JP4110536B2 - Multilayer ceramic aggregate substrate and method for producing multilayer ceramic aggregate substrate - Google Patents

Description

  The present invention relates to a multilayer ceramic substrate using a non-shrinkage process, and particularly to a large multilayer ceramic aggregate substrate and a multilayer ceramic substrate obtained by dividing the aggregate substrate into a plurality of small pieces.

  Today, LSIs and chip parts are increasingly reduced in size and weight, and the wiring board on which these are mounted is also desired to be reduced in size and weight. In response to such a demand, the multilayer ceramic substrate having internal electrodes and the like arranged in the substrate enables the required high-density wiring and can be thinned. In the field of mobile communication terminal equipment and the like, it is widely used to configure various electronic components such as antenna switch modules, PA module substrates, filters, chip antennas, and various package components.

  In order to mount electronic parts, semiconductor integrated circuits, etc. at a high density, the multilayer ceramic substrate has via holes formed in a ceramic green sheet made of low-temperature fired ceramic material: LTCC (Low Temperature Co-fired Ceramics), and a conductor is formed in the hole. After filling, an electrode pattern constituting a circuit is printed on the surface of the sheet, and a plurality of these sheets are laminated and pressed to form an unfired multilayer ceramic substrate. Then, it is manufactured by firing at a temperature of 1,000 ° C. or lower. At this time, the volume of the unsintered multilayer ceramic substrate is reduced and densified. This shrinkage is inevitable because the ratio between the density of the green sheet laminate and the theoretical density of the ceramic body, that is, the relative density is usually 45 to 65%, but the relative density becomes about 95% or more by firing. . Usually, an unsintered multilayer ceramic substrate is placed on a ceramic base plate and fired in an electric furnace. The shrinkage rate due to firing is generally in the range of 10 to 25% in terms of linear shrinkage rate. Since shrinkage due to firing differs from lot to lot, misalignment occurs in a circuit that requires high-density wiring, which is a problem in a multilayer ceramic substrate that requires a precise circuit.

Therefore, Patent Document 1 (Japanese Patent No. 2617643) describes a non-shrinkage process which is a method for reducing shrinkage during firing of an unsintered multilayer ceramic body.
Here, the non-shrinking process is to prepare a constrained green sheet made of an inorganic composition paste in which an inorganic material (such as alumina) that is not sintered at the firing temperature of the substrate green sheet is dispersed in an organic binder. It is provided in close contact with the upper and lower surfaces of an unsintered multilayer ceramic substrate and fired thereon. At this time, contraction of the substrate surface is suppressed by the contraction suppressing action of the constraining layer.

  By the way, as one method for cost reduction and small substrate manufacturing when manufacturing such a multilayer ceramic substrate, a large ceramic aggregate substrate is obtained and divided into a plurality of so-called multi-chips. There is a way to be called. In this method, a non-sintered multilayer ceramic body on which green sheets for a substrate are laminated is formed on both sides or one side by intersecting longitudinal and lateral dividing grooves and sintered to produce a multilayer ceramic aggregate substrate. . Thereafter, the multilayer ceramic substrate is obtained by breaking along the dividing grooves or by cutting with a grindstone cutter or the like. Such a multi-cavity method using divided grooves is also used in a non-shrink process, and is disclosed in, for example, Patent Document 2 and Patent Document 3.

  In Patent Document 2, in order to suppress the warpage of the substrate, the unsintered multilayer ceramic body and the constrained green sheet are pressure-bonded to obtain sufficient adhesion strength, and then cut in the thickness direction of the multilayer ceramic body from above the constraining layer. A dividing groove is formed. Further, at this time, warping and deformation can be suppressed by setting the distance between the end of the dividing groove and the edge of the multilayer ceramic body to 3 mm or more.

  In Patent Document 3, a wiring circuit layer is formed in a region 3 mm or more inside from an edge of a ceramic green sheet for a substrate in order to prevent chipping or cracking of the end surface of the substrate. A dividing groove is formed by cutting 0.01 to 1 mm so as not to cross the layer. As a result, the central portion of the end face is prevented from being dented and chipping and cracking can be prevented.

