JP2729731B2 - Manufacturing method of ceramic multilayer substrate - Google Patents

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 for mounting an integrated circuit.

[0002]

2. Description of the Related Art In recent years, ceramic multilayer substrates for mounting integrated circuits have recently been reduced in size and density.
High precision with a dimensional error of ± 0.05% or less has been required. Conventionally, in manufacturing a ceramic multilayer substrate, first, a plurality of ceramic green sheets are subjected to via hole processing, printing of a conductor pattern, and the like.

Then, as shown in FIG. 9, the ceramic green sheets 71 to 74 are laminated to form a parallel flat plate 1.
The ceramic green sheet is pressed between the parallel flat plates 11 by pressing the ceramic green sheet. Next, the compressed ceramic green sheet is fired to obtain a ceramic multilayer substrate.

[0004]

However, the ceramic multi-layer substrate obtained by the above manufacturing method has a variation of ± 0.3% due to the variation in the elongation and the dimensional variation of the green sheet before lamination before firing and the variation in shrinkage during firing. There is a problem that there is a dimensional error exceeding, and the printing accuracy of the conductor pattern and the like thereafter deteriorates. The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a ceramic multi-layer substrate which has a small variation in elongation at the time of lamination and dimensional shrinkage at the time of firing and is excellent in dimensional accuracy.

[0005]

According to the present invention, there is provided an A step of preparing a ceramic green sheet and an unsintered green sheet that does not sinter at the sintering temperature of the ceramic green sheet; A step B in which the green sheet is placed on the green sheet to obtain a laminate, and a step C in which the laminate is pressed to obtain a press-bonded body while the elongation in the planar direction is suppressed to 0.05% or less. When,
A step of firing the pressed body at the sintering temperature of the ceramic green sheet; and a step of removing the unsintered green sheet from the pressed body to obtain a sintered ceramic substrate. To manufacture a ceramic multi-layer substrate.

The most remarkable point in the present invention is to produce a press-bonded body by the above-mentioned steps B and C, and to remove the unsintered green sheet after firing in the step D. In the step C, as a pressurizing method for suppressing the elongation to 0.05% or less, the laminate is housed in a rigid container having the same shape as the laminate, and the laminate is pressed by a parallel flat plate from above and below. There is a way to press.

The rigid container has the same internal dimensions as the planar shape of the laminate. The rigid container presses the laminate vertically with parallel plates when pressing the laminate, and at the same time, prevents the ceramic green sheet from stretching.
A ceramic multilayer substrate having excellent dimensional accuracy can be obtained.

As another pressing method, there is a method in which a film having a surface roughness of 0.4 to 0.75 μRa is interposed between the laminate and the parallel flat plate to perform pressing. This gives
A green sheet having a small elongation percentage and a high dimensional accuracy can be obtained. When the surface roughness is less than 0.4 μRa, there is a problem that the elongation percentage of the ceramic green sheet is increased. On the other hand, when it exceeds 0.75 μRa, there is a problem that the surface of the press-bonded body becomes rough.
Examples of the film include an organic material represented by polyester, paper, and the like.

As another pressing method in the step C, there is an isostatic pressing method in a liquid. The isotropic pressure pressing method is a method in which the above-mentioned laminate is put in a waterproof bag and sealed to form a sealed body, and the sealed body is immersed in a liquid and pressed. According to this method, pressure is uniformly applied to the laminate from all directions, so that the obtained crimped body has small elongation and small dimensional variations. It is preferable that the inside of the sealed body is in a vacuum state. This allows pressure from the liquid to be applied directly to the laminate.

[0010] The ceramic green sheet has a size of 10
It is preferably a low-temperature fired substrate material that sinters at a temperature of 00 ° C. or lower. As the green sheet, for example, an alumina material is used. Via holes and conductor patterns can be formed in advance on the ceramic substrate. The number of the ceramic green sheet and the ceramic substrate may be plural or one.

[0011]

According to the manufacturing method of the present invention, in the step C, the laminate is pressed to form a press-bonded body while the elongation in the planar direction is suppressed to 0.05% or less. for that reason,
Elongation rate and dimensional variation of the press-bonded body before firing are small. Therefore, even when the press-bonded body is subsequently heated and fired, the shrinkage in firing and the dimensional variation are small.

In the present invention, when the above-mentioned laminate is pressed to obtain a press-bonded body, the upper and lower sides thereof are sandwiched by unsintered green sheets, and the pressed-up body is directly heated for firing. Therefore, the dimensional error of the ceramic multilayer substrate obtained by firing is reduced to ± 0.05% or less (see Table 1), and the subsequent printing accuracy of the conductor pattern and the like is improved. ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the ceramic multilayer substrate excellent in the dimensional accuracy which the dispersion | variation of the elongation at the time of lamination | stacking and the dimensional shrinkage at the time of baking are small can be provided.

[0013]

Embodiment 1 An embodiment according to the present invention will be described with reference to FIGS. Ceramic multilayer substrate 9 manufactured according to this example
Are ceramic substrates 81 to 81 as shown in FIGS.
84 and a large number of via holes 5 formed in the ceramic substrate, and the via holes 5 are filled with a conductor.

