JPH11233690A - Manufacturing multilayer ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer ceramic substrate, whereby the area of a dummy zone ensured in a ceramic green sheet laminate is reduced to greatly increase the no. of ceramic substrate-forming parts taken from a ceramic green sheet laminate, thereby improving the productivity of the ceramic substrate. SOLUTION: This substrate comprises the steps of cutting a laminate of a plurality of laminated ceramic green sheets into pieces composed of parts 23 for forming multilayer ceramic substrates and parts 24 of dummy zones 24, chamfering the outside edge of the lower face of each of the plurality of cut pieces, and cutting the boundary between the dummy zone 24 and parts 23 for forming multilayer ceramic substrates from the opposite face to the chamfered face of each cut pieces, using a single-blade cutter 25 to remove the dummy zones 24 from the parts 23 for forming multilayer ceramic substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a multilayer ceramic substrate for an IC package.

[0002]

2. Description of the Related Art FIG. 7 is a flowchart showing a method of manufacturing a multilayer ceramic substrate for an IC package such as a PGA (pin grid array). As shown in the flowchart of FIG. 7, in the multilayer ceramic substrate for PGA, a plurality of ceramic green sheets on which a conductor pattern is formed are laminated (step 1), and this laminate is separated into individual unfired ceramic laminates. Each piece is cut into pieces (step 2), and the edges of the four sides of each piece are cut obliquely and chamfered (step 3, see reference numeral 6 in FIG. 8).
After each step such as cutting corners (step 4; see reference numeral 7 in FIG. 8), baking step (step 5) brazing and plating of lead pins (not shown)
After that, it is completed. As described above, in PGA or the like, before firing, a laminate of one ceramic green sheet is cut into a plurality of pieces to make a single product.

In the conventional method of manufacturing a multilayer ceramic substrate, in the above-mentioned cutting (step 2), a portion from a single ceramic green sheet laminate 10 to a multilayer ceramic substrate as shown in FIG. When cutting to take out (single piece), between each part 11 which becomes a multilayer ceramic substrate, m,
The cutting is performed after a certain interval (dummy band) as shown in FIG. Thus, each part 1
The reason why the dummy band is interposed between the 1s is as follows. First, if the dummy bands m and n are not interposed between the portions 11 to be the multilayer ceramic substrate, the plated lead of the conductor pattern of each portion 11 will enter the adjacent portion 11. Because
To prevent this, it is necessary to interpose a dummy band. Second, it is necessary to interpose a dummy band in order to adjust the dimensions of each portion 11 before firing.

[0004] Conventionally, dummy bands m and n interposed between the respective portions 11 to be a multilayer ceramic substrate are formed as follows.
The width (the area is large) was set so that the width was 3 mm or more. The reason is that
The part indicated by C in FIG. 10 is cut, and then D in FIG.
Considering the case where a portion indicated by is cut, dummy bands m, n
When the width is as large as 3 mm or more, FIG.
As shown in FIG. 10A, not only the portion C but also the portion D can be accurately cut in the vertical direction in the figure. However, when the width of the dummy bands m and n is smaller than 3 mm, the portion shown in FIG. As shown in b), even if the first point C can be cut accurately, the next cutting at the point D results in "escape of the cutting blade". Does not enter, making it impossible to cut accurately. For this purpose, at least 3
It was necessary to secure dummy bands m and n having a width (large area) of not less than mm width.

[0005]

However, how many portions 11 to become a multilayer ceramic substrate can be obtained from one ceramic green sheet laminate 10 (how many of the portions 11 can be taken out in the sheet). Is a problem that greatly affects the productivity of the multilayer ceramic substrate.
If the dummy bands m and n can be formed narrower than in the related art, the number of the portions 11 that can be obtained from the ceramic green sheet laminate 10 can be greatly increased, and the productivity of the multilayer ceramic substrate can be improved.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and the size of a dummy band to be secured around a portion to be a multi-layer ceramic substrate is reduced so that one ceramic It is an object of the present invention to provide a method for manufacturing a multilayer ceramic substrate, which can greatly increase the number of ceramic substrate portions that can be obtained from a green sheet laminate, thereby greatly improving the productivity of the multilayer ceramic substrate.

[0007]

[Detailed description of the invention]

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, first, a laminate 21 of one ceramic green sheet is cut along dashed lines A and B in the figure, and a total of 12 pieces 2 as shown in FIG.
Divide into two. As shown in FIGS. 2A and 2B, each of the pieces 22 includes a portion 23 to be a multilayer ceramic substrate and a dummy band 24 around the portion 23 (a portion indicated by oblique lines in FIG. 2). However, the width of the dummy band 24 is smaller than 3 mm, which is very narrow as compared with the conventional band (see FIG. 9).

Next, for each piece 22, this dummy band 2
The step of cutting and removing 4 will be described. In the present embodiment, the dummy band 24 of each piece 22 obtained by cutting and dividing the ceramic green sheet laminate 21 is much narrower than the conventional one. If it is left as it is, there is a problem that "escape of the cutting blade" (see FIG. 10B) occurs and it is not possible to cut accurately. Therefore, as shown in FIG. 3, the inventor has decided to cut the dummy band 24 from the portion 23 using a single-edged blade 25 (a blade having an inclined cutting surface). As a result, it was confirmed that the above-mentioned "escape" was prevented, and the blade 25 was accurately inserted in the vertical direction in the figure.

