JP3301908B2 - 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 package for housing a semiconductor element for housing a semiconductor element or a hybrid integrated circuit board.

[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 the upper surface thereof. And a wiring conductor made of a refractory metal powder such as tungsten or molybdenum which is led out from the periphery to the lower surface of the concave portion of the insulating substrate, and a semiconductor element is formed on the bottom surface of the concave portion of the insulating substrate. Glass, resin, adhesively fixed via an adhesive such as a brazing material, and electrically connecting each electrode of the semiconductor element to a wiring conductor through an electrical connection means such as a bonding wire, and thereafter,
On the upper surface of the insulating substrate, a cover made of a metal, ceramics, or the like, so as to cover a concave portion of the insulating substrate, glass, resin,
A semiconductor device as a product is obtained by joining the semiconductor element in a concave portion of the insulating base in an airtight manner by joining through a sealing material such as a brazing material. The semiconductor element to be accommodated is electrically connected to the external electric circuit board by connecting to the wiring conductor of the board via an electrical connection means such as solder.

Incidentally, this conventional wiring board is generally manufactured by a ceramic green sheet laminating method, and specifically, an organic binder suitable for a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide and calcium oxide. , A solvent and the like are added and mixed to form a slurry, and this is formed into a sheet by employing a conventionally known doctor blade method to obtain a plurality of ceramic green sheets. After processing, a metal paste to be a wiring conductor is printed and applied in a predetermined pattern, and finally, the ceramic green sheets are stacked up and down in a predetermined order to form a green ceramic molded body. It is manufactured by firing at a high temperature of 1600 ° C.

[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. In addition, the semiconductor device cannot operate normally and stably for a long period of time.

According to the method of manufacturing a wiring board,
When firing the green ceramic molded body, unevenness in firing shrinkage occurs in the green ceramic molded body due to variations in the density of the ceramic raw material powder in each ceramic green sheet, and the resulting wiring board has deformation and dimensions such as warpage. As a result, it is difficult to electrically and accurately connect the semiconductor element and the wiring conductor, and if the deformation or the dimensional variation is large, the wiring conductor will be disconnected. Had disadvantages.

[0006]

According to the present invention, there is provided a wiring board comprising:
0 to 95% by weight of inorganic insulating powder and 5 to 40% by weight
Consisting of a thermosetting resin, wherein the inorganic insulating powder is
Precursor sheet composed of thermosetting resin precursor
Thereof a plurality are stacked and thermally cured by curing, plural linked by the thermosetting resin the inorganic insulator powder
The insulating substrate of the insulating substrate formed by laminating the insulating substrates of
Metal powder is tin - indium alloy, tin - bismuth alloy, tin
- it is characterized in that is applied at least wiring conductor made of a metal member and a thermosetting resin which is bonded with the bonding metal consisting of one zinc alloys.

Further, according to the method for producing a wiring board of the present invention, there is provided a step of preparing a precursor sheet comprising a mixture of a thermosetting resin precursor and an inorganic insulating powder, and heating the precursor sheet.
A step of semi-curing, the semi-cured precursor sheet,
Thermosetting resin precursor, metal powder and tin - indium alloy,
Tin - bismuth alloy, tin - a step of semi-curing by heating with printing a bonding metal powder and a mixture thereof comprising a metal paste comprising at least one zinc alloy in a predetermined pattern, a semi-cured the metal paste to be Dressed semi-cured
The precursor sheet was heated to this <br/> with stacked multiple sheets vertically, of the precursor sheet, and the metal paste together with the metal powder particles are bonded by the bonding metal to form a metal member by heat A step of thermally curing the curable resin precursor to integrate it.

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.

[0009] According to the wiring board of the present invention, the metal member of the wiring conductor is a metal powder of tin - by bonding the bonding metal consisting of at least one zinc alloy - indium alloy, tin - bismuth alloy, tin or that are formed
In addition, the electrical connection between the metal powders is ensured by the joining metal, and as a result, the electrical resistance of the wiring conductor can be reduced.

Further, according to the method for manufacturing a wiring board of the present invention,
In the wiring board includes the steps of preparing a precursor sheet formed by mixing a thermosetting resin precursor and the inorganic insulating powder, front
Heating the precursor sheet to semi-curing; and forming the semi-cured precursor sheet into a thermosetting resin precursor, a metal powder, a tin - indium alloy, a tin - bismuth alloy, and a tin - zinc alloy. heating with printing a metal paste formed by mixing a bonding metal powder consisting of at least one a predetermined pattern of
A step of semi-curing by a semi-cured the metal paste
A plurality of semi-cured precursor sheets to which is applied
This was heated with laminating, to integrate thermosetting resin precursor of the precursor sheet, and the metal paste with said metal powder particles are bonded by the bonding metal to form a metal member by thermally curing Since the precursor sheet and the thermosetting resin precursor of the metal paste hardly shrink at the time of thermosetting, there is no deformation or dimensional variation due to uneven shrinkage.

