JP4000050B2 - Manufacturing method of ceramic laminate - Google Patents

Description

【００８２】
表１の結果から明らかなように、本発明である導体パターンを形成後にセラミックパターンを形成して逐次積層を行うＡ工程を用い、かつ、導体パターンの外縁とセラミックパターンの内縁との間隔Ｄ１よりも、導体パターンの外角縁とセラミックパターンの内角縁との間隔Ｄ２を同等もしくは狭くした試料Ｎｏ．１〜５では、焼成後および熱衝撃試験後においてデラミネーションが見られた試料もあったが、母体成形体を切断した後の成形体での密着不良が０％であった。また、静電容量のばらつきも１．６％以下と良好であった。
【００８３】
また、その間隔の比をＤ２／Ｄ１≦０．８とした試料Ｎｏ．１〜４では、焼成後のデラミネーション発生率が１％となり、さらに、０．１≦Ｄ２／Ｄ１≦０．５とした試料Ｎｏ．２〜３では、熱衝撃試験後のデラミネーション発生率が０％であった。
【００８４】
さらに、セラミックパターンの厚みｔ１を導体パターンの厚みｔ２よりも厚くした試料Ｎｏ．７、８では、同一厚みの場合に比較してＨＡＬＴでのショート発生時間が長くなり信頼性が向上した。
【００８５】
また、Ｂ工程を用いて作製した試料Ｎｏ．９〜１１においても、Ａ工程を用いて作製した試料と同等の密着不良やデラミネーション発生率となり、静電容量のばらつきやＨＡＬＴも良好な結果であった。
【００８６】
一方、導体パターン周囲に離間して相似形状のセラミックパターンを形成し、Ｄ２／Ｄ１比を１．４とした試料Ｎｏ．６では、母体積層体の切断後に密着不良が見られ、焼成後および熱衝撃試験後にもデラミネーションが多発した。
【００８７】
【発明の効果】
以上詳述したとおり、本発明によれば、セラミックグリーンシート上に形成した導体パターンに隣接してセラミックパターンを形成し、この上面に再びセラミックグリーンシートを重ね合わせる工程を用い、かつ、導体パターンの外縁とセラミックパターンの内縁との間隔Ｄ１よりも、導体パターンの外角縁とセラミックパターンの内角縁との間隔Ｄ２を狭くすることにより、導体パターンの外角縁とセラミックパターンの内角縁との隙間にセラミックパターンが埋まり易くなり、導体パターンの外角縁付近におけるセラミックパターンによるセラミックグリーンシート同士を接着する面積が大きくなる。このため、この領域におけるセラミックグリーンシート間の密着不良やデラミネーションを防止できる。また、上記の逐次積層工法を用いることにより静電容量のばらつきを低減でき、絶縁信頼性を高めることができる。
【図面の簡単な説明】
【図１】本発明の、導体パターンを形成した後にセラミックパターンを形成し、逐次積層工程を行い、セラミック積層体を製造するための工程図である。
【図２】セラミックグリーンシート上に形成された導体パターンおよびセラミックパターンの配置を示す斜視図である。
【図３】（ａ）は導体パターンを印刷するスクリーンパターンの模式図、（ｂ）はセラミックパターンを印刷するスクリーンパターンの模式図である。
【図４】図１のセラミック積層体の製法において、キャリアフィルムのついたセラミックグリーンシートを用い、重ね合わせ後に剥離する工程を具備する工程を示す工程図である。
【図５】本発明の、セラミックパターンを形成した後に導体パターンを形成し、逐次積層を行い、セラミック積層体を製造するための工程図である。
【図６】従来の、セラミックグリーンシート上に導体パターンのみを形成し、逐次積層を行い、セラミック積層体を製造するための工程図である。
【図７】従来の、予めセラミックグリーンシート上に導体パターンおよびセラミックパターンを形成したものを、一括積層を行い、セラミック積層体を製造するための工程図である。
【図８】（ａ）従来のセラミックグリーンシート上に形成された導体パターンに乗り上げたセラミックパターンを示す断面模式図である。
（ｂ）従来のセラミックグリーンシート上に形成されたセラミックパターンに乗り上げた導体パターンを示す概略斜視図である。
【図９】（ａ）従来のセラミックグリーンシート上に形成された導体パターンに離間して形成されたセラミックパターンを示す断面模式図である。
（ｂ）従来のセラミックグリーンシート上に形成された導体パターンに離間して形成されたセラミックパターンを示す概略斜視図である。
【符号の説明】
１ 支持体
３ａ、３ｂ セラミックグリーンシート
５ 導体パターン
７ セラミックパターン
１４ 母体積層体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a ceramic laminate, and more particularly to a method for producing a ceramic laminate in which a ceramic green sheet and a conductor pattern are laminated in a multilayer manner, such as a wiring board and a multilayer ceramic capacitor.
[0002]
[Prior art]
In recent years, with the downsizing of electronic devices and high-density mounting, wiring boards and multilayer ceramic capacitors in which a conductor pattern is formed in a ceramic multilayer body are required to be small and thin and have high dimensional accuracy. For this reason, for example, in multilayer ceramic capacitors, ceramic green sheets and conductor patterns are being made thinner and multi-layered for smaller and higher capacity.
