JPH08307025A - Wiring board and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a wiring board capable of effectively preventing the occurrence of chipping or cracking and making the electric resistance of the wiring conductor low to reliably electrically connect a semiconductor element or the like to an external electric circuit. To provide. [Structure] An insulating substrate 1 comprising 60 to 95% by weight of an inorganic insulating powder and 5 to 40% by weight of a thermosetting resin, wherein the inorganic insulating powder is bonded by the thermosetting resin.
Metal powder with a particle size of less than 0.05 μm and particle size of 0.05 μm
The wiring conductor 2 in which the above metal powders were bonded by a thermosetting resin was applied.

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 semiconductor element housing package for housing semiconductor elements, a hybrid integrated circuit board and the like.

[0002]

2. Description of the Related Art Hitherto, as a wiring board, for example, a wiring board used in a semiconductor element housing package for housing a semiconductor element, a laminated ceramic wiring board capable of relatively high-density wiring has been widely used. This wiring board is made of ceramics such as aluminum oxide sintered body and has an insulating base having a recess for accommodating a semiconductor element in the center of the upper surface thereof, and tungsten, molybdenum, etc. led out from the periphery of the recess of the insulating base to the lower surface. And a wiring conductor made of a refractory metal powder, the semiconductor element is adhered and fixed to the bottom surface of the recess of the insulating substrate via an adhesive such as glass, resin, or brazing material, and each electrode of the semiconductor element is fixed. For example, it is electrically connected to a wiring conductor through an electrical connection means such as a bonding wire, and then a glass cover is formed on the upper surface of the insulating base so as to cover the recess of the insulating base. , A resin, a brazing material, etc., are bonded together, and the semiconductor element is hermetically housed in the recess of the base body. To become.

This conventional wiring board is generally manufactured by a ceramic green sheet laminating method. Specifically, aluminum oxide, silicon oxide, magnesium oxide,
A plurality of ceramic green sheets are obtained by adding a suitable organic binder to a ceramic raw material powder such as calcium oxide, a solvent and the like to form a slurry and making it into a sheet shape by adopting a conventionally known doctor blade method, Thereafter, the ceramic green sheet is subjected to appropriate punching processing, a metal paste to be a wiring conductor is printed and applied in a predetermined pattern, and finally the ceramic green sheets are laminated vertically in a predetermined order to form a ceramic molded body. It is manufactured by firing the ceramic green body at a high temperature of about 1600 ° C. in a reducing atmosphere.

[0004]

However, in this conventional wiring board, since the ceramics such as the aluminum oxide sintered body forming the insulating substrate have the property of being hard and brittle, an automatic line for the carrying process and the semiconductor device manufacturing is provided. Etc., when the wiring boards collide with each other or between the wiring boards and a part of the semiconductor device manufacturing automatic line, a crack, crack, crack or the like occurs in the insulating substrate, and as a result, the semiconductor element can be housed in an airtight manner. Therefore, there is a drawback that the semiconductor element cannot be operated normally and stably for a long period of time.

Further, according to the method for manufacturing a wiring board, when firing the ceramic green body, uneven firing shrinkage occurs in the ceramic green body due to the variation in the density of the ceramic raw material powder in each ceramic green sheet. There is also a drawback that the resulting wiring board is deformed due to warpage or the like and the dimensions are varied, and if the deformation or the variations are large, the wiring conductor is broken.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in view of the drawbacks of the conventional semiconductor element housing package, and its purpose is to effectively prevent the occurrence of cracks or cracks due to the application of impact force, (EN) Provided is a wiring board capable of normally and stably operating a semiconductor element housed in a container for a long period of time.

Another object of the present invention is to reduce deformation such as warpage and variation in dimensions, effectively prevent disconnection of wiring conductors, and reliably electrically connect electrodes such as semiconductor elements to an external electric circuit. An object of the present invention is to provide a method of manufacturing a wiring board that can be manufactured.

[0008]

A wiring board according to the present invention comprises 6
0 to 95% by weight of inorganic insulating powder and 5 to 40% by weight
Of the thermosetting resin, the inorganic insulating powder having a particle size of 0.05
The present invention is characterized in that a wiring conductor obtained by bonding a metal powder having a particle diameter of less than μm and a metal powder having a particle diameter of 0.05 μm or more with a thermosetting resin is adhered.

