JP2005203810A - Manufacturing method for ceramic multi-layer substrate, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture ceramic multi-layer substrate having cavities with superior dimensional accuracy, without convexly warping the bottom surface of the cavity. <P>SOLUTION: On both surfaces of a previously sintered substrate 12, a plurality of unsintered low temperature sintering ceramic green sheets 13 in each of which an opening 14a for forming cavity is formed are laminated and thermo-compression-bonded to form a laminate. Then constraining green sheets 15 formed of high temperature sintering ceramics which are not sintered at sintering temperatures of the low temperature sintering ceramic green sheets 13 are laminated on both surfaces of the laminate and thermo-compression-bonded. In this state, while pressurizing by the constraining green sheet 15, or without pressurizing, sintering is performed at 800-1,000°C that is the sintering temperature of the low temperature sintering ceramic green sheet 13. After sintering, residues (ceramic fine particle) of the constraining green sheets 15 stuck to both surfaces of a sintered substrate 11 are removed by blasting or buffing, etc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a ceramic multilayer substrate and a semiconductor device in which a ceramic multilayer substrate is manufactured by laminating unfired ceramic green sheets on both surfaces of a previously fired ceramic substrate.

  In general, a ceramic multilayer substrate is often manufactured by a green sheet lamination method. In this green sheet laminating method, via holes are formed in a plurality of ceramic green sheets, and via conductors are formed by filling the via holes in each ceramic green sheet to form via conductors. To print. Thereafter, the plurality of ceramic green sheets are laminated and thermocompression bonded to produce a green substrate, and then the green substrate is baked to produce a ceramic multilayer substrate.

JP 2001-267743 A Japanese National Patent Publication No. 5-503498 Japanese Patent Laid-Open No. 9-92983

  However, since baking shrinkage of about 15 to 30% occurs in the process of firing the raw substrate, it is difficult to manage the dimensional accuracy of the substrate, and in addition, the shrinkage of both sides of the substrate is difficult in a multilayer substrate with unevenness such as a cavity. Since the stress becomes non-uniform, the fired substrate is likely to be warped, and in particular, the bottom surface of the cavity has a large warp.

  In the case of firing a composite ceramic multilayer substrate by laminating an insulating ceramic green sheet and a ceramic green sheet of a different material such as a dielectric or magnetic body, the sintering temperatures of the two are matched, and both Since it is necessary to reduce the difference in the firing shrinkage behavior of each layer to prevent delamination, there are disadvantages that the range of material selection is very narrow and the degree of design freedom is very narrow.

  In recent years, as a firing method for reducing firing shrinkage of a substrate and improving substrate dimensional accuracy, as shown in Patent Document 1, an unfired ceramic green sheet in which a wiring pattern is printed in advance on a fired alumina substrate is used. It has been proposed to produce a ceramic multilayer substrate by laminating and thermocompression bonding and firing the laminate. This firing method is intended to reduce the firing shrinkage of the entire substrate by restraining the firing shrinkage of the ceramic green sheet with the fired alumina substrate.

  However, as is clear from the experimental results of the inventor to be described later, since the firing shrinkage force of the ceramic green sheet is large, even if it is attempted to restrain firing shrinkage of the ceramic green sheet from only one side of the fired alumina substrate, it is sufficiently suppressed. I can't. As a result, peeling may occur between the fired layer of the ceramic green sheet and the fired alumina substrate, cracks may be generated in the fired layer of the ceramic green sheet, and warping of the substrate may occur. There is a disadvantage that the yield is poor.

  Further, as a firing method having a large effect of improving the substrate dimensional accuracy by reducing the firing shrinkage of the substrate, a pressure firing method has been developed as shown in Patent Document 2 and Patent Document 3, for example. In this pressure firing method, constraining alumina green sheets that are not sintered at the sintering temperature (800 to 1000 ° C.) of the low-temperature fired ceramic are laminated on both sides of the low-temperature fired ceramic substrate (hereinafter referred to as “raw substrate”) before firing. In this state, the green substrate is baked at 800 to 1000 ° C. while pressing the raw substrate, and then the residual alumina green sheet for restraint is removed from both sides of the baked substrate by blasting or the like to produce a low-temperature fired ceramic substrate. .

  However, when a low-temperature fired ceramic substrate with a cavity is fired by the above-mentioned pressure firing method, the pressure applied to the cavity region via the constraining alumina green sheet acts intensively on the cavity periphery, and on the bottom surface of the cavity Since the applied pressure does not act at all, the bottom surface of the cavity is warped in a convex shape, and there is a drawback that the dimensional accuracy of the cavity cannot be ensured.

  The present invention has been made in consideration of these circumstances, and the first object is to greatly increase the degree of freedom of material selection with respect to the sintering temperature, firing shrinkage characteristics, etc. of the ceramic material forming each layer of the ceramic multilayer substrate. A ceramic multilayer substrate having a configuration that can be enlarged and difficult to manufacture by a conventional manufacturing method is capable of being manufactured with high dimensional accuracy without delamination or warping. This is to make it possible to manufacture a ceramic multilayer substrate with cavities with high dimensional accuracy without causing the bottom surface of the cavity to warp in a convex shape.

  In order to achieve the first object, a method for producing a ceramic multilayer substrate according to claim 1 of the present invention is characterized in that the fired substrate is baked on both surfaces of a previously fired ceramic substrate (hereinafter referred to as “fired substrate”). A laminated body is formed by laminating one or a plurality of unfired ceramic green sheets formed of a ceramic material different from the fired substrate sintered at a temperature substantially equal to or lower than the sintering temperature. A step of producing, and a step of laminating a green sheet for restraint that does not sinter at the sintering temperature of the unfired ceramic green sheet on both sides of the unfired ceramic green sheet laminated on the outermost layer of the laminate, , Restraint firing at the sintering temperature of the green ceramic green sheet with or without pressurization of the laminate through the restraining green sheet It is characterized in that comprises to a constraint firing step of integrating the laminate, and removing the constraining green sheet remnants after the constraint firing step.

  In short, the present invention produces a laminate by laminating an unfired ceramic green sheet formed of a ceramic material different from the fired substrate on both sides of the fired substrate, and the restraint green is formed on the laminate. The most significant feature is that the sheets are laminated and subjected to restraint firing (pressure firing or pressureless firing). In this way, firing shrinkage, warpage, and deformation in the X and Y directions of the unfired ceramic green sheet during restraint firing can be suppressed almost uniformly by the restraining green sheet and the fired substrate from both sides, and dimensional accuracy And a ceramic multilayer substrate free from delamination or warpage can be manufactured. In this manufacturing method, the difference in sintering temperature between the fired substrate and the unfired ceramic green sheet, the difference in firing shrinkage characteristics, etc. are not a problem, so the ceramic material that forms each layer of the ceramic multilayer substrate is sintered. The degree of freedom of material selection with respect to temperature, firing shrinkage characteristics, etc. can be greatly expanded, and a multilayer ceramic substrate with a structure that has been difficult to manufacture with conventional manufacturing methods can be dimensionally accurate without delamination or warping. Can be manufactured.

  In addition, since the fired substrate and the unfired ceramic green sheet are formed of different ceramic materials, a composite ceramic multilayer substrate containing various functional materials, which has been difficult to manufacture by conventional manufacturing methods, is manufactured. be able to.

  In this case, in the step of laminating the unfired ceramic green sheet on the fired substrate, both may be simply overlapped. This is because the ceramic green sheet and the fired substrate are thermocompression-bonded when the laminate is pressed and heated in the subsequent steps without being temporarily fixed by crimping or the like during lamination.

  However, in general, as in claim 2, in the step of laminating an unfired ceramic green sheet on a fired substrate, it is preferable to temporarily fix both of them by, for example, thermocompression bonding or an adhesive. In this way, when handling the laminated body in the subsequent process, there is no fear of displacement between the fired substrate and the unfired ceramic green sheet, the handling of the laminated body is easy, and the ceramic Adhesion between the green sheet and the baked substrate can be improved, and delamination or warpage between the two can be more reliably prevented.

  Further, in the step of laminating the constraining green sheet on the unfired ceramic green sheet laminated on the outermost layer of the laminate, both may be simply overlapped. This is because even if both are not pressure-bonded at the time of lamination, if they are subsequently fired under pressure, both are pressure-heated and heat-bonded.

  However, in general, as in claim 3, it is preferable to temporarily fix the constraining green sheet in the step of laminating the green ceramic green sheet laminated on the outermost layer of the laminate. In this way, even when firing without pressure, a restraining force can be exerted on the unfired ceramic green sheet from the restraining green sheet, which is difficult to manufacture with the conventional manufacturing method. The ceramic multilayer substrate can be manufactured with high dimensional accuracy without delamination or warping.

  In this case, as described in claim 4, it is preferable to use an unfired ceramic green sheet formed of a low-temperature fired ceramic material fired at 1000 ° C. or lower. In this way, as a constraining green sheet, it is possible to use a ceramic that is relatively inexpensive and excellent in mechanical strength, such as an alumina green sheet, and as a wiring conductor that is printed on an unfired ceramic green sheet, A low melting point metal such as an Ag-based, Au-based, or Cu-based material having a small electrical resistance value and excellent electrical characteristics can be used.

  In addition, as described in claim 5, the fired substrate and / or the unfired ceramic green sheet may be formed of a ceramic having any one of functions of insulating, dielectric, magnetic, piezoelectric, and resistive. Here, the insulating ceramic is a ceramic used to form the insulating layer of the substrate, and examples thereof include a low-temperature fired ceramic and a high-temperature sinterable ceramic such as alumina. Since the fired substrate is fired by itself, all kinds of ceramics can be used, and an unfired ceramic green sheet is formed using a ceramic material that is sintered at a temperature lower than the sintering temperature of the fired substrate. Just do it.

  In order to achieve the second object, as in the case of manufacturing a ceramic multilayer substrate with a cavity as in claim 6, the fired substrate is positioned on the bottom surface portion of the portion to be the cavity, and the fired An unfired ceramic green sheet laminated on the substrate may be formed with an opening for forming a cavity before or after the lamination. Here, when forming an opening for forming a cavity in an unfired ceramic green sheet before lamination, the opening for forming the cavity may be formed simultaneously with the processing of the via hole by punching or the like. When forming an opening for forming a cavity in an unfired ceramic green sheet, for example, a ceramic green sheet containing a photosensitive resin is prepared, and a desired opening is formed in the ceramic green sheet by photoetching. An opening for forming a cavity may be formed using a technique or the like. If the fired substrate is positioned on the bottom surface of the cavity and the ceramic multilayer substrate with the cavity is restrained and fired as in claim 6, the bottom surface of the cavity is not warped in a convex shape, and the restraint firing is performed. Therefore, the dimensional accuracy of the cavity can be ensured.

  Further, when manufacturing a ceramic multilayer substrate having a stepped cavity, the number of unfired ceramic green sheets corresponding to the number of layers of the stepped cavity is laminated on the fired substrate as in claim 7. Each time, a constrained green sheet is laminated on the unfired ceramic green sheet and constrained and fired to produce a new fired substrate having a single-step cavity, and then the constrained green sheet remains. After removing the object, the process of laminating and firing the number of unfired ceramic green sheets and restraining green sheets corresponding to the number of layers of the next cavity on the newly fired substrate is repeated. Thus, it is preferable to manufacture a ceramic multilayer substrate having a stepped cavity. In this way, the flatness of each step portion of the stepped cavity can be very good and can be formed with high dimensional accuracy. Also in this case, the cavity forming opening formed in the unfired ceramic green sheet may be formed either before or after lamination.

  The timing for printing the conductor pattern on the unfired ceramic green sheet may be after lamination, but as in claim 8, the unfired ceramic green sheet can be fired simultaneously with the ceramic green sheet. The ceramic green sheets may be laminated after printing the conductor pattern. In this way, when a plurality of unfired ceramic green sheets are laminated on the fired substrate, printing and lamination can be performed efficiently.

  Moreover, you may make it form in the structure where the surface side and back surface side of a ceramic multilayer substrate become asymmetrical like Claim 9. In the manufacturing method of the present invention, even a ceramic multilayer substrate having a complicated structure in which warpage or deformation is likely to occur in the conventional manufacturing method can be manufactured with high dimensional accuracy without warping or deformation.

  Further, as in claim 10, after forming a thick film resistor on the fired substrate, trimming the thick film resistor to adjust the resistance value, and then laminating an unfired ceramic green sheet on the fired substrate You may make it do. In this way, it is possible to manufacture a ceramic multilayer substrate having a built-in high-precision thick film resistor whose resistance value is adjusted by trimming, which cannot be manufactured by the conventional manufacturing method, with high dimensional accuracy.

  The ceramic multilayer substrate manufactured by the manufacturing method according to claims 1 to 10 described above can be used as a multilayer circuit substrate for various uses. For example, as described in claim 11, the ceramic multilayer substrate is manufactured by the manufacturing method according to claims 1 to 12. A modular semiconductor device may be manufactured using a ceramic multilayer substrate as a module substrate. Thus, for example, if a communication module product, a vehicle-mounted module product, etc. are manufactured, a highly reliable module product can be manufactured.

  As is clear from the above description, according to the method for manufacturing a ceramic multilayer substrate of claim 1 of the present invention, an unfired ceramic formed on both surfaces of the fired substrate with a ceramic material different from the fired substrate. Since a green sheet is laminated to produce a laminate, and a constraining green sheet is laminated on this laminate and subjected to restraint firing (pressurization firing or non-pressurization firing). The firing shrinkage, warpage, and deformation of the sheet can be suppressed almost uniformly by the constraining green sheet and the fired substrate from both sides thereof, and a ceramic multilayer substrate free from delamination and warpage can be produced. In addition, the difference in sintering temperature between the fired substrate and the unfired ceramic green sheet and the difference in firing shrinkage properties do not matter, so the sintering temperature and firing of the ceramic material forming each layer of the ceramic multilayer substrate The degree of freedom of material selection with respect to shrinkage characteristics and the like can be greatly expanded, and a ceramic multilayer substrate having a structure that has been difficult to manufacture by conventional manufacturing methods can be manufactured with no dimensional delamination or warpage and with high dimensional accuracy.

  Further, since the fired substrate and the unfired ceramic green sheet are formed of different kinds of ceramic materials, the first aspect of the present invention is a composite ceramic containing various functional materials that are difficult to manufacture by the conventional manufacturing method. Multilayer substrates can be manufactured.

  Further, in claim 2, since both of the unfired ceramic green sheets are temporarily bonded to the fired substrate, both of the fired substrate and the unfired substrate are handled when the laminate is handled in the subsequent steps. There is no risk of misalignment with the fired ceramic green sheet, the laminate is easy to handle, and the adhesion between the ceramic green sheet and the fired substrate can be improved. Can be prevented more reliably.

  Further, in the third aspect, in the step of laminating the constraining green sheet on the unfired ceramic green sheet laminated on the outermost layer of the laminate, both are temporarily fixed. Even in this case, the constraining green sheet can exert a restraining force on the unfired ceramic green sheet, and a ceramic multilayer substrate having a configuration that is difficult to manufacture by the conventional manufacturing method can be manufactured with high dimensional accuracy.

  As described above, the present invention does not cause a problem such as a difference in sintering temperature or a firing shrinkage property between the fired substrate and the unfired ceramic green sheet. Even if the combination of materials of the fired substrate and the unfired ceramic green sheet is changed in various ways, the fired ceramic multilayer substrate can be manufactured with high dimensional accuracy without delamination or warping.

  According to the sixth aspect of the present invention, when the ceramic multilayer substrate with the cavity is manufactured, the fired substrate is placed on the bottom surface portion of the portion forming the cavity and restrained firing is performed, so that the bottom surface portion of the cavity is convex. Therefore, it is possible to manufacture a ceramic multilayer substrate with a cavity having high dimensional accuracy.

  Further, according to the seventh aspect of the invention, when a ceramic multilayer substrate having a stepped cavity is manufactured, each time a number of unfired ceramic green sheets corresponding to the number of layers of the stepped cavity are stacked on the fired substrate. In addition, since the restraining green sheet is laminated on the unfired ceramic green sheet and restrained firing is performed, the shape of each step portion of the stepped cavity can be formed with high dimensional accuracy without deformation.

  According to the eighth aspect of the present invention, since a conductive pattern that can be fired simultaneously with the ceramic green sheet is printed on an unfired ceramic green sheet, the ceramic green sheets are laminated. When the green ceramic green sheets are laminated, printing and lamination can be performed efficiently.

