JPH0661650A - Production of multilayer ceramic board - Google Patents

Abstract

PURPOSE:To facilitate formation of an outermost wiring pattern by removing a columnar electrode in flush with a compositional sheet of a board. CONSTITUTION:A compositional sheet 1 of a board and a contraction suppressing sheet 2 are formed on a film 3. A hole is drilled through both sheets and subsequently filled with a conductor paste 4. A plurality of compositional sheets 1 are then laminated sequentially between uppermost and lowermost contraction suppressing sheets 2. An inner layer conductor pattern 5 is foamed between the compositional sheets 1 at that time. The laminate of sheets is then sintered at such temperature as only a compositional sheet 1 made of low temperature sintering material is sintered and the uppermost and lowermost contraction suppressing sheets 2 not sintered under that temperature, are removed thus forming a columnar electrode 6. The columnar electrode 6 is then machined aligning the upper and lower surfaces of the compositional sheet 1 thus forming an outermost wiring pattern easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multi-layer ceramic substrate on which a semiconductor LSI, chip parts, etc. can be mounted and which can be easily interconnected.

[0002]

2. Description of the Related Art In recent years, a multilayer ceramic substrate is required to have a high density in accordance with the rapid progress of devices, and the increase in the number of pins due to the digitization of circuits, the narrower pitch and the surface mounting of the mounting form, Is advancing to flip chip mounting.

However, the multilayer ceramic substrate has a problem that shrinkage occurs due to sintering during firing. The shrinkage due to the sintering varies depending on the substrate material used, the green sheet composition, the powder lot, and the like, which causes some problems in the production of the multilayer ceramic substrate.

First, in manufacturing a multilayer ceramic substrate, the inner layer wiring is fired and then the outermost layer wiring such as the uppermost layer is formed. Therefore, when the shrinkage error of the substrate material is large, the outermost layer wiring pattern and the inner layer wiring are formed. Since it is not possible to connect to the electrodes, it is necessary to form a land with a larger area than necessary in the outermost layer electrode part so as to predict and correct the shrinkage error, which is suitable for circuits that require high-density wiring. Causes problems. In addition, there is a method of preparing several screen plates for the wiring of the outermost layer according to the shrinkage error and using them according to the shrinkage rate of the multilayer ceramic substrate. It is uneconomical to prepare.

On the other hand, if the wiring of the outermost layer is performed simultaneously with the firing of the inner layer, a large land is not required. However, since the shrinkage error of the multilayer ceramic substrate itself remains as it is by this simultaneous firing method, the cream when mounting the last component In solder printing, there may be a case where printing cannot be performed on a necessary portion due to the error. Also, when mounting components, a deviation from a predetermined component position occurs.

Secondly, the multilayer ceramic substrate produced by the green sheet laminating method has a different shrinkage factor depending on the film-forming direction of the green sheet depending on the width direction and the longitudinal direction, which is an obstacle to the production of the multilayer ceramic substrate.

In order to reduce these shrinkage errors as much as possible, it is necessary to control not only the substrate material and the green sheet composition but also the lamination conditions such as the difference in powder lot, the press pressure, and the temperature in the manufacturing process. is there. However, it is generally said that the shrinkage ratio error is about ± 0.5%. This is a problem common to those involving the sintering of multilayer ceramic substrates.

Therefore, in manufacturing a ceramic substrate, a substrate-constituting sheet is prepared, an electrode pattern is formed with a conductor paste, and a desired number of sheets on which another electrode pattern has been formed are laminated with the substrate-constituting sheet. A shrinkage suppression sheet that does not sinter at the firing temperature of the substrate-constituting sheet is laminated on both sides or one side of the laminate so that the laminate is fired. Thereafter, the shrinkage-restraining sheet that does not sinter is removed to produce a multilayer ceramic substrate that does not shrink during firing. Hereinafter, a method for manufacturing the above-mentioned conventional multilayer ceramic substrate will be described.

