Method of manufacturing ceramic multilayer substrate

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

Low Temperature Co-fired Ceramics (LTCC) technology is a grid Since it enables batch firing of the sheet and metal, various passive elements are placed between the ceramic layers. It is possible to embody a board with a built-in element that incorporates a child. System on Package (SOP) Fruit In the packaging technology, we aimed to combine electronic components and reduce the parasitic effects that occur on surface mount components. Therefore, the manufacturing method related to this element-embedded substrate (hereinafter simply referred to as LTCC multilayer substrate) is diligent. Has been developed.

In the manufacturing method of LTCC multilayer substrate, passive elements and arrangements are applied to each of multiple green sheets. A drawing process for drawing a pattern such as a line and a plurality of green sheets having the pattern are laminated. The crimping step of crimping is carried out in order, and the firing step of batch firing the crimped body is carried out. green In the drawing process of drawing a pattern on a sheet, in order to increase the density of the pattern, conductive a A so-called inkjet method has been proposed in which the ink is ejected as minute droplets (for example). For example, Patent Document 1). The inkjet method uses droplets of several picolitres to several tens of picolitres. Therefore, the pattern should be miniaturized and the pitch should be narrowed by changing the ejection position of the droplets. Can be done.

In the inkjet method, a small droplet is stored inside the nozzle in order to eject it. The gas-liquid interface (meniscus) of the conductive ink is forcibly vibrated. Me formed on the nozzle The meniscus is contained in the conductive ink when the nozzle is kept on standby for a long period of time. Since the dispersion medium continues to volatilize, it causes thickening of the conductive ink and causes poor ejection of droplets. I will end up. On the other hand, if the viscosity of the droplets that land on the green sheet is too low, the green sea Since the droplets wet and spread along the surface of the pattern, it does not hinder the pattern miniaturization and pitch narrowing. I will. Therefore, conductive ink has traditionally been used to prevent drying inside the nozzle. Various dispersion aids added to the dispersion medium to promote drying on the surface of the green sheet Proposed.

For example, sugar alcohols that are solid at room temperature, such as xylitol and arabitol, are sugars. Water system by interaction between alcohol and water, such as hydrogen bonds and van der Waals bonds Drying of the dispersion medium can be suppressed. Also, the interaction between sugar alcohols and conductive microparticles, for example For example, the coordination bond promotes the redispersion of the conductive fine particles once aggregated or precipitated. And Sugar alcohols, which are solid at room temperature, rapidly precipitate as the dispersion medium volatilizes. Excessive wetting and spreading of droplets can be suppressed. For this reason, sugar al that presents as a solid at room temperature Cole is expected as a dispersion aid in water-based conductive inks.<patcit num="1"><text>Japanese Patent Application Laid-Open No. 2005-57139</text></patcit>

<p> However, when using a dispersion aid that is solid at room temperature, the surface of the pattern after drying Since the dispersion aid is deposited on the surface, the adhesion between the pattern and the green sheet is deteriorated. In the end, peeling and migration between the pattern and the ceramic substrate occurred. U.</p><p> The present invention has been made to solve the above problems, and an object thereof is to improve reliability. It is to provide the manufacturing method of the said ceramic multilayer substrate.</p>

<p> In the method for producing a ceramic multilayer substrate of the present invention, a dispersion system of conductive fine particles containing a dispersion aid is liquid. Liquid to each of the green sheets by dropping into each of the plurality of green sheets The step of drawing a pattern and the above by evaporating the dispersion medium from the liquid pattern. A step of forming a drying pattern on each green sheet and the green having the drying pattern. A crimping body is formed by laminating and crimping the sheets, and the crimping body is fired. Therefore, it has a step of forming the ceramic multilayer substrate, dissolves the dispersion aid, and has a step of forming the ceramic multilayer substrate. Before laminating the green sheet, the cleaning liquid that does not dissolve the conductive fine particles is used. Wash the dry pattern.</p><p> In the method for producing a ceramic multilayer substrate of the present invention, a dispersion aid deposited on a drying pattern is used as a cleaning liquid. Since it is washed by cleaning, the adhesion between the pattern and the green sheet can be improved. Shi Therefore, the method for manufacturing a ceramic multilayer substrate described in the present invention is such that the ceramic substrate is peeled off. Reliability of ceramic multilayer boards can be suppressed because migration in internal wiring can be suppressed. Can improve sex.</p><p> In the method for manufacturing this ceramic multilayer substrate, the conductive fine particles are silver fine particles, and the dispersion The medium is a dispersion medium containing water as a main component, the dispersion aid is a sugar alcohol, and the cleaning solution is It may be a cleaning liquid containing water as a main component.</p><p> This ceramic multilayer substrate manufacturing method uses silver fine particles having low migration resistance. Even in this case, the precipitated sugar alcohol is washed with an aqueous cleaning solution, so that it is a pattern. It is possible to improve the miniaturization of the grain and the migration resistance, and by extension, many ceramics. The reliability of the layer substrate can be improved.</p><p> In this method of manufacturing a ceramic multilayer substrate, the green sheet is used before the droplets are ejected. It is preferable to form an adhesion layer that provides adhesion between the surface of the material and the conductive fine particles. In this method of manufacturing a ceramic multilayer substrate, the green sheet is used before the droplets are ejected. It is preferable that the adhesion layer is formed by applying a coupling agent to the surface of the above.</p><p> According to the method for manufacturing a ceramic multilayer substrate, the adhesion layer is a green sheet and conductive fine particles. When cleaning the drying pattern, the drying pattern is peeled off because it provides adhesion between the and the drying pattern. And erosion can be suppressed. Therefore, according to the method for manufacturing this ceramic multilayer substrate, the ceramic The reliability of the multilayer board can be improved more reliably.</p><p> In this method of manufacturing a ceramic multilayer substrate, the liquid powder is prepared before cleaning the drying pattern. By heating the turn, the conductive fine particles contained in the liquid pattern are melted together. You may wear it.</p><p> According to the method for manufacturing this ceramic multilayer substrate, the conductive fine particles contained in the drying pattern are contained. Since they are fused to each other, when cleaning the drying pattern, the drying pattern is peeled off and eroded. , Can be suppressed more reliably. Therefore, according to the method for manufacturing this ceramic multilayer substrate, The reliability can be improved without fail.</p>

(First Embodiment) Hereinafter, the first embodiment embodying the present invention will be described with reference to FIGS. 1 to 7. Figure 1 shows the main train It is a cross-sectional view of a circuit module having a ceramic multilayer board manufactured by using the manufacturing method of Ming. To.

In FIG. 1, the circuit module 10 is a low-temperature firing ceramic as a ceramic multilayer substrate. Low Temperature Co-fired Ceramics (LTCC) Multilayer Board 11 and LTCC Multilayer Group It has a semiconductor chip 12 connected to a plate 11. Each LTCC group of LTCC multilayer board 11 Each of the plates 13 is a sintered body of a green sheet, and is formed with a thickness of several tens of μm to several hundreds of μm. It has been. Between the layers of each LTCC substrate 13, resistance elements, capacitive elements, coil elements, etc. Various internal elements 14 and internal wiring 15 that electrically connects to each internal element 14 are built-in. , Each LTCC substrate 13 has a via arrangement that forms a stack via structure or a thermal via structure, respectively. Line 16 is formed. The internal element 14, the internal wiring 15, and the via wiring 16 are respectively. It is a sintered body of conductive fine particles and is formed by an inkjet method using conductive ink. To.

Next, the manufacturing method of the LTCC multilayer substrate 11 will be described with reference to FIGS. 2 to 7. Figure 2 is L It is a flowchart which shows the manufacturing method of the TCC multilayer board 11, and FIG. 3 is a flow chart in each process. It is a time chart which shows the temperature of a lean sheet. Figures 4 to 7 show LTCC multilayer groups, respectively. It is a process drawing which shows the manufacturing method of a plate 11.

In FIG. 2, in the manufacturing method of the LTCC multilayer substrate 11, it is a precursor of the LTCC substrate 13. A drawing process (step S11) for drawing a liquid pattern on a green sheet and the liquid pattern. A drying step (step S12) of drying the rice is carried out in order. Also, LTCC multilayer group In the manufacturing method of the plate 11, a cleaning step (step S13) for cleaning the dried pattern and a double step are performed. A crimping process (step S14) in which a number of green sheets are laminated and crimped, and a crimped green The firing step (step S15) of firing the sheet is executed in order.

In FIG. 3, the temperatures of the green sheet in the drawing process and the drying process are shown. The drawing temperature is Tp and the drying temperature is Td. The temperature of the sheet is called the cleaning temperature Tw, the crimping temperature Tc, and the firing temperature Ta, respectively. Drawing temperature Tp, drying temperature Td, cleaning temperature Tw, crimping temperature Tc, and baking in this embodiment. The growth temperature Ta is a temperature higher than room temperature (20 ° C).

In FIG. 4, in the drawing process, the carrier film BS and the carrier film BS are coated. A laminated sheet TS composed of the green sheet GS and a droplet ejection device 22 are used. To.

Carrier film BS is a green sheet GS in the drawing process, drying process, and cleaning process. It is a film to support, for example, peelability from green sheet GS and in each process. A plastic film having excellent mechanical resistance can be used. Carrier film B For S, for example, polyethylene terephthalate film, polyethylene naphthalate film, Lum, polyethylene film, polypropylene film can be used.

Green sheet GS is a glass-ceramic set containing glass-ceramic powder, binder, etc. It is a layer consisting of adults. The film thickness of the green sheet GS is the capacitor element as the internal element 14. When forming offspring, it is formed at several tens of μm, and in other layers it is formed at 100 μm to 200 μm. Made.

The surface of the green sheet GS is made of a coupling agent having a thiol group or an amino group. Adhesive layer GSa is applied and formed. The adhesion layer GSa adheres to the conductive fine particles Is. It is a layer that expresses properties and suppresses peeling of a pattern composed of conductive fine particles Is.

The glass-ceramic powder is a powder having an average particle size of 0.1 μm to 5.0 μm, for example. For example, a glass made by mixing borosilicate glass with ceramic powder such as alumina and forsterite. Composite ceramics can be used. As a glass-ceramic powder, ZnO -MgO-Al₂O₃-SiO₂Crystallized glass ceramic using system crystallized glass, B aO-Al₂O₃-SiO₂Ceramic powder and Al₂O₃-CaO-SiO₂-MgO -B₂O₃A non-glass-based ceramic using a based ceramic powder or the like may be used.

The binder has a function as a binder for glass-ceramic powder and is decomposed in the firing process. It is an organic polymer that can be easily removed. As a binder, for example, butyral type, acrylic Binder resins such as type and cellulose type can be used. With acrylic binder resin Then, for example, alkyl (meth) acrylate, alkoxyalkyl (meth) acrylate. G, polyalkylene glycol (meth) acrylate, cycloalkyl (meth) acrylate A homopolymer of a (meth) acrylate compound such as acrylate can be used. Also, Akuri As the binder resin of the ru-based type, a common binder resin obtained from two or more kinds of the (meth) acrylate compounds. Polymers, or other copolymerizable monopolymers such as (meth) acrylate compounds and unsaturated carboxylic acids A copolymer obtained from a dimer can be used. The binder is, for example, adipic acid. Ester plasticizer, dioctyl phthalate (DOP), dibutyl phthalate (DBP) A plasticizer such as a phthalate ester plasticizer or a glycol ester plasticizer may be contained.

