JP3273113B2 - Multilayer wiring board - 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 in which a semiconductor device is housed and mounted, and a hybrid integrated circuit device in which various electronic components such as capacitors and resistors are mounted in addition to the semiconductor device. The present invention relates to a ceramic multilayer wiring board to be used.

[0002]

2. Description of the Related Art Conventionally, a ceramic multilayer wiring board used for a package for accommodating a semiconductor element, a hybrid integrated circuit device, or the like generally uses a slurry obtained by adding an organic binder to a ceramic powder containing alumina as a main component and kneading it. An insulating substrate made of an alumina sintered body formed by laminating a plurality of ceramic green sheets after forming them into a sheet by a doctor blade method or the like is used.

A metallized metal layer made of a refractory metal such as tungsten (W) or molybdenum (Mo) is provided on the surface or inside of the insulating base as a wiring conductor, and the wiring conductor of each layer is insulated. They are connected to each other by through-hole conductors made of the same high-melting point metal provided in the base.

When the multilayer wiring board is applied to, for example, a package for accommodating a semiconductor element, the 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. Each electrode of the element is electrically connected to a wiring conductor located around the concave portion via a bonding wire, and a cover made of metal, ceramics, or the like is interposed via a sealing material similar to the adhesive so as to cover the concave portion. And a semiconductor device as a final product by hermetically housing the semiconductor element in a concave portion of the insulating base.

[0005] In recent years, ICs with higher frequencies and higher densities have progressed.
A multi-layer wiring board on which a semiconductor element such as an LSI or the like is mounted. In order to increase the speed and radiate heat of the semiconductor element and to mount the semiconductor element compactly, for example, a surface electrode of the semiconductor element is used as a wiring electrode of the multilayer wiring board. A flip chip connection method of directly connecting with solder bumps or the like has been adopted.

In the flip-chip connection method, a high flatness is required because the surface electrode of the semiconductor element is directly connected to the wiring electrode of the multilayer wiring board as described above.
In order to ensure the flatness, various methods have been taken such as making the density of the laminate and the temperature distribution during firing uniform.

However, the coefficient of thermal expansion between the electrically insulating alumina-based sintered body and the metallized metal layer is, for example, about 7.5 × 10 5 in a temperature range from room temperature to 500 ° C.
⁻⁶ / ° C. and about 4.5 to 5.4 × 10 ⁻⁶ / ° C., the simultaneous firing causes warpage or undulation in the multilayer wiring board due to a difference in shrinkage in the firing process. Deformation exceeding 1.04 μm / mm per unit length occurred, and it was difficult to obtain a high-quality wiring board with good flatness and good yield.

In order to solve the above problem, a straightening method using a jig, a preliminary sintering in a temperature range higher than the softening temperature of the inorganic material and lower than the firing temperature of the ceramic substrate as the insulating base, There has been proposed a method of performing main firing under a load (see Japanese Patent Publication No. 2-25277 and Japanese Patent Laid-Open Publication No. 4-31368).

[0009]

However, in the above-mentioned proposal, although the deformation such as warpage or undulation of the multilayer wiring board is reduced, a plurality of firing steps of pre-sintering and further firing are required. There was a problem that the cost was significantly increased.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to reduce the manufacturing cost and to effectively prevent deformation such as warpage or undulation without requiring a plurality of firing steps. An object of the present invention is to provide a multilayer wiring board having a good degree.

[0011]

A multilayer wiring board according to the present invention comprises a wiring pattern of a metallized metal layer formed on the surface or inside of an insulating base made of a laminate of alumina-based sintered bodies. A metallized metal layer formed at least immediately below the surface layer of the multilayer wiring board, that is, a wiring conductor layer made of glass and a refractory metal made of at least one of tungsten (W) and molybdenum (Mo) has a thickness of the wiring conductor layer. Silica (SiO 2)
₂ ), the maximum content of the distribution shown by calcia (CaO) and magnesia (MgO) is 30 with respect to the thickness of the wiring conductor layer.
And the maximum content is in the range of 6.62 to 7.58 with respect to 100 parts by weight of the refractory metal, respectively.
Parts by weight, 1.23 to 1.40 parts by weight, 0.95 to 1.0
8 parts by weight.

In the multilayer wiring board of the present invention, the glass component silica (Si) is used in a cross section of the wiring conductor layer in the thickness direction.
O ₂ ) and calcia (CaO), magnesia (MgO)
Is outside the range of 30 to 70% with respect to the thickness of the wiring conductor layer, and the value is 6.62 to 7.58 with respect to 100 parts by weight of the refractory metal, respectively. Parts by weight, 1.23 to 1.40 parts by weight, 0.95 to 1.08
When the content is out of the range of parts by weight, that is, when the position of the maximum content value is less than 30% or the value is less than the lower limit value of each glass component, the firing of the metallized metal layer forming the wiring conductor layer is performed. If the maximum content exceeds 70%, or if the value exceeds the upper limit of each glass component, excessive sintering of the metallized metal layer causes the refractory metal itself to become insufficient. Grain growth also occurs, and firing shrinkage of the metallized metal layer becomes large, causing problems such as warpage of the multilayer wiring board.

