JP2006351833A - Method of manufacturing multilayer ceramic substrate, and multilayer ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method related to a multilayer ceramic substrate reducing the transformation region of the end of the substrate, being capable of increasing the number of products manufactured per one substrate and baked at a low temperature. <P>SOLUTION: The method for manufacturing the multilayer ceramic substrate has a step in which a green sheet composed of ceramics baked at the low temperature is prepared; and the step in which the upper section of a carrier film is coated with ceramic slurry mainly using an inorganic material not baked at the baking temperature of the green sheet, the carrier film is dried, and a constraint sheet is prepared. The method further has the step in which conductor patterns and via conductors are manufactured of conductor paste in a desired green sheet, and the step in which a green-sheet laminate is manufactured by laminating the green sheets with the formed via conductors and/or conductor patterns. The method further has the step in which the green-sheet laminate is baked as the constraint sheets are laminated on both surfaces or one surface of the green-sheet laminate, and the step in which the constraint sheets are removed from the laminate after a baking. In the manufacturing method for the multilayer ceramic substrate, a contact-bonding pressure when the constraint sheets and the green-sheet laminate are compression bonded is set at the compression bonding pressure or higher when the green-sheet laminate is manufactured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a low-temperature co-fired (LTCC) multilayer ceramic substrate having high accuracy and high flatness used for a high-density multilayer wiring substrate and a method for manufacturing the same.

  In recent years, LSIs and chip parts have been reduced in size and weight, and a wiring board on which these are mounted is also desired to be reduced in size and weight. In response to such demands, multilayer ceramic substrates with internal electrodes and the like in the substrate are required in today's electronics industry because they enable the required high-density wiring and can be made thinner. .

  A multilayer ceramic substrate is made by adding organic binder, plasticizer, solvent, etc. to ceramic particles to form a slurry. After forming a green sheet by the doctor blade method, a conductive paste containing powder of low resistance metal such as silver is printed by the printing method. A wiring conductor pattern is formed on a glass ceramic green sheet, and then a plurality of green sheets are laminated and co-fired at a temperature of 800 to 1000 ° C.

  However, the multilayer ceramic substrate has a problem of causing shrinkage due to sintering in the firing step. Such shrinkage is not uniform, and shrinks due to the inorganic material for the substrate used, the composition of the green sheet, the variation in powder particle size as the raw material, the pattern of the wiring conductor, the material of the wiring conductor arranged inside the board, etc. The rate and shrinkage direction are different.

  In order to reduce this shrinkage rate and non-uniformity in the shrinking direction, a constraining sheet made of alumina that does not sinter at the firing temperature of the glass ceramic component is laminated on both sides or one side of the glass ceramic green sheet laminate and fired. Thereafter, a method of removing the constraining sheet by ultrasonic cleaning, sandblasting, or the like, a so-called non-shrinkage process is performed (see Patent Document 1).

  In addition, since the constraining layer at the end of the substrate is easily peeled in the non-shrink firing, a large warp or deformation occurs at the end of the substrate. For this reason, Patent Document 2 discloses a method of forming a wiring circuit in a region 3 mm or more inside from the peripheral edge.

  Patent Document 3 discloses a method for increasing the first pressure-bonding pressure in the green sheet laminate manufacturing step to be higher than the second pressure-bonding pressure in the step of providing the constraining layer in order to improve the flatness of the substrate. Yes.

International Publication No. WO99 / 55610 JP 2003-249755 A Japanese Patent Laid-Open No. 9-249460

  The conventional method for manufacturing a multilayer ceramic substrate using a non-shrink process has a problem that the end portion of the substrate is easily deformed. In addition, if the product is manufactured by avoiding the deformation region in consideration of the deformation of the end portion, there is a problem that the number of removal is reduced.

  Therefore, the present invention provides a method for manufacturing a multilayer ceramic substrate of low temperature firing (LTCC) that can reduce the deformation region of the substrate end and increase the number of products per substrate in the method of manufacturing a multilayer ceramic substrate, Accordingly, an object of the present invention is to provide a highly reliable multilayer ceramic substrate having high accuracy and high flatness.

