JP2003249759A - Multilayer printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a multilayer printed wiring board in which voltage drop of a power supply circuit or a ground circuit is prevented and generation of simultaneous switching noise is prevented. <P>SOLUTION: The multilayer printed wiring board comprises a core board 5 where through conductors 3 penetrate an insulating basic body 2 and connection lands 4 extended from the through conductors 3 are provided on the surface of the insulating basic body 2, and a multilayer wiring part consisting of a plurality of insulation layers 7 and a plurality of wiring conductor layers 8 laid in layers on the surface of the core board 5 wherein an insulation layer 7a between the connection land 4 and the opposite wiring conductor layer 8 is thicker than other insulation layers 7. Since electromagnetic coupling is reduced between the connection land 4 and the wiring conductor layer 8, mismatch of characteristic impedance is prevented from occurring at the connection land 4 part. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a package for housing a semiconductor element for housing a semiconductor element or an electronic circuit board on which a semiconductor element or an electronic component is mounted. The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board having a wiring structure suitable for housing or mounting a semiconductor element operating at high speed. [0002] Conventionally, microprocessors and ASICs
(Application Specific Integrated Circuit) and other electronic components such as semiconductor elements are mounted on a multilayer wiring board used for an electronic circuit board or the like. In forming a wiring conductor for internal wiring, alumina ceramics or the like is used. The insulating layer made of ceramic and the wiring conductor layer made of a high melting point metal such as tungsten (W) are alternately laminated to form a multilayer wiring board. On the other hand, as the demand for improving the information processing capability has increased, the operating speed of the semiconductor element has been increased, and the signal wiring among the wiring conductors for the internal wiring has characteristic impedance matching and crossover between the signal wirings. There has been a demand for improvement of electrical characteristics such as reduction of talk noise. In order to cope with such a demand, the wiring structure of the signal wiring is a strip line structure, and a wide-area power supply wiring layer or a ground (ground) wiring layer is formed above and below the signal wiring via an insulating layer. Was. However, in such a multilayer wiring board, since the insulating layer is made of alumina ceramic or the like having a relative dielectric constant of about 10, the electromagnetic coupling between the signal wirings is increased, so that the crosstalk noise is increased. As a result, there has been a problem that the operation speed of the semiconductor element cannot be increased. Therefore, instead of using alumina ceramic having a relative dielectric constant of about 10 for the insulating layer, an organic material such as polyimide or epoxy resin is used for a glass epoxy resin base material having a relatively small relative dielectric constant of 3 to 5. A so-called build-up substrate formed by using such a method has come to be used. In such a build-up substrate, a conductor film for internal wiring made of copper (Cu) is formed on an insulating layer by using a thin film forming technique such as a plating method, a vapor deposition method, or a sputtering method, and the photolithography method or the like. By forming a fine pattern wiring conductor layer by etching method, by alternately laminating this insulating layer and wiring conductor layer in multiple layers,
2. Description of the Related Art Fabrication of a multi-layer wiring board having high density, high functionality, and capable of high-speed operation of a semiconductor element has been performed. In addition, as the operation speed of the semiconductor device is increased, the operation speed of the semiconductor device cannot be increased due to the mismatch of the characteristic impedance of the through conductor formed in the multilayer wiring board. Has also occurred. Therefore, in order to cope with such a problem,
A wiring structure as disclosed in JP-A-2000-77808 has been proposed. This is one in which an opening having an area equal to or larger than the cross-sectional area of the through conductor is formed in the wiring conductor layer formed to face the through conductor. According to this method, it is possible to effectively prevent the occurrence of characteristic impedance mismatch in the through conductor portion, and thus it is possible to suppress signal reflection. In addition, the number of signals has been increasing with the increase in the operating speed of semiconductor devices. In response to such a demand, the build-up substrate can form a fine pattern of wiring conductors, and thus has been used as a wiring substrate on which a semiconductor element operating at high speed is mounted. However, in the build-up board, since the size of the connection land extending from the through conductor formed on the core board in the build-up board is large, the build-up board faces the connection land. If an opening having an area equal to or larger than the cross-sectional area of the through conductor is formed in the formed wiring conductor layer, the opening of the wiring conductor layer becomes large, the number of conductors decreases, and the resistance value and inductance value of the wiring conductor layer increase. However, there is a problem that simultaneous switching noise increases. The simultaneous switching noise is a phenomenon in which noise is generated in a