JP5383531B2 - Wiring board manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a wiring board for housing and mounting electronic components such as semiconductor elements and crystal resonators.

  Conventionally, a ceramic board is used as a wiring board for mounting an electronic component and connecting it to a wiring board incorporated in an electronic device, and has a shape having a recess for accommodating the electronic component on the upper surface. is there. The bottom surface of the recess becomes the electronic component mounting area, and the electrodes formed around it (the bottom surface of the recess or the top surface of the substrate around the recess) and each electrode of the electronic component mounted in the electronic component mounting area are soldered or bonded By electrically connecting via a connecting means such as a wire, an electronic device in which the electronic component is housed in the recess and protected from mechanical stress due to contact with the outside or the like is manufactured. A wiring conductor is connected to the electrode, and the wiring conductor is formed to extend to the outer surface of the wiring board, and the wiring conductor exposed on the outer surface and the electrode of the wiring board are joined by soldering or the like. The electronic component is electrically connected to the wiring board. In addition, after electronic components are mounted and electrically connected to the wiring board, a lid made of metal or ceramic is attached to the upper surface of the wiring board with a brazing material or glass and hermetically sealed. In addition to mechanical stress, protection from the atmosphere is also performed.

  Such a ceramic wiring board is manufactured by a green sheet lamination method. For example, a first ceramic green sheet having a wiring conductor pattern and an electrode pattern formed by preparing a ceramic green sheet mainly composed of ceramic powder and an organic binder and printing a conductor paste mainly composed of metal powder. A ceramic green laminate is formed by laminating and press-bonding a second ceramic green sheet having a frame shape by forming a through hole on the top, and then firing the ceramic green laminate by firing the ceramic green laminate. A wiring board is manufactured. In some cases, a plurality of second ceramic green sheets in which through holes having different opening sizes are formed are prepared to form a wiring board having a recess having a step inside (see, for example, Patent Document 1). .

  In the wiring board as described above, in a plan view, one end of the electrode pattern is exposed in the opening of the through hole of the second ceramic green sheet and the other end is overlapped with the second ceramic green sheet. When the second ceramic green sheet is laminated and pressure-bonded on the first ceramic green sheet, there is a step between the portion where the electrode pattern is disposed and the portion where the electrode pattern is not disposed. Between the first ceramic green sheet and the second ceramic green sheet, a gap (open mouth) may be formed on the opening side of the through hole of the second ceramic green sheet. In particular, when the interval between the adjacent electrode patterns becomes narrower as the electronic device is reduced in size and density, the gap may be formed over the entire area between the adjacent electrode patterns. And when immersed in a plating solution to deposit a plating layer on the exposed surface of an electrode or wiring conductor on the surface of a wiring board produced by firing such a laminate, the plating solution enters the gap. When the plating solution is pulled up, the plating solution remains in the gap. And the metal component of the remaining plating solution adheres in a space | gap part, and when adjacent plating electrodes apply | coat, an adjacent electrode may be short-circuited.

Therefore, in order to suppress the generation of voids between the electrodes, a measure of covering the surface of the electrodes with an insulating layer formed of an insulating paste can be considered. Such an insulating layer can be formed by, for example, printing and applying an insulating pattern made of an insulating paste mainly composed of ceramics so as to cover the electrode pattern after the electrode pattern is formed. . In this way, by applying the insulating paste so as to cover the electrode pattern, the insulating paste flows and fills the step when the first ceramic green sheet and the second ceramic green sheet are laminated. Therefore, it can suppress that a space | gap part arises.

JP-A-2005-276910

  However, if the thickness of the insulating pattern as described above is thin, when the second ceramic green sheet is laminated on the first ceramic green sheet and pressed, the opening of the second ceramic green sheet is formed in the insulating pattern. A crack may occur along the line, and the crack may reach the electrode pattern. If such a crack occurs, immersing the wiring board in the plating solution causes the plating solution to enter the crack, and when the wiring substrate is lifted from the plating solution, the plating solution remains in the crack and the metal is removed. Components may adhere and adjacent electrodes may be short-circuited via the metal component.

  Further, when the thickness of the insulating pattern is increased, cracks as described above can be prevented when the second ceramic green sheet is laminated on the first ceramic green sheet and pressed, but the insulating pattern Since the pressure applied to the electrode pattern tends to concentrate at the end, cracks may occur in the electrode pattern along the end of the insulating pattern. When such a crack occurs, the electrode of the wiring board may be disconnected, and it may be impossible to electrically connect the electrode to the wiring conductor in the wiring board.

  The present invention has been devised in view of the above-described problems of the prior art, and an object of the present invention is to provide a method for manufacturing a wiring board capable of suppressing short-circuiting between electrodes and disconnection of electrodes formed in a recess. Is to provide.

