JPH08125291A - Wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a wiring board which is capable of normally and stably operating a semiconductor element housed therein for a long period of time without generating any break or crack, and electrically connecting the semiconductor element to a wiring layer with constant accuracy and security without having deformation like warping and dimensional unevenness. CONSTITUTION: On at least one insulation board 1a-1c which is made of 60-95% by weight of inorganic insulating material powder and 5-40% by weight of thermosetting resin, with the inorganic insulating material powder bonded by the thermosetting resin, a wiring conductor 2 made of metal powder bonded by thermosetting resin is deposited.

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, 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 and mixing an appropriate organic binder, solvent, etc. to the ceramic raw material powder such as calcium oxide to form a slurry and making this into a sheet shape by adopting the conventionally known doctor blade method. After that, the ceramic green sheet is appropriately punched and a metal paste to be a wiring conductor is printed and applied in a predetermined pattern, and finally, the ceramic green sheets are vertically laminated in a predetermined order to form a ceramic molded body. Along with this, the ceramic green body is manufactured by firing 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.

According to the method of manufacturing the wiring board,
When firing the ceramic green body, uneven firing shrinkage occurs in the ceramic green body, resulting in deformation such as warpage and dimensional variation in the obtained wiring board, and as a result, the semiconductor element and wiring conductor are electrically connected. In addition, it has a drawback that it is difficult to connect accurately and surely.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object of the present invention is to operate a semiconductor element housed therein normally and stably for a long period of time without causing cracks or cracks. It is to provide a wiring board that can be used.

Another object of the present invention is a method of manufacturing a wiring board which is capable of electrically connecting a semiconductor element to a wiring conductor easily and accurately and surely without deformation such as warpage or variation in dimensions. To provide.

[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
A thermosetting resin, and a wiring conductor formed by bonding metal powder with a thermosetting resin is attached to at least one insulating substrate obtained by bonding the inorganic insulating powder with the thermosetting resin. It is a feature.

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 precursor being added to the precursor sheet. The present invention is characterized by comprising a step of printing a metal paste formed by mixing a body and a metal powder in a predetermined pattern, and a step of thermally curing the precursor sheet and the metal paste.

[0010]

According to the present invention, since the inorganic insulating material powder serving as the insulating substrate and the metal powder serving as the wiring conductor are bonded by the thermosetting resin having excellent toughness, the wiring boards or the wiring boards and the semiconductor device are automatically manufactured. Even if a part of the line collides violently, the insulating substrate will never be chipped, cracked, or cracked.

Further, according to the present invention, a step of preparing a precursor sheet formed by mixing a thermosetting resin precursor and an inorganic insulating powder, and the thermosetting resin precursor and the metal powder are added to the precursor sheet. Since a wiring board is manufactured by a step of printing a metal paste formed by mixing the above with a predetermined pattern and a step of thermally curing the precursor sheet and the metal paste, deformation and dimensions due to uneven shrinkage accompanying firing. Does not occur.

[0012]

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 insulating substrate 1 is made of a material obtained by bonding inorganic insulating powders such as silicon oxide, aluminum oxide, aluminum nitride, silicon carbide and barium titanate with a thermosetting resin such as epoxy resin or polyimide resin.
A plurality of insulating substrates 1a to 1c are laminated, and a concave portion 1a for accommodating a semiconductor element is formed in the center of the upper surface of the insulating substrate 1a to 1c. The semiconductor element 3 is formed on the bottom surface of the concave portion 1a via an adhesive such as resin. And glued and fixed.

Since the insulating substrates 1a to 1c are formed by bonding inorganic insulating powders with a thermosetting resin having excellent toughness, the insulating substrate 1 is chipped, cracked, or cracked when the wiring substrates collide with each other. Will never occur.

When the content of the inorganic insulating powder contained in the insulating substrates 1a to 1c is less than 60% by weight, the thermal expansion coefficient of the insulating base 1 is compared with that of the semiconductor element 3. Then, when the semiconductor element 3 becomes extremely large and heat generated when the semiconductor element 3 is operated is applied, a large thermal stress is generated due to the difference in thermal expansion coefficient between the two, and the semiconductor element 3 is separated from the insulating substrate 1, The semiconductor element 3 tends to be cracked, and if it exceeds 95% by weight, it tends to be difficult to firmly bond the inorganic insulating powder with the thermosetting resin. Therefore, the content of the inorganic insulating powder contained in the insulating substrates 1a to 1c is specified in the range of 60 to 95% by weight.

A wiring conductor 2 is formed by depositing a metal powder of copper, silver, gold or the like with a thermosetting resin such as an epoxy resin from the periphery of the recess 1a to the lower surface of the insulating substrate 1.

The wiring conductor 2 serves 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 the peripheral portion of the recess 1a through a bonding wire 4.

When the content of the metal powder contained in the wiring conductor 2 is less than 70% by weight, the conductivity of the wiring conductor tends to deteriorate, and when it exceeds 95% by weight, the metal powder is hardened with resin. It tends to be difficult to combine with. Therefore, the content of the metal powder contained in the wiring conductor 2 is preferably in the range of 70 to 95% by weight.

Further, the wiring conductor 2 may be 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 1.0 to 20.0 μm. It is possible to effectively prevent oxidative corrosion of the wiring conductor 2 and the wiring conductor 2 and the bonding wire 4
Can be firmly and electrically connected. Therefore,
Usually, on the exposed surface of the wiring conductor 2, a metal such as nickel or gold having excellent corrosion resistance and good conductivity is layered to a thickness of 1.0 to 20.0 μm by a plating method, if necessary. .

