JPS63185854A - Low temperature ceramic material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to low temperature fired ceramic materials.

The present low-temperature fired ceramic material is used, for example, particularly in multilayer carrier substrates for mounting IC chips on multilayer substrates for electronic circuits.

[Conventional technology]

With the recent development of miniaturization of electronic devices, there is a demand for increased packaging density on circuit boards. In response to such demands, multilayer wiring using alumina green sheets has been put into practical use. This consists of alternately laminating alumina green sheets and conductor pattern layers and sintering them together.

[Problem that the invention seeks to solve]

The alumina has a high sintering temperature of 1,500 to 1,600° C., and in order to withstand this sintering temperature, electrode materials are naturally limited to molybdenum (Mo), tungsten (W), and the like. Since Mo and W have lower conductivity than silver (Aa), etc., there is a limit to the miniaturization of conductor patterns, and there is a problem that they cannot cope with high density and high speed.

Further, conventional low-temperature firing materials that can be fired at about iooo°C have a low thermal conductivity of 0.01 cal/s-cm-'C or less. For example, in the case of alumina glass, the firing temperature is about 900°C, but the thermal conductivity is as low as 0°006.

Therefore, there is a problem in that ICs and transistors that consume large amounts of power cannot be mounted on this conventional substrate because the temperature of the elements increases due to heat generation.

If there is a ceramic material that has good thermal conductivity and can be sintered at low m (below 1300°C), the above-mentioned problems can be solved. In addition, in the conductive paste with good conductivity,
The limit for Ag-palladium (Pd) system is 13"00℃.Furthermore, if it can be fired at 1000℃ or less, Ag
, to - Platinum (Pt), copper (CU), nickel (Ni)
It is also possible to use pastes such as

The present invention overcomes the above-mentioned drawbacks and
It is an object of the present invention to provide a ceramic material that can be sintered at a low temperature of 1100°C or lower.

[Means for Solving the Problems] (First Invention) The low temperature fired ceramic material of the first invention essentially contains magnesium oxide (MQO') and boron oxide (8gOx).
and the total amount of tlMgo and the B2O3 is 10
When it is 0 mol%, aMaoct5o~90T-le96 and HBtO3 is 10~50 mol%.

In the first invention, Mo0 or Bt03 means a chemical component contained in a ceramic material that is a sintered body,
It may be present in the cough material in the form of a composite oxide such as MgO/Bgo3 or a single oxide of MaO. Further, the raw materials to be mixed before firing may be various oxides, or carbonates, hydroxides, etc. which become various oxides after firing.

Although MQO is originally a substrate material with excellent thermal conductivity and insulation properties, it has drawbacks such as high firing temperature of 1600° C. or higher and large thermal expansion. In the first invention, MgO has 820
By adding 3 and firing, 0.01 cal/
It is possible to achieve thermal conductivity of s-cm-°C or higher, low-temperature firing at 1300°C or lower, and low thermal expansion.

In order to achieve the above-mentioned low-temperature firing, we investigated various ceramic materials and found that MaO・B2O3, 2Mgo-B2O
It has been found that ceramics containing 2,3Mgo-B2O2 as a main component can be fired at a firing temperature of 1300°C or less, have higher thermal conductivity than conventional low-temperature fired materials, and have excellent substrate properties. .

In order to be able to bake at low temperatures and still obtain good substrate properties,
When the total amount of MgO and B2O3 is 100 mol%, the composition ratio of to and B2O3 in IIM is important;
QO is 50 mol% to 90 mol%, and the Btus is 1Q to 5
Must be in the composition range of 0 mol% ・Btus is 50
When MgO exceeds mol% and becomes less than 50% by mol, B2O3
B20. exists in a glassy state and has a coefficient of thermal expansion of less than 0.01, resulting in no improvement in substrate properties. is less than 10 mol%
When gO exceeds 90 mol%, the amount of MgO component present alone increases, making it difficult to sinter at temperatures below 1300'C, making low-temperature sintering impossible.

(Second invention) As described above, the present inventors have proposed a low-temperature fired ceramic material which is made of MgO and BzO3 and can be fired at 1300°C or lower. This material has characteristics such as insulation resistance, dielectric constant, and thermal expansion that are equal to or higher than alumina CAR2o,), and can be fired at low temperatures and simultaneously fired with good conductors such as Ag-Pd, making it an excellent material for multilayer circuit boards. It is effective for

In order to achieve firing at even lower temperatures, we investigated various ceramic materials and found 3Mg0.BZ 03 .

