JPH10163380A - Manufacture of wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the chipping, cracking, etc., of an insulating substrate even when a wiring board violently comes into collision with another wiring board or part of a semiconductor device. SOLUTION: When a wiring board is constituted by forming wiring conductors 2 formed by coupling metallic particles with a thermosetting resin on an insulating substrate 1 formed by coupling 60-95wt.% inorganic insulator powder with 5-40wt.% thermosetting resin, the surfaces of the metallic particles in the conductors 2 are coated with a silane coupling agent. When the surfaces of the metallic particles are coated with the coupling agent, the coupling between the metallic particles and thermosetting resin in the conductors 2 become extremely strong and part of the conductors 2 is not separated from the conductors nor peeled off from the substrate 1.

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 device housing package for housing a semiconductor element, a hybrid integrated circuit board, and the like, and a method of manufacturing the same.

[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 such as tungsten or molybdenum which is led from the periphery of the recess to the lower surface of the insulating base. The electrodes of the semiconductor element are electrically fixed to the wiring conductor through an electrical connection means such as a bonding wire, and then the cover is made of metal, ceramic, or the like. The body is joined to the upper surface of the insulating substrate with a sealing material such as glass, resin, brazing material, etc. A semiconductor device as a product is obtained by hermetically housing the semiconductor element in the unit, and a portion of the wiring conductor led out to the lower surface of the insulating base is connected to the wiring conductor of the external electric circuit board via an electrical connection means such as solder. Thus, each electrode of the semiconductor element housed in the concave portion of the insulating base is electrically connected to the external electric circuit board.

[0003] This conventional wiring board is manufactured by, for example, a ceramic green sheet laminating method.
A ceramic powder such as aluminum oxide, silicon oxide, magnesium oxide, or calcium oxide is mixed with a suitable organic binder, a solvent, and the like to form a slurry, which is then formed into a sheet by using a conventionally known doctor blade method. By obtaining multiple ceramic green sheets,
Thereafter, a predetermined 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, and finally, these ceramic green sheets are laminated in a predetermined order to form a green ceramic molded body. The green ceramic molded body is manufactured by firing at a high temperature of about 1600 ° C. in a reducing atmosphere.

However, in this 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 semiconductor device manufacturing automatic 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 cannot be used for a long time. There was a drawback that normal and stable operation could not be achieved.

Further, according to the method for manufacturing a wiring board as described above, when the green ceramic molded body is fired, uneven firing shrinkage occurs in the green ceramic molded body, and the obtained wiring board is deformed such as warpage. As a result, it is difficult to accurately and reliably electrically connect each electrode of the semiconductor element and the wiring conductor or the wiring conductor and the wiring conductor of the external electric circuit board. Had the disadvantage that

On the other hand, the insulating substrate of the wiring board is formed of a material obtained by bonding inorganic insulating powder with a thermosetting resin instead of the conventional ceramics, and the wiring conductor is formed of a metal instead of the conventional refractory metal metallization. There has been proposed a wiring board formed of a material in which powder is bonded with a thermosetting resin.

A wiring board composed of an insulating base formed by bonding an inorganic insulating powder with a thermosetting resin and a wiring conductor formed by bonding a metal powder with a thermosetting resin is composed of a thermosetting resin precursor and an inorganic hardening resin. Prepare a precursor sheet in a semi-cured state by mixing with an insulating powder, perform appropriate punching on a given precursor sheet, and then mix a thermosetting resin precursor and metal powder with this. The metal paste is printed and applied in a predetermined pattern, and finally, the precursor sheet on which the metal paste is printed and applied is laminated as necessary and thermally cured at a temperature of about 100 to 300 ° C. You.

