JPH0992947A - Wiring board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of chipping, breaking, cracking, etc., in an insulating base body by providing wiring conductors, consisting of a metal member and a resin and formed by joining them each other with a low melting point metal whose melting point being not higher than a predetermined temperature or by fusing and joining them each other, on the insulating base body formed by combining inorganic insulator powder and thermosetting resin with their respective weight percentages being in particular ranges. SOLUTION: Each of insulating base bodies 1a, 1b, 1c constituting an insulating base body 1 contains internally inorganic insulator powder in a particular range of 60 to 95weight%. Further, a wiring conductor 2 is provided on the insulating base body 1 at the periphery of its recess 1d and at its lower surface, and the wiring conductor 2 is constructed from a metal member and an electrically conductive and thermosetting resin, the metal member being formed from metal powder consisting of copper joined together with a low melting point metal consisting of tin whose melting point being not higher than 300 deg.C or formed from a low melting point metal powder consisting of eutectic solder of lead-tin whose melting point being not higher than 300 deg.C by dissolving and joining them together. Thus, even if violent collision occurs between the wiring board and a part of the automatic semiconductor production line, occurrence of a break, etc., in the insulating base body 1 can be prevented.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Hitherto, as a wiring board used for a wiring board, for example, a semiconductor element housing package for housing a semiconductor element housing package, 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, has an insulating base body having a recessed portion for accommodating a semiconductor element in the center of its upper surface, and tungsten, molybdenum, etc. led out from the periphery of the recessed portion of the insulating base material 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, and the like are bonded together, and the semiconductor element is hermetically housed in the concave portion of the insulating substrate. 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, a solvent, etc. to a ceramic raw material powder such as calcium oxide 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, the semiconductor device has a drawback that it cannot operate 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]

A wiring board according to the present invention comprises 60
% To 95% by weight of inorganic insulating powder and 5% to 40% by weight of thermosetting resin, and at least one insulating substrate in which the inorganic insulating powder is bonded by the thermosetting resin. The melting point of the metal powder is 30 on the insulating substrate.
Bonded with a low melting point metal of 0 ° C or less, or with a melting point of 3
It is characterized in that a wiring conductor made of a metal member formed by melting and bonding low-melting-point metal powders of 00 ° C. or less to each other and a conductive and thermosetting resin is applied. .

Further, the method of 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 a conductive thermosetting resin for the precursor sheet. A step of printing a metal precursor formed by mixing a resin precursor, a low melting point metal powder having a melting point of 300 ° C. or lower and a metal powder or a low melting point metal powder having a melting point of 300 ° C. or lower in a predetermined pattern, and the precursor sheet And heating the thermosetting resin precursor of the metal paste to bond the metal powder in the metal paste with the low-melting metal powder having a melting point of 300 ° C. or lower, or the low-melting metal powder having a melting point of 300 ° C. or lower to each other. A step of thermally curing the thermosetting resin precursor of the precursor sheet and the conductive thermosetting resin precursor of the metal paste while bonding.

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 mutually connected or the wiring board 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 is formed by joining metal powders with a low melting point metal having a melting point of 300 ° C. or lower, or by melting low melting point metal powders having a melting point of 300 ° C. or lower with each other. Since it is formed of the metal member formed by the above and the resin which is conductive and thermosetting, the electric connection between the metal powders or the low melting point metal powders having a melting point of 300 ° C. or less is ensured, and as a result, The electric resistance of the wiring conductor can be made low, and at the same time, the exposed surface of the wiring conductor can be satisfactorily coated with the plated metal layer, and the surface of the wiring conductor can be completely covered with the plated metal layer.

Further, the 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 a conductive thermosetting resin precursor on the precursor sheet. A step of printing a metal paste having a melting point of 300 ° C. or lower and a metal powder or a low melting point metal powder having a melting point of 300 ° C. or lower in a predetermined pattern, the precursor sheet and the metal paste. When the thermosetting resin precursor is heated, the melting point of the metal powder in the metal paste is 3
Conductive thermosetting of the thermosetting resin precursor of the precursor sheet and the metal paste while bonding with low melting point metal powder of 00 ° C. or lower or bonding of low melting point metal powder of 300 ° C. or lower with each other Since the wiring board is manufactured by the step of thermally curing the resin precursor, deformation and dimensional variation due to uneven shrinkage due to firing do not occur.

[0011]

DETAILED DESCRIPTION OF THE INVENTION 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 laminating 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 of the recess 1d via an adhesive such as resin. Adhesively fixed.

