JP2566793B2 - Multilayer wiring board - Google Patents

Description

The present invention relates to a multilayer wiring board on which a semiconductor integrated circuit element that operates by a high frequency electric signal is mounted.

[Conventional technology]

Conventionally, a multilayer wiring board on which a semiconductor integrated circuit device is mounted has a conductive sheet made of a refractory metal such as tungsten (W) screened on the surface of a green sheet made of alumina (Al ₂ O ₃ ) having excellent electric insulation. A multilayer wiring board was obtained by printing thick films by a printing method, then sequentially laminating these and firing them simultaneously to form electric wiring.

However, in recent years, hybrid ICs and LSIs
In order to further increase the density of the semiconductor integrated circuit device and the rapid progress of high integration in order to further increase the mounting density of the substrate, in the conventional multi-layer wiring board with thick film, the conductive pattern of There is a problem that miniaturization is difficult, and the total thickness becomes thick, making it difficult to form multiple layers, and it is not possible to achieve sufficient densification and high functionality. Another problem of the prior art is that ceramics such as alumina used for the substrate has a high dielectric constant of, for example, about 10, which makes it difficult to propagate a signal at high speed in combination with the resistance component in the circuit. There is a problem that the high speed operation of the device becomes impossible.

Therefore, in order to solve the above-mentioned drawbacks of the conventional multilayer wiring board, for example, a dielectric constant of 3 to 3.
Forming an insulating film such as 5 which is relatively small with polyimide resin,
A conductive layer for electric wiring is thinned on the insulating film by using a thin film forming technique such as a vapor deposition method and a sputtering method, and a fine conductive pattern is formed by photolithography. It has been attempted to obtain a multi-layer wiring board which enables high-speed operation of a semiconductor integrated circuit device with high density and high function by making the multi-layer structure.

However, in this multilayer wiring board, when the semiconductor integrated circuit element is operated by a high-frequency electric signal, the circuit wirings are closely arranged closely to each other, so that the voltage change on one circuit wiring is caused to the other circuit wirings. The so-called crosstalk noise that induces noise is generated, and further, the electrical signal is reflected due to the mismatch of the characteristic impedance between the semiconductor integrated circuit element and the multilayer wiring board, and the interference between the semiconductor integrated circuit element and the circuit wiring and There is a problem that distortion of signal propagation occurs.

Therefore, in order to solve the above problems, it has been proposed to provide an electric resistor in the vicinity of a lead pin connecting the multilayer wiring board to an external electric circuit or on a pad on the surface of the multilayer wiring board to serve as a terminating resistor. There is.

[Problems to be solved by the invention]

However, when the electric resistor is provided in the vicinity of the lead pin of the multilayer wiring board, the circuit wiring connecting the electric resistor and the semiconductor integrated circuit element mounted on the multilayer wiring board becomes long in distance. Therefore, it is still insufficient for reducing crosstalk noise and propagating a high-frequency electric signal without distortion, and even when the electric resistor is provided on the surface pad of the multilayer wiring board, the above-mentioned crosstalk is generated. Since the noise and the distortion of the high frequency electric signal are not eliminated and the multilayer wiring board cannot be downsized, there is a problem that it cannot be a high density / integrated multilayer wiring board for high speed signal propagation. It was

[Object of the Invention]

The present invention has been devised in view of the above-described drawbacks, and an object thereof is to match the characteristic impedances of the semiconductor integrated circuit element and the multilayer wiring board, reduce crosstalk noise, and distort high-frequency electrical signals. An object of the present invention is to provide a multi-layer wiring board which is capable of propagation and has a high density and high integration for further high-speed signal propagation.

[Means for solving problems]

The present invention relates to a multilayer wiring board in which an interlayer insulating film made of a polymeric material and a main conductor are sequentially provided on the surface of an insulating substrate and the main conductor is embedded in the interlayer insulating film. The thin film electric resistor is provided in contact with the body.

In the present invention, a thin-film electric resistor is provided in contact with the main conductor, and the electric resistor is built in the multilayer wiring board, so that the circuit wiring between the electric resistor and the mounted semiconductor integrated circuit element is separated by distance. Is extremely short, the inductance of the connection portion of the electric resistor as a terminating resistor is small, and the electric resistor is formed as a thin film on the interlayer insulating film, so that the reproducibility of the resistance value of the electric resistor is improved. Since it is good and the like, it is possible to propagate a high-frequency electric signal without distortion at a high speed, and it is possible to obtain a multilayer wiring board with higher density and higher integration.

〔Example〕

Next, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the multilayer wiring board of the present invention.

In FIG. 1, reference numeral 1 denotes an insulating base made of mullite ceramics or the like. The upper surface of the insulating base 1 is coated with a polymer material such as polyimide resin by spin coating, roll coating, or the like, and then heat treatment is performed to form an insulating film. Form 2.

Then, after forming a thin film of copper (Cu) / aluminum (Al) or gold (Au) by a sputtering method or the like, the main conductor 3 is formed by photolithography, and a resistor such as a tantalum compound is similarly formed on the main conductor 3. The material and the main conductor material such as copper are sequentially formed into a film by a sputtering method or the like, and thereafter,
The electric resistor 4 and the main conductor 5 are formed by photolithography. Further, by coating the polymer material such as the polyimide resin on the insulating film 6 and forming the insulating film 6, a multilayer wiring board having a built-in thin film electric resistor can be obtained.