Next, a method of manufacturing the ceramic multilayer substrate will be described with reference to FIGS. First, in step A, a ceramic green sheet and an unsintered green sheet that is not sintered at the sintering temperature of the ceramic green sheet are prepared. The ceramic green sheet is a low-temperature fired substrate material having a thickness of 0.3 mm.
The low-temperature fired substrate material is CaO—Al ₂ O ₃ ─SiO ₂
─60% by weight of B ₂ O ₃ based glass powder and 40 of alumina powder
A binder, a plasticizer, and a solvent are added to a mixed powder consisting of 100 wt% and kneaded to form a slurry, and the slurry is formed by a doctor blade method.

The unsintered green sheet is formed by molding an alumina material into a sheet having a thickness of 0.3 mm.
The alumina material is formed by using alumina powder in the same manner as the above ceramic green sheet. Next, each of the ceramic green sheet and the unsintered green sheet is cut into a 150 mm × 150 mm square shape. Next, a via hole 5 (see FIG. 6) is formed in the ceramic green sheet.

Next, in step B, as shown in FIG. 2, the ceramic green sheets 74, 73, 7
2, 71 are laminated in order from the bottom. Further, the unsintered green sheets 61 and 69 are placed on the front and back surfaces of the outermost ceramic green sheets 71 and 74 to obtain a laminate 90. Next, in the step C, as shown in FIG. 3, the laminated body is pressed while the elongation percentage in the planar direction is suppressed to 0.05% or less to obtain the press-bonded body 91.

As shown in FIG. 1, this crimped body 91 is placed in a rigid container 1 having the same shape as the laminated body 90.
And pressurized by the parallel plates 11 and 19 from above and below. The rigid container 1 has the same internal dimensions as the laminate 90. The inside of the rigid container 1 has the same shape as the laminate 90 and has a square shape of 150 mm × 150 mm. Pressing conditions are 50 kg / cm ² , 100
° C for 20 seconds. After the pressurization, the parallel flat plates 11 and 19 are removed, and the press-bonded body 91 is removed from the rigid container 1.

Next, in step D, the pressed body is fired at the sintering temperature of the ceramic green sheet. Thus, a sintered body 92 is obtained as shown in FIG. The sintered body 92 includes ceramic substrates 81 to 84 on which ceramic green sheets 71 to 74 are sintered, and unsintered green sheets 61 and 69. The firing conditions are air,
The maximum temperature is 900 ° C and the holding time is 20 minutes.

Next, in step E, as shown in FIG.
1, 69 are peeled by hand. Then, a trace amount of alumina powder remaining on the surface is completely removed by an ultrasonic cleaner in a solvent. Thus, the ceramic multilayer substrate 9 shown in FIG. 5 is obtained.

Next, the operation and effect of this embodiment will be described.
In the manufacturing method of the present example, in the step C, the laminate is pressed to form a press-bonded body while the elongation in the planar direction is suppressed to 0.05% or less. Therefore, the elongation and dimensional variation of the press-bonded body before firing are small. Therefore, even when the pressure-bonded body 91 is subsequently heated and fired, the shrinkage in firing and the dimensional variation are small.

In this embodiment, when the laminated body 90 is pressurized to obtain the press-bonded body 91, the upper and lower sides thereof are sandwiched between unsintered green sheets 61 and 69, and the pressed-down body 91 is directly used for firing. Heating. Therefore, the dimensional error of the ceramic multilayer substrate obtained by firing is reduced to ± 0.05% or less (see Table 1), and the subsequent printing accuracy of the conductor pattern and the like is improved.

The crimping body 91 presses the laminate 90 from above and below in a state where the laminate 90 is housed in the rigid container 1 having the same shape as the laminate 90. Therefore, the rigid container 1 prevents the ceramic green sheets 71 to 74 from expanding in the plane direction when the laminate 90 is pressed. Therefore, a ceramic multilayer substrate 9 having excellent dimensional accuracy can be obtained.

Embodiment 2 In this embodiment, as shown in FIG. 7, in the step C of the embodiment 1, the surface roughness between the laminate 90 and the parallel flat plates 11 and 19 is reduced to 0 without using a rigid container. The laminate 90 is pressurized with the films 21 and 29 of 0.5 μRa interposed therebetween to form a press-bonded body. After crimping, press the film 2
Strip 1 and 29. The films 21, 29 are polyester films. Others are the same as the first embodiment. According to this example, the elongation percentage of the green sheet is small,
A crimped body with good dimensional accuracy can be obtained. In this embodiment, the same effect as in the first embodiment can be obtained.

Embodiment 3 In this embodiment, as shown in FIG.
The laminate is pressed by an isostatic pressing method in a liquid. In the isostatic pressing method, the laminate 90 is sealed in a waterproof bag 12 to form a sealed body 10.
0 is immersed in a liquid 18 in a water tank 17,
Is applied. The inside of the sealing body 10 is in a vacuum state. Liquid 18 is water. The conditions for pressurizing the liquid 18 are as follows:
80 kg / cm ² , 80 ° C., 120 seconds. After pressurization, it is taken out of the waterproof bag 12 to obtain a crimped body. Others are the same as the first embodiment.

