JP5996293B2 - Manufacturing method of ceramic multilayer substrate - Google Patents

Description

  The present invention relates to a method for manufacturing a ceramic multilayer substrate having a structure in which a plurality of conductor layers and a plurality of ceramic insulating layers are laminated to form a multilayer.

  In recent years, semiconductor integrated circuit elements (IC chips) used as computer microprocessor units (MPUs) have become increasingly faster and more functional, with an accompanying increase in the number of terminals and the pitch between terminals. Tend to be narrower. In general, a large number of terminals are densely arranged on the bottom surface of an IC chip, and such a terminal group is connected to a terminal group on the motherboard side in the form of a flip chip. However, it is difficult to connect the IC chip directly on the mother board because there is a large difference in the pitch between the terminals on the IC chip side terminal group and the mother board side terminal group. For this reason, a method is generally employed in which a package is prepared by mounting an IC chip on an IC chip mounting wiring board, and the package is mounted on a motherboard.

  Various insulating materials can be used for the IC chip mounting wiring board constituting this type of package, and a ceramic multilayer board using ceramic is well known as an example. In this ceramic multilayer substrate, a ceramic material mainly composed of alumina, for example, is used for the insulator portion, and a metal (for example, tungsten) that can be fired simultaneously with alumina is used for the conductor portion.

  Hereinafter, a conventional method for producing a ceramic multilayer substrate will be exemplified.

  First, a slurry is prepared by mixing alumina powder, an organic binder, a solvent, a plasticizer and the like. Then, this slurry is formed into a sheet shape by a conventionally well-known method to produce a ceramic green sheet.

  Then, via holes that penetrate the front and back surfaces of the sheet are formed by performing a conventionally known punching (punching) process on the ceramic green sheet. Next, the via hole is filled with a conductor paste mainly composed of tungsten or the like using a conventionally known paste printing apparatus. Further, a conductor paste is applied to the surface of the ceramic green sheet according to a screen printing method. Here, the conductive paste is printed and formed in a predetermined pattern using a mask having a predetermined pattern corresponding to the circuit wiring to be formed. Thereafter, a plurality of ceramic green sheets are laminated, and are pressed and heated using a conventionally known laminating apparatus, whereby these are pressed and integrated to form a laminated body. Furthermore, a firing process is performed in which the laminate is heated to a predetermined temperature at which alumina can be sintered. After this firing, the ceramic green sheets and the conductive paste are sintered to obtain a ceramic multilayer substrate.

In the above manufacturing method, a resin material having a low glass transition temperature (Tg) is used as the organic binder of the ceramic green sheet, and the organic binder is melted by pressing and heating to form a laminate. Also, as a method of laminating ceramic green sheets, a method of forming a laminate by laminating each ceramic green sheet after applying a solvent to the surface of the ceramic green sheet and pasting the surface is also put into practical use. . In this method, ceramic green sheets coated with a solvent at room temperature are laminated and temporarily bonded. Then, after temporarily bonding the laminated body for 15 to 20 minutes and drying the pasted portion, the laminated body is subjected to final pressure bonding. In this crimping ^process, 30kgf / cm 2 ^~50kgf / cm long ^second high pressure in the stacking direction of the ceramic green sheets (90 to 600 seconds) is added that in the green sheets are crimped.

  As the ceramic multilayer substrate, a substrate in which cavities capable of storing electronic components are formed on both the front and back sides of the substrate has been put into practical use (see, for example, Patent Documents 1 and 2). When manufacturing the ceramic multilayer substrate having the cavity, a flat ceramic green sheet and a frame-shaped ceramic green sheet having a through-hole portion serving as a cavity are prepared. In the flat ceramic green sheet, after performing the first laminating step of laminating the frame-shaped ceramic green sheet on the front surface, the second laminating step of laminating the frame-shaped ceramic green sheet on the back surface is performed. ing.

JP 10-335823 A JP 2010-67729 A

  However, as in the case of the above conventional manufacturing method, when a solvent is applied to the surface of the ceramic green sheet and laminated, the green sheet itself is softened. There is a concern to do. Furthermore, the adhesiveness between the ceramic green sheets may vary depending on conditions such as application variation of the solvent and mixing ratio of the solvent. Further, when a ceramic green sheet of high strength material is used, the content of the resin material that contributes to the adhesion between the ceramic green sheets is reduced, and sufficient adhesion cannot be ensured. In such a case, there is a concern that delamination or clearance between insulating layers in the ceramic multilayer substrate may occur.

  In addition, when laminating a frame-shaped ceramic green sheet that forms a frame around the cavity by the above-described conventional manufacturing method, the green sheet is deformed by the pressurizing force at the time of lamination so that the frame collapses inside the cavity. Thus, a ceramic multilayer substrate may be manufactured. In particular, as the width of the frame portion is narrower and the frame portion is higher, the frame portion is more easily deformed, so that a ceramic multilayer substrate with poor dimensional accuracy is manufactured. In order to avoid such deformation of the frame part, a method of pressing each ceramic green sheet in a state where an elastic material such as rubber is fitted inside the through hole part serving as a cavity has been put into practical use at the time of sheet lamination. Yes. In this case, it is necessary to prepare an elastic material corresponding to the size and shape of the cavity, which increases the manufacturing cost. Further, even in a ceramic multilayer substrate in which a cavity having a step is formed, it is necessary to separately laminate frame-shaped ceramic green sheets in a plurality of steps, which causes the same problem as in a ceramic multilayer substrate in which cavities are formed on both sides.

  In the case of manufacturing a ceramic multilayer substrate having a castellation (end surface through-hole conductor) on the side surface, a castellation forming hole is formed in the ceramic green sheet. In this case, a part of the pasted ceramic green sheet will dig out into the castellation forming hole, preventing the conductor from being arranged on the inner wall of the hole, and making it impossible to form a castellation with high connection reliability. Is concerned. Further, when forming a castellation, the strength of the frame portion becomes weak at the formation portion, and the frame portion is easily deformed.

  Furthermore, since a laminated body is formed by pressurizing a plurality of ceramic green sheets with a high pressure, a large stress is applied to each ceramic green sheet, and an internal stress is generated in the laminated body. For this reason, in the firing step, dimensional variations and warpage of the ceramic multilayer substrate occur. Moreover, in the said conventional manufacturing method, the thickness of the conductor pattern interposed between each ceramic green sheet cannot be absorbed with a ceramic green sheet, but the unevenness | corrugation according to the thickness will be formed in the substrate surface. In particular, when the pressure during lamination is reduced in order to reduce the internal stress of the laminate, there is a concern that the thickness of the conductor pattern cannot be sufficiently absorbed by the ceramic green sheet and the flatness of the substrate surface is deteriorated. The

  Further, the conventional manufacturing method has a problem that it takes a long time for temporary bonding and a long pressing time for the main pressure bonding, resulting in poor working efficiency. Furthermore, since the manufacturing equipment is also enlarged, the manufacturing cost of the ceramic multilayer substrate increases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a ceramic multilayer substrate capable of producing a ceramic multilayer substrate with excellent dimensional accuracy by suppressing deformation of a frame portion formed around the cavity. It is in providing the manufacturing method of.

And as a means (means 1) for solving the above-mentioned problem, it has a substrate main surface and a substrate back surface, and has a structure in which a plurality of ceramic insulating layers and a plurality of conductor layers are laminated to form a multilayer structure, A cavity that is a non-penetrating recess provided on both sides of the substrate main surface and the substrate back surface, on which an element can be mounted , and a width of a frame portion formed around the cavity is 300 μm or less; A method for producing a ceramic multilayer substrate having a height of 700 μm or less, and preparing a non-fired ceramic sheet formed into a sheet shape having a front surface and a back surface using a ceramic material to be the ceramic insulating layer, Preparing an adhesive ceramic sheet formed into a sheet shape including at least the ceramic material, an adhesive, and an organic compound that melts by heating A sheet preparing step for forming, a cavity forming step for forming a through-hole portion serving as the cavity in the unfired ceramic sheet, and an unfired conductor portion serving as the conductor layer on at least one of a front surface and a back surface of the unfired ceramic sheet Forming a conductor portion, forming a flat plate-like unfired ceramic sheet with the through-hole portion not formed through the ceramic sheet for bonding, and a through-hole portion serving as a cavity on the substrate main surface side. After laminating the unfired ceramic sheet and the unfired ceramic sheet in which a through-hole portion serving as a cavity on the back side of the substrate is formed , the ceramic sheet for bonding is heated to a temperature equal to or higher than the melting point of the organic compound. Each ceramic sheet is developed using the pressure jig in a state in which the pressure jig is not in contact with the inner surface of the through-hole portion. A laminated body forming step of forming an unfired ceramic laminate in which the unfired ceramic sheets are integrated via the adhesive ceramic sheet by pressing in a laminating direction. There is a manufacturing method.

