JP3393760B2 - Wiring board and method of manufacturing the same - Google Patents

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 a semiconductor element, a hybrid integrated circuit board and 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 the semiconductor element is housed in the center of its upper surface. And a wiring conductor made of a refractory metal metallization such as tungsten or molybdenum led out from the periphery of the recess of the insulating substrate to the lower surface,
The semiconductor element is provided on the bottom surface of the recess of the insulating substrate with glass, resin,
The electrodes of the semiconductor element are electrically connected to a wiring conductor through an electrical connection means such as a bonding wire while being fixedly adhered through an adhesive such as a brazing material, and then, on the upper surface of the insulating substrate. , A lid made of metal, ceramics or the like is bonded via a sealing material such as glass, resin or brazing material so as to close the recess of the insulating base, and the semiconductor element is hermetically housed in the recess of the insulating base. The product becomes a semiconductor device, and each electrode of the semiconductor element is electrically connected to the external electric circuit board by connecting the part of the wiring conductor led out to the bottom surface of the recess of the insulating base to the wiring conductor of the external electric circuit board. Becomes

This conventional wiring board is manufactured by a ceramic green sheet laminating method. Specifically, an organic binder suitable for ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide,
A plurality of ceramic green sheets are obtained by adding and mixing a solvent, etc. to form a slurry and making it into a sheet shape by adopting the conventionally known doctor blade method, and then suitable punching processing to the ceramic green sheet. And a metal paste serving as a wiring conductor is printed and applied in a predetermined pattern, and finally the ceramic green sheets are laminated in a predetermined order on top and bottom to form a green ceramic molded body, and the green ceramic molded body is reduced to about 1600 in a reducing atmosphere. It is manufactured by firing at a high temperature of ℃.

However, in this conventional wiring board, since the ceramics such as the aluminum oxide sintered body forming the insulating substrate has a hard and brittle property, the wiring boards may not be connected to each other in a carrying process or an automatic line for manufacturing a semiconductor device. Or, if the wiring board and a part of the automatic production line for semiconductor devices collide violently, the insulating substrate may be chipped, cracked, or cracked. As a result, the semiconductor element cannot be hermetically housed and the semiconductor element is long. It has a drawback that it cannot operate normally and stably over a period of time.

According to the method of manufacturing the wiring board,
When firing the green ceramic compact, uneven firing shrinkage occurs in the raw ceramic compact, resulting in deformation such as warpage and dimensional variation in the obtained wiring board, and as a result, each electrode and wiring of the semiconductor element There is a drawback in that it is difficult to electrically connect the conductor or the wiring conductor and the wiring conductor of the external electric circuit board accurately and surely.

Therefore, the insulating substrate of the wiring board is formed of a material in which an inorganic insulating powder is bonded with a thermosetting resin in place of the conventional ceramics, and the wiring conductor is replaced with the conventional refractory metallization and the metal powder is heated. A wiring board formed of a material bonded with a curable resin has been proposed.

A wiring board composed of an insulating substrate formed by bonding the inorganic insulating powder with a thermosetting resin and a wiring conductor formed by bonding the metal powder with the thermosetting resin is a thermosetting resin and an inorganic insulating material. A semi-cured precursor sheet prepared by mixing a powder with a powder is prepared, the precursor sheet is subjected to appropriate punching, and then a metal paste prepared by mixing a thermosetting resin and a metal powder is prepared. Print and apply in a predetermined pattern,
Finally, a precursor sheet on which the above-mentioned metal paste is applied by printing is laminated as needed, and this is applied to about 100-30.
It is manufactured by heat curing at a temperature of 0 ° C.

[0008]

However, a wiring board comprising an insulating substrate formed by bonding the inorganic insulating powder with a thermosetting resin and a wiring conductor formed by bonding a metal powder with the thermosetting resin is The thermosetting resin contained in the metal paste to be the wiring conductor has a low viscosity, so that the printability of the metal paste is poor, and a predetermined pattern is applied when the metal paste is applied by printing onto a precursor sheet to be an insulating substrate. However, it was difficult to accurately print and apply the wiring, and it was difficult to obtain a wiring board with fine wiring and high density.

If the content of the thermosetting resin contained in the metal paste serving as the wiring conductor is increased to more than about 30% by weight, the printability of the metal paste can be improved. Since the resistance increases, it is still impossible to obtain a wiring board with fine wiring and high density.