Further, the method for manufacturing a wiring board of the present invention comprises a step of preparing a precursor sheet formed by mixing a thermosetting resin precursor and an inorganic insulating powder, and the thermosetting resin is added to the precursor sheet. A step of printing a metal paste formed by mixing a precursor, a metal powder having a particle size of less than 0.05 μm and a metal powder having a particle size of 0.05 μm or more in a predetermined pattern, and the precursor sheet and the metal printed in the predetermined pattern And a step of thermally curing the paste.

[0010]

According to the wiring board of the present invention, since the insulating substrate is formed by bonding the inorganic insulating powder with the thermosetting resin having excellent toughness, the wiring boards are connected to each other or the wiring boards and the semiconductor device manufacturing automatic line. Even if it collides violently with a part of the above, the insulating substrate will not be chipped, cracked, or cracked.

According to the wiring board of the present invention, the wiring conductor has a metal powder having a particle size of less than 0.05 μm and a particle size of 0.05 μm.
It is formed by bonding the above metal powders with a thermosetting resin, and the metal powders with a particle size of less than 0.05 μm enter between the metal powders with a particle size of 0.05 μm or more, and the contact between the metal powders is made. As a result, the electrical resistance of the wiring conductor becomes low.

The wiring board of the present invention further comprises a precursor sheet obtained by mixing a curable resin precursor and an inorganic insulating powder, a thermosetting resin precursor, a metal powder having a particle diameter of less than 0.05 μm, and a particle diameter. It is manufactured by thermosetting a metal paste formed by mixing metal powder of 0.05 μm or more, and since there is no firing step, deformation and dimensional variation due to uneven firing shrinkage do not occur, and as a result, It is possible to reliably electrically connect the electrode of the semiconductor element or the like to the external electric circuit through the wiring conductor without causing a break in the wiring conductor.

[0013]

The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment in which the wiring board of the present invention is applied to a semiconductor element housing package for housing a semiconductor element, wherein 1 is an insulating substrate and 2 is a wiring conductor. The wiring substrate is formed by attaching the wiring conductor 2 to the insulating substrate 1.

The insulating substrate 1 comprises three insulating substrates 1a and 1a.
It is formed by stacking b and 1c, and has a recess 1d for accommodating a semiconductor element in the center of the upper surface thereof, and the semiconductor element 3 is provided on the bottom surface of the recess 1d via an adhesive such as resin. Adhesively fixed.

The three insulating substrates 1a, 1b and 1c constituting the insulating base 1 are made of an inorganic insulating powder such as silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate, epoxy resin or polyimide resin. It is formed by bonding with thermosetting resin of
Three insulating substrates 1a, 1b, 1c constituting the insulating base 1
Since each of them is formed by binding the inorganic insulating powder with a thermosetting resin having excellent toughness, even if an external force is applied to the insulating base 1, the insulating base 1 is applied by the external force.
There is no chipping, cracking, or cracking.

In addition, three insulating substrates 1 constituting an insulating substrate 1 formed by bonding the inorganic insulating powders with a thermosetting resin.
a, 1b, and 1c have an inorganic insulating powder content of 60% by weight.
When it is less than the above, the coefficient of thermal expansion of the insulating substrate 1 greatly differs from the coefficient of thermal expansion of the semiconductor element 3, the semiconductor element 3 emits heat during operation, and the heat is applied to both the semiconductor element 3 and the insulating substrate 1. Then, a large thermal stress is generated between them due to the difference in thermal expansion coefficient between the two, and the semiconductor element 3 is separated from the insulating substrate 1 due to the large thermal stress, or the semiconductor element 3 is cracked or chipped. I will end up. On the other hand, if it exceeds 95% by weight, the inorganic insulating powder cannot be completely bonded with the thermosetting resin, and the predetermined insulating substrates 1a, 1b, 1c cannot be obtained. Therefore, the insulating substrates 1a, 1b, 1c constituting the insulating base 1 are specified such that the amount of the inorganic insulating powder contained therein is in the range of 60 to 95% by weight.

A wiring conductor 2 is adhered and formed from the periphery of the recess 1d to the lower surface of the insulating substrate 1. The wiring conductor 2 is made of a metal powder of copper, silver, gold or the like and a thermosetting resin such as an epoxy resin. It is formed by a combination of.

