JP5052380B2 - Manufacturing method of ceramic wiring board - Google Patents

Description

  The present invention relates to a method for manufacturing a ceramic wiring board, and more particularly to a method for manufacturing a multi-layer ceramic wiring board by stacking ceramic green sheets.

  In recent years, with the miniaturization of electronic devices, there has been a demand for miniaturization and high performance in electronic components such as multilayer capacitors and multilayer ceramic wiring boards. For example, multilayer capacitors are required to have multilayered thin dielectric layers and conductor layers for miniaturization and high capacity. In addition, in order to reduce the size and increase the density of wiring conductors in multilayer ceramic wiring boards, thinner insulating layers and wiring conductor layers are formed in multiple layers, and the width and spacing of wiring conductor layers must be finer. ing.

  Such electronic parts are made by adding an organic binder, plasticizer, solvent, etc. to ceramic powder to form a slurry, forming a ceramic green sheet (hereinafter also referred to as green sheet) with a doctor blade, etc., and then a conductor containing metal powder. A conductive layer is formed on a green sheet by printing a paste, and then a green sheet on which a plurality of conductive layers are formed is laminated and pressed to obtain a laminated body. Obtained by firing.

  In the printing process of the conductor paste, conventionally, since a pattern is formed by a screen printing method, a fine technique for screen printing has been required. However, the conventional screen printing method has limitations in the width of the wiring conductor layer and the wiring conductor spacing.

  Further, in the laminate, in order to reduce the direct current resistance value which is an important electrical characteristic, it is necessary to form a high aspect conductor pattern with a thick conductor pattern. However, according to the conventional screen printing method, the film thickness decreases as the wiring width decreases, and it becomes difficult to form a conductor pattern.

  In order to solve these problems, a method using an intaglio transfer method has been proposed. According to this manufacturing method, fineness (wiring conductor layer interval 40 μm) and firing thickness 10 μm are obtained by filling the intaglio with a conductor paste to form a conductor pattern, transferring the conductor to the ceramic green sheet, and peeling the intaglio. It can be realized (see, for example, Patent Document 1).

  However, the intaglio transfer method has a problem that a transfer residue to the intaglio occurs in the intaglio peeling process.

  To solve this problem, a method has been proposed in which both the conductive paste and the green sheet described in Patent Document 1 contain a large amount of organic binder.

According to this method, it is said that by including a large amount of organic binder in both the conductor paste and the green sheet, the mutual adhesiveness is improved and transfer defects after intaglio transfer can be eliminated.
JP 2003-31948 A

  However, in the method of including a large amount of the organic binder in both the conductor paste and the green sheet as described in Patent Document 1, there are many voids when the organic binder volatilizes in the firing process of the laminate. End up. As a result, there has been a problem that characteristic deterioration such as a decrease in electric resistance value due to deterioration of the denseness of the conductor layer after firing and a decrease in porcelain strength due to deterioration of the denseness of the ceramic insulating layer occur.

  The present invention has been completed to solve the above-described problems, and provides a method for manufacturing a ceramic substrate having a fine and high-aspect wiring conductor layer and having good ceramic insulating layer characteristics. is there.

The method for producing a ceramic substrate of the present invention includes a first step of filling a conductive paste into an intaglio plate to form a conductor pattern, a second step of applying a ceramic slurry to the intaglio plate on which the conductor pattern is formed, A third step of drying the ceramic slurry to form a ceramic green sheet; a conductor coating step of forming a conductor pattern by applying a conductor paste on the upper surface of the ceramic green sheet formed on the intaglio; A slurry application step of applying a ceramic slurry to the surface of the ceramic green sheet on which a conductor pattern is formed, a green sheet formation step of drying the ceramic slurry to form a ceramic green sheet, a conductor application step, a slurry application step, The green sheet forming process is repeated a predetermined number of times It has a laminating step for forming a click green sheet laminate, and a fourth step of removing the ceramic green sheet laminate from the intaglio.

Preferably, in the above manufacturing method has a fifth step of stacking a plurality of pre-Symbol ceramic green sheet laminate obtained after the fourth step.

