JPH10139559A - Glass-ceramic substrate and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the substrate which has brazing metallization layers capable of effecting sufficient adhesion strength between the substrate and the metallic member at the time of brazing a metallic member such as lead terminal or the like to a glass-ceramic substrate and also to provide the manufacture of the substrate. SOLUTION: In this manufacture, a brazing part used at the time of joining a metallic member 16 to the surface of a glass-ceramic substrate 10 by brazing, has a structure such that the brazing part is formed by successively laminating a first metallization layer 18 contg. the material components of the substrate 10, a second metallization layer 12 contg. none of the material components of the substrate 10 and a brazing filler metal 14 on the lower side of the metallic member 16 in that order from the side of substrate 10 and also, these laminated layers 18, 12 and 14 are buried within the substrate 10, wherein the surface of the brazing part is consistent with the surface of the substrate 10 or formed as a concave surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass-ceramic substrate, and more particularly to a glass-ceramic substrate having a brazed metallization capable of connecting the glass-ceramic substrate and a metal material with a sufficient strength even in a small area, and its manufacture. About the method.

[0002]

2. Description of the Related Art In recent years, in the field of information equipment, the capacity of information has been increased, and the speed of electronic devices such as semiconductors has been increased due to the need to process this large amount of information. Along with this, low-loss characteristics of circuits connecting electronic devices are also required in a multilayer package in which electronic devices are mounted. For this reason, a metal material with low electric resistance such as gold, silver, and copper is used. Pattern formation is performed.

Since the melting point of such a metal is low, conventional alumina which is fired at a high temperature cannot be used as a substrate material, and glass ceramic or the like which can be fired at a low temperature is used.

On the other hand, in such a multilayer package, it is necessary to bond a metal member such as a pin, a lead frame, or a heat sink to the multilayer substrate for connection to the outside and heat radiation. For this purpose, it is necessary to form a metallizing pattern for joining metal members on the substrate,
In a conventional substrate using alumina, tungsten, molybdenum, or the like is used as a metal component of the metallizing pattern.

However, these metals have high melting points and cannot be used for glass ceramics having a low firing temperature. Therefore, in the case of a glass ceramic substrate, the pattern is formed using a metal based on gold, silver or copper.

[0006] These patterns are joined using gold / tin solder, gold / silicon solder, or indium / lead solder. However, since such a bonding member has a low melting point, there has been a problem in that the bonding member is softened by heating at the time of bonding the IC chip and reliability is reduced.

[0007] In order to obtain high reliability using a conventional high melting point silver solder so as not to cause such softening due to heating at the time of bonding of the IC chip, since the solder bonding temperature is high, the There has been a problem that the so-called brazing material is eroded due to alloying of the rising pattern and the silver solder, and the bonding strength between the metallizing pattern and the substrate is reduced.

In order to solve this problem, a conventional metallized layer containing an inorganic binder is formed on a substrate, and a second metallized layer containing no inorganic binder is formed thereon. A proposal has been made to prevent the brazing material from being eroded by the high melting point silver solder and to obtain a large bonding strength (Japanese Patent Laid-Open No. 4-238875).

However, with the recent increase in processing capacity and miniaturization of electronic devices such as semiconductors, an increase in the number of input / output leads of the device and a reduction in the distance between the leads have been demanded. The distance of the lead joint pattern must be reduced, and the pattern width itself must be reduced.

[0010] Under such circumstances, by reducing the pattern width, the bonding area between the pattern and the lead also decreases, so that the strength per unit area must be improved in order to maintain a constant tensile strength. Thus, there has been a problem that the required bonding strength cannot be obtained even by the above-described bonding method.

[0011]

Therefore, the present invention focuses on the fracture mode due to the tension, and it is necessary to obtain a sufficient adhesive strength in brazing a glass ceramic substrate to a metal member such as a lead terminal. It is an object of the present invention to provide a glass ceramic substrate having a brazing metallization that can be formed and a method for manufacturing the same.

[0012]

In the glass ceramic substrate according to the present invention, when a metal member is connected to the glass ceramic substrate by brazing, a brazing portion is formed from the glass ceramic substrate side. A first metallized layer containing the component
Having a structure in which the metallized layer and the brazing material are laminated in this order under the metal member, and the lamination is embedded in the glass ceramic substrate, and the surface of the brazing portion is the same as or concave with the substrate surface. There is a feature.