  The present invention provides a step of preparing a green sheet made of glass ceramic that can be fired at a low temperature, a step of preparing a constraining sheet using a ceramic slurry mainly composed of an inorganic material that is not sintered at the firing temperature of the green sheet, Of the green sheets, a step of producing a desired conductor pattern with a conductor paste on a desired green sheet, a step of laminating and pressing a green sheet appropriately formed with the conductor pattern to produce a green sheet laminate, and the restraint A step of providing a constraining layer made of a sheet by pressure bonding to the upper and lower surfaces or one side of the green sheet laminate, a step of firing the green sheet laminate provided with the constraining layer at a temperature at which the green sheet sinters, and firing Removing the constraining layer from the green sheet laminate later A method for manufacturing a multilayer ceramic substrate, characterized in that the second pressure bonding condition in providing the constraining layer is equal to or higher than the first pressure bonding condition in the green sheet laminate manufacturing step. . In the step of producing the conductor pattern, a step of forming a via conductor by forming a via hole in a desired green sheet and filling it with a conductor paste may be added.

  The pressure-bonding condition in the manufacturing method of the present invention is pressure, and the second pressure-bonding pressure is set to be equal to or higher than the first pressure-bonding pressure. The pressure bonding condition is temperature, and the second pressure bonding temperature is set to be equal to or higher than the first pressure bonding temperature. Further, the pressure bonding condition is time, and the second pressure bonding time is set to be equal to or longer than the first pressure bonding time.

  The present invention provides a multilayer ceramic substrate comprising a plurality of ceramic layers, a conductor pattern formed on the inside and at least one main surface of the plurality of ceramic layers, and via conductors connecting the conductor patterns to each other. A multilayer ceramic substrate manufactured by the method for manufacturing a multilayer ceramic substrate.

  According to the method for manufacturing a multilayer ceramic substrate according to the present invention, it is possible to obtain a low-temperature fired (LTCC) multilayer ceramic substrate having a high degree of accuracy and high flatness with a small deformation region at the edge of the substrate. And a highly reliable multilayer ceramic substrate having a high level of flatness.

(Function and effect)
The inventor of the present application has scrutinized the deformation of the substrate edge in the method for producing a multilayer ceramic substrate, and found that the adhesion between the constraining layer and the green sheet laminate is a dominant factor. It has been found that the deformation region at the edge of the substrate decreases when the pressure-bonding conditions for pressure-bonding the body, that is, pressure, temperature, and time are increased. The mechanism is presumed as follows. The constraining layer bites into the green sheet laminate by pressure bonding with the green sheet laminate and exerts a restraining force. During firing, the laminate is subjected to a force that tends to shrink, so that a planar force acts at the interface between the constraining layer and the laminate. At this time, since the constraining layer easily peels off at the substrate end, the constraining layer peels off. In the region where the constraining layer is peeled off, deformation occurs because the shrinkage in the planar direction is not suppressed. If the biting of the constraining layer with respect to the green sheet laminate is weak, the constraining layer peels easily due to the force in the planar direction during the firing, and thus the constraining layer peels over a wide area, resulting in a large deformation region. By making the crimping pressure (second crimping) when crimping the constraining layer and the green sheet laminate higher than the crimping pressure (first crimping) when producing the green sheet laminate, Thus, the constraining layer can be strongly entrapped, and the constraining layer is less likely to be peeled off against the force to contract in the planar direction at the time of contraction, so that the deformation region is considered to be reduced. We believe that these pressure requirements are the main conditions, but temperature and time conditions also affect the reduction of deformation area. That is, with respect to the pressure bonding time, the same effect as that obtained when the pressure is increased by increasing the pressure bonding time is obtained, and the deformation region is reduced for the same reason as that. Further, regarding the temperature, the higher the temperature, the softer the binder and plasticizer in the green sheet laminate, and thus the easier the deformation. Since the adhesion between the green sheet laminate and the constraining layer is thought to depend on the microscopic deformation of the laminate or constraining layer, the temperature during the second press bonding should be increased. As a result, the adhesion between the green sheet laminate and the constraining layer is improved, and peeling during firing hardly occurs. As a result, the deformation area is reduced.
As described above, when the method for manufacturing a multilayer ceramic substrate according to the present invention is used, it is possible to manufacture a substrate with a large number of products that can be obtained by reducing the deformation region of the end portion of the substrate.

