JPH10150248A - Wiring board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strengthen the bonding strength of wiring conductors to an insulating base body by a method wherein an intermediate layer consisting of a thermosetting resin is made to interpose between the insulating base body and the wiring conductors and at the same time, the thermosetting resin of the intermediate layer is bonded to the thermosetting resin of each of the insulating base body and the wiring conductors by a crosslinking reaction. SOLUTION: An intermediate layer is made to interpose between wiring conductors 2 and the upper surface of an insulating substrate 1b constituting an insulating base body 1. The thermosetting resin of the intermediate layer causes a crosslinking reaction with the thermosetting resin of each of the substrate 1b and the wiring conductors 2, whereby the wiring conductors 2 are firmly bonded to the substrate 1b. Thereby, when electrodes on a semiconductor element 3 are connected with the conductors 2 via bonding wires 4 or at other times, the conductors 2 are never separated from the base body 1 (the surface of the substrate 1b) by an external force even if the large external force is applied to the conductors 2. Thereby, it becomes possible to connect electrically each electrode on the element 3 with each wiring conductor 2 reliably and firmly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board,
More specifically, the present invention relates to a semiconductor element housing package for housing a semiconductor element, and a wiring board used for a hybrid integrated circuit device or 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 made of ceramics such as an aluminum oxide sintered body, and a semiconductor element is housed in a central portion of an upper surface thereof. And a wiring conductor made of a refractory metal powder such as tungsten or molybdenum which is led out from the periphery of the concave portion to the lower surface of the insulating substrate, and a semiconductor element is formed on the bottom surface of the concave portion of the insulating substrate. Glass, resin, and adhesively fixed via an adhesive such as a brazing material, and each electrode of the semiconductor element is electrically connected to a wiring conductor through an electrical connection means such as a bonding wire. A sealing member made of glass, resin, brazing material, or the like, with a cover made of metal, ceramics, or the like on the upper surface of the insulating base so as to cover the concave portion of the insulating base. Through by joining a semiconductor device as a product by housing airtightly semiconductor element in the recess of the insulating substrate.

Incidentally, this conventional wiring board is generally manufactured by a ceramic green sheet laminating method.
Specifically, an appropriate organic binder, a solvent, etc. are added to a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide to form a slurry, which is formed by a conventionally known doctor blade method.
A plurality of ceramic green sheets are obtained by forming the sheet into a sheet shape. Thereafter, the ceramic green sheet is subjected to an appropriate punching process, and a metal paste serving as a wiring conductor is printed and applied in a predetermined pattern. Are laminated one above the other in a predetermined order to form a green ceramic molded body, and the green ceramic molded body is fired at a high temperature of about 1600 ° C. in a reducing atmosphere.

However, in the conventional wiring board, since ceramics such as an aluminum oxide sintered body constituting the insulating base have a hard and brittle property, the wiring boards are not connected to each other in a transfer process or an automatic line for manufacturing semiconductor devices. If the wiring board and a part of the automatic semiconductor device manufacturing line collide violently, the insulating substrate may be chipped, cracked, cracked, etc., and as a result, the semiconductor element cannot be housed in an airtight manner, and the semiconductor element may not be long. There was a drawback that normal and stable operation could not be achieved over a period of time.

According to the method of manufacturing a wiring board,
When firing the green ceramic molded body, uneven firing shrinkage occurs in the green ceramic molded body, and deformation and dimensional variation such as warpage occur in the obtained wiring board, so that each electrode of the semiconductor element is connected to a predetermined wiring conductor. Alternatively, the wiring conductor cannot be accurately and reliably electrically connected to a predetermined external electric circuit.

Therefore, the insulating base of the wiring board is replaced with conventional ceramics and the inorganic insulating powder is bonded with a thermosetting resin, and the wiring conductor is replaced with the conventional high melting point metal powder and the metal powder is replaced with the thermosetting resin. There has been proposed a wiring board joined by a resin. A wiring board composed of an insulating base formed by bonding the inorganic insulating powder with a thermosetting resin and a wiring conductor formed by bonding a metal powder with a thermosetting resin, comprises a thermosetting resin and an inorganic insulating powder. A precursor sheet in a semi-cured state is prepared by mixing, and the precursor sheet is subjected to appropriate punching, and then a metal paste formed by mixing a thermosetting resin and metal powder is formed into a predetermined pattern. The precursor sheet on which the metal paste is printed and applied is laminated as required, and this is applied for about 100 hours.
Manufactured by thermosetting at a temperature of ３００300 ° C.

