WO2007129384A1

WO2007129384A1 - Lc noise filter

Info

Publication number: WO2007129384A1
Application number: PCT/JP2006/309087
Authority: WO
Inventors: Takeshi Ikeda; Hiroshi Miyagi; Kouichi Ikeda
Original assignee: Niigata Seimitsu Co., Ltd.
Priority date: 2006-05-01
Filing date: 2006-05-01
Publication date: 2007-11-15

Abstract

Provided is an LC noise filter by which breakage due to static electricity or the like is prevented by increasing the withstand voltage. The LC noise filter is provided with a spiral electrode (130) formed on a semiconductor substrate (110); a spiral electrode (120), which is formed on the semiconductor substrate (110), at least partly overlaps the spiral electrode (130) by maintaining a prescribed distance from the spiral electrode, and has the overlapped portion arranged further from the semiconductor substrate (110) than the spiral electrode (130); and diodes (112D, 114D, 116D) which are connected to the end sections of the spiral electrodes (130, 120) and are formed as an input protection circuit composed of a semiconductor element formed on the semiconductor substrate (110).

Description

The present invention relates to an LC noise filter that removes noise in an electronic device.

Background art

Conventionally, a distributed constant type noise filter having double spiral electrodes formed on a semiconductor substrate is known (for example, see Patent Document 1). By adopting a distributed constant configuration, it is possible to remove noise included in a relatively wide frequency range. Patent Document 1: Japanese Patent No. 3029929 (Page 2-3, Figure 1-6)

Disclosure of the invention

Problems to be solved by the invention

[0003] By the way, the noise filter disclosed in Patent Document 1 is formed on an insulating substrate (semiconductor substrate) using a semiconductor manufacturing technique, so an instantaneously excessive voltage such as static electricity with a low withstand voltage is applied. There is a problem that the insulating layer between the double spiral electrode may be destroyed. In order to avoid such problems, it is conceivable to insert an anti-static element between the external input terminal and the noise filter. However, the increase in the number of parts and the associated assembly man-hours. This will lead to an increase in the process complexity and cost.

[0004] The present invention was created in view of these points, and an object of the present invention is to provide an LC noise filter capable of preventing breakdown due to static electricity or the like by increasing the withstand voltage. Means to solve

In order to solve the above-described problem, an LC noise filter of the present invention includes a first inductor conductor formed on a semiconductor substrate, and at least a part of the first inductor conductor formed on the semiconductor substrate. And a second inductor conductor disposed at a position farther from the semiconductor substrate than the first inductor conductor. And an input protection circuit made of a semiconductor element connected to the ends of the first and second inductor conductors and formed on the semiconductor substrate. By providing an input protection circuit at the end of the inductor conductor, the breakdown voltage can be increased and breakdown due to static electricity or the like can be prevented.

[0006] Further, it is desirable that the second inductor conductor described above is used for a signal line through which signals are input and output, and that one end of the first inductor conductor is grounded. When the first and second inductor conductors are formed using a two-layer metal structure, the thickness of the second inductor conductor, which is the upper layer, is generally thicker depending on the manufacturing process. By using the second inductor conductor as the signal line, the resistance of the signal line can be lowered.

[0007] In addition, it is preferable that the above-described second inductor conductor is provided with an input protection circuit at each of both ends, and the first inductor conductor is provided with an input protection circuit at an end that is grounded. . As a result, a distributed constant type LC noise filter can be realized, and a noise component included in a signal input to the second inductor conductor can be removed.

[0008] Further, it is desirable that the above-described first inductor conductor is provided with an input protection circuit at the other end as well as the end that is grounded. As a result, the breakdown voltage of the LC noise filter can be further increased.

[0009] Further, the input protection circuit described above is preferably a diode configured by a PN junction formed on a semiconductor substrate. As a result, when an excessive voltage is applied to at least one of the first and second inductor conductors, a current can flow through the semiconductor substrate, and the first and second inductor conductors caused by the excessive voltage can flow. Power to prevent dielectric breakdown S

[0010] Further, it is desirable that the end portion of the first inductor conductor described above that is grounded is an inner peripheral end portion. As a result, there is no need to form connection pads on the outer periphery of the first inductor conductor. Therefore, when the size of the semiconductor substrate is constant, the first inductor conductor and the first inductor conductor are formed so as to overlap therewith. The diameter of the outermost peripheral portion of the second inductor conductor can be increased, and a large inductance can be secured.

[0011] Further, it is desirable to adjust the frequency characteristics by varying the overlapping area of the first and second inductor conductors described above. This keeps the LC noise filter area unchanged The characteristics can be changed.

