JP2004342683A - Method of manufacturing multilayered ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered ceramic substrate the main body of which is reduced in warping. <P>SOLUTION: A desired multilayered ceramic substrate is obtained by baking blocks showing the same warpage when the blocks are baked after the blocks are laminated upon another with a binding layer in between, so that the warping directions of the blocks may become opposite to each other, and by removing the binding layer interposed between the blocks after baking. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３８】
この結果から、全測定ポイントにおいて、（ａ）に比べ（ｂ）の方、すなわち本発明の製造方法で作製した基板の方が反りは少なくなり、また全測定ポイントの平均値も（ａ）が１．７０７ｍｍに対し（ｂ）が０．７６１ｍｍと小さく、明らかに効果があることが確かめられた。
【００３９】
次に、上述の第２の実施形態にあたる製法で、反りが抑制できる効果があることを確かめるための実験を行った。図６は、その実験内容を説明するための積層体の断面図と、測定点を示すための基板上側主面の平面図である。
【００４０】
（ａ）は、厚み３μｍの第２の拘束層５４を主面に印刷した１２０ｍｍ四方の１１枚のセラミックグリーンシート（厚み５０μｍ５１を１０枚、厚み１００μｍ５２を１枚）で配列された生の積層体の断面図である。一方、（ｂ）は、（ａ）と同じシート配列の積層体を２つ用意し、第１の拘束層となるべき１００ｍｍ×１００ｍｍの厚み１００μｍの拘束グリーンシート５５を挟んで対称に配置した生の積層体の断面図である。（ｂ）に示す通り、拘束グリーンシート５５の外周部がセラミックグリーンシートで埋められるように積層されているが、この外周部は各々１０ｍｍの長さとなるように、拘束グリーンシート５５を積層体の中心に配置した。この２つの生の積層体を約１０００℃で焼成の後、（ｂ）については基板の主面方向から２点鎖線で示す耳部１６をダイサーで切り落とし、さらに第１の拘束層を除去した上で、各々の基板の反りを計測した。（ｃ）は測定ポイントを示すための、基板を上から見た時の平面図であり、▲１▼〜▲４▼を記載した基板四隅の測定ポイントと、×を記載した基板中心部との高低差を計測した。結果は次の表２の通り。
【００４１】
【表２】

【００４２】
この結果から、全測定ポイントにおいて、（ａ）に比べ（ｂ）の方、すなわち本発明の製造方法で作製した基板の方が反りは少なくなり、また全測定ポイントの平均値も（ａ）が０．６１４ｍｍに対し（ｂ）が０．１９６ｍｍと小さく、明らかに効果があることが確かめられた。さらに拘束グリーンシート５５を挟んだ上下のブロックが、焼成中も分離されないことも確かめられた。
【００４３】
次に、上述の応用例にあたる形状の基板においても、反りが抑制できる効果があることを確かめるための実験を行った。図７は、その実験内容を説明するための積層体の断面図である。
【００４４】
（ａ）は、厚み３μｍの第２の拘束層６４を主面に印刷した１００ｍｍ四方の６枚の厚み５０μｍのセラミックグリーンシート６１で配列し、メカパンチでキャビティ形成用の貫通孔を開け、シートを除去してキャビティ１７（幅３．５ｍｍ）を形成した生の積層体の断面図である。一方、（ｂ）は、（ａ）と同じシート配列の積層体を２つ用意し、第１の拘束層となるべき１００ｍｍ四方の厚み１００μｍの拘束グリーンシート６５を挟んで対称に配置した生の積層体の断面図である。この２つの生の積層体を約１０００℃で焼成の後、（ｂ）については第１の拘束層を除去した上で、各々の基板のキャビティ底面部の高低差を計測した。
【００４５】
結果、（ａ）にあたる基板は０．１０ｍｍに対し、（ｂ）にあたる基板は０．０１ｍｍであった。これにより、キャビティを有する基板を本発明の製法で作製すれば、反りの抑えられた基板が作製できることが確かめられ、キャビティ底面部への高密度な要素部品などの実装が可能となると確認できた。
【００４６】
次に、（ｃ）は、厚み３μｍの第２の拘束層７４を主面に印刷した１００ｍｍ四方の１０枚の厚み５０μｍのセラミックグリーンシート７１で配列し、３ヶ所の溝１８（幅２００μｍ、深さ４２４μｍ）をダイサーで形成した生の積層体の断面図である。一方、（ｄ）は、（ｃ）と同じシート配列の積層体を２つ用意し、第１の拘束層となるべき１００ｍｍ四方の厚み１００μｍの拘束グリーンシート７５を挟んで対称に配置した生の積層体の断面図である。この２つの生の積層体を約１０００℃で焼成の後、（ｄ）については第１の拘束層を除去した上で、各々の基板の溝の状態を調べた。
【００４７】
結果、（ｃ）にあたる基板の溝には、基板の反りが原因として発生している割れが生じており、集合基板としての形態を維持できなかった。一方、（ｄ）にあたる基板の溝には割れが生じておらず、集合基板としての形態を維持していた。これにより、反りの抑えられる本発明の製法で作製すれば、集合基板のような深い溝を形成する場合においても溝割れしないことが確かめられた。
【００４８】
【発明の効果】