  The method of manufacturing a wiring board according to the present invention includes a step of preparing a first ceramic green sheet and a second ceramic green sheet, and forming the second ceramic green sheet into a frame shape by providing a through hole in the center portion. And when the second ceramic green sheet is laminated on the upper surface of the first ceramic green sheet, one end of the second ceramic green sheet is exposed in the opening of the through hole and the other end is the first ceramic green sheet. A step of printing a conductive paste so as to overlap the ceramic green sheet of 2 to form a strip-shaped electrode pattern along the opening of the through-hole, and exposing the one end of the electrode pattern to form a plurality of the electrode patterns and A process of printing a ceramic paste so as to cover between the electrode patterns to form a strip-shaped first insulating pattern along the opening of the through hole. And printing a ceramic paste so that a part of the first insulating green sheet on the center side of the first ceramic green sheet is exposed in a strip shape to cover the first insulating pattern. And forming the upper surface of the first ceramic green sheet so that a part of the second insulating pattern is exposed in a band shape in the opening of the through hole. And a step of producing a laminate by laminating and pressurizing the second ceramic green sheets having a frame shape, and a step of firing the laminate.

According to the method for manufacturing a wiring board of the present invention, the first ceramic green sheet and the second ceramic green sheet are prepared, and the second ceramic green sheet is formed in a frame shape by providing a through hole in the center. On the upper surface of the first ceramic green sheet,
When the second ceramic green sheet is laminated, a conductor paste is printed so that one end of the second ceramic green sheet is exposed in the opening of the through hole and the other end overlaps the second ceramic green sheet in plan view. A step of forming a pattern along the opening of the through hole, and a plurality of electrode patterns and a gap between the electrode patterns by printing a ceramic paste so that one end of the electrode pattern is exposed and a band shape along the opening of the through hole Forming a first insulating pattern, and printing a ceramic paste so as to cover the first insulating pattern by exposing a part of the center side of the first ceramic green sheet of the first insulating pattern in a strip shape A step of forming the second insulating pattern in a strip shape along the first insulating pattern, and a part of the second insulating pattern is exposed in the strip shape in the opening of the through hole. And a step of laminating a frame-shaped second ceramic green sheet on the upper surface of the first ceramic green sheet and pressurizing the laminate, thereby forming an opening in the second ceramic green sheet. In the portion along, the total thickness of the thickness of the first insulating pattern and the thickness of the second insulating pattern can be sufficiently increased. Therefore, it is possible to suppress the generation of cracks that expose the electrode pattern along the opening of the second ceramic green sheet in the insulating pattern. In addition, even when the first ceramic green sheet and the second ceramic green sheet are stacked and pressed, the positions of the end portions of the first insulating pattern and the second insulating pattern are shifted in plan view. Therefore, the pressure is dispersed between the end portion of the first insulating pattern and the end portion of the second insulating pattern located in the opening of the second ceramic green sheet. Generation of cracks in the pattern can be suppressed. Therefore, it is possible to suppress cracks in the insulating pattern and cracks in the electrode pattern that occur when the first ceramic green sheet and the second ceramic green sheet are stacked and pressed. Therefore, it is possible to suppress the occurrence of a short circuit between adjacent electrodes and the disconnection of the electrodes.

(A) is a top view which shows an example of 1 process of embodiment of the manufacturing method of the wiring board of this invention, (b) is sectional drawing which shows the AA cross section of (a). (A) is a top view which shows an example of 1 process of embodiment of the manufacturing method of the wiring board of this invention, (b) is sectional drawing which shows the AA cross section of (a). (A) is a top view which shows an example of 1 process of embodiment of the manufacturing method of the wiring board of this invention, (b) is sectional drawing which shows the AA cross section of (a). (A) is a top view which expands and shows the A section of Fig.3 (a), (b) is sectional drawing which shows the AA line cross section of (a). (A) is a top view which shows the other example of 1 process of embodiment of the manufacturing method of the wiring board of this invention, (b) is sectional drawing which shows the AA cross section of (a). (A) is a top view which shows the other example of 1 process of embodiment of the manufacturing method of the wiring board of this invention, (b) is sectional drawing which shows the AA cross section of (a). (A) is a top view which shows the other example of 1 process of embodiment of the manufacturing method of the wiring board of this invention, (b) is before a 2nd ceramic green sheet is laminated | stacked on (a). It is a top view which shows the example of 1 process of embodiment of the manufacturing method of the wiring board of this invention.

  A method for manufacturing a wiring board according to the present invention will be described in detail with reference to the drawings. 1 to 7, 1 is a first ceramic green sheet, 2 is a second ceramic green sheet, 2a is a through hole, 3 is an electrode pattern, 4 is a first insulating pattern, and 5 is a second insulating pattern. , 6 is a through conductor pattern, 7 is a wiring conductor pattern, 8 is a laminate, and 8a is a recess. 2 to 5 and 7, the portions of the electrode pattern 3 covered with the first insulating pattern 4 and the second insulating pattern 5 and the second ceramic green sheet 2 are shown in a transparent manner with broken lines. ing.

First, a first ceramic green sheet 1 and a second ceramic green sheet 2 are prepared. The first ceramic green sheet 1 and the second ceramic green sheet 2 have a thickness corresponding to the wiring board to be produced.

  The first ceramic green sheet 1 and the second ceramic green sheet 2 are obtained by adding an organic binder and a solvent to a ceramic powder, and adding a predetermined amount of a plasticizer and a dispersing agent as required to obtain a slurry, (Polyethylene terephthalate) is applied onto a resin or paper support by a doctor blade method, lip coater method or die coater method, and then formed into a sheet, and then dried in warm air, vacuum or far infrared It is produced by drying by a drying method such as

Examples of the ceramic powder include aluminum oxide (Al ₂ O ₃ ) powder, aluminum nitride (AlN) powder, glass ceramic powder, and the like, which are appropriately selected according to the characteristics required for the wiring board.

