JP3251862B2 - 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 multi-layer substrate manufactured by laminating and firing a plurality of green sheets.

[0002]

2. Description of the Related Art Conventionally, ceramic multilayer substrates are often manufactured by a green sheet laminating method. In this green sheet lamination method, after forming a via hole in a green sheet formed by a doctor blade method, the via hole is filled with a conductor paste to form a via for interlayer connection, and the same conductor paste is used. The conductor pattern is screen printed. Then, a predetermined number of the green sheets are stacked and fired to manufacture a ceramic multilayer substrate.

In some cases, in addition to the wiring pattern, an electrode pattern of a capacitor or a strip line for high-frequency use is formed as a conductor pattern on the inner layer of the ceramic multilayer substrate manufactured as described above. In this case, if the displacement of the lamination position of the green sheet of the layer forming the micro capacitor or the strip line for the high frequency application is large, the electrical characteristics are deteriorated. In recent years, a positioning mark is printed on the green sheet and the green sheet is printed. When laminating the green sheets, a positioning mark is detected by a camera, and the lamination position is corrected based on the detection mark, thereby improving the lamination position accuracy of the green sheets.

[0004]

In such a method of positioning a green sheet using a camera, the error in the stacking position of the green sheets of each layer can be reduced to about 30 μm. When forming a microcapacitor or a strip line for high-frequency use, the relative positional accuracy of the upper and lower two-layer conductor patterns sandwiching the one-layer green sheet, that is, the upper and lower two-layer green sheets on which a predetermined conductor pattern is printed The relative position accuracy becomes a problem. Therefore, if the error in the lamination position of the one-layer green sheet is 30 μm, the relative positional accuracy of the upper and lower two-layer conductor patterns is (30 ² +30 ² ) ^1/2 because the recognition operation is performed separately for the two layers. = 42 [μm]. Such a positional error does not cause a problem in a general wiring pattern, but causes a variation in characteristics of a micro capacitor or a strip line for high frequency use. In particular, in recent highly integrated and miniaturized ceramic multilayer substrates, it has become increasingly important to increase the relative positional accuracy of the upper and lower conductor patterns.

[0005] The present invention has been made in view of such circumstances, and an object of the present invention is to improve the relative positional accuracy of the upper and lower conductor patterns requiring high relative positional accuracy. An object of the present invention is to provide a method for manufacturing a ceramic multilayer substrate that can contribute to improvement in electrical characteristics.

[0006]

In order to achieve the above object, a method of manufacturing a ceramic multilayer substrate according to the present invention is characterized in that at least one of a plurality of green sheets to be laminated is formed by printing a conductive pattern after lamination. A green sheet, wherein a positioning mark is formed on the green sheet on which the unprinted green sheet is laminated, and a through hole is formed on the unprinted green sheet at a position corresponding to the positioning mark, When laminating the green sheet on the green sheet with the positioning mark,
Laminated so that the positioning mark is exposed from the through hole , thereafter, the positioning mark is detected by optical recognition means, and after correcting the position of the stacked body based on this,
A predetermined conductor pattern is printed on the unprinted green sheet (claim 1).

That is, a feature of the present invention is that green sheets (unprinted green sheets) of a layer requiring relative positional accuracy of the upper and lower conductor patterns are laminated without printing the conductor patterns, and the laminate is formed. Is corrected using an optical recognition means, and a predetermined conductor pattern is printed on the unprinted green sheet on the upper surface of the laminate. At this time, since the position correction of the laminated body is performed with reference to the positioning mark formed on the green sheet one layer below the unprinted green sheet, printing of the conductor pattern on the unprinted green sheet after lamination is also performed by one step. This is performed based on the positioning mark of the green sheet below the layer. Thereby, the relative positional accuracy between the conductor pattern printed after lamination and the conductor pattern one layer below is improved.

Further, as in claim 2, the through hole and
Position the positioning mark at the periphery of the green sheet.
It is good to form in the part which is not cut into a product when it is cut off.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a method for manufacturing a low-temperature fired ceramic multilayer substrate will be described below.

First, a method for producing a green sheet of a low-temperature fired ceramic will be described. First, CaO 10 to 55% by weight, SiO ₂ 45 to 70% by weight, Al ₂ O ₃ 0 to 30%
% Of impurities, 0-10% by weight of impurities, and B ₂ O ₃
A mixture containing 5 to 20% by weight is melted and vitrified at 1450 ° C., quenched in water, crushed and crushed to obtain CaO—SiO ₂ —Al ₂ O having an average particle size of 3.0 to 3.5 μm. _Three
Making -B ₂ O ₃ based glass powder. This glass powder 5
0 to 65% by weight (preferably 60% by weight) and 0% impurities
A low-temperature fired ceramic powder is prepared by mixing 10 to 10% by weight of alumina powder 50 to 35% by weight (preferably 40% by weight), and a solvent (eg, toluene, xylene) and a binder (eg, acrylic) are added to the low-temperature fired ceramic powder. A resin and a plasticizer (for example, DOP) are added and sufficiently kneaded to produce a slurry, and a green sheet having a thickness of, for example, 0.2 mm is produced using a normal doctor blade method.

