JPH0697660A - Multi-layer ceramics substrate and its manufacture - Google Patents

Abstract

PURPOSE:To provide a multi-layer ceramics substrate and its manufacturing method, with which the connection reliability between the thick film via formed inside and the thin film pad formed on a surface is improved. CONSTITUTION:Multiple laminated inner layer substrates 24, containing a thick film pattern, a thick film via 28 and a thick film pad 30 formed to face the thick film via 28, respectively, multiple grinding layer substrates 26 containing thick film vias 32 and thick film pads 34 formed to face the thick film via 32, respectively, laminated on the upper and lower sides of the substrate 24, and thin film pads 38 formed on the upper and lower sides of the grinding layer substrate 26 are provided to constitute a multi-layer ceramics substrate. And at least at multiple layers of the grinding layer substrate 26, on upper and lower sides, multiple thick film vias 32 are connected to one thick film pad 34, and at the same time, one thin film pad 38 is connected to multiple thick film vias 34 on upper and lower sides of the grinding layer substrate 26.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Electronic devices such as computers and electronic exchanges that process a large amount of information are required to be smaller, more reliable, and faster, and therefore higher density of electronic circuits is required. It Therefore, a chip (semiconductor element)
We are increasing the degree of integration of ourselves and dealing with demands.

Recently, with the demand for high-density mounting and high-speed mounting, a technique for mounting a chip on a multilayer ceramic substrate having good heat dissipation and suitable for high-speed processing has been developed. Along with the increase in packaging density, it is widely used to polish a thick film circuit board and then form a thin film circuit on the surface, which can further improve the reliability of thick film-thin film connection when manufacturing a multilayer ceramic substrate. Is required.

[0003]

2. Description of the Related Art FIG. 3 shows a sectional view of a conventional example.
(A) shows the thick film circuit board 2 after firing, and (B) shows the multilayer ceramic substrate 12 having a thin film circuit formed on the surface after polishing.

The thick film circuit board 2 is composed of a plurality of inner layer substrates 4 and polishing layer substrates 6 laminated on and below the inner layer substrate 4. A thick film via 8 and a thick film pad 10 on the inner layer substrate 4;
A thick film pattern (not shown) is formed, and a thick film via 8 and a thick film pad 10 are formed on the polishing layer substrate 6. Both the inner layer substrate 4 and the polishing layer substrate 6 are formed by thermocompressing green sheets and firing at a predetermined temperature for a predetermined time.

FIG. 3B shows a multilayer ceramic substrate 1 as a finished product in which a thin film pad 14 is formed on the surface of the thick film circuit board 2 after polishing the surface to obtain flatness and parallelism.
2 is shown. The thin film pad 14 is formed by sputtering copper, aluminum, etc., and then etching it into a predetermined pattern.

[0006]

In the conventional multi-layer ceramic substrate 12, one thin film pad 14 is connected to one thick film via 8 as shown in the figure.
Thick film via 8 with ppm establishment (once every 100,000 times)
There was a problem that a connection failure between the thin film pad 14 and the thin film pad 14 occurred.

The present invention has been made in view of the above points, and an object thereof is to improve the reliability of connection between a thick film via formed inside and a thin film pad formed on the surface. It is an object of the present invention to provide a multilayer ceramic substrate and a method for manufacturing the same.

[0008]

According to the present invention, a plurality of stacked inner layer substrates each having a thick film pattern, a thick film via, and a thick film pad formed at a position facing the thick film via. And a plurality of polishing layer substrates each having a thick film via and a thick film pad formed at a position facing the thick film via, which are stacked on the front and back of the laminated inner layer substrate,
In a multilayer ceramic substrate composed of thin film pads formed on the front and back surfaces of the polishing layer substrate, a plurality of thick film vias are connected to one thick film pad in a plurality of layers on at least the front and back sides of the polishing layer substrate. In addition, a multilayer ceramic substrate is provided in which one thin film pad is connected to the plurality of thick film vias on the front and back of the polishing layer substrate.