  Further, according to the present invention, even when the front surface side and the back surface side of the ceramic multilayer substrate are asymmetrical as in the ninth aspect, warpage or deformation does not occur, and manufacturing can be performed with high dimensional accuracy.

  Further, in claim 10, a thick film resistor is formed on the fired substrate, and the thick film resistor is trimmed to adjust a resistance value, and then an unfired ceramic green sheet is laminated on the fired substrate. Therefore, a ceramic multilayer substrate having a built-in high-precision thick film resistor whose resistance value is adjusted by trimming, which cannot be manufactured by the conventional manufacturing method, can be manufactured with high dimensional accuracy.

  Moreover, since the semiconductor device which modularized using the ceramic multilayer substrate manufactured with the manufacturing method of Claims 1-10 as a module board | substrate is manufactured, Claim 11 can manufacture a highly reliable module product. .

[Embodiment (1)]
Hereinafter, an embodiment (1) in which the present invention is applied to a method for producing a ceramic multilayer substrate with a single-sided cavity will be described with reference to FIGS.

  As shown in FIGS. 1C and 3, the ceramic multilayer substrate 11 with a single-sided cavity manufactured in the present embodiment (1) has one or a plurality of unfired ceramic substrates on a pre-fired substrate 12. A low-temperature fired ceramic green sheet 13 is laminated, and a restraint fired green sheet 15 is further laminated thereon, followed by restraint firing (pressure firing or pressureless firing) at 800 to 1000 ° C. The ceramic multilayer substrate 11 with a single-sided cavity is manufactured through a process as shown in FIG. 2 with the fired substrate 12 positioned on the bottom surface of the cavity 14.

  First, the baked substrate 12 is prepared. The fired substrate 12 is obtained by firing a ceramic substrate, and may be either a single layer substrate or a multilayer substrate. The ceramic material forming the fired substrate 12 may be any of an insulating ceramic, a dielectric ceramic, a magnetic ceramic, a piezoelectric ceramic, and a ceramic with a resistor. A ceramic material that is sintered at the same temperature as or higher than the sintering temperature of the sheet 13 may be used. Further, when the fired substrate 12 is a multilayer substrate, each layer may be formed of the same type of ceramic, or a structure in which layers formed of different types of ceramics that can be simultaneously fired are mixed.

  In this case, the insulating ceramic is a ceramic used for forming the insulating layer of the substrate, and examples thereof include a low-temperature fired ceramic and a high-temperature sinterable ceramic such as alumina. When the fired substrate 12 is formed of a low-temperature fired ceramic, the same kind of low-temperature fired ceramic as the low-temperature fired ceramic green sheet 13 may be used. It goes without saying that other types of low-temperature fired ceramics that sinter at a high temperature may be used.

Further, a thick film conductor or a RuO ₂ based thick film resistor may be formed on the surface of the fired substrate 12 by simultaneous firing or retrofitting. Further, when a thick film resistor is formed on the surface of the fired substrate 12, the thick film resistor is trimmed before the low-temperature fired ceramic green sheet 13 to be described later is laminated on the fired substrate 12. It is better to adjust.

Furthermore, a low-temperature fired ceramic green sheet 13 is prepared. Examples of the low-temperature fired ceramic material for forming the green sheet 13 include CaO—SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ glass: 50 to 65% by weight (preferably 60% by weight) and alumina: 50 to 50%. A mixture with 35% by weight (preferably 40% by weight) may be used. In addition, a mixture of MgO—SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ glass and alumina, or a mixture of SiO ₂ —B ₂ O ₃ glass and alumina, PbO—SiO ₂ —B ₂ A low-temperature fired ceramic material that can be fired at 800 to 1000 ° C., such as a mixture of O ₃ glass and alumina, or cordierite crystallized glass, may be used.

  The low-temperature fired ceramic green sheet 13 is prepared by blending a low-temperature fired ceramic material having the above composition with a binder (for example, polyvinyl butyral, acrylic resin, etc.), a solvent (for example, toluene, xylene, butanol, etc.) and a plasticizer, and sufficiently stirring. A slurry is prepared by mixing, and this slurry is tape-molded by the doctor blade method or the like.

  After the tape-formed low-temperature fired ceramic green sheet 13 is cut into a predetermined size, a cavity forming opening 14a and a via hole (not shown) are punched into a predetermined position of the green sheet 13 by punching or the like.

  Thereafter, the process proceeds to a printing step, and the via hole of the low-temperature fired ceramic green sheet 13 is filled with a conductive paste of a low melting point metal such as Ag, Ag / Pd, Au, Ag / Pt, or Cu. Further, as shown in FIG. 3, when a plurality of low-temperature fired ceramic green sheets 13 are laminated on the fired substrate 12, Ag, Ag / Pd, Au are added to the low-temperature fired ceramic green sheets 13 laminated on the inner layer. An inner layer conductor pattern (not shown) is screen-printed using a conductor paste of low melting point metal such as Ag / Pt, Cu, etc., and the surface layer conductor pattern ( (Not shown) is screen printed using the same kind of low melting point metal conductor paste. Note that the surface layer conductor pattern may be printed after restraint firing. Further, when manufacturing a ceramic multilayer substrate having a structure without via holes or inner layer conductor patterns, the above printing process may be omitted.

After the printing process, the process proceeds to a laminating process, in which one or a plurality of low-temperature fired ceramic green sheets 13 are laminated on the fired substrate 12, and this laminated body is thermocompression bonded and temporarily fixed (FIG. 1 (a), (See FIG. 3). The conditions for this thermocompression bonding are preferably a pressure of 10 ⁵ to 10 ⁷ Pa and a heating temperature of 60 to 150 ° C. In this laminating step, the thermocompression bonding may be omitted by simply superposing the low-temperature fired ceramic green sheet 13 on the fired substrate 12.