[0007]

However, a wiring board comprising an insulating base formed by bonding the inorganic insulating powder with a thermosetting resin and a wiring conductor formed by bonding a metal powder with a thermosetting resin, The bonding strength of the wiring conductor to the insulating base is slightly weak, and when a large external force is applied to the wiring conductor, for example, when connecting an electrode of a semiconductor element to the wiring conductor, the wiring force peels off from the insulating base due to the external force, and the semiconductor element, etc. There is a problem to be solved that the reliability of the electrical connection between the electrode and the wiring conductor is slightly inferior.

The present invention has been made in view of the above-mentioned drawbacks, and has as its object to strengthen the bonding between an insulating base and a wiring conductor and to firmly electrically connect an electrode of a semiconductor element to the wiring conductor. It is to provide a wiring board.

[0009]

The present invention comprises 60 to 95% by weight of an inorganic insulating powder and 5 to 40% by weight of a thermosetting resin. A wiring board comprising: an insulating base made of at least one insulating substrate bonded by a curable resin; and a wiring conductor bonded to a metal powder by a thermosetting resin.
An intermediate layer made of a thermosetting resin is interposed between the insulating base and the wiring conductor, and the thermosetting resin of the intermediate layer is joined to each thermosetting resin of the insulating base and the wiring conductor by a crosslinking reaction. It is characterized by having made it.

The method of manufacturing a wiring board according to the present invention further comprises a step of preparing a precursor sheet obtained by mixing a thermosetting resin precursor and an inorganic insulating powder; A step of applying a resin paste composed of a resin precursor, a step of applying a metal paste obtained by mixing a thermosetting resin precursor and a metal powder on the applied resin paste in a predetermined pattern, The sheet, the resin paste, and the metal paste are subjected to heat treatment while applying pressure, and are thermoset while causing a crosslinking reaction between the thermosetting resin of the thermoresin paste and the thermosetting resin of the precursor sheet and the metal paste. And a process.

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

Further, according to the wiring board of the present invention, an intermediate layer made of a thermosetting resin is interposed between the insulating base and the wiring conductor, and the thermosetting resin of the intermediate layer is applied to each of the insulating base and the wiring conductor. The bonding strength of the wiring conductor to the insulating base becomes extremely strong due to the bonding to the thermosetting resin of the above by a crosslinking reaction. As a result, when the electrode of the semiconductor element is connected to the wiring conductor, a large external force is applied to the wiring conductor. Even when the voltage is applied, the wiring conductor does not peel off from the insulating base, and the electrodes of the semiconductor element and the like can be reliably and firmly electrically connected to the wiring conductor.

Further, the wiring board of the present invention comprises a step of preparing a precursor sheet obtained by mixing a thermosetting resin precursor and an inorganic insulating powder; and a step of forming a thermosetting resin precursor on one surface of the precursor sheet. A step of applying a resin paste comprising: a step of applying a metal paste obtained by mixing a thermosetting resin precursor and a metal powder on the applied resin paste in a predetermined pattern; and Heat-treating while applying pressure to the paste and the metal paste, and performing a thermosetting while causing a cross-linking reaction between the thermosetting resin of the thermo-resin paste and the thermosetting resin of the precursor sheet and the metal paste. Manufactured, thermosetting resin precursors of precursor sheets, resin pastes, and metal pastes hardly shrink during thermosetting, causing deformation and dimensional variations due to uneven shrinkage. And no.