[0011] Incidentally, the tin is contained in the metal paste - indium alloy, tin - bismuth alloy, tin - bonding metal consisting of at least one zinc alloy whose melting point than the thermal decomposition temperature of the thermosetting resin Because of the low temperature of about 250 ° C., when the metal paste is heat-treated on the precursor sheet printed in a predetermined pattern to form a wiring board, the precursor sheet and the thermosetting resin of the metal paste do not undergo thermal decomposition. The metal powder can be reliably bonded by melting the bonding metal.

[0012]

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 package for housing a semiconductor element for housing a semiconductor element, wherein 1 is an insulating base, and 2 is a wiring conductor.

The insulating substrate 1 comprises three insulating substrates 1a, 1
The semiconductor element 3 is formed by laminating b and 1c, and has a concave portion 1d for accommodating 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 an inorganic insulating powder such as zeolite with a thermosetting resin such as an epoxy resin or a polyimide resin, and includes three insulating substrates 1a constituting the insulating base 1,
1b and 1c are each formed by bonding an inorganic insulating powder with a thermosetting resin having excellent toughness, so that even if an external force is applied to the insulating base 1, the insulating base 1 may be chipped by the external force. There are no cracks or cracks.

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. A large thermal stress is generated between the semiconductor element 3 and the semiconductor element 3 due to a difference in thermal expansion coefficient between the semiconductor element 3 and the large thermal stress, and the semiconductor element 3 is separated from the insulating base 1 or the semiconductor element 3 is cracked or chipped. . 95% by weight
Ultra El and the inorganic insulating powder can not be completely bound with a thermosetting resin, it becomes impossible to obtain a predetermined insulating substrate 1a, 1b, and 1c. Accordingly, the amount of the inorganic insulating powder contained in each of the insulating substrates 1a, 1b, and 1c constituting the insulating base 1 is specified in the range of 60% by weight to 95% by weight.

A wiring conductor 2 is formed on the insulating substrate 1 from the periphery of the concave portion 1d to the lower surface. The wiring conductor 2 is made of a metal powder such as copper or silver by using a tin - indium alloy or a tin - bismuth alloy. , A metal member joined with a joining metal made of at least one of tin - zinc alloy and a thermosetting resin such as an epoxy resin or a polyimide resin, and the metal member is formed on the insulating base 1 with the thermosetting resin. By being attached, it is integrally attached to the insulating base 1.

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

Furthermore, the wiring conductor 2 is a metal member constituting the copper, the metal powder such as silver-tin - indium alloy, tin
- bismuth alloy, tin - zinc alloy of at least between the metal powder because it is formed are bonded by the bonding metal consisting of one electrical connection and a low-resistance reliable and makes electrical resistance of the wiring conductor 2 by bonding metal Nasukoto Can be.

When the total weight of the metal powder and the joining metal is less than 70% by weight with respect to the total weight of the wiring conductor 2, the wiring conductor 2 made of the metal powder, the joining metal and the thermosetting resin is less than the metal powder. with wiring conductors bonded via the bonding metal is tend to be incomplete, the addition wiring conductors 2 of 95% by weight is exceeded and the thermosetting resin becomes difficult to firmly adhered to the insulating base 1 2 tends to be brittle. Therefore, it is preferable that the total weight of the metal powder and the bonding metal 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.

When the amount of the metal powder and the joining metal contained in the wiring conductor 2 is less than 20% by weight based on the total weight of the metal powder and the joining metal, the amount of the joining metal is large relative to the metal powder. In this case, the joining metals are fused with each other to make it difficult to integrate the metal powders, and the electrical resistance of the wiring conductor 2 tends to increase.
The amount of bonding metal that joins is exceeded and the metal powder becomes relatively small, there is a tendency that the electric resistance of the wiring conductor 2 can not be satisfactorily bonded to the metal powder is increased. Accordingly, the metal powder contained in the wiring conductor 2 is 20% by weight to 8% by weight based on the total weight of the metal powder and the joining metal.
It is preferable to set the range to 0% by weight.

The metal powder contained further to the wiring conductor 2 and tin - indium alloy, tin - bismuth alloy, tin - bonding metal consisting of at least one zinc alloy metal when the average particle diameter is less than 0.1μm powder and bonding metal are agglomerated uniform dispersion can not be obtained, also commonly require Exceeding the width of the wiring conductor 2 50 [mu] m 50Myuemu～20
It becomes difficult to print and form in the range of 0 μm. Therefore,
The metal powder and bonding metal contained in the wiring conductor 2 and the average particle diameter you to a range of 0.1μm to 50μm preferred.