  Then, the constraining green sheets 15 are laminated on both surfaces of the laminate, and are temporarily fixed by thermocompression bonding under the same conditions as described above (see FIG. 1B). Even if the low-temperature fired ceramic green sheet 13 and the fired substrate 12 are not thermocompression bonded in the laminating step, if the constraining green sheet 15 is thermocompression bonded, the low-temperature fired ceramic green sheet 13 and fired in the process. The substrate 12 can be thermocompression bonded. In addition, when baking by pressure, the operation | work which carries out the thermocompression bonding of the restraining green sheet 15 may be abbreviate | omitted.

  As shown in FIGS. 1C and 3, when the low-temperature fired ceramic green sheet 13 is laminated only on one side of the fired substrate 12, the restraining green is only on the side where the low-temperature fired ceramic green sheet 13 is laminated. The sheet 15 may be laminated, and the constrained fired green sheet 15 laminated on the other surface of the fired substrate 12 may be omitted. This is because the fired substrate 12 serves to suppress firing shrinkage of the low-temperature fired ceramic green sheet 13 in the same manner as the restraint fired green sheet 15 during restraint firing.

  In this case, the constrained fired green sheet 15 uses a high temperature sinterable ceramic (for example, alumina, zirconia, magnesia, etc.) that does not sinter at the sintering temperature (800 to 1000 ° C.) of the low temperature fired ceramic. In this powder, a binder (for example, polyvinyl butyral, acrylic, nitrocellulose, etc.), a solvent (for example, toluene, xylene, butanol, etc.) and a plasticizer are blended and mixed thoroughly to prepare a slurry. What is necessary is just to produce the constrained baking green sheet 15 by carrying out tape shaping | molding with a doctor blade method etc. using a slurry.

Thereafter, the laminated body in which the constraining green sheets 15 are laminated is sandwiched between porous setter plates (not shown) formed of alumina, SiC, or the like, and is pressed at a pressure of 10 ⁵ to 10 ⁷ Pa while being fired at a low temperature. Baking is performed at 800 to 1000 ° C., which is the sintering temperature of the ceramic green sheet 13. In this case, the restraining green sheet 15 needs to be thermocompression bonded to the low-temperature fired ceramic green sheet 13 in the step of laminating the restraining green sheet 15.

  At this time, the constraining green sheet 15 (high-temperature sinterable ceramic such as alumina) does not sinter unless heated to about 1300 to 1600 ° C. Therefore, if fired at 800 to 1000 ° C., the constraining green sheet 15 is not yet formed. It remains as sintered. However, in the firing process, organic substances such as a binder in the constraining green sheet 15 are thermally decomposed and scattered to remain as ceramic powder.

  After firing, the residue (ceramic powder) of the constraining green sheet 15 adhering to both surfaces of the fired substrate 11 is removed by blasting, buffing or the like. Thereby, the manufacture of the ceramic multilayer substrate 11 with the single-sided cavity is completed.

  In the present embodiment (1) described above, a laminated body is produced by laminating the unfired low-temperature fired ceramic green sheet 13 on the fired substrate 12, and the restraining green sheet 15 is laminated on the laminated body. (Pressurized firing or non-pressurized firing) Since the firing shrinkage, warpage, and deformation of the unfired low-temperature fired ceramic green sheet 13 during restraint firing, the restraining green sheet 15 and the fired substrate 12 are observed from both sides. Therefore, it is possible to manufacture the ceramic multilayer substrate 11 which is almost uniformly suppressed and free from delamination or warpage.

  Moreover, when manufacturing the ceramic multilayer substrate 11 with the cavity 14 as in the present embodiment (1), if the fired substrate 12 is positioned on the bottom surface of the cavity 14 and restrained and fired, the bottom surface of the cavity 14 Does not warp in a convex shape, and the dimensional accuracy of the cavity 14 can be ensured by restraint firing, and the ceramic multilayer substrate 11 with the cavity 14 having excellent quality can be manufactured. Therefore, even when a semiconductor bare chip is flip-chip mounted on the bottom surface of the cavity 14, the bottom surface of the cavity 14 is not warped, and therefore, the bonding between the bare chip and the conductive pad on the bottom surface of the cavity 14 is performed with high accuracy. And the reliability of flip chip mounting can be improved.

  In addition, the difference in sintering temperature between the fired substrate 12 and the unfired low-temperature fired ceramic green sheet 13, the difference in firing shrinkage characteristics, and the like are not problematic, and therefore, the ceramic material forming each layer of the ceramic multilayer substrate 11 The degree of freedom of material selection with respect to the sintering temperature, firing shrinkage characteristics, etc. can be greatly expanded, and the ceramic multilayer substrate 11 having a configuration that was difficult to manufacture by conventional manufacturing methods has no delamination or warpage, Can be manufactured with good dimensional accuracy.

  In this embodiment (1), the opening 14a for forming a cavity is formed in the low-temperature fired ceramic green sheet 13 before lamination by punching or the like. You may make it form the opening part 14a for cavity formation using a photolithographic technique.

[Embodiment (2)]
In the embodiment (1), the low-temperature fired ceramic green sheets 13 are laminated only on one side of the fired substrate 12. However, as in the embodiment (2) of the present invention shown in FIG. Alternatively, one or a plurality of low-temperature fired ceramic green sheets 13 may be laminated. In this case, after laminating the unfired low-temperature fired ceramic green sheets 13 on both sides of the fired substrate 12, the constrained fired green sheets 15 may be laminated on both sides of the laminate. Other matters may be the same as those in the embodiment (1).

