JP3145621B2 - Wiring board and manufacturing method thereof - Google Patents

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 Conventionally, a multilayer ceramic wiring board capable of relatively high-density wiring has been widely used as a wiring board used for a wiring board, for example, a semiconductor element housing package for housing a semiconductor element housing package. This wiring board is made of ceramics such as an aluminum oxide sintered body, and has an insulating base having a concave portion for accommodating a semiconductor element in a central portion of an upper surface thereof, and tungsten, molybdenum, etc. led out from the periphery of the concave portion to the lower surface of the insulating base. And a semiconductor element is bonded and fixed to the bottom surface of the concave portion of the insulating base via an adhesive such as glass, resin, or brazing material, and each electrode of the semiconductor element is For example, glass is electrically connected to a wiring conductor via an electrical connection means such as a bonding wire, and thereafter, a cover made of metal, ceramics, or the like is placed on the upper surface of the insulating base so as to cover the concave portion of the insulating base. , A resin, a brazing material, or the like, and a semiconductor device as a product by being hermetically housed in a concave portion of the insulating base. To become.

The conventional wiring board is generally manufactured by a ceramic green sheet laminating method. Specifically, aluminum wiring, 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 by mixing and forming this into a sheet using a conventionally known doctor blade method, Thereafter, the ceramic green sheet is subjected to a suitable punching process and a metal paste to be a wiring conductor is applied by printing in a predetermined pattern, and finally, the ceramic green sheets are stacked up and down in a predetermined order to form a ceramic forming body. It is manufactured by firing the ceramic forming 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 constituting the insulating base have a hard and brittle property, the automatic wiring of the transfer process and the semiconductor device manufacturing is difficult. When the wiring boards collide with each other or the wiring board and a part of the semiconductor device manufacturing automatic line violently collide with each other, chips, cracks, cracks, etc. occur in the insulating base, and as a result, the semiconductor element can be housed in an airtight manner. However, the semiconductor device cannot operate normally and stably for a long period of time.

Further, according to the method of manufacturing a wiring substrate, when firing the ceramic formed body, uneven firing shrinkage occurs in the ceramic formed body due to the variation in the density of the ceramic raw material powder in each ceramic green sheet. In addition, the resulting wiring board has a defect such as deformation such as warpage or dimensional variation, and a large deformation or dimensional variation leads to disconnection of the wiring conductor.

[0006]

According to the present invention, there is provided a wiring board comprising:
A precursor sheet comprising inorganic insulating powder in an amount of 5% to 95% by weight and a thermosetting resin in an amount of 5% to 40% by weight, wherein the inorganic insulating powder is bonded with a precursor of the thermosetting resin; Is semi-cured, a plurality of the substrates are laminated and thermally cured, and the insulating substrate of the insulating substrate formed by laminating a plurality of insulating substrates in which the inorganic insulating powder is bonded by the thermosetting resin has metal. It is characterized in that a wiring conductor in which powder is joined with a low melting point metal having a melting point of 300 ° C. or less is applied with a thermosetting resin.

Further, according to the method for producing a wiring board of the present invention, there is provided a step of preparing a precursor sheet formed by mixing a thermosetting resin precursor and an inorganic insulating powder; Printing a metal paste formed by mixing a body, metal powder, and a low-melting metal powder having a melting point of 300 ° C. or less in a predetermined pattern, and heating the metal paste printed and applied on the predetermined pattern by induction heating, And a step of thermosetting the thermosetting resin precursor of the precursor sheet and the metal paste.

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

Further, according to the wiring board of the present invention, since the metal powder of the wiring conductor is joined with a low melting point metal having a melting point of 300 ° C. or less, electrical connection between the metal powders is ensured, and the electric resistance of the wiring conductor is reduced. Low resistance can be achieved.

The wiring board of the present invention further comprises a step of preparing a precursor sheet comprising a mixture of a thermosetting resin precursor and an inorganic insulating powder; And a low melting point metal powder having a melting point of 300 ° C. or lower. A step of printing the metal paste in a predetermined pattern, and heating the metal paste printed and applied on the predetermined pattern by induction heating to reduce the metal powder to a low melting point metal. And a step of thermally curing the thermosetting resin precursor of the precursor sheet and the metal paste, thereby producing a wiring board, so that deformation and dimensional variation due to uneven shrinkage due to firing occur. Never.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will 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 base, and 2 is a wiring conductor.
The wiring substrate formed by attaching the wiring conductor 2 to the insulating base 1 is a wiring substrate.

The insulating base 1 comprises three insulating substrates 1a, 1
The semiconductor element 3 is formed by laminating b and 1c, and has a concave portion 1d for accommodating a semiconductor element in the center of the upper surface thereof. Adhesively fixed.