When the ceramic powder is an aluminum oxide powder or aluminum nitride powder, a powder of a component serving as a sintering aid such as silicon oxide (SiO ₂ ) or magnesium oxide (MgO) is added, and manganese oxide (MnO) is used as a colorant. ) Etc. may be added.

The glass ceramic powder is a mixture of glass powder and filler powder in a mass ratio of 10:90 to 99: 1, preferably 40:60 to 80:20. The glass powder of the glass ceramic powder, may be used those conventionally used in glass ceramics, for example, _SiO 2 _-B 2 _{O 3 based, SiO 2 -B 2 O 3 -Al} 2 O 3 system, SiO _{2 -B 2 O 3 -Al 2 O 3} -MO -based (where, M represents Ca, Sr, Mg, Ba, or _{Zn.), SiO 2 -Al 2} O 3 -M1O-M2O -based (where, M1 and M2 Are the same or different and indicate Ca, Sr, Mg, Ba or Zn.), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ₁ O—M ₂ O system (where M 1 and M 2 are the same as above). , SiO ₂ —B ₂ O ₃ —M3 ₂ O system (where M3 represents Li, Na or K), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M3 ₂ O system (where M3 is Same as above In a.), Pb-based, powder glass Bi system and the like are used.

Further, as the filler powder of the glass ceramic powder, what is conventionally used for glass ceramics may be used, for example, a composite oxide of Al ₂ O ₃ , SiO ₂ , ZrO ₂ and an alkaline earth metal oxide, Ceramic powders such as composite oxides of TiO ₂ and alkaline earth metal oxides, composite oxides containing at least one of Al ₂ O ₃ and SiO ₂ (cristobalite, quartz) (for example, spinel, mullite, cordierite) Can be mentioned.

  As the organic binder, those conventionally used for ceramic green sheets may be used. For example, acrylic (acrylic acid, methacrylic acid or a single aggregate or copolymer of esters thereof, specifically, acrylic ester. Copolymer, methacrylic acid ester copolymer, acrylic acid ester-methacrylic acid ester copolymer, etc.), polyvinyl butyral type, polyvinyl alcohol type, acrylic-styrene type, polypropylene carbonate type, cellulose type homopolymer or the like A copolymer is mentioned. In view of decomposability and volatility in the firing step, an acrylic binder is more preferable. Also, the amount of organic binder added varies depending on the ceramic powder, but it may be an amount that is easy to be decomposed and removed during firing and that the ceramic powder is dispersed and the green sheet is easy to handle and process. About 10 to 20% by mass is desirable.

The solvent contained in the slurry is made of organic materials such as hydrocarbons, ethers, esters, ketones, alcohols, etc. so that a slurry having a viscosity suitable for green sheet molding can be obtained by dispersing ceramic powder and organic binder. A solvent and water are mentioned. Among these, solvents having a high evaporation coefficient such as toluene, methyl ethyl ketone, and isopropyl alcohol are preferable because the drying process after slurry application can be completed in a short time. The solvent is added in an amount of 30 to 100% by mass with respect to the ceramic powder so that the viscosity can be applied to the support satisfactorily, specifically about 3 to 100 cps. It is desirable to make it.

  Next, as in the example shown in FIG. 1, the second ceramic green sheet 2 is formed in a frame shape by providing a through hole 2 a in the center. The through hole 2a can be formed by punching or laser processing using a die or punching. The through-hole 2a is formed in a polygonal shape such as a quadrilateral shape, a circular shape or an elliptical shape in plan view.

  Further, as in the example shown in FIG. 2, an electrode pattern 3 made of a conductive paste is formed on the upper surface of the first ceramic green sheet 1. Further, in the example shown in FIG. 2, a wiring conductor pattern 7 serving as a connection pad for connecting to an external circuit board is formed on the lower surface of the first ceramic green sheet 1 as a wiring conductor.

  The electrode pattern 3 is an electrode that is electrically connected to each electrode of an electronic component to be mounted by wire bonding or flip chip mounting, and the electrode is connected to another wiring conductor through a through conductor. The first ceramic green sheet 1 is formed with a through conductor pattern 6 as a through conductor and a wiring conductor pattern 7 as a wiring conductor. The wiring conductor includes a connection pad for connecting to an external circuit board via a bonding material such as solder and an internal wiring layer routed in the board.

  The electrode pattern 3 and the wiring conductor pattern 7 are formed, for example, by forming a through hole for the through conductor pattern 6 in the first ceramic green sheet 1 by punching, punching with a mold, or laser processing, and the through conductor pattern is formed in the through hole. 6 is embedded by screen printing or press filling to form the through conductor pattern 6, and the electrode pattern 3 and the electrode pattern 3 are formed on the upper surface or the lower surface of the first ceramic green sheet 1 where the through conductor pattern 6 is exposed. A conductor paste for the wiring conductor pattern 7 is printed in a predetermined pattern shape by a printing method such as a screen printing method or a gravure printing method, thereby forming a thickness of about 5 to 20 μm.

  The conductive paste is mixed with metal powder with an appropriate organic binder and solvent, and uniformly dispersed by a kneading means such as a ball mill or a planetary mixer. It is produced by adjusting the viscosity to be suitable for.

  This metal powder is a metal powder that is sintered by co-firing with the first ceramic green sheet 1 and the second ceramic green sheet 2 in a subsequent firing step, and is made of tungsten (W), molybdenum (Mo), manganese. Examples thereof include one or more of (Mn), gold (Au), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt) and the like. In the case of two or more kinds, any form such as mixing, alloy, coating, etc. may be used.

As the organic binder for the conductive paste, those conventionally used for the conductive paste can be used. For example, acrylic (acrylic acid, methacrylic acid or their homopolymers or copolymers, specifically, Acrylic ester copolymer, methacrylic ester copolymer, acrylic ester-methacrylic ester copolymer, etc.), polyvinyl butyral, acrylic-styrene, polypropylene carbonate, cellulose, etc. homopolymer or copolymer Coalescence is mentioned. In view of decomposability and volatility in the firing step, acrylic and alkyd organic binders are more preferable. The amount of the organic binder added varies depending on the metal powder, but may be any amount that can be easily decomposed and removed during firing and can disperse the metal powder. It is desirable that the amount of

  The solvent used for the conductor paste is not particularly limited as long as the metal powder and the organic binder can be well dispersed and mixed, and examples thereof include terpineol and butyl carbitol acetate. In view of formability after printing and drying properties, it is preferable to use a low boiling point solvent. Specifically, the solvent is added in an amount of 4 to 15% by mass with respect to the metal powder, and specifically, for the electrode pattern 3 and the wiring conductor pattern 7 so as to have a viscosity enough to form these conductor pastes. The conductive paste is adjusted to be about 500 to 40,000 cps, and the conductive paste for the through conductor pattern 6 is adjusted to be about 15000 to 40,000 cps.

  In order to match the firing shrinkage behavior and shrinkage rate of the first ceramic green sheet 1 or the second ceramic green sheet 2 during firing, or to ensure the bonding strength of the wiring conductor after firing, the conductor paste is made of glass. Or ceramic powder may be added.

  Next, as in the example shown in FIG. 2, the ceramic paste is applied to the upper surface of the first ceramic green sheet 1 so that one end of the electrode pattern 3 is exposed and covers the plurality of electrode patterns 3 and the electrode patterns 3. The band-shaped first insulating pattern 4 is formed along the opening of the through hole 2a by printing, and a part of the central portion of the first ceramic green sheet 1 of the first insulating pattern 4 is exposed in the band shape. Then, a ceramic paste is printed so as to cover the first insulating pattern 4 to form a second insulating pattern 5 along the first insulating pattern 4 in a strip shape.

  The first insulating pattern 4 and the second insulating pattern 5 become insulating layers after firing. The ceramic paste used as the first insulating pattern 4 and the second insulating pattern 5 is an organic binder and solvent suitable for the ceramic powder used to produce the first ceramic green sheet 1 or the second ceramic green sheet 2. And a ceramic paste prepared by adding a necessary amount of a solvent and adjusting the viscosity after homogeneously dispersing and kneading by a kneading means such as a ball mill or a planetary mixer. The first insulating pattern 4 and the second insulating pattern 5 are each formed to a thickness of about 10 to 20 μm.

  Alternatively, the first insulating pattern 4 may be printed and applied, and after the surface of the first insulating pattern 4 is pressed and flattened, the second insulating pattern 5 may be printed and applied. In this way, generation | occurrence | production of a space | gap can be reduced more favorably, and the 2nd insulating pattern 5 can be printed more favorably.

Next, as in the example shown in FIG. 3, the second ceramic green sheet 2 is laminated on the upper surface of the first ceramic green sheet 1 and pressed to produce the laminated body 8 having the recesses 8 a. At this time, the electrode pattern 3, the first insulating pattern 4 and the second insulating pattern 5 are laminated so that the opening edge of the through hole 2 a of the frame-shaped ceramic green sheet 2 overlaps in plan view. The pressurization at this time is performed while heating as necessary. The pressure and heating conditions vary depending on the type and amount of the organic binder used, but are generally a pressure of 2 to 20 MPa and a temperature of 30 to 100 ° C. In order to improve the adhesiveness between the first ceramic green sheet 1 and the second ceramic green sheet 2, an adhesive obtained by mixing a solvent with an organic binder, a plasticizer, or the like may be used. You may arrange | position and pressurize on the ceramic green sheet which laminated | stacked the elastic body which consists of rubber | gum etc. corresponding to the shape of the recessed part 8a of the laminated body 8. FIG.

Further, as in the example shown in FIG. 4, the electrode pattern 3, the first insulating pattern 4, and the second insulating pattern 5 overlap with the opening edge of the through hole 2 a of the second ceramic green sheet 2 in plan view. The lengths that are respectively exposed in the recesses 8a are set to the necessary lengths. For example, the length L1 exposed in the recess 8a on one end side of the electrode pattern 3 is determined when the electrode is electrically connected to each electrode of the electronic component mounted on the wiring board by wire bonding mounting or flip chip mounting. In order to secure an effective area, the length is set to 0.1 mm or more for wire bonding mounting and 0.08 mm or more for flip chip mounting. The first insulating pattern 4 formed in a band shape along the opening of the through hole 2a is formed in a band shape along the length L2 of the width exposed in the through hole 2a and the first insulating pattern 4. The length L3 of the width at which the second insulating pattern 5 is exposed in the through hole 2a needs to be about 0.05 to 0.2 mm, respectively.