以上のように、本発明によれば、焼成時に発生する反り量が同じブロックを、拘束層を挟んだ上で、反り方向が反対になるように向かい合わせて積層・焼成・拘束層除去をすることにより、反りうねりの小さい多層セラミック基板を作製することができる。
【図面の簡単な説明】
【図１】本発明の多層セラミック基板製造方法の第１の実施形態を説明するための斜視図である。
【図２】本発明の多層セラミック基板製造方法の第２の実施形態を説明するための斜視図である。
【図３】本発明の多層セラミック基板製造方法の応用例を説明するための斜視図である。
【図４】本発明の多層セラミック基板製造方法の応用例を説明するための斜視図である。
【図５】本発明の第１の実施形態による実験内容を説明するための断面図と平面図である。
【図６】本発明の第２の実施形態による実験内容を説明するための断面図と平面図である。
【図７】本発明の応用例に示す形状の基板による実験内容を説明するための断面図である。
【符号の説明】
１１…セラミックグリーンシート
１２…（第１の拘束層となる）拘束グリーンシート
１４…第１の拘束層
１５…第２の拘束層
１６…耳部
１７…キャビティ
１８…溝
１９…セラミック層
２０…積層体
２１…第１のブロック
２２…第２のブロック
３０…焼成積層体
３１…多層セラミック基板
３２…多層セラミック基板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a multilayer ceramic substrate.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the spread of portable information terminals and computers, ceramic multilayer substrates incorporated in these electronic devices have been actively used. This multilayer substrate is generally manufactured by laminating a plurality of ceramic green sheets on which wiring circuits are mounted and firing the produced laminate in order to reduce the size of the substrate and improve the electrical characteristics. However, since the ceramic green sheet shrinks during firing, the substrate formed after firing may be warped, cracked, warped, or undulated. If there is an abnormality in the shape of the substrate, the wiring circuit mounted on the substrate is broken or becomes brittle against impact, leaving a problem in quality.
[0003]
In general, there are various causes of warpage of a substrate. For example, when a wiring circuit layer formed on a sheet and a sheet are simultaneously fired, warpage occurs due to a difference in shrinkage behavior between the two. If the wiring circuit layer is formed on the upper surface of the sheet and does not shrink more than the sheet, even if the sheet tries to shrink evenly, the surface on which the wiring circuit layer is formed becomes a barrier. Will be convex.
[0004]
When the non-shrinkage method in which the constraining layer is provided between the layers of the sheets is applied, and the arrangement of the constraining layers is not symmetrical in the thickness direction in the laminate, the restraining force in the laminate is not balanced and warpage occurs. Will be. If it is assumed that a constraining layer with a high constraining force is provided on the upper part of the laminate, even if the sheet tries to shrink evenly, the surface in contact with the constraining layer with a high constraining force becomes a barrier, so The body will bend into a convex shape.
