JPH05183270A - Manufacture of ceramic multilayer board - Google Patents

Abstract

PURPOSE:To prevent imperfect electric continuity and high resistivity of a through hole in a ceramic multilayer board, by improving the positioning precision of a green sheet in each process. CONSTITUTION:Guide pins 3, 3a, 3b of a sheet fixing jig 2 are inserted into a plurality of postioning holes H1-H12 bored in the peripheral part of a green sheet 1, thereby fixing said sheet 1. In this fixing state, a hole 4a for forming a through hole is formed, a through hole 4 and a conductor circuit pattern 5 are printed, and the green sheet 1 is laminated. When each of these processes is performed, the combination of the positioning holes H1-H12 into which the guide pins 3, 3a, 3b are inserted is changed for each process.

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 ceramic multilayer substrate.

[0002]

2. Description of the Related Art In a conventional method for manufacturing a ceramic multi-layer substrate, positioning holes having an inner diameter of several mm are preliminarily provided at four corners of a green sheet, and guide pins provided on a sheet fixing jig are provided in the respective positioning holes. The green sheet is fixed on the jig by inserting the. Then, the steps of forming the holes for forming the through holes, printing the through holes and the conductor circuit pattern, and stacking the green sheets are performed with the green sheets thus fixed. The same positioning hole is usually used to fix the green sheet in each of the above steps.

[0003]

However, in the conventional method, since the inner diameter of the positioning hole and the diameter of the guide pin are substantially equal to each other and there is almost no clearance between them, the green sheet is attached to the jig. Also, there is a drawback that the positioning hole is deformed or expanded each time the removal is repeated. As a result, in the final step of stacking the green sheets, a positional deviation of about several tens of μm occurs between the green sheet layers in a direction orthogonal to the stacking direction, which causes defective conduction of through holes and increased resistance. Therefore, it has not been possible to sufficiently achieve the multi-layering and the high densification which have been recently desired for the ceramic multi-layer substrate.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the accuracy of positioning the green sheet in each process to reliably prevent defective conduction and increase in resistance of through holes. Another object of the present invention is to provide a method for manufacturing a ceramic multilayer substrate that can be manufactured.

[0005]

In order to solve the above problems, according to the present invention, a guide pin of a sheet fixing jig is inserted through a plurality of positioning holes transparently provided on the periphery of a green sheet, In the method for manufacturing a ceramic multilayer substrate, which comprises forming a through hole, forming a through hole and a conductor circuit pattern, and laminating a green sheet with the green sheet fixed, a positioning hole through which the guide pin is inserted. The combination of is changed for each of the above steps.

[0006]

According to the present method of changing the combination of the positioning holes for each process, even if the positioning holes are deformed or expanded by attaching and detaching the green sheet,
In the next process, a combination of positioning holes different from that in the previous process is selected, so that the positioning accuracy does not deteriorate in the subsequent process. Therefore, the green sheets can be stacked with high accuracy, and the conduction failure of the through hole and the increase in resistance can be reliably prevented. This is extremely suitable for increasing the number of layers and increasing the density of the ceramic multilayer substrate. A printing method is desirable as a method of forming the through hole and the conductor circuit pattern.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a method of manufacturing an aluminum nitride multilayer substrate having through holes will be described in detail with reference to the drawings.

In this example, aluminum nitride powder having an average particle size of 1.7 μm (a mixture of aluminum nitride powder made by Toyo Aluminum and aluminum nitride powder made by Tokuyama Soda) was used.
15.% by weight yttrium oxide, 3% by weight manganese dioxide, 9.6% by weight binder, 2% by weight plasticizer, 0.5% by weight dispersant, 14.3% by weight toluene and 16.3% ethanol. 7 wt% was added and they were mixed to form a slurry. This slurry was formed into a green sheet 1 having a thickness of 0.5 mm by the doctor blade method, and then the green sheet 1 was cut into a square shape of 80 mm × 80 mm.

As shown in FIG. 1, a total of 12 positioning holes H1 to H12 having a circular cross section and an inner diameter of 3 mm are formed in the periphery of the green sheet 1 at equal intervals. Further, the green sheet 1 is provided with through-hole forming holes 4
A was formed, the through holes 4 and the conductor circuit patterns 5 were printed, and the green sheets 1 were laminated. Each of the above steps will be described in detail below.