[0003]
Usually, such a multilayer ceramic capacitor is formed by first printing a conductive paste on the surface of a ceramic green sheet to form a plurality of rectangular conductor patterns, and then stacking a plurality of ceramic green sheets on which the conductor patterns are formed. The base laminate is formed by batch stacking, and the base laminate is further cut and fired at a predetermined position.
[0004]
However, as described above, in the manufacturing method using the process of forming a conductor pattern on the surface of the ceramic green sheet or the process of laminating a plurality of ceramic green sheets on which a conductor pattern has been formed in advance, the ceramic green sheet to be used is extremely Due to its thinness, there is a problem in that the ceramic green sheet is wrinkled during printing or during lamination, and after lamination, delamination tends to occur between the ceramic green sheet and the conductor pattern due to the space that can be wrinkled. It was.
[0005]
Therefore, what is disclosed in Patent Document 1 is known as a solution to such a problem. According to the manufacturing method disclosed in Patent Document 1, as shown in FIG. 6, an extremely thin ceramic green sheet 53b having good adhesion is superposed on the surface of a normal ceramic green sheet 53a placed on a support 51. Next, a conductive paste 55 is printed on the surface of the ultrathin ceramic green sheet 53b with good adhesion to form a conductor pattern 55, and then the ultrathin ceramic green sheet 53b with good adhesion is formed. An extremely thin ceramic green sheet 53b with good adhesion is again overlaid so as to cover the formed conductor pattern 55. Then, the base laminate 63 is formed by repeating the step of forming the conductor pattern 55 and the step of superimposing the ultrathin ceramic green sheet 53b having good adhesion. That is, it is described that the use of the sequential lamination process can prevent wrinkles of the ceramic green sheets 53a and 53b and the delamination generated in the base laminated body 63, which are problems in the collective lamination process.
[0006]
In recent years, as the ceramic green sheets 53a and 53b are made thinner and multi-layered, efforts have been made to eliminate steps due to the thickness of the conductor pattern 55 formed on the ceramic green sheets 53a and 53b (for example, Patent Document 2).
[0007]
In the method for manufacturing a ceramic laminate disclosed in Patent Document 2, a ceramic pattern 85 having the same height as the conductor pattern 83 formed on the main surface of the ceramic green sheet 81 is formed as shown in FIG. Accordingly, the step due to the thickness of the conductor pattern 83 can be substantially eliminated, and the ceramic green sheets 81 can be laminated in a state where the thickness of the conductor pattern 83 is not affected.
[0008]
Further, in such a method for producing a ceramic laminate, a conductor pattern 83 and a ceramic pattern 85 are formed on the main surface of the ceramic green sheet 81, and then a plurality of conductor patterns 83 and ceramic patterns 85 are formed. It is described that the base laminate 86 is formed by laminating ceramic green sheets 81 at once.
[0009]
[Patent Document 1]
Japanese Patent Publication No. 8-4045
[Patent Document 2]
JP 2000-311831 A
[0010]
[Problems to be solved by the invention]
However, even when the manufacturing method disclosed in Patent Document 1 is used, the thickness of the ceramic green sheets 53a and 53b is so thin that there is no difference in thickness between the ceramic green sheets 53a and 53b used and the conductor pattern 55. However, there is still a problem that the delamination generated in the base laminated body 63 and the cut laminated molded body cannot be eliminated due to the increase in the number of layers, which causes the step difference due to the conductor pattern 55.
[0011]
Moreover, in the manufacturing method disclosed in Patent Document 2 above, in the manufacturing method in which the conductor pattern 83 and the ceramic pattern 85 are in contact with each other, the screen printing accuracy for forming the ceramic pattern 85 is usually about 30 to 200 μm, There is a problem that a part of the ceramic pattern 85 rides on the conductor pattern 83 due to such a printing misalignment, leading to a result of promoting a step difference.
[0012]
Furthermore, in order to meet the demands for lowering the cost of ceramic laminates such as multilayer ceramic capacitors, the area of the workpiece (base laminate before cutting into a ceramic laminate) has been increased in the manufacturing process. For this reason, the problem of misregistration due to printing is becoming more and more apparent.
[0013]
Therefore, in order to avoid such a problem of positional deviation of the ceramic pattern 85 due to printing, as shown in FIGS. 8A and 8B, the ceramic pattern 85 is formed from the conductor pattern 83 formed on the ceramic green sheet 81. A manufacturing method in which the layers are formed separately can be considered.
[0014]
In such a manufacturing method, although the positional deviation of the ceramic pattern 85 due to printing can be suppressed, as apparent from FIGS. 9A and 9B, the ceramic pattern 85 is opened in a similar shape around the conductor pattern 83. Therefore, the distance d2 between the corner edge 89 of the conductor pattern 83 and the corner portion 91 of the ceramic pattern 85 facing the position outside the corner edge 89 is equal to the outer edge 93 of the conductor pattern 83 and its outer edge. It is wider than the distance d1 with the inner edge 95 of the ceramic pattern 85 facing 93.