power supply or ground circuit at the time of signal switching, and the noise tends to increase as the inductance value of the power supply or ground wiring conductor layer increases. In particular, when a semiconductor element which operates at a high speed with a signal frequency of 1 GHz or more is mounted, the problem of simultaneous switching noise occurs remarkably. Further, when the resistance value of the power supply or ground wiring conductor layer increases, a voltage drop occurs in the power supply or ground circuit, and a desired voltage value cannot be obtained. SUMMARY OF THE INVENTION The present invention has been completed to solve the above problems, and an object of the present invention is to alleviate mismatching of characteristic impedance at a connection portion between a signal wiring conductor and a signal through conductor and to achieve simultaneous switching. An object of the present invention is to provide a multilayer wiring board which can reduce noise and is suitable for an electronic circuit board or the like on which electronic components such as semiconductor elements operating at high speed are mounted. According to the present invention, there is provided a multilayer wiring board comprising: an insulating base; a through conductor penetrating the insulating base; and a connection land extending from the through conductor on a surface of the insulating base. A core substrate, and a multilayer wiring portion including a plurality of insulating layers and a plurality of wiring conductor layers laminated on the surface of the core substrate, between the connection land and the wiring conductor layer opposed thereto. Wherein the thickness of the insulating layer is thicker than the thickness of the other insulating layers. According to the multilayer wiring board of the present invention, since the thickness of the insulating layer between the connection land and the wiring conductor layer facing the connection land is larger than the other insulating layers, the connection land and the wiring conductor facing the connection land are thicker. Since the capacitance between the layers becomes smaller, the electromagnetic coupling between the connection land and the wiring conductor layer becomes smaller,
It is possible to prevent occurrence of characteristic impedance mismatch in the connection land. Further, since no opening is formed in the wiring conductor layer, it is possible to prevent the resistance value and the inductance value of the wiring conductor layer from increasing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a multilayer wiring board according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of a multilayer wiring board according to the present invention. In FIG. 1, 1 is a multilayer wiring board, 2 is an insulating base, and a through conductor 3 is formed on the insulating board 2. Furthermore, connection lands 4 extending from the through conductors 3 are formed on the surface of the insulating base 2, and constitute a core substrate 5. The inside of the through conductor 3 is filled with an insulating material or a conductive material 6, a plurality of insulating layers 7 and a plurality of wiring conductor layers 8 are formed on the surface of the core substrate 5, and one surface has External connection pads 9 for electrical connection are formed, and are electrically connected to the connection lands 4 by a plurality of via conductors 10. Further, a semiconductor element connection pad 11 is formed on the other surface, and the connection land 4 is formed by a plurality of via conductors 10.
Is electrically connected to In this example, a semiconductor element 12 such as a microprocessor or an ASIC is mounted on the upper surface of the multilayer wiring board 1, and a conductor bump 13 and a semiconductor element 12 made of solder such as tin (Sn) -lead (Pb) are used. It is electrically connected to the multilayer wiring board 1 through the connection pads 11 for connecting semiconductor elements. In these figures, the wiring conductor layer 8 is formed of a wide area pattern for ground wiring or power supply wiring, and the connection lands 4 are formed of a wide area pattern of the wiring conductor layer 8.
Are formed opposite to each other. Here, it is desirable that the connection land 4 is designed so that its characteristic impedance becomes, for example, 50Ω by electromagnetic coupling with the wiring conductor layer 8. If the characteristic impedance of the connection land 4 is different from the characteristic impedance of the through conductor 3 or the via conductor 10, mismatching of the characteristic impedance causes reflection noise. In the present invention, the thickness of the insulating layer 7a between the connection land 4 and the wiring conductor layer 8 opposed thereto in FIG. 1 is made larger than the thickness of the other insulating layers 7. As a result, the capacitance of the insulating layer 7a between the connection land 4 and the wiring conductor layer 8 facing the connection land 4 is reduced, and electromagnetic coupling between the connection land 4 and the wiring conductor layer 8 can be reduced. It is possible to prevent characteristic impedance mismatching at the connection land 4. Only the thickness of the insulating layer 7a between the connection land 4 and the wiring conductor layer 8 facing the connection land 4 is different from that of the other insulating layer 7
It is important that the thickness is larger than If the thickness of not only the insulating layer 7a but also all of the insulating layers is large, the thickness of the insulating layer 7 sandwiching the wiring conductor layer 8a, which is a signal line, becomes large. Reflection occurs due to the matching. The thickness of the insulating layer 7a is larger than the thickness of the insulating layer 7.