[0005]
In order to solve such a problem, in Patent Document 1, a line at an equal distance from the front surface and the back surface of the laminate is set as a center line, and an insulating layer above and a lower insulating layer from the center line are symmetrical. It has been proposed to use substrates that are arranged and fired. Accordingly, in the firing step performed after the lamination, the warpage generated in the entire upper insulating layer is offset by the warpage generated in the entire lower insulating layer, and thus the completed substrate is not warped.
[0006]
[Patent Document 1]
JP-A-10-308584
[Problems to be solved by the invention]
However, in Patent Literature 1, although a substrate without warpage can be manufactured, the arrangement of the substrates must always be correctly symmetrical from the center, which involves a problem that the design of a desired substrate is limited.
[0008]
Accordingly, an object of the present invention is to provide a method for manufacturing a multilayer ceramic substrate that can solve the above-described problems.
[0009]
[Means for Solving the Problems]
According to the method for manufacturing a multilayer ceramic substrate according to claim 1 of the present invention, a ceramic green sheet; a green sheet preparing step of preparing a constrained green sheet that does not sinter at a sintering temperature of the ceramic green sheet; A conductor wiring forming step of forming a conductor wiring portion, a first block of the ceramic green sheet, and a ceramic green sheet, wherein the first block generates the same amount of warpage as that generated during firing. And a second constraining layer between the main surface of the first block and the main surface of the second block. A laminating step of arranging the constrained green sheets to form a laminate, a firing step of firing the laminate, and a fired lamination It is characterized by carrying out the first constraint layer removing step of removing the first constraining layer from.
[0010]
Although the above-mentioned Patent Document 1 is based on the premise that the desired arrangement of the substrates is always exactly symmetrical from the center and that the fired laminate is used as the substrate as it is, according to the present invention, the desired substrate is arranged. Says that any array can be used. There is no limitation on the arrangement of the desired substrate, and the first block that is to be the desired substrate has the same amount of warpage generated during firing, and the second block is laminated, fired, and divided with the constrained green sheet therebetween. It is good. It is more preferable that the first block and the second block have the same arrangement because the amount of warpage is the same. In this case, at least two desired substrates are obtained. However, they do not necessarily have to be in the same arrangement. For example, even if one sheet constituting the first block has a thickness of 100 μm and five sheets corresponding to the second block have a thickness of 20 μm, the arrangement is different but the amount of warpage is substantially the same. The arrangements do not have to be the same because they are identical.
[0011]
The reason for sandwiching the unsintered constrained green sheets in the firing step is to facilitate removal after firing. Although it is difficult to accurately separate the sintered layers from each other, it is easy to separate the sintered layer and the unsintered layer by a method such as immersion in water.
[0012]
Further, according to the method for manufacturing a multilayer ceramic substrate according to claim 2 of the present invention, in the laminating step, the ceramic green sheet constituting the first block, the constrained green sheet, and the second block are combined. The ceramic green sheets to be constituted are stacked and laminated in order from the lowermost layer when the laminate is formed.
[0013]
Claim 1 is a manufacturing method in which the first block and the second block are prepared in advance, and then the first block, the restrained green sheet and the second block are pressure-bonded to obtain one laminated body. Item 2 means a manufacturing method in which one layered product is obtained by stacking sequentially from the lowermost layer and finally compressing it.
[0014]
Further, according to the method for manufacturing a multilayer ceramic substrate according to the third aspect of the present invention, the second constraining layer which is not removed even after sintering constitutes the first block and the second block. The method may further include a second constraining layer forming step of forming on the main surface of the ceramic green sheet.
[0015]
According to a method of manufacturing a multilayer ceramic substrate according to a fourth aspect of the present invention, in the laminating step, the sheet arrangement of the first block and the second block is a constraint in which the first block and the second block are to be the first constraint layer. It is characterized by being arranged symmetrically with respect to the green sheet.
[0016]
As described above, the sheet arrangement of the first block and the second block is not limited to the same sheet arrangement. However, if the blocks have the same sheet arrangement, the warp amounts are necessarily equal.
