JP2750470B2 - Manufacturing method of alumina multilayer wiring board - Google Patents

Description

The present invention relates to a method for manufacturing an alumina multilayer wiring board,
Used for manufacturing various electronic components.

[Conventional technology]

An alumina multilayer wiring board is manufactured by laminating and firing alumina green sheets produced using alumina raw material powder.

The average particle size of the alumina raw material powder usually used is about 1 to 3 μm. On the other hand, when manufacturing a high-precision multilayer wiring board, it is necessary to improve the sinterability of the alumina green sheet, and in order to achieve this purpose, the average particle size is 1.0 μm or less, and the activity is high. Things are used.

[Problems to be solved by the invention]

However, in general, in a multilayer wiring board manufactured by firing in an atmosphere in the presence of a trace amount of oxygen, if such fine particles are used, the pore diameter in the green sheet becomes too small, and the degreasing of the organic binder becomes insufficient. As a result, on the contrary, the sinterability is hindered, and it is difficult to obtain the intended high-precision multilayer wiring board.

The present invention has been made in view of the above viewpoint, and by selecting alumina raw material powder in terms of crystallinity and particle size, the degreasing and sintering properties are improved, and a high-precision multilayer wiring board is obtained. It is intended to provide a method of manufacturing.

[Means for solving the problem]

The method for producing an alumina multilayer wiring board according to the present invention comprises:
In a method for producing an alumina green sheet using an alumina raw material powder, laminating and firing the alumina green sheet, and manufacturing an alumina multilayer wiring board, the alumina raw material powder is obtained by heating the α-alumina (104) face after heating. X
It is characterized in that the raw material powder is an alumina raw material powder whose peak half width by line diffraction is reduced by at least 0.0005 ° as compared with the half width before the heat treatment, and the average particle size of the alumina raw material powder is 3 μm or more.

As described above, the difference between the peak half width by X-ray diffraction before and after the heat treatment was evaluated for the evaluation of the crystallinity of the alumina raw material powder for the following reason. In other words, the measured value of the peak half width itself differs depending on the X-ray diffractometer used, so that the crystallinity cannot be uniformly evaluated. This is because the crystallinity can be universally displayed irrespective of the difference. The reason why the (104) plane was selected as the measurement plane during such X-ray diffraction was as follows:
Although it is common to use a K [alpha ray of Cu as an X-ray source, the K [alpha line is made up from different X-ray a slightly wavelengths of K [alpha ₁ and K [alpha _2. Then, as the angle of X-ray diffraction increases, the influence of the difference in wavelength appears more, and the shape of the peak is distorted. Therefore, in order to accurately evaluate the peak half-value width, it is necessary to select a crystal plane that exhibits a strong diffraction peak at an angle as small as possible, and the (104) plane is a plane that meets this requirement. is there.

The `` decrease in the half width at least 0.0005Å '' means that if there is such a decrease in the half width before and after firing the alumina raw powder, the activity of the alumina raw powder is sufficiently high and the sinterability is good. It is.

The reason why the “average particle size of the alumina raw material powder” is set to 3 μm or more is that if the roughness is such a degree, the pore size in the alumina green sheet becomes large and the degreasing property can be improved. is there.

〔Example〕

 Hereinafter, the present invention will be described specifically with reference to examples.

In this example, first, the influence of the crystallinity and particle size of the alumina raw material powder on the sinterability was examined.

First, the average particle size of the three types of raw material powders A, B, and C, the peak half width before and after the heat treatment, and the difference therebetween were measured.

The average particle size was measured by a laser type particle size distribution measurement method using Microtrade (trade name) manufactured by LEEDS & NORTHHRUP. Then, the particle size value at a cumulative number of 50% was defined as the average particle size. According to this, the average particle diameter of each raw material powder is 3.5 μm for raw material powder A, 2.2 μm for raw material powder B, and 3.6 μm for raw material powder C.

On the other hand, the peak half width is X
It was determined as the peak width at half the peak height in the figure in the line diffraction pattern. The measurement conditions in this case are as follows.

Measurement surface = (104) surface X-ray source = Cu Kα ray (acceleration voltage; 40 kV, current; 100 mA) Step / Sampling = 0.004 deg Background = No reduction Smoothing = Yes Scan Spend = 0.2 deg / min THRESHOLD WIDTH = 0.08 deg FIG. 1 shows an example of the measurement result of the raw material powder A before the heat treatment as an example of the measurement result in this case, and the analysis is as follows.