[0014]

Next, the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 show one embodiment of a case where 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 insulating substrate 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 the semiconductor element at the center of the upper surface thereof, and the semiconductor element 3 is provided on the bottom surface of the concave portion 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, for example, silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate,
It is formed by bonding an inorganic insulating powder such as zeolite with a thermosetting resin such as an epoxy resin or a polyimide resin.
a, 1b, and 1c are each formed by bonding an inorganic insulating powder with a thermosetting resin having excellent toughness. Therefore, even if an external force is applied to the insulating base 1, the insulating base 1 is applied to the insulating base 1 by the external force. No chips, cracks, cracks, etc., occur.

The three insulating substrates 1 constituting the 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. Then, a large thermal stress is generated between the two due to a difference in thermal expansion coefficient, and the large thermal stress causes the semiconductor element 3 to be separated from the insulating base 1 or the semiconductor element 3 to be cracked or chipped. I will. 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% by weight to 95% by weight.

The insulating substrate 1 has a wiring conductor 2 formed by bonding metal powders such as copper, silver and gold from a thermosetting resin such as an epoxy resin from the periphery to the lower surface of the concave portion 1d.

The wiring conductor 2 functions to electrically connect the semiconductor element 3 housed therein to an external electric circuit,
Each electrode of the semiconductor element 3 is electrically connected to a peripheral portion of the concave portion 1d via a bonding wire 4, and a portion extending to the lower surface of the insulating base 1 is electrically connected to an external electric circuit board.

When the amount of the metal powder contained in the wiring conductor 2 is less than 70% by weight, the conductivity of the wiring conductor 2 tends to deteriorate, and when the amount exceeds 95% by weight, the metal powder is converted to a thermosetting resin. It tends to be difficult to bond firmly. Therefore, the wiring conductor 2 formed by bonding the metal powder with a thermosetting resin has a metal powder content of 70% by weight to 9% by weight.
It is preferable to set the range to 5% by weight.

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

In the wiring conductor 2, a bump electrode 2a electrically connected to an external electric circuit is formed at a portion extending to the lower surface of the insulating base 1, and the bump electrode 2a is connected to a wiring of the external electric circuit board. The semiconductor element 3 housed inside by joining the conductor to the conductor via a conductive adhesive such as solder is electrically connected to an external electric circuit.

As shown in FIG. 2, an intermediate layer 5 is interposed between the wiring conductor 2 and the upper surface of the insulating substrate 1b constituting the insulating base 1.
When the electrode of the semiconductor element 3 is connected to the wiring conductor 2 via the bonding wire 4 when the external conductor is strongly bonded to the wiring substrate 2, even if a large external force is applied to the wiring conductor 2, the wiring force is applied by the external force. 2 does not peel off from the insulating base 1 (the upper surface of the insulating substrate 1b), whereby each electrode of the semiconductor element 3 can be securely and firmly electrically connected to the wiring conductor 2.

The intermediate layer 5 is made of a thermosetting resin such as a bismaleimide-triazine resin, an epoxy resin, or a polyimide resin.
Crosslinking reaction, specifically, when the thermosetting resin of the intermediate layer 5 is a bismaleimide-triazine resin and the thermosetting resin of the insulating substrate 1b and the wiring conductor 2 is an epoxy resin, The tertiary amine present in the cyanate group, which is the main component of the bismaleimide-triazine resin, acts as ring-opening polymerization of the epoxy group of the epoxy resin of the insulating substrate 1b and the wiring conductor 2 to cause a crosslinking reaction, The wiring conductor 2 is firmly joined to the insulating substrate 1b by causing a crosslinking reaction between -C = O present in the resin and the ethoxy group.

The intermediate layer 5 has a thickness of 10 μm.
If it is less than 70 mm, it will be difficult to firmly join the wiring conductor 2 on the insulating substrate 1b.
There is a risk that separation may occur due to thermal stress due to the difference in thermal expansion coefficient between the wiring conductor 2 and the insulating substrate 1b. Therefore, it is preferable that the thickness of the intermediate layer 5 be in the range of 10 μm to 70 μm.

The intermediate layer 5 has silicon oxide, aluminum oxide, aluminum nitride, silicon carbide,
A filler such as barium titanate, strontium titanate, or titanium oxide may be contained. However, if the content exceeds 50% by weight, the crosslinking reactivity with the thermosetting resin in the wiring conductor 2 and the thermosetting resin in the insulating substrate 1b deteriorates. preferable.

