JP2006021970A - Method for producing strontium-ruthenium oxide sintered body - Google Patents
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- JFWLFXVBLPDVDZ-UHFFFAOYSA-N [Ru]=O.[Sr] Chemical compound [Ru]=O.[Sr] JFWLFXVBLPDVDZ-UHFFFAOYSA-N 0.000 title claims abstract description 14
- 239000000843 powder Substances 0.000 claims abstract description 56
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims abstract description 45
- 229910001925 ruthenium oxide Inorganic materials 0.000 claims abstract description 41
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 claims abstract description 41
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052707 ruthenium Inorganic materials 0.000 claims abstract description 31
- 238000005245 sintering Methods 0.000 claims abstract description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 22
- 239000001301 oxygen Substances 0.000 claims abstract description 22
- 239000002994 raw material Substances 0.000 claims abstract description 18
- 229910052712 strontium Inorganic materials 0.000 claims abstract description 15
- 239000002245 particle Substances 0.000 claims abstract description 14
- 238000010298 pulverizing process Methods 0.000 claims abstract description 10
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 6
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Inorganic materials [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 claims description 32
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- 238000002441 X-ray diffraction Methods 0.000 claims description 15
- 238000010304 firing Methods 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 229960000935 dehydrated alcohol Drugs 0.000 claims description 3
- 239000000203 mixture Substances 0.000 abstract description 9
- 238000005477 sputtering target Methods 0.000 abstract description 9
- 238000000465 moulding Methods 0.000 abstract description 8
- 238000001354 calcination Methods 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 5
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 14
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 description 10
- 229910000018 strontium carbonate Inorganic materials 0.000 description 10
- 239000010409 thin film Substances 0.000 description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 5
- 230000015654 memory Effects 0.000 description 5
- 229910004121 SrRuO Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000000706 filtrate Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910015801 BaSrTiO Inorganic materials 0.000 description 1
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical class OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 1
- 229920002334 Spandex Polymers 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000009740 moulding (composite fabrication) Methods 0.000 description 1
- 239000004759 spandex Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
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- Inorganic Insulating Materials (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Physical Vapour Deposition (AREA)
- Semiconductor Memories (AREA)
Abstract
Description
本発明は、スパッタリング法による薄膜形成、特に強誘電体メモリーやＤＲＡＭなどにおけるメモリーや誘電体キャパシターなどの各種電子部品の電極形成において、スパッタリングターゲットとして用いるストロンチウム・ルテニウム酸化物（ＳｒＲｕＯ３）焼結体の製造方法に関するものである。 The present invention relates to a strontium-ruthenium oxide (SrRuO 3 ) sintered body used as a sputtering target in the formation of thin films by sputtering, particularly in the formation of electrodes of various electronic components such as memories and dielectric capacitors in ferroelectric memories and DRAMs. It is related with the manufacturing method.
近年、強誘電体メモリー（ＦｅＲＡＭ）の実用化や、ＤＲＡＭの高精度化が盛んに進められている。これらのメモリーのキャパシター用として、例えば、チタン酸ジルコン酸鉛薄膜に電極を取付けた強誘電体薄膜素子や、ＢａＳｒＴｉＯ３などの高誘電体が用いられ、その電極として白金が用いられている。しかし、ＦｅＲＡＭでは、電極が白金のため、分極反転の繰り返しによって強誘電体の分極反転疲労が実用上問題となっている。また、ＤＲＡＭでは、白金のエッチング性や密着性が弱いことが問題となっている。 In recent years, ferroelectric memory (FeRAM) has been put into practical use and DRAM precision has been increased. For these memory capacitors, for example, a ferroelectric thin film element in which an electrode is attached to a lead zirconate titanate thin film, or a high dielectric such as BaSrTiO 3 is used, and platinum is used as the electrode. However, in FeRAM, since the electrode is platinum, the polarization inversion fatigue of the ferroelectric material is a practical problem due to repeated polarization inversion. Further, in DRAM, there is a problem that the etching property and adhesion of platinum are weak.
これらの問題を解決する方法の一つとして、電極を構成する白金の代りに、導電性のストロンチウム・ルテニウム酸化物（ＳｒＲｕＯ３）を用いることが提案されている。しかしながら、電極形成にスパッタリングターゲットとして用いるストロンチウム・ルテニウム酸化物焼結体は、密度が低いものしか製造できないため、強誘電体薄膜上に形成したストロンチウム・ルテニウム酸化物薄膜の密着性が劣っているという問題があった。また、焼結体原料として一般に炭酸ストロンチウムと酸化ルテニウムが使用されているが、酸化ルテニウムは高価であるためコストが高くなるという問題もある。 As one method for solving these problems, it has been proposed to use conductive strontium / ruthenium oxide (SrRuO 3 ) instead of platinum constituting the electrode. However, since the strontium-ruthenium oxide sintered body used as a sputtering target for electrode formation can only be manufactured with a low density, the adhesion of the strontium-ruthenium oxide thin film formed on the ferroelectric thin film is inferior. There was a problem. Further, although strontium carbonate and ruthenium oxide are generally used as the sintered body raw material, there is a problem that the cost is increased because ruthenium oxide is expensive.