The wiring conductor 2 functions to connect the electrode of the semiconductor element 3 to an external electric circuit, and the recess 1 of the insulating base 1 is formed.
d Each electrode of the semiconductor element 3 is electrically connected to the wiring conductor 2 located in the peripheral portion via the bonding wire 4, and the portion led out to the lower surface of the insulating substrate 1 is electrically connected to the external electric circuit. To be done.

The wiring conductor 2 is made of a metal powder bonded by a thermosetting resin such as an epoxy resin having a particle size of 0.05 μm.
and a metal powder having a particle size of 0.05 μm or more. The metal powder having a particle size of less than 0.05 μm is inserted between the metal powder having a particle size of 0.05 μm or more,
Wiring conductor 2 by promoting contact between each metal powder
The electrical resistance of is low.

The wiring conductor 2 composed of the metal powder having a particle size of less than 0.05 μm and the metal powder having a particle size of 0.05 μm or more has a particle size of 0. Less than 5% by weight of metal powder having a particle size of less than 05 μm and a particle size of 0.
If the metal powder having a particle size of 05 μm or more exceeds 95% by weight, the metal powder having a particle size of 0.05 μm or more does not sufficiently enter the metal powder having a particle size of 0.05 μm or more, and the electric resistance of the wiring conductor 2 tends to increase. When the metal powder having a particle size of less than 0.05 μm exceeds 40% by weight and the metal powder having a particle size of 0.05 μm or more is less than 60% by weight, the contact resistance between the metal powders increases and the electrical resistance of the wiring conductor 2 increases. Tends to be higher. Therefore, the wiring conductor 2 composed of the metal powder having a particle size of less than 0.05 μm and the metal powder having a particle size of 0.05 μm or more has a particle size of 0.
The metal powder of less than 05 μm is in the range of 5 to 40% by weight,
60 to 95% by weight of metal powder with a particle size of 0.05 μm or more
It is preferable to set it as the range of.

The wiring conductor 2 is formed by depositing a metal having excellent corrosion resistance such as nickel and gold on the exposed surface by a plating method to a thickness of 1 to 20 μm. Oxidation and corrosion can be effectively prevented, and the bonding wire 4 can be firmly electrically connected to the wiring conductor 2. Therefore, the wiring conductor 2
It is preferable that a metal having excellent corrosion resistance, such as nickel or gold, and having good conductivity is deposited on the exposed surface by a plating method to a thickness of 1 to 20 μm.

Thus, according to the above wiring board, the semiconductor element 3 is adhered and fixed to the bottom surface of the recess 1d of the insulating substrate 1 with an adhesive such as resin, and each electrode of the semiconductor element 3 is wired with the bonding wire 4. After electrically connecting to the conductor 2, the lid 5 is joined to the upper surface of the insulating base 1 via a sealing material made of resin or the like, and the semiconductor element is placed inside the container made up of the insulating base 1 and the lid 5. A semiconductor device as a product is completed by hermetically containing 3 therein.

Next, a method of manufacturing the wiring board used for the semiconductor element housing package will be described.

First, as shown in FIG. 2A, three precursor sheets 11a, 11b and 11c are prepared. The three precursor sheets 11a, 11b, and 11c are formed by bonding inorganic insulating powders with a thermosetting resin precursor. For example, silicon oxide powders having a particle size of 0.1 to 100 μm are mixed with bisphenol. A type epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin and other epoxy resins and amine type curing agents, imidazole type curing agents, acid anhydride type curing agents and other curing agents are added and mixed to form a paste, Then, the paste is formed into a sheet and is heated at a temperature of about 25 to 100 ° C. for 1 to 60 minutes to be semi-cured.

Next, as shown in FIG. 2B, the recess 1 for accommodating the semiconductor element 3 in the two precursor sheets 11a, 11b among the three precursor sheets 11a, 11b, 11c.
The openings A and A ′ to be the d are formed by the two precursor sheets 11b,
Through holes B and B'for routing the wiring conductor 2 are formed in 11c.

The openings A, A'and the through holes B, B'are formed by subjecting the precursor sheets 11a, 11b, 11c to a well-known punching process to obtain the precursor sheets 11a, 11b, 11 '.
It is formed by drilling a hole of a predetermined shape in each of c.

Next, as shown in FIG. 2 (c), a metal paste 12 to be the wiring conductor 2 is formed on the upper and lower surfaces of the precursor sheets 11b and 11c and in the through holes B and B'by a conventionally known screen printing method. It is manufactured by applying a predetermined pattern by printing and heating it at a temperature of about 25 to 100 ° C. for 1 to 60 minutes to semi-cure it.

