JP3631590B2 - Wiring board - Google Patents

Description

【００６５】
表１から明らかなように、試料番号１、２、８は、Ｃｕを主成分とする配線層とガラスセラミック基板との接着強度が弱いものとなり、良品の範囲からはずれる。
【００６６】
試料番号１、２のように、ＳｉＯ_２ の含有量が０．５ｗｔ％未満の場合、ガラスセラミック基板から配線層中に浸透してくるガラス成分との反応が少なくなり、配線層とガラスセラミック基板との接着強度が低下する。尚、試料番号１、２では、抵抗率も大きく実用的ではない。
【００６７】
試料番号８のように、ＳｉＯ_２ の含有量が２．０ｗｔ％を越える場合、Ｃｕ粒子の過焼結が起こるため、配線層とガラスセラミック基板との接着強度が低下する。
【００６８】
試料番号９、１０は、資料番号４のようにＳｉＯ_２ の含有量が特性上最も安定する含有量（０．８ｗｔ％）であっても、配線層とガラスセラミック基板との接着強度が１．６ｋｇ／２ｍｍ角以下と弱く、しかも、ガラスセラミック配線基板の反りがいづれも３０μｍ越えて大きくなる。
【００６９】
試料番号９、１０のように、導電性繊維のうち少なくとも一種の含有量が、０．５ｗｔ％未満の場合、配線層の収縮開始温度を遅らせる効果がなくなるため、ガラスセラミック基板側から浸透するガラス成分が少なくあり、接着強度が低下し、同時にガラスセラミック基板の反り、うねりが増大する。
【００７０】
試料番号２１、２２は配線層とガラスセラミック磁器との接着強度が２ｋｇ／２ｍｍ角以下と弱く、抵抗率も大であるため実用的ではない。
【００７１】
試料番号２１、２２のように、導電性繊維のうち少なくとも一種の含有量が、４０ｗｔ％を越えて添加すると、配線層の焼結の阻害の度合いが大きくなることから、収縮開始温度の遅れが大きくなり、その結果、配線層とガラスセラミック基板との接着強度の低下、配線抵抗の増大という問題が発生する。
【００７２】
また、試料番号２３、２４のように、導電性繊維として、ＳｉＣから炭素（Ｃ）に変えても、良好な結果が得られ、さらに、試料番号２５〜２７のように、Ｃｕ系材料を酸化銅単体、またはＣｕ単体と酸化銅を混合した場合でも、良好な結果が得られる。さらに、試料番号２８〜３０のように、Ｃｕ系材料を酸化銅単体、またはＣｕ単体と酸化銅を混合し、且つ導電性繊維として、炭素（Ｃ）を用いても良好な結果が得られる。
【００７３】
さらに、Ｃｕ系材料を銅合金に変えても、良好な結果が得られることを確認した。
【００７４】
尚、上述の実施例では、基板構造が積層体で説明したが、単状のガラスセラミックシート上に上述のＣｕを主成分とするメタライズペーストを用いて、所定配線パターンを形成し、グリーンシートと所定配線パターンとを一体的に焼結した配線基板でも構わない。
【００７５】
また、基板構造が積層構造であっても、内部配線層２のみを積層体と同時に焼成処理し、表面配線層を既に焼成された積層体に焼き付け処理で形成しても構わない。
【００７６】
【発明の効果】
以上、本発明の配線基板は、Ｃｕを主成分とするメタライズ配線層が、ガラスセラミック材料のガラス成分と反応するためにＳｉＯ_２ とＣｕを主成分とするメタライズ配線層の収縮開始温度を遅らせる導電繊維を含有することから、Ｃｕを主成分とするメタライズ配線層の収縮開始温度をガラスセラミック基板の収縮開始温度に近似させることができ、一体的な焼結が可能となる。
【００７７】
しかも、ガラスセラミックスが液相を生成する温度で、Ｃｕを主成分とするメタライズ配線層組成物もほぼ同時に液相を生成し、両者の収縮も同時に開始されるため、最終的に配線基板の反りやうねり等の変形が極めて小さくすることができる。
【００７８】
配線層の収縮開始温度が遅れることによって、ガラスセラミック材料のガラス成分が配線層側に浸透し、その結果、配線層に含有したＳｉＯ_２ と強固に結合するため、配線層とガラスセラミックからなる基板との界面の接着強度が高くなる。しかも、ＳｉＯの存在、ガラス成分が浸透したとしても、導電性繊維の含有によって、配線層の低抵抗特性を安定的に維持または向上することがてきる。
【図面の簡単な説明】
【図１】本発明の配線基板の一例を示す配線基板の断面図である。
【符号の説明】
１・・・・配線基板
１０・・・積層体
１ａ〜１ｅ・・・ガラスセラミック層
２・・・・メタライズ内部配線層
３・・・・メタライズ表面配線層
４・・・・ビアホール導体
５・・・・電子部品[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wiring board in which a metallized wiring layer mainly composed of Cu, which is sintered integrally with the substrate, is formed on the surface or inside of a single plate or laminated substrate made of glass ceramics.