[0010]

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
And a semi-cured precursor sheet composed of the thermosetting resin of (1) and the inorganic insulating powders bonded by the thermosetting resin.
Then, a plurality of them were laminated and heat cured,
The edge powder is bonded by the thermosetting resin, and
Semi-hardened on the above-mentioned insulating substrate of the insulating base formed by stacking the edge substrates.
Said with the precursor sheet is thermally cured of reduction, Ri formed by the metal powder is deposited a wiring conductor coupled from <br/> thermosetting resin and thermoplastic resin and low-melting metal, the wiring conductor
The total amount of thermosetting resin and thermoplastic resin contained in
5 to 30% by weight based on the total amount of wiring conductors
The thermosetting resin contained in the wiring conductor and the thermoplastic
The blending amount of the thermoplastic resin with respect to the total amount of the resin is 5 to
And characterized in range der Rukoto of 90 wt%,
Insulating substrate even a portion is violently collide wiring board or between the wiring board and the semiconductor device fabrication automatic line since it is formed by bonding a thermosetting resin insulating substrate is excellent an inorganic insulating powder toughness There is no chipping, cracking, cracking or the like, and it is not necessary to contain a large amount of resin in the wiring conductor, so that the electric resistance of the wiring conductor can be made extremely small.

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 and an inorganic insulating powder, and a step of semi-curing the precursor sheet, the precursor sheet Netsukata of resin and thermoplastic resin and the metal powder and the low melting point metal powder mixed to made metal paste with printing in a predetermined pattern and <br/> step of semi-curing, the was semi-cured Semi-hard coated with metal paste
Which is characterized in that it consists of the precursor sheet a step of completely thermally cured <br/> the precursor sheet and the metal paste together with the laminating multiple sheets vertically, the reduction,
A precursor sheet made by mixing a thermosetting resin and an inorganic insulating powder, and a metal paste made by mixing a thermosetting resin, a thermoplastic resin, and a metal powder, which are produced by thermosetting, and a firing step There is no deformation and dimensional variation due to uneven firing shrinkage because there is no, and the metal paste printed and applied to the precursor sheet has an appropriate viscosity because it contains a thermoplastic resin. Can be accurately printed and applied when is applied to the precursor sheet.

[0012]

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 substrate and 2 is a wiring conductor.

The insulating substrate 1 comprises three insulating substrates 1a,
It is formed by stacking 1b and 1c, and has a recess 1d for accommodating a semiconductor element in the center of the upper surface, and the semiconductor element 3 is bonded to the bottom surface of the recess 1d via an adhesive such as resin. Fixed.

Insulating substrate 1a constituting the insulating substrate 1,
1b and 1c are, for example, silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate, strontium titanate, calcium titanate, titanium oxide,
It is formed by bonding inorganic insulating powder such as zeolite with thermosetting resin such as epoxy resin, polyimide resin, phenol resin, thermosetting polyphenylene ether resin, polyimide amide resin, bismaleimide triazine resin, etc. Since the three insulating substrates 1a, 1b, and 1c constituting 1 are each formed by bonding the inorganic insulating powder with a thermosetting resin such as an epoxy resin having excellent toughness, an external force is applied to the insulating substrate 1. Is applied, the insulating substrate 1 is chipped or cracked due to the external force,
No cracks will occur.

In addition, three insulating substrates 1 constituting an insulating substrate 1 formed by bonding the inorganic insulating powders with a thermosetting resin.
a, 1b, 1c, when the content of the inorganic insulating powder contained therein is less than 60% by weight, the coefficient of thermal expansion of the insulating substrate 1 greatly differs from the coefficient of thermal expansion of the semiconductor element 3,
The semiconductor element 3 emits heat during operation, and the heat is applied to the semiconductor element 3
When applied to both the insulating base 1 and the insulating base 1, a large thermal stress is generated between the two due to the difference in thermal expansion coefficient between the two, and the large thermal stress causes the semiconductor element 3 to peel from the insulating base 1, The element 3 is cracked or chipped. Therefore, the insulating substrate 1a that constitutes the insulating base 1,
1b and 1c are specified such that the amount of the inorganic insulating powder contained in each of them is in the range of 60 to 95% by weight.

[0016] The insulating substrate 1, for example, copper over the lower surface of its periphery recesses 1d, silver, wiring conductor a metal powder such as gold bound by a thermoplastic resin such as a thermosetting resin and an acrylic resin such as epoxy resin 2 is adhered and formed.

