JP3145620B2 - 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; Bisphenol is applied to the insulating substrate of the insulating substrate formed by laminating a plurality of insulating substrates obtained by semi-curing, laminating a plurality of the substrates, and thermosetting, and laminating the inorganic insulating powder by the thermosetting resin. A metal formed by bonding metal powders having melting points of 250 ° C. or less to each other in a resin body formed by thermosetting a thermosetting resin precursor composed of an A-type epoxy resin and an acid anhydride-based cured product. A wiring conductor including a member is adhered.

Further, according to the method for producing a wiring board of the present invention, there is provided a step of preparing a precursor sheet obtained by mixing a thermosetting resin precursor and an inorganic insulating powder, and adding a bisphenol A type epoxy resin to the precursor sheet. Printing a metal paste formed by adding and mixing a metal powder having a melting point of 250 ° C. or less to a thermosetting resin precursor composed of an acid anhydride-based curing agent and a predetermined pattern; Heating and thermosetting the thermosetting resin precursor of the precursor sheet and the curable resin precursor of the metal paste while bonding the metal powders in the metal paste to each other. It is.

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, a metal paste obtained by adding a metal powder having a melting point of 250 ° C. or less to a thermosetting resin precursor composed of a bisphenol A type epoxy resin and an acid anhydride-based curing agent and mixing them. When heat-treated to form a wiring conductor, the thermosetting resin precursor composed of bisphenol A type epoxy resin and acid anhydride-based curing agent has a slow thermosetting and promotes fusion bonding between metal powders. With this effect, the mutual joining of the metal powders is completed, and as a result, the electrical resistance of the wiring conductor can be reduced.

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, wherein the precursor sheet comprises a bisphenol A type epoxy resin and an acid anhydride. A step of printing a metal paste formed by adding and mixing a metal powder having a melting point of 250 ° C. or less to a thermosetting resin precursor composed of a system curing agent and a predetermined pattern,
Heating the precursor sheet and the metal paste, and thermally curing the thermosetting resin precursor of the precursor sheet and the curable resin precursor of the metal paste while bonding the metal powder in the metal paste to each other. Since the wiring substrate is manufactured, deformation and dimensional variation due to uneven shrinkage due to firing do not occur.

[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.

A wiring conductor 2 is formed on the insulating base 1 from the periphery of the concave portion 1d to the lower surface. The wiring conductor 2 is made of a tin-lead eutectic solder or the like and has a melting point of 250 ° C. or less. It is composed of a metal member formed by melting and joining powders to each other and 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 composed of a metal member formed by melting and joining low-melting metal powders having a melting point of 250 ° C. or less to each other and a thermosetting resin. Since they are joined to each other, the electric resistance of the wiring conductor 2 is low.

The total amount of the low-melting metal powder contained in the wiring conductor 2 is based on the total weight of the wiring conductor 2.
If the content is less than 70% by weight, it becomes difficult to join the low melting point metal powders, and the electric resistance of the wiring conductor 2 tends to increase.
Tends to be difficult to firmly adhere to the surface. Therefore, it is preferable that the total amount of the low melting point metal powder contained in the wiring conductor 2 is in the range of 70% by weight to 95% by weight based on the total weight of the wiring conductor 2.

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 such as a resin, and the respective electrodes of the semiconductor element 3 are wired via the bonding wires 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 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. 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. It is manufactured by printing and applying a predetermined pattern and heating it at a temperature of about 25 to 100 ° C. for 1 to 60 minutes to make it semi-cured.

As the metal paste 12, for example, a low melting point metal powder made of a eutectic solder of lead-tin having an average particle size of about 0.1 μm to 50 μm, a bisphenol A type epoxy resin and an acid anhydride hardener are used. A paste obtained by adding and mixing a thermosetting resin precursor consisting of

When the average particle diameter of the low melting point metal powder contained in the metal paste 12 is less than 0.1 μm, the low melting point metal powder is agglomerated and cannot be uniformly dispersed. It tends to be difficult to set the width of the wiring conductor 2 to a generally required range of 50 μm to 200 μm. Therefore, it is preferable that the low melting point metal powder contained in the metal paste 12 has an average particle diameter in a range of 0.1 μm to 50 μm.

Finally, the three precursor sheets 11
a, 11b, and 11c are stacked one on top of the other and heated at a temperature of about 300 ° C. for about 10 seconds to 24 hours to bond the low melting point metal powders in the metal paste 12 to each other while precursor sheets 11a and 11b are bonded together. , 11c, and the thermosetting resin precursor of the metal paste 12 printed and applied in a predetermined pattern on the precursor sheets 11b, 11c as shown in FIG. A wiring substrate used for a semiconductor element storage package in which a wiring conductor 2 is attached to an insulating base 1 is completed. In this case, the thermosetting resin precursor composed of the bisphenol A-type epoxy resin and the acid anhydride-based curing agent of the metal paste 12 has an effect as a flux that slowly cures heat and promotes fusion bonding between metal powders. Due to this, the mutual joining of the low melting point metal powders is completed, and as a result, the electric resistance of the wiring conductor 2 can be reduced. At the same time, the precursor sheets 11a, 11b, 11c and the metal paste 12 hardly shrink during thermosetting, so that the resulting wiring board is not deformed or varied in size, and the wiring conductor 2 is disconnected. Without this, the electrodes of the semiconductor element 3 and the like can be reliably electrically connected to the external electric circuit via the wiring conductor 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 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-described embodiment, a wiring board is manufactured by laminating three precursor sheets. However, a wiring board is manufactured using one, two, or four or more precursor sheets. You may.

[0031]

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.

According to the wiring board of the present invention, a metal paste obtained by adding a metal powder having a melting point of 250 ° C. or less to a thermosetting resin precursor composed of a bisphenol A type epoxy resin and an acid anhydride-based curing agent is mixed. When heat-treated to form a wiring conductor, the thermosetting resin precursor composed of bisphenol A type epoxy resin and acid anhydride-based curing agent has a slow thermosetting and promotes fusion bonding between metal powders. With this effect, the mutual joining of the metal powders is completed, and as a result, the electrical resistance of the wiring conductor can be reduced.

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 step of forming a bisphenol A type epoxy resin and an acid anhydride on the precursor sheet. A step of printing a metal paste formed by adding and mixing a metal powder having a melting point of 250 ° C. or less to a thermosetting resin precursor composed of a system curing agent and a predetermined pattern,
Heating the precursor sheet and the metal paste, and thermally curing the thermosetting resin precursor of the precursor sheet and the curable resin precursor of the metal paste while bonding the metal powder in the metal paste to each other. Since the wiring substrate is manufactured, deformation and dimensional variation due to uneven shrinkage due to firing do not occur.

[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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 1/09 H01L 23/14 H05K 1/03 610 H05K 3/00

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 base, a bisphenol A type epoxy resin And a melting point of 250 in a resin body formed by thermosetting a thermosetting resin precursor composed of
A wiring board on which a wiring conductor including a metal member formed by bonding metal powders at a temperature of not more than ° C to each other is adhered. 2. A step of preparing a precursor sheet comprising a mixture of a thermosetting resin precursor and an inorganic insulating powder, wherein the precursor sheet comprises a bisphenol A type epoxy resin and an acid anhydride curing agent. Melting point of the thermosetting resin precursor
Printing a metal paste formed by adding and mixing a metal powder at a temperature of not more than 0 ° C. or less, heating the precursor sheet and the metal paste, and bonding the metal powder in the metal paste to each other while bonding the metal powder in the metal paste. A step of thermally curing the thermosetting resin precursor and the curable resin precursor of the metal paste.