[0017]
Furthermore, according to the method for manufacturing a multilayer ceramic substrate according to claim 5 of the present invention, in the laminating step, the constrained green sheet to be the first constrained layer smaller than the size of the main surface of the laminated body, The ceramic green sheets are arranged so that both end portions or outer peripheral portions are laminated with the ceramic green sheets when the laminated body is formed. Further, after the calcining step, the first constrained layer is formed from the calcined laminated body. The method further comprises the step of removing the ear portion including the ceramic layer located at both ends or the outer peripheral portion of the ear portion from the main surface direction of the fired laminate.
[0018]
When firing a laminate including a constrained green sheet of a different material from the ceramic green sheet, if the amount of warpage during firing of the ceramic green sheet is large, peeling is likely to occur from the interface where the constrained green sheet and the ceramic green sheet are in contact with each other. And may be separated during firing. If a constraining green sheet to be a first constraining layer shorter than the length of one of the vertical and horizontal sides of the main surface of the laminate is arranged and crimped, so that both ends of the constraining green sheet are filled during crimping, The ceramic sheets disposed on the main surfaces of the first block and the second block are directly pressed, so that the first block and the second block can be prevented from separating during firing.
[0019]
In addition to the above-described method, a method of preparing and arranging a small-sized ceramic green sheet to supplement the empty space at both ends of the restricted green sheet in advance may be used.
[0020]
Furthermore, if not only the both ends are filled with the ceramic sheet, but also the restraining green sheet with a shorter length in both the vertical and horizontal sides so that the entire outer peripheral part is filled with the ceramic sheet, more powerful against peeling It is preferable because it can protect.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a perspective view for explaining a first embodiment of a multilayer ceramic substrate manufacturing method of the present invention.
(Green sheet preparation process)
First, as shown in (a), a ceramic green sheet 11 and a constrained green sheet 12 that is not sintered at the firing temperature in the firing step are prepared. The constrained green sheet 12 becomes the first constrained layer 14 that is removed after the firing step.
[0022]
For example, the ceramic green sheet 11 is obtained by adding an organic vehicle including an organic binder and a solvent to a mixture of barium oxide, silicon oxide, alumina, calcium oxide and boron oxide powder, and mixing these. Obtain a slurry. This slurry can be obtained by forming a sheet having a desired thickness on a carrier film by a doctor blade method or the like and drying the sheet.
[0023]
Further, in addition to a material that produces glass at the time of firing, a composition that can be sintered at a lower temperature by previously containing a sintering aid such as glass or copper oxide or magnesium oxide may be used. .
[0024]
In addition, an inorganic compound or glass may be added for the purpose of promoting sintering, controlling shrinkage behavior, improving strength, and controlling electric characteristics of the ceramic green sheet 11, or a metal may be added as long as the insulating property of the substrate is not impaired.
[0025]
The constrained green sheet 12 is made of a material that does not sinter at the firing temperature in the firing step, for example, an alumina powder or a zirconia powder, and an organic vehicle and a plasticizer are added as in the case of the ceramic green sheet 11 described above. The slurry can be obtained by forming the slurry on a carrier film into a sheet having a desired thickness by a doctor blade method or the like, and drying the sheet.
(Second constraining layer forming step)
Next, although omitted in FIG. 1, a second constraining layer 15 which is not removed even after the firing step is formed on the main surface of the ceramic green sheet 11. The second constraining layer 15 is formed by directly printing and drying the slurry used for forming the constrained green sheet 12 described in the above-described green sheet preparation step on the main surface of the ceramic green sheet 11. Further, the slurry is not the same as the slurry described in the green sheet preparing step, and a slurry containing glass as a sintering aid may be used. Further, the slurry may be formed in a sheet shape in advance, and may be formed by placing the slurry on the main surface of the ceramic green sheet 11 in a subsequent laminating step and pressing the same.
[0026]
In this embodiment, the second constraining layer is formed directly on the main surface of the ceramic green sheet 11, but after the next conductive wiring forming step, that is, the conductive wiring is formed on the ceramic green sheet 11, and A second constraining layer may be formed thereon.