例えば、特開２０００−１２８６３８号公報には、炭酸ストロンチウムと酸化ルテニウムを仮焼成し、得られたルテニウム酸ストロンチウム仮焼粉を成形して焼結し、ルテニウム酸ストロンチウム焼結体からなるスパッタリングターゲットを製造する方法が記載されている。しかし、原料として高価な酸化ルテニウムを用いると共に、得られるルテニウム酸ストロンチウム焼結体の密度は実施例によれば４.２ｇ／ｃｍ３程度であり、理論密度（約６.４９ｇ／ｃｍ３）に対して約６５％に過ぎない。そのため、これを真空中でスパッタリングしても、密着性に優れたルテニウム酸ストロンチウムの薄膜を得ることが困難であった。 For example, in Japanese Patent Laid-Open No. 2000-128638, strontium carbonate and ruthenium oxide are calcined, the obtained strontium ruthenate calcined powder is molded and sintered, and a sputtering target made of a sintered strontium ruthenate is used. A method of manufacturing is described. However, while using expensive ruthenium oxide as a raw material, the density of the obtained strontium ruthenate sintered body is about 4.2 g / cm 3 according to the example, and the theoretical density (about 6.49 g / cm 3 ). In contrast, it is only about 65%. Therefore, even if this is sputtered in vacuum, it is difficult to obtain a thin film of strontium ruthenate having excellent adhesion.
また、特開２００２−２１１９７８号公報には、酸化ルテイウムに対して金属ルテニウムが０.１〜４.５重量％含まれた原料を用い、加圧した酸素雰囲気中で焼結するストロンチウム・ルテニウム酸化物焼結体の製造方法が記載されている。この方法によれば、ストロンチウム・ルテニウム酸化物焼結体の密度を６９％以上に、最大で約８０％にすることができる。しかし、原料として高価な酸化ルテニウムを用いるうえ、酸素加圧炉を用いて２×１０５Ｐａ以上の加圧酸素雰囲気中で焼結する必要があった。 Japanese Patent Laid-Open No. 2002-211978 discloses strontium / ruthenium oxide that is sintered in a pressurized oxygen atmosphere using a raw material containing 0.1 to 4.5% by weight of metal ruthenium with respect to ruthenium oxide. A method for manufacturing a sintered body is described. According to this method, the density of the strontium-ruthenium oxide sintered body can be increased to 69% or more and about 80% at the maximum. However, it is necessary to use expensive ruthenium oxide as a raw material and to sinter in a pressurized oxygen atmosphere of 2 × 10 5 Pa or more using an oxygen pressurizing furnace.
従来の方法で製造されるストロンチウム・ルテニウム酸化物焼結体は密度が低いため、これをスパッタリングターゲットとして強誘電体薄膜上にスパッタリングしても、得られる薄膜は密着性に劣っているという問題があった。また、焼結体の原料として一般に炭酸ストロンチウムと酸化ルテニウムが使用されているが、酸化ルテニウムは高価であるため、コスト高になるという問題もあった。 Since the strontium / ruthenium oxide sintered body produced by the conventional method has a low density, there is a problem that even if the strontium / ruthenium oxide sintered body is sputtered onto a ferroelectric thin film as a sputtering target, the resulting thin film has poor adhesion. there were. In addition, strontium carbonate and ruthenium oxide are generally used as raw materials for the sintered body. However, since ruthenium oxide is expensive, there is a problem that the cost is increased.
本発明は、このような従来の事情に鑑み、酸化ルテニウムより安価なルテニウム原料を用い、しかも加圧炉などを用いて加圧酸素雰囲気中で焼結する必要がなく、スパッタリングターゲットとして所定の組成を有するストロンチウム・ルテニウム酸化物焼結体を、簡単且つ低コストで製造する方法を提供することを目的とする。 In view of such a conventional situation, the present invention uses a ruthenium raw material cheaper than ruthenium oxide, and does not need to be sintered in a pressurized oxygen atmosphere using a pressure furnace or the like, and has a predetermined composition as a sputtering target. It is an object of the present invention to provide a method for producing a strontium / ruthenium oxide sintered body having a simple and low cost.