Japanese Patent No. 2617643 JP 2002-185136 A JP 2003-249755 A

In order to take a large number of pieces, it is necessary to form dividing grooves on the surface of the sintered multilayer ceramic aggregate substrate for easy division. As described above, as the means for forming the dividing grooves, the grooves are usually formed vertically and horizontally on the surface of the multilayer ceramic body in an unsintered state, that is, in a green state, using a device such as a knife cutter. However, in the non-shrinkage process, the presence of such divided grooves causes variations in shrinkage behavior between the periphery and the center of the groove. This also applies to the thickness direction of the substrate (the depth direction of the dividing grooves), and a gradient occurs in the amount of contraction between the surface side and the center of the cross section.
Further, the conventional dividing groove is, for example, substantially V-shaped, which simply reflects the cutting edge of the cutter. From the standpoint of ease of division, the cut groove should be deep, but conversely, the deeper the groove, the worse the handling. In other words, the upper part is sunk and the sheet is deformed, and the cutting edge of the blade is deteriorated and the sheet is deformed. As a result, there was a problem that cracking occurred during the sintering process. Such a problem becomes prominent particularly in the case of a thick ceramic substrate, and appears as an end defect in a small multilayer ceramic substrate.

Therefore, the present invention is a multi-layer ceramic aggregate substrate formed by a non-shrink process in which divided grooves are formed, and the divided grooves are formed by relatively shallow cut grooves, the shape of the divided grooves is changed, and the handleability is good but the dividing property is improved. An object of the present invention is to provide a multilayer ceramic aggregate substrate that is excellent and free from defects such as sheet deformation and a method for producing the multilayer ceramic aggregate substrate .

The present invention provides a substrate-forming green by forming divided grooves having a substantially V-shaped cross section in the longitudinal and transverse directions of both sides or one side of an unsintered multilayer ceramic body in which substrate green sheets made of a low-temperature sintered material containing ceramic are laminated. A constraining layer composed mainly of inorganic particles that are not sintered at the firing temperature of the sheet is provided on both sides or one side of the unsintered multilayer ceramic body, and the unsintered multilayer ceramic body provided with the constraining layer is provided in the unsintered multilayer ceramic body. A multilayer ceramic aggregate substrate obtained by sintering at a temperature at which the ceramic body is sintered and removing the constraining layer from the fired multilayer ceramic body , wherein at least one dividing groove of the multilayer ceramic aggregate substrate is formed from a surface portion. The multilayer ceramic aggregate substrate is characterized in that the inside is a slightly swollen cross section having a substantially Ω shape. In the present invention, the substantially U shape refers to an Ω shape, a U shape, or the like in which the lower part of the dividing groove is widened. In a broad sense, it is not a narrow shape like a V shape.

In the multilayer ceramic aggregate substrate of the present invention, it is desirable that the depth of the dividing groove having a substantially Ω-shaped cross section is 2/3 or less of the thickness of the multilayer ceramic aggregate substrate in both sides.

The present invention provides a step of preparing a substrate green sheet made of a low-temperature sintered material containing ceramic, a step of forming a desired conductor pattern with a conductor paste on a desired green sheet of the substrate green sheet, A step of laminating and pressing a green sheet for a substrate having a conductor pattern appropriately formed to produce an unsintered multilayer ceramic body, and a cross section having a depth of 10 to 200 μm in both longitudinal and lateral directions of the unsintered multilayer ceramic body Forming a substantially V-shaped dividing groove so that the depth (m2) of the dividing groove is equal to or less than 30% of the thickness of the unsintered multilayer ceramic body; A step of providing a constraining layer mainly composed of inorganic particles that are not sintered at the firing temperature on both sides or one side of the unsintered multilayer ceramic body, and an unsintered multilayer ceramic provided with the constraining layer. A step of sintering the body at a temperature at which sintering of the non-sintered multilayer ceramic structure, after firing, comprising a step of removing the constraining layer from the multilayer ceramic body, at least one of the said sintering process the substantially V-shaped section of the dividing groove, the surface portion than the inside of it is slightly swelled cross section Ω-shaped groove and without, multilayer ceramic structure of the depth of the dividing groove (m1) is sintered to fit both sides It is formed so that it may become 2/3 or less of this thickness, The manufacturing method of the multilayer ceramic aggregate substrate characterized by the above-mentioned.

In the method for producing a multilayer ceramic aggregate substrate of the present invention, the depth of the divided grooves after sintering is greater than the depth ratio of the depth (m2) of the divided grooves before sintering to the thickness of the unsintered multilayer ceramic body. The depth ratio of the (m1) to the thickness of the sintered multilayer ceramic body is increased.

