JPH06144937A - Production of ceramic substrate - Google Patents

Abstract

PURPOSE:To provide the production method of the ceramic substrate capable of preventing generation of crack near a square hole and small in dimensional error. CONSTITUTION:This is the production method of the ceramic substrate having the square hole 1. The square hole 1 whose corner part 11 is a non right-angled shape is pierced on the green sheet for forming the ceramic substrate. Unsintered green sheet are set on the up side and under side of the green sheet and they are hot-press-bonded and burned. After that, the unsintered green sheets are removed. Adjacent two sides forming the square hole 1 is continuous with a interposing line 113 which is a curved line such as an arc or a straight line. The corner part 11 is the arc of >=0.5mm radius preferably. And, the corner part 11 may be the pushed-out shape by >=0.5mm from the crossing point at which the adjacent two lines are crossed in the square hole 1.

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 substrate having a square hole into which a lead wire or the like of an electronic component is inserted.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS.
As shown in FIG. 0, there is one in which a square hole 2 for inserting a lead wire or the like of an electronic component is formed. In manufacturing the ceramics substrate 99, first, the square holes 2 are formed in the green sheet for forming the ceramics substrate. Then, the green sheet is fired. As a result, the ceramic substrate 99 is obtained.

[0003]

However, according to the above-described manufacturing method, when the green sheet is fired, the green sheet shrinks, and the dimension of the ceramic substrate varies by 0.3% or more. Therefore, when inserting the lead wire of the electronic component into the square hole 2, there is a possibility that an insertion failure may occur.

Further, during the above-mentioned firing, as shown in FIG. 11, the crack 2 is formed in the corner portion 20 of the square hole 2 due to the firing.
9 may occur. In view of such a problem, the present invention can prevent the occurrence of cracks near the square hole,
Moreover, it is an object of the present invention to provide a method for manufacturing a ceramic substrate with a small dimensional error.

[0005]

The present invention relates to a method of manufacturing a ceramic substrate having a square hole, wherein a green sheet for forming the ceramic substrate and an unsintered body which does not sinter at the sintering temperature of the green sheet. A step of preparing a green sheet, B step of punching a square hole having a non-rectangular shape in the corner of the green sheet, and placing the green sheet above and below the green sheet, A ceramic substrate comprising: a C step of thermocompression-bonding to obtain a laminated body; and a D step of firing the laminated body at a sintering temperature of the green sheet and thereafter removing the unsintered green sheet. There is a manufacturing method.

What is most noticeable in the present invention is that the corners of the square holes have a non-rectangular shape, and when the green sheet having the square holes is fired, unsintered green sheets are placed above and below it. Is what you are doing. The corner is the corner of a square hole. Two adjacent sides forming a square hole are continuous via an intervening line which is a curved line such as an arc or a straight line.

The corners are preferably arcuate with a radius of 0.5 mm or more. At this time, the intervening wire has an arc shape with a radius of 0.5 mm or more. If it is less than 0.5 mm, cracks may occur.

The corner portion is 0.5 mm from the intersection where the extension lines of two adjacent sides intersect in the square hole.
The extruded shape is preferable. At this time, the intervening line becomes a straight line. Then, the corner portion has a triangular shape. If it is less than 0.5 mm, cracks may occur. Further, it is preferable to coat the inner wall of the square hole with Ag metallization. As a result, the lead wire and the inside of the square hole can be firmly connected by soldering or the like.

The unsintered green sheet is not fired or deformed during thermocompression bonding and firing in the step C. Further, the unsintered green sheet does not prevent evaporation of the binder contained in the green sheet when placed on the green sheet. As the unsintered green sheet, a mixture of a sheet material such as alumina, zirconia, and mullite and a binder is used.

The green sheet is made of CaO-Al ₂ O _3-.
A solvent, a binder, a plasticizer, etc. are kneaded with a ceramic substrate material such as SiO ₂ —B ₂ O ₃ glass and alumina,
It is formed into a sheet. 1 green sheet
It is preferably a low temperature firing substrate material that can be sintered at 000 ° C or lower.