The wiring conductor 2 has a function of electrically connecting the electrodes of the semiconductor element 3 to an external electric circuit, and the electrodes of the semiconductor element 3 are provided at the portions located around the recess 1d of the insulating substrate 1. It is electrically connected via the bonding wire 4, and the portion led out to the lower surface of the insulating substrate 1 is electrically connected to an external electric circuit.

The metal powder contained in the wiring conductor 2 is
The wiring conductor 2 has the function of imparting conductivity to the wiring conductor 2.
Content is assumed that the electric resistance of the wiring conductor 2 higher is less than 70 wt% in, also firmly bonded to a predetermined wiring conductors 2 95% by weight is exceeded and the metal powder with a thermosetting resin and a thermoplastic resin Tend to be difficult to form. Therefore, it is preferable that the amount of the metal powder contained in the wiring conductor 2 is in the range of 70 to 95% by weight.

The thermosetting resin and the thermoplastic resin contained in the wiring conductor 2 serve to bind the metal powder contained in the wiring conductor 2 and to attach the wiring conductor 2 to the insulating substrate 1. and, in less than 5 wt% content of the wiring conductor 2, the metal powders with each other firmly bonded to the tend to be difficult to form the wiring conductors 2 and 30% by weight is exceeded and the wiring conductors 2 Has a tendency to have a large electric resistance. Therefore, the content of the thermosetting resin and the thermoplastic resin contained in the wiring conductor 2 is preferably in the range of 5 to 30% by weight.

Further, regarding the thermosetting resin and the thermoplastic resin contained in the wiring conductor 2, the thermosetting resin is the wiring conductor 2
The thermoplastic resin has a function of imparting good heat-resisting property to the metal paste which will be the wiring conductor 2 described later, and the thermoplastic resin with respect to the total amount of the thermosetting resin and the thermoplastic resin. is less than the amount of 5 wt%, it is assumed that the printing of the metal paste of the wiring conductor 2 is poor, print coating the metal paste insulating base plate 1a, 1b, a predetermined pattern on a precursor sheet of the 1c to it tends to be difficult to print accurately when, also the amount of the compounding obtain ultra 90% by weight, the wiring when the heat on the wiring board becomes as heat resistance of the wiring conductor 2 is low is applied Conductor 2
It is easy to cause deformation and disconnection. Therefore,
The thermosetting resin and the thermoplastic resin contained in the wiring conductor 2 preferably have a blending amount of the thermoplastic resin of 5 to 90% by weight with respect to the total amount of the thermosetting resin and the thermoplastic resin.

When the wiring conductor 2 is formed by depositing a metal having excellent corrosion resistance, such as nickel and gold, and having good conductivity 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, it is preferable that the exposed surface of the wiring conductor 2 is made of a metal having excellent corrosion resistance such as nickel or gold and having a good conductivity, which is 1.0 to 20.0 μm thick by plating.

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 1d of the insulating substrate 1 with an adhesive such as resin, and each electrode of the semiconductor element 3 is bonded with the bonding wire 4. It is electrically connected to the wiring conductor 2, and finally, the lid 5 is joined to the upper surface of the insulating base 1 through a sealing material made of resin or the like, and the semiconductor is placed inside the container made up of the insulating base 1 and the lid 5. A semiconductor device as a product is completed by hermetically housing the element 3.

Next, a method of manufacturing the wiring board used for the semiconductor element housing package will be described.

First, as shown in FIG. 2 (a), three precursor sheets 1 formed by bonding inorganic insulating powders with a thermosetting resin.
1a, 11b and 11c are prepared and heat is applied to these to semi-cure them.

The three precursor sheets 11a, 11b,
11c is formed by bonding inorganic insulating powder with a thermosetting resin, and has a particle size of 0.1 to 10 for example.
It is manufactured by forming a paste obtained by adding and mixing an epoxy resin and an imidazole-based curing agent to a silicon oxide powder of about 0 μm into a sheet by using a sheet forming method such as a doctor blade method.

The semi-cured precursor sheet 11 is used.
The hardness of a, 11b, and 11c is JIS7215,6.
When semi-cured to a hardness of 40 to 90 at a specified hardness for 301 type A measurement, the three precursor sheets 11a, 11b and 11c are punched or formed into wiring conductors 2 as described later. precursor sheet 11a in such when the made metal paste printing coating, 11b, exactly without causing deformation and cracks 11c, and can be reliably printing a stamping or metal paste so that the desired The wiring board can be manufactured accurately and surely. Therefore, the semi-cured precursor sheet 11
The hardness of a, 11b, and 11c is JISK7215,6.
It is preferable to set the hardness to the range of 40 to 90 with the specified hardness for 301 type A measurement.