In the method for producing a multilayer ceramic aggregate substrate of the present invention, the thickness of the unsintered multilayer ceramic body before sintering is 0.34 to 1.99 mm, and the thickness of the sintered multilayer ceramic body after sintering is 0.18. It is desirable to be -1.07 mm.

ADVANTAGE OF THE INVENTION According to this invention, the handling property of the multilayer ceramic body in which the division | segmentation groove | channel was formed is favorable, and the manufacturing method of the multilayer ceramic aggregate substrate which became the division | segmentation groove | channel which is easy to divide | segment after sintering is provided. be able to.

Hereinafter, the multilayer ceramic aggregate substrate and multilayer ceramic substrate of the present invention will be described including the manufacturing method.
FIG. 1 is a cross-sectional view showing an example of a manufacturing process of a multilayer ceramic aggregate substrate. The process sequence and materials are only examples, and are not necessarily limited as described below, and a plurality of processes may be performed simultaneously. In some cases, unnecessary steps may not be performed. FIG. 2 is an example of a perspective view of a multilayer ceramic aggregate substrate. However, the number of small pieces of the multilayer ceramic substrate is arbitrary. FIG. 3 is a cross-sectional view showing a dividing groove portion of the multilayer ceramic aggregate substrate. FIG. 4 is a cross-sectional view showing a divided groove portion of the multilayer ceramic substrate after being divided along the divided grooves.

An embodiment of a multilayer ceramic aggregate substrate will be described with reference to FIG. First, a slurry made of a mixture of ceramic material powder, glass component powder, organic binder, plasticizer, and solvent, which can be fired at low temperature, is deposited on an organic carrier film (PET film) to an appropriate thickness by a doctor blade method, approximately 20 to A plurality of substrate green sheets 1a, 1b, and 1c are prepared to have a thickness of 200 μm. The production of the green sheet made of ceramic that can be fired at a low temperature is not limited to the doctor blade method, and can be produced by, for example, a rolling method or a printing method.
The ceramic material that can be sintered at a low temperature is a ceramic material that can be fired simultaneously with a conductive paste such as silver at 800 to 1000 ° C., and any so-called LTCC ceramic can be used. As an example, when Al, Si, Sr, and Ti, which are main components, are converted into Al ₂ O ₃ , SiO ₂ , SrO, and TiO ₂ , respectively, Al ₂ O ₃ : 10 to 60% by mass, SiO ₂ : 25 to 25% 60% by mass, SrO: 7.5 to 50% by mass, TiO ₂ : 20% by mass or less (including 0), Bi, Na, K, Co as subcomponents with respect to 100 parts by mass of the main component At least one of these groups is 0.1 to 10% by mass in terms of Bi ₂ O ₃ , 0.1 to 5% by mass in terms of Na ₂ O, 0.1 to 5% by mass in terms of K ₂ O, CoO contain 0.1 to 5 wt% in terms of further, Cu, Mn, 0.01 to 5 mass% of at least one kind selected from the group of Ag in terms of CuO, 0.01 to 5 mass% with MnO ₂ in terms of , Containing 0.01 to 5% by mass of Ag and other inevitable impurities The compound once calcined at 700 ° C. to 850 ° C., can be mentioned which was triturated consisting milled particles having an average particle diameter of 0.6~2μm dielectric ceramic composition.

  Via holes are appropriately formed in the substrate green sheets 1a, 1b, and 1c, and via conductors 3 are formed in the via holes with a conductor paste such as Ag. Further, the conductor pattern 2 is formed on the surface of the desired substrate green sheet with the same conductor paste to a thickness of 5 to 35 μm by printing. An inductor, a transmission line, a capacitor, a ground electrode, and the like are formed by these conductor patterns, and are connected by the via conductor to appropriately constitute a circuit. The desired substrate green sheet refers to a green sheet on which the via conductor 3 and the conductor pattern 2 are formed as required for circuit design of the multilayer ceramic substrate. In this example, via conductors and conductor patterns were formed on all the substrate green sheets.