  Preferably, in the above manufacturing method, the difference between the solubility parameter of the solvent contained in the ceramic slurry and the solubility parameter of the binder contained in the conductor paste filled in the intaglio is 3 or less.

  Preferably, the manufacturing method includes a step of sticking a support having an adhesive surface to the surface of the ceramic green sheet, and peeling the ceramic green sheet from the intaglio by pulling the support.

  According to the method for manufacturing a ceramic substrate of the present invention, it is possible to reduce a transfer defect of a fine and high aspect conductor pattern and to obtain a ceramic substrate having excellent characteristics of the wiring conductor and the ceramic insulating layer.

  Hereinafter, a method for producing a ceramic substrate according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of a method for producing a ceramic substrate of the present invention. In FIG. 1, 1 is an intaglio, 2a is a conductor paste, 2 is a conductor pattern formed by drying the conductor paste 2a after filling the intaglio 1 and 2c is formed by drying the conductor paste 2a after screen printing. 3a is a ceramic slurry, and 3a is a ceramic green sheet formed by drying the ceramic slurry 3a.

  First, as shown in FIG. 1A, a conductor layer 2 is formed by filling a conductor paste 2a on an intaglio 1 and drying it.

  The intaglio 1 is produced by forming grooves in the shape of the desired conductor pattern 2 by laser processing or the like in an organic resin such as polyolefin, polyester, polyamide, polyimide, or vinyl chloride. Further, when high dimensional accuracy is required, it is also possible to use a stainless steel plate, a ceramic plate, or the like that is less deformed by a solvent or heat.

On the surface of the intaglio 1, the conductor pattern 2 and a ceramic green sheet 3 formed later (hereinafter, the ceramic green sheet 3 to which the conductor pattern 2 is transferred are collectively referred to as “ceramic green sheet 3 with a conductor layer”) are peeled off. In consideration of the properties, it is preferable to apply a release agent. In particular, in order to prevent the ceramic green sheet 3 with a conductor layer from being deformed such as stretching when it is peeled off from the intaglio 1, a surface treatment layer is formed by a release agent in the recess of the intaglio 1. More preferred.

  As a kind of mold release agent, silicone type, fluorine type, long chain alkyl group containing type, alkyd resin type, polyolefin resin type, etc. can be roughly classified. In particular, a silicone type is more desirable from the viewpoints of heat resistance, peelability and cost.

  The intaglio 1 is filled with the conductive paste 2a with a rigid squeegee.

  The conductor paste 2a is prepared by adding an organic binder, an organic solvent, and a dispersant as necessary to the metal conductor powder, and mixing and kneading them by a kneading means such as a ball mill, a three-roll mill, or a planetary mixer. The

  Metal conductor powders include tungsten (W), molybdenum (Mo), manganese (Mn), copper (Cu), silver (Ag), gold (Au), platinum (Pt), aluminum (Al), silver-lead ( Ag-Pd) alloy and silver-platinum (Ag-Pt) alloy, among which Cu, Ag, Au, Pt, Al, which are metal powders sintered at the temperature at which the ceramic magnetic body is fired. An Ag—Pd alloy and an Ag—Pt alloy are more preferable.

  As the organic binder of the conductive paste 2a, those conventionally used for the conductive paste can be used. For example, acrylic (acrylic acid, methacrylic acid or their homopolymers or copolymers, specifically acrylic Acid ester copolymer, methacrylate ester copolymer, acrylic ester-methacrylic ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, or cellulose Examples thereof include a polymer or a copolymer.

  The organic solvent of the conductor paste 2a may be any organic solvent that can disperse and mix the conductor powder and the organic binder. For example, terpineol, butyl carbitol acetate, phthalic acid, or the like can be used.

  For example, the conductor paste 2a is formed by adding and kneading 3 to 10 parts by mass of an organic binder and 10 to 30 parts by mass of an organic solvent with respect to 100 parts by mass of the metal conductor powder raw material.

  1A, after filling the intaglio 1 with the conductor paste 2, the conductor paste 2 is dried in a drying furnace at 50 ° C. for about 30 minutes. In this way, the intaglio 1 filled with the conductor pattern 2 is obtained.

