JPS6112091A - Multilayer circuit board and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a multilayer circuit board and a method for manufacturing the same. In particular, the present invention relates to a multilayer circuit board using a glass-ceramic insulating material and a method for manufacturing the same. 'This type of multilayer circuit board is used, for example, as a highly integrated circuit board on which a large number of LSI chips are mounted.

[Background of the invention]

Conventionally, the substrate on which an LSI chip is mounted is made by printing a conductor of a high-melting point metal such as tungsten on a raw material sheet mainly made of alumina, or a so-called green sheet, using thick film technology, and then laminating these sheets to form a multilayer green sheet. It is manufactured as a sheet by sintering this in a high temperature non-oxidizing atmosphere at about 1500°C.

However, such alumina-based multilayer wiring boards have a problem in that they are not sufficient to meet the demands for high-speed arithmetic processing, which has been desired in recent years, particularly in the field of information processing devices. Alumina has a relatively high relative dielectric constant, and fine-wiring tungsten conductors have high wiring resistance, so the signal delay time propagating through the wiring within the multilayer layer is difficult to meet the ever-increasing demands for faster calculation processing. be. For this reason, metal wiring with low electrical resistance and insulating materials with low dielectric constant are required.

Against the background of the above circumstances, highly conductive metals, namely Ag.

It has been proposed to use glass and crystallized glass as insulating materials for multilayer substrates so that materials with melting points around 1000°C, such as Au-, Cu, and Ag/Pa, can be used for wiring. (No. 127112, 1973). In addition, in Japanese Patent Application Laid-Open No. 54-111517,
α-1-Sierra, Ito (MgOIIA1203・S i
02 ) and β-sinomen (Li2O・Al2Os
A crystallized glass ceramic whose main crystal is 5in) has been disclosed. These technologies are certainly considered to be more advantageous than conventional alumina-based multilayer substrates. For example α−
1-gelite and β-spodumene have thermal expansion coefficients in the range of +50 x 10"7°C, and are suitable for Si chips (L).
SI) o It is possible to almost match the coefficient of thermal expansion (approximately 30 x 10-77°C), and it is possible to suppress stress fracture due to temperature cycling of the connection portion due to the difference in thermal expansion. In addition, these substrates have high bending strength, 1500 ky
/cy1 or more, which is more than double the bending strength of general glass, making it possible to suppress peeling damage from the substrate of the input/output bin connected to the 5LSI chip and the substrate.

However, when considering the above-mentioned speed-up of arithmetic processing, the dielectric constant of glass ceramics is still high, and therefore the signal delay time propagating through multilayer wiring still cannot sufficiently meet the demand. Ideally, it would be desirable to have a dielectric constant of 5 or less, or to keep Fi around 5 to 6, but at present this requirement is not met. In addition, its coefficient of thermal expansion is less than X 10-7/'C, υ, 140
X 10'/℃ or more" e Ag + Cu,
There is a problem in that wiring conductors such as Ag/Pa and terminals on the surface layer are likely to peel off. Therefore, even if a general Si chip is used as an LSI, its coefficient of thermal expansion is approximately 30X.
10-7/"C and 9% difference, stress failure does not occur in the connection part even with temperature cycles, and 140 x 10-
An advantageous glass-ceramic insulating material is desired, which has a coefficient of thermal expansion of 7/'C or more, is similar to the above-mentioned highly conductive metals, and is less likely to cause terminal peeling.

[Purpose of the invention]

The purpose of the present invention is to use a glass-ceramic insulating material with an extremely low dielectric constant, so that the delay speed of signal propagation is extremely small, which is sufficient for high-speed processing, and which has high bending properties, high strength, and an appropriate coefficient of thermal expansion. An object of the present invention is to provide an advantageous multilayer circuit board that can be selected within a wide range of options, and a method for manufacturing the same.

[Summary of the invention]

In order to achieve this objective, the multilayer circuit board of the present invention includes:
66-79 wt% Si02, 9-20 wt% Li2O
wt%, Ad203 at 3-10 wt%, K2O at 1
~3wt% and 3wt Tj 04 or P2O5
A circuit is multilayered using a material obtained by mixing 70 to 40 wt% of a glass material containing 70 to 40 wt% of silica glass and 60 wt% of silica glass as a glass-ceramic insulating material.