MgO is the main component, and this main component is combined with lithium oxide (Ltd), sodium oxide (Na2O), potassium oxide (K, O), fluorides containing alkali metals, and fluorides containing alkaline earth metals. It has been found that a ceramic material consisting of one type of additive and a sintered body containing only a crystalline phase can be fired at a low temperature of 1100° C. or lower, and also has excellent properties as a substrate.

The low-temperature fired ceramic material of the second invention consists of a main component consisting of 50 to 90 mol% of magnesium oxide and 10 to 50 mol% of boron oxide, and an auxiliary component. Provided is a low-temperature fired ceramic material characterized by comprising at least one endogenous fluoride containing O, Kg O, an alkali metal and an alkaline earth metal-containing fluoride, resulting in a sintered body containing only a crystalline phase. do.

Here, MgO of the present invention and B20. The diagonal line in the triangular diagram shows the ternary state of the low-temperature-fired ceramic material, which consists of the main component consisting of and the supporting component represented by R20.

In the present ceramic material, by adding a predetermined amount of a supplement such as Li2O to the composition of the ceramic material of the first invention, the firing temperature is lowered to 1100°C or higher while substantially maintaining the substrate characteristics. It is. In particular, within the composition range included in the first invention, 3Mg0・BZ
03. Mixed system of MgO (10 to 25 mol% of 8,03)
Then, /M! due to the properties of MgO! It is characterized by its average thermal expansion coefficient and high thermal conductivity, but the firing temperature is 12
The temperature is relatively high at 00-1300°C. In this mixed system, L
By adding a supplement consisting of at least one of iz O, Nag O and K2O, this 3Mg0-BZ
03, the sintering temperature of the MgO mixed system can also be lowered to a low temperature of 1100'C or less.

Furthermore, when the auxiliary component is a fluoride containing an alkali metal or alkaline earth metal, not only can the firing temperature be lowered to 1100°C or less while maintaining almost the substrate properties, but also
It was also possible to significantly improve the density.

MgO1Bz 03 , L t, o, Nag O or ni20 means a chemical component contained in the ceramic material to be sintered, and this material includes, for example, MgO・B, 01
It may exist in the various states of composite oxides such as MgO or single oxides of MgO. Further, the compounded materials before firing may be various oxides, or carbonates, hydroxides, etc. which become various oxides after firing.

In addition, fluorides containing alkali metals or alkaline earth metals are specifically LiF, NaF, and CaF.

and Na5AIFb, etc., which means chemical components contained in the ceramic material to be sintered.

In addition, the subsidy portion is L iz O, N a z O, Kz
O.

It only needs to be composed of at least one of a fluoride containing an alkali metal and an alkaline earth metal, and the same effect can be obtained even when the supplement is composed of two or more kinds.

〔Effect of the invention〕

By adopting the first invention, the present ceramic material has B, 0. Since the addition of MgO lowers the melting point of MgO, low-temperature firing at 1300° C. or lower becomes possible.

Furthermore, although the glass phase has poor thermal conductivity, the ceramic material is considered to be a sintered body of only crystalline phases, and therefore has good thermal conductivity. Therefore, the ceramic material has excellent low-temperature firing at 1,300° C. or lower and thermal conductivity, and has properties such as insulation resistance, dielectric constant, and thermal expansion that are 0.5 to 10% Al. Therefore, it can be fired simultaneously with a good conductor such as Ag-Pb type, and is useful as a multilayer circuit board material.

By employing the second invention, in the present ceramic material, when the auxiliary component is composed of at least one of Lit O, Naz O, and K2O, by adding a predetermined amount of the predetermined auxiliary component, Although the firing temperature decreased significantly, the thermal conductivity did not decrease much, and both low-temperature firing and high thermal conductivity were achieved. This is achieved by adding auxiliary substances such as Li2O, resulting in low melting point Li M g B O2
It is thought that low-temperature firing was achieved due to the formation of , and high thermal conductivity was achieved because the structure after firing consisted entirely of crystalline phases and no glass phase existed.

