JP3199563B2 - Wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board used for a hybrid integrated circuit device, a semiconductor device housing package for housing a semiconductor device, and the like.

[0002]

2. Description of the Related Art Conventionally, a wiring board, for example, a wiring board used for a semiconductor element housing package for housing a semiconductor element is generally made of an electrically insulating material such as an aluminum oxide sintered body, and has a substantially upper central portion. And a plurality of metallized wiring layers (a metallized wiring layer for signal, a metallized wiring layer for power supply, and a metallized wiring layer for grounding) were attached and derived from the periphery to the outer periphery of the concave portion. The semiconductor element is bonded and fixed to the bottom surface of the concave portion of the insulating base via an adhesive, and each electrode (signal electrode, power supply electrode, and ground electrode) of the semiconductor element is metalized via a bonding wire. Then, a lid is bonded to the upper surface of the insulating base via a sealing material such as glass or resin, and then the insulating base and the lid are connected to each other. A semiconductor device as a product in a container inside made by sealing a semiconductor element hermetically.

[0003] The insulating substrate made of the aluminum oxide sintered body or the like is generally made of alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), magnesia (Mg
O) or the like, an appropriate organic solvent and a solvent are added and mixed to form a slurry, and a ceramic green sheet (green ceramic sheet) is formed by employing a conventionally known doctor blade method or calender roll method. Then, the ceramic green sheet is manufactured by subjecting the ceramic green sheet to appropriate punching, laminating a plurality of sheets, and firing at a high temperature (about 1600 ° C.). The metallized wiring layer is made of tungsten, molybdenum, manganese, etc. A ceramic green sheet to be used as an insulating substrate by employing a thick film forming technique such as a screen printing method using a metal paste obtained by adding and mixing an appropriate organic solvent and a solvent to the high melting point metal powder. Is formed from the periphery of the concave portion of the insulating base to the outer peripheral portion by printing and coating in advance. .

However, the wiring board used in the conventional package for accommodating a semiconductor element is provided with a metallized wiring layer provided on an insulating base, which is used to reduce the attenuation of a signal in which the impedance of the signal metallized wiring layer in which an electric signal propagates propagates. Generally, the impedance is set to 50 to 100Ω to minimize the difference, which is largely different from the input impedance (several Ω) and the output impedance (several MΩ) of the semiconductor element. Therefore, when an electric signal is input / output to / from the semiconductor element through the signal metallization wiring layer, the characteristic (input / output) impedance of the semiconductor element is mismatched with the impedance of the signal metallization wiring layer viewed from the semiconductor element side. However, there is a drawback that noise due to reflection is generated in an electric signal transmitted through the metallized wiring layer for use, and the noise is input to the semiconductor element and the semiconductor element cannot be normally operated.

In order to solve the above drawbacks, a signal metallized wiring layer to which a signal electrode of a semiconductor element is connected and a power metallized wiring layer or a ground metallized wiring layer to which a power supply electrode or a ground electrode of a semiconductor element is connected. A terminating resistor composed of a thin film resistor is attached and connected between them, and the characteristic impedance of the semiconductor element and the impedance of the signal metallization wiring layer are matched, and noise due to reflection is generated in the electric signal propagating through the signal metallization wiring layer. And a gap is formed in each signal metallization wiring layer, and a damping resistor made of a thin film resistor is connected in series to the gap, and the difference between the impedance of the signal metallization wiring layer and the characteristic impedance of the semiconductor element. The noise generated due to the noise is attenuated by the damping resistor, and the noise is So as to prevent from entering the semiconductor element propagates through the rise wiring layer.

The thin-film resistor as the terminating resistor or the damping resistor is generally made of a material having an electrical resistivity of 100 to 150 μΩcm, such as tantalum nitride or nickel-chromium, and is formed by a sputtering method, an ion plating method, and a photolithography technique. By adopting a thin film forming technique such as that described above, it is possible to cover the gap between the metallized wiring layer for signal and the metallized wiring layer for power supply or the grounded metallized wiring layer on the surface of the insulating substrate, or the gap provided in each metallized wiring layer for signal. Be worn.