When unsintered green sheets are placed above and below the green sheets, the number of green sheets is one or two or more. Further, a circuit pattern such as an outer layer circuit or an inner layer circuit can be formed by printing on the surface of the green sheet.

[0012]

In the present invention, the corner portion of the square hole has a non-rectangular shape. Therefore, when firing the green sheet, stress does not concentrate on the corners of the square holes. Therefore, cracks do not occur near the square holes.

When the green sheets are stacked, pressed and fired, unsintered green sheets are placed on the uppermost and lowermost surfaces thereof. The green sheets are C and D
Does not deform during thermocompression bonding or firing in the process. Therefore, the ceramic substrate has few dimensional errors. Moreover, the dimensional error of the square hole formed in the ceramic substrate is small. Therefore, the lead wire of the electronic component can be reliably inserted into the square hole.

The unsintered green sheet is in a state in which the binder therein is thermally decomposed during firing in the step D and is very fragile and easily peeled off. Therefore, the unsintered green sheet can be easily removed by an extremely simple operation such as tapping the ceramic substrate lightly and rubbing it with a brush. According to the present invention, it is possible to provide a method for manufacturing a ceramic substrate which can prevent the occurrence of cracks in the vicinity of a square hole and have few dimensional errors.

[0015]

【Example】

Example 1 An example according to the present invention will be described with reference to FIGS. In this example, the ceramic substrates 91 to 94
Form a laminated multi-layer substrate 9 as shown in FIG. As shown in FIGS. 1 and 2, the ceramic substrates 91 to 94 are provided with a square hole 1 having a corner portion 11 having a non-rectangular shape. The square hole 1 is a through via hole.

The corner portion 11 has an arc shape with a radius R0.5 mm. The corner portion 11 is a corner portion of the square hole 1. Two adjacent sides 101, 10 forming the square hole 1
2, sides 102, 103, sides 103, 104, and side 10
4, 101 are continuous through intervening lines 113, respectively. The intervening line 113 has an arc shape with a radius R0.5 mm.

All four sides 101 to 104 of the square hole 1 have the same length. The distance S between the two sides 101, 103 and the sides 102, 104 of the square hole 1 facing each other is 3 m.
m. As shown in FIG. 3, the square hole 1 is formed by penetrating the ceramic substrates 91 to 94.

A method of manufacturing the ceramic substrate of this example will be described. In the process A, as shown in FIG. 4, the green sheet 71 for forming the ceramic substrates 91 to 94 is formed.
˜74, and unsintered green sheets 61 and 69 that are not sintered at the sintering temperature of the green sheets are prepared. The green sheets 71 to 74 are low temperature firing substrate materials that are sintered at 1000 ° C. or lower.

In producing the green sheets 71 to 74, first, CaO--Al ₂ O ₃ --SiO _2-
A solvent, a binder, and a plasticizer are added to a mixed powder of a ceramic substrate material composed of 60% by weight of B ₂ O ₃ glass (hereinafter referred to as “%”) and 40% of alumina, and the mixture is kneaded.
Make a slurry. Then, using a conventional doctor blade method, a green sheet having a thickness of 0.3 mm is produced using the above slurry.

In producing the green sheets 61 and 69, the alumina powder is mixed with a binder to form a paste. Then, using a conventional doctor blade method, using the above paste, the thickness of
A 2 mm green green sheet is prepared. The unsintered green sheets 61 and 69 do not undergo deformation such as expansion and contraction due to thermocompression bonding in the laminating process and heating in the heating process. The unsintered green sheet does not prevent evaporation of the binder contained in the green sheet when laminated on the green sheet.

Next, in step B, a square hole 1 having a non-rectangular corner portion 11 is formed in each of the green sheets 71 to 74. Next, in step C, as shown in FIG. 4, the unsintered green sheet 69 and green sheet 7 are formed.
4, 73, 72, 71, unsintered green sheet 61,
Layers are sequentially stacked from the bottom, aligned, and thermocompression bonded to obtain a laminated plate 98. The conditions for thermocompression bonding are a temperature of 100 ° C., a pressing force of the laminated plate 98 of 50 kg / cm ² , and 20 seconds.

