JP2009229253A - Measuring apparatus and quality determination method of dielectric loss tangent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring dielectric loss tangents and method for determining the quality of dielectric loss tangents and capable of easily and accurately determining the quality of dielectric loss tangents in the measuring frequency band between 10 MHz and 1 GHz. <P>SOLUTION: The apparatus for measuring dielectric loss tangents includes a first measuring part 11 for measuring the dielectric loss tangent of a sample in the frequency band of a few MHz, a second measuring part 13 for measuring the dielectric loss tangent of the sample in the frequency band of a few GHz, and a display part 19 for displaying both dielectric loss tangents measured by the first measuring part 11 and the second measuring part 13. Since it is possible to measure the dielectric loss tangent of the sample in the band of a few MHz and the dielectric loss tangent of the sample in the band of a few GHz at the first measuring part 11 and the second measuring part 13 to display both dielectric loss tangents on a display part 19 in such an apparatus for measuring dielectric loss tangents, it is possible to determine that the sample is a conforming item when the higher dielectric loss tangent among the measured dielectric loss tangent in the band of a few MHz, and that the measured dielectric loss tangent in the band of a few GHz is equal to 5×10<SP>-4</SP>or less. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dielectric loss tangent measuring apparatus and a dielectric loss tangent pass / fail judgment method, in particular, members such as an inner wall material (chamber) of a semiconductor manufacturing apparatus, a microwave introduction window, a shower head, a focus ring, a shield ring, The present invention relates to a dielectric loss tangent measuring apparatus and a dielectric loss tangent pass / fail judgment method for measuring a dielectric loss tangent of a corrosion-resistant member that can be suitably used for a stage, a mirror, a mask holder, a mask stage, a chuck, a reticle, and the like of a liquid crystal manufacturing apparatus.

  Conventionally, the alumina sintered body has excellent heat resistance, chemical resistance, and plasma resistance, and also has a low dielectric loss tangent (tan δ) in the high frequency region, so it is used for high frequency plasma device members for semiconductors and liquid crystals. It has been.

  Semiconductor and liquid crystal manufacturing equipment members are in contact with highly reactive halogen-based corrosive gases used for etching and cleaning, and their plasmas, so high corrosion resistance is required. Generally, 99.0% by mass or more There is a need for a high-purity alumina sintered body. On the other hand, the dielectric loss tangent increases from the viewpoint of sinterability as it becomes a high-purity alumina sintered body, which decreases the high-frequency transmittance in the MHz band, increases energy loss, breaks the member due to heat generation, etc. Problems are known to occur.

For reducing the loss of the alumina sintered body, SiO ₂ , CaO, and MgO are included as sintering aids, and the content is controlled to be within a certain range. There is known an alumina sintered body with improved sinter (see, for example, Patent Document 1).

In Patent Document 1, an alumina sintered body is composed of 99.8 to 99.9% by mass of alumina and a grain boundary phase component composed of SiO ₂ , CaO, and MgO with a balance of a predetermined ratio, and at a measurement frequency of 8 GHz. It is described that an alumina sintered body for microwave resonators having a Q value of 10,000 or more (dielectric loss tangent is 0.0001 or less) was obtained.

As in Patent Document 1, an alumina sintered body containing SiO ₂ , CaO, and MgO has a dielectric loss tangent of 0.0001 or less at a measurement frequency of 8 GHz. However, when the dielectric loss tangent in the MHz band is large, for example, when used for a semiconductor that uses a high frequency in the MHz band, a high-frequency plasma device member for liquid crystal, the high-frequency transmittance in the MHz band decreases, Problems such as an increase in energy loss and damage to members have arisen. Furthermore, in recent years, there are applications in a wide frequency range in the MHz to GHz band, and there has been a demand for a low dielectric loss tangent.
JP-A-6-16469

Conventionally, the dielectric loss tangent in the MHz band required for semiconductors, liquid crystal high-frequency plasma apparatus members, etc. has not been so small, and therefore an impedance analyzer (Hewlett Packard) that has a measurement error of about ± 30 × 10 ^−4. It was also possible to directly measure the dielectric loss tangent in the frequency range of 1 MHz to 8.5 GHz using a product made by company: HP-4291A). However, in recent years, the dielectric loss tangent at 10 MHz to 1 GHz is 5 × 10 ⁻⁴ or less. In the measurement by the conventional impedance analyzer, there is a problem that the measurement accuracy is very low and an accurate dielectric loss tangent cannot be obtained at a frequency of 10 MHz to 1 GHz.