If the value is larger than 10%, the above-mentioned effect becomes more remarkable, so that it is good. If the difference between the thickness of the insulating layer 7a and the thickness of the insulating layer 7 is less than 10%, the effect of reducing the electromagnetic coupling between the connection land 4 and the wiring conductor layer 8 is small. Here, a conventional multilayer wiring board will be described in detail with reference to the accompanying drawings. FIG. 2 is a sectional view showing an example of a conventional multilayer wiring board. In this figure, 51 is a multilayer wiring board, 52 is an insulating base, and a through conductor 53 is formed on the insulating board 52. Further, connection lands 54 extending from the through conductors 53 are formed on the surface of the insulating base 52, and constitute a core substrate 55. Further, the inside of the through conductor 53 is filled with an insulating material or a conductive material 56, a plurality of insulating layers 57 and a plurality of wiring conductor layers 58 are formed on the surface of the core substrate 55, and one surface is External connection pads 59 for electrical connection are formed, and are electrically connected to the connection lands 54 by a plurality of via conductors 60. A semiconductor element connection pad 61 is formed on the other surface, and is electrically connected to the connection land 54 by a plurality of via conductors 60. In this example, a semiconductor element 62 such as a microprocessor or an ASIC is mounted on the upper surface of the multilayer wiring board 51, and a conductor bump 63 and a semiconductor element 62 made of solder such as tin (Sn) -lead (Pb) are used. It is electrically connected to the multilayer wiring board 51 via the semiconductor element connection pads 61 for connection. The wiring conductor layer 58 is formed of a wide area pattern for ground wiring or power supply wiring, and the connection land 54 is formed to face the wiring conductor layer 58 of the wide area pattern. In the conventional multilayer wiring board 51, the connection lands 54
The thickness of the insulating layer 57a between the insulating layer 57a and the wiring conductor layer 58 opposed thereto is usually the same as the thickness of the other insulating layers 57 because it is not particularly considered. In this case, if the thickness of the insulating layer 57a is small, the capacitance between the connection land 54 and the wiring conductor layer 58 facing the connection land 54 is large, and the electromagnetic coupling between the connection land 54 and the wiring conductor layer 58 causes the connection land. 4, the characteristic impedance mismatch occurs. If the thicknesses of the insulating layer 57 and the insulating layer 57a are both large, the wiring layer 58a as a signal line is sandwiched between the thick insulating layers 57, and reflection occurs due to mismatching of characteristic impedance. These problems are particularly problematic in a multilayer wiring board on which a semiconductor element operating at a high speed of 1 GHz or higher is mounted. In the multilayer wiring board of the present invention, a similar wiring structure may be further laminated in multiple layers to form a multilayer wiring board. Further, a multilayer wiring board may be constructed by attaching a chip resistor, a thin film resistor, a coil inductor, a cross inductor, a chip capacitor or an electrolytic capacitor, or the like. The shape of each insulating layer in plan view is as follows:
The shape may be a square, a rectangle, a diamond, a hexagon, an octagon, or the like. The multi-layer wiring board of the present invention includes a package for storing electronic parts such as a package for storing semiconductor elements, a substrate for mounting electronic parts, a so-called multi-chip module or multi-chip on which a number of semiconductor elements are mounted. Used as a package or motherboard. In the multilayer wiring board of the present invention, each insulating layer 7 is made of, for example, polyimide, epoxy resin, fluororesin,
Aluminum oxide sintered body, aluminum nitride sintered body, silicon carbide based sintered body, silicon nitride based sintered body using an organic insulating material such as polynorbornene or benzocyclobutene or by a ceramic green sheet laminating method. Insulating material using inorganic insulating material such as ceramic, mullite sintered body or glass ceramic sintered body, or combining inorganic insulating powder such as ceramic powder with thermosetting resin such as epoxy resin Formed using an electrically insulating material. As described above, the insulating layer 7a is preferably formed using a material having a thickness of 10% or more than that of the insulating layer 7.