Next, a plurality of green sheets 1a, 1b, and 1c for substrates on which via conductors 3 and / or conductor patterns 2 are formed are laminated by repeating press bonding and carrier film peeling steps to produce an unsintered multilayer ceramic body 7. To do.
First, the substrate green sheet 1a which is the surface layer of the unsintered multilayer ceramic body 7 is set on a fixing film, and is pressed and pressure-bonded at a predetermined pressure, temperature and time with an upper mold. For example, the pressure is 10 to 50 kg / cm ² , the temperature is 30 to 60 ° C., and the time is 3 to 15 seconds. The upper and lower molds for thermocompression bonding may have a simple flat plate shape with a built-in heater. When the press bonding is completed, the carrier film of the substrate green sheet 1a is peeled off. At this time, the green sheet is firmly fixed to the fixing film and is not peeled off together with the carrier film.
Next, a second-layer substrate green sheet 1b is laminated. On the green sheet for substrate 1b, a conductor pattern 2 constituting a predetermined internal circuit is printed on the inner layer. The main surface of the substrate green sheet 1b is set so as to be in contact with the first-layer substrate green sheet 1a, and is pressed and pressed in the same manner as in the case of the first-layer substrate green sheet 1a. At this time, if the pressing temperature is set to a temperature at which the adhesive in the printing paste is softened and fixed, the printing unit is bonded to the other substrate green sheet by the applied pressure. Therefore, the green sheets for substrates are bonded together via the printed conductor paste. In addition, where there is no electrode and the ceramic layers are in direct contact with each other, they are softened, fixed and bonded in the same way as when the electrodes are interposed. Although the pressure bonding temperature at this time depends on the type of the pressure-sensitive adhesive, it may be a low temperature of about 40 to 90 ° C., and the bonding strength can be adjusted by changing the pressure. After the pressure bonding, the carrier film of the substrate green sheet 1b is peeled off. After the third layer green sheet for substrate 1c, a series of operations similar to those described for the lamination of the second layer substrate green sheet 1b are repeated. Moreover, in order to integrate a laminated body strongly, you may perform a crimping | compression-bonding process further. Although the number of layers is three here, the number of laminated layers cannot be specified, and may vary depending on the circuit configuration and may be a non-sintered multilayer ceramic body of 10 layers or more.

  External electrodes 4 and external terminal electrodes 6 are printed on the upper and lower surfaces (substrate surfaces) of the unsintered multilayer ceramic body by using a conductive paste mainly composed of Ag as appropriate. Further, an overcoat material 5 is appropriately formed around the conductor patterns 4 and 6 on the substrate surface. As the material of this overcoat material, it is desirable that the sintering shrinkage characteristic and the thermal expansion characteristic are similar to the raw material of the unsintered multilayer ceramic body. For example, what added the addition component for providing the function which improves the visibility of a coat part to the slurry of the same material as a board | substrate sheet | seat is mentioned. By covering the periphery of the surface conductor pattern with an overcoat to form an electrode coating region, mechanical protection of the surface conductor pattern and solder provided on the conductor pattern in a later process flow out and contact the conductive portion Can prevent short circuit. The conductor pattern and the overcoat material on the surface of the substrate do not necessarily need to be provided in the state of an unsintered multilayer ceramic body, and may be formed on the sintered multilayer ceramic body.

Next, as shown in FIG. 5, cut grooves that intersect in the vertical and horizontal directions are formed on the surface of the unsintered multilayer ceramic body 7, usually both the upper and lower surfaces, by a jig such as a knife cutter, A dividing groove 14 is formed. Although the number of divisions of this dividing groove varies depending on the size of the collective substrate and the size of the product substrate, a position where adjacent substrates do not interfere with each other so as not to adversely affect the conductor pattern constituting the circuit, a distance of about 2 to 15 mm. Place it and make a notch. This dividing groove is usually V-shaped, and the depth of the groove is as shallow as about 0.01 to 0.2 mm. The depth varies depending on the thickness of the unsintered multilayer ceramic body, but the sum of the groove depths on the upper and lower surfaces is set to be 30% or less of the thickness of the unsintered multilayer ceramic body 7. If this depth is deep, the cutter will be unsatisfactory and will be deformed, and will be the starting point of cracks during the sintering process, which is not desirable. Further, the dividing groove may be either the upper surface or the lower surface instead of the both surfaces.
Then, it thermocompression-bonds at 100-400 kg / cm < ² >, 85 degreeC with a CIP apparatus, and it is set as the unsintered multilayer ceramic body 7 with which each layer was integrated (FIG. 1 (a)).