This glass-ceramic material has a low dielectric constant, high refraction, and a coefficient of thermal expansion within an appropriate range, and thus satisfies the above objectives.

Another invention of the present application is to use such a mixture material in a range of 750 to 8
It is heat-treated at a temperature of 50° C. and used as a glass-ceramic insulating material. -゛Quartz glass has an extremely low dielectric constant (approximately 4) and a low coefficient of thermal expansion (approximately 5
10"/"C), so by mixing the above-mentioned glass and silica glass with this structure, the dielectric constant can be lowered, and thereby the coefficient of thermal expansion can be adjusted to a desired value. I can do it.

Still another invention of the present application is a method for manufacturing a multilayer wiring board as described above, in which a mixture of the glassy material and quartz glass is heat-treated at a crystal precipitation temperature of 750 to 850°C, and lithium silicate (Li2O. In this method, 2S102) is precipitated to form crystallized glass, and this is used as a glass-ceramic insulating material to form a multilayer circuit to obtain a multilayer circuit board. According to this method, since the heating temperature is lower than the melting point of the highly conductive metal, it is advantageous as a method for manufacturing a multilayer circuit board that speeds up signal propagation.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The multilayer wiring board obtained in this example has a structure as shown in the cross-sectional view in the attached drawing, and as shown in the figure, desired wiring 2 is formed on an insulating material l made of glass ceramic. The circuit is multilayered, and this wiring 2 is connected to the bin 5 via the bin connection terminal 3, and the LSI
By being connected to the LSI 6 via the connection terminal 4,
It is equipped with LSI6. The glass-ceramic insulating material obtained in this example is embodied, for example, as a multilayer wiring board having such a structure.

The glass-ceramic insulating material of this example is S 10
2, Li2O, Alz03, KlIO3, and P2O5-straddling Ti02 as components and the composition was formed as listed in 51 to A7 in Table 1, and vitreous material was mixed with silica glass. use something In this example, such a glassy material is used at 750~
It is heat-treated at a temperature of 850° C. and used as a glass-ceramic insulating material, and in this case, in this heat treatment, lithium silicate (Ls, 0.2SiO2) is precipitated as a main crystal and used as crystallized glass.

The multilayer wiring board of this example is manufactured according to the steps I to (2) described below.

Step I: Preparation of Nigarasu powder 5IO2, Li2O so as to have the composition shown in Table 1.

'-13203r K29 + P2O5 (or Ti
02) as an oxide or carbonate, and after mixing,
It is put into a platinum crucible and melted at 1400°C. This is rapidly cooled and pulverized to create a glass powder with an average particle size of 1.5 μm.

Process ■: Creation of green sheet Here, a predetermined amount of quartz glass with an average particle size of 1.0 μm (
30-60W t%) is added to the above glass powder and mixed,
Polyvinyl butyral resin is added and further mixed, a plasticizer/volatile solvent is added, crosstalk is performed, and a slip is created by degassing. The blending ratio of the vitreous (crystallized glass) powder and quartz glass is as shown in Table 2, and the composition of the vitreous material used on each side of flats 1 to A8 in this example is as follows:
It was identified by the storms listed in Table 1.

Next, this slip is applied onto a film of 2-reester or the like by a doctor blade method and dried to create a glass green sheet, and conductive holes necessary for the circuit and reference holes for positioning the printing layer are formed in this green sheet.

Step (2): Printing and laminating a conductive paste and sheet A conductive paste was prepared by adding a vehicle in which ethyl cellulose and polyvinyl butyral resin were melted to the gold powder. This is printed and filled into holes formed in the sheet, and necessary wiring circuits are formed.

Also, the terminal to which the LSI and input/output bin are connected is A
It is formed by block printing of g/Pd.

Green sheets with predetermined circuits and tongues printed on them are stacked one on top of the other, cut into a predetermined shape, and then pressurized and heated (12
0° C.) to create a laminate.

Step (2): The sintered laminate was sintered under the following temperature conditions. The temperature is raised to 400°C at a rate of 200°C per hour and held for 1 hour to decompose and remove the resinous materials in the sheet and paste. Next, the temperature is raised to a softening temperature at 200° C. per hour and maintained, and nucleation for crystal precipitation is performed here. Then, the glass sheet was sintered by increasing the temperature to the crystallization temperature at 200° C. per hour and holding it for 1 minute.