[0015]
In general, the ceramic green sheet 81 on which the conductor pattern 83 and the ceramic pattern 85 are formed is laminated and heated and integrated with pressure. As described above, the corner edge 89 of the conductor pattern 83 and the ceramic pattern are integrated. Since the gap 87 between the 85 corners 91 is larger than the other parts, the ceramic pattern 85 is not easily buried even by pressurization and heating at the time of stacking. Adhesiveness with the laminated ceramic green sheets 81 tends to decrease. Moreover, since the vicinity of the corner 91 of the ceramic pattern 85 is close to the region where the cutting line intersects when the base laminate 63 is cut into individual pieces, the laminate interface is easy to peel off at the time of cutting, and delamination occurs after firing. There was a problem that it was easy to do.
[0016]
Accordingly, an object of the present invention is to provide a method for producing a ceramic laminate capable of eliminating a step due to a conductor pattern formed on a ceramic green sheet and preventing poor adhesion between ceramic green sheets and delamination after firing. And
[0017]
[Means for Solving the Problems]
The method for producing a ceramic laminate of the present invention includes: (a) a step of placing a ceramic green sheet on a support;
(B) forming a rectangular conductor pattern on the surface of the ceramic green sheet;
(C) superimposing another ceramic green sheet on the upper surface of the ceramic green sheet on which the conductor pattern is formed;
(D) repeating steps (b) and (c) to form a base laminate in which the ceramic green sheets and the conductor patterns are alternately laminated;
(E) cutting the base laminate at a predetermined position to form a laminate formed body;
In the process for producing a ceramic laminate comprising:
A ceramic pattern is formed in a portion surrounding the region where the conductor pattern is formed on the main surface of the ceramic green sheet of the base laminate, and the outer edge of the conductor pattern is substantially parallel to the outer edge of the conductor pattern. When the distance between the inner edge of the ceramic pattern is D1 and the shortest distance between the outer corner edge of the conductor pattern and the inner corner edge of the ceramic pattern located outside the outer corner edge is D2, the relationship of D1 ≧ D2 is established. It is characterized by satisfaction.
[0018]
Moreover, in the manufacturing method of the said ceramic laminated body, it is desirable to satisfy the relationship of D2 / D1 <= 0.8.
[0019]
According to this manufacturing method, since the ceramic pattern is formed adjacent to the conductor pattern formed on the ceramic green sheet, even when a thin ceramic green sheet is used, the adhesion of the ceramic green sheet Therefore, the level difference due to the conductor pattern can be easily reduced without considering the characteristics.
[0020]
Further, the gap between the corner edge of the conductor pattern and the corner portion of the ceramic pattern is narrowed compared to the distance between the linear outer edge of the conductor pattern and the linear inner edge of the ceramic pattern. The ceramic pattern is easily buried in the gap between the corner edge and the corner of the ceramic pattern. For this reason, the adhesiveness between the ceramic pattern buried in the gap and the ceramic green sheet laminated on the upper surface side can be improved.
[0021]
In addition, since the adhesion at the corners of the ceramic pattern is increased, it is possible to suppress peeling of the lamination interface when the laminate is cut into individual pieces, and it is possible to prevent the occurrence of delamination even after firing.
[0022]
In the manufacturing method of the ceramic laminate, it is desirable that the relationship of t1> t2 is satisfied, where the thickness of the ceramic pattern is t1 and the thickness of the conductor pattern is t2.
[0023]
By making the thickness of the ceramic pattern thicker than the thickness of the conductor pattern in this way, the suction surface of the suction head used at the time of lamination contacts only the ceramic pattern and does not contact the conductor pattern. It is possible to make it difficult to mark the pattern by the head. For this reason, since a conductor pattern does not extend to the area | region which should be insulated originally, the insulation failure and short circuit of a ceramic laminated body can be prevented.
[0024]
Moreover, in the temporary laminated body produced on such conditions, since a clearance gap is easy to be formed between a conductor pattern and a ceramic green sheet, the attraction at the time of lamination | stacking increases and the adhesiveness of a base laminated body can be improved.
[0025]
In the method for producing the ceramic laminate, it is desirable to form the ceramic pattern after forming the conductor pattern. The conductive pattern is colored because it contains metal powder, and since the ceramic powder is usually white, the color contrast between the conductive pattern and the ceramic green sheet is easy to attach. The pattern printing position of the ceramic pattern to be formed later can be easily made.
[0026]
In the method for manufacturing a ceramic laminate, the base laminate is formed with a conductor pattern on the inner side of the ceramic pattern after forming a ceramic pattern in a portion surrounding a region where the conductor pattern is formed on the main surface of the ceramic green sheet. It is desirable to be manufactured.
[0027]
That is, by forming the enclosure with the ceramic pattern first, the periphery of the conductor pattern is surrounded by the ceramic pattern, and even when printed with a low-viscosity conductor paste, bleeding can be suppressed. For example, a multilayer ceramic capacitor Variations in capacitance and short circuit can be prevented.
[0028]
In the method for producing a ceramic laminate, the ceramic green sheet is obtained by laminating a carrier film, and after the ceramic green sheet is overlaid on the upper surface of the ceramic green sheet on the support, the carrier film is peeled off. It is desirable to comprise. That is, when the ceramic green sheets are sequentially laminated as in the present invention, the ceramic green sheets are supported by the carrier film on one side thereof when printing both patterns or the ceramic green sheets. Wrinkles due to pressure heating or the like can also be suppressed when the layer is overlaid on the lower conductor pattern and the ceramic pattern.
[0029]
In addition, when the carrier film is bonded to the pressure surface side in this way, the lamination head used when the ceramic green sheets are stacked and the ceramic green sheet are in contact with each other via the carrier film. The ceramic green sheet can be transmitted gently, and the alteration or the like due to heat on the upper surface side of the ultra-thin ceramic green sheet with good adhesion is suppressed, and the homogeneity of the ceramic green sheet can be maintained. Furthermore, it is possible to prevent dust from adhering to the ceramic green sheet.
[0030]
In the method for producing the ceramic laminate, it is desirable that the relationship of t2 / t3 ≧ 0.5 is satisfied, where the thickness of the conductor pattern in step (c) is t2 and the thickness of the ceramic green sheet is t3. According to the present invention, the level difference due to the conductor pattern formed on the ceramic green sheet can be eliminated. In particular, the ceramic green sheet is thinned so that there is no difference in thickness from the thickness of the conductor pattern as described above. It can be suitably used in some cases.
[0031]
In the manufacturing method of the ceramic laminate, it is desirable that the peripheral portion of the ceramic pattern is formed by an inclined surface having an angle of 0.5 ° or more with respect to the main surface of the ceramic green sheet. By setting the angle of the inclined surface at the peripheral portion of the ceramic pattern to be equal to or more than the above-mentioned angle, it is possible to suppress the spreading and running of the conductor paste during printing, and to further reduce the variation in the effective area of the conductor pattern.
[0032]
Moreover, in the method for producing the ceramic laminate, it is desirable that the ceramic component in the ceramic green sheet and the ceramic component in the ceramic pattern are composed of substantially the same composition, and further, in the method for producing the ceramic laminate, It is desirable that the conductor pattern becomes an internal electrode layer of the multilayer ceramic capacitor after firing.
[0033]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing a ceramic laminate of the present invention is preferably applied to, for example, a multilayer ceramic capacitor that is one of electronic components. Therefore, the following description will be given based on the process diagram of the method for manufacturing the ceramic laminate shown in FIG.
[0034]
As shown in FIG. 1A, first, a plurality of ceramic green sheets 3a are placed on a support 1 to form an electrodeless portion 4a having a predetermined thickness that becomes a margin portion of the multilayer ceramic capacitor.
[0035]
As the ceramic green sheet 3a of the present invention, for example, a mixture of ceramic powder, an organic binder, and a solvent for dissolving the organic binder is preferably used.
[0036]
As ceramic powder, for example, BaTiO _Three Is preferably used. Moreover, you may add glass powder as a well-known additive and sintering auxiliary agent for improving reduction resistance.
[0037]
Further, the thickness of the ceramic green sheet 3a is desirably 5 μm or less, particularly 1.5 to 4 μm, for reasons of small size and large capacity.
[0038]
Next, as shown in FIG. 1B, a conductor paste is printed on one main surface of the uppermost layer of the laminated ceramic green sheets 3a to form a plurality of rectangular conductor patterns 5 spaced apart at equal intervals. To do.
[0039]
Here, the thickness t2 of the conductor pattern 5 is desirably 3 μm or less, particularly 1 μm or less from the viewpoint of miniaturization and high reliability of the capacitor. Furthermore, the relationship between the thickness of the ceramic green sheet 3a and the conductor pattern 5 is such that t2 / t3 ≧ 0.5 when the thickness of the conductor pattern 5 is t2 and the thickness of the ceramic green sheets 3a and 3b is t3. The production method of the present invention is particularly suitable when a thickness difference is formed so that the effect of the level difference due to the conductor pattern 5 becomes large enough. The t2 / t3 ratio is more preferably 0.7 or more.
[0040]
As the conductive paste used in the production method of the present invention, one containing metal particles, an organic solvent, and an organic binder soluble in the organic solvent is suitably used.
[0041]
As the metal particles, at least one kind of metal particles selected from the group of Ni, Co, and Cu is preferable. However, since the metal firing temperature coincides with the firing temperature of a general insulator, and Ni is low in cost. Is desirable. Moreover, it is preferable to mix and use fine ceramic powder as solid content in order to suppress the sinterability of the conductor pattern 5 other than metal particles.
[0042]
Furthermore, the organic paste and the organic solvent of the conductor paste can adopt the same conditions as the printing of the ceramic paste, and the volatilization rate of the organic binder from the surface of the ceramic green sheet 3a is matched. Is preferably the same composition as the ceramic paste. And in this invention, it is preferable that the conductor pattern 5 formed in this way becomes an internal electrode layer of the multilayer ceramic capacitor which is one of the electronic components.
[0043]
Next, as shown in FIG. 1C, a ceramic paste 7 is printed on a portion surrounding the conductor pattern 5 to form a ceramic pattern 7.