On the other hand, a ceramic slurry is prepared by adding an organic binder, a plasticizer, and a solvent to an inorganic material that is not sintered at the firing temperature of the unsintered multilayer ceramic body 7, and this is formed on a carrier film by a doctor blade method with a predetermined thickness (for example, 100 to 200 [mu] m) to produce a constrained green sheet. The ceramic material used for the constrained green sheet does not sinter at the firing temperature (about 800 to 1000 ° C.) of the glass ceramic material used for the substrate green sheet, and has the function of not shrinking the surface of the unsintered multilayer ceramic body. Anything is acceptable. As the inorganic material, various types of alumina are available at low cost, and therefore alumina is generally used. In addition, the same organic binder, plasticizer, and solvent as those used for the green sheet for the substrate can be used.
Then, the constrained green sheets prepared above are aligned on the upper and lower surfaces of the unsintered multilayer ceramic body 7 and laminated so that the thickness of the constraining green sheets is about 200 μm. Then, a laminated body in which the constraining layer and the unsintered multilayer ceramic body are integrated is obtained by thermocompression bonding at 100 to 400 kg / cm ² and 85 ° C. (FIG. 1B).

Next, the laminated body in which the constraining layer is integrated is heat-treated in a firing furnace, and the unfired multilayer ceramic body is sintered at a temperature of 800 to 1000 ° C. while appropriately degassing the binder of the constraining layer. I do.
After firing, the constraining layer of the sintered multilayer ceramic body is removed by ultrasonic cleaning, blasting, or the like to obtain the multilayer ceramic aggregate substrate 11 (FIG. 1 (c)).
An example of the multilayer ceramic aggregate substrate 11 is shown in FIG. As described above, the large collective substrate 11 is formed with the dividing grooves 14 in the vertical direction and the horizontal direction, and can be broken along the dividing grooves to obtain a small multilayer ceramic substrate. Or it can cut | disconnect with a grindstone cutter and a multilayer ceramic substrate can be obtained.

  FIG. 3 shows a cross-sectional view of the dividing groove portion of the multilayer ceramic aggregate substrate thus obtained. FIG. 3A is an example of an embodiment of the present invention, and dividing grooves 14 are formed on the upper and lower surfaces of the multilayer ceramic aggregate substrate 11. The dividing groove 14 has a substantially U-shaped cross section. When the dividing groove 14 is viewed in more detail, the structure inside the dividing groove 14 has a shape in which the inside is slightly swollen from the surface portion of the substrate. Moreover, FIG.3 (b) has shown another form of the Example of this invention. The dividing groove 14 of this embodiment has a substantially U-shaped cross section. When the dividing groove 14 is seen in more detail, it has a substantially linear portion from the substrate surface to the bottom of the dividing groove 14.

An example of the dividing groove formed in the unsintered multilayer ceramic body of the dividing groove of the present invention is shown in FIG. 5, but the dividing groove 14 formed in the unsintered multilayer ceramic body 7 has a substantially V-shaped cross-sectional shape. is doing. After dividing the unsintered multilayer ceramic body, the dividing groove 14 becomes a substantially U-shaped dividing groove 14 as shown in FIG.
In the present invention, it can be seen that the ratio of the depth of the divided groove 14 to the substrate thickness is increased by this sintering. In the state of the unsintered multilayer ceramic body 7, the depth (m2) of the divided groove 14 is The dividing grooves on the upper and lower surfaces are combined and set to 30% or less of the thickness (l2) of the unsintered multilayer ceramic body 7. That is, in the present invention, (m2 × 2) / l2 is configured to be 30% or less. Moreover, it is preferable that the division | segmentation groove | channel formed in this unsintered multilayer ceramic body shall be 0.2 mm or less in depth . If the depth is too deep, problems such as deformation of the ceramic body occur even if the green multilayer ceramic body is thick. After the sintering, the depth (m1) of the dividing groove 14 is configured to be 2/3 or less of the thickness (l1) of the multilayer ceramic aggregate substrate 11 by combining the dividing grooves on the upper and lower surfaces.
By constructing the dividing grooves in this way, a shallow V-groove is formed when unsintered, so that the workability and handling properties of the cut groove formation are improved, and after sintering, the depth is deeper than the substrate thickness compared with the unsintered state. A U-shaped groove can be formed, whereby the distance between the upper and lower divided grooves is shortened, and the U-shaped groove spreads to facilitate division and good handling.