In this embodiment, since the laminated body 90 is pressed by the isotropic pressing method, the laminated body 90 is uniformly pressed from all directions. Therefore, the elongation rate and the dimensional variation of the obtained pressed body are small. In this embodiment, the same effect as in the first embodiment can be obtained.

Example 4 In this example, the elongation rate of the laminate according to Examples 1 to 3, the shrinkage rate of the press-bonded body due to firing, and the dimensional error of the ceramic substrate were measured. In the measurement, as shown in FIG. 6, the distance between the coordinates of the via holes 5 having a diameter of 0.3 mm formed in the ceramic substrate 81 was measured. Table 1 shows the results.

For comparison, ceramic multilayer substrates (Comparative Examples 1 to 4) were manufactured by the following method and measured in the same manner as above. In Comparative Example 1, in the step C, parallel flat plates were placed above and below the laminate without using a rigid container, and pressure was applied. Others are the same as the first embodiment. In Comparative Example 2, the laminate did not use unsintered green sheets, but was composed only of ceramic green sheets. Others are the same as Comparative Example 1.

In Comparative Example 3, the laminate did not use unsintered green sheets, but was composed of only ceramic green sheets. Others are the same as the first embodiment. In Comparative Example 4, the laminate did not use unsintered green sheets, but was composed only of ceramic green sheets. Others are the same as the third embodiment.

As can be seen from Table 1, in the production methods of Examples 1 to 3, the elongation of the laminate is 0.05% or less, and the shrinkage of the press-bonded body by firing is 0.32% or less. The dimensional accuracy of the ceramic substrate was ± 0.05% or less. In Comparative Examples 1 and 2 using the parallel plate, the elongation of the laminate was higher than those of the other examples. In Comparative Examples 2 to 4 in which the unsintered green sheet was not used, the shrinkage due to firing and the dimensional error of the ceramic substrate were significantly higher than those of the other examples. As can be seen from this example,
It can be seen that the production methods of Examples 1 to 3 give good results in any of the elongation rate of the laminate, the shrinkage rate of the press-bonded body due to firing, and the dimensional error of the ceramic substrate.

[0030]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a view illustrating a manufacturing process of an electronic component mounting board according to a first embodiment (C process).

FIG. 2 is a cross-sectional view of a laminated body according to the first embodiment.

FIG. 3 is a cross-sectional view of the crimped body according to the first embodiment.

FIG. 4 is a sectional view of a sintered body according to the first embodiment.

FIG. 5 is a cross-sectional view of the electronic component mounting board according to the first embodiment.

FIG. 6 is a plan view of the electronic component mounting board according to the first embodiment.

FIG. 7 is an explanatory view (C step) of a manufacturing process of the electronic component mounting board according to the second embodiment.

FIG. 8 is an explanatory view (C step) of a manufacturing process of the electronic component mounting board according to the third embodiment.

FIG. 9 is an explanatory view of a manufacturing process of a conventional electronic component mounting substrate.

[Explanation of symbols]

 1. . Rigid container, 10. . . Sealed body, 11,19. . . Parallel plate, 12. . . Waterproof bag, 18. . . Liquid, 61, 69. . . Unsintered green sheet, 71-74. . . Ceramic green sheet, 81-84. . . 8. ceramic substrate, . . Ceramic multilayer substrate, 90. . . Laminate, 91. . . Crimped body, 92. . . Sintered body,

Claims (7)

(57) [Claims] 1. A step of preparing a ceramic green sheet and an unsintered green sheet that does not sinter at the sintering temperature of the ceramic green sheet; A step B in which a green sheet is placed to obtain a laminate; a step C in which the laminate is pressed to obtain a press-bonded body while the elongation in the planar direction is kept to 0.05% or less; A ceramic multi-layer comprising: a step D for firing the pressed body at the sintering temperature of the sheet; and a step E for removing the unsintered green sheet from the pressed body to obtain a sintered ceramic substrate. Substrate manufacturing method. 2. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein the ceramic green sheet is a low-temperature fired substrate material sintered at 1000 ° C. or lower. 3. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein the unsintered green sheet is made of an alumina material. 4. The method according to claim 1, wherein the method of pressing the laminate in the step C includes applying the laminate in a rigid container having the same shape as the laminate by using a parallel flat plate from above and below. A method of manufacturing a ceramic multilayer substrate, which is a method of pressing. 5. The method according to claim 1, wherein the method of pressing the laminate in the step C includes the step of:
A method for producing a ceramic multilayer substrate, which is a method in which pressure is applied via a film having a surface roughness of 0.4 to 0.75 Ra. 6. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein the method of pressing the laminate in the step C is an isostatic pressing method in a liquid. 7. The method according to claim 1, wherein a via hole and a conductor pattern are formed in the ceramic substrate in advance.