  Next, as shown in FIG. 1B, the ceramic slurry 3a is applied on the intaglio 1 filled with the conductor layer 2 by using a die coater method or the like and then dried in a drying furnace at 50 ° C. for about 20 minutes. Thus, the ceramic green sheet 3 with a conductor layer is formed.

The ceramic powder main component contained in the ceramic slurry 3a includes, for example, Al ₂ O ₃ , AlN, glass ceramic powder (a mixture of glass powder and filler powder), etc. If present, examples thereof include composite perovskite ceramic powders such as BaTiO ₃ series and PbTiO ₃ series, which are appropriately selected in accordance with characteristics required for electronic components.

For example, as the glass ceramic powder, as a glass _component, SiO 2 _-B 2 _{O 3 based, SiO 2 -B 2 O 3 -Al} 2 O 3 _{based, SiO 2 -B 2 O 3 -Al} 2 O 3 -MO -based (Wherein M represents Ca, Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ¹ O—M ² O system (where M ¹ and M ² are the same or different and 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 —M ³ ₂ O system (where M ³ represents Li, Na or K), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ³ ₂ O system (where M ³ is the above) And Pb-based glass, Bi-based glass, etc. .

Further, as the filler powder, for example, Al ₂ O ₃ , SiO ₂ , composite oxide of ZrO ₂ and alkaline earth metal oxide, composite oxide of TiO ₂ and alkaline earth metal oxide, Al ₂ O ₃ and A ceramic powder such as a complex oxide (for example, spinel, mullite, cordierite) containing at least one selected from SiO ₂ is added.

  As the organic binder, those conventionally used for ceramic green sheets can be used. For example, acrylic (a homopolymer or copolymer of acrylic acid, methacrylic acid or an ester thereof, specifically an acrylic ester. Copolymer, methacrylic acid ester copolymer, acrylic acid ester-methacrylic acid ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, cellulose and other homopolymers or copolymers A polymer is mentioned. In view of decomposition and volatility in the firing step, an acrylic binder is more preferable.

  As the solvent contained in the ceramic slurry 3a, a solvent that can disperse and mix the ceramic powder and the organic binder is necessary, and examples thereof include organic solvents such as toluene, ketones, and alcohols, and water. It is done.

  Further, in order to improve the adhesion between the conductor pattern 2 and the ceramic green sheet 3, it is necessary that the solvent of the ceramic slurry 3a appropriately dissolves the organic binder of the conductor pattern 2. Accordingly, the organic binder of the ceramic slurry and the conductor pattern 2 can be appropriately bonded. For this purpose, the solubility parameter of the solvent contained in the ceramic slurry and the conductor pattern 2 filled in the intaglio 1 are included. Selection should be made so that the difference from the solubility parameter of the binder is 3 or less.

  Here, the solubility parameter is a numerical value based on the property that organic components having similar properties are easily compatible with each other, and is also called an SP value. Since those having similar solubility parameter values are easily dissolved, they are used as an index indicating the dissolving power of the organic component. As the solubility parameter of the organic component of the present invention, solubility parameter data published by Kodansha “Solvent Handbook” (Shozo Asahara et al., 1976, first edition) was used.

  The slurry for producing the ceramic green sheet 3 is obtained by adding 5 to 15 parts by mass of an organic binder and 15 to 50 parts by mass of an organic solvent with respect to 100 parts by mass of the ceramic composition powder, and mixing them by a mixing means such as a ball mill. It is prepared to have a viscosity of 3 mPa · s to 100 mPa · s.

  The ceramic slurry is applied using a doctor blade method, a lip coater method, a die coater method or the like. In particular, when an extrusion method such as a die coater method, a slot coater method, or a curtain coater method is used, these are non-contact coating methods, so that the conductor pattern 2 is not mixed by a physical force. Since the ceramic green sheet 3 with a conductor layer can be formed, it is more preferable.

  The ceramic slurry 3a applied on the intaglio 1 is dried by using a radiant heat or heat transfer such as a hot air dryer or a far-infrared dryer, which has been conventionally used, and lowering the vapor pressure of the solvent to volatilize it. It may be performed by using a dryer such as a vacuum dryer.