(Conductor wiring formation step)
Next, although omitted in FIG. 1, a step of forming a conductor wiring layer on the ceramic green sheet 11 on which the second constraining layer is formed is performed. The conductor wiring layer is formed by, for example, a method of screen-printing a conductive paste or attaching a metal foil, but any method may be used as long as simultaneous firing can be performed in a firing step described later. Also, a via hole or a through hole for making electrical connection between layers may be formed by providing a through hole in the layer and filling the conductive paste.
(Lamination process)
Next, as shown in (b), a first block 21 is formed so that the ceramic green sheets 11 on which the second constraining layer 15 is formed are arranged in a desired arrangement, and the first block is generated during firing. A second block 22 made of the ceramic green sheet 11 on which the second constraining layer 15 is formed, which produces the same amount of warpage as that of the first block 21 and the second block 22 which are generated during firing, is produced. The blocks 22 are arranged so that their warping directions are opposite to each other, and are laminated with the restrained green sheets 12 interposed therebetween, thereby producing a laminated body 20 as shown in (c). In the present embodiment, the second constraining layer 15 is disposed between the layers and the main surface of all the ceramic green sheets 11. However, the second constraining layer 15 may be disposed between the layers or the main surface of the specific ceramic green sheet 11. You don't have to.
[0027]
In stacking, in this embodiment, the first block 21 and the second block 22 are prepared in advance. However, a procedure of stacking from the bottom layer so as to obtain a desired arrangement of stacked bodies and finally stacking the whole is also possible. I do not care. However, regardless of the order in which the layers are laminated, the first block 21 and the second block 22 included in the resultant laminate 20 are adjusted so that the amount of warpage generated during firing is the same. In addition, it is necessary to arrange the constraining green sheets 12 so as to face each other so that the warping directions are opposite to each other. In the present embodiment, as an example in which the first block 21 and the second block 22 have the same amount of warpage, two blocks having the same sheet arrangement are stacked so as to be symmetric about the constrained green sheet 12. Case. (Baking process)
Next, although not shown in FIG. 1, the laminate 20 is fired. The firing temperature is higher than the sintering temperature of the ceramic green sheet 11 and lower than the sintering temperature of the constrained green sheet 12.
(First constraining layer removing step)
Next, as shown in (d), the first constraining layer 14 is removed from the fired laminate, and as a result, a substrate 31 and a substrate 32 including the ceramic layer 19 and the second constraining layer 15 are obtained. The removal of the first constraining layer 14 is performed using, for example, high-pressure cleaning water or cleaning water containing fine alumina powder.
[0028]
Next, although omitted in FIG. 1, a multilayer ceramic substrate is completed through a plating process, a process of mounting components to be mounted on the substrate, a process of covering a case of metal or the like, and the like. In this embodiment, since two blocks having the same sheet arrangement to be a desired substrate are overlapped, two identical multilayer ceramic substrates are completed as a result.
[0029]
FIG. 2 is a perspective view for explaining a second embodiment of the method for manufacturing a multilayer ceramic substrate of the present invention, and shows a case where a restrained green sheet smaller than the main surface size of the laminate is used. I have. The description of steps equivalent to those in FIG. 1 is omitted, and elements corresponding to the elements shown in FIG. 1 are given the same reference numerals.
(Green sheet preparation process)
First, as shown in (a), a ceramic green sheet 11 and a constrained green sheet 12 that is not sintered at the firing temperature in the firing step are prepared. As in the first embodiment, the constrained green sheet 12 becomes the first constrained layer 14 that is removed after the firing step. The materials used and the manufacturing method are the same as those in the first embodiment, but the size of the constrained green sheet 12 is smaller than the main surface size of the laminate. In the present embodiment, a sheet having one short side is manufactured so that both ends of the constrained green sheet 12 are laminated with the ceramic green sheets 11 when the laminated body is formed.
[0030]
Next, although omitted in FIG. 2, similarly to the first embodiment, a conductor wiring forming step and a second constraining layer forming step are performed.