Thus, according to the above-described wiring board, the semiconductor element 3 is bonded and fixed to the bottom surface of the concave portion 1 d of the insulating base 1, and each electrode of the semiconductor element 3 is electrically connected to the wiring conductor 2 via the bonding wire 4. Finally, a lid 5 is bonded to the upper surface of the insulating base 1 via a sealing material, and the semiconductor element 3 is hermetically accommodated in a container including the insulating base 1 and the lid 5 to thereby provide a semiconductor product. Device.

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 an epoxy resin made of an inorganic insulating powder such as silicon oxide, aluminum oxide, aluminum nitride, silicon carbide, barium titanate, strontium titanate, and titanium oxide;
It is formed by bonding with a thermosetting resin precursor such as a polyimide resin and a polyphenylene ether resin. For example, a silicon oxide powder having a particle size of 0.1 to 100 μm is added to a bisphenol A type epoxy resin or a novolak type epoxy resin. , Epoxy resins such as glycidyl ester type epoxy resins and amine-based curing agents, imidazole-based curing agents,
A curing agent such as an acid anhydride curing agent is added and mixed to form a paste, and then 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. Produced by

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

As the metal paste 12, for example,
Grain size in the metal powder of copper powder and silver powder or the like of about 0.1Myuemu～20myuemu, particle size of about 1μm~50μm tin -
Indium alloy, tin - bismuth alloy, tin - and bonding metal powder consisting of at least one zinc alloy, Bisufe Roh Lumpur <br/> A type epoxy resin, novolak type epoxy resins, epoxy resins such as glycidyl ester type epoxy resin A paste obtained by adding and mixing a curing agent such as an amine curing agent, an imidazole curing agent, and an acid anhydride curing agent is used.

Finally, the three precursor sheets 11
a, 11b, and 11c are vertically stacked and heated at a temperature of about 300 ° C. for 10 seconds to 24 hours to melt the bonding metal in the metal paste 12 and bond the metal powders with the molten bonding metal. In this way, the thermosetting resin precursors of the precursor sheets 11a, 11b, 11c and the metal paste 12 are completely thermoset and integrated, thereby forming the wiring conductor 2 on the insulating base 1 as shown in FIG. The wiring board used for the package for housing the semiconductor element to which is adhered is completed. In this case, the precursor sheets 11a, 11b, and 11c hardly shrink at the time of thermosetting, so that the resulting wiring board is effectively prevented from being deformed or having a variation in dimension, and disconnection of the wiring conductor 2 is prevented. Without inviting, it is possible to reliably electrically connect the electrodes of the semiconductor element 3 and the like to the external electric circuit via the wiring conductor 2.

The bonding metal of the metal paste 12 comprising at least one of a tin - indium alloy, a tin - bismuth alloy and a tin - zinc alloy has a melting point of the precursor sheet 11.
Since the temperature is about 250 ° C. lower than the temperature at which the thermosetting resin contained in the a, 11b, 11c and the metal paste 12 is thermally decomposed, the precursor sheets 11a, 11b, on which the metal paste 12 is printed in a predetermined pattern, When heat-treating 11c to form a wiring board, precursor sheets 11a, 11b, 1
The joining metal can be melted without causing thermal decomposition of the thermosetting resin of the metal paste 1c and the metal paste 12, and the metal powder can be reliably joined together by the melted joining metal.

It should be noted that the present invention is not limited to the above-described embodiment, and is within the scope of the present invention.
Various modifications are possible. For example, in the above-described 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, but this is applied to a hybrid integrated circuit board or the like. The present invention may be applied to a used wiring board.

In the above embodiment, the wiring substrate is formed by laminating three insulating substrates. However, the wiring substrate may be formed by laminating one, two, or four or more insulating substrates. Good.

Further, in the above embodiment, the metal paste 1
2) A thermosetting resin such as an epoxy resin used in (2) contains a conductive resin such as a polyacetylene resin or a polyphenylene resin, or a thermosetting resin such as a conductive polypyrrole resin, a polyparaphenylene resin, or a polyaniline resin. When an electrically conductive resin is used as an alternative, the precursor sheet 1 on which the metal paste 12 is printed in a predetermined pattern is used.
When heat-treating 1a, 11b, and 11c to form a wiring board, even if there is a partial imperfection in the joining between the metal powders by the joining metal, the imperfect part is due to electrical connection by a conductive resin. As a result, the electrical connection between the metal powders becomes more reliable, and the electrical resistance of the wiring conductor 2 can be made lower.