A circular hole having a predetermined hole diameter (hereinafter, simply referred to as a positioning hole H) is provided on the edge of the laminated sheet TS. ) Is formed by punching. In each positioning hole H, the position of the mounting plate 21 The placement pin 21P is inserted, and each position of the adhesion layer GSa is positioned with respect to the droplet ejection device 22. Be struck.

The green sheet GS has a thickness of tens of μm to several hundreds of μm by punching or laser machining. Circular holes and conical holes (hereinafter simply referred to as via holes VH) having a hole diameter are formed through. To. For the via hole VH, a squeegee method using a conductive paste or a conductive ink is used. Conductive materials such as silver, gold, copper, and palladium are filled in the previous process by the ink jet method or the like. There is.

The droplet ejection device 22 includes a mounting plate 21 for mounting the laminated sheet TS and a conductive plate 21. The ink tank 23 that stores the ink Ik and the conductive ink Ik of the ink tank 23 are adhered to each other. It has a droplet ejection head 24 for ejecting to GSa.

The mounting plate 21 is a plate material made of a rigid material having substantially the same size as the laminated sheet TS. , The positioning pin 21P for positioning the laminated sheet TS and the laminated sheet TS are heated. Has a heater for 21H. When the laminated sheet TS is placed on the mounting plate 21 , The positioning pin 21P is inserted into the positioning hole H, and the adhesion layer GSa is positioned on the mounting plate 21. It is fixed. Further, when the laminated sheet TS is mounted on the mounting plate 21, the mounting plate 21 is mounted. The rate 21 drives the heater 21H, and the laminated sheet TS is heated to the drawing temperature Tp.

The conductive ink Ik is a conductive fine particle Is in which the conductive fine particle Is is dispersed in the dispersion medium Ia. Dispersion aid Ib, which is a dispersion system and is used to uniformly disperse conductive fine particles Is in the dispersion medium Ia. Including.

Conductive fine particles Is are fine particles having a particle size of several nm to several tens of nm, for example, gold and silver. , Copper, platinum, palladium, rhodium, osmium, ruthenium, iridium, iron, tin, co Metals such as baltic, nickel, chromium, titanium, tantalum, tungsten, indium, etc. Rui or these alloys can be used.

The dispersion medium Ia uniformly disperses the conductive fine particles Is in a system containing the dispersion aid Ib. However, water or an aqueous solution containing water as a main component can be used. Dispersion medium Ia In order to adjust the viscosity of the conductive ink Ik, a water-soluble organic solvent may be contained if necessary. .. Water-soluble organic solvents include, for example, ethanol, methanol, butanol, propanol, Alkyl alcohols such as isopropanol, ethylene glycol monomethyl ether, Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, eth Lenglycol monomethyl ether acetate, propylene glycol monomethylate Glycol ethers such as propylene glycol monoethyl ether, etc. These can be mixed and used.

The dispersion aid Ib is easily dissolved in the dispersion medium Ia and is coordinated with the conductive fine particles Is. It stabilizes the colloidal state of conductive fine particles. Dispersion aid Ib has carboxy It contains a hydroxy acid or a hydroxy salt having a group and a hydroxyl group as functional groups. Hydroki Examples of citric acid include citric acid, malic acid, tartaric acid and the like, and these are mixed and used. Is also good. Hydroxates include sodium citrate, potassium citrate, and lithiu citrate. Sodium malate, sodium tartrate, etc. can be mentioned, and these are mixed and used. You may stay.