In addition, if the subsidy portion consists of a fluoride containing an alkali metal or alkaline earth metal, the predetermined subsidy portion is a predetermined amount,
By adding it to the main components, it was possible to perform firing at a low temperature without reducing thermal conductivity, and not only was it possible to obtain high thermal conductivity, but also high density. This is because by adding a small amount of fluoride, a liquid phase mainly composed of fluoride is formed at the grain boundaries at the sintering temperature of the ceramic material, which makes it possible to achieve low-temperature firing and to improve the structure after firing. It is thought that high thermal conductivity and high density could be achieved because the entire structure consisted of crystalline phases and no glass phase existed.

Therefore, the ceramic material of the second invention is Ag, Ag-
Co-firing with a good conductor paste such as PL is also possible, and it is extremely useful, for example, as a material for a multilayer circuit board, compared to conventional materials.

From the above, the ceramic materials of the wood brush 1 and the second invention are as follows:
Both materials have superior low-temperature sintering properties and thermal conductivity compared to conventional materials, making them excellent for miniaturizing conductor patterns and easily removing heat generated by elements, making multilayer circuits that require higher density and higher speeds. It is particularly excellent as a substrate material.

[Experiment example]

The present invention will be explained below using experimental examples.

(Experimental Example 1) This experimental example relates to the ceramic material of the first invention (hereinafter referred to as the blank).

Various ceramic materials were manufactured with various amounts of B2O3 added to MgO, and experiments were conducted to examine changes in thermal conductivity, dielectric constant, thermal expansion, etc. of the ceramic materials.

First, as shown in Table 1, MQOSB2O
The raw materials No. 3 were prepared, and this powder was placed in an alumina pot together with alumina balls and wet mixed for about 8 hours using a ball mill. This raw material powder may be one that becomes an oxide after calcination, such as carbonate or hydroxide, and in this experimental example, magnesium hydroxide (MCI (OH) t ) and boric acid (H803) were used. This mixture was then heated to 600
After calcination for about 4 hours at ℃, dry pulverization was performed in an alumina mortar. Next, a binder such as polyvinyl alcohol was added and granulated.

Thereafter, the aggregates were filled into a mold, pressure-molded at a pressure of about 1 t/Crl, and fired in the atmosphere at 900 to 1400° C. for 2 hours to produce test products (No. 1 to 8). Note that no,
7 is a material made of alumina, and N008 is a material made of alumina glass.

As test products, a disk-shaped sample of 12 mmφ×1llt was prepared for measuring thermal conductivity, dielectric constant, and dielectric loss, and a rod-shaped sample of 5Q mmφ×5 u+×5 mm was prepared for measuring thermal expansion and strength.

Thermal conduction measurements were performed using the laser flash method and v4I.
! To measure the dielectric loss, silver paste was printed concentrically on both sides of the disk sample by screen printing with 250 meshes, and after drying, it was baked in the atmosphere at 760'C to form a circular electrode. did.

Moreover, the thermal expansion coefficient was measured at a temperature change of 20 to 200°C.

The results are shown in Table 1. The composition after firing is based on the results of X-ray diffraction. According to these results, there is a tendency for the firing temperature, coefficient of thermal expansion, thermal conductivity, and dielectric constant to decrease as the amount of B2O2 added increases. When the amount of Bt03 added exceeds 50 mol %, a glass phase is generated in the structure and the thermal conductivity decreases rapidly. Also, if it is less than 10 mol%, the firing temperature is 1300'
C, and cannot be fired simultaneously with Ag-Pd, which is a good conductor. Therefore, in a composition range in which the amount of B2Oxl is 10 to 50 mol%, it is possible to achieve both low-temperature firing of 1300°C or less and high thermal conductivity.

By adopting the above-mentioned composition, it is possible to obtain a circuit board that can be fired at a low temperature of 1300° C. or lower due to the above-described effects. In addition, as shown in Table 1, this substrate has a thermal expansion coefficient of 7.0 to 7.6X10-8/'C1 thermal conductivity of 0.
．． It has excellent properties comparable to alumina, with a value of 0.01 to 0.05 cal/8111.degree. C., and its dielectric constant and dielectric loss are smaller and superior to alumina. It is also possible to co-fire with a commercially available conductor paste, and there is little warping during co-firing, making it suitable for multilayer circuit boards. In addition, the strength is 3-point bending strength: 1000
It has sufficient strength of over kg/cm2.

Because it has good thermal conductivity, it can also be used for multilayer circuit boards that mount elements that consume a lot of power (or generate a lot of heat).

(Experimental Example 2) This experimental example relates to the ceramic material of the second invention.