FIG. 4 shows a cross-sectional view of the divided groove portion of the multilayer ceramic substrate obtained by dividing the multilayer ceramic aggregate substrate 11 of the present invention along the divided grooves. FIG. 4A shows an embodiment in which the multilayer ceramic aggregate substrate 11 of FIG. 3A is divided. In this embodiment, the upper end portion 15a and the lower end portion 15b of the side surface of the multilayer ceramic substrate 15 have a notch portion 16 of a split groove trace, and the notch portion 16 of the split groove trace has an upper end portion 15a and a lower end portion. It has a portion 16a that is more concave than 15b. The concave portion 16a is a vertical line 18 drawn in the thickness direction from the end portion (upper end portion 15a or lower end portion 15b) of the surface (upper surface or lower surface) of the substrate in the cutout portion 16 of the split groove trace. In this case, the portion is recessed from the perpendicular 18 in the internal direction of the substrate (center direction of the substrate plane).
FIG. 4B shows an embodiment in which the multilayer ceramic aggregate substrate 11 of FIG. 3B is divided. In this embodiment, the upper end portion 15a and the lower end portion 15b of the side surface of the multilayer ceramic substrate 15 have a notch portion 16 of the split groove trace, and the notch portion 16 of the split groove trace is the upper end portion 15a or the lower end portion. A portion 16b that is substantially perpendicular to the substrate plane from the portion 15b is provided.

  The divided side surface shape of this embodiment has a notch portion 16 of the division groove trace, and is formed in a step shape in which the central portion of the side surface is convex. By adopting such a convex shape, it is possible to prevent chipping or cracking at the corners of the side surface of the multilayer ceramic substrate. Such a side surface is formed by dividing a large number of pieces. When only one side surface of the substrate is formed by dividing, two side surfaces of the substrate are formed by dividing the one side surface. In the case where the three side surfaces or the four side surfaces of the substrate are formed by division on the two side surfaces, the notches are formed on the three side surfaces or the four side surfaces.

Al ₂ O ₃ : 48% by mass, SiO ₂ : 38% by mass, SrO: 10% by mass, TiO ₂ : 4% by mass, Bi ₂ O ₃ : 2.5% by mass with respect to 100 parts by mass of the main component, A ceramic material having a composition of Na ₂ O: 2% by mass, K ₂ O: 0.5% by mass, CuO: 0.3% by mass, MnO ₂ : 0.5% by mass was calcined at 800 ° C. for 2 hours, 15 parts by mass of PVB as an organic binder and 10 parts by mass of DOP (bis (2-ethylhexyl phthalate)) as a plasticizer are added to 100 parts by mass of finely pulverized ceramic powder having an average particle size of about 1 μm. A mixture of ethanol and butanol was used as a solvent, and the mixture was dispersed in a ball mill for 20 hours. The obtained slurry was defoamed under reduced pressure to partially volatilize the solvent, and formed into a sheet by the doctor blade method. The obtained green sheet for a substrate was cut into a predetermined size together with a carrier film, and a predetermined conductor pattern was formed by screen printing with an Ag paste. Each layer of the green sheet for the substrate was sequentially aligned, and then thermocompression bonded at about 50 ° C. and a pressure of 40 kg / cm ² (3.9 MPa) to obtain a laminate in a temporarily pressed state. Then, the division | segmentation groove | channel shown in Table 1 was formed in the surface of the laminated body with the knife cutter. Then, a surface layer conductor pattern and an overcoat material were formed, and thermocompression bonded at 100 Kg / cm ² (9.8 MPa) and 85 ° C. with a CIP device to obtain an unsintered multilayer ceramic body in which the layers were integrated. The thickness of the unsintered multilayer ceramic body is shown in Table 1.