Dispersion aid Ib is a polyhydric alcohol with an alcohol valence of 3 to 6 and is in the standard state ( Contains polyhydric alcohols that are solid at 25 ° C and 1 atm). Multivalued arco Alcohol is a sugar alcohol obtained by reducing the carbonyl group of monosaccharides, disaccharides, oligosaccharides and polysaccharides. , 2- (Hydroxymethyl) -1,3-propanediol, 1,2,3-hexaneto Riol, 1,2,3-heptane triol and the like can be used. For sugar alcohol , For example, pentaerythritol, dipentaerythritol, tripentaerythritol , Sorbitol, erythritol, slateol, ribitol, arabitol, xyl Thor, Aritol, Mannitol, Dorsitol, Iditol, Glycol, Inosito Lactitol, maltitol, lactitol, etc. can be mentioned, and a mixture thereof may be used. I.

The concentration of polyhydric alcohol is 5% by weight to 20% by weight based on the total mass of the conductive ink Ik. The amount is%, preferably 10% by weight or more. Polyhydric alcohol concentration is greater than 5% by weight When it becomes low, the moisturizing effect of the dispersion medium Ia by the polyhydric alcohol decreases, and inside the nozzle 26 Insufficient drying control. On the other hand, when the concentration of polyhydric alcohol is higher than 20% by weight , The dispersion of conductive fine particles Is becomes unstable.

When the conductive ink Ik is stored in a predetermined storage chamber, the interaction between the dispersion aid Ib and water For example, hydrogen bonds and van der Waals bonds suppress the evaporation of the dispersion medium Ia. Ma In addition, the interaction between the dispersion aid Ib and the conductive fine particle Is, for example, the coordination bond, is once aggregated. Alternatively, the precipitated conductive fine particles Is are redispersed in the dispersion medium Ia, that is, redispersed. To.

When the conductive ink Ik is ejected as droplets and lands on the object, the conductive fine particles Is Redispersion makes the dry state of the conductive ink Ik uniform, so it depends on the difference in the dry state. Suppress the cracks that occur. Then, from the conductive ink Ik that has landed on the object, the dispersion medium I When a continues to volatilize or evaporate, the dispersion aid Ib is sequentially deposited on the surface of the conductive ink Ik. , The dispersion aid Ib deposited on the object suppresses the wetting and spreading of the conductive ink Ik.

The droplet ejection head 24 has a cavity 25 communicating with the ink tank 23 and a cavity 2. It has a nozzle 26 communicating with 5 and a pressure generating element 27 connected to the cavity 25. The cavity 25 receives the conductive ink Ik from the ink tank 23 and guides the cavity 25 to the nozzle 26. Supply electric ink Ik. The nozzle 26 receives the conductive ink Ik from the ink tank 23. Contain to form a gas-liquid interface, or meniscus. The pressure generating element 27 is the cavity 2 Change the volume of 5 Change the temperature of the piezoelectric element, capacitance element, or cavity 25 It is a resistance heating element and generates a predetermined pressure inside the cavity 25. Pressure generating element 27 When the nozzle 26 is driven, the nozzle 26 vibrates the meniscus of the conductive ink Ik, and the conductive ink Ik is driven. The ink Ik is made into droplets D of several picolitres to several tens of picolitres and discharged.

In FIG. 4, in the drawing process, the laminated sheet TS and the droplet ejection head 24 are in close contact with each other, GSa. A plurality of droplets D ejected from the nozzle 26, which move relative to each other along the surface direction of the By landing on the layer GSa and coalescing, a continuous liquid pattern PL is formed in a predetermined direction. To. In the liquid pattern PL formed on the adhesion layer GSa, the temperature of the green sheet GS is the drawing temperature. Since it is heated to Tp, it receives the amount of heat from the green sheet GS and disperses the dispersion aid Ib in order. By next precipitation, the wet spread can be suppressed.

If the drawing temperature Tp becomes excessively high, the carrier film BS and green sheet GS And will be thermally deformed, and the landing accuracy of the droplet D will be impaired. Therefore, the drawing temperature Tp is For example, at 40 ° C to 80 ° C, a part of the dispersion medium Ia is evaporated on the surface of the liquid pattern PL. It suffices if the temperature is the lower limit that can be achieved, and the laminated sheet can ensure sufficient landing accuracy of the droplet D. A configuration appropriately selected according to the composition of TS and the composition of the conductive ink Ik is preferable.