In the step of forming the through-hole forming holes 4a in the green sheet 1, the positioning of the green sheet 1 is performed with reference to the positioning holes H1, H4, H7 and H10 provided at the four corners of the green sheet 1. .. That is, in this step, as shown in FIG. 1, each of the positioning holes H1 and H1
A sheet fixing jig 2 in which four guide pins 3 are vertically formed at positions corresponding to 4, H7 and H10 was used. Each guide pin 3 has a circular cross section, and its diameter is set to be substantially the same as that of the positioning holes H1, H4, H7 and H10. Further, the tip of each guide pin 3 is processed into a shape without corners so as not to damage the green sheet 1.
Then, by inserting the guide pin 3 into the positioning holes H1, H4, H7, and H10, the green sheet 1 is moved to the jig 2.
A plurality of through-hole forming holes 4a were formed in the green sheet 1 by being fixed on the green sheet 1 by a conventional method such as drilling.

In the step of forming the through hole 4 and the conductor circuit pattern 5, the positioning holes H1 used in the previous step,
Positioning holes H5, H6, which are different from H4, H7, H10,
The green sheet 1 was positioned on the basis of H11 and H12. That is, as shown by the chain double-dashed line in FIG. 1, in this step, a sheet fixing jig in which four guide pins 3a are formed upright at positions corresponding to the positioning holes H5, H6, H11, H12. It was used. The cross-sectional shape and diameter of each guide pin 3a are the same as those of the jig 2 used in the process of forming the through hole forming hole 4a. Then, the positioning holes H5, H6,
The green sheet 1 was fixed on the jig by inserting the guide pins 3a into H11 and H12, and a highly viscous paste containing tungsten was screen-printed. As a result, the paste was filled in the through-hole forming holes 4a, and a desired conductor circuit pattern 5 was formed on the surface of the green sheet 1.

In the step of stacking the green sheets 1, the positioning holes H2, H3, and
The green sheet 1 was positioned on the basis of H8 and H9. That is, as shown by the chain double-dashed line in FIG. 1, in this step, a sheet fixing jig in which four guide pins 3b are formed upright at positions corresponding to the positioning holes H2, H3, H8, and H9. It was used. The cross-sectional shape and diameter of each guide pin 3b are the same as those of the jig 2 used in the step of forming the through hole forming hole 4a. Then, the positioning holes H2, H3, H8
, H9 to fix the plurality of green sheets 1 (4 sheets in this embodiment) on the jig by inserting the guide pins 3b, and the green sheets 1 are pressure-bonded by the laminating device (see FIG. 2). ..

After the laminated green sheets 1 are dried, they are dried at 1560 ° C. to 1600 ° C. in a non-oxidizing atmosphere.
Degreasing was performed by calcination for 10 hours. Then, according to a conventional method, firing was performed at 1850 ° C. to 1900 ° C. for 5 hours in an inert gas atmosphere to obtain a desired aluminum nitride multilayer substrate having through holes 4. The positioning holes H1 to H12 on the periphery of the green sheet 1 are removed by cutting the outer peripheral portion after the laminating step.

In order to evaluate the characteristics of the multilayer substrate obtained by the above method, the maximum positional deviation amount (μm) of each layer of the green sheet 1 when the green sheet 1 was laminated was measured. In addition, the occurrence of conduction failure in the through hole 4 and the sheet resistance (mΩ / □) of the multilayer substrate were also measured. Table 1 shows the results.

Further, in the comparative example with respect to this embodiment, the four corners of the green sheet 1, that is, H1, H4, H7 shown in FIG.
Positioning holes were provided only in the H10 part. Then, these positioning holes were always used to perform positioning when forming through-hole forming holes, forming through-holes and conductor circuit patterns, and stacking green sheets. Other conditions and methods were in accordance with the above examples. Table 1 also shows the results of the above measurements performed on this substrate.