  Even in the case of manufacturing the ceramic multilayer substrate 11 with the double-sided cavities as in this embodiment (2), the bottom portion of the cavities 14 is formed by restraining firing by positioning the fired substrate 12 on the bottom portion of the cavities 14. The ceramic multilayer substrate 11 with a double-sided cavity with good dimensional accuracy can be manufactured without warping in a convex shape.

[Embodiment (3)]
In the embodiments (1) and (2), the cavity 14 is formed in the ceramic multilayer substrate 11, but both cavities 14 are simple cavities without steps. In this case, as shown in FIG. 3, even if a plurality of unfired low-temperature fired ceramic green sheets 13 are simultaneously laminated on the fired substrate 12 and thermocompression bonded, the problem of deformation of the cavity 14 does not occur.

  On the other hand, as shown in FIG. 5D, when the stepped cavity 16 is formed, a plurality of low-temperature fired ceramic green sheets 13 having cavities forming openings 16a having different sizes are laminated at the same time. When thermocompression bonding is performed, a problem occurs that the shape of each step portion of the stepped cavity 16 is deformed by the applied pressure.

  Therefore, in the embodiment (3) of the present invention, when the ceramic multilayer substrate 17 having the stepped cavity 16 is manufactured, first, as shown in FIG. After stacking the number of unfired low-temperature fired ceramic green sheets 13 corresponding to the number of layers for one stage (for example, 1 sheet), a constraining green sheet 15 is stacked on the unfired low-temperature fired ceramic green sheets 13. Then, a new fired substrate 17a having a cavity for one stage is produced by restraint firing. After that, the residual material of the constraining green sheet 15 is removed by blasting or the like, and then, as shown in FIG. 5B, the number of layers corresponding to one step of the next cavity is formed on the new baked substrate 17a. The number of the fired low-temperature fired ceramic green sheets 13 and the restraining green sheets 15 are stacked and fired in a restrained manner. Thereafter, the above-described operation is repeated for the remaining number of steps to manufacture the ceramic multilayer substrate 17 having the stepped cavities 16.

  If the ceramic multilayer substrate 17 having the stepped cavity 16 is manufactured by such a method, the shape of each step portion of the stepped cavity 16 can be formed with high dimensional accuracy without being deformed. Also in this case, the opening 16a for forming a cavity formed in the unfired low-temperature fired ceramic green sheet 13 may be formed at any time before or after lamination.

[Embodiment (4)]
In the embodiment (4) of the present invention shown in FIG. 6, the fired substrate 18 is formed of a functional material other than the insulating ceramic (for example, dielectric ceramic, magnetic ceramic, piezoelectric ceramic, resistor ceramic). There are features. In the example of FIG. 6, a plurality of baked substrates 18 are used, but it goes without saying that a single substrate may be used. When there are a plurality of baked substrates 18, one or a plurality of unfired ceramic green sheets 13 must be sandwiched between the baked substrates 18. Then, the fired substrate 18 and the unfired ceramic green sheet 13 are laminated and thermocompression bonded, and then the restraint fired green sheet 15 is laminated on both surfaces of the laminate and restraint firing to produce a composite ceramic multilayer substrate 19. To do.

  In this manufacturing method, a difference in sintering temperature, a difference in firing shrinkage characteristics, and the like between the fired substrate 18 and the unfired ceramic green sheet 13 do not cause a problem. Therefore, the ceramic material for forming each layer of the composite ceramic multilayer substrate 19 It is possible to greatly expand the degree of freedom of material selection with respect to the sintering temperature, firing shrinkage characteristics, and the like. It can be manufactured with good dimensional accuracy without peeling or warping.

[Embodiment (5)]
The embodiment (5) of the present invention shown in FIG. 7 is an example in the case of producing a composite ceramic multilayer substrate 20 with a cavity 14. In this case, a composite ceramic multilayer substrate manufactured by the same method as in the embodiment (4) is used as the fired substrate 19, and one or a plurality of low-temperature fired ceramic green sheets 13 are provided on both sides of the fired substrate 19, respectively. Are laminated. Each low-temperature fired ceramic green sheet 13 is formed with an opening 14a for forming a cavity before or after lamination. Then, after the low-temperature fired ceramic green sheets 13 are laminated on both sides of the fired substrate 19 and thermocompression bonded, the restraint fired green sheets 15 are laminated on both sides of the laminate and restraint fired to form the composite ceramic with the cavity 14. The multilayer substrate 20 is manufactured.

  The structure of the ceramic multilayer substrate to which the manufacturing method of the present invention can be applied is not limited to the structure of each of the embodiments (1) to (5), but the number of fired substrates, the position of lamination, the number of low-temperature fired ceramic green sheets. Needless to say, the shape of the cavity, the type of ceramic material of each layer of the fired substrate, and the like may be changed as appropriate.

  The ceramic multilayer substrate manufactured by the manufacturing method of each of the embodiments (1) to (5) described above can be used as a multilayer circuit substrate for various applications. For example, the manufacturing method of each of the embodiments (1) to (5) A modular semiconductor device may be manufactured by using the ceramic multilayer substrate manufactured in the above as a module substrate. Thus, for example, if a communication module product, a vehicle-mounted module product, etc. are manufactured, a highly reliable module product can be manufactured.

