JPH05251584A - Manufacture of ceramic chip carrier - Google Patents

Abstract

PURPOSE:To prevent shortcircuit with ant adjacent through-hole and to divide a ceramic substrate without pulling a conductor to one side to cause breakage at a through-hole part or without generating cracks by applying cupric oxide paste of low viscosity whose volume is larger than that of copper to a through- hole which becomes a side electrode. CONSTITUTION:A green sheet wherein conductor print and via burying are carried out is thermo-compressed and laminated to form a through-hole. It is notched to connect each through-hole if necessary. Cupric oxide-based conductor paste is printed on the inner wall of a through-hole to form a conductor layer 35A. A lamination wherein print is performed is unbound and burnt in nitrogen atmosphere. A scribe line 41 is formed on a through-hole of the burnt substrate and the substrate is divided into pieces. Since cupric oxide paste applied to a through-hole is deoxidized and becomes a thin conductor film after burnt, a ceramic substrate can be divided into pieces without generating cracks, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a ceramic chip carrier for mounting semiconductor LSIs, chip parts and the like and interconnecting them.

[0002]

2. Description of the Related Art In order to increase the mounting density on a wiring board, there is a ceramic chip carrier type package IC as shown in the perspective view of FIG. In FIG. 3, 31 is a side electrode, 32 is a wiring substrate, 33 is an electrode pad, and 34 is a chip carrier. This is a packaged IC
An electrode pad 33 that can be soldered is drawn out on the back surface of the wiring board, and is directly connected to the conductor surface of the wiring board 32 by soldering.

This type of packaged IC has a wiring board 32.
The mounting area above is about 1 / th that of the conventional DIP DIP with the same number of pins
The number can be set to 3 or less, and mounting can be performed at a higher density than that of a flat package type IC. It is also easy to install and replace, and is lightweight. A ceramic substrate is generally used for the chip carrier 34.

Therefore, an example of a method of manufacturing the side electrode 31 for connecting the wiring board 32 and the chip carrier 34 will be described. First, a through hole 35 is formed along the outer shape of the ceramic substrate of the chip carrier 34 to be separated into individual pieces on the green sheet laminated body made of the inorganic composition before firing, to form a perforated laminated body. Next, the ceramic substrate of the chip carrier 34 is fired. Conductor is printed on the through hole 35 of the ceramic substrate of the chip carrier 34 while sucking a conductive paste such as copper from the bottom, and the conductor is formed on the inner wall of the through hole (through hole conductor layer)
To form. However, in this case, since the inner wall of the through hole cannot be completely coated with the conductor, the inner wall of the through hole is completely coated with the conductor after firing by firing while drawing the conductor paste into the through hole from the back side. The ceramic substrate of the chip carrier 34 having the conductor (side electrode 31) on the side surface can be manufactured by dividing the through hole at the center (scribe line).

[0005]

According to the above-mentioned manufacturing method, the following problems have become clear. FIG. 4 is a perspective view showing a fracture surface of a side electrode portion of the above-mentioned conventional ceramic chip carrier type.
When the ceramic substrate 30 of 34 is divided into individual pieces along the scribe line 41 to form the chip carrier 34 shown in FIG. 3,
At a place where the conductor of the through hole 35 (through hole conductor layer 35A) is thick, one conductor (through hole conductor layer 35A) is not broken at the scribe line 41 as shown in FIG. 4 in the right direction), the ceramic portion 30A is fractured at the position shown by the fracture portion 30B, and the semi-cylindrical side electrode 31 is not formed.
There was a problem that 33 remained on one side and the ceramic substrate 30 was cracked.

In addition, when a step of adding a notch to the ceramic substrate before firing is added to facilitate the division after firing, when printing is performed while sucking the conductor paste from below onto the fired ceramic substrate with the notch. , Conductor flows into the notch groove, causing a short circuit.

The present invention solves the above-mentioned conventional problems, and when a ceramic substrate for the purpose of obtaining a large number of chip carriers is divided into individual pieces, the conductor is pulled to one side at the through-hole portion and peeled or cracked. I wo n’t go in,
Further, since the cupric oxide paste is printed on the through holes before firing, the purpose is to prevent the conductor from flowing into the notch groove and causing a short circuit with the adjacent through hole.

[0008]

According to the present invention, a desired number of green sheets printed with a paste containing at least cupric oxide as a main component are laminated, and then a through hole is formed in the laminated body. A conductor is printed on the inner wall of the wiring pattern and the through hole while sucking the paste containing cupric oxide as the main component on both sides and one side. This printed laminated body is debound, subjected to reduction heat treatment,
It is manufactured by breaking so as to divide the ceramic substrate and the through hole, which are made by firing in a nitrogen atmosphere.