Next, in the step D, the laminated plate 98 is heated to a maximum temperature of 900 ° C. at a temperature at which the green sheet is sintered.
Baking is performed under the condition that the holding time is 20 minutes. Accordingly, the green sheets 71 to 74 are sintered and the ceramic substrates 91 to 74 are sintered.
It becomes 94. After that, unsintered green sheets 61, 69
Are removed with a brush. Further, the alumina powder remaining on the ceramic substrate is removed by ultrasonic cleaning. As a result, the multilayer substrate 9 shown in FIGS.
Is obtained.

Next, the function and effect of this example will be described.
In this example, the corner portion 11 of the square hole 1 has a non-rectangular shape. Therefore, when firing the green sheets 71 to 74, stress is not concentrated on the corner portion 11 of the square hole 1. Therefore, no crack is generated in the vicinity of the square hole 1.

Further, the green sheets 71 to 74 are laminated,
When press-bonding and firing, unsintered green sheets 61, 69 are placed on the uppermost and lowermost surfaces thereof. The unsintered green sheets 61 and 69 are thermocompression bonded in the C and D steps,
Does not deform when fired. Therefore, the ceramic substrate 9
1 to 94 have few dimensional errors. Further, the dimensional error of the square hole 1 formed in the ceramic substrates 91 to 94 is small.
Therefore, the lead wire of the electronic component can be surely inserted into the square hole.

The unsintered green sheets 61, 69
In the case of firing in step D, the binder therein is thermally decomposed and becomes very brittle and easily peeled off. Therefore, the ceramic substrate 9-94 can be lightly struck and rubbed with a brush.
It is possible to easily remove the unsintered green sheets 61 and 69 from 1 to 94.

Embodiment 2 In this embodiment, as shown in FIGS. 5 and 6, the corner portion 12 is extruded from an intersection point 123 where extension lines 121 and 122 of two adjacent sides in the square hole 1 intersect. L
The shape is extruded by 0.5 mm.

At this time, the intervening lines 114 that are respectively interposed on the two adjacent sides of the square hole 1 are straight lines. Then, the corner portion 12 has a triangular shape. Others are the same as in the first embodiment. Also in this example, the same effect as that of the first embodiment can be obtained.

Example 3 In this example, as shown in Table 1, with respect to the ceramic substrates of Examples 1 and 2, the distance S between the two sides of the square hole facing each other, the radius R of the intervening wire and the extrusion length L are shown. Were produced in various ways (E1 to E10) (FIG. 1,
2, 5, 6).

Example 4 As shown in FIG. 7, the ceramic substrate of this example is formed by forming square holes 1 in ceramic substrates 91 and 92 (E11 to E20). The square hole 1 has a cavity shape, and the upper surface 931 of the ceramic substrate 93 becomes the bottom surface of the square hole 1. Others are the above samples E1 to E10
Is the same as.

Example 5 As shown in FIG. 8, the ceramic substrate of this example is one in which the periphery of the square hole 1 of each of the samples E1 to E10 is covered with an Ag-based metallization 5 (E21 to E30).

Comparative Example 1 As shown in Table 2, the ceramic substrate of this example is the same as the ceramic substrates of Examples 1 and 2 except that the distance S between two sides of the square hole, the radius R of the intervening line and the extrusion length. (C1 to C6) (FIG. 1,
2, 5, 6).

Comparative Example 2 The ceramic substrates of this example are ceramic substrates 91, 9
2 is formed by forming a square hole 1 (C7-
C12) (see FIG. 7). The bottom surface of the square hole 1 is the top surface 931 of the ceramic substrate 93. Others are the above sample C1
~ C6 is the same.

Comparative Example 3 The ceramic substrate of this example is one in which the periphery of the square hole 1 of the samples C1 to C6 is covered with an Ag-based metallization 5 (C13 to C18) (see FIG. 8).

