiral noise filter by being routed to a circuit. 2. The semiconductor device according to claim 1, wherein a part of a surface of the semiconductor substrate (or a well formed on the surface of the substrate) is of a conductive type different from the conductive type of the semiconductor substrate (or the well). (Referred to as a region 1), wherein a part of the signal wiring where a spiral noise filter is formed is in contact with the region 1. 3. A first insulating film on a semiconductor substrate with a first insulating film interposed therebetween.
Wherein the first metal wiring operates as a signal line, and the semiconductor substrate operates as a ground line. 4. The noise filter according to claim 3, wherein a part of the surface of the semiconductor substrate (or a well formed on the surface of the substrate) is of a conductive type different from the conductive type of the semiconductor substrate (or the well). (Area 2
), And a part of the first metal wiring is in direct contact with the region 2. 5. The noise filter according to claim 3, wherein a part of a first metal wiring (different from a signal line) forming a pad of a ground line is in direct contact with said semiconductor substrate. Noise filter to do. 6. The noise filter according to claim 5, wherein a conductive type region different from a conductive type of said semiconductor substrate (or said well) is provided on a part of a surface of said semiconductor substrate (or a well formed on the substrate surface). Is formed in a spiral shape (referred to as a region 3) while facing the first metal wiring (signal line), and a part of the first metal wiring (different from the signal line) forming the pad of the ground line And a part of the region 3 is contacted, and the region 3 is operated as a ground line.