表１、表２において、焼成済み基板と未焼成セラミックグリーンシートの材料名の（注１）は、ＣａＯ−ＳｉＯ₂ −Ａｌ₂ Ｏ₃ −Ｂ₂ Ｏ₃ 系ガラス：６０重量％とアルミナ：４０重量％との混合物からなる低温焼成セラミックである。また、（注２）は、（注１）のセラミックにより形成した焼成済み基板上に酸化ルテニウム系（ＲｕＯ₂ 系）の厚膜抵抗体を形成し、且つ該厚膜抵抗体をトリミングして抵抗値を調整したものであり、（注３）はＰｂＯ−ＳｉＯ₂ −Ｂ₂ Ｏ₃ 系ガラスとアルミナとの混合物からなる低温焼成セラミックである。また、キャビティの構造の「片面」は、図１（ｃ）に示す片面キャビティ付きのセラミック多層基板を意味し、「両面」は、図４に示す両面キャビティ付きのセラミック多層基板を意味している。 The present inventor manufactured the ceramic multilayer substrate under various conditions using the manufacturing method of each of the above embodiments, and measured the amount of warpage of the bottom surface of the cavity. It is shown in 2.

In Tables 1 and 2, (Note 1) of the material names of the fired substrate and the unfired ceramic green sheet are CaO—SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ glass: 60% by weight and alumina: 40 A low-temperature fired ceramic composed of a mixture with weight percent. In (Note 2), a ruthenium oxide (RuO ₂ ) thick film resistor is formed on a fired substrate made of the ceramic of (Note 1), and the thick film resistor is trimmed to provide resistance. (Note 3) is a low-temperature fired ceramic made of a mixture of PbO—SiO ₂ —B ₂ O ₃ glass and alumina. In addition, “single side” of the cavity structure means the ceramic multilayer substrate with a single-sided cavity shown in FIG. 1C, and “double-sided” means the ceramic multilayer substrate with a double-sided cavity shown in FIG. .

  All sample Nos. Shown in Tables 1 and 2 were used. When the ceramic multilayer substrate subjected to restraint firing was visually inspected for 1 to 28, peeling did not occur between the fired substrate and the sintered layer of the unfired ceramic green sheet, and the sinterability was good.

  Sample No. of a ceramic multilayer substrate with a single-sided cavity manufactured by the manufacturing method of the embodiment (1). In all of Nos. 1 to 16, the cavity bottom portion warpage amount was 5 μm or less, and a ceramic multilayer substrate with a single-sided cavity with good dimensional accuracy was obtained.

  Sample No. 10 is a ceramic multilayer substrate with a single-sided cavity that is restrained and fired without pressure. In this case as well, the restraining green sheet is thermocompression bonded to the low-temperature fired ceramic green sheet in the constraining green sheet laminating process. As a result, a ceramic multilayer substrate with a single-sided cavity having substantially the same quality as in the case of pressure firing was obtained.

  In addition, sample No. 2 of the ceramic multilayer substrate with double-sided cavities manufactured by the manufacturing method of the embodiment (2). In all of Nos. 17 to 19, the warp amount of the bottom surface of the cavity was 5 μm or less, and a ceramic multilayer substrate with a double-sided cavity with good dimensional accuracy was obtained.

Sample No. Nos. 1 to 19 are formed by forming both the fired substrate and the unfired ceramic green sheet laminated thereon with the low-temperature fired ceramic of (Note 1). In Nos. 20 to 26, the fired substrate is formed of a ceramic material different from the low-temperature fired ceramic of Note 1 which is a material for forming the unfired ceramic green sheet, and the fired substrate and the unfired ceramic green sheet are made of different ceramics. It is made of material. For example, sample no. No. 20 is alumina in which the fired substrate is an insulating ceramic; No. 21 is a sintered magnetic ceramic with a sintered substrate, Sample No. In 22, 25, and 26, the fired substrate is formed of a relaxor dielectric ceramic. Sample No. 23, a ruthenium oxide (RuO ₂ ) thick film resistor is formed on the surface of a fired substrate formed of the ceramic of (Note 1), and the thick film resistor is trimmed to obtain an unfired ceramic green sheet. It is formed of a low-temperature fired ceramic made of a mixture of PbO—SiO ₂ —B ₂ O ₃ glass and alumina. Sample No. In 24, the fired substrate is formed of a barium titanate dielectric ceramic.

  Sample No. 27, the fired substrate is formed of the low-temperature fired ceramic of (Note 1), the unfired ceramic green sheet is formed of the low-temperature fired ceramic of (Note 3). In 28, both the fired substrate and the unfired ceramic green sheet laminated thereon are formed of the low-temperature fired ceramic of (Note 3).

  Sample No. in which a fired substrate and an unfired ceramic green sheet are formed of different materials. As for 20 to 27, when the appearance of the ceramic multilayer substrate fired under pressure was inspected, no peeling occurred between the fired substrate and the sintered layer of the green ceramic green sheet, and the sinterability was good. Even when a ceramic multilayer substrate with cavities was manufactured, the amount of warpage of the bottom surface of the cavity was 5 μm or less, and a ceramic multilayer substrate with cavities with good dimensional accuracy was obtained.

  Sample No. 2 in which both the fired substrate and the unfired ceramic green sheet were formed of the low-temperature fired ceramic of (Note 3). For No. 28, the amount of warpage of the bottom surface of the cavity was 5 μm or less, and a ceramic multilayer substrate with a cavity with good dimensional accuracy was obtained.