Next, as a constrained green sheet, 5 parts by mass of PVB as an organic binder and 3 parts by mass of DOP as a plasticizer are added to 100 parts by mass of alumina powder having an average particle size of 1.5 μm, and ethanol and butanol as solvents. And the mixture was dispersed in a ball mill for 10 hours. The obtained slurry was defoamed under reduced pressure to partially volatilize the solvent, and formed into a sheet by the doctor blade method. The obtained constraining green sheet was peeled from the carrier film and cut into the same size as the unsintered multilayer ceramic body. This constraining green sheet was thermocompression bonded to both sides of the unsintered multilayer ceramic body with a CIP device at 120 kg / cm ² (11.8 Mpa) at 85 ° C., and the constraining layer and the unsintered multilayer ceramic body were integrated. . The thickness of the constraining layer is shown in Table 1.
The laminate was debindered and held at 900 ° C. for 2 hours to obtain a sintered body. The constrained layer of the sintered body was removed, ultrasonic cleaning was performed, and residual alumina was removed to obtain a multilayer ceramic aggregate substrate.
Then, the multilayer ceramic substrate of the small piece was obtained by fracture | rupturing along the notch | incision of a division groove | channel, or cut | disconnecting with a grindstone. There were 90 multilayer ceramic substrates.

The evaluation item is to evaluate the workability at the time of forming the cut groove for the split groove formed in the unsintered multilayer ceramic body with good (○) or bad (×), and the split groove of the multilayer ceramic aggregate substrate after sintering. Evaluate the form and ease of breakage for 90 pieces with good (○) or bad (×), and evaluate the defect status such as cracks or chips on the side with (○) or with (×), The handling properties after sintering are those that were already cracked after firing, or those that were cracked during cleaning after firing (when set to a jig or ultrasonic cleaning). Evaluated as no (○).
The results are shown in Table 1.

According to the results in Table 1, in sample No. 6, the depth of the cut groove for the dividing groove is 28 % of the thickness of the unsintered multilayer ceramic body on both sides, and the workability of the cut groove is good. However, the depth of the divided groove after sintering is 80% of the thickness of the multilayer ceramic aggregate substrate on both sides, which is larger than 2/3, the handling property after sintering is poor, and many cracks occur. It was not preferable.
In Sample Nos. 7 and 8, the depth of the cut groove for the divided groove and the depth of the divided groove after sintering were good, but the shape of the divided groove after sintering was V-shaped, Evaluation of easiness of division was not preferable.

  In sample No. 9, the depth of the cut groove for the split groove is 33% of the thickness of the unsintered multilayer ceramic body on both sides, and is too deep, so the workability during the cut groove forming operation is not preferable. It was. As this poor workability, when lifting the blade pushed into the ceramic body, not only the blade but also the ceramic body may be lifted together, and in such a state, it leads to deformation of the ceramic body, It is not preferable. The depth of the cut groove is also related to the thickness of the ceramic body. As shown in Sample No. 17, the depth of the cut groove for the divided groove is equal to the thickness of the unsintered multilayer ceramic body. Even if it is 35%, the workability during the cut groove forming work may be good. This is because the depth of the cut groove for the split groove is 0.06 mm, which is deeper than the thickness of the unsintered multilayer ceramic body, but is not too deep as a real number (0.2 mm or less). The workability during the groove forming work was good. That is, even if it exceeds 30%, the evaluation of this point may be good. However, in Sample No. 17, the depth of the divided groove after sintering is 78% of the thickness of the multilayer ceramic aggregate substrate on both sides, which is larger than 2/3, the handling property after sintering is poor, and cracks are present. As a result, it was not preferable.

In Sample Nos. 10 and 11, the depth of the cut groove for the split groove was 43% and 65% of the thickness of the unsintered multilayer ceramic body in both sides, which was too deep. Workability was not preferable.
In Sample No. 22, the depth of the cut groove for the split groove was 25% of the thickness of the unsintered multilayer ceramic body on both sides, but the actual cut depth was 0.25 mm in one cut groove. In addition, the depth itself is large, and workability at the time of forming the cut groove is not preferable. Further, the depth of the divided groove after sintering is 75% of the thickness of the multilayer ceramic aggregate substrate on both sides, which is larger than 2/3, the handling property after sintering is poor, and many cracks are generated. There wasn't.

From this result, the depth of the cut groove for the split groove is 30% or less of the thickness of the unsintered multilayer ceramic body on both sides, and the depth of the split groove on the multilayer ceramic aggregate substrate is multilayer on both sides. When the thickness of the ceramic aggregate substrate is 2/3 or less and the sectional shape of the dividing groove is substantially U-shaped, the workability of the cutting groove for the dividing groove is good and the handling property after sintering is good. It is easy to divide and there is no chipping / cracking, and a multilayer ceramic substrate can be obtained. At this time, the depth of the cut groove for the dividing groove is preferably 0.2 mm or less.
From the above, it was found that a good multilayer ceramic substrate can be obtained according to the present invention.