[0008]

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 between the metal powder constituting the wiring conductor and the thermosetting resin is slightly weak, and when a large external force is applied to the wiring conductor when connecting the electrodes of the semiconductor element to the wiring board, the external force causes the thermosetting resin to harden. The solution is that the reliability of the electrical connection between the electrodes such as semiconductor elements and the wiring conductors is slightly inferior because a part of the wiring conductors is separated from the wiring conductors due to the disconnection of the metal powders by the resin and separated from the wiring base. Had to be done.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to combine an insulating base formed by bonding an inorganic insulating powder with a thermosetting resin and a metal powder with a thermosetting resin. A wiring board made up of a wiring conductor made of a semiconductor device and a wiring conductor is not separated from the wiring conductor even when a large external force is applied, and the electrodes of the semiconductor element to be mounted are securely and firmly electrically connected to the wiring conductor. And a method of manufacturing the same.

[0010]

According to the present invention, there is provided a wiring board comprising:
A wiring board formed by applying a wiring conductor formed by bonding a metal powder with a thermosetting resin to an insulating base formed by bonding 5 to 40% by weight of an inorganic insulating powder with a thermosetting resin of 5 to 40% by weight. In addition, the surface of the metal powder is coated with a silane coupling agent.

In the wiring board according to the present invention, the coating amount of the silane coupling agent with respect to the metal powder is 0.1 to 5.0% by weight.

Further, a method of manufacturing a wiring board according to the present invention comprises mixing a thermosetting resin precursor and an inorganic insulating powder.
A step of preparing a precursor sheet to be an insulating substrate after curing; and mixing a thermosetting resin precursor and a metal powder whose surface is coated with a silane coupling agent. The method includes a step of printing and applying the precursor sheet in a predetermined pattern, and a step of thermally curing 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 the thermosetting resin having excellent toughness, the wiring boards are connected to each other or the wiring board and the semiconductor device manufacturing line. Even if a part of the insulating substrate collides violently, chipping, cracking or cracking of the insulating substrate does not occur.

Further, according to the wiring board of the present invention, the surface of the metal powder constituting the wiring conductor is coated with a silane coupling agent having a strong binding property to both the metal powder and the thermosetting resin. The bonding between the metal powder in the conductor and the thermosetting resin becomes extremely strong. As a result, even when a large external force is applied to the wiring conductor when connecting the electrode of the semiconductor element to the wiring conductor, a part of the wiring conductor is Is not separated from the wiring conductor and does not peel off from the insulating base, so that electrodes of a semiconductor element or the like can be securely and firmly electrically connected to the wiring conductor.

Further, according to the method of manufacturing a wiring board of the present invention, there is provided a step of preparing a precursor sheet which is a mixture of a thermosetting resin precursor and an inorganic insulating powder and which becomes an insulating substrate after curing; Printing a metal paste to be a wiring conductor after curing in a predetermined pattern on the precursor sheet, comprising mixing a hard resin precursor and a metal powder whose surface is coated with a silane coupling agent; and And the step of thermally curing the metal paste, so that the thermosetting resin precursor of the precursor sheet or the metal paste hardly shrinks at the time of thermosetting, so that deformation and dimensions due to uneven shrinkage are caused. Does not occur on the wiring board.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment in which a wiring board according to the present invention is applied to a semiconductor element housing package for housing a semiconductor element. In FIG. 1, 1 is an insulating base, and 2 is a wiring conductor. Reference numeral 3 denotes a semiconductor element.

The insulating substrate 1 in this embodiment is formed by laminating three insulating substrates 1a, 1b and 1c, and has a concave portion 1d for accommodating a semiconductor element in the center of the upper surface thereof. The semiconductor element 3 is bonded and fixed to the bottom of the recess 1d via an adhesive such as a resin.

The insulating substrates 1a and 1b constituting the insulating base 1
1c is a powder of an inorganic insulating material such as silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate, strontium titanate, calcium titanate, titanium oxide, zeolite, epoxy resin, polyimide resin, phenol resin, heat It is formed by bonding with a thermosetting resin such as a curable polyphenylene ether resin, a polyimide amide resin, and a bismaleimide triazine resin. Since the inorganic insulating powder is formed by bonding the inorganic insulating powder with a thermosetting resin such as an epoxy resin having excellent toughness, even if an external force is applied to the insulating base 1, the insulating base 1 may be chipped or cracked by the external force.
There is no crack or the like.