The three insulating substrates 1a, 1b, 1c constituting the insulating base 1 are, for example, silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate,
It is formed by bonding inorganic insulating material powders such as strontium titanate and titanium oxide with a thermosetting resin such as epoxy resin, polyimide resin, polyphenylene ether resin, etc.
Since each of a, 1b, and 1c is formed by binding an 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 chipped by the external force. No cracks, cracks, etc. will occur.

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 each have a content of the inorganic insulating powder 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. Resulting in. 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, and 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 formed on the insulating substrate 1 from the periphery of the recess 1d to the lower surface thereof. The wiring conductor 2 is made of a metal powder made of copper and a low melting point metal made of tin having a melting point of 300 ° C. or less. And conductive with a metal member formed by joining or melting low melting point metal powders of lead-tin eutectic solder with melting points of 300 ° C. or less to each other,
It is also composed of a thermosetting resin.

The wiring conductor 2 serves to connect the electrode of the semiconductor element 3 to an external electric circuit, and the recess 1 of the insulating substrate 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 also contains metal powder having a melting point of 3
Bonded with a low melting point metal of 00 ° C or less, or with a melting point of 3
Since it is composed of a metal member formed by melting and joining low-melting-point metal powders of 00 ° C. or less to each other and a resin that is conductive and thermosetting, the metal powders have melting points or melting points of 3 or less.
The electrical connection between the low-melting-point metal powders of 00 ° C. or less is ensured, and as a result, the electrical resistance of the wiring conductor 2 can be reduced.

Further, the wiring conductor 2 is made of metal powder and has a melting point of 3
Bonded with a low melting point metal of 00 ° C or less, or with a melting point of 3
Since it is composed of a metal member formed by melting and joining low-melting-point metal powders of 00 ° C. or less to each other and a resin that is conductive and thermosetting, the exposed surface has good conductivity and wax. A material such as nickel or gold having good wettability can be layered by electroplating to a predetermined thickness, thereby strengthening the bonding between the wiring conductor 2 and the bonding wire 4 and connecting each electrode of the semiconductor element 3 to each other. The wiring conductor 2 can be reliably and firmly electrically connected via the bonding wire 4.

When the total amount of the metal powder contained in the wiring board 2 and the low melting point metal powder having a melting point of 300 ° C. or less is less than 70% by weight based on the total weight of the wiring conductor 2, the low melting point metal is formed. It becomes difficult to join the metal powders with each other or to join the low melting point metal powders well, and the electric resistance of the wiring conductor 2 becomes high, and when it exceeds 95% by weight, the wiring conductor 2 is firmly bonded to the insulating substrate 1. It tends to be difficult to apply to. Therefore, the total amount of the metal powder contained in the wiring conductor 2 and the low melting point metal powder having a melting point of 300 ° C. or less is 70% by weight to 95% with respect to the total weight of the wiring conductor 2.
It is preferable to set it in the range of weight%.

When the average particle diameter of the metal powder or the low melting point metal powder having a melting point of 300 ° C. or less contained in the wiring conductor 2 is less than 0.1 μm, the metal powder and the low melting point metal powder are aggregated and uniform. When the dispersion is not obtained and the width exceeds 50 μm, the width of the wiring conductor 2 is generally required to be 50 μm.
It tends to be difficult to set the thickness to the range of 200 to 200 μm. Therefore, it is preferable that the metal powder contained in the wiring conductor 2 and the low melting point metal powder having a melting point of 300 ° C. or less have an average particle size in the range of 0.1 μm to 50 μm.

In addition, the conductive material that constitutes the wiring conductor 2,
The thermosetting resin is obtained by blending a thermosetting resin such as an epoxy resin, a phenol resin, or a polyimide resin with a conductive resin such as a polyacetylene-based resin or a polyphenylene resin.

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 with reference to FIG.

First, as shown in FIG. 2A, three precursor sheets 11a, 11b and 11c are prepared.

The three precursor sheets 11a, 11b,
11c is formed by bonding inorganic insulating powder with a thermosetting resin precursor, and has a particle size of 0.1 to 0.1, for example.
Epoxy resin such as bisphenol A type epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin, etc. and amine type curing agent, imidazole type curing agent, acid anhydride type curing agent, etc. are added to 100 μm silicon oxide powder. It is manufactured by mixing to form a paste, and then forming the paste into a sheet and heating at a temperature of about 25 to 100 ° C. for 1 to 60 minutes to semi-cure.

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 '.
c is formed by piercing 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.