Thus, according to the above-described 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, and each electrode of the semiconductor element 3 is electrically connected to the wiring conductor 2 through the bonding wire 4. After that, the lid 6 is bonded to the upper surface of the insulating base 1 via a sealing agent, and the semiconductor element 3 is hermetically accommodated in a container including the insulating base 11 and the lid 6. Thus, a semiconductor device as a product is obtained.

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. 3A, three precursor sheets 11a, 11b, and 11c are prepared.

The three precursor sheets 11a, 11b,
11c is an epoxy resin made of an inorganic insulating powder such as silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate, strontium titanate, and titanium oxide;
Polyimide resin, formed by bonding with a thermosetting resin precursor such as polyphenylene ether resin, for example, a silicon oxide powder having a particle size of 0.1 to 100 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, and then the paste is formed into a sheet. It is manufactured by heating and semi-curing at a temperature of about 25 to 100 ° C. for 1 to 60 minutes.

Next, as shown in FIG. 3B, a resin paste film 15 serving as an intermediate layer is formed on the upper surface of the precursor sheet 11b.
To form

The resin paste film 15 is made of epoxy resin,
It is formed of a thermosetting resin precursor such as a polyimide resin and a polyphenylene ether resin, and is formed on the upper surface of the precursor sheet 11b by being applied to the upper surface of the precursor sheet 11b to a thickness of 10 μm to 70 μm.

The precursor sheet 1 for the resin paste film 15
1b is formed on the upper surface of the precursor sheet 11b by applying a resin paste composed of a thermosetting resin precursor and heat-treating the resin paste at a temperature of about 25 to 100 ° C. for 1 to 60 minutes. This is performed by semi-curing the curable resin.

Next, as shown in FIG. 3 (c), two precursor sheets 11a, 11b among the three precursor sheets 11a, 11b, 11c form openings 1d for accommodating the semiconductor elements 3 therein. A, A 'are replaced with two precursor sheets 11
b, a through hole B for routing the wiring conductor 2 to 11c,
B ′ are 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 to form the precursor sheets 11a, 11b, 11c.
c is formed by piercing a hole of a predetermined shape in each of c.

Next, as shown in FIG. 3D, 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. Print and apply in a predetermined pattern and heat it at a temperature of about 25-100 ° C for 1-60 minutes,
Semi-cured.

As the metal paste 12, for example,
An epoxy resin such as a bisphenol A type epoxy resin, a novolak type epoxy resin, a glycidyl ester type epoxy resin, and an amine-based curing agent, an imidazole-based curing agent, and an acid anhydride are added to a powder of copper or the like having a particle size of about 0.1 to 20 μm. A paste obtained by adding and mixing a curing agent such as a system curing agent is used.

Finally, the three precursor sheets 11
a, 11b, and 11c are vertically laminated and pressed at a constant pressure (5 to 50 Kgf / cm ² ) from the upper and lower sides to about 80 to 3
A temperature of 00 ° C. is applied for 10 seconds to 24 hours to cause a crosslinking reaction between the thermosetting resin of the resin paste film 15, the thermosetting resin of the precursor sheet 11 b and the thermosetting resin of the metal paste 12, and Body sheets 11a, 11
By completely thermosetting the b, 11c, the resin paste film 15, and the metal paste 12 printed and applied in a predetermined pattern, a wiring board in which the wiring conductor 2 is adhered to the insulating base 1 as shown in FIG. 1 is completed. . In this case, the precursor sheets 11a, 11b, 11c, the resin paste film 15, and the metal paste 12 hardly shrink during thermosetting, and therefore, there is no deformation or dimensional variation in the obtained wiring board. Thus, the semiconductor element and the wiring conductor can be accurately connected.