  According to the invention described in Means 1, in the laminated body forming step, after the unfired ceramic sheet in which the through-hole portion to be a cavity is formed is laminated through the adhesive ceramic sheet, the temperature is equal to or higher than the melting point of the organic compound. Heated. Since the organic compound melted by this heating functions as a solvent for the pressure-sensitive adhesive, the pressure-sensitive adhesive strength is developed in the adhesive ceramic sheet that has not developed pressure-sensitive adhesive strength before heating. As described above, since the ceramic sheet for adhesion has a sufficient adhesive force, the pressure bonding can be performed in a low pressure and in a short time. For this reason, it is not necessary to insert and pressurize the pressure jig on the inner surface side of the through hole as in the prior art, and the pressure jig is not in contact with the inner surface of the through hole in the stacking direction. By applying pressure, an unfired ceramic laminate in which the ceramic sheets are integrated can be formed. Thus, in the manufacturing method of the present invention, since the unfired ceramic laminate is formed at a low pressure, the deformation of the frame portion (frame portion) formed around the cavity can be kept low. Moreover, in the manufacturing method of this invention, since the internal stress in a non-baking ceramic laminated body can be restrained low, the curvature of the ceramic multilayer substrate at the time of baking can be suppressed. Furthermore, in the laminated body forming process, since the bonding ceramic sheet is softened by melting the organic compound, the unevenness of the unfired conductor portion can be reliably absorbed by the bonding ceramic sheet. A sufficient flatness can be ensured. As a result, a ceramic multilayer substrate with good dimensional accuracy can be manufactured.

  In the case of forming cavities on both the substrate main surface and the back surface of the substrate, in the prior art, an unfired ceramic sheet having a through hole portion serving as a cavity on the substrate main surface side and a through hole portion serving as a cavity on the substrate back surface side are used. The unsintered ceramic sheet had been laminated in separate steps. On the other hand, in this invention, it becomes possible to laminate | stack these unfired ceramic sheets simultaneously with a comparatively low pressure by interposing the ceramic sheet for adhesion | attachment. For this reason, a manufacturing process can be simplified and the manufacturing cost of a ceramic multilayer substrate can be held down low.

  Further, as another means (means 2) for solving the problems of the present invention, it has a substrate main surface and a substrate back surface, and a multilayer structure in which a plurality of ceramic insulating layers and a plurality of conductor layers are laminated. And a method for producing a ceramic multilayer substrate comprising a cavity that is provided so as to open at least one of the substrate main surface and the substrate back surface, has a step, and is a non-penetrating recess capable of mounting an element. Preparing an unfired ceramic sheet formed into a sheet shape having a front surface and a back surface using a ceramic material to be the ceramic insulating layer, and at least the ceramic material, an adhesive, and an organic compound that is melted by heating A sheet preparation step of preparing a ceramic sheet for bonding formed into a sheet and including the cavity in the unfired ceramic sheet A cavity forming step for forming a through-hole portion, a conductor portion forming step for forming an unfired conductor portion serving as the conductor layer on at least one of the front and back surfaces of the unfired ceramic sheet, and the bonding ceramic sheet. And laminating the unfired ceramic sheet, and then heating to a temperature equal to or higher than the melting point of the organic compound to cause the adhesive ceramic sheet to exhibit adhesive force, and a pressure jig is not applied to the inner surface of the through hole. Lamination to form an unfired ceramic laminate in which each unfired ceramic sheet is integrated via the adhesive ceramic sheet by pressing each ceramic sheet in the laminating direction using the pressure jig in contact. There is a method for manufacturing a ceramic multilayer substrate including a body forming step.

  According to the invention described in Means 2, in the laminated body forming step, after the unfired ceramic sheet in which the through-hole portion to be a cavity is formed is laminated through the adhesive ceramic sheet, the temperature is equal to or higher than the melting point of the organic compound. Heated. Since the organic compound melted by this heating functions as a solvent for the pressure-sensitive adhesive, the pressure-sensitive adhesive strength is developed in the adhesive ceramic sheet that has not developed pressure-sensitive adhesive strength before heating. As described above, since the ceramic sheet for adhesion has a sufficient adhesive force, the pressure bonding can be performed in a low pressure and in a short time. For this reason, it is not necessary to insert and pressurize the pressure jig on the inner surface side of the through hole as in the prior art, and the pressure jig is not in contact with the inner surface of the through hole in the stacking direction. By applying pressure, an unfired ceramic laminate in which the ceramic sheets are integrated can be formed. Thus, in the manufacturing method of the present invention, since the unfired ceramic laminate is formed at a low pressure, the deformation of the frame portion (frame portion) formed around the cavity can be kept low. Moreover, in the manufacturing method of this invention, since the internal stress in a non-baking ceramic laminated body can be restrained low, the curvature of the ceramic multilayer substrate at the time of baking can be suppressed. Furthermore, in the laminated body forming process, since the bonding ceramic sheet is softened by melting the organic compound, the unevenness of the unfired conductor portion can be reliably absorbed by the bonding ceramic sheet. A sufficient flatness can be ensured. As a result, a ceramic multilayer substrate with good dimensional accuracy can be manufactured.

  Moreover, when forming the cavity which has a level | step difference, in the prior art, the some unfired ceramic sheet | seat which has a through-hole part from which size differs was laminated | stacked by the separate process. On the other hand, in this invention, it becomes possible to laminate | stack these unfired ceramic sheets simultaneously with a comparatively low pressure by interposing the ceramic sheet for adhesion | attachment. For this reason, a manufacturing process can be simplified and the manufacturing cost of a ceramic multilayer substrate can be held down low.

In section 1, the width of the frame part formed around the cavity (frame portion) is not more 300μm or less, the height of the frame portion (depth of the cavity) is Ru der less 700 .mu.m. Thus, even when the frame portion is narrow and high and its strength becomes relatively weak, the pressure at the time of lamination is sufficiently low, so that deformation of the frame portion can be avoided. Therefore, a ceramic multilayer substrate with good dimensional accuracy can be manufactured.

  In the cavity forming step, a through-hole portion serving as a cavity may be formed in the bonding ceramic sheet in addition to the unfired ceramic sheet. In this case, in the laminated body forming step, a frame is formed between the frame-shaped unfired ceramic sheet that forms the through-hole portion and becomes the frame portion around the cavity, and the flat-plate-shaped unfired ceramic sheet in which the through-hole portion is not formed. A green ceramic laminate is formed by interposing an adhesive ceramic sheet. In addition, you may interpose the ceramic sheet for adhesion without a through-hole part between a frame-shaped unfired ceramic sheet and a flat-plate-shaped unfired ceramic sheet. Even in this case, a plurality of unfired ceramic sheets can be laminated at a relatively low pressure, and a ceramic multilayer substrate with good dimensional accuracy can be manufactured.

  In the laminate forming step, a non-fired ceramic laminate may be formed by disposing a frame-like unfired ceramic sheet in which through holes are formed and forming a frame around the cavity on the front and back surfaces of the adhesive ceramic sheet. . In this case, cavities can be easily formed on both the main surface of the substrate and the back surface of the substrate.

  In the laminated body forming step, it is necessary to press each ceramic sheet in the laminating direction in a state where the adhesive ceramic sheet develops an adhesive strength of 50 gF or more in terms of tensile strength. In this case, for example, the pressure may be applied in a state where an adhesive force of 100 gF or more is developed, or the pressure may be applied in a state where an adhesive force of 150 gF or more is developed. Thus, it becomes possible to form a non-fired ceramic laminated body with a lower applied pressure by increasing the adhesive strength of the ceramic sheet for bonding.

  Some structure may be provided on the side surface of the ceramic multilayer substrate, for example, a castellation that is an end face through-hole conductor may be provided. In this case, by performing the castellation forming step before the laminate forming step, a through hole penetrating in the thickness direction of the unfired ceramic sheet and the bonding ceramic sheet is formed and castellation is not formed in the through hole. A conductor portion for firing castellation is formed. In the present invention, it is not necessary to apply a solvent to the surface of the ceramic green sheet to form a paste as in the prior art. Therefore, a part of the ceramic green sheet pasted as in the prior art does not protrude into the through hole for forming the castellation, and the castellation can be reliably formed. In addition, although the strength of the frame portion is weakened by forming the castellation, in the present invention, the pressure at the time of stacking can be reduced, so that the deformation of the frame portion can be avoided.

In the laminate forming step, it is possible to appropriately set the pressure and time during pressurization within a range that does not cause a decrease in productivity. For example, a low pressure of 1 kgf / cm ² or more and 5 kgf / cm ² or less, and 1 Each ceramic sheet may be pressed in the stacking direction under conditions of a short time of not less than seconds and not more than 120 seconds. Thus, the internal stress in the unfired ceramic laminate can be kept low by forming the unfired ceramic laminate in a relatively low pressure and in a short time. Moreover, in the manufacturing method of the present invention, there is no step of leaving for a long time after temporary bonding as in the prior art, and the pressurization time in the laminate forming step is short, so that the ceramic multilayer substrate can be manufactured efficiently. . Furthermore, a large-scale device such as a high-pressure press is not necessary. For this reason, the manufacturing cost of the ceramic multilayer substrate can be kept low.

  The ceramic sheet for adhesion prepared in the sheet preparation step may be, for example, a ceramic material containing a pressure-sensitive adhesive and an organic compound in a weight less than that of the ceramic material. These may be included so that the weight decreases in the order of the organic compound. Furthermore, the pressure sensitive adhesive may be contained in a proportion of 25 parts by weight or more and the organic compound may be contained in a proportion of 3 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the ceramic material. . By including a pressure-sensitive adhesive or an organic compound in the adhesive ceramic sheet at such a ratio, an adhesive force of 50 gF or more can be reliably expressed in terms of tensile strength.

  The ceramic sheet for adhesion prepared in the sheet preparation process is formed on the release material. In the conductor portion forming step, the conductor portion may be formed after the release material is peeled off from the adhesive ceramic sheet, or the conductor portion may be formed with the release material attached to the adhesive ceramic sheet.

  It is preferable that the unfired ceramic sheet is formed including an organic binder made of a resin material, and the adhesive ceramic sheet is formed without including an organic binder. In this case, the adhesive ceramic sheet can contain more pressure-sensitive adhesive, and sufficient adhesive strength can be ensured.

  In the conductor portion forming step, the unfired conductor portions may be formed on at least one of the front and back surfaces of the unfired ceramic sheet by a technique such as screen printing or transfer.

  The organic compound is an organic compound that melts at a temperature of 60 ° C. or higher, and a high-boiling alcohol that is solid at room temperature may be used. Specific examples of the organic compound include high boiling alcohols such as stearyl alcohol, cetyl alcohol, and behenyl alcohol. In addition to high boiling alcohols, organic compounds such as lauric acid and myristic acid can be used.

  As the ceramic insulating layer, a sintered body of high-temperature fired ceramic such as alumina, aluminum nitride, boron nitride, silicon carbide, silicon nitride or the like is preferably used. Alternatively, a sintered body of low-temperature fired ceramic such as glass ceramic obtained by adding an inorganic ceramic filler such as alumina to borosilicate glass or lead borosilicate glass may be used as the ceramic insulating layer. Furthermore, a sintered body of dielectric ceramic such as barium titanate, lead titanate, strontium titanate or the like may be used as the ceramic insulating layer depending on the application.

  Although it does not specifically limit as a conductor layer and a castellation, For example, a metallized conductor may be sufficient. When the metallized conductor and the ceramic insulating layer are formed by the simultaneous firing method, the metal powder in the metallized conductor needs to have a melting point higher than the firing temperature of the ceramic insulating layer. For example, when the ceramic insulating layer is made of a so-called high-temperature fired ceramic (for example, alumina), as the metal powder in the metallized conductor, nickel (Ni), tungsten (W), molybdenum (Mo), manganese (Mn), etc. These mixed systems can be selected. When the ceramic insulating layer is made of a so-called low-temperature fired ceramic (for example, glass ceramic or the like), copper (Cu) or silver (Ag) or a mixed system thereof can be selected as the metal powder in the metallized conductor.

  The ceramic multilayer substrate of the present invention can be used in various packages such as crystal packages, SAW filter packages, MPU packages, C-MOS packages, CCD packages, LED packages, chip size packages (CSP), and ceramic chip size packages (CCSP). Can be used.

Sectional drawing which shows the ceramic multilayer substrate in 1st Embodiment. Sectional drawing which shows the sheet | seat preparation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the sheet | seat sticking process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the through-hole formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the via conductor part formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the castellation formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the conductor part formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the cavity formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the laminated body formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the laminated body formation process in the manufacturing method of the ceramic multilayer substrate of 1st Embodiment. Sectional drawing which shows the ceramic multilayer substrate after the baking process of 1st Embodiment. Explanatory drawing which shows the measuring method of the adhesive force of the ceramic sheet for adhesion | attachment. Sectional drawing which shows the ceramic multilayer substrate in 2nd Embodiment. Sectional drawing which shows the conductor part formation process in the manufacturing method of the ceramic multilayer substrate of 2nd Embodiment. Sectional drawing which shows the cavity formation process in the manufacturing method of the ceramic multilayer substrate of 2nd Embodiment. Sectional drawing which shows the laminated body formation process in the manufacturing method of the ceramic multilayer substrate of 2nd Embodiment. Sectional drawing which shows the ceramic multilayer substrate after the baking process of 2nd Embodiment. Sectional drawing which shows the ceramic multilayer substrate in 3rd Embodiment. Sectional drawing which shows the sheet | seat preparation process in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment. Sectional drawing which shows the through-hole formation process in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment. Sectional drawing which shows the conductor part formation process in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment. Sectional drawing which shows the film preparation process for transfer in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment. Sectional drawing which shows the conductor part transcription | transfer process in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment. Sectional drawing which shows the conductor part formation process in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment. Sectional drawing which shows the laminated body formation process in the manufacturing method of the ceramic multilayer substrate of 3rd Embodiment.

[First Embodiment]
Hereinafter, a first embodiment in which the present invention is embodied in a ceramic multilayer substrate will be described in detail with reference to the drawings.

  As shown in FIG. 1, the ceramic multilayer substrate 11 of the present embodiment is a plate-like member having an upper surface 12 (substrate main surface) and a lower surface 13 (substrate back surface), and is used for mounting an IC chip. It is done. The ceramic multilayer substrate 11 is a multilayer wiring substrate in which a plurality of ceramic insulating layers 14, 15, 16 and conductor layers 18 are alternately stacked. In the present embodiment, each ceramic insulating layer 14, 15, 16 is made of an alumina sintered body. The conductor layer 18 is a metallized conductor layer mainly composed of tungsten, for example. Although the ceramic multilayer substrate 11 of the present embodiment has a three-layer structure, a multilayer structure of four or more layers may be adopted.

  The ceramic multilayer substrate 11 is provided with a cavity 19 (non-penetrating recess) that opens to the upper surface 12 and a cavity 20 (non-penetrating recess) that opens to the lower surface 13. In the ceramic multilayer substrate 11, the ceramic insulating layer 15 located in the intermediate layer is the bottom of each cavity 19, 20. The ceramic insulating layer 14 located on the upper layer of the ceramic insulating layer 15 is a frame portion 21 formed around the cavity 19. Further, the ceramic insulating layer 16 located below the ceramic insulating layer 15 is a frame portion 22 formed around the cavity 20.

  In the present embodiment, the width of the frame portion 21 is about 250 μm, and the height of the frame portion 21 (depth of the cavity 19) is about 650 μm. The width of the frame portion 22 is about 275 μm, and the height of the frame portion 22 (depth of the cavity 20) is about 650 μm.

  A plurality of terminal pads 24 for mounting an IC chip are provided on the upper surface 23 of the ceramic insulating layer 15 serving as the bottom surface of the cavity 19. A plurality of terminal pads 26 for mounting an IC chip are provided on the lower surface 25 of the ceramic insulating layer 15 serving as the bottom surface of the cavity 20. These terminal pads 24 and 26 are also metallized conductor layers mainly composed of tungsten. A conductor layer 18 is formed at the interface between the ceramic insulating layers 14 and 15 and the interface between the ceramic insulating layers 15 and 16.

  In the ceramic multilayer substrate 11, a sealing metallized conductor layer 28 is provided on the upper surface 12 (the upper surface of the ceramic insulating layer 14) of the outer peripheral portion of the cavity 19 so as to surround the cavity 19. On the metallized conductor layer 28, a plating layer and a brazing material layer (not shown) are provided, and a cap (not shown) is attached via the brazing material layer and the like. This cap closes the opening of the cavity 19.

  In the ceramic multilayer substrate 11, a plurality of terminal pads 29 for mounting on another substrate are formed on the lower surface 13 (the lower surface of the ceramic insulating layer 16) of the outer peripheral portion of the cavity 20. These terminal pads 29 are also metallized conductor layers mainly composed of tungsten.

  A concave portion 30 having a circular cross section is formed on the side surface of each ceramic insulating layer 14 to 16 constituting the ceramic multilayer substrate 11, and a castellation 31 (end surface through-hole conductor) is provided on the surface of the concave portion 30. . The castellation 31 electrically connects the terminal pad 29 and the inner conductor layer 18.

  A plurality of via holes 33 are formed in each ceramic insulating layer 14, 15, 16, and a via conductor 34 mainly composed of tungsten is provided in each via hole 33. The via conductor 34 electrically connects each conductor layer 18, 28 and each terminal pad 24, 26, 29 to each other.

  Next, a method for manufacturing the ceramic multilayer substrate 11 will be described with reference to FIGS.

  First, an alumina powder as a ceramic material, an organic binder, a solvent and the like are mixed to prepare a slurry. And this slurry is shape | molded by the conventionally well-known method (For example, a doctor blade method or a calender roll method), and it cut | disconnects to predetermined size. As a result, as shown in FIG. 2, a plurality of ceramic green sheets 43 (unfired ceramic sheets) formed into a sheet shape having a front surface 41 and a back surface 42 are prepared (sheet preparation step). In the present embodiment, the ceramic green sheet 43 is formed with a thickness of about 650 μm.

  In this sheet preparation step, the bonding ceramic sheet 46 is produced. Specifically, alumina powder as a ceramic material, a liquid pressure-sensitive adhesive, a solvent, an organic compound that melts by heating, and the like are mixed to prepare a slurry. At the time of forming the slurry, a ratio of 25 parts by weight or more and 100 parts by weight or less of the pressure-sensitive adhesive with respect to 100 parts by weight of the alumina powder, and a ratio of 3 parts by weight or more and 15 parts by weight or less of the organic compound that melts by heating. Is contained. And this slurry is shape | molded by the conventionally well-known method into a sheet form, and it cuts to predetermined size after drying. As a result, as shown in FIG. 2, an adhesive ceramic sheet 46 formed into a sheet shape having a front surface 44 and a back surface 45 is prepared.

  In the present embodiment, the adhesive ceramic sheet 46 is formed on the upper surface of the film-like release material 47 with a thickness of 10 μm to 50 μm, for example. As an adhesive contained in the ceramic sheet 46 for adhesion, for example, an acrylic solvent type adhesive (AR-2040 manufactured by Big Technos) is used. As the organic compound, for example, cetyl alcohol (high boiling alcohol) having a melting point of about 56 ° C. is used. Specifically, in the sheet preparation step, when the slurry is cast on the release material 47 (carrier film), the slurry itself is dried. At this time, the solvent of the adhesive is lost, and the adhesive performance of the adhesive is lowered. Further, cetyl alcohol itself is dissolved in the solvent in the slurry, but solidifies because it is below the melting point in this drying. At this time, the solidified cetyl alcohol is collected on the sheet surface side. Therefore, the surface of the bonding ceramic sheet 46 is in a state where the cetyl alcohol having no tackiness occupies most of the surface, and the adhesive having poor bonding performance is slightly exposed. As a result, an adhesive ceramic sheet 46 that does not exhibit tackiness is formed at room temperature, and the process flow of the sheet is facilitated.

Then, an adhesive ceramic sheet 46 is disposed on the back surface 42 of the ceramic green sheet 43, and is heated at a low pressure (for example, a pressure of 3 kgf / cm ² or less) through a release material 47 by a heater block (not shown) heated to 60 ° C. Press (sheet pasting process). At this time, cetyl alcohol dissolves and liquefies in the adhesive ceramic sheet 46. The liquefied cetyl alcohol becomes a solvent for the adhesive, and the adhesive performance of the adhesive is restored. Further, the adhesive occupies most of the surface of the ceramic sheet 46 for adhesion, so that tackiness is developed. For this reason, the adhesive ceramic sheet 46 can be pressed against the back surface 42 of the ceramic green sheet 43 by a low-pressure press. Then, it cools to normal temperature and peels the mold release material 47 from the ceramic sheet | seat 46 for adhesion | attachment. As a result, as shown in FIG. 3, the bonding ceramic sheet 46 is attached to the back surface 42 of the ceramic green sheet 43. At this time, since the surface is cooled to room temperature, the surface on which the release material 47 of the ceramic sheet for bonding 46 is present does not exhibit tackiness.

  In the ceramic green sheets 43 to be the upper and lower ceramic insulating layers 14 and 16, the conductor part forming step (via conductor part formation) is performed with the adhesive ceramic sheet 46 attached to the front surface 41 or the back surface 42 (see FIG. 3). Process and a process including a castellation formation process). On the other hand, the ceramic green sheet 43 to be the ceramic insulating layer 15 as the intermediate layer is subjected to the conductor portion forming step without the adhesive ceramic sheet 46 being attached.

  Specifically, as shown in FIG. 4, through holes 48 and 49 penetrating in the thickness direction of each ceramic green sheet 43 are formed at a plurality of locations of each ceramic green sheet 43. Here, in the upper ceramic green sheet 43, through holes 48 and 49 are also formed in the bonding ceramic sheet 46 disposed on the back surface 42, and in the lower ceramic green sheet 43, the bonding disposed on the front surface 41. Through holes 48 and 49 are also formed in the ceramic sheet 46 for use. These through holes 48 and 49 are formed, for example, by laser drilling using a laser. In addition to the laser drilling, the through holes 48 and 49 may be formed by other methods such as punching (punching). In addition, since the adhesiveness of the adhesive ceramic sheet 46 is not expressed, there is no problem that the adhesive ceramic sheet sticks to a jig or the like when the above process is performed.

  In the ceramic green sheet 43, the through hole 48 is a hole part for forming the via conductor 34, and the through hole 49 is a hole part for forming the castellation 31. That is, after the ceramic firing, the through hole 48 becomes the via hole 33 and a part of the through hole 49 becomes the recess 30.

  Then, conductor portions are formed in the through holes 48 and 49, respectively. More specifically, first, via metallization filling is performed by a conventionally known paste printing apparatus, tungsten paste is filled into the through holes 48, and an unfired via conductor portion 50 to be the via conductor 34 is formed (FIG. 5). reference). That is, the unfired via conductor portion 50 is formed so that the through hole 48 is completely filled with tungsten paste. Next, castellation printing is performed, and a tungsten paste is attached to the inner peripheral surface of the through hole 49 to form an unfired castellation conductor portion 51 that becomes castellation (see FIG. 6). Therefore, the inside of the through hole 49 may not be completely filled with the tungsten paste, and the central portion of the unfired castellation conductor 51 is hollow. As described above, caster printing may be performed after via metallization filling, or after via metallization filling after castal printing.

  Then, an unfired conductor portion 53 is formed on each ceramic green sheet 43 by screen printing (see FIG. 7). In this case, in each ceramic green sheet 43, a tungsten paste is printed on the front surface 41 and the back surface 42 to which the bonding ceramic sheet 46 is not attached by using a mask (not shown), so that an unfired conductor portion is obtained. 53 is formed into a pattern. These unsintered conductor portions 53 are portions to be the conductor layers 18 and 28 and the terminal pads 24, 26, and 29 later.

  Thereafter, the green conductor part 53 formed on each ceramic green sheet 43 is dried by heating to a predetermined temperature. By performing the conductor portion forming step in this manner, the unfired via conductor portion 50, the unfired castellation conductor portion 51, and the unfired conductor portion 53 are formed on the ceramic green sheet 43. Here, since the adhesiveness of the bonding ceramic sheet 46 is not expressed, there is no problem that the bonding ceramic sheet 46 sticks to a jig or the like when the above process is performed.

  Then, a conventionally known punching (punching) process is performed on each ceramic green sheet 43 to be the upper and lower ceramic insulating layers 14 and 16. As a result, as shown in FIG. 8, the through-hole portions 55 and 56 that become the cavities 19 and 20 are formed in each ceramic green sheet 43 (cavity forming step). Here, through-hole portions 55 and 56 serving as cavities 19 and 20 are also formed in the bonding ceramic sheet 46 attached to the front surface 41 or the back surface 42 of each ceramic green sheet 43. Further, the ceramic green sheet 43 to be the ceramic insulating layer 15 as the intermediate layer is a flat sheet having no through holes 55 and 56 without being punched.

  Then, a laminated body formation process is performed using each ceramic green sheet 43. In the laminated body forming step, first, the flat ceramic green sheet 43 in which the through holes 55 and 56 are not formed is disposed in the middle. A frame-shaped ceramic green sheet 43 in which a through-hole portion 55 is formed is placed on the surface 41 of the flat-plate-shaped ceramic green sheet 43, and a frame in which a through-hole portion 56 is formed on the back surface 42. -Shaped ceramic green sheets 43 are placed one on top of the other. Here, the frame-shaped ceramic green sheet 43 serving as the upper layer side is disposed on the front surface 41 of the flat-plate-shaped ceramic green sheet 43 with the back surface 42 on which the adhesive ceramic sheet 46 is attached facing downward. . On the other hand, the frame-shaped ceramic green sheet 43 on the lower layer side is disposed on the back surface 42 of the flat-plate-shaped ceramic green sheet 43 with the front surface 41 side to which the bonding ceramic sheet 46 is attached facing upward. As a result, each ceramic green sheet 43 is laminated in a form in which a frame-shaped adhesive ceramic sheet 46 is interposed between the flat ceramic green sheet 43 and the frame-shaped ceramic green sheet 43 (see FIG. 9). .

Then, as shown in FIG. 10, for example, by using a heater block 58, the bonding ceramic sheet 46 interposed between the ceramic green sheets 43 is heated to a temperature higher than the melting point of cetyl alcohol (for example, 70 ° C.). At this time, cetyl alcohol contained in the adhesive ceramic sheet 46 is melted, and an adhesive strength of 50 gF or more is expressed in the adhesive ceramic sheet 46 in terms of tensile strength. Thereafter, the heater block 58 (pressure jig) is not in contact with the through holes 55 and 56 of the ceramic green sheet 43, and the heater block 58 is used to reduce the pressure from 1 kgf / cm ^{2 to} 5 kgf / cm ^2. In addition, the ceramic green sheets 43 are pressed in the stacking direction under conditions of a short time of 1 second to 120 seconds. More specifically, in the present embodiment, each ceramic green sheet 43 is pressed with a pressure of ² kgf / cm ^{2 and} a pressing time of 5 seconds. As a result, an unfired ceramic laminate 59 in which the ceramic green sheets 43 are integrated with each other through the adhesive ceramic sheet 46 is formed.

  Thereafter, a firing step is performed in which the unfired ceramic laminate 59 is heated to a predetermined temperature (for example, a temperature of about 1500 ° C. to 1800 ° C.) at which alumina can be sintered. After this firing step, the ceramic green sheets 43 and the ceramic sheet for bonding 46 are sintered to obtain the ceramic multilayer substrate 100 (see FIG. 11). At this time, the conductor layers 18, 28, the terminal pads 24, 26, 29, the through-hole conductor 31A, and the via conductor 34 are formed by sintering the tungsten paste. At the time of firing the ceramic, the adhesive of the adhesive ceramic sheet 46 is degreased and burned off at the interface between the ceramic green sheets 43. Thereafter, the alumina of the ceramic sheet for bonding 46 is sintered and the alumina of the ceramic green sheet 43 is sintered, so that the ceramic multilayer substrate 100 in which the ceramic insulating layers 14, 15 and 16 are integrated is obtained.

  The ceramic multilayer substrate 100 obtained here is a multi-layer substrate for a large number of products having a structure in which a plurality of product regions are arranged vertically and horizontally along a plane direction. A plurality of ceramic multilayer substrates 11 shown in FIG. 1 are obtained simultaneously by dividing the multi-layer ceramic multilayer substrate 100 by performing a dividing step. Further, in this dividing step, by dividing the ceramic multilayer substrate 11 at a position where the through-hole conductor 31A is located (a position indicated by an alternate long and short dash line in FIG. 11), a castellation 31 (end surface through-hole conductor) exposed on the side surface of the substrate is obtained. It is formed.

  The inventors cut the ceramic multilayer substrate 11 manufactured by the above manufacturing method in the thickness direction, and observed the cross section of the substrate using a scanning electron microscope (SEM). As a result, it was difficult to determine the boundary between the ceramic insulating layers 14, 15, and 16 due to the presence of the adhesive ceramic sheet 46, and it was confirmed that the ceramic was sintered uniformly without cracks. .

  Moreover, the present inventors confirmed the tensile strength (adhesive force) of the ceramic sheet for adhesion 46 in the laminated body formation process using a test apparatus 61 shown in FIG. The results are shown in Table 1.

Specifically, as shown in FIG. 12, a ceramic green sheet 43 in which an adhesive ceramic sheet 46 is bonded to the surface 41 is prepared. And each sheet | seat 43,46 is heated at 70 degreeC, and the adhesiveness ceramic sheet 46 is made to express adhesiveness. Thereafter, the ceramic green sheet 43 is placed on the flat table 62, and a weight 63 (specifically, a 5 g weight) is placed on the upper surface of the bonding ceramic sheet 46. Further, the peripheral portion of the weight 63 is pressed by a cylindrical pressing jig 64 so that the ceramic green sheet 43 does not float up. Thereafter, the weight 63 is pulled through the wire 66 by raising the spring balance 65, and the load when the weight 63 is peeled off from the bonding ceramic sheet 46 is measured as the tensile strength of the bonding ceramic sheet 46. Here, samples 1 to 3 of the adhesive ceramic sheet 46 were formed by including three different types of pressure-sensitive adhesives, and the tensile strength of each of the adhesive ceramic sheets 46 of samples 1 to 3 was confirmed.