  By setting it as the above-mentioned laminated body 8, in the part along opening of the 2nd ceramic green sheet 2, the thickness of the sum total of the thickness of the 1st insulating pattern 4 and the thickness of the 2nd insulating pattern 5 is set. It can be thick enough. Therefore, it is possible to suppress the generation of cracks that expose the electrode pattern 3 along the opening of the second ceramic green sheet 2 in the insulating pattern. Further, even when the first ceramic green sheet 1 and the second ceramic green sheet 2 are laminated and pressed, the end portions of the first insulating pattern 4 and the end portions of the second insulating pattern 5 are seen in a plan view. Since the position is shifted, the pressure is dispersed between the end of the first insulating pattern 4 and the end of the second insulating pattern 5 located in the opening of the second ceramic green sheet 2. Thus, the occurrence of cracks in the electrode pattern 3 can be suppressed by applying pressure. Therefore, it is possible to suppress cracks in the insulating pattern and cracks in the electrode pattern 3 that occur when the first ceramic green sheet 1 and the second ceramic green sheet 2 are stacked and pressed. Therefore, it is possible to suppress the occurrence of a short circuit between adjacent electrodes and the disconnection of the electrodes.

  In the example shown in FIGS. 3 and 4, the laminated body 8 is formed by laminating a total of two ceramic green sheets, each of the first ceramic green sheet 1 and the second ceramic green sheet 2. However, the laminated body 8 may be manufactured by laminating three or more ceramic green sheets by setting one or both of the ceramic green sheets as a plurality. Further, as in the example shown in FIG. 5, the electrode pattern 3, the first insulating pattern 4 and the first insulating pattern 4 are formed on the upper surface of the first ceramic green sheet 1 ′ in which the through hole having a different size from the through hole 2 a is formed. 2 is formed, and the first ceramic green sheet 1 'is laminated on the upper surface of the other first ceramic green sheet 1 and pressed, and then applied to the upper surface of the first ceramic green sheet 1'. By laminating and pressing the second ceramic green sheet 2, a laminated body 8 having a stepped step in the recess 8 a and having the electrode pattern 3 formed on the upper surface of the step may be produced. In the example illustrated in FIG. 5, the stacked body 8 includes two stepped steps, but may include more steps. By providing such a step, the height of the bonding wire at the time of wire bonding can be changed to suppress short circuit between the wires, so that bonding with many bonding wires can be performed in the same direction.

  In the example shown in FIGS. 3 and 5, the electrode pattern 3 is formed only on the upper surface of the first ceramic green sheet 1. However, as in the example shown in FIG. The electrode pattern 3 may be formed also on the upper surface. The electrode pattern 3, the through conductor pattern 6 and the wiring conductor pattern 7 can be formed on the second ceramic green sheet 2 by the same method as that for forming the first ceramic green sheet 1 described above. When another second ceramic green sheet 2 having a through hole 2a having a different size is laminated on the upper surface of the second ceramic green sheet 2 and pressed, the second ceramic green sheet 2 is used. It is preferable to provide the first insulating pattern 4 and the second insulating pattern 5 on the electrode pattern 3 formed on the upper surface in the same manner as described above.

  Such a laminate 8 can be produced by laminating and pressing the first ceramic green sheet 1, the lower second ceramic green sheet 2 and the upper second ceramic green sheet 2 in this order. Alternatively, the first ceramic green sheet 1 and the lower second ceramic green sheet 2 are stacked and pressed, and then the upper second ceramic green sheet 2 is stacked and pressed. It doesn't matter. When an elastic body corresponding to the shape of the concave portion 8a is used for pressurization, the bottom surface of the concave portion 8a and the upper surface of the step can be pressurized, so that the first ceramic green sheet 1 and the second ceramic green sheet 2 of the two sheets are provided. Since the laminate 8 can be manufactured by simultaneously pressing the layers, it is possible to manufacture the laminate 8 with good productivity, dimensional accuracy of the wiring substrate and pattern position accuracy.

When the electrode pattern 3 is formed on the upper surface of the step, the electrode pattern 3 may be formed to extend to the through hole of the first ceramic green sheet 1 or the second ceramic green sheet 2. Thru | or like the example shown in FIG. 7, you may form spaced apart from a through-hole. When the electrode pattern 3 is formed after the through hole is formed, the electrode pattern 3 is formed so as to be separated from the through hole by about 0.1 mm, so that a plurality of conductor pastes are applied to the inner wall surface of the through hole. This is effective in reducing the possibility that the electrode patterns 3 are connected to each other and the electrodes are short-circuited. When the through hole 2a is formed after the electrode pattern 3 is formed, the electrode pattern 3 extending to the through hole 2a is formed by punching the second green sheet 2 so as to overlap the end portion of the electrode pattern 3. Can do.