[0013] Further, according to the manufacturing method of the present invention, a metallizing paste to be a first metallized layer containing a component of a substrate material of a glass ceramic substrate is formed on a ceramic green sheet to be a surface layer of the glass ceramic substrate. A metallizing paste that is a second metallization layer that does not contain, and a paste-like wax are sequentially superimposed and printed, laminated with a ceramic green sheet that is an inner layer of the glass ceramic substrate, pressed, baked, and baked to obtain a brazing surface. Is the same as or concave with the substrate surface.

[0014] Further, the metallizing paste to be the first metallized layer, the metallizing paste to be the second metallized layer, and the portion where the paste wax is to be sequentially superimposed and printed are provided with recesses or holes. It is a concave portion or a hole portion of a ceramic green sheet to be a surface layer of a ceramic substrate.

[0015]

Next, a glass ceramic substrate according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a basic sectional structural view of a connecting portion for brazing metallization of a glass ceramic substrate showing one embodiment of the present invention.

As shown in FIG. 1, the basic structure according to the present invention is provided on the glass ceramic substrate 10 side, that is, on the lowermost layer.
A first metallized layer 18 to which a component of a substrate material of a glass ceramic substrate is added, a second metallized layer 12 containing no such component is formed thereon, and a brazing material 14 is further formed thereon.
Are stacked and embedded in the glass ceramic substrate 10.

By having such a structure, the bonding property between the glass ceramic substrate 10 and the first metallized layer 18 is improved even if the bonding portion has a small area.
Since the connection portion is embedded in the glass ceramic substrate 10 as well, the connection portion can obtain a sufficient adhesive strength as a whole.

For the metallized portion of the present invention, gold, platinum, palladium or the like can be used. For the metallization, a thick film method, a thin film method, or the like can be used in addition to the simultaneous baking method with a substrate described below.

As the brazing material, generally used brazing materials such as silver / copper brazing can be used.

Next, a method for manufacturing the glass ceramic substrate of the present invention will be described below.

First, on a ceramic green sheet to be a surface layer of a glass-ceramic substrate, or on a concave portion of a ceramic green sheet provided with a concave portion or a hole portion, so that a brazing surface becomes the same as or a concave surface after firing. Alternatively, a metallizing paste serving as a first metallized layer 18 containing a component of a substrate material of a glass ceramic substrate, a metallizing paste serving as a second metallized layer 12 not containing the component, and a paste wax 14 are provided in the holes. Print one after the other.

Then, after laminating with a ceramic green sheet as an inner layer of the glass ceramic substrate and pressing, the melting temperature of the brazing and the firing temperature of the glass ceramic substrate are close to each other, so that the firing can be performed, and the metallized layer and the brazing can be performed. A glass ceramic substrate having a material part can be obtained at a stroke.

In the case of a multi-layer substrate, it can be similarly manufactured by previously printing an internal circuit pattern on a ceramic green sheet serving as an internal layer with a conductive paste.

The brazing material portion is formed on the metallized layer 12 of the fired substrate.
It is also possible to provide a concave portion in the upper part of the substrate, and place a paste-like wax or a powder-like wax in the concave portion by printing or the like, and then form it by heating. However, the above-described method is more convenient.

Further, the brazing can be performed on the substrate on which the brazing material portion is formed as described above. However, the brazing material portion is provided by heating the brazing material. Can be placed at the same time.

When completing the present invention, the present inventor
A metallized layer composed of a first metallized layer containing the components of the glass ceramic substrate material and a second metallized layer not containing the components of the glass ceramic substrate material is brazed, and the tensile failure mode is investigated. It was found out that this occurred at the joint surface between the metallized layer of No. 1 and the substrate.

Therefore, in order to increase the strength of the bonding surface, an attempt was made to embed a metallized layer in the substrate. However, this structure did not improve the strength.

In this structure, it has been clarified that the fracture occurs inside the brazing material, which has not been seen so far.

Therefore, in order to obtain a bonding strength that can be used for the current use, it is necessary to prevent the destruction inside the brazing material and to make the bonding strength between the metallized layer and the substrate higher than the strength that can prevent the destruction inside the brazing material. It turned out that it had to be raised.

Therefore, the present invention is intended to increase both the bonding strength between the metallized layer and the substrate and the strength of the brazing material. By forming the brazing material portion in the substrate together with the metallized layer, the present invention provides The bonding strength between the substrate and the substrate is increased, and furthermore, destruction inside the brazing material is prevented.