[0009]

According to the present invention, the through-holes to be the side electrodes are applied in the form of cupric oxide paste having a low viscosity and a volume larger than that of copper. Therefore, after firing, it is reduced to copper having a small volume to form a thin conductor film. it can. Therefore, it becomes easy to divide.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The substrate composition ceramic powder was used as an inorganic component, polyvinyl butyral as an organic binder, di-n-butyl phthalate as a plasticizer, and a mixed solution of toluene and isopropyl alcohol (30:70 weight ratio) as a solvent was mixed to form a slurry. .. This slurry was formed into a green sheet on an organic film by the doctor blade method. At this time, a system was used in which each step of drying, punching, and forming the film is continuously performed.

A desired number of the green sheets on which conductor printing and via filling were performed were prepared and thermocompression bonded to form a laminate. Here, a desired number of through holes were formed along the outer shape of each chip carrier into a plurality of chip carrier pieces on the laminated body. The diameter of this through hole was 400 μm.
A notch was formed to connect each through hole if necessary.

Next, in order to form a conductor layer on the inner wall of the through hole, a conductor paste was printed on the through hole by suction from below the laminated body. The conductor paste is an organic binder containing 5 wt% of CuO powder (average particle size 3 μm) and glass frit (# 7059 glass powder manufactured by Corning, average particle size 3 μm) for obtaining connection strength as an inorganic component. A vehicle prepared by dissolving ethyl cellulose in terpineol was added and mixed with a three-stage roll so as to have an appropriate viscosity.

The thus printed laminate was debindered in air at a temperature of 600 ° C. Then, the laminated body was reduced in an atmosphere of 100% hydrogen gas at 300 ° C. for 5 hours. When the copper layer at this time was analyzed by X-ray diffraction, it was 10
It was confirmed to be 0% copper. Finally, it was baked in pure nitrogen in a mesh belt furnace at 900 ° C. Next, a scribe line was put on the through hole of the fired substrate with a laser cutter to divide into individual pieces.

Observing the fracture surface of the produced chip carrier 34, as shown in the perspective view of FIG.
Through-hole conductor layer 35A and ceramic part 30A at 41
Was ruptured cleanly, and as shown in FIG. 4, the conductor was not pulled by one side to be peeled off or cracked. It was also confirmed that the flow of the cupric oxide paste into the through hole was sucked up to the opposite side of the substrate.

The flow of the cupric oxide paste into the notch groove when the notch was inserted showed almost no such phenomenon, and no short circuit was observed.

An example of a chip carrier type ceramic multilayer wiring board having wiring in the inner layer is shown in the perspective view of FIG. Figure 2
In, parts such as LSI are mounted. Reference numeral 21 is an LSI, 22 is a ceramic portion, 23 is an internal conductor, 24 is a surface conductor, and 25 is a side electrode.

[0018]

As described above, according to the method of manufacturing a ceramic chip carrier of the present invention, when a substrate for the purpose of taking a large number of chip carriers is divided into pieces, the conductor is pulled to one side at the through hole portion and peeled off. It also eliminates cracks. Further, since the cupric oxide paste is printed on the through hole portion before firing, the conductor does not flow into the notch groove and short-circuit with the adjacent through hole is prevented.

[Brief description of drawings]

FIG. 1 is a view showing a fracture surface of a side electrode portion of a ceramic chip carrier type produced by a manufacturing method of the present invention.

FIG. 2 is a perspective view showing an example of a chip carrier type ceramic multilayer wire substrate.

FIG. 3 is a perspective view of a conventional ceramic chip carrier type package IC.

FIG. 4 is a perspective view showing a fracture surface of a side electrode portion of a conventional ceramic chip carrier type.

[Explanation of symbols]

21 ... LSI, 22 ... Ceramic part, 23 ... Internal conductor,
24 ... Surface conductor, 25 ... Side electrode (through hole),
30 ... Ceramic substrate of chip carrier 34, 30A ... Ceramic part, 30B ... Ceramic breakage part, 31 ... Side electrode (through-hole conductor layer 35A), 32 ... Wiring board, 33 ...
Electrode pad, 34… Chip carrier, 35… Through hole, 41… Scribe line.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H05K 3/46 H 6921-4E

Claims (3)

[Claims] 1. A paste containing at least cupric oxide as a main component is printed to laminate a desired number of green sheets, and then through holes are formed in this laminate, and the second oxide on both sides and one side of the laminate is formed. A conductor is printed on the inner wall of the wiring pattern and the through hole while sucking the paste containing copper as a main component. A method of manufacturing a ceramic chip carrier, comprising debinding the printed laminated body, performing a reducing heat treatment, and breaking the ceramic substrate made by firing in a nitrogen atmosphere so as to divide a through hole. 2. The method of manufacturing a ceramic chip carrier according to claim 1, wherein a scribe line is provided on the through hole of the ceramic substrate after firing. 3. The method of manufacturing a ceramic chip carrier according to claim 1, wherein after forming through holes in the laminated body, notches are formed so as to connect the through holes.