[0044]
FIG. 2 is a schematic perspective view showing the ceramic pattern 7 formed on the ceramic green sheet 3 a so as to be separated between the conductor patterns 5. As shown in FIG. 2, a predetermined distance L is formed on the ceramic green sheet 3a. ₁ The conductor pattern 5 formed in a rectangular shape is rectangular, while the ceramic pattern 7 is formed so as to surround the conductor pattern 5, but the shape of the opening 6 is a substantially similar shape with rounded corners. It has become. In this case, the conductor pattern 5 and the ceramic pattern 7 are formed at a predetermined interval.
[0045]
That is, the distance between the linear outer edge 9 of the conductor pattern 5 and the inner edge 10 of the ceramic pattern 7 facing the outer edge 9 on the straight line of the conductor pattern 5 is D1, and the outer corner edge 11 of the conductor pattern 5 is When the distance between the ceramic pattern 7 located outside the outer corner edge 11 and the inner corner edge 13 is D2, it is important to satisfy the relationship of D1 ≧ D2.
[0046]
That is, in the ceramic pattern 7 of the present invention, the inner corner edge 13 is formed at the outer position facing one outer corner edge 11 of the conductor pattern 5 so as to have, for example, two obtuse angles.
[0047]
The ratio D2 / D1 is preferably in the range of 0 to 0.8 because the ceramic pattern 7 is likely to be buried in the gap between the conductor pattern 5 and the ceramic pattern 7, and in particular, 0.1 to 0. A range of .5 is more desirable.
[0048]
In addition, the inner corner edge 13 of the ceramic pattern 7 may be curved instead of square in that the area of the ceramic pattern 7 is easy to expand, and the ceramic pattern 7 positioned outside the outer corner edge 11 of the conductor pattern 5 Furthermore, the ceramic pattern 7 can be expanded in the direction of the inner edge 10, so that the adhesion with the ceramic green sheet 3 a laminated on the upper surface side where the ceramic pattern 7 is formed can be further enhanced. In this case, it is preferable that the ceramic pattern 7 formed in a curved shape is in contact with the corner edge 11 of the conductor pattern 5 so as not to run over. In this case, the D2 / D1 ratio is zero.
[0049]
In addition, the distance D1 is 30 μm or more because the position accuracy margin between the conductor pattern 5 and the ceramic pattern 7 is maintained and a high-accuracy pattern is formed even if a positional deviation occurs during printing. When pressed, the range of 30 to 150 μm is more desirable because it suppresses burying of the ceramic green sheet 3a between both patterns and suppresses deformation of the ceramic laminate.
[0050]
When a slight gap is formed between the conductor pattern 5 and the ceramic pattern 7 in this way, when the ceramic green sheet 3a formed with the conductor pattern 5 and the ceramic pattern 7 is multilayered to form a ceramic laminate, When temporarily laminated, the air stored between the ceramic green sheets 3a can be effectively degassed during pressurization, and adhesion failure before firing and delamination after firing can be suppressed.
[0051]
The ceramic powder used in this ceramic paste can be either the powder composition of the ceramic green sheet 3a or a different powder composition, but the reason for matching the firing shrinkage rates of the ceramic green sheet 3a and the ceramic pattern 7 is the same. Therefore, it is desirable that the ceramic paste has substantially the same ceramic powder composition as the ceramic slurry forming the ceramic green sheet 3a.
[0052]
In this case, the conductor paste containing the metal powder is colored, and since the color contrast with the ceramic green sheets 3a and 3b is large, the conductor pattern can be printed with good recognizability based on the conductor pattern 5. 5 is preferably formed before the ceramic pattern 7.
[0053]
FIG. 3A is a schematic perspective view of a screen used for printing the conductor paste. As shown in FIG. 3A, as the screen 21 for printing the above-described conductor paste, a pattern having a plurality of portions provided with the resist layer 22 and a plurality of openings not provided is preferably used.
[0054]
On the other hand, FIG. 3B is a schematic perspective view of the screen 25 used for printing the ceramic paste. As shown in FIG. 3B, the screen 25 for printing the ceramic paste as described above needs to form the ceramic pattern 7 so as to surround the conductor pattern 5 described above. A pattern almost opposite to the screen 21 used for printing is used.
[0055]
In this case, a screen in which a substantially rectangular resist layer 27 is formed on the screen 25 at equal intervals is preferably used.
[0056]
By using such a screen 25, the ceramic pattern 7 having an opening having a substantially similar shape larger in area than the conductor pattern 5 is formed, and the outer corner edge 11 of the conductor pattern 5 and the inner corner edge 13 of the ceramic pattern 7 are The corner portion of the substantially rectangular resist layer 27 formed on the screen 25 is dropped so that the distance D2 is smaller than the distance D1 between the outer edge 9 of the conductor pattern 5 and the inner edge 10 of the ceramic pattern 7. Is used. The width of the outer corner edge 11 of the conductor pattern 5 and the inner corner edge 13 of the ceramic pattern 7 is adjusted by changing the area of the corner to be dropped. The thickness t1 of the ceramic pattern 7 is adjusted by changing the thickness of the resist layer 27 applied to the screen 25.
[0057]
The ceramic pattern 7 is preferably substantially the same thickness as the conductor pattern 5, but when the ceramic pattern 7 is formed apart from at least a part of the conductor pattern 5, the adsorption used at the time of lamination is used. Since the thickness of the ceramic pattern 7 is t1 and the thickness of the conductor pattern 5 is t2 in that the deformation of the conductor pattern 5 by the head can be suppressed, the t1 / t2 ratio is in the range of 1.05 to 1.2. Is more desirable.