  An object of the present invention is to provide a dielectric loss tangent measuring apparatus and a dielectric loss tangent quality determination method that can easily and accurately determine the quality of a dielectric loss tangent in a measurement frequency band of 10 MHz to 1 GHz.

As a result of earnestly examining the method for easily and accurately determining whether or not the dielectric loss tangent at a frequency of 10 MHz to 1 GHz is a set value, for example, 5 × 10 ⁻⁴ or less, the inventors of the present invention have the results of 10 MHz to 1 GHz. Without directly measuring the frequency domain dielectric loss with an impedance analyzer with low measurement accuracy, the dielectric loss tangent in the several MHz band and the dielectric loss tangent in the several GHz band are measured. For example, the dielectric loss tangent at the measurement frequencies of 1 MHz and 8.5 GHz is measured. When the higher one is 5 × 10 ⁻⁴ or less, it is determined as a non-defective product, and the dielectric loss tangent at a frequency of 10 MHz to 1 GHz can be recognized as 5 × 10 ⁻⁴ or less, and the quality of the dielectric loss tangent at a measurement frequency of 10 MHz to 1 GHz is determined. The inventors have found that the determination can be easily and accurately, and have reached the present invention.

  That is, the dielectric loss tangent measuring apparatus of the present invention includes a first measurement unit that measures a dielectric tangent of a sample at a frequency of several MHz band, and a second measurement that measures the dielectric loss tangent of the sample at a frequency of several GHz band of the sample. And a display unit for displaying both the dielectric loss tangent measured by the first measurement unit and the second measurement unit.

In such a dielectric loss tangent measuring apparatus, the dielectric loss tangent of the sample in the several MHz band and the dielectric loss tangent in the several GHz band can be measured by the first measuring unit and the second measuring unit, respectively. Each is displayed on the display. Thereby, by checking the display unit, when the higher dielectric tangent of the measured dielectric loss tangent in the several MHz band and the dielectric loss tangent in the several GHz band is not more than a set value, for example, 5 × 10 ⁻⁴ or less. It is possible to determine that the dielectric loss tangent of the frequency at a frequency of 10 MHz to 1 GHz is 5 × 10 ⁻⁴ or less, and easily and accurately visually confirm whether the dielectric loss tangent at a frequency of 10 MHz to 1 GHz is good or bad. Can be judged.

  Further, the dielectric loss tangent pass / fail judgment method of the present invention measures the dielectric loss tangent of the sample at a frequency of several MHz band and the dielectric loss tangent of the sample at a frequency of several GHz band, and the sample at a frequency of several MHz band and several GHz band. It is determined whether or not the higher one of the dielectric loss tangents is equal to or lower than a set value, and the case where it is equal to or lower than the set value is determined as a non-defective product.

In such a dielectric loss tangent pass / fail judgment method, it is determined whether the higher one of the dielectric loss tangent in the several MHz band and the dielectric loss tangent in the several GHz band of the sample is a set value, for example, 5 × 10 ⁻⁴ or less. determined, in the case where 5 × ^{10 -4} or less, can be recognized as a dielectric loss tangent at the frequency of 10MHz~1GHz is 5 × ^{10 -4} or less, easily and the quality of the dielectric loss tangent at a measuring frequency 10MHz~1GHz Can be judged accurately.

  The dielectric loss tangent pass / fail determination method of the present invention is characterized by measuring the dielectric loss tangent of the sample at a frequency of several MHz band after measuring the dielectric loss tangent of the sample at a frequency of several GHz band. In such a dielectric loss tangent pass / fail judgment method, for example, first, using a network analyzer, a sample made of a disk-shaped alumina sintered body is sandwiched with a jig, and a dielectric loss tangent at 8.5 GHz is obtained. Electrodes can be formed on the upper and lower surfaces of the same sample, the dielectric loss tangent at 1 MHz can be obtained with a capacitance meter, sample processing can be minimized, and dielectric loss tangent measurement at a measurement frequency of 10 MHz to 1 GHz can be further facilitated. Can be done.