[0012] In addition, pads are connected to both ends of the second inductor conductor and one end of the first inductor conductor described above, and knocking is performed by wafer level CSP (Chip Scale Package). It is desirable. This makes it possible to reduce the size of the chip component when the LC noise filter is formed as a chip component.

[0013] In addition, it is desirable that the first and second inductor conductors and the input protection circuit are formed on a common semiconductor substrate. As a result, it is possible to realize a small chip component incorporating a large number of LC noise filters.

[0014] Further, the second inductor conductor described above is used for a signal line through which signals are input and output, and the first inductor conductor is grounded at one end, and a plurality of first inductor conductors corresponding to a plurality of sets. It is desirable that one end of each is connected to each other. As a result, the number of terminals for external connection can be reduced in chip components incorporating a plurality of LC noise filters, and the distance between these terminals can be secured to the maximum. In addition, when it is necessary to ensure a certain distance between the terminals for external connection, it is possible to reduce the size of the chip component. Brief Description of Drawings

FIG. 1 is a plan view of an LC noise filter according to an embodiment.

FIG. 2 is a cross-sectional view of a circumferential portion of a spiral electrode.

FIG. 3 is a sectional view of the pad.

FIG. 4 is a cross-sectional view of the pad.

FIG. 5 is an equivalent circuit diagram of the LC noise filter.

FIG. 6 is an explanatory diagram of an outline of a method for manufacturing an LC noise filter.

FIG. 7 is an explanatory diagram outlining the manufacturing method of an LC noise filter.

FIG. 8 is a cross-sectional view of the LC noise filter shown in FIG.

FIG. 9 is a cross-sectional view of a wafer level CSP corresponding to an LC noise filter.

FIG. 10 is a diagram showing a wafer level CSP process.

FIG. 11 is a diagram showing a wafer level CSP process.

FIG. 12 is a diagram showing a wafer level CSP process.

FIG. 13 is a diagram showing a wafer level CSP process. FIG. 14 is a diagram showing a specific example of dicing.

Explanation of symbols

[0016] 100 LC noise filter

110 Semiconductor substrate

112, 114, 116 N + region

112D, 114D, 116D diode

120, 130 Snoylanore electrode

122, 124, 132 nodes

122A input terminal

124A output terminal

132A Grounding terminal

140 capacitors

200, 202 Insulation layer

J 10 iJBM underbump metal)

320 Cu rewiring

330 Cu post

340 Handa Bonole

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an LC noise filter according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

FIG. 1 is a plan view of an LC noise filter according to an embodiment. As shown in FIG. 1, the LC noise filter 100 of this embodiment includes spiral electrodes 120 and 130 as double inductor conductors formed on the surface of a semiconductor substrate 110 which is a P-type silicon substrate, and a semiconductor substrate 110. Pads 122 and 124 as input / output terminals formed near both ends of one spiral electrode 120 on the far side (upper layer) and the inner peripheral end of the other spiral electrode 130 on the side closer to the semiconductor substrate 110 (lower layer) A pad 132 as a grounding terminal formed in the vicinity and an N ⁺ region 112, 114, 116 formed at the position of the semiconductor substrate 110 facing these three pads 122, 124, 132 are provided. . Each of the double spiral electrodes 120, 130 has a predetermined number of turns and has substantially the same shape. For example, these spiral electrodes 120 and 130 are formed using a two-layer metal wiring using gold or aluminum. In the case of a two-layer metal structure, the force due to the manufacturing process The upper spiral electrode 120 is thicker than the lower spiral electrode 130. In this embodiment, the upper spiral electrode 120 with a large film thickness is used for a signal line, and the lower spiral electrode 130 with a small film thickness is used for grounding (for the electrical connection state). Will be described later).

FIG. 2 is a cross-sectional view of the surrounding portions of the spiral electrodes 120 and 130. A spiral electrode 130 is formed on the surface of the semiconductor substrate 110 with an insulating layer 200 interposed therebetween, and a spiral electrode 120 is formed thereon with an insulating layer 202 interposed therebetween. For the insulating layers 200 and 202, for example, SiO 2 is used. In the example shown in FIGS. 1 and 2, spiral power is used.