ストロンチウム・ルテニウム酸化物焼結体の密度の向上とコストの低減を図るため、その製造方法及びルテニウム原料に着目して検討を重ねた結果、安価な金属ルテニウムを用い、且つその粒度を調整することで反応性が向上し、仮焼成によって異相のない所定組成のストロンチウム・ルテニウム酸化物が得られること、及びこの仮焼粉を成形して焼結することにより、焼結体密度の向上を達成できることを見出した。 In order to improve the density of strontium-ruthenium oxide sintered bodies and reduce the cost, as a result of repeated investigations focusing on the manufacturing method and ruthenium raw materials, use inexpensive metal ruthenium and adjust the particle size. The strontium-ruthenium oxide having a predetermined composition without any different phase can be obtained by pre-firing, and the density of the sintered body can be improved by molding and sintering this calcined powder. I found.
即ち、本発明が提供するストロンチウム・ルテニウム酸化物焼結体の製造方法は、ストロンチウム源とルテニウム源からなる原料粉を酸素雰囲気中で仮焼成し、得られた仮焼粉を粉砕して成形し、酸素雰囲気中で焼結するストロンチウム・ルテニウム酸化物焼結体の製造方法であって、上記ルテニウム源として、最大粒子径が１０５μｍ以下、Ｄ５０が５〜２５μｍの金属ルテニウム粉末を用いることを特徴とする。 That is, the method for producing a strontium-ruthenium oxide sintered body provided by the present invention is a method of calcining raw material powder comprising a strontium source and a ruthenium source in an oxygen atmosphere, and pulverizing and molding the obtained calcined powder. A method for producing a strontium / ruthenium oxide sintered body sintered in an oxygen atmosphere, wherein a metal ruthenium powder having a maximum particle size of 105 μm or less and a D50 of 5 to 25 μm is used as the ruthenium source. To do.
上記本発明のストロンチウム・ルテニウム酸化物焼結体の製造方法においては、前記仮焼成温度が８５０〜１１００℃、並びに焼結温度が１５５０〜１７５０℃であることが好ましい。また、前記仮焼粉を粉砕する際の媒体として、水分量０.００５％以下の脱水アルコールを用いることが好ましい。 In the method for producing a strontium / ruthenium oxide sintered body according to the present invention, the temporary firing temperature is preferably 850 to 1100 ° C., and the sintering temperature is preferably 1550 to 1750 ° C. Moreover, it is preferable to use dehydrated alcohol having a water content of 0.005% or less as a medium for pulverizing the calcined powder.
上記本発明のストロンチウム・ルテニウム酸化物焼結体の製造方法では、前記粉砕後の仮焼粉のＸ線回折パターンにおいて、２θ＝３２度のピーク強度に対する２θ＝２８.０８度及び２θ＝３５.０１度付近のピーク強度比が共に０.０１以下であることが好ましい。 In the method for producing a strontium-ruthenium oxide sintered body according to the present invention, in the X-ray diffraction pattern of the calcined powder after pulverization, 2θ = 28.08 degrees and 2θ = 35. It is preferable that both peak intensity ratios near 01 degrees are 0.01 or less.
本発明によれば、ルテニウム原料として安価な金属ルテニウムを使用でき、且つ加圧酸素雰囲気中で焼結する必要がないため、ストロンチウム・ルテニウム酸化物焼結体を低コストで製造することができる。また、製造工程途中での異相の発生や成分元素の溶出を抑え、所定組成で高密度のストロンチウム・ルテニウム酸化物焼結体を安定して製造することができる。 According to the present invention, an inexpensive metal ruthenium can be used as a ruthenium raw material, and since it is not necessary to sinter in a pressurized oxygen atmosphere, a strontium-ruthenium oxide sintered body can be produced at a low cost. In addition, it is possible to stably produce a high-density strontium / ruthenium oxide sintered body with a predetermined composition by suppressing the occurrence of heterogeneous phases and elution of component elements during the production process.
従って、本発明のストロンチウム・ルテニウム酸化物焼結体は、所定組成で高密度であるため、スパッタリングターゲットとして用いたとき、密着性に優れた薄膜を形成することができる。特にメモリーや誘電体キャパシターなどの各種電子部品の製造において、電極形成用のスパッタリングターゲットとして使用すれば、強誘電体上に密着性に優れた電極を形成することができる。 Therefore, since the strontium / ruthenium oxide sintered body of the present invention has a predetermined composition and a high density, when used as a sputtering target, a thin film having excellent adhesion can be formed. In particular, when used as a sputtering target for electrode formation in the manufacture of various electronic components such as memories and dielectric capacitors, an electrode having excellent adhesion can be formed on the ferroelectric.