Hereinafter, using this green sheet, FIG.
A method for manufacturing a seven-layer low-temperature fired ceramic multilayer substrate of the embodiment shown in FIG. 2 will be described. First, by cutting the elongated green sheet formed by doctor blade method into a predetermined size with cutting die or the like, for example, to form a green sheet 11 of 150mm square together, via holes (Fig at a predetermined position of the green sheets 11 (Not shown) or a positioning hole (not shown) for positioning at the time of lamination. Also, a green sheet 11b to be laminated as a fourth layer described later.
(Corresponds to unprinted green sheets in the claims)
The, as shown in FIG. 2 (a-1), for example, punched two holes 1 2 at diagonal positions. The inner diameter of each through hole 12 is, for example, 2 mm.

After that, the via hole of each green sheet 11 is filled with an Ag-based conductive paste, and the green sheets 11 and 11a of the other layers except for the fourth layer green sheet 11b having the through hole 12 have The conductor patterns 13 and 14 are screen-printed using the same Ag-based conductor paste as described above.

In the present embodiment, a conductor pattern 1 requiring high relative position accuracy in terms of high-frequency characteristics, such as an electrode pattern of a microcapacitor or a strip line for high-frequency use.
Reference numerals 4 and 15 denote third and fourth layers counted from the bottom. The third-layer conductor pattern 14 is a fine pattern having a width of, for example, 0.2 mm (see FIG. 2). Pattern 1
Similarly to 3, before the laminating step, screen printing is performed using an Ag-based conductor paste. Further, on the third layer green sheet 11a, for example, two positioning marks 16 are screen-printed using the same Ag-based conductor paste at the same time when the conductor pattern 14 is printed.

Each positioning mark 16 is a circular pattern having a diameter of 0.8 mm, for example, printed at a diagonal position corresponding to the through hole 12 having an inner diameter of 2 mm of the fourth layer green sheet 11b. As shown, the entire positioning mark 16 is accommodated and exposed in the through hole 12 when the fourth layer is stacked. The conductor pattern 15 is screen-printed on the fourth unprinted green sheet 11b having the through holes 12 after lamination.

After the conductor patterns 13, 14 and the positioning marks 16 are printed on the green sheets 11, 11a of each layer except the fourth layer as described above, the green sheets 11, 11a, 11b from the bottom to the fourth layer are printed. Are laminated, and the laminated body is heat-pressed at, for example, 80 ° C. and 15 kg / cm ² for 5 seconds to be integrated. At the time of stacking, the green sheets 11, 11a, 11b of each layer are positioned by inserting positioning pins (none are shown) into positioning holes formed in each green sheet 11.

In the state where the first to fourth layers are stacked in this manner, as shown in FIG. 1A, positioning marks are formed in two through holes 12 of the fourth unprinted green sheet 11b. The whole 16 is settled and exposed. Thereafter, the positioning marks 16 exposed in the two through holes 12 of the unprinted green sheet 11b are photographed by optical recognition means (not shown) such as two CCD cameras installed above the laminate. The image signal is processed by a controller (not shown), and the image signal is compared with a reference position pattern stored in a memory in advance to detect a positional deviation from the reference position.

Thereafter, the positioning XYθ table (not shown) on which the stacked body is placed is slid in the X direction, the Y direction, or the θ direction by a servomotor or the like to correct the positional shift of the stacked body. Align the laminate exactly to the reference position. Thereafter, a conductor pattern 15 having a width of, for example, 0.2 mm [see FIG.
(A-2) is screen printed using an Ag-based conductor paste.

In this case, the position of the laminate is corrected with reference to the positioning mark 16 formed on the green sheet 11a one layer below the unprinted green sheet 11b. The conductor pattern 15 is also printed on the basis of the positioning mark 16 of the green sheet 11a one layer below. Therefore, the recognition operation is performed once. Thereby, the relative positional accuracy between the conductor pattern 15 printed on the unprinted green sheet 11b after lamination and the conductor pattern 14 printed simultaneously with the positioning mark 16 on the green sheet 11a one layer below can be improved.

After the fourth conductive pattern 15 is printed, the fifth to seventh green sheets 11 are laminated on the laminate, and the laminate is subjected to, for example, 100 ° C. and 50 kg.
/ Cm ² for 60 seconds under heat and pressure for integration.
In the second thermocompression bonding, the temperature and pressure are set higher and the compression time is longer than in the first thermocompression bonding (first to fourth layers). This is because the first to fourth layers are press-bonded twice, and the first press is lightened to prevent the first to fourth layers from being excessively pressed.

After the second thermocompression bonding, the seven-layer laminate is cut into a predetermined size, and then fired in a normal electric continuous belt furnace at 900 ° C. for 20 minutes.

The inventors of the present invention have prepared a seven-layer low-temperature fired ceramic multilayer substrate (embodiment) manufactured as described above, and have a capacitance of a capacitor having the third and fourth conductor patterns 13 and 14 as electrodes. Was measured, and the amount of displacement between the upper and lower conductor patterns 13 and 14 (see FIG. 3) was measured by cross-sectional observation using an electron microscope. The measurement results are shown in Table 1 below.