The present invention will be described below with reference to the drawings.
FIG. 1 is a process diagram showing a method for manufacturing a multilayer ceramic substrate according to the present invention. Here, the following process order is just an example, there is no restriction that the order of the following process is not necessarily, and a plurality of processes may be performed at the same time. In some cases, unnecessary processes are not performed. There is also.

  Now, in the method for manufacturing a multilayer ceramic substrate according to the present invention, the step of preparing a plurality of green sheets 10a, 10b, 10c made of ceramic that can be fired at low temperature is the carrier illustrated in FIGS. 1 (A) and 1 (B). It can be produced by a doctor blade method on the film 5. The production of the plurality of green sheets 10a, 10b, and 10c made of ceramic that can be fired at a low temperature is not limited to the doctor blade method, and may be produced by, for example, a printing method. Hereinafter, the manufacturing process will be described in order.

  FIG. 1A shows a ceramic slurry 1 mainly composed of an inorganic material (for example, alumina) that does not sinter at the firing temperature of the plurality of green sheets 10a, 10b, and 10c on a carrier film 5 with a predetermined thickness by a doctor blade method. The process of apply | coating and forming the restraint sheets 60a and 60b is shown typically. The ceramic slurry 1 is obtained by forming ceramic particles into a slurry (slurry) with a binder and a solvent.

FIG. 1B shows a step of preparing the restraining sheets 60a and 60b by peeling the carrier film 5 after drying.
FIG. 1C shows a step of preparing a plurality of green sheets 10a, 10b, and 10c. However, although the number of layers is three here, the number of layers cannot be specified, and depending on the circuit configuration, ten or more layers may be stacked.
FIG. 1D shows a process of forming via holes 20a and 20b in a plurality of green sheets 10a, 10b, and 10c (all green sheets in this example).
FIG. 1E shows a step of forming via conductors 30a and 30b with a conductive paste in via holes 20a and 20b of desired green sheets 10a, 10b, and 10c among the plurality of green sheets 10a, 10b, and 10c. The process of producing the conductor patterns 40a and 40b with the conductor paste on the surface of the green sheets 10a, 10b, and 10c is shown.
Here, the desired green sheet refers to a green sheet on which the via conductors 30a and 30b and the conductor patterns 40a and 40b are formed as necessary for circuit design of the multilayer ceramic substrate. In the example of FIG. 1E, via conductors 30a and 30b and conductor patterns 40a and 40b are formed on all the green sheets.

FIG. 1 (F) shows a green sheet laminate in which a plurality of green sheets 10a, 10b, and 10c formed with the via conductors 30a and / or conductor patterns 40a are laminated by repeating the press bonding and carrier film peeling steps. The 1st crimping | compression-bonding process which produces 50 is shown.
The process for producing the green sheet laminate 50 will be described in more detail.
First, the green sheet 10a as the surface layer of the multilayer ceramic substrate is set on the fixing film, and is pressed and pressed with a predetermined pressure, temperature and time with an upper mold. The upper and lower molds may have a simple flat plate shape with a built-in heater.
When the press bonding by the press is finished, the carrier film 5 is peeled off. At this time, the green sheet is firmly fixed to the fixing film and is not peeled together when the carrier film 5 is peeled off.

Next, the second green sheet 10b is laminated. On the green sheet, conductor patterns 40c and 40d constituting an internal circuit of a predetermined pattern are printed on the inner layer. The green sheet is set so that the main surface is in contact with the first-layer green sheet 10a, and is pressed and pressure-bonded as in the case of the first-layer green sheet 10a. At this time, if the press temperature is set to a temperature at which the adhesive in the printing paste is softened and fixed, the printing part is bonded to the counterpart green sheet by the applied pressure. Accordingly, the green sheets are joined together via the printing 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 manner as when the electrodes are interposed. Although the pressing temperature depends on the type of 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 pressing force.
After pressure bonding, the carrier film is peeled off. After the third layer 10c, a series of operations similar to those described for the second layer 10b is repeated. Moreover, in order to integrate a laminated body strongly, you may perform a crimping | compression-bonding process further.

In addition, the manufacturing method of the multilayer ceramic substrate which concerns on this invention is not limited to the preparation methods of the above-mentioned green sheet laminated body 50. FIG. That is, in the laminating process, without using a carrier film, a green sheet is stretched on a rigid frame such as stainless steel with light tension maintained, and the rigid frame is handled and printed and laminated. It is also possible to adopt a method of repeatedly applying / drying the ceramic material of the liquid paste as well as the ceramic of any of the above, and the present invention can be applied effectively by using any laminate manufacturing method.
Although not shown in FIG. 1 (F), it is often effective to provide a dividing groove for facilitating the final division after firing after the green sheet laminate 50 is produced.

