JP4535894B2 - Wiring board - Google Patents

Description

  The present invention relates to a wiring board in which a signal line is disposed inside an insulating substrate and a ground conductor layer is disposed on both upper and lower sides of the signal line.

  A wiring board having a signal line for transmitting electrical signals transmitted to and received from electronic components such as semiconductor elements and transmitting elements, particularly high-frequency signals such as 1 GHz band, is generally an aluminum oxide sintered body or a glass ceramic sintered body. A plurality of insulating layers made of an electrically insulating material such as a ceramic sintered body, an organic resin such as an epoxy resin or a polyimide resin, or a composite material formed by bonding an inorganic powder such as aluminum oxide with an organic resin such as an epoxy resin. It has a laminated insulating substrate, a signal line formed inside the insulating substrate, and a pair of ground conductor layers formed on both upper and lower sides of the signal line (inside and exposed surface of the insulating substrate).

  An electrostatic capacitance (capacitance) is generated according to the thickness of the insulating layer and the number of layers (that is, the thickness of the intervening dielectric) interposed between the ground conductor layer and the signal line, and the impedance of the signal line is determined by this capacitance. Adjusted to the value of.

  For example, a part of the signal line is led out to the surface of the insulating substrate via a through conductor formed on the insulating substrate, and an electronic component is mounted on the insulating substrate, and the electrode of the electronic component is connected to the signal line. Electrically connected to the lead-out part via a bonding wire, solder, etc., and if necessary, the electronic component is sealed with a lid, sealing resin, etc. For example, the electronic device can be completed with an electric signal such as a high-frequency signal of 1 GHz or more with a circuit.

The electronic components are specifically semiconductor integrated circuit devices such as IC and LSI, LD (semiconductor laser), LED (light emitting diode), PD (photodiode), CCD (charge coupled device), line sensor, image sensor. Optical semiconductor elements such as MEMS, micro electro mechanical system (MEMS) semiconductor elements, vibrators such as piezoelectric vibrators and crystal vibrators, capacitive elements, and various other electronic components. , Used as a part of electronic devices such as mobile phones, computers, routers.
JP 2004-252311 A JP 2002-184245 A

  However, in such a wiring board, in recent years, there has been an increasing demand for forming a plurality of signal lines having different impedances on an insulating substrate in order to provide a single circuit with high functionality. In this case, the wiring board is formed by laminating a plurality of signal lines with different thicknesses of the insulating substrate interposed between the upper and lower ground conductor layers according to a predetermined impedance required for each signal line. There was a problem that it was necessary to have a structure and it was difficult to reduce the thickness.

  The present invention has been devised in view of the above-mentioned problems, and its purpose is to adjust the impedance of a signal line to a predetermined value in a wiring board in which signal lines having different impedances are arranged inside. An object of the present invention is to provide a wiring board that can be easily reduced in thickness.

Wiring board of the present invention, as well to arrange the signal line in the insulating substrate, a wiring substrate formed by placing a pair of ground conductor layers on both upper and lower sides of the signal line, the signal line and each of said grounding conductor A pair of auxiliary ground conductor layers are disposed opposite each other so that at least a part of the signal line is sandwiched between the layers, and both ends of the pair of auxiliary ground conductor layers are arranged in the width direction of the signal line. It is characterized by extending outward from both ends and having the same width .

Further, the wiring board of the present invention, the signal line is provided more inside the insulating substrate, it is characterized in that the plurality of the signal lines are arranged parallel to each other.

According to the wiring board of the present invention, together with to arrange the signal line in the insulating substrate, the wiring substrate made by placing a pair of ground conductor layers on both upper and lower sides of the signal line, the signal line and the respective ground conductor layers Since the pair of auxiliary grounding conductor layers are arranged opposite each other so that at least a part of the signal line is sandwiched between them, the impedance of the signal line is adjusted according to the distance between the auxiliary grounding conductor layer and the signal line can be, even when the placing different signal line impedance, it is not necessary to the thickness of the insulating substrate interposed between the upper and lower sides of the ground conductor layer is laminated different signal lines, the thin It can be easily handled.

Further, according to the wiring board of the present invention, a pair of auxiliary ground conductor layer, by being the same width is extended outward from the width direction of both ends in the width direction of the both ends the signal line, and causing capacitance enabled between the auxiliary ground conductor layer and the signal line, reduce the impedance of the signal line is, play a significant width, and easily becomes able ones, correspond to the wide range of impedance values and that can be thin type of is and the wiring board as possible.

  Furthermore, according to the wiring board of the present invention, by providing a plurality of the signal lines inside the insulating substrate and arranging the plurality of signal lines in parallel with each other, the distance between the signal lines becomes constant, Therefore, it is possible to obtain a wiring board capable of obtaining a more stable impedance without impedance change.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment of a wiring board according to the present invention. FIG. 1A is a cross-sectional view showing an example of an embodiment of a wiring board according to the present invention. FIG. 2 is a partial plan perspective view of FIG.