  A plurality of electrode patterns 3 are formed along the openings of the through holes 2a. In the example shown in FIGS. 3, 5, and 6, twelve electrode patterns 3 are formed side by side along two opposing sides of the opening of the through hole 2 a formed in a square shape. Further, as in the example shown in FIG. 7A, the stacked body 8 may be formed with a plurality of electrode patterns 3 arranged along each of the four sides of the opening of the through hole 2a. Note that, as in the example shown in FIG. 7B, the first insulating pattern 4 and the second insulating pattern 5 are formed in a band shape along each side of the opening of the rectangular through hole 2a in plan view. However, it may be formed so as to have a frame shape as a whole.

  In addition, the first insulating pattern 4 and the second insulating pattern 5 are formed on the entire surface of the upper surface of the first ceramic green sheet 1 overlapping the second ceramic green sheet 2 in plan view. It doesn't matter. In this case, in the region of the upper surface of the first ceramic green sheet 1 that overlaps with the second ceramic green sheet 2, the first insulating pattern 4 and the second insulating pattern are covered only between the electrode pattern 3 and the electrode pattern 3. Since the difference in thickness between the portion where the electrode pattern 3 is formed and the portion where the electrode pattern 3 is not formed is small compared to the case where 5 is formed, the first ceramic green sheet 1 and the second ceramic green sheet 2 are Since the pressure can be applied to the whole of the stacked regions when stacking and pressing are performed, the first ceramic green sheet 1 and the second ceramic green sheet 2 are more closely adhered and stacked. be able to.

And the laminated body 8 produced in this way is baked, and it becomes a wiring board. The firing step consists of removing organic components and sintering the ceramic powder. The organic component is removed by heating the laminate 8 in a temperature range of about 100 to 1000 ° C. to decompose and volatilize the organic component. The sintering temperature varies depending on the ceramic composition, and is performed within a range of about 800 to 1600 ° C. In addition, the firing atmosphere varies depending on the ceramic powder and the conductor material, and is performed in the air, in a reducing atmosphere, or in a non-oxidizing atmosphere, etc. Even if water or the like is included in the atmosphere in order to effectively remove organic components. Good.

On the wiring board (not shown) after firing, a plating layer is applied to the exposed surfaces of the electrodes and wiring conductors by electrolytic plating or electroless plating. Thereby, the adhesion between the wiring conductor and the electronic component, the bonding between the wiring conductor and the wiring conductor of the external circuit board, and the bonding between the electrode and the bonding wire can be strengthened. The plating layer is made of a metal having excellent corrosion resistance, such as nickel and gold. For example, a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  In addition, this invention is not limited to the example of the above-mentioned embodiment, A various change is possible. For example, a plurality of second ceramic green sheets 2 having through-holes 2a formed thereon are stacked and pressed to prepare a plurality of second ceramic green sheets 2 having through-holes 2a. It doesn't matter. Further, when the electrode pattern 3 is formed on the second ceramic green sheet 2, the through-hole 2 a may be formed after the electrode pattern 3 is printed and applied to the second ceramic green sheet 2. In addition, a through hole smaller than the through hole 2 a may be formed in the central portion of the first ceramic green sheet 1. In this case, by mounting a heat sink made of copper (Cu), copper (Cu) -tungsten (W) or the like on the lower surface of the wiring board, electronic components are directly mounted on the heat sink. Therefore, it is possible to obtain a wiring board with excellent heat dissipation, which has improved heat dissipation from electronic components. Moreover, you may form what is called a castellation conductor in which the conductor was formed in the inner surface of the groove | channel formed in the side surface of a wiring board as a wiring conductor. Further, a substrate region that becomes a wiring board may be arranged in the center of one laminated body 8 in the vertical and horizontal directions to produce a so-called multi-cavity wiring board. The first ceramic green sheet 1 may be provided with a through hole, whereby a wiring board provided with the through hole can be formed.

  Example 1 of the wiring board of the present invention will be described. In this embodiment, three stepped steps are provided in each of the four sides of the recess 8a of the laminate 8 of 31 mm × 31 mm × 3.51 mm.

Ceramic powder prepared by mixing 91% by mass of aluminum oxide, 4% by mass of silicon oxide, magnesium oxide and calcium oxide as sintering aids, and 5% by mass of titanium dioxide and chromium oxide as pigments To 100% by mass, add acrylic resin as organic binder to 10% by mass in solid content and 1% by mass of dibutyl phthalate as plasticizer, and mix for 40 hours with ball mill using toluene as a solvent. Prepared. The ceramic slurry was formed into a sheet shape by a doctor blade method to produce a plurality of ceramic green sheets to be the first ceramic green sheet 1 and the second ceramic green sheet 2. These ceramic green sheets were processed as shown below to prepare a first ceramic green sheet 1 and a second ceramic green sheet 2.

  First, the following processing was performed on the first ceramic green sheet 1. First, through holes for through conductor patterns 6 having a diameter of 0.09 to 0.12 mm were formed at predetermined positions of a plurality of ceramic green sheets by a punching die. Then, after filling the through hole for the through conductor pattern 6 with the conductor paste for the through conductor pattern 6, the conductor paste for the wiring conductor pattern 7 was printed and applied to a predetermined surface of the ceramic green sheet by a screen printing method. Thereafter, these ceramic green sheets were laminated and pressed to obtain a first ceramic green sheet 1 having 18 layers and a thickness of 2.038 mm.