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

Incidentally, three insulating substrates 1 constituting an insulating base 1 formed by bonding the inorganic insulating powder with a thermosetting resin.
a, 1b, and 1c each have a content of the inorganic insulating powder of 60% by weight.
If it is less than 1, the coefficient of thermal expansion of the insulating substrate 1 greatly differs from the coefficient of thermal expansion of the semiconductor element 3, and the semiconductor element 3 generates heat during operation, and the heat is applied to both the semiconductor element 3 and the insulating substrate 1. As a result, a large thermal stress is generated between the two due to the difference in the coefficient of thermal expansion between the two, and the large thermal stress causes the semiconductor element 3 to be separated from the insulating base 1 and the semiconductor element 3 to be 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 amount of the inorganic insulating powder contained in each of the insulating substrates 1a, 1b, and 1c constituting the insulating base 1 is specified in the range of 60 to 95% by weight.

The insulating base 1 is provided with a wiring conductor 2 attached from the periphery of the concave portion 1d to the lower surface. The wiring conductor 2 is made of a metal powder such as copper, silver, or gold having a low melting point of 300 ° C. or less. It is formed by attaching a metal, specifically, a material joined via solder, to the insulating base 1 via a thermosetting resin.

The wiring conductor 2 serves to connect the electrodes of the semiconductor element 3 to an external electric circuit, and
d Each electrode of the semiconductor element 3 is electrically connected to the wiring conductor 2 located at the peripheral portion via a bonding wire 4, and the portion led out to the lower surface of the insulating base 1 is electrically connected to an external electric circuit. Is done.

The wiring conductor 2 is formed by joining a metal powder such as copper, silver, and gold with a low-melting metal such as a solder having a melting point of 300 ° C. or less, so that electrical connection between the metal powders is ensured. As a result, the electric resistance of the wiring conductor 2 can be made low.

The wiring conductor 2 composed of the metal powder, the low melting point metal having a melting point of 300 ° C. or less and the thermosetting resin is the total weight of the metal powder and the low melting point metal having a melting point of 300 ° C. or less. When it is less than 70% by weight based on the total weight, copper,
Bonding of a metal powder such as silver or gold to a low melting point metal such as solder at 300 ° C. or less becomes incomplete, and if it exceeds 95% by weight, the wiring conductor 2 is firmly adhered to the insulating base 1 with a thermosetting resin. It is difficult to make the wiring conductor 2 brittle and the wiring conductor 2 tends to be weak. Therefore, the total weight of the metal powder contained in the wiring conductor 2 and the low melting point metal having a melting point of 300 ° C. or less is preferably in the range of 70% by weight to 95% by weight based on the total weight of the wiring conductor 2.

The metal powder contained in the wiring conductor 2 and the low melting point metal having a melting point of 300 ° C. or less are used when the amount of the metal powder is less than 20% by weight based on the total weight of the metal powder and the low melting point metal. On the other hand, the amount of the low-melting-point metal increases, and the low-melting-point metals fuse with each other, making it difficult to integrate the metal powder into the metal powder and increasing the electric resistance of the wiring conductor 2. If it exceeds, the amount of the low melting point metal to be joined with the metal powder becomes relatively small, so that the metal powder cannot be completely joined and the electric resistance value of the wiring conductor 2 tends to increase. Therefore, the wiring conductor 2
Is preferably in the range of 20% by weight to 80% by weight based on the total weight of the metal powder and the low melting point metal.

When the average particle diameter of the metal powder contained in the wiring conductor 2 and the low melting point metal having a melting point of 300 ° C. or less is less than 0.1 μm, the metal powder and the low melting point metal are aggregated and uniformly dispersed. When the width exceeds 50 μm, the width of the wiring conductor 2 is generally required to be 50 μm to 2 μm.
It becomes difficult to print and form in the range of 00 μm. Accordingly, the metal powder contained in the wiring conductor 2 has a melting point of 30%.
It is preferable that the low melting point metal having a temperature of 0 ° C. or lower has an average particle size in a range of 0.1 μm to 50 μm.

Thus, according to the above-mentioned wiring board, the semiconductor element 3 is bonded and fixed to the bottom surface of the concave portion 1d of the insulating base 1 with an adhesive such as a resin, and each electrode of the semiconductor element 3 is wired via the bonding wire 4. After being electrically connected to the conductor 2, the lid 5 is bonded 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 formed of the insulating base 1 and the lid 5. The semiconductor device as a product is completed by housing 3 in an airtight manner.

Next, a method of manufacturing a wiring board used in the package for housing a semiconductor element 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 an inorganic insulating powder with a thermosetting resin precursor, for example, having a particle size of 0.1 to
Epoxy resin such as bisphenol A type epoxy resin, novolak type epoxy resin, glycidyl ester type epoxy resin, etc. and curing agent such as amine type curing agent, imidazole type curing agent, acid anhydride type curing agent are added to 100 μm silicon oxide powder. The paste is mixed to form a paste. Thereafter, the paste is formed into a sheet and heated at a temperature of about 25 to 100 ° C. for 1 to 60 minutes to be semi-cured.