As shown in FIGS. 3 (a) and 3 (b), the substrate constituting sheet 11 and the shrinkage suppressing sheet 12 are formed on the film 13 by a sheet forming process. Shrinkage suppression sheet 12
As the material of (1), a material having a sintering temperature higher than that of the substrate constituting sheet 11 is used. The board-constituting sheet 11 thus formed is perforated as shown in FIG. 3C, and the holes are filled with the conductor paste 14. Next, as shown in FIG. 3D, the shrinkage suppression sheet 12 is the uppermost layer and the lowermost layer,
A plurality of substrate component sheets 11 are sequentially laminated inside the sheet. At this time, the inner layer conductor pattern 15 is formed between the substrate constituting sheets 11. This laminated sheet is fired at a temperature at which only the substrate constituent sheet 11 is sintered and the shrinkage suppression sheet 12 is not sintered. Then, as shown in FIG. 3E, by removing the non-sintered shrinkage suppression sheet 12, a multilayer ceramic substrate having no shrinkage difference can be manufactured.

[0010]

However, in the above-mentioned conventional method, when the wiring patterns are formed on the outermost layers such as the uppermost layer and the lowermost layer of the substrate constituting sheet 11 after removing the shrinkage suppressing sheet 12, the internal electrodes, In particular, a wiring pattern of the outermost layer is formed by an insulating layer formed by reacting the glass component of the internal electrode portion in contact with the outermost layer of the substrate constituent sheet 11 and the shrinkage suppressing sheet 12 with alumina of the composition of the shrinkage suppressing sheet 12. It had a problem that it could not be done.

The present invention solves the above-mentioned problems of the prior art by preventing the reaction between the glass component of the internal electrode in contact with the outermost layer of the substrate-constituting sheet and the shrinkage suppressing sheet and the alumina of the shrinkage controlling sheet, Moreover, it is an object of the present invention to provide a method for manufacturing a multilayer ceramic substrate, which can prevent the formation of an insulating layer and easily form an outermost wiring pattern.

[0012]

In order to achieve this object, a method for manufacturing a multilayer ceramic substrate according to the present invention is to fill a conductor paste into holes formed in both a substrate constituent sheet and a shrinkage suppression sheet to form an electrode. This is a method of forming a shrinkage-suppressing sheet as the outermost layer, firing a multilayer sheet in which a plurality of substrate-constituting sheets are sequentially laminated inside, and then removing the outermost shrinkage-restraining sheet and the columnar electrodes thereof.

[0013]

In this method, the reaction between the alumina of the composition of the shrinkage suppressing sheet and the glass component of the internal electrode is prevented, and the insulating layer is not formed on the outermost layer of the substrate constituting sheet.

[0014]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1A and 1B, the substrate-constituting sheet 1 and the shrinkage-restraining sheet 2 are formed on the film 3 by a sheet forming method. The material of the substrate component sheet 1 is
It is a low temperature sintering material containing glass in alumina, and the material of the shrinkage suppression sheet 2 is a material having a sintering temperature higher than that of the substrate constituent sheet 1, for example, pure alumina, boron nitride, magnesium oxide and the like. Both sheets thus formed are perforated as shown in FIGS. 1 (c) and 1 (d),
The hole is filled with the conductor paste 4. Copper oxide is generally used as a main material of the conductor paste 4, but other materials such as silver, an alloy of silver and palladium, an alloy of silver and platinum, and copper may be used. Next, as shown in FIG. 1E, the shrinkage suppression sheet 2 is used as the uppermost layer and the lowermost layer, and a plurality of substrate component sheets 1 are sequentially laminated. At this time, the inner layer conductor pattern 5 is formed between the substrate constituting sheets 1.
If this laminated sheet is fired at a temperature at which only the substrate-constituting sheet 1 made of a low-temperature sintering material is sintered, and only the uppermost layer and the lowermost layer of the shrinkage suppression sheet 2 not sintered at this temperature are removed,
The columnar electrodes 6 are formed as shown in FIG. Further, as shown in FIG. 1G, the columnar electrodes 6 are processed and removed so as to be flush with the upper and lower surfaces of the substrate constituting sheet 1.

