JP2004228533A - Ceramic package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro and ultrathin ceramic package which achieves a simultaneous firing with a metallized layer and is hardly broken down even though the lid body is directly seam-welded to a metal connecting layer of an insulating substrate. <P>SOLUTION: The insulating substrate 1 consisting of a substrate bottom portion 1a for surface-mounting an electric element and a substrate bank portion 1b integrally provided at the periphery of the substrate bottom portion 1a, a conductor layer 2 provided in the inner portion and/or on the surface of the insulating substrate 1, and a metal connecting layer 3 provided for connecting the lid body to at least a part of the substrate bank portion 1b are provided. The insulating substrate 1 consists of an alumina sintered body including 4 mass % or more sintering agent. The metal connecting layer 3 is constituted of the metallized layer 3a and a plated layer 3b with a lower electric resistance than the metallized layer 3a. Conductive resistance per unit area of the metal connecting layer 3 is 1.0 to 1.3 Ω/cm2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００８０】
【表２】

【００８１】
本発明の試料Ｎｏ．２、５、７、９及び１１〜３１は、金属接続層の導通抵抗が１．０〜１．３Ω／ｃｍ^２の範囲であり、接合テスト及び封止テストでも異常は見られなかった。
【００８２】
一方、焼結助剤量（主成分、第２成分、第３成分及び第４成分の合計）が４質量％に満たない本発明の範囲外の試料Ｎｏ．１は、接合テストにおいてメタライズがセラミックスより剥離し、十分な封止をすることができなかった。
【００８３】
また、金属接合層の単位面積当たりの導通抵抗が１．０Ω／ｃｍ^２より低い本発明の範囲外の試料Ｎｏ．３及び１０は封止テストにおいてロウ流れ不足による封止不良が発生した。
【００８４】
さらに、メッキ層を含むメタライズ層の面積当たりの導通抵抗が１．３Ω／ｃｍ^２より高い本発明の範囲外の試料Ｎｏ．４、６及び８は接合テストにおいて、絶縁基板の底部にクラックが観察された。
【００８５】
【発明の効果】
本発明は、金属接合層の単位面積当たりの導通抵抗を制御することによって、同時焼成が可能で、蓋体を直接パッケージにシーム溶接しても破壊しにくいセラミックパッケージを安価に得ることができ、その結果、蓋体の接合に関与する基板堤部の幅が０．１〜０．４ｍｍ、電子素子が実装される基板低部の厚みが０．１〜０．３ｍｍ、パッケージの高さが０．３〜０．６ｍｍであるセラミックパッケージに好適に適応できる。
【００８６】
特に、アルミナ粉末の粉末平均粒径、昇温速度及び冷却速度を制御することによって、３点曲げ強度が５００ＭＰａ以上、ヤング率が３２０ＧＰａ以下、熱伝導率が１５Ｗ／ｍＫ以上、メタライズ強度を４９Ｎ以上とすることができ、さらに接合信頼性を向上することができる。
【図面の簡単な説明】
【図１】本発明のセラミックパッケージの一例を示す概略断面図である。
【図２】内部に電気素子を実装し、蓋体を接合した状態の本発明のセラミックパッケージの概略断面図である。
【符号の説明】
１、１１・・・絶縁基板
１ａ、１１ａ・・・基板底部
１ｂ、１１ｂ・・・基板堤部
２・・・導体層
２ａ、１２ａ・・・表面導体層
２ｂ、１２ｂ・・・裏面導体層
２ｃ、１２ｃ・・・内部導体層
３・・・金属接合層
３ａ、１３ａ・・・メタライズ層
３ｂ、１３ｂ・・・メッキ層
１４・・・電気素子
１４ａ・・・電子部品
１４ｂ・・・半導体素子
１５ａ・・・導電性接着剤
１５ｂ・・・ワイヤボンディング
１６・・・ロウ材
１８・・・蓋体
Ｄ・・・基板底部の厚み
ｄ・・・基板堤部の幅
Ｔ・・・パッケージ高さ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a ceramic package in which an electronic element and / or a semiconductor element is mounted and hermetically sealed by a lid such as a lid, particularly, the height is 0.6 mm or less, and the bank width is 0.4 mm or less. The present invention relates to an ultra-small and ultra-thin ceramic package having a bottom thickness of 0.3 mm or less.
[0002]
[Prior art]
2. Description of the Related Art In recent years, along with the high integration of semiconductor elements and the miniaturization of electronic components, various electronic devices have been miniaturized and enhanced in function. Along with this, it is required to reduce the size of a ceramic package that accommodates an electric element or mounts a passive component at the same time as a semiconductor element. The package has been commercialized.
[0003]
In order to reduce the height, a metal bonding layer formed by laminating a metallized layer and a metal film is formed on the bank instead of the metal ring except for the metal ring of the sealing portion, and the brazing material layer is formed. It has been proposed to reduce the height by performing seam welding via a wire. (For example, see Patent Document 1).
[0004]
In addition, in order to manufacture at low cost, there is a demand for an insulating substrate capable of forming a metallization for joining a lid by simultaneous firing. For example, it has been proposed that metallization be performed at low cost by simultaneous firing by adding alumina with a purity of 96% or less by adding a sintering aid (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP 2001-196485 A
[Patent Document 2]
JP-A-2001-277662
[0006]
[Problems to be solved by the invention]
However, in the ceramic package described in Patent Literature 1, the lid is directly seam-welded to the metal joining layer formed on the bank of the insulating substrate. There is a problem that cracks occur in the insulating substrate.
[0007]
On the other hand, although the alumina sintered body using the ceramic package described in Patent Document 2 can be manufactured at a low cost by metallization, the flexural strength is as low as 400 MPa or less. When the lid and the package are joined for hermetic sealing, there is a problem that the insulating substrate is easily broken.
[0008]
Accordingly, an object of the present invention is to provide an ultra-small and ultra-thin ceramic package that can be simultaneously fired with a metallized layer and is not easily broken even when the lid is directly seam-welded to the metal bonding layer of the insulating substrate. And
[0009]
[Means for Solving the Problems]
In the present invention, since the electric resistance of the conventional metal bonding layer greatly varies depending on the portion, it is necessary to completely melt and join the brazing material with a large current to secure confidentiality. Based on the knowledge that stress occurs and cracks are generated, by controlling conduction resistance per unit area of the metal bonding layer, excessive heating is prevented and cracks are reduced. It is possible to realize an inexpensive ultra-thin and ultra-small ceramic package that is hardly broken even by direct seam welding to the package, can be co-fired, and is inexpensive. In particular, by controlling the average particle size, heating rate, and cooling rate of the alumina raw material powder, the three-point bending strength is not less than 500 MPa, the Young's modulus is not more than 320 GPa, and the thermal conductivity is included even when the sintering aid is not less than 4 mass%. Alumina with a rate of 15 W / mK or more was realized, and a ceramic package with high bonding reliability was realized.
[0010]
That is, the ceramic package of the present invention comprises an insulating substrate including a substrate bottom for mounting an electric element on a surface thereof and a substrate bank integrally provided on the outer periphery of the substrate bottom, and the inside and / or the surface of the insulating substrate. And a metal bonding layer provided for bonding a lid to at least a part of the substrate bank, wherein the insulating substrate has a sintering aid of 4% by mass or more. Wherein the metal bonding layer is composed of a metallized layer and a plating layer having a lower electric resistance than the metallized layer, and a conduction resistance per unit area of the metal bonding layer is 1.0. ~ 1.3Ω / cm ² It is characterized by being.
[0011]
In particular, it is preferable that the width of the substrate bank is 0.1 to 0.4 mm, the thickness of the substrate bottom is 0.1 to 0.3 mm, and the package height is 0.3 to 0.6 mm. By setting such dimensions, thermal stress destruction of the insulating substrate can be more effectively prevented, and the volume of the package can be further reduced.
[0012]
Further, the plating layer is preferably made of Ni and / or Au. Thereby, the adhesion is high, and the resistance of the metal bonding layer can be reduced.
[0013]
Further, it is preferable that the thickness of the plating layer is 8 to 25 μm. Thereby, it is easy to stabilize the heat generated by the main current flowing through the plating layer, and the uniformity of the generated heat can be improved.
[0014]
Furthermore, it is preferable that the adhesive strength of the metallized layer to the substrate bank is 49 N or more. Thereby, peeling that occurs between the ring-shaped metallization layer and the insulating substrate when the lid and the package are joined can be effectively suppressed, and higher reliability can be obtained.
[0015]
The alumina sintered body contains Mn at a ratio of 2 to 8% by mass in terms of oxide and Si at a ratio of 1 to 6% by mass in terms of oxide. ₂ O ₃ MnAl at the grain boundaries of the main crystal phase ₂ O ₄ Preferably, it contains crystals. This makes it easy to increase the strength to 500 MPa or more.
[0016]
The alumina sintered body preferably has a strength of 500 MPa or more, a Young's modulus of 320 GPa or less, and a thermal conductivity of 15 W / mK or more. Thus, even if stress is generated due to a difference in thermal expansion, the stress can be relieved by rapid heat dissipation and deformation, and destruction can be effectively prevented.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described with reference to the drawings.
[0018]
As shown in FIG. 1, for example, the ceramic package of the present invention includes an insulating substrate 1 having a substrate bottom 1a and a substrate bank 1b, a conductor layer 2 provided on the substrate bottom 1a, and a substrate bank 1b. And a metal bonding layer 3 formed on the substrate.
[0019]
The insulating substrate 1 is provided with a substrate bank 1b integrally provided on the outer periphery of a substrate bottom 1a. The substrate bottom 1a has an electric element mounted thereon, and the substrate bank 1b is joined with a lid using a brazing material. .
[0020]
The conductor layer 2 includes a front surface conductor layer 2a provided on the surface of the substrate bottom 1a, a back surface conductor layer 2b provided on the back surface for electrical connection with the outside, a front surface conductor layer 2a and a back surface conductor layer 2b. And an internal conductor layer 2c formed inside the substrate bottom 1a.
[0021]
The metal bonding layer 3 in the present invention is composed of a metallized layer 3a and a plating layer 3b provided thereon, and has a conduction resistance per unit area of the metal bonding layer 3 (hereinafter simply referred to as a conduction resistance). ) Is 1.0 to 1.3 Ω / cm ² It is important that Conduction resistance is 1.0Ω / cm ² If it is smaller, the electric resistance heat at the time of seam welding is reduced, and poor melting of the brazing material occurs, resulting in 1.3 Ω / cm. ² If it becomes larger, thermal stress increases, and cracks occur in the package.
[0022]
Note that the metallized layer 3a and the plated layer 3b are formed in a ring shape at the end of the substrate bank 1b for the purpose of joining the lid, and serve as a part of the sealing, so that defects such as gas flow are generated. It is needless to say that it is preferable to be provided with a uniform thickness.
[0023]
The measurement of the conduction resistance in the present invention is performed by applying a milliohm tester terminal to a diagonal position on the surface of the plating layer 3b and measuring the result, dividing the area and calculating the electric resistance per area.
[0024]
It is important that the insulating substrate 1 contains alumina as a main component and an alumina-based sintered body containing 4% by mass or more of a sintering aid. By including the sintering aid in an amount of 4% by mass or more, simultaneous sintering with metallization becomes possible, and cost reduction can be achieved. In particular, it is preferable that the sintering aid be contained in an amount of 6% by mass or more, more preferably 8% by mass or more.
[0025]
The main component alumina preferably contains alumina in a proportion of 90% by mass or more, particularly 90 to 96% by mass, more preferably 93 to 96% by mass. Thereby, it becomes easy to further improve the strength and the thermal conductivity of the insulating substrate 1.
[0026]
As a second component, Mn is Mn. ₂ O ₃ It is preferable that the content is included in a ratio of 2 to 8% by mass in conversion. This is because the Mn component acts as a sintering aid, and this Mn component ₂ O ₃ When the amount is less than 2% by mass, densification at 1250 to 1400 ° C. is not achieved, and when the amount is more than 8% by mass, MnAl ₂ O ₄ As a result, the densification is hindered and the strength is reduced. Therefore, in order to enhance sinterability, Mn ₂ O ₃ The amount is particularly preferably 3 to 8% by mass, more preferably 3 to 6% by mass.
[0027]
Further, as a third component, Si is converted to SiO 2 ₂ It is preferable to contain it in a ratio of 1 to 6% by mass in conversion. SiO ₂ When the amount is less than 1% by mass, a liquid phase contributing to the sinterability is not generated and densification is not performed, and when the amount is more than 6% by mass, MnAl ₂ O ₄ Becomes difficult to be crystallized, the amorphous phase increases, and the bending strength decreases. In terms of densification and crystallization, SiO ₂ The amount is particularly preferably 2 to 5% by mass, more preferably 3 to 5% by mass.
[0028]
Also, if desired, at least one of Mg, Ca, Sr, and Ba as a fourth component may be used in an amount of 3% by mass or less in terms of oxide in order to enhance the simultaneous sinterability with the conductor layer 2 and the metallized layer 3a. It may be included in a ratio. Further, if desired, a metal such as W or Mo may be contained as a fifth component at a ratio of 2% by mass or less as a component for blackening the sintered body.
[0029]
At least the second and third components are present at the grain boundaries of the alumina crystal particles. Of these components, Mn as the second component is MnAl ₂ O ₄ It is important to exist as. Mn added as a sintering aid ₂ O ₃ Is MnAl ₂ O ₄ As a result, the bending strength of the sintered body can be increased.
[0030]
According to the present invention, the alumina sintered body forming the insulating substrate 1 preferably has a three-point bending strength of 500 MPa or more, particularly 550 MPa or more, and more preferably 600 MPa or more. By controlling the strength in this manner, it becomes easy to prevent cracks due to thermal stress generated during sealing of the lid or during secondary mounting, impact during handling or use, or the like.
[0031]
The thermal conductivity of the insulating substrate 1 allows the heat at the time of sealing to be quickly released to the outside of the system and reduces the temperature difference within the insulating substrate 1, so that the destruction at the time of sealing is more effectively prevented. From the viewpoint of prevention, it is preferably 15 W / mK or more, particularly preferably 20 W / mK or more, and more preferably 25 W / mK or more.
[0032]
The Young's modulus of the insulating substrate 1 is preferably 320 GPa or less, particularly 310 GPa or less, and more preferably 300 GPa or less, from the viewpoint that thermal stress tends to be absorbed by deformation and breakage is more effectively prevented.
[0033]
According to the present invention, the width d of the substrate bank 1b is set to 0.1 to 0.3 mm, the thickness D of the substrate bottom 1a is set to 0.1 to 0.3 mm, and the height T of the package is set to 0.3. It is preferable to set it to 0.6 mm. By setting such dimensions, the strength of the alumina-based sintered body as the insulating substrate 1 can be taken into consideration, and destruction due to thermal stress at the time of sealing the lid can be more effectively prevented. Can be made smaller.
[0034]
In particular, by setting the height T of the package to 0.6 mm or less, it can be applied to an IC card or the like as an ultra-small and ultra-thin ceramic package on which an electric element and / or a semiconductor element are mounted.
[0035]
The conductive layer 2 contains W and / or Mo as a main component in order to form a metallized layer 3a having a strong adhesion to the insulating substrate 1 by enabling sealing of the lid or connection to various metal terminals. It is preferable to contain 10% by mass or less, particularly 8% by mass or less of alumina.
[0036]
The metallized layer 3a is a material capable of realizing simultaneous firing with the insulating substrate 1, has conductivity, and can contain, for example, W and / or Mo as a main component.
[0037]
According to the present invention, the metallized layer 3a is preferably provided by simultaneous firing. This eliminates the need for a separate step of forming the metallized layer 3a, so that the steps can be shortened, the product cost can be reduced, and the metallized layer 3a having high adhesion can be obtained.
[0038]
The adhesive strength of the metallized layer 3a to the insulating substrate 1 is preferably at least 49N. This prevents the metallized layer 3a from peeling off by improving the adhesive strength, and can further enhance the reliability of bonding and the reliability of sealing.
[0039]
Further, the plating layer 3b is provided for protecting the metallized layer 3a and adjusting the electric resistance of the metal bonding layer 3, and it is important that the plated layer 3b has a lower electric resistance than the metallized layer 3a. By providing such a relationship, the amount of heat generated at the time of seam welding using a desired brazing material can be optimized, and breakage of the insulating substrate 1 can be effectively prevented.
[0040]
It is important that the electric resistance of the plating layer 3b is smaller than that of the metallization layer 3a, and it is particularly preferable to use Ni and / or Au. The electric resistance of Ni and / or Au may be one digit smaller than that of the metallized layer 3a, and the current mainly flows through the plating layer 3b. Therefore, in order to easily perform stable heat generation at a low current and improve heat uniformity, the thickness of the plating layer 3b is preferably set to 8 to 25 μm, particularly 9 to 20 μm, and more preferably 10 to 12 μm, so that cracks and brazing material are generated. This is preferable in that defects such as undissolved residue can be easily prevented.
[0041]
The ceramic package of the present invention is used for mounting an electronic component or a semiconductor element inside, closing and sealing the electronic component or semiconductor element, and is provided on a substrate bottom 11a of an insulating substrate 11, for example, as shown in FIG. The electronic component 14a and the semiconductor element 14b connected to the conductor layer 12 can be placed.
[0042]
The electronic component 14a is electrically connected to the conductor layer 12 using the conductive adhesive 15a. As the electronic component 14a, at least one of a crystal oscillator, a dielectric, a resistor, a filter, and a capacitor can be used.
[0043]
The semiconductor element 14b is connected to the conductor layer 12 by wire bonding 15b.
[0044]
The lid 18 is bonded to a ceramic package and hermetically sealed to protect the electric element 14 bonded to the substrate bottom 11a. The lid 18 is formed by forming a plating layer 13b on the surface of a metallized layer 13a provided in a ring shape on the upper surface of the substrate bank 11b, and further using a eutectic Ag-Cu brazing material 16 thereon, for example, by seam welding. It is joined by the method described above.
[0045]
The lid 18 is preferably made of metal because the thermal expansion is close to that of alumina, the thermal stress generated at the time of sealing is small, and the insulating substrate 11 is less likely to be broken at the time of sealing. Co alloy is good.
[0046]
Next, a method for manufacturing the ceramic package of the present invention will be specifically described.
[0047]
First, as a raw material powder, an alumina powder having an average particle diameter of 0.5 to 2.0 μm, particularly 1.0 to 1.5 μm is prepared as a main component. By setting the average particle diameter to 0.5 μm or more, sheet formability can be ensured and an increase in powder cost can be prevented. Further, when the thickness is 2.0 μm or less, densification by firing at 1400 ° C. or less can be promoted, and sintering can be facilitated.
[0048]
Further, as the second component, Mn having a purity of 99% or more and an average particle size of 0.5 to 5 μm. ₂ O ₃ Powder, SiO 3 having a purity of 99% or more and an average particle diameter of 0.5 to 3 μm as a third component ₂ Prepare powder. Note that Mn and Si may be added as at least one of carbonates, nitrates, and acetates that can form an oxide by firing, in addition to the above oxide powder.
[0049]
These components are based on the alumina powder, ₂ O ₃ 2 to 8% by weight, especially 3 to 8% by weight, more preferably 3 to 6% by weight, ₂ It is preferable to add the powder in an amount of 1 to 6% by mass, particularly 2 to 5% by mass, and more preferably 3 to 5% by mass in order to enhance sinterability and promote densification.
[0050]
If desired, at least one of Mg, Ca and Sr may be added as a fourth component at a ratio of 3% by mass or less in terms of oxide based on a total of 100% by mass of the above components. .
[0051]
Further, as the fifth component, a metal powder or oxide powder of a transition metal such as W or Mo may be added as a coloring component at a ratio of 2% by mass or less in terms of metal. In addition, a group 4a element of Ti, Zr, and Hf, which is a well-known method for improving strength and fracture toughness, may be appropriately added.
[0052]
After appropriately adding an organic binder to the above-mentioned mixed powder, a green sheet for forming an insulating substrate is prepared by a known molding method such as a pressing method, a doctor blade method, a rolling method, and an injection method. For example, after a slurry is prepared by adding an organic binder and a solvent to the mixed powder, a green sheet is formed by a doctor blade method. Alternatively, an organic binder is added to the mixed powder, and a green sheet having a predetermined thickness can be produced by press molding, rolling molding, or the like.
[0053]
Then, if desired, a via hole having a diameter of 50 to 250 μm can be formed in the green sheet by a microdrill, a laser, or the like.
[0054]
On the green sheet prepared in this manner, a conductor paste is printed and applied in a wiring pattern or ring shape on each green sheet by a method such as screen printing or gravure printing. Fill the via hole.
[0055]
As the conductor paste, W and / or Mo is preferably used as a conductor component, to which alumina powder is added in an amount of 10% by mass or less, particularly 8% by mass or less. This can improve the adhesion between the alumina sintered body and the conductor layer while keeping the conduction resistance of the conductor layer low, and can prevent the occurrence of defects such as chipping of the plating. In order to improve the adhesiveness, a powder of the same composition as the oxide ceramic component forming the insulating substrate may be added instead of the alumina powder, and an oxide such as Ni may be added in an amount of 0.05 to 2% by mass. It is also possible to add in a ratio.
[0056]
After that, the green sheets on which the conductive paste is applied by printing are aligned and laminated and pressed, and then the laminated body is heated from at least 1000 ° C. to a maximum firing temperature at a rate of 150 ° C./h or more at a temperature of 1250 to 1400 ° C. It is important to bake in a non-oxidizing atmosphere at a cooling rate up to 1000 ° C. at a rate of 250 ° C./h or less.
[0057]
If the heating rate is less than 150 ° C./h between 1000 ° C. and the firing maximum temperature, the liquid phase generation in the low temperature liquid phase region at the time of heating becomes uneven, and the alumina grain growth is biased. As a result, the bending strength decreases. In particular, in order to further increase the strength, it is preferable that the heating rate be 180 ° C./h or more, and more preferably 200 ° C./h.
[0058]
It is also important to bake at 1250 to 1400 ° C. If the temperature is lower than 1250 ° C., the densification is insufficient and the bending strength does not reach 500 MPa, and if it is higher than 1400 ° C., W and / or Mo itself becomes Sintering progresses, and the bonding strength with alumina decreases, and at the same time, sintering of alumina progresses, which promotes grain growth and increases fracture toughness. The firing temperature is preferably 1350 to 1400 ° C. in order to enhance mechanical and electrical reliability.
[0059]
It is also important that the cooling rate from the holding temperature immediately after the completion of firing to 1000 ° C. is 250 ° C./h or less. When the temperature exceeds 250 ° C./h, MnAl ₂ O ₄ Is hardly crystallized and remains as amorphous, so that the bending strength is reduced. The cooling rate is particularly preferably 200 ° C./h or less from the viewpoint of increasing the strength.
[0060]
It is important that the firing atmosphere is a non-oxidizing atmosphere so that the metal is not oxidized. Specifically, it is desirable to use nitrogen or a mixed gas of nitrogen and hydrogen. For degreasing the organic binder, it is desirable that the atmosphere be a non-oxidizing atmosphere containing hydrogen and nitrogen and having a dew point of + 30 ° C. or lower, particularly 25 ° C. or lower. Note that an inert gas such as argon may be mixed into the atmosphere, if desired.
[0061]
Then, a plating layer made of Ni and / or Au is formed on the ring-shaped metallization layer and the conductor layer.
[0062]
The ceramic package manufactured by such a method can be co-fired with metallization, and can be suitably used as an ultra-thin and small ceramic package.
[0063]
Finally, electronic components and / or semiconductor elements are mounted inside the insulating substrate, electrically connected to the conductor layer, the surface of the ring-shaped metallized layer is covered with a plating layer, and the lid is brazed. By joining the members by seam welding, a semiconductor device in which electronic components and / or semiconductor elements are hermetically sealed can be obtained.
[0064]
【Example】
For alumina powder having a purity of 99% or more and an average particle size of 1.5 μm, Mn having a purity of 99% or more and an average particle size of 0.7 μm is used. ₂ O ₃ Powder, SiO with purity of 99% or more and average particle diameter of 1.0 μm ₂ Powder, W powder having a purity of 99.9% or more and an average particle diameter of 1.2 μm, Mo powder having a purity of 99.9% or more and an average particle diameter of 1.2 μm, purity of 99.9% or more and an average particle diameter of 0.7 μm MgCO ₃ Powder, purity of 99% or more, CaCO having an average particle diameter of 1.3 μm ₃ Powder, SrCO with a purity of 99% or more and an average particle diameter of 1.0 μm ₃ Powder was prepared.
[0065]
After mixing these raw material powders at the ratios shown in Table 1, an acrylic binder was used as a molding organic resin (binder) and toluene was used as a solvent to prepare a slurry, and then the slurry was prepared by a doctor blade method. A 150 μm green sheet was produced. The fifth component and the group 4a element were added at a ratio shown in Table 1 with respect to 100% by mass of the total of alumina, manganese oxide, silicon oxide, the third component and the fourth component.
[0066]
After laminating the obtained green sheets to a predetermined thickness and performing degreasing in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C., the temperature was continuously raised from 1000 ° C. to the maximum firing temperature at a temperature rising rate shown in Table 2, After firing for 1 hour in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C. at the highest firing temperature, cooling was performed at a rate shown in Table 1 up to 1000 ° C.
[0067]
The main crystal phase of the obtained sintered body was identified by crushing the sintered body and X-ray diffraction. Further, the bulk density was measured by the Archimedes method, and the porosity was calculated. The strength was measured at room temperature based on JIS R1601 by preparing a beam-shaped sample having a thickness of 3 mm, a width of 4 mm, and a length of 40 mm. Further, the average crystal particle diameter was measured by an intercept method and expressed as a particle diameter.
[0068]
The Young's modulus was measured at room temperature based on JIS R1602, and the thermal conductivity was measured at room temperature by a laser flash method.
[0069]
On the other hand, Cu, Au and Ag (low resistance metal) were added to W powder having an average particle diameter of 1.2 μm, Mo powder having an average particle diameter of 1.2 μm, and alumina powder having an average particle diameter of 1.5 μm. After preparing the composition as shown in No. 1, an acrylic binder and acetone were mixed as a solvent to prepare a conductor paste.
[0070]
Then, the green sheet produced in the same manner as described above is subjected to a punching process to form a via hole having a diameter of 100 μm, and the via paste is filled in the via hole by a screen printing method, and a wiring pattern is formed. It was printed and applied in the shape of a ring and a ring. In the green sheet on which the ring-shaped metallization was formed, a portion for housing the electric element was removed by punching.
[0071]
The green sheets produced in this manner were aligned and laminated and pressed to produce a laminate. Thereafter, a cutout groove is formed in the laminated body, the molded body is degreased in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C., and then degreased in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C. After the temperature was raised from 1000 ° C. to the maximum firing temperature at the temperature raising rate shown in 1 and firing was performed for 1 hour in a nitrogen-hydrogen mixed atmosphere having a dew point of + 25 ° C. at the maximum firing temperature, the rate shown in Table 1 up to 1000 ° C. And cooled.
[0072]
Next, electrolytic Ni plating was performed on the surfaces of the conductor layer and the ring-shaped metallized layer on the surface of the connection substrate, and further, Au plating was performed on the surfaces. After Au plating, the connecting substrate was broken along the cutout groove to obtain a single ceramic package.
[0073]
The dimensions of the package were measured, and the results are shown in Table 2 where D is the substrate bottom, d is the substrate bank, and T is the package height.
[0074]
A 0.1 mm thick lid made of an Fe-Co-Ni alloy was joined to the ring-shaped metallized layer of each package by seam welding using a eutectic Ag-Cu brazing material, and hermetically sealed.
[0075]
The obtained sample was subjected to a bonding test, metallized peeling and a crack of the insulating substrate were confirmed with a microscope of 40 times magnification, and a sample having no metallized peeling and no crack was indicated by "O", and a sample was indicated by "X".
[0076]
In addition, a sample without metallized peeling or cracking was subjected to a durability test up to 100 cycles with a cycle of holding at −65 ° C. for 5 minutes and 150 ° C. for 5 minutes as one cycle, and the hermetic sealing was evaluated by the He leak method. did. In the He leak method, after holding for 2 hours in a He pressurized atmosphere of 0.41 MPa, the He leak method is taken out, and the amount of He gas detected in a vacuum atmosphere is measured. ^-9 MPa ・ cm ³ 5 × 10 for / sec or less ^-8 MPa ・ cm ³ Those exceeding / sec were evaluated as x, and the results are shown in Table 2.
[0077]
The bonding strength of the ring-shaped metallized layer to the insulating substrate is as follows. After forming a conductor wiring of 2 mm × 25 mm, applying electroless Ni plating, joining the metal fittings using silver brazing, and pulling the metal fittings apart. The peeling load was measured.
[0078]
Finally, the package used for the bonding test was cut, and the thickness of the plating layer was measured by observing a cross section with a scanning microscope. These results are shown in Tables 1 and 2.
[0079]
[Table 1]

[0080]
[Table 2]

[0081]
Sample No. of the present invention 2, 5, 7, 9, and 11 to 31 have a conduction resistance of the metal connection layer of 1.0 to 1.3 Ω / cm. ² No abnormality was found in the bonding test and the sealing test.
[0082]
On the other hand, the sample No. in which the amount of the sintering aid (the total of the main component, the second component, the third component, and the fourth component) is less than 4% by mass and is out of the range of the present invention. In No. 1, the metallization was peeled off from the ceramics in the bonding test, and sufficient sealing could not be performed.
[0083]
Further, the conduction resistance per unit area of the metal bonding layer is 1.0 Ω / cm. ² Sample No. which is lower than the scope of the present invention. In Nos. 3 and 10, sealing failure occurred due to insufficient solder flow in the sealing test.
[0084]
Further, the conduction resistance per area of the metallized layer including the plating layer is 1.3 Ω / cm. ² Higher sample nos. In the bonding tests 4, 6, and 8, cracks were observed at the bottom of the insulating substrate.
[0085]
【The invention's effect】
According to the present invention, by controlling the conduction resistance per unit area of the metal bonding layer, simultaneous firing is possible, and a ceramic package that is not easily broken even when the lid is directly seam-welded to the package can be obtained at low cost. As a result, the width of the substrate bank portion involved in the joining of the lid is 0.1 to 0.4 mm, the thickness of the lower portion of the substrate on which the electronic element is mounted is 0.1 to 0.3 mm, and the height of the package is 0. It can be suitably applied to a ceramic package having a thickness of 0.3 to 0.6 mm.
[0086]
In particular, by controlling the average particle size of the alumina powder, the heating rate and the cooling rate, the three-point bending strength is 500 MPa or more, the Young's modulus is 320 GPa or less, the thermal conductivity is 15 W / mK or more, and the metallizing strength is 49 N or more. And the bonding reliability can be further improved.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an example of a ceramic package of the present invention.
FIG. 2 is a schematic sectional view of the ceramic package of the present invention in which an electric element is mounted inside and a lid is joined.
[Explanation of symbols]
1, 11 ... insulating substrate
1a, 11a ... substrate bottom
1b, 11b ... substrate bank
2 ... conductor layer
2a, 12a ... surface conductor layer
2b, 12b ... back conductor layer
2c, 12c ... inner conductor layer
3 ... Metal bonding layer
3a, 13a ... metallized layer
3b, 13b ... plating layer
14 ... electric element
14a ... electronic parts
14b ... Semiconductor element
15a: conductive adhesive
15b ・ ・ ・ Wire bonding
16 ... brazing material
18 ... lid
D: Thickness of substrate bottom
d: width of substrate bank
T: Package height

Claims (7)

An insulating substrate including a substrate bottom for surface-mounting the electric element and a substrate bank integrally provided on an outer periphery of the substrate bottom; a conductor layer provided inside and / or on a surface of the insulating substrate; A metal bonding layer provided for bonding the lid to at least a part of the substrate bank, wherein the insulating substrate is made of an alumina sintered body containing 4% by mass or more of a sintering aid; The metal bonding layer includes a metallized layer and a plating layer having a lower electric resistance than the metallized layer, and a conduction resistance per unit area of the metal bonding layer is 1.0 to 1.3 Ω / cm ² . A ceramic package, characterized in that: The width of the substrate bank is 0.1 to 0.4 mm, the thickness of the substrate bottom is 0.1 to 0.3 mm, and the package height is 0.3 to 0.6 mm. The ceramic package as described. 3. The ceramic package according to claim 1, wherein the plating layer is made of Ni and / or Au. 4. The ceramic package according to claim 1, wherein said plating layer has a thickness of 8 to 25 [mu] m. The ceramic package according to any one of claims 1 to 4, wherein an adhesion strength of the metallized layer to the substrate bank is 49N or more. The alumina sintered body contains Mn in an amount of 2 to 8% by mass in terms of oxide and Si in an amount of 1 to 6% by mass in terms of oxide, and MnAl ₂ O ₄ is present at a grain boundary of the Al ₂ O ₃ main crystal phase. The ceramic package according to claim 1, further comprising a crystal. The ceramic package according to any one of claims 1 to 6, wherein the alumina sintered body has a strength of 500 MPa or more, a Young's modulus of 320 GPa or less, and a thermal conductivity of 15 W / mK or more.

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