  The ceramic green sheet 3 may be formed with through conductors such as via-hole conductors and through-hole conductors for connecting the conductor layers 2 between the upper and lower layers as necessary. These through conductors are formed by embedding means such as printing or press filling with a conductive paste for through conductors after forming through holes in a ceramic green sheet with a conductor layer by punching with a mold or laser processing.

  When processing the through hole in the ceramic green sheet 3 with a conductor layer, the ceramic green sheet 3 with a conductor layer may be peeled off from the intaglio plate 1. This is more preferable because it can prevent deformation.

  The through-conductor conductor paste is prepared in the same manner as the conductor paste 2a, and is adjusted to about 15 Pa · s to 40 Pa · s depending on the amount of the solvent and the organic binder.

  In order to adjust the sintering behavior of the conductor paste for through conductor, an inorganic component such as glass or ceramic powder may be further added to the metal conductor powder. The amount of the organic binder is preferably in the range of 3 to 15 parts by mass with respect to 100 parts by mass of these inorganic components. If it is 3 parts by mass or more, it becomes easy to adjust to a paste form, and if it is less than 15 parts by mass, the amount of organic components in the paste is moderate, so the sintered conductor becomes porous or shrinks excessively. Thus, it is possible to suppress the formation of a gap between the inside of the through conductor or between the through conductor and the through hole inner wall.

  Next, as shown in FIG. 1C, the ceramic green sheet 3 with a conductor layer is formed by peeling the conductor pattern 2 and the ceramic green sheet 3 from the intaglio 1. In particular, when the ceramic green sheet 3 is thin or weak in strength, the support 4 having a sticky surface, such as a PET film, is adhered to the surface of the ceramic green sheet 3 and the support 4 is pulled to pull the support 4. The ceramic green sheet 3 is preferably peeled from the intaglio 1.

  Next, as shown in FIG.1 (d), the obtained ceramic green sheets 3 with a conductor layer are aligned, stacked, and press-bonded to produce a ceramic green sheet laminate.

  The method of laminating is a method of applying heat and pressure to the stacked ceramic green sheets 3 with a conductor layer and thermocompression bonding, or a method of thermocompression bonding by applying an adhesive made of an organic binder, plasticizer, solvent, etc. between the sheets. Etc. can be adopted.

  In this manufacturing method, a high-aspect conductor layer can be formed, which may cause a step due to the height of the conductor pattern 2 on the ceramic green sheet in the laminating process, resulting in poor adhesion and delamination. is there. In such a case, the step is relaxed by applying a ceramic slurry on the conductive sheet green sheet 3 and drying the ceramic slurry, thereby forming a laminate that does not cause poor adhesion or delamination. be able to.

  A glass-ceramic wiring board is obtained by debinding the laminate at a temperature of 400 to 600 ° C. in the air or in a humidified nitrogen atmosphere, and then firing at a temperature of 800 to 1000 ° C.

Also, as shown in FIG. 1 (e), a conductive paste 2a is applied to the surface of the ceramic green sheet 3 obtained after FIG. 1 (b) by screen printing or the like to form a conductive pattern 2c, which is then dried. later repeated the predetermined number of times the step of drying after applying the ceramic slurry 3 a from thereon, it is also possible to obtain a ceramic wiring substrate.

  Furthermore, a ceramic wiring board can also be obtained by further laminating multilayer ceramic green sheets 3 obtained by the method shown in FIG. 1 (e) or FIG. 1 (d).

  In addition, a soldering electrode is used for a ceramic wiring board in which a mounting layer for mounting a semiconductor chip or a chip component or a conductive layer for an electrode pad for connecting a coil built-in board as an external wiring board is fired on the surface. In order to strengthen the bonding between the semiconductor chip and the chip component by means of, for example, a nickel layer and a gold layer may be sequentially deposited on the surface of the conductor layer by a plating method or the like.

  The ceramic substrate manufactured by the method as described above is finer and thicker than conventional products. Therefore, a fine and low-resistance conductor layer can be formed. It is done.

  Hereinafter, an example is given and the manufacturing method of the wiring board of the present invention is explained in detail.

  First, a film made of polyimide was grooved with an excimer laser with a width of 20 μm, a depth of 10 μm, and a length of 10 mm, and a silicone-based release agent was coated so as to be easily peeled off.