2

A force that makes the shapes of the poles 120 and 130 substantially the same may be shifted from each other with at least a part of the force overlapping. Alternatively, the lengths in the circumferential direction may be different (specifically, the length near the semiconductor substrate 110 and the length on the outer peripheral end side of the spiral electrode 130 may be shortened). That is, in the LC noise filter 100 described above, the spiral electrode 130 as the first inductor conductor formed on the semiconductor substrate 110 and the semiconductor substrate 110 are formed, and at least a part of the spiral electrode 130 and the insulating layer 20 are formed. 2 and a spiral electrode 120 as a second inductor conductor that is disposed at a position farther from the semiconductor substrate 110 than the overlapped partial force spiral electrode 130. I'll do it. In addition, when the frequency of the signal input / output to / from the LC noise finisher 100 of this embodiment is high, the number of turns of the spiral electrodes 120 and 130 may be 1 or less.

[0021] Pads 122 and 124 formed integrally with the spiral electrode 120 in the vicinity of both ends of one spiral electrode 120 are for inputting and outputting signals to be subjected to noise removal. For example, the pad 122 provided on the inner peripheral side is used as the input terminal 122A, and the pad 124 provided on the outer peripheral side is used as the output terminal 124A. Further, diodes 112D and 114D formed by a PN junction between the semiconductor substrate 110 and N ⁺ regions 112 and 114 formed in a part of the semiconductor substrate 110 are arranged immediately below these pads 122 and 124. . FIG. 3 is a cross-sectional view of pad 122. Note that the cross-sectional structure of the pad 124 is the same, and a detailed description thereof is omitted. An N ⁺ region 112 is formed in the vicinity of the surface of the P-type semiconductor substrate 110, and a diode 112D is configured by a PN junction between the semiconductor substrate 110 and the N ⁺ region 112. The pad 122 is directly connected to the N + region 112 through a contact hole.

The pad 132 formed near the inner peripheral end of the other spiral electrode 130 is used as the ground terminal 132A. Immediately below the pad 132, an end of the spiral electrode 130 connected through the contact hole is arranged, and further below it is a space between the semiconductor substrate 110 and the N ⁺ region 116 formed in a part thereof. A diode 116D formed by a PN junction is disposed.

FIG. 4 is a cross-sectional view of the pad 132. An N ⁺ region 116 is formed in the vicinity of the surface of the P-type semiconductor substrate 110, and a diode 116D is constituted by these PN junctions. An end portion of the spiral electrode 130 is directly formed on the surface of the N + region 116, and the node 132 is connected to the end portion of the spiral electrode 130 through a contact hole.

FIG. 5 is an equivalent circuit diagram of the LC noise filter 100. Since the upper spiral electrode 120 and the lower spiral electrode 130 are arranged so as to overlap each other, a capacitor 140 is formed between them. Accordingly, the spiral electrodes 120 and 130 and the Canon 140 constitute a distributed constant type LC noise filter 100. Also, diodes 112D, 114D, and 116D are connected to the input terminal 122A, the output terminal 124A, and the ground terminal 132A, respectively. These diodes 112D, 114D, and 116D are for input protection, and prevent the insulating layer 202 between the spiral electrodes 120 and 130 from being destroyed when an excessive voltage due to static electricity or the like is applied to the corresponding terminals. . Although the diode 116D is connected only to the vicinity of the inner peripheral end on the spiral electrode 130 side, the withstand voltage can be increased by connecting the diode also to the vicinity of the outer peripheral end. In this case, an N ⁺ region may be formed near the surface of the semiconductor substrate 110 corresponding to the outer peripheral edge of the spiral electrode 130.

FIG. 6 and FIG. 7 are explanatory views of the outline of the manufacturing method of the LC noise filter 100. Although one LC noise filter 100 is shown in FIG. 6 and the like, in practice, a large number of LC noise filters 100 are formed simultaneously using one silicon wafer, and one or more LC noise filters 100 are formed. Predetermined packaging is performed in units of pieces.

First, an insulating layer 200 is formed on the surface of a semiconductor substrate (silicon wafer) 110, and regions corresponding to the N ⁺ regions 112, 114, and 116 are removed using a photolithography method. Next, N ⁺ regions 112, 114, and 116 are formed by thermally diffusing arsenic or the like on the semiconductor substrate 100 through these regions (FIG. 6).

[0028] Next, after depositing a metal material such as aluminum or gold on the surface, a predetermined pattern as a lower spiral electrode 130 is formed by photolithography using a photoresist (FIG. 7). Further, after removing the photoresist, an insulating layer 202 is formed on the surface, and a region corresponding to the N ⁺ regions 112 and 114 and a region corresponding to the inner peripheral edge of the spiral electrode 130 are removed by photolithography. Next, the upper layer spiral electrode 120 and the pad 132 having the pads 122 and 124 at both ends are formed. In this way, the LC noise filter 100 shown in FIG. 1 is completed.