[0002]
[Prior art]
A wiring board having an internal wiring layer that is sintered integrally with the substrate and a surface wiring layer on a substrate made of glass ceramics becomes an unfired substrate that becomes a glass ceramic substrate and an internal wiring layer or a surface wiring layer. The wiring pattern is formed by integrally sintering at 800 to 1000 ° C. and is called a low-temperature fired wiring board.
[0003]
This low-temperature fired wiring board can be fired at a relatively low temperature of 800 to 1000 ° C., and a low resistance material such as Au, Ag, or Cu can be used as a material constituting the wiring layer. It is used for a package for housing semiconductor elements to be mounted, various circuit boards having circuit wiring conductors, mobile phones, personal handyphone systems, and multilayer wiring boards for high frequency for various satellite communications.
[0004]
In recent years, high-frequency circuit compatibility, high density, and high speed have been demanded for wiring boards. Low-temperature fired wiring that has a lower dielectric constant than alumina-based ceramic materials and can reduce the resistance of the wiring layer. Substrates are drawing more attention.
[0005]
Of the low resistance wiring layer materials used for low-temperature fired wiring substrates, Au-based materials, Ag-based materials, and Cu-based materials, Au-based materials are very expensive and disadvantageous in terms of cost. Since Ag diffuses and causes migration and the like, there are limitations on the use and structure of the wiring board.
[0006]
On the other hand, the Cu-based material is a material that can sufficiently meet the demands for higher density of the wiring board and higher frequency of the circuit in the wiring board, although the firing process needs to be performed in a reducing atmosphere. .
[0007]
A wiring board in which a metallized wiring layer containing Cu as a main component is formed on the surface and inside of a substrate made of glass ceramic is generally (1) a slurry prepared by adding a solvent to a glass ceramic raw material powder and an organic binder. Formed into a sheet by a blade method, etc. (2) The obtained glass ceramic green sheet is punched with through holes, and the through holes are filled with a metallized paste containing Cu as a main component. A predetermined wiring pattern to be a wiring layer is printed and formed by a known screen printing method or the like using a metallized paste containing Cu as a main component, and (3) a glass ceramic in which a conductor filled in the wiring pattern or through hole is formed. A plurality of green sheets are pressure laminated, (4) the resulting laminate is heated to burn off the organic binder, (5) It has been produced by sintering at Ide 800 to 1000 ° C.. In addition, the wiring used as a surface wiring layer was printed and formed in the process of (2), and was printed and formed on the unfired laminated body obtained at the process of (3). Thereafter, various electronic components such as ICs were mounted on the surface wiring layer of the substrate as necessary.
[0008]
The metallized paste, which is fired simultaneously with the insulating substrate at a relatively low temperature of 800 to 1000 ° C. and becomes a metallized wiring layer mainly composed of Cu, is a conductive material of a Cu-based material (Cu simple substance Cu oxide, Cu alloy). The material, a glass component for approximating the sintering behavior of the metallized paste to glass ceramic, and an organic vehicle (organic binder, organic solvent) were uniformly mixed. As a glass component for approximating the sintering behavior of the glass ceramic material, Bi ₂ O ₃ And MoO ₃ , Cr ₂ O ₃ Etc. were used.
[0009]
[Problems to be solved by the invention]
However, conventionally, the sintering start temperature of the glass ceramic material is generally 800 to 1000 ° C., for example, around 850 ° C., and the sintering start temperature of the metallized wiring layer mainly composed of Cu is 700 to 800 ° C., for example 750 ° C. Before and after. Therefore, due to the difference in the sintering start temperature, a shrinkage occurs in the shrinkage during the firing process, and further, due to the difference in the sintering end temperature, the metallized wiring layer mainly composed of Cu is densified first and the glass ceramic material is shrunk. It will be suppressed. As a result, the fired wiring board has a problem that deformation such as a large warp or undulation exceeding Rum of 30 μm, for example, occurs.
[0010]
In order to prevent the occurrence of deformation such as large warping and waviness, the glass component of the metallized paste containing Cu as a main component is adjusted so that the sintering behavior of the metallized wiring pattern is changed to the sintering behavior of the glass ceramic material. It is possible to approximate. However, this impairs the low resistance characteristics of the metallized wiring layer mainly composed of Cu, and it is very difficult to adjust the glass component.
[0011]
Further, when the metallized wiring pattern containing Cu as a main component is over-sintered, Cu particles become dense and prevent strong bonding with the glass component of the glass ceramic material. Deteriorate. For example, it peels off with a tensile load of less than 2 kg. With such a weak adhesive strength, there is a problem in that various chip parts are mounted on the surface wiring layer of the glass ceramic substrate or a problem such as no need for bonding occurs when mounted on a mother board or the like.
[0012]
As a result of diligent research, the present inventors have made SiO into a metallized wiring material mainly composed of Cu. ₂ Can be firmly bonded to the glass ceramic insulating substrate, delay the sintering start temperature of the metallized wiring layer mainly composed of Cu, and approximate the sintering behavior to the sintering behavior of the glass ceramic substrate. It has been found that deformations such as substrate warpage and swell can be reduced.
[0013]
The present invention is based on the above-described knowledge, and the object thereof is to effectively prevent warping and undulation of the substrate even when the Cu metallized wiring layer and the insulating substrate made of glass ceramic are simultaneously fired. An object of the present invention is to provide a wiring board having high adhesive strength at the interface between the metallized wiring layer and the glass ceramic material, and not impairing the low resistance characteristic of the Cu metallized wiring layer and the low dielectric constant characteristic of the glass ceramic material. .
[0014]
[Means for Solving the Problems]
According to the present invention, Cu as the main component, 0.5-2.0wt% SiO ₂ , as well as 0.5-40 wt% conductive fiber contains A wiring board having a metallized wiring layer on the surface and / or inside of a glass ceramic substrate. The conductive fiber is at least one or more of fibrous bodies of carbon (C) and SiC.
[0015]
The conductive fibers described above have a diameter of 0.1 to 5 μm and a length of 1 to 50 μm.
[0016]
[Action]
According to the present invention, the metallized wiring layer containing Cu as a main component contains conductive fibers. That is, when a wiring pattern to be a metallized wiring layer is printed and formed on a glass ceramic green sheet by a known screen printing method or the like using a metallized paste containing Cu as a main component and containing conductive fibers, the conductive fibers are contained in the wiring pattern. Oriented and dispersed substantially horizontally. Even if the Cu particles of the wiring pattern try to aggregate due to the subsequent sintering, the conductive fibers inhibit the aggregation of the Cu particles and delay the shrinkage start temperature of the wiring pattern. As a result, the metallized wiring pattern and the sintering behavior of the glass ceramic material are approximated, and the occurrence of warpage, undulation, etc. is reduced on the surface of the wiring board.
[0017]
Further, the glass component of the glass ceramic material easily penetrates into the gaps between the Cu particles of the wiring pattern. At this time, SiO contained in the wiring pattern ₂ As a result, the adhesive strength between the sintered metallized wiring layer and the glass-ceramic substrate is improved.
[0018]
In addition, although the glass component is contained in the metallized wiring layer containing Cu as a main component and the glass component penetrates from the glass ceramic substrate side, the resistivity of the metallized wiring layer tends to be deteriorated. The above-mentioned conductive fibers are included to prevent the resistivity from deteriorating, and conversely, the resistance is reduced.
[0019]
In the present invention, a Cu-based material used for a metallized paste containing Cu as a main component is Cu alone, naturally oxidized or intentionally oxidized copper oxide (CuO, CuO). ₂ ), A copper alloy, and a mixture thereof, and for each particle, it is preferable to use a spherical powder having an average particle diameter of 0.5 to 15 μm, preferably 3 to 5 μm. This is to delay the sintering start temperature of the metallized wiring pattern containing Cu as a main component.
[0020]
In addition, SiO in the metallized wiring layer containing Cu as a main component ₂ When the content of the metal is less than 0.5 wt%, when the wiring pattern is fired, there is less reaction with the glass component penetrating from the glass ceramic substrate into the metallized wiring pattern, and as a result, the fired metallized wiring The adhesive strength between the layer and the glass ceramic substrate is less than 2.0 kg / 2 mm square.
[0021]
On the other hand, when the content exceeds 2.0 wt%, Cu-based particles are oversintered. As a result, the adhesive strength between the metallized wiring layer and the glass ceramic substrate is lowered. At the same time, the resistance of the wiring layer tends to increase.
[0022]
Furthermore, when the content of at least one of the conductive fibers is less than 0.5 wt%, the effect of delaying the sintering start temperature of the wiring pattern to be the metallized wiring layer is not sufficient, and as a result, the wiring board warps. The swell increases.
[0023]
On the other hand, if added over 40 wt%, the degree of inhibition of the sintering of the metallized wiring pattern increases, so the delay in the sintering start temperature increases, and as a result, the adhesion between the metalized wiring layer and the glass ceramic substrate is increased. There arises a problem that the strength decreases and the wiring resistance increases.
[0024]
Therefore, the SiO ₂ The content is preferably 0.5 to 2.0 wt%, and the conductive fiber is preferably 0.5 to 40 wt%.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a wiring board of the present invention will be described with reference to the drawings.
[0026]
In the description, the structure of the wiring board will be described using a multilayer wiring board composed of a plurality of glass-ceramic layers.
[0027]
In the figure, 1 is a wiring board, 10 is a laminate, and 5 is various electronic components such as an IC. The laminated body 10 is formed by laminating glass ceramic layers 1a to 1e and a metallized internal wiring layer (hereinafter, simply referred to as an internal wiring layer 2) mainly composed of Cu disposed between the glass ceramic layers 1a to 1e. In addition, a via hole conductor 4 formed so as to penetrate the thickness direction of each of the glass ceramic layers 1a to 1e is formed, and a metallized surface wiring mainly composed of Cu formed on the surface of the laminate 10 is formed. A layer (hereinafter simply referred to as a surface wiring layer 3) is formed. Thereby, a circuit network for achieving a predetermined circuit in the laminate 10 is formed.
[0028]
The glass ceramic layers 1a to 1e are made of a glass ceramic material that can be fired at, for example, 850 to 1000 ° C. Specifically, the glass component of the glass ceramic material is a glass frit containing a plurality of metal oxides, and is subjected to a firing treatment to obtain cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, petalite. And at least one kind of crystals of substituted derivatives thereof are precipitated. For example, SiO ₂ , Li ₂ O, Al ₂ O ₃ , P ₂ O ₅ , K ₂ O, ZnO, Na ₂ O lithium silicate glass or SiO ₂ , Al ₂ O ₃ , MgO, ZnO, B ₂ O ₃ Examples thereof include borosilicate glass containing PbO. Examples of the ceramic component of the glass ceramic material include cristobalite, quartz, corundum (α alumina), mullite, and cordierite. The composition ratio of the glass component and the ceramic component is 30 to 70 wt% for the glass component and 70 wt% to 30 wt% for the ceramic component, and the thickness of the glass ceramic layers 1 a to 1 e is about 100 to 300 μm, for example.
[0029]
The internal wiring layer 2 is made of Cu-based (Cu simple substance, Cu oxide, alloys thereof), conductive fibers having heat resistance such as C, SiC, SiO ₂ It consists of a glass component, and is formed in a predetermined pattern with a thickness of 8 to 25 μm between the glass ceramic layers 1a to 1e.
[0030]
The internal wiring layer 2 is used as a ground plate for generating a capacitance component between other internal wiring layers 2 as a wiring for forming a predetermined circuit network and a line for forming an inductance component.
[0031]
Specifically, the internal wiring layer 2 is formed by printing a metallized paste containing the above-described solid component on a glass ceramic green sheet made of glass ceramic layers 1a to 1e in a predetermined pattern, and simultaneously with the glass ceramic layers 1a to 1e in a reducing atmosphere. Sintered and formed.
[0032]
The via-hole conductor 4 is formed by filling a conductor mainly composed of Cu in a through-hole having a diameter of 80 to 200 μm formed so as to penetrate the glass ceramic layers 1a to 1e. The via-hole conductor 4 connects the predetermined internal wiring layers 2 and 2, and connects the predetermined surface wiring layer 3 and the predetermined internal wiring layer 2.
[0033]
Specifically, the via-hole conductor 4 has through holes formed in the glass ceramic green sheets made of the glass ceramic layers 1a to 1e, and the metallized paste similar to the above is printed and filled in the through holes and baked in a reducing atmosphere. It is formed by tying.
[0034]
The surface wiring layer 3 is made of Cu-based (Cu simple substance, Cu oxide, alloys thereof), carbon (C), conductive fibers having heat resistance such as SiC, SiO ₂ It consists of a glass component and is formed in a predetermined pattern on the surface of the laminate 10 with a thickness of 8 to 25 μm. The surface wiring layer 3 is used as wiring for forming a predetermined circuit network, as a pad for mounting various electronic components 6 such as an IC chip, as a conductor film for shielding, and as a terminal electrode connected to an external circuit. Used.
[0035]
Specifically, the surface wiring layer 3 is formed by printing a metallized paste containing the above-described solid component in a predetermined pattern on the surface of the green sheet laminate 10 that becomes the glass ceramic layers 1a and 1e, and the glass ceramic layer 1a. It is formed by sintering in a reducing atmosphere simultaneously with ˜1e.
[0036]
Various electronic components 5 such as an IC chip are mounted on the surface wiring layer 3 of the laminate 10 as necessary. Specifically, the various electronic components 5 are joined to the surface wiring layer 3 via solder, conductive resin adhesive, or the like. Although not shown, a thick film resistor film such as tantalum silicide or molybdenum silicide, a wiring protective film, or the like may be formed on the surface of the stacked body 10 as necessary.
[0037]
The characteristic feature of the present invention is that an internal wiring layer 2 and / or a surface wiring layer 3 that are sintered simultaneously with the laminated body 10 are formed on the laminated body 10 made of a glass ceramic material. The internal wiring layer 2 and the surface wiring layer 3 are mainly composed of a Cu-based material, and SiO 2 ₂ Including conductive fibers.
[0038]
In addition, SiO ₂ Is a solid component constituting the wiring layers 2 and 3 (Cu-based, SiO 2 ₂ In the solid component, the conductive fiber is contained in a proportion of 0.5 to 40 wt%.
[0039]
As a result, the wiring pattern to be the internal wiring layer 2 and the surface wiring layer 3 and the glass ceramic material to be the glass ceramic layers 1a to 1e can be fired at the same time. Warpage and undulation can be effectively prevented.
[0040]
Further, the adhesive strength between the sintered internal wiring layer 2 and the surface wiring layer 3 and the glass ceramic layers 1a to 1e is strengthened, and the internal wiring layer 2 and the surface wiring layer 3 mainly composed of Cu are low. A wiring substrate 10 that does not deteriorate resistance characteristics is obtained.
[0041]
As described above, the internal wiring layer 2 is formed of a Cu-based material, conductive fiber, SiO2 on the glass ceramic grease sheet to be the glass ceramic layers 1a to 1e. ₂ A wiring pattern to be the internal wiring layer 2 is formed using a metallized paste containing Cu as a main component, and a plurality of such glass ceramic grease sheets are laminated, and then formed by firing treatment.
[0042]
As described above, the surface wiring layer 3 has a Cu-based material, conductive fibers, SiO 2 on the surface to be the surface of the laminated body 10 of the glass ceramic grease sheets to be the glass ceramic layers 1a and 1e. ₂ It is formed by printing a metallized paste containing Cu as a main component, and is formed in the same manner as the internal wiring layer 2 described above. In addition, regarding this surface wiring layer 3, the above-mentioned metallized paste is printed on the surface of the unfired laminate formed by laminating green sheets to be the glass ceramic layers 1a to 1e to form the surface wiring layer 3. When the wiring pattern is formed and the unfired laminate is fired, the wiring pattern may be fired at the same time.
[0043]
Further, the metallized paste mainly composed of Cu for forming the internal wiring layer 2 and the surface wiring layer 3 described above is a Cu-based material, SiO, which is a fixed component. ₂ It is formed by intimately mixing a conductive fiber, an organic bander made of an acrylic resin, and the like, and an organic solvent such as toluene, isopropyl alcohol, and asenton.
[0044]
Cu-based materials constituting the solid component include Cu alone, Cu alloy, CuO and Cu ₂ A simple substance of Cu oxide such as O or a mixture thereof is used. Note that copper oxide is substantially reduced by firing in a reducing atmosphere.
[0045]
In addition, SiO ₂ Is used in the range of 0.5 to 2.0 wt% in the solid component.
[0046]
In addition, the conductive fiber is a conductive material having a high melting point such as carbon (C) or SiC having a diameter of 0.1 to 5 μm and a length of 1 to 50 μm. It is used in the range of 40 wt%. The diameter and length of the conductive fibers are set to values that can easily pass through the openings of the screen mesh and do not protrude from the pattern dimensions when printing and forming the metallized wiring pattern.
[0047]
The organic binder is dispersed at a ratio of 0.5 to 5.0 wt% with respect to the solid component, and the organic solvent is mixed at a ratio of 5 to 100 wt% with respect to the solid component and the organic binder.
[0048]
The above-mentioned metallized paste is formed by printing a wiring pattern to be the internal wiring layer 2 and the surface wiring layer 3 on the glass ceramic green, the organic solvent is volatilized by a drying process, and further, an organic binder, Organic components such as organic solvents are lost.
[0049]
The internal wiring layer 2 and the surface wiring layer 3 of the present invention contain conductive fibers in the range of 0.5 to 40 wt%. In order to form the internal wiring layer 2 and the surface wiring layer 3, the conductive fibers contained therein are printed on the glass ceramic green sheets to be the glass ceramic layers 1a to 1e in a predetermined shape by a screen printing method. When the wiring pattern is formed by drying, the wiring pattern is oriented and dispersed substantially in the horizontal direction. In this state, when the baking treatment is performed together with the glass ceramic green sheet, Cu particles of the Cu-based material of the wiring pattern tend to aggregate. However, the presence of the conductive fibers inhibits the aggregation of Cu particles, and as a result, even if the glass ceramic layers 1a to 1e start to shrink, the metallized wiring pattern mainly composed of Cu has some followability. Appears, warping the surface of the fired laminated body 10, and the occurrence of waviness or the like can be effectively suppressed.
[0050]
That is, since the glass ceramic generates a liquid phase almost simultaneously at the temperature at which the glass ceramic generates a liquid phase, the shrinkage of both starts simultaneously, so that finally the deformation of the wiring board, such as warping and waviness, is extremely small. Is something that can be done.
[0051]
Further, the internal wiring layer 2 and the surface wiring layer 3 have a SiO content of 0.5 to 2.0 wt%. ₂ Contains. As described above, since the shrinkage start temperature of the wiring pattern is delayed, the glass component contained in the glass ceramic material easily penetrates into the wiring pattern side, and SiO, which is a homogeneous glass component contained in the wiring pattern side. ₂ And firmly bond with each other. As a result, the adhesive strength between the fired wiring layers 2 and 3 and the glass ceramic layers 1a to 1e is greatly improved.
[0052]
Moreover, since the above-mentioned conductive fiber contains in the internal wiring layer 2 and the surface wiring layer 3 which have Cu as a main component, SiO which worsens resistivity. ₂ Even if there is a glass component penetrating from the glass ceramic material, the resistivity is prevented from deteriorating, and conversely, the resistance reduction is improved.
[0053]
In the above description, warping and undulation occurring on the surface of the fired laminated body 10 are suppressed by the presence of the conductive fibers because the shrinkage start temperature of the metallized wiring pattern mainly composed of Cu is reduced. This is achieved by delaying, but the occurrence of warpage and undulation on the surface of the wiring board 1 is also reduced when the conductive fibers are horizontally oriented in the printed wiring pattern. That is, the sintering shrinkage of the laminate 10 is mainly caused by the stress in the thickness direction, but this stress is caused by conductive fibers made of carbon (C) or SiC having a high melting point being horizontally oriented in the wiring pattern. Work to shut off. Moreover, since the conductive fiber maintains the original shape firmly, it also works to suppress horizontal shrinkage.
[0054]
【Example】
In order to investigate the effect of the present invention, the inventors changed the composition of the metallized paste mainly composed of Cu, and the effects of the wiring layers 2 and 3 fired simultaneously with the glass ceramic layers 1a to 1e. Examined.
[0055]
First, as a material of the glass component of the glass ceramic material, SiO ₂ , Li ₂ O, Al ₂ O ₃ , P ₂ O ₅ , K ₂ O, ZnO, Na ₂ O lithium silicate glass powder as an inorganic filler, SiO ₂ A slurry was prepared by preparing powder, acrylic resin as a binder, DBP (dibutyl phthalate) as a plasticizer, toluene and isopropyl alcohol as organic solvents, and a green sheet having a thickness of 500 μm was prepared by a doctor blade method.
[0056]
In addition, as a metallized paste containing Cu as a main component, a simple substance of Cu having an average particle diameter of 5 μm is used, and the entire solid component is made of SiO. ₂ The conductive fibers were weighed in the proportions shown in Table 1, and an acrylic resin as an organic binder and DBP as a solvent were added and kneaded thereto to prepare a metallized paste containing Cu as a main component.
[0057]
The amount of the organic binder was 2.0 wt% with respect to the solid component, and the solvent was added at a ratio of 75 wt% with respect to the solid component and the organic binder.
[0058]
As a sample pattern for evaluating the wiring resistance with the above-mentioned metallized paste containing Cu as a main component on one main surface of the glass ceramic green sheet, the width after firing is 0.2 mm, the length is 20 mm, and the thickness is about 15 μm. A wiring pattern was formed, and three such glass ceramic green sheets were pressure laminated. At the same time, on one main surface of the glass ceramic green sheet, as a sample pattern for evaluating the printing adhesive strength and warp with the above-mentioned metallized paste containing Cu as a main component, the wiring is 2 mm in length and width and about 15 μm in thickness after firing A pattern was formed, and three such glass ceramic green sheets were pressure laminated.
[0059]
Next, the laminate on which the unfired sample pattern was formed was degreased by holding it at a temperature of 700 ° C. for 3 hours in a nitrogen atmosphere containing water vapor in order to decompose and remove organic components such as an organic binder. Thereafter, the atmosphere in the furnace is switched to dry nitrogen, heated to 900 ° C. and held for 1 hour, and the wiring board 1 in which the wiring layers 2 and 3 containing Cu as a main component are formed inside and on the surface of the laminate 10. A sample was prepared.
[0060]
First, Ni plating with a thickness of 2.0 μm is performed on a metallized wiring pattern of 2 mm square Cu as a main component of the wiring substrate 1 to be evaluated for printing adhesive strength and warpage, and Au plating with a thickness of 0.1 μm is formed thereon. After soldering, the Cu-based lead wire on the plating coating layer is soldered in parallel to the surface of the wiring layer, the lead wire is bent in a direction perpendicular to the surface of the wiring layer, and the lead wire is pulled at 10 mm / min. The load when the lead wire was peeled off at a speed in the vertical direction was evaluated as the adhesive strength of the wiring layer. In addition, as a judgment of quality, the case where the load when the lead wire peeled exceeded 2 kg / 2 mm square was regarded as a non-defective product.
[0061]
The warpage of the glass ceramic wiring board is measured by measuring the surface state of the surface of the glass ceramic board immediately below the 2 mm square wiring layer, including the wiring layer portion, across the wiring layer, having a length of 7 mm. Was evaluated as the amount of warpage. In addition, as a judgment of quality, the thing with Rmax of 30 micrometers or less was made into the quality goods.
[0062]
Next, using a wiring board for evaluating wiring resistance, the resistance of a wiring layer having a width of 0.2 mm and a length of 20 mm was measured with a tester, and the cross section of the wiring layer was measured with a scanning electron microscope (SEM). Was measured using a 40 × microscope, and the resistivity was calculated from the obtained area and length. In addition, as a judgment of quality, a resistivity of 10.0 μΩ · cm or less was regarded as a non-defective product.
[0063]
The results of Table 1 are shown in Table 1.
[0064]
[Table 1]

[0065]
As is apparent from Table 1, Sample Nos. 1, 2, and 8 have weak adhesive strength between the wiring layer mainly composed of Cu and the glass ceramic substrate, and are out of the non-defective range.
[0066]
Like sample numbers 1 and 2, SiO ₂ When the content of is less than 0.5 wt%, the reaction with the glass component penetrating from the glass ceramic substrate into the wiring layer is reduced, and the adhesive strength between the wiring layer and the glass ceramic substrate is lowered. In Sample Nos. 1 and 2, the resistivity is large and not practical.