In FIG. 5, in the drying process, the laminated sheet TS after the drawing process is carried to a drying device such as a drying oven. The green sheet GS having the liquid pattern PL is heated to the drying temperature Td. The drying temperature Td is a temperature for substantially removing the dispersion medium Ia from the liquid pattern PL. To. The state in which the dispersion medium Ia is substantially removed is the state in which the dispersion medium Ia is completely removed (minutes). Regarding the frequency of pattern peeling and the degree of pattern deformation, etc., compared to the state without dispersion Ia) It is in a state where it does not fluctuate. If the drying temperature Td becomes excessively high, the carrier flies. The ilmu BS and the green sheet GS are thermally deformed, and the position accuracy during the crimping process is impaired. It will be lost. Therefore, the drying temperature Td is, for example, 40 ° C to 80 ° C, and the crimping process Depending on the composition of the laminated sheet TS and the composition of the conductive ink Ik so that the position accuracy at the time can be ensured. Therefore, a configuration that is appropriately selected is preferable.

When the green sheet GS is heated to the drying temperature Td, the dispersion contained in the liquid pattern PL The medium Ia is substantially removed. As a result, an aggregate composed of conductive fine particles Is and the aggregate thereof. A dry pattern PD consisting of the dispersion aid Ib deposited on the surface of the coalescence forms on the adhesion layer GSa. Made. The dry pattern PD formed on the adhesion layer GSa is slightly conductive with the adhesion layer GSa. It is fixed to the adhesion layer GSa by the binding force between the particles Is and the cohesive force of the conductive fine particles Is. To.

In FIG. 6, in the cleaning step, the laminated sheet TS after the drying step is carried into the cleaning device and dried. The cleaning liquid 31 is supplied toward the green sheet GS having the dry pattern PD. Cleaning liquid 3 As the supply method of 1, the green sheet GS is immersed in a cleaning tank in which the cleaning liquid 31 circulates. It is also good, or even if the cleaning liquid 31 is constantly sprayed from the cleaning nozzle toward the adhesion layer GSa. good.

The cleaning liquid 31 dissolves the dispersion aid Ib and does not dissolve the conductive fine particles Is. Just do it. As the cleaning liquid 31, water or an aqueous solution containing water as a main component can be used. Wear. The cleaning solution 31 is a water-soluble organic substance as needed to adjust the solubility of the dispersion aid Ib. It may contain a solvent. Water-soluble organic solvents include, for example, ethanol, methanol, butano. Alkyl alcohols such as le, propanol and isopropanol, ethylene glycol Nomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monob Chill ether, ethylene glycol monomethyl ether acetate, propylene glycol Glycol A such as rumonomethyl ether, propylene glycol monoethyl ether, etc. Tells can be mentioned, and these may be mixed and used. In addition, the cleaning liquid 31 is dried. Surfino to improve the permeability to the pattern PD or the cleanability of the dry pattern PD It may be configured to contain a surfactant such as Le (registered trademark). In addition, the conductive ink Ik When using an organic solvent-based ink, the dispersion aid Ib is dissolved and the conductive fine particles I An organic solvent that does not dissolve s may be used as the cleaning liquid 31.

When the cleaning liquid 31 is supplied to the green sheet GS, the dispersion aid deposited on the drying pattern PD Agent Ib elutes into the cleaning solution 31 and is substantially removed from the dry pattern PD. This conclusion As a result, a dry pattern PD composed of conductive fine particles Is is formed on the adhesion layer GSa. this At this time, the drying pattern PD has a binding force between the adhesion layer GSa and the conductive fine particles Is, and the conductive fine particles. Since it is fixed to the adhesion layer GSa due to the cohesive force of the particles Is, it is related to the contact with the cleaning liquid 31. However, the shape can be sufficiently maintained. The dispersion aid Ib has been substantially removed. Compared to the state in which the dispersion aid Ib is completely removed (the state in which the dispersion aid Ib is absent), There is no change in the frequency of turn peeling and the degree of pattern deformation.