That is, since the surroundings of the metallized layer and the brazing material portion are held by the substrate material, breakage at both the joint surface between the metallized layer and the substrate and the inside of the brazing material is prevented. I have.

Therefore, the surface of the brazing portion, that is, the surface of the brazing material must be the same as the substrate surface, but the effect of the present invention can be obtained even if the surface is concave.

However, in the case of a convex surface, breakage occurs at a portion that protrudes from the surface of the brazing material during a tensile test.

Since the second metallized layer does not contain the components of the glass-ceramic substrate material, the bonding between the brazing material and the first metallized layer is good, and the substrate and the first metallized layer are not bonded to each other. Is stronger than the joining and brazing material strength.

[0036]

Next, embodiments of the above-mentioned basic structure according to the present invention will be described in detail with reference to specific examples.

(Embodiment 1) FIG. 2 shows a QFP (Quad
FIG. 2 is a plan view showing a state where lead terminals are connected to a flat package (Flat Package) type glass ceramic substrate.

0.5 mm on the glass ceramic substrate 10
Since a large number of lead terminals 16 are connected at a pitch, the area of the lead terminal connection portion is small. For this reason, a glass ceramic substrate having a conventional brazing metallized structure has insufficient bonding strength, and lead terminals are easily peeled off in the brazing.

On the other hand, by using the glass ceramic substrate according to the present invention having the brazing metallization shown in FIG. 1, the brazing portion can obtain a sufficient adhesive strength.

That is, a first metallized layer 18 to which a component of a glass ceramic substrate material is added and a second metallized layer 12 containing no such component are formed in a glass ceramic substrate 10, and further formed thereon. This is a structure in which the brazing material 14 is formed by being overlapped and embedded in the glass ceramic substrate 10.

In the case of this embodiment, the first metallized layer 18
Is palladium (Pd) to which glass alumina of glass ceramic substrate material is added, and the second metallized layer 12 is palladium. As the brazing material 14, copper /
A silver (Cu / Ag) paste was used, and a lead terminal 16 was made of a 42 alloy made of nickel and iron.

As a method of manufacturing the glass ceramic substrate having the brazing metallization, first, a thick film paste which becomes the first metallization layer 18 of palladium (Pd) in which glass-alumina is added to the surface of the ceramic green sheet before firing. Screen printing.

On top of this, a thick film paste to be the second metallized layer 12 of palladium is overlaid and printed,
The silver (Cu / Ag) -based brazing material 14 is overlaid and printed.

Next, on another ceramic green sheet before firing, a thick film paste to be an interlayer conductor is screen-printed together with several sheets to form a multilayer, and after being pressed,
By performing the simultaneous firing for forming the brazing at the same time as the firing of the substrate in a furnace at about 900 ° C., as shown in FIG. 1, the three layers (first metalized layer-second metalized layer-brazing material)
Is obtained as a glass ceramic substrate having a brazed metallized structure embedded in the glass ceramic substrate.

(Embodiment 2) Next, another embodiment of the present invention will be described.

FIGS. 3 and 4 are an external perspective view and a sectional structural view, respectively, of a ceramic package used for a high frequency hybrid integrated circuit module.

In this ceramic package, a frame metal material 22 of a shield side wall made of Kovar is provided around an upper portion of a glass ceramic substrate 20, and a base metal material 24 of a heat sink made of copper / tungsten (Cu / W) is provided below.
Are joined.

In this case, the frame metal material 22 formed so as to surround the periphery of the upper portion has a small connection area and is connected to the glass ceramic substrate 20, so that the conventional brazed metallized structure has good adhesion. Although it was difficult to obtain strength and peeling sometimes occurred, FIG.
By adopting the basic structure shown in (1), sufficient adhesive strength can be obtained.

As a method of manufacturing the glass ceramic substrate, first, a concave portion is provided on the surface of the ceramic green sheet before firing for bonding the frame metal material 22, and glass substrate glass or glass ceramic as a substrate material is added to the concave portion. The thick metal paste to be the first metallized layer 18 of palladium (Pd) to be the first metallized layer is screen-printed.

On top of this, a thick film paste to be the second metallized layer 12 of palladium is overlaid and printed,
The silver (Cu / Ag) -based brazing material 14 is overlaid and printed.