  In FIG. 1, 1 is an insulating substrate, 2 is a signal line, 3 is a ground conductor layer, and 4 is an auxiliary ground conductor layer. A wiring substrate 9 is basically constituted by the insulating substrate 1, the signal line 2, the ground conductor layer 3, the auxiliary ground conductor layer 4, and the like.

  The insulating substrate 1 is an aluminum oxide sintered body, a glass ceramic sintered body, an aluminum nitride sintered body, a ceramic sintered body such as a mullite sintered body, an organic resin such as an epoxy resin or a polyimide resin, or an aluminum oxide. Etc. are formed of an electrically insulating material such as a composite material formed by bonding an inorganic powder such as an epoxy resin with an organic resin.

The insulating substrate 1 is produced as follows when a plurality of insulating layers made of, for example, an aluminum oxide sintered body are laminated. First, an appropriate organic binder and solvent are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, calcium oxide, and magnesium oxide to produce a slurry-like ceramic slurry. A ceramic green sheet (ceramic green sheet) is obtained by forming a sheet by employing the sheet forming technique. Thereafter, ceramic green sheets are laminated in the predetermined order in the vertical direction to form a green ceramic molded body. The green ceramic body is fired in a reducing atmosphere at a high temperature of about 1600 ° C., whereby the insulating substrate 1 is manufactured.

  A signal line 2 is disposed inside the insulating substrate 1.

  The signal line 2 has a function of transmitting an electric signal transmitted / received to / from an electronic component such as a semiconductor element or an oscillation element. For example, when an electronic component (not shown) is mounted on the wiring board 9, the signal transmitted through the signal line 2 is transmitted between the electronic component and a circuit on an external electric circuit board on which the wiring board is mounted. A high-frequency signal such as a 1 GHz band is transmitted.

  Specific examples of electronic components include semiconductor integrated circuit elements such as IC and LSI, LD (semiconductor laser), LED (light emitting diode), PD (photodiode), CCD (charge coupled device), line sensor, An optical semiconductor element such as an image sensor, a semiconductor element for MEMS (Micro Electro Mechanical System), a vibrator such as a piezoelectric vibrator and a crystal vibrator, a capacitive element, and other various electronic components are used.

  A pair of ground conductor layers 3 are arranged on both upper and lower sides of the signal line 2 (for example, both main surface sides of the insulating substrate 1).

  The ground conductor layer 3 has a function of adjusting the impedance of the signal line 2 to a predetermined value by generating a certain capacitance between the ground conductor layer 3 and the signal line 2. In other words, depending on the thickness of the insulating substrate 1 interposed between the ground conductor layer 3 and the signal line 2 (thickness or number of layers of the insulating layer 1a), there is an electrostatic charge between the ground conductor layer 3 and the signal line 2. A capacitance is generated, and the impedance of the signal line 2 is lowered according to the capacitance. Therefore, the impedance of the signal line 2 can be adjusted to a predetermined value by adjusting the distance between the ground conductor layer 3 and the signal line 2.

  The signal line 2 and the ground conductor layer 3 are formed of a metal material such as tungsten, molybdenum, manganese, copper, silver, palladium, gold, or platinum. If the signal line 2 and the ground conductor layer 3 are made of tungsten, for example, an appropriate inorganic filler powder, an organic solvent, a binder, etc. are added to the tungsten powder to produce a metal paste, and the metal paste is used as an insulating substrate. It is formed by printing a predetermined signal line 2 or ground conductor layer 3 pattern on the ceramic green sheet 1.

  Further, the metal material may be formed in a predetermined pattern in the form of a plating layer, a vapor deposition layer, a metal foil, or the like instead of the form of the metallized layer.

  A pair of auxiliary grounding conductor layers 4 are disposed between the signal line 2 and each grounding conductor layer 3 so as to face at least a part of the signal line 2.

  By arranging the auxiliary ground conductor layer 4 in this way, the impedance of the signal line 2 can be adjusted according to the distance between the auxiliary ground conductor layer 4 and the signal line 2. Even in the case of different impedances, it is not necessary to stack the signal lines 2 having different thicknesses of the insulating substrate 1 interposed between the ground conductor layers 3 on both the upper and lower sides. Will be able to.

  The auxiliary ground conductor layer 4 can be formed using the same metal material as that of the ground conductor layer 3 by the same means (such as application of a metal paste that becomes a metallized layer).

  In addition, the auxiliary grounding conductor layer 4 needs to be disposed oppositely so as to sandwich at least a part of the signal line 2 in order to adjust the impedance of the signal line 2 to a predetermined value. Further, depending on the impedance value to be adjusted or the like, not limited to a part, the entire region may be disposed so as to face each other.

  Furthermore, the distance between the signal line 2 and each of the pair of auxiliary ground conductor layers 4 is the same distance.

  The closer the distance between the auxiliary grounding conductor layer 4 and the signal line 2 is, the larger the capacitance generated between them becomes, so that the impedance of the signal line 2 can be lowered. In order to reduce the distance between the auxiliary ground conductor layer 4 and the signal line 2, for example, the thickness of the insulating layer interposed between the signal line 2 and the auxiliary ground conductor layer 4 can be reduced, or the number of layers can be reduced. Or less.

  Furthermore, there is no particular limitation on the shape of the signal line 2 as long as it is shaped and dimensioned so that a pair of the signal lines 2 are opposed to each other so as to sandwich at least a part thereof. Since the signal line 2 has a line shape (extremely long and narrow rectangular shape), the rectangular shape is optimal for the above purpose. However, depending on the shape of the other signal lines 2 and the insulating substrate 1, etc. A notch part, a bulging part, etc. may be provided, and elliptical shape etc. may be sufficient.

The pair of auxiliary ground conductor layer 4, because it is the same width is extended outward from both ends of both ends in the width direction of the signal line 2 in the width direction, the auxiliary ground conductor layer 4 and the signal and causing capacitance enabled between the lines 2, reducing the impedance of the signal line 2 is, play a significant width, and easily becomes able ones, and correspond to a wide range of impedance values, it can be thin type of is and the wiring substrate 9 as possible.

Thus, a pair of auxiliary ground conductor layer 4, that is the same width is extended outward from both ends at both ends in the width direction of the width direction of the signal line 2.

In this way, the insulating substrate 1, if formed by laminating a plurality of insulating layers, a pair of auxiliary ground conductor layer 4 is, outward from the ends of both ends in the width direction of the signal line 2 in the width direction Since the extension is made to have the same width , the signal line 2 and the auxiliary ground conductor can be used even when the signal line 2 and the auxiliary ground conductor layer 4 are misaligned between the insulating layers. it is possible to effectively prevent that the opposing area between the layer 4 varies, it can be an excellent wiring board reliability.

  Further, when a plurality of signal lines 2 are provided inside the insulating substrate 1 and the plurality of signal lines 2 are arranged in parallel to each other, the distance between the signal lines 2 becomes constant and the impedance partially changes. Thus, the wiring board can obtain a more stable impedance without being performed.

  Therefore, it is preferable that a plurality of signal lines 2 are provided inside the insulating substrate 1, and the plurality of signal lines 2 are arranged in parallel to each other.

  Further, the lead-out portion when a part of the signal line 2 is led to the surface of the insulating substrate 1 and the surface exposed to the outside of the ground conductor layer 3 and the auxiliary ground conductor layer 4 are mainly nickel, gold, copper, or these. It is preferable to coat with a plating layer such as an alloy as a component. In this case, the oxidative corrosion of the exposed surface can be effectively prevented, and a more reliable wiring board can be obtained. Further, it is possible to improve characteristics such as solder wettability and bonding wire bonding property when an electronic component is connected to the lead-out portion of the signal line 2.

Wiring board 9 of this embodiment as described above, a portion of the signal line 2, the leading out to the surface of the insulating substrate 1 via a through conductor or the like formed on an insulating substrate 1 (not shown), an insulating substrate 1 An electronic component is mounted on the main surface, and an electrode (not shown) of the electronic component is electrically connected to a lead-out portion of the signal line 2 via a conductive connecting material (not shown) such as a bonding wire or solder. If necessary, the electronic parts can be sealed with a lid, sealing resin, etc., so that electrical signals (high frequency) can be exchanged between the electronic parts and an external electric circuit via the signal line 2. Electronic device.

  For example, if the electronic component is mounted on the main surface (upper surface or the like) of the insulating substrate 1 and the electronic component is hermetically sealed using a lid, the electronic component of the insulating substrate 1 is mounted. A lid (not shown) is prepared so as to cover the area that is covered, the lid is attached to the main surface of the insulating substrate 1, and an electronic component is formed inside the container formed by the insulating substrate 1 and the lid. Is sealed to form an electronic device. The lid is formed of a metal material such as an iron-nickel-cobalt alloy, a ceramic material such as an aluminum oxide sintered body, a resin, glass, or the like. Further, the lid is attached to the insulating substrate 1 by means such as joining or welding via a joining material such as a brazing material, resin or glass. The formed electronic device is used as a part of electronic devices such as various sensor devices, mobile phones, computers, and routers.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the scope of the present invention.

(A) is sectional drawing which shows an example of embodiment of the wiring board of this invention, (b) is a partial plane perspective view of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulation board 2 ... Signal line 3 ... Grounding conductor layer 4 ... Auxiliary grounding conductor layer 9 ... Wiring board

Claims (2)

A wiring board in which a signal line is arranged inside an insulating substrate, and a pair of ground conductor layers are arranged on both upper and lower sides of the signal line,
Between the signal line and each of said grounding conductor layer, wherein the pair of auxiliary ground conductor layer so as to sandwich at least a portion of the signal line is arranged to face, the pair of auxiliary ground conductor layer, both ends in the width direction Is extended to the outside from both ends in the width direction of the signal line to have the same width . Wherein the signal line has a plurality provided inside the insulating substrate, the wiring board according to claim 1 Symbol mounting, characterized in that the plurality of the signal lines are arranged parallel to each other.

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