In the cleaning process, when the dispersion aid Ib is removed from the drying pattern PD, the laminated sheet TS Is carried into a drying device such as a drying oven, and the green sheet GS having a drying pattern PD is washed. Heated to temperature Tw. The cleaning temperature Tw evaporates the cleaning liquid 31 from the green sheet GS. It is the temperature to remove.

When the green sheet GS is heated to the cleaning temperature Tw, the green sheet GS and the drying pattern The cleaning liquid 31 adhering to the PD evaporates from the green sheet GS and the drying pattern PD. Will be removed.

In FIG. 7, in the crimping process, a base pre for laminating a plurality of green sheet GS. 32, cover plate 33 for pressing multiple green sheet GS, and multiple A vacuum packaging bag 35 for vacuum packaging the green sheet GS is used.

Base plate 32 is a positioning pin 32P that positions multiple green sheet GS. The positioning pin 32P is inserted into the positioning hole H of each green sheet GS. Therefore, each green sheet GS is positioned on the base plate 32. Cover plate 33 has a plurality of insertion holes 33h that allow each positioning pin 32P to be inserted, and has a positioning pin. 32P is inserted into the insertion hole 33h of the cover plate 33, so that multiple grees The laminate 34 made of sheet GS is formed by the base plate 32 and the cover plate 33. Be pinched.

The vacuum packaging bag 35 encloses the base plate 32, the cover plate 33, and the laminate 34. A packaging bag with the flexibility possible. The base plate 32 and the cover plate 33 are laminated. It is housed in a vacuum packaging bag 35 with the body 34 sandwiched between them, and is evacuated by suction using a sealer or the like. It is vacuum-sealed inside the packaging bag 35. The vacuum-sealed laminate 34 is pressed by a predetermined hydrostatic pressure. It is carried into the device and subjected to hydrostatic pressure while being heated to the crimping temperature Tc. Lamination under hydrostatic pressure Since the body 34 isotropically pressurizes almost the entire dry pattern PD, the dry pattern PD While maintaining the shape, crimp between each green sheet GS, and from multiple green sheet GS Form a crimped body.

In the firing step, the crimped body obtained in the crimping step is taken out from the base plate 32 and determined. It is carried into the firing furnace and fired. The firing temperature Ta is, for example, 800 ° C to 1000 ° C. Therefore, it is appropriately changed according to the composition of the green sheet GS. Cu as a drying pattern PD When used, it is preferable to bake in a reducing atmosphere to prevent oxidation. Silver, gold, platinum, When palladium or the like is used, it may be calcined in the atmosphere.

Next, the effects of the first embodiment configured as described above will be described below. (1) The first embodiment dissolves the dispersion aid Ib and does not dissolve the conductive fine particle Is. Clean the drying pattern PD with the cleaning solution 31 before laminating each green sheet GS. .. Therefore, since the dispersion aid Ib deposited on the drying pattern PD can be removed, the drying power can be removed. Adhesion between the turn PD and the laminated green sheet GS can be improved. As a result, It is possible to suppress peeling of the LTCC substrate 13 and migration of the internal wiring 15, and eventually L The reliability of the TCC multilayer board 11 can be improved.

(2) The first embodiment is to apply a coupling agent to the surface of the green sheet GS. Therefore, the adhesion layer GSa that provides adhesion between the green sheet GS and the conductive fine particles Is Form. Therefore, the adhesion layer GSa is between the green sheet GS and the conductive fine particle Is. Since it provides adhesion, the dry pattern PD is peeled off when cleaning the dry pattern PD. And erosion can be suppressed. As a result, the reliability of the LTCC multilayer substrate 11 can be improved more reliably. To.

