JPH0621656A - Multilayer circuit board and its manufacture - Google Patents

Abstract

PURPOSE:To enhance adhesion and airtight at a metallization boundary of a through hole by forming a conductive metallization part of a high melting paint metal, in a multilayer circuit board having the conductive metllization part. CONSTITUTION:In manufacture of a pin grid ARRAY (PGA) package, a specified through hole is opened on an AlN green sheet, and the through hole of the first layer 2 is packed with a high melting point packing tungsten paste 3 containing a silicon dioxide and magnesium oxide. And, the surface of the first layer 2 is printed with a print tungsten paste 4 containing a silicon dioxide and magnesium oxide. By baking these pastes 3 and 4 under a nitrogen atmosphere, the conductive metallization part having excellent adhesion is obtained. Packing and print tungsten pastes 6, 7:8, 9 are applied to the second layer 5 and the third layer 8 as well, and then baked to obtain a conductive metallization part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer circuit board having a conductive metallized portion and a method for manufacturing the same, and more specifically, in an aluminum nitride multilayer circuit board including a conductive metallized portion, the conductive metallized portion and AlN
The present invention relates to an aluminum nitride multilayer circuit board having improved adhesion at the interface between AlN and a conductive metallized portion by using a conductor paste material suitable for improving the adhesion at the interface with AlN and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, along with the sophistication of electronic circuits, especially miniaturization and high density, a ceramic multilayer substrate having excellent heat dissipation and excellent high-speed transmission has been developed. This multilayer substrate is formed by forming various conductor patterns in layers on a ceramic green sheet and electrically connecting the layers through through holes. As a ceramic substrate, an alumina substrate, a silicon carbide substrate, etc. are known, but recently, an aluminum nitride (AlN) substrate has attracted attention because of its excellent performance. By the way, A
The 1N substrate is provided with a metallized portion for joining with a metal member such as a bonding wire.

At present, a metal such as tungsten (W) or molybdenum (Mo) is used as a metallization for an aluminum nitride substrate and is fired at the same time as AlN.

[0004]

However, in the conventional metallization of W or Mo, these metals and AlN are not used.
The adhesive strength of the interface was insufficient. Therefore, the present invention is
an aluminum nitride multi-layer circuit board having a large interfacial adhesion between an AlN substrate and a metallized portion, which is effective for metallization of an IN substrate and gives a metallized portion excellent in adhesion between the obtained metallized portion and AlN; It is an object to provide a manufacturing method thereof.

[0005]

According to the present invention, there is provided a multilayer circuit board having a conductive metallized portion made of a refractory metal containing silicon dioxide and magnesium oxide.

According to the present invention, a conductor paste made of a refractory metal containing silicon dioxide (SiO ₂ ) and magnesium oxide (MgO) is applied to the surface of the aluminum nitride green sheet, and then the aluminum nitride green sheet is sintered. Thus, there is provided a method for manufacturing an aluminum nitride multilayer circuit board including a step of forming a conductive metallized portion.

According to the present invention, in order to enhance the adhesion between AlN and the metallized interface, SiO ₂ and Mg are contained in the conductor paste.
Add O. As is well known, the conductive paste used for manufacturing a ceramic multilayer circuit board such as an aluminum nitride multilayer circuit board includes tungsten (W), molybdenum (M).
o) and other refractory metals, for example, in the form of powder, to which a binder (eg, ethyl cellulose, polymethyl methacrylate, polyvinyl alcohol, etc.), a solvent (eg, terpineol, etc.) are added, and various additives (eg, calcium carbonate). (CaCO ₃ ), aluminum nitride (AlN), yttria (Y ₂ O ₃ ), titanium compound (TiN
, TiO ₂ ) and other sintering aids and adhesives) are mixed and kneaded.

According to the present invention, however, SiO ₂ and MgO powder are added to the conventional conductor paste as described above. The amount of SiO ₂ and MgO to be added is not particularly limited, but is preferably approximately the same as the amount of CaCO _{3 which is} the sintering additive used for the AlN green sheet, and SiO ₂ : MgO
The (molar ratio) is preferably 1: 1 to 3: 1.

The conductor paste material according to the present invention can be applied to an aluminum nitride green sheet and simultaneously sintered to obtain a multilayer circuit board, wherein, for example, CaCO ₃ , Y ₂ O ₃ or the like is used. The sintering aid is preferably 0.1 to 5 during the production of the aluminum nitride green sheet.
The adhesive force between the aluminum nitride and the metallized interface can be remarkably increased by adding a weight% to form a sheet, applying a conductor paste to the sheet, and simultaneously sintering the sheet at 1700 to 1900 ° C. in a nitrogen atmosphere.