It is to be noted that three insulating substrates 1a and 3a constituting an insulating base 1 formed by bonding inorganic insulating powder with a thermosetting resin.
1b and 1c are such that if the content of the inorganic insulating powder contained therein is less than 60% by weight, the thermal expansion coefficient of the insulating base 1 is significantly different from the thermal expansion coefficient of the semiconductor element 3.
When the semiconductor element 3 emits heat during operation and this heat is applied to both the semiconductor element 3 and the insulating base 1, a large thermal stress is generated between the two due to a difference in the coefficient of thermal expansion between the two. The stress tends to cause the semiconductor element 3 to peel off from the insulating base 1 or cause the semiconductor element 3 to crack or chip. On the other hand, the content of the inorganic insulating powder is 95% by weight.
When the ratio exceeds the above, it tends to be difficult to form a predetermined insulating substrate 1 by firmly bonding the inorganic insulating powder with a thermosetting resin. Therefore, the insulating substrate 1a constituting the insulating base 1
It is necessary to set the amount of the inorganic insulating powder contained in each of 1b and 1c in the range of 60 to 95% by weight.

The insulating substrate 1 is coated with a metal powder such as copper, silver, a copper-silver-copper alloy or gold whose surface is coated with silver from the periphery of the concave portion 1d to the lower surface thereof by thermosetting epoxy resin or the like. The wiring conductor 2 joined by the resin is formed.

The wiring conductor 2 functions to electrically connect each electrode of the semiconductor element 3 to an external electric circuit. Each electrode of the semiconductor element 3 is bonded to a portion of the insulating base 1 located around the concave portion 1d. A portion electrically connected via the wire 4 and a portion led out to the lower surface of the insulating base 1 is electrically connected to an external electric circuit via an electric connection means such as solder.

The metal powder contained in the wiring conductor 2 acts to impart conductivity to the wiring conductor 2. When the content in the wiring conductor 2 is less than 70% by weight, the electric resistance of the wiring conductor 2 becomes high. If it exceeds 95% by weight, it tends to be difficult to form a predetermined wiring conductor 2 by firmly bonding the metal powder with a thermosetting resin. Therefore, the amount of metal powder contained in the wiring conductor 2 is
It is preferable to set it in the range of 70 to 95% by weight.

Further, in the wiring board of the present invention, the metal powder contained in the wiring conductor 2 is made of a silane such as aminopropyltrimethoxysilane or glycidoxypropyltrimethoxysilane / methacryloxypropyltrimethoxysilane. It is characterized by being coated with a coupling agent.

The silane coupling agent that coats the surface of the metal powder acts to firmly bind the metal powder and the thermosetting resin via the silane coupling agent, and is included in the silane coupling agent. The silanol group formed by hydrolysis of the alkoxy group is chemically and physically strongly bonded to the metal powder, and the organic reactive group contained in the silane coupling agent and the organic reactive group contained in the thermosetting resin Is strongly bonded by a chemical bond, so that the metal powder in the wiring conductor 2 and the thermosetting resin are extremely strongly bonded.

When the coating amount of the silane coupling agent for coating the metal powder is less than 0.1% by weight with respect to the metal powder, the metal powder in the wiring conductor and the thermosetting resin are extremely separated via the silane coupling agent. When the content exceeds 5.0% by weight, the flow of the metal paste when printing and applying the metal paste to be the wiring conductor 2 to the precursor sheet to be the insulating substrate 1 will be described below if it exceeds 5.0% by weight. This tends to result in poor properties, making it difficult to accurately print and apply a predetermined pattern. Therefore, the coating amount of the silane coupling agent for coating the metal powder is preferably in the range of 0.1 to 5.0% by weight based on the metal powder.

