JP2006066507A - Printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board for high speed transmission and miniaturized equipment by preventing malfunction due to signal multiple reflections or breakage of a transmission/reception device. <P>SOLUTION: A high speed transmission path is provided across a plurality of inner layers, and the high speed transmission path is provided with a resistor having a width similar to the wiring width of the high speed transmission path. A plurality of high speed transmission paths are provided across a plurality of inner layers, and a resistor is connected in the middle of the plurality of high speed transmission paths through hole. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printed wiring board with a built-in resistor, and more particularly to a printed wiring board for preventing malfunction due to signal multiple reflection and breakage of a transmission / reception device, realizing high-speed transmission and miniaturization of equipment.

  The following Patent Documents 1 to 3 and the like are known as conventional examples related to such a printed wiring board. That is, Patent Document 1 relates to a high-frequency printed wiring board and a method for manufacturing the same, and a technique that can reduce reflection and loss of signals transmitted between a plurality of printed wiring boards without using a coaxial cable or a high-frequency connector. Is disclosed.

  Patent Document 2 relates to an auxiliary package for wiring and a printed wiring board structure provided with the package, and is a technique capable of high-speed signal transmission and impedance matching with internal circuit wiring and high-density wiring. Disclosure. Further, Patent Document 3 relates to a printed wiring board and a manufacturing method thereof, and realizes a single low dielectric constant resin thick film laminated structure without reinforcing material without causing a decrease in mechanical strength. The technology is disclosed.

  However, even in these techniques, when mounting a resistor for damping or terminating treatment on a transmission line, surface mounting or solder contact is required as before, and there is a problem that malfunction due to multiple signal reflection and damage to a transmission / reception device are likely to occur.

  FIG. 6 is an explanatory plan view of an essential part of a conventional general printed wiring board. In this figure, 100 is a signal transmission unit, and 200 is a signal reception unit. The microstrip lines 301 to 303 are connected to the microstrip lines 301 'to 303' via chip resistors 401 to 403, respectively.

  In the conventional example having such a configuration, chip resistors 401 to 403 are inserted and connected to a transmission line composed of microstrip lines 301 to 303 and microstrip lines 301 'to 303' for the purpose of damping processing. For this reason, discontinuous parts are generated as transmission lines in land portions formed so as to thicken the lines and solder joints where the chip parts are brazed, and random signals are reflected and attenuated. It was a problem in transmission.

  In addition, it is known that a resistor for performing a termination process is connected to a product that realizes a transmission line such as a microstrip line on a printed wiring board. This is performed in order to prevent harmful signal reflection by matching the input / output impedance of the device connected to the input / output end of the line in order to prevent malfunction of the equipment.

  Further, a resistor for the purpose of damping processing is inserted and connected in the middle of the transmission line in order to prevent multiple reflection of reflected signal waves. These resistors are pre-formed lands for connecting parts at the end of the transmission line or in the middle, and are used by being mounted via the land parts, or soldered connection parts where the chip parts are brazed It is used by mounting via

  In general, electronic components such as resistors can be arranged only on the surface layer of a printed wiring board. However, in the case of a multilayer printed wiring board, the transmission line is often formed in a plurality of inner layers, and in order to connect these resistors, the wiring is drawn out to the surface layer through a through hole, and a land is provided at the end. It is necessary to install.

  In high-speed transmission lines such as those described above, it is common to handle multiple synchronized signals as bus lines, but resistors for termination and damping purposes are wired through through-holes and solder is used on the lands. From the viewpoint of signal integrity, signal timing mismatch due to wasted wiring, or reflection and attenuation of signals at the land where through-holes and components are mounted, occur. It was a problem.

  In addition, the amount of transmitted signals is increasing in printed wiring boards used in recent high-density electronic equipment, which increases the influence of electrical characteristics due to over-concentration of transmission lines due to increased bus width and higher frequencies. It was. For this reason, there existed a problem that the above-mentioned resistor could not be arranged even if the whole device could not be reduced in size due to a malfunction of the device or an increase in physical dimensions, even if it could be downsized.

Furthermore, in products that have realized high-speed transmission lines with printed wiring boards, insertion of termination resistors for terminating transmission signals and insertion of resistors in the middle of wiring for the purpose of damping treatment to prevent multiple reflections There was a need to do. For this reason, in a high-speed transmission line such as a giga band, the land for mounting the resistor and the shape of the conductive material solder used for bonding become discontinuous with the wiring. There is also a problem that transmission signals are reflected or attenuated due to mismatching of the signals.
JP 2001-135899 A JP 2003-309121 A JP 2001-119111 A

  The present invention has been made in view of the above-mentioned problems, and the problem is that a transmission line such as a microstrip line that transmits a high-speed signal formed on a printed wiring board has malfunctioned due to signal multiple reflection. It is an object of the present invention to provide a printed wiring board that incorporates a termination resistor and a damping resistor for preventing breakage of a transmission / reception device in the wiring board, thereby realizing high-speed transmission and downsizing of the device.