Next, as shown in FIG. 2 (b), two of the three semi-cured precursor sheets 11a, 11b, 11c have openings A, A which become recesses 1d in the two precursor sheets 11a, 11b. Through holes B and B'for routing the wiring conductor 2 in the two precursor sheets 11b and 11c, respectively.

The openings A and A'and the through holes B and B'are
The precursor sheets 11a, 11b, and 11c are subjected to a conventionally known punching method to obtain the precursor sheets 11a, 11b, and 1
It is formed by boring a hole of a predetermined shape in each of 1c.

Next, as shown in FIG. 2 (c), a metal paste 12 to be the wiring conductor 2 is conventionally known in the upper and lower surfaces of the semi-cured precursor sheets 11b and 11c and in the through holes B and B '. A screen printing method and a filling method are used to print and apply a predetermined pattern, and this is heated at a temperature of about 25 to 100 ° C for 1 to 60 minutes to be semi-cured.

The metal paste 12 to be the wiring conductor 2 is, for example, a powder of copper having a particle size of about 0.1 to 20 μm and an epoxy resin such as bisphenol A type epoxy resin, novolac type epoxy resin, glycidyl ester type epoxy resin. And amine curing agents, imidazole curing agents,
A thermosetting resin such as a curing agent such as an acid anhydride-based curing agent and a thermoplastic resin such as an acrylic resin or a polyester resin are mixed together to form a paste.

Metal paste 12 which becomes the wiring conductor 2
Has a proper viscosity because it contains a thermoplastic resin, and when it is applied by printing in a predetermined pattern on the precursor sheets 11a, 11b, 11c to be the insulating substrates 1a, 1b, 1c, Can be applied by printing, so that a high-density wiring board with fine wiring can be manufactured.

The metal paste 1 to be the wiring conductor 2
2, when the content of the thermosetting resin and thermoplastic resin contained in this obtain super 30 wt%, the metal paste 12
When cured to form the wiring conductor 2, the electric resistance of the wiring conductor 2 becomes high, and if it is less than 5% by weight, fluidity as a paste cannot be sufficiently imparted to the metal paste 12. Insulating substrates 1a, 1 with metal paste 12
It tends to be difficult to accurately print and apply to the precursor sheets 11a, 11b, and 11c to be b and 1c. Therefore, the content of the thermosetting resin and the thermoplastic resin contained in the metal paste 12 is preferably in the range of 5 to 30% by weight.

Further, the metal paste 12 which becomes the wiring conductor 2 is a metal paste if the compounding amount of the thermoplastic resin is less than 5% by weight based on the total amount of the thermosetting resin and the thermoplastic resin contained therein. The viscosity of the paste 12 becomes small, and it tends to be difficult to accurately print and apply the metal paste 12 to the precursor sheets 11a, 11b, 11c to be the insulating substrates 1a, 1b, 1c.
Exceeding the wiring conductors 2 and curing the metal paste 12
Then, the heat resistance of the wiring conductor 2 becomes low,
When heat is applied to the wiring board, the wiring conductor 2 is likely to be broken or deformed. Therefore, the metal paste 12 contains the thermoplastic resin in an amount of 5 to 90 relative to the total amount of the thermosetting resin and the thermoplastic resin contained in the metal paste 12.
A weight% range is preferred.

Finally, the three semi-cured precursor sheets 11a, 11b and 11c are laminated on top of each other and heated at a temperature of about 80 to 300 ° C. for about 10 seconds to 24 hours, and the precursor sheets are stacked. Wiring in which the wiring conductor 2 is adhered to the insulating substrate 1 as shown in FIG. 1 by completely thermosetting the metal paste 12 printed and applied to the precursor sheets 11a, 11b and 11c and the precursor sheets 11b and 11c in a predetermined pattern. The board is completed. In this case, the precursor sheets 11a, 11b, 11c and the metal paste 12 hardly shrink during thermosetting, and therefore, the obtained wiring board is never deformed or the dimensions are varied. It is possible to accurately connect the element and the wiring conductor.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above-mentioned embodiments, Although the case where the wiring board of the invention is applied to a semiconductor element housing package that houses a semiconductor element has been described as an example, it may be applied to a wiring board used for other purposes such as a hybrid integrated circuit.