Further, the thermosetting resin contained in the wiring conductor 2 serves to bind the metal powder contained in the wiring conductor 2 and to adhere the wiring conductor 2 to the insulating base 1.
When the content in the wiring conductor 2 is less than 5% by weight, it tends to be difficult to form the wiring conductor 2 by firmly bonding the metal powders to each other.
Tend to have a large electric resistance. Therefore, the content of the thermosetting resin contained in the wiring conductor 2 is 5 to 30.
It is preferably in the range of% by weight.

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

Thus, according to the wiring board of the present invention, 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 connected to the wiring conductor via the bonding wire 4. 2, and then the lid 5 is joined to the upper surface of the insulating substrate 1 with a sealing material made of resin or the like so as to cover the concave portion 1d. A semiconductor device as a product is completed by housing the semiconductor element 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. FIGS. 2A to 2C are exploded cross-sectional views for respective steps illustrating an example of a method for manufacturing a wiring board according to the present invention.

First, as shown in FIG. 2A, three precursor sheets 11a, 11b, and 11c, which are formed by bonding an inorganic insulating powder with a thermosetting resin precursor and serve as an insulating base after curing, are formed. prepare.

The three precursor sheets 11a, 11b, 11
c is, for example, an inorganic insulating powder such as silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate, strontium titanate, and titanium oxide, epoxy resin, polyimide resin, thermosetting polyphenylene ether resin, bismaleimide triazine resin It is formed by bonding with a precursor of a thermosetting resin such as, for example, a silicon oxide powder having a particle size of about 0.1 to 100 μm, a bisphenol A epoxy resin, a bisphenol F epoxy resin, a novolak epoxy resin, A paste obtained by adding and mixing a thermosetting resin such as a glycidyl ester type epoxy resin and a curing agent such as an amine-based curing agent, an imidazole-based curing agent and an acid anhydride-based curing agent is subjected to a sheet forming method such as a doctor blade method. Approximately 25 ~ 10 with sheet form
Manufactured by semi-curing at a temperature of 0 ° C.

Next, as shown in FIG. 2B, two precursor sheets out of the three precursor sheets 11a, 11b and 11c are used.
Openings A and A 'to be recesses 1d are formed in 11a and 11b, and through holes B and B' for routing the wiring conductor 2 are formed in the two precursor sheets 11b and 11c.

The openings A and A 'and the through holes B and B'
Is formed, for example, by subjecting the precursor sheets 11a, 11b, and 11c to a well-known punching method, and punching holes of a predetermined shape in each of them.

Next, as shown in FIG. 2C, the upper and lower surfaces of the semi-cured precursor sheets 11b and 11c and the through holes B and
In B ′, a metal paste 12 which becomes the wiring conductor 2 after curing is printed and applied in a predetermined pattern by using a conventionally known screen printing method and a filling method, and this is applied at about 25 to 100 ° C.
And semi-cured at a temperature of about 1 to 60 minutes.

As the metal paste 12, for example, the surface is coated with a silane coupling agent such as aminopropyltrimethoxysilane or glycidoxypropyltrimethoxysilane / methacryloxypropyltrimethoxysilane and has a particle size of about 0.1 to 20 μm. Epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, glycidyl ester type epoxy resin etc. and amine type curing agent, imidazole type curing agent, acid anhydride type curing agent etc. A paste obtained by adding and mixing a curing agent such as an agent is used.

In order to coat the metal powder with a silane coupling agent, a method of immersing the metal powder in a solution in which the silane coupling agent is dissolved in a solvent such as methanol and then drying the same is adopted. You.

Then, the three semi-cured precursor sheets 11a, 11b, 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 precursor sheet 11a. A wiring board having a wiring conductor 2 adhered to an insulating base 1 as shown in FIG. 1 is obtained by thermally curing a metal paste 12 printed and applied in a predetermined pattern on the precursor sheets 11b and 11c and the precursor sheets 11b and 11c. Complete. in this case,
The precursor sheets 11a, 11b, 11c and the metal paste 12 hardly shrink during thermosetting, and therefore, there is almost no deformation or dimensional variation in the obtained wiring board. The wiring conductor 2 can be accurately connected.

