JP4576151B2 - Ceramic composition and ceramic wiring board - Google Patents

Description

The present invention is a ceramic composition containing Sr ₂ SiO ₄ as a main crystal, and a ceramics wiring board using the ceramics composition.

  Along with the improvement of highly integrated technology of electronic components, the mounting density of wiring boards on a mother board is increasing. However, as the connection density increases, the load applied to the connection portion also tends to increase.

  The load applied to the connection site is mainly due to thermal stress, but this thermal stress occurs due to the difference in the coefficient of linear expansion of the connection object. The larger the difference, the stronger the load applied to the connection site. . In addition, since the thermal stress increases with the size of the substrate, the difference in the linear expansion coefficient between the wiring substrate and the mother board is preferably small in order to improve the bonding reliability.

The linear expansion coefficient of the wiring board that has been conventionally used for general purposes is about 7.0 × 10 ⁻⁶ / K or less, whereas the linear expansion coefficient of the motherboard is about 14.0 × 10 ⁻⁶ / K. The difference is large, and a wiring board having a higher linear expansion coefficient than that of a wiring board conventionally used for general purposes is required in order to improve the reliability of bonding between the mother board and the wiring board.

  At present, as information capacity increases and information communication speeds up, it is required to transmit high-frequency signals without loss, and a wiring board with low dielectric loss in the high-frequency region is required. In order to transmit a high-frequency signal without loss, it is required to use a low-resistance metal such as copper or silver as a conductor for forming a wiring layer, but in order to use these low-resistance metals as a conductor material, The substrate material must be able to be fired at a low temperature, and the dielectric loss of the substrate itself must be kept low.

  In order to meet these requirements, various compositions having a high coefficient of linear expansion and compositions having a low dielectric loss have been studied.

For example, in the following Patent Document 1, SiO ₂ is contained in an amount of 17 to 45% by mass, Al ₂ O ₃ is contained in an amount of ₂ to 19% by mass, B ₂ O ₃ is contained in an amount of 0.4 to 9% by mass, and SrO is contained in an amount of 46 to 63% by mass. A glass composition comprising a crystallized glass in which Sr silicate crystals are precipitated from a glass material, the composition being a composition that can be sintered at a low temperature and has a low dielectric loss even in a high frequency region, and uses the composition Thus, it is disclosed that a wiring board having excellent dielectric properties can be obtained.

Further, in Patent Document 2 below, a crystallized glass composition containing SiO ₂ , MgO and CaO, and by heat treatment, at least one crystal phase of merwinite, montericite, and calcium silicate is precipitated. It is disclosed that a wiring board having a high linear expansion coefficient can be obtained by using the composition.

Furthermore, in the following Patent Document 3, a diopside crystal phase and a cordierite crystal phase are contained, the balance is made of a glass phase and / or other ceramic crystal phase, and the open porosity is 1% or less. By using the composition, the linear expansion coefficient is 2.5 to 9.0 × 10 ⁻⁶ / K or more, and the dielectric loss at 60 GHz is 20 × 10 ⁻⁴ or less. It is disclosed that a wiring board having the above characteristics can be obtained.
JP 2003-252678 A JP 2000-185966 A JP 2002-167270 A

  However, in general, silicate crystals have a deep relationship between the linear expansion coefficient and dielectric loss and the crystal structure, and they are generally in a reciprocal relationship, making it difficult to achieve both the high linear expansion coefficient and the low dielectric loss. Met. Other than silicates, crystals with a low dielectric constant of 15 or less and easy to sinter at low temperatures are rare. Even in the compositions of Patent Documents 1 to 3, the physical properties of high linear expansion coefficient and low dielectric loss have not been achieved in a region where the physical properties can be satisfied.

  Moreover, since the technique of the said patent documents 1-3 uses crystalline glass powder as a raw material, there also existed a problem that raw material cost became high and the handleability of a raw material was bad. Furthermore, crystallized glass has a problem that it is difficult to control the degree of crystallinity because of its high crystallization speed.

  Therefore, an object of the present invention is a substrate material that can be fired at a low temperature, has a high linear expansion coefficient, and has a low dielectric loss, can be used for high-frequency transmission, and has high reliability in bonding with a motherboard. It is an object of the present invention to provide a ceramic composition and a ceramic wiring board using the ceramic composition.

In order to achieve the above object, the first ceramic composition for a ceramic wiring board according to the present invention is mainly composed of ceramic powder that is not glass and comprises 18 to 28 parts by mass of SiO ₂ and 72 to 82 parts by mass of SrO in terms of oxide. The component (A) and the boron component (B) comprising at least one powder selected from boron oxide, carbonate, acetate, nitrate, fluoride, and a single metal , the main component (A) 100 It is obtained by firing a raw material containing 1 to 3 parts by mass of the boron component (B) in terms of oxide with respect to parts by mass, and contains Sr ₂ SiO ₄ crystals as main crystals.
The second of the ceramic composition for a ceramic wiring board of the present invention is a main component (A) composed of ceramic powder that is not glass, composed of 18 to 28 parts by mass of SiO ₂ and 72 to 82 parts by mass of SrO , in terms of oxide , and boron. Boron component (B) composed of one or more kinds of powders selected from oxides, carbonates, acetates, nitrates, fluorides and single metals , and alkali metal oxides, carbonates, acetates, nitrates, fluorides And an alkali metal component (C) composed of one or more powders selected from a single metal , and the boron component (B) is 0.5 to 100 parts by mass in terms of oxide with respect to 100 parts by mass of the main component (A). It is obtained by firing 3 parts by mass of a raw material containing 0.1 to 1 part by mass of the alkali metal component (C), and contains Sr ₂ SiO ₄ crystals as main crystals.
Third ceramic wiring substrate for ceramic compositions of the present invention, in terms of oxide, _SiO 2 18 to 28 parts by weight, consists SrO72~82 parts by mass mainly consisting of ceramic powder is not glass (A), boron Boron component (B) composed of one or more kinds of powders selected from oxides, carbonates, acetates, nitrates, fluorides and single metals , and alkali metal oxides, carbonates, acetates, nitrates, fluorides And an alkali metal component (C) composed of one or more powders selected from elemental metals, and one or more elements selected from oxides, carbonates, acetates, nitrates, fluorides and elemental metals of cobalt, silver and alumina. becomes because the auxiliary component composed of powder (D), in terms of oxide with respect to the main component (a) 100 parts by mass of the 0.5 to 3 parts by mass of boron component (B), the alkali metal component (C 0.1 to 1 part by mass, 0.1 to 5 parts by mass of the cobalt component, 0.1 to 1.0 part by mass of the silver component, and 0.1 to 0. It is obtained by firing a raw material containing at least one of 5 parts by mass and contains Sr ₂ SiO ₄ crystals as main crystals.

The ceramic wiring board of the present invention includes a ceramic layer made of the ceramic composition for a ceramic wiring board, and a wiring layer formed of a conductive member laminated on the ceramic layer. And

The ceramic composition of the present invention is a composition having Sr ₂ SiO ₄ crystals having the above composition as the main crystal, and is a composition having a very small content of sub-crystals except for the grain boundary phase. Since the Sr ₂ SiO ₄ crystal is a crystal having a physical property with a high coefficient of linear expansion and a low dielectric loss, the crystal characteristics of the Sr ₂ SiO ₄ can be obtained by using a composition having the Sr ₂ SiO ₄ crystal as a main crystal. A strong composition can be obtained. Moreover, since the said composition contains a boron component, a liquid phase is formed at the time of baking and the firing temperature can be lowered. Therefore, the ceramic wiring board using the composition can be a ceramic wiring board having excellent dielectric characteristics in a high frequency region and high reliability in bonding to the mother board.

The ceramic composition for a ceramic wiring board of the present invention and the ceramic layer of the ceramic wiring board have a linear expansion coefficient of 9.5 × 10 ⁻⁶ / K or more and a dielectric loss of 15 × 10 ⁻⁴ or less. Is preferred. By using the ceramic composition having the above physical properties as a substrate material, it is possible to obtain a ceramic wiring substrate having more excellent dielectric characteristics in a high frequency region and reliability of bonding with a mother board.

The ceramic composition for a ceramic wiring board and the ceramic wiring board of the present invention are preferably sintered at 900 to 1000 ° C. The ceramic wiring board that can be sintered at the above temperature can use a low-resistance metal such as silver or copper as the conductive member. Therefore, a ceramic wiring board capable of transmission in a higher frequency region can be obtained.

The ceramic composition for a ceramic wiring board of the present invention is a ceramic composition that can be sintered at a low temperature and has a high linear expansion coefficient and low dielectric loss. Therefore, the ceramic wiring board using this composition is excellent in high-frequency transmission, and becomes a ceramic wiring board with high reliability of bonding to the mother board.

Main component of the ceramic composition of the present invention (A) is an oxide not glass, it is possible to use a ceramic powder such as carbonates, in particular oxide is preferably used.

Main component of the ceramic composition (A), in terms of oxide, the mixing ratio of SiO _2, and SrO is, _SiO 2 18 to 28 parts by weight, is adjusted to be SrO72~82 parts by mass.

When SiO ₂ is 18 parts by mass or less and SrO is 82 parts by mass or more, Sr ₃ SiO ₅ crystals increase and dielectric loss increases, and SiO ₂ is 28 parts by mass or more and SrO is 72 parts by mass or less. The SrSiO ₃ crystal increases and the linear expansion coefficient decreases.

Moreover, a boron component, an alkali metal component, a cobalt component, a silver component, and an alumina component are used as other components. As these materials, oxides, carbonates, acetates, nitrates, fluorides, simple metals may be used, or glass having a composition having the above ratio may be used in combination. Used.
That is, the 1st of the ceramic composition of this invention consists of a main component (A) and a boron component (B).
Moreover, the 2nd of the ceramic composition of this invention consists of a main component (A), a boron component (B), and an alkali metal component (C).
The third ceramic composition of the present invention is a subcomponent (D) selected from a main component (A), a boron component (B), an alkali metal component (C), a cobalt component, a silver component and an alumina component. ).

In the ceramic composition of the present invention, the boron component, Ru essential der to reduce the firing temperature. In the case of a ceramic composition composed of a main component and a boron component, it is added so as to be 1 to 3 parts by mass in terms of oxide with respect to 100 parts by mass of the main component composed of SiO ₂ and SrO. Moreover, when an alkali metal component, a cobalt component, a silver component, and an alumina component are included in addition to the boron component , 0.5 to 3 in terms of oxide with respect to 100 parts by mass of the main component composed of SiO ₂ and SrO. It adds so that it may become a mass part.

  When the boron component is less than 0.5 parts by mass, it is difficult to fire at 1000 ° C. or less, and when it is more than 3 parts by mass, fusion occurs during firing and the shape of the sintered body becomes difficult to stabilize, and the green sheet The binding property of the binder at the time of molding or the like is lowered and workability is deteriorated.

  Among the above components, the alkali metal component, cobalt component, silver component, and alumina component are not necessarily required, but they are added to effectively reduce the temperature and densify the firing temperature and enhance the low-temperature firing effect. It is a preferred component.

  Among these, as an alkali metal component, Li, Na, K etc. are used, for example, and Li is especially preferable. The alkali metal component is preferably added in an amount of 0.1 to 1 part by mass in terms of oxide, with respect to 100 parts by mass of the main component. If it exceeds, fusion occurs at the time of firing, the shape of the sintered body becomes difficult to stabilize, and the insulating properties are likely to deteriorate.

  The cobalt component is preferably added in an amount of 0.1 to 5 parts by mass in terms of oxide with respect to 100 parts by mass of the main component. If the amount is less than 0.1 parts by mass, the addition effect is poor and exceeds 5 parts by mass. As a result, the dielectric loss increases.

  The silver component is preferably added in an amount of 0.1 to 1.0 part by mass in terms of oxide with respect to 100 parts by mass of the main component. When it exceeds the mass part, the dielectric loss increases.

The alumina component is preferably added in an amount of 0.1 to 0.5 parts by mass in terms of oxide with respect to 100 parts by mass of the main component. When it exceeds the weight part, the dielectric loss increases.

The ceramic composition of the present invention is prepared by mixing raw materials blended so as to have the above composition under wet conditions such as water using ZrO ₂ balls and the like, and if necessary, a binder, a plasticizer, and a solvent. And the like, formed into a predetermined shape, and fired, a ceramic composition having Sr ₂ SiO ₄ of the present invention as a main crystal can be produced. Preferably, among the ceramic raw materials, the main raw material is pre-calcined before use.

  Examples of the binder include polyvinyl butyral resin and methacrylic acid resin. Examples of the plasticizer include dibutyl phthalate and dioctyl phthalate. Examples of the solvent include toluene and methyl ethyl ketone. be able to.

  Molding can be made into a block body using a known press method, formed into a green sheet by a known doctor blade method, further pressed into a laminated body, or formed into a multilayer body using a thick film printing technique in a paste form . In order to form a wiring board, forming into a green sheet is easy to make multilayer.

  In order to form a wiring board, first, the ceramic raw material or the raw material powder containing the calcined powder is formed into a green sheet by using a known doctor blade method. A wiring layer is printed on the green sheet by screen printing using a conductive paste. This green sheet is pressure-bonded to form a laminate. After delaminating this laminate, it is fired at a low temperature of 1000 ° C. or lower, preferably 850 to 950 ° C., to obtain the intended low-temperature fired wiring board. When Ag is used for the wiring, firing is performed in an air atmosphere, and when Cu is used, firing is performed in a reducing atmosphere.

According to the present invention, by a ceramic composition having the above composition ratio, it can be a ceramic composition containing a Sr ₂ SiO ₄ crystal as the predominant crystal. In addition, since the composition is a composition with a very small amount of sub-crystals, it can be a ceramic composition having a high linear expansion coefficient and low dielectric loss. By doing so, a ceramic wiring board having a high coefficient of linear expansion and a low dielectric loss can be obtained.

  The ceramic wiring board of the present invention can be used for, for example, a multilayer wiring board or a semiconductor package. Since the linear expansion coefficient of the substrate is closer to that of the mother board, it is possible to provide an electronic component that can sufficiently maintain the reliability of bonding even when it is increased in size and can perform high-frequency transmission.

[Example 1]
SiO ₂ , SrCO ₃ , Al ₂ O ₃ , B ₂ O ₃ , Li ₂ CO ₃ , Co ₂ O ₃ powder are weighed in the proportions shown in Table 1, and after 15 hours wet mixing, dried at 120 ° C. for 20 hours, The dried powder was calcined at 700 ° C. for 2 hours in the air.

  An appropriate amount of a PVA binder was added to the calcined product, and after granulation and press molding, a binder was removed at 500 ° C. in the atmosphere to obtain a molded body.

  The molded body was fired in the atmosphere at 900 to 1000 ° C. for 2 hours to obtain sintered bodies of sample numbers 1 to 30 shown in Table 2.

Using this sintered body, relative density by Archimedes method, dielectric constant at resonance frequency (10-15GH _Z ) according to JIS R1627, dielectric loss, average linear expansion coefficient in a temperature range of 30 ° C. to 400 ° C. according to JIS R 1618 Was measured.

The dielectric loss was converted to a value at 10 GHz assuming that (frequency) × (1 / dielectric loss) = (constant). This result is also shown in Table 2.

As a result, the ceramic compositions (not marked with *) that fall within the scope of the present invention are all sintered at 1000 ° C. or lower, have a linear expansion coefficient of 9.5 × 10 ⁻⁶ or more, and A physical property having a dielectric loss of 15 × 10 ⁻⁴ or less was obtained.

  On the other hand, a ceramic composition (marked with an asterisk (*)) that is out of the scope of the present invention may not sinter, has a low linear expansion coefficient, or has a problem that the dielectric loss is too large. Recognize.

  Further, based on the above results, the mixing ratio of each element in the ceramic composition is examined as follows.

When SiO ₂ is more than 28% by mass, the production of SrSiO ₃ crystals increases and the linear expansion coefficient decreases (see No. 30). On the other hand, when the content is less than 18% by mass, the generation of Sr ₃ SiO ₅ crystals increases and the dielectric loss increases (see No. 26).

If B ₂ O ₃ is less than 0.5 parts by mass, a dense sintered body cannot be obtained at 1000 ° C. (see No. 1).

When B ₂ O ₃ is more than 3.0 parts by mass, fusion occurs during firing, and the shape of the sintered body is not stable (see No. 6).
When Li ₂ O is more than 1.0 part by weight, it occurs fused during firing, is not stable shape of the sintered body (see No.11).

When Co ₂ O ₃ is more than 5 parts by mass, the dielectric loss increases (see No. 18).

When Ag ₂ O is more than 1.0 part by mass, dielectric loss increases (see No. 22).

When Al ₂ O ₃ is more than 0.5 parts by mass, dielectric loss increases (see No. 13).

Note that Co ₂ O ₃ , Ag ₂ O, and Al ₂ O ₃ are sintered at 1000 ° C. even if not added, but they are added within the above range because there is an effect that the sintering temperature is lowered by the addition. It can be seen that this is preferable.

[Example 2]
SiO ₂ , SrCO ₃ , and powder were weighed in the proportions shown in Table 3, wet mixed for 15 hours, dried at 120 ° C. for 20 hours, and then calcined in air at 1100 ° C. for 2 hours.

To this calcined product, Al ₂ O ₃ , B ₂ O ₃ , Li ₂ CO ₃ and Co ₂ O ₃ powders were weighed and mixed in the proportions shown in Table 3 and then dried at 120 ° C. for 20 hours.

An appropriate amount of a PVA binder was added to this powder, and after granulation and press molding, a binder was removed at 500 ° C. in the atmosphere to obtain a molded body. The molded body was fired at 900 to 1000 ° C. for 2 hours in the air to obtain sintered bodies of sample numbers 31 to 37 shown in Table 2. This fired body was measured in the same manner as in Example 1, and the measurement results are also shown in Table 4.

All the compositions were sintered at 1000 ° C. or less, and a composition having a linear expansion coefficient of 9.5 × 10 ⁻⁶ or more and a dielectric loss of 15 × 10 ⁻⁴ or less was obtained.

  From the above results, if the ceramic composition falls within the scope of the present invention, the process of calcining after mixing the main component with the subcomponent, or the process of adding the subcomponent after precalcining the main component in advance. It can be seen that the same physical properties can be obtained by using either of them.

Ceramics composition of the present invention can be a high frequency transmission, it is possible to provide a high ceramic wiring board reliable bonding between the mother board.

Claims (7)

In terms of oxides, the main component (A) composed of ceramic powder that is not glass, consisting of 18 to 28 parts by mass of SiO ₂ and 72 to 82 parts by mass of SrO, and boron oxide, carbonate, acetate, nitrate, fluoride, and A boron component (B) composed of one or more powders selected from single metals ,
Obtained by firing a raw material containing 1-3 parts by mass of the boron component (B) in terms of oxide with respect to 100 parts by mass of the main component (A),
A ceramic composition for a ceramic wiring board, comprising a Sr ₂ SiO ₄ crystal as a main crystal. In terms of oxides, the main component (A) composed of ceramic powder that is not glass, consisting of 18 to 28 parts by mass of SiO ₂ and 72 to 82 parts by mass of SrO, and boron oxide, carbonate, acetate, nitrate, fluoride, and Boron component (B) composed of one or more powders selected from simple metals and alkali metals composed of one or more powders selected from alkali metal oxides, carbonates, acetates, nitrates, fluorides and simple metals. Consisting of component (C),
A raw material containing 0.5 to 3 parts by mass of the boron component (B) and 0.1 to 1 part by mass of the alkali metal component (C) in terms of oxide with respect to 100 parts by mass of the main component (A) is fired. Is obtained by
A ceramic composition for a ceramic wiring board, comprising a Sr ₂ SiO ₄ crystal as a main crystal. In terms of oxides, the main component (A) composed of ceramic powder that is not glass, consisting of 18 to 28 parts by mass of SiO ₂ and 72 to 82 parts by mass of SrO, and boron oxide, carbonate, acetate, nitrate, fluoride, and Boron component (B) composed of one or more powders selected from simple metals and alkali metals composed of one or more powders selected from alkali metal oxides, carbonates, acetates, nitrates, fluorides and simple metals. Component (C), and an auxiliary component (D) consisting of one or more powders selected from oxides of cobalt, silver and alumina, carbonates, acetates, nitrates, fluorides and elemental metals ,
The boron component (B) is 0.5 to 3 parts by mass, the alkali metal component (C) is 0.1 to 1 part by mass, and the subcomponent is 100 parts by mass of the main component (A). As (D), the raw material containing 0.1-5 mass parts of a cobalt component, 0.1-1.0 mass part of a silver component, and 0.1-0.5 mass part of an alumina component is baked. Is obtained by
A ceramic composition for a ceramic wiring board, comprising a Sr ₂ SiO ₄ crystal as a main crystal. The ceramic composition for a ceramic wiring board according to any one of claims 1 to 3, wherein the coefficient of linear expansion is 9.5 x ^10-6 / K or more and the dielectric loss is 15 x ^10-4 or less. .   The ceramic composition for a ceramic wiring board according to any one of claims 1 to 4, which is sintered at 900 to 1000 ° C. A ceramic layer composed of the ceramic composition for a ceramic wiring board according to any one of claims 1 to 5 ;
A ceramic wiring board comprising a wiring layer formed of a conductive member and laminated on the ceramic layer. The ceramic wiring board according to claim 6 , further comprising a component region formed using the ceramic layer.