However, as a next problem, when cutting is performed with the single-edged blade 25 (see FIG. 3 (a)), the outgoing portion of the single-edged blade 25 may have a fracture surface 23a due to a preceding crack at the time of cutting. (See FIG. 3B), and it was found that the yield was reduced. Therefore, before cutting the dummy band 24, the inventor of the present invention has shown the outer peripheral edge of the portion of each piece 22 on the exit side of the single-edged blade 25 (the lower part of each piece 22 in the drawing). 4 (a)
Chamfering was performed using a blade as shown in (b). As shown in FIG. 5, the chamfer is formed so as to have an inclination angle of about 45 degrees with respect to the horizontal direction of FIG.
It was done to include some of them. Thereby, each piece 22
A chamfered portion 26 was formed at the lower edge of the.

After the chamfered portion 26 was formed, the dummy band 24 was cut and removed using the single-edged blade 25 (see FIGS. 6A and 6B). In this case, FIG.
No fracture surface 23a as shown in FIG.
The dummy band 24 can be cut and removed with high precision (see FIG. 6C).

As described above, in the present embodiment, when taking out a plurality of portions 23 to be a plurality of multilayer ceramic substrates from one ceramic green sheet laminate 21, first,
The laminate 21 is cut and divided so as to include the dummy band 24. When cutting and removing the dummy band 24 from the portion 23 to be the multi-layer ceramic substrate, first, a chamfered portion 26 is formed at the outer peripheral edge of the piece 22 on the exit side when the dummy band 24 is cut. After that, the dummy band 24 is cut and removed by the single-edged blade 25. Therefore, the dummy belt 24
Can be cut / removed with high precision and high accuracy only when the dummy band has a very small width of 3 mm or less. Therefore, according to the present embodiment, one ceramic green sheet laminate 21
Thus, the number of portions 23 to be a multilayer ceramic substrate can be greatly increased compared to the related art, and the productivity of the multilayer ceramic substrate can be greatly improved.

In the experiment of the present inventor, only six pieces were conventionally obtained from a ceramic green sheet for a 168-pin IC package, but according to the present embodiment, nine pieces can be obtained. became. Also, the 296-pin O
From ceramic green sheets for IC packages,
Conventionally, only 12 pieces could be taken, but according to the present embodiment, 15 pieces can be taken.

[0014]

As described above, according to the present invention, when taking out a portion to be a plurality of multilayer ceramic substrates from one ceramic green sheet laminate, first, the laminate including a dummy band is taken out. Is cut and split. Then, when cutting and removing the dummy band from the portion to be the multilayer ceramic substrate, first, the delivery side when cutting the dummy band in each piece including the portion to be the multilayer ceramic substrate and the dummy band. A chamfered portion is formed on the outer peripheral edge of the. Thereafter, the dummy band is cut with a single-edged knife. According to the above method, even when the dummy band in the laminated body of one ceramic green sheet has only a small width of 3 mm or less, finally, only the dummy band is precisely and accurately formed by the multilayer ceramic. It can be cut and removed from the portion that will become the substrate. Therefore, according to the present invention, the number of dummy bands to be secured in one ceramic green sheet laminate can be significantly reduced as compared with the related art, and a multilayer ceramic substrate obtained from one ceramic green sheet laminate can be obtained. It is possible to improve the productivity of the multilayer ceramic substrate by greatly increasing the number of portions to be formed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a ceramic green sheet laminate used in a method for manufacturing a multilayer ceramic substrate according to an embodiment of the present invention.

FIGS. 2A and 2B show respective pieces cut from a ceramic green sheet laminate in the present embodiment, wherein FIG. 2A is a plan view and FIG. 2B is a side view.

FIG. 3 is a diagram for explaining a process of cutting and removing a dummy band of each piece with a single-edged blade in the present embodiment, and a problem occurring at that time.

FIG. 4 is a view for explaining a method for forming a chamfered portion on an outer peripheral edge of a single-edged blade before cutting and removing a dummy band of each piece in the present embodiment.

FIG. 5 is a side view showing a state in which a chamfered portion is formed on an outer peripheral edge of each piece at a lower portion in the drawing in the present embodiment.

FIG. 6 is a view showing an operation when the dummy band is cut / removed with a single-edged blade after a chamfered portion is formed on an outer peripheral edge portion shown below in the embodiment.

FIG. 7 is a flowchart showing a conventional method for manufacturing a multilayer ceramic substrate for an IC package.

FIG. 8 is a perspective view showing an example of a conventional multilayer ceramic substrate.

FIG. 9 is a plan view showing a conventional ceramic green sheet laminate and a dummy band secured therein.

FIG. 10 is a diagram for explaining a dummy band cutting operation according to a conventional method and a problem thereof.

[Explanation of symbols]

 Reference Signs List 21 laminated body of ceramic green sheets 22 piece 23 part to be a multilayer ceramic substrate 23a fractured surface 24 dummy band 25 single-edged knife 26 chamfer

Claims (1)

[Claims] 1. A method of manufacturing a multilayer ceramic substrate for an IC package, comprising: forming a laminate of a plurality of ceramic green sheets on a portion to be a multilayer ceramic substrate; Cutting and dividing into each piece including; and, for each of the cut and divided pieces, chamfering the outer peripheral end of one surface thereof, including the dummy band and other portions. For each of the pieces, in order to remove the dummy band from the portion to become the multilayer ceramic substrate, between the dummy band and the portion to become the multilayer ceramic substrate, with a single-edged blade,
Cutting from the surface opposite to the chamfered surface toward the chamfered surface.