FIG. 2 is a sectional view showing another embodiment of the multilayer wiring board of the present invention, in which 1 is an insulating base made of mullite ceramics or the like, and the upper surface of the insulating base 1 is made of a polymer material such as polyimide resin. An insulating film 2 is formed, and an electric resistor 4 made of a tantalum compound and a main conductor 5 made of copper are formed on the upper surface of the insulating film 2 in the same manner as described above. The insulating film 6 made of the above polymer material is formed to form a multi-layer wiring board having a built-in thin film electric resistor.

The polymer material used as the interlayer insulating film of the multilayer wiring board of the present invention is preferably polyimide resin, silicone resin, polybutadiene resin, polyamideimide resin, polytetrafluoroethylene resin, or the like.

Further, the material used as the thin film electric resistor is a nickel-chromium compound such as NiCr, NiCrSi, NiCrSiO, NiCrAlSi, etc., which has a sheet resistance of 30 to 400 Ω by the four-point probe method within a film thickness range of 100 to 10,000 Å described later. Tantalum compounds such as Ta, Ta and TaSiO ₂ , TaN and titanium compounds such as TiN and TiW are suitable.

In terms of resistance value accuracy, it is difficult to match the characteristic impedance between the semiconductor integrated circuit element and the multilayer wiring board unless the variation in resistance value is within ± 10%. For that purpose, it is desirable that the film thickness of the thin film electric resistor is 100 Å or more, and in terms of the dispersion of the resistance value, when processing a fine pattern of the thin film electric resistor by photolithography, Size,
In particular, if the processing error of the width is not less than 5 μm, the variation in the resistance value cannot fall within the range of ± 10%. For that purpose, it is desirable that the film thickness of the resistor be 10,000 Å or less.

On the other hand, in terms of adhesion between the thin film electric resistor, the base and the interlayer insulating film, when the film thickness of the resistor is less than 100 Å, JIS
By the adhesive tape test based on the regulation of Z1522, the resistor is peeled off from the underlying interlayer insulating film, and the adhesion to the interlayer insulating film becomes poor. Therefore, the film thickness is preferably 100 Å or more.

That is, the thin film electric resistor of the present invention has a film thickness of 100 to 1
It is preferably 0000Å.

[Experimental example]

Next, the function and effect of the present invention will be described based on experimental examples.

The surface of the ceramic substrate, which is made of washed 1.4 inch square mullite ceramics and has a built-in ground layer, is coated with a polymer material such as polyimide resin by the well-known spin coating or roll coating.
By heat treatment at a temperature of 0-400 ℃, the thickness of 3-50
An insulating film of μm is formed.

Next, a resistor material made of a tantalum compound and a main conductor material made of copper are sequentially formed on the entire upper surface of the insulating film, and an electric resistance film is formed by a vapor phase growth method such as a conventionally known vapor deposition method or sputtering method. After forming 1000 Å and the main conductor film to a thickness of 1 to 5 μm, a pattern for evaluation is formed by photolithography, and this is repeated in sequence, and the resistance value of the electric resistance film is set to show 50Ω. The multilayer wiring board of was obtained.

Next, using the above-mentioned evaluation board, by the time domain reflectometry (TDR method), from the step pulse generator to the signal layer of the multilayer wiring board and the ground layer of the ceramic board, one pulse of the rise time Tr shown in Table 1 was applied. Apply a signal,
The waveform of the signal was measured with an oscilloscope, the reflected noise voltage Vn was measured, and the inductance L was derived.

 The above results are shown in Table 1.

In addition, in the same manner as described above, on the insulating substrate made of mullite ceramics, by the thin film forming technique and the photolithography technique, the resistance value is provided outside the multilayer wiring substrate in which the ground layer and the signal layer are laminated via the interlayer insulating film. A conventional example is one in which a 50Ω chip resistor is connected.

As is apparent from Table 1, in the conventional example in which the electric resistor is connected to the outside of the multilayer wiring board, the reflection noise is largely generated in a high-speed signal whose rise time of one pulse from the step pulse generator is 0.5 ns or less. 300m reflection noise voltage
It is extremely high (V or more), and the inductance of the connection part of the chip resistor packaged as a terminating resistor is as large as 15 nH.

On the other hand, in the multilayer wiring board incorporating the thin film electric resistor of the present invention, the reflection noise voltage is extremely low, which indicates that almost no reflection noise is generated, the inductance is as small as 0.5 nH, and the signal rise time is low. It is possible to speed up more.

〔The invention's effect〕

As described in detail above, in a multilayer wiring board in which an interlayer insulating film made of a polymeric material and a main conductor are sequentially provided on the surface of an insulating substrate, a thin-film electric resistor is in contact with the main conductor embedded in the interlayer insulating film. Since the resistance value of the electric resistor can be obtained with high accuracy and the inductance in the connection part of the terminating resistor is small, it is possible to reduce crosstalk noise and control the characteristic impedance. It is possible to obtain a highly reliable multilayer wiring board which is capable of high density, high integration and high-speed propagation of a high frequency electric signal without distortion.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the multilayer wiring board of the present invention, and FIG. 2 is a sectional view showing another embodiment of the multilayer wiring board of the present invention. 1 ... Insulating substrate 2, 6 ... Interlayer insulating film 3, 5 ... Main conductor

Claims (1)

(57) [Claims] 1. An interlayer insulating film made of a polymer material having a relative dielectric constant of 3.5 or less and a thin film main conductor are sequentially provided on the surface of an insulating substrate,
A multilayer wiring board having a thin-film main conductor embedded in an interlayer insulating film, wherein a thin-film electrical resistor is provided in surface contact with the thin-film main conductor embedded in the interlayer insulating film. Multilayer wiring board.