Further, the metal paste 12 is formed by adding and mixing a metal powder and a bonding metal powder to a thermosetting resin precursor. It may be formed by adding to the precursor. In this case, the formation of the metal paste 12 is extremely easy since only one type of metal powder having a bonding metal adhered to its surface is added instead of adding two types of metal powder to the thermosetting resin precursor. prebonded metal on the surface of the metal powder with ing to the time of forming the wiring conductor 2 by heating process because it is deposited, the bonding between the metal powder through a bonding metal becomes more reliable. Therefore, the bonding metal is adhered to the surface of the thermosetting resin precursor rather than the metal paste 12 formed by adding and mixing two kinds of powders of the metal powder and the bonding metal powder to the thermosetting resin precursor. It is desirable to form by adding one kind of metal powder.

[0037]

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.

Further, according to the wiring board of the present invention, the metal member of the wiring conductor 2 is a metal powder tin - indium alloy, tin -
Whether it is formed by joining with a joining metal consisting of at least one of a bismuth alloy and a tin - zinc alloy
Accordingly, the electrical connection between the metal powders is ensured by the joining metal, and as a result, the electrical resistance of the wiring conductor 2 can be reduced.

Further, according to the method for manufacturing a wiring board of the present invention,
In the wiring board includes the steps of preparing a precursor sheet formed by mixing a thermosetting resin precursor and the inorganic insulating powder, front
Heating the precursor sheet to semi-curing; and forming the semi-cured precursor sheet into a thermosetting resin precursor, a metal powder, a tin - indium alloy, a tin - bismuth alloy, and a tin - zinc alloy. heating with printing a metal paste formed by mixing a bonding metal powder consisting of at least one a predetermined pattern of
A step of semi-curing by a semi-cured the metal paste
A plurality of semi-cured precursor sheets to which is applied
This was heated with laminating, to integrate thermosetting resin precursor of the precursor sheet, and the metal paste with said metal powder particles are bonded by the bonding metal to form a metal member by thermally curing Since the precursor sheet and the thermosetting resin precursor of the metal paste hardly shrink at the time of thermosetting, there is no deformation or dimensional variation due to uneven shrinkage.

The joining metal of the tin - indium alloy, tin - bismuth alloy, and tin - zinc alloy contained in the metal paste has a melting point lower than the temperature at which the thermosetting resin thermally decomposes. Because of the low temperature of about 250 ° C., when the metal paste is heat-treated on the precursor sheet printed in a predetermined pattern to form a wiring board, the precursor sheet and the thermosetting resin of the metal paste do not undergo thermal decomposition. By melting the bonding alloy, the metal powders can be reliably bonded to each other.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment in which a wiring board of the present invention is applied to a package for housing a semiconductor element.

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]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 1a, 1b, 1c ... Insulating substrate 2 ... Wiring conductor 11a, 11b, 11c ... Precursor Body sheet 12 Metal paste

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 1 / 02,1 / 03,1 / 09 H05K 3 / 12,3 / 46 H01L 23/12-23 / 15 H01B 1/00-1/24

Claims (2)

(57) [Claims] An inorganic insulating powder of 60 to 95% by weight and 5
Or consists of a 40 wt% of a thermosetting resin, wherein the inorganic insulation
Before bonding the edge powder with the thermosetting resin precursor
Semi-cured precursor sheets, laminating multiple sheets and heat curing
In front of an insulating substrate formed by laminating a plurality of insulating substrates obtained by bonding the inorganic insulating powder with the thermosetting resin.
The serial insulating substrate, the metal powder of tin - indium alloy, tin - bismuth alloy, tin - is applied to the wiring conductor made of a metallic member is joined by bonding metal consisting of at least one thermosetting resin of the zinc alloy A wiring board, comprising: 2. A process for preparing a precursor sheet formed by mixing a thermosetting resin precursor and the inorganic insulating powder, said precursor
A step of semi-cured by heating the sheet, the precursor sheet was semi-cured, the thermosetting resin precursor and a metal powder and tin -
Indium alloy, tin - bismuth alloy, tin - zinc alloy is mixed with a joining metal powder composed of at least one kind, and a metal paste is printed in a predetermined pattern and heated.
A semi-curing step, and applying the semi-cured metal paste
A plurality of the semi-cured precursor sheets attached are laminated one above the other.
Heat treatment so as to, prior to the metal powder particles
Step of integrating the thermosetting resin precursor of the precursor sheet, and the metal paste is thermally cured with serial are joined by bonding metal to form a metal member, be composed of capital
A method for manufacturing a wiring board, comprising: