JP6121782B2 - Multilayer ceramic substrate and manufacturing method thereof - Google Patents

Description

The present invention relates to a multilayer ceramic substrate and a manufacturing method thereof .

  As the multilayer ceramic substrate, a low-temperature fired ceramic multilayer substrate (hereinafter, also referred to as “LTCC substrate”. “LTCC” is an abbreviation for Low Temperature Co-fired Ceramics) is known. Since LTCC boards are suitable for modularization and miniaturization, they are widely used in the mobile communication field, the automobile field, and the like. The LTCC substrate is produced by low-temperature firing a laminate of unfired ceramic sheets (green sheets) on which an unfired conductor material mainly composed of silver, copper, gold, or the like is disposed.

  Conventionally, in the firing process of the LTCC substrate, it has been required to match the shrinkage behavior of the laminated ceramic sheets and the shrinkage behavior of the ceramic sheet and the conductor material. Here, the “shrinkage behavior” includes, for example, the timing at which shrinkage begins during firing, the state of time change in size due to shrinkage during firing, the dimensional change rate of the material before and after firing. In the following Patent Documents 1-3, the shrinkage behavior of the material in the firing process is controlled as follows.

  In Patent Document 1, a second green sheet mainly composed of an inorganic composition having a sintering temperature higher than that of the first green sheet is formed on a surface layer of the first green sheet mainly composed of a low-temperature fired substrate material. Be placed. Accordingly, during the first firing performed at a relatively low firing temperature, the second green sheet suppresses the shrinkage of the first green sheet. Further, in the second firing performed at a relatively high firing temperature, the shrinkage of the second green sheet in the surface layer is suppressed by the inner layer that has been sintered during the first firing.

  In Patent Document 2, a first unsintered sheet containing a glass component having a first glass transition point and a second unfired containing a glass component having a second glass transition point that is 80 ° C. lower than the first glass transition point. An unsintered laminated substrate is configured using the binding sheet. In the firing step of Patent Document 2, a first step of firing at a temperature lower than the first glass transition point and higher than the second glass transition point, and a second step of firing at a temperature higher than the first glass transition point. Executed. In the first step, the shrinkage stress of the second green sheet is relaxed by the first green sheet, and in the second step, the shrinkage stress of the first green sheet is relaxed by the second green sheet. .

  In patent document 3, it is comprised by the 1st insulating layer comprised by the 1st inorganic composition, and the 2nd inorganic composition by which the shrinkage | contraction accompanying sintering is started at high temperature rather than a 1st inorganic composition, A second insulating layer having a thickness larger than that of the first insulating layer is alternately stacked to form a stacked body. Further, in the laminate, the shrinkage starts between the first insulating layer and the second insulating layer at a temperature higher than the shrinkage start temperature of the first insulating layer and lower than the shrinkage start temperature of the second insulating layer. A conductor layer is disposed. In Patent Document 3, as the firing process of the laminated body, a heating process for mainly sintering the first insulating layer, a heating process for mainly sintering the conductor layer, and a heating for mainly sintering the second insulating layer. The steps are executed in order.

JP-A-6-97656 JP 2006-245628 A JP 2004-304150 A

  By the way, in the manufacturing process of the LTCC substrate, after firing the laminated substrate having the green sheet and the conductive material, secondary firing is performed in which the unfired material of the electrode and the resistor is disposed on the surface layer of the laminated substrate and fired again. There is a case. In this secondary firing, it is desirable that the dimensional change rate of the laminated substrate before and after the firing and the dimensional change rate of the conductor material disposed on the surface layer coincide with each other. However, although all of the techniques of Patent Documents 1 to 3 described above are considered for controlling the shrinkage behavior of the material in the primary firing, the control of the shrinkage behavior of the material in the secondary firing after the primary firing is not considered at all. It has not been.

  Thus, in the manufacturing process of the LTCC substrate, sufficient control has not been made so far for controlling the shrinkage behavior of the material in the secondary firing. In addition, in the conventional LTCC substrate manufacturing process, there is still room for improvement in controlling the shrinkage behavior of the material in the entire baking process including the primary baking, not limited to the secondary baking. In addition, in the conventional LTCC substrate manufacturing process, it is desired to simplify and simplify the process, reduce the number of processes, reduce costs, save resources, reduce the size of equipment and instruments used, and improve usability. It was rare.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms.

[1] According to one aspect of the present invention, a method for producing a multilayer ceramic substrate is provided. This manufacturing method includes: (a) a first green glass material layer containing a glass material whose main component is non-crystallized glass; and a second green glass containing a glass material whose main component is glass to be crystallized. A plurality of unsintered insulating material layers including a plurality of unsintered insulating material layers, and the outermost layers of the unsintered insulating material layers between the unsintered insulating material layers. And an unsintered wiring material disposed on the surface, and the plurality of unsintered insulating material layers are disposed in through holes penetrating in the thickness direction so as to be connected to the wiring material. A step of preparing an unsintered laminated substrate comprising: an unsintered through electrode material; and (b) a first insulation comprising a glass material mainly composed of glass that is not crystallized by firing the unsintered laminated substrate. Layer and glass material based on crystallized glass A plurality of insulating layers including a plurality of insulating layers, a wiring disposed between the plurality of insulating layers, and an outermost layer surface of the plurality of insulating layers; and the plurality of insulating layers A step of forming a fired laminated substrate comprising a through electrode penetrating each of the layers in the thickness direction; and (c) an unfired resistive material or an unfired electrode material on the surface of the outermost layer of the fired laminated substrate Forming a resistor or an electrode connected to the wiring on the surface of the outermost layer by arranging and firing; and a softening point temperature Ta (° C.) of the non-crystallized glass, The crystallization temperature Tb (° C.) of the crystallized glass satisfies the relationship of Ta ≦ Tb ≦ Ta + 100. According to the manufacturing method of this embodiment, during the firing (primary firing) in the step (b), excessive shrinkage of the first unfired glass material layer is suppressed by the second unfired glass material layer. Further, during the firing (secondary firing) in the step (c), excessive shrinkage of the first insulating layer is suppressed by shrinkage of the second insulating layer.

[2] In the manufacturing method of the above aspect, the crystallization temperature of the glass material to be crystallized may be higher than the firing temperature in the step (c). According to the manufacturing method of this embodiment, excessive shrinkage of the first insulating layer during the secondary firing can be more reliably suppressed.

[3] According to another aspect of the present invention, a multilayer ceramic substrate is provided. The multilayer ceramic substrate includes: a plurality of laminated insulating layers; wirings disposed between the plurality of insulating layers and a surface of the outermost layer of the plurality of insulating layers; and connected to the wirings A plurality of insulating layers, each of the plurality of insulating layers penetrating in the thickness direction; and a resistor or an electrode connected to the wiring on the outermost surface of the plurality of insulating layers. The layer includes at least a first insulating layer containing a glass material whose main component is non-crystallized glass, and a second insulating layer containing a glass material whose main component is crystallized glass; The glass softening point temperature Ta (° C.) and the crystallized glass crystallization temperature Tb (° C.) satisfy the relationship of Ta ≦ Tb ≦ Ta + 100. According to the multilayer ceramic substrate of this embodiment, the shrinkage behavior of the ceramic material and the conductor material in the firing process is appropriately controlled, so that the occurrence of defects due to the material shrinkage in the firing process is suppressed.

[4] In the multilayer ceramic substrate of the above aspect, the total thickness ta of the first insulating layers and the total thickness tb of the second insulating layers satisfy a relationship of tb ≦ ta × 0.1. May be. According to the multilayer ceramic substrate of this embodiment, it is possible to suppress the shrinkage of the second insulating layer from being excessively suppressed by the first insulating layer in the firing step.

  The present invention can also be realized in various forms other than a multilayer ceramic substrate and a method for manufacturing a multilayer ceramic substrate. For example, an unsintered substrate for manufacturing a multilayer ceramic substrate, a method for firing the unsintered substrate, a method for arranging a resistor or an electrode on the outermost layer of the multilayer ceramic substrate, a computer program for realizing these methods, and a computer program therefor Can be realized in the form of a non-temporary recording medium or the like on which is recorded.

Schematic which shows the structure of a LTCC board | substrate. Explanatory drawing which shows the procedure of the manufacturing process of a LTCC board | substrate. The schematic diagram which shows typically the content of each process in the manufacturing process of a LTCC board | substrate. The schematic diagram which shows typically the content of each process in the manufacturing process of a LTCC board | substrate. Schematic which shows the other structural example of a LTCC board | substrate. Schematic which shows the other structural example of a LTCC board | substrate. Explanatory drawing which shows the table | surface which put together the manufacturing conditions and evaluation of the sample of a LTCC board | substrate. Explanatory drawing which shows the procedure of the manufacturing process of the LTCC board | substrate as 2nd Embodiment. The schematic diagram which shows typically the content of each process in the manufacturing process of a LTCC board | substrate. Explanatory drawing which shows the procedure of the manufacturing process of the LTCC board | substrate as 3rd Embodiment. The schematic diagram which shows typically the content of each process in the manufacturing process of a LTCC board | substrate.

A. First embodiment:
FIG. 1 is a schematic view showing a configuration of an LTCC substrate 10 as an embodiment of the present invention. The LTCC substrate 10 is a circuit substrate used for a high-frequency module or IC package used in a computer, a communication device, or the like. The LTCC substrate 10 has a multilayer structure in which a first ceramic insulating layer 1a and a second ceramic insulating layer 1b are laminated. Note that the LTCC substrate 10 of the present embodiment has a five-layer structure, and two first ceramic insulating layers 1a are disposed on both sides of one second ceramic insulating layer 1b.

  Here, the first ceramic insulating layer 1a is composed mainly of glass that is not crystallized in the firing step, and the second ceramic insulating layer 1b is composed mainly of glass that is crystallized in the firing step. ing. In the present specification, the “main component” means a material component that occupies a content of 50% by weight or more of the entire mixture. In the LTCC substrate of the present embodiment, the shrinkage behavior of the material in the firing process is appropriately controlled by having the first and second ceramic insulating layers 1a and 1b. Details thereof will be described later.

  Each ceramic insulating layer 1a, 1b is provided with a through hole 2h (hereinafter also referred to as “via 2h”) penetrating in the thickness direction, and a via electrode 2 is disposed in each via 2h. A wiring pattern 3 is disposed between the ceramic insulating layers 1a and 1b and on the outermost surface. The wiring patterns 3 of each layer are electrically connected through the via electrode 2.

  On the surface of the outermost layer of the LTCC substrate 10, an electrode 5 and a resistor 6 that are electrically connected to the wiring pattern 3 are disposed. Hereinafter, the electrode 5 and the resistor 6 are also particularly referred to as “surface layer electrode 5” and “surface layer resistor 6”. The LTCC substrate 10 of the present embodiment includes primary firing in which the first and second ceramic insulating layers 1a and 1b, the via electrode 2 and the wiring pattern 3 are fired simultaneously, and materials for the surface electrode 5 and the surface resistor 6. And secondary firing for firing. Specifically, it is as follows.

  FIG. 2 is a flowchart showing the procedure of the manufacturing process of the LTCC substrate 10. 3 and 4 are schematic views schematically showing the contents of each step in the manufacturing process of the LTCC substrate 10. In the following description, FIG. 3 is used as a reference diagram for steps S10 and S20 in FIG. 2, and FIG. 4 is used as a reference diagram for steps S30 to S70. In step S10, first and second green sheets 1ag and 1bg, which are unfired ceramic material sheets, are prepared (FIG. 3). The first and second green sheets 1ag and 1bg become the first and second ceramic insulating layers 1a and 1b, respectively, by primary firing.

  Each of the first and second green sheets 1ag and 1bg is produced by forming a ceramic slurry in which ceramic raw material powder, a binder component, a plasticizer, and a solvent are mixed into a sheet by a doctor blade method or the like. Is done. The ceramic raw material powder is a mixed material in which glass powder and an inorganic filler are mixed. Note that the first green sheet 1ag is made mainly of a glass material that is not crystallized in the firing step, and the second green sheet 1bg is made mainly of a glass material that is crystallized in the firing step.

  In step S20, conductor paste, which is an unfired material for the via electrode 2 and the wiring pattern 3, is disposed on each of the green sheets 1ag and 1bg. Specifically, as the conductor paste, a via conductor paste 2g for forming the via electrode 2 and a wiring conductor paste 3g for forming the wiring pattern 3 are prepared. Each of the via conductor paste 2g and the wiring conductor paste 3g is produced by mixing a conductor powder such as silver powder, a glass powder, a binder component, and a solvent.

  The via conductor paste 2g is filled in vias 2h formed on the green sheets 1ag and 1bg by punching. The wiring conductor paste 3g is applied so as to form a predetermined pattern on the surface of each of the green sheets 1ag and 1bg, for example, by screen printing. The green sheets 1ag and 1bg on which the conductor pastes 2g and 3g are arranged are laminated in a predetermined order and are pressed to form an unfired laminated substrate 10g.

  In step S30, the restraint sheets 7 are disposed on both surfaces of the unfired laminated substrate 10g (FIG. 3). The restraint sheet 7 appropriately suppresses the shrinkage of the unfired laminated substrate 10g in the planar direction in the primary firing. The constraining sheet 7 is produced by forming a ceramic raw material powder into a sheet shape, similarly to the first green sheet 1ag. The restraint sheet 7 is removed after the primary firing.

  In step S40, the unfired laminated substrate 10g on which the constraining sheet 7 is disposed is fired (primary firing) at a firing temperature of 1000 ° C. or lower to form the fired laminated substrate 10a. In the primary firing, the shrinkage behavior of both the first and second green sheets 1ag and 1bg is appropriately controlled so as to ensure simultaneous sinterability in which the ceramic material and the conductor material are simultaneously sintered. It is desirable. By ensuring the simultaneous sinterability of the ceramic material and the conductor material, problems such as the generation of voids called voids around the via electrode 2 and the wiring pattern 3 are suppressed.

  In step S50, the electrode paste 5g and the resistance paste 6g, which are unfired materials of the surface layer electrode 5 and the surface layer resistor 6, are disposed on both surfaces of the baked multilayer substrate 10a. In addition, the glass paste for glass-coating the surface resistance body 6 may be further apply | coated to the surface layer of the resistance paste 6g. In step S60, the fired laminated substrate 10a on which the electrode paste 5g and the resistance paste 6g are arranged is fired (secondary firing) again at a firing temperature of 1000 ° C. or less.

  In step S70, as a finishing process, the resistance value of the fired surface layer resistor 6 is adjusted by a laser trimming apparatus or the like. In addition, predetermined parts (illustration and detailed description are omitted) such as IC and chip parts are connected to the surface layer electrode 5 and the like by solder and wires (Au, Cu, Al, etc.). Thereby, the LTCC substrate 10 is completed.

  By the way, even a ceramic insulating layer that has already been fired by primary firing may shrink during the secondary firing. If the ceramic insulating layer shrinks excessively during secondary firing, a difference in dimensional change rate may occur with the surface conductor material, which may cause problems such as poor contact between the surface layer electrode and the surface layer resistance. There is sex. In the secondary firing, even if a restraint sheet for suppressing shrinkage is disposed in the ceramic insulating layer, sufficient bondability is not ensured between the primary fired ceramic insulating layer and the unfired restraint sheet. Therefore, shrinkage of the ceramic insulating layer cannot be sufficiently suppressed.

  However, the LTCC substrate 10 of the present embodiment includes, as a ceramic insulating layer, a first ceramic insulating layer 1a mainly composed of a glass material that is not crystallized in the firing process, and a glass material crystallized in the firing process as a main component. And a second ceramic insulating layer 1b. Since the second ceramic insulating layer 1b is densified by the glass component crystallized in the primary firing, the degree of shrinkage in the secondary firing is higher than that of the first ceramic insulating layer 1a in which the glass component is not crystallized. small. Therefore, in the secondary firing, excessive contraction of the first ceramic insulating layer 1a is suppressed by the second ceramic insulating layer 1b.

Here, the softening point temperature Ta (° C.) of the non-crystallized glass constituting the first ceramic insulating layer 1a and the crystallization temperature Tb (° C.) of the crystallizing glass constituting the second ceramic insulating layer 1b Preferably satisfies the relationship represented by the following inequality (1). The reason for this will be described below.
Ta ≦ Tb ≦ Ta + 100 (1)

  In the firing step of the ceramic insulating layer, the ceramic insulating layer is densified by softening the contained glass and flowing into the voids. Therefore, the firing temperature in the firing step is desirably set to a temperature higher than the softening point temperature so that the glass contained in the ceramic insulating layer flows sufficiently.

  However, if the firing temperature is set to a temperature significantly higher than the softening point temperature of the glass contained in the ceramic insulating layer, the shrinkage of the ceramic insulating layer is promoted, and the shrinkage rates of the ceramic material and the conductor material are shifted. there is a possibility. If the difference in shrinkage speed between the ceramic material and the conductor material is large, the simultaneous sintering of the ceramic material and the conductor material cannot be ensured. Therefore, the firing temperature is desirably set so that the difference from the softening point temperature of the ceramic insulating layer glass is 100 ° C. or less.

Therefore, in the manufacturing process of the LTCC substrate 10 of the present embodiment, the firing temperature T _F1 of the primary firing is at least within the range of the following inequality (2) with respect to the softening point temperature Ta of the first ceramic insulating layer 1a. It is desirable to set.
Ta ≦ T _F1 ≦ Ta + 100 (2)

Here, if the glass crystallization temperature Tb of the second ceramic insulating layer 1b is too low with respect to the firing temperature T _F1 of the primary firing, the second ceramic insulating layer 1b is cured at an early stage in the primary firing. There is a possibility of starting. When the second ceramic insulating layer 1b is hardened, the shrinkage of the first ceramic insulating layer 1a is excessively suppressed by the second ceramic insulating layer 1b, and the simultaneous sinterability with the conductor material cannot be secured. There is a possibility that.

On the other hand, if the crystallization temperature Tb of the glass of the second ceramic insulating layer 1b is too high with respect to the firing temperature T _F1 of the primary firing, the glass of the second ceramic insulating layer 1b is not sufficiently crystallized in the primary firing. There is a possibility. Therefore, in the secondary firing, the shrinkage of the first ceramic insulating layer 1a may not be sufficiently suppressed by the second ceramic insulating layer 1b.

However, if the crystallization temperature Tb of the glass of the second ceramic insulating layer 1b and the softening point temperature Ta of the glass of the first ceramic insulating layer 1a satisfy the relationship of the inequality (1), the crystallization The temperature Tb is suppressed from being significantly different from the firing temperature T _{F1 of the} primary firing. Therefore, the above-described problems are suppressed.

Further, the inventor of the present invention has shown through experiments that in the LTCC substrate 10 of the present embodiment, the thickness ta of the first ceramic insulating layer 1a and the thickness tb of the second ceramic insulating layer 1b are expressed by the following inequality (3 It was found that it is preferable to satisfy the relationship represented by The thicknesses ta and tb mean the total thicknesses of the first and second ceramic insulating layers 1a and 1b included in the LTCC substrate 10, respectively.
tb ≦ ta × 0.1 (3)

  In the second green sheet 1bg constituting the second ceramic insulating layer 1b, the glass crystallizes during the primary firing, so the degree of shrinkage due to firing is the first degree constituting the first ceramic insulating layer 1a. It tends to be larger than the green sheet 1ag. Therefore, during the primary firing, the contraction of the second green sheet 1bg is suppressed by the first green sheet 1ag.

  However, if the thickness tb of the second ceramic insulating layer 1b is too large with respect to the thickness ta of the first ceramic insulating layer 1a, the shrinkage of the second green sheet 1bg is reduced during the primary firing. 1ag may not be sufficiently suppressed. In this case, the second green sheet 1bg may be excessively contracted, and the simultaneous sinterability of the ceramic material and the conductor material may be reduced in the second green sheet 1bg.

  On the other hand, if the thickness ta of the first ceramic insulating layer 1a and the thickness tb of the second ceramic insulating layer 1b satisfy the above relationship, the first and second green sheets 1ag, 1bg The degree of mutual contraction can be appropriately antagonized. Therefore, the shrinkage of the second green sheet 1bg during the primary firing can be appropriately suppressed by the first green sheet 1ag, and the simultaneous sinterability of the ceramic material and the conductor material is suppressed from being lowered.

  The thicknesses ta and tb in the above description are the thicknesses of the ceramic insulating layers 1a and 1b in the completed LTCC substrate 10, respectively. However, the thicknesses ta and tb in the above description may be the thicknesses of the first and second green sheets 1ag and 1bg in the unfired laminated substrate 10g before firing, respectively.

  Furthermore, in the manufacturing process of the LTCC substrate 10 of the present embodiment, it is preferable that the firing temperature in the secondary firing is higher than the crystallization temperature of the crystallizing glass that is the main component of the second ceramic insulating layer 1b. If the firing temperature of the secondary firing is set in this way, the glass of the second ceramic insulating layer 1b can be more reliably crystallized in the secondary firing, and the second ceramic insulating layer 1b can be sufficiently obtained. It can be cured. Therefore, the shrinkage of the first ceramic insulating layer 1a in the secondary firing can be more reliably suppressed by the second ceramic insulating layer 1b.

  5A and 5B are schematic views illustrating another configuration example of the LTCC substrate 10 of the present embodiment. The LTCC substrate 10A of FIG. 5A includes four layers of first ceramic insulating layers 1a and two layers of second ceramic insulating layers 1b. In the LTCC substrate 10A, each of the two second ceramic insulating layers 1b is disposed between the first ceramic insulating layers 1a. As described above, even in the configuration including a plurality of second ceramic insulating layers 1b, the shrinkage behavior of the ceramic material and the conductor material in the primary firing and the secondary firing is similar to the LTCC substrate 10 described in FIG. Appropriately controlled.

  The LTCC substrate 10B shown in FIG. 5B includes three first ceramic insulating layers 1a and one second ceramic insulating layer 1b. In the LTCC substrate 10B, the second ceramic insulating layer 1b is disposed in the outermost layer. Thus, the 2nd ceramic insulating layer 1b does not need to be arrange | positioned between the 1st ceramic insulating layers 1a. Like the LTCC substrate 10B, even if the second ceramic insulating layer 1b is disposed in the outermost layer, the shrinkage of the ceramic material and the conductor material in the primary firing and the secondary firing is the same as the LTCC substrate 10 described in FIG. The behavior is appropriately controlled.

  As described above, the configuration of the LTCC substrate 10 is not limited to the configuration shown in FIG. The LTCC substrate 10 includes at least a first ceramic insulating layer 1a containing a glass material whose main component is glass that is not crystallized in the firing step, and a second material containing a glass material mainly containing the glass that is crystallized in the firing step. And the ceramic insulating layer 1b.

  However, it is desirable that the glass softening point temperature Ta of the first ceramic insulating layer 1a and the glass crystallization temperature Tb of the second ceramic insulating layer 1b satisfy the relationship of the inequality (1) described above. . More preferably, the thicknesses ta and tb of the first and second ceramic insulating layers 1a and 1b satisfy the relationship of the inequality (3) described above. Furthermore, in the manufacturing process, it is preferable that the firing temperature of the secondary firing is higher than the crystallization temperature Tb of the glass of the second ceramic insulating layer 1b.

  FIG. 6 is an explanatory diagram showing a table summarizing the manufacturing conditions and evaluation of the LTCC substrate sample produced by the inventors of the present invention. The inventor of the present invention produced samples T1 to T10 of a multilayered LTCC substrate having first and second ceramic insulating layers made of different materials and evaluated them. Specific manufacturing conditions and evaluation results for each of the samples T1 to T10 are as follows.

1. Manufacturing conditions:
<First green sheet>
A first green sheet constituting the first ceramic insulating layer was produced as follows. In addition, the 1st green sheet was common in each sample T1-T10, and the softening point temperature was 758 degreeC.

[1] Material:
(1) Glass powder (glass material not crystallized): Borosilicate glass powder mainly composed of silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and boron oxide (B ₂ O ₃ ) (2) Inorganic filler: Alumina powder (average particle size 3 μm, specific surface area 1.8 m ² / g)
(3) Binder component: Acrylic binder (4) Plastic content: Dioctyl phthalate (DOP)
(5) Solvent: Methyl ethyl ketone (MEK)

[2] Manufacturing method:
(1) Borosilicate glass powder and alumina powder were weighed so as to have a volume ratio of 60:40 (total amount: 1 kg), and charged into an alumina pot.
(2) An acrylic resin (120 g) and MEK and DOP (amount capable of securing a desired slurry viscosity and sheet strength) were further charged into an alumina pot.
(3) The above materials put in an alumina pot were mixed for 5 hours to obtain a ceramic slurry.
(4) Using the ceramic slurry, a green sheet having a thickness of 0.15 mm was produced by a doctor blade method.

<Second green sheet>
A second green sheet constituting the second ceramic insulating layer was produced as follows. In addition, the following glass powder prepared for each sample T1-T10. As the glass powder for samples T1 to T8, one whose composition was adjusted so that the crystallization temperature was different for each sample was used. Glass powders for samples T9 and T10 whose composition was adjusted to be amorphous were used.

[1] Material:
(1) Glass powder (glass material to be crystallized): barium borosilicate mainly composed of silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ), barium oxide (BaO) Acid-based glass powder (2) Inorganic filler: Alumina powder (average particle size 3 μm, specific surface area 1.8 m ² / g)
(3) Binder component: Acrylic binder (4) Plastic content: Dioctyl phthalate (DOP)
(5) Solvent: Methyl ethyl ketone (MEK)

[2] Manufacturing method:
(1) Barium borosilicate glass powder and alumina powder were weighed so that the volume ratio was 60:40 (only sample T3 was 65:35) (total amount: 1 kg), and charged into an alumina pot.
(2) An acrylic resin (120 g) and MEK and DOP (amount capable of securing a desired slurry viscosity and sheet strength) were further charged into an alumina pot.
(3) The above materials put in an alumina pot were mixed for 5 hours to obtain a ceramic slurry.
(4) Using the ceramic slurry, a second green sheet having a thickness of 0.05 mm was produced by a doctor blade method.

<Wiring conductor paste>
A wiring conductor paste was made of the following materials.
[1] Material:
(1) Silver powder (average particle size 0.9 μm)
(2) Borosilicate glass (softening point temperature 700 ° C)
(3) Resin, organic solvent: ethyl cellulose resin, terpineol [2] Production method:
Borosilicate glass (2 parts by weight) was added to silver powder (100 parts by weight), and ethyl cellulose resin and terpineol were further added and kneaded by a three-roll mill.

<Via conductor paste>
A via conductor paste was made of the following materials.
[1] Material:
(1) Silver powder (average particle size 3.5 μm)
(2) Borosilicate glass (softening point temperature 800 ° C)
(3) Resin, organic solvent: ethyl cellulose resin, terpineol [2]
It was prepared by adding 5 parts by weight of borosilicate glass to 100 parts by weight of silver powder, adding ethyl cellulose resin and terpineol, and kneading with a three-roll mill.

<Unfired laminated substrate>
(1) A via was formed in each green sheet sample and filled with a via conductor paste. In addition, a wiring pattern was formed on each green sheet sample using a wiring conductor paste.
(2) The first green sheet sample (four layers) and the second green sheet sample (one layer) are stacked in combination to produce samples T1 to T10 of an unfired laminated substrate having a thickness of 0.65 mm. did.

<Restraining sheet>
In the primary firing, a constraining sheet to be arranged on the surface layer of each sample T1 to T10 of the unfired laminated substrate was produced. The constraining sheet was produced with a thickness of 0.30 mm by the same manufacturing method as the first green sheet, except that only alumina powder was used as the ceramic raw material powder.

<Primary firing>
A restraint sheet was disposed on the surface layer of each sample T1 to T10 of the unfired laminated substrate, and primary firing was performed under the following conditions.
(1) Firing temperature: 850 ° C
(2) Firing time: 30 minutes (3) Load (applied in the stacking direction): 0.2 MPa

<Secondary firing>
After removing the restraint sheet from each sample T1 to T10 of the fired laminated substrate after the primary firing, a resistance paste was applied to each surface layer, and secondary firing was performed under the following conditions.
(1) Firing temperature: 850 ° C
(2) Firing time: 30 minutes

2. Evaluation results:
<Board evaluation>
Before the primary firing, holes for measuring dimensions (diameter 0.5 mm) are formed at predetermined pitches of 100 mm on the substrate surface of each sample T1 to T10 at a pitch of 100 mm, and the pitch is measured after the secondary firing. The dimensional change rate in the planar direction before the primary firing and after the secondary firing was calculated. Further, the state of the substrate around the conductor (via electrode, wiring pattern, surface layer resistor) was observed and evaluated.

[1] Samples T1 to T5 In samples T1 to T5, the second ceramic insulating layer was mainly composed of glass that crystallizes in the firing step. The crystallization temperature of the glass of the second ceramic insulating layer was higher than the softening point temperature of the glass of the first ceramic insulating layer, and the difference from the softening point temperature was 100 ° C. or less. Therefore, the dimensional change rates of the samples T1 to T5 were all 0.05 or less, which was good. Also, no defects such as voids occurred around the conductor.

  Here, in the samples T2 and T3, in which the crystallization temperature of the glass of the second ceramic insulating layer is higher by 5 ° C. or more than the secondary firing temperature, the dimensional change rate was significantly smaller than in the samples T1, T4, and T5. Specifically, in samples T2 and T3, the dimensional change rate was smaller than 0.02. This is considered to be because glass crystallization of the second insulating ceramic insulating layer was promoted in the secondary firing.

[2] Samples T6 and T7 In samples T6 and T7, the crystallization temperature of the glass of the second ceramic insulating layer is 100 ° C. or higher than the softening point temperature of the glass of the first ceramic insulating layer. It was higher by 50 ° C. than the firing temperature of the secondary firing. In samples T6 and T7, the dimensional change rate exceeded 0.4, which was remarkably large. This is presumably because the glass of the second ceramic insulating layer was not sufficiently crystallized in the primary firing, and the shrinkage of the first ceramic insulating layer was not sufficiently suppressed in the secondary firing.

[3] Sample T8 In sample T8, the crystallization temperature of the glass of the second ceramic insulating layer was 50 ° C. or more lower than the softening point temperature of the glass of the first ceramic insulating layer. In sample T8, the dimensional change rate exceeded 0.05, and voids were generated around the conductor. This is because the crystallization temperature of the glass of the second green sheet was too low with respect to the firing temperature of the primary firing, so that the glass of the second green sheet crystallized early during the primary firing, and the ceramic material and This is thought to be because the shrinkage behavior of the conductor material has deviated.

[4] Samples T9 and T10 In samples T9 and T10, the glass component of the second ceramic insulating layer did not have a crystallized glass as a main component. In Samples T9 and T10, the dimensional change rate exceeded 0.5 and was significantly increased. This is presumably because the second ceramic insulating layer did not contain crystallized glass, and thus the shrinkage of the first ceramic insulating layer was not sufficiently suppressed in the secondary firing.

  As described above, according to the LTCC substrate 10 of the present embodiment and the manufacturing process thereof, the shrinkage behavior of the ceramic material and the conductor material in the primary firing and the secondary firing is appropriately controlled. Therefore, generation | occurrence | production of the malfunction accompanying the shrinkage | contraction of the material in a baking process is suppressed.

B. Second embodiment:
FIG. 7 is a flowchart showing the procedure of the manufacturing process of the LTCC substrate as the second embodiment of the present invention. The manufacturing process of the second embodiment is the same as the manufacturing process (FIG. 2) described in the first embodiment, except that the processes of steps S11 and S12 are executed instead of the process of step S10. FIG. 8 is a schematic diagram similar to FIG. 3 and shows the process contents of steps S11 to S20. Below, each process of step S11-S20 of FIG. 7 is demonstrated using FIG. 8 as a reference figure.

  In step S11, a first green sheet 1ag constituting the first ceramic insulating layer 1a is prepared. The first green sheet 1ag is produced by the same method as described in the first embodiment. In step S12, a second green sheet 1bg constituting the second ceramic insulating layer 1b is prepared.

  In the manufacturing process of the second embodiment, the second green sheet 1bg is produced by applying an insulator paste to the surface of one appropriately selected from the first green sheets 1ag produced in step S11. . Hereinafter, the integrally formed first and second green sheets 1ag and 1bg are also referred to as “union green sheet 1cg”. The insulator paste is an unfired ceramic material obtained by kneading a ceramic raw material powder in which glass powder and an inorganic filler are mixed, a binder component, a plasticizer, and a solvent into a paste. More specifically, the insulating paste is obtained by the following manufacturing method.

<Insulation paste>
[1] Material:
(1) Glass powder (crystallized glass): barium borosilicate mainly composed of silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), boron oxide (B ₂ O ₃ ), and barium oxide (BaO) Glass powder (2) Inorganic filler: Alumina powder (average particle size 3 μm, specific surface area 1.8 m ² / g)
(3) Resin, organic solvent: ethyl cellulose resin, terpineol [2]
Borosilicate glass powder and alumina powder are mixed at a weight ratio of 65:35, ethyl cellulose resin and terpineol are added, and the mixture is kneaded by a three-roll mill.

  In step S20, the conductor pastes 2g and 3g are arranged on the first green sheet 1ag produced in step S11 and the combined green sheet 1cg produced in step S12. The conductor pastes 2g and 3g are the same as those described in the first embodiment, and the arrangement method thereof is the same as that described in the first embodiment. In step S20, the first green sheet 1ag and the combined green sheet 1cg on which the conductor pastes 2g and 3g are arranged are further laminated and pressure-bonded in a predetermined order, thereby producing an unfired laminated substrate 10gC. In addition, since the process after step S30 is the same as the process demonstrated in 1st Embodiment, the description is abbreviate | omitted.

  As described above, even in the manufacturing process of the second embodiment, an LTCC substrate having the first and second ceramic insulating layers can be manufactured. In the manufacturing process of the second embodiment, since the second green sheet 1bg is formed while being supported by the first green sheet 1ag, the second green sheet 1bg can be thinned. . Therefore, the second ceramic insulating layer 1b can be thinned.

C. Third embodiment:
FIG. 9 is a flowchart showing the procedure of the manufacturing process of the LTCC substrate as the third embodiment of the present invention. The manufacturing process of the third embodiment is the same as the manufacturing process (FIG. 2) described in the second embodiment, except that the processes of steps S21 to S23 are executed instead of the processes of steps S12 and S20. FIG. 10 is a schematic diagram similar to FIG. 8 and shows the process contents of steps S11 to S23. Below, each process of step S11-S23 of FIG. 9 is demonstrated using FIG. 10 as a reference figure.

  In step S11, the first green sheet 1ag constituting the first ceramic insulating layer 1a is produced by the same method as described in the first embodiment. In step S21, conductor pastes 2g and 3g are arranged on each of the first green sheets 1ag produced in step S11. The conductor pastes 2g and 3g are the same as those described in the first embodiment, and the arrangement method thereof is the same as that described in the first embodiment.

  In step S22, an insulating paste is applied to the surface of the first green sheet 1ag appropriately selected from the first green sheets 1ag on which the conductor pastes 2g and 3g are arranged in step S21 to produce the second green sheet 1bg. The insulating paste is the same as that described in the second embodiment. Hereinafter, the sheet in which the first and second green sheets 1ag and 1bg are integrated in this process is also referred to as “union green sheet 1dg”.