Several ceramic green sheets before firing were screen-printed with a thick film paste to be the interlayer conductor 26, and several layers of the paste were superimposed to form a multilayer, and metallized for connection to the frame metal material 22. Overlay with ceramic green sheet. This multilayer glass ceramic substrate 20 is sandwiched between alumina substrates, pressed, and then fired in a furnace.

A copper / silver (Cu / Ag) solder cut between the multilayer glass ceramic substrate 20, the frame metal member 22, and the base metal member 24 and the multilayer ceramic substrate 20 and the base metal member 24 formed as described above. And heat to braze.

As a result, the brazed portion of the frame metal member 22 has the basic structure shown in FIG. 1 as shown in FIG. 5, and a bond having a sufficient adhesive strength can be obtained. In addition,
FIG. 5 is an enlarged view of a portion indicated by an arrow D in FIG.

[0054]

As is apparent from the above-described embodiment, according to the present invention, the metallization on the glass ceramic substrate when brazing a metal material to the glass ceramic substrate is performed by adding the components of the glass ceramic substrate material. Three layers of one metallization layer, the second metallization layer not containing the above-mentioned components, and the brazing material were embedded in a glass ceramic substrate, and the surface of the brazing portion was the same as the substrate surface or a concave surface.

As a result, since the periphery of the metallized layer and the brazing material portion is held by the substrate material, breakage at the joining surface between the metallized layer and the substrate and the inside of the brazing material is prevented, and the brazing strength is high. A glass-ceramic substrate having an attached metallization can be obtained.

In such a substrate, since the melting temperature of the wax and the firing temperature of the glass ceramic substrate are close to each other, a concave portion or a hole is provided on the ceramic green sheet to be the surface layer of the glass ceramic substrate. A metallizing paste serving as a first metallized layer containing a component of a substrate material of a glass ceramic substrate in a concave portion or a hole of a ceramic green sheet, a metallizing paste serving as a second metallized layer not containing the component, and By sequentially laminating and printing paste-like brazes, laminating with ceramic green sheets serving as internal layers of the glass-ceramic substrate, and sintering, the sintering of the substrate and the formation of the brazing material portion can be performed all at once.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention. It is.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of a connecting portion showing a basic structure of brazing metallization of a glass ceramic substrate according to the present invention.

FIG. 2 is a plan view showing a state where lead terminals are connected to a QFP type glass ceramic substrate to which the glass ceramic substrate according to the present invention is applied.

FIG. 3 is an external perspective view of a ceramic package of a high frequency hybrid integrated circuit module to which the glass ceramic substrate according to the present invention is applied.

FIG. 4 is a sectional structural view taken along line CC of the ceramic package shown in FIG. 3;

FIG. 5 is an enlarged view of a brazing portion between the frame metal material and the glass ceramic substrate, which is indicated by an arrow D in FIG.

[Explanation of symbols]

 Reference Signs List 10 glass ceramic substrate 12 second metallized layer 14 brazing material 16 lead terminal 18 first metallized layer 20 low temperature fired glass ceramic substrate 22 frame metal material 24 base metal material 26 interlayer conductor

Claims (3)

[Claims] 1. A brazing portion when a metal member is connected to a glass ceramic substrate by brazing, the first metallized layer containing a component of the glass ceramic substrate material from the glass ceramic substrate side, and the first metallized layer does not contain the component. A second metallization layer and a brazing material are laminated under the metal member in this order, and the lamination is embedded in the glass ceramic substrate, and the surface of the brazing portion is the same as the substrate surface or a concave surface. A glass ceramic substrate, characterized in that: 2. A metallizing paste serving as a first metallized layer containing a component of a substrate material of a glass ceramic substrate on a ceramic green sheet serving as a surface layer of a glass ceramic substrate, and a second metallized layer not containing said component Metallizing paste, and paste-like brazing are sequentially superimposed and printed, laminated with a ceramic green sheet to be an inner layer of the glass ceramic substrate, and fired so that the brazing surface is the same as the substrate surface or a concave surface. A method for manufacturing a glass ceramic substrate. 3. A glass in which a portion where the metallizing paste to be the first metallized layer, the metallizing paste to be the second metallized layer, and the paste-like solder are sequentially superimposed and printed has a recess or a hole. 3. The method for manufacturing a glass ceramic substrate according to claim 2, wherein the surface is a concave portion or a hole portion of a ceramic green sheet to be a surface layer of the ceramic substrate.