[0058]
Next, as shown in FIG. 1D, on the upper surface side of the ceramic green sheet 3a on which the conductor pattern 5 and the ceramic pattern 7 are formed as described above, the conductor pattern 5 and the ceramic pattern 7 are covered. Another ceramic green sheet 3b is overlaid so that the conductor pattern 5, the ceramic pattern 7, and the ceramic green sheet 3b are brought into close contact with each other.
[0059]
Thereafter, the steps of FIGS. 1B to 1D are repeated so that the desired number of layers is obtained. Finally, the ceramic green sheet 3a is again used to form the steps in FIG. 1A. The base laminate 14 is formed by forming the electrodeless portion 4b having the same thickness.
[0060]
As described above, the present invention is a method of forming the conductive pattern 5 and the ceramic pattern 7 on the upper surface of the ceramic green sheets 3a or 3b one after another by screen printing as described above. In this respect, it is difficult to include misalignment at the time of lamination as compared to a method of preparing a plurality of ceramic green sheets 3a and 3b in which conductor patterns 5 and ceramic patterns 7 are previously formed and laminating them at once. 14, the positional accuracy of the conductor pattern 5 and the ceramic pattern 7 in FIG. 14 is only a positional deviation of the printing accuracy, so that the stacking accuracy is improved, the capacity variation can be reduced, and the side margin and end margin can be reduced. Can cope with downsizing of the ceramic laminate.
[0061]
In the production method of the present invention, as shown in FIG. 4, the ceramic green sheets 3 a and 3 b are preferably a laminate of the carrier film 20. In this case, the ceramic green sheet 3 a with the carrier film 20 is attached. The carrier film 20 is peeled after overlapping 3b. According to this method, since the ceramic green sheets 3 a and 3 b are supported by the carrier film 20, the ceramic green sheets 3 a and 3 b are ceramics even in the case where the ceramic green sheets 3 a and 3 b are adhered to each other by pressurization and heating after being superimposed on the upper surface side of the conductor pattern 5 or ceramic pattern 7. The elongation and deformation of the green sheets 3a and 3b can also be suppressed. Moreover, since this method does not adsorb the ceramic green sheets 3a and 3b themselves, defects in the ceramic green sheets 3a and 3b can be prevented.
[0062]
Further, as shown in FIGS. 5A to 5E, in the manufacturing method of the present invention, the base laminate 14 is a portion surrounding a region where the conductor pattern 5 is formed on the main surface of the ceramic green sheets 3a and 3b. Alternatively, the conductor pattern 5 can be formed inside the ceramic pattern 7 after the ceramic pattern 7 is formed.
[0063]
In this case, the angle of the inclined surface of the ceramic pattern peripheral portion is set to be smaller than that of the ceramic green sheet for the reason that the conductor pattern 5 formed after the ceramic pattern 7 is prevented from being climbed during printing and the spread of the pattern due to bleeding is prevented. The angle is preferably 0.5 ° or more with respect to the main surface, and in particular, the angle is preferably 1 to 40 °.
[0064]
1 (e1) is a cross-sectional view of the base laminate 14 on the side margin side, and FIG. 1 (e2) is a cross-sectional view on the end margin side. As shown in the figure, the base laminate 13 is cut at a dotted line C to form a laminate compact, and then the laminate compact is fired under a predetermined atmosphere and temperature to form an external conductor. Thus, a multilayer ceramic capacitor having a ceramic layer and an internal electrode layer is formed.
[0065]
Furthermore, according to this manufacturing method, the formation accuracy of the conductor pattern 5 and the ceramic pattern 7 is improved, the variation in capacity can be reduced, and even if the number of layers is increased, the formation accuracy of the conductor pattern 5 is not affected. It is possible to realize a high lamination and large size of the ceramic laminate.
[0066]
【Example】
A multilayer ceramic capacitor which is one of ceramic laminates was produced as follows.
[0067]
The ceramic green sheet is BaTiO _Three A ceramic slurry was prepared by adding an organic binder and an organic solvent to a ceramic powder containing as a main component, and formed into a film with a thickness of 2 μm on a carrier film using a die coater method.
[0068]
On the other hand, a part of the ceramic slurry was pulverized, and these ceramic powders, an organic binder for paste and an organic solvent were kneaded with three rolls to prepare a ceramic paste.
[0069]
The conductor paste was prepared by pasting Ni powder having an average particle size of 0.2 μm, the organic binder and the organic solvent used in the ceramic paste in the same manner as the ceramic paste.
[0070]
Next, a plurality of obtained ceramic green sheets were placed on a support, and a rectangular conductor pattern was formed as step A using a screen printing device on the main surface. Next, a ceramic paste is printed and dried using a predetermined printing screen so that the conductor patterns formed on the ceramic green sheet are spaced apart by the distances D1 and D2 shown in Table 1, and the ceramic is formed together with the conductor pattern. A pattern was formed. In this case, the thickness of the conductor pattern was 1.4 μm. The inclined surface of the ceramic pattern was adjusted by the viscosity of the ceramic paste and the inclination angle of the resist. The inclination angle was 4 °.