Tables 2 to 4 show examples of measurements of changes in firing temperature and thermal expansion characteristics of this ceramic material with respect to the added amount of Li2O, Na2O, or auxiliary component. LiF, MaF
Or Nas A/! Tables 5 to 7 show examples of measurements of changes in various properties such as firing temperature and thermal conductivity of this ceramic material with respect to the amount of Fi supplement added. Table 8 shows an example of measuring changes in various properties such as firing temperature and thermal conductivity of this ceramic material with respect to the amount of CaF added. Table 4 shows the addition of 2O, Table 5 shows the addition of LiF, Table 6 shows the addition of NaF, and Table 7 shows the addition of NaF.
Table 8 shows the addition of I F h and Table 8 shows the addition of CaF.

Test items used in this experiment Magnetics 9 to 18 (Table 2), k19
21 (Table 3) and 22 to 23 (Table 4) were prepared in the same manner as in Experimental Example 1, except that a predetermined amount of supplement was added, and each characteristic was measured in the same manner. In addition, the test products included 24-33 (Table 5), Sou 34-35 (Table 6),
Samples Nos. 6 to 43 (Table 7) and Nos. 44 to 52 (Table 8) were prepared in the same manner as in Experiment 1, except that a predetermined amount of supplement was added, and their characteristics were examined in the same manner. Furthermore, in order to investigate the compactness of the ceramic material, the water absorption rate was investigated.

The water absorption rate was measured by determining the weight change between the weight after immersion in pure water for 1 hour and the weight before immersion. Note that the material at 18 is alumina! <Effect of adding Li2O> MgO and B2O, 820. A test product (NtlL 9 to 15.16 or 17, respectively) with a composition ratio of 20.30 or 40 mol %, which is within the range of the first invention, was used.

Further, as shown in Table 2, the composition ratio of Li2O in the material is 0.5 to 11.0 mol% (hereinafter referred to as the margin) when MgO, BtOs and Li2O are all 100 mol%.

The evaluation results of these test products are shown in Table 2.

Test product No. with a LixO composition ratio of 0.5 mol%.

In No. 9, the effect of adding Ll2O was hardly seen. In addition, in test sample No. 15 containing 11 mol%, the insulation properties of the material were poor. Addition of 11 mol % or more produces the effect of lowering the sintering temperature, and addition of 2 mol % or more makes it possible to sinter sufficiently at 950° C. with almost no change. MQO-Bt0
Even if the composition ratio of 3 changes, the relationship between the addition of 1-izQ and the firing temperature is almost the same.

A conventional low-temperature firing material that can be fired at 900°C is alumina glass (alumina + borosilicate!! Lead lath: No. 8 in Table 1). This test item No.

The thermal conductivity of No. 8 is extremely low at 0.008, but this test product No.
o, 10 to 17, the heat conductivity is significantly superior to that of this conventional low temperature fired material.

(MgO-20 mol% B101)-2 mol% LI2O composition test sample No. 7.6
d, Ag-Pb, etc.), and there is little warping during co-firing, making it extremely suitable for multilayer circuit boards. It also has sufficient strength, with a three-point bending resistance strength of 1200 kg/cd or more.

<Effect of addition of 2O to Na2O> Table 3 shows the addition of NagO to a predetermined mixture of 80 mol% MgO and 20 mol% BlO3, and Table 4 shows the addition of □O. The results are shown in the same table.

According to this result, the addition of Na2O or Ni2O
Almost the same effect as in the case of addition was shown. The thermal conductivity is higher when K2O is added (e.g., Nα23) and Na2O is added, compared to when L1□0 is added (for example, test sample No. 13).
Although the value decreases in the order of addition (for example, 21), it shows a significantly larger value when compared with the conventional test sample Nα8 (Table 1) made of alumina glass that can be sintered at low temperatures.

(Leaving space below) Table 3 Table 4 <Effect of addition of LiF> The composition ratio of BzOx in MgO and B2O was within the range of the first invention, 10.20 or 50 mol% of the test product (each Nα30 ~31.24~29, or 32~33)
was used. The composition ratio of LiF in the material is MgO as shown in Table 5.

B, 0. And when the entire LiF is taken as 100 mol%,
It is 0.5 to 11 mol%.