It should be noted that the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist of the present invention. For example, in the above embodiment, the case where the wiring board of the present invention is applied to a semiconductor element housing package for housing a semiconductor element has been described as an example. However, for example, wiring used for other purposes, such as a hybrid integrated circuit. It may be applied to a substrate.

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

Further, in the above-described embodiment, the insulating base is made of the inorganic insulating powder and the thermosetting resin. However, the insulating base is further made of glass fiber, carbon fiber, aramid fiber, alumina fiber, potassium titanate whisker, Short fibers such as aluminum borate whiskers may be blended.

Further, in the above-described embodiment, the wiring conductor is formed by bonding metal powder with a thermosetting resin. The wiring conductor may be formed by combining powders. In this case, a low-melting-point metal powder composed of, for example, tin-lead solder or the like is blended as a low-melting-point metal in a metal paste to be a wiring conductor, and the resultant is printed and applied to a precursor sheet to be an insulating base, and then heated. If a method of applying pressure as needed to melt the low-melting metal powder and bonding the metal powder with the melted low-melting metal is adopted, the electrical connection between the metal powders becomes reliable and strong. Thus, the electric resistance of the wiring conductor can be extremely reduced.

[0042]

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 or the wiring board and the semiconductor device are formed. Even if a part 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, the surface of the metal powder constituting the wiring conductor is coated with a silane coupling agent having a strong binding property to both the metal powder and the thermosetting resin. The bonding between the metal powder in the conductor and the thermosetting resin becomes extremely strong. As a result, even when a large external force is applied to the wiring conductor when connecting the electrode of the semiconductor element to the wiring conductor, a part of the wiring conductor is Is not separated from the wiring conductor or peeled off from the insulating base, and the electrodes of the semiconductor element or the like mounted on the wiring substrate 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 to be an insulating substrate after curing by mixing a thermosetting resin precursor and an inorganic insulating powder; Mixing a metal powder coated with a silane coupling agent with a metal powder, which is to be a wiring conductor after curing, and printing the metal paste on the precursor sheet in a predetermined pattern, and thermally curing the precursor sheet and the metal paste. Since the thermosetting resin precursor of the precursor sheet and the metal paste hardly shrinks at the time of thermosetting, the wiring board may be deformed due to non-uniform shrinkage and dimensional variations may occur. Nor.

[Brief description of the drawings]

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

FIGS. 2 (a) to 2 (c) are exploded cross-sectional views for respective steps showing an example of a method of manufacturing a wiring board according to the present invention.

[Description of Signs] 1 ... Insulating base 2 ... Wiring conductors 11a, 11b, 11c ... Precursor sheet 12 ... ..... Metal paste

Claims (3)

[Claims] 1. A wiring conductor formed by bonding a metal powder with a thermosetting resin to an insulating substrate formed by bonding 60 to 95% by weight of an inorganic insulating powder with a thermosetting resin of 5 to 40% by weight. A wiring board, comprising: a metal powder coated on a surface thereof with a silane coupling agent. 2. The wiring board according to claim 1, wherein the coating amount of the silane coupling agent with respect to the metal powder is 0.1 to 5.0% by weight. 3. A step of preparing a precursor sheet which is a mixture of a thermosetting resin precursor and an inorganic insulating powder and which becomes an insulating substrate after curing; and a step of preparing a thermosetting resin precursor and a silane coupling agent on the surface. Mixed with a metal powder coated with
A method for manufacturing a wiring board, comprising: a step of printing and applying a metal paste to become a wiring conductor after curing in a predetermined pattern on the precursor sheet; and a step of thermally curing the precursor sheet and the metal paste.