[0071]
Next, the ceramic green sheet was again overlaid on the upper surface of the ceramic green sheet on which the ceramic pattern was applied and formed together with this conductor pattern, and this was repeated 300 times to set the number of layers expressing the capacitance to 300 layers. Further, 10 ceramic green sheets each having no conductor pattern and ceramic pattern formed thereon were laminated thereon, and a first pressurizing press was performed to form a base laminate.
[0072]
Next, as step B, a ceramic pattern having the shape of the present invention is printed first, then a conductor pattern is formed in the ceramic pattern, and lamination is performed by the same method as in step A above, so that the base laminate is obtained. Was made. In the A process and the B process, a method of peeling the carrier film every time the ceramic green sheets were overlapped was used.
[0073]
Next, the matrix laminate produced in these A and B steps was cut into a lattice shape to obtain a laminate compact. Thereafter, de-bye treatment was performed by heating to 500 ° C. in the air at 250 ° C. or in a weakly reducing atmosphere.
[0074]
Furthermore, the laminated body after deburied is fired in a reducing atmosphere at 1250 ° C. for 2 hours, and further subjected to a reoxidation treatment at 900 ° C. for 4 hours in a weakly oxidizing atmosphere. I got the body. After firing, Cu paste was baked at 900 ° C. on the end face of the ceramic laminate body, and further Ni / Sn plating was performed to form external conductors alternately connected to the internal electrode layers.
[0075]
For evaluation, first, after printing, the distance D1 between the outer edge of the conductor pattern and the inner edge of the ceramic pattern substantially parallel to the outer edge of the conductor pattern, and the outer corner edge of the conductor pattern and the outer edge of the outer corner edge. The distance D2 from the inner corner edge of the ceramic pattern to be measured, the thickness t1 of the ceramic pattern, and the thickness t2 of the conductor pattern were measured using a non-contact type surface roughness meter (laser displacement meter).
[0076]
Further, each of the 100 laminated molded products before firing was observed with a stereomicroscope to evaluate adhesion failure.
[0077]
Furthermore, with regard to delamination, 100 laminated ceramic capacitors after firing and after thermal shock test (at 280 ° C. for 2 seconds) were polished from the end face and side face, respectively, and the number of occurrences of delamination around the inner conductor Evaluated.
[0078]
Next, the variation in capacitance was calculated from the measured capacitance value of 100 laminated ceramic capacitors after firing. At the same time, the short-circuit rate was determined from the capacitance measurement.
[0079]
Further, HALT (accelerated life test) was performed on 50 ceramic laminates on which external electrodes were formed. The test conditions were 150 ° C. and 40 V, and the time until the first short circuit occurred was evaluated.
[0080]
On the other hand, as a comparative example, a ceramic laminate similar to the present invention was produced using a rectangular conductor pattern formed and spaced apart from the periphery to form a similar ceramic pattern. In this case, the distance between the outer corner edge of the conductor pattern and the inner corner edge of the ceramic pattern is wider than the distance between the outer edge of the conductor pattern and the inner edge of the ceramic pattern. These results are shown in Table 1.
[0081]
[Table 1]

[0082]
As is apparent from the results in Table 1, the process A in which the conductor pattern according to the present invention is formed and then the ceramic pattern is formed and sequentially laminated is used, and the distance D1 between the outer edge of the conductor pattern and the inner edge of the ceramic pattern is used. In Sample No. 2, the distance D2 between the outer corner edge of the conductor pattern and the inner corner edge of the ceramic pattern is equal or narrower. In 1 to 5, there was a sample in which delamination was observed after firing and after the thermal shock test, but the adhesion failure in the molded body after cutting the base molded body was 0%. Further, the variation in capacitance was as good as 1.6% or less.
[0083]
In addition, the sample No. in which the ratio of the intervals was D2 / D1 ≦ 0.8. In Nos. 1 to 4, the delamination occurrence rate after firing was 1%, and further, Sample Nos. 0.1 ≦ D2 / D1 ≦ 0.5 were set. In 2-3, the delamination occurrence rate after the thermal shock test was 0%.
[0084]
Furthermore, the sample No. 1 in which the thickness t1 of the ceramic pattern was made larger than the thickness t2 of the conductor pattern. 7 and 8, the short occurrence time in HALT was longer and the reliability was improved as compared with the case of the same thickness.
[0085]
In addition, Sample No. 9 to 11 also had the same adhesion failure and delamination occurrence rate as the sample produced using the A process, and the variation in capacitance and HALT were also good results.
[0086]
On the other hand, sample Nos. 1 and 2 having a D2 / D1 ratio of 1.4 were formed by forming a similar ceramic pattern apart around the conductor pattern. In No. 6, adhesion failure was observed after the matrix laminate was cut, and delamination occurred frequently after firing and after the thermal shock test.