In the dielectric loss tangent measuring apparatus of the present invention, the dielectric loss tangent of the sample in the several MHz band and the dielectric loss tangent in the several GHz band can be measured by the first measuring unit and the second measuring unit, respectively. Each is displayed on the display. Thereby, by checking the display unit, when the higher dielectric tangent of the measured dielectric loss tangent in the several MHz band and the dielectric loss tangent in the several GHz band is not more than a set value, for example, 5 × 10 ⁻⁴ or less. Is determined as a non-defective product, and the dielectric loss tangent of the frequency in the frequency range from 10 MHz to 1 GHz can be recognized as being lower than the set value, for example, 5 × 10 ⁻⁴ or less. Easy and accurate judgment.

In the dielectric loss tangent pass / fail judgment method of the present invention, whether the higher one of the dielectric loss tangent in the several MHz band and the dielectric loss tangent in the several GHz band of the sample is not more than a set value, for example, 5 × 10 ⁻⁴ or less. determines, 5 if × ^{10 -4} or less may recognized as dielectric loss tangent at a frequency of 10MHz~1GHz is 5 × ^{10 -4} or less, easily the quality of the dielectric loss tangent at a measuring frequency 10MHz~1GHz And it can be determined accurately.

  The dielectric loss tangent measuring apparatus of the present invention will be described with reference to FIG.

  FIG. 1 shows a dielectric loss tangent measuring apparatus. This dielectric loss tangent measuring apparatus measures a dielectric loss tangent of a sample in a several GHz band and a first measuring unit 11 that measures the dielectric loss tangent of the sample in a several MHz band. 2 measuring unit 13.

  This dielectric loss tangent measuring apparatus includes a first measuring unit 11 having a capacitance meter (manufactured by Hewlett Packard: HP-4278A) on the gantry 15 and a network analyzer (manufactured by Agilent Technologies: 8722ES). The second measuring unit 13 having the above structure is provided, and the upper surface of the gantry 15 is a measuring table 17. Further, on the upper surface of the gantry 15, a display unit 19 that displays both the dielectric loss tangent at several MHz measured by the first measurement unit 11 and the dielectric loss tangent at several GHz measured by the second measurement unit 13 is displayed. Is provided.

  It is desirable that the display unit 19 displays both the dielectric loss tangent at several MHz and several GHz, and the higher one of the dielectric loss tangent at several MHz and several GHz.

  Although not shown, the measurement table 17 is provided with a set table for setting a sample, and also includes a measurement jig for holding the network analyzer sample. In addition, a pair of contact terminals of the capacitance meter are also provided.

  The alumina sintered body containing 99.3% by mass or more of alumina is the number of TE011 modes by the cavity resonator method with the same shape sample when the measurement frequency in the MHz band is 1 MHz, although it depends on the sample shape and the like. Since the resonance frequency of the GHz band is approximately 8.5 GHz, hereinafter, description will be made assuming that several MHz is 1 MHz and several GHz is 8.5 GHz.

In such a dielectric loss tangent measuring apparatus, the dielectric loss tangent of the sample at a frequency of 1 MHz and a frequency of 8.5 GHz can be measured by the first measuring unit 11 and the second measuring unit 13 of one dielectric loss tangent measuring apparatus, respectively. Since both the dielectric loss tangent at the frequency 1 MHz and the frequency 8.5 GHz are displayed on the display unit 19, the higher dielectric loss tangent at the frequency 1 MHz and the frequency 8.5 GHz is equal to or lower than a set value, for example, 5 × 10. ^-4 easily be determined by a is whether a visual or less, in the case where 5 × ^{10 -4} or less can certify dielectric loss tangent at a frequency of 10MHz~1GHz and is 5 × ^{10 -4} or less, The quality of dielectric loss tangent at a measurement frequency of 10 MHz to 1 GHz can be easily and accurately determined. The setting value of the dielectric loss tangent can be arbitrarily set. Hereinafter, the case where the setting value of the dielectric loss tangent is set to 5 × 10 ⁻⁴ will be described.