  FIG. 1 (G) shows constraining sheets 60a and 60b in which alumina particles are bonded with a binder as inorganic materials that are not sintered at the firing temperature of the plurality of green sheets 10a, 10b, and 10c on both sides of the green sheet laminate 50. It is a figure which shows the state laminated | stacked, and it bakes integrally as it is. At this time, what is important is that, in the second pressure-bonding process in which the restraining sheets 60a and 60b are pressure-bonded to the green sheet laminate 50, it is stronger than the pressure-bonding conditions in the first pressure-bonding process in the production of the green sheet laminate 50. Applying proper crimping conditions.

  FIG. 1H shows a step of removing the unsintered restraint sheets 60a and 60b from the fired green sheet laminate 50. Although it shrinks in the stacking direction by firing, it hardly shrinks in the plane. In this way, the wiring patterns of the desired layers are connected, and a three-dimensional circuit can be formed.

As the material composition of the ceramic used for the green sheets 10a, 10b, and 10c in the method for manufacturing a multilayer ceramic substrate according to the present invention, any low-temperature sintered ceramic material that can be co-fired with a conductor paste such as silver, so-called LTCC ceramic, can be used. More preferably, when Al, Si, Sr, and Ti, which are main components, are converted into Al ₂ O ₃ , SiO ₂ , SrO, and TiO ₂ , respectively, 10 to 60% by mass in terms of Al ₂ O _{3 and in} terms of SiO ₂ 25 to 60% by mass, 7.5 to 50% by mass in terms of SrO, 20% by mass or less (including 0) in terms of TiO ₂ , Bi, Na as subcomponents with respect to 100% by mass of the main component , K, and Co, 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, and 0.1 to 5 in terms of K ₂ O It is contained in an amount of 0.1 to 5% by mass in terms of CoO, and at least one of the group of Cu, Mn, and Ag is 0.01 to 5% by mass in terms of CuO and 0.01 in terms of MnO _2. -5% by mass, 0.01 to 5% by mass of Ag, and other inevitable impurities Calcined at 700 ° C. to 850 ° C. The mixture containing a dielectric ceramic composition comprising finely divided particles having an average particle diameter of 0.6~2μm by pulverizing it.
Thereby, the dielectric ceramic composition of the present invention can be integrally sintered using a metal material having a high conductivity such as silver, copper, or gold as an internal electrode. Therefore, according to the present invention, it is possible to configure an electronic component with extremely small loss by using the internal electrode that uses the high Q value of the dielectric material and suppresses the loss due to electric resistance. As a result, a multilayer ceramic substrate with excellent electrical characteristics and low loss can be realized.

  In the method for manufacturing a multilayer ceramic substrate according to the present invention, the material composition of the ceramic used for the constraining sheets 60a, 60b is not fired at the firing temperature (about 800-1000 ° C.) of the LTCC ceramic used for the green sheets 10a, 10b, 10c. However, since various types of alumina can be obtained at low cost, it is common to use alumina.

The production of the green sheets 10a, 10b, 10c, the restraining sheets 60a, 60b and the forming procedure of the restraining sheets in the method for producing a multilayer ceramic substrate according to the present invention will be described.
The green sheets 10a, 10b, and 10c form a dielectric layer of the multilayer ceramic substrate 100. The restraint sheets 60a and 60b restrain the shrinkage in the XY direction only during firing and are removed after firing. Although there are differences and material compositions are different, both are common from the viewpoint of manufacturing green sheets.

In the method for manufacturing a multilayer ceramic substrate according to the present invention, a conventional doctor blade method or the like can be applied to a method for manufacturing a green sheet used for the green sheet laminate 50 and the constraining sheets 60a and 60b. That is, a ceramic slurry made of a dielectric, a binder, and a plasticizer is applied with a uniform thickness on a carrier film such as a polyethylene terephthalate (PET) film by a doctor blade method or the like, and several tens to several hundreds of μm. Green sheets 10a, 10b, and 10c are formed.
The constraining green sheets 60a and 60b are obtained by molding using an organic binder, a plasticizer, a solvent, and the like in the same manner as the production of the ceramic green sheets 10a, 10b, and 10c. As the organic binder, plasticizer, and solvent, the same materials as those used in the ceramic green sheets 10a, 10b, and 10c can be used.