Next, the following processing was performed on the second ceramic green sheet 2. A through hole for the through conductor pattern 6 having a diameter of 0.09 to 0.12 mm was formed at a predetermined position of the plurality of ceramic green sheets by a punching die. These ceramic green sheets have through holes 2a with dimensions of 16.651 mm × 16.651 mm and through holes 2a with dimensions of 17.921 mm × 17.921 mm.
Alternatively, any one of 19.699 mm × 19.699 mm through-holes 2a was formed. Then, after filling the through hole for the through conductor pattern 6 with the conductor paste for the through conductor pattern 6, the conductor paste for the wiring conductor pattern 7 was printed and applied to a predetermined surface of the ceramic green sheet by a screen printing method. Thereafter, ceramic green sheets having the same size of the through-hole 2a are stacked and pressed to form a sheet having a thickness of 0.406 mm consisting of two layers having through-holes 2a with dimensions of 16.651 mm × 16.651 mm (lower Also called the second ceramic green sheet 2 on the side) and a thickness of 0.406 mm consisting of two layers with through-holes 2a measuring 17.921 mm x 17.921 mm
Sheet (also referred to as intermediate second ceramic green sheet 2) and a two-layered 0.660 mm thick sheet (a second ceramic green sheet on the upper side) having a through hole 2a having a dimension of 19.699 mm × 19.699 mm 3), three types of ceramic green sheets that are stacked to become the second ceramic green sheet 2 were obtained.

Then, a conductive paste for the electrode pattern 3 is printed and applied on the upper surface of the first ceramic green sheet 1 by screen printing to have a width of about 0.09 to about 0.12 mm and the lower second ceramic green sheet 2. When laminated, the length from the opening edge (L1 + L2 + L3) is about 0.5
A total of 160 electrode patterns 3 each having a thickness H1 of about 18 μm and 40 sides were formed at intervals of about 0.06 to about 0.3 mm so as to be mm.

In addition, a conductive paste for electrode pattern 3 is printed on the upper surface of second ceramic green sheet 2 on the lower side along the opening of through hole 2a having dimensions of 16.651 mm × 16.651 mm by screen printing. The thickness H1 is about 18 μm so that the length (L1 + L2 + L3) from the opening edge when the intermediate second ceramic green sheet 2 is laminated is about 0.53 mm when the width is about 0.09 to about 0.12 mm. A total of 160 electrode patterns 3 each having 40 sides were formed at intervals of 0.06 to 0.3 mm.

In addition, on the upper surface of the intermediate second ceramic green sheet 2, a conductor paste for the electrode pattern 3 is printed by a screen printing method at a position 0.1 mm away from the side of the through hole 2a having dimensions of 17.921 mm × 17.921 mm. When applied, the width is about 0.09 to about 0.12 mm, and when the upper second ceramic green sheet 2 is laminated, the length from the opening edge (L1 + L2 + L3) is about 0.7 m.
m, 144 electrode patterns 3 having a thickness H1 of about 18 μm were formed in a total of 144 with 36 sides on each interval of 0.1 to 0.3 mm.

  Further, a conductor paste for the wiring conductor pattern 7 which is a connection pad for connecting to an external circuit board was printed and applied on the lower surface of the first ceramic green sheet 1 by screen printing.

In addition, the conductor paste for electrode pattern 3 adds 8% by mass in total of dibutyl phthalate, diethylene glycol butyl acetate, cellulose nitrate, isopropyl alcohol, and polyoxyalkylene alkylphenyl ether phosphate to 100% by mass of tungsten powder. And mixed. The conductor paste for the wiring conductor pattern 7 is 3% by mass of aluminum oxide powder, 100% by mass of tungsten powder, dibutyl phthalate, diethylene glycol butyl acetate, cellulose nitrate, isopropyl alcohol, polyoxyalkylene alkyl ether phosphate ester. And a total of 18% by mass of polyoxyalkylene alkyl ether was added and mixed. The conductor paste for penetrating conductor pattern 6 was mixed by adding 20% by mass of aluminum oxide powder and 60% by mass of dibutyl phthalate, α-terpineol and polyethylene glycol stearylamine to 100% by mass of molybdenum powder. It was produced by doing.

Then, on the upper surfaces of the first ceramic green sheet 1, the lower second ceramic green sheet 2, and the intermediate second ceramic green sheet 2, a space between the plurality of electrode patterns 3 and the electrode patterns 3 is obtained by screen printing. A ceramic paste for the first insulating pattern 4 is printed and applied so as to cover the second ceramic green sheet 2 on the lower side, the second ceramic green sheet 2 on the middle, and the second ceramic green sheet on the upper side. A frame-shaped first insulating pattern 4 having a thickness H2 of about 18 μm is formed so that the width (L2 + L3) from each opening edge is about 0.15 mm when 2 is laminated. Furthermore, the ceramic paste for the second insulating pattern 5 is printed and applied so as to cover the first insulating pattern 4 by screen printing, and the second ceramic green sheet 2 on the lower side and the second intermediate ceramic sheet 2 are applied. When the ceramic green sheet 2 and the second ceramic green sheet 2 on the upper side are laminated, a frame-shaped first having a thickness H3 of about 10 μm so that a width (L3) from each opening edge is about 0.1 mm. 2 insulating patterns 5 were formed. In addition, the 1st insulating pattern 4 and the 2nd insulating pattern 5 are the penetration conductor patterns 6 in the area | region in which each penetration conductor pattern 6 is formed so that the connection of the penetration conductor patterns 6 of each sheet | seat may not be prevented. The first insulating pattern 4 and the second insulating pattern 5 having a diameter of about 0.3 mm larger than the size of
A pattern non-formation portion is provided on the surface. The ceramic paste is a total of dibutyl phthalate, diethylene glycol butyl acetate, α-terpineol, cellulose nitrate and isopropyl alcohol with respect to 100% by mass of the same ceramic powder as the first ceramic green sheet 1 and the second ceramic green sheet 2. It was prepared by adding 60% by mass and mixing.