That is, conventionally, the dielectric loss tangent at a measurement frequency of 1 MHz is measured using a capacitance meter (HP-4278A), and the dielectric loss tangent at a measurement frequency of 8.5 GHz is measured using a cavity resonator method (network analyzer 8722ES). Are known to obtain accurate dielectric loss tangents of ± 2 × 10 ⁻⁴ or less and ± 0.1 × 10 ⁻⁴ or less, respectively, but 1 MHz to 8 required for semiconductor and liquid crystal manufacturing apparatus members .5 GHz, particularly in the frequency range from 10 MHz to 1 GHz, there is only measurement by an impedance analyzer (HP-4291A), and the measurement error is about ± 30 × 10 ⁻⁴ even if it is small, 5 × 10 required in recent years. Measurement accuracy is very low for dielectric loss tangent of ^-4 or less.

Therefore, in the present invention, the dielectric loss tangent at the measurement frequency of 1 MHz and 8.5 GHz is measured without directly measuring the dielectric loss in the frequency range of 10 MHz to 1 GHz with an impedance analyzer with low measurement accuracy, and the measurement frequencies of 1 MHz and 8. since the dielectric loss tangent of the higher dielectric loss tangent in the 5GHz is the case in the range of 5 × ^{10 -4} or less, even in the frequency domain between the measured frequency 10MHz~1GHz is the dielectric loss tangent 5 × ^{10 -4} or less, The sample is treated as a good product, and the dielectric loss tangent at a measurement frequency of 10 MHz to 1 GHz can be easily and accurately determined.

The dielectric loss tangent pass / fail judgment method of the present invention will be described. When the dielectric loss tangent of the sample at a frequency of 1 MHz and a frequency of 8.5 GHz is measured, and the higher one of the dielectric loss tangent of the sample at a frequency of 1 MHz and a frequency of 8.5 GHz is in the range of 5 × 10 ⁻⁴ or less. In addition, since the dielectric loss tangent is 5 × 10 ⁻⁴ or less even in the frequency region between the measurement frequencies of 10 MHz and 1 GHz, the sample is determined as a non-defective product.

  Specifically, first, the dielectric loss tangent of the sample at a frequency of 1 MHz and a frequency of 8.5 GHz is measured. As described above, the measurement includes, for example, the first measurement unit 11 including a capacitance meter (manufactured by Hewlett Packard: HP-4278A) and, for example, a network analyzer (manufactured by Agilent Technologies: 8722ES). Measurement is performed by the second measuring unit 13.

  The measurement by the capacitance meter can be measured based on JIS C2141 by, for example, forming electrodes having a diameter of 37 mm on the upper and lower surfaces of a disk-shaped sample, and bringing a pair of contact terminals into contact with these electrodes.

  In the measurement by the network analyzer, the relative permittivity and the dielectric loss tangent can be calculated from the TE011 mode resonance characteristics of a resonator configured by sandwiching a dielectric substrate between cylindrical cavity resonators divided at the center. The frequency measured by the network analyzer may deviate slightly from 8.5 GHz. This deviation comes from the accuracy of the sample outer dimensions and the dielectric constant variation of the material. In the case of an alumina sintered body sufficiently sintered with a purity of 99.3% or more, 8.5 ± 0.3 GHz is expected.

  As for the dielectric loss tangent of the sample at a frequency of 1 MHz and a frequency of 8.5 GHz, it is desirable to measure the dielectric loss tangent at a frequency of 8.5 GHz with a network analyzer and then measure the dielectric loss tangent at a frequency of 1 MHz with a capacitance meter.

  That is, for example, first, using a network analyzer, a disk-shaped sample is sandwiched between measurement jigs to obtain a dielectric loss tangent at 8.5 GHz, and then electrodes are formed on the upper and lower surfaces of the same sample. The dielectric loss tangent at 1 MHz can be obtained by a meter, the dielectric loss tangent at a frequency of 1 MHz and a frequency of 8.5 GHz can be measured with one sample, sample processing can be minimized, and the dielectric at a measurement frequency of 10 MHz to 1 GHz. It is possible to more easily determine whether the tangent is good or bad.

  The reason why the dielectric loss tangent of the sample at the frequency of 10 MHz to the frequency of 1 GHz can be recognized as being equal to or lower than the higher one of the measured frequency of 1 MHz and the frequency of 8.5 GHz will be described.

For example, the dielectric loss tangent of the alumina sintered body is measured at a frequency of 1 MHz, and it can be confirmed that there is no increase in the dielectric loss tangent due to space charge polarization, interface polarization, and dipole polarization by confirming a value of 5 × 10 ⁻⁴ or less. . Moreover, since the peak due to the increase in the dielectric loss tangent due to these factors is in a frequency band lower than 1 MHz or in the vicinity of several MHz, these factors are observed up to around 1 GHz by confirming 5 × 10 ⁻⁴ or less at 1 MHz. It can be expected that there is no increase in dielectric loss tangent due to.

Further, by confirming that the dielectric loss tangent is 8.5 × 10 ⁻⁴ or less at 8.5 GHz, it can be confirmed that there is no increase in dielectric loss tangent due to ion polarization. Moreover, the peak due to the increase of the dielectric loss tangent due to ion polarization occurs in a frequency band higher than 8.5 GHz or a frequency of several GHz nearby, and by confirming a frequency of 5 × 10 ⁻⁴ or less at 8.5 GHz, it reaches about 1 GHz. Can be expected not to increase the dielectric loss tangent due to the factor of ion polarization.

Thus, for example, by confirming that the higher dielectric tangent of the dielectric tangent at 1 MHz and 8.5 GHz is 5 × 10 ⁻⁴ or less, the dielectric loss tangent is 5 × even in the frequency region between 10 MHz and 1 GHz. It can be recognized that it is 10 ⁻⁴ or less.

  Hereinafter, an example in which the dielectric loss tangent determination method of the present invention is applied to a sample made of an alumina sintered body will be described.

  The alumina sintered body contains 99.3% by mass or more of alumina and 0.7% by mass or less of other subcomponents. By containing 99.3% by mass or more of alumina, it is possible to improve the sinterability and maintain the excellent corrosion resistance, mechanical properties, and electrical properties of alumina. When the amount of the auxiliary component is 0.7% by mass or more, it leads to a decrease in mechanical / electrical characteristics and a decrease in corrosion resistance. Therefore, it is preferable that alumina is 99.3% by mass or more and the auxiliary component is 0.7% by mass or less. Furthermore, in order to be applied as a member for semiconductor and liquid crystal manufacturing equipment, it is necessary to have excellent corrosion resistance against halogen-based plasma, so that alumina should be 99.5% by mass or more and subcomponents should be 0.5% by mass or less. preferable. Alumina is desirably 99.9% by mass or less from the viewpoint of sinterability.

  The alumina sintered body is an alumina sintered body containing alumina crystal particles as main crystal particles and containing Si and M (M is an alkaline earth metal) as an element, and Si at the grain boundaries of the alumina crystal particles. There is a low-loss crystal phase composed of a compound containing Al, M (M is an alkaline earth metal) and an O element. FIG. 2 shows a schematic cross-sectional view of the alumina sintered body. Reference numeral 1 is alumina crystal particles, and reference numeral 2 is a grain boundary.

  In general alumina sintered bodies, subcomponents added as sintering aids exist between the alumina crystal particles as glass or crystals with a high dielectric loss tangent, and tend to increase the dielectric loss tangent of the entire alumina sintered body. was there. However, if a low-loss crystal phase composed of a compound containing Si, Al, M (M is an alkaline earth metal) and O element is precipitated between the alumina crystal particles, the crystal phase itself has a low dielectric loss tangent. The dielectric loss tangent in the MHz band of the entire alumina sintered body can be reduced.

A low-loss crystal phase composed of a compound containing Si, Al, M (M is an alkaline earth metal) and an O element is MAl ₂ Si ₂ O ₈ (M is an alkaline earth metal) from the viewpoint of electrical characteristics. It is preferable that the dielectric loss tangent can be reduced by forming the present crystal. As a low-loss crystal phase composed of a compound containing Si, Al, M (M is an alkaline earth metal) and an O element, in addition, in the composition of MAl ₂ Si ₂ O ₈ (M is an alkaline earth metal) It may be slightly deviated from the stoichiometric composition. Examples of the alkaline earth metal include magnesium, calcium, strontium, and barium. Magnesium, calcium, and strontium are preferable from the viewpoint of dielectric properties and sinterability. Among these, strontium is particularly preferable from the viewpoint of low dielectric loss tangent.

In addition, the compound represented by MAl ₂ Si ₂ O ₈ (M is an alkaline earth metal) is a concept including those in which a part of the constituent elements of M is replaced with other elements.

  The corrosion-resistant member is used as a part for industrial machinery, and can be suitably used as a large and thick member used especially for a semiconductor manufacturing apparatus or a liquid crystal manufacturing apparatus. The semiconductor manufacturing apparatus member refers to an inner wall material (chamber), a microwave introduction window, a shower head, a focus ring, a shield ring, and the like of the semiconductor manufacturing apparatus. The liquid crystal manufacturing apparatus member means a stage, a mirror, a mask holder, a mask stage, a chuck, a reticle, and the like.

With respect to such an alumina sintered body, the dielectric loss tangent at a frequency of 8.5 GHz is measured by a network analyzer, and then the dielectric loss tangent at a frequency of 1 MHz is measured by a capacitance meter. Since the higher one of the dielectric loss tangent of the measurement frequency 1 MHz and the dielectric loss tangent of the measurement frequency 8.5 GHz is 5 × 10 ⁻⁴ or less, the dielectric loss tangent 5 is also obtained in the frequency region between the frequency 10 MHz to 1 GHz. Since it can be recognized as × 10 ⁻⁴ or less, it can be determined as a non-defective product, and the quality of dielectric loss tangent at a measurement frequency of 10 MHz to 1 GHz can be determined easily and accurately.

First, powders of SiO ₂ , SrCO ₃ , CaCO ₃ , and BaCO ₃ were weighed and mixed to obtain compositions shown in Table 1 in terms of SiO ₂ conversion, SrO conversion, CaO conversion, and BaO conversion to obtain a mixed powder. . This powder was heat-treated at 1000 ° C. to 1300 ° C. and pulverized in an alumina ball mill for 48 to 72 hours to produce a raw material powder.

To the Al ₂ O ₃ powder having a purity of 99.95% by mass, the raw material powder of Si, Sr, Ca, Ba and Mg (OH) ₂ powder are added in a proportion as shown in Table 1 in terms of MgO. A predetermined amount of water was added thereto and mixed for 48 hours in an alumina ball mill to form a slurry. The slurry is added to the slurry, dried, granulated, and the mixed powder is molded at a pressure of 1 t / cm ² to produce a cylindrical molded body (diameter 60 mm × height 30 mm). Then, firing was performed in the air to obtain an alumina sintered body having a diameter of 50 mm and a height of 25 mm.

  A sample having a thickness of 1 mm was cut out from the center in the height direction of the obtained sintered body, and the density and dielectric loss tangent were measured. The density was measured by the Archimedes method.

The dielectric loss tangent is measured at 1 MHz, 12 MHz, and 8.5 GHz, and measured using a capacitance meter (HP-4278A), impedance analyzer (HP-4291A), and cavity resonator method (network analyzer 8722ES). I did it. Although the measurement error of the capacitance meter is ± 2 × 10 ⁻⁴ or less and the measurement error of the cavity resonator method is ± 0.1 × 10 ⁻⁴ or less, the measurement error of the impedance analyzer is ± 30 × 10 ^−4. Therefore, when the 12 MHz dielectric loss tangent by the impedance analyzer is less than 5 × 10 ⁻⁴ , it is described in Table 1 as <5.

  In addition, the frequency dependence of the dielectric loss tangent at 1 MHz to 1 GHz was also confirmed by an impedance analyzer. As a result, the dielectric loss tangent at 1 MHz to 1 GHz in this sample tends to be high at 1 to 10 MHz and 100 MHz to 1 GHz and low in the frequency band between them, particularly at 10 to 100 MHz. Tended to be low. Moreover, no peak was observed in the dielectric loss tangent in the frequency band of 10 to 100 MHz, and the shape was flat.

  First, using a network analyzer, a sample having a diameter of 50 mm × thickness 1 mm is sandwiched by a jig to obtain a dielectric loss tangent at 8.5 GHz. Next, using an impedance analyzer, the sample having a diameter of 50 mm × thickness 1 mm is cured. The impedance is obtained by measuring the current and voltage applied to the sample by the high-frequency current-voltage method, and the relative dielectric constant and dielectric loss tangent of 1 MHz to 1 GHz are calculated from the value and the sample thickness. A dielectric loss tangent was determined, and thereafter electrodes were formed on the upper and lower surfaces of the sample having a diameter of 50 mm and a thickness of 1 mm based on JIS C2141, and the dielectric loss tangent at 1 MHz was determined with a capacitance meter.

Moreover, the analysis of the crystal phase in each sintered body is performed by energy dispersive X-ray spectroscopy (EDS) and limited-field electron diffraction using a transmission electron microscope (TEM), and Si, Al, M ( Table 2 shows the presence or absence of MAl ₂ Si ₂ O _8, which is a low-loss crystal phase composed of a compound containing M = Mg, Ca, Sr, Ba) and O elements. In FIG. 8 electron diffraction images were shown.

Further, the average particle diameter _{D 50} of the alumina crystal particles, the scanning electron micrograph of the sample (500 fold) in the range of 0.0432Mm ^2, determine the diameter of each crystal grain in an image analyzer, the average particle calculating the diameter _{D 50,} as described in Table 2.

From Tables 1 and 2, Sample No. containing Si, M (Mg, Ca, Sr, Ba) and O elements as subcomponents in addition to alumina. 1 to 10, a crystal phase composed of a compound containing Si, Al, M (Mg, Ca, Sr, Ba), O element is generated between alumina crystal particles, and the dielectric loss tangent is 5 × at 8.5 GHz. It can be seen that the loss is 10 × ^{4 −4} or less at 1 MHz and 5 × 10 ⁻⁴ or less at 12 MHz.

Therefore, when higher dielectric loss tangent of dielectric loss tangent at 1MHz and 8.5GHz is 5 × ^{10 -4} is found it is 5 × ^{10 -4} at 12 MHz.

It is a schematic diagram which shows a dielectric loss tangent measuring apparatus. It is a schematic sectional drawing which shows the structure of an alumina sintered body. Sample No. 8 is an electron diffraction image of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Alumina crystal grain 2 ... Grain boundary 11 ... 1st measurement part 13 ... 2nd measurement part 15 ... Stand 17 ... Measurement stand 19 ... Display part

Claims (4)

  A first measuring unit for measuring a dielectric loss tangent of a sample at a frequency of several MHz band; a second measuring unit for measuring a dielectric loss tangent of the sample at a frequency of several GHz band; the first measuring unit and the second measuring unit; And a display unit for displaying both of the dielectric loss tangents measured in (1).   Measure the dielectric loss tangent of the sample at a frequency of several MHz band and the dielectric loss tangent of the sample at a frequency of several GHz band, and the higher one of the dielectric loss tangent of the sample at the frequency of several MHz band and several GHz band A dielectric loss tangent pass / fail determination method, wherein it is determined whether or not a set value or less, and a case where the set value or less is determined as a non-defective product.   3. The dielectric loss tangent pass / fail determination method according to claim 2, wherein after the dielectric tangent of the sample at a frequency of several GHz band is measured, the dielectric loss tangent of the sample at a frequency of several MHz band is measured.   4. The dielectric loss tangent pass / fail judgment method according to claim 2, wherein the sample is an alumina sintered body.