The three precursor sheets 11a, 11
The pressing of b and 11c from above and below at 5 to 50 kgf / cm ² promotes the crosslinking reaction between the thermosetting resin of the resin paste film 15 and the thermosetting resin of the metal paste 12 and the precursor sheet 11b, and at the same time, When the pressing force is less than 5 kgf / cm ² , the purpose is not sufficiently achieved. When the pressing force exceeds 50 kgf / cm ² , the obtained insulating substrate is greatly deformed and the dimensional accuracy is reduced. It is preferable to set the range to 50 kgf / cm ² .

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 spirit of the present invention. Although the case where the substrate is applied to a semiconductor element housing package for housing a semiconductor element has been described as an example,
Needless to say, this can be applied to a wiring board used for a constituent integrated circuit or the like.

Further, in the above embodiment, the wiring substrate is manufactured by laminating three precursor sheets. However, the wiring substrate may be formed by laminating one, two, or four or more insulating substrates. Good.

[0041]

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 line collides violently, the insulating substrate will not be chipped, cracked or cracked.

Further, according to the wiring board of the present invention, an intermediate layer made of a thermosetting resin is interposed between the insulating base and the wiring conductor, and the thermosetting resin of the intermediate layer is formed on the insulating base and the wiring conductor. The bonding strength of the wiring conductor to the insulating substrate becomes extremely strong because the thermosetting resin is bonded to each thermosetting resin by a cross-linking reaction. As a result, a large external force is applied to the wiring conductor when the electrode of the semiconductor element is connected to the wiring conductor. Is applied, the wiring conductor does not peel off from the insulating base, and the electrodes of the semiconductor element and the like can be securely and firmly electrically connected to the wiring conductor.

Further, the wiring board of the present invention comprises a step of preparing a precursor sheet obtained by mixing a thermosetting resin precursor and an inorganic insulating powder; and a step of forming a thermosetting resin precursor on one surface of the precursor sheet. A step of applying a resin paste comprising: a step of applying a metal paste obtained by mixing a thermosetting resin precursor and a metal powder on the applied resin paste in a predetermined pattern; and Heat-treating while applying pressure to the paste and the metal paste, and performing a thermosetting while causing a cross-linking reaction between the thermosetting resin of the thermo-resin paste and the thermosetting resin of the precursor sheet and the metal paste. Manufactured, thermosetting resin precursors of precursor sheets, resin pastes, and metal pastes hardly shrink during thermosetting, causing deformation and dimensional variations due to uneven shrinkage. And no.

[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 an enlarged sectional view of a main part of the wiring board shown in FIG.

FIGS. 3A to 3D are cross-sectional views for explaining steps of a method for manufacturing a wiring board according to the present invention.

[Description of Signs] 1 ... Insulating substrate 1a, 1b, 1c ... Insulating substrate 2 ... Wiring conductor 5 ... ..Intermediate layers 11a, 11b, 11c..Precursor sheet 12 ... Metal paste 15 ... Resin paste film

Claims (3)

[Claims] At least one of an inorganic insulating powder of 60% by weight to 95% by weight and a thermosetting resin of 5% to 40% by weight, wherein the inorganic insulating powder is bonded by the thermosetting resin. A wiring substrate, comprising a wiring conductor obtained by bonding metal powder with a thermosetting resin to an insulating base made of a plurality of insulating substrates, wherein a thermosetting resin is provided between the insulating base and the wiring conductor. A wiring substrate, wherein an intermediate layer is interposed and the thermosetting resin of the intermediate layer is joined to each thermosetting resin of the insulating base and the wiring conductor by a crosslinking reaction. 2. The intermediate layer has a thickness of 10 μm to 70 μm.
The wiring board according to claim 1, wherein 3. A step of preparing a precursor sheet obtained by mixing a thermosetting resin precursor and an inorganic insulating powder, and applying a resin paste made of a thermosetting resin precursor to one surface of the precursor sheet. And applying a metal paste formed by mixing a thermosetting resin precursor and a metal powder on the applied resin paste in a predetermined pattern, and applying a pressure to the precursor sheet, the resin paste and the metal paste. Heat-treating while applying a thermosetting resin, and thermosetting while causing a crosslinking reaction between the thermosetting resin of the thermo-resin paste and the thermosetting resin of the precursor sheet and the metal paste. Method.