  Further, as Comparative Example 1, a frame-shaped first insulating pattern 4 having a length L2 from the opening edge of the second ceramic green sheet 2 of about 0.15 mm and a thickness H2 of about 18 μm was formed. I prepared something. Further, as Comparative Example 2, a frame-shaped first insulating pattern 4 having a length L2 from the opening edge of the second ceramic green sheet 2 of about 0.15 mm and a thickness H2 of about 28 μm is formed. Prepared. Note that Comparative Example 1 and Comparative Example 2 were manufactured using the same materials and methods as in Example 1 except that the second insulating pattern was not formed and the second insulating pattern was not formed.

Next, the second ceramic green sheet 2 on the lower side is placed on the upper surface of the first ceramic green sheet 1 and laminated by applying pressure (weight: about 2000 kg), and then the second ceramic ceramic in the middle. The green sheet 2 was placed and laminated by applying pressure (loading: about 2000 kg). Furthermore, the laminated body 8 was formed by mounting the second ceramic green sheet 2 on the upper side and pressurizing (loading: about 2000 kg). A total of 364 electrode patterns 3 (in the recess 8a of the laminate 8) (
The bottom surface of the recess: 160, the upper surface of the first step: 160, the upper surface of the second step: 144).

  Next, after removing the organic components by heating the laminate 8 in a nitrogen atmosphere containing water vapor at a temperature of about 1000 ° C. for about 3 hours, the laminated body 8 is heated to about 1500 ° C. in a nitrogen atmosphere containing water vapor. Firing was performed for about 6 hours at a temperature to produce a wiring board. Then, a nickel plating layer having a thickness of about 4 μm and a gold plating layer having a thickness of about 1 μm were sequentially deposited on the exposed surfaces of the electrodes of the wiring board and the wiring conductor by electroless plating.

  In addition, with respect to Example 1, Comparative Example 1, and Comparative Example 2, an appearance inspection of the laminated body 8 was performed, and an electrical continuity between the electrode of the wiring board and the wiring conductor was checked.

As a result, in Example 1, the crack of the electrode pattern 3 of the laminated body 8 and the crack reaching the electrode pattern 3 of the first insulating pattern 4 and the second insulating pattern 5 were not confirmed, and the adjacent electrodes of the wiring board Neither short-circuiting nor disconnection between the electrode and the wiring conductor was confirmed. On the other hand, in the comparative example 1, the crack which reaches the electrode pattern 3 of the 1st insulating pattern 4 of the laminated body 8 was confirmed, and the short circuit of the adjacent electrodes of a wiring board was confirmed. Further, in Comparative Example 2, cracks were confirmed in the electrode pattern 3 of the laminate 8, and conduction failures such as disconnection and resistance abnormality between the electrodes of the wiring board and the wiring conductor were confirmed. As described above, according to the manufacturing method of the present invention, the exposure of the electrode pattern 3 due to the crack generated in the insulating pattern and the crack generated in the electrode pattern 3 can be suppressed, and the short circuit between adjacent electrodes and the disconnection of the electrode can be prevented. It was confirmed that the occurrence was suppressed.

1... First ceramic green sheet 2... 2nd ceramic green sheet 2 a... Through hole 3. 1st insulation pattern 5 ... 2nd insulation pattern 6 ... Penetration conductor pattern 7 ... Wiring conductor pattern 8 ... Laminated body 8a ... ..Recesses

Claims (1)

Preparing a first ceramic green sheet and a second ceramic green sheet;
A step of forming the second ceramic green sheet into a frame shape by providing a through hole in a central portion;
When the second ceramic green sheet is laminated on the upper surface of the first ceramic green sheet, one end is exposed in the opening of the through hole and the other end is the second ceramic green in plan view. Printing a conductive paste so as to overlap the sheet, and forming a strip-shaped electrode pattern along the openings of the through holes; and
A step of printing a ceramic paste so as to cover the plurality of the electrode patterns and the electrode patterns by exposing the one end of the electrode pattern, thereby forming a strip-shaped first insulating pattern along the opening of the through hole When,
A ceramic paste is printed so as to cover a portion of the first insulating pattern on the center side of the first ceramic green sheet of the first insulating pattern so as to cover the first insulating pattern. Forming a strip along the first insulating pattern;
The frame-shaped second ceramic green sheet is laminated on the upper surface of the first ceramic green sheet so that a part of the second insulating pattern is exposed in a band shape in the opening of the through hole. A step of producing a laminate by pressing,
And a step of firing the laminated body.

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