[0010]

According to the present invention, SiO ₂ and M are contained in the conductor paste.
By adding gO, applying it to an AlN green sheet, and simultaneously firing it, the adhesion between the AlN and the metallized interface can be increased. Further, it is preferable to add it as a sintering aid such as CaO in order to promote the sinterability of AlN, and it is not intended to limit the content of the present invention, but this makes it possible to add SiO ₂ --MgO--CaO to the interface between AlN and the metallized layer.
It is assumed that the vitreous substance is produced and the desired adhesion is obtained.

[0011]

EXAMPLES The contents of the present invention will be described in more detail below with reference to Examples, but it goes without saying that the scope of the present invention is not limited to the following Examples. An example in which tungsten is metallized to aluminum nitride to form a PGA (pinglit array) package will be described.

1. Manufacture of AlN green sheet 100 parts by weight of AlN powder, sintering aid (CaCO ₃ , 40 parts by weight),
Binder (PVA, 9 parts by weight), plasticizer (DBP, 3
Parts by weight), dispersant (1 part by weight) and solvent (ethanol)
A slurry was prepared by using the above method, and a green sheet was prepared by a doctor blade method according to a conventional method (thickness: about 350 μm).

2. Production of Tungsten Paste Tungsten powder (average particle size: 1.5 μm, 100 parts by weight), binder (ethyl cellulose, 3 parts by weight), solvent (terpineol) and SiO ₂ and MgO in the same ratio as the sintering aid (CaCO ₃ ). In addition, it was made into a paste. In addition,
The tungsten paste for printing and the tungsten paste for filling were adjusted by the viscosity of the solvent.

3. Production of PGA A PGA having a pin 1 having a structure as shown in FIG. 1 was produced. The AlN green sheet obtained above is punched into a predetermined shape by sheet punching, and a predetermined through hole is formed in this. Then, the filling tungsten paste 3 is filled into the through holes of the first layer 2 of the AlN sheet 2 to form AlN.
The printing tungsten paste 4 is printed on the surface of the first layer 2 of the sheet. These filling tungsten pastes 3
The tungsten paste 4 for printing is turned into a tungsten metallization by, for example, sintering at 1650 to 1900 ° C. for 9 to 15 hours in a nitrogen atmosphere. Similarly, the filling tungsten paste 6 is filled into the through holes of the second layer 5 of the AlN sheet, the printing tungsten paste 7 is printed on the surface of the sheet 5, and the through holes of the third layer 8 of the AlN sheet are similarly formed. The holes are filled with the filling tungsten paste 9, and the surface of the sheet 8 is printed with the tungsten paste 10 for printing.
Can be printed to obtain a PGA having the structure of FIG.

The adhesion between the AlN sheet of PGA and the tungsten metallized interface obtained above is strong and it is destruction from the inside of the ceramic.
A significant improvement was observed in comparison with the adhesive force (peeling at the interface between tungsten and metallization) obtained in the same manner as above except that O ₂ and MgO were not added. The other properties of the obtained PGA were not found to have any adverse effect on these properties electrically or in an environmental test.

[0016]

As described above, according to the present invention,
By adding SiO ₂ and MgO to the refractory metal paste material such as tungsten, the adhesiveness of the interface is strong in the through hole portion, the airtightness is improved, and the adhesive strength is also improved in the conductor pattern. .

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a PGA type aluminum nitride multilayer circuit board according to the present invention.

[Explanation of symbols]

1 ... Pins 2, 5, 8 ... AlN 3, 6, 9 ... Tungsten metallization (filling through holes) 4, 7, 10 ... Tungsten metallization (surface printing)

Claims (3)

[Claims] 1. A multilayer circuit board having a conductive metallized portion made of a refractory metal containing silicon dioxide and magnesium oxide. 2. A step of forming a conductive metallized portion by applying a conductor paste made of a refractory metal containing silicon dioxide and magnesium oxide to the surface of an aluminum nitride green sheet and then sintering the aluminum nitride green sheet. A method of manufacturing a multilayer circuit board, comprising: 3. The aluminum nitride green sheet contains a sintering aid, and the silicon dioxide and magnesium oxide are added in the same ratio as the sintering aid. Manufacturing method of multilayer circuit board.