[0067]
Like sample number 8, SiO ₂ When the content of C exceeds 2.0 wt%, Cu particles are oversintered, so that the adhesive strength between the wiring layer and the glass ceramic substrate is lowered.
[0068]
Sample Nos. 9 and 10 are SiO ₂ Even if the content of S is the most stable content (0.8 wt%), the adhesive strength between the wiring layer and the glass ceramic substrate is as weak as 1.6 kg / 2 mm square or less, and the glass ceramic wiring substrate Any warpage increases beyond 30 μm.
[0069]
When the content of at least one of the conductive fibers is less than 0.5 wt% as in Sample Nos. 9 and 10, the effect of delaying the shrinkage start temperature of the wiring layer is lost, so that the glass that permeates from the glass ceramic substrate side There are few components, adhesive strength falls, and the curvature of a glass ceramic substrate and a wave | undulation increase simultaneously.
[0070]
Sample Nos. 21 and 22 are not practical because the adhesive strength between the wiring layer and the glass ceramic porcelain is as weak as 2 kg / 2 mm square or less and the resistivity is large.
[0071]
Like Sample Nos. 21 and 22, when the content of at least one of the conductive fibers exceeds 40 wt%, the degree of inhibition of sintering of the wiring layer increases, and therefore the shrinkage start temperature is delayed. As a result, there arises a problem that the adhesive strength between the wiring layer and the glass ceramic substrate is lowered and the wiring resistance is increased.
[0072]
Moreover, even if it changes from SiC to carbon (C) as a conductive fiber like the sample numbers 23 and 24, a favorable result is obtained, and also Cu-type material is oxidized like the sample numbers 25-27. Even when copper alone or Cu alone and copper oxide are mixed, good results can be obtained. Furthermore, as in sample numbers 28 to 30, good results can be obtained even when Cu (C) is used as the conductive fiber by mixing Cu-based material with copper oxide alone or with Cu alone and copper oxide.
[0073]
Furthermore, it was confirmed that good results were obtained even when the Cu-based material was changed to a copper alloy.
[0074]
In the above-described embodiment, the substrate structure has been described as a laminated body. However, a predetermined wiring pattern is formed on a single glass ceramic sheet using the above-described metallized paste containing Cu as a main component, and a green sheet and A wiring board obtained by integrally sintering a predetermined wiring pattern may be used.
[0075]
Even if the substrate structure is a laminated structure, only the internal wiring layer 2 may be fired at the same time as the laminated body, and the surface wiring layer may be formed on the already fired laminated body by baking.
[0076]
【The invention's effect】
As described above, the wiring board of the present invention is made of SiO because the metallized wiring layer mainly composed of Cu reacts with the glass component of the glass ceramic material. ₂ And the conductive fiber that delays the shrinkage start temperature of the metallized wiring layer mainly composed of Cu, the shrinkage start temperature of the metallized wiring layer mainly composed of Cu can be approximated to the shrinkage start temperature of the glass ceramic substrate. And integrated sintering is possible.
[0077]
In addition, at the temperature at which the glass ceramics generates a liquid phase, the metallized wiring layer composition containing Cu as a main component also generates a liquid phase almost simultaneously, and the shrinkage of both starts simultaneously. Deformation such as waviness can be made extremely small.
[0078]
As the shrinkage start temperature of the wiring layer is delayed, the glass component of the glass ceramic material penetrates into the wiring layer side, and as a result, the SiO contained in the wiring layer ₂ Therefore, the adhesive strength at the interface between the wiring layer and the substrate made of glass ceramic is increased. Moreover, even if the presence of SiO and the glass component penetrate, the low resistance characteristics of the wiring layer can be stably maintained or improved by the inclusion of the conductive fibers.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a wiring board showing an example of a wiring board according to the present invention.
[Explanation of symbols]
1 ... Wiring board
10 ... Laminated body
1a to 1e ... Glass ceramic layer
2 ... Metalized internal wiring layer
3 ... Metallized surface wiring layer
4. Via hole conductor
5 ... Electronic parts

Claims (2)

A metallized wiring layer containing Cu as a main component and containing 0.5 to 2.0 wt% of SiO ₂ and 0.5 to 40 wt% of conductive fibers is provided on the surface and / or inside of a substrate made of glass ceramic. Wiring board. The wiring board according to claim 1, wherein the conductive fiber is at least one or more of carbon (C) and SiC.

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