It is a figure which shows one Example of the multilayer ceramic aggregate substrate of this invention, and demonstrates with the manufacture process. It is a perspective view which shows an example of the multilayer ceramic aggregate substrate of this invention. It is sectional drawing of the division groove part of the multilayer ceramic aggregate substrate of this invention. It is sectional drawing of the division groove part of the multilayer ceramic substrate of this invention. It is sectional drawing of the notch groove part for the division grooves of the non-sintered multilayer ceramic body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1c: Ceramic green sheet 2: Internal electrode 3: Via hole 4: External electrode 5: Overcoat layer 6: External terminal electrode 7: Unsintered multilayer ceramic body 8: Sheet-like upper surface constrained layer 9: Sheet-like lower surface constrained layer 10: Unsintered multilayer ceramic body (laminated body) provided with a constraining layer
11: Multilayer ceramic aggregate substrate 14: Divided groove 15: Multilayer ceramic substrate 16: Notch portion of the divided groove trace

Claims (5)

A non-sintered multilayer ceramic body formed by laminating a green sheet for a substrate made of a low-temperature sintered material containing ceramic is formed with split grooves having a substantially V-shaped cross section in the longitudinal and lateral directions on one side , and the firing temperature of the green sheet for a substrate Then, a constraining layer mainly composed of inorganic particles that are not sintered is provided on both sides or one side of the unsintered multilayer ceramic body, and the unsintered multilayer ceramic body provided with the constraining layer is sintered on the unsintered multilayer ceramic body. A multilayer ceramic aggregate substrate obtained by sintering at a sintering temperature and removing the constraining layer from the fired multilayer ceramic body , wherein at least one dividing groove of the multilayer ceramic aggregate substrate is more inside than the surface portion. A multi-layer ceramic aggregate substrate characterized by having a slightly swollen cross section and a substantially Ω shape. 2. The multilayer ceramic aggregate substrate according to claim 1, wherein a depth of the divisional groove having a substantially Ω-shaped cross section is 2/3 or less of a thickness of the multilayer ceramic aggregate substrate in total on both surfaces. Preparing a green sheet for a substrate made of a low-temperature sintered material containing ceramic;
Of the green sheets for the substrate, forming a desired conductor pattern with a conductor paste on a desired green sheet;
Laminating a green sheet for a substrate having the conductor pattern appropriately formed, and pressing to produce a green multilayer ceramic body,
The green and sintered multilayer ceramic structure of both surfaces or one surface depth substantially V-shaped section of the dividing groove of 10~200μm in vertical and horizontal direction, the depth of the dividing groove (m2) and the combined two-sided non-sintered multilayer ceramic structure Forming to be 30% or less of the thickness of
Providing a constraining layer mainly composed of inorganic particles that are not sintered at the firing temperature of the substrate green sheet on both sides or one side of the unsintered multilayer ceramic body;
Sintering the unsintered multilayer ceramic body provided with the constraining layer at a temperature at which the unsintered multilayer ceramic body is sintered;
After firing, removing the constraining layer from the multilayer ceramic body,
At least one of said substantially V-shaped section of the dividing groove in the sintering process, the inside of it is slightly swelled cross section Ω-shaped groove and without the surface portion, the depth of the dividing groove (m1) is double-sided alignment A method for producing a multilayer ceramic aggregate substrate, characterized in that the multilayer ceramic body is formed to be 2/3 or less of the thickness of the multilayer ceramic body after sintering. The depth of the divided groove depth (m1) after sintering is greater than the depth ratio of the depth of the divided groove (m2) before sintering to the thickness of the sintered multilayer ceramic body. 4. The method of manufacturing a multilayer ceramic aggregate substrate according to claim 3, wherein the depth ratio is increased. The thickness of the unsintered multilayer ceramic body before sintering is 0.34 to 1.99 mm, and the thickness of the sintered multilayer ceramic body after sintering is 0.18 to 1.07 mm. Item 5. The method for producing a multilayer ceramic aggregate substrate according to Item 3 or 4.

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