Next, as shown in FIG. 2 (b), two of the three precursor sheets 11a, 11b, 11c have the recess 1 for accommodating the semiconductor element 3 in the two precursor sheets 11a, 11b.
The openings A and A ′ serving as d are formed by two precursor sheets 11b,
11c, through holes B and B 'for routing the wiring conductor 2 are respectively formed.

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

Next, as shown in FIG. 2C, 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. The metal paste 12 printed and applied in a predetermined pattern is then heated by induction heating to bond the metal powder with a low melting point metal and heated at a temperature of about 25 to 100 ° C. for 1 to 60 minutes. It is manufactured by semi-curing a thermosetting resin.

As the metal paste 12, for example, copper powder having a particle size of about 0.1 μm to 20 μm as a metal powder, solder having a particle size of about 1 μm to 50 μm, bisphenol A type epoxy resin, novolak type epoxy resin, An epoxy resin such as a glycidyl ester type epoxy resin and a curing agent such as an amine curing agent, an imidazole curing agent, and an acid anhydride curing agent are added and mixed to form a paste.

The heating by induction heating of the metal paste 12 printed and applied in a predetermined pattern on the upper and lower surfaces of the precursor sheets 11b and 11c and in the through holes B and B 'is performed, for example, by printing the metal paste 12 in a predetermined pattern. The obtained precursor sheets 11b and 11c are arranged in a heating coil portion of a high-frequency brazing device, and a predetermined high-frequency power necessary for causing the low-melting-point metal in the metal paste to generate heat by electromagnetic induction is applied to the heating coil. This is done by:

Finally, the three precursor sheets 11
a, 11b, and 11c are vertically stacked 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, and 11c and the precursor sheets 11b and 11c. By completely thermosetting the metal paste 12 printed and applied to
A wiring board used for a semiconductor element storage package in which a wiring conductor 2 is attached to an insulating base 1 as shown in FIG. In this case, the precursor sheets 11a, 11b, 11
c and the metal paste 12 hardly shrink at the time of thermosetting, so that there is no deformation or variation in dimensions of the obtained wiring board, no breakage in the wiring conductors, and no semiconductor via the wiring conductors. Electrodes such as elements can be reliably electrically connected to an external electric circuit.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. Has been described as an example in which the present invention is applied to a semiconductor element housing package for housing a semiconductor element, but this may be applied to a hybrid integrated circuit board.

In the above embodiment, a wiring board is manufactured by laminating three precursor sheets. However, a wiring board is manufactured by using one, two, or four or more precursor sheets. You may.

[0033]

According to the wiring board of the present invention, since the insulating base is formed by bonding the inorganic insulating powder with a thermosetting resin having excellent toughness, the wiring boards are mutually connected 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.

Further, according to the wiring board of the present invention, since the metal powder of the wiring conductor is joined with a low melting point metal having a melting point of 300 ° C. or less, the electrical connection between the metal powders is ensured, and the electric resistance of the wiring conductor is reduced. Low resistance can be achieved.

Further, the wiring board of the present invention comprises a step of preparing a precursor sheet comprising a mixture of a thermosetting resin precursor and an inorganic insulating powder; And a low melting point metal powder having a melting point of 300 ° C. or lower. A step of printing the metal paste in a predetermined pattern, and heating the metal paste printed and applied on the predetermined pattern by induction heating to reduce the metal powder to a low melting point metal. And a step of thermally curing the thermosetting resin precursor of the precursor sheet and the metal paste, thereby producing a wiring board, so that deformation and dimensional variation due to uneven shrinkage due to firing occur. Never.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 ... Insulating base 1a, 1b, 1c Insulating substrate 2 Wiring conductors 11a, 11b, 11c ... Precursor sheet 12 ... Metal paste

Claims (2)

(57) [Claims] 1. An inorganic insulating powder 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 a precursor of the thermosetting resin.
Semi-cured precursor sheets are combined and multiple
Laminated to thermally cured, the insulating substrate of the inorganic insulator powder by stacking a plurality of insulating substrates joined by the thermosetting resin formed <br/> Ru insulating substrate, melting point metal powder 300
A wiring board formed by applying a wiring conductor bonded with a low melting point metal at a temperature of not more than ° C with a thermosetting resin. 2. A step of preparing a precursor sheet comprising a mixture of a thermosetting resin precursor and an inorganic insulating powder; and providing the precursor sheet with a thermosetting resin precursor, a metal powder and a melting point of 30%.
The 0 ℃ following metal paste formed by mixing a low-melting-point metal powder comprising the steps of: printing a predetermined pattern is heated by induction heating the printed coated metallic paste to the predetermined pattern,
A method for manufacturing a wiring board, comprising: a step of bonding metal powder with a low melting metal; and a step of thermally curing a thermosetting resin precursor of a precursor precursor sheet and a metal paste.