Preferably, 1 is used for all of the polishing layer substrates.
A plurality of thick film vias are connected to each thick film pad. According to another aspect of the present invention, the first green sheet with holes is filled with a conductor to form a first thick film via, and a conductor is printed on the first green sheet to form a thick film pattern. The first thick film pad is formed and the second hole is punched.
Second thick film for forming a second thick film via by filling the green sheet of the above with a conductor, and printing a conductor on the second green sheet to connect to a plurality of the second thick film vias. A pad is formed, a plurality of layers of the first green sheet are laminated, a plurality of layers of a second green sheet are laminated above and below the laminated first green sheet, and the laminated body is pressed while being heated. Each of the first and second green sheets by pressure bonding, the pressure-bonded laminated body is fired at a predetermined temperature for a predetermined time, and the upper and lower surfaces of the fired laminated body are polished to obtain desired flatness and parallelism. A method of manufacturing a multilayer ceramic substrate is provided, which comprises forming thin film pads connected to a plurality of the second thick film vias on a polished surface.

[0010]

A multilayer ceramic substrate is manufactured by polishing a thick film circuit substrate in which an inner layer substrate and a polishing layer substrate are laminated to obtain flatness and parallelism, and then forming a thin film pad on the surface. Since the thin film pad is connected to multiple thick film vias, even if one thick film-thin film connection part becomes abnormal and connection failure occurs, it will function properly if the other connection part is normal. Therefore, the connection reliability of the thick film-thin film connection portion can be improved.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 is an exploded cross-sectional view of a multilayer ceramic substrate according to an embodiment of the present invention, FIG. 2 (A) is a cross-sectional view of a thick film circuit board that has been fired, and FIG. 2 (B) is a polished thin film circuit. It is sectional drawing of a multilayer ceramic substrate.

Referring to FIG. 2A, a plurality of inner layer substrates 24 and a polishing layer substrate 2 stacked above and below the inner layer substrate 24.
A thick film circuit board 22 consisting of 6 and 6 is shown. The inner layer substrates 24 are, for example, several tens of layers stacked, and each inner layer substrate 2
4 includes a plurality of thick film vias 28 and each thick film via 28.
A plurality of thick film pads 30 connected to each other and a thick film pattern (not shown) are formed. The thick film via 28, the thick film pad 30, and the thick film pattern are made of, for example, copper.

The polishing layer substrate 26, which is a plurality of layers laminated on the inner layer substrate 24, is a substrate to be polished to an arbitrary position in order to obtain the flatness and parallelism of the entire substrate. Two thick film vias 32 for each thick film via 28
Are formed, and one thick film pad 34 is connected to the two thick film vias 32.

The inner layer substrate 24 and the polishing layer substrate 26 are formed, for example, by laminating glass ceramic green sheets, thermocompression-bonding them, and firing them at a predetermined temperature for a predetermined time.

The manufacturing process of the multilayer ceramic substrate of the embodiment of the present invention will be described below. First, a first green sheet made of glass ceramics, which is an inner layer substrate, is punched and filled with copper to form a first thick film via 28. Then, copper is screen-printed on the first green sheet to form a first thick film pad 30 and a thick film pattern (not shown).

The thick film pattern formed on the inner layer substrate 24 is different for each substrate and serves as a signal layer, a power source layer or a ground layer, respectively. Further, the second green sheet made of glass ceramics to be the polishing layer substrate 26 is perforated, and these holes are filled with copper to form the second thick film via 3
Form 2. Next, copper is screen-printed on the second green sheet to form second thick film pads 34 that connect to the two second thick film vias 32, respectively.

Since the second green sheet is fired to form the polishing layer substrate 26, no thick film pattern is formed on the second green sheet. A plurality of layers of the first green sheet processed as described above are laminated, and a plurality of second green sheets are laminated above and below the laminated first green sheet.

While heating the laminated body at about 100 to 150 ° C., each green sheet is thermocompression-bonded by applying a pressure of about 300 kg / cm ² . Next, the pressure-bonded laminated body is about 100
The thick film circuit board 22 is manufactured by firing at 0 ° C. for about 2.5 hours.

Next, the polishing layer substrates 26 on the upper and lower surfaces of the baked thick film circuit substrate 22 are polished to arbitrary positions so as to obtain desired flatness and parallelism. Next, a film of, for example, aluminum is formed on the polished substrate by sputtering, and is etched to form the thin film pad 38 connected to the two thick film vias 32 formed on the polishing layer substrate 26. The thickness of the thin film pad 38 is several μ
It is about m.