[0087]
【The invention's effect】
As described above in detail, according to the present invention, the step of forming a ceramic pattern adjacent to the conductor pattern formed on the ceramic green sheet and overlaying the ceramic green sheet again on this upper surface, The gap D2 between the outer corner edge of the conductor pattern and the inner corner edge of the ceramic pattern is made narrower than the gap D1 between the outer edge and the inner edge of the ceramic pattern, so that the ceramic is formed in the gap between the outer corner edge of the conductor pattern and the inner corner edge of the ceramic pattern. The pattern is easily buried, and the area for bonding the ceramic green sheets by the ceramic pattern in the vicinity of the outer corner edge of the conductor pattern is increased. For this reason, poor adhesion and delamination between the ceramic green sheets in this region can be prevented. Further, by using the above sequential lamination method, variation in capacitance can be reduced, and insulation reliability can be improved.
[Brief description of the drawings]
FIG. 1 is a process diagram for producing a ceramic laminate by forming a ceramic pattern after forming a conductor pattern and sequentially performing a lamination process according to the present invention.
FIG. 2 is a perspective view showing an arrangement of conductor patterns and ceramic patterns formed on a ceramic green sheet.
3A is a schematic diagram of a screen pattern for printing a conductor pattern, and FIG. 3B is a schematic diagram of a screen pattern for printing a ceramic pattern.
4 is a process diagram showing a process including a process of peeling after superposition using a ceramic green sheet with a carrier film in the method of manufacturing the ceramic laminate of FIG.
FIG. 5 is a process diagram for producing a ceramic laminate by forming a conductor pattern after forming a ceramic pattern and sequentially laminating the ceramic pattern of the present invention.
FIG. 6 is a process diagram for producing a ceramic laminate by forming only a conductor pattern on a ceramic green sheet and sequentially laminating.
FIG. 7 is a process diagram for manufacturing a ceramic laminate by performing batch lamination of conventional ceramic green sheets previously formed with a conductor pattern and a ceramic pattern.
FIG. 8A is a schematic cross-sectional view showing a ceramic pattern on a conductor pattern formed on a conventional ceramic green sheet.
(B) It is a schematic perspective view which shows the conductor pattern riding on the ceramic pattern formed on the conventional ceramic green sheet.
FIG. 9A is a schematic cross-sectional view showing a ceramic pattern formed apart from a conductor pattern formed on a conventional ceramic green sheet.
(B) It is a schematic perspective view which shows the ceramic pattern formed spaced apart from the conductor pattern formed on the conventional ceramic green sheet.
[Explanation of symbols]
1 Support
3a, 3b ceramic green sheet
5 Conductor pattern
7 Ceramic pattern
14 Matrix laminate

Claims (10)

(A) placing a ceramic green sheet on a support;
(B) forming a rectangular conductor pattern on the surface of the ceramic green sheet;
(C) superposing another ceramic green sheet on the upper surface of the ceramic green sheet on which the conductor pattern is formed;
(D) repeating steps (b) and (c) to form a base laminate in which the ceramic green sheets and the conductor patterns are alternately laminated;
(E) cutting the base laminate at a predetermined position to form a laminate formed body;
In the process for producing a ceramic laminate comprising:
A ceramic pattern is formed in a portion surrounding the region where the conductor pattern is formed on the main surface of the ceramic green sheet of the base laminate, and the outer edge of the conductor pattern is substantially parallel to the outer edge of the conductor pattern. When the distance between the inner edge of the ceramic pattern is D1 and the shortest distance between the outer corner edge of the conductor pattern and the inner corner edge of the ceramic pattern located outside the outer corner edge is D2, the relationship of D1 ≧ D2 is established. A method for producing a ceramic laminate characterized by satisfaction. The method for producing a ceramic laminate according to claim 1, wherein a relationship of D2 / D1 ≦ 0.8 is satisfied. 3. The method for manufacturing a ceramic laminate according to claim 1, wherein a relationship of t <b> 1> t <b> 2 is satisfied, where t <b> 1 is a thickness of the ceramic pattern and t <b> 2 is a thickness of the conductor pattern. The method for producing a ceramic laminate according to any one of claims 1 to 3, wherein the matrix laminate is formed with a ceramic pattern after the conductor pattern is formed. The matrix laminate is manufactured by forming a ceramic pattern in a portion surrounding a region where a conductive pattern is formed on the main surface of the ceramic green sheet, and then forming a conductive pattern inside the ceramic pattern. The manufacturing method of the ceramic laminated body in any one of Claim 1 thru | or 4. The ceramic green sheet has a carrier film attached thereto, and includes a step of peeling the carrier film after the ceramic green sheet is overlaid on the ceramic green sheet on the support. A method for producing a ceramic laminate according to any one of claims 1 to 5. 7. The relationship of t 2 / t 3 ≧ 0.5 is satisfied when the thickness of the conductor pattern in the step (c) is t 2 and the thickness of the ceramic green sheet is t 3. The manufacturing method of the ceramic laminated body of description. The ceramic laminate according to any one of claims 1 to 7, wherein the ceramic pattern peripheral part is formed by an inclined surface having an angle of 0.5 ° or more with respect to a main surface of the ceramic green sheet. The manufacturing method. The method for producing a ceramic laminate according to any one of claims 1 to 8, wherein a ceramic component contained in the ceramic green sheet and a ceramic component contained in the ceramic pattern are substantially composed of the same composition. The method for producing a ceramic laminate according to any one of claims 1 to 9, wherein the conductor pattern becomes an internal electrode layer of the multilayer ceramic capacitor after firing.

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