The crystallization temperature was set to the temperature shown in Table 2 for each of A] to A8 in Table 2. In this case, the crystallization temperature is not limited to this, and can be selected, for example, from 750 to 850°C. This temperature is also sufficiently lower than the melting point of the highly conductive metal used here.

Process V: Connection of LSI chip and input/output bin Gold-plated Eval input/output bin is attached to the back side of the board with Au/Sn.
The LSI chips are bonded with solder and the LSI chips are bonded with Pb/Sn solder to form a multilayer wiring board.

The various properties of the glass ceramic obtained in the above process are shown in Table 2 along with its composition. According to this example, the dielectric constant can be set to 5 or less, and an insulating material with an extremely low dielectric constant can be obtained, which is effective for increasing the speed of arithmetic processing.

Also, the coefficient of thermal expansion is approximately 50-70 x 10-77
``The reeds are in the range of C, there is no difference in extra p from the St chip which is approximately 30 x 1o-7/*c, and the adhesiveness of the connection part is good.
Such stress failure does not occur. LSI chip connection life equivalent to that of conventional alumina substrates can be obtained. Moreover, since it has a larger thermal expansion coefficient than conventional glass ceramics, it has good connectivity with highly conductive metals. Therefore, the optimum one can be selected and used depending on the chip and wiring material used. Furthermore, the bending strength is also sufficient.

〔Effect of the invention〕

As mentioned above, since the multilayer circuit board of the present invention uses an insulating material with a low dielectric constant, it is possible to speed up signal propagation, and
The shear joint strength can be improved due to the high flexural strength. In addition, since the coefficient of thermal expansion can be set within an appropriate range, it is possible to conduct wiring using highly conductive materials in order to further speed up signal propagation. It can be used selectively within a range of good properties.

Further, the method for manufacturing a multilayer circuit board of the present invention is advantageous in producing a multilayer circuit board for high-speed signal propagation, since the circuit board can be manufactured by sintering at a temperature below the melting point of a highly conductive metal.

It should be noted that, as a matter of course, the present invention is not limited only to the embodiments described above.

[Brief explanation of the drawing]

The accompanying drawing is a sectional view of a multilayer wiring board according to an embodiment of the present invention.

Claims (1)

[Claims] 1. 66 to 79 wt% of SiO_2, 9 to 79 wt% of Li_2O
20wt%, 3-10wt% of Al_2O_3, K_2
1 to 3 wt% O and TiO_4 or P_2O_
1. A multilayer circuit board characterized in that a circuit is multilayered using a material obtained by mixing 30 to 60 wt% of quartz glass with 70 to 40 wt% of a glassy material containing 3 wt% of silica glass as a glass ceramic insulating material. 2. The multilayer circuit board according to claim 1, wherein the glassy material and quartz glass are both mixed as powder. 3. 66-79 wt% SiO_2, 9-79 wt% Li_2O
20wt%, 3-10wt% of Al_2O_3, K_2
1 to 3 wt% O and TiO_4 or P_2O_
750 to 8
A multilayer wiring board characterized in that it is heat treated at a temperature of 50°C and used as a glass ceramic insulating material to form a multilayer circuit. 4. The multilayer circuit board according to claim 3, wherein the glassy material and quartz glass are both mixed as powder. 5. Lithium silicate (Li_2O・
The multilayer wiring board according to claim 3 or 4, characterized in that 2SiO_2) is precipitated as a main crystal. 6. 66-79 wt% SiO_2, 9-79 wt% Li_2O
20wt%, 3~10w% of Al_2O_3, K_2
1 to 3 wt% O and TiO_4 or P_2O_
A material obtained by mixing quartz glass with a glassy material containing 3 wt% of 5 is heat-treated at a crystal precipitation temperature of 750 to 850 °C,
A method for manufacturing a multilayer circuit board, characterized in that lithium silicate (Li_2O.2SiO_2) is precipitated to form crystallized glass, and this is used as a glass-ceramic insulating material to form a multilayer circuit.