For example, if the insulating layer 7 is made of an epoxy resin,
The thickness of the insulating layer 7a may be made of the same material. These insulating layers 7, 7a are manufactured as follows. For example, in the case of an epoxy resin, an organic material is generally provided on the upper surface of an insulating layer made of a glass epoxy resin or the like formed by impregnating a ceramic or glass fiber woven fabric of an aluminum oxide sintered body with an epoxy resin. An insulating layer 7 made of an organic resin such as an epoxy resin formed by applying a resin precursor by a coating technique such as a spin coating method or a curtain coating method and subjecting the same to a thermosetting treatment, and copper by an electroless plating method. It is manufactured by alternately stacking thin film wiring conductor layers 8 formed by employing a thin film forming technique such as a vapor deposition method and a photolithography technique, and heating and curing at a temperature of about 170 ° C. By changing the thickness of the organic resin precursor in the process of spin coating or curtain coating, it is possible to form the insulating layer 7a thicker than the other insulating layers 7. In the case of a film type resin, the insulating layer 7a having a large thickness can be formed by changing the thickness of a film to be used or by stacking a plurality of the same films. In the case of a glass ceramic sintered body, for example, an organic binder, a solvent, etc. suitable for a raw material powder composed of, for example, a glass powder composed of borosilicate glass and a ceramic filler powder composed of zirconium oxide are used. Is added and mixed to form a slurry, which is formed into a sheet by employing a conventionally known doctor blade method, thereby obtaining a glass ceramic green sheet for the insulating layer 7. In the doctor blade method, the thickness of the insulating layer 7 can be changed by changing the height of the blade, and the thickened insulating layer 7a can be easily obtained. Then, a metal paste for forming each wiring conductor layer 8 is printed and applied in a predetermined pattern, and a glass ceramic green for the insulation layer 7a is formed at a position to be an insulation layer between the connection land 4 and the wiring conductor layer 8 opposed thereto. The sheets are laminated one above the other so that they are positioned, and finally, the laminate is fired in air or a nitrogen atmosphere at a temperature of about 850 to 1100 ° C. The thickness of the insulating layer 7 is appropriately set according to the characteristics of the material to be used so as to satisfy the conditions such as mechanical strength and electrical characteristics corresponding to required specifications. Each wiring conductor layer 8 is made of, for example, tungsten (W), molybdenum (Mo), molybdenum manganese (Mo-Mn), copper (Cu), silver (Ag), silver palladium (Ag-Pd), or the like. Metal powder metallization or thin film of metal material such as copper (Cu), silver (Ag), nickel (Ni), chromium (Cr), titanium (Ti), gold (Au) or niobium (Nb) or alloys thereof May be formed. Specifically, for example, in the case of forming a thin film of a metal material, after forming a metal film by a sputtering method, a vacuum evaporation method or a plating method, it can be formed into a predetermined wiring pattern by a photolithography method. On the other hand, in the case of forming by metal powder metallization, a metal paste obtained by adding and mixing an appropriate organic binder, a solvent and the like to the metal powder is printed and applied in a predetermined pattern on a ceramic green sheet serving as the insulating layer 7. It can be formed by firing this together with the laminate of ceramic green sheets. It should be noted that the present invention is not limited to the above-described embodiment, and various changes may be made without departing from the spirit of the present invention. According to the multilayer wiring board of the present invention,
A multi-layer comprising a core substrate having a through conductor penetrating the insulating substrate and a connection land extending from the through conductor on the surface of the insulating substrate, and a plurality of insulating layers and a plurality of wiring conductor layers laminated on the surface of the core substrate By having a wiring portion and having no opening in the wiring conductor layer, the thickness of the insulating layer between the connection land and the wiring conductor layer opposed thereto is made thicker than the thickness of the other insulating layers. In addition, the electromagnetic coupling between the connection land and the wiring conductor layer is reduced, and it is possible to prevent the occurrence of characteristic impedance mismatch at the connection land. As a result, according to the present invention, it is possible to reduce the characteristic impedance mismatch at the connection between the signal wiring conductor and the signal through conductor and reduce the simultaneous switching noise. A multilayer wiring board suitable for an electronic circuit board or the like on which an electronic component such as a semiconductor element is mounted can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an example of an embodiment of a multilayer wiring board of the present invention. FIG. 2 is a sectional view showing an example of an embodiment of a conventional multilayer wiring board. [Description of Signs] 1: Multilayer wiring board 2: Insulating base 3: Through conductor 4: Connection land 5: Core substrate 7: Insulating layer 7a: Insulating layer 8 between the connecting land and the wiring conductor layer opposed thereto: Wiring conductor layer

Claims (1)

Claims: 1. A core substrate having an insulating base, a through conductor penetrating the insulating base, and a connection land extending from the through conductor on a surface of the insulating base, and the core substrate. A plurality of insulating layers and a plurality of wiring conductor layers laminated on the surface of the multi-layer wiring portion, wherein the thickness of the insulating layer between the connection land and the wiring conductor layer opposed thereto is different from that of the other insulating land. A multilayer wiring board characterized by being thicker than a layer thickness.