  As shown in Table 1, it was confirmed that the adhesive ceramic sheets 46 of Samples 1 to 3 have an adhesive strength of 70 gF or more in terms of tensile strength. In particular, it was confirmed that the adhesive strength of 150 gF or more was developed in the ceramic sheet for adhesion 46 of Sample 1 or Sample 2. The tensile strength was measured in the same manner at room temperature. As a result, in the case of normal temperature, it was confirmed that the adhesive strength of the bonding ceramic sheets 46 of Samples 1 to 3 was 0 gF, and the adhesive strength was not expressed. In the manufacturing method described above, cooling / heating was repeated, but it was confirmed that the occurrence of tackiness in the adhesive ceramic sheet 46 could be restored up to about 5 times.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the case of the present embodiment, the cetyl alcohol in the ceramic sheet for adhesion 46 is melted by heating in the laminate forming step, and the cetyl alcohol functions as a solvent for the adhesive to form the ceramic sheet for adhesion 46. Adhesive strength is developed. Since the adhesive ceramic sheet 46 in the present embodiment contains the pressure-sensitive adhesive in a proportion of 25 parts by weight or more, the adhesive strength of 50 gF or more can be surely expressed in terms of tensile strength. In particular, depending on the adhesive, an adhesive force of 160 gF or more can be expressed. Thus, since the ceramic sheet 46 for adhesion has sufficient adhesive force, the pressure bonding can be performed in a low pressure and in a short time. For this reason, unlike the prior art, there is no need to insert and apply pressure to the inner surfaces of the through holes 55 and 56, and the heater block 58 is not in contact with the inner surfaces of the through holes 55 and 56. By pressing in the lamination direction in the state, an unfired ceramic laminate 59 in which the ceramic green sheets 43 are integrated can be formed. Thus, in this embodiment, since the unfired ceramic laminate 59 is formed at a low pressure, deformation of the frame portions 21 and 22 formed around the cavities 19 and 20 can be suppressed to a low level. Moreover, since the internal stress in the unfired ceramic laminate 59 can be kept low, warping of the ceramic multilayer substrate 11 during firing can be suppressed. Further, in the laminated body forming step, the bonding ceramic sheet 46 is softened by melting the organic compound, so that the unevenness of the unfired conductor portion 53 can be reliably absorbed by the bonding ceramic sheet 46. The flatness of the substrate 11 can be sufficiently ensured. As a result, the ceramic multilayer substrate 11 with good dimensional accuracy can be manufactured.

  (2) When the cavities 19 and 20 are formed on both the upper surface 12 and the lower surface 13 as in the ceramic multilayer substrate 11 of the present embodiment, the frame-shaped ceramic green sheets 43 are arranged on the upper surface side and the lower surface side in the prior art. It was necessary to laminate in separate steps. On the other hand, in the present embodiment, since the bonding ceramic sheet 46 is interposed, it is possible to perform pressure bonding at a low pressure, and therefore, the frame-shaped ceramic green sheets 43 can be laminated simultaneously. For this reason, a manufacturing process can be simplified and the manufacturing cost of the ceramic multilayer substrate 11 can be suppressed low.

(3) In the present embodiment, the green ceramic laminate 59 is formed by pressing each ceramic green sheet 43 in the laminating direction under conditions of a low pressure of ² kgf / cm ² and a short time of 5 seconds. . In this case, unlike the conventional technique, there is no process of leaving for a long time after temporary bonding, and the pressurization time in the laminated body forming process is short, so that the ceramic multilayer substrate 11 can be efficiently manufactured. Moreover, it is not necessary to pressurize each ceramic green sheet 43 in a state in which an elastic material such as rubber is fitted inside the through hole portions 55 and 56 as in the prior art. Furthermore, a large-scale device such as a high-pressure press is not necessary. Therefore, the manufacturing cost of the ceramic multilayer substrate 11 can be kept low.

(4) In this embodiment, it is not necessary to apply a solvent to the surface of the ceramic green sheet 43 to form a paste as in the prior art. Therefore, a part of the pasted ceramic green sheet 43 does not protrude into the through hole 49 for forming the castellation, and the castellation 31 can be reliably formed. In addition, uniform adhesiveness can be secured at the interface of the ceramic green sheet 43 by interposing the adhesive ceramic sheet 46 without causing variations in adhesiveness due to variations in solvent application and solvent mixing ratio. For this reason, delamination and clearance between the ceramic insulating layers 14 to 16 in the ceramic multilayer substrate 11 can be reliably prevented. Moreover, if the castellation 31 is formed in the frame parts 21 and 22, the strength of the formation part will become weak. In the present embodiment, since the pressure at the time of stacking can be sufficiently lowered, it is possible to reliably manufacture the ceramic multilayer substrate 11 having the castellations 31 while suppressing the deformation of the frame portions 21 and 22.
[Second Embodiment]

  Next, a second embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 13, the ceramic multilayer substrate 11 </ b> A of the present embodiment is different from the first embodiment in that the ceramic multilayer substrate 11 </ b> A is provided with a cavity 19 </ b> A (non-penetrating recess) having an opening on the upper surface 12 side. Hereinafter, the configuration of the ceramic multilayer substrate 11A will be described.

  As shown in FIG. 13, the ceramic multilayer substrate 11A is also a multilayer wiring substrate in which a plurality of ceramic insulating layers 14, 15, 16 and conductor layers 18 are alternately laminated, as in the first embodiment. is there. The materials for forming the ceramic insulating layers 14 to 16 and the conductor layer 18 are the same as those in the first embodiment.

  The cavity 19A of the present embodiment has a two-stage structure, and a step 70 is formed on the outer peripheral side of the bottom surface of the cavity 19A. In the ceramic multilayer substrate 11A, the ceramic insulating layer 14 located in the upper layer and the ceramic insulating layer 15 located in the intermediate layer form the frame portions 71 and 72 formed around the cavity 19A. Further, the ceramic insulating layer 16 located in the lower layer is the bottom of the cavity 19A. In the ceramic multilayer substrate 11 </ b> A, the width of the frame portion 72 of the ceramic insulating layer 15 is formed wider than the frame portion 71 of the ceramic insulating layer 14, and the ceramic insulating layer 15 exposed due to the difference in width between the frame portions 71 and 72. As a result, a step 70 is formed.

  A plurality of terminal pads 24 for mounting an electronic component (for example, a crystal resonator) are provided on the step 70 (the upper surface of the ceramic insulating layer 15) of the cavity 19A. In the cavity 19A, the electronic component is connected to each terminal pad 24, so that the electronic component is stored in a state of floating from the bottom surface of the cavity 19A.

  In the ceramic multilayer substrate 11A, a metallized conductive layer 28 for sealing is provided on the upper surface 12 (the upper surface of the ceramic insulating layer 14) of the outer periphery of the cavity 19A so as to surround the cavity 19A. On the metallized conductor layer 28, a plating layer and a brazing material layer (not shown) are provided, and a cap (not shown) is attached via the brazing material layer and the like. This cap closes the opening of the cavity 19A. A plurality of terminal pads 29 for mounting on another substrate are formed on the lower surface 13 of the ceramic multilayer substrate 11 (the lower surface of the ceramic insulating layer 16).

  A concave portion 30 having a circular cross section is formed on the side surface of each ceramic insulating layer 14 to 16, and a castellation 31 (an end face through-hole conductor) is provided on the surface of the concave portion 30. The castellation 31 electrically connects the terminal pad 29 and the inner conductor layer 18.

  A plurality of via holes 33 are formed in each ceramic insulating layer 14, 15, 16, and a via conductor 34 mainly composed of tungsten is provided in each via hole 33. The via conductor 34 electrically connects the conductor layers 18 and 28 and the terminal pads 24 and 29 to each other.

  Next, a method for manufacturing the ceramic multilayer substrate 11A will be described.

  First, as in the first embodiment, the ceramic green sheet 43 and the ceramic sheet for bonding 46 are prepared by a sheet preparation process (see FIG. 2). Next, a sheet attaching process is performed. In the first embodiment, the ceramic sheet for bonding 46 is attached to the ceramic green sheet 43 to be the upper ceramic insulating layer 14 and the ceramic green sheet 43 to be the lower ceramic insulating layer 16. On the other hand, in the present embodiment, the ceramic sheet for bonding 46 is attached to the ceramic green sheet 43 to be the upper ceramic insulating layer 14 and the ceramic green sheet 43 to be the intermediate ceramic insulating layer 15.

  Thereafter, similarly to the first embodiment, the conductor portion forming step is performed to form the unfired via conductor portion 50, the unfired castellation conductor portion 51, and the unfired conductor portion 53 in each ceramic green sheet 43. (See FIG. 14).

  Then, conventionally known punching (punching) processing is performed on the ceramic green sheets 43 to be the upper and intermediate ceramic insulating layers 14 and 15. As a result, as shown in FIG. 15, through holes 55A and 56A to be the cavities 19A are formed in each ceramic green sheet 43 (cavity forming step). Here, through-hole portions 55A and 56A serving as the cavities 19A are also formed in the bonding ceramic sheet 46 attached to the back surface 42 of each ceramic green sheet 43. The size of the upper layer side through hole portion 55A is larger than the size of the intermediate layer side through hole portion 56A. Further, the ceramic green sheet 43 to be the lower ceramic insulating layer 16 is a flat sheet in which the through holes 55A and 56A are not formed without performing punching.

  Then, a laminated body formation process is performed using each ceramic green sheet 43. In the laminated body forming step, a flat plate-shaped ceramic green sheet 43 in which the through-hole portions 55A and 56A are not formed is disposed in the lower layer. Then, frame-shaped ceramic green sheets 43 having different sizes of the through-hole portions 55A and 56A are arranged on the flat-shaped ceramic green sheet 43 so as to overlap each other. Here, the frame-shaped ceramic green sheets 43 are sequentially arranged with the back surface 42 side to which the adhesive ceramic sheet 46 is attached facing downward. As a result, the ceramic green sheets 43 are laminated in such a manner that the frame-shaped adhesive ceramic sheets 46 are interposed between the ceramic green sheets 43.

Then, as shown in FIG. 16, for example, using the heater block 58, the bonding ceramic sheet 46 interposed between the ceramic green sheets 43 is heated to a temperature higher than the melting point of cetyl alcohol (for example, 70 ° C.). At this time, cetyl alcohol contained in the adhesive ceramic sheet 46 is melted, and an adhesive strength of 50 gF or more is expressed in the adhesive ceramic sheet 46 in terms of tensile strength. The ceramic green sheet 43 is not contacted with the through holes 55A and 56A, and each ceramic green is used with the heater block 58 under a low pressure of ² kgf / cm ² and a short time of 5 seconds. The sheet 43 is pressed in the stacking direction. As a result, an unfired ceramic laminate 59A in which the ceramic green sheets 43 are integrated with each other through the bonding ceramic sheet 46 is formed.

  Thereafter, by performing a firing step, each ceramic green sheet 43 is sintered to obtain a ceramic multilayer substrate 100A (see FIG. 17). The obtained ceramic multilayer substrate 100A is a multi-layer substrate for multi-piece production having a structure in which a plurality of product regions are arranged vertically and horizontally along a plane direction. Then, a plurality of ceramic multilayer substrates 11A shown in FIG. 13 are obtained simultaneously by dividing the multi-layer ceramic multilayer substrate 100A by performing a dividing step.

Thus, even when the ceramic multilayer substrate 11A is manufactured, the same effects as those of the first embodiment can be obtained.
[Third Embodiment]

  Next, a third embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the method for manufacturing the ceramic multilayer substrate is different from that in the first embodiment.

  As shown in FIG. 18, in the ceramic multilayer substrate 11B of the present embodiment, the conductor layers 18 and the terminal pads 24 formed on the upper surface 23 side of the ceramic insulating layer 15 as the intermediate layer are buried in the upper surface 23. In addition, each conductor layer 18 and each terminal pad 26 formed on the lower surface 25 side of the ceramic insulating layer 15 are formed so as to be embedded in the lower surface 25.

  Hereinafter, the manufacturing method of the present embodiment will be described in detail.

  First, a sheet preparation process is performed to prepare a ceramic green sheet 43 and an adhesive ceramic sheet 46A (see FIG. 19). The forming material and the manufacturing method of the ceramic green sheet 43 and the bonding ceramic sheet 46A are the same as those of the first embodiment, but the bonding ceramic sheet 46A is the bonding ceramic of the first embodiment. It is formed thicker than the sheet 46. Specifically, the bonding ceramic sheet 46 </ b> A used in the present embodiment is a portion that becomes the ceramic insulating layer 15 of the intermediate layer, and is formed with substantially the same thickness as the ceramic green sheet 43.

  Next, the conductor part formation process with respect to the ceramic sheet 46A for adhesion | attachment is performed. Specifically, through holes 48 and 49 penetrating in the thickness direction of the ceramic sheet 46A are formed at a plurality of locations on the bonding ceramic sheet 46A (see FIG. 20). Then, conductor portions are formed in the through holes 48 and 49, respectively. More specifically, first, via metallization filling is performed by a conventionally known paste printing apparatus, tungsten paste is filled into the through holes 48, and the unfired via conductor portions 50 to be the via conductors 34 are formed. Next, castellation printing is performed, and a tungsten paste is adhered to the inner peripheral surface of the through hole 49 to form an unfired castellation conductor portion 51 that becomes the castellation 31 (see FIG. 21).

  Next, an unfired conductor portion 53 is formed on the bonding ceramic sheet 46A by a transfer method. Here, the unfired conductor portion 53 is formed by printing a tungsten paste on the surface of the transfer film 75 (see FIG. 22). Thereafter, each adhesive ceramic sheet 46A is heated to a temperature equal to or higher than the melting point of cetyl alcohol (for example, 70 ° C.) using a heater block 58 or the like. At this time, cetyl alcohol dissolves and liquefies in the adhesive ceramic sheet 46A. The liquefied cetyl alcohol serves as a solvent for the adhesive, and the adhesive performance of the adhesive is restored. Further, since the adhesive occupies most of the surface of the adhesive ceramic sheet 46A, stickiness is developed. In this state, the unfired conductor portion 53 is transferred by pressing the transfer film 75 against the front surface 44 and the back surface 45 of the adhesive ceramic sheet 46A to embed the unfired conductor portion 53 (see FIG. 23).

  Thereafter, the adhesive ceramic sheet 46A is cooled to a temperature at which the adhesive ceramic sheet 46A does not exhibit tackiness, that is, a temperature not higher than the melting point of the organic compound (for example, 50 ° C.), and the transfer film 75 is peeled off. As a result, the unfired conductor portion 53 is formed on the front surface 44 and the back surface 45 of the bonding ceramic sheet 46A to be the intermediate ceramic insulating layer 15 (see FIG. 24).

  Further, as in the first embodiment, a conductor portion forming step is performed on the ceramic green sheets 43 to be the ceramic insulating layers 14 and 16 on the upper layer side and the lower layer side, and unfired vias are formed on the ceramic green sheets 43. The conductor part 50, the unfired conductor part 51 for castellation, and the unfired conductor part 53 are formed (see FIG. 24). However, in the present embodiment, the conductor portion forming step is performed in a state where the ceramic sheet for bonding 46 is not attached to each ceramic green sheet 43.

  After the formation of the conductor portions 50, 51, and 53, the ceramic green sheets 43 are punched to form through holes 55 and 56 that become the cavities 19 and 20 in the ceramic green sheets 43 (see FIG. Cavity formation process). Note that the adhesive ceramic sheet 46A to be the intermediate ceramic insulating layer 15 is a flat sheet with no through holes 55 and 56 formed without punching.

  Then, a laminated body formation process is performed using each ceramic green sheet 43 and the ceramic sheet 46A for adhesion | attachment. In the laminated body forming step, first, a flat-plate-like adhesive ceramic sheet 46A in which the through holes 55 and 56 are not formed is disposed in the middle. Then, a frame-shaped ceramic green sheet 43 having through-hole portions 55 and 56 is placed on the front surface 44 and the back surface 45 of the flat plate-shaped adhesive ceramic sheet 46A. As a result. The sheets 43 and 46 are laminated in such a manner that an adhesive ceramic sheet 46 </ b> A is interposed between the ceramic green sheets 43.

Then, similarly to the first embodiment, the heater block 58 is used to heat to a temperature equal to or higher than the melting point of cetyl alcohol (for example, 70 ° C.) to cause the adhesive ceramic sheet 46A to exhibit adhesive force. Then, using the heater block 58, the ceramic green sheets 43 are pressed in the stacking direction under conditions of a low pressure of ² kgf / cm ² and a short time of 5 seconds. As a result, the ceramic green sheets 43 are integrated via the adhesive ceramic sheet 46A to form an unfired ceramic laminate 59B (see FIG. 25).