The above-described LC noise filter 100 of the present embodiment can be manufactured as a chip component by performing a predetermined packaging that can be formed as one component included in an LSI. Next, a specific example will be described assuming that a wafer level CSP (Chip Scale Package) is performed on the LC noise filter 100 described above.

FIG. 8 is a cross-sectional view of the LC noise filter 100 shown in FIG. 1, and shows a state before performing wafer level CSP. FIG. 9 is a cross-sectional view of a wafer level CSP corresponding to the LC noise filter 100. 8 and 9 show structures that focus on the parts related to the solder balls that serve as the external connection terminals of the wafer level CSP, and other structures and positional relationships are simplified or It is omitted.

As shown in FIG. 9, in wafer level CSP, pads 132 are connected to solder balls 340 via UBM (underbump metal) 310, Cu rewiring 320, and Cu post 330. The same applies to the other pads.

FIGS. 10 to 13 are diagrams showing a wafer level CSP process. First, a polyimide pattern 302 is formed on the surface of the passivation 300 (FIG. 10A) on the surface of the LC noise finer (FIG. 10B). The passivation 300 is formed on the surface when the LC noise filter 100 is formed. Next, a UBM 310 is formed on the surface of the polyimide pattern 302 so as to be connected to the pad 132 or the like (FIG. 10C). UBM310 consists of Ti layer and Cu layer, for example. Next, a resist pattern 312 is formed on the surface, and a Cu rewiring 320 is formed (FIG. 11A).

[0034] Next, after removing the resist (FIG. 11 (B)), after forming the dry film laminator 322 and removing the scum (FIG. 11 ()), the 01 post 330 is formed (FIG. 12 (8)). Then, after resist stripping and ashing (FIG. 12B), a sealing resin 332 is formed and its surface is polished (FIG. 13A).

Next, after mounting the solder balls 340 on the surface of the Cu post 330 (FIG. 13B), reflow is performed (FIG. 13C). Each of the above steps is performed in the state of a wafer, and then dicing is performed for separating into LC noise filters 100 as chip parts.

FIG. 14 is a diagram showing a specific example of dicing, and shows a case where a chip part including two LC noise filters 100 is manufactured. The chip component shown in FIG. 14 has a size of lmm × 1.4 mm, and includes two LC noise filters 100 therein. Each of the two LC noise filters 100 has an input terminal 122A force corresponding to solder balls 340 provided in the vicinity of different corners. Similarly, each of the two LC noise filters 100 corresponds to a solder ball 340 provided in the vicinity of different corners of the input terminal 124A force provided on each of the two LC noise filters 100. Also, it corresponds to one solder ball 340 provided near the center of the ground terminal 132A force provided in each of the two LC noise filters. In this way, four solder balls 340 corresponding to the input terminal 122A and the output terminal 124A are arranged at the four corners of the chip component having a rectangular shape, and one solder ball 340 corresponding to the ground terminal 132A is arranged at the center. As a result, the grounded central solder ball 340 and the other four solder balls 340 can be largely separated from each other, and the chip component can be miniaturized while ensuring a distance therebetween. In the example shown in FIG. 14, the horizontally long rectangular shape is divided into two in the horizontal direction, and the LC noise filter 100 is associated with each divided region. However, the horizontally long rectangular shape is divided into two in the vertical direction, and The LC noise filter 100 may be associated with the divided areas.

As described above, the LC noise filter 100 according to the present embodiment is provided with the diodes 112D, 114D, and 116D as input protection circuits at the ends of the spiral electrodes 120 and 130, thereby providing an anti-resistance. By increasing the pressure, breakdown due to static electricity or the like (insulation breakdown of the insulating layer 202 disposed between the spiral electrodes 120 and 130) can be prevented. In addition, when the double spiral electrodes 120 and 130 are formed using a two-layer metal structure, the upper spiral electrode 120 is generally thicker depending on the manufacturing process. Therefore, the resistance of the signal line can be lowered by using the spiral electrode 120 as the signal line.

[0038] The upper spiral electrode 120 is provided with diodes 112D and 114D as input protection circuits at both ends, and the lower spiral electrode 130 is a diode 116D as an input protection circuit at the grounded end. Is provided. As a result, a distributed constant type LC noise filter 100 can be realized, and a noise component included in a signal input to the upper spiral electrode 120 can be removed.

[0039] In addition, the lower spiral electrode 130 may be provided with a diode as an input protection circuit at the other end as well as at the end to be grounded. As a result, the breakdown voltage of the LC noise filter 100 can be further increased.