The wiring conductor 2 also has a bump electrode 2a which is electrically connected to an external electric circuit formed at a portion led out to the lower surface of the insulating substrate 1. The bump electrode 2a is connected to the wiring of the external electric circuit board. By joining the conductor to the conductor via a conductive joining material such as solder, the semiconductor element 3 housed inside is electrically connected to the external electric circuit.

Thus, according to the wiring board of the present invention, the semiconductor element 3 is adhered and fixed to the bottom surface of the recess 1a of the insulating substrate 1, and each electrode of the semiconductor element 3 is electrically connected to the wiring conductor 2 via the bonding wire 4. Then, finally, the lid 5 is bonded to the upper surface of the insulating substrate 1 through a sealing material to obtain a semiconductor device as a product.

Next, a method of manufacturing the wiring board applied to the semiconductor element housing package will be described in detail.
First, as shown in FIG. 2A, precursor sheets 11a to 11 formed by bonding inorganic insulating powders with a thermosetting resin precursor.
Prepare c.

The precursor sheets 11a to 11c have a particle size of, for example, when the inorganic insulating powder contained in the insulating substrates 1a to 1c is made of silicon oxide and the thermosetting resin for binding the same is made of an epoxy resin. Epoxy resin such as bisphenol A type epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin, etc. and silicon oxide powder of about 0.1 to 100 μm and amine type curing agent, imidazole type curing agent, acid anhydride type curing agent, etc. The paste obtained by adding and mixing the curing agent and the like 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 precursor sheets 11a to 11c are led out when the openings A and A'to be the recesses 1a and the wiring conductor are led out from the periphery of the recesses 1a of the insulating substrate 1 to the lower surface. The through-holes B and B'which serve as passages are formed by using a conventionally known punching method.

Next, as shown in FIG. 2 (c), the metal paste 12 to be the wiring conductor 2 is formed on the upper and lower surfaces of the precursor sheets 11a to 11c and in the through holes B and B'by the conventional screen printing method and the well-known method. The filling method is applied to form a predetermined pattern by printing, and at a temperature of about 25 to 100 ° C., 1 to 6
Heat for 0 minutes to semi-cure.

The metal paste 1 to be the wiring conductor 2
2 is, for example, when the metal powder contained in the wiring conductor 2 is made of copper and the thermosetting resin that binds it is made of an epoxy resin, bisphenol A type powder is added to copper powder having a particle size of about 0.1 to 20 μm. It is manufactured by adding and mixing an epoxy resin such as an epoxy resin, a novolac type epoxy resin, and a glycidyl ester type epoxy resin, and an amine curing agent, an imidazole curing agent, an acid anhydride curing agent, and the like.

Finally, the precursor sheets 11a to 11c, on which the metal paste 12 is printed and applied in a predetermined pattern, are vertically laminated and heated at a temperature of about 80 to 300 ° C. for about 10 seconds to 24 hours. Sheets 11a-11
The wiring board shown in FIG. 1 is manufactured by completely thermosetting c and the metal paste 12. When the insulating base 1 is manufactured by thermosetting the precursor sheets 11a to 11c and the metal paste 12, the precursor paste sheets 11a to 11c to be the insulating base 1 and the metal paste 12 to be the wiring conductor 2 are thermoset. There is almost no contraction, and therefore, there is almost no occurrence of deformation or dimensional variation in the insulating substrate 1.

Thus, according to the manufacturing method of the present invention, it is possible to provide the wiring substrate in which the insulating substrate 1 does not have deformation or variation in dimensions.

The present invention is not limited to the above-described embodiments. For example, in the above-mentioned embodiments, the case where the wiring board of the present invention is applied to a semiconductor element housing package for housing semiconductor elements will be described. However, it goes without saying that the wiring board of the present invention can be applied as a wiring board used in, for example, a hybrid integrated circuit.

Further, in the above-mentioned embodiment, the wiring board is manufactured by laminating the three precursor sheets, but the wiring board is formed by laminating one, two or four or more precursor sheets. May be made.

Further, in the above-mentioned embodiment, the wiring substrate is formed of the insulating substrates containing the same inorganic insulating powder, but the insulating substrates constituting the wiring substrate contain different inorganic powders. It may be.

[0032]

EFFECTS OF THE INVENTION According to the wiring board of the present invention, since the inorganic insulating material powder to be the insulating board and the metal powder to be the wiring conductor are combined by the thermosetting resin having excellent toughness, the wiring boards are interconnected or the wiring boards are Even if a part of the semiconductor device manufacturing line violently collides with each other, the insulating substrate is never chipped, cracked, or cracked, so that the semiconductor element can be operated normally and stably for a long period of time.

Further, according to the present invention, a step of preparing a precursor sheet formed by mixing a thermosetting resin precursor and an inorganic insulating powder, and the thermosetting resin precursor and the metal powder are added to the precursor sheet. Since a wiring board is manufactured by a step of printing a metal paste formed by mixing the above with a predetermined pattern and a step of thermally curing the precursor sheet and the metal paste, deformation and dimensions due to uneven shrinkage accompanying firing. Therefore, the semiconductor element can be accurately and surely electrically connected to 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]

 1 ... Insulating substrate 1a to 1c ... Insulating substrate 2 ... Wiring conductor 11 ... 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, and at least one insulating substrate having the inorganic insulating powder bonded with the thermosetting resin is coated with a wiring conductor having metal powder bonded with the thermosetting resin. A wiring board made up of: 2. A step of preparing a precursor sheet formed by mixing a thermosetting resin precursor and an inorganic insulating powder, and mixing the thermosetting resin precursor and a metal powder in the precursor sheet. A method of manufacturing a wiring board, comprising: a step of printing the formed metal paste in a predetermined pattern; and a step of thermally curing the precursor sheet and the metal paste.