本発明におけるストロンチウム・ルテニウム酸化物焼結体の製造においては、通常のごとく、原料としてストロンチウム（Ｓｒ）源とルテニウム（Ｒｕ）源を用い、酸素雰囲気中で仮焼成し、得られた仮焼粉を粉砕して成形し、酸素雰囲気中で焼結する。使用するストロンチウム源は、従来から一般に使用されているものでよく、例えば、炭酸ストロンチウム、酸化ストロンチウムなどが使用できるが、大気中で安定な炭酸ストロンチウムが最も好ましい。 In the production of a strontium / ruthenium oxide sintered body according to the present invention, as usual, a strontium (Sr) source and a ruthenium (Ru) source are used as raw materials, and calcined in an oxygen atmosphere. Is pulverized and molded, and sintered in an oxygen atmosphere. The strontium source to be used may be one that has been conventionally used. For example, strontium carbonate and strontium oxide can be used, but strontium carbonate that is stable in the atmosphere is most preferable.
一方、ルテニウム源としては、本発明では、従来一般に使用されていた高価な酸化ルテニウムに代えて、安価な金属ルテニウムを用いる。金属ルテニウムの粒子径は、最大粒子径が１０５μｍ以下であること、且つＤ５０が５〜２５μｍであることを必要とする。最大粒子径が１０５μｍを超えるか、又はＤ５０が２５μｍを超えると、反応性が悪くなり、低温での仮焼成が困難になると共に、仮焼粉中に異相が発現し、最終的な焼結体の密度が低下する。また、Ｄ５０が５μｍ未満の金属ルテニウムを用いても、焼結体密度の更なる向上は見られず、粉砕コストが高くなるため好ましくない。 On the other hand, as the ruthenium source, in the present invention, an inexpensive metal ruthenium is used instead of the expensive ruthenium oxide generally used conventionally. The particle diameter of metal ruthenium requires that the maximum particle diameter be 105 μm or less and D50 be 5 to 25 μm. When the maximum particle size exceeds 105 μm or D50 exceeds 25 μm, the reactivity deteriorates, and calcining at a low temperature becomes difficult, and a heterogeneous phase appears in the calcined powder. The density of the is reduced. Further, even when metal ruthenium having a D50 of less than 5 μm is used, the density of the sintered body is not further improved, and the pulverization cost increases, which is not preferable.
これらのストロンチウム源とルテニウム源からなる原料粉は、所定の組成比になるように秤量し、例えばジルコニアボールを用いたボールミルで混合し、乾燥する。次に、この原料粉を仮焼成するが、金属ルテニウムを用いることで反応性が向上するため、酸素雰囲気中において８５０〜１１００℃の低い温度で仮焼成することができる。得られるストロンチウム・ルテニウム酸化物の仮焼粉は、異相の発生が極めて少なく、Ｘ線回折パターンの２θ＝３２度に、ストロンチウム・ルテニウム酸化物（ＳｒＲｕＯ３）の極めて強いピークが存在する。 These raw material powders composed of a strontium source and a ruthenium source are weighed so as to have a predetermined composition ratio, mixed with a ball mill using, for example, zirconia balls, and dried. Next, although this raw material powder is calcined, since the reactivity is improved by using metal ruthenium, it can be calcined at a low temperature of 850 to 1100 ° C. in an oxygen atmosphere. The obtained calcined powder of strontium / ruthenium oxide has very few heterogeneous phases, and an extremely strong peak of strontium / ruthenium oxide (SrRuO 3 ) exists at 2θ = 32 degrees in the X-ray diffraction pattern.
また、原料として用いる金属ルテニウムの最大粒子径が１０５μｍを超えるか又はＤ５０が２５μｍを超え、若しくは仮焼成の温度が８５０℃未満である場合などには、異相が発生しやすくなり、例えば２θ＝２８.０８度付近にＲｕＯ２に起因すると思われるピークが、また２θ＝３５.１度付近にＲｕに起因すると思われるピークが認められるようになる。従って、２θ＝３２度のピーク強度に対する２θ＝２８.０８度及び２θ＝３５.０１度付近のピーク強度比が０.０１より小さいことが好ましく、このピーク強度比が０.０１より大きくなると、異相が多くなるため、最終的な焼結体の焼結密度が低下する。 Further, when the maximum particle diameter of the metal ruthenium used as a raw material exceeds 105 μm, D50 exceeds 25 μm, or the temperature of pre-baking is less than 850 ° C., a heterogeneous phase is likely to occur, for example 2θ = 28. A peak that seems to be attributed to RuO 2 is observed in the vicinity of 0.08 degrees, and a peak that is considered to be attributed to Ru is observed in the vicinity of 2θ = 35.1 degrees. Accordingly, the peak intensity ratio around 2θ = 28.08 degrees and 2θ = 35.01 degrees with respect to the peak intensity of 2θ = 32 degrees is preferably smaller than 0.01, and when this peak intensity ratio is larger than 0.01, Since the number of different phases increases, the sintered density of the final sintered body decreases.