In the above embodiment, the wiring board is manufactured by stacking three precursor sheets, but one, two, or four or more precursor sheets are used. May be manufactured.

Further, in the above-mentioned embodiments, the insulating substrate is composed of the inorganic insulating powder and the thermosetting resin. However, in addition to these, glass fiber, carbon fiber, aramid fiber, alumina fiber, potassium titanate whisker is added. Short fibers such as aluminum borate whiskers may be mixed.

Furthermore, in the above-mentioned embodiment, the wiring conductor is
Although it was formed by bonding the metal powder with a thermosetting resin and a thermoplastic resin , it may be formed by further mixing a low melting point metal with the wiring conductor and bonding the metal powders with each other with the low melting point metal. well, in this case, the metal in the paste for forming the wiring conductor such as tin as the low melting point metal - after the Re this causes blended with low melting point metal powder made of lead solder was applied by printing the precursor sheet comprising an insulating substrate, which A method is adopted in which heat is applied to the low melting point metal to melt the low melting point metal powder, and the metal powder is bonded by the melted low melting point metal.

[0039]

According to the wiring board of the present invention, since the insulating substrate is formed by bonding the inorganic insulating powder with the thermosetting resin having excellent toughness, the wiring boards are connected with each other or the wiring board and the semiconductor device. Even if a part of the wiring conductor collides violently, the insulating substrate will not be chipped, cracked, or cracked, and since the wiring conductor contains a thermoplastic resin with excellent viscosity, a large amount of it will be contained in the wiring conductor. It is not necessary to include the resin of (1), and the electric resistance of the wiring conductor can be made extremely small.

According to the method of manufacturing a wiring board of the present invention, a precursor sheet obtained by mixing a thermosetting resin and an inorganic insulating powder, and a thermosetting resin, a thermoplastic resin, and a metal powder are mixed. Since the precursor sheet and the metal paste hardly shrink, the deformation and dimension variation due to the shrinkage do not occur, and the semiconductor element is accurately connected to the wiring conductor. You can connect to each other.

Further, according to the method for producing a wiring board of the present invention, since the metal paste printed and applied on the precursor sheet contains the thermoplastic resin, it has an appropriate viscosity, and this is printed and applied on the precursor sheet. It is possible to provide a wiring board with fine wiring and high density, which can be accurately applied by printing.

[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.

FIG. 2 is a cross-sectional view for each step for explaining the method for manufacturing a wiring board according to the present invention.

[Explanation of symbols]

1 ... Insulating substrate 2 ... Wiring conductor 11 ... Precursor sheet 12 ... Metal paste

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H05K 1/02 H05K 1/03 H05K 1/09 H05K 3/12 H05K 3/46 H01L 23/12-23 / 15 H01B 1/00-1/24

Claims (2)

(57) [Claims] 1. An inorganic insulating powder of 60 to 95% by weight and 5
To 40% by weight of a thermosetting resin, and a precursor obtained by binding the inorganic insulating powder with the thermosetting resin.
Sheets are semi-cured, multiple sheets are laminated and heat-cured
In addition, the inorganic insulating powder is bonded by the thermosetting resin.
The absolute insulating substrate formed by laminating a plurality of insulating substrates that
The edge substrate is heat cured with the semi-cured precursor sheet.
It was a metal powder with a thermosetting resin and a thermoplastic resin Sort
It is formed by attaching a wiring conductor bonded to the
The thermoplastic resin and thermosetting resin contained in the wiring conductor
The total amount with resin is 5 to 30 weight with respect to the total amount of wiring conductors.
% And the thermosetting property contained in the wiring conductor
Of thermoplastic resin to the total amount of resin and thermoplastic resin
Wiring board amount is characterized ranges der Rukoto of 5 to 90 wt%. 2. A thermosetting resin and an inorganic insulating powder are mixed together.
Preparing a precursor sheet comprising
Of semi-curing the resin and heat-curing the precursor sheet
Resin, thermoplastic resin, metal powder and low melting point metal powder are mixed
When the metal paste formed by combining is printed in a predetermined pattern
Semi-curing process and semi-cured metal paste
Top and bottom of the above-mentioned semi-cured precursor sheets
Laminating and stacking the precursor sheet and the metal pace
And a step of completely thermosetting the resin.
Method of manufacturing wiring board.