この表３のサンプルＮｏ．２９、３０は、焼成済み基板と未焼成セラミックグリーンシートとを熱圧着して、拘束焼成グリーンシートを使用しない従来の焼成方法（非拘束焼成）で焼成したものであるが、焼成後のセラミック多層基板を外観検査したところ、焼成済み基板と未焼成セラミックグリーンシートの焼結層との間に剥がれが発生し、焼結不良となった。この試験結果から、拘束焼成グリーンシートを使用しない従来の焼成方法（非拘束焼成）では、焼結不良が発生する可能性が高いことが確認された。 On the other hand, the following Table 3 shows the test results for evaluating the sinterability in the case where the ceramic multilayer substrate with a single-sided cavity is fired by a conventional firing method that does not use a restrained fired green sheet.

Sample No. in Table 3 Nos. 29 and 30 are obtained by thermocompression bonding of a fired substrate and an unfired ceramic green sheet and firing by a conventional firing method that does not use a restrained fired green sheet (unconstrained firing). When the appearance of the substrate was inspected, peeling occurred between the fired substrate and the sintered layer of the unfired ceramic green sheet, resulting in poor sintering. From this test result, it was confirmed that in the conventional firing method (non-constrained firing) that does not use the restrained firing green sheet, there is a high possibility that defective sintering occurs.

It is process drawing explaining the manufacturing method of the ceramic multilayer substrate with the single-sided cavity of Embodiment (1) of this invention. It is a process flowchart explaining the flow of the manufacturing process of Embodiment (1) of this invention. It is a figure explaining the manufacturing method of the ceramic multilayer substrate with a single-sided cavity in case the depth of a cavity is two layers. It is a figure explaining the manufacturing method of the ceramic multilayer substrate with a double-sided cavity of Embodiment (2) of this invention. It is process drawing explaining the manufacturing method of the ceramic multilayer substrate with a stepped cavity of embodiment (3) of this invention. It is a figure explaining the manufacturing method of the composite ceramic multilayer substrate of Embodiment (4) of this invention. It is process drawing explaining the manufacturing method of the composite ceramic multilayer substrate with a double-sided cavity of Embodiment (5) of this invention.

Explanation of symbols

11 Ceramic multilayer substrate 12 Baked substrate 13 Low-temperature fired ceramic green sheet 14 Cavity 14a Opening 15 for cavity 15 Green sheet for restraint firing
16 Stepped cavity 16a... Cavity opening 17 Ceramic multilayer substrate 17a, 18 Firing substrate 19 Composite ceramic multilayer substrate 20 Composite ceramic multilayer substrate

Claims (11)

A ceramic material different from the fired substrate that is sintered on both sides of a pre-fired ceramic substrate (hereinafter referred to as “fired substrate”) at a temperature substantially equal to or lower than the sintering temperature of the fired substrate. Laminating one or a plurality of unfired ceramic green sheets formed by
Laminating a green sheet for restraint that does not sinter at the sintering temperature of the unfired ceramic green sheet on each side of the unfired ceramic green sheet laminated on the outermost layer of the laminate;
A constrained firing step of consolidating the laminate by restraint firing at the sintering temperature of the unfired ceramic green sheet while or without pressurizing the laminate through the restraining green sheet;
And a step of removing a residue of the constraining green sheet after the constraining firing step.   2. The method for producing a ceramic multilayer substrate according to claim 1, wherein in the step of laminating the unfired ceramic green sheet on the fired substrate, both are temporarily fixed.   3. The ceramic multilayer substrate according to claim 1, wherein the constraining green sheet is temporarily fixed in the step of laminating the green ceramic green sheet laminated on the outermost layer of the laminate. Manufacturing method.   4. The method for producing a ceramic multilayer substrate according to claim 1, wherein the green ceramic green sheet is formed of a low-temperature fired ceramic material fired at 1000 [deg.] C. or less.   2. The fired substrate and / or the unfired ceramic green sheet is formed of a ceramic having any of insulating, dielectric, magnetic, piezoelectric, and resistive functions. A method for producing a ceramic multilayer substrate according to any one of claims 1 to 4. A method of manufacturing a ceramic multilayer substrate having a cavity, comprising:
An opening for forming the cavity is formed in the unfired ceramic green sheet, which is laminated on the fired substrate, after the fired substrate is positioned on the bottom surface of the portion where the cavity is formed. A method for producing a ceramic multilayer substrate according to any one of claims 1 to 5, wherein: A method of manufacturing a ceramic multilayer substrate having a stepped cavity, comprising:
Each time the unfired ceramic green sheets corresponding to the number of layers of the stepped cavities are laminated on the fired substrate, the restraining green sheets are laminated on the unfired ceramic green sheets. Then, a new fired substrate having a cavity for one stage is produced by restraint firing, and then the remaining green sheet for restraint is removed, and then the next cavity for one stage is formed on the new fired substrate. A ceramic multilayer substrate having a stepped cavity is manufactured by repeating the operation of laminating and firing a ceramic green sheet and a constraining green sheet corresponding to the number of layers. Item 7. A method for producing a ceramic multilayer substrate according to Item 6.   The ceramic green sheet according to any one of claims 1 to 7, wherein a conductive pattern that can be fired simultaneously with the ceramic green sheet is printed on the green ceramic green sheet, and then the ceramic green sheet is laminated. A method for producing a multilayer substrate.   9. The method for producing a ceramic multilayer substrate according to claim 1, wherein the ceramic multilayer substrate is formed in a structure in which the front surface side and the back surface side are asymmetric.   A thick film resistor is formed on the fired substrate, the thick film resistor is trimmed to adjust a resistance value, and then the green ceramic green sheet is laminated on the fired substrate. Item 10. A method for producing a ceramic multilayer substrate according to any one of Items 1 to 9.   A semiconductor device formed into a module by using the ceramic multilayer substrate produced by the method for producing a ceramic multilayer substrate according to claim 1 as a module substrate.

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