次に、上記仮焼成により得られたストロンチウム・ルテニウム酸化物の仮焼粉は、例えばジルコニアボールを用いたボールミルで粉砕して乾燥する。しかしながら、この仮焼粉の粉砕時に、通常のごとく水中でボールミル粉砕すると、乾燥後に炭酸ストロンチウムが出現しやすい。これは、ストロンチウム・ルテニウム酸化物中のストロンチウムの一部が水中に溶出し、その後の乾燥時に空気中の炭酸ガスと反応して炭酸ストロンチウムとなるためと考えられる。かかるストロンチウムの溶出は、組成のずれを生じさせるため避けるべきである。 Next, the calcined powder of strontium / ruthenium oxide obtained by the calcining is pulverized by, for example, a ball mill using zirconia balls and dried. However, when this calcined powder is pulverized, if it is ball milled in water as usual, strontium carbonate tends to appear after drying. This is presumably because a part of strontium in the strontium / ruthenium oxide elutes into water and reacts with carbon dioxide in the air during drying to become strontium carbonate. Such elution of strontium should be avoided because it causes a compositional shift.
そこで、本発明においては、仮焼成粉を粉砕する際に、ストロンチウムが溶出しない媒体を用いて粉砕することが好ましい。ストロンチウムが溶出しない媒体としては、水分量０.００５％以下の脱水アルコール、例えば、脱水したメチルアルコールやプロピルアルコールなどが好ましく、脱水したフロリナートなども用いることができる。尚、仮焼成粉を粉砕し乾燥して得られる粉砕粉は、約０.６μｍ程度の平均粒子径とすることが好ましい。 Therefore, in the present invention, it is preferable to grind using a medium in which strontium does not elute when the calcined powder is pulverized. As a medium from which strontium does not elute, dehydrated alcohol having a water content of 0.005% or less, such as dehydrated methyl alcohol or propyl alcohol, is preferable, and dehydrated fluorinate can also be used. In addition, it is preferable that the pulverized powder obtained by pulverizing and drying the calcined powder has an average particle diameter of about 0.6 μm.
その後、粉砕粉に有機バインダーを添加し、造粒した後、所定形状に成形し、酸素雰囲気中において５２０℃程度の温度で脱バインダーを行なう。次に、脱バインダーした成形体を、酸素雰囲気中において１５５０〜１７５０℃で焼結することにより、ストロンチウム・ルテニウム酸化物焼結体が得られる。その際、ジルコニアセッターの上に上記仮焼粉又は粉砕粉若しくはこれらと同組成の粉末を敷き、その上に成形体を配置して焼結することが望ましい。 Thereafter, an organic binder is added to the pulverized powder, granulated, formed into a predetermined shape, and debindered at a temperature of about 520 ° C. in an oxygen atmosphere. Next, the strontium / ruthenium oxide sintered body is obtained by sintering the debindered molded body at 1550 to 1750 ° C. in an oxygen atmosphere. At that time, it is desirable to lay the calcined powder, the pulverized powder or a powder having the same composition on the zirconia setter, and dispose the molded body thereon to sinter.
得られるストロンチウム・ルテニウム酸化物焼結体は、従来の製造方法に比べて密度が高くなり、具体的には相対密度が７５％以上となる。そのため、本発明のストロンチウム・ルテニウム酸化物焼結体は、スパッタリングターゲットとして用いたとき、密着性に優れた薄膜を形成することが可能である。 The obtained strontium / ruthenium oxide sintered body has a higher density than that of the conventional manufacturing method, and specifically has a relative density of 75% or more. Therefore, the strontium / ruthenium oxide sintered body of the present invention can form a thin film having excellent adhesion when used as a sputtering target.
酸素雰囲気中での１５５０〜１７５０℃の焼結によって密度が上昇するのは、ストロンチウム・ルテニウム酸化物からのルテニウムの蒸発が抑えられ、更に酸素が焼結に強く寄与するためと考えられる。焼結温度が１５５０℃未満では焼結が進まず、焼結体密度が低くなるため好ましくない。また、焼結温度が１７５０℃を超えても、更なる焼結密度の向上が見込めないだけでなく、加熱炉の耐熱性を高める必要があり、且つ電力コストが増加するため好ましくない。 The reason why the density is increased by sintering at 1550 to 1750 ° C. in an oxygen atmosphere is considered to be that the evaporation of ruthenium from the strontium / ruthenium oxide is suppressed, and that oxygen further contributes strongly to the sintering. If the sintering temperature is less than 1550 ° C., the sintering does not proceed and the density of the sintered body is lowered, which is not preferable. Further, if the sintering temperature exceeds 1750 ° C., it is not preferable since further improvement of the sintering density cannot be expected, and it is necessary to increase the heat resistance of the heating furnace, and the power cost increases.