  In step S22, the insulating paste is applied in consideration of the conductive path so that the electrical continuity between the wiring patterns arranged between the ceramic insulating layers is not inhibited in the completed LTCC substrate. For example, as shown in FIG. 10, the insulating paste may be applied around the wiring conductor paste 3g disposed on the surface of the first green sheet 1ag.

  In step S23, the first green sheet 1ag on which the conductor pastes 2g and 3g are arranged in step S21 and the united green sheet 1dg in step S22 are laminated and pressure-bonded in a predetermined order, whereby an unfired laminated substrate is obtained. 10 gD is made. In addition, since the process after step S30 is the same as the process demonstrated in 1st Embodiment, the description is abbreviate | omitted.

  As described above, even in the manufacturing process of the third embodiment, the LTCC substrate having the first and second ceramic insulating layers 1a and 1b can be manufactured. Also in the manufacturing process of the third embodiment, the second ceramic insulating layer 1b can be thinned as in the manufacturing process of the second embodiment.

D. Variations:
D1. Modification 1:
In each of the above embodiments, after the primary firing, the unfired materials of the surface layer electrode 5 and the surface layer resistor 6 are disposed in the outermost layer of the fired laminated substrate 10a (step S50 in FIG. 2). However, after the primary firing, the unfired materials of both the surface layer electrode 5 and the surface layer resistor 6 may not be disposed in the outermost layer of the fired laminated substrate 10a. Any one of the unfired materials may be disposed. For example, the unfired material of the surface layer electrode 5 may be disposed in the outermost layer of the unfired laminated substrate 10g before the primary firing.

D2. Modification 2:
In the said embodiment, the restraint sheet | seat 7 was arrange | positioned on both surfaces of the unbaking laminated substrate 10g before primary baking. However, the use of the restraining sheet 7 in the primary firing may be omitted. However, if the restraint sheet 7 is used in the primary firing, the shrinkage in firing the LTCC substrate 10 can be controlled more appropriately.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 1a ... 1st ceramic insulating layer 1ag ... 1st green sheet 1b ... 2nd ceramic insulating layer 1bg ... 2nd green sheet 1cg ... Combined green sheet 1dg ... Combined green sheet 2 ... Via electrode 2g ... Via conductor paste 2h ... via 3 ... wiring pattern 3g ... wiring conductor paste 5 ... surface layer electrode 5g ... electrode paste 6 ... surface layer resistor 6g ... resistance paste 7 ... restraint sheet 10, 10A, 10B ... LTCC substrate 10a ... fired laminated substrate 10g, 10gC, 10gD ... Unfired laminated substrate

Claims (3)

A method for producing a multilayer ceramic substrate, comprising:
(A) a first green glass material layer including a glass material mainly containing non-crystallized glass; and a second green glass material layer including a glass material mainly containing glass to be crystallized. A non-fired laminated substrate in which a plurality of unfired insulating material layers are laminated,
An unsintered wiring material disposed between the unsintered insulating material layers and a surface of the outermost layer of the unsintered insulating material layers,
An unfired through-electrode material disposed in a through-hole penetrating each of the unfired insulating material layers in the thickness direction so as to be connected to the wiring material;
Preparing a green laminate substrate comprising:
(B) firing the green laminate substrate;
A plurality of insulating layers including: a first insulating layer containing a glass material mainly containing non-crystallized glass; and a second insulating layer containing a glass material mainly containing crystallized glass;
Wiring disposed between the plurality of insulating layers and on the outermost surface of the plurality of insulating layers;
A through electrode penetrating each of the plurality of insulating layers in the thickness direction;
Forming a fired laminated substrate comprising:
(C) A resistor or an electrode connected to the wiring on the surface of the outermost layer is formed by disposing an unfired resistive material or an unfired electrode material on the surface of the outermost layer of the fired multilayer substrate and firing it. Forming, and
With
The softening point temperature Ta (° C.) of the non-crystallized glass and the crystallization temperature Tb (° C.) of the crystallized glass are:
Ta ≦ Tb ≦ Ta + 100
Meet the relationship,
The total thickness ta of the first insulating layer after firing and the total thickness tb of the second insulating layer after firing are:
tb ≦ ta × 0.1
A manufacturing method characterized by satisfying the relationship : The manufacturing method according to claim 1,
The crystallization temperature of the glass material to crystallize is a manufacturing method higher than the firing temperature in the step (c). A plurality of laminated insulating layers;
Wiring disposed between the plurality of insulating layers and on the outermost surface of the plurality of insulating layers;
A through electrode connected to the wiring and penetrating each of the plurality of insulating layers in the thickness direction;
A resistor or an electrode connected to the wiring on the surface of the outermost layer of the plurality of insulating layers;
In a multilayer ceramic substrate comprising:
The plurality of insulating layers are at least
A first insulating layer containing a glass material mainly composed of non-crystallized glass;
A second insulating layer containing a glass material mainly containing crystallized glass;
Including
The softening point temperature Ta (° C.) of the non-crystallized glass and the crystallization temperature Tb (° C.) of the crystallized glass are:
Ta ≦ Tb ≦ Ta + 100
Meet the relationship,
The total thickness ta of the first insulating layer and the total thickness tb of the second insulating layer are:
tb ≦ ta × 0.1
Characterized Succoth meet the relationship, the multilayer ceramic substrate.

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