Accordingly, the position indicated by each maximum content value of the glass component is limited to 30 to 70% with respect to the thickness of the wiring conductor layer, and the maximum content value is defined with respect to 100 parts by weight of the high melting point metal. 6.62 to 7.58 parts by weight, 1.2 respectively
It is specified in the range of 3 to 1.40 parts by weight and 0.95 to 1.08 parts by weight.

Further, the stress caused by the difference in thermal expansion between the insulating base and the metallized metal layer forming the wiring conductor layer is absorbed by the metallized metal layer because cracks may be generated inside the multilayer wiring board. The metallized metal layer desirably has high rigidity such as Young's modulus in that the stress concentrated on the insulating base is more effectively reduced.

The metallized metal layer may be any one or more of high melting point metals such as tungsten (W) and molybdenum (Mo). The metallized metal layer is formed so as to be porous after sintering. Accordingly, the effect of reducing the stress concentration can be further increased.

[0016]

The multilayer wiring board of the present invention is a multilayer wiring board having a wiring pattern of a metallized metal layer on the surface or inside of an insulating substrate made of an alumina sintered body, and formed at least immediately below the surface layer of the multilayer wiring board. In a cross section in the thickness direction of a wiring conductor layer made of glass and a high melting point metal made of at least one of tungsten (W) and molybdenum (Mo), silica (SiO ₂ ), calcia (CaO), and magnesia (MgO ) Is 30 to 70 with respect to the thickness of the wiring conductor layer.
% And the maximum content of the glass component is 6.62 with respect to 100 parts by weight of the high melting point metal.
-7.58 parts by weight, 1.23-1.40 parts by weight, 0.9
Since the content is within the range of 5 to 1.08 parts by weight, the matching of shrinkage between the metallized layer and the alumina-based sintered body is improved, and deformation such as warpage or undulation of the multilayer wiring board due to a difference in shrinkage in the firing process is achieved. As a result, the stress generated due to the difference in thermal expansion is reduced, and as a result, the metallized metal layer can be firmly attached to the insulating base.

[0017]

Next, a multilayer wiring board of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment in which the multilayer wiring board of the present invention is applied to a semiconductor element housing package in which semiconductor elements are housed and mounted by a flip-chip connection method, and FIG. It is principal part sectional drawing which shows the state which mounted the semiconductor element in the element storage package.

1 and 2, reference numeral 1 denotes a multilayer wiring board in which a wiring conductor layer 3 made of a metallized metal layer is integrally formed in an insulating base 2, and each of the wiring conductor layers 3 penetrates through the insulating base 6. Are connected to each other by through-hole conductors 4 provided.

In the package for mounting a semiconductor element shown in FIG. 2 with the semiconductor element mounted thereon, the surface electrode of the semiconductor element 5 is provided at the center of the upper surface of the insulating base 2 by a through-hole conductor 4.
1 is directly connected to the wiring electrode 8 shown in FIG.
Through the through-hole conductor 4 for connecting to the lower surface.

Further, an external lead terminal 7 connected to an external electric circuit is electrically connected to a portion led out to the lower surface of the insulating base 2, and each electrode of the semiconductor element 5 is electrically connected to the external lead terminal 7. Finally, a lid (not shown) made of metal, ceramics, or the like is joined to the upper portion of the semiconductor element 5 via a sealing material, so that the semiconductor element 5 is electrically connected to the insulating base 2. It is mounted air-tight at the center of the upper surface of the.

In the multilayer wiring board of the present invention, at least the wiring conductor layer 3 immediately below the surface layer formed of a metalized metal layer made of glass and a refractory metal made of at least one of tungsten (W) and molybdenum (Mo) is used. The position of the maximum content value of the glass component appearing in the cross section in the thickness direction is within a range of 30 to 70% with respect to the thickness of the wiring conductor layer 3, and the maximum content value of each of the glass components is higher than the high content. 6.62 to 7.58 parts by weight based on 100 parts by weight of the melting point metal;
1.23 to 1.40 parts by weight, 0.95 to 1.08 parts by weight.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In evaluating the wiring board of the present invention, first,
As alumina formed body, Al ₂ O ₃ 90~96 wt%
On the other hand, a known organic binder was added to each raw material powder obtained by adding and mixing 4 to 10% by weight of SiO ₂ , MgO, CaO and the like.
A slurry was prepared by adding and mixing a plasticizer and a solvent, and the slurry was formed into a ceramic green sheet for an insulating substrate having a thickness of about 500 μm by a well-known tape forming technique such as a doctor blade method or a calendar roll method.