  In order to solve the above-mentioned problem, the present invention according to claim 1 provides a high-speed transmission path over a plurality of inner layers in a printed wiring board, and the high-speed transmission path has substantially the same width as the wiring width of the transmission path. A resistor is provided. As a result, a printed circuit board that incorporates termination resistors and damping resistors to prevent malfunctions due to multiple signal reflections and damage to transmission / reception devices is realized in the circuit board, enabling high-speed transmission and miniaturization of equipment. Realize.

According to a second aspect of the present invention, the transmission line is a microstrip line.
According to a third aspect of the present invention, the resistor is formed integrally with a transmission line.

  According to a fourth aspect of the present invention, the resistor is a metal thin film resistor.

In the present invention according to claim 5, the resistor is an organic resin thick film resistor.
According to a sixth aspect of the present invention, the organic resin thick film resistor is a polymer paste printing resistor.

In the present invention according to claim 7, the resistor is a thick film resistor made of an inorganic material.
In the present invention according to claim 8, the thick film resistor made of an inorganic material is a ceramic thick film resistor.

According to a ninth aspect of the present invention, in order to solve the above problem, in the printed wiring board, a plurality of high-speed transmission paths are provided across a plurality of inner layers, and through holes are formed in a part of the plurality of high-speed transmission paths. This is characterized in that a resistor is connected halfway through.
In the present invention according to claim 10, the resistor is a chip resistor.

  According to the present invention, since the resistor is formed with the same width as that of the high-speed transmission line, it is not affected by signal reflection or attenuation due to partial characteristic impedance mismatch on the transmission line. Ideal signal processing becomes possible.

  In addition, since it is possible to place resistors on multiple inner layers of a multilayer printed wiring board, unnecessary wiring routing is not necessary, wiring discontinuity does not occur in the through-hole, and isometric wiring rules are It will not collapse. Therefore, no reflection or attenuation of the signal occurs, and the principle of equal-length wiring is maintained, and the reliability of the signal does not deteriorate due to timing mismatch of signals.

  Furthermore, when a plurality of high-speed transmission lines are provided across a plurality of inner layers and a resistor is connected to a part of the transmission line through a through hole, the degree of freedom in arranging the resistors increases. There is an advantage.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not restrict | limited at all by embodiment described in detail below, A various change is possible within the scope of the present invention.

FIG. 1 is an explanatory plan view of a main part showing a first embodiment of the present invention. In FIG. 1, 100 is a signal transmitting unit, 200 is a signal receiving unit, 311 to 313, 311 ′ to 313 ′ are high-speed transmissions. Microstrip lines 501 to 503 are resistors.
Examples of the resistors 501 to 503 include metal thin film resistors, organic resin thick film resistors such as polymer paste printing resistors, and inorganic material thick film resistors such as ceramic. The resistors 501 to 503 are preferably formed integrally with the microstrip lines 311 to 313 and 311 ′ to 313 ′, and constitute a forming resistor, for example.

  2 is a cross-sectional explanatory view taken along the line A-A 'of FIG. 1. In FIG. 2, the same symbols as those in FIG.

  In FIG. 2, 500 and 510 are solder resists, 600 and 610 are first insulating layers made of, for example, glass epoxy resin laminated to a thickness of 60 μm, 701 to 703 and 711 to 713 are wiring lines, and 800 and 810 are For example, a second insulating layer made of glass epoxy resin or the like laminated to a thickness of 60 μm, 900 and 910 are ground layers, and 1000 is a core substrate made of glass epoxy resin or the like laminated to a thickness of 400 μm, for example. In addition, L1-L6 has shown each layer of the multilayer printed wiring board.

  In the first embodiment of the present invention configured as described above, the widths of the resistors 501 to 503 in FIG. 1 are substantially the same as the wiring widths of the microstrip lines 311 to 313 and 311 ′ to 313 ′, respectively. Are equal.

  In the present invention, the resistors 501 to 503 are metal thin film resistors, organic resin thick film resistors, or the like as described above, but are 100Ω or less for the purpose of transmission line damping processing and signal termination processing. The low resistance is preferable. Moreover, when it is requested | required that a temperature characteristic is favorable, a metal thin film resistor is preferable.

  In the present invention, the wiring width of the transmission line is usually preferably about 0.07 mm to 0.20 mm. In order to prevent signal crosstalk, the wiring space is preferably set to 2-3 times the wiring width of the transmission line, particularly about 0.20 to 0.30 mm.

  Maintaining this design rule, a resistor using, for example, a metal thin film can be formed and arranged on a part of the transmission line. As a result, an ideal signal transmission form can be obtained without performing any unnecessary wiring routing required for placement of through-holes and via lands and components that impede transmission characteristics.

  On the other hand, FIG. 3 is an explanatory plan view showing the main part of the second embodiment of the present invention. In FIG. 3, the same symbols as those in FIG. . In FIG. 3, 331 to 333, 331 'to 333' are microstrip lines, and 411 is a resistor composed of a chip resistor.

  4 is a cross-sectional view taken along the line B-B 'of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line C-C' of FIG. In these figures, the same symbols as those in FIGS. 1 to 3 are used with the same meanings, and redundant explanations are omitted here. In FIG. 5, 412 is a resistor composed of a chip resistor, and 1100 and 1110 are conductive through holes.

  In the second embodiment of the present invention configured as described above, the microstrip lines 331 and 331 'are electrically connected to the resistor 412 through the through holes 1100 and 1110 in FIG.

  That is, the second embodiment of the present invention configured as shown in FIGS. 3 to 5 differs from the first embodiment shown in FIGS. 1 and 2 in that a plurality of inner layers are divided into a plurality of layers. High-speed transmission lines (for example, microstrip lines 331 to 333, 331 ′ to 333 ′) are provided, and through holes (for example, through holes 1100 and 1110) are provided in some of the transmission lines (for example, microstrip lines 332 and 332 ′). A resistor (for example, a resistor 411) is connected in the middle.

Therefore, compared with the case of the first embodiment shown in FIG. 1 and FIG. 2, the effect of reducing signal reflection and loss is small, but compared with the case of the conventional example shown in FIG. The signal flowing through the signal line on the board has a small change in characteristic impedance, and can reduce signal reflection and loss.
In addition, there is an advantage that the degree of freedom in arranging the resistors is increased as compared with the conventional example shown in FIG.

  The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in a multilayer printed wiring board provided with a high-speed transmission path, a high-speed transmission path is provided across a plurality of inner layers. A resistor having a size substantially the same as the width of the wiring may be formed in a part of the wiring and at an electrically convenient position.

The principal part plane explanatory view which shows 1st Embodiment of this invention printed wiring board. FIG. 2 is a cross-sectional explanatory diagram of A-A ′ in FIG. 1. The principal part plane explanatory drawing which shows 2nd Embodiment of this invention printed wiring board. B-B 'cross-sectional explanatory drawing of FIG. C-C 'cross-sectional explanatory drawing of FIG. The principal part plane explanatory drawing of the conventional printed wiring board.

Explanation of symbols

100: signal transmission unit 200: signal reception units 301 to 303, 301 ′ to 303 ′: microstrip line (high-speed transmission path)
401-403, 501-503: Resistor 411, 412: Resistor (chip resistor)
500, 510: Solder resist 600, 610: First insulating layers 701 to 703, 711 to 713: Wiring pattern 800, 810: Second insulating layer 900, 910: Ground layer 1000: Core base material 1100, 1110: Through hole

Claims (10)

  A printed wiring board, wherein a high-speed transmission path is provided across a plurality of inner layers, and a resistor having a width substantially the same as the wiring width of the high-speed transmission path is provided in the high-speed transmission path.   The printed wiring board according to claim 1, wherein the high-speed transmission path is a microstrip line.   The printed wiring board according to claim 1 or 2, wherein the resistor is formed integrally with the high-speed transmission path.   The printed wiring board according to claim 1, wherein the resistor is a metal thin film resistor.   The printed wiring board according to claim 1, wherein the resistor is an organic resin thick film resistor.   6. The printed wiring board according to claim 5, wherein the organic resin thick film resistor is a polymer paste printing resistor.   The printed wiring board according to any one of claims 1 to 3, wherein the resistor is a thick film resistor made of an inorganic material.   8. The printed wiring board according to claim 7, wherein the inorganic material thick film resistor is a ceramic thick film resistor.   A printed wiring board, wherein a plurality of high-speed transmission paths are provided over a plurality of inner layers, and a resistor is connected to a part of the plurality of high-speed transmission paths through a through hole.   The printed wiring board according to claim 9, wherein the resistor is a chip resistor.

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