The metal paste 12 is, for example, a metal powder having a particle size of 0.01 μm, 1 μm, 5 μm, 10 μm.
m mixed copper powder, bisphenol A type epoxy resin,
An epoxy resin such as a novolac type epoxy resin or a glycidyl ester type epoxy resin and a curing agent such as an amine type curing agent, an imidazole type curing agent or an acid anhydride type curing agent are added and mixed to form a paste.

Finally, the above three precursor sheets 11
a, 11b, 11c are stacked on top of each other and heated at a temperature of about 80 to 300 ° C. for about 10 seconds to 24 hours to form a predetermined pattern on the precursor sheets 11a, 11b, 11c and the precursor sheets 11b, 11c. By completely thermosetting the metal paste 12 printed and applied to
A wiring board used in a package for housing a semiconductor device, in which the wiring conductor 2 is adhered to the insulating substrate 1 as shown in (3), is completed. In this case, the precursor sheets 11a, 11b, 11
c and the metal paste 12 hardly shrink during thermosetting, so that the obtained wiring board is never deformed or the dimensions are not varied, and the wiring conductor is not broken. Through this, the electrodes of the semiconductor element or the like can be reliably electrically connected to the external electric circuit.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-mentioned embodiments, the wiring board of the present invention is applicable. Although the description has been given by taking as an example the case where the above is applied to a semiconductor element housing package for housing a semiconductor element, this may be applied to a hybrid integrated circuit board or the like.

In the above-mentioned embodiment, the wiring board is manufactured by laminating the three precursor sheets. However, the wiring board is manufactured by using one, two, or four or more precursor sheets. May be.

[0032]

According to the wiring board of the present invention, since the insulating substrate is formed by bonding the inorganic insulating powder with the thermosetting resin having excellent toughness, the wiring boards are manufactured together or the wiring board and the semiconductor device are manufactured. Even if a part of the automatic line collides violently, the insulating substrate will not be chipped, cracked, or cracked.

According to the wiring board of the present invention, the wiring conductor has a metal powder having a particle size of less than 0.05 μm and a particle size of 0.05 μm.
It is formed by bonding the above metal powders with a thermosetting resin, and the metal powders with a particle size of less than 0.05 μm enter between the metal powders with a particle size of 0.05 μm or more, and the contact between the metal powders is made. As a result, the electrical resistance of the wiring conductor becomes low.

The wiring board of the present invention further comprises a precursor sheet obtained by mixing a curable resin precursor and an inorganic insulating powder, a thermosetting resin precursor, a metal powder having a particle diameter of less than 0.05 μm, and a particle diameter. It is manufactured by thermosetting a metal paste formed by mixing metal powder of 0.05 μm or more, and since there is no firing step, deformation and dimensional variation due to uneven firing shrinkage do not occur, and as a result, It is possible to reliably electrically connect the electrode of the semiconductor element or the like to the external electric circuit through the wiring conductor without causing a break in the wiring conductor.

[Brief description of drawings]

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

2A to 2C are cross-sectional views for each step for explaining the method for manufacturing a wiring board according to the present invention.

[Explanation of symbols]

 Insulation bases 1a, 1b, 1c ... Insulation substrate 2 ... Wiring conductors 11a, 11b, 11c・ ・ ・ Precursor sheet 12 ・ ・ ・ ・ ・ ・ ・ ・ ・ Metal paste

Claims (2)

[Claims] 1. An inorganic insulating powder of 60 to 95% by weight and 5
To 40% by weight of a thermosetting resin, the inorganic insulating powder is bonded by the thermosetting resin to an insulating substrate, and a metal powder having a particle diameter of less than 0.05 μm and a particle diameter of 0.05
A wiring board formed by depositing a wiring conductor in which metal powder having a size of μm or more is bonded by a thermosetting resin resin. 2. A step of preparing a precursor sheet obtained by mixing a thermosetting resin precursor and an inorganic insulating powder, and the thermosetting resin precursor and a particle size of less than 0.05 μm in the precursor sheet. Of the metal powder and the metal powder having a particle size of 0.05 μm or more are printed in a predetermined pattern, and the precursor sheet and the metal paste printed in the predetermined pattern are thermally cured. Wiring board manufacturing method.