Next, W, Mo having a particle diameter of 1 to 5 μm, and tungsten (W) -molybdenum (Mo) having a content of 20% by weight and 30% by weight of molybdenum metal having a melting point of 97% were used.
9% by weight, Al ₂ O ₃ to 2.0% by weight, Nb ₂ O ₅ to 0.1% by weight, kneading and kneading an organic solvent such as a binder and a surfactant and a solvent, and kneading the mixture. A paste sample was obtained.

After the paste sample for a metallized metal layer thus obtained is printed on the entire outer surface of one of the ceramic green sheets by a screen printing method, the ceramic green sheet is cut into a square having a length of 70 mm and a width of 70 mm. In a reducing atmosphere consisting of nitrogen and hydrogen,
The sample was fired in a temperature range of 1480 to 1600 ° C., and an evaluation sample in which a metallized metal layer having a thickness of about 20 μm was formed on the surface of an insulating substrate made of an alumina sintered body was prepared.

[0025]

[Table 1]

First, using the evaluation sample, the surface of the metallized metal layer of the evaluation sample is diagonally contacted with a contact-type surface roughness meter equipped with a diamond needle, and the warped shape is measured. The warpage was calculated and the maximum value was calculated.

Next, the evaluation sample after the measurement of the warped shape is cut, and the cross section thereof is polished at an angle. Then, the polished surface of the metallized metal layer is divided into 10 equal parts, and EPMA is applied at each position. The contents of SiO ₂ , CaO, and MgO were quantitatively analyzed and the distribution was measured.

As a reference substance for the EPMA analysis, the alumina composition, pure W and pure Mo of the evaluation sample were used.

Further, the surface of the metallized metal layer of the sample for evaluation was coated with nickel (Ni), and an iron-nickel lead pin was bonded thereon with a silver solder, and then the lead pin was pulled at a tensile speed of 10 mm / min. The load at the time of pulling and peeling was evaluated as metallized strength.

On the other hand, the bulk density was measured using an alumina-based sintered body corresponding to an insulating substrate fired in the same manner as described above without forming the metallized metal layer.

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

As is clear from the table, SiO ₂ , Ca
Sample No. 1 in which the maximum content of O and MgO is less than 30% or more than 70% with respect to the thickness of the wiring conductor layer, or the maximum content is outside the scope of the claims of the present application.
4, 5, 10, 11, 13, 14, and 17 have a maximum warpage of 1.04 μm / mm or more, whereas the samples of the present invention have a warpage of 1.03 μm / mm or less. .

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention.

[0037]

According to the multilayer wiring board of the present invention, the wiring conductor layer formed of the metallized metal layer formed on the multilayer wiring board is made of silica (SiO ₂ ), The maximum content value of the distribution represented by calcia (CaO) and magnesia (MgO) is in the range of 30 to 70% with respect to the thickness of the wiring conductor layer, and the maximum content value of each of the distributions in the metalized metal layer is High melting point metal 10
6.62 to 7.58 parts by weight, 1.23 parts by weight with respect to 0 parts by weight
Since it is within a range of from 1.40 parts by weight and 0.95 to 1.08 parts by weight, deformation such as warpage or undulation can be effectively prevented at a low cost by one firing, and good flatness can be obtained. A multilayer wiring board can be obtained.

Further, even if a thermal stress is generated between the metallized metal layer and the insulating substrate during firing due to the difference in the thermal expansion coefficient between the metalized metal layer and the insulating substrate, the thermal stress hardly remains in the multilayer wiring board. As a result, even if an external force or a thermal shock force is applied to the wiring board, no crack is generated in the insulating base, and it is possible to effectively prevent the wiring conductor from being disconnected or the like. It can be firmly attached to the vehicle.

As a result, the speeding up and heat dissipation of the semiconductor element can be effectively realized, and the semiconductor element can be mounted compactly, such as various control equipment and information communication equipment which are required to be mounted at high density. It is extremely useful for the use of

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment in which a multilayer wiring board of the present invention is applied to a semiconductor element housing package in which semiconductor elements are housed and mounted by a flip chip connection method.

FIG. 2 is a cross-sectional view illustrating a state where a semiconductor element is mounted on the semiconductor element storage package of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 multilayer wiring board 2 insulating base 3 wiring conductor layer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-122681 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/46 H01L 23/12

Claims (1)

(57) [Claims] 1. A multilayer wiring board having a wiring conductor layer made of glass and at least one of tungsten (W) and molybdenum (Mo), which are refractory metals, formed on the surface or inside of an insulating substrate made of an alumina sintered body. And a glass component of silica (SiO ₂ ), calcia (CaO), and magnesia (Mg) in a cross section in the thickness direction of the wiring conductor layer.
O) distribution is 30 to 70% with respect to the thickness of the wiring conductor layer.
In the range of 6.62 to 7.58 parts by weight, 1.23 to 1.40 parts by weight and 0.95 to 1.40 parts by weight, respectively, based on 100 parts by weight of the high melting point metal. A multilayer wiring board characterized by being in the range of 08 parts by weight.