Peak position (θ); 35.133 ゜ /2=17.5665 ゜ TOTAL = 1506959, BACK = 60157 NET = 1446802 Half width (dθ); 0.189 ゜ /2=0.0945 ゜ The unit of this half width is calculated using the following formula. Converted from the angle to the lattice constant, it is 0.0133 °.

d = λ / 2sin θ (Å) where θ is the diffraction angle, λ is the X-ray wavelength (1.5405
0Å). Similarly, the half width of the A powder after the heat treatment (1550 ° C. × 2 hours) is 0.0122
こ の, and as a result, the decrease in the half-width due to firing was 0.0011.
It became Å.

Furthermore, if the raw material powder B is similarly measured,
The decrease in the half width is 0.0008Å (before heat treatment; 0.0130Å, after heat treatment; 0.0122Å).
0.0002Å (Before heat treatment; 0.0124Å, After heat treatment; 0.0122
Å).

Next, 6% of SiO ₂ was added to 92% of the raw material powder A, and MgCO ₃ and
In a system in which CaCO ₃ was added by 1% in terms of MgO and CaO, respectively, an alumina green sheet having a thickness of 0.6 mm was produced by a known method. Furthermore, this alumina green sheet is
The test pieces A (50 mm × 45 mm × 3.6 mm) were laminated. Test pieces B and C were also prepared for the raw material powders B and C by the same method.

A firing test was performed on each of the test pieces A, B and C in a hydrogen atmosphere while changing the firing temperature. The result is shown in FIG. In the figure, Δ indicates the difference in peak half-width by X-ray diffraction before and after the heat treatment of each of the raw material powders A, B and C.

According to the figure, when using the raw material powder B having a small average particle size of 2.2 μm and a relatively small half width difference of 0.0008,
At 1460 ° C (low temperature range), the sintering density already increased,
Around the temperature exceeding ℃, the sinterability is hindered due to the organic binder remaining in the green sheet, leading to a decrease in the sintering density. This tendency becomes more remarkable as the temperature becomes higher.

In addition, when the raw material powder C having a large average particle size but a small half-value width difference is used as compared with the raw material powder B, the sintering density increases at a high temperature. Low, the sintering progresses rapidly with increasing temperature, and the stable firing region is very narrow.

On the other hand, when the raw material powder A is used, since the average particle size of the raw material powder A is large and excellent in activity, the sintering density gradually increases from a low temperature of less than about 1500 ° C., and the high-density region is wide. Wide stable burning area.

From the above, low crystallinity (high activity) as in raw material powder A
If you select a raw material powder with a large particle size,
In addition, sinterability is improved, and a sintered body having stable quality can be obtained.

Next, the test piece A (the product of the present invention) and the test piece B
Specimens A 'and B' (the dimensions are
It is 120 × 120 × 3.6 (thickness) mm. ) Are prepared in 10 lots each, and the same conditions (1550 ℃
Sintering for 1.5 hours, and a sintered body (about 100 × 100 ×
3.0 (thickness) mm). Then, the dimensions of the width × length of the sintered body were measured to examine the dimensional accuracy.

The dimensional accuracy of the sintered body made from the test piece B 'showed a variation of 0.7% in the section three times the standard deviation, whereas the dimensional accuracy of the sintered body made from the test piece A' was up to 0.2%. Reduced to Therefore, in the product of the present invention, a significant improvement in dimensional accuracy is achieved as compared with the conventional product.

It should be noted that the present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention in accordance with the purpose and application.

〔The invention's effect〕

As described above, by selecting the alumina ceramic from both the crystallinity and the grain size, the degreasing property and the sintering property can be improved, and the sintering property shows high dimensional accuracy because it shows stable sintering property. A multilayer wiring board can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the result of X-ray diffraction of alumina powder before heat treatment for illustrating a method of calculating a half width, and FIG. 2 is a graph showing a relationship between a firing temperature and a sintered body density in Examples. FIG. H; peak height, W; half width

Claims (1)

(57) [Claims] 1. A method for producing an alumina green sheet using an alumina raw material powder, laminating and firing the alumina green sheet to produce an alumina multilayer wiring board, wherein the alumina raw material powder is heated α- Alumina (10
4) Alumina raw material powder whose peak half-width by X-ray diffraction of the surface is reduced by at least 0.0005 ° as compared with the half-width before heat treatment, and wherein the average particle diameter of the alumina raw powder is 3 μm or more. Of manufacturing an alumina multilayer wiring board.