(Lamination process)
Next, as shown in (b), the ceramic green sheet 11 and the constrained green sheet 12 on which the second constraining layer 15 is formed are laminated in the same manner as in the laminating step described in the first embodiment. However, in the present embodiment, as shown in (c), the constrained green sheets 12 are arranged so that both ends are laminated with the ceramic green sheets 11, preferably both ends are evenly spaced. In the case of the present embodiment, as shown in (b), nothing is laminated on the open spaces at both ends of the constrained green sheet 12. Even if nothing is laminated, as shown in (c), the vacant land portions at both ends are pressure-bonded so that the ceramic green sheets 11 arranged on both main surfaces of the constrained green sheet 12 are bound together. However, depending on the thickness of the constrained green sheet 12 and the area ratio between the vacant land portion and the main surface of the laminate, the vacant land portion may not be sufficiently filled and crimped. In the case where the area ratio is small, it is preferable to form a small-sized ceramic green sheet in advance to fill both end portions, to arrange them at both end portions in the laminating step, and then to perform pressure bonding.
[0031]
Also, by preparing and laminating a constrained green sheet 12 whose other side is short so that the ceramic green sheet is buried not only on both ends but also on the entire outer peripheral portion, the space between the block and the constrained green sheet 12 at the time of firing can be further improved. Although peeling can be prevented, in this case as well, it is preferable to arrange the constrained green sheets 12 such that the vertical and horizontal edges of the outer peripheral portion are evenly spaced.
(Baking process)
Next, although omitted in FIG. 2, a firing step of firing the laminate is performed.
(Ear removal process)
Next, as shown in (d), from the main surface side of the fired laminate 30 including the ceramic layers buried at both ends of the first constraining layer 14, as shown by a two-dot chain line, Along the extension of both ends of the constraining layer 14 using a dicer or the like. As a result, the ears 16 located at both ends are cut off from the fired laminate 30 as shown in FIG. When cutting by hand instead of cutting with a dicer or the like, a notch 17 may be provided in advance on a portion of the main surface of the fired laminate 30 to be cut.
(First constraining layer removing step)
Thereafter, similar to the first constraining layer removing step shown in the first embodiment, the first constraining layer 14 is removed, a plating step, a mounting step of components to be mounted on a substrate, and a step of covering a case of metal or the like. Through these steps, a multilayer ceramic substrate is completed.
[0032]
FIG. 3 is a perspective view for explaining an application example of the multilayer ceramic substrate manufacturing method of the present invention, and shows a case of manufacturing a substrate having a cavity having a thin bottom plate. FIG. 4 is also a perspective view for explaining an application example of the method for manufacturing a multilayer ceramic substrate according to the present invention. In a case where a large number of child substrates are obtained from one laminated body to be an aggregate substrate, the laminated body is easily divided. Is shown with a groove. 3 and 4, (a) corresponds to the time of lamination, (b) corresponds to after the lamination step, and (c) corresponds to the state after the first constraining layer removing step.
[0033]
Since the laminated body having the shape shown in FIGS. 3 and 4 has a portion where the thickness of the laminated body becomes thinner, the laminated body warps during firing as compared with the rectangular parallelepiped-shaped laminated body shown in FIG. Although undulation is more likely to occur, in the present invention, since blocks of the same arrangement are further laminated with the constrained green sheet 12 interposed therebetween, the thickness is further increased and fired, and warpage and undulation are caused. Occurrence is reduced.
[0034]
Next, experimental results for verifying the operation and effect of the present invention will be described.
[0035]
First, an experiment was performed to confirm that the manufacturing method according to the first embodiment described above had an effect of suppressing warpage. FIG. 5 is a cross-sectional view of the laminated body used in the experiment for explaining the contents of the experiment, and a plan view of the upper main surface of the substrate for indicating measurement points.
[0036]
(A) is an array of 12 80 mm square ceramic green sheets (10 sheets of 50 μm 41, 1 sheet of 100 μm 42 and 1 sheet of 25 μm 43) printed on the main surface with a second constraining layer 44 of 3 μm thickness. FIG. 4 is a cross-sectional view of the raw laminate that has been applied. On the other hand, (b) shows a raw laminate obtained by preparing two laminates having the same sheet arrangement as in (a) and symmetrically arranging a 100 μm-thick constrained green sheet 45 to be a first constraining layer. It is sectional drawing. After baking the two green laminates at about 1000 ° C., the first constraining layer is removed for (b), and the warpage of each of the substrates produced based on (a) and (b) is reduced. Measured. (C) is a plan view when the substrate is viewed from above, showing the measurement points. The measurement points at the four corners of the substrate described with (1) to (4) and the center of the substrate described with (x) are shown. The height difference was measured. The results are shown in Table 1 below.