(The following is a blank space) The evaluation results of the test products are shown in Table 5. LiF composition ratio 0
．． In test product No. 24 containing 5 mol %, the effect of adding LiF was hardly observed, and the sintering temperature was hardly lowered. In addition, the insulation property of test sample No. 029 containing 11 mol % was significantly deteriorated. From test product No. 24 to 33,
Even if the composition ratio of MgO and BzO3 changes, by adding 1 to 10 mol% of LiF, it is possible to lower the firing temperature and obtain a highly dense ceramic material with a water absorption of 0%. did it.

<Effect of adding NaF> Na is a fluoride of Na, which is an alkali metal like Li.
F with MgO and B20. Table 6 shows the results when added to a given mixture of

According to this result, NaF showed almost the same effect as the case of adding LiF.

[Effect of adding Na5AIFh] Na, Af, which is a fluoride containing Na, which is an alkali metal
Table 7 shows the results of adding F6 to a given mixture of MgO and B2O3.

As is clear from Table 7, the composition ratio of Na5AeFh is 0.
．． 5 mol% test product No. 36 has N a 3 A e
Almost no effect of Fb addition was observed, and a relatively high firing temperature was observed. In addition, in the test sample Nα39 containing 11 mol%, the insulation properties of the material were significantly impaired. That is,
1 to 10 mol% Na to a predetermined ratio of MgO and 8203
By adding 5AIFh, a ceramic material with low firing temperature and high density could be obtained. Note that even if the composition ratio of Mg0B2Oz changes, N
a= The relationship between the composition temperature and the amount of AIFb added was almost the same.

(The following is a blank space) <Effect of addition of CaF> 0.5 to 16 mol% of CaF2, which is a fluoride containing an alkaline earth metal, was added to a predetermined mixture of MgO and B2O3.

The evaluation results of these test products are shown in Table 8.

Test product No. 4 with a composition ratio of Ca and F of 0.5 mol%
In No. 4, no decrease in the firing temperature was observed, and the effect of adding Ca F z was hardly seen. In addition, in test sample No. 48 containing 16 mol %, the insulation properties of the material became poor. From the test products Nα44 to 52, even if the composition ratio of MgO-820 changes, by setting the addition rate of CaF to 1 to 15 mol%, the firing temperature can be lowered and high density with a water absorption rate of 0% can be achieved. We were able to obtain a ceramic material that had a lot of properties.

(Margin below)

[Brief explanation of the drawing]

The figure is a triangular diagram showing the state of a three-component system showing the composition ratio (shaded area) of each component contained in a low-temperature fired ceramic material consisting of three components: MgO, 3203 (main component), and R2O (supporting bone).

Claims (6)

[Claims] (1) Substantially consists of magnesium oxide (MgO) and boron oxide (B_2O_3), and when the total amount of the magnesium oxide and the boron oxide is 100 mol%, the magnesium oxide is 50 to 90 mol%, and the oxide is A low-temperature-fired ceramic material containing 10 to 50 mol% of boron and forming a sintered body containing only a crystalline phase by firing. (2) The low-temperature-fired ceramic material according to claim 1, wherein the low-temperature-fired ceramic material is fired at 1300° C. or lower. (3) Main components consisting essentially of magnesium oxide (MgO) and boron oxide (B_2O_3), and fluorides and alkaline earths containing lithium oxide (Li_2O), sodium oxide (Na_2O), potassium oxide (K_2O), and alkali metals. and an auxiliary component consisting of at least one kind of fluoride containing a similar metal, and the main components include 50 to 90 mol% of the magnesium oxide and 10 to 90 mol% of the boron oxide, when the total of the main components is 100 mol%. ~50%, and is characterized in that it becomes a sintered body containing only a crystalline phase upon firing. (4) The auxiliary components are lithium oxide (Li_2O), sodium oxide (Na_2O), potassium oxide (K_2O)
and at least one fluoride containing an alkali metal, and when the total of the main component and the auxiliary component is 100 mol%, the main component is 90 to 99 mol%, and the auxiliary component is 1 to 10 mol%. A low-temperature fired ceramic material according to claim 3, characterized in that: (5) The auxiliary component consists of at least a fluoride of an alkaline earth metal, and when the main component and the auxiliary component as a whole are 100 mol%, the main component is 85 to 99 mol%, and the auxiliary component is 1 to 15 mol%. The low-temperature fired ceramic material according to claim 3, characterized in that the content is mol%. (6) The low temperature fired ceramic material according to claim 3, wherein the low temperature fired ceramic material is fired at a temperature of 1100° C. or lower.