(Second embodiment) Hereinafter, a second embodiment embodying the present invention will be described with reference to FIGS. 8 and 9. Second embodiment The state is a process changed between the drying step and the washing step in the first embodiment. So Therefore, the changes will be described in detail below.

In FIG. 8, in the manufacturing method of the LTCC multilayer substrate 11, between the drying step and the crimping step, The calcination step (step 12a) is performed. In the present embodiment, the green in the temporary firing step The temperature of the sheet GS is called the calcination temperature Tx (see Fig. 9).

In the temporary firing step, the laminated sheet TS after the drying step is carried into a temporary firing device such as a temporary firing furnace. It is heated to the tentative firing temperature Tx with the drying pattern PD. Temporary firing temperature Tx is conductive A binder contained in the green sheet GS at a temperature at which the sex fine particles Is are fused. It is a temperature lower than the decomposition temperature of.

When the green sheet GS is heated to the temporary firing temperature Tx, the induction contained in the drying pattern PD A part of the electric fine particles Is starts to fuse. As a result, the binding force between the conductive fine particles Is and the drying Since the adhesion between the dry pattern PD and the adhesion layer GSa increases, the dry pattern PD Peeling and erosion can be suppressed more reliably.

If the temporary firing temperature Tx becomes excessively high, the carrier film BS and the green sheet G S is thermally deformed, and the positional accuracy with other laminated sheet TS during the crimping process is impaired. In addition, the binder contained in the green sheet GS starts disassembling. Therefore, the temporary firing temperature Degree Tx is, for example, 80 ° C to 100 ° C, and the position accuracy in the crimping process and the green sheet G Depending on the composition of the laminated sheet TS and the elements of the conductive fine particles Is, so that the adhesion between S can be ensured. Therefore, a configuration that is appropriately selected is preferable.

The above embodiment may be changed as follows. -In the above embodiment, the dispersion medium Ia of the conductive ink Ik is embodied as an aqueous dispersion medium. Not limited to this, the dispersion medium Ia of the conductive ink Ik may be embodied as an organic solvent-based dispersion medium. .. That is, in the present invention, the conductive inn that precipitates the dispersion aid Ib as the dispersion medium Ia evaporates. The dispersion aid Ib deposited on the drying pattern PD may be washed with a cleaning solution using Ik. Just do it.

-In the firing step of the above embodiment, the binder is decomposed and scattered in an oxygen atmosphere, and then dried. A conductive pattern that is oxidized by firing the dry pattern PD in a hydrogen-reducing atmosphere. May be configured to reduce. That is, the present invention describes the temperature, time, atmosphere, etc. of the firing process. It is not limited to.

<figref num="1">Sectional drawing which shows the circuit module.</figref><figref num="2">The flowchart which shows the manufacturing method of a ceramic multilayer substrate.</figref><figref num="3">The figure which shows the temperature of the green sheet in each manufacturing process.</figref><figref num="4">The process drawing which shows the manufacturing method of a ceramic multilayer substrate.</figref><figref num="5">The process drawing which shows the manufacturing method of a ceramic multilayer substrate.</figref><figref num="6">The process drawing which shows the manufacturing method of a ceramic multilayer substrate.</figref><figref num="7">The process drawing which shows the manufacturing method of a ceramic multilayer substrate.</figref><figref num="8">The flowchart which shows the manufacturing method of 2nd Embodiment.</figref><figref num="9">The figure which shows the temperature of the green sheet in each manufacturing process of 2nd Embodiment.</figref>

Code description

D ... Droplet, GS ... Green Sheet, Ia ... Dispersion Medium, Ib ... Dispersion Aid, Ik ... Conductive Inn , Is ... Conductive fine particles, PD ... Dry pattern, PL ... Liquid pattern, 11 ... Ceramic LTCC multilayer boards as multilayer boards, 23 ... green sheets, 31 ... cleaning liquids.