The ceramic slurry contains a binder amount necessary for forming the green sheet. The optimum binder amount varies depending on the particle size and composition of the dielectric, and is not unambiguous and is determined on a case-by-case basis.
If necessary, the dried green sheet is cut into a predetermined size with the carrier film 5 attached.

Next, an internal circuit having a predetermined pattern is printed by screen printing at a predetermined portion that is a product on the main surface that is the opposite surface of the carrier film 5. The printing paste has an Ag powder that acts as a conductor and an adhesive for fixing the Ag powder on the printing surface.
Next, the green sheets are laminated and pressure-bonded in a predetermined order to form a green sheet laminate. Thereafter, a bottom electrode is printed on the bottom surface of the laminate, and a crimping step for more strongly integrating the laminate 50 is performed as necessary, and then further grooved on the upper surface or the lower surface as necessary. After the processing, the constraining sheets 60a and 60b are pressure bonded under pressure bonding conditions stronger than the pressure bonding conditions applied to the production of the laminate 50. Thereafter, the multilayer ceramic substrate is completed by degreasing and firing in a firing furnace.

In FIG. 1, an overcoat (not shown) is formed on the first layer of the multilayer ceramic substrate, that is, on a part of the conductor patterns 40a and 40b of the Ag electrode on the surface layer 10a, and further on a part of the bottom side 40g and 40h. Often provided. Examples of the material for the overcoat include an insulating layer in which an additive component for imparting a function that improves the visibility of the overcoat itself, for example, is added to an alumina-glass low-temperature fired ceramic material. In addition, it is desirable that the sintering shrinkage characteristic and the thermal expansion characteristic approximate to the material of the LTCC ceramic substrate.
By forming an electrode coating region by coating an overcoat on the periphery and a part of the surface conductor patterns 40a, 40b, 40g, and 40h, a multi-layer is provided along with mechanical protection of the surface conductor patterns 40a, 40b, 40g, and 40h. When the ceramic substrate is used, it is possible to prevent the solder provided on the conductive patterns 40a, 40b, 40g, and 40h on the surface layer from flowing out and short-circuiting with an unintended conductive portion. In that case, it is necessary to reduce as much as possible the residual alumina particles of the constraining layer on the overcoat as well as the surface conductive patterns 40a, 40b, 40g, and 40h.

  The green sheet of the low-temperature fired ceramic is not limited to the doctor blade method, and a paste mainly composed of the low-temperature fired ceramic can be produced and applied by a printing means to form a printed layer. In the case of this paste, as compared with the case where the green sheet is formed by the doctor blade method, the selection condition of the organic binder becomes mild, and at least the fluidity can be imparted, and the addition amount can be reduced.

Hereinafter, the manufacturing method of the multilayer ceramic substrate according to the present invention will be described through specific examples.
Using the manufacturing method illustrated in FIG. 1, a green sheet laminate having a thickness of 1.1 mm was produced. Alumina was used as the inorganic material particles constituting the constraining sheets 60a and 60b, and an alumina sheet having a thickness of 0.2 mm was produced.
The surfaces of the constraining sheets 60a and 60b facing the green sheet laminate 50 were laminated on the top and bottom of the green sheet laminate 50 as a contact surface 15A with the PET (polyethylene terephthalate) carrier film 5, and then fired. Thereafter, the restraining sheet was removed by ultrasonic cleaning.

Next, the deformation area evaluation method will be described.
A region where deformation occurs outside the flat portion is defined as a deformation region with respect to a flat surface in which the shrinkage is sufficiently suppressed. As shown in FIG. 2, the size of the deformation area includes a straight line passing through the vertex of a rectangle in contact with the outer periphery of the substrate and forming an angle of 45 ° with one side of the rectangle, and the boundary between the deformation area and the flat portion. And the distance between the intersection and one side of the rectangle is the size of the deformation region. Table 1 shows the size of the deformation region obtained by the above method. The ones marked with an asterisk (*) are comparative examples. The quality of the substrate was judged based on a deformation area size of 2.5 mm or less.