[0040] Further, as the input protection circuit, diodes 112D, 114D, and 116D formed by PN junctions formed on the semiconductor substrate 110 are used. As a result, when an excessive voltage is applied to at least one of the spiral electrodes 120 and 130, a current can flow to the semiconductor substrate 110 side, and insulation breakdown between the spiral electrodes 120 and 130 due to the excessive voltage can be prevented. I can do it.

In addition, the grounded end of the lower layer spiral electrode 130 is disposed on the inner peripheral side end. This eliminates the need to form a connection pad on the outer peripheral side of the spiral electrode 130, so that when the size of the semiconductor substrate 110 is constant, the spiral electrode 130 and the spiral formed on the spiral electrode 130 are overlapped. The diameter of the outermost periphery of the electrode 120 can be increased, and a large inductance can be secured.

[0042] Further, the overlapping area of the spiral electrodes 120 and 130 may be varied according to the frequency characteristics. As a result, only the characteristics can be changed without changing the area or terminal arrangement of the LC noise filter 100.

[0043] Pads are connected to both ends of the upper spiral electrode 120 and one end of the lower spiral electrode 130, respectively, and are connected by a wafer level CSP (Chip Scale Package). Packaging. As a result, when the LC noise filter 100 is formed as a chip component, the chip component can be reduced in size.

In addition, a plurality of sets of spiral electrodes 120 and 130 and diodes 112D, 114D, and 116D as input protection circuits (two sets in the example shown in FIG. 14) are formed on a common semiconductor substrate 110. As a result, a small chip component with a large number of built-in LC noise filters 100 can be realized. In particular, one end of the lower layer spiral electrode 130 included in the plurality of sets is connected to each other, thereby reducing the number of terminals for external connection in a chip component incorporating a plurality of LC noise filters 100. Therefore, the maximum distance between these terminals can be secured. In other words, it is possible to reduce the size of the chip component when it is necessary to ensure a certain distance between the terminals for external connection.

Note that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, in the above-described embodiment, the spiral electrode 130 may be connected to an external terminal in which the pad 132 is connected to the inner terminal. Alternatively, solder paste may be printed instead of the force used to use the solder balls 340 in the wafer level CSP. Further, in the example shown in FIG. 14, the LC noise filter 100 having three or more forces in which two LC noise filters 100 are included in one chip component may be included.

Industrial applicability

[0046] According to the present invention, by providing the input protection circuit at the end of the inductor conductor, the breakdown voltage can be increased and the breakdown due to static electricity or the like can be prevented.

Claims

The scope of the claims

[1] a first inductor conductor formed on a semiconductor substrate;

The semiconductor substrate is formed on the semiconductor substrate, and at least a part of the first inductor conductor overlaps with a predetermined distance maintained, and the overlapped part is located farther from the semiconductor substrate than the first inductor conductor. A second inductor conductor disposed in the

An input protection circuit comprising a semiconductor element connected to ends of the first and second inductor conductors and formed on the semiconductor substrate;

LC noise filter with

[2] In claim 1,

The second inductor conductor is an LC noise filter used for a signal line through which signals are input and output, and the first inductor conductor is grounded at one end.

[3] In claim 2,

The LC noise filter, wherein the second inductor conductor is provided with the input protection circuit at both ends, and the first inductor conductor is provided with the input protection circuit at a grounded end.

[4] In claim 3,

The LC noise filter, wherein the first inductor conductor is provided with the input protection circuit at the other end as well as the end that is grounded.

[5] In claim 1,

The LC noise filter, wherein the input protection circuit is a diode formed by a PN junction formed on the semiconductor substrate.

[6] In claim 2,

The end of the first inductor conductor that is grounded is an inner peripheral end. LC noise filter

[7] In claim 1,

LC noise filter whose frequency characteristics are adjusted by changing the overlapping area of the first and second inductor conductors.

[8] In claim 1, An LC noise filter in which pads are connected to both ends of the second inductor conductor and one end of the first inductor conductor, and packaging is performed by wafer level CSP (Chip Scale Package).

[9] In claim 8,

An LC noise filter, wherein the first and second inductor conductors and the input protection circuit are formed on the semiconductor substrate common to a plurality of sets.

[10] In claim 9,

The second inductor conductor is used for a signal line through which signals are input and output, and the first inductor conductor is grounded at one end,

An LC noise filter in which one ends of a plurality of first inductor conductors corresponding to the plurality of sets are connected to each other.