［実施例１］
最大粒子径が５０μｍで、Ｄ５０が１２.１２μｍの金属ルテニウムと、Ｄ５０が０.７μｍの炭酸ストロンチウムを、ＳｒＲｕＯ３となるように秤量し、純水を媒体にしてジルコニアボールを用いたボールミルで１５時間混合した後乾燥した。得られた混合原料粉を９５０℃で２時間仮焼成した後、仮焼粉を脱水エタノール（水分量０.００５％未満）を媒体にしてジルコニアボールを用いたボールミルで１５時間粉砕し、５０℃で乾燥して粉砕粉とした。
[Example 1]
Metal ruthenium having a maximum particle size of 50 μm, D50 of 12.12 μm, and strontium carbonate having a D50 of 0.7 μm were weighed so as to be SrRuO 3, and a ball mill using zirconia balls with pure water as a medium was used. After mixing for hours, it was dried. The obtained mixed raw material powder was calcined at 950 ° C. for 2 hours, and then the calcined powder was pulverized for 15 hours in a ball mill using zirconia balls using dehydrated ethanol (moisture content of less than 0.005%) as a medium. And dried to a pulverized powder.
上記の仮焼粉は、Ｘ線回折により分析した結果、ストロンチウム・ルテニウム酸化物であることが確認できた。また、仮焼粉について、Ｘ線回折により２θ＝３２度のピーク強度を１としたピーク強度比を調べたところ、２θ＝２８.０８度のピーク強度比は０.００３、及び２θ＝３５.０１度のピーク強度比は０.００２であった。更に、仮焼粉の粉砕後のスラリーを濾過して、濾液を分析したところ、濾液中のＳｒ量は１ｍｇ／ｍｌ以下であり、Ｓｒが媒体中にほとんど溶出していないことが分った。 As a result of analyzing the calcined powder by X-ray diffraction, it was confirmed that it was strontium / ruthenium oxide. Further, the calcined powder was examined by X-ray diffraction for a peak intensity ratio with a peak intensity at 2θ = 32 degrees of 1, and the peak intensity ratio at 2θ = 28.08 degrees was 0.003 and 2θ = 35. The peak intensity ratio at 01 degree was 0.002. Furthermore, when the slurry after calcination of the calcined powder was filtered and the filtrate was analyzed, it was found that the amount of Sr in the filtrate was 1 mg / ml or less, and Sr was hardly eluted in the medium.
上記粉砕粉に有機バインダーを添加してライカイ機で造粒し、冷間静水圧プレスにより圧力２ｔｏｎ／ｃｍ２で成形した。この成形体を酸素雰囲気中において５０℃／時間で昇温し、５２０℃で１時間保持して脱バインダーを行った。次に、ジルコニアセッター上に上記仮焼粉と同組成の粉末を敷き、その上に成形体を配置して、酸素雰囲気中において１００℃／時間で昇温し、１７００℃で１時間焼結した。得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は８１％であった。 An organic binder was added to the pulverized powder, granulated with a lycra machine, and molded at a pressure of 2 ton / cm 2 by a cold isostatic press. The molded body was heated at 50 ° C./hour in an oxygen atmosphere and held at 520 ° C. for 1 hour to remove the binder. Next, a powder having the same composition as the calcined powder is laid on a zirconia setter, and a molded body is placed thereon, heated in an oxygen atmosphere at 100 ° C./hour, and sintered at 1700 ° C. for 1 hour. . The relative density of the obtained strontium / ruthenium oxide sintered body was 81%.
［実施例２］
最大粒子径が１０５μｍで、Ｄ５０が１２.４６μｍの金属ルテニウムを用いた以外は、上記実施例１と同様にして、仮焼成、成形、焼結を実施した。このとき、仮焼粉は、Ｘ線回折分析により、ストロンチウム・ルテニウム酸化物であることが確認できた。また、得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は８０％であった。
[Example 2]
Pre-firing, molding, and sintering were performed in the same manner as in Example 1 except that metal ruthenium having a maximum particle size of 105 μm and D50 of 12.46 μm was used. At this time, it was confirmed by X-ray diffraction analysis that the calcined powder was strontium / ruthenium oxide. The relative density of the obtained strontium / ruthenium oxide sintered body was 80%.