Comparative Example 4 The ceramic substrate of this example was manufactured without stacking the green sheets by laminating, pressure bonding and firing the green sheets (C19 to C48). Others are the same as those of the ceramic substrates (E1 to E30) manufactured according to the above-mentioned Examples 3 to 5.

Comparative Example 5 In manufacturing the ceramic substrate of this example, when the green sheets were stacked, pressed and fired, the green sheets were not used (C49 to C66). Others are the same as those of the ceramic substrates (C1 to C18) produced in Comparative Examples 1 to 3 above.

Experimental Example In this example, the above-mentioned Examples 3 to 5 and Comparative Example 1 were used.
~ Ceramic substrate according to Comparative Example 5 (E1 to E30,
C1 to C66) were prepared for each 10 sheets, and the presence or absence of cracks in the vicinity of the square hole and the dimensional error of the distance S between two sides of the square hole were measured. The results are shown in Table 3. Further, the samples used in the above experiment are the samples E1 to E30 relating to the present invention and the samples C1 to C66 of the comparative example.
Although these conditions have been described above, just in case, they are summarized and shown in Table 4.

As can be seen from Table 3, samples E1 to E3
The ceramic substrates of No. 0 and Samples C1 to C18 had a dimensional error of 0.12% or less and were excellent in dimensional accuracy. However, cracks were observed in Samples C1 to C18. On the other hand, no cracks were found in the ceramic substrates E1 to E30 and C19 to C48. However, the samples C19 to C48 have a dimensional error of 0.34 to 0.
It was 45%, which was inferior in dimensional accuracy.

Further, in the samples C49 to C66, cracks were observed and the dimensional accuracy of the ceramic substrate was poor. As is known from the above, the ceramic substrates of Examples 3 to 5 according to the present invention have excellent dimensional accuracy,
And there are no cracks.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[Brief description of drawings]

FIG. 1 is a plan view of a ceramic substrate of Example 1.

FIG. 2 is an enlarged plan view of a corner portion of the ceramic substrate of Example 1;

3 is a sectional view taken along the line AA of FIG.

FIG. 4 is an explanatory view showing a method for manufacturing a ceramic substrate of Example 1.

FIG. 5 is a plan view of a ceramic substrate of Example 2.

FIG. 6 is an enlarged plan view of the corner portion of the ceramic substrate of Example 2;

FIG. 7 is a cross-sectional view of a ceramic substrate of Example 4.

FIG. 8 is a cross-sectional view of the ceramic substrate of Example 5.

FIG. 9 is a plan view of a conventional ceramic substrate.

FIG. 10 is a perspective view of a conventional ceramic substrate.

FIG. 11 is a plan view of a ceramic substrate showing the problems of the conventional example.

[Explanation of symbols]

 1. ． ． Square hole, 101-104. ． ． Edge, 11, 12. ． ． Corner part, 113, 114. ． ． Intervening line, 121, 122. ． ． Extension line, 123. ． ． Intersection, 5. ． ． Ag-based metallization, 61, 69. ． ． Unsintered green sheet, 71-74. ． ． Green sheet, 91-94. ． ． Ceramics substrate, 98. ． ． Laminate, R.S. ． ． The radius of the intervening line, L. ． ． Extrusion length of intervening wire,

Claims (3)

[Claims] 1. A method for manufacturing a ceramic substrate having a square hole, wherein a green sheet for forming the ceramic substrate and an unsintered green sheet which is not sintered at a sintering temperature of the green sheet are prepared. Step A, and Step B of forming a square hole having a non-rectangular corner in the green sheet, and placing the unsintered green sheet above and below the green sheet and stacking them by thermocompression bonding. A method of manufacturing a ceramic substrate, comprising: a step C for obtaining a body, and a step D for firing the laminate at the sintering temperature of the green sheet and thereafter removing the green sheet. 2. The method for manufacturing a ceramic substrate according to claim 1, wherein the corner portion has an arc shape with a radius of 0.5 mm or more. 3. The corner portion according to claim 1, wherein the corner portion is 0.5 from an intersection where two adjacent sides intersect in a square hole.
A method of manufacturing a ceramic substrate, which has a shape extruded by mm or more.