  Thereafter, by performing a firing step, each ceramic green sheet 43 is sintered to obtain a ceramic multilayer substrate. The obtained ceramic multilayer substrate is a multilayer substrate for multi-piece production having a structure in which a plurality of product regions are arranged vertically and horizontally along a plane direction. A plurality of ceramic multilayer substrates 11B shown in FIG. 18 are obtained simultaneously by dividing the multi-layer ceramic multilayer substrate by performing a dividing step.

  Thus, even when the ceramic multilayer substrate 11B is manufactured, the same effect as that of the first embodiment can be obtained. In the present embodiment, the conductor layers 18 and the terminal pads 24 and 26 are embedded in the ceramic insulating layer 15 as an intermediate layer. Adhesiveness with the insulating layer 15 can be sufficiently secured.

  In addition, you may change each embodiment of this invention as follows.

  In the first embodiment, each ceramic green sheet 43 is laminated with the frame-shaped ceramic ceramic sheet 46 interposed between the frame-shaped ceramic green sheet 43 and the plate-shaped ceramic green sheet 43. However, the present invention is not limited to this. Each ceramic green sheet 43 may be laminated by interposing a plate-shaped ceramic ceramic sheet 46 between the frame-shaped ceramic green sheet 43 and the plate-shaped ceramic green sheet 43. In this case, after attaching the flat adhesive ceramic sheet 46 to the front surface 41 and the back surface 42 of the ceramic green sheet 43 to be the ceramic insulating layer 15 of the intermediate layer, the via conductor portion forming step and the castellation forming step are performed. Further, the ceramic green sheets 43 to be the upper and lower ceramic insulating layers 14 and 16 are subjected to a via conductor portion forming process, a castellation forming process, and the like without attaching the adhesive ceramic sheet 46. Even in this case, the unfired ceramic laminate 59 can be formed at a low pressure, and deformation of the frame portions 21 and 22 can be suppressed.

  In the third embodiment, only the ceramic insulating layer 15 as the intermediate layer is formed using the adhesive ceramic sheet 46A, and the other ceramic insulating layers 14 and 15 are formed using the normal ceramic green sheet 43. It was something. On the other hand, the ceramic insulating layers 14 to 16 may be formed using three adhesive ceramic sheets 46A.

  In the ceramic multilayer substrates 11, 11A and 11B of the above embodiments, the castellation 31 (end surface through-hole conductor) is formed. However, a ceramic multilayer substrate in which the castellation 31 is not formed may be used.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the respective embodiments described above are listed below.

  (1) In means 1 or 2, in the laminate forming step, each ceramic sheet is pressed in the laminating direction in a state in which the adhesive ceramic sheet develops an adhesive strength of 150 gF or more in tensile strength. A method for manufacturing a ceramic multilayer substrate.

(2) In means 1 or 2, in the laminate forming step, each ceramic sheet is laminated under a low pressure of 1 kgf / cm ² or more and 5 kgf / cm ² or less and for a short time of 1 second or more and 120 seconds or less. A method for producing a ceramic multilayer substrate, characterized by pressing in a direction.

  (3) In means 1 or 2, the adhesive ceramic sheet prepared in the sheet preparation step contains the pressure-sensitive adhesive in a proportion of 25 parts by weight or more with respect to 100 parts by weight of the ceramic material, and A method for producing a ceramic multilayer substrate comprising the organic compound in a proportion of 3 parts by weight or more and 15 parts by weight or less.

  (4) In means 1 or 2, the unsintered ceramic sheet is formed including an organic binder made of a resin material, and the ceramic sheet for bonding is formed without including the organic binder. A method for producing a multilayer substrate.

  (5) Means 1 or 2 further includes a firing step of sintering the unfired ceramic laminate to form the ceramic insulating layer and the conductor layer after the laminate formation step. A method for producing a ceramic multilayer substrate.

  (6) In the method 1 or 2, the organic compound is an organic compound that melts at a temperature of 60 ° C. or higher.

  (7) The method for producing a ceramic multilayer substrate according to means 1 or 2, wherein the organic compound is a high-boiling alcohol that is solid at room temperature.

  (8) A method for producing a ceramic multilayer substrate, characterized in that, in the means 2, the frame-shaped green ceramic sheets having different through-hole portions are stacked with the frame-shaped adhesive ceramic sheet interposed therebetween.

DESCRIPTION OF SYMBOLS 11, 11A, 11B ... Ceramic multilayer substrate 12 ... Upper surface as substrate main surface 13 ... Lower surface as substrate back surface 14, 15, 16 ... Ceramic insulation layer 18 ... Conductive layer 19, 19A, 20 ... Cavity 21, 22, 71, 72 ... Frame portions 24, 26, 28, 29 ... Terminal pads as conductor layers 31 ... Castellation 41 ... Front surface of unfired ceramic sheet 42 ... Back surface of unfired ceramic sheet 43 ... Ceramic green sheet 44 as unfired ceramic sheet 44 ... front surface of the ceramic sheet for adhesion 45 ... back surface of the ceramic sheet for adhesion 46, 46A ... ceramic sheet for adhesion 49 ... through hole 51 ... conductor part for unsintered castellation 53 ... unsintered conductor part 55, 55A, 56, 56A ... Through-hole portion 58 ... Heater block 59, 59 as a pressure jig , 59B ... green ceramic laminate 70 ... step

Claims (4)

It has a substrate main surface and a substrate back surface, and has a multilayered structure in which a plurality of ceramic insulating layers and a plurality of conductor layers are laminated, and is provided so as to open on both surfaces of the substrate main surface and the substrate back surface, A method for producing a ceramic multilayer substrate comprising a cavity which is a non-penetrating recess capable of mounting an element , wherein a width of a frame formed around the cavity is 300 μm or less, and a height of the frame is 700 μm or less. There,
An unfired ceramic sheet formed into a sheet shape having a front surface and a back surface using a ceramic material to be the ceramic insulating layer is prepared, and includes at least the ceramic material, an adhesive, and an organic compound that is melted by heating. A sheet preparation step of preparing a ceramic sheet for bonding formed into a sheet shape with,
A cavity forming step for forming a through-hole portion serving as the cavity in the green ceramic sheet;
A conductor part forming step of forming an unfired conductor part to be the conductor layer on at least one of the front and back surfaces of the unfired ceramic sheet;
The non- fired ceramic sheet having a flat plate shape in which the through hole portion is not formed via the ceramic sheet for bonding, the unfired ceramic sheet in which the through hole portion serving as a cavity on the substrate main surface side is formed, and the substrate And laminating a non-fired ceramic sheet having a through-hole portion to be a cavity on the back surface side, and then heating to a temperature equal to or higher than the melting point of the organic compound to cause the adhesive ceramic sheet to exhibit adhesive force and Each ceramic sheet is pressed through the bonding ceramic sheet by pressing each ceramic sheet in the stacking direction using the pressure jig in a state where the pressure jig is not in contact with the inner surface of the hole. And a laminated body forming step of forming an unfired ceramic laminated body integrated with a ceramic multilayer substrate. In the cavity forming step, in addition to the unfired ceramic sheet, the adhesive ceramic sheet is formed with a through-hole portion that becomes the cavity,
In the laminated body forming step, a frame is formed between the unfired ceramic sheet having a frame shape in which the through hole portion is formed and serving as the frame portion, and the unfired ceramic sheet having a flat plate shape in which the through hole portion is not formed. The method for producing a ceramic multilayer substrate according to claim 1 , wherein the green ceramic laminate is formed by interposing an adhesive ceramic sheet. The said laminated body formation process pressurizes each ceramic sheet to the lamination direction in the state which expressed the adhesive force of 50 gF or more by the tensile strength of the said adhesive ceramic sheet, The Claim 1 or 2 characterized by the above-mentioned. A method for producing a ceramic multilayer substrate. The ceramic multilayer substrate is a substrate provided with a castellation which is an end surface through-hole conductor on its side surface,
Before the laminated body forming step, a through hole that penetrates in the thickness direction of the unfired ceramic sheet and the bonding ceramic sheet is formed, and an unfired castellation conductor portion that becomes the castellation is formed in the through hole. method for producing a ceramic multilayer substrate according to any one of claims 1 to 3, characterized in that the castellations forming step of forming.

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