[0037]
[Table 1]

[0038]
From this result, at all the measurement points, the warpage is smaller in (b), that is, the substrate manufactured by the manufacturing method of the present invention than in (a), and the average value of all the measurement points is (a). As compared with 1.707 mm, (b) was as small as 0.761 mm, and it was confirmed that there was a clear effect.
[0039]
Next, an experiment was performed to confirm that the manufacturing method according to the second embodiment described above had an effect of suppressing warpage. FIG. 6 is a cross-sectional view of the laminate for explaining the contents of the experiment, and a plan view of the upper main surface of the substrate for indicating measurement points.
[0040]
(A) is a raw laminate in which eleven 120 mm square ceramic green sheets (10 sheets having a thickness of 50 μm 51 and one sheet having a thickness of 100 μm 52) having a second constraining layer 54 having a thickness of 3 μm printed on a main surface thereof are arranged. FIG. On the other hand, (b) shows two sheets having the same sheet arrangement as in (a) prepared and symmetrically arranged with a 100 mm × 100 mm 100 μm thick constrained green sheet 55 to be the first constrained layer. It is sectional drawing of the laminated body of. As shown in (b), the constrained green sheet 55 is laminated so that the outer peripheral portion of the constrained green sheet 55 is filled with the ceramic green sheet. Centered. After firing these two green laminates at about 1000 ° C., as for (b), the ears 16 indicated by two-dot chain lines are cut off from the main surface direction of the substrate with a dicer, and the first constraining layer is removed. Then, the warpage of each substrate was measured. (C) is a plan view when the substrate is viewed from above, showing the measurement points. The measurement points at the four corners of the substrate described with (1) to (4) and the center of the substrate described with (x) are shown. The height difference was measured. The results are shown in Table 2 below.
[0041]
[Table 2]

[0042]
From this result, at all the measurement points, the warpage is smaller in (b), that is, the substrate manufactured by the manufacturing method of the present invention than in (a), and the average value of all the measurement points is (a). (B) was as small as 0.196 mm compared to 0.614 mm, and it was confirmed that there was a clear effect. Further, it was confirmed that the upper and lower blocks sandwiching the restrained green sheet 55 were not separated during firing.
[0043]
Next, an experiment was conducted to confirm that the substrate having the shape corresponding to the application example described above has an effect of suppressing the warpage. FIG. 7 is a cross-sectional view of the laminate for explaining the contents of the experiment.
[0044]
(A), a 3 mm thick second constraining layer 64 is printed on the main surface and arranged in six 100 mm square ceramic green sheets 61 having a thickness of 50 μm, and a through hole for forming a cavity is opened by a mechanical punch. It is sectional drawing of the raw laminated body which removed and formed cavity 17 (3.5 mm in width). On the other hand, (b) shows a raw laminate in which two laminates having the same sheet arrangement as in (a) are prepared and symmetrically arranged with a 100 mm square 100 μm thick green sheet 65 to be the first constraining layer. It is sectional drawing of a laminated body. After baking the two green laminates at about 1000 ° C., in (b), after removing the first constraining layer, the height difference of the bottom surface of the cavity of each substrate was measured.
[0045]
As a result, the substrate corresponding to (a) was 0.10 mm, and the substrate corresponding to (b) was 0.01 mm. Thus, it was confirmed that if a substrate having a cavity was produced by the method of the present invention, a substrate with reduced warpage could be produced, and it was confirmed that high-density element parts and the like could be mounted on the bottom surface of the cavity. .
[0046]
Next, (c) shows the arrangement of ten 50 mm thick ceramic green sheets 71 of 100 mm square with a 3 μm thick second constraining layer 74 printed on the main surface, and three grooves 18 (200 μm wide, 200 μm deep). FIG. 4 is a cross-sectional view of a raw laminate formed by using a dicer (with a thickness of 424 μm). On the other hand, (d) shows a raw sheet in which two laminates having the same sheet arrangement as in (c) are prepared and symmetrically arranged with a 100 mm square 100 μm thick green sheet 75 to be the first constraining layer. It is sectional drawing of a laminated body. After firing these two green laminates at about 1000 ° C., in (d), after removing the first constraining layer, the state of the grooves in each substrate was examined.
[0047]
As a result, in the groove of the substrate corresponding to (c), cracks occurred due to the warpage of the substrate, and the form as the aggregate substrate could not be maintained. On the other hand, no crack was generated in the groove of the substrate corresponding to (d), and the form as the collective substrate was maintained. Thus, it was confirmed that the groove was not cracked even when a deep groove such as a collective substrate was formed, when manufactured by the manufacturing method of the present invention in which warpage was suppressed.
[0048]
【The invention's effect】
As described above, according to the present invention, the blocks having the same amount of warpage generated during firing are stacked, fired, and constrained layer removed by sandwiching the constraining layer and facing each other so that the warping directions are opposite. As a result, a multilayer ceramic substrate having a small warpage can be manufactured.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining a first embodiment of a multilayer ceramic substrate manufacturing method of the present invention.
FIG. 2 is a perspective view for explaining a second embodiment of the method for manufacturing a multilayer ceramic substrate according to the present invention.
FIG. 3 is a perspective view for explaining an application example of the multilayer ceramic substrate manufacturing method of the present invention.
FIG. 4 is a perspective view for explaining an application example of the multilayer ceramic substrate manufacturing method of the present invention.
FIGS. 5A and 5B are a cross-sectional view and a plan view for explaining the contents of an experiment according to the first embodiment of the present invention.
FIGS. 6A and 6B are a cross-sectional view and a plan view for explaining the contents of an experiment according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view for explaining the contents of an experiment using a substrate having a shape shown in an application example of the present invention.
[Explanation of symbols]
11 ceramic green sheet 12 ... (a first constraining layer) constrained green sheet 14 ... first constraining layer 15 ... second constraining layer 16 ... ear 17 ... cavity 18 ... groove 19 ... ceramic layer 20 ... lamination Body 21 first block 22 second block 30 fired laminate 31 multilayer ceramic substrate 32 multilayer ceramic substrate

Claims (5)

A ceramic green sheet, a green sheet preparing step of preparing a constrained green sheet that does not sinter at the sintering temperature of the ceramic green sheet,
A conductor wiring forming step of forming a conductor wiring portion on the ceramic green sheet,
A first block formed of the ceramic green sheet and a second block formed of the ceramic green sheet and generating the same amount of warpage as the first block generates during firing are defined by a warping direction during firing. Are arranged in opposite directions, and the constrained green sheet to be the first constraining layer is arranged between the main surface of the first block and the main surface of the second block to produce a laminate. Laminating process,
A firing step of firing the laminate,
A method for manufacturing a multilayer ceramic substrate, comprising performing a first constraining layer removing step of removing the first constraining layer from a fired laminate. In the laminating step, the ceramic green sheet constituting the first block, the constrained green sheet, and the ceramic green sheet constituting the second block, the lowermost layer when the laminate is formed The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the multilayer ceramic substrate is stacked by being sequentially stacked in ascending order. A second constraining layer forming step of forming a second constraining layer, which is not removed even after firing, on a main surface of the specific ceramic green sheet constituting the first block and the second block. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein: The said laminating process arrange | positions so that the sheet | seat arrangement | sequence of the said 1st block and the said 2nd block may be symmetrical centering on the constrained green sheet which should become the said 1st constrained layer. The method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 3. In the laminating step, the constrained green sheets to be the first constrained layers smaller than the size of the main surface of the laminate are laminated with the ceramic green sheets at both ends or the outer periphery when the laminate is formed. It is characterized by being arranged so that
Further, after the firing step, from the fired laminate, the laminated portion of the ear portion including the ceramic layer located at both ends or the outer peripheral portion of the first constraining layer is subjected to the main surface of the fired laminate. The method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 4, further comprising an ear removing step of cutting away from the direction.

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