The multilayer ceramic substrate 36 thus formed is shown in FIG. 2 (B). Figure 1 is Figure 2 (B)
3 is an exploded sectional view of the multilayer ceramic substrate shown in FIG. 2A and 2B, each inner layer substrate 24
The boundary line between the polishing layer substrate 26 and the polishing layer substrate 26 is shown only for the sake of convenience of description and for the sake of understanding. In the fired actual multilayer ceramic substrate, each inner layer substrate 24 and polishing layer substrate 26 are shown. 26 is integrated so that these boundaries are indistinguishable.

According to this embodiment, since the thin film pad formed on the surface of the substrate is connected to the two thick film vias, one thick film-thin film connection portion has some abnormality and a connection failure occurs. Also in this case, if the other thick film-thin film connection portion is normal, the entire circuit can function normally.

In the above-described embodiment, two thick film vias are connected to one thin film pad, but the present invention is not limited to this structure and one thin film pad is connected. It includes a structure in which three or more thick film vias are connected together.

[0023]

Since the multilayer ceramic substrate of the present invention is configured as described above in detail, the connection chance of thick film-thin film can be multiplied by an integer. Therefore, the thick film via formed inside and the thin film formed on the surface are formed. This has the effect of improving the reliability of connection with the pad.

[Brief description of drawings]

FIG. 1 is an exploded sectional view of a multilayer ceramic substrate according to an embodiment of the present invention.

2A and 2B are cross-sectional views of an embodiment of the present invention, in which FIG. 2A is a thick film circuit board after firing, and FIG. Shows.

FIG. 3 is a cross-sectional view of a conventional example, (A) shows a thick film circuit board, and (B) shows a completed multilayer ceramic board.

[Explanation of symbols]

 22 Thick Film Circuit Board 24 Inner Layer Substrate 26 Polishing Layer Substrate 28,32 Thick Film Via 30,34 Thick Film Pad 36 Multilayer Ceramic Substrate 38 Thin Film Pad

Claims (5)

[Claims] 1. A thick film pattern and a thick film via (28), respectively.
And a plurality of laminated inner layer substrates (24) having thick film pads (30) formed at positions facing the thick film vias (28),
A plurality of thick film vias (32) stacked on the front and back of the stacked inner layer substrate (24), and thick film pads (34) formed at positions facing the thick film vias (32). Polishing layer substrate (2
6) and a thin film pad formed on the front and back of the polishing layer substrate (26)
A multilayer ceramic substrate composed of (38) and a plurality of thick film vias (32) are connected to one thick film pad (34) by a plurality of layers on at least the surface side of the polishing layer substrate (26). The plurality of thick film vias (34) are provided on the front and back of the polishing layer substrate (26).
A multi-layer ceramic substrate characterized by connecting individual thin film pads (38). 2. The multilayer ceramic according to claim 1, wherein a plurality of thick film vias (32) are connected to one thick film pad (34) in all of the polishing layer substrates (26). substrate. 3. The multilayer ceramic substrate according to claim 1, wherein the inner layer substrate (24) and the polishing layer substrate (26) are made of glass ceramics. 4. The thick film via (28, 32), the thick film pad (30,
34) The multilayer ceramic substrate according to any one of claims 1 to 3, wherein the thick film pattern is formed of copper, and the thin film pad (38) is formed of aluminum. 5. A first thick film via (28) is formed by filling the perforated first green sheet with a conductor, and a conductor is printed on the first green sheet to form a thick film pattern and a first thick film pattern. 1 thick film pad (30) is formed, the second green sheet with holes is filled with a conductor to form a second thick film via (32), and a conductor is printed on the second green sheet. To form a second thick film pad (34) connected to a plurality of the second thick film vias (32), and stacking a plurality of layers of the first green sheet,
A plurality of second green sheets are laminated on the upper and lower sides of the laminated first green sheet, and the laminated body is pressurized while being heated, so that each of the first and second green sheets is pressure-bonded and pressure-bonded. The laminated body is fired at a prescribed temperature for a prescribed time, the upper and lower surfaces of the fired laminated body are polished to obtain desired flatness and parallelism, and the second thick film via (34) is formed on the polished surface. A method of manufacturing a multilayer ceramic substrate, comprising forming a thin film pad (38) connected to a plurality of layers.