[0022]

[Table 1]

Table 1 shows the average value of the measured capacitor capacitance and its standard deviation σ, and the upper and lower conductor patterns 13 and
14 shows the maximum value of the shift amounts of 14 (the number of measurement samples is 100). As a comparative example, the same measurement was performed on a low-temperature fired ceramic multilayer substrate in which conductor patterns of all layers including the third layer and the fourth layer were printed in advance and laminated and fired, and the measurement results are shown in Table 1. Is shown.

As is apparent from Table 1, in the embodiment, the maximum value of the deviation amount of the upper and lower conductor patterns 13 and 14 is almost の of the minimum value of the deviation amount of the comparative example, and the deviation amount is greatly increased. Can be reduced. Therefore, in the embodiment,
The deviation of the capacitor value from the design value can be significantly reduced compared to the comparative example, and the variation in the capacitor value can also be significantly reduced, so that a high-quality capacitor can be built into the ceramic multilayer substrate. For example, it is suitable for manufacturing a high-frequency component such as a coupler.

In the above embodiment, CaO—SiO ₂ —
A mixture of Al ₂ O ₃ —B ₂ O ₃ glass powder and Al ₂ O ₃ powder was used, but MgO—SiO ₂ —Al ₂ O ₃
-B ₂ O ₃ system may be a mixture of glass powder and Al ₂ O ₃ powder, also, SiO ₂ -B ₂ O ₃ based glass and Al ₂ O ₃ system, PbO-SiO ₂ -B ₂ O 10 glasses such as ₃ series glass and Al ₂ O ₃ series, cordierite series crystallized glass, etc.
A low-temperature fired ceramic material that can be fired at a temperature of 00 ° C. or less may be used. The conductor printed on the green sheet of the low-temperature fired ceramic is not limited to Ag.
A low melting point metal such as Ag / Pd, Ag / Pt, Au, or Cu may be used.

However, the present invention is not limited to low-temperature fired ceramics, but can be applied to a method of manufacturing a multilayer substrate made of other ceramics such as alumina and aluminum nitride.

In addition, according to the present invention, the position of lamination of unprinted green sheets may be changed, the number of unprinted green sheets may be plural, and the number of laminations of the multilayer substrate may be changed to a number other than seven. May be. Further, the positioning marks (through holes) may be formed at three or more places, or the through holes exposing the positioning marks may be changed to cutout portions.

[0028]

As is apparent from the above description, according to the method for manufacturing a ceramic multilayer substrate of the present invention, a green sheet (unprinted green sheet) of a layer requiring relative positional accuracy of the upper and lower conductor patterns is required. About, after lamination,
After correcting the position of the laminate with reference to the positioning mark of the green sheet one layer below, the conductor pattern is printed on the unprinted green sheet on the upper surface of the laminate. The relative position accuracy between the conductor pattern and the conductor pattern one layer below can be improved, and the electrical characteristics can be improved (claim 1).

Further, the through hole and the positioning mark are
If the product is finally cut off around the lean sheet
Formed on the surface of the product.
No marks remain (claim 2).

[Brief description of the drawings]

FIG. 1 is a process chart for explaining a method of manufacturing a ceramic multilayer substrate according to an embodiment of the present invention.

FIG. 2A is a plan view of a fourth-layer green sheet, FIG. 2A is an enlarged view of a fourth-layer conductive pattern, FIG.
-1) is a plan view of a third-layer green sheet, (b-2)
Is an enlarged view of the third layer conductor pattern

FIG. 3 is a partially enlarged longitudinal sectional view for explaining a positional shift between upper and lower conductor patterns.

[Explanation of symbols]

11, 11a: green sheet, 11b: unprinted green sheet, 12: through hole, 13 to 15: conductor pattern,
16 Positioning mark.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshihiro Nakai 2701-1, Iwakura, Omine-cho, Omine-cho, Mine-shi, Yamaguchi Pref. 58) Fields surveyed (Int.Cl. ⁷ , DB name) H05K 3/46

Claims (2)

(57) [Claims] 1. A method of manufacturing a ceramic multilayer substrate by laminating and firing a plurality of green sheets, wherein at least one of the plurality of green sheets is an unprinted green sheet on which a conductor pattern is printed after lamination. A positioning mark is formed on the green sheet for laminating the unprinted green sheet, and a position corresponding to the positioning mark is formed on the unprinted green sheet.
Forming a through hole , when laminating the unprinted green sheet on the green sheet having the positioning mark, laminating the positioning mark so that the positioning mark is exposed from the through hole ; After detecting by the recognition means and correcting the position of the laminate based on this,
A method for manufacturing a ceramic multilayer substrate, comprising printing a predetermined conductor pattern on the unprinted green sheet. 2. The method according to claim 2, wherein the through hole and the positioning mark are
It is finally cut off around the green sheet to become a product.
2. The method according to claim 1, wherein the first and second portions are formed in a portion that does not meet the requirements.
Method for manufacturing a ceramic multilayer substrate.