As described above, according to this embodiment, the columnar electrodes 6 are formed by forming holes in the shrinkage suppressing sheet, printing and firing the conductor paste, and removing the columnar electrodes 6 in accordance with the surface of the substrate constituting sheet. A wiring pattern of the outermost layer, which prevents the reaction between the glass component of the internal electrode in contact with the outermost layer of the substrate constituent sheet 1 and the shrinkage suppressing sheet 2 and the alumina of the composition of the shrinkage suppressing sheet 2, and prevents the formation of an insulating layer. Can be easily formed.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

As described with reference to FIGS. 1 (a) to 1 (e) of the first embodiment, the shrinkage suppressing sheet 2 is the uppermost layer and the lowermost layer as shown in FIG. 2 (a), A plurality of substrate constituting sheets 1 are sequentially laminated. After firing this laminated sheet at a temperature at which only the substrate-constituting sheet 1 is sintered,
As shown in (b), the columnar electrodes 6 included in the uppermost layer and the lowermost layer of the shrinkage suppression sheet 2 which are not sintered and the shrinkage suppression sheet 2
Are removed at the same time. At this time, the columnar electrodes 6 are removed according to the surface of the substrate constituting sheet 1.

The present embodiment differs from the first embodiment in that the columnar electrodes 6 are removed at the same time as the shrinkage suppression sheet 2 without removing the shrinkage suppression sheet 2.

As described above, according to this embodiment, the same effect as that of the first embodiment can be obtained.

[0021]

As is apparent from the above description of the embodiments, the present invention fills holes formed in both the substrate component sheet and the shrinkage suppression sheet with a conductive paste to form electrodes, and controls shrinkage thereof. After firing a multilayer sheet in which a plurality of substrate constituent sheets are sequentially laminated inside the sheet as the outermost layer,
By the method of removing the outermost layer shrinkage suppressing sheet and those columnar electrodes, it is possible to prevent the reaction between the glass component of the inner electrode portion in contact with the outermost layer of the substrate constituting sheet and the shrinkage suppressing sheet and the alumina of the composition of the shrinkage suppressing sheet. In addition, it is possible to realize an excellent method for manufacturing a multilayer ceramic substrate in which the formation of the insulating layer can be prevented and the wiring pattern of the outermost layer can be easily formed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing the order of steps in a method for manufacturing a multilayer ceramic substrate according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the order of steps in a method for manufacturing a multilayer ceramic substrate according to a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing the order of steps in a conventional method for manufacturing a multilayer ceramic substrate.

[Explanation of symbols]

 1 Substrate constituent sheet 2 Shrinkage suppression sheet 4 Conductor paste 6 Columnar electrode

Claims (4)

[Claims] 1. A conductor paste is embedded in holes formed in both a substrate constituent sheet and a shrinkage suppressing sheet to form an electrode, and the shrinkage suppressing sheet is used as an outermost layer, and a plurality of substrate constituent sheets are sequentially laminated therein. A method for manufacturing a multilayer ceramic substrate, comprising: firing the multilayer sheet, removing the outermost shrinkage suppressing sheet, and then removing the formed columnar electrodes so as to be aligned with the same surface of the substrate constituting sheet. 2. A conductor paste is embedded in holes formed in both the substrate constituent sheet and the shrinkage suppression sheet to form an electrode, and the shrinkage suppression sheet is used as an outermost layer, and a plurality of substrate constituent sheets are sequentially laminated therein. A method for manufacturing a multilayer ceramic substrate, comprising: firing the multilayer sheet and then removing the outermost shrinkage-restraining sheet and the columnar electrodes contained therein simultaneously on the same surface of the substrate-constituting sheet. 3. The shrinkage control sheet has a sintering temperature higher than that of the substrate constituent sheet, and is sintered at a temperature within a range of a sintering temperature of the shrinkage suppressing sheet and a sintering temperature of the substrate constituent sheet. 2. The method for manufacturing a multilayer ceramic substrate according to 2. 4. The conductor paste according to claim 1, which is selected from the group consisting of copper oxide, silver, an alloy of silver and palladium, an alloy of silver and platinum, and copper. A method for manufacturing the described multilayer ceramic substrate.