As a result, the smaller the pressure-bonding pressure in the first pressure-bonding step and the larger the pressure-bonding pressure in the second pressure-bonding step, the smaller the deformation region of the substrate end. Further, the shorter the crimping time in the first crimping step, the longer the crimping time in the second crimping step, the smaller the deformation region of the substrate end, and the lower the crimping temperature in the first crimping step, the second The higher the pressure-bonding temperature in the pressure-bonding process, the smaller the deformation area at the edge of the substrate. Regarding the pressure bonding pressure, by making the second pressure bonding pressure equal to or higher than the first pressure bonding pressure, the adhesion between the green sheet laminate and the constraining layer is improved, and with respect to the pressure bonding time, the second pressure bonding time is set to the first pressure bonding time. This is considered to be because the adhesion was improved by making it longer than the pressure bonding time. Regarding the pressure bonding temperature, by increasing the second pressure bonding temperature to be higher than the first pressure bonding temperature, the binder and plasticizer in the green sheet laminate are softened and easily deformed. It is considered that the adhesion of the constraining layer has been improved. From the results of Table 1 above, it was found that the deformation region according to the example can be reduced as compared with the comparative example, and the usable area of the substrate is increased.
Therefore, according to the method for manufacturing a multilayer ceramic substrate according to the present invention, the deformation region is reduced, the usable area is large, the number of products is large, and the low temperature firing (LTCC) with high precision and high flatness is achieved. A method for producing a multilayer ceramic substrate can be provided. As a result, a highly reliable multilayer ceramic substrate having a large area, a large number of products, a high accuracy and high flatness was obtained.

  According to the method for manufacturing a multilayer ceramic substrate and the multilayer ceramic substrate according to the present invention, a high-performance and highly reliable electronic device such as a mobile phone can be realized.

It is process drawing which shows one Example of the manufacturing method of the multilayer ceramic substrate which concerns on this invention. It is the figure which showed the definition method of the magnitude | size of the deformation | transformation area | region of a board | substrate.

Explanation of symbols

1: Ceramic slurry 5: Carrier films 10a, 10b, 10c: Green sheet 15A: Contact surface 15B of green sheet with carrier film 15: Free surface 20a of green sheet ...: Via hole 30a ...: Via conductor (before firing) )
40a ...: Conductor pattern (before firing)
50: Green sheet laminate 60a, 60b: Restraint sheets 70a, 70b, 70c: Ceramic layer 80a ...: Via conductor (after firing)
90a ...: Conductor pattern (after firing)
100: Multilayer ceramic substrate

Claims (5)

Preparing a green sheet made of glass ceramic that can be fired at a low temperature;
Preparing a constraining sheet using a ceramic slurry mainly composed of an inorganic material that is not sintered at the firing temperature of the green sheet;
Of the green sheets, forming a desired conductor pattern with a conductor paste on a desired green sheet;
Laminating a green sheet appropriately formed with the conductor pattern, and a step of producing a green sheet laminate by pressure bonding;
A step of providing a constraining layer of the constraining sheet by pressure bonding to the upper and lower surfaces or one surface of the green sheet laminate;
Firing the green sheet laminate provided with the constraining layer at a temperature at which the green sheet laminate is sintered;
Removing the constraining layer from the green sheet laminate after firing;
A method for producing a multilayer ceramic substrate comprising:
A method for producing a multilayer ceramic substrate, wherein a second pressure bonding condition in the step of providing the constraining layer is equal to or higher than a first pressure bonding condition in the green sheet laminate manufacturing step. 2. The method of manufacturing a multilayer ceramic substrate according to claim 1, wherein the pressure bonding condition is a pressure, and the second pressure bonding pressure is set to be equal to or higher than the first pressure bonding pressure. 3. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the pressure bonding condition is temperature, and the second pressure bonding temperature is equal to or higher than the first pressure bonding temperature. 4. The method of manufacturing a multilayer ceramic substrate according to claim 1, wherein the pressure bonding condition is time, and the second pressure bonding time is set to be equal to or longer than the first pressure bonding time. Multiple ceramic layers;
A conductor pattern formed within the plurality of ceramic layers and on at least one major surface;
Via conductors connecting the conductor patterns;
A multilayer ceramic substrate comprising:
A multilayer ceramic substrate produced by the method for producing a multilayer ceramic substrate according to claim 1.

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