The thin film resistor applied to the surface of the insulating base is partially connected to the metallized wiring layers for signal, power supply and ground for reliable and strong electrical connection. It extends toward the upper surface and has a large bonding area with each metallized wiring layer.

[0008]

However, the wiring board on which the terminating resistor and the damping resistor made of the thin film resistor are applied has a metallized wiring layer for signal, power and ground, which is a thick film such as screen printed. While the thin-film resistor is formed by a thin-film forming technique such as sputtering or vapor deposition, it has the following disadvantages, whereas the thin-film resistor is formed by a forming technique.

In other words, a wiring substrate having a terminating resistor formed of a thin film resistor attached thereto will be described as an example. (1) Insulation between an adjacent signal metallization wiring layer and a power metallization wiring layer or a ground metallization wiring layer When a thin film resistor is applied on a substrate by a thin film forming technique such that a part of the thin film resistor extends and joins from the side surface to the upper surface of the metallized wiring layers, the metallized wiring layers are formed by a thick film forming technique, Is 10 to 20 μm, the resistance material to be a thin film resistor is hardly penetrated into the intersection between the lower side surface of both metallized wiring layers and the upper surface of the insulating substrate, and as a result, the thin film resistor Although the thickness of the thin film resistor is 0.1 μm to 0.5 μm, the thickness of the thin film resistor attached to the intersection of the side surface of both metallized wiring layers and the upper surface of the insulating substrate is 0.01 μm and 1/10 or less. It will be extremely thin below. Therefore, when heat or the like generated when the semiconductor element is operated is applied to the wiring board, a stress is generated between the insulating base, the metallized wiring layer and the thin-film resistor due to a difference in their respective thermal expansion coefficients. At the position where the lower side surface of the thin film resistor and the upper surface of the insulating substrate intersect, the thin film resistor is concentrated in a thin region, and the thin film resistor is electrically disconnected due to cracks, and the function as a terminating resistor is lost.

(2) Since the metallized wiring layers for signal, power, and ground applied on the insulating base are formed by a thick film forming technique such as a screen printing method, their line widths are increased. In addition, the line length has a variation of about 10 μm, and the distance between the signal metallization wiring layer and the power supply or ground metallization wiring layer also has a large variation. Therefore, for example, even when a thin-film resistor as a terminating resistor is formed between the signal metallization wiring layer and the power-supply metallization wiring layer, the length of the thin-film resistor is not constant, and the resistance value varies. The impedance of the signal metallization wiring layer cannot be accurately matched to the characteristic impedance of the semiconductor element. If an electric signal is still propagated to the signal metallization wiring layer, noise due to the impedance mismatch occurs. .

The above-mentioned disadvantage has been described by taking the case where a thin-film resistor is used as a terminating resistor as an example. However, the same disadvantage occurs when the thin-film resistor is used as a damping resistor.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a method of disconnecting a thin-film resistor having a predetermined electric resistance between thick-film metallized wiring layers attached to an insulating substrate. It is an object of the present invention to provide a wiring board which can be firmly connected without being attached.

[0013]

According to the present invention, there is provided a wiring board having a plurality of thick metallized wiring layers deposited on an upper surface of an insulating base, and an insulating layer between adjacent thick metallized wiring layers having a thickness of 10 to 20 μm. A wiring substrate in which a thin film resistor having a thickness of 0.1 to 0.5 μm is adhered to the upper surface of the base by a thin film forming technique so that a part thereof extends and joins from the side surface to the upper surface of each thick film metallized wiring layer. The thin film resistor has, on its surface, two regions in which the thickness of the thin film resistor facing the intersection of at least each side surface of the adjacent thick film metallized wiring layer and the upper surface of the insulating base is thin. And said
Each of the adjacent thick metallized wiring layers is connected to a thin film resistor.
, And two cover electrodes each having a thickness of 0.5 μm or more are attached with an interval between them.

[0014]

According to the wiring board of the present invention, on the surface of the thin film resistor, at least the thin film opposing the intersection of each side surface of the thick metallized wiring layer having a thickness of 10 to 20 μm and the upper surface of the insulating substrate. In the two regions where the thickness of the resistor is thin, a thin film resistor is placed on each of the adjacent thick metallized wiring layers.
Since two cover electrodes each made of a conductive material for electrical connection and having a thickness of 0.5 μm or more are applied with a space between them, the side surface of the thick metallized wiring layer and the insulating substrate Even at the position where the upper surface intersects, even if a stress is applied to a region where the thickness of the thin-film resistor is thin, a stress caused by a difference in thermal expansion coefficient between the thin-film resistor, the thick metallized wiring layer and the insulating base is applied, and a crack occurs, The thin-film resistor is secured to each of the thick metallized wiring layers by a cover electrode made of conductive material.
Since the electrical connection is actually made, there is no electrical disconnection. Even if the interval between the thick metallized wiring layers varies, by setting the interval between the two cover electrodes to a predetermined interval, the resistance of the thin film resistor can be reduced. The value can be a predetermined value.

Therefore, when this wiring board is used for a package for housing a semiconductor element and a thin film resistor is used as a terminating resistor, the impedance of the thick metallized wiring layer for signals accurately matches the characteristic impedance of the semiconductor element. ,
There is almost no noise due to reflection in the electric signal transmitted through the thick metallized wiring layer for signals, and when used as a damping resistor, the noise propagating through the thick metallized wiring layer is effectively attenuated by the damping resistor. As a result, unnecessary noise does not enter the semiconductor element, and the semiconductor element can always be normally operated.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a case where the wiring board of the present invention is used for a semiconductor device housing package for housing a semiconductor device will be described as an example.

FIGS. 1, 2 and 3 show an embodiment of a package for housing a semiconductor element using a wiring board according to the present invention.
Is an insulating base, and 2 is a lid. The insulating base 1 and the lid 2
Thus, the container 4 for housing the semiconductor element is configured.

The insulating substrate 1 is provided with a recess 1a for accommodating the semiconductor element 3 at a substantially central portion of the upper surface thereof, and the semiconductor element 3 is provided with an adhesive such as resin, glass, brazing material or the like on the bottom of the recess 1a. It is placed and fixed via

The insulating substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, and a glass ceramic sintered body. When it is made of an aluminum oxide sintered body, alumina (Al ₂ O ₃ ), silica (Si
O _2), calcia (CaO), employing a magnesia (MgO) well-known doctor blade method or calendar roll method this with raw material powder in a suitable organic solvent, the solvent was admixed makes with mud漿状such like Forming a ceramic green sheet (ceramic green sheet)
Thereafter, the ceramic green sheet is subjected to an appropriate punching process, and a plurality of the green sheets are laminated.
(0 ° C.).

A plurality of metallized wiring layers 5 (metallized wiring layers for signal, metallized wiring layers for power supply and metallized wiring layers for grounding) are formed on the insulating substrate 1 so as to extend from the periphery to the outer periphery of the recess 1a. Each electrode (signal electrode, power supply electrode, and ground electrode) of the semiconductor element 3 is electrically connected to the peripheral portion of the concave portion 1a of the metallized wiring layer 5 via a bonding wire 6, and at a portion led out to the outer periphery. The external lead terminal 7 connected to an external electric circuit is attached via a brazing material such as silver brazing.

The metallized wiring layer 5 functions to electrically connect each electrode of the semiconductor element 3 to the external lead terminal 7, and uses a thick film forming technique, that is, tungsten, molybdenum,
A concave portion of the insulating substrate 1 is obtained by previously printing and applying a metal paste obtained by adding a suitable organic solvent and a solvent to a high melting point metal powder such as manganese to a ceramic green sheet serving as the insulating substrate 1 by screen printing or the like. 1a is formed from the periphery to the outer periphery.

The metallized wiring layer 5 is formed by plating a metal having good conductivity and excellent corrosion resistance, such as nickel and gold, on the exposed surface to a thickness of 1.0 to 20.0 μm by plating. By doing so, oxidation corrosion of the metallized wiring layer 5 can be effectively prevented, and the connection between the metallized wiring layer 5 and the bonding wire 6 and the brazing between the metallized wiring layer 5 and the external lead terminals 7 are extremely strong. I can do it. Therefore, in order to prevent the metallized wiring layer 5 from being oxidized and corroded, and to firmly connect the metallized wiring layer 5 to the bonding wires 6 and braze the metallized wiring layer 5 to the external lead terminals 7, 1.0 to 2 nickel, gold, etc. on the exposed surface
It is preferable that the layer is deposited to a thickness of 0.0 μm.

The insulating substrate 1 on which the plurality of metallized wiring layers 5 are adhered is formed on the upper surface of the insulating base 1 and the signal metallized wiring layer 5a to which the signal electrode and the power supply electrode of the semiconductor element 3 are electrically connected. The thin film resistor 8 is formed between the thin film resistor 8 and the power supply metallized wiring layer 5b.
Is electrically connected between the metallization wiring layer 5a for signal and the metallization wiring layer 5b for power supply, so that the impedance of the metallization wiring layer 5a for signal matches the characteristic impedance of the semiconductor element 3, whereby the metallization wiring layer 5a for signal is used. No noise due to reflection is generated in the electric signal propagating through.

The thin film resistor 8 is made of tantalum nitride, nickel-chromium, nickel-chromium-silicon, tantalum silicate, or the like, and is adjacent to the upper surface of the insulating substrate 1 by a thin film forming technique such as a sputtering method or an ion plating method. Between the metallization wiring layer for signal 5a and the metallization wiring layer for power supply 5b, part of both metallization wiring layers 5a, 5b
Is attached to a thickness of about 0.1 to 0.5 μm so as to extend and join from the side surface to the upper surface.

When the thin film resistor 8 is formed of tantalum nitride, the tantalum nitride has good bonding properties with the insulating base 1 and the metallized wiring layers 5a and 5b for signal and power supply.
In addition, since the change in the electrical resistance value with respect to the temperature change is small, the thin film resistor 8 can be securely and firmly connected between the signal metallization wiring layer 5a and the power metallization wiring layer 5b,
At the same time, there is no variation in the electric resistance value due to the temperature change. Therefore, it is preferable that the thin film resistor 8 is formed of tantalum nitride.

As shown in FIG. 3, the thin film resistor 8 has two surfaces opposed to the intersection A between at least the side surfaces of the signal and power metallization wiring layers 5a and 5b and the upper surface of the insulating substrate 1 as shown in FIG. In the region, two cover electrodes 9 made of a conductive material and having a thickness of 0.5 μm or more are attached with an interval therebetween.

The cover electrode 9 functions to reliably connect the thin film resistor 8 between the signal and power metallization wiring layers 5a and 5b, and is generated when the semiconductor element 3 is operated. Heat is applied to the thin film resistor 8, the signal and power supply metallized wiring layers 5a and 5b, and the insulating base 1,
The stress resulting from the difference between the respective thermal expansion coefficients acts on the region where the thickness of the thin film resistor 8 is thin at the position where the side surfaces of the signal and power metallization wiring layers 5a, 5b intersect with the upper surface of the insulating base 1, Even if the thin film resistor 8 is broken by cracks, the broken wire is reconnected by the cover electrode 9 made of a conductive material adhered to the surface of the thin film resistor 8, and as a result, the thin film resistor The body 8 always includes the signal metallization wiring layer 5a and the power metallization wiring layer 5b.
A predetermined electrical resistance value is connected between them.

The cover electrode 9 is made of, for example, nichrome (nickel-chromium) -gold, titanium-tungsten, copper, gold or the like having an electric resistivity of 60 μΩcm or less, more preferably 1 μm or less.
It is formed of a conductive material of 0 μΩcm or less, and at least the signal and power metallization wiring layers 5 a, 5 a on the surface of the thin film resistor 8 are formed by vapor deposition, sputtering, plating or the like.
b are attached to two regions facing the intersection A between each side surface and the upper surface of the insulating base 1.

The cover electrode 9 has a thickness of 0.5.
If it is less than μm, the mechanical strength of the cover electrode 9 decreases,
When a break occurs in the thin-film resistor 8 due to a crack, a break also occurs in the cover electrode 9 and the thin-film resistor 8 can be reliably electrically connected between the signal and power metallization wiring layers 5a and 5b. Disappears. Therefore, the thickness of the cover electrode 9 is specified to be 0.5 μm or more.

The cover electrode 9 has a thickness of 20 μm.
When the thickness exceeds m, there is a possibility that the cover electrode 9 may peel off between the cover electrode 9 and the thin film resistor 8 due to the stress at the time of applying the cover electrode 9 to the thin film resistor 8. It is preferable to set the thickness to 20 μm or less.

Further, when the cover electrode 9 has a two-layer structure of a nickel-chromium layer and a gold layer, the nickel-chromium layer is composed of both tantalum nitride constituting the thin film resistor 8 and gold having an extremely small electric resistance. Since the bonding property is good, the cover electrode 9 having a small electric resistance value can be extremely firmly adhered on the thin film resistor 8. Therefore, it is preferable that the cover electrode 9 has a two-layer structure of a nickel-chromium layer and a gold layer and is attached to the surface of the thin film resistor 8 made of tantalum nitride.

Further, the cover electrodes 9, 9 made of two conductive materials and adhered to the surface of the thin film resistor 8 are provided with a signal metallized wiring layer 5a and a power supply The electric resistance value of the thin film resistor 8 connected between the metallizations 5b can be set to an arbitrary predetermined value. Accordingly, the distance between the metallized wiring layer 5a for signal and the metallized wiring layer 5b for power supply on the insulating substrate 1 is slightly widened in consideration of the variation, and the thin-film resistor 8 formed between the metallized wiring layers 5a and 5b also has When the electric resistance is set to be slightly higher, the thin film resistor 8 is adjusted so that the electric resistance becomes a predetermined value by the two cover electrodes 9 and 9 attached to the surface thereof. The thin film resistor 8 having a predetermined electric resistance value can always be electrically connected between the layer 5a and the power supply metallized wiring layer 5b.

On the other hand, an external lead terminal 7 is brazed to one end of each of the signal, power and ground metallized wiring layers 5 formed on the insulating base 1. 7 is a semiconductor element 3 housed inside
By connecting the external lead terminal 7 to the external electric circuit, the semiconductor element 3 housed therein is electrically connected to the external electric circuit via the metallized wiring layer 5 and the external lead terminal 7. Will be connected.

The external lead terminal 7 is ASTM F-1
5 (Fe-Ni-Co alloy) and 42 alloy (Fe-Ni
Alloy) or the like, and is formed into a predetermined plate shape by adopting a conventionally known metal working method such as a rolling method or a punching method on an ingot (lump) such as ASTM F-15.

The external lead terminal 7 is preferably formed by coating a metal having excellent corrosion resistance such as nickel and gold and having good wettability with a brazing material to a thickness of 1.0 to 20 μm on the exposed surface. Oxidative corrosion of the external lead terminal 7 can be effectively prevented, and the connection between the external lead terminal 7 and the external electric circuit can be made firm. Therefore, it is preferable that nickel, gold, or the like be layered on the exposed surface of the external lead terminal 7 to a thickness of 1.0 to 20 μm.

Thus, in the semiconductor device housing package using the wiring board of the present invention, the semiconductor device 3 is bonded and fixed to the bottom surface of the concave portion 1a of the insulating base 1 with an adhesive such as glass, resin or brazing material. Are electrically connected to the metallized wiring layer 5 via bonding wires 6, and then the lid 2 is joined to the upper surface of the insulating base 1 with a sealing material made of glass, resin, brazing material, or the like.
A semiconductor device as a product is obtained by housing the semiconductor element 3 in an airtight manner inside a container 4 including the insulating base 1 and the lid 2.

In the above-described embodiment, the thin-film resistor 8 is connected between the signal metallization wiring layer 5a and the power supply metallization wiring layer 5b, and the terminator for matching the impedance of the signal metallization wiring layer to the characteristic impedance of the semiconductor element. The case of using as a resistor has been described as an example, but the present invention can also be applied to a case where this is used as a damping resistor connected to a signal metallization wiring layer.

[0038]

According to the wiring substrate of the present invention, on the surface of the thin-film resistor, at least the adjacent side surfaces of the thick metallized wiring layer having a thickness of 10 to 20 μm and the upper surface of the insulating substrate. A thin-film resistor adjacent to a thick-film metallization in two regions where the thickness of the thin-film resistor facing the intersection is reduced.
Since two cover electrodes each made of a conductive material for electrical connection to each of the wiring layers and having a thickness of 0.5 μm or more are applied with a space between them, the side surfaces of the thick metallized wiring layers and At the position where the upper surface of the insulating substrate intersects, it is assumed that a stress is applied to a region where the thickness of the thin film resistor is thin due to a difference in thermal expansion coefficient between the thin film resistor, the thick metallized wiring layer, and the insulating substrate, and a crack is generated. Also, the thin-film resistor is made of a thick metallized wiring layer by a cover electrode made of conductive material .
Since each of the thick metallized wiring layers is electrically connected to each other, no electrical disconnection occurs, and even if the gap between the thick film metallized wiring layers varies, the gap between the two cover electrodes is set to a predetermined distance, whereby the thin film resistor is formed. The resistance value of the body can be set to a predetermined value.

Therefore, when this wiring board is used for a package for accommodating a semiconductor element and a thin film resistor is used as a terminating resistor, the impedance of the thick film metallized wiring layer for signals accurately matches the characteristic impedance of the semiconductor element. ,
There is almost no noise due to reflection in the electric signal transmitted through the thick metallized wiring layer for signals, and when used as a damping resistor, the noise propagating through the thick metallized wiring layer is effectively attenuated by the damping resistor. As a result, unnecessary noise does not enter the semiconductor element, and the semiconductor element can always be normally operated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment in which a wiring board of the present invention is applied to a package for housing a semiconductor element.

FIG. 2 is a plan view of an insulating base of the package for housing a semiconductor element shown in FIG. 1;

FIG. 3 is an enlarged sectional view of a round part of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 2 ... Lid 3 ... Semiconductor element 4 ... Container 5 ... Metallized wiring layer 8 ... Thin film resistor 9 ... Cover electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 1/16 H05K 3/24

Claims (3)

(57) [Claims] 1. A technique for forming a plurality of thick metallized wiring layers on an upper surface of an insulating substrate and forming a thin film on an upper surface of the insulating substrate between adjacent thick metallized wiring layers having a thickness of 10 to 20 μm.
The thin film resistor of a thickness of 0.1 to 0.5 [mu] m, a wiring substrate having deposited so that a part is extended junction toward the upper surface from the side of the thick-film metallized wiring layer by the thin-film resistor at its surface, wherein at least adjacent the thin film resistor opposite to the intersection of the respective side surface and the insulating substrate upper surface of the thick film metallized wiring layer thickness becomes in two has a thin region, the thin film resistor The adjacent thick metallization
A wiring substrate, comprising two cover electrodes each made of a conductive material for making an electrical connection to each of the wiring layers and having a thickness of 0.5 μm or more with a gap therebetween. 2. A thin film resistor comprising tantalum nitride,
The wiring board according to claim 1, wherein the cover electrode has a two-layer structure of a nickel-chromium alloy layer and a gold layer. 3. The wiring substrate according to claim 1, wherein the cover electrode made of the conductive material has an electric resistivity of 60 μΩcm or less.