また、上記実施例１と同様に、仮焼粉について、Ｘ線回折により２θ＝３２度のピーク強度を１としたピーク強度比を調べたところ、２θ＝２８.０８度のピーク強度比は０.００８、及び２θ＝３５.０１度のピーク強度比は０.００４であった。 Similarly to Example 1 above, the calcined powder was examined by X-ray diffraction for a peak intensity ratio with a peak intensity of 2θ = 32 degrees of 1, and a peak intensity ratio of 2θ = 28.08 degrees was 0. The peak intensity ratio of 0.008 and 2θ = 35.01 degrees was 0.004.
［実施例３］
酸素雰囲気中での焼結温度を１６５０℃とした以外は、上記実施例１と同様にして、仮焼成、成形、焼結を実施した。このとき、仮焼粉は、Ｘ線回折分析により、ストロンチウム・ルテニウム酸化物であることが確認できた。また、得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は７７％であった。
[Example 3]
Temporary firing, molding, and sintering were performed in the same manner as in Example 1 except that the sintering temperature in an oxygen atmosphere was 1650 ° C. At this time, it was confirmed by X-ray diffraction analysis that the calcined powder was strontium / ruthenium oxide. The relative density of the obtained strontium / ruthenium oxide sintered body was 77%.
また、上記実施例１と同様に、仮焼粉について、Ｘ線回折により２θ＝３２度のピーク強度を１としたピーク強度比を調べたところ、２θ＝２８.０８度のピーク強度比は０.００５、及び２θ＝３５.０１度のピーク強度比は０.００６であった。 Similarly to Example 1 above, the calcined powder was examined by X-ray diffraction for a peak intensity ratio with a peak intensity of 2θ = 32 degrees of 1, and a peak intensity ratio of 2θ = 28.08 degrees was 0. The peak intensity ratio at 0.005 and 2θ = 35.01 degrees was 0.006.
［実施例４］
酸素雰囲気中での焼結温度を１６００℃とした以外は、上記実施例１と同様にして、仮焼成、成形、焼結を実施した。このとき、仮焼粉は、Ｘ線回折分析により、ストロンチウム・ルテニウム酸化物であることが確認できた。また、得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は７５％であった。
[Example 4]
Temporary firing, molding, and sintering were performed in the same manner as in Example 1 except that the sintering temperature in an oxygen atmosphere was 1600 ° C. At this time, it was confirmed by X-ray diffraction analysis that the calcined powder was strontium / ruthenium oxide. The relative density of the obtained strontium / ruthenium oxide sintered body was 75%.
また、上記実施例１と同様に、仮焼粉について、Ｘ線回折により２θ＝３２度のピーク強度を１としたピーク強度比を調べたところ、２θ＝２８.０８度のピーク強度比は０.００６、及び２θ＝３５.０１度のピーク強度比は０.００３であった。 Similarly to Example 1 above, the calcined powder was examined by X-ray diffraction for a peak intensity ratio with a peak intensity of 2θ = 32 degrees of 1, and a peak intensity ratio of 2θ = 28.08 degrees was 0. The peak intensity ratio at 0.006 and 2θ = 35.01 degrees was 0.003.
［比較例１］
最大粒子径が１２５μｍで、Ｄ５０が１７.２２μｍの金属ルテニウムを用いた以外は、上記実施例１と同様にして、仮焼成、成形、焼結を実施した。得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は６８％であった。
[Comparative Example 1]
Pre-firing, forming, and sintering were performed in the same manner as in Example 1 except that metal ruthenium having a maximum particle size of 125 μm and D50 of 17.22 μm was used. The relative density of the obtained strontium / ruthenium oxide sintered body was 68%.
また、上記実施例１と同様に、仮焼粉について、Ｘ線回折により２θ＝３２度のピーク強度を１としたピーク強度比を調べたところ、２θ＝２８.０８度のピーク強度比は０.０５２、及び２θ＝３５.０１度のピーク強度比は０.００５であった。 Similarly to Example 1 above, the calcined powder was examined by X-ray diffraction for a peak intensity ratio with a peak intensity of 2θ = 32 degrees of 1, and a peak intensity ratio of 2θ = 28.08 degrees was 0. The peak intensity ratio at 0.052 and 2θ = 35.01 degrees was 0.005.
［比較例２］
最大粒子径が１５５μｍで、Ｄ５０が２４.９１μｍの金属ルテニウムを用いた以外は、上記実施例１と同様にして、仮焼成、成形、焼結を実施した。得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は６７％であった。
[Comparative Example 2]
Pre-firing, molding, and sintering were performed in the same manner as in Example 1 except that metal ruthenium having a maximum particle size of 155 μm and D50 of 24.91 μm was used. The relative density of the obtained strontium / ruthenium oxide sintered body was 67%.