As the metal paste 12, for example, a copper powder having a particle size of about 0.1 μm to 20 μm as a metal powder, and a low melting point metal powder made of tin having a particle size of about 0.1 μm to 20 μm is used as the copper powder. And a low melting point metal powder mixed in a weight ratio of 95: 5 to 5:95, or a low melting point metal powder composed of lead-tin eutectic solder having a particle size of about 1 μm to 50 μm, and bisphenol. A type epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin, or other epoxy resin is mixed with conductive polyacetylene type resin or polyphenylene resin, and an amine type curing agent, imidazole type curing agent, acid anhydride type curing agent A paste is prepared by mixing a conductive thermosetting resin precursor containing a curing agent such as a curing agent.

Finally, the three precursor sheets 11
While stacking a, 11b, and 11c on top of each other and heating them at a temperature of about 300 ° C. for about 10 seconds to 24 hours, while bonding the copper powder in the metal paste with the low melting point metal powder,
Alternatively, the thermosetting resin precursors of the precursor sheets 11a, 11b, 11c and the metal paste 12 printed and applied in a predetermined pattern on the precursor sheets 11b, 11c while bonding low melting point metal powders made of tin to each other. By completely thermosetting the conductive thermosetting resin precursor of (1), the wiring substrate used for the package for housing the semiconductor element in which the wiring conductor 2 is adhered to the insulating substrate 1 as shown in FIG. 1 is completed. .
In this case, the precursor sheets 11a, 11b, 11c and the metal paste 12 are hardly contracted at the time of thermosetting, so that the obtained wiring board is not deformed or the dimension is not varied, and the wiring conductor 2 is not broken. It is possible to reliably electrically connect the electrodes of the semiconductor element 3 and the like to the external electric circuit through the wiring conductor 2 without causing any trouble.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiments, the wiring board of the present invention is used. In the above description, the case where the above is applied to a semiconductor element housing package that houses a semiconductor element has been described as an example, but this may be applied to a hybrid integrated circuit board.

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.

[0033]

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 clicked.

Further, according to the wiring board of the present invention, the wiring conductor is formed by joining metal powders with a low melting point metal having a melting point of 300 ° C. or lower, or by melting and joining low melting point metal powders having a melting point of 300 ° C. or lower with each other. Since it is formed of the metal member formed by the above and the resin which is conductive and thermosetting, the electric connection between the metal powders or the low melting point metal powders having a melting point of 300 ° C. or less is ensured, and as a result, The electric resistance of the wiring conductor can be made low, and at the same time, the exposed surface of the wiring conductor can be satisfactorily coated with the plated metal layer, and the surface of the wiring conductor can be completely covered with the plated metal layer.

Further, the 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 a conductive thermosetting resin precursor on the precursor sheet. A step of printing a metal paste having a melting point of 300 ° C. or lower and a metal powder or a low melting point metal powder having a melting point of 300 ° C. or lower in a predetermined pattern, the precursor sheet and the metal paste. When the thermosetting resin precursor is heated, the melting point of the metal powder in the metal paste is 3
Conductive thermosetting of the thermosetting resin precursor of the precursor sheet and the metal paste while bonding with low melting point metal powder of 00 ° C. or lower or bonding of low melting point metal powder of 300 ° C. or lower with each other Since the wiring board is manufactured by the step of thermally curing the resin precursor, deformation and dimensional variation due to uneven shrinkage due to firing do not occur.

[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. At least 1 comprising 60% by weight to 95% by weight of an inorganic insulating powder and 5% by weight to 40% by weight of a thermosetting resin, said inorganic insulating powder being bound by said thermosetting resin. A metal member formed by bonding metal powder with a low-melting point metal having a melting point of 300 ° C. or lower, or by melting and bonding low-melting point metal powder having a melting point of 300 ° C. or lower to an insulating substrate composed of a single insulating substrate. A wiring board on which a wiring conductor made of a resin that is electrically conductive and thermosetting is adhered. 2. A step of preparing a precursor sheet formed by mixing a thermosetting resin precursor and an inorganic insulating powder, a conductive thermosetting resin precursor in the precursor sheet, and a melting point of 300.
Low melting point metal powder below ℃ and metal powder or melting point 300
A step of printing a metal paste formed by mixing a low melting point metal powder of ℃ or less with a predetermined pattern, heating the precursor sheet and the thermosetting resin precursor of the metal paste, and melting the metal powder in the metal paste Of the thermosetting resin precursor of the precursor sheet and the conductive thermosetting of the metal paste while bonding with a low melting point metal powder having a melting point of 300 ° C. or lower or bonding the low melting point metal powders having a melting point of 300 ° C. or lower with each other. And a step of thermally curing the resinous resin precursor.