  Next, the intaglio 1 was filled with the conductor paste 2a using a rigid squeegee. Subsequently, the ceramic slurry 3a was applied and dried to form a ceramic green sheet 3 having a thickness of 100 μm on the conductor pattern 2 and then peeled off to evaluate transferability.

  In Example 1 in Table 1, a methacrylic acid ester polymer was used as the organic binder of the conductor paste 2a, and isopropyl alcohol was used as the solvent of the ceramic slurry 3a. As a result, the transferability is good (◯), and it is possible to peel off the conductor pattern 2 on the intaglio 1 without leaving the conductor pattern 2, and the conductor pattern 2 having a line width of 20 μm and a thickness of 10 μm can be formed on the green sheet 3. Met. In this example, the SP value difference (solubility difference) between each other is 0.8.

  In Example 4 in Table 1, isobutyl methacrylate polymer was used as the organic binder of the conductive paste 2a, and isopropyl alcohol was used as the solvent of the ceramic slurry 3a. As a result, the transferability was unstable (Δ) and there was no breakage of the conductor pattern, but the occurrence of the remaining conductor pattern 2 on the intaglio 1 was confirmed to be about 5%. In this example, the SP value difference (solubility difference) between each other is 3.2.

  Moreover, in Example 9 in Table 1, an acrylic acid-methacrylic acid ester copolymer was used as the organic binder of the conductor paste 2a, and ethyl acetate was used as the solvent of the ceramic slurry 3a. As a result, the transferability was good (◯) and the conductor pattern 2 on the intaglio 1 could be peeled off without remaining. In this example, the SP value difference (solubility difference) between each other is 2.9.

  As the wiring conductor paste 2a, 100 parts by mass of Ag powder, 5 parts by mass of an organic binder and 15 parts by mass of terpineol were added and mixed thoroughly with a stirring deaerator, and then kneaded sufficiently with three rolls. Was used.

  As the ceramic slurry 3a, 10 parts by mass of an acrylic resin and a solvent were added to 100 parts by mass of the glass powder and sufficiently kneaded.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention. For example, although Ag powder is used in the above-described embodiment, the same result can be obtained with Cu, Au, Pt, Al, Ag-Pd alloy, or Ag-Pt alloy powder.

  In the description of the above embodiment, the terms “upper, lower, left and right” are merely used to describe the positional relationship in the drawings, and do not mean the positional relationship in actual use.

It is a figure explaining an example of embodiment of the manufacturing method of the ceramic substrate of this invention.

Explanation of symbols

1: Intaglio 2: Conductor pattern 2a: Conductor paste 2c: Conductor pattern formed by screen printing 3: Ceramic green sheet 3a: Ceramic slurry 4: Support

Claims (4)

A first step of filling the intaglio with a conductive paste to form a conductive pattern;
A second step of applying a ceramic slurry to the intaglio in which the conductor pattern is formed;
A third step of drying the applied ceramic slurry to form a ceramic green sheet;
A conductor applying step of forming a conductor pattern by applying a conductor paste on the upper surface of the ceramic green sheet formed on the intaglio;
A slurry application step of applying a ceramic slurry to the surface of the ceramic green sheet on which the conductor pattern is formed;
A green sheet forming step of drying the ceramic slurry to form a ceramic green sheet;
A laminating step in which a conductor coating step, a slurry coating step, and a green sheet forming step are repeated a predetermined number of times to form a ceramic green sheet laminate;
And a fourth step of peeling off the ceramic green sheet laminate from the intaglio. Method for producing a ceramic wiring substrate according to claim 1 Symbol mounting, characterized in that a fifth step of stacking a plurality of pre-Symbol ceramic green sheet laminate obtained after the fourth degree. A solubility parameter of the solvent contained in the ceramic slurry, a ceramic wiring board according to claim 1 or 2, wherein the difference between the solubility parameter of the binder contained in the conductive paste filled in the intaglio is 3 or less Manufacturing method. The ceramic green sheet laminate is peeled off from the intaglio by sticking a support having an adhesive surface to the surface of the ceramic green sheet and pulling the support in the fourth step. A method for producing a ceramic wiring board according to any one of 1 to 3 .

Images