[0016]

[Table 1]

As is clear from Table 1, the maximum positional deviation amount of each layer of the green sheet in the example is much smaller than that of the comparative example, and it is understood that the positioning accuracy of the green sheet of each layer in the laminating process was excellent. Further, in the examples, no conduction failure was observed in the through holes, and the sheet resistance of the multilayer substrate was also small.

According to this embodiment in which the combination of positioning holes is changed for each process, a combination of positioning holes different from the previous process can always be selected. Therefore, even if the positioning holes are deformed or widened by attaching and detaching the green sheets, the positioning accuracy at the time of stacking the green sheets does not deteriorate.

On the other hand, in the comparative example, not only the defective portion of conduction was recognized in the through hole, but also the sheet resistance of the multilayer substrate was larger than that of the example. In the comparative example in which the same combination of positioning holes was always used in each step, the positioning holes were deformed and expanded due to repeated attachment and detachment of the green sheet. This is considered to be the factor that brought about the above results.

The present invention is not limited to the above embodiment, but can be modified as follows. For example, (a) The positioning holes H1 to H12 may have an elliptical cross section or a polygonal cross section in addition to the circular cross section. (B) Further, the sectional shape of the positioning holes H1 to H12 and the sectional shape of the guide pins 3, 3a, 3b do not necessarily have to be the same. That is, like the sheet fixing jig 6 of the other example 1 shown in FIG. 3, the shape of the guide pin 7 may be a semi-circular cross section having a radius substantially the same as the positioning hole Ha. In this case, the arc surface of the guide pin 7 is arranged toward the center of the green sheet 1.

Further, as in the sheet fixing jig 8 of another example 2 shown in FIG. 4, the guide pin 9 may be tapered by cutting off the side corresponding to the corner of the green sheet 1. In that case, the diameter of the base end portion of the guide pin 9 is determined by the positioning hole Hb.
Of the positioning hole Hb is set to be substantially the same as the inner diameter of the positioning hole Hb.

The advantages of the first and second examples are that the green sheet 1 can be easily attached and detached, and the positioning holes Ha and Hb are less likely to be deformed or expanded. (C) Furthermore, the positioning holes H1 to H12 do not necessarily have to be provided at equal intervals as in the above embodiment. Further, the number of the guide pins 3, 3a, 3b of the sheet fixing jig 2 may be changed appropriately. (D) In addition, the positioning holes H1 to H1 used once
Even if it is 2, Ha or Hb, it may be reused unless it is a step immediately after its use. According to this method, the positioning holes H1 to H12, which are transparently provided on the green sheet 1,
Not only does the total number of Ha and Hb need to be small, but the positioning holes can be easily removed in the subsequent process.

[0023]

As described above in detail, according to the method for manufacturing a ceramic multilayer substrate of the present invention, the positioning accuracy of the green sheet in each step is improved, so that the conduction failure of through holes and the increase in resistance are surely achieved. It has an excellent effect of being prevented. In addition, it is possible to increase the number of layers and the density of the substrate, which has been desired in recent years for ceramic multilayer substrates.

[Brief description of drawings]

FIG. 1 is a perspective view showing a green sheet and a sheet fixing jig used in this embodiment.

FIG. 2 is a cross-sectional view showing stacked green sheets.

FIG. 3 is an enlarged perspective view showing a guide pin of another example 1.

FIG. 4 is an enlarged perspective view showing a guide pin of Modification 2.

[Explanation of symbols]

1 green sheet, 2 (for sheet fixing) jig, 3,
3a, 3b guide pin, 4 through hole, 4a through hole forming hole, 5 conductor circuit pattern, H1 to H
12 Positioning hole.

Claims (1)

[Claims] 1. A guide pin (3, 3a, 3b) of a sheet fixing jig (2) is inserted through a plurality of positioning holes (H1 to H12) provided transparently on the periphery of a green sheet (1). , A ceramic multi-layer in which the green sheet (1) is fixed and the through hole forming holes (4a) are formed, the through holes (4) and the conductor circuit pattern (5) are formed, and the green sheet (1) is laminated. In the method for manufacturing a substrate, the combination of positioning holes (H1 to H12) into which the guide pins (3, 3a, 3b) are inserted is changed for each of the steps, and a method for manufacturing a ceramic multilayer substrate. ..