また、上記実施例１と同様に、仮焼粉について、Ｘ線回折により２θ＝３２度のピーク強度を１としたピーク強度比を調べたところ、２θ＝２８.０８度のピーク強度比は０.０３３、及び２θ＝３５.０１度のピーク強度比は０.０１３であった。 Similarly to Example 1 above, the calcined powder was examined by X-ray diffraction for a peak intensity ratio with a peak intensity of 2θ = 32 degrees of 1, and a peak intensity ratio of 2θ = 28.08 degrees was 0. The peak intensity ratio of 0.033 and 2θ = 35.01 degrees was 0.013.
［比較例３］
上記実施例１と同じ金属ルテニウムと炭酸ストロンチウムを原料とし、実施例１と同様にして仮焼成を行なった。得られた仮焼粉を粉砕する際に、実施例１の脱水エタノールに変えて純水を媒体とし、ジルコニアボールを用いたボールミルで１５時間粉砕した後、乾燥して粉砕粉とした。
[Comparative Example 3]
The same metal ruthenium and strontium carbonate as in Example 1 were used as raw materials, and calcined in the same manner as in Example 1. When the obtained calcined powder was pulverized, it was changed to the dehydrated ethanol of Example 1, using pure water as a medium, pulverized with a ball mill using zirconia balls for 15 hours, and then dried to obtain pulverized powder.
次に、得られた仮焼粉と粉砕粉について、上記実施例１と同様に、Ｘ線回折を行なったところ、粉砕前の仮焼粉に異相は見られなかったが、上記の仮焼粉を粉砕乾燥した後の粉砕粉には２θ＝２５.７度付近に炭酸ストロンチウムと思われる異相が見られた。また、仮焼粉の粉砕後のスラリーを濾過して、濾液を分析したところ、Ｓｒ量が１４ｍｇ／ｍｌ検出された。 Next, the obtained calcined powder and pulverized powder were subjected to X-ray diffraction in the same manner as in Example 1. As a result, no foreign phase was found in the calcined powder before pulverization. In the pulverized powder after pulverized and dried, a heterogeneous phase considered to be strontium carbonate was observed around 2θ = 25.7 °. Moreover, when the slurry after calcination of the calcined powder was filtered and the filtrate was analyzed, the amount of Sr was detected to be 14 mg / ml.
以上の結果から、純水を媒体にして仮焼粉を粉砕した際に、ストロンチウムが溶出して組成のずれを生じたことが判明した。そのため、この仮焼粉については焼結体を作製しなかった。 From the above results, it was found that when the calcined powder was pulverized using pure water as a medium, strontium was eluted to cause a composition shift. Therefore, a sintered body was not produced for this calcined powder.
［比較例４］
酸素雰囲気中での焼結温度を１５００℃とした以外は、上記実施例１と同様に仮焼成、成形、焼結を実施した。このとき、得られたストロンチウム・ルテニウム酸化物焼結体の相対密度は６５％であった。焼結温度が１５５０℃より低いため、焼結が十分に進行せず、密度が低下したことが分る。
[Comparative Example 4]
Temporary firing, molding, and sintering were performed in the same manner as in Example 1 except that the sintering temperature in an oxygen atmosphere was 1500 ° C. At this time, the relative density of the obtained strontium / ruthenium oxide sintered body was 65%. It can be seen that since the sintering temperature is lower than 1550 ° C., the sintering did not proceed sufficiently and the density was lowered.
以上の実施例１〜４及び比較例１〜４の結果を、原料の金属ルテニウムの粒度と仮焼粉のＸ線回折のピーク強度について表１に、及び焼結温度と焼結体の相対密度について表２に、それぞれまとめて示した。 The results of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1 for the particle size of the metal ruthenium as a raw material and the peak intensity of X-ray diffraction of the calcined powder, and the sintering temperature and the relative density of the sintered body. Are summarized in Table 2.
Claims (4)
In the X-ray diffraction pattern of the calcined powder after pulverization, the peak intensity ratios of 2θ = 28.08 degrees and 2θ = 35.01 degrees with respect to the peak intensity of 2θ = 32 degrees are both 0.01 or less. The manufacturing method of the strontium ruthenium oxide sintered compact in any one of Claims 1-3 characterized by the above-mentioned.
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| CN113735566A (en) * | 2021-09-08 | 2021-12-03 | 成都先锋材料有限公司 | Strontium ruthenate material and preparation method and application thereof |
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| KR100840893B1 (en) | 2007-05-01 | 2008-06-24 | 대주전자재료 주식회사 | Manufacturing method of strontium type conducting powder for pb free thin film resistance paste |
| CN113735566A (en) * | 2021-09-08 | 2021